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>
11 * The parser routines proper are all original material, first
12 * written Dec 2000 and Jan 2001 by Larry Doolittle. The
13 * execution engine, the builtins, and much of the underlying
14 * support has been adapted from busybox-0.49pre's lash, which is
15 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
16 * written by Erik Andersen <andersen@codepoet.org>. That, in turn,
17 * is based in part on ladsh.c, by Michael K. Johnson and Erik W.
18 * Troan, which they placed in the public domain. I don't know
19 * how much of the Johnson/Troan code has survived the repeated
23 * o_addchr() derived from similar w_addchar function in glibc-2.2.
24 * setup_redirect(), redirect_opt_num(), and big chunks of main()
25 * and many builtins derived from contributions by Erik Andersen.
26 * Miscellaneous bugfixes from Matt Kraai.
28 * There are two big (and related) architecture differences between
29 * this parser and the lash parser. One is that this version is
30 * actually designed from the ground up to understand nearly all
31 * of the Bourne grammar. The second, consequential change is that
32 * the parser and input reader have been turned inside out. Now,
33 * the parser is in control, and asks for input as needed. The old
34 * way had the input reader in control, and it asked for parsing to
35 * take place as needed. The new way makes it much easier to properly
36 * handle the recursion implicit in the various substitutions, especially
37 * across continuation lines.
39 * POSIX syntax not implemented:
41 * <(list) and >(list) Process Substitution
42 * Here Documents ( << word )
45 * Parameter Expansion for substring processing ${var#word} ${var%word}
47 * Bash stuff maybe optional enable:
48 * &> and >& redirection of stdout+stderr
50 * reserved words: [[ ]] function select
51 * substrings ${var:1:5}
54 * job handling woefully incomplete and buggy (improved --vda)
56 * port selected bugfixes from post-0.49 busybox lash - done?
57 * change { and } from special chars to reserved words
58 * builtins: return, trap, ulimit
59 * test magic exec with redirection only
60 * follow IFS rules more precisely, including update semantics
61 * figure out what to do with backslash-newline
62 * propagate syntax errors, die on resource errors?
63 * continuation lines, both explicit and implicit - done?
65 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
68 #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */
69 //TODO: pull in some .h and find out whether we have SINGLE_APPLET_MAIN?
70 //#include "applet_tables.h" doesn't work
72 /* #include <dmalloc.h> */
78 #ifdef WANT_TO_TEST_NOMMU
83 # define USE_FOR_NOMMU(...) __VA_ARGS__
84 # define USE_FOR_MMU(...)
87 #if defined SINGLE_APPLET_MAIN
88 /* STANDALONE does not make sense, and won't compile */
89 #undef CONFIG_FEATURE_SH_STANDALONE
90 #undef ENABLE_FEATURE_SH_STANDALONE
91 #undef USE_FEATURE_SH_STANDALONE
92 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
93 #define ENABLE_FEATURE_SH_STANDALONE 0
94 #define USE_FEATURE_SH_STANDALONE(...)
95 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
98 #if !ENABLE_HUSH_INTERACTIVE
99 #undef ENABLE_FEATURE_EDITING
100 #define ENABLE_FEATURE_EDITING 0
101 #undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
102 #define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
105 /* Do we support ANY keywords? */
106 #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
107 #define HAS_KEYWORDS 1
108 #define IF_HAS_KEYWORDS(...) __VA_ARGS__
109 #define IF_HAS_NO_KEYWORDS(...)
111 #define HAS_KEYWORDS 0
112 #define IF_HAS_KEYWORDS(...)
113 #define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__
116 /* Keep unconditionally on for now */
119 #define ENABLE_HUSH_FUNCTIONS 0
122 /* If you comment out one of these below, it will be #defined later
123 * to perform debug printfs to stderr: */
124 #define debug_printf(...) do {} while (0)
125 /* Finer-grained debug switches */
126 #define debug_printf_parse(...) do {} while (0)
127 #define debug_print_tree(a, b) do {} while (0)
128 #define debug_printf_exec(...) do {} while (0)
129 #define debug_printf_env(...) do {} while (0)
130 #define debug_printf_jobs(...) do {} while (0)
131 #define debug_printf_expand(...) do {} while (0)
132 #define debug_printf_glob(...) do {} while (0)
133 #define debug_printf_list(...) do {} while (0)
134 #define debug_printf_subst(...) do {} while (0)
135 #define debug_printf_clean(...) do {} while (0)
138 #define debug_printf(...) fprintf(stderr, __VA_ARGS__)
141 #ifndef debug_printf_parse
142 #define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__)
145 #ifndef debug_printf_exec
146 #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__)
149 #ifndef debug_printf_env
150 #define debug_printf_env(...) fprintf(stderr, __VA_ARGS__)
153 #ifndef debug_printf_jobs
154 #define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__)
160 #ifndef debug_printf_expand
161 #define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__)
162 #define DEBUG_EXPAND 1
164 #define DEBUG_EXPAND 0
167 #ifndef debug_printf_glob
168 #define debug_printf_glob(...) fprintf(stderr, __VA_ARGS__)
174 #ifndef debug_printf_list
175 #define debug_printf_list(...) fprintf(stderr, __VA_ARGS__)
178 #ifndef debug_printf_subst
179 #define debug_printf_subst(...) fprintf(stderr, __VA_ARGS__)
182 #ifndef debug_printf_clean
183 /* broken, of course, but OK for testing */
184 static const char *indenter(int i)
186 static const char blanks[] ALIGN1 =
188 return &blanks[sizeof(blanks) - i - 1];
190 #define debug_printf_clean(...) fprintf(stderr, __VA_ARGS__)
191 #define DEBUG_CLEAN 1
193 #define DEBUG_CLEAN 0
197 static void debug_print_strings(const char *prefix, char **vv)
199 fprintf(stderr, "%s:\n", prefix);
201 fprintf(stderr, " '%s'\n", *vv++);
204 #define debug_print_strings(prefix, vv) ((void)0)
208 * Leak hunting. Use hush_leaktool.sh for post-processing.
210 #ifdef FOR_HUSH_LEAKTOOL
211 static void *xxmalloc(int lineno, size_t size)
213 void *ptr = xmalloc((size + 0xff) & ~0xff);
214 fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
217 static void *xxrealloc(int lineno, void *ptr, size_t size)
219 ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
220 fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
223 static char *xxstrdup(int lineno, const char *str)
225 char *ptr = xstrdup(str);
226 fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
229 static void xxfree(void *ptr)
231 fdprintf(2, "free %p\n", ptr);
234 #define xmalloc(s) xxmalloc(__LINE__, s)
235 #define xrealloc(p, s) xxrealloc(__LINE__, p, s)
236 #define xstrdup(s) xxstrdup(__LINE__, s)
237 #define free(p) xxfree(p)
241 #define ERR_PTR ((void*)(long)1)
243 static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="BB_VER;
245 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
247 #define SPECIAL_VAR_SYMBOL 3
249 typedef enum redir_type {
251 REDIRECT_OVERWRITE = 2,
257 /* The descrip member of this structure is only used to make
258 * debugging output pretty */
259 static const struct {
261 signed char default_fd;
265 { O_RDONLY, 0, "<" },
266 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
267 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
268 { O_RDONLY, -1, "<<" },
272 typedef enum pipe_style {
279 typedef enum reserved_style {
288 #if ENABLE_HUSH_LOOPS
295 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
300 /* two pseudo-keywords support contrived "case" syntax: */
301 RES_MATCH , /* "word)" */
302 RES_CASEI , /* "this command is inside CASE" */
309 typedef struct o_string {
311 int length; /* position where data is appended */
313 /* Protect newly added chars against globbing
314 * (by prepending \ to *, ?, [, \) */
318 smallint has_empty_slot;
319 smallint o_assignment; /* 0:maybe, 1:yes, 2:no */
322 MAYBE_ASSIGNMENT = 0,
323 DEFINITELY_ASSIGNMENT = 1,
325 WORD_IS_KEYWORD = 3, /* not assigment, but next word may be: "if v=xyz cmd;" */
327 /* Used for initialization: o_string foo = NULL_O_STRING; */
328 #define NULL_O_STRING { NULL }
330 /* I can almost use ordinary FILE*. Is open_memstream() universally
331 * available? Where is it documented? */
332 typedef struct in_str {
334 /* eof_flag=1: last char in ->p is really an EOF */
335 char eof_flag; /* meaningless if ->p == NULL */
337 #if ENABLE_HUSH_INTERACTIVE
339 smallint promptmode; /* 0: PS1, 1: PS2 */
342 int (*get) (struct in_str *);
343 int (*peek) (struct in_str *);
345 #define i_getch(input) ((input)->get(input))
346 #define i_peek(input) ((input)->peek(input))
348 struct redir_struct {
349 struct redir_struct *next;
350 char *rd_filename; /* filename */
351 int fd; /* file descriptor being redirected */
352 int dup; /* -1, or file descriptor being duplicated */
353 smallint /*enum redir_type*/ rd_type;
357 pid_t pid; /* 0 if exited */
358 int assignment_cnt; /* how many argv[i] are assignments? */
359 smallint is_stopped; /* is the command currently running? */
360 smallint grp_type; /* GRP_xxx */
361 struct pipe *group; /* if non-NULL, this "command" is { list },
362 * ( list ), or a compound statement */
364 char *group_as_string;
366 char **argv; /* command name and arguments */
367 struct redir_struct *redirects; /* I/O redirections */
369 /* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
370 * and on execution these are substituted with their values.
371 * Substitution can make _several_ words out of one argv[n]!
372 * Example: argv[0]=='.^C*^C.' here: echo .$*.
373 * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
376 #define GRP_SUBSHELL 1
377 #if ENABLE_HUSH_FUNCTIONS
378 #define GRP_FUNCTION 2
383 int num_cmds; /* total number of commands in job */
384 int alive_cmds; /* number of commands running (not exited) */
385 int stopped_cmds; /* number of commands alive, but stopped */
387 int jobid; /* job number */
388 pid_t pgrp; /* process group ID for the job */
389 char *cmdtext; /* name of job */
391 struct command *cmds; /* array of commands in pipe */
392 smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
393 IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */
394 IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */
397 /* This holds pointers to the various results of parsing */
398 struct parse_context {
399 /* linked list of pipes */
400 struct pipe *list_head;
401 /* last pipe (being constructed right now) */
403 /* last command in pipe (being constructed right now) */
404 struct command *command;
405 /* last redirect in command->redirects list */
406 struct redir_struct *pending_redirect;
412 smallint ctx_inverted; /* "! cmd | cmd" */
414 smallint ctx_dsemicolon; /* ";;" seen */
416 /* bitmask of FLAG_xxx, for figuring out valid reserved words */
418 /* group we are enclosed in:
419 * example: "if pipe1; pipe2; then pipe3; fi"
420 * when we see "if" or "then", we malloc and copy current context,
421 * and make ->stack point to it. then we parse pipeN.
422 * when closing "then" / fi" / whatever is found,
423 * we move list_head into ->stack->command->group,
424 * copy ->stack into current context, and delete ->stack.
425 * (parsing of { list } and ( list ) doesn't use this method)
427 struct parse_context *stack;
431 /* On program start, environ points to initial environment.
432 * putenv adds new pointers into it, unsetenv removes them.
433 * Neither of these (de)allocates the strings.
434 * setenv allocates new strings in malloc space and does putenv,
435 * and thus setenv is unusable (leaky) for shell's purposes */
436 #define setenv(...) setenv_is_leaky_dont_use()
438 struct variable *next;
439 char *varstr; /* points to "name=" portion */
440 int max_len; /* if > 0, name is part of initial env; else name is malloced */
441 smallint flg_export; /* putenv should be done on this var */
442 smallint flg_read_only;
451 /* "Globals" within this file */
452 /* Sorted roughly by size (smaller offsets == smaller code) */
454 #if ENABLE_HUSH_INTERACTIVE
455 /* 'interactive_fd' is a fd# open to ctty, if we have one
456 * _AND_ if we decided to act interactively */
460 #define G_interactive_fd (G.interactive_fd)
462 #define G_interactive_fd 0
464 #if ENABLE_FEATURE_EDITING
465 line_input_t *line_input_state;
471 pid_t saved_tty_pgrp;
473 struct pipe *job_list;
474 struct pipe *toplevel_list;
475 //// smallint ctrl_z_flag;
477 smallint flag_SIGINT;
478 #if ENABLE_HUSH_LOOPS
479 smallint flag_break_continue;
482 /* These four support $?, $#, and $1 */
483 smalluint last_return_code;
484 /* are global_argv and global_argv[1..n] malloced? (note: not [0]) */
485 smalluint global_args_malloced;
486 /* how many non-NULL argv's we have. NB: $# + 1 */
490 char *argv0_for_re_execing;
491 char **argv_from_re_execing;
493 #if ENABLE_HUSH_LOOPS
494 unsigned depth_break_continue;
495 unsigned depth_of_loop;
499 struct variable *top_var; /* = &G.shell_ver (set in main()) */
500 struct variable shell_ver;
501 /* Signal and trap handling */
502 // unsigned count_SIGCHLD;
503 // unsigned handled_SIGCHLD;
504 /* which signals have non-DFL handler (even with no traps set)? */
505 unsigned non_DFL_mask;
506 char **traps; /* char *traps[NSIG] */
507 sigset_t blocked_set;
508 sigset_t inherited_set;
509 char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
510 #if ENABLE_FEATURE_SH_STANDALONE
511 struct nofork_save_area nofork_save;
514 sigjmp_buf toplevel_jb;
517 #define G (*ptr_to_globals)
518 /* Not #defining name to G.name - this quickly gets unwieldy
519 * (too many defines). Also, I actually prefer to see when a variable
520 * is global, thus "G." prefix is a useful hint */
521 #define INIT_G() do { \
522 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
526 /* Function prototypes for builtins */
527 static int builtin_cd(char **argv);
528 static int builtin_echo(char **argv);
529 static int builtin_eval(char **argv);
530 static int builtin_exec(char **argv);
531 static int builtin_exit(char **argv);
532 static int builtin_export(char **argv);
534 static int builtin_fg_bg(char **argv);
535 static int builtin_jobs(char **argv);
538 static int builtin_help(char **argv);
540 static int builtin_pwd(char **argv);
541 static int builtin_read(char **argv);
542 static int builtin_test(char **argv);
543 static int builtin_trap(char **argv);
544 static int builtin_true(char **argv);
545 static int builtin_set(char **argv);
546 static int builtin_shift(char **argv);
547 static int builtin_source(char **argv);
548 static int builtin_umask(char **argv);
549 static int builtin_unset(char **argv);
550 static int builtin_wait(char **argv);
551 #if ENABLE_HUSH_LOOPS
552 static int builtin_break(char **argv);
553 static int builtin_continue(char **argv);
556 /* Table of built-in functions. They can be forked or not, depending on
557 * context: within pipes, they fork. As simple commands, they do not.
558 * When used in non-forking context, they can change global variables
559 * in the parent shell process. If forked, of course they cannot.
560 * For example, 'unset foo | whatever' will parse and run, but foo will
561 * still be set at the end. */
562 struct built_in_command {
564 int (*function)(char **argv);
567 #define BLTIN(cmd, func, help) { cmd, func, help }
569 #define BLTIN(cmd, func, help) { cmd, func }
573 /* For now, echo and test are unconditionally enabled.
574 * Maybe make it configurable? */
575 static const struct built_in_command bltins[] = {
576 BLTIN("." , builtin_source , "Run commands in a file"),
577 BLTIN(":" , builtin_true , "No-op"),
578 BLTIN("[" , builtin_test , "Test condition"),
580 BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
582 #if ENABLE_HUSH_LOOPS
583 BLTIN("break" , builtin_break , "Exit from a loop"),
585 BLTIN("cd" , builtin_cd , "Change directory"),
586 #if ENABLE_HUSH_LOOPS
587 BLTIN("continue", builtin_continue, "Start new loop iteration"),
589 BLTIN("echo" , builtin_echo , "Write to stdout"),
590 BLTIN("eval" , builtin_eval , "Construct and run shell command"),
591 BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
592 BLTIN("exit" , builtin_exit , "Exit"),
593 BLTIN("export" , builtin_export , "Set environment variable"),
595 BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
598 BLTIN("help" , builtin_help , "List shell built-in commands"),
601 BLTIN("jobs" , builtin_jobs , "List active jobs"),
603 BLTIN("pwd" , builtin_pwd , "Print current directory"),
604 BLTIN("read" , builtin_read , "Input environment variable"),
605 // BLTIN("return" , builtin_return , "Return from a function"),
606 BLTIN("set" , builtin_set , "Set/unset shell local variables"),
607 BLTIN("shift" , builtin_shift , "Shift positional parameters"),
608 BLTIN("test" , builtin_test , "Test condition"),
609 BLTIN("trap" , builtin_trap , "Trap signals"),
610 // BLTIN("ulimit" , builtin_return , "Control resource limits"),
611 BLTIN("umask" , builtin_umask , "Set file creation mask"),
612 BLTIN("unset" , builtin_unset , "Unset environment variable"),
613 BLTIN("wait" , builtin_wait , "Wait for process"),
617 static void maybe_die(const char *notice, const char *msg)
619 /* Was using fancy stuff:
620 * (G_interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...)
621 * but it SEGVs. ?! Oh well... explicit temp ptr works around that */
622 void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die;
623 #if ENABLE_HUSH_INTERACTIVE
624 if (G_interactive_fd)
627 fp(msg ? "%s: %s" : notice, notice, msg);
630 #define syntax(msg) maybe_die("syntax error", msg);
632 /* Debug -- trick gcc to expand __LINE__ and convert to string */
633 #define __syntax(msg, line) maybe_die("syntax error hush.c:" # line, msg)
634 #define _syntax(msg, line) __syntax(msg, line)
635 #define syntax(msg) _syntax(msg, __LINE__)
639 static int glob_needed(const char *s)
644 if (*s == '*' || *s == '[' || *s == '?')
651 static int is_assignment(const char *s)
653 if (!s || !(isalpha(*s) || *s == '_'))
656 while (isalnum(*s) || *s == '_')
661 /* Replace each \x with x in place, return ptr past NUL. */
662 static char *unbackslash(char *src)
668 if ((*dst++ = *src++) == '\0')
674 static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
695 v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
696 v[count1 + count2] = NULL;
699 v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
703 static char **add_string_to_strings(char **strings, char *add)
708 return add_strings_to_strings(strings, v, /*dup:*/ 0);
711 static void putenv_all(char **strings)
716 debug_printf_env("putenv '%s'\n", *strings);
721 static char **putenv_all_and_save_old(char **strings)
731 eq = strchr(*strings, '=');
734 v = getenv(*strings);
737 /* v points to VAL in VAR=VAL, go back to VAR */
738 v -= (eq - *strings) + 1;
739 old = add_string_to_strings(old, v);
748 static void free_strings_and_unsetenv(char **strings, int unset)
758 debug_printf_env("unsetenv '%s'\n", *v);
766 static void free_strings(char **strings)
768 free_strings_and_unsetenv(strings, 0);
772 /* Basic theory of signal handling in shell
773 * ========================================
774 * This does not describe what hush does, rather, it is current understanding
775 * what it _should_ do. If it doesn't, it's a bug.
776 * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
778 * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
779 * is finished or backgrounded. It is the same in interactive and
780 * non-interactive shells, and is the same regardless of whether
781 * a user trap handler is installed or a shell special one is in effect.
782 * ^C or ^Z from keyboard seem to execute "at once" because it usually
783 * backgrounds (i.e. stops) or kills all members of currently running
786 * Wait builtin in interruptible by signals for which user trap is set
787 * or by SIGINT in interactive shell.
789 * Trap handlers will execute even within trap handlers. (right?)
791 * User trap handlers are forgotten when subshell ("(cmd)") is entered. [TODO]
793 * If job control is off, backgrounded commands ("cmd &")
794 * have SIGINT, SIGQUIT set to SIG_IGN.
796 * Commands run in command substitution ("`cmd`")
797 * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
799 * Ordinary commands have signals set to SIG_IGN/DFL set as inherited
800 * by the shell from its parent.
802 * Siganls which differ from SIG_DFL action
803 * (note: child (i.e., [v]forked) shell is not an interactive shell):
806 * SIGTERM (interactive): ignore
807 * SIGHUP (interactive):
808 * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
809 * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
810 * (note that ^Z is handled not by trapping SIGTSTP, but by seeing
811 * that all pipe members are stopped) (right?)
812 * SIGINT (interactive): wait for last pipe, ignore the rest
813 * of the command line, show prompt. NB: ^C does not send SIGINT
814 * to interactive shell while shell is waiting for a pipe,
815 * since shell is bg'ed (is not in foreground process group).
816 * (check/expand this)
817 * Example 1: this waits 5 sec, but does not execute ls:
818 * "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
819 * Example 2: this does not wait and does not execute ls:
820 * "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
821 * Example 3: this does not wait 5 sec, but executes ls:
822 * "sleep 5; ls -l" + press ^C
824 * (What happens to signals which are IGN on shell start?)
825 * (What happens with signal mask on shell start?)
827 * Implementation in hush
828 * ======================
829 * We use in-kernel pending signal mask to determine which signals were sent.
830 * We block all signals which we don't want to take action immediately,
831 * i.e. we block all signals which need to have special handling as described
832 * above, and all signals which have traps set.
833 * After each pipe execution, we extract any pending signals via sigtimedwait()
836 * unsigned non_DFL_mask: a mask of such "special" signals
837 * sigset_t blocked_set: current blocked signal set
840 * clear bit in blocked_set unless it is also in non_DFL_mask
841 * "trap 'cmd' SIGxxx":
842 * set bit in blocked_set (even if 'cmd' is '')
843 * after [v]fork, if we plan to be a shell:
844 * nothing for {} child shell (say, "true | { true; true; } | true")
845 * unset all traps if () shell. [TODO]
846 * after [v]fork, if we plan to exec:
847 * POSIX says pending signal mask is cleared in child - no need to clear it.
848 * Restore blocked signal set to one inherited by shell just prior to exec.
850 * Note: as a result, we do not use signal handlers much. The only uses
851 * are to count SIGCHLDs [disabled - bug somewhere, + bloat]
852 * and to restore tty pgrp on signal-induced exit.
855 //static void SIGCHLD_handler(int sig UNUSED_PARAM)
857 // G.count_SIGCHLD++;
860 static int check_and_run_traps(int sig)
862 static const struct timespec zero_timespec = { 0, 0 };
863 smalluint save_rcode;
869 sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec);
874 if (G.traps && G.traps[sig]) {
875 if (G.traps[sig][0]) {
876 /* We have user-defined handler */
877 char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL };
878 save_rcode = G.last_return_code;
881 G.last_return_code = save_rcode;
882 } /* else: "" trap, ignoring signal */
885 /* not a trap: special action */
888 // G.count_SIGCHLD++;
897 default: /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
905 /* Restores tty foreground process group, and exits.
906 * May be called as signal handler for fatal signal
907 * (will faithfully resend signal to itself, producing correct exit state)
908 * or called directly with -EXITCODE.
909 * We also call it if xfunc is exiting. */
910 static void sigexit(int sig) NORETURN;
911 static void sigexit(int sig)
913 /* Disable all signals: job control, SIGPIPE, etc. */
914 sigprocmask_allsigs(SIG_BLOCK);
916 /* Careful: we can end up here after [v]fork. Do not restore
917 * tty pgrp then, only top-level shell process does that */
918 if (G_interactive_fd && getpid() == G.root_pid)
919 tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
921 /* Not a signal, just exit */
925 kill_myself_with_sig(sig); /* does not return */
929 /* Restores tty foreground process group, and exits. */
930 static void hush_exit(int exitcode) NORETURN;
931 static void hush_exit(int exitcode)
933 if (G.traps && G.traps[0] && G.traps[0][0]) {
934 char *argv[] = { NULL, xstrdup(G.traps[0]), NULL };
935 //TODO: do we need to prevent recursion?
941 fflush(NULL); /* flush all streams */
942 sigexit(- (exitcode & 0xff));
949 static const char *set_cwd(void)
951 /* xrealloc_getcwd_or_warn(arg) calls free(arg),
952 * we must not try to free(bb_msg_unknown) */
953 if (G.cwd == bb_msg_unknown)
955 G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
957 G.cwd = bb_msg_unknown;
962 /* Get/check local shell variables */
963 static struct variable *get_local_var(const char *name)
965 struct variable *cur;
971 for (cur = G.top_var; cur; cur = cur->next) {
972 if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
978 static const char *get_local_var_value(const char *src)
980 struct variable *var = get_local_var(src);
982 return strchr(var->varstr, '=') + 1;
986 /* str holds "NAME=VAL" and is expected to be malloced.
987 * We take ownership of it.
991 * -1: if NAME is set, leave export status alone
992 * if NAME is not set, do not export
993 * flg_read_only is set only when we handle -R var=val
996 #define set_local_var(str, flg_export, flg_read_only) \
997 set_local_var(str, flg_export)
999 static int set_local_var(char *str, int flg_export, int flg_read_only)
1001 struct variable *cur;
1005 value = strchr(str, '=');
1006 if (!value) { /* not expected to ever happen? */
1011 name_len = value - str + 1; /* including '=' */
1012 cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
1014 if (strncmp(cur->varstr, str, name_len) != 0) {
1016 /* Bail out. Note that now cur points
1017 * to last var in linked list */
1023 /* We found an existing var with this name */
1025 if (cur->flg_read_only) {
1029 bb_error_msg("%s: readonly variable", str);
1033 debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
1034 unsetenv(str); /* just in case */
1036 if (strcmp(cur->varstr, str) == 0) {
1041 if (cur->max_len >= strlen(str)) {
1042 /* This one is from startup env, reuse space */
1043 strcpy(cur->varstr, str);
1046 /* max_len == 0 signifies "malloced" var, which we can
1047 * (and has to) free */
1051 goto set_str_and_exp;
1054 /* Not found - create next variable struct */
1055 cur->next = xzalloc(sizeof(*cur));
1061 cur->flg_read_only = flg_read_only;
1064 if (flg_export == 1)
1065 cur->flg_export = 1;
1066 if (cur->flg_export) {
1067 debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
1068 return putenv(cur->varstr);
1073 static int unset_local_var(const char *name)
1075 struct variable *cur;
1076 struct variable *prev = prev; /* for gcc */
1080 return EXIT_SUCCESS;
1081 name_len = strlen(name);
1084 if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
1085 if (cur->flg_read_only) {
1086 bb_error_msg("%s: readonly variable", name);
1087 return EXIT_FAILURE;
1089 /* prev is ok to use here because 1st variable, HUSH_VERSION,
1090 * is ro, and we cannot reach this code on the 1st pass */
1091 prev->next = cur->next;
1092 debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
1093 bb_unsetenv(cur->varstr);
1097 return EXIT_SUCCESS;
1102 return EXIT_SUCCESS;
1105 #if ENABLE_SH_MATH_SUPPORT
1106 #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c)))
1107 #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c)))
1108 static char *endofname(const char *name)
1116 if (!is_in_name(*p))
1122 static void arith_set_local_var(const char *name, const char *val, int flags)
1124 /* arith code doesnt malloc space, so do it for it */
1125 char *var = xasprintf("%s=%s", name, val);
1126 set_local_var(var, flags, 0);
1134 static int static_get(struct in_str *i)
1143 static int static_peek(struct in_str *i)
1148 #if ENABLE_HUSH_INTERACTIVE
1150 static void cmdedit_set_initial_prompt(void)
1152 if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1153 G.PS1 = getenv("PS1");
1160 static const char* setup_prompt_string(int promptmode)
1162 const char *prompt_str;
1163 debug_printf("setup_prompt_string %d ", promptmode);
1164 if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1165 /* Set up the prompt */
1166 if (promptmode == 0) { /* PS1 */
1168 G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#');
1173 prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
1174 debug_printf("result '%s'\n", prompt_str);
1178 static void get_user_input(struct in_str *i)
1181 const char *prompt_str;
1183 prompt_str = setup_prompt_string(i->promptmode);
1184 #if ENABLE_FEATURE_EDITING
1185 /* Enable command line editing only while a command line
1186 * is actually being read */
1189 /* buglet: SIGINT will not make new prompt to appear _at once_,
1190 * only after <Enter>. (^C will work) */
1191 r = read_line_input(prompt_str, G.user_input_buf, BUFSIZ-1, G.line_input_state);
1192 /* catch *SIGINT* etc (^C is handled by read_line_input) */
1193 check_and_run_traps(0);
1194 } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */
1195 i->eof_flag = (r < 0);
1196 if (i->eof_flag) { /* EOF/error detected */
1197 G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
1198 G.user_input_buf[1] = '\0';
1203 fputs(prompt_str, stdout);
1205 G.user_input_buf[0] = r = fgetc(i->file);
1206 /*G.user_input_buf[1] = '\0'; - already is and never changed */
1207 //do we need check_and_run_traps(0)? (maybe only if stdin)
1208 } while (G.flag_SIGINT);
1209 i->eof_flag = (r == EOF);
1211 i->p = G.user_input_buf;
1214 #endif /* INTERACTIVE */
1216 /* This is the magic location that prints prompts
1217 * and gets data back from the user */
1218 static int file_get(struct in_str *i)
1222 /* If there is data waiting, eat it up */
1223 if (i->p && *i->p) {
1224 #if ENABLE_HUSH_INTERACTIVE
1228 if (i->eof_flag && !*i->p)
1230 /* note: ch is never NUL */
1232 /* need to double check i->file because we might be doing something
1233 * more complicated by now, like sourcing or substituting. */
1234 #if ENABLE_HUSH_INTERACTIVE
1235 if (G_interactive_fd && i->promptme && i->file == stdin) {
1238 } while (!*i->p); /* need non-empty line */
1239 i->promptmode = 1; /* PS2 */
1244 do ch = fgetc(i->file); while (ch == '\0');
1246 debug_printf("file_get: got '%c' %d\n", ch, ch);
1247 #if ENABLE_HUSH_INTERACTIVE
1254 /* All callers guarantee this routine will never
1255 * be used right after a newline, so prompting is not needed.
1257 static int file_peek(struct in_str *i)
1260 if (i->p && *i->p) {
1261 if (i->eof_flag && !i->p[1])
1264 /* note: ch is never NUL */
1266 do ch = fgetc(i->file); while (ch == '\0');
1267 i->eof_flag = (ch == EOF);
1268 i->peek_buf[0] = ch;
1269 i->peek_buf[1] = '\0';
1271 debug_printf("file_peek: got '%c' %d\n", ch, ch);
1275 static void setup_file_in_str(struct in_str *i, FILE *f)
1277 i->peek = file_peek;
1279 #if ENABLE_HUSH_INTERACTIVE
1281 i->promptmode = 0; /* PS1 */
1287 static void setup_string_in_str(struct in_str *i, const char *s)
1289 i->peek = static_peek;
1290 i->get = static_get;
1291 #if ENABLE_HUSH_INTERACTIVE
1293 i->promptmode = 0; /* PS1 */
1303 #define B_CHUNK (32 * sizeof(char*))
1305 static void o_reset(o_string *o)
1313 static void o_free(o_string *o)
1316 memset(o, 0, sizeof(*o));
1319 static ALWAYS_INLINE void o_free_unsafe(o_string *o)
1324 static void o_grow_by(o_string *o, int len)
1326 if (o->length + len > o->maxlen) {
1327 o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
1328 o->data = xrealloc(o->data, 1 + o->maxlen);
1332 static void o_addchr(o_string *o, int ch)
1334 debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
1336 o->data[o->length] = ch;
1338 o->data[o->length] = '\0';
1341 static void o_addblock(o_string *o, const char *str, int len)
1344 memcpy(&o->data[o->length], str, len);
1346 o->data[o->length] = '\0';
1350 static void o_addstr(o_string *o, const char *str)
1352 o_addblock(o, str, strlen(str));
1356 static void o_addstr_with_NUL(o_string *o, const char *str)
1358 o_addblock(o, str, strlen(str) + 1);
1361 static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
1366 && (*str != '*' && *str != '?' && *str != '[')
1374 /* My analysis of quoting semantics tells me that state information
1375 * is associated with a destination, not a source.
1377 static void o_addqchr(o_string *o, int ch)
1380 char *found = strchr("*?[\\", ch);
1385 o->data[o->length] = '\\';
1388 o->data[o->length] = ch;
1390 o->data[o->length] = '\0';
1393 static void o_addQchr(o_string *o, int ch)
1396 if (o->o_escape && strchr("*?[\\", ch)) {
1398 o->data[o->length] = '\\';
1402 o->data[o->length] = ch;
1404 o->data[o->length] = '\0';
1407 static void o_addQstr(o_string *o, const char *str, int len)
1410 o_addblock(o, str, len);
1416 int ordinary_cnt = strcspn(str, "*?[\\");
1417 if (ordinary_cnt > len) /* paranoia */
1419 o_addblock(o, str, ordinary_cnt);
1420 if (ordinary_cnt == len)
1422 str += ordinary_cnt;
1423 len -= ordinary_cnt + 1; /* we are processing + 1 char below */
1427 if (ch) { /* it is necessarily one of "*?[\\" */
1429 o->data[o->length] = '\\';
1433 o->data[o->length] = ch;
1435 o->data[o->length] = '\0';
1439 /* A special kind of o_string for $VAR and `cmd` expansion.
1440 * It contains char* list[] at the beginning, which is grown in 16 element
1441 * increments. Actual string data starts at the next multiple of 16 * (char*).
1442 * list[i] contains an INDEX (int!) into this string data.
1443 * It means that if list[] needs to grow, data needs to be moved higher up
1444 * but list[i]'s need not be modified.
1445 * NB: remembering how many list[i]'s you have there is crucial.
1446 * o_finalize_list() operation post-processes this structure - calculates
1447 * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
1449 #if DEBUG_EXPAND || DEBUG_GLOB
1450 static void debug_print_list(const char *prefix, o_string *o, int n)
1452 char **list = (char**)o->data;
1453 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1455 fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n",
1456 prefix, list, n, string_start, o->length, o->maxlen);
1458 fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i],
1459 o->data + (int)list[i] + string_start,
1460 o->data + (int)list[i] + string_start);
1464 const char *p = o->data + (int)list[n - 1] + string_start;
1465 fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
1469 #define debug_print_list(prefix, o, n) ((void)0)
1472 /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
1473 * in list[n] so that it points past last stored byte so far.
1474 * It returns n+1. */
1475 static int o_save_ptr_helper(o_string *o, int n)
1477 char **list = (char**)o->data;
1481 if (!o->has_empty_slot) {
1482 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1483 string_len = o->length - string_start;
1484 if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
1485 debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
1486 /* list[n] points to string_start, make space for 16 more pointers */
1487 o->maxlen += 0x10 * sizeof(list[0]);
1488 o->data = xrealloc(o->data, o->maxlen + 1);
1489 list = (char**)o->data;
1490 memmove(list + n + 0x10, list + n, string_len);
1491 o->length += 0x10 * sizeof(list[0]);
1493 debug_printf_list("list[%d]=%d string_start=%d\n",
1494 n, string_len, string_start);
1497 /* We have empty slot at list[n], reuse without growth */
1498 string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
1499 string_len = o->length - string_start;
1500 debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n",
1501 n, string_len, string_start);
1502 o->has_empty_slot = 0;
1504 list[n] = (char*)(ptrdiff_t)string_len;
1508 /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
1509 static int o_get_last_ptr(o_string *o, int n)
1511 char **list = (char**)o->data;
1512 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1514 return ((int)(ptrdiff_t)list[n-1]) + string_start;
1517 /* o_glob performs globbing on last list[], saving each result
1518 * as a new list[]. */
1519 static int o_glob(o_string *o, int n)
1525 debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
1527 return o_save_ptr_helper(o, n);
1528 pattern = o->data + o_get_last_ptr(o, n);
1529 debug_printf_glob("glob pattern '%s'\n", pattern);
1530 if (!glob_needed(pattern)) {
1532 o->length = unbackslash(pattern) - o->data;
1533 debug_printf_glob("glob pattern '%s' is literal\n", pattern);
1534 return o_save_ptr_helper(o, n);
1537 memset(&globdata, 0, sizeof(globdata));
1538 gr = glob(pattern, 0, NULL, &globdata);
1539 debug_printf_glob("glob('%s'):%d\n", pattern, gr);
1540 if (gr == GLOB_NOSPACE)
1541 bb_error_msg_and_die("out of memory during glob");
1542 if (gr == GLOB_NOMATCH) {
1543 globfree(&globdata);
1546 if (gr != 0) { /* GLOB_ABORTED ? */
1547 //TODO: testcase for bad glob pattern behavior
1548 bb_error_msg("glob(3) error %d on '%s'", gr, pattern);
1550 if (globdata.gl_pathv && globdata.gl_pathv[0]) {
1551 char **argv = globdata.gl_pathv;
1552 o->length = pattern - o->data; /* "forget" pattern */
1554 o_addstr_with_NUL(o, *argv);
1555 n = o_save_ptr_helper(o, n);
1561 globfree(&globdata);
1563 debug_print_list("o_glob returning", o, n);
1567 /* If o->o_glob == 1, glob the string so far remembered.
1568 * Otherwise, just finish current list[] and start new */
1569 static int o_save_ptr(o_string *o, int n)
1571 if (o->o_glob) { /* if globbing is requested */
1572 /* If o->has_empty_slot, list[n] was already globbed
1573 * (if it was requested back then when it was filled)
1574 * so don't do that again! */
1575 if (!o->has_empty_slot)
1576 return o_glob(o, n); /* o_save_ptr_helper is inside */
1578 return o_save_ptr_helper(o, n);
1581 /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
1582 static char **o_finalize_list(o_string *o, int n)
1587 n = o_save_ptr(o, n); /* force growth for list[n] if necessary */
1589 debug_print_list("finalized", o, n);
1590 debug_printf_expand("finalized n:%d\n", n);
1591 list = (char**)o->data;
1592 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1596 list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start;
1602 /* Expansion can recurse */
1603 #if ENABLE_HUSH_TICK
1604 static int process_command_subs(o_string *dest, const char *s);
1606 static char *expand_string_to_string(const char *str);
1608 #define parse_stream_dquoted(as_string, dest, input, dquote_end) \
1609 parse_stream_dquoted(dest, input, dquote_end)
1611 static int parse_stream_dquoted(o_string *as_string,
1613 struct in_str *input,
1616 /* expand_strvec_to_strvec() takes a list of strings, expands
1617 * all variable references within and returns a pointer to
1618 * a list of expanded strings, possibly with larger number
1619 * of strings. (Think VAR="a b"; echo $VAR).
1620 * This new list is allocated as a single malloc block.
1621 * NULL-terminated list of char* pointers is at the beginning of it,
1622 * followed by strings themself.
1623 * Caller can deallocate entire list by single free(list). */
1625 /* Store given string, finalizing the word and starting new one whenever
1626 * we encounter IFS char(s). This is used for expanding variable values.
1627 * End-of-string does NOT finalize word: think about 'echo -$VAR-' */
1628 static int expand_on_ifs(o_string *output, int n, const char *str)
1631 int word_len = strcspn(str, G.ifs);
1633 if (output->o_escape || !output->o_glob)
1634 o_addQstr(output, str, word_len);
1635 else /* protect backslashes against globbing up :) */
1636 o_addblock_duplicate_backslash(output, str, word_len);
1639 if (!*str) /* EOL - do not finalize word */
1641 o_addchr(output, '\0');
1642 debug_print_list("expand_on_ifs", output, n);
1643 n = o_save_ptr(output, n);
1644 str += strspn(str, G.ifs); /* skip ifs chars */
1646 debug_print_list("expand_on_ifs[1]", output, n);
1650 /* Expand all variable references in given string, adding words to list[]
1651 * at n, n+1,... positions. Return updated n (so that list[n] is next one
1652 * to be filled). This routine is extremely tricky: has to deal with
1653 * variables/parameters with whitespace, $* and $@, and constructs like
1654 * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
1655 static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
1657 /* or_mask is either 0 (normal case) or 0x80
1658 * (expansion of right-hand side of assignment == 1-element expand.
1659 * It will also do no globbing, and thus we must not backslash-quote!) */
1661 char first_ch, ored_ch;
1668 debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
1669 debug_print_list("expand_vars_to_list", output, n);
1670 n = o_save_ptr(output, n);
1671 debug_print_list("expand_vars_to_list[0]", output, n);
1673 while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
1674 #if ENABLE_HUSH_TICK
1675 o_string subst_result = NULL_O_STRING;
1677 #if ENABLE_SH_MATH_SUPPORT
1678 char arith_buf[sizeof(arith_t)*3 + 2];
1680 o_addblock(output, arg, p - arg);
1681 debug_print_list("expand_vars_to_list[1]", output, n);
1683 p = strchr(p, SPECIAL_VAR_SYMBOL);
1685 first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
1686 /* "$@" is special. Even if quoted, it can still
1687 * expand to nothing (not even an empty string) */
1688 if ((first_ch & 0x7f) != '@')
1689 ored_ch |= first_ch;
1692 switch (first_ch & 0x7f) {
1693 /* Highest bit in first_ch indicates that var is double-quoted */
1695 val = utoa(G.root_pid);
1697 case '!': /* bg pid */
1698 val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)"";
1700 case '?': /* exitcode */
1701 val = utoa(G.last_return_code);
1703 case '#': /* argc */
1704 if (arg[1] != SPECIAL_VAR_SYMBOL)
1705 /* actually, it's a ${#var} */
1707 val = utoa(G.global_argc ? G.global_argc-1 : 0);
1712 if (!G.global_argv[i])
1714 ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
1715 if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
1716 smallint sv = output->o_escape;
1717 /* unquoted var's contents should be globbed, so don't escape */
1718 output->o_escape = 0;
1719 while (G.global_argv[i]) {
1720 n = expand_on_ifs(output, n, G.global_argv[i]);
1721 debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
1722 if (G.global_argv[i++][0] && G.global_argv[i]) {
1723 /* this argv[] is not empty and not last:
1724 * put terminating NUL, start new word */
1725 o_addchr(output, '\0');
1726 debug_print_list("expand_vars_to_list[2]", output, n);
1727 n = o_save_ptr(output, n);
1728 debug_print_list("expand_vars_to_list[3]", output, n);
1731 output->o_escape = sv;
1733 /* If or_mask is nonzero, we handle assignment 'a=....$@.....'
1734 * and in this case should treat it like '$*' - see 'else...' below */
1735 if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */
1737 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1738 if (++i >= G.global_argc)
1740 o_addchr(output, '\0');
1741 debug_print_list("expand_vars_to_list[4]", output, n);
1742 n = o_save_ptr(output, n);
1744 } else { /* quoted $*: add as one word */
1746 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1747 if (!G.global_argv[++i])
1750 o_addchr(output, G.ifs[0]);
1754 case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
1755 /* "Empty variable", used to make "" etc to not disappear */
1759 #if ENABLE_HUSH_TICK
1760 case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
1763 //TODO: can we just stuff it into "output" directly?
1764 debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
1765 process_command_subs(&subst_result, arg);
1766 debug_printf_subst("SUBST RES '%s'\n", subst_result.data);
1767 val = subst_result.data;
1770 #if ENABLE_SH_MATH_SUPPORT
1771 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
1772 arith_eval_hooks_t hooks;
1777 arg++; /* skip '+' */
1778 *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
1779 debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
1781 /* Optional: skip expansion if expr is simple ("a + 3", "i++" etc) */
1784 unsigned char c = *exp_str++;
1791 if (strchr(" \t+-*/%_", c) != NULL)
1793 c |= 0x20; /* tolower */
1794 if (c >= 'a' && c <= 'z')
1798 /* We need to expand. Example: "echo $(($a + 1)) $((1 + $((2)) ))" */
1800 struct in_str input;
1801 o_string dest = NULL_O_STRING;
1803 setup_string_in_str(&input, arg);
1804 parse_stream_dquoted(NULL, &dest, &input, EOF);
1805 //bb_error_msg("'%s' -> '%s'", arg, dest.data);
1806 exp_str = expand_string_to_string(dest.data);
1807 //bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
1811 hooks.lookupvar = get_local_var_value;
1812 hooks.setvar = arith_set_local_var;
1813 hooks.endofname = endofname;
1814 res = arith(exp_str ? exp_str : arg, &errcode, &hooks);
1819 case -3: maybe_die("arith", "exponent less than 0"); break;
1820 case -2: maybe_die("arith", "divide by zero"); break;
1821 case -5: maybe_die("arith", "expression recursion loop detected"); break;
1822 default: maybe_die("arith", "syntax error"); break;
1825 debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
1826 sprintf(arith_buf, arith_t_fmt, res);
1831 default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
1833 bool exp_len = false;
1834 bool exp_null = false;
1836 char exp_save = exp_save; /* for compiler */
1837 char exp_op = exp_op; /* for compiler */
1838 char *exp_word = exp_word; /* for compiler */
1842 arg[0] = first_ch & 0x7f;
1844 /* prepare for expansions */
1845 if (var[0] == '#') {
1846 /* handle length expansion ${#var} */
1850 /* maybe handle parameter expansion */
1851 exp_off = strcspn(var, ":-=+?");
1855 exp_save = var[exp_off];
1856 exp_null = exp_save == ':';
1857 exp_word = var + exp_off;
1858 if (exp_null) ++exp_word;
1859 exp_op = *exp_word++;
1860 var[exp_off] = '\0';
1864 /* lookup the variable in question */
1865 if (isdigit(var[0])) {
1866 /* handle_dollar() should have vetted var for us */
1868 if (i < G.global_argc)
1869 val = G.global_argv[i];
1870 /* else val remains NULL: $N with too big N */
1872 val = get_local_var_value(var);
1874 /* handle any expansions */
1876 debug_printf_expand("expand: length of '%s' = ", val);
1877 val = utoa(val ? strlen(val) : 0);
1878 debug_printf_expand("%s\n", val);
1879 } else if (exp_off) {
1880 /* we need to do an expansion */
1881 int exp_test = (!val || (exp_null && !val[0]));
1883 exp_test = !exp_test;
1884 debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
1885 exp_null ? "true" : "false", exp_test);
1888 maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
1892 if (exp_op == '=') {
1893 if (isdigit(var[0]) || var[0] == '#') {
1894 maybe_die(var, "special vars cannot assign in this way");
1897 char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
1898 sprintf(new_var, "%s=%s", var, val);
1899 set_local_var(new_var, -1, 0);
1903 var[exp_off] = exp_save;
1907 #if ENABLE_HUSH_TICK
1910 if (!(first_ch & 0x80)) { /* unquoted $VAR */
1911 debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape);
1913 /* unquoted var's contents should be globbed, so don't escape */
1914 smallint sv = output->o_escape;
1915 output->o_escape = 0;
1916 n = expand_on_ifs(output, n, val);
1918 output->o_escape = sv;
1920 } else { /* quoted $VAR, val will be appended below */
1921 debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape);
1924 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
1926 o_addQstr(output, val, strlen(val));
1928 /* Do the check to avoid writing to a const string */
1929 if (*p != SPECIAL_VAR_SYMBOL)
1930 *p = SPECIAL_VAR_SYMBOL;
1932 #if ENABLE_HUSH_TICK
1933 o_free(&subst_result);
1936 } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
1939 debug_print_list("expand_vars_to_list[a]", output, n);
1940 /* this part is literal, and it was already pre-quoted
1941 * if needed (much earlier), do not use o_addQstr here! */
1942 o_addstr_with_NUL(output, arg);
1943 debug_print_list("expand_vars_to_list[b]", output, n);
1944 } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
1945 && !(ored_ch & 0x80) /* and all vars were not quoted. */
1948 /* allow to reuse list[n] later without re-growth */
1949 output->has_empty_slot = 1;
1951 o_addchr(output, '\0');
1956 static char **expand_variables(char **argv, int or_mask)
1961 o_string output = NULL_O_STRING;
1963 if (or_mask & 0x100) {
1964 output.o_escape = 1; /* protect against globbing for "$var" */
1965 /* (unquoted $var will temporarily switch it off) */
1972 n = expand_vars_to_list(&output, n, *v, (char)or_mask);
1975 debug_print_list("expand_variables", &output, n);
1977 /* output.data (malloced in one block) gets returned in "list" */
1978 list = o_finalize_list(&output, n);
1979 debug_print_strings("expand_variables[1]", list);
1983 static char **expand_strvec_to_strvec(char **argv)
1985 return expand_variables(argv, 0x100);
1988 /* Used for expansion of right hand of assignments */
1989 /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs
1991 static char *expand_string_to_string(const char *str)
1993 char *argv[2], **list;
1995 argv[0] = (char*)str;
1997 list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */
1999 if (!list[0] || list[1])
2000 bb_error_msg_and_die("BUG in varexp2");
2001 /* actually, just move string 2*sizeof(char*) bytes back */
2002 overlapping_strcpy((char*)list, list[0]);
2003 debug_printf_expand("string_to_string='%s'\n", (char*)list);
2007 /* Used for "eval" builtin */
2008 static char* expand_strvec_to_string(char **argv)
2012 list = expand_variables(argv, 0x80);
2013 /* Convert all NULs to spaces */
2018 if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
2019 bb_error_msg_and_die("BUG in varexp3");
2020 list[n][-1] = ' '; /* TODO: or to G.ifs[0]? */
2024 overlapping_strcpy((char*)list, list[0]);
2025 debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
2029 static char **expand_assignments(char **argv, int count)
2033 /* Expand assignments into one string each */
2034 for (i = 0; i < count; i++) {
2035 p = add_string_to_strings(p, expand_string_to_string(argv[i]));
2041 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
2042 * and stderr if they are redirected. */
2043 static int setup_redirects(struct command *prog, int squirrel[])
2046 struct redir_struct *redir;
2048 for (redir = prog->redirects; redir; redir = redir->next) {
2049 if (redir->dup == -1 && redir->rd_filename == NULL) {
2050 /* something went wrong in the parse. Pretend it didn't happen */
2053 if (redir->dup == -1) {
2055 mode = redir_table[redir->rd_type].mode;
2056 //TODO: check redir for names like '\\'
2057 p = expand_string_to_string(redir->rd_filename);
2058 openfd = open_or_warn(p, mode);
2061 /* this could get lost if stderr has been redirected, but
2062 bash and ash both lose it as well (though zsh doesn't!) */
2066 openfd = redir->dup;
2069 if (openfd != redir->fd) {
2070 if (squirrel && redir->fd < 3) {
2071 squirrel[redir->fd] = dup(redir->fd);
2074 //close(openfd); // close(-3) ??!
2076 dup2(openfd, redir->fd);
2077 if (redir->dup == -1)
2085 static void restore_redirects(int squirrel[])
2088 for (i = 0; i < 3; i++) {
2091 /* We simply die on error */
2099 #define free_pipe_list(head, indent) free_pipe_list(head)
2100 #define free_pipe(pi, indent) free_pipe(pi)
2102 static void free_pipe_list(struct pipe *head, int indent);
2104 /* Return code is the exit status of the pipe */
2105 static void free_pipe(struct pipe *pi, int indent)
2108 struct command *command;
2109 struct redir_struct *r, *rnext;
2112 if (pi->stopped_cmds > 0) /* why? */
2114 debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
2115 for (i = 0; i < pi->num_cmds; i++) {
2116 command = &pi->cmds[i];
2117 debug_printf_clean("%s command %d:\n", indenter(indent), i);
2118 if (command->argv) {
2119 for (a = 0, p = command->argv; *p; a++, p++) {
2120 debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p);
2122 free_strings(command->argv);
2123 command->argv = NULL;
2125 /* not "else if": on syntax error, we may have both! */
2126 if (command->group) {
2127 debug_printf_clean("%s begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
2128 free_pipe_list(command->group, indent+3);
2129 debug_printf_clean("%s end group\n", indenter(indent));
2130 command->group = NULL;
2133 free(command->group_as_string);
2134 command->group_as_string = NULL;
2136 for (r = command->redirects; r; r = rnext) {
2137 debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->rd_type].descrip);
2139 /* guard against the case >$FOO, where foo is unset or blank */
2140 if (r->rd_filename) {
2141 debug_printf_clean(" %s\n", r->rd_filename);
2142 free(r->rd_filename);
2143 r->rd_filename = NULL;
2146 debug_printf_clean("&%d\n", r->dup);
2151 command->redirects = NULL;
2153 free(pi->cmds); /* children are an array, they get freed all at once */
2161 static void free_pipe_list(struct pipe *head, int indent)
2163 struct pipe *pi, *next;
2165 for (pi = head; pi; pi = next) {
2167 debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word);
2169 free_pipe(pi, indent);
2170 debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup);
2172 /*pi->next = NULL;*/
2179 typedef struct nommu_save_t {
2185 #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
2186 pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
2187 #define pseudo_exec(nommu_save, command, argv_expanded) \
2188 pseudo_exec(command, argv_expanded)
2191 /* Called after [v]fork() in run_pipe(), or from builtin_exec().
2193 * XXX no exit() here. If you don't exec, use _exit instead.
2194 * The at_exit handlers apparently confuse the calling process,
2195 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
2196 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2197 char **argv, int assignment_cnt,
2198 char **argv_expanded) NORETURN;
2199 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2200 char **argv, int assignment_cnt,
2201 char **argv_expanded)
2205 /* Case when we are here: ... | var=val | ... */
2206 if (!argv[assignment_cnt])
2207 _exit(EXIT_SUCCESS);
2209 new_env = expand_assignments(argv, assignment_cnt);
2211 putenv_all(new_env);
2212 free(new_env); /* optional */
2214 nommu_save->new_env = new_env;
2215 nommu_save->old_env = putenv_all_and_save_old(new_env);
2217 if (argv_expanded) {
2218 argv = argv_expanded;
2220 argv = expand_strvec_to_strvec(argv + assignment_cnt);
2222 nommu_save->argv = argv;
2226 /* On NOMMU, we must never block!
2227 * Example: { sleep 99999 | read line } & echo Ok
2228 * read builtin will block on read syscall, leaving parent blocked
2229 * in vfork. Therefore we can't do this:
2232 /* Check if the command matches any of the builtins.
2233 * Depending on context, this might be redundant. But it's
2234 * easier to waste a few CPU cycles than it is to figure out
2235 * if this is one of those cases.
2239 const struct built_in_command *x;
2240 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2241 if (strcmp(argv[0], x->cmd) == 0) {
2242 debug_printf_exec("running builtin '%s'\n",
2244 rcode = x->function(argv);
2252 #if ENABLE_FEATURE_SH_STANDALONE
2253 /* Check if the command matches any busybox applets */
2254 if (strchr(argv[0], '/') == NULL) {
2255 int a = find_applet_by_name(argv[0]);
2257 #if BB_MMU /* see above why on NOMMU it is not allowed */
2258 if (APPLET_IS_NOEXEC(a)) {
2259 debug_printf_exec("running applet '%s'\n", argv[0]);
2260 run_applet_no_and_exit(a, argv);
2263 /* Re-exec ourselves */
2264 debug_printf_exec("re-execing applet '%s'\n", argv[0]);
2265 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2266 execv(bb_busybox_exec_path, argv);
2267 /* If they called chroot or otherwise made the binary no longer
2268 * executable, fall through */
2273 debug_printf_exec("execing '%s'\n", argv[0]);
2274 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2275 execvp(argv[0], argv);
2276 bb_perror_msg("can't exec '%s'", argv[0]);
2277 _exit(EXIT_FAILURE);
2281 static void reset_traps_to_defaults(void)
2289 for (sig = 0; sig < NSIG; sig++) {
2293 G.traps[sig] = NULL;
2294 /* There is no signal for 0 (EXIT) */
2297 /* there was a trap handler, we are removing it
2298 * (if sig has non-DFL handling,
2299 * we don't need to do anything) */
2300 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
2302 sigdelset(&G.blocked_set, sig);
2306 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
2308 #define clean_up_after_re_execute() ((void)0)
2312 static void re_execute_shell(const char *s) NORETURN;
2313 static void re_execute_shell(const char *s)
2315 struct variable *cur;
2316 char **argv, **pp, **pp2;
2319 /* 1:hush 2:-$<pid> 3:-!<pid> 4:-?<exitcode> 5:-D<depth> <vars...>
2320 * 6:-c 7:<cmd> <argN...> 8:NULL
2322 cnt = 8 + G.global_argc;
2323 for (cur = G.top_var; cur; cur = cur->next) {
2324 if (!cur->flg_export || cur->flg_read_only)
2327 G.argv_from_re_execing = pp = xzalloc(sizeof(argv[0]) * cnt);
2328 *pp++ = (char *) G.argv0_for_re_execing;
2329 *pp++ = xasprintf("-$%u", (unsigned) G.root_pid);
2330 *pp++ = xasprintf("-!%u", (unsigned) G.last_bg_pid);
2331 *pp++ = xasprintf("-?%u", (unsigned) G.last_return_code);
2332 #if ENABLE_HUSH_LOOPS
2333 *pp++ = xasprintf("-D%u", G.depth_of_loop);
2335 for (cur = G.top_var; cur; cur = cur->next) {
2336 if (cur->varstr == hush_version_str)
2338 if (cur->flg_read_only) {
2339 *pp++ = (char *) "-R";
2340 *pp++ = cur->varstr;
2341 } else if (!cur->flg_export) {
2342 *pp++ = (char *) "-V";
2343 *pp++ = cur->varstr;
2346 //TODO: pass functions
2347 /* We can pass activated traps here. Say, -Tnn:trap_string
2349 * However, POSIX says that subshells reset signals with traps
2351 * I tested bash-3.2 and it not only does that with true subshells
2352 * of the form ( list ), but with any forked children shells.
2353 * I set trap "echo W" WINCH; and then tried:
2355 * { echo 1; sleep 20; echo 2; } &
2356 * while true; do echo 1; sleep 20; echo 2; break; done &
2357 * true | { echo 1; sleep 20; echo 2; } | cat
2359 * In all these cases sending SIGWINCH to the child shell
2360 * did not run the trap. If I add trap "echo V" WINCH;
2361 * _inside_ group (just before echo 1), it works.
2363 * I conclude it means we don't need to pass active traps here.
2364 * exec syscall below resets them to SIG_DFL for us.
2366 *pp++ = (char *) "-c";
2368 pp2 = G.global_argv;
2371 /* *pp = NULL; - is already there */
2373 debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
2374 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2375 execv(bb_busybox_exec_path, G.argv_from_re_execing);
2376 /* Fallback. Useful for init=/bin/hush usage etc */
2377 if (G.argv0_for_re_execing[0] == '/')
2378 execv(G.argv0_for_re_execing, G.argv_from_re_execing);
2379 xfunc_error_retval = 127;
2380 bb_error_msg_and_die("can't re-execute the shell");
2383 static void clean_up_after_re_execute(void)
2385 char **pp = G.argv_from_re_execing;
2387 /* Must match re_execute_shell's allocations */
2391 #if ENABLE_HUSH_LOOPS
2395 G.argv_from_re_execing = NULL;
2400 static int run_list(struct pipe *pi);
2402 /* Called after [v]fork() in run_pipe()
2404 static void pseudo_exec(nommu_save_t *nommu_save,
2405 struct command *command,
2406 char **argv_expanded) NORETURN;
2407 static void pseudo_exec(nommu_save_t *nommu_save,
2408 struct command *command,
2409 char **argv_expanded)
2411 if (command->argv) {
2412 pseudo_exec_argv(nommu_save, command->argv,
2413 command->assignment_cnt, argv_expanded);
2416 if (command->group) {
2417 /* Cases when we are here:
2420 * ... | ( list ) | ...
2421 * ... | { list } | ...
2425 debug_printf_exec("pseudo_exec: run_list\n");
2426 reset_traps_to_defaults();
2427 rcode = run_list(command->group);
2428 /* OK to leak memory by not calling free_pipe_list,
2429 * since this process is about to exit */
2432 re_execute_shell(command->group_as_string);
2436 /* Case when we are here: ... | >file */
2437 debug_printf_exec("pseudo_exec'ed null command\n");
2438 _exit(EXIT_SUCCESS);
2442 static const char *get_cmdtext(struct pipe *pi)
2448 /* This is subtle. ->cmdtext is created only on first backgrounding.
2449 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
2450 * On subsequent bg argv is trashed, but we won't use it */
2453 argv = pi->cmds[0].argv;
2454 if (!argv || !argv[0]) {
2455 pi->cmdtext = xzalloc(1);
2460 do len += strlen(*argv) + 1; while (*++argv);
2461 pi->cmdtext = p = xmalloc(len);
2462 argv = pi->cmds[0].argv;
2464 len = strlen(*argv);
2465 memcpy(p, *argv, len);
2473 static void insert_bg_job(struct pipe *pi)
2475 struct pipe *thejob;
2478 /* Linear search for the ID of the job to use */
2480 for (thejob = G.job_list; thejob; thejob = thejob->next)
2481 if (thejob->jobid >= pi->jobid)
2482 pi->jobid = thejob->jobid + 1;
2484 /* Add thejob to the list of running jobs */
2486 thejob = G.job_list = xmalloc(sizeof(*thejob));
2488 for (thejob = G.job_list; thejob->next; thejob = thejob->next)
2490 thejob->next = xmalloc(sizeof(*thejob));
2491 thejob = thejob->next;
2494 /* Physically copy the struct job */
2495 memcpy(thejob, pi, sizeof(struct pipe));
2496 thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
2497 /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */
2498 for (i = 0; i < pi->num_cmds; i++) {
2499 // TODO: do we really need to have so many fields which are just dead weight
2500 // at execution stage?
2501 thejob->cmds[i].pid = pi->cmds[i].pid;
2502 /* all other fields are not used and stay zero */
2504 thejob->next = NULL;
2505 thejob->cmdtext = xstrdup(get_cmdtext(pi));
2507 /* We don't wait for background thejobs to return -- append it
2508 to the list of backgrounded thejobs and leave it alone */
2509 if (G_interactive_fd)
2510 printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext);
2511 G.last_bg_pid = thejob->cmds[0].pid;
2512 G.last_jobid = thejob->jobid;
2515 static void remove_bg_job(struct pipe *pi)
2517 struct pipe *prev_pipe;
2519 if (pi == G.job_list) {
2520 G.job_list = pi->next;
2522 prev_pipe = G.job_list;
2523 while (prev_pipe->next != pi)
2524 prev_pipe = prev_pipe->next;
2525 prev_pipe->next = pi->next;
2528 G.last_jobid = G.job_list->jobid;
2533 /* Remove a backgrounded job */
2534 static void delete_finished_bg_job(struct pipe *pi)
2537 pi->stopped_cmds = 0;
2543 /* Check to see if any processes have exited -- if they
2544 * have, figure out why and see if a job has completed */
2545 static int checkjobs(struct pipe* fg_pipe)
2555 debug_printf_jobs("checkjobs %p\n", fg_pipe);
2558 // if (G.handled_SIGCHLD == G.count_SIGCHLD)
2559 // /* avoid doing syscall, nothing there anyway */
2562 attributes = WUNTRACED;
2563 if (fg_pipe == NULL)
2564 attributes |= WNOHANG;
2566 /* Do we do this right?
2567 * bash-3.00# sleep 20 | false
2569 * [3]+ Stopped sleep 20 | false
2570 * bash-3.00# echo $?
2571 * 1 <========== bg pipe is not fully done, but exitcode is already known!
2574 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
2575 //are stopped. Testcase: "cat | cat" in a script (not on command line)
2576 // + killall -STOP cat
2583 // i = G.count_SIGCHLD;
2584 childpid = waitpid(-1, &status, attributes);
2585 if (childpid <= 0) {
2586 if (childpid && errno != ECHILD)
2587 bb_perror_msg("waitpid");
2588 // else /* Until next SIGCHLD, waitpid's are useless */
2589 // G.handled_SIGCHLD = i;
2592 dead = WIFEXITED(status) || WIFSIGNALED(status);
2595 if (WIFSTOPPED(status))
2596 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
2597 childpid, WSTOPSIG(status), WEXITSTATUS(status));
2598 if (WIFSIGNALED(status))
2599 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
2600 childpid, WTERMSIG(status), WEXITSTATUS(status));
2601 if (WIFEXITED(status))
2602 debug_printf_jobs("pid %d exited, exitcode %d\n",
2603 childpid, WEXITSTATUS(status));
2605 /* Were we asked to wait for fg pipe? */
2607 for (i = 0; i < fg_pipe->num_cmds; i++) {
2608 debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
2609 if (fg_pipe->cmds[i].pid != childpid)
2611 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
2613 fg_pipe->cmds[i].pid = 0;
2614 fg_pipe->alive_cmds--;
2615 if (i == fg_pipe->num_cmds - 1) {
2616 /* last process gives overall exitstatus */
2617 rcode = WEXITSTATUS(status);
2618 IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
2621 fg_pipe->cmds[i].is_stopped = 1;
2622 fg_pipe->stopped_cmds++;
2624 debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
2625 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
2626 if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) {
2627 /* All processes in fg pipe have exited/stopped */
2629 if (fg_pipe->alive_cmds)
2630 insert_bg_job(fg_pipe);
2634 /* There are still running processes in the fg pipe */
2635 goto wait_more; /* do waitpid again */
2637 /* it wasnt fg_pipe, look for process in bg pipes */
2641 /* We asked to wait for bg or orphaned children */
2642 /* No need to remember exitcode in this case */
2643 for (pi = G.job_list; pi; pi = pi->next) {
2644 for (i = 0; i < pi->num_cmds; i++) {
2645 if (pi->cmds[i].pid == childpid)
2646 goto found_pi_and_prognum;
2649 /* Happens when shell is used as init process (init=/bin/sh) */
2650 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
2651 continue; /* do waitpid again */
2653 found_pi_and_prognum:
2656 pi->cmds[i].pid = 0;
2658 if (!pi->alive_cmds) {
2659 if (G_interactive_fd)
2660 printf(JOB_STATUS_FORMAT, pi->jobid,
2661 "Done", pi->cmdtext);
2662 delete_finished_bg_job(pi);
2666 pi->cmds[i].is_stopped = 1;
2670 } /* while (waitpid succeeds)... */
2676 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
2679 int rcode = checkjobs(fg_pipe);
2680 /* Job finished, move the shell to the foreground */
2681 p = getpgid(0); /* pgid of our process */
2682 debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
2683 tcsetpgrp(G_interactive_fd, p);
2688 /* Start all the jobs, but don't wait for anything to finish.
2691 * Return code is normally -1, when the caller has to wait for children
2692 * to finish to determine the exit status of the pipe. If the pipe
2693 * is a simple builtin command, however, the action is done by the
2694 * time run_pipe returns, and the exit code is provided as the
2697 * Returns -1 only if started some children. IOW: we have to
2698 * mask out retvals of builtins etc with 0xff!
2700 * The only case when we do not need to [v]fork is when the pipe
2701 * is single, non-backgrounded, non-subshell command. Examples:
2702 * cmd ; ... { list } ; ...
2703 * cmd && ... { list } && ...
2704 * cmd || ... { list } || ...
2705 * If it is, then we can run cmd as a builtin, NOFORK [do we do this?],
2706 * or (if SH_STANDALONE) an applet, and we can run the { list }
2707 * with run_list(). If it isn't one of these, we fork and exec cmd.
2709 * Cases when we must fork:
2710 * non-single: cmd | cmd
2711 * backgrounded: cmd & { list } &
2712 * subshell: ( list ) [&]
2714 static int run_pipe(struct pipe *pi)
2716 static const char *const null_ptr = NULL;
2719 int pipefds[2]; /* pipefds[0] is for reading */
2720 struct command *command;
2721 char **argv_expanded;
2724 /* it is not always needed, but we aim to smaller code */
2725 int squirrel[] = { -1, -1, -1 };
2728 debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
2730 USE_HUSH_JOB(pi->pgrp = -1;)
2731 pi->stopped_cmds = 0;
2732 command = &(pi->cmds[0]);
2733 argv_expanded = NULL;
2735 if (pi->num_cmds != 1
2736 || pi->followup == PIPE_BG
2737 || command->grp_type == GRP_SUBSHELL
2744 debug_printf_exec(": group:%p argv:'%s'\n",
2745 command->group, command->argv ? command->argv[0] : "NONE");
2747 if (command->group) {
2748 #if ENABLE_HUSH_FUNCTIONS
2749 if (command->grp_type == GRP_FUNCTION) {
2750 /* func () { list } */
2751 bb_error_msg("here we ought to remember function definition, and go on");
2752 return EXIT_SUCCESS;
2756 debug_printf("non-subshell group\n");
2757 setup_redirects(command, squirrel);
2758 debug_printf_exec(": run_list\n");
2759 rcode = run_list(command->group) & 0xff;
2760 restore_redirects(squirrel);
2761 debug_printf_exec("run_pipe return %d\n", rcode);
2762 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2766 argv = command->argv ? command->argv : (char **) &null_ptr;
2768 const struct built_in_command *x;
2769 char **new_env = NULL;
2770 char **old_env = NULL;
2772 if (argv[command->assignment_cnt] == NULL) {
2773 /* Assignments, but no command */
2774 /* Ensure redirects take effect. Try "a=t >file" */
2775 setup_redirects(command, squirrel);
2776 restore_redirects(squirrel);
2777 /* Set shell variables */
2779 p = expand_string_to_string(*argv);
2780 debug_printf_exec("set shell var:'%s'->'%s'\n",
2782 set_local_var(p, 0, 0);
2785 /* Do we need to flag set_local_var() errors?
2786 * "assignment to readonly var" and "putenv error"
2788 return EXIT_SUCCESS;
2791 /* Expand the rest into (possibly) many strings each */
2792 argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
2794 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2795 if (strcmp(argv_expanded[0], x->cmd) != 0)
2797 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
2798 debug_printf("exec with redirects only\n");
2799 setup_redirects(command, NULL);
2800 rcode = EXIT_SUCCESS;
2801 goto clean_up_and_ret1;
2803 debug_printf("builtin inline %s\n", argv_expanded[0]);
2804 /* XXX setup_redirects acts on file descriptors, not FILEs.
2805 * This is perfect for work that comes after exec().
2806 * Is it really safe for inline use? Experimentally,
2807 * things seem to work with glibc. */
2808 setup_redirects(command, squirrel);
2809 new_env = expand_assignments(argv, command->assignment_cnt);
2810 old_env = putenv_all_and_save_old(new_env);
2811 debug_printf_exec(": builtin '%s' '%s'...\n",
2812 x->cmd, argv_expanded[1]);
2813 rcode = x->function(argv_expanded) & 0xff;
2814 #if ENABLE_FEATURE_SH_STANDALONE
2817 restore_redirects(squirrel);
2818 free_strings_and_unsetenv(new_env, 1);
2819 putenv_all(old_env);
2820 free(old_env); /* not free_strings()! */
2822 free(argv_expanded);
2823 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2824 debug_printf_exec("run_pipe return %d\n", rcode);
2827 #if ENABLE_FEATURE_SH_STANDALONE
2828 i = find_applet_by_name(argv_expanded[0]);
2829 if (i >= 0 && APPLET_IS_NOFORK(i)) {
2830 setup_redirects(command, squirrel);
2831 save_nofork_data(&G.nofork_save);
2832 new_env = expand_assignments(argv, command->assignment_cnt);
2833 old_env = putenv_all_and_save_old(new_env);
2834 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
2835 argv_expanded[0], argv_expanded[1]);
2836 rcode = run_nofork_applet_prime(&G.nofork_save, i, argv_expanded);
2837 goto clean_up_and_ret;
2840 /* It is neither builtin nor applet. We must fork. */
2844 /* NB: argv_expanded may already be created, and that
2845 * might include `cmd` runs! Do not rerun it! We *must*
2846 * use argv_expanded if it's non-NULL */
2848 /* Going to fork a child per each pipe member */
2852 for (i = 0; i < pi->num_cmds; i++) {
2854 volatile nommu_save_t nommu_save;
2855 nommu_save.new_env = NULL;
2856 nommu_save.old_env = NULL;
2857 nommu_save.argv = NULL;
2859 command = &(pi->cmds[i]);
2860 if (command->argv) {
2861 debug_printf_exec(": pipe member '%s' '%s'...\n",
2862 command->argv[0], command->argv[1]);
2864 debug_printf_exec(": pipe member with no argv\n");
2867 /* pipes are inserted between pairs of commands */
2870 if ((i + 1) < pi->num_cmds)
2873 command->pid = BB_MMU ? fork() : vfork();
2874 if (!command->pid) { /* child */
2876 die_sleep = 0; /* do not restore tty pgrp on xfunc death */
2878 /* Every child adds itself to new process group
2879 * with pgid == pid_of_first_child_in_pipe */
2880 if (G.run_list_level == 1 && G_interactive_fd) {
2883 if (pgrp < 0) /* true for 1st process only */
2885 if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
2886 /* We do it in *every* child, not just first,
2888 tcsetpgrp(G_interactive_fd, pgrp);
2892 xmove_fd(nextin, 0);
2893 xmove_fd(pipefds[1], 1); /* write end */
2895 close(pipefds[0]); /* read end */
2896 /* Like bash, explicit redirects override pipes,
2897 * and the pipe fd is available for dup'ing. */
2898 setup_redirects(command, NULL);
2900 /* Restore default handlers just prior to exec */
2901 /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
2903 /* Stores to nommu_save list of env vars putenv'ed
2904 * (NOMMU, on MMU we don't need that) */
2905 /* cast away volatility... */
2906 pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
2907 /* pseudo_exec() does not return */
2910 /* parent or error */
2912 die_sleep = -1; /* restore tty pgrp on xfunc death */
2915 /* Clean up after vforked child */
2916 clean_up_after_re_execute();
2917 free(nommu_save.argv);
2918 free_strings_and_unsetenv(nommu_save.new_env, 1);
2919 putenv_all(nommu_save.old_env);
2921 free(argv_expanded);
2922 argv_expanded = NULL;
2923 if (command->pid < 0) { /* [v]fork failed */
2924 /* Clearly indicate, was it fork or vfork */
2925 bb_perror_msg(BB_MMU ? "fork" : "vfork");
2929 /* Second and next children need to know pid of first one */
2931 pi->pgrp = command->pid;
2937 if ((i + 1) < pi->num_cmds)
2938 close(pipefds[1]); /* write end */
2939 /* Pass read (output) pipe end to next iteration */
2940 nextin = pipefds[0];
2943 if (!pi->alive_cmds) {
2944 debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
2948 debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
2952 #ifndef debug_print_tree
2953 static void debug_print_tree(struct pipe *pi, int lvl)
2955 static const char *const PIPE[] = {
2961 static const char *RES[] = {
2962 [RES_NONE ] = "NONE" ,
2965 [RES_THEN ] = "THEN" ,
2966 [RES_ELIF ] = "ELIF" ,
2967 [RES_ELSE ] = "ELSE" ,
2970 #if ENABLE_HUSH_LOOPS
2971 [RES_FOR ] = "FOR" ,
2972 [RES_WHILE] = "WHILE",
2973 [RES_UNTIL] = "UNTIL",
2975 [RES_DONE ] = "DONE" ,
2977 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
2980 #if ENABLE_HUSH_CASE
2981 [RES_CASE ] = "CASE" ,
2982 [RES_MATCH] = "MATCH",
2983 [RES_CASEI] = "CASEI",
2984 [RES_ESAC ] = "ESAC" ,
2986 [RES_XXXX ] = "XXXX" ,
2987 [RES_SNTX ] = "SNTX" ,
2989 static const char *const GRPTYPE[] = {
2992 #if ENABLE_HUSH_FUNCTIONS
3001 fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
3002 pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
3004 while (prn < pi->num_cmds) {
3005 struct command *command = &pi->cmds[prn];
3006 char **argv = command->argv;
3008 fprintf(stderr, "%*s prog %d assignment_cnt:%d",
3010 command->assignment_cnt);
3011 if (command->group) {
3012 fprintf(stderr, " group %s: (argv=%p)\n",
3013 GRPTYPE[command->grp_type],
3015 debug_print_tree(command->group, lvl+1);
3019 if (argv) while (*argv) {
3020 fprintf(stderr, " '%s'", *argv);
3023 fprintf(stderr, "\n");
3032 /* NB: called by pseudo_exec, and therefore must not modify any
3033 * global data until exec/_exit (we can be a child after vfork!) */
3034 static int run_list(struct pipe *pi)
3036 #if ENABLE_HUSH_CASE
3037 char *case_word = NULL;
3039 #if ENABLE_HUSH_LOOPS
3040 struct pipe *loop_top = NULL;
3041 char *for_varname = NULL;
3042 char **for_lcur = NULL;
3043 char **for_list = NULL;
3045 smallint flag_skip = 1;
3046 smalluint rcode = 0; /* probably just for compiler */
3047 #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
3048 smalluint cond_code = 0;
3050 enum { cond_code = 0, };
3052 /*enum reserved_style*/ smallint rword = RES_NONE;
3053 /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
3055 debug_printf_exec("run_list start lvl %d\n", G.run_list_level + 1);
3057 #if ENABLE_HUSH_LOOPS
3058 /* Check syntax for "for" */
3059 for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
3060 if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
3062 /* current word is FOR or IN (BOLD in comments below) */
3063 if (cpipe->next == NULL) {
3064 syntax("malformed for");
3065 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3068 /* "FOR v; do ..." and "for v IN a b; do..." are ok */
3069 if (cpipe->next->res_word == RES_DO)
3071 /* next word is not "do". It must be "in" then ("FOR v in ...") */
3072 if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
3073 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
3075 syntax("malformed for");
3076 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3082 /* Past this point, all code paths should jump to ret: label
3083 * in order to return, no direct "return" statements please.
3084 * This helps to ensure that no memory is leaked. */
3086 ////TODO: ctrl-Z handling needs re-thinking and re-testing
3089 /* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
3090 * We are saving state before entering outermost list ("while...done")
3091 * so that ctrl-Z will correctly background _entire_ outermost list,
3092 * not just a part of it (like "sleep 1 | exit 2") */
3093 if (++G.run_list_level == 1 && G_interactive_fd) {
3094 if (sigsetjmp(G.toplevel_jb, 1)) {
3095 /* ctrl-Z forked and we are parent; or ctrl-C.
3096 * Sighandler has longjmped us here */
3097 signal(SIGINT, SIG_IGN);
3098 signal(SIGTSTP, SIG_IGN);
3099 /* Restore level (we can be coming from deep inside
3101 G.run_list_level = 1;
3102 #if ENABLE_FEATURE_SH_STANDALONE
3103 if (G.nofork_save.saved) { /* if save area is valid */
3104 debug_printf_jobs("exiting nofork early\n");
3105 restore_nofork_data(&G.nofork_save);
3108 //// if (G.ctrl_z_flag) {
3109 //// /* ctrl-Z has forked and stored pid of the child in pi->pid.
3110 //// * Remember this child as background job */
3111 //// insert_bg_job(pi);
3113 /* ctrl-C. We just stop doing whatever we were doing */
3116 USE_HUSH_LOOPS(loop_top = NULL;)
3117 USE_HUSH_LOOPS(G.depth_of_loop = 0;)
3121 //// /* ctrl-Z handler will store pid etc in pi */
3122 //// G.toplevel_list = pi;
3123 //// G.ctrl_z_flag = 0;
3124 ////#if ENABLE_FEATURE_SH_STANDALONE
3125 //// G.nofork_save.saved = 0; /* in case we will run a nofork later */
3127 //// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
3128 //// signal(SIGINT, handler_ctrl_c);
3132 /* Go through list of pipes, (maybe) executing them. */
3133 for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
3137 IF_HAS_KEYWORDS(rword = pi->res_word;)
3138 IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
3139 debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
3140 rword, cond_code, skip_more_for_this_rword);
3141 #if ENABLE_HUSH_LOOPS
3142 if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
3143 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
3145 /* start of a loop: remember where loop starts */
3150 if (rword == skip_more_for_this_rword && flag_skip) {
3151 if (pi->followup == PIPE_SEQ)
3153 /* it is "<false> && CMD" or "<true> || CMD"
3154 * and we should not execute CMD */
3158 skip_more_for_this_rword = RES_XXXX;
3161 if (rword == RES_THEN) {
3162 /* "if <false> THEN cmd": skip cmd */
3166 if (rword == RES_ELSE || rword == RES_ELIF) {
3167 /* "if <true> then ... ELSE/ELIF cmd":
3168 * skip cmd and all following ones */
3173 #if ENABLE_HUSH_LOOPS
3174 if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
3176 /* first loop through for */
3178 static const char encoded_dollar_at[] ALIGN1 = {
3179 SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
3180 }; /* encoded representation of "$@" */
3181 static const char *const encoded_dollar_at_argv[] = {
3182 encoded_dollar_at, NULL
3183 }; /* argv list with one element: "$@" */
3186 vals = (char**)encoded_dollar_at_argv;
3187 if (pi->next->res_word == RES_IN) {
3188 /* if no variable values after "in" we skip "for" */
3189 if (!pi->next->cmds[0].argv)
3191 vals = pi->next->cmds[0].argv;
3192 } /* else: "for var; do..." -> assume "$@" list */
3193 /* create list of variable values */
3194 debug_print_strings("for_list made from", vals);
3195 for_list = expand_strvec_to_strvec(vals);
3196 for_lcur = for_list;
3197 debug_print_strings("for_list", for_list);
3198 for_varname = pi->cmds[0].argv[0];
3199 pi->cmds[0].argv[0] = NULL;
3201 free(pi->cmds[0].argv[0]);
3203 /* "for" loop is over, clean up */
3207 pi->cmds[0].argv[0] = for_varname;
3210 /* insert next value from for_lcur */
3211 //TODO: does it need escaping?
3212 pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
3213 pi->cmds[0].assignment_cnt = 1;
3215 if (rword == RES_IN) {
3216 continue; /* "for v IN list;..." - "in" has no cmds anyway */
3218 if (rword == RES_DONE) {
3219 continue; /* "done" has no cmds too */
3222 #if ENABLE_HUSH_CASE
3223 if (rword == RES_CASE) {
3224 case_word = expand_strvec_to_string(pi->cmds->argv);
3227 if (rword == RES_MATCH) {
3230 if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
3232 /* all prev words didn't match, does this one match? */
3233 argv = pi->cmds->argv;
3235 char *pattern = expand_string_to_string(*argv);
3236 /* TODO: which FNM_xxx flags to use? */
3237 cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
3239 if (cond_code == 0) { /* match! we will execute this branch */
3240 free(case_word); /* make future "word)" stop */
3248 if (rword == RES_CASEI) { /* inside of a case branch */
3250 continue; /* not matched yet, skip this pipe */
3253 /* Just pressing <enter> in shell should check for jobs.
3254 * OTOH, in non-interactive shell this is useless
3255 * and only leads to extra job checks */
3256 if (pi->num_cmds == 0) {
3257 if (G_interactive_fd)
3258 goto check_jobs_and_continue;
3262 /* After analyzing all keywords and conditions, we decided
3263 * to execute this pipe. NB: have to do checkjobs(NULL)
3264 * after run_pipe() to collect any background children,
3265 * even if list execution is to be stopped. */
3266 debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
3269 #if ENABLE_HUSH_LOOPS
3270 G.flag_break_continue = 0;
3272 rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
3274 /* we only ran a builtin: rcode is already known
3275 * and we don't need to wait for anything. */
3276 check_and_run_traps(0);
3277 #if ENABLE_HUSH_LOOPS
3278 /* was it "break" or "continue"? */
3279 if (G.flag_break_continue) {
3280 smallint fbc = G.flag_break_continue;
3281 /* we might fall into outer *loop*,
3282 * don't want to break it too */
3284 G.depth_break_continue--;
3285 if (G.depth_break_continue == 0)
3286 G.flag_break_continue = 0;
3287 /* else: e.g. "continue 2" should *break* once, *then* continue */
3288 } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
3289 if (G.depth_break_continue != 0 || fbc == BC_BREAK)
3290 goto check_jobs_and_break;
3291 /* "continue": simulate end of loop */
3296 } else if (pi->followup == PIPE_BG) {
3297 /* what does bash do with attempts to background builtins? */
3298 /* even bash 3.2 doesn't do that well with nested bg:
3299 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
3300 * I'm NOT treating inner &'s as jobs */
3301 check_and_run_traps(0);
3303 if (G.run_list_level == 1)
3306 rcode = 0; /* EXIT_SUCCESS */
3309 if (G.run_list_level == 1 && G_interactive_fd) {
3310 /* waits for completion, then fg's main shell */
3311 rcode = checkjobs_and_fg_shell(pi);
3312 check_and_run_traps(0);
3313 debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
3316 { /* this one just waits for completion */
3317 rcode = checkjobs(pi);
3318 check_and_run_traps(0);
3319 debug_printf_exec(": checkjobs returned %d\n", rcode);
3323 debug_printf_exec(": setting last_return_code=%d\n", rcode);
3324 G.last_return_code = rcode;
3326 /* Analyze how result affects subsequent commands */
3328 if (rword == RES_IF || rword == RES_ELIF)
3331 #if ENABLE_HUSH_LOOPS
3332 if (rword == RES_WHILE) {
3334 rcode = 0; /* "while false; do...done" - exitcode 0 */
3335 goto check_jobs_and_break;
3338 if (rword == RES_UNTIL) {
3340 check_jobs_and_break:
3346 if ((rcode == 0 && pi->followup == PIPE_OR)
3347 || (rcode != 0 && pi->followup == PIPE_AND)
3349 skip_more_for_this_rword = rword;
3352 check_jobs_and_continue:
3357 //// if (G.ctrl_z_flag) {
3358 //// /* ctrl-Z forked somewhere in the past, we are the child,
3359 //// * and now we completed running the list. Exit. */
3365 //// if (!G.run_list_level && G_interactive_fd) {
3366 //// signal(SIGTSTP, SIG_IGN);
3367 //// signal(SIGINT, SIG_IGN);
3370 debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
3371 #if ENABLE_HUSH_LOOPS
3376 #if ENABLE_HUSH_CASE
3382 /* Select which version we will use */
3383 static int run_and_free_list(struct pipe *pi)
3386 debug_printf_exec("run_and_free_list entered\n");
3388 debug_printf_exec(": run_list with %d members\n", pi->num_cmds);
3389 rcode = run_list(pi);
3391 /* free_pipe_list has the side effect of clearing memory.
3392 * In the long run that function can be merged with run_list,
3393 * but doing that now would hobble the debugging effort. */
3394 free_pipe_list(pi, /* indent: */ 0);
3395 debug_printf_exec("run_and_free_list return %d\n", rcode);
3400 /* Peek ahead in the in_str to find out if we have a "&n" construct,
3401 * as in "2>&1", that represents duplicating a file descriptor.
3402 * Return either -2 (syntax error), -1 (no &), or the number found.
3404 static int redirect_dup_num(struct in_str *input)
3406 int ch, d = 0, ok = 0;
3408 if (ch != '&') return -1;
3410 i_getch(input); /* get the & */
3414 return -3; /* "-" represents "close me" */
3416 while (isdigit(ch)) {
3417 d = d*10 + (ch-'0');
3424 bb_error_msg("ambiguous redirect");
3428 /* The src parameter allows us to peek forward to a possible &n syntax
3429 * for file descriptor duplication, e.g., "2>&1".
3430 * Return code is 0 normally, 1 if a syntax error is detected in src.
3431 * Resource errors (in xmalloc) cause the process to exit */
3432 static int setup_redirect(struct parse_context *ctx,
3435 struct in_str *input)
3437 struct command *command = ctx->command;
3438 struct redir_struct *redir;
3439 struct redir_struct **redirp;
3442 /* Check for a '2>&1' type redirect */
3443 dup_num = redirect_dup_num(input);
3445 return 1; /* syntax error */
3447 /* Create a new redir_struct and drop it onto the end of the linked list */
3448 redirp = &command->redirects;
3449 while ((redir = *redirp) != NULL) {
3450 redirp = &(redir->next);
3452 *redirp = redir = xzalloc(sizeof(*redir));
3453 /* redir->next = NULL; */
3454 /* redir->rd_filename = NULL; */
3455 redir->rd_type = style;
3456 redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
3458 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
3460 redir->dup = dup_num;
3461 if (dup_num != -1) {
3462 /* Erik had a check here that the file descriptor in question
3463 * is legit; I postpone that to "run time"
3464 * A "-" representation of "close me" shows up as a -3 here */
3465 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
3467 /* We do _not_ try to open the file that src points to,
3468 * since we need to return and let src be expanded first.
3469 * Set ctx->pending_redirect, so we know what to do at the
3470 * end of the next parsed word. */
3471 ctx->pending_redirect = redir;
3477 static struct pipe *new_pipe(void)
3480 pi = xzalloc(sizeof(struct pipe));
3481 /*pi->followup = 0; - deliberately invalid value */
3482 /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
3486 /* Command (member of a pipe) is complete. The only possible error here
3487 * is out of memory, in which case xmalloc exits. */
3488 static int done_command(struct parse_context *ctx)
3490 /* The command is really already in the pipe structure, so
3491 * advance the pipe counter and make a new, null command. */
3492 struct pipe *pi = ctx->pipe;
3493 struct command *command = ctx->command;
3496 if (command->group == NULL
3497 && command->argv == NULL
3498 && command->redirects == NULL
3500 debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
3501 return pi->num_cmds;
3504 debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
3506 debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
3509 /* Only real trickiness here is that the uncommitted
3510 * command structure is not counted in pi->num_cmds. */
3511 pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
3512 command = &pi->cmds[pi->num_cmds];
3513 memset(command, 0, sizeof(*command));
3515 ctx->command = command;
3516 /* but ctx->pipe and ctx->list_head remain unchanged */
3518 return pi->num_cmds; /* used only for 0/nonzero check */
3521 static void done_pipe(struct parse_context *ctx, pipe_style type)
3525 debug_printf_parse("done_pipe entered, followup %d\n", type);
3526 /* Close previous command */
3527 not_null = done_command(ctx);
3528 ctx->pipe->followup = type;
3529 IF_HAS_KEYWORDS(ctx->pipe->pi_inverted = ctx->ctx_inverted;)
3530 IF_HAS_KEYWORDS(ctx->ctx_inverted = 0;)
3531 IF_HAS_KEYWORDS(ctx->pipe->res_word = ctx->ctx_res_w;)
3533 /* Without this check, even just <enter> on command line generates
3534 * tree of three NOPs (!). Which is harmless but annoying.
3535 * IOW: it is safe to do it unconditionally.
3536 * RES_NONE case is for "for a in; do ..." (empty IN set)
3537 * to work, possibly other cases too. */
3538 if (not_null IF_HAS_KEYWORDS(|| ctx->ctx_res_w != RES_NONE)) {
3540 debug_printf_parse("done_pipe: adding new pipe: "
3541 "not_null:%d ctx->ctx_res_w:%d\n",
3542 not_null, ctx->ctx_res_w);
3544 ctx->pipe->next = new_p;
3546 /* RES_THEN, RES_DO etc are "sticky" -
3547 * they remain set for commands inside if/while.
3548 * This is used to control execution.
3549 * RES_FOR and RES_IN are NOT sticky (needed to support
3550 * cases where variable or value happens to match a keyword):
3552 #if ENABLE_HUSH_LOOPS
3553 if (ctx->ctx_res_w == RES_FOR
3554 || ctx->ctx_res_w == RES_IN)
3555 ctx->ctx_res_w = RES_NONE;
3557 #if ENABLE_HUSH_CASE
3558 if (ctx->ctx_res_w == RES_MATCH)
3559 ctx->ctx_res_w = RES_CASEI;
3561 ctx->command = NULL; /* trick done_command below */
3562 /* Create the memory for command, roughly:
3563 * ctx->pipe->cmds = new struct command;
3564 * ctx->command = &ctx->pipe->cmds[0];
3568 debug_printf_parse("done_pipe return\n");
3571 static void initialize_context(struct parse_context *ctx)
3573 memset(ctx, 0, sizeof(*ctx));
3574 ctx->pipe = ctx->list_head = new_pipe();
3575 /* Create the memory for command, roughly:
3576 * ctx->pipe->cmds = new struct command;
3577 * ctx->command = &ctx->pipe->cmds[0];
3583 /* If a reserved word is found and processed, parse context is modified
3584 * and 1 is returned.
3587 struct reserved_combo {
3590 unsigned char assignment_flag;
3594 FLAG_END = (1 << RES_NONE ),
3596 FLAG_IF = (1 << RES_IF ),
3597 FLAG_THEN = (1 << RES_THEN ),
3598 FLAG_ELIF = (1 << RES_ELIF ),
3599 FLAG_ELSE = (1 << RES_ELSE ),
3600 FLAG_FI = (1 << RES_FI ),
3602 #if ENABLE_HUSH_LOOPS
3603 FLAG_FOR = (1 << RES_FOR ),
3604 FLAG_WHILE = (1 << RES_WHILE),
3605 FLAG_UNTIL = (1 << RES_UNTIL),
3606 FLAG_DO = (1 << RES_DO ),
3607 FLAG_DONE = (1 << RES_DONE ),
3608 FLAG_IN = (1 << RES_IN ),
3610 #if ENABLE_HUSH_CASE
3611 FLAG_MATCH = (1 << RES_MATCH),
3612 FLAG_ESAC = (1 << RES_ESAC ),
3614 FLAG_START = (1 << RES_XXXX ),
3617 static const struct reserved_combo* match_reserved_word(o_string *word)
3619 /* Mostly a list of accepted follow-up reserved words.
3620 * FLAG_END means we are done with the sequence, and are ready
3621 * to turn the compound list into a command.
3622 * FLAG_START means the word must start a new compound list.
3624 static const struct reserved_combo reserved_list[] = {
3626 { "!", RES_NONE, NOT_ASSIGNMENT , 0 },
3627 { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START },
3628 { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
3629 { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN },
3630 { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI },
3631 { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
3633 #if ENABLE_HUSH_LOOPS
3634 { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
3635 { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3636 { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3637 { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
3638 { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE },
3639 { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
3641 #if ENABLE_HUSH_CASE
3642 { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
3643 { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
3646 const struct reserved_combo *r;
3648 for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
3649 if (strcmp(word->data, r->literal) == 0)
3654 static int reserved_word(o_string *word, struct parse_context *ctx)
3656 #if ENABLE_HUSH_CASE
3657 static const struct reserved_combo reserved_match = {
3658 "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
3661 const struct reserved_combo *r;
3663 r = match_reserved_word(word);
3667 debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
3668 #if ENABLE_HUSH_CASE
3669 if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE)
3670 /* "case word IN ..." - IN part starts first match part */
3671 r = &reserved_match;
3674 if (r->flag == 0) { /* '!' */
3675 if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
3676 syntax("! ! command");
3677 IF_HAS_KEYWORDS(ctx->ctx_res_w = RES_SNTX;)
3679 ctx->ctx_inverted = 1;
3682 if (r->flag & FLAG_START) {
3683 struct parse_context *old;
3684 old = xmalloc(sizeof(*old));
3685 debug_printf_parse("push stack %p\n", old);
3686 *old = *ctx; /* physical copy */
3687 initialize_context(ctx);
3689 } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
3691 ctx->ctx_res_w = RES_SNTX;
3694 ctx->ctx_res_w = r->res;
3695 ctx->old_flag = r->flag;
3696 if (ctx->old_flag & FLAG_END) {
3697 struct parse_context *old;
3698 done_pipe(ctx, PIPE_SEQ);
3699 debug_printf_parse("pop stack %p\n", ctx->stack);
3701 old->command->group = ctx->list_head;
3702 old->command->grp_type = GRP_NORMAL;
3704 o_addstr(&old->as_string, ctx->as_string.data);
3705 o_free_unsafe(&ctx->as_string);
3706 old->command->group_as_string = xstrdup(old->as_string.data);
3707 debug_printf_parse("pop, remembering as:'%s'\n",
3708 old->command->group_as_string);
3710 *ctx = *old; /* physical copy */
3713 word->o_assignment = r->assignment_flag;
3718 /* Word is complete, look at it and update parsing context.
3719 * Normal return is 0. Syntax errors return 1.
3720 * Note: on return, word is reset, but not o_free'd!
3722 static int done_word(o_string *word, struct parse_context *ctx)
3724 struct command *command = ctx->command;
3726 debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
3727 if (word->length == 0 && word->nonnull == 0) {
3728 debug_printf_parse("done_word return 0: true null, ignored\n");
3731 /* If this word wasn't an assignment, next ones definitely
3732 * can't be assignments. Even if they look like ones. */
3733 if (word->o_assignment != DEFINITELY_ASSIGNMENT
3734 && word->o_assignment != WORD_IS_KEYWORD
3736 word->o_assignment = NOT_ASSIGNMENT;
3738 if (word->o_assignment == DEFINITELY_ASSIGNMENT)
3739 command->assignment_cnt++;
3740 word->o_assignment = MAYBE_ASSIGNMENT;
3743 if (ctx->pending_redirect) {
3744 /* We do not glob in e.g. >*.tmp case. bash seems to glob here
3745 * only if run as "bash", not "sh" */
3746 ctx->pending_redirect->rd_filename = xstrdup(word->data);
3747 word->o_assignment = NOT_ASSIGNMENT;
3748 debug_printf("word stored in rd_filename: '%s'\n", word->data);
3750 /* "{ echo foo; } echo bar" - bad */
3751 /* NB: bash allows e.g.:
3752 * if true; then { echo foo; } fi
3753 * while if false; then false; fi do break; done
3755 if (command->group) {
3757 debug_printf_parse("done_word return 1: syntax error, "
3758 "groups and arglists don't mix\n");
3762 #if ENABLE_HUSH_CASE
3763 if (ctx->ctx_dsemicolon
3764 && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
3766 /* already done when ctx_dsemicolon was set to 1: */
3767 /* ctx->ctx_res_w = RES_MATCH; */
3768 ctx->ctx_dsemicolon = 0;
3771 if (!command->argv /* if it's the first word... */
3772 #if ENABLE_HUSH_LOOPS
3773 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
3774 && ctx->ctx_res_w != RES_IN
3777 debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
3778 if (reserved_word(word, ctx)) {
3780 debug_printf_parse("done_word return %d\n",
3781 (ctx->ctx_res_w == RES_SNTX));
3782 return (ctx->ctx_res_w == RES_SNTX);
3786 if (word->nonnull /* word had "xx" or 'xx' at least as part of it. */
3787 /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
3788 && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
3789 /* (otherwise it's known to be not empty and is already safe) */
3791 /* exclude "$@" - it can expand to no word despite "" */
3792 char *p = word->data;
3793 while (p[0] == SPECIAL_VAR_SYMBOL
3794 && (p[1] & 0x7f) == '@'
3795 && p[2] == SPECIAL_VAR_SYMBOL
3799 if (p == word->data || p[0] != '\0') {
3800 /* saw no "$@", or not only "$@" but some
3801 * real text is there too */
3802 /* insert "empty variable" reference, this makes
3803 * e.g. "", $empty"" etc to not disappear */
3804 o_addchr(word, SPECIAL_VAR_SYMBOL);
3805 o_addchr(word, SPECIAL_VAR_SYMBOL);
3808 command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
3809 debug_print_strings("word appended to argv", command->argv);
3813 ctx->pending_redirect = NULL;
3815 #if ENABLE_HUSH_LOOPS
3816 /* Force FOR to have just one word (variable name) */
3817 /* NB: basically, this makes hush see "for v in ..." syntax as if
3818 * as it is "for v; in ...". FOR and IN become two pipe structs
3820 if (ctx->ctx_res_w == RES_FOR) {
3821 //TODO: check that command->argv[0] is a valid variable name!
3822 done_pipe(ctx, PIPE_SEQ);
3825 #if ENABLE_HUSH_CASE
3826 /* Force CASE to have just one word */
3827 if (ctx->ctx_res_w == RES_CASE) {
3828 done_pipe(ctx, PIPE_SEQ);
3831 debug_printf_parse("done_word return 0\n");
3835 /* If a redirect is immediately preceded by a number, that number is
3836 * supposed to tell which file descriptor to redirect. This routine
3837 * looks for such preceding numbers. In an ideal world this routine
3838 * needs to handle all the following classes of redirects...
3839 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
3840 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
3841 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
3842 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
3843 * A -1 output from this program means no valid number was found, so the
3844 * caller should use the appropriate default for this redirection.
3846 static int redirect_opt_num(o_string *o)
3852 for (num = 0; num < o->length; num++) {
3853 if (!isdigit(o->data[num])) {
3857 num = atoi(o->data);
3863 #define parse_stream(pstring, input, end_trigger) \
3864 parse_stream(input, end_trigger)
3866 static struct pipe *parse_stream(char **pstring,
3867 struct in_str *input,
3869 static void parse_and_run_string(const char *s);
3871 #if ENABLE_HUSH_TICK
3872 static FILE *generate_stream_from_string(const char *s)
3875 int pid, channel[2];
3878 pid = BB_MMU ? fork() : vfork();
3880 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
3882 if (pid == 0) { /* child */
3884 die_sleep = 0; /* do not restore tty pgrp on xfunc death */
3886 /* Process substitution is not considered to be usual
3887 * 'command execution'.
3888 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
3895 close(channel[0]); /* NB: close _first_, then move fd! */
3896 xmove_fd(channel[1], 1);
3897 /* Prevent it from trying to handle ctrl-z etc */
3898 USE_HUSH_JOB(G.run_list_level = 1;)
3900 reset_traps_to_defaults();
3901 parse_and_run_string(s);
3902 _exit(G.last_return_code);
3904 /* We re-execute after vfork on NOMMU. This makes this script safe:
3905 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >BIG
3906 * huge=`cat BIG` # was blocking here forever
3909 re_execute_shell(s);
3915 die_sleep = -1; /* restore tty pgrp on xfunc death */
3917 clean_up_after_re_execute();
3919 pf = fdopen(channel[0], "r");
3923 /* Return code is exit status of the process that is run. */
3924 static int process_command_subs(o_string *dest, const char *s)
3927 struct in_str pipe_str;
3930 pf = generate_stream_from_string(s);
3933 close_on_exec_on(fileno(pf));
3935 /* Now send results of command back into original context */
3936 setup_file_in_str(&pipe_str, pf);
3938 while ((ch = i_getch(&pipe_str)) != EOF) {
3944 o_addchr(dest, '\n');
3947 o_addQchr(dest, ch);
3950 debug_printf("done reading from pipe, pclose()ing\n");
3951 /* Note: we got EOF, and we just close the read end of the pipe.
3952 * We do not wait for the `cmd` child to terminate. bash and ash do.
3954 * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec
3955 * `false`; echo $? - bash outputs "1"
3958 debug_printf("closed FILE from child. return 0\n");
3963 static int parse_group(o_string *dest, struct parse_context *ctx,
3964 struct in_str *input, int ch)
3966 /* dest contains characters seen prior to ( or {.
3967 * Typically it's empty, but for function defs,
3968 * it contains function name (without '()'). */
3969 struct pipe *pipe_list;
3971 struct command *command = ctx->command;
3973 debug_printf_parse("parse_group entered\n");
3974 #if ENABLE_HUSH_FUNCTIONS
3975 if (ch == 'F') { /* function definition? */
3976 bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
3977 //command->fname = dest->data;
3978 command->grp_type = GRP_FUNCTION;
3979 //TODO: review every o_reset() location... do they handle all o_string fields correctly?
3980 memset(dest, 0, sizeof(*dest));
3983 if (command->argv /* word [word](... */
3984 || dest->length /* word(... */
3985 || dest->nonnull /* ""(... */
3988 debug_printf_parse("parse_group return 1: "
3989 "syntax error, groups and arglists don't mix\n");
3995 command->grp_type = GRP_SUBSHELL;
3999 char *as_string = NULL;
4001 pipe_list = parse_stream(&as_string, input, endch);
4004 o_addstr(&ctx->as_string, as_string);
4006 /* empty ()/{} or parse error? */
4007 if (!pipe_list || pipe_list == ERR_PTR) {
4012 debug_printf_parse("parse_group return 1: "
4013 "parse_stream returned %p\n", pipe_list);
4016 command->group = pipe_list;
4018 as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
4019 command->group_as_string = as_string;
4020 debug_printf_parse("end of group, remembering as:'%s'\n",
4021 command->group_as_string);
4024 debug_printf_parse("parse_group return 0\n");
4026 /* command remains "open", available for possible redirects */
4029 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
4030 /* Subroutines for copying $(...) and `...` things */
4031 static void add_till_backquote(o_string *dest, struct in_str *input);
4033 static void add_till_single_quote(o_string *dest, struct in_str *input)
4036 int ch = i_getch(input);
4044 /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
4045 static void add_till_double_quote(o_string *dest, struct in_str *input)
4048 int ch = i_getch(input);
4051 if (ch == '\\') { /* \x. Copy both chars. */
4053 ch = i_getch(input);
4059 add_till_backquote(dest, input);
4063 //if (ch == '$') ...
4066 /* Process `cmd` - copy contents until "`" is seen. Complicated by
4068 * "Within the backquoted style of command substitution, backslash
4069 * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
4070 * The search for the matching backquote shall be satisfied by the first
4071 * backquote found without a preceding backslash; during this search,
4072 * if a non-escaped backquote is encountered within a shell comment,
4073 * a here-document, an embedded command substitution of the $(command)
4074 * form, or a quoted string, undefined results occur. A single-quoted
4075 * or double-quoted string that begins, but does not end, within the
4076 * "`...`" sequence produces undefined results."
4078 * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
4080 static void add_till_backquote(o_string *dest, struct in_str *input)
4083 int ch = i_getch(input);
4086 if (ch == '\\') { /* \x. Copy both chars unless it is \` */
4087 int ch2 = i_getch(input);
4088 if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
4097 /* Process $(cmd) - copy contents until ")" is seen. Complicated by
4098 * quoting and nested ()s.
4099 * "With the $(command) style of command substitution, all characters
4100 * following the open parenthesis to the matching closing parenthesis
4101 * constitute the command. Any valid shell script can be used for command,
4102 * except a script consisting solely of redirections which produces
4103 * unspecified results."
4105 * echo $(echo '(TEST)' BEST) (TEST) BEST
4106 * echo $(echo 'TEST)' BEST) TEST) BEST
4107 * echo $(echo \(\(TEST\) BEST) ((TEST) BEST
4109 static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
4113 int ch = i_getch(input);
4122 if (i_peek(input) == ')') {
4130 add_till_single_quote(dest, input);
4135 add_till_double_quote(dest, input);
4139 if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */
4140 ch = i_getch(input);
4148 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
4150 /* Return code: 0 for OK, 1 for syntax error */
4152 #define handle_dollar(as_string, dest, input) \
4153 handle_dollar(dest, input)
4155 static int handle_dollar(o_string *as_string,
4157 struct in_str *input)
4160 int ch = i_peek(input); /* first character after the $ */
4161 unsigned char quote_mask = dest->o_escape ? 0x80 : 0;
4163 debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
4165 ch = i_getch(input);
4167 if (as_string) o_addchr(as_string, ch);
4170 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4172 debug_printf_parse(": '%c'\n", ch);
4173 o_addchr(dest, ch | quote_mask);
4176 if (!isalnum(ch) && ch != '_')
4178 ch = i_getch(input);
4180 if (as_string) o_addchr(as_string, ch);
4183 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4184 } else if (isdigit(ch)) {
4186 ch = i_getch(input);
4188 if (as_string) o_addchr(as_string, ch);
4190 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4191 debug_printf_parse(": '%c'\n", ch);
4192 o_addchr(dest, ch | quote_mask);
4193 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4194 } else switch (ch) {
4196 case '!': /* last bg pid */
4197 case '?': /* last exit code */
4198 case '#': /* number of args */
4199 case '*': /* args */
4200 case '@': /* args */
4201 goto make_one_char_var;
4203 bool first_char, all_digits;
4205 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4206 ch = i_getch(input);
4208 if (as_string) o_addchr(as_string, ch);
4210 /* XXX maybe someone will try to escape the '}' */
4215 ch = i_getch(input);
4217 if (as_string) o_addchr(as_string, ch);
4224 /* ${#var}: length of var contents */
4226 else if (isdigit(ch)) {
4233 && ( (all_digits && !isdigit(ch))
4234 || (!all_digits && !isalnum(ch) && ch != '_')
4237 /* handle parameter expansions
4238 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
4243 case ':': /* null modifier */
4244 if (expansion == 0) {
4245 debug_printf_parse(": null modifier\n");
4250 #if 0 /* not implemented yet :( */
4251 case '#': /* remove prefix */
4252 case '%': /* remove suffix */
4253 if (expansion == 0) {
4254 debug_printf_parse(": remove suffix/prefix\n");
4260 case '-': /* default value */
4261 case '=': /* assign default */
4262 case '+': /* alternative */
4263 case '?': /* error indicate */
4264 debug_printf_parse(": parameter expansion\n");
4269 syntax("unterminated ${name}");
4270 debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
4275 debug_printf_parse(": '%c'\n", ch);
4276 o_addchr(dest, ch | quote_mask);
4280 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4283 #if (ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_TICK)
4288 ch = i_getch(input);
4290 if (as_string) o_addchr(as_string, ch);
4292 # if ENABLE_SH_MATH_SUPPORT
4293 if (i_peek(input) == '(') {
4294 ch = i_getch(input);
4296 if (as_string) o_addchr(as_string, ch);
4298 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4299 o_addchr(dest, /*quote_mask |*/ '+');
4303 add_till_closing_paren(dest, input, true);
4306 o_addstr(as_string, dest->data + pos);
4307 o_addchr(as_string, ')');
4308 o_addchr(as_string, ')');
4311 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4315 # if ENABLE_HUSH_TICK
4316 //int pos = dest->length;
4317 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4318 o_addchr(dest, quote_mask | '`');
4322 add_till_closing_paren(dest, input, false);
4325 o_addstr(as_string, dest->data + pos);
4326 o_addchr(as_string, '`');
4329 //debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
4330 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4336 ch = i_getch(input);
4338 if (as_string) o_addchr(as_string, ch);
4341 if (isalnum(ch)) { /* it's $_name or $_123 */
4347 /* $_ Shell or shell script name; or last cmd name */
4348 /* $- Option flags set by set builtin or shell options (-i etc) */
4350 o_addQchr(dest, '$');
4352 debug_printf_parse("handle_dollar return 0\n");
4357 #define parse_stream_dquoted(as_string, dest, input, dquote_end) \
4358 parse_stream_dquoted(dest, input, dquote_end)
4360 static int parse_stream_dquoted(o_string *as_string,
4362 struct in_str *input,
4369 ch = i_getch(input);
4371 if (as_string && ch != EOF)
4372 o_addchr(as_string, ch);
4374 if (ch == dquote_end) { /* may be only '"' or EOF */
4376 if (dest->o_assignment == NOT_ASSIGNMENT)
4377 dest->o_escape ^= 1;
4378 debug_printf_parse("parse_stream_dquoted return 0\n");
4382 syntax("unterminated \"");
4383 debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n");
4388 next = i_peek(input);
4390 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4391 ch, ch, dest->o_escape);
4395 debug_printf_parse("parse_stream_dquoted return 1: \\<eof>\n");
4399 * "The backslash retains its special meaning [in "..."]
4400 * only when followed by one of the following characters:
4401 * $, `, ", \, or <newline>. A double quote may be quoted
4402 * within double quotes by preceding it with a backslash.
4403 * If enabled, history expansion will be performed unless
4404 * an ! appearing in double quotes is escaped using
4405 * a backslash. The backslash preceding the ! is not removed."
4407 if (strchr("$`\"\\", next) != NULL) {
4408 o_addqchr(dest, i_getch(input));
4410 o_addqchr(dest, '\\');
4415 if (handle_dollar(as_string, dest, input) != 0) {
4416 debug_printf_parse("parse_stream_dquoted return 1: "
4417 "handle_dollar returned non-0\n");
4422 #if ENABLE_HUSH_TICK
4424 //int pos = dest->length;
4425 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4426 o_addchr(dest, 0x80 | '`');
4427 add_till_backquote(dest, input);
4428 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4429 //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
4433 o_addQchr(dest, ch);
4435 && (dest->o_assignment == MAYBE_ASSIGNMENT
4436 || dest->o_assignment == WORD_IS_KEYWORD)
4437 && is_assignment(dest->data)
4439 dest->o_assignment = DEFINITELY_ASSIGNMENT;
4445 * Scan input until EOF or end_trigger char.
4446 * Return a list of pipes to execute, or NULL on EOF
4447 * or if end_trigger character is met.
4448 * On syntax error, exit is shell is not interactive,
4449 * reset parsing machinery and start parsing anew,
4450 * or return ERR_PTR.
4452 static struct pipe *parse_stream(char **pstring,
4453 struct in_str *input,
4456 struct parse_context ctx;
4457 o_string dest = NULL_O_STRING;
4460 /* Double-quote state is handled in the state variable is_in_dquote.
4461 * A single-quote triggers a bypass of the main loop until its mate is
4462 * found. When recursing, quote state is passed in via dest->o_escape.
4464 debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
4465 end_trigger ? : 'X');
4467 G.ifs = get_local_var_value("IFS");
4472 #if ENABLE_HUSH_INTERACTIVE
4473 input->promptmode = 0; /* PS1 */
4475 /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */
4476 initialize_context(&ctx);
4480 const char *is_special;
4484 redir_type redir_style;
4487 if (parse_stream_dquoted(&ctx.as_string, &dest, input, '"')) {
4490 /* We reached closing '"' */
4493 ch = i_getch(input);
4494 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4495 ch, ch, dest.o_escape);
4498 if (done_word(&dest, &ctx)) {
4502 done_pipe(&ctx, PIPE_SEQ);
4504 /* If we got nothing... */
4505 // TODO: test script consisting of just "&"
4506 if (pi->num_cmds == 0
4507 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
4509 free_pipe_list(pi, 0);
4512 debug_printf_parse("parse_stream return %p\n", pi);
4514 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4516 *pstring = ctx.as_string.data;
4518 o_free_unsafe(&ctx.as_string);
4523 o_addchr(&ctx.as_string, ch);
4525 is_ifs = strchr(G.ifs, ch);
4526 is_special = strchr("<>;&|(){}#'" /* special outside of "str" */
4527 "\\$\"" USE_HUSH_TICK("`") /* always special */
4530 if (!is_special && !is_ifs) { /* ordinary char */
4531 o_addQchr(&dest, ch);
4532 if ((dest.o_assignment == MAYBE_ASSIGNMENT
4533 || dest.o_assignment == WORD_IS_KEYWORD)
4535 && is_assignment(dest.data)
4537 dest.o_assignment = DEFINITELY_ASSIGNMENT;
4543 if (done_word(&dest, &ctx)) {
4547 #if ENABLE_HUSH_CASE
4548 /* "case ... in <newline> word) ..." -
4549 * newlines are ignored (but ';' wouldn't be) */
4550 if (ctx.command->argv == NULL
4551 && ctx.ctx_res_w == RES_MATCH
4556 /* Treat newline as a command separator. */
4557 done_pipe(&ctx, PIPE_SEQ);
4558 dest.o_assignment = MAYBE_ASSIGNMENT;
4560 /* note: if (is_ifs) continue;
4561 * will still trigger for us */
4564 if (end_trigger && end_trigger == ch) {
4565 //TODO: disallow "{ cmd }" without semicolon
4566 if (done_word(&dest, &ctx)) {
4569 done_pipe(&ctx, PIPE_SEQ);
4570 dest.o_assignment = MAYBE_ASSIGNMENT;
4571 /* Do we sit outside of any if's, loops or case's? */
4573 IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
4575 debug_printf_parse("parse_stream return %p: "
4576 "end_trigger char found\n",
4580 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4582 *pstring = ctx.as_string.data;
4584 o_free_unsafe(&ctx.as_string);
4586 return ctx.list_head;
4592 if (dest.o_assignment == MAYBE_ASSIGNMENT) {
4593 /* ch is a special char and thus this word
4594 * cannot be an assignment */
4595 dest.o_assignment = NOT_ASSIGNMENT;
4600 next = i_peek(input);
4605 if (dest.length == 0) {
4608 if (ch == EOF || ch == '\n')
4611 /* note: we do not add it to &ctx.as_string */
4614 //TODO: go back one char?
4615 o_addchr(&ctx.as_string, '\n');
4618 o_addQchr(&dest, ch);
4626 o_addchr(&dest, '\\');
4627 ch = i_getch(input);
4628 o_addchr(&dest, ch);
4630 o_addchr(&ctx.as_string, ch);
4634 if (handle_dollar(&ctx.as_string, &dest, input) != 0) {
4635 debug_printf_parse("parse_stream parse error: "
4636 "handle_dollar returned non-0\n");
4643 ch = i_getch(input);
4645 syntax("unterminated '");
4649 o_addchr(&ctx.as_string, ch);
4653 if (dest.o_assignment == NOT_ASSIGNMENT)
4654 o_addqchr(&dest, ch);
4656 o_addchr(&dest, ch);
4661 is_in_dquote ^= 1; /* invert */
4662 if (dest.o_assignment == NOT_ASSIGNMENT)
4665 #if ENABLE_HUSH_TICK
4667 //int pos = dest.length;
4668 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4669 o_addchr(&dest, '`');
4670 add_till_backquote(&dest, input);
4671 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4672 //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos);
4677 redir_fd = redirect_opt_num(&dest);
4678 if (done_word(&dest, &ctx)) {
4681 redir_style = REDIRECT_OVERWRITE;
4683 redir_style = REDIRECT_APPEND;
4684 ch = i_getch(input);
4686 o_addchr(&ctx.as_string, ch);
4690 else if (next == '(') {
4691 syntax(">(process) not supported");
4695 setup_redirect(&ctx, redir_fd, redir_style, input);
4698 redir_fd = redirect_opt_num(&dest);
4699 if (done_word(&dest, &ctx)) {
4702 redir_style = REDIRECT_INPUT;
4704 redir_style = REDIRECT_HEREIS;
4705 ch = i_getch(input);
4707 o_addchr(&ctx.as_string, ch);
4709 } else if (next == '>') {
4710 redir_style = REDIRECT_IO;
4711 ch = i_getch(input);
4713 o_addchr(&ctx.as_string, ch);
4717 else if (next == '(') {
4718 syntax("<(process) not supported");
4722 setup_redirect(&ctx, redir_fd, redir_style, input);
4725 #if ENABLE_HUSH_CASE
4728 if (done_word(&dest, &ctx)) {
4731 done_pipe(&ctx, PIPE_SEQ);
4732 #if ENABLE_HUSH_CASE
4733 /* Eat multiple semicolons, detect
4734 * whether it means something special */
4739 ch = i_getch(input);
4741 o_addchr(&ctx.as_string, ch);
4743 if (ctx.ctx_res_w == RES_CASEI) {
4744 ctx.ctx_dsemicolon = 1;
4745 ctx.ctx_res_w = RES_MATCH;
4751 /* We just finished a cmd. New one may start
4752 * with an assignment */
4753 dest.o_assignment = MAYBE_ASSIGNMENT;
4756 if (done_word(&dest, &ctx)) {
4760 ch = i_getch(input);
4762 o_addchr(&ctx.as_string, ch);
4764 done_pipe(&ctx, PIPE_AND);
4766 done_pipe(&ctx, PIPE_BG);
4770 if (done_word(&dest, &ctx)) {
4773 #if ENABLE_HUSH_CASE
4774 if (ctx.ctx_res_w == RES_MATCH)
4775 break; /* we are in case's "word | word)" */
4777 if (next == '|') { /* || */
4778 ch = i_getch(input);
4780 o_addchr(&ctx.as_string, ch);
4782 done_pipe(&ctx, PIPE_OR);
4784 /* we could pick up a file descriptor choice here
4785 * with redirect_opt_num(), but bash doesn't do it.
4786 * "echo foo 2| cat" yields "foo 2". */
4791 #if ENABLE_HUSH_CASE
4792 /* "case... in [(]word)..." - skip '(' */
4793 if (ctx.ctx_res_w == RES_MATCH
4794 && ctx.command->argv == NULL /* not (word|(... */
4795 && dest.length == 0 /* not word(... */
4796 && dest.nonnull == 0 /* not ""(... */
4801 #if ENABLE_HUSH_FUNCTIONS
4802 if (dest.length != 0 /* not just () but word() */
4803 && dest.nonnull == 0 /* not a"b"c() */
4804 && ctx.command->argv == NULL /* it's the first word */
4805 //TODO: "func ( ) {...}" - note spaces - is valid format too in bash
4806 && i_peek(input) == ')'
4807 && !match_reserved_word(&dest)
4809 bb_error_msg("seems like a function definition");
4811 //if !BB_MMU o_addchr(&ctx.as_string...
4813 //TODO: do it properly.
4814 ch = i_getch(input);
4815 } while (ch == ' ' || ch == '\n');
4817 syntax("was expecting {");
4820 ch = 'F'; /* magic value */
4824 if (parse_group(&dest, &ctx, input, ch) != 0) {
4829 #if ENABLE_HUSH_CASE
4830 if (ctx.ctx_res_w == RES_MATCH)
4834 /* proper use of this character is caught by end_trigger:
4835 * if we see {, we call parse_group(..., end_trigger='}')
4836 * and it will match } earlier (not here). */
4837 syntax("unexpected } or )");
4841 bb_error_msg_and_die("BUG: unexpected %c\n", ch);
4847 struct parse_context *pctx;
4848 IF_HAS_KEYWORDS(struct parse_context *p2;)
4850 /* Clean up allocated tree.
4851 * Samples for finding leaks on syntax error recovery path.
4852 * Run them from interactive shell, watch pmap `pidof hush`.
4853 * while if false; then false; fi do break; done
4855 * while if false; then false; fi; do break; fi
4856 * Samples to catch leaks at execution:
4857 * while if (true | {true;}); then echo ok; fi; do break; done
4858 * while if (true | {true;}); then echo ok; fi; do (if echo ok; break; then :; fi) | cat; break; done
4862 /* Update pipe/command counts,
4863 * otherwise freeing may miss some */
4864 done_pipe(pctx, PIPE_SEQ);
4865 debug_printf_clean("freeing list %p from ctx %p\n",
4866 pctx->list_head, pctx);
4867 debug_print_tree(pctx->list_head, 0);
4868 free_pipe_list(pctx->list_head, 0);
4869 debug_printf_clean("freed list %p\n", pctx->list_head);
4871 o_free_unsafe(&pctx->as_string);
4873 IF_HAS_KEYWORDS(p2 = pctx->stack;)
4877 IF_HAS_KEYWORDS(pctx = p2;)
4878 } while (HAS_KEYWORDS && pctx);
4879 /* Free text, clear all dest fields */
4881 /* If we are not in top-level parse, we return,
4882 * our caller will propagate error.
4884 if (end_trigger != ';') {
4891 /* Discard cached input, force prompt */
4893 USE_HUSH_INTERACTIVE(input->promptme = 1;)
4898 /* Executing from string: eval, sh -c '...'
4899 * or from file: /etc/profile, . file, sh <script>, sh (intereactive)
4900 * end_trigger controls how often we stop parsing
4901 * NUL: parse all, execute, return
4902 * ';': parse till ';' or newline, execute, repeat till EOF
4904 static void parse_and_run_stream(struct in_str *inp, int end_trigger)
4907 struct pipe *pipe_list;
4909 pipe_list = parse_stream(NULL, inp, end_trigger);
4910 if (!pipe_list) /* EOF */
4912 debug_print_tree(pipe_list, 0);
4913 debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
4914 run_and_free_list(pipe_list);
4918 static void parse_and_run_string(const char *s)
4920 struct in_str input;
4921 setup_string_in_str(&input, s);
4922 parse_and_run_stream(&input, '\0');
4925 static void parse_and_run_file(FILE *f)
4927 struct in_str input;
4928 setup_file_in_str(&input, f);
4929 parse_and_run_stream(&input, ';');
4932 /* Called a few times only (or even once if "sh -c") */
4933 static void block_signals(int second_time)
4938 mask = (1 << SIGQUIT);
4939 if (G_interactive_fd) {
4945 | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
4950 G.non_DFL_mask = mask;
4953 sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
4957 sigaddset(&G.blocked_set, sig);
4961 sigdelset(&G.blocked_set, SIGCHLD);
4963 sigprocmask(SIG_SETMASK, &G.blocked_set,
4964 second_time ? NULL : &G.inherited_set);
4965 /* POSIX allows shell to re-enable SIGCHLD
4966 * even if it was SIG_IGN on entry */
4967 // G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
4969 signal(SIGCHLD, SIG_DFL); // SIGCHLD_handler);
4974 static void maybe_set_to_sigexit(int sig)
4976 void (*handler)(int);
4977 /* non_DFL_mask'ed signals are, well, masked,
4978 * no need to set handler for them.
4980 if (!((G.non_DFL_mask >> sig) & 1)) {
4981 handler = signal(sig, sigexit);
4982 if (handler == SIG_IGN) /* oops... restore back to IGN! */
4983 signal(sig, handler);
4986 /* Set handlers to restore tty pgrm and exit */
4987 static void set_fatal_handlers(void)
4989 /* We _must_ restore tty pgrp on fatal signals */
4991 maybe_set_to_sigexit(SIGILL );
4992 maybe_set_to_sigexit(SIGFPE );
4993 maybe_set_to_sigexit(SIGBUS );
4994 maybe_set_to_sigexit(SIGSEGV);
4995 maybe_set_to_sigexit(SIGTRAP);
4996 } /* else: hush is perfect. what SEGV? */
4997 maybe_set_to_sigexit(SIGABRT);
4998 /* bash 3.2 seems to handle these just like 'fatal' ones */
4999 maybe_set_to_sigexit(SIGPIPE);
5000 maybe_set_to_sigexit(SIGALRM);
5001 maybe_set_to_sigexit(SIGHUP );
5002 /* if we are interactive, SIGTERM and SIGINT are masked.
5003 * if we aren't interactive... but in this case
5004 * we never want to restore pgrp on exit, and this fn is not called */
5005 /*maybe_set_to_sigexit(SIGTERM);*/
5006 /*maybe_set_to_sigexit(SIGINT );*/
5010 static int set_mode(const char cstate, const char mode)
5012 int state = (cstate == '-' ? 1 : 0);
5014 case 'n': G.fake_mode = state; break;
5015 case 'x': /*G.debug_mode = state;*/ break;
5016 default: return EXIT_FAILURE;
5018 return EXIT_SUCCESS;
5021 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5022 int hush_main(int argc, char **argv)
5024 static const struct variable const_shell_ver = {
5026 .varstr = (char*)hush_version_str,
5027 .max_len = 1, /* 0 can provoke free(name) */
5031 int signal_mask_is_inited = 0;
5034 struct variable *cur_var;
5037 if (EXIT_SUCCESS) /* if EXIT_SUCCESS == 0, is already done */
5038 G.last_return_code = EXIT_SUCCESS;
5040 G.argv0_for_re_execing = argv[0];
5042 /* Deal with HUSH_VERSION */
5043 G.shell_ver = const_shell_ver; /* copying struct here */
5044 G.top_var = &G.shell_ver;
5045 debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
5046 unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
5047 /* Initialize our shell local variables with the values
5048 * currently living in the environment */
5049 cur_var = G.top_var;
5052 char *value = strchr(*e, '=');
5053 if (value) { /* paranoia */
5054 cur_var->next = xzalloc(sizeof(*cur_var));
5055 cur_var = cur_var->next;
5056 cur_var->varstr = *e;
5057 cur_var->max_len = strlen(*e);
5058 cur_var->flg_export = 1;
5062 debug_printf_env("putenv '%s'\n", hush_version_str);
5063 putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
5064 #if ENABLE_FEATURE_EDITING
5065 G.line_input_state = new_line_input_t(FOR_SHELL);
5067 G.global_argc = argc;
5068 G.global_argv = argv;
5069 /* Initialize some more globals to non-zero values */
5071 #if ENABLE_HUSH_INTERACTIVE
5072 if (ENABLE_FEATURE_EDITING)
5073 cmdedit_set_initial_prompt();
5077 /* Shell is non-interactive at first. We need to call
5078 * block_signals(0) if we are going to execute "sh script",
5079 * "sh -c cmds" or login shell's /etc/profile and friends.
5080 * If we later decide that we are interactive, we run block_signals(0)
5081 * (or re-run block_signals(1) if we ran block_signals(0) before)
5082 * in order to intercept (more) signals.
5086 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
5088 opt = getopt(argc, argv, "c:xins"
5098 G.root_pid = getpid();
5099 G.global_argv = argv + optind;
5100 if (!argv[optind]) {
5101 /* -c 'script' (no params): prevent empty $0 */
5102 *--G.global_argv = argv[0];
5104 } /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
5105 G.global_argc = argc - optind;
5106 block_signals(0); /* 0: called 1st time */
5107 parse_and_run_string(optarg);
5110 /* Well, we cannot just declare interactiveness,
5111 * we have to have some stuff (ctty, etc) */
5112 /* G_interactive_fd++; */
5115 /* "-s" means "read from stdin", but this is how we always
5116 * operate, so simply do nothing here. */
5120 G.root_pid = xatoi_u(optarg);
5123 G.last_bg_pid = xatoi_u(optarg);
5126 G.last_return_code = xatoi_u(optarg);
5128 #if ENABLE_HUSH_LOOPS
5130 G.depth_of_loop = xatoi_u(optarg);
5135 set_local_var(xstrdup(optarg), 0, opt == 'R');
5140 if (!set_mode('-', opt))
5144 fprintf(stderr, "Usage: sh [FILE]...\n"
5145 " or: sh -c command [args]...\n\n");
5151 } /* option parsing loop */
5154 G.root_pid = getpid();
5156 /* If we are login shell... */
5157 if (argv[0] && argv[0][0] == '-') {
5159 /* XXX what should argv be while sourcing /etc/profile? */
5160 debug_printf("sourcing /etc/profile\n");
5161 input = fopen_for_read("/etc/profile");
5162 if (input != NULL) {
5163 close_on_exec_on(fileno(input));
5164 block_signals(0); /* 0: called 1st time */
5165 signal_mask_is_inited = 1;
5166 parse_and_run_file(input);
5169 /* bash: after sourcing /etc/profile,
5170 * tries to source (in the given order):
5171 * ~/.bash_profile, ~/.bash_login, ~/.profile,
5172 * stopping of first found. --noprofile turns this off.
5173 * bash also sources ~/.bash_logout on exit.
5174 * If called as sh, skips .bash_XXX files.
5181 * Non-interactive "bash <script>" sources $BASH_ENV here
5182 * (without scanning $PATH).
5183 * If called as sh, does the same but with $ENV.
5185 debug_printf("running script '%s'\n", argv[optind]);
5186 G.global_argv = argv + optind;
5187 G.global_argc = argc - optind;
5188 input = xfopen_for_read(argv[optind]);
5189 close_on_exec_on(fileno(input));
5190 if (!signal_mask_is_inited)
5191 block_signals(0); /* 0: called 1st time */
5192 parse_and_run_file(input);
5193 #if ENABLE_FEATURE_CLEAN_UP
5199 /* Up to here, shell was non-interactive. Now it may become one.
5200 * NB: don't forget to (re)run block_signals(0/1) as needed.
5203 /* A shell is interactive if the '-i' flag was given, or if all of
5204 * the following conditions are met:
5206 * no arguments remaining or the -s flag given
5207 * standard input is a terminal
5208 * standard output is a terminal
5209 * Refer to Posix.2, the description of the 'sh' utility.
5212 if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
5213 G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
5214 debug_printf("saved_tty_pgrp:%d\n", G.saved_tty_pgrp);
5215 if (G.saved_tty_pgrp >= 0) {
5216 /* try to dup stdin to high fd#, >= 255 */
5217 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5218 if (G_interactive_fd < 0) {
5219 /* try to dup to any fd */
5220 G_interactive_fd = dup(STDIN_FILENO);
5221 if (G_interactive_fd < 0)
5223 G_interactive_fd = 0;
5225 // TODO: track & disallow any attempts of user
5226 // to (inadvertently) close/redirect it
5229 debug_printf("interactive_fd:%d\n", G_interactive_fd);
5230 if (G_interactive_fd) {
5233 /* We are indeed interactive shell, and we will perform
5234 * job control. Setting up for that. */
5236 close_on_exec_on(G_interactive_fd);
5237 /* If we were run as 'hush &', sleep until we are
5238 * in the foreground (tty pgrp == our pgrp).
5239 * If we get started under a job aware app (like bash),
5240 * make sure we are now in charge so we don't fight over
5241 * who gets the foreground */
5243 shell_pgrp = getpgrp();
5244 G.saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
5245 if (G.saved_tty_pgrp == shell_pgrp)
5247 /* send TTIN to ourself (should stop us) */
5248 kill(- shell_pgrp, SIGTTIN);
5250 /* Block some signals */
5251 block_signals(signal_mask_is_inited);
5252 /* Set other signals to restore saved_tty_pgrp */
5253 set_fatal_handlers();
5254 /* Put ourselves in our own process group */
5255 bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
5256 /* Grab control of the terminal */
5257 tcsetpgrp(G_interactive_fd, getpid());
5258 /* -1 is special - makes xfuncs longjmp, not exit
5259 * (we reset die_sleep = 0 whereever we [v]fork) */
5261 if (setjmp(die_jmp)) {
5262 /* xfunc has failed! die die die */
5263 hush_exit(xfunc_error_retval);
5265 } else if (!signal_mask_is_inited) {
5266 block_signals(0); /* 0: called 1st time */
5267 } /* else: block_signals(0) was done before */
5268 #elif ENABLE_HUSH_INTERACTIVE
5269 /* No job control compiled in, only prompt/line editing */
5270 if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
5271 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5272 if (G_interactive_fd < 0) {
5273 /* try to dup to any fd */
5274 G_interactive_fd = dup(STDIN_FILENO);
5275 if (G_interactive_fd < 0)
5277 G_interactive_fd = 0;
5280 if (G_interactive_fd) {
5281 close_on_exec_on(G_interactive_fd);
5282 block_signals(signal_mask_is_inited);
5283 } else if (!signal_mask_is_inited) {
5287 /* We have interactiveness code disabled */
5288 if (!signal_mask_is_inited) {
5293 * if interactive but not a login shell, sources ~/.bashrc
5294 * (--norc turns this off, --rcfile <file> overrides)
5297 if (!ENABLE_FEATURE_SH_EXTRA_QUIET && G_interactive_fd) {
5298 printf("\n\n%s hush - the humble shell\n", bb_banner);
5299 printf("Enter 'help' for a list of built-in commands.\n\n");
5302 parse_and_run_file(stdin);
5305 #if ENABLE_FEATURE_CLEAN_UP
5306 if (G.cwd != bb_msg_unknown)
5308 cur_var = G.top_var->next;
5310 struct variable *tmp = cur_var;
5311 if (!cur_var->max_len)
5312 free(cur_var->varstr);
5313 cur_var = cur_var->next;
5317 hush_exit(G.last_return_code);
5322 int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5323 int lash_main(int argc, char **argv)
5325 //bb_error_msg("lash is deprecated, please use hush instead");
5326 return hush_main(argc, argv);
5334 static int builtin_trap(char **argv)
5341 G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
5344 /* No args: print all trapped. This isn't 100% correct as we should
5345 * be escaping the cmd so that it can be pasted back in ...
5347 for (i = 0; i < NSIG; ++i)
5349 printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
5350 return EXIT_SUCCESS;
5355 /* if first arg is decimal: reset all specified */
5356 sig = bb_strtou(*++argv, NULL, 10);
5362 sig = get_signum(*argv++);
5363 if (sig < 0 || sig >= NSIG) {
5365 /* mimic bash message exactly */
5366 bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
5371 G.traps[sig] = xstrdup(new_cmd);
5373 debug_printf("trap: setting SIG%s (%i) to '%s'",
5374 get_signame(sig), sig, G.traps[sig]);
5376 /* There is no signal for 0 (EXIT) */
5381 sigaddset(&G.blocked_set, sig);
5383 /* there was a trap handler, we are removing it
5384 * (if sig has non-DFL handling,
5385 * we don't need to do anything) */
5386 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
5388 sigdelset(&G.blocked_set, sig);
5390 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5395 /* first arg is "-": reset all specified to default */
5396 /* first arg is "": ignore all specified */
5397 /* everything else: execute first arg upon signal */
5399 bb_error_msg("trap: invalid arguments");
5400 return EXIT_FAILURE;
5402 if (LONE_DASH(*argv))
5410 static int builtin_true(char **argv UNUSED_PARAM)
5415 static int builtin_test(char **argv)
5422 return test_main(argc, argv - argc);
5425 static int builtin_echo(char **argv)
5432 return echo_main(argc, argv - argc);
5435 static int builtin_eval(char **argv)
5437 int rcode = EXIT_SUCCESS;
5440 char *str = expand_strvec_to_string(argv + 1);
5442 * eval "echo Hi; done" ("done" is syntax error):
5443 * "echo Hi" will not execute too.
5445 parse_and_run_string(str);
5447 rcode = G.last_return_code;
5452 static int builtin_cd(char **argv)
5455 if (argv[1] == NULL) {
5456 /* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
5457 * bash says "bash: cd: HOME not set" and does nothing (exitcode 1)
5459 newdir = getenv("HOME") ? : "/";
5462 if (chdir(newdir)) {
5463 printf("cd: %s: %s\n", newdir, strerror(errno));
5464 return EXIT_FAILURE;
5467 return EXIT_SUCCESS;
5470 static int builtin_exec(char **argv)
5472 if (argv[1] == NULL)
5473 return EXIT_SUCCESS; /* bash does this */
5478 // FIXME: if exec fails, bash does NOT exit! We do...
5479 pseudo_exec_argv(&dummy, argv + 1, 0, NULL);
5484 static int builtin_exit(char **argv)
5486 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
5487 //puts("exit"); /* bash does it */
5488 // TODO: warn if we have background jobs: "There are stopped jobs"
5489 // On second consecutive 'exit', exit anyway.
5490 if (argv[1] == NULL)
5491 hush_exit(G.last_return_code);
5492 /* mimic bash: exit 123abc == exit 255 + error msg */
5493 xfunc_error_retval = 255;
5494 /* bash: exit -2 == exit 254, no error msg */
5495 hush_exit(xatoi(argv[1]) & 0xff);
5498 static int builtin_export(char **argv)
5501 char *name = argv[1];
5505 // ash emits: export VAR='VAL'
5506 // bash: declare -x VAR="VAL"
5507 // (both also escape as needed (quotes, $, etc))
5512 return EXIT_SUCCESS;
5515 value = strchr(name, '=');
5517 /* They are exporting something without a =VALUE */
5518 struct variable *var;
5520 var = get_local_var(name);
5522 var->flg_export = 1;
5523 debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
5524 putenv(var->varstr);
5526 /* bash does not return an error when trying to export
5527 * an undefined variable. Do likewise. */
5528 return EXIT_SUCCESS;
5531 set_local_var(xstrdup(name), 1, 0);
5532 return EXIT_SUCCESS;
5536 /* built-in 'fg' and 'bg' handler */
5537 static int builtin_fg_bg(char **argv)
5542 if (!G_interactive_fd)
5543 return EXIT_FAILURE;
5544 /* If they gave us no args, assume they want the last backgrounded task */
5546 for (pi = G.job_list; pi; pi = pi->next) {
5547 if (pi->jobid == G.last_jobid) {
5551 bb_error_msg("%s: no current job", argv[0]);
5552 return EXIT_FAILURE;
5554 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
5555 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
5556 return EXIT_FAILURE;
5558 for (pi = G.job_list; pi; pi = pi->next) {
5559 if (pi->jobid == jobnum) {
5563 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
5564 return EXIT_FAILURE;
5566 // TODO: bash prints a string representation
5567 // of job being foregrounded (like "sleep 1 | cat")
5568 if (argv[0][0] == 'f') {
5569 /* Put the job into the foreground. */
5570 tcsetpgrp(G_interactive_fd, pi->pgrp);
5573 /* Restart the processes in the job */
5574 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
5575 for (i = 0; i < pi->num_cmds; i++) {
5576 debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
5577 pi->cmds[i].is_stopped = 0;
5579 pi->stopped_cmds = 0;
5581 i = kill(- pi->pgrp, SIGCONT);
5583 if (errno == ESRCH) {
5584 delete_finished_bg_job(pi);
5585 return EXIT_SUCCESS;
5587 bb_perror_msg("kill (SIGCONT)");
5590 if (argv[0][0] == 'f') {
5592 return checkjobs_and_fg_shell(pi);
5594 return EXIT_SUCCESS;
5598 #if ENABLE_HUSH_HELP
5599 static int builtin_help(char **argv UNUSED_PARAM)
5601 const struct built_in_command *x;
5604 "Built-in commands:\n"
5605 "------------------\n");
5606 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
5607 printf("%s\t%s\n", x->cmd, x->descr);
5610 return EXIT_SUCCESS;
5615 static int builtin_jobs(char **argv UNUSED_PARAM)
5618 const char *status_string;
5620 for (job = G.job_list; job; job = job->next) {
5621 if (job->alive_cmds == job->stopped_cmds)
5622 status_string = "Stopped";
5624 status_string = "Running";
5626 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
5628 return EXIT_SUCCESS;
5632 static int builtin_pwd(char **argv UNUSED_PARAM)
5635 return EXIT_SUCCESS;
5638 static int builtin_read(char **argv)
5641 const char *name = argv[1] ? argv[1] : "REPLY";
5642 //TODO: check that argv[1] is a valid variable name
5644 string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
5645 return set_local_var(string, 0, 0);
5648 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
5649 * built-in 'set' handler
5651 * set [-abCefhmnuvx] [-o option] [argument...]
5652 * set [+abCefhmnuvx] [+o option] [argument...]
5653 * set -- [argument...]
5656 * Implementations shall support the options in both their hyphen and
5657 * plus-sign forms. These options can also be specified as options to sh.
5659 * Write out all variables and their values: set
5660 * Set $1, $2, and $3 and set "$#" to 3: set c a b
5661 * Turn on the -x and -v options: set -xv
5662 * Unset all positional parameters: set --
5663 * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
5664 * Set the positional parameters to the expansion of x, even if x expands
5665 * with a leading '-' or '+': set -- $x
5667 * So far, we only support "set -- [argument...]" and some of the short names.
5669 static int builtin_set(char **argv)
5672 char **pp, **g_argv;
5673 char *arg = *++argv;
5677 for (e = G.top_var; e; e = e->next)
5679 return EXIT_SUCCESS;
5683 if (!strcmp(arg, "--")) {
5688 if (arg[0] == '+' || arg[0] == '-') {
5689 for (n = 1; arg[n]; ++n)
5690 if (set_mode(arg[0], arg[n]))
5696 } while ((arg = *++argv) != NULL);
5697 /* Now argv[0] is 1st argument */
5699 /* Only reset global_argv if we didn't process anything */
5701 return EXIT_SUCCESS;
5704 /* NB: G.global_argv[0] ($0) is never freed/changed */
5705 g_argv = G.global_argv;
5706 if (G.global_args_malloced) {
5712 G.global_args_malloced = 1;
5713 pp = xzalloc(sizeof(pp[0]) * 2);
5714 pp[0] = g_argv[0]; /* retain $0 */
5717 /* This realloc's G.global_argv */
5718 G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
5725 return EXIT_SUCCESS;
5727 /* Nothing known, so abort */
5729 bb_error_msg("set: %s: invalid option", arg);
5730 return EXIT_FAILURE;
5733 static int builtin_shift(char **argv)
5739 if (n >= 0 && n < G.global_argc) {
5740 if (G.global_args_malloced) {
5743 free(G.global_argv[m++]);
5746 memmove(&G.global_argv[1], &G.global_argv[n+1],
5747 G.global_argc * sizeof(G.global_argv[0]));
5748 return EXIT_SUCCESS;
5750 return EXIT_FAILURE;
5753 static int builtin_source(char **argv)
5757 if (argv[1] == NULL)
5758 return EXIT_FAILURE;
5760 /* XXX search through $PATH is missing */
5761 input = fopen_for_read(argv[1]);
5763 bb_error_msg("can't open '%s'", argv[1]);
5764 return EXIT_FAILURE;
5766 close_on_exec_on(fileno(input));
5768 /* Now run the file */
5769 /* XXX argv and argc are broken; need to save old G.global_argv
5770 * (pointer only is OK!) on this stack frame,
5771 * set G.global_argv=argv+1, recurse, and restore. */
5772 parse_and_run_file(input);
5774 return G.last_return_code;
5777 static int builtin_umask(char **argv)
5780 const char *arg = argv[1];
5782 new_umask = bb_strtou(arg, NULL, 8);
5784 return EXIT_FAILURE;
5786 new_umask = umask(0);
5787 printf("%.3o\n", (unsigned) new_umask);
5790 return EXIT_SUCCESS;
5793 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
5794 static int builtin_unset(char **argv)
5801 return EXIT_SUCCESS;
5804 if (argv[1][0] == '-') {
5805 switch (argv[1][1]) {
5807 case 'f': if (ENABLE_HUSH_FUNCTIONS) { var = false; break; }
5809 bb_error_msg("unset: %s: invalid option", argv[1]);
5810 return EXIT_FAILURE;
5818 if (unset_local_var(argv[i]))
5821 #if ENABLE_HUSH_FUNCTIONS
5823 unset_local_func(argv[i]);
5829 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
5830 static int builtin_wait(char **argv)
5832 int ret = EXIT_SUCCESS;
5835 if (*++argv == NULL) {
5836 /* Don't care about wait results */
5837 /* Note 1: must wait until there are no more children */
5838 /* Note 2: must be interruptible */
5840 * $ sleep 3 & sleep 6 & wait
5845 * $ sleep 3 & sleep 6 & wait
5849 * ^C <-- after ~4 sec from keyboard
5852 sigaddset(&G.blocked_set, SIGCHLD);
5853 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5856 if (errno == ECHILD)
5858 /* Wait for SIGCHLD or any other signal of interest */
5859 /* sigtimedwait with infinite timeout: */
5860 sig = sigwaitinfo(&G.blocked_set, NULL);
5862 sig = check_and_run_traps(sig);
5863 if (sig && sig != SIGCHLD) { /* see note 2 */
5869 sigdelset(&G.blocked_set, SIGCHLD);
5870 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5874 /* This is probably buggy wrt interruptible-ness */
5876 pid_t pid = bb_strtou(*argv, NULL, 10);
5878 /* mimic bash message */
5879 bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
5880 return EXIT_FAILURE;
5882 if (waitpid(pid, &status, 0) == pid) {
5883 if (WIFSIGNALED(status))
5884 ret = 128 + WTERMSIG(status);
5885 else if (WIFEXITED(status))
5886 ret = WEXITSTATUS(status);
5890 bb_perror_msg("wait %s", *argv);
5899 #if ENABLE_HUSH_LOOPS
5900 static int builtin_break(char **argv)
5902 if (G.depth_of_loop == 0) {
5903 bb_error_msg("%s: only meaningful in a loop", argv[0]);
5904 return EXIT_SUCCESS; /* bash compat */
5906 G.flag_break_continue++; /* BC_BREAK = 1 */
5907 G.depth_break_continue = 1;
5909 G.depth_break_continue = bb_strtou(argv[1], NULL, 10);
5910 if (errno || !G.depth_break_continue || argv[2]) {
5911 bb_error_msg("%s: bad arguments", argv[0]);
5912 G.flag_break_continue = BC_BREAK;
5913 G.depth_break_continue = UINT_MAX;
5916 if (G.depth_of_loop < G.depth_break_continue)
5917 G.depth_break_continue = G.depth_of_loop;
5918 return EXIT_SUCCESS;
5921 static int builtin_continue(char **argv)
5923 G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
5924 return builtin_break(argv);
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