1 /* vi: set sw=4 ts=4: */
3 * A prototype Bourne shell grammar parser.
4 * Intended to follow the original Thompson and Ritchie
5 * "small and simple is beautiful" philosophy, which
6 * incidentally is a good match to today's BusyBox.
8 * Copyright (C) 2000,2001 Larry Doolittle <larry@doolittle.boa.org>
9 * Copyright (C) 2008,2009 Denys Vlasenko <vda.linux@googlemail.com>
12 * The parser routines proper are all original material, first
13 * written Dec 2000 and Jan 2001 by Larry Doolittle. The
14 * execution engine, the builtins, and much of the underlying
15 * support has been adapted from busybox-0.49pre's lash, which is
16 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
17 * written by Erik Andersen <andersen@codepoet.org>. That, in turn,
18 * is based in part on ladsh.c, by Michael K. Johnson and Erik W.
19 * Troan, which they placed in the public domain. I don't know
20 * how much of the Johnson/Troan code has survived the repeated
24 * o_addchr derived from similar w_addchar function in glibc-2.2.
25 * parse_redirect, redirect_opt_num, and big chunks of main
26 * and many builtins derived from contributions by Erik Andersen.
27 * Miscellaneous bugfixes from Matt Kraai.
29 * There are two big (and related) architecture differences between
30 * this parser and the lash parser. One is that this version is
31 * actually designed from the ground up to understand nearly all
32 * of the Bourne grammar. The second, consequential change is that
33 * the parser and input reader have been turned inside out. Now,
34 * the parser is in control, and asks for input as needed. The old
35 * way had the input reader in control, and it asked for parsing to
36 * take place as needed. The new way makes it much easier to properly
37 * handle the recursion implicit in the various substitutions, especially
38 * across continuation lines.
40 * POSIX syntax not implemented:
42 * <(list) and >(list) Process Substitution
45 * Bash stuff (maybe optionally enable?):
46 * &> and >& redirection of stdout+stderr
48 * reserved words: [[ ]] function select
49 * substrings ${var:1:5}
52 * grep for "TODO" and fix (some of them are easy)
53 * change { and } from special chars to reserved words
54 * builtins: return, ulimit
55 * follow IFS rules more precisely, including update semantics
56 * figure out what to do with backslash-newline
57 * continuation lines, both explicit and implicit - done?
59 * separate job control from interactiveness
60 * (testcase: booting with init=/bin/hush does not show prompt (2009-04))
62 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
64 #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */
66 /* #include <dmalloc.h> */
73 # define PIPE_BUF 4096 /* amount of buffering in a pipe */
77 /* Debug build knobs */
78 #define LEAK_HUNTING 0
79 #define BUILD_AS_NOMMU 0
80 /* Enable/disable sanity checks. Ok to enable in production,
81 * only adds a bit of bloat. Set to >1 to get non-production level verbosity.
82 * Keeping 1 for now even in released versions.
92 # define USE_FOR_NOMMU(...) __VA_ARGS__
93 # define USE_FOR_MMU(...)
96 #if defined SINGLE_APPLET_MAIN
97 /* STANDALONE does not make sense, and won't compile */
98 # undef CONFIG_FEATURE_SH_STANDALONE
99 # undef ENABLE_FEATURE_SH_STANDALONE
100 # undef USE_FEATURE_SH_STANDALONE
101 # define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
102 # define ENABLE_FEATURE_SH_STANDALONE 0
103 # define USE_FEATURE_SH_STANDALONE(...)
104 # define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
107 #if !ENABLE_HUSH_INTERACTIVE
108 # undef ENABLE_FEATURE_EDITING
109 # define ENABLE_FEATURE_EDITING 0
110 # undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
111 # define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
114 /* Do we support ANY keywords? */
115 #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
116 # define HAS_KEYWORDS 1
117 # define IF_HAS_KEYWORDS(...) __VA_ARGS__
118 # define IF_HAS_NO_KEYWORDS(...)
120 # define HAS_KEYWORDS 0
121 # define IF_HAS_KEYWORDS(...)
122 # define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__
125 /* If you comment out one of these below, it will be #defined later
126 * to perform debug printfs to stderr: */
127 #define debug_printf(...) do {} while (0)
128 /* Finer-grained debug switches */
129 #define debug_printf_parse(...) do {} while (0)
130 #define debug_print_tree(a, b) do {} while (0)
131 #define debug_printf_exec(...) do {} while (0)
132 #define debug_printf_env(...) do {} while (0)
133 #define debug_printf_jobs(...) do {} while (0)
134 #define debug_printf_expand(...) do {} while (0)
135 #define debug_printf_glob(...) do {} while (0)
136 #define debug_printf_list(...) do {} while (0)
137 #define debug_printf_subst(...) do {} while (0)
138 #define debug_printf_clean(...) do {} while (0)
140 #define ERR_PTR ((void*)(long)1)
142 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
144 #define SPECIAL_VAR_SYMBOL 3
146 static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="BB_VER;
148 /* This supports saving pointers malloced in vfork child,
149 * to be freed in the parent.
152 typedef struct nommu_save_t {
156 char **argv_from_re_execing;
160 /* The descrip member of this structure is only used to make
161 * debugging output pretty */
162 static const struct {
164 signed char default_fd;
168 { O_RDONLY, 0, "<" },
169 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
170 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
171 { O_RDONLY, 0, "<<" },
172 { O_CREAT|O_RDWR, 1, "<>" },
173 /* Should not be needed. Bogus default_fd helps in debugging */
174 /* { O_RDONLY, 77, "<<" }, */
177 typedef enum reserved_style {
186 #if ENABLE_HUSH_LOOPS
193 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
198 /* two pseudo-keywords support contrived "case" syntax: */
199 RES_MATCH , /* "word)" */
200 RES_CASEI , /* "this command is inside CASE" */
207 typedef struct o_string {
209 int length; /* position where data is appended */
211 /* Protect newly added chars against globbing
212 * (by prepending \ to *, ?, [, \) */
215 /* At least some part of the string was inside '' or "",
216 * possibly empty one: word"", wo''rd etc. */
218 smallint has_empty_slot;
219 smallint o_assignment; /* 0:maybe, 1:yes, 2:no */
222 MAYBE_ASSIGNMENT = 0,
223 DEFINITELY_ASSIGNMENT = 1,
225 WORD_IS_KEYWORD = 3, /* not assigment, but next word may be: "if v=xyz cmd;" */
227 /* Used for initialization: o_string foo = NULL_O_STRING; */
228 #define NULL_O_STRING { NULL }
230 /* I can almost use ordinary FILE*. Is open_memstream() universally
231 * available? Where is it documented? */
232 typedef struct in_str {
234 /* eof_flag=1: last char in ->p is really an EOF */
235 char eof_flag; /* meaningless if ->p == NULL */
237 #if ENABLE_HUSH_INTERACTIVE
239 smallint promptmode; /* 0: PS1, 1: PS2 */
242 int (*get) (struct in_str *);
243 int (*peek) (struct in_str *);
245 #define i_getch(input) ((input)->get(input))
246 #define i_peek(input) ((input)->peek(input))
248 struct redir_struct {
249 struct redir_struct *next;
250 char *rd_filename; /* filename */
251 int rd_fd; /* fd to redirect */
252 /* fd to redirect to, or -3 if rd_fd is to be closed (n>&-) */
254 smallint rd_type; /* (enum redir_type) */
255 /* note: for heredocs, rd_filename contains heredoc delimiter,
256 * and subsequently heredoc itself; and rd_dup is a bitmask:
257 * 1: do we need to trim leading tabs?
258 * 2: is heredoc quoted (<<'delim' syntax) ?
261 typedef enum redir_type {
262 REDIRECT_INVALID = 0,
264 REDIRECT_OVERWRITE = 2,
266 REDIRECT_HEREDOC = 4,
268 REDIRECT_HEREDOC2 = 6, /* REDIRECT_HEREDOC after heredoc is loaded */
271 REDIRFD_SYNTAX_ERR = -2,
272 REDIRFD_TO_FILE = -1,
273 /* otherwise, rd_fd is redirected to rd_dup */
275 HEREDOC_SKIPTABS = 1,
281 pid_t pid; /* 0 if exited */
282 int assignment_cnt; /* how many argv[i] are assignments? */
283 smallint is_stopped; /* is the command currently running? */
284 smallint grp_type; /* GRP_xxx */
286 #define GRP_SUBSHELL 1
287 #if ENABLE_HUSH_FUNCTIONS
288 # define GRP_FUNCTION 2
290 struct pipe *group; /* if non-NULL, this "command" is { list },
291 * ( list ), or a compound statement */
293 char *group_as_string;
295 #if ENABLE_HUSH_FUNCTIONS
296 struct function *child_func;
297 /* This field is used to prevent a bug here:
298 * while...do f1() {a;}; f1; f1 {b;}; f1; done
299 * When we execute "f1() {a;}" cmd, we create new function and clear
300 * cmd->group, cmd->group_as_string, cmd->argv[0].
301 * when we execute "f1 {b;}", we notice that f1 exists,
302 * and that it's "parent cmd" struct is still "alive",
303 * we put those fields back into cmd->xxx
304 * (struct function has ->parent_cmd ptr to facilitate that).
305 * When we loop back, we can execute "f1() {a;}" again and set f1 correctly.
306 * Without this trick, loop would execute a;b;b;b;...
307 * instead of correct sequence a;b;a;b;...
308 * When command is freed, it severs the link
309 * (sets ->child_func->parent_cmd to NULL).
312 char **argv; /* command name and arguments */
313 /* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
314 * and on execution these are substituted with their values.
315 * Substitution can make _several_ words out of one argv[n]!
316 * Example: argv[0]=='.^C*^C.' here: echo .$*.
317 * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
319 struct redir_struct *redirects; /* I/O redirections */
324 int num_cmds; /* total number of commands in pipe */
325 int alive_cmds; /* number of commands running (not exited) */
326 int stopped_cmds; /* number of commands alive, but stopped */
328 int jobid; /* job number */
329 pid_t pgrp; /* process group ID for the job */
330 char *cmdtext; /* name of job */
332 struct command *cmds; /* array of commands in pipe */
333 smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
334 IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */
335 IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */
337 typedef enum pipe_style {
344 /* This holds pointers to the various results of parsing */
345 struct parse_context {
346 /* linked list of pipes */
347 struct pipe *list_head;
348 /* last pipe (being constructed right now) */
350 /* last command in pipe (being constructed right now) */
351 struct command *command;
352 /* last redirect in command->redirects list */
353 struct redir_struct *pending_redirect;
359 smallint ctx_inverted; /* "! cmd | cmd" */
361 smallint ctx_dsemicolon; /* ";;" seen */
363 /* bitmask of FLAG_xxx, for figuring out valid reserved words */
365 /* group we are enclosed in:
366 * example: "if pipe1; pipe2; then pipe3; fi"
367 * when we see "if" or "then", we malloc and copy current context,
368 * and make ->stack point to it. then we parse pipeN.
369 * when closing "then" / fi" / whatever is found,
370 * we move list_head into ->stack->command->group,
371 * copy ->stack into current context, and delete ->stack.
372 * (parsing of { list } and ( list ) doesn't use this method)
374 struct parse_context *stack;
378 /* On program start, environ points to initial environment.
379 * putenv adds new pointers into it, unsetenv removes them.
380 * Neither of these (de)allocates the strings.
381 * setenv allocates new strings in malloc space and does putenv,
382 * and thus setenv is unusable (leaky) for shell's purposes */
383 #define setenv(...) setenv_is_leaky_dont_use()
385 struct variable *next;
386 char *varstr; /* points to "name=" portion */
387 int max_len; /* if > 0, name is part of initial env; else name is malloced */
388 smallint flg_export; /* putenv should be done on this var */
389 smallint flg_read_only;
397 #if ENABLE_HUSH_FUNCTIONS
399 struct function *next;
401 struct command *parent_cmd;
404 char *body_as_string;
410 /* "Globals" within this file */
411 /* Sorted roughly by size (smaller offsets == smaller code) */
413 #if ENABLE_HUSH_INTERACTIVE
414 /* 'interactive_fd' is a fd# open to ctty, if we have one
415 * _AND_ if we decided to act interactively */
419 #define G_interactive_fd (G.interactive_fd)
421 #define G_interactive_fd 0
423 #if ENABLE_FEATURE_EDITING
424 line_input_t *line_input_state;
430 pid_t saved_tty_pgrp;
432 struct pipe *job_list;
433 struct pipe *toplevel_list;
435 smallint flag_SIGINT;
436 #if ENABLE_HUSH_LOOPS
437 smallint flag_break_continue;
440 smallint exiting; /* used to prevent EXIT trap recursion */
441 /* These four support $?, $#, and $1 */
442 smalluint last_exitcode;
443 /* are global_argv and global_argv[1..n] malloced? (note: not [0]) */
444 smalluint global_args_malloced;
445 /* how many non-NULL argv's we have. NB: $# + 1 */
449 char *argv0_for_re_execing;
451 #if ENABLE_HUSH_LOOPS
452 unsigned depth_break_continue;
453 unsigned depth_of_loop;
457 struct variable *top_var; /* = &G.shell_ver (set in main()) */
458 struct variable shell_ver;
459 #if ENABLE_HUSH_FUNCTIONS
460 struct function *top_func;
462 /* Signal and trap handling */
463 // unsigned count_SIGCHLD;
464 // unsigned handled_SIGCHLD;
465 /* which signals have non-DFL handler (even with no traps set)? */
466 unsigned non_DFL_mask;
467 char **traps; /* char *traps[NSIG] */
468 sigset_t blocked_set;
469 sigset_t inherited_set;
471 unsigned long memleak_value;
474 char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
476 #define G (*ptr_to_globals)
477 /* Not #defining name to G.name - this quickly gets unwieldy
478 * (too many defines). Also, I actually prefer to see when a variable
479 * is global, thus "G." prefix is a useful hint */
480 #define INIT_G() do { \
481 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
485 /* Function prototypes for builtins */
486 static int builtin_cd(char **argv);
487 static int builtin_echo(char **argv);
488 static int builtin_eval(char **argv);
489 static int builtin_exec(char **argv);
490 static int builtin_exit(char **argv);
491 static int builtin_export(char **argv);
493 static int builtin_fg_bg(char **argv);
494 static int builtin_jobs(char **argv);
497 static int builtin_help(char **argv);
500 static int builtin_memleak(char **argv);
502 static int builtin_pwd(char **argv);
503 static int builtin_read(char **argv);
504 static int builtin_set(char **argv);
505 static int builtin_shift(char **argv);
506 static int builtin_source(char **argv);
507 static int builtin_test(char **argv);
508 static int builtin_trap(char **argv);
509 static int builtin_true(char **argv);
510 static int builtin_umask(char **argv);
511 static int builtin_unset(char **argv);
512 static int builtin_wait(char **argv);
513 #if ENABLE_HUSH_LOOPS
514 static int builtin_break(char **argv);
515 static int builtin_continue(char **argv);
518 /* Table of built-in functions. They can be forked or not, depending on
519 * context: within pipes, they fork. As simple commands, they do not.
520 * When used in non-forking context, they can change global variables
521 * in the parent shell process. If forked, of course they cannot.
522 * For example, 'unset foo | whatever' will parse and run, but foo will
523 * still be set at the end. */
524 struct built_in_command {
526 int (*function)(char **argv);
529 #define BLTIN(cmd, func, help) { cmd, func, help }
531 #define BLTIN(cmd, func, help) { cmd, func }
535 /* For now, echo and test are unconditionally enabled.
536 * Maybe make it configurable? */
537 static const struct built_in_command bltins[] = {
538 BLTIN("." , builtin_source , "Run commands in a file"),
539 BLTIN(":" , builtin_true , "No-op"),
540 BLTIN("[" , builtin_test , "Test condition"),
542 BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
544 #if ENABLE_HUSH_LOOPS
545 BLTIN("break" , builtin_break , "Exit from a loop"),
547 BLTIN("cd" , builtin_cd , "Change directory"),
548 #if ENABLE_HUSH_LOOPS
549 BLTIN("continue", builtin_continue, "Start new loop iteration"),
551 BLTIN("echo" , builtin_echo , "Write to stdout"),
552 BLTIN("eval" , builtin_eval , "Construct and run shell command"),
553 BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
554 BLTIN("exit" , builtin_exit , "Exit"),
555 BLTIN("export" , builtin_export , "Set environment variable"),
557 BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
560 BLTIN("help" , builtin_help , "List shell built-in commands"),
563 BLTIN("jobs" , builtin_jobs , "List active jobs"),
566 BLTIN("memleak" , builtin_memleak , "Debug tool"),
568 BLTIN("pwd" , builtin_pwd , "Print current directory"),
569 BLTIN("read" , builtin_read , "Input environment variable"),
570 // BLTIN("return" , builtin_return , "Return from a function"),
571 BLTIN("set" , builtin_set , "Set/unset shell local variables"),
572 BLTIN("shift" , builtin_shift , "Shift positional parameters"),
573 BLTIN("test" , builtin_test , "Test condition"),
574 BLTIN("trap" , builtin_trap , "Trap signals"),
575 // BLTIN("ulimit" , builtin_return , "Control resource limits"),
576 BLTIN("umask" , builtin_umask , "Set file creation mask"),
577 BLTIN("unset" , builtin_unset , "Unset environment variable"),
578 BLTIN("wait" , builtin_wait , "Wait for process"),
585 /* prevent disasters with G.debug_indent < 0 */
586 # define indent() fprintf(stderr, "%*s", (G.debug_indent * 2) & 0xff, "")
587 # define debug_enter() (G.debug_indent++)
588 # define debug_leave() (G.debug_indent--)
590 # define indent() ((void)0)
591 # define debug_enter() ((void)0)
592 # define debug_leave() ((void)0)
596 # define debug_printf(...) (indent(), fprintf(stderr, __VA_ARGS__))
599 #ifndef debug_printf_parse
600 # define debug_printf_parse(...) (indent(), fprintf(stderr, __VA_ARGS__))
603 #ifndef debug_printf_exec
604 #define debug_printf_exec(...) (indent(), fprintf(stderr, __VA_ARGS__))
607 #ifndef debug_printf_env
608 # define debug_printf_env(...) (indent(), fprintf(stderr, __VA_ARGS__))
611 #ifndef debug_printf_jobs
612 # define debug_printf_jobs(...) (indent(), fprintf(stderr, __VA_ARGS__))
613 # define DEBUG_JOBS 1
615 # define DEBUG_JOBS 0
618 #ifndef debug_printf_expand
619 # define debug_printf_expand(...) (indent(), fprintf(stderr, __VA_ARGS__))
620 # define DEBUG_EXPAND 1
622 # define DEBUG_EXPAND 0
625 #ifndef debug_printf_glob
626 # define debug_printf_glob(...) (indent(), fprintf(stderr, __VA_ARGS__))
627 # define DEBUG_GLOB 1
629 # define DEBUG_GLOB 0
632 #ifndef debug_printf_list
633 # define debug_printf_list(...) (indent(), fprintf(stderr, __VA_ARGS__))
636 #ifndef debug_printf_subst
637 # define debug_printf_subst(...) (indent(), fprintf(stderr, __VA_ARGS__))
640 #ifndef debug_printf_clean
641 # define debug_printf_clean(...) (indent(), fprintf(stderr, __VA_ARGS__))
642 # define DEBUG_CLEAN 1
644 # define DEBUG_CLEAN 0
648 static void debug_print_strings(const char *prefix, char **vv)
651 fprintf(stderr, "%s:\n", prefix);
653 fprintf(stderr, " '%s'\n", *vv++);
656 #define debug_print_strings(prefix, vv) ((void)0)
660 /* Leak hunting. Use hush_leaktool.sh for post-processing.
663 static void *xxmalloc(int lineno, size_t size)
665 void *ptr = xmalloc((size + 0xff) & ~0xff);
666 fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
669 static void *xxrealloc(int lineno, void *ptr, size_t size)
671 ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
672 fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
675 static char *xxstrdup(int lineno, const char *str)
677 char *ptr = xstrdup(str);
678 fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
681 static void xxfree(void *ptr)
683 fdprintf(2, "free %p\n", ptr);
686 #define xmalloc(s) xxmalloc(__LINE__, s)
687 #define xrealloc(p, s) xxrealloc(__LINE__, p, s)
688 #define xstrdup(s) xxstrdup(__LINE__, s)
689 #define free(p) xxfree(p)
693 /* Syntax and runtime errors. They always abort scripts.
694 * In interactive use they usually discard unparsed and/or unexecuted commands
695 * and return to the prompt.
696 * HUSH_DEBUG >= 2 prints line number in this file where it was detected.
699 # define die_if_script(lineno, fmt...) die_if_script(fmt)
700 # define syntax_error(lineno, msg) syntax_error(msg)
701 # define syntax_error_at(lineno, msg) syntax_error_at(msg)
702 # define syntax_error_unterm_ch(lineno, ch) syntax_error_unterm_ch(ch)
703 # define syntax_error_unterm_str(lineno, s) syntax_error_unterm_str(s)
704 # define syntax_error_unexpected_ch(lineno, ch) syntax_error_unexpected_ch(ch)
707 static void die_if_script(unsigned lineno, const char *fmt, ...)
712 bb_error_msg("hush.c:%u", lineno);
715 bb_verror_msg(fmt, p, NULL);
717 if (!G_interactive_fd)
721 static void syntax_error(unsigned lineno, const char *msg)
724 die_if_script(lineno, "syntax error: %s", msg);
726 die_if_script(lineno, "syntax error", NULL);
729 static void syntax_error_at(unsigned lineno, const char *msg)
731 die_if_script(lineno, "syntax error at '%s'", msg);
734 /* It so happens that all such cases are totally fatal
735 * even if shell is interactive: EOF while looking for closing
736 * delimiter. There is nowhere to read stuff from after that,
737 * it's EOF! The only choice is to terminate.
739 static void syntax_error_unterm_ch(unsigned lineno, char ch) NORETURN;
740 static void syntax_error_unterm_ch(unsigned lineno, char ch)
745 die_if_script(lineno, "syntax error: unterminated %s", msg);
749 static void syntax_error_unterm_str(unsigned lineno, const char *s)
751 die_if_script(lineno, "syntax error: unterminated %s", s);
754 static void syntax_error_unexpected_ch(unsigned lineno, char ch)
759 die_if_script(lineno, "syntax error: unexpected %s", msg);
763 # undef die_if_script
765 # undef syntax_error_at
766 # undef syntax_error_unterm_ch
767 # undef syntax_error_unterm_str
768 # undef syntax_error_unexpected_ch
770 # define die_if_script(fmt...) die_if_script(__LINE__, fmt)
771 # define syntax_error(msg) syntax_error(__LINE__, msg)
772 # define syntax_error_at(msg) syntax_error_at(__LINE__, msg)
773 # define syntax_error_unterm_ch(ch) syntax_error_unterm_ch(__LINE__, ch)
774 # define syntax_error_unterm_str(s) syntax_error_unterm_str(__LINE__, s)
775 # define syntax_error_unexpected_ch(ch) syntax_error_unexpected_ch(__LINE__, ch)
781 static int glob_needed(const char *s)
786 if (*s == '*' || *s == '[' || *s == '?')
793 static int is_well_formed_var_name(const char *s, char terminator)
795 if (!s || !(isalpha(*s) || *s == '_'))
798 while (isalnum(*s) || *s == '_')
800 return *s == terminator;
803 /* Replace each \x with x in place, return ptr past NUL. */
804 static char *unbackslash(char *src)
810 if ((*dst++ = *src++) == '\0')
816 static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
837 v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
838 v[count1 + count2] = NULL;
841 v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
845 static char **xx_add_strings_to_strings(int lineno, char **strings, char **add, int need_to_dup)
847 char **ptr = add_strings_to_strings(strings, add, need_to_dup);
848 fdprintf(2, "line %d: add_strings_to_strings %p\n", lineno, ptr);
851 #define add_strings_to_strings(strings, add, need_to_dup) \
852 xx_add_strings_to_strings(__LINE__, strings, add, need_to_dup)
855 static char **add_string_to_strings(char **strings, char *add)
860 return add_strings_to_strings(strings, v, /*dup:*/ 0);
863 static char **xx_add_string_to_strings(int lineno, char **strings, char *add)
865 char **ptr = add_string_to_strings(strings, add);
866 fdprintf(2, "line %d: add_string_to_strings %p\n", lineno, ptr);
869 #define add_string_to_strings(strings, add) \
870 xx_add_string_to_strings(__LINE__, strings, add)
873 static void putenv_all(char **strings)
878 debug_printf_env("putenv '%s'\n", *strings);
883 static char **putenv_all_and_save_old(char **strings)
893 eq = strchr(*strings, '=');
896 v = getenv(*strings);
899 /* v points to VAL in VAR=VAL, go back to VAR */
900 v -= (eq - *strings) + 1;
901 old = add_string_to_strings(old, v);
910 static void free_strings_and_unsetenv(char **strings, int unset)
920 debug_printf_env("unsetenv '%s'\n", *v);
928 static void free_strings(char **strings)
930 free_strings_and_unsetenv(strings, 0);
934 /* Basic theory of signal handling in shell
935 * ========================================
936 * This does not describe what hush does, rather, it is current understanding
937 * what it _should_ do. If it doesn't, it's a bug.
938 * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
940 * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
941 * is finished or backgrounded. It is the same in interactive and
942 * non-interactive shells, and is the same regardless of whether
943 * a user trap handler is installed or a shell special one is in effect.
944 * ^C or ^Z from keyboard seem to execute "at once" because it usually
945 * backgrounds (i.e. stops) or kills all members of currently running
948 * Wait builtin in interruptible by signals for which user trap is set
949 * or by SIGINT in interactive shell.
951 * Trap handlers will execute even within trap handlers. (right?)
953 * User trap handlers are forgotten when subshell ("(cmd)") is entered.
955 * If job control is off, backgrounded commands ("cmd &")
956 * have SIGINT, SIGQUIT set to SIG_IGN.
958 * Commands run in command substitution ("`cmd`")
959 * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
961 * Ordinary commands have signals set to SIG_IGN/DFL set as inherited
962 * by the shell from its parent.
964 * Siganls which differ from SIG_DFL action
965 * (note: child (i.e., [v]forked) shell is not an interactive shell):
968 * SIGTERM (interactive): ignore
969 * SIGHUP (interactive):
970 * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
971 * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
972 * Note that ^Z is handled not by trapping SIGTSTP, but by seeing
973 * that all pipe members are stopped. Try this in bash:
974 * while :; do :; done - ^Z does not background it
975 * (while :; do :; done) - ^Z backgrounds it
976 * SIGINT (interactive): wait for last pipe, ignore the rest
977 * of the command line, show prompt. NB: ^C does not send SIGINT
978 * to interactive shell while shell is waiting for a pipe,
979 * since shell is bg'ed (is not in foreground process group).
980 * Example 1: this waits 5 sec, but does not execute ls:
981 * "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
982 * Example 2: this does not wait and does not execute ls:
983 * "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
984 * Example 3: this does not wait 5 sec, but executes ls:
985 * "sleep 5; ls -l" + press ^C
987 * (What happens to signals which are IGN on shell start?)
988 * (What happens with signal mask on shell start?)
990 * Implementation in hush
991 * ======================
992 * We use in-kernel pending signal mask to determine which signals were sent.
993 * We block all signals which we don't want to take action immediately,
994 * i.e. we block all signals which need to have special handling as described
995 * above, and all signals which have traps set.
996 * After each pipe execution, we extract any pending signals via sigtimedwait()
999 * unsigned non_DFL_mask: a mask of such "special" signals
1000 * sigset_t blocked_set: current blocked signal set
1003 * clear bit in blocked_set unless it is also in non_DFL_mask
1004 * "trap 'cmd' SIGxxx":
1005 * set bit in blocked_set (even if 'cmd' is '')
1006 * after [v]fork, if we plan to be a shell:
1007 * nothing for {} child shell (say, "true | { true; true; } | true")
1008 * unset all traps if () shell.
1009 * after [v]fork, if we plan to exec:
1010 * POSIX says pending signal mask is cleared in child - no need to clear it.
1011 * Restore blocked signal set to one inherited by shell just prior to exec.
1013 * Note: as a result, we do not use signal handlers much. The only uses
1014 * are to count SIGCHLDs [disabled - bug somewhere, + bloat]
1015 * and to restore tty pgrp on signal-induced exit.
1018 //static void SIGCHLD_handler(int sig UNUSED_PARAM)
1020 // G.count_SIGCHLD++;
1023 static int check_and_run_traps(int sig)
1025 static const struct timespec zero_timespec = { 0, 0 };
1026 smalluint save_rcode;
1032 sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec);
1037 if (G.traps && G.traps[sig]) {
1038 if (G.traps[sig][0]) {
1039 /* We have user-defined handler */
1040 char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL };
1041 save_rcode = G.last_exitcode;
1044 G.last_exitcode = save_rcode;
1045 } /* else: "" trap, ignoring signal */
1048 /* not a trap: special action */
1051 // G.count_SIGCHLD++;
1060 default: /* ignored: */
1061 /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
1070 /* After [v]fork, in child: do not restore tty pgrp on xfunc death */
1071 #define disable_restore_tty_pgrp_on_exit() (die_sleep = 0)
1072 /* After [v]fork, in parent: restore tty pgrp on xfunc death */
1073 #define enable_restore_tty_pgrp_on_exit() (die_sleep = -1)
1075 /* Restores tty foreground process group, and exits.
1076 * May be called as signal handler for fatal signal
1077 * (will faithfully resend signal to itself, producing correct exit state)
1078 * or called directly with -EXITCODE.
1079 * We also call it if xfunc is exiting. */
1080 static void sigexit(int sig) NORETURN;
1081 static void sigexit(int sig)
1083 /* Disable all signals: job control, SIGPIPE, etc. */
1084 sigprocmask_allsigs(SIG_BLOCK);
1086 /* Careful: we can end up here after [v]fork. Do not restore
1087 * tty pgrp then, only top-level shell process does that */
1088 if (G_interactive_fd && getpid() == G.root_pid)
1089 tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
1091 /* Not a signal, just exit */
1095 kill_myself_with_sig(sig); /* does not return */
1099 #define disable_restore_tty_pgrp_on_exit() ((void)0)
1100 #define enable_restore_tty_pgrp_on_exit() ((void)0)
1104 /* Restores tty foreground process group, and exits. */
1105 static void hush_exit(int exitcode) NORETURN;
1106 static void hush_exit(int exitcode)
1108 if (G.exiting <= 0 && G.traps && G.traps[0] && G.traps[0][0]) {
1109 /* Prevent recursion:
1110 * trap "echo Hi; exit" EXIT; exit
1112 char *argv[] = { NULL, G.traps[0], NULL };
1120 fflush(NULL); /* flush all streams */
1121 sigexit(- (exitcode & 0xff));
1128 static const char *set_cwd(void)
1130 /* xrealloc_getcwd_or_warn(arg) calls free(arg),
1131 * we must not try to free(bb_msg_unknown) */
1132 if (G.cwd == bb_msg_unknown)
1134 G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
1136 G.cwd = bb_msg_unknown;
1141 /* Get/check local shell variables */
1142 static struct variable *get_local_var(const char *name)
1144 struct variable *cur;
1150 for (cur = G.top_var; cur; cur = cur->next) {
1151 if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
1157 static const char *get_local_var_value(const char *src)
1159 struct variable *var = get_local_var(src);
1161 return strchr(var->varstr, '=') + 1;
1165 /* str holds "NAME=VAL" and is expected to be malloced.
1166 * We take ownership of it.
1170 * -1: if NAME is set, leave export status alone
1171 * if NAME is not set, do not export
1172 * flg_read_only is set only when we handle -R var=val
1175 #define set_local_var(str, flg_export, flg_read_only) \
1176 set_local_var(str, flg_export)
1178 static int set_local_var(char *str, int flg_export, int flg_read_only)
1180 struct variable *cur;
1184 value = strchr(str, '=');
1185 if (!value) { /* not expected to ever happen? */
1190 name_len = value - str + 1; /* including '=' */
1191 cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
1193 if (strncmp(cur->varstr, str, name_len) != 0) {
1195 /* Bail out. Note that now cur points
1196 * to last var in linked list */
1202 /* We found an existing var with this name */
1204 if (cur->flg_read_only) {
1208 bb_error_msg("%s: readonly variable", str);
1212 debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
1213 unsetenv(str); /* just in case */
1215 if (strcmp(cur->varstr, str) == 0) {
1220 if (cur->max_len >= strlen(str)) {
1221 /* This one is from startup env, reuse space */
1222 strcpy(cur->varstr, str);
1225 /* max_len == 0 signifies "malloced" var, which we can
1226 * (and has to) free */
1230 goto set_str_and_exp;
1233 /* Not found - create next variable struct */
1234 cur->next = xzalloc(sizeof(*cur));
1240 cur->flg_read_only = flg_read_only;
1243 if (flg_export == 1)
1244 cur->flg_export = 1;
1245 if (cur->flg_export) {
1246 debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
1247 return putenv(cur->varstr);
1252 static int unset_local_var(const char *name)
1254 struct variable *cur;
1255 struct variable *prev = prev; /* for gcc */
1259 return EXIT_SUCCESS;
1260 name_len = strlen(name);
1263 if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
1264 if (cur->flg_read_only) {
1265 bb_error_msg("%s: readonly variable", name);
1266 return EXIT_FAILURE;
1268 /* prev is ok to use here because 1st variable, HUSH_VERSION,
1269 * is ro, and we cannot reach this code on the 1st pass */
1270 prev->next = cur->next;
1271 debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
1272 bb_unsetenv(cur->varstr);
1276 return EXIT_SUCCESS;
1281 return EXIT_SUCCESS;
1284 #if ENABLE_SH_MATH_SUPPORT
1285 #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c)))
1286 #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c)))
1287 static char *endofname(const char *name)
1295 if (!is_in_name(*p))
1301 static void arith_set_local_var(const char *name, const char *val, int flags)
1303 /* arith code doesnt malloc space, so do it for it */
1304 char *var = xasprintf("%s=%s", name, val);
1305 set_local_var(var, flags, 0);
1313 static int static_get(struct in_str *i)
1322 static int static_peek(struct in_str *i)
1327 #if ENABLE_HUSH_INTERACTIVE
1329 static void cmdedit_set_initial_prompt(void)
1331 if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1332 G.PS1 = getenv("PS1");
1339 static const char* setup_prompt_string(int promptmode)
1341 const char *prompt_str;
1342 debug_printf("setup_prompt_string %d ", promptmode);
1343 if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1344 /* Set up the prompt */
1345 if (promptmode == 0) { /* PS1 */
1347 G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#');
1352 prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
1353 debug_printf("result '%s'\n", prompt_str);
1357 static void get_user_input(struct in_str *i)
1360 const char *prompt_str;
1362 prompt_str = setup_prompt_string(i->promptmode);
1363 #if ENABLE_FEATURE_EDITING
1364 /* Enable command line editing only while a command line
1365 * is actually being read */
1368 /* buglet: SIGINT will not make new prompt to appear _at once_,
1369 * only after <Enter>. (^C will work) */
1370 r = read_line_input(prompt_str, G.user_input_buf, BUFSIZ-1, G.line_input_state);
1371 /* catch *SIGINT* etc (^C is handled by read_line_input) */
1372 check_and_run_traps(0);
1373 } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */
1374 i->eof_flag = (r < 0);
1375 if (i->eof_flag) { /* EOF/error detected */
1376 G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
1377 G.user_input_buf[1] = '\0';
1382 fputs(prompt_str, stdout);
1384 G.user_input_buf[0] = r = fgetc(i->file);
1385 /*G.user_input_buf[1] = '\0'; - already is and never changed */
1386 //do we need check_and_run_traps(0)? (maybe only if stdin)
1387 } while (G.flag_SIGINT);
1388 i->eof_flag = (r == EOF);
1390 i->p = G.user_input_buf;
1393 #endif /* INTERACTIVE */
1395 /* This is the magic location that prints prompts
1396 * and gets data back from the user */
1397 static int file_get(struct in_str *i)
1401 /* If there is data waiting, eat it up */
1402 if (i->p && *i->p) {
1403 #if ENABLE_HUSH_INTERACTIVE
1407 if (i->eof_flag && !*i->p)
1409 /* note: ch is never NUL */
1411 /* need to double check i->file because we might be doing something
1412 * more complicated by now, like sourcing or substituting. */
1413 #if ENABLE_HUSH_INTERACTIVE
1414 if (G_interactive_fd && i->promptme && i->file == stdin) {
1417 } while (!*i->p); /* need non-empty line */
1418 i->promptmode = 1; /* PS2 */
1423 do ch = fgetc(i->file); while (ch == '\0');
1425 debug_printf("file_get: got '%c' %d\n", ch, ch);
1426 #if ENABLE_HUSH_INTERACTIVE
1433 /* All callers guarantee this routine will never
1434 * be used right after a newline, so prompting is not needed.
1436 static int file_peek(struct in_str *i)
1439 if (i->p && *i->p) {
1440 if (i->eof_flag && !i->p[1])
1443 /* note: ch is never NUL */
1445 do ch = fgetc(i->file); while (ch == '\0');
1446 i->eof_flag = (ch == EOF);
1447 i->peek_buf[0] = ch;
1448 i->peek_buf[1] = '\0';
1450 debug_printf("file_peek: got '%c' %d\n", ch, ch);
1454 static void setup_file_in_str(struct in_str *i, FILE *f)
1456 i->peek = file_peek;
1458 #if ENABLE_HUSH_INTERACTIVE
1460 i->promptmode = 0; /* PS1 */
1466 static void setup_string_in_str(struct in_str *i, const char *s)
1468 i->peek = static_peek;
1469 i->get = static_get;
1470 #if ENABLE_HUSH_INTERACTIVE
1472 i->promptmode = 0; /* PS1 */
1482 #define B_CHUNK (32 * sizeof(char*))
1484 static void o_reset_to_empty_unquoted(o_string *o)
1492 static void o_free(o_string *o)
1495 memset(o, 0, sizeof(*o));
1498 static ALWAYS_INLINE void o_free_unsafe(o_string *o)
1503 static void o_grow_by(o_string *o, int len)
1505 if (o->length + len > o->maxlen) {
1506 o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
1507 o->data = xrealloc(o->data, 1 + o->maxlen);
1511 static void o_addchr(o_string *o, int ch)
1513 debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
1515 o->data[o->length] = ch;
1517 o->data[o->length] = '\0';
1520 static void o_addblock(o_string *o, const char *str, int len)
1523 memcpy(&o->data[o->length], str, len);
1525 o->data[o->length] = '\0';
1529 static void o_addstr(o_string *o, const char *str)
1531 o_addblock(o, str, strlen(str));
1533 static void nommu_addchr(o_string *o, int ch)
1539 #define nommu_addchr(o, str) ((void)0)
1542 static void o_addstr_with_NUL(o_string *o, const char *str)
1544 o_addblock(o, str, strlen(str) + 1);
1547 static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
1552 && (*str != '*' && *str != '?' && *str != '[')
1560 /* My analysis of quoting semantics tells me that state information
1561 * is associated with a destination, not a source.
1563 static void o_addqchr(o_string *o, int ch)
1566 char *found = strchr("*?[\\", ch);
1571 o->data[o->length] = '\\';
1574 o->data[o->length] = ch;
1576 o->data[o->length] = '\0';
1579 static void o_addQchr(o_string *o, int ch)
1582 if (o->o_escape && strchr("*?[\\", ch)) {
1584 o->data[o->length] = '\\';
1588 o->data[o->length] = ch;
1590 o->data[o->length] = '\0';
1593 static void o_addQstr(o_string *o, const char *str, int len)
1596 o_addblock(o, str, len);
1602 int ordinary_cnt = strcspn(str, "*?[\\");
1603 if (ordinary_cnt > len) /* paranoia */
1605 o_addblock(o, str, ordinary_cnt);
1606 if (ordinary_cnt == len)
1608 str += ordinary_cnt;
1609 len -= ordinary_cnt + 1; /* we are processing + 1 char below */
1613 if (ch) { /* it is necessarily one of "*?[\\" */
1615 o->data[o->length] = '\\';
1619 o->data[o->length] = ch;
1621 o->data[o->length] = '\0';
1625 /* A special kind of o_string for $VAR and `cmd` expansion.
1626 * It contains char* list[] at the beginning, which is grown in 16 element
1627 * increments. Actual string data starts at the next multiple of 16 * (char*).
1628 * list[i] contains an INDEX (int!) into this string data.
1629 * It means that if list[] needs to grow, data needs to be moved higher up
1630 * but list[i]'s need not be modified.
1631 * NB: remembering how many list[i]'s you have there is crucial.
1632 * o_finalize_list() operation post-processes this structure - calculates
1633 * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
1635 #if DEBUG_EXPAND || DEBUG_GLOB
1636 static void debug_print_list(const char *prefix, o_string *o, int n)
1638 char **list = (char**)o->data;
1639 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1643 fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n",
1644 prefix, list, n, string_start, o->length, o->maxlen);
1647 fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i],
1648 o->data + (int)list[i] + string_start,
1649 o->data + (int)list[i] + string_start);
1653 const char *p = o->data + (int)list[n - 1] + string_start;
1655 fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
1659 #define debug_print_list(prefix, o, n) ((void)0)
1662 /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
1663 * in list[n] so that it points past last stored byte so far.
1664 * It returns n+1. */
1665 static int o_save_ptr_helper(o_string *o, int n)
1667 char **list = (char**)o->data;
1671 if (!o->has_empty_slot) {
1672 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1673 string_len = o->length - string_start;
1674 if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
1675 debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
1676 /* list[n] points to string_start, make space for 16 more pointers */
1677 o->maxlen += 0x10 * sizeof(list[0]);
1678 o->data = xrealloc(o->data, o->maxlen + 1);
1679 list = (char**)o->data;
1680 memmove(list + n + 0x10, list + n, string_len);
1681 o->length += 0x10 * sizeof(list[0]);
1683 debug_printf_list("list[%d]=%d string_start=%d\n",
1684 n, string_len, string_start);
1687 /* We have empty slot at list[n], reuse without growth */
1688 string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
1689 string_len = o->length - string_start;
1690 debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n",
1691 n, string_len, string_start);
1692 o->has_empty_slot = 0;
1694 list[n] = (char*)(ptrdiff_t)string_len;
1698 /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
1699 static int o_get_last_ptr(o_string *o, int n)
1701 char **list = (char**)o->data;
1702 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1704 return ((int)(ptrdiff_t)list[n-1]) + string_start;
1707 /* o_glob performs globbing on last list[], saving each result
1708 * as a new list[]. */
1709 static int o_glob(o_string *o, int n)
1715 debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
1717 return o_save_ptr_helper(o, n);
1718 pattern = o->data + o_get_last_ptr(o, n);
1719 debug_printf_glob("glob pattern '%s'\n", pattern);
1720 if (!glob_needed(pattern)) {
1722 o->length = unbackslash(pattern) - o->data;
1723 debug_printf_glob("glob pattern '%s' is literal\n", pattern);
1724 return o_save_ptr_helper(o, n);
1727 memset(&globdata, 0, sizeof(globdata));
1728 gr = glob(pattern, 0, NULL, &globdata);
1729 debug_printf_glob("glob('%s'):%d\n", pattern, gr);
1730 if (gr == GLOB_NOSPACE)
1731 bb_error_msg_and_die("out of memory during glob");
1732 if (gr == GLOB_NOMATCH) {
1733 globfree(&globdata);
1736 if (gr != 0) { /* GLOB_ABORTED ? */
1737 //TODO: testcase for bad glob pattern behavior
1738 bb_error_msg("glob(3) error %d on '%s'", gr, pattern);
1740 if (globdata.gl_pathv && globdata.gl_pathv[0]) {
1741 char **argv = globdata.gl_pathv;
1742 o->length = pattern - o->data; /* "forget" pattern */
1744 o_addstr_with_NUL(o, *argv);
1745 n = o_save_ptr_helper(o, n);
1751 globfree(&globdata);
1753 debug_print_list("o_glob returning", o, n);
1757 /* If o->o_glob == 1, glob the string so far remembered.
1758 * Otherwise, just finish current list[] and start new */
1759 static int o_save_ptr(o_string *o, int n)
1761 if (o->o_glob) { /* if globbing is requested */
1762 /* If o->has_empty_slot, list[n] was already globbed
1763 * (if it was requested back then when it was filled)
1764 * so don't do that again! */
1765 if (!o->has_empty_slot)
1766 return o_glob(o, n); /* o_save_ptr_helper is inside */
1768 return o_save_ptr_helper(o, n);
1771 /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
1772 static char **o_finalize_list(o_string *o, int n)
1777 n = o_save_ptr(o, n); /* force growth for list[n] if necessary */
1779 debug_print_list("finalized", o, n);
1780 debug_printf_expand("finalized n:%d\n", n);
1781 list = (char**)o->data;
1782 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1786 list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start;
1792 /* Expansion can recurse */
1793 #if ENABLE_HUSH_TICK
1794 static int process_command_subs(o_string *dest, const char *s);
1796 static char *expand_string_to_string(const char *str);
1798 #define parse_stream_dquoted(as_string, dest, input, dquote_end) \
1799 parse_stream_dquoted(dest, input, dquote_end)
1801 static int parse_stream_dquoted(o_string *as_string,
1803 struct in_str *input,
1806 /* expand_strvec_to_strvec() takes a list of strings, expands
1807 * all variable references within and returns a pointer to
1808 * a list of expanded strings, possibly with larger number
1809 * of strings. (Think VAR="a b"; echo $VAR).
1810 * This new list is allocated as a single malloc block.
1811 * NULL-terminated list of char* pointers is at the beginning of it,
1812 * followed by strings themself.
1813 * Caller can deallocate entire list by single free(list). */
1815 /* Store given string, finalizing the word and starting new one whenever
1816 * we encounter IFS char(s). This is used for expanding variable values.
1817 * End-of-string does NOT finalize word: think about 'echo -$VAR-' */
1818 static int expand_on_ifs(o_string *output, int n, const char *str)
1821 int word_len = strcspn(str, G.ifs);
1823 if (output->o_escape || !output->o_glob)
1824 o_addQstr(output, str, word_len);
1825 else /* protect backslashes against globbing up :) */
1826 o_addblock_duplicate_backslash(output, str, word_len);
1829 if (!*str) /* EOL - do not finalize word */
1831 o_addchr(output, '\0');
1832 debug_print_list("expand_on_ifs", output, n);
1833 n = o_save_ptr(output, n);
1834 str += strspn(str, G.ifs); /* skip ifs chars */
1836 debug_print_list("expand_on_ifs[1]", output, n);
1840 /* Helper to expand $((...)) and heredoc body. These act as if
1841 * they are in double quotes, with the exception that they are not :).
1842 * Just the rules are similar: "expand only $var and `cmd`"
1844 * Returns malloced string.
1845 * As an optimization, we return NULL if expansion is not needed.
1847 static char *expand_pseudo_dquoted(const char *str)
1850 struct in_str input;
1851 o_string dest = NULL_O_STRING;
1853 if (strchr(str, '$') == NULL
1854 #if ENABLE_HUSH_TICK
1855 && strchr(str, '`') == NULL
1861 /* We need to expand. Example:
1862 * echo $(($a + `echo 1`)) $((1 + $((2)) ))
1864 setup_string_in_str(&input, str);
1865 parse_stream_dquoted(NULL, &dest, &input, EOF);
1866 //bb_error_msg("'%s' -> '%s'", str, dest.data);
1867 exp_str = expand_string_to_string(dest.data);
1868 //bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
1869 o_free_unsafe(&dest);
1873 /* Expand all variable references in given string, adding words to list[]
1874 * at n, n+1,... positions. Return updated n (so that list[n] is next one
1875 * to be filled). This routine is extremely tricky: has to deal with
1876 * variables/parameters with whitespace, $* and $@, and constructs like
1877 * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
1878 static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
1880 /* or_mask is either 0 (normal case) or 0x80
1881 * (expansion of right-hand side of assignment == 1-element expand.
1882 * It will also do no globbing, and thus we must not backslash-quote!) */
1884 char first_ch, ored_ch;
1892 debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
1893 debug_print_list("expand_vars_to_list", output, n);
1894 n = o_save_ptr(output, n);
1895 debug_print_list("expand_vars_to_list[0]", output, n);
1897 while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
1898 #if ENABLE_HUSH_TICK
1899 o_string subst_result = NULL_O_STRING;
1901 #if ENABLE_SH_MATH_SUPPORT
1902 char arith_buf[sizeof(arith_t)*3 + 2];
1904 o_addblock(output, arg, p - arg);
1905 debug_print_list("expand_vars_to_list[1]", output, n);
1907 p = strchr(p, SPECIAL_VAR_SYMBOL);
1909 first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
1910 /* "$@" is special. Even if quoted, it can still
1911 * expand to nothing (not even an empty string) */
1912 if ((first_ch & 0x7f) != '@')
1913 ored_ch |= first_ch;
1916 switch (first_ch & 0x7f) {
1917 /* Highest bit in first_ch indicates that var is double-quoted */
1919 val = utoa(G.root_pid);
1921 case '!': /* bg pid */
1922 val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)"";
1924 case '?': /* exitcode */
1925 val = utoa(G.last_exitcode);
1927 case '#': /* argc */
1928 if (arg[1] != SPECIAL_VAR_SYMBOL)
1929 /* actually, it's a ${#var} */
1931 val = utoa(G.global_argc ? G.global_argc-1 : 0);
1936 if (!G.global_argv[i])
1938 ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
1939 if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
1940 smallint sv = output->o_escape;
1941 /* unquoted var's contents should be globbed, so don't escape */
1942 output->o_escape = 0;
1943 while (G.global_argv[i]) {
1944 n = expand_on_ifs(output, n, G.global_argv[i]);
1945 debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
1946 if (G.global_argv[i++][0] && G.global_argv[i]) {
1947 /* this argv[] is not empty and not last:
1948 * put terminating NUL, start new word */
1949 o_addchr(output, '\0');
1950 debug_print_list("expand_vars_to_list[2]", output, n);
1951 n = o_save_ptr(output, n);
1952 debug_print_list("expand_vars_to_list[3]", output, n);
1955 output->o_escape = sv;
1957 /* If or_mask is nonzero, we handle assignment 'a=....$@.....'
1958 * and in this case should treat it like '$*' - see 'else...' below */
1959 if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */
1961 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1962 if (++i >= G.global_argc)
1964 o_addchr(output, '\0');
1965 debug_print_list("expand_vars_to_list[4]", output, n);
1966 n = o_save_ptr(output, n);
1968 } else { /* quoted $*: add as one word */
1970 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1971 if (!G.global_argv[++i])
1974 o_addchr(output, G.ifs[0]);
1978 case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
1979 /* "Empty variable", used to make "" etc to not disappear */
1983 #if ENABLE_HUSH_TICK
1984 case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
1987 //TODO: can we just stuff it into "output" directly?
1988 debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
1989 process_command_subs(&subst_result, arg);
1990 debug_printf_subst("SUBST RES '%s'\n", subst_result.data);
1991 val = subst_result.data;
1994 #if ENABLE_SH_MATH_SUPPORT
1995 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
1996 arith_eval_hooks_t hooks;
2001 arg++; /* skip '+' */
2002 *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
2003 debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
2005 exp_str = expand_pseudo_dquoted(arg);
2006 hooks.lookupvar = get_local_var_value;
2007 hooks.setvar = arith_set_local_var;
2008 hooks.endofname = endofname;
2009 res = arith(exp_str ? exp_str : arg, &errcode, &hooks);
2013 const char *msg = "error in arithmetic";
2016 msg = "exponent less than 0";
2019 msg = "divide by 0";
2022 msg = "expression recursion loop detected";
2027 debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
2028 sprintf(arith_buf, arith_t_fmt, res);
2033 default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
2035 bool exp_len = false;
2036 bool exp_null = false;
2038 char exp_save = exp_save; /* for compiler */
2039 char exp_op = exp_op; /* for compiler */
2040 char *exp_word = exp_word; /* for compiler */
2044 arg[0] = first_ch & 0x7f;
2046 /* prepare for expansions */
2047 if (var[0] == '#') {
2048 /* handle length expansion ${#var} */
2052 /* maybe handle parameter expansion */
2053 exp_off = strcspn(var, ":-=+?%#");
2057 exp_save = var[exp_off];
2058 exp_null = exp_save == ':';
2059 exp_word = var + exp_off;
2062 exp_op = *exp_word++;
2063 var[exp_off] = '\0';
2067 /* lookup the variable in question */
2068 if (isdigit(var[0])) {
2069 /* handle_dollar() should have vetted var for us */
2071 if (i < G.global_argc)
2072 val = G.global_argv[i];
2073 /* else val remains NULL: $N with too big N */
2075 val = get_local_var_value(var);
2077 /* handle any expansions */
2079 debug_printf_expand("expand: length of '%s' = ", val);
2080 val = utoa(val ? strlen(val) : 0);
2081 debug_printf_expand("%s\n", val);
2082 } else if (exp_off) {
2083 if (exp_op == '%' || exp_op == '#') {
2085 /* we need to do a pattern match */
2088 scan_t scan = pick_scan(exp_op, *exp_word, &zero);
2089 if (exp_op == *exp_word) /* ## or %% */
2091 val = dyn_val = xstrdup(val);
2092 loc = scan(dyn_val, exp_word, zero);
2099 /* we need to do an expansion */
2100 int exp_test = (!val || (exp_null && !val[0]));
2102 exp_test = !exp_test;
2103 debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
2104 exp_null ? "true" : "false", exp_test);
2106 if (exp_op == '?') {
2107 //TODO: how interactive bash aborts expansion mid-command?
2108 /* ${var?[error_msg_if_unset]} */
2109 /* ${var:?[error_msg_if_unset_or_null]} */
2110 /* mimic bash message */
2111 die_if_script("%s: %s",
2113 exp_word[0] ? exp_word : "parameter null or not set"
2119 if (exp_op == '=') {
2120 /* ${var=[word]} or ${var:=[word]} */
2121 if (isdigit(var[0]) || var[0] == '#') {
2122 /* mimic bash message */
2123 die_if_script("$%s: cannot assign in this way", var);
2126 char *new_var = xasprintf("%s=%s", var, val);
2127 set_local_var(new_var, -1, 0);
2133 var[exp_off] = exp_save;
2137 #if ENABLE_HUSH_TICK
2140 if (!(first_ch & 0x80)) { /* unquoted $VAR */
2141 debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape);
2143 /* unquoted var's contents should be globbed, so don't escape */
2144 smallint sv = output->o_escape;
2145 output->o_escape = 0;
2146 n = expand_on_ifs(output, n, val);
2148 output->o_escape = sv;
2150 } else { /* quoted $VAR, val will be appended below */
2151 debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape);
2154 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
2156 o_addQstr(output, val, strlen(val));
2160 /* Do the check to avoid writing to a const string */
2161 if (*p != SPECIAL_VAR_SYMBOL)
2162 *p = SPECIAL_VAR_SYMBOL;
2164 #if ENABLE_HUSH_TICK
2165 o_free(&subst_result);
2168 } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
2171 debug_print_list("expand_vars_to_list[a]", output, n);
2172 /* this part is literal, and it was already pre-quoted
2173 * if needed (much earlier), do not use o_addQstr here! */
2174 o_addstr_with_NUL(output, arg);
2175 debug_print_list("expand_vars_to_list[b]", output, n);
2176 } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
2177 && !(ored_ch & 0x80) /* and all vars were not quoted. */
2180 /* allow to reuse list[n] later without re-growth */
2181 output->has_empty_slot = 1;
2183 o_addchr(output, '\0');
2188 static char **expand_variables(char **argv, int or_mask)
2193 o_string output = NULL_O_STRING;
2195 if (or_mask & 0x100) {
2196 output.o_escape = 1; /* protect against globbing for "$var" */
2197 /* (unquoted $var will temporarily switch it off) */
2204 n = expand_vars_to_list(&output, n, *v, (char)or_mask);
2207 debug_print_list("expand_variables", &output, n);
2209 /* output.data (malloced in one block) gets returned in "list" */
2210 list = o_finalize_list(&output, n);
2211 debug_print_strings("expand_variables[1]", list);
2215 static char **expand_strvec_to_strvec(char **argv)
2217 return expand_variables(argv, 0x100);
2220 /* Used for expansion of right hand of assignments */
2221 /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs
2223 static char *expand_string_to_string(const char *str)
2225 char *argv[2], **list;
2227 argv[0] = (char*)str;
2229 list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */
2231 if (!list[0] || list[1])
2232 bb_error_msg_and_die("BUG in varexp2");
2233 /* actually, just move string 2*sizeof(char*) bytes back */
2234 overlapping_strcpy((char*)list, list[0]);
2235 debug_printf_expand("string_to_string='%s'\n", (char*)list);
2239 /* Used for "eval" builtin */
2240 static char* expand_strvec_to_string(char **argv)
2244 list = expand_variables(argv, 0x80);
2245 /* Convert all NULs to spaces */
2250 if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
2251 bb_error_msg_and_die("BUG in varexp3");
2252 list[n][-1] = ' '; /* TODO: or to G.ifs[0]? */
2256 overlapping_strcpy((char*)list, list[0]);
2257 debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
2261 static char **expand_assignments(char **argv, int count)
2265 /* Expand assignments into one string each */
2266 for (i = 0; i < count; i++) {
2267 p = add_string_to_strings(p, expand_string_to_string(argv[i]));
2275 void re_execute_shell(char ***to_free, const char *s, char *argv0, char **argv);
2277 static void reset_traps_to_defaults(void)
2280 JOBSIGS = (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
2284 if (!G.traps && !(G.non_DFL_mask & JOBSIGS))
2287 /* This function is always called in a child shell.
2288 * Child shells are not interactive.
2289 * SIGTTIN/SIGTTOU/SIGTSTP should not have special handling.
2290 * Testcase: (while :; do :; done) + ^Z should background.
2292 G.non_DFL_mask &= ~JOBSIGS;
2293 sigdelset(&G.blocked_set, SIGTTIN);
2294 sigdelset(&G.blocked_set, SIGTTOU);
2295 sigdelset(&G.blocked_set, SIGTSTP);
2297 if (G.traps) for (sig = 0; sig < NSIG; sig++) {
2298 if (!G.traps[sig]) {
2302 G.traps[sig] = NULL;
2303 /* There is no signal for 0 (EXIT) */
2306 /* there was a trap handler, we are removing it
2307 * (if sig has non-DFL handling,
2308 * we don't need to do anything) */
2309 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
2311 sigdelset(&G.blocked_set, sig);
2313 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
2318 static void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char **g_argv) NORETURN;
2319 static void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char **g_argv)
2321 char param_buf[sizeof("-$%x:%x:%x:%x") + sizeof(unsigned) * 4];
2322 char *heredoc_argv[4];
2323 struct variable *cur;
2324 #if ENABLE_HUSH_FUNCTIONS
2325 struct function *funcp;
2330 if (!g_argv0) { /* heredoc */
2331 argv = heredoc_argv;
2332 argv[0] = (char *) G.argv0_for_re_execing;
2333 argv[1] = (char *) "-<";
2334 argv[2] = (char *) s;
2336 pp = &argv[3]; /* used as pointer to empty environment */
2340 sprintf(param_buf, "-$%x:%x:%x" USE_HUSH_LOOPS(":%x")
2341 , (unsigned) G.root_pid
2342 , (unsigned) G.last_bg_pid
2343 , (unsigned) G.last_exitcode
2344 USE_HUSH_LOOPS(, G.depth_of_loop)
2346 /* 1:hush 2:-$<pid>:<pid>:<exitcode>:<depth> <vars...> <funcs...>
2347 * 3:-c 4:<cmd> 5:<arg0> <argN...> 6:NULL
2350 for (cur = G.top_var; cur; cur = cur->next) {
2351 if (!cur->flg_export || cur->flg_read_only)
2354 #if ENABLE_HUSH_FUNCTIONS
2355 for (funcp = G.top_func; funcp; funcp = funcp->next)
2361 *to_free = argv = pp = xzalloc(sizeof(argv[0]) * cnt);
2362 *pp++ = (char *) G.argv0_for_re_execing;
2364 for (cur = G.top_var; cur; cur = cur->next) {
2365 if (cur->varstr == hush_version_str)
2367 if (cur->flg_read_only) {
2368 *pp++ = (char *) "-R";
2369 *pp++ = cur->varstr;
2370 } else if (!cur->flg_export) {
2371 *pp++ = (char *) "-V";
2372 *pp++ = cur->varstr;
2375 #if ENABLE_HUSH_FUNCTIONS
2376 for (funcp = G.top_func; funcp; funcp = funcp->next) {
2377 *pp++ = (char *) "-F";
2378 *pp++ = funcp->name;
2379 *pp++ = funcp->body_as_string;
2382 /* We can pass activated traps here. Say, -Tnn:trap_string
2384 * However, POSIX says that subshells reset signals with traps
2386 * I tested bash-3.2 and it not only does that with true subshells
2387 * of the form ( list ), but with any forked children shells.
2388 * I set trap "echo W" WINCH; and then tried:
2390 * { echo 1; sleep 20; echo 2; } &
2391 * while true; do echo 1; sleep 20; echo 2; break; done &
2392 * true | { echo 1; sleep 20; echo 2; } | cat
2394 * In all these cases sending SIGWINCH to the child shell
2395 * did not run the trap. If I add trap "echo V" WINCH;
2396 * _inside_ group (just before echo 1), it works.
2398 * I conclude it means we don't need to pass active traps here.
2399 * exec syscall below resets them to SIG_DFL for us.
2401 *pp++ = (char *) "-c";
2406 /* *pp = NULL; - is already there */
2410 debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
2411 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2412 execve(bb_busybox_exec_path, argv, pp);
2413 /* Fallback. Useful for init=/bin/hush usage etc */
2414 if (argv[0][0] == '/')
2415 execve(argv[0], argv, pp);
2416 xfunc_error_retval = 127;
2417 bb_error_msg_and_die("can't re-execute the shell");
2419 #endif /* !BB_MMU */
2422 static void setup_heredoc(struct redir_struct *redir)
2424 struct fd_pair pair;
2427 /* the _body_ of heredoc (misleading field name) */
2428 const char *heredoc = redir->rd_filename;
2435 if (!(redir->rd_dup & HEREDOC_QUOTED)) {
2436 expanded = expand_pseudo_dquoted(heredoc);
2440 len = strlen(heredoc);
2442 close(redir->rd_fd); /* often saves dup2+close in xmove_fd */
2444 xmove_fd(pair.rd, redir->rd_fd);
2446 /* Try writing without forking. Newer kernels have
2447 * dynamically growing pipes. Must use non-blocking write! */
2450 written = write(pair.wr, heredoc, len);
2461 ndelay_off(pair.wr);
2463 /* Okay, pipe buffer was not big enough */
2464 /* Note: we must not create a stray child (bastard? :)
2465 * for the unsuspecting parent process. Child creates a grandchild
2466 * and exits before parent execs the process which consumes heredoc
2467 * (that exec happens after we return from this function) */
2473 bb_perror_msg_and_die("vfork");
2476 disable_restore_tty_pgrp_on_exit();
2477 pid = BB_MMU ? fork() : vfork();
2479 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
2483 close(redir->rd_fd); /* read side of the pipe */
2485 full_write(pair.wr, heredoc, len); /* may loop or block */
2488 /* Delegate blocking writes to another process */
2489 xmove_fd(pair.wr, STDOUT_FILENO);
2490 re_execute_shell(&to_free, heredoc, NULL, NULL);
2494 enable_restore_tty_pgrp_on_exit();
2500 wait(NULL); /* wait till child has died */
2503 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
2504 * and stderr if they are redirected. */
2505 static int setup_redirects(struct command *prog, int squirrel[])
2508 struct redir_struct *redir;
2510 for (redir = prog->redirects; redir; redir = redir->next) {
2511 if (redir->rd_type == REDIRECT_HEREDOC2) {
2512 /* rd_fd<<HERE case */
2513 if (squirrel && redir->rd_fd < 3) {
2514 squirrel[redir->rd_fd] = dup(redir->rd_fd);
2516 /* for REDIRECT_HEREDOC2, rd_filename holds _contents_
2518 debug_printf_parse("set heredoc '%s'\n",
2519 redir->rd_filename);
2520 setup_heredoc(redir);
2524 if (redir->rd_dup == REDIRFD_TO_FILE) {
2525 /* rd_fd<*>file case (<*> is <,>,>>,<>) */
2527 if (redir->rd_filename == NULL) {
2528 /* Something went wrong in the parse.
2529 * Pretend it didn't happen */
2530 bb_error_msg("bug in redirect parse");
2533 mode = redir_table[redir->rd_type].mode;
2534 p = expand_string_to_string(redir->rd_filename);
2535 openfd = open_or_warn(p, mode);
2538 /* this could get lost if stderr has been redirected, but
2539 * bash and ash both lose it as well (though zsh doesn't!) */
2540 //what the above comment tries to say?
2544 /* rd_fd<*>rd_dup or rd_fd<*>- cases */
2545 openfd = redir->rd_dup;
2548 if (openfd != redir->rd_fd) {
2549 if (squirrel && redir->rd_fd < 3) {
2550 squirrel[redir->rd_fd] = dup(redir->rd_fd);
2552 if (openfd == REDIRFD_CLOSE) {
2553 /* "n>-" means "close me" */
2554 close(redir->rd_fd);
2556 xdup2(openfd, redir->rd_fd);
2557 if (redir->rd_dup == REDIRFD_TO_FILE)
2565 static void restore_redirects(int squirrel[])
2568 for (i = 0; i < 3; i++) {
2571 /* We simply die on error */
2578 static void free_pipe_list(struct pipe *head);
2580 /* Return code is the exit status of the pipe */
2581 static void free_pipe(struct pipe *pi)
2584 struct command *command;
2585 struct redir_struct *r, *rnext;
2588 if (pi->stopped_cmds > 0) /* why? */
2590 debug_printf_clean("run pipe: (pid %d)\n", getpid());
2591 for (i = 0; i < pi->num_cmds; i++) {
2592 command = &pi->cmds[i];
2593 debug_printf_clean(" command %d:\n", i);
2594 if (command->argv) {
2595 for (a = 0, p = command->argv; *p; a++, p++) {
2596 debug_printf_clean(" argv[%d] = %s\n", a, *p);
2598 free_strings(command->argv);
2599 command->argv = NULL;
2601 /* not "else if": on syntax error, we may have both! */
2602 if (command->group) {
2603 debug_printf_clean(" begin group (grp_type:%d)\n",
2605 free_pipe_list(command->group);
2606 debug_printf_clean(" end group\n");
2607 command->group = NULL;
2609 /* else is crucial here.
2610 * If group != NULL, child_func is meaningless */
2611 #if ENABLE_HUSH_FUNCTIONS
2612 else if (command->child_func) {
2613 debug_printf_exec("cmd %p releases child func at %p\n", command, command->child_func);
2614 command->child_func->parent_cmd = NULL;
2618 free(command->group_as_string);
2619 command->group_as_string = NULL;
2621 for (r = command->redirects; r; r = rnext) {
2622 debug_printf_clean(" redirect %d%s",
2623 r->rd_fd, redir_table[r->rd_type].descrip);
2624 /* guard against the case >$FOO, where foo is unset or blank */
2625 if (r->rd_filename) {
2626 debug_printf_clean(" fname:'%s'\n", r->rd_filename);
2627 free(r->rd_filename);
2628 r->rd_filename = NULL;
2630 debug_printf_clean(" rd_dup:%d\n", r->rd_dup);
2634 command->redirects = NULL;
2636 free(pi->cmds); /* children are an array, they get freed all at once */
2644 static void free_pipe_list(struct pipe *head)
2646 struct pipe *pi, *next;
2648 for (pi = head; pi; pi = next) {
2650 debug_printf_clean(" pipe reserved word %d\n", pi->res_word);
2653 debug_printf_clean("pipe followup code %d\n", pi->followup);
2655 /*pi->next = NULL;*/
2661 static int run_list(struct pipe *pi);
2663 #define parse_stream(pstring, input, end_trigger) \
2664 parse_stream(input, end_trigger)
2666 static struct pipe *parse_stream(char **pstring,
2667 struct in_str *input,
2669 static void parse_and_run_string(const char *s);
2672 static const struct built_in_command* find_builtin(const char *name)
2674 const struct built_in_command *x;
2675 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2676 if (strcmp(name, x->cmd) != 0)
2678 debug_printf_exec("found builtin '%s'\n", name);
2684 #if ENABLE_HUSH_FUNCTIONS
2685 static const struct function *find_function(const char *name)
2687 const struct function *funcp = G.top_func;
2689 if (strcmp(name, funcp->name) == 0) {
2692 funcp = funcp->next;
2694 debug_printf_exec("found function '%s'\n", name);
2698 /* Note: takes ownership on name ptr */
2699 static struct function *new_function(char *name)
2701 struct function *funcp;
2702 struct function **funcpp = &G.top_func;
2704 while ((funcp = *funcpp) != NULL) {
2705 struct command *cmd;
2707 if (strcmp(funcp->name, name) != 0) {
2708 funcpp = &funcp->next;
2712 cmd = funcp->parent_cmd;
2713 debug_printf_exec("func %p parent_cmd %p\n", funcp, cmd);
2715 debug_printf_exec("freeing & replacing function '%s'\n", funcp->name);
2717 /* Note: if !funcp->body, do not free body_as_string!
2718 * This is a special case of "-F name body" function:
2719 * body_as_string was not malloced! */
2721 free_pipe_list(funcp->body);
2723 free(funcp->body_as_string);
2727 debug_printf_exec("reinserting in tree & replacing function '%s'\n", funcp->name);
2728 cmd->argv[0] = funcp->name;
2729 cmd->group = funcp->body;
2731 cmd->group_as_string = funcp->body_as_string;
2736 debug_printf_exec("remembering new function '%s'\n", command->argv[0]);
2737 funcp = *funcpp = xzalloc(sizeof(*funcp));
2738 /*funcp->next = NULL;*/
2745 #define exec_function(nommu_save, funcp, argv) \
2746 exec_function(funcp, argv)
2748 static void exec_function(nommu_save_t *nommu_save,
2749 const struct function *funcp,
2750 char **argv) NORETURN;
2751 static void exec_function(nommu_save_t *nommu_save,
2752 const struct function *funcp,
2758 argv[0] = G.global_argv[0];
2759 G.global_argv = argv;
2763 /* On MMU, funcp->body is always non-NULL */
2764 n = run_list(funcp->body);
2768 re_execute_shell(&nommu_save->argv_from_re_execing,
2769 funcp->body_as_string,
2775 static int run_function(const struct function *funcp, char **argv)
2780 smallint sv_g_malloced;
2785 sv_g_malloced = G.global_args_malloced;
2786 sv_g_argc = G.global_argc;
2787 sv_g_argv = G.global_argv;
2794 argv[0] = G.global_argv[0]; /* retain $0 */
2795 G.global_args_malloced = 0;
2797 G.global_argv = argv;
2799 /* On MMU, funcp->body is always non-NULL */
2802 /* Function defined by -F */
2803 parse_and_run_string(funcp->body_as_string);
2804 n = G.last_exitcode;
2808 n = run_list(funcp->body);
2811 if (G.global_args_malloced) {
2812 /* function ran "set -- arg1 arg2 ..." */
2816 free(G.global_argv);
2820 G.global_args_malloced = sv_g_malloced;
2821 G.global_argc = sv_g_argc;
2822 G.global_argv = sv_g_argv;
2830 #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
2831 pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
2832 #define pseudo_exec(nommu_save, command, argv_expanded) \
2833 pseudo_exec(command, argv_expanded)
2836 /* Called after [v]fork() in run_pipe, or from builtin_exec.
2838 * XXX no exit() here. If you don't exec, use _exit instead.
2839 * The at_exit handlers apparently confuse the calling process,
2840 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
2841 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2842 char **argv, int assignment_cnt,
2843 char **argv_expanded) NORETURN;
2844 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2845 char **argv, int assignment_cnt,
2846 char **argv_expanded)
2850 /* Case when we are here: ... | var=val | ... */
2851 if (!argv[assignment_cnt])
2852 _exit(EXIT_SUCCESS);
2854 new_env = expand_assignments(argv, assignment_cnt);
2856 putenv_all(new_env);
2857 free(new_env); /* optional */
2859 nommu_save->new_env = new_env;
2860 nommu_save->old_env = putenv_all_and_save_old(new_env);
2862 if (argv_expanded) {
2863 argv = argv_expanded;
2865 argv = expand_strvec_to_strvec(argv + assignment_cnt);
2867 nommu_save->argv = argv;
2871 #if ENABLE_FEATURE_SH_STANDALONE || BB_MMU
2872 if (strchr(argv[0], '/') != NULL)
2876 /* On NOMMU, we must never block!
2877 * Example: { sleep 99999 | read line } & echo Ok
2878 * read builtin will block on read syscall, leaving parent blocked
2879 * in vfork. Therefore we can't do this:
2882 /* Check if the command matches any of the builtins.
2883 * Depending on context, this might be redundant. But it's
2884 * easier to waste a few CPU cycles than it is to figure out
2885 * if this is one of those cases.
2889 const struct built_in_command *x = find_builtin(argv[0]);
2891 rcode = x->function(argv);
2897 #if ENABLE_HUSH_FUNCTIONS
2898 /* Check if the command matches any functions */
2900 const struct function *funcp = find_function(argv[0]);
2902 exec_function(nommu_save, funcp, argv);
2907 #if ENABLE_FEATURE_SH_STANDALONE
2908 /* Check if the command matches any busybox applets */
2910 int a = find_applet_by_name(argv[0]);
2912 # if BB_MMU /* see above why on NOMMU it is not allowed */
2913 if (APPLET_IS_NOEXEC(a)) {
2914 debug_printf_exec("running applet '%s'\n", argv[0]);
2915 run_applet_no_and_exit(a, argv);
2918 /* Re-exec ourselves */
2919 debug_printf_exec("re-execing applet '%s'\n", argv[0]);
2920 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2921 execv(bb_busybox_exec_path, argv);
2922 /* If they called chroot or otherwise made the binary no longer
2923 * executable, fall through */
2928 #if ENABLE_FEATURE_SH_STANDALONE || BB_MMU
2931 debug_printf_exec("execing '%s'\n", argv[0]);
2932 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2933 execvp(argv[0], argv);
2934 bb_perror_msg("can't exec '%s'", argv[0]);
2935 _exit(EXIT_FAILURE);
2938 /* Called after [v]fork() in run_pipe
2940 static void pseudo_exec(nommu_save_t *nommu_save,
2941 struct command *command,
2942 char **argv_expanded) NORETURN;
2943 static void pseudo_exec(nommu_save_t *nommu_save,
2944 struct command *command,
2945 char **argv_expanded)
2947 if (command->argv) {
2948 pseudo_exec_argv(nommu_save, command->argv,
2949 command->assignment_cnt, argv_expanded);
2952 if (command->group) {
2953 /* Cases when we are here:
2956 * ... | ( list ) | ...
2957 * ... | { list } | ...
2961 debug_printf_exec("pseudo_exec: run_list\n");
2962 reset_traps_to_defaults();
2963 rcode = run_list(command->group);
2964 /* OK to leak memory by not calling free_pipe_list,
2965 * since this process is about to exit */
2968 re_execute_shell(&nommu_save->argv_from_re_execing,
2969 command->group_as_string,
2975 /* Case when we are here: ... | >file */
2976 debug_printf_exec("pseudo_exec'ed null command\n");
2977 _exit(EXIT_SUCCESS);
2981 static const char *get_cmdtext(struct pipe *pi)
2987 /* This is subtle. ->cmdtext is created only on first backgrounding.
2988 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
2989 * On subsequent bg argv is trashed, but we won't use it */
2992 argv = pi->cmds[0].argv;
2993 if (!argv || !argv[0]) {
2994 pi->cmdtext = xzalloc(1);
2999 do len += strlen(*argv) + 1; while (*++argv);
3000 pi->cmdtext = p = xmalloc(len);
3001 argv = pi->cmds[0].argv;
3003 len = strlen(*argv);
3004 memcpy(p, *argv, len);
3012 static void insert_bg_job(struct pipe *pi)
3014 struct pipe *thejob;
3017 /* Linear search for the ID of the job to use */
3019 for (thejob = G.job_list; thejob; thejob = thejob->next)
3020 if (thejob->jobid >= pi->jobid)
3021 pi->jobid = thejob->jobid + 1;
3023 /* Add thejob to the list of running jobs */
3025 thejob = G.job_list = xmalloc(sizeof(*thejob));
3027 for (thejob = G.job_list; thejob->next; thejob = thejob->next)
3029 thejob->next = xmalloc(sizeof(*thejob));
3030 thejob = thejob->next;
3033 /* Physically copy the struct job */
3034 memcpy(thejob, pi, sizeof(struct pipe));
3035 thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
3036 /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */
3037 for (i = 0; i < pi->num_cmds; i++) {
3038 // TODO: do we really need to have so many fields which are just dead weight
3039 // at execution stage?
3040 thejob->cmds[i].pid = pi->cmds[i].pid;
3041 /* all other fields are not used and stay zero */
3043 thejob->next = NULL;
3044 thejob->cmdtext = xstrdup(get_cmdtext(pi));
3046 /* We don't wait for background thejobs to return -- append it
3047 to the list of backgrounded thejobs and leave it alone */
3048 if (G_interactive_fd)
3049 printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext);
3050 G.last_bg_pid = thejob->cmds[0].pid;
3051 G.last_jobid = thejob->jobid;
3054 static void remove_bg_job(struct pipe *pi)
3056 struct pipe *prev_pipe;
3058 if (pi == G.job_list) {
3059 G.job_list = pi->next;
3061 prev_pipe = G.job_list;
3062 while (prev_pipe->next != pi)
3063 prev_pipe = prev_pipe->next;
3064 prev_pipe->next = pi->next;
3067 G.last_jobid = G.job_list->jobid;
3072 /* Remove a backgrounded job */
3073 static void delete_finished_bg_job(struct pipe *pi)
3076 pi->stopped_cmds = 0;
3082 /* Check to see if any processes have exited -- if they
3083 * have, figure out why and see if a job has completed */
3084 static int checkjobs(struct pipe* fg_pipe)
3094 debug_printf_jobs("checkjobs %p\n", fg_pipe);
3097 // if (G.handled_SIGCHLD == G.count_SIGCHLD)
3098 // /* avoid doing syscall, nothing there anyway */
3101 attributes = WUNTRACED;
3102 if (fg_pipe == NULL)
3103 attributes |= WNOHANG;
3105 /* Do we do this right?
3106 * bash-3.00# sleep 20 | false
3108 * [3]+ Stopped sleep 20 | false
3109 * bash-3.00# echo $?
3110 * 1 <========== bg pipe is not fully done, but exitcode is already known!
3113 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
3114 //are stopped. Testcase: "cat | cat" in a script (not on command line)
3115 // + killall -STOP cat
3122 // i = G.count_SIGCHLD;
3123 childpid = waitpid(-1, &status, attributes);
3124 if (childpid <= 0) {
3125 if (childpid && errno != ECHILD)
3126 bb_perror_msg("waitpid");
3127 // else /* Until next SIGCHLD, waitpid's are useless */
3128 // G.handled_SIGCHLD = i;
3131 dead = WIFEXITED(status) || WIFSIGNALED(status);
3134 if (WIFSTOPPED(status))
3135 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
3136 childpid, WSTOPSIG(status), WEXITSTATUS(status));
3137 if (WIFSIGNALED(status))
3138 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
3139 childpid, WTERMSIG(status), WEXITSTATUS(status));
3140 if (WIFEXITED(status))
3141 debug_printf_jobs("pid %d exited, exitcode %d\n",
3142 childpid, WEXITSTATUS(status));
3144 /* Were we asked to wait for fg pipe? */
3146 for (i = 0; i < fg_pipe->num_cmds; i++) {
3147 debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
3148 if (fg_pipe->cmds[i].pid != childpid)
3150 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
3152 fg_pipe->cmds[i].pid = 0;
3153 fg_pipe->alive_cmds--;
3154 if (i == fg_pipe->num_cmds - 1) {
3155 /* last process gives overall exitstatus */
3156 rcode = WEXITSTATUS(status);
3157 IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
3160 fg_pipe->cmds[i].is_stopped = 1;
3161 fg_pipe->stopped_cmds++;
3163 debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
3164 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
3165 if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) {
3166 /* All processes in fg pipe have exited/stopped */
3168 if (fg_pipe->alive_cmds)
3169 insert_bg_job(fg_pipe);
3173 /* There are still running processes in the fg pipe */
3174 goto wait_more; /* do waitpid again */
3176 /* it wasnt fg_pipe, look for process in bg pipes */
3180 /* We asked to wait for bg or orphaned children */
3181 /* No need to remember exitcode in this case */
3182 for (pi = G.job_list; pi; pi = pi->next) {
3183 for (i = 0; i < pi->num_cmds; i++) {
3184 if (pi->cmds[i].pid == childpid)
3185 goto found_pi_and_prognum;
3188 /* Happens when shell is used as init process (init=/bin/sh) */
3189 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
3190 continue; /* do waitpid again */
3192 found_pi_and_prognum:
3195 pi->cmds[i].pid = 0;
3197 if (!pi->alive_cmds) {
3198 if (G_interactive_fd)
3199 printf(JOB_STATUS_FORMAT, pi->jobid,
3200 "Done", pi->cmdtext);
3201 delete_finished_bg_job(pi);
3205 pi->cmds[i].is_stopped = 1;
3209 } /* while (waitpid succeeds)... */
3215 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
3218 int rcode = checkjobs(fg_pipe);
3219 /* Job finished, move the shell to the foreground */
3220 p = getpgid(0); /* pgid of our process */
3221 debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
3222 tcsetpgrp(G_interactive_fd, p);
3227 /* Start all the jobs, but don't wait for anything to finish.
3230 * Return code is normally -1, when the caller has to wait for children
3231 * to finish to determine the exit status of the pipe. If the pipe
3232 * is a simple builtin command, however, the action is done by the
3233 * time run_pipe returns, and the exit code is provided as the
3236 * Returns -1 only if started some children. IOW: we have to
3237 * mask out retvals of builtins etc with 0xff!
3239 * The only case when we do not need to [v]fork is when the pipe
3240 * is single, non-backgrounded, non-subshell command. Examples:
3241 * cmd ; ... { list } ; ...
3242 * cmd && ... { list } && ...
3243 * cmd || ... { list } || ...
3244 * If it is, then we can run cmd as a builtin, NOFORK [do we do this?],
3245 * or (if SH_STANDALONE) an applet, and we can run the { list }
3246 * with run_list(). If it isn't one of these, we fork and exec cmd.
3248 * Cases when we must fork:
3249 * non-single: cmd | cmd
3250 * backgrounded: cmd & { list } &
3251 * subshell: ( list ) [&]
3253 static int run_pipe(struct pipe *pi)
3255 static const char *const null_ptr = NULL;
3258 int pipefds[2]; /* pipefds[0] is for reading */
3259 struct command *command;
3260 char **argv_expanded;
3263 /* it is not always needed, but we aim to smaller code */
3264 int squirrel[] = { -1, -1, -1 };
3267 debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
3270 USE_HUSH_JOB(pi->pgrp = -1;)
3271 pi->stopped_cmds = 0;
3272 command = &(pi->cmds[0]);
3273 argv_expanded = NULL;
3275 if (pi->num_cmds != 1
3276 || pi->followup == PIPE_BG
3277 || command->grp_type == GRP_SUBSHELL
3284 debug_printf_exec(": group:%p argv:'%s'\n",
3285 command->group, command->argv ? command->argv[0] : "NONE");
3287 if (command->group) {
3288 #if ENABLE_HUSH_FUNCTIONS
3289 if (command->grp_type == GRP_FUNCTION) {
3290 /* "executing" func () { list } */
3291 struct function *funcp;
3293 funcp = new_function(command->argv[0]);
3294 /* funcp->name is already set to argv[0] */
3295 funcp->body = command->group;
3297 funcp->body_as_string = command->group_as_string;
3298 command->group_as_string = NULL;
3300 command->group = NULL;
3301 command->argv[0] = NULL;
3302 debug_printf_exec("cmd %p has child func at %p\n", command, funcp);
3303 funcp->parent_cmd = command;
3304 command->child_func = funcp;
3306 debug_printf_exec("run_pipe: return EXIT_SUCCESS\n");
3308 return EXIT_SUCCESS;
3312 debug_printf("non-subshell group\n");
3313 rcode = 1; /* exitcode if redir failed */
3314 if (setup_redirects(command, squirrel) == 0) {
3315 debug_printf_exec(": run_list\n");
3316 rcode = run_list(command->group) & 0xff;
3318 restore_redirects(squirrel);
3319 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
3321 debug_printf_exec("run_pipe: return %d\n", rcode);
3325 argv = command->argv ? command->argv : (char **) &null_ptr;
3327 const struct built_in_command *x;
3328 #if ENABLE_HUSH_FUNCTIONS
3329 const struct function *funcp;
3333 char **new_env = NULL;
3334 char **old_env = NULL;
3336 if (argv[command->assignment_cnt] == NULL) {
3337 /* Assignments, but no command */
3338 /* Ensure redirects take effect. Try "a=t >file" */
3339 rcode = setup_redirects(command, squirrel);
3340 restore_redirects(squirrel);
3341 /* Set shell variables */
3343 p = expand_string_to_string(*argv);
3344 debug_printf_exec("set shell var:'%s'->'%s'\n",
3346 set_local_var(p, 0, 0);
3349 /* Do we need to flag set_local_var() errors?
3350 * "assignment to readonly var" and "putenv error"
3352 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
3354 debug_printf_exec("run_pipe: return %d\n", rcode);
3358 /* Expand the rest into (possibly) many strings each */
3359 argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
3361 x = find_builtin(argv_expanded[0]);
3362 #if ENABLE_HUSH_FUNCTIONS
3365 funcp = find_function(argv_expanded[0]);
3369 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
3370 debug_printf("exec with redirects only\n");
3371 rcode = setup_redirects(command, NULL);
3372 goto clean_up_and_ret1;
3375 /* XXX setup_redirects acts on file descriptors, not FILEs.
3376 * This is perfect for work that comes after exec().
3377 * Is it really safe for inline use? Experimentally,
3378 * things seem to work with glibc. */
3379 rcode = setup_redirects(command, squirrel);
3381 new_env = expand_assignments(argv, command->assignment_cnt);
3382 old_env = putenv_all_and_save_old(new_env);
3384 debug_printf_exec(": builtin '%s' '%s'...\n",
3385 x->cmd, argv_expanded[1]);
3386 rcode = x->function(argv_expanded) & 0xff;
3388 #if ENABLE_HUSH_FUNCTIONS
3390 debug_printf_exec(": function '%s' '%s'...\n",
3391 funcp->name, argv_expanded[1]);
3392 rcode = run_function(funcp, argv_expanded) & 0xff;
3396 #if ENABLE_FEATURE_SH_STANDALONE
3399 restore_redirects(squirrel);
3400 free_strings_and_unsetenv(new_env, 1);
3401 putenv_all(old_env);
3402 /* Free the pointers, but the strings themselves
3403 * are in environ now, don't use free_strings! */
3406 free(argv_expanded);
3407 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
3409 debug_printf_exec("run_pipe return %d\n", rcode);
3413 #if ENABLE_FEATURE_SH_STANDALONE
3414 i = find_applet_by_name(argv_expanded[0]);
3415 if (i >= 0 && APPLET_IS_NOFORK(i)) {
3416 rcode = setup_redirects(command, squirrel);
3418 new_env = expand_assignments(argv, command->assignment_cnt);
3419 old_env = putenv_all_and_save_old(new_env);
3420 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
3421 argv_expanded[0], argv_expanded[1]);
3422 rcode = run_nofork_applet(i, argv_expanded);
3424 goto clean_up_and_ret;
3427 /* It is neither builtin nor applet. We must fork. */
3431 /* NB: argv_expanded may already be created, and that
3432 * might include `cmd` runs! Do not rerun it! We *must*
3433 * use argv_expanded if it's non-NULL */
3435 /* Going to fork a child per each pipe member */
3439 for (i = 0; i < pi->num_cmds; i++) {
3441 volatile nommu_save_t nommu_save;
3442 nommu_save.new_env = NULL;
3443 nommu_save.old_env = NULL;
3444 nommu_save.argv = NULL;
3445 nommu_save.argv_from_re_execing = NULL;
3447 command = &(pi->cmds[i]);
3448 if (command->argv) {
3449 debug_printf_exec(": pipe member '%s' '%s'...\n",
3450 command->argv[0], command->argv[1]);
3452 debug_printf_exec(": pipe member with no argv\n");
3455 /* pipes are inserted between pairs of commands */
3458 if ((i + 1) < pi->num_cmds)
3461 command->pid = BB_MMU ? fork() : vfork();
3462 if (!command->pid) { /* child */
3464 disable_restore_tty_pgrp_on_exit();
3466 /* Every child adds itself to new process group
3467 * with pgid == pid_of_first_child_in_pipe */
3468 if (G.run_list_level == 1 && G_interactive_fd) {
3471 if (pgrp < 0) /* true for 1st process only */
3473 if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
3474 /* We do it in *every* child, not just first,
3476 tcsetpgrp(G_interactive_fd, pgrp);
3480 xmove_fd(nextin, 0);
3481 xmove_fd(pipefds[1], 1); /* write end */
3483 close(pipefds[0]); /* read end */
3484 /* Like bash, explicit redirects override pipes,
3485 * and the pipe fd is available for dup'ing. */
3486 if (setup_redirects(command, NULL))
3489 /* Restore default handlers just prior to exec */
3490 /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
3492 /* Stores to nommu_save list of env vars putenv'ed
3493 * (NOMMU, on MMU we don't need that) */
3494 /* cast away volatility... */
3495 pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
3496 /* pseudo_exec() does not return */
3499 /* parent or error */
3500 enable_restore_tty_pgrp_on_exit();
3502 /* Clean up after vforked child */
3503 free(nommu_save.argv);
3504 free(nommu_save.argv_from_re_execing);
3505 free_strings_and_unsetenv(nommu_save.new_env, 1);
3506 putenv_all(nommu_save.old_env);
3507 /* Free the pointers, but the strings themselves
3508 * are in environ now, don't use free_strings! */
3509 free(nommu_save.old_env);
3511 free(argv_expanded);
3512 argv_expanded = NULL;
3513 if (command->pid < 0) { /* [v]fork failed */
3514 /* Clearly indicate, was it fork or vfork */
3515 bb_perror_msg(BB_MMU ? "fork" : "vfork");
3519 /* Second and next children need to know pid of first one */
3521 pi->pgrp = command->pid;
3527 if ((i + 1) < pi->num_cmds)
3528 close(pipefds[1]); /* write end */
3529 /* Pass read (output) pipe end to next iteration */
3530 nextin = pipefds[0];
3533 if (!pi->alive_cmds) {
3535 debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
3540 debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
3544 #ifndef debug_print_tree
3545 static void debug_print_tree(struct pipe *pi, int lvl)
3547 static const char *const PIPE[] = {
3553 static const char *RES[] = {
3554 [RES_NONE ] = "NONE" ,
3557 [RES_THEN ] = "THEN" ,
3558 [RES_ELIF ] = "ELIF" ,
3559 [RES_ELSE ] = "ELSE" ,
3562 #if ENABLE_HUSH_LOOPS
3563 [RES_FOR ] = "FOR" ,
3564 [RES_WHILE] = "WHILE",
3565 [RES_UNTIL] = "UNTIL",
3567 [RES_DONE ] = "DONE" ,
3569 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
3572 #if ENABLE_HUSH_CASE
3573 [RES_CASE ] = "CASE" ,
3574 [RES_MATCH] = "MATCH",
3575 [RES_CASEI] = "CASEI",
3576 [RES_ESAC ] = "ESAC" ,
3578 [RES_XXXX ] = "XXXX" ,
3579 [RES_SNTX ] = "SNTX" ,
3581 static const char *const GRPTYPE[] = {
3584 #if ENABLE_HUSH_FUNCTIONS
3593 fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
3594 pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
3596 while (prn < pi->num_cmds) {
3597 struct command *command = &pi->cmds[prn];
3598 char **argv = command->argv;
3600 fprintf(stderr, "%*s cmd %d assignment_cnt:%d",
3602 command->assignment_cnt);
3603 if (command->group) {
3604 fprintf(stderr, " group %s: (argv=%p)\n",
3605 GRPTYPE[command->grp_type],
3607 debug_print_tree(command->group, lvl+1);
3611 if (argv) while (*argv) {
3612 fprintf(stderr, " '%s'", *argv);
3615 fprintf(stderr, "\n");
3624 /* NB: called by pseudo_exec, and therefore must not modify any
3625 * global data until exec/_exit (we can be a child after vfork!) */
3626 static int run_list(struct pipe *pi)
3628 #if ENABLE_HUSH_CASE
3629 char *case_word = NULL;
3631 #if ENABLE_HUSH_LOOPS
3632 struct pipe *loop_top = NULL;
3633 char *for_varname = NULL;
3634 char **for_lcur = NULL;
3635 char **for_list = NULL;
3637 smallint last_followup;
3639 #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
3640 smalluint cond_code = 0;
3642 enum { cond_code = 0 };
3645 smallint rword; /* enum reserved_style */
3646 smallint last_rword; /* ditto */
3649 debug_printf_exec("run_list start lvl %d\n", G.run_list_level);
3652 #if ENABLE_HUSH_LOOPS
3653 /* Check syntax for "for" */
3654 for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
3655 if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
3657 /* current word is FOR or IN (BOLD in comments below) */
3658 if (cpipe->next == NULL) {
3659 syntax_error("malformed for");
3661 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3664 /* "FOR v; do ..." and "for v IN a b; do..." are ok */
3665 if (cpipe->next->res_word == RES_DO)
3667 /* next word is not "do". It must be "in" then ("FOR v in ...") */
3668 if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
3669 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
3671 syntax_error("malformed for");
3673 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3679 /* Past this point, all code paths should jump to ret: label
3680 * in order to return, no direct "return" statements please.
3681 * This helps to ensure that no memory is leaked. */
3689 last_rword = RES_XXXX;
3691 last_followup = PIPE_SEQ;
3692 rcode = G.last_exitcode;
3694 /* Go through list of pipes, (maybe) executing them. */
3695 for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
3699 IF_HAS_KEYWORDS(rword = pi->res_word;)
3700 debug_printf_exec(": rword=%d cond_code=%d last_rword=%d\n",
3701 rword, cond_code, last_rword);
3702 #if ENABLE_HUSH_LOOPS
3703 if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
3704 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
3706 /* start of a loop: remember where loop starts */
3711 /* Still in the same "if...", "then..." or "do..." branch? */
3712 if (IF_HAS_KEYWORDS(rword == last_rword &&) 1) {
3713 if ((rcode == 0 && last_followup == PIPE_OR)
3714 || (rcode != 0 && last_followup == PIPE_AND)
3716 /* It is "<true> || CMD" or "<false> && CMD"
3717 * and we should not execute CMD */
3718 debug_printf_exec("skipped cmd because of || or &&\n");
3719 last_followup = pi->followup;
3723 last_followup = pi->followup;
3724 IF_HAS_KEYWORDS(last_rword = rword;)
3727 if (rword == RES_THEN) {
3728 /* if false; then ... fi has exitcode 0! */
3729 G.last_exitcode = rcode = EXIT_SUCCESS;
3730 /* "if <false> THEN cmd": skip cmd */
3734 if (rword == RES_ELSE || rword == RES_ELIF) {
3735 /* "if <true> then ... ELSE/ELIF cmd":
3736 * skip cmd and all following ones */
3741 #if ENABLE_HUSH_LOOPS
3742 if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
3744 /* first loop through for */
3746 static const char encoded_dollar_at[] ALIGN1 = {
3747 SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
3748 }; /* encoded representation of "$@" */
3749 static const char *const encoded_dollar_at_argv[] = {
3750 encoded_dollar_at, NULL
3751 }; /* argv list with one element: "$@" */
3754 vals = (char**)encoded_dollar_at_argv;
3755 if (pi->next->res_word == RES_IN) {
3756 /* if no variable values after "in" we skip "for" */
3757 if (!pi->next->cmds[0].argv) {
3758 G.last_exitcode = rcode = EXIT_SUCCESS;
3759 debug_printf_exec(": null FOR: exitcode EXIT_SUCCESS\n");
3762 vals = pi->next->cmds[0].argv;
3763 } /* else: "for var; do..." -> assume "$@" list */
3764 /* create list of variable values */
3765 debug_print_strings("for_list made from", vals);
3766 for_list = expand_strvec_to_strvec(vals);
3767 for_lcur = for_list;
3768 debug_print_strings("for_list", for_list);
3769 for_varname = pi->cmds[0].argv[0];
3770 pi->cmds[0].argv[0] = NULL;
3772 free(pi->cmds[0].argv[0]);
3774 /* "for" loop is over, clean up */
3778 pi->cmds[0].argv[0] = for_varname;
3781 /* Insert next value from for_lcur */
3782 /* note: *for_lcur already has quotes removed, $var expanded, etc */
3783 pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
3784 pi->cmds[0].assignment_cnt = 1;
3786 if (rword == RES_IN) {
3787 continue; /* "for v IN list;..." - "in" has no cmds anyway */
3789 if (rword == RES_DONE) {
3790 continue; /* "done" has no cmds too */
3793 #if ENABLE_HUSH_CASE
3794 if (rword == RES_CASE) {
3795 case_word = expand_strvec_to_string(pi->cmds->argv);
3798 if (rword == RES_MATCH) {
3801 if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
3803 /* all prev words didn't match, does this one match? */
3804 argv = pi->cmds->argv;
3806 char *pattern = expand_string_to_string(*argv);
3807 /* TODO: which FNM_xxx flags to use? */
3808 cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
3810 if (cond_code == 0) { /* match! we will execute this branch */
3811 free(case_word); /* make future "word)" stop */
3819 if (rword == RES_CASEI) { /* inside of a case branch */
3821 continue; /* not matched yet, skip this pipe */
3824 /* Just pressing <enter> in shell should check for jobs.
3825 * OTOH, in non-interactive shell this is useless
3826 * and only leads to extra job checks */
3827 if (pi->num_cmds == 0) {
3828 if (G_interactive_fd)
3829 goto check_jobs_and_continue;
3833 /* After analyzing all keywords and conditions, we decided
3834 * to execute this pipe. NB: have to do checkjobs(NULL)
3835 * after run_pipe to collect any background children,
3836 * even if list execution is to be stopped. */
3837 debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
3840 #if ENABLE_HUSH_LOOPS
3841 G.flag_break_continue = 0;
3843 rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
3845 /* We only ran a builtin: rcode is already known
3846 * and we don't need to wait for anything. */
3847 G.last_exitcode = rcode;
3848 debug_printf_exec(": builtin/func exitcode %d\n", rcode);
3849 check_and_run_traps(0);
3850 #if ENABLE_HUSH_LOOPS
3851 /* Was it "break" or "continue"? */
3852 if (G.flag_break_continue) {
3853 smallint fbc = G.flag_break_continue;
3854 /* We might fall into outer *loop*,
3855 * don't want to break it too */
3857 G.depth_break_continue--;
3858 if (G.depth_break_continue == 0)
3859 G.flag_break_continue = 0;
3860 /* else: e.g. "continue 2" should *break* once, *then* continue */
3861 } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
3862 if (G.depth_break_continue != 0 || fbc == BC_BREAK)
3863 goto check_jobs_and_break;
3864 /* "continue": simulate end of loop */
3869 } else if (pi->followup == PIPE_BG) {
3870 /* What does bash do with attempts to background builtins? */
3871 /* even bash 3.2 doesn't do that well with nested bg:
3872 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
3873 * I'm NOT treating inner &'s as jobs */
3874 check_and_run_traps(0);
3876 if (G.run_list_level == 1)
3879 G.last_exitcode = rcode = EXIT_SUCCESS;
3880 debug_printf_exec(": cmd&: exitcode EXIT_SUCCESS\n");
3883 if (G.run_list_level == 1 && G_interactive_fd) {
3884 /* Waits for completion, then fg's main shell */
3885 rcode = checkjobs_and_fg_shell(pi);
3886 debug_printf_exec(": checkjobs_and_fg_shell exitcode %d\n", rcode);
3887 check_and_run_traps(0);
3890 { /* This one just waits for completion */
3891 rcode = checkjobs(pi);
3892 debug_printf_exec(": checkjobs exitcode %d\n", rcode);
3893 check_and_run_traps(0);
3895 G.last_exitcode = rcode;
3899 /* Analyze how result affects subsequent commands */
3901 if (rword == RES_IF || rword == RES_ELIF)
3904 #if ENABLE_HUSH_LOOPS
3905 /* Beware of "while false; true; do ..."! */
3906 if (pi->next && pi->next->res_word == RES_DO) {
3907 if (rword == RES_WHILE) {
3909 /* "while false; do...done" - exitcode 0 */
3910 G.last_exitcode = rcode = EXIT_SUCCESS;
3911 debug_printf_exec(": while expr is false: breaking (exitcode:EXIT_SUCCESS)\n");
3912 goto check_jobs_and_break;
3915 if (rword == RES_UNTIL) {
3917 debug_printf_exec(": until expr is true: breaking\n");
3918 check_jobs_and_break:
3926 check_jobs_and_continue:
3933 #if ENABLE_HUSH_LOOPS
3938 #if ENABLE_HUSH_CASE
3942 debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
3946 /* Select which version we will use */
3947 static int run_and_free_list(struct pipe *pi)
3950 debug_printf_exec("run_and_free_list entered\n");
3952 debug_printf_exec(": run_list: 1st pipe with %d cmds\n", pi->num_cmds);
3953 rcode = run_list(pi);
3955 /* free_pipe_list has the side effect of clearing memory.
3956 * In the long run that function can be merged with run_list,
3957 * but doing that now would hobble the debugging effort. */
3959 debug_printf_exec("run_and_free_list return %d\n", rcode);
3964 static struct pipe *new_pipe(void)
3967 pi = xzalloc(sizeof(struct pipe));
3968 /*pi->followup = 0; - deliberately invalid value */
3969 /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
3973 /* Command (member of a pipe) is complete. The only possible error here
3974 * is out of memory, in which case xmalloc exits. */
3975 static int done_command(struct parse_context *ctx)
3977 /* The command is really already in the pipe structure, so
3978 * advance the pipe counter and make a new, null command. */
3979 struct pipe *pi = ctx->pipe;
3980 struct command *command = ctx->command;
3983 if (command->group == NULL
3984 && command->argv == NULL
3985 && command->redirects == NULL
3987 debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
3988 memset(command, 0, sizeof(*command)); /* paranoia */
3989 return pi->num_cmds;
3992 debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
3993 //debug_print_tree(ctx->list_head, 20);
3995 debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
3998 /* Only real trickiness here is that the uncommitted
3999 * command structure is not counted in pi->num_cmds. */
4000 pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
4001 command = &pi->cmds[pi->num_cmds];
4002 memset(command, 0, sizeof(*command));
4004 ctx->command = command;
4005 /* but ctx->pipe and ctx->list_head remain unchanged */
4007 return pi->num_cmds; /* used only for 0/nonzero check */
4010 static void done_pipe(struct parse_context *ctx, pipe_style type)
4014 debug_printf_parse("done_pipe entered, followup %d\n", type);
4015 /* Close previous command */
4016 not_null = done_command(ctx);
4017 ctx->pipe->followup = type;
4019 ctx->pipe->pi_inverted = ctx->ctx_inverted;
4020 ctx->ctx_inverted = 0;
4021 ctx->pipe->res_word = ctx->ctx_res_w;
4024 /* Without this check, even just <enter> on command line generates
4025 * tree of three NOPs (!). Which is harmless but annoying.
4026 * IOW: it is safe to do it unconditionally.
4027 * RES_NONE case is for "for a in; do ..." (empty IN set)
4028 * and other cases to work. */
4031 || ctx->ctx_res_w == RES_FI
4033 #if ENABLE_HUSH_LOOPS
4034 || ctx->ctx_res_w == RES_DONE
4035 || ctx->ctx_res_w == RES_FOR
4036 || ctx->ctx_res_w == RES_IN
4038 #if ENABLE_HUSH_CASE
4039 || ctx->ctx_res_w == RES_ESAC
4043 debug_printf_parse("done_pipe: adding new pipe: "
4044 "not_null:%d ctx->ctx_res_w:%d\n",
4045 not_null, ctx->ctx_res_w);
4047 ctx->pipe->next = new_p;
4049 /* RES_THEN, RES_DO etc are "sticky" -
4050 * they remain set for commands inside if/while.
4051 * This is used to control execution.
4052 * RES_FOR and RES_IN are NOT sticky (needed to support
4053 * cases where variable or value happens to match a keyword):
4055 #if ENABLE_HUSH_LOOPS
4056 if (ctx->ctx_res_w == RES_FOR
4057 || ctx->ctx_res_w == RES_IN)
4058 ctx->ctx_res_w = RES_NONE;
4060 #if ENABLE_HUSH_CASE
4061 if (ctx->ctx_res_w == RES_MATCH)
4062 ctx->ctx_res_w = RES_CASEI;
4064 ctx->command = NULL; /* trick done_command below */
4065 /* Create the memory for command, roughly:
4066 * ctx->pipe->cmds = new struct command;
4067 * ctx->command = &ctx->pipe->cmds[0];
4070 //debug_print_tree(ctx->list_head, 10);
4072 debug_printf_parse("done_pipe return\n");
4075 static void initialize_context(struct parse_context *ctx)
4077 memset(ctx, 0, sizeof(*ctx));
4078 ctx->pipe = ctx->list_head = new_pipe();
4079 /* Create the memory for command, roughly:
4080 * ctx->pipe->cmds = new struct command;
4081 * ctx->command = &ctx->pipe->cmds[0];
4086 /* If a reserved word is found and processed, parse context is modified
4087 * and 1 is returned.
4090 struct reserved_combo {
4093 unsigned char assignment_flag;
4097 FLAG_END = (1 << RES_NONE ),
4099 FLAG_IF = (1 << RES_IF ),
4100 FLAG_THEN = (1 << RES_THEN ),
4101 FLAG_ELIF = (1 << RES_ELIF ),
4102 FLAG_ELSE = (1 << RES_ELSE ),
4103 FLAG_FI = (1 << RES_FI ),
4105 #if ENABLE_HUSH_LOOPS
4106 FLAG_FOR = (1 << RES_FOR ),
4107 FLAG_WHILE = (1 << RES_WHILE),
4108 FLAG_UNTIL = (1 << RES_UNTIL),
4109 FLAG_DO = (1 << RES_DO ),
4110 FLAG_DONE = (1 << RES_DONE ),
4111 FLAG_IN = (1 << RES_IN ),
4113 #if ENABLE_HUSH_CASE
4114 FLAG_MATCH = (1 << RES_MATCH),
4115 FLAG_ESAC = (1 << RES_ESAC ),
4117 FLAG_START = (1 << RES_XXXX ),
4120 static const struct reserved_combo* match_reserved_word(o_string *word)
4122 /* Mostly a list of accepted follow-up reserved words.
4123 * FLAG_END means we are done with the sequence, and are ready
4124 * to turn the compound list into a command.
4125 * FLAG_START means the word must start a new compound list.
4127 static const struct reserved_combo reserved_list[] = {
4129 { "!", RES_NONE, NOT_ASSIGNMENT , 0 },
4130 { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START },
4131 { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
4132 { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN },
4133 { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI },
4134 { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
4136 #if ENABLE_HUSH_LOOPS
4137 { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
4138 { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
4139 { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
4140 { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
4141 { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE },
4142 { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
4144 #if ENABLE_HUSH_CASE
4145 { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
4146 { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
4149 const struct reserved_combo *r;
4151 for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
4152 if (strcmp(word->data, r->literal) == 0)
4157 /* Return 0: not a keyword, 1: keyword
4159 static int reserved_word(o_string *word, struct parse_context *ctx)
4161 #if ENABLE_HUSH_CASE
4162 static const struct reserved_combo reserved_match = {
4163 "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
4166 const struct reserved_combo *r;
4170 r = match_reserved_word(word);
4174 debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
4175 #if ENABLE_HUSH_CASE
4176 if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE)
4177 /* "case word IN ..." - IN part starts first match part */
4178 r = &reserved_match;
4181 if (r->flag == 0) { /* '!' */
4182 if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
4183 syntax_error("! ! command");
4184 ctx->ctx_res_w = RES_SNTX;
4186 ctx->ctx_inverted = 1;
4189 if (r->flag & FLAG_START) {
4190 struct parse_context *old;
4192 old = xmalloc(sizeof(*old));
4193 debug_printf_parse("push stack %p\n", old);
4194 *old = *ctx; /* physical copy */
4195 initialize_context(ctx);
4197 } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
4198 syntax_error_at(word->data);
4199 ctx->ctx_res_w = RES_SNTX;
4202 /* "{...} fi" is ok. "{...} if" is not
4204 * if { echo foo; } then { echo bar; } fi */
4205 if (ctx->command->group)
4206 done_pipe(ctx, PIPE_SEQ);
4209 ctx->ctx_res_w = r->res;
4210 ctx->old_flag = r->flag;
4211 word->o_assignment = r->assignment_flag;
4213 if (ctx->old_flag & FLAG_END) {
4214 struct parse_context *old;
4216 done_pipe(ctx, PIPE_SEQ);
4217 debug_printf_parse("pop stack %p\n", ctx->stack);
4219 old->command->group = ctx->list_head;
4220 old->command->grp_type = GRP_NORMAL;
4222 o_addstr(&old->as_string, ctx->as_string.data);
4223 o_free_unsafe(&ctx->as_string);
4224 old->command->group_as_string = xstrdup(old->as_string.data);
4225 debug_printf_parse("pop, remembering as:'%s'\n",
4226 old->command->group_as_string);
4228 *ctx = *old; /* physical copy */
4235 /* Word is complete, look at it and update parsing context.
4236 * Normal return is 0. Syntax errors return 1.
4237 * Note: on return, word is reset, but not o_free'd!
4239 static int done_word(o_string *word, struct parse_context *ctx)
4241 struct command *command = ctx->command;
4243 debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
4244 if (word->length == 0 && word->o_quoted == 0) {
4245 debug_printf_parse("done_word return 0: true null, ignored\n");
4249 if (ctx->pending_redirect) {
4250 /* We do not glob in e.g. >*.tmp case. bash seems to glob here
4251 * only if run as "bash", not "sh" */
4252 /* http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
4254 * ...the word that follows the redirection operator
4255 * shall be subjected to tilde expansion, parameter expansion,
4256 * command substitution, arithmetic expansion, and quote
4257 * removal. Pathname expansion shall not be performed
4258 * on the word by a non-interactive shell; an interactive
4259 * shell may perform it, but shall do so only when
4260 * the expansion would result in one word."
4262 ctx->pending_redirect->rd_filename = xstrdup(word->data);
4263 /* Cater for >\file case:
4264 * >\a creates file a; >\\a, >"\a", >"\\a" create file \a
4265 * Same with heredocs:
4266 * for <<\H delim is H; <<\\H, <<"\H", <<"\\H" - \H
4268 unbackslash(ctx->pending_redirect->rd_filename);
4269 /* Is it <<"HEREDOC"? */
4270 if (ctx->pending_redirect->rd_type == REDIRECT_HEREDOC
4273 ctx->pending_redirect->rd_dup |= HEREDOC_QUOTED;
4275 debug_printf_parse("word stored in rd_filename: '%s'\n", word->data);
4276 ctx->pending_redirect = NULL;
4278 /* If this word wasn't an assignment, next ones definitely
4279 * can't be assignments. Even if they look like ones. */
4280 if (word->o_assignment != DEFINITELY_ASSIGNMENT
4281 && word->o_assignment != WORD_IS_KEYWORD
4283 word->o_assignment = NOT_ASSIGNMENT;
4285 if (word->o_assignment == DEFINITELY_ASSIGNMENT)
4286 command->assignment_cnt++;
4287 word->o_assignment = MAYBE_ASSIGNMENT;
4291 # if ENABLE_HUSH_CASE
4292 if (ctx->ctx_dsemicolon
4293 && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
4295 /* already done when ctx_dsemicolon was set to 1: */
4296 /* ctx->ctx_res_w = RES_MATCH; */
4297 ctx->ctx_dsemicolon = 0;
4300 if (!command->argv /* if it's the first word... */
4301 # if ENABLE_HUSH_LOOPS
4302 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
4303 && ctx->ctx_res_w != RES_IN
4306 debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
4307 if (reserved_word(word, ctx)) {
4308 o_reset_to_empty_unquoted(word);
4309 debug_printf_parse("done_word return %d\n",
4310 (ctx->ctx_res_w == RES_SNTX));
4311 return (ctx->ctx_res_w == RES_SNTX);
4315 if (command->group) {
4316 /* "{ echo foo; } echo bar" - bad */
4317 syntax_error_at(word->data);
4318 debug_printf_parse("done_word return 1: syntax error, "
4319 "groups and arglists don't mix\n");
4322 if (word->o_quoted /* word had "xx" or 'xx' at least as part of it. */
4323 /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
4324 && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
4325 /* (otherwise it's known to be not empty and is already safe) */
4327 /* exclude "$@" - it can expand to no word despite "" */
4328 char *p = word->data;
4329 while (p[0] == SPECIAL_VAR_SYMBOL
4330 && (p[1] & 0x7f) == '@'
4331 && p[2] == SPECIAL_VAR_SYMBOL
4335 if (p == word->data || p[0] != '\0') {
4336 /* saw no "$@", or not only "$@" but some
4337 * real text is there too */
4338 /* insert "empty variable" reference, this makes
4339 * e.g. "", $empty"" etc to not disappear */
4340 o_addchr(word, SPECIAL_VAR_SYMBOL);
4341 o_addchr(word, SPECIAL_VAR_SYMBOL);
4344 command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
4345 //SEGV, but good idea.
4346 // command->argv = add_string_to_strings(command->argv, word->data);
4347 // word->data = NULL;
4348 // word->length = 0;
4349 debug_print_strings("word appended to argv", command->argv);
4352 #if ENABLE_HUSH_LOOPS
4353 if (ctx->ctx_res_w == RES_FOR) {
4355 || !is_well_formed_var_name(command->argv[0], '\0')
4357 /* bash says just "not a valid identifier" */
4358 syntax_error("not a valid identifier in for");
4361 /* Force FOR to have just one word (variable name) */
4362 /* NB: basically, this makes hush see "for v in ..."
4363 * syntax as if it is "for v; in ...". FOR and IN become
4364 * two pipe structs in parse tree. */
4365 done_pipe(ctx, PIPE_SEQ);
4368 #if ENABLE_HUSH_CASE
4369 /* Force CASE to have just one word */
4370 if (ctx->ctx_res_w == RES_CASE) {
4371 done_pipe(ctx, PIPE_SEQ);
4375 o_reset_to_empty_unquoted(word);
4377 debug_printf_parse("done_word return 0\n");
4382 /* Peek ahead in the input to find out if we have a "&n" construct,
4383 * as in "2>&1", that represents duplicating a file descriptor.
4385 * REDIRFD_CLOSE if >&- "close fd" construct is seen,
4386 * REDIRFD_SYNTAX_ERR if syntax error,
4387 * REDIRFD_TO_FILE if no & was seen,
4388 * or the number found.
4391 #define parse_redir_right_fd(as_string, input) \
4392 parse_redir_right_fd(input)
4394 static int parse_redir_right_fd(o_string *as_string, struct in_str *input)
4400 return REDIRFD_TO_FILE;
4402 ch = i_getch(input); /* get the & */
4403 nommu_addchr(as_string, ch);
4406 ch = i_getch(input);
4407 nommu_addchr(as_string, ch);
4408 return REDIRFD_CLOSE;
4412 while (ch != EOF && isdigit(ch)) {
4413 d = d*10 + (ch-'0');
4415 ch = i_getch(input);
4416 nommu_addchr(as_string, ch);
4421 //TODO: this is the place to catch ">&file" bashism (redirect both fd 1 and 2)
4423 bb_error_msg("ambiguous redirect");
4424 return REDIRFD_SYNTAX_ERR;
4427 /* Return code is 0 normal, 1 if a syntax error is detected
4429 static int parse_redirect(struct parse_context *ctx,
4432 struct in_str *input)
4434 struct command *command = ctx->command;
4435 struct redir_struct *redir;
4436 struct redir_struct **redirp;
4439 dup_num = REDIRFD_TO_FILE;
4440 if (style != REDIRECT_HEREDOC) {
4441 /* Check for a '>&1' type redirect */
4442 dup_num = parse_redir_right_fd(&ctx->as_string, input);
4443 if (dup_num == REDIRFD_SYNTAX_ERR)
4446 int ch = i_peek(input);
4447 dup_num = (ch == '-'); /* HEREDOC_SKIPTABS bit is 1 */
4448 if (dup_num) { /* <<-... */
4449 ch = i_getch(input);
4450 nommu_addchr(&ctx->as_string, ch);
4455 if (style == REDIRECT_OVERWRITE && dup_num == REDIRFD_TO_FILE) {
4456 int ch = i_peek(input);
4458 /* >|FILE redirect ("clobbering" >).
4459 * Since we do not support "set -o noclobber" yet,
4460 * >| and > are the same for now. Just eat |.
4462 ch = i_getch(input);
4463 nommu_addchr(&ctx->as_string, ch);
4467 /* Create a new redir_struct and append it to the linked list */
4468 redirp = &command->redirects;
4469 while ((redir = *redirp) != NULL) {
4470 redirp = &(redir->next);
4472 *redirp = redir = xzalloc(sizeof(*redir));
4473 /* redir->next = NULL; */
4474 /* redir->rd_filename = NULL; */
4475 redir->rd_type = style;
4476 redir->rd_fd = (fd == -1) ? redir_table[style].default_fd : fd;
4478 debug_printf_parse("redirect type %d %s\n", redir->rd_fd,
4479 redir_table[style].descrip);
4481 redir->rd_dup = dup_num;
4482 if (style != REDIRECT_HEREDOC && dup_num != REDIRFD_TO_FILE) {
4483 /* Erik had a check here that the file descriptor in question
4484 * is legit; I postpone that to "run time"
4485 * A "-" representation of "close me" shows up as a -3 here */
4486 debug_printf_parse("duplicating redirect '%d>&%d'\n",
4487 redir->rd_fd, redir->rd_dup);
4489 /* Set ctx->pending_redirect, so we know what to do at the
4490 * end of the next parsed word. */
4491 ctx->pending_redirect = redir;
4496 /* If a redirect is immediately preceded by a number, that number is
4497 * supposed to tell which file descriptor to redirect. This routine
4498 * looks for such preceding numbers. In an ideal world this routine
4499 * needs to handle all the following classes of redirects...
4500 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
4501 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
4502 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
4503 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
4505 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
4507 * ... If n is quoted, the number shall not be recognized as part of
4508 * the redirection expression. For example:
4510 * writes the character 2 into file a"
4511 * We are getting it right by setting ->o_quoted on any \<char>
4513 * A -1 return means no valid number was found,
4514 * the caller should use the appropriate default for this redirection.
4516 static int redirect_opt_num(o_string *o)
4520 if (o->data == NULL)
4522 num = bb_strtou(o->data, NULL, 10);
4523 if (errno || num < 0)
4525 o_reset_to_empty_unquoted(o);
4530 #define fetch_till_str(as_string, input, word, skip_tabs) \
4531 fetch_till_str(input, word, skip_tabs)
4533 static char *fetch_till_str(o_string *as_string,
4534 struct in_str *input,
4538 o_string heredoc = NULL_O_STRING;
4544 ch = i_getch(input);
4545 nommu_addchr(as_string, ch);
4547 if (strcmp(heredoc.data + past_EOL, word) == 0) {
4548 heredoc.data[past_EOL] = '\0';
4549 debug_printf_parse("parsed heredoc '%s'\n", heredoc.data);
4550 return heredoc.data;
4553 o_addchr(&heredoc, ch);
4554 past_EOL = heredoc.length;
4557 ch = i_getch(input);
4558 nommu_addchr(as_string, ch);
4559 } while (skip_tabs && ch == '\t');
4560 } while (ch == '\n');
4563 o_free_unsafe(&heredoc);
4566 o_addchr(&heredoc, ch);
4567 nommu_addchr(as_string, ch);
4571 /* Look at entire parse tree for not-yet-loaded REDIRECT_HEREDOCs
4572 * and load them all. There should be exactly heredoc_cnt of them.
4574 static int fetch_heredocs(int heredoc_cnt, struct parse_context *ctx, struct in_str *input)
4576 struct pipe *pi = ctx->list_head;
4578 while (pi && heredoc_cnt) {
4580 struct command *cmd = pi->cmds;
4582 debug_printf_parse("fetch_heredocs: num_cmds:%d cmd argv0:'%s'\n",
4584 cmd->argv ? cmd->argv[0] : "NONE");
4585 for (i = 0; i < pi->num_cmds; i++) {
4586 struct redir_struct *redir = cmd->redirects;
4588 debug_printf_parse("fetch_heredocs: %d cmd argv0:'%s'\n",
4589 i, cmd->argv ? cmd->argv[0] : "NONE");
4591 if (redir->rd_type == REDIRECT_HEREDOC) {
4594 redir->rd_type = REDIRECT_HEREDOC2;
4595 /* redir->dup is (ab)used to indicate <<- */
4596 p = fetch_till_str(&ctx->as_string, input,
4597 redir->rd_filename, redir->rd_dup & HEREDOC_SKIPTABS);
4599 syntax_error("unexpected EOF in here document");
4602 free(redir->rd_filename);
4603 redir->rd_filename = p;
4606 redir = redir->next;
4613 /* Should be 0. If it isn't, it's a parse error */
4615 bb_error_msg_and_die("heredoc BUG 2");
4621 #if ENABLE_HUSH_TICK
4622 static FILE *generate_stream_from_string(const char *s)
4625 int pid, channel[2];
4631 pid = BB_MMU ? fork() : vfork();
4633 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
4635 if (pid == 0) { /* child */
4636 disable_restore_tty_pgrp_on_exit();
4637 /* Process substitution is not considered to be usual
4638 * 'command execution'.
4639 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
4646 close(channel[0]); /* NB: close _first_, then move fd! */
4647 xmove_fd(channel[1], 1);
4648 /* Prevent it from trying to handle ctrl-z etc */
4649 USE_HUSH_JOB(G.run_list_level = 1;)
4651 reset_traps_to_defaults();
4652 parse_and_run_string(s);
4653 _exit(G.last_exitcode);
4655 /* We re-execute after vfork on NOMMU. This makes this script safe:
4656 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >BIG
4657 * huge=`cat BIG` # was blocking here forever
4660 re_execute_shell(&to_free,
4668 enable_restore_tty_pgrp_on_exit();
4673 pf = fdopen(channel[0], "r");
4677 /* Return code is exit status of the process that is run. */
4678 static int process_command_subs(o_string *dest, const char *s)
4681 struct in_str pipe_str;
4684 pf = generate_stream_from_string(s);
4687 close_on_exec_on(fileno(pf));
4689 /* Now send results of command back into original context */
4690 setup_file_in_str(&pipe_str, pf);
4692 while ((ch = i_getch(&pipe_str)) != EOF) {
4698 o_addchr(dest, '\n');
4701 o_addQchr(dest, ch);
4704 debug_printf("done reading from pipe, pclose()ing\n");
4705 /* Note: we got EOF, and we just close the read end of the pipe.
4706 * We do not wait for the `cmd` child to terminate. bash and ash do.
4708 * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec
4709 * `false`; echo $? - bash outputs "1"
4712 debug_printf("closed FILE from child. return 0\n");
4717 static int parse_group(o_string *dest, struct parse_context *ctx,
4718 struct in_str *input, int ch)
4720 /* dest contains characters seen prior to ( or {.
4721 * Typically it's empty, but for function defs,
4722 * it contains function name (without '()'). */
4723 struct pipe *pipe_list;
4725 struct command *command = ctx->command;
4727 debug_printf_parse("parse_group entered\n");
4728 #if ENABLE_HUSH_FUNCTIONS
4729 if (ch == '(' && !dest->o_quoted) {
4731 if (done_word(dest, ctx))
4734 goto skip; /* (... */
4735 if (command->argv[1]) { /* word word ... (... */
4736 syntax_error_unexpected_ch('(');
4739 /* it is "word(..." or "word (..." */
4741 ch = i_getch(input);
4742 while (ch == ' ' || ch == '\t');
4744 syntax_error_unexpected_ch(ch);
4747 nommu_addchr(&ctx->as_string, ch);
4749 ch = i_getch(input);
4750 while (ch == ' ' || ch == '\t' || ch == '\n');
4752 syntax_error_unexpected_ch(ch);
4755 nommu_addchr(&ctx->as_string, ch);
4756 command->grp_type = GRP_FUNCTION;
4760 if (command->argv /* word [word]{... */
4761 || dest->length /* word{... */
4762 || dest->o_quoted /* ""{... */
4765 debug_printf_parse("parse_group return 1: "
4766 "syntax error, groups and arglists don't mix\n");
4770 #if ENABLE_HUSH_FUNCTIONS
4776 command->grp_type = GRP_SUBSHELL;
4781 char *as_string = NULL;
4783 pipe_list = parse_stream(&as_string, input, endch);
4786 o_addstr(&ctx->as_string, as_string);
4788 /* empty ()/{} or parse error? */
4789 if (!pipe_list || pipe_list == ERR_PTR) {
4790 /* parse_stream already emitted error msg */
4794 debug_printf_parse("parse_group return 1: "
4795 "parse_stream returned %p\n", pipe_list);
4798 command->group = pipe_list;
4800 as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
4801 command->group_as_string = as_string;
4802 debug_printf_parse("end of group, remembering as:'%s'\n",
4803 command->group_as_string);
4806 debug_printf_parse("parse_group return 0\n");
4808 /* command remains "open", available for possible redirects */
4811 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
4812 /* Subroutines for copying $(...) and `...` things */
4813 static void add_till_backquote(o_string *dest, struct in_str *input);
4815 static void add_till_single_quote(o_string *dest, struct in_str *input)
4818 int ch = i_getch(input);
4820 syntax_error_unterm_ch('\'');
4821 /*xfunc_die(); - redundant */
4828 /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
4829 static void add_till_double_quote(o_string *dest, struct in_str *input)
4832 int ch = i_getch(input);
4834 syntax_error_unterm_ch('"');
4835 /*xfunc_die(); - redundant */
4839 if (ch == '\\') { /* \x. Copy both chars. */
4841 ch = i_getch(input);
4845 add_till_backquote(dest, input);
4849 //if (ch == '$') ...
4852 /* Process `cmd` - copy contents until "`" is seen. Complicated by
4854 * "Within the backquoted style of command substitution, backslash
4855 * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
4856 * The search for the matching backquote shall be satisfied by the first
4857 * backquote found without a preceding backslash; during this search,
4858 * if a non-escaped backquote is encountered within a shell comment,
4859 * a here-document, an embedded command substitution of the $(command)
4860 * form, or a quoted string, undefined results occur. A single-quoted
4861 * or double-quoted string that begins, but does not end, within the
4862 * "`...`" sequence produces undefined results."
4864 * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
4866 static void add_till_backquote(o_string *dest, struct in_str *input)
4869 int ch = i_getch(input);
4871 syntax_error_unterm_ch('`');
4872 /*xfunc_die(); - redundant */
4877 /* \x. Copy both chars unless it is \` */
4878 int ch2 = i_getch(input);
4880 syntax_error_unterm_ch('`');
4881 /*xfunc_die(); - redundant */
4883 if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
4890 /* Process $(cmd) - copy contents until ")" is seen. Complicated by
4891 * quoting and nested ()s.
4892 * "With the $(command) style of command substitution, all characters
4893 * following the open parenthesis to the matching closing parenthesis
4894 * constitute the command. Any valid shell script can be used for command,
4895 * except a script consisting solely of redirections which produces
4896 * unspecified results."
4898 * echo $(echo '(TEST)' BEST) (TEST) BEST
4899 * echo $(echo 'TEST)' BEST) TEST) BEST
4900 * echo $(echo \(\(TEST\) BEST) ((TEST) BEST
4902 static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
4906 int ch = i_getch(input);
4908 syntax_error_unterm_ch(')');
4909 /*xfunc_die(); - redundant */
4917 if (i_peek(input) == ')') {
4925 add_till_single_quote(dest, input);
4930 add_till_double_quote(dest, input);
4935 /* \x. Copy verbatim. Important for \(, \) */
4936 ch = i_getch(input);
4938 syntax_error_unterm_ch(')');
4939 /*xfunc_die(); - redundant */
4946 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
4948 /* Return code: 0 for OK, 1 for syntax error */
4950 #define handle_dollar(as_string, dest, input) \
4951 handle_dollar(dest, input)
4953 static int handle_dollar(o_string *as_string,
4955 struct in_str *input)
4958 int ch = i_peek(input); /* first character after the $ */
4959 unsigned char quote_mask = dest->o_escape ? 0x80 : 0;
4961 debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
4963 ch = i_getch(input);
4964 nommu_addchr(as_string, ch);
4966 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4968 debug_printf_parse(": '%c'\n", ch);
4969 o_addchr(dest, ch | quote_mask);
4972 if (!isalnum(ch) && ch != '_')
4974 ch = i_getch(input);
4975 nommu_addchr(as_string, ch);
4977 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4978 } else if (isdigit(ch)) {
4980 ch = i_getch(input);
4981 nommu_addchr(as_string, ch);
4982 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4983 debug_printf_parse(": '%c'\n", ch);
4984 o_addchr(dest, ch | quote_mask);
4985 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4986 } else switch (ch) {
4988 case '!': /* last bg pid */
4989 case '?': /* last exit code */
4990 case '#': /* number of args */
4991 case '*': /* args */
4992 case '@': /* args */
4993 goto make_one_char_var;
4995 bool first_char, all_digits;
4997 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4998 ch = i_getch(input);
4999 nommu_addchr(as_string, ch);
5000 /* XXX maybe someone will try to escape the '}' */
5005 ch = i_getch(input);
5006 nommu_addchr(as_string, ch);
5012 /* ${#var}: length of var contents */
5014 else if (isdigit(ch)) {
5021 && ( (all_digits && !isdigit(ch))
5022 || (!all_digits && !isalnum(ch) && ch != '_')
5025 /* handle parameter expansions
5026 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
5031 case ':': /* null modifier */
5032 if (expansion == 0) {
5033 debug_printf_parse(": null modifier\n");
5038 case '#': /* remove prefix */
5039 case '%': /* remove suffix */
5040 if (expansion == 0) {
5041 debug_printf_parse(": remove suffix/prefix\n");
5046 case '-': /* default value */
5047 case '=': /* assign default */
5048 case '+': /* alternative */
5049 case '?': /* error indicate */
5050 debug_printf_parse(": parameter expansion\n");
5055 syntax_error_unterm_str("${name}");
5056 debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
5061 debug_printf_parse(": '%c'\n", ch);
5062 o_addchr(dest, ch | quote_mask);
5066 o_addchr(dest, SPECIAL_VAR_SYMBOL);
5069 #if (ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_TICK)
5074 ch = i_getch(input);
5075 nommu_addchr(as_string, ch);
5076 # if ENABLE_SH_MATH_SUPPORT
5077 if (i_peek(input) == '(') {
5078 ch = i_getch(input);
5079 nommu_addchr(as_string, ch);
5080 o_addchr(dest, SPECIAL_VAR_SYMBOL);
5081 o_addchr(dest, /*quote_mask |*/ '+');
5085 add_till_closing_paren(dest, input, true);
5088 o_addstr(as_string, dest->data + pos);
5089 o_addchr(as_string, ')');
5090 o_addchr(as_string, ')');
5093 o_addchr(dest, SPECIAL_VAR_SYMBOL);
5097 # if ENABLE_HUSH_TICK
5098 o_addchr(dest, SPECIAL_VAR_SYMBOL);
5099 o_addchr(dest, quote_mask | '`');
5103 add_till_closing_paren(dest, input, false);
5106 o_addstr(as_string, dest->data + pos);
5107 o_addchr(as_string, '`');
5110 o_addchr(dest, SPECIAL_VAR_SYMBOL);
5116 ch = i_getch(input);
5117 nommu_addchr(as_string, ch);
5119 if (isalnum(ch)) { /* it's $_name or $_123 */
5125 /* $_ Shell or shell script name; or last cmd name */
5126 /* $- Option flags set by set builtin or shell options (-i etc) */
5128 o_addQchr(dest, '$');
5130 debug_printf_parse("handle_dollar return 0\n");
5135 #define parse_stream_dquoted(as_string, dest, input, dquote_end) \
5136 parse_stream_dquoted(dest, input, dquote_end)
5138 static int parse_stream_dquoted(o_string *as_string,
5140 struct in_str *input,
5147 ch = i_getch(input);
5149 nommu_addchr(as_string, ch);
5150 if (ch == dquote_end) { /* may be only '"' or EOF */
5151 if (dest->o_assignment == NOT_ASSIGNMENT)
5152 dest->o_escape ^= 1;
5153 debug_printf_parse("parse_stream_dquoted return 0\n");
5156 /* note: can't move it above ch == dquote_end check! */
5158 syntax_error_unterm_ch('"');
5159 /*xfunc_die(); - redundant */
5163 next = i_peek(input);
5165 debug_printf_parse(": ch=%c (%d) escape=%d\n",
5166 ch, ch, dest->o_escape);
5169 syntax_error("\\<eof>");
5173 * "The backslash retains its special meaning [in "..."]
5174 * only when followed by one of the following characters:
5175 * $, `, ", \, or <newline>. A double quote may be quoted
5176 * within double quotes by preceding it with a backslash.
5178 if (strchr("$`\"\\", next) != NULL) {
5179 o_addqchr(dest, i_getch(input));
5181 o_addqchr(dest, '\\');
5186 if (handle_dollar(as_string, dest, input) != 0) {
5187 debug_printf_parse("parse_stream_dquoted return 1: "
5188 "handle_dollar returned non-0\n");
5193 #if ENABLE_HUSH_TICK
5195 //int pos = dest->length;
5196 o_addchr(dest, SPECIAL_VAR_SYMBOL);
5197 o_addchr(dest, 0x80 | '`');
5198 add_till_backquote(dest, input);
5199 o_addchr(dest, SPECIAL_VAR_SYMBOL);
5200 //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
5204 o_addQchr(dest, ch);
5206 && (dest->o_assignment == MAYBE_ASSIGNMENT
5207 || dest->o_assignment == WORD_IS_KEYWORD)
5208 && is_well_formed_var_name(dest->data, '=')
5210 dest->o_assignment = DEFINITELY_ASSIGNMENT;
5216 * Scan input until EOF or end_trigger char.
5217 * Return a list of pipes to execute, or NULL on EOF
5218 * or if end_trigger character is met.
5219 * On syntax error, exit is shell is not interactive,
5220 * reset parsing machinery and start parsing anew,
5221 * or return ERR_PTR.
5223 static struct pipe *parse_stream(char **pstring,
5224 struct in_str *input,
5227 struct parse_context ctx;
5228 o_string dest = NULL_O_STRING;
5232 /* Double-quote state is handled in the state variable is_in_dquote.
5233 * A single-quote triggers a bypass of the main loop until its mate is
5234 * found. When recursing, quote state is passed in via dest->o_escape.
5236 debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
5237 end_trigger ? : 'X');
5240 G.ifs = get_local_var_value("IFS");
5245 #if ENABLE_HUSH_INTERACTIVE
5246 input->promptmode = 0; /* PS1 */
5248 /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */
5249 initialize_context(&ctx);
5254 const char *is_special;
5258 redir_type redir_style;
5261 /* dest.o_quoted = 1; - already is (see below) */
5262 if (parse_stream_dquoted(&ctx.as_string, &dest, input, '"')) {
5265 /* We reached closing '"' */
5268 ch = i_getch(input);
5269 debug_printf_parse(": ch=%c (%d) escape=%d\n",
5270 ch, ch, dest.o_escape);
5275 syntax_error_unterm_str("here document");
5278 if (done_word(&dest, &ctx)) {
5282 done_pipe(&ctx, PIPE_SEQ);
5284 /* If we got nothing... */
5285 /* (this makes bare "&" cmd a no-op.
5286 * bash says: "syntax error near unexpected token '&'") */
5287 if (pi->num_cmds == 0
5288 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
5294 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
5296 *pstring = ctx.as_string.data;
5298 o_free_unsafe(&ctx.as_string);
5301 debug_printf_parse("parse_stream return %p\n", pi);
5304 nommu_addchr(&ctx.as_string, ch);
5305 is_ifs = strchr(G.ifs, ch);
5306 is_special = strchr("<>;&|(){}#'" /* special outside of "str" */
5307 "\\$\"" USE_HUSH_TICK("`") /* always special */
5310 if (!is_special && !is_ifs) { /* ordinary char */
5311 o_addQchr(&dest, ch);
5312 if ((dest.o_assignment == MAYBE_ASSIGNMENT
5313 || dest.o_assignment == WORD_IS_KEYWORD)
5315 && is_well_formed_var_name(dest.data, '=')
5317 dest.o_assignment = DEFINITELY_ASSIGNMENT;
5323 if (done_word(&dest, &ctx)) {
5327 #if ENABLE_HUSH_CASE
5328 /* "case ... in <newline> word) ..." -
5329 * newlines are ignored (but ';' wouldn't be) */
5330 if (ctx.command->argv == NULL
5331 && ctx.ctx_res_w == RES_MATCH
5336 /* Treat newline as a command separator. */
5337 done_pipe(&ctx, PIPE_SEQ);
5338 debug_printf_parse("heredoc_cnt:%d\n", heredoc_cnt);
5340 if (fetch_heredocs(heredoc_cnt, &ctx, input)) {
5345 dest.o_assignment = MAYBE_ASSIGNMENT;
5347 /* note: if (is_ifs) continue;
5348 * will still trigger for us */
5351 if (end_trigger && end_trigger == ch
5352 && (heredoc_cnt == 0 || end_trigger != ';')
5354 //TODO: disallow "{ cmd }" without semicolon
5356 /* This is technically valid:
5357 * { cat <<HERE; }; echo Ok
5362 * but we don't support this.
5363 * We require heredoc to be in enclosing {}/(),
5366 syntax_error_unterm_str("here document");
5369 if (done_word(&dest, &ctx)) {
5372 done_pipe(&ctx, PIPE_SEQ);
5373 dest.o_assignment = MAYBE_ASSIGNMENT;
5374 /* Do we sit outside of any if's, loops or case's? */
5376 IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
5380 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
5382 *pstring = ctx.as_string.data;
5384 o_free_unsafe(&ctx.as_string);
5387 debug_printf_parse("parse_stream return %p: "
5388 "end_trigger char found\n",
5390 return ctx.list_head;
5398 next = i_peek(input);
5401 /* Catch <, > before deciding whether this word is
5402 * an assignment. a=1 2>z b=2: b=2 is still assignment */
5405 redir_fd = redirect_opt_num(&dest);
5406 if (done_word(&dest, &ctx)) {
5409 redir_style = REDIRECT_OVERWRITE;
5411 redir_style = REDIRECT_APPEND;
5412 ch = i_getch(input);
5413 nommu_addchr(&ctx.as_string, ch);
5416 else if (next == '(') {
5417 syntax_error(">(process) not supported");
5421 if (parse_redirect(&ctx, redir_fd, redir_style, input))
5423 continue; /* back to top of while (1) */
5425 redir_fd = redirect_opt_num(&dest);
5426 if (done_word(&dest, &ctx)) {
5429 redir_style = REDIRECT_INPUT;
5431 redir_style = REDIRECT_HEREDOC;
5433 debug_printf_parse("++heredoc_cnt=%d\n", heredoc_cnt);
5434 ch = i_getch(input);
5435 nommu_addchr(&ctx.as_string, ch);
5436 } else if (next == '>') {
5437 redir_style = REDIRECT_IO;
5438 ch = i_getch(input);
5439 nommu_addchr(&ctx.as_string, ch);
5442 else if (next == '(') {
5443 syntax_error("<(process) not supported");
5447 if (parse_redirect(&ctx, redir_fd, redir_style, input))
5449 continue; /* back to top of while (1) */
5452 if (dest.o_assignment == MAYBE_ASSIGNMENT
5453 /* check that we are not in word in "a=1 2>word b=1": */
5454 && !ctx.pending_redirect
5456 /* ch is a special char and thus this word
5457 * cannot be an assignment */
5458 dest.o_assignment = NOT_ASSIGNMENT;
5463 if (dest.length == 0) {
5466 if (ch == EOF || ch == '\n')
5469 /* note: we do not add it to &ctx.as_string */
5471 nommu_addchr(&ctx.as_string, '\n');
5473 o_addQchr(&dest, ch);
5478 syntax_error("\\<eof>");
5481 o_addchr(&dest, '\\');
5482 ch = i_getch(input);
5483 nommu_addchr(&ctx.as_string, ch);
5484 o_addchr(&dest, ch);
5485 /* Example: echo Hello \2>file
5486 * we need to know that word 2 is quoted */
5490 if (handle_dollar(&ctx.as_string, &dest, input) != 0) {
5491 debug_printf_parse("parse_stream parse error: "
5492 "handle_dollar returned non-0\n");
5499 ch = i_getch(input);
5501 syntax_error_unterm_ch('\'');
5502 /*xfunc_die(); - redundant */
5504 nommu_addchr(&ctx.as_string, ch);
5507 if (dest.o_assignment == NOT_ASSIGNMENT)
5508 o_addqchr(&dest, ch);
5510 o_addchr(&dest, ch);
5515 is_in_dquote ^= 1; /* invert */
5516 if (dest.o_assignment == NOT_ASSIGNMENT)
5519 #if ENABLE_HUSH_TICK
5524 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
5525 o_addchr(&dest, '`');
5529 add_till_backquote(&dest, input);
5531 o_addstr(&ctx.as_string, dest.data + pos);
5532 o_addchr(&ctx.as_string, '`');
5534 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
5535 //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos);
5540 #if ENABLE_HUSH_CASE
5543 if (done_word(&dest, &ctx)) {
5546 done_pipe(&ctx, PIPE_SEQ);
5547 #if ENABLE_HUSH_CASE
5548 /* Eat multiple semicolons, detect
5549 * whether it means something special */
5554 ch = i_getch(input);
5555 nommu_addchr(&ctx.as_string, ch);
5556 if (ctx.ctx_res_w == RES_CASEI) {
5557 ctx.ctx_dsemicolon = 1;
5558 ctx.ctx_res_w = RES_MATCH;
5564 /* We just finished a cmd. New one may start
5565 * with an assignment */
5566 dest.o_assignment = MAYBE_ASSIGNMENT;
5569 if (done_word(&dest, &ctx)) {
5573 ch = i_getch(input);
5574 nommu_addchr(&ctx.as_string, ch);
5575 done_pipe(&ctx, PIPE_AND);
5577 done_pipe(&ctx, PIPE_BG);
5581 if (done_word(&dest, &ctx)) {
5584 #if ENABLE_HUSH_CASE
5585 if (ctx.ctx_res_w == RES_MATCH)
5586 break; /* we are in case's "word | word)" */
5588 if (next == '|') { /* || */
5589 ch = i_getch(input);
5590 nommu_addchr(&ctx.as_string, ch);
5591 done_pipe(&ctx, PIPE_OR);
5593 /* we could pick up a file descriptor choice here
5594 * with redirect_opt_num(), but bash doesn't do it.
5595 * "echo foo 2| cat" yields "foo 2". */
5600 #if ENABLE_HUSH_CASE
5601 /* "case... in [(]word)..." - skip '(' */
5602 if (ctx.ctx_res_w == RES_MATCH
5603 && ctx.command->argv == NULL /* not (word|(... */
5604 && dest.length == 0 /* not word(... */
5605 && dest.o_quoted == 0 /* not ""(... */
5611 if (parse_group(&dest, &ctx, input, ch) != 0) {
5616 #if ENABLE_HUSH_CASE
5617 if (ctx.ctx_res_w == RES_MATCH)
5621 /* proper use of this character is caught by end_trigger:
5622 * if we see {, we call parse_group(..., end_trigger='}')
5623 * and it will match } earlier (not here). */
5624 syntax_error_unexpected_ch(ch);
5628 bb_error_msg_and_die("BUG: unexpected %c\n", ch);
5634 struct parse_context *pctx;
5635 IF_HAS_KEYWORDS(struct parse_context *p2;)
5637 /* Clean up allocated tree.
5638 * Samples for finding leaks on syntax error recovery path.
5639 * Run them from interactive shell, watch pmap `pidof hush`.
5640 * while if false; then false; fi do break; done
5642 * while if false; then false; fi; do break; fi
5643 * Samples to catch leaks at execution:
5644 * while if (true | {true;}); then echo ok; fi; do break; done
5645 * while if (true | {true;}); then echo ok; fi; do (if echo ok; break; then :; fi) | cat; break; done
5649 /* Update pipe/command counts,
5650 * otherwise freeing may miss some */
5651 done_pipe(pctx, PIPE_SEQ);
5652 debug_printf_clean("freeing list %p from ctx %p\n",
5653 pctx->list_head, pctx);
5654 debug_print_tree(pctx->list_head, 0);
5655 free_pipe_list(pctx->list_head);
5656 debug_printf_clean("freed list %p\n", pctx->list_head);
5658 o_free_unsafe(&pctx->as_string);
5660 IF_HAS_KEYWORDS(p2 = pctx->stack;)
5664 IF_HAS_KEYWORDS(pctx = p2;)
5665 } while (HAS_KEYWORDS && pctx);
5666 /* Free text, clear all dest fields */
5668 /* If we are not in top-level parse, we return,
5669 * our caller will propagate error.
5671 if (end_trigger != ';') {
5679 /* Discard cached input, force prompt */
5681 USE_HUSH_INTERACTIVE(input->promptme = 1;)
5686 /* Executing from string: eval, sh -c '...'
5687 * or from file: /etc/profile, . file, sh <script>, sh (intereactive)
5688 * end_trigger controls how often we stop parsing
5689 * NUL: parse all, execute, return
5690 * ';': parse till ';' or newline, execute, repeat till EOF
5692 static void parse_and_run_stream(struct in_str *inp, int end_trigger)
5695 struct pipe *pipe_list;
5697 pipe_list = parse_stream(NULL, inp, end_trigger);
5698 if (!pipe_list) /* EOF */
5700 debug_print_tree(pipe_list, 0);
5701 debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
5702 run_and_free_list(pipe_list);
5706 static void parse_and_run_string(const char *s)
5708 struct in_str input;
5709 setup_string_in_str(&input, s);
5710 parse_and_run_stream(&input, '\0');
5713 static void parse_and_run_file(FILE *f)
5715 struct in_str input;
5716 setup_file_in_str(&input, f);
5717 parse_and_run_stream(&input, ';');
5720 /* Called a few times only (or even once if "sh -c") */
5721 static void block_signals(int second_time)
5726 mask = (1 << SIGQUIT);
5727 if (G_interactive_fd) {
5731 //TODO | (1 << SIGHUP)
5733 | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
5738 G.non_DFL_mask = mask;
5741 sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
5745 sigaddset(&G.blocked_set, sig);
5749 sigdelset(&G.blocked_set, SIGCHLD);
5751 sigprocmask(SIG_SETMASK, &G.blocked_set,
5752 second_time ? NULL : &G.inherited_set);
5753 /* POSIX allows shell to re-enable SIGCHLD
5754 * even if it was SIG_IGN on entry */
5755 // G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
5757 signal(SIGCHLD, SIG_DFL); // SIGCHLD_handler);
5762 static void maybe_set_to_sigexit(int sig)
5764 void (*handler)(int);
5765 /* non_DFL_mask'ed signals are, well, masked,
5766 * no need to set handler for them.
5768 if (!((G.non_DFL_mask >> sig) & 1)) {
5769 handler = signal(sig, sigexit);
5770 if (handler == SIG_IGN) /* oops... restore back to IGN! */
5771 signal(sig, handler);
5774 /* Set handlers to restore tty pgrp and exit */
5775 static void set_fatal_handlers(void)
5777 /* We _must_ restore tty pgrp on fatal signals */
5779 maybe_set_to_sigexit(SIGILL );
5780 maybe_set_to_sigexit(SIGFPE );
5781 maybe_set_to_sigexit(SIGBUS );
5782 maybe_set_to_sigexit(SIGSEGV);
5783 maybe_set_to_sigexit(SIGTRAP);
5784 } /* else: hush is perfect. what SEGV? */
5785 maybe_set_to_sigexit(SIGABRT);
5786 /* bash 3.2 seems to handle these just like 'fatal' ones */
5787 maybe_set_to_sigexit(SIGPIPE);
5788 maybe_set_to_sigexit(SIGALRM);
5789 //TODO: disable and move down when proper SIGHUP handling is added
5790 maybe_set_to_sigexit(SIGHUP );
5791 /* if we are interactive, [SIGHUP,] SIGTERM and SIGINT are masked.
5792 * if we aren't interactive... but in this case
5793 * we never want to restore pgrp on exit, and this fn is not called */
5794 /*maybe_set_to_sigexit(SIGTERM);*/
5795 /*maybe_set_to_sigexit(SIGINT );*/
5799 static int set_mode(const char cstate, const char mode)
5801 int state = (cstate == '-' ? 1 : 0);
5803 case 'n': G.fake_mode = state; break;
5804 case 'x': /*G.debug_mode = state;*/ break;
5805 default: return EXIT_FAILURE;
5807 return EXIT_SUCCESS;
5810 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5811 int hush_main(int argc, char **argv)
5813 static const struct variable const_shell_ver = {
5815 .varstr = (char*)hush_version_str,
5816 .max_len = 1, /* 0 can provoke free(name) */
5820 int signal_mask_is_inited = 0;
5823 struct variable *cur_var;
5826 if (EXIT_SUCCESS) /* if EXIT_SUCCESS == 0, is already done */
5827 G.last_exitcode = EXIT_SUCCESS;
5829 G.argv0_for_re_execing = argv[0];
5831 /* Deal with HUSH_VERSION */
5832 G.shell_ver = const_shell_ver; /* copying struct here */
5833 G.top_var = &G.shell_ver;
5834 debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
5835 unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
5836 /* Initialize our shell local variables with the values
5837 * currently living in the environment */
5838 cur_var = G.top_var;
5841 char *value = strchr(*e, '=');
5842 if (value) { /* paranoia */
5843 cur_var->next = xzalloc(sizeof(*cur_var));
5844 cur_var = cur_var->next;
5845 cur_var->varstr = *e;
5846 cur_var->max_len = strlen(*e);
5847 cur_var->flg_export = 1;
5851 debug_printf_env("putenv '%s'\n", hush_version_str);
5852 putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
5853 #if ENABLE_FEATURE_EDITING
5854 G.line_input_state = new_line_input_t(FOR_SHELL);
5856 G.global_argc = argc;
5857 G.global_argv = argv;
5858 /* Initialize some more globals to non-zero values */
5860 #if ENABLE_HUSH_INTERACTIVE
5861 if (ENABLE_FEATURE_EDITING)
5862 cmdedit_set_initial_prompt();
5866 if (setjmp(die_jmp)) {
5867 /* xfunc has failed! die die die */
5868 /* no EXIT traps, this is an escape hatch! */
5870 hush_exit(xfunc_error_retval);
5873 /* Shell is non-interactive at first. We need to call
5874 * block_signals(0) if we are going to execute "sh <script>",
5875 * "sh -c <cmds>" or login shell's /etc/profile and friends.
5876 * If we later decide that we are interactive, we run block_signals(0)
5877 * (or re-run block_signals(1) if we ran block_signals(0) before)
5878 * in order to intercept (more) signals.
5882 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
5884 opt = getopt(argc, argv, "c:xins"
5887 # if ENABLE_HUSH_FUNCTIONS
5897 G.root_pid = getpid();
5898 G.global_argv = argv + optind;
5899 if (!argv[optind]) {
5900 /* -c 'script' (no params): prevent empty $0 */
5901 *--G.global_argv = argv[0];
5903 } /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
5904 G.global_argc = argc - optind;
5905 block_signals(0); /* 0: called 1st time */
5906 parse_and_run_string(optarg);
5909 /* Well, we cannot just declare interactiveness,
5910 * we have to have some stuff (ctty, etc) */
5911 /* G_interactive_fd++; */
5914 /* "-s" means "read from stdin", but this is how we always
5915 * operate, so simply do nothing here. */
5918 case '<': /* "big heredoc" support */
5919 full_write(STDOUT_FILENO, optarg, strlen(optarg));
5922 G.root_pid = bb_strtou(optarg, &optarg, 16);
5924 G.last_bg_pid = bb_strtou(optarg, &optarg, 16);
5926 G.last_exitcode = bb_strtou(optarg, &optarg, 16);
5927 # if ENABLE_HUSH_LOOPS
5929 G.depth_of_loop = bb_strtou(optarg, &optarg, 16);
5934 set_local_var(xstrdup(optarg), 0, opt == 'R');
5936 # if ENABLE_HUSH_FUNCTIONS
5938 struct function *funcp = new_function(optarg);
5939 /* funcp->name is already set to optarg */
5940 /* funcp->body is set to NULL. It's a special case. */
5941 funcp->body_as_string = argv[optind];
5949 if (!set_mode('-', opt))
5953 fprintf(stderr, "Usage: sh [FILE]...\n"
5954 " or: sh -c command [args]...\n\n");
5960 } /* option parsing loop */
5963 G.root_pid = getpid();
5965 /* If we are login shell... */
5966 if (argv[0] && argv[0][0] == '-') {
5968 /* XXX what should argv be while sourcing /etc/profile? */
5969 debug_printf("sourcing /etc/profile\n");
5970 input = fopen_for_read("/etc/profile");
5971 if (input != NULL) {
5972 close_on_exec_on(fileno(input));
5973 block_signals(0); /* 0: called 1st time */
5974 signal_mask_is_inited = 1;
5975 parse_and_run_file(input);
5978 /* bash: after sourcing /etc/profile,
5979 * tries to source (in the given order):
5980 * ~/.bash_profile, ~/.bash_login, ~/.profile,
5981 * stopping of first found. --noprofile turns this off.
5982 * bash also sources ~/.bash_logout on exit.
5983 * If called as sh, skips .bash_XXX files.
5990 * "bash <script>" (which is never interactive (unless -i?))
5991 * sources $BASH_ENV here (without scanning $PATH).
5992 * If called as sh, does the same but with $ENV.
5994 debug_printf("running script '%s'\n", argv[optind]);
5995 G.global_argv = argv + optind;
5996 G.global_argc = argc - optind;
5997 input = xfopen_for_read(argv[optind]);
5998 close_on_exec_on(fileno(input));
5999 if (!signal_mask_is_inited)
6000 block_signals(0); /* 0: called 1st time */
6001 parse_and_run_file(input);
6002 #if ENABLE_FEATURE_CLEAN_UP
6008 /* Up to here, shell was non-interactive. Now it may become one.
6009 * NB: don't forget to (re)run block_signals(0/1) as needed.
6012 /* A shell is interactive if the '-i' flag was given, or if all of
6013 * the following conditions are met:
6015 * no arguments remaining or the -s flag given
6016 * standard input is a terminal
6017 * standard output is a terminal
6018 * Refer to Posix.2, the description of the 'sh' utility.
6021 if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
6022 G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
6023 debug_printf("saved_tty_pgrp:%d\n", G.saved_tty_pgrp);
6024 //TODO: "interactive" and "have job control" are two different things.
6025 //If tcgetpgrp fails here, "have job control" is false, but "interactive"
6026 //should stay on! Currently, we mix these into one.
6027 if (G.saved_tty_pgrp >= 0) {
6028 /* try to dup stdin to high fd#, >= 255 */
6029 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
6030 if (G_interactive_fd < 0) {
6031 /* try to dup to any fd */
6032 G_interactive_fd = dup(STDIN_FILENO);
6033 if (G_interactive_fd < 0)
6035 G_interactive_fd = 0;
6037 // TODO: track & disallow any attempts of user
6038 // to (inadvertently) close/redirect it
6041 debug_printf("interactive_fd:%d\n", G_interactive_fd);
6042 if (G_interactive_fd) {
6045 /* We are indeed interactive shell, and we will perform
6046 * job control. Setting up for that. */
6048 close_on_exec_on(G_interactive_fd);
6049 /* If we were run as 'hush &', sleep until we are
6050 * in the foreground (tty pgrp == our pgrp).
6051 * If we get started under a job aware app (like bash),
6052 * make sure we are now in charge so we don't fight over
6053 * who gets the foreground */
6055 shell_pgrp = getpgrp();
6056 G.saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
6057 if (G.saved_tty_pgrp == shell_pgrp)
6059 /* send TTIN to ourself (should stop us) */
6060 kill(- shell_pgrp, SIGTTIN);
6062 /* Block some signals */
6063 block_signals(signal_mask_is_inited);
6064 /* Set other signals to restore saved_tty_pgrp */
6065 set_fatal_handlers();
6066 /* Put ourselves in our own process group */
6067 bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
6068 /* Grab control of the terminal */
6069 tcsetpgrp(G_interactive_fd, getpid());
6070 /* -1 is special - makes xfuncs longjmp, not exit
6071 * (we reset die_sleep = 0 whereever we [v]fork) */
6072 enable_restore_tty_pgrp_on_exit(); /* sets die_sleep = -1 */
6073 } else if (!signal_mask_is_inited) {
6074 block_signals(0); /* 0: called 1st time */
6075 } /* else: block_signals(0) was done before */
6076 #elif ENABLE_HUSH_INTERACTIVE
6077 /* No job control compiled in, only prompt/line editing */
6078 if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
6079 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
6080 if (G_interactive_fd < 0) {
6081 /* try to dup to any fd */
6082 G_interactive_fd = dup(STDIN_FILENO);
6083 if (G_interactive_fd < 0)
6085 G_interactive_fd = 0;
6088 if (G_interactive_fd) {
6089 close_on_exec_on(G_interactive_fd);
6090 block_signals(signal_mask_is_inited);
6091 } else if (!signal_mask_is_inited) {
6095 /* We have interactiveness code disabled */
6096 if (!signal_mask_is_inited) {
6101 * if interactive but not a login shell, sources ~/.bashrc
6102 * (--norc turns this off, --rcfile <file> overrides)
6105 if (!ENABLE_FEATURE_SH_EXTRA_QUIET && G_interactive_fd) {
6106 printf("\n\n%s hush - the humble shell\n", bb_banner);
6107 printf("Enter 'help' for a list of built-in commands.\n\n");
6110 parse_and_run_file(stdin);
6113 #if ENABLE_FEATURE_CLEAN_UP
6114 if (G.cwd != bb_msg_unknown)
6116 cur_var = G.top_var->next;
6118 struct variable *tmp = cur_var;
6119 if (!cur_var->max_len)
6120 free(cur_var->varstr);
6121 cur_var = cur_var->next;
6125 hush_exit(G.last_exitcode);
6130 int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
6131 int lash_main(int argc, char **argv)
6133 //bb_error_msg("lash is deprecated, please use hush instead");
6134 return hush_main(argc, argv);
6142 static int builtin_trap(char **argv)
6149 G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
6153 /* No args: print all trapped. This isn't 100% correct as we
6154 * should be escaping the cmd so that it can be pasted back in
6156 for (i = 0; i < NSIG; ++i)
6158 printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
6159 return EXIT_SUCCESS;
6164 /* If first arg is decimal: reset all specified signals */
6165 sig = bb_strtou(*argv, NULL, 10);
6171 sig = get_signum(*argv++);
6172 if (sig < 0 || sig >= NSIG) {
6174 /* Mimic bash message exactly */
6175 bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
6180 G.traps[sig] = xstrdup(new_cmd);
6182 debug_printf("trap: setting SIG%s (%i) to '%s'",
6183 get_signame(sig), sig, G.traps[sig]);
6185 /* There is no signal for 0 (EXIT) */
6190 sigaddset(&G.blocked_set, sig);
6192 /* There was a trap handler, we are removing it
6193 * (if sig has non-DFL handling,
6194 * we don't need to do anything) */
6195 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
6197 sigdelset(&G.blocked_set, sig);
6199 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
6204 /* First arg is "-": reset all specified to default */
6205 /* First arg is "": ignore all specified */
6206 /* Everything else: execute first arg upon signal */
6208 bb_error_msg("trap: invalid arguments");
6209 return EXIT_FAILURE;
6211 if (NOT_LONE_DASH(*argv))
6217 static int builtin_true(char **argv UNUSED_PARAM)
6222 static int builtin_test(char **argv)
6229 return test_main(argc, argv - argc);
6232 static int builtin_echo(char **argv)
6239 return echo_main(argc, argv - argc);
6242 static int builtin_eval(char **argv)
6244 int rcode = EXIT_SUCCESS;
6247 char *str = expand_strvec_to_string(argv);
6249 * eval "echo Hi; done" ("done" is syntax error):
6250 * "echo Hi" will not execute too.
6252 parse_and_run_string(str);
6254 rcode = G.last_exitcode;
6259 static int builtin_cd(char **argv)
6261 const char *newdir = argv[1];
6262 if (newdir == NULL) {
6263 /* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
6264 * bash says "bash: cd: HOME not set" and does nothing
6267 newdir = getenv("HOME") ? : "/";
6269 if (chdir(newdir)) {
6270 /* Mimic bash message exactly */
6271 bb_perror_msg("cd: %s", newdir);
6272 return EXIT_FAILURE;
6275 return EXIT_SUCCESS;
6278 static int builtin_exec(char **argv)
6280 if (*++argv == NULL)
6281 return EXIT_SUCCESS; /* bash does this */
6286 // FIXME: if exec fails, bash does NOT exit! We do...
6287 pseudo_exec_argv(&dummy, argv, 0, NULL);
6292 static int builtin_exit(char **argv)
6294 debug_printf_exec("%s()\n", __func__);
6295 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
6296 //puts("exit"); /* bash does it */
6297 // TODO: warn if we have background jobs: "There are stopped jobs"
6298 // On second consecutive 'exit', exit anyway.
6299 // perhaps use G.exiting = -1 as indicator "last cmd was exit"
6301 /* note: EXIT trap is run by hush_exit */
6302 if (*++argv == NULL)
6303 hush_exit(G.last_exitcode);
6304 /* mimic bash: exit 123abc == exit 255 + error msg */
6305 xfunc_error_retval = 255;
6306 /* bash: exit -2 == exit 254, no error msg */
6307 hush_exit(xatoi(*argv) & 0xff);
6310 static int builtin_export(char **argv)
6312 if (*++argv == NULL) {
6319 /* ash emits: export VAR='VAL'
6320 * bash: declare -x VAR="VAL"
6321 * we follow ash example */
6322 const char *s = *e++;
6323 const char *p = strchr(s, '=');
6325 if (!p) /* wtf? take next variable */
6328 printf("export %.*s", (int)(p - s) + 1, s);
6332 p = strchrnul(s, '\'');
6334 printf("'%.*s'", (int)(p - s), s);
6339 /* s points to '; print ''...'''" */
6341 do putchar('\''); while (*++s == '\'');
6349 return EXIT_SUCCESS;
6356 value = strchr(name, '=');
6358 /* They are exporting something without a =VALUE */
6359 struct variable *var;
6361 var = get_local_var(name);
6363 var->flg_export = 1;
6364 debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
6365 putenv(var->varstr);
6367 /* bash does not return an error when trying to export
6368 * an undefined variable. Do likewise. */
6371 set_local_var(xstrdup(name), 1, 0);
6374 return EXIT_SUCCESS;
6378 /* built-in 'fg' and 'bg' handler */
6379 static int builtin_fg_bg(char **argv)
6384 if (!G_interactive_fd)
6385 return EXIT_FAILURE;
6386 /* If they gave us no args, assume they want the last backgrounded task */
6388 for (pi = G.job_list; pi; pi = pi->next) {
6389 if (pi->jobid == G.last_jobid) {
6393 bb_error_msg("%s: no current job", argv[0]);
6394 return EXIT_FAILURE;
6396 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
6397 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
6398 return EXIT_FAILURE;
6400 for (pi = G.job_list; pi; pi = pi->next) {
6401 if (pi->jobid == jobnum) {
6405 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
6406 return EXIT_FAILURE;
6408 // TODO: bash prints a string representation
6409 // of job being foregrounded (like "sleep 1 | cat")
6410 if (argv[0][0] == 'f') {
6411 /* Put the job into the foreground. */
6412 tcsetpgrp(G_interactive_fd, pi->pgrp);
6415 /* Restart the processes in the job */
6416 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
6417 for (i = 0; i < pi->num_cmds; i++) {
6418 debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
6419 pi->cmds[i].is_stopped = 0;
6421 pi->stopped_cmds = 0;
6423 i = kill(- pi->pgrp, SIGCONT);
6425 if (errno == ESRCH) {
6426 delete_finished_bg_job(pi);
6427 return EXIT_SUCCESS;
6429 bb_perror_msg("kill (SIGCONT)");
6432 if (argv[0][0] == 'f') {
6434 return checkjobs_and_fg_shell(pi);
6436 return EXIT_SUCCESS;
6440 #if ENABLE_HUSH_HELP
6441 static int builtin_help(char **argv UNUSED_PARAM)
6443 const struct built_in_command *x;
6446 "Built-in commands:\n"
6447 "------------------\n");
6448 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
6449 printf("%s\t%s\n", x->cmd, x->descr);
6452 return EXIT_SUCCESS;
6457 static int builtin_jobs(char **argv UNUSED_PARAM)
6460 const char *status_string;
6462 for (job = G.job_list; job; job = job->next) {
6463 if (job->alive_cmds == job->stopped_cmds)
6464 status_string = "Stopped";
6466 status_string = "Running";
6468 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
6470 return EXIT_SUCCESS;
6475 static int builtin_memleak(char **argv UNUSED_PARAM)
6480 /* Crude attempt to find where "free memory" starts,
6481 * sans fragmentation. */
6483 l = (unsigned long)p;
6486 if (l < (unsigned long)p) l = (unsigned long)p;
6489 if (!G.memleak_value)
6490 G.memleak_value = l;
6492 l -= G.memleak_value;
6499 /* Exitcode is "how many kilobytes we leaked since 1st call" */
6504 static int builtin_pwd(char **argv UNUSED_PARAM)
6507 return EXIT_SUCCESS;
6510 static int builtin_read(char **argv)
6513 const char *name = "REPLY";
6517 /* bash (3.2.33(1)) bug: "read 0abcd" will execute,
6518 * and _after_ that_ it will complain */
6519 if (!is_well_formed_var_name(name, '\0')) {
6520 /* Mimic bash message */
6521 bb_error_msg("read: '%s': not a valid identifier", name);
6526 //TODO: bash unbackslashes input, splits words and puts them in argv[i]
6528 string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
6529 return set_local_var(string, 0, 0);
6532 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
6533 * built-in 'set' handler
6535 * set [-abCefhmnuvx] [-o option] [argument...]
6536 * set [+abCefhmnuvx] [+o option] [argument...]
6537 * set -- [argument...]
6540 * Implementations shall support the options in both their hyphen and
6541 * plus-sign forms. These options can also be specified as options to sh.
6543 * Write out all variables and their values: set
6544 * Set $1, $2, and $3 and set "$#" to 3: set c a b
6545 * Turn on the -x and -v options: set -xv
6546 * Unset all positional parameters: set --
6547 * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
6548 * Set the positional parameters to the expansion of x, even if x expands
6549 * with a leading '-' or '+': set -- $x
6551 * So far, we only support "set -- [argument...]" and some of the short names.
6553 static int builtin_set(char **argv)
6556 char **pp, **g_argv;
6557 char *arg = *++argv;
6561 for (e = G.top_var; e; e = e->next)
6563 return EXIT_SUCCESS;
6567 if (!strcmp(arg, "--")) {
6571 if (arg[0] != '+' && arg[0] != '-')
6573 for (n = 1; arg[n]; ++n)
6574 if (set_mode(arg[0], arg[n]))
6576 } while ((arg = *++argv) != NULL);
6577 /* Now argv[0] is 1st argument */
6580 return EXIT_SUCCESS;
6583 /* NB: G.global_argv[0] ($0) is never freed/changed */
6584 g_argv = G.global_argv;
6585 if (G.global_args_malloced) {
6591 G.global_args_malloced = 1;
6592 pp = xzalloc(sizeof(pp[0]) * 2);
6593 pp[0] = g_argv[0]; /* retain $0 */
6596 /* This realloc's G.global_argv */
6597 G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
6604 return EXIT_SUCCESS;
6606 /* Nothing known, so abort */
6608 bb_error_msg("set: %s: invalid option", arg);
6609 return EXIT_FAILURE;
6612 static int builtin_shift(char **argv)
6618 if (n >= 0 && n < G.global_argc) {
6619 if (G.global_args_malloced) {
6622 free(G.global_argv[m++]);
6625 memmove(&G.global_argv[1], &G.global_argv[n+1],
6626 G.global_argc * sizeof(G.global_argv[0]));
6627 return EXIT_SUCCESS;
6629 return EXIT_FAILURE;
6632 static int builtin_source(char **argv)
6636 if (*++argv == NULL)
6637 return EXIT_FAILURE;
6639 /* XXX search through $PATH is missing */
6640 input = fopen_or_warn(*argv, "r");
6642 /* bb_perror_msg("%s", *argv); - done by fopen_or_warn */
6643 return EXIT_FAILURE;
6645 close_on_exec_on(fileno(input));
6647 /* Now run the file */
6649 /* XXX argv and argc are broken; need to save old G.global_argv
6650 * (pointer only is OK!) on this stack frame,
6651 * set G.global_argv=argv+1, recurse, and restore. */
6652 parse_and_run_file(input);
6654 return G.last_exitcode;
6657 static int builtin_umask(char **argv)
6660 const char *arg = argv[1];
6662 //TODO: umask may take chmod-like symbolic masks
6663 new_umask = bb_strtou(arg, NULL, 8);
6665 //Message? bash examples:
6666 //bash: umask: 'q': invalid symbolic mode operator
6667 //bash: umask: 999: octal number out of range
6668 return EXIT_FAILURE;
6671 new_umask = umask(0);
6672 printf("%.3o\n", (unsigned) new_umask);
6673 /* fall through and restore new_umask which we set to 0 */
6676 return EXIT_SUCCESS;
6679 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
6680 static int builtin_unset(char **argv)
6686 return EXIT_SUCCESS;
6689 if (argv[0][0] == '-') {
6690 switch (argv[0][1]) {
6696 bb_error_msg("unset: %s: invalid option", *argv);
6697 return EXIT_FAILURE;
6699 //TODO: disallow "unset -vf ..." too
6706 if (unset_local_var(*argv)) {
6707 /* unset <nonexistent_var> doesn't fail.
6708 * Error is when one tries to unset RO var.
6709 * Message was printed by unset_local_var. */
6713 //#if ENABLE_HUSH_FUNCTIONS
6715 // unset_local_func(*argv);
6723 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
6724 static int builtin_wait(char **argv)
6726 int ret = EXIT_SUCCESS;
6729 if (*++argv == NULL) {
6730 /* Don't care about wait results */
6731 /* Note 1: must wait until there are no more children */
6732 /* Note 2: must be interruptible */
6734 * $ sleep 3 & sleep 6 & wait
6739 * $ sleep 3 & sleep 6 & wait
6743 * ^C <-- after ~4 sec from keyboard
6746 sigaddset(&G.blocked_set, SIGCHLD);
6747 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
6750 if (errno == ECHILD)
6752 /* Wait for SIGCHLD or any other signal of interest */
6753 /* sigtimedwait with infinite timeout: */
6754 sig = sigwaitinfo(&G.blocked_set, NULL);
6756 sig = check_and_run_traps(sig);
6757 if (sig && sig != SIGCHLD) { /* see note 2 */
6763 sigdelset(&G.blocked_set, SIGCHLD);
6764 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
6768 /* This is probably buggy wrt interruptible-ness */
6770 pid_t pid = bb_strtou(*argv, NULL, 10);
6772 /* mimic bash message */
6773 bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
6774 return EXIT_FAILURE;
6776 if (waitpid(pid, &status, 0) == pid) {
6777 if (WIFSIGNALED(status))
6778 ret = 128 + WTERMSIG(status);
6779 else if (WIFEXITED(status))
6780 ret = WEXITSTATUS(status);
6784 bb_perror_msg("wait %s", *argv);
6793 #if ENABLE_HUSH_LOOPS
6794 static int builtin_break(char **argv)
6796 if (G.depth_of_loop == 0) {
6797 bb_error_msg("%s: only meaningful in a loop", argv[0]);
6798 return EXIT_SUCCESS; /* bash compat */
6800 G.flag_break_continue++; /* BC_BREAK = 1 */
6801 G.depth_break_continue = 1;
6803 G.depth_break_continue = bb_strtou(argv[1], NULL, 10);
6804 if (errno || !G.depth_break_continue || argv[2]) {
6805 bb_error_msg("%s: bad arguments", argv[0]);
6806 G.flag_break_continue = BC_BREAK;
6807 G.depth_break_continue = UINT_MAX;
6810 if (G.depth_of_loop < G.depth_break_continue)
6811 G.depth_break_continue = G.depth_of_loop;
6812 return EXIT_SUCCESS;
6815 static int builtin_continue(char **argv)
6817 G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
6818 return builtin_break(argv);