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 #define HUSH_VER_STR "0.93"
89 #if defined SINGLE_APPLET_MAIN
90 /* STANDALONE does not make sense, and won't compile */
91 #undef CONFIG_FEATURE_SH_STANDALONE
92 #undef ENABLE_FEATURE_SH_STANDALONE
93 #undef USE_FEATURE_SH_STANDALONE
94 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
95 #define ENABLE_FEATURE_SH_STANDALONE 0
96 #define USE_FEATURE_SH_STANDALONE(...)
97 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
100 #if !ENABLE_HUSH_INTERACTIVE
101 #undef ENABLE_FEATURE_EDITING
102 #define ENABLE_FEATURE_EDITING 0
103 #undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
104 #define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
107 /* Do we support ANY keywords? */
108 #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
109 #define HAS_KEYWORDS 1
110 #define IF_HAS_KEYWORDS(...) __VA_ARGS__
111 #define IF_HAS_NO_KEYWORDS(...)
113 #define HAS_KEYWORDS 0
114 #define IF_HAS_KEYWORDS(...)
115 #define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__
118 /* Keep unconditionally on for now */
121 #define ENABLE_HUSH_FUNCTIONS 0
124 /* If you comment out one of these below, it will be #defined later
125 * to perform debug printfs to stderr: */
126 #define debug_printf(...) do {} while (0)
127 /* Finer-grained debug switches */
128 #define debug_printf_parse(...) do {} while (0)
129 #define debug_print_tree(a, b) do {} while (0)
130 #define debug_printf_exec(...) do {} while (0)
131 #define debug_printf_env(...) do {} while (0)
132 #define debug_printf_jobs(...) do {} while (0)
133 #define debug_printf_expand(...) do {} while (0)
134 #define debug_printf_glob(...) do {} while (0)
135 #define debug_printf_list(...) do {} while (0)
136 #define debug_printf_subst(...) do {} while (0)
137 #define debug_printf_clean(...) do {} while (0)
140 #define debug_printf(...) fprintf(stderr, __VA_ARGS__)
143 #ifndef debug_printf_parse
144 #define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__)
147 #ifndef debug_printf_exec
148 #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__)
151 #ifndef debug_printf_env
152 #define debug_printf_env(...) fprintf(stderr, __VA_ARGS__)
155 #ifndef debug_printf_jobs
156 #define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__)
162 #ifndef debug_printf_expand
163 #define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__)
164 #define DEBUG_EXPAND 1
166 #define DEBUG_EXPAND 0
169 #ifndef debug_printf_glob
170 #define debug_printf_glob(...) fprintf(stderr, __VA_ARGS__)
176 #ifndef debug_printf_list
177 #define debug_printf_list(...) fprintf(stderr, __VA_ARGS__)
180 #ifndef debug_printf_subst
181 #define debug_printf_subst(...) fprintf(stderr, __VA_ARGS__)
184 #ifndef debug_printf_clean
185 /* broken, of course, but OK for testing */
186 static const char *indenter(int i)
188 static const char blanks[] ALIGN1 =
190 return &blanks[sizeof(blanks) - i - 1];
192 #define debug_printf_clean(...) fprintf(stderr, __VA_ARGS__)
193 #define DEBUG_CLEAN 1
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="HUSH_VER_STR;
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 **argv_for_re_execing;
492 #if ENABLE_HUSH_LOOPS
493 unsigned depth_break_continue;
494 unsigned depth_of_loop;
498 struct variable *top_var; /* = &G.shell_ver (set in main()) */
499 struct variable shell_ver;
500 /* Signal and trap handling */
501 // unsigned count_SIGCHLD;
502 // unsigned handled_SIGCHLD;
503 /* which signals have non-DFL handler (even with no traps set)? */
504 unsigned non_DFL_mask;
505 char **traps; /* char *traps[NSIG] */
506 sigset_t blocked_set;
507 sigset_t inherited_set;
508 char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
509 #if ENABLE_FEATURE_SH_STANDALONE
510 struct nofork_save_area nofork_save;
513 sigjmp_buf toplevel_jb;
516 #define G (*ptr_to_globals)
517 /* Not #defining name to G.name - this quickly gets unwieldy
518 * (too many defines). Also, I actually prefer to see when a variable
519 * is global, thus "G." prefix is a useful hint */
520 #define INIT_G() do { \
521 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
525 /* Function prototypes for builtins */
526 static int builtin_cd(char **argv);
527 static int builtin_echo(char **argv);
528 static int builtin_eval(char **argv);
529 static int builtin_exec(char **argv);
530 static int builtin_exit(char **argv);
531 static int builtin_export(char **argv);
533 static int builtin_fg_bg(char **argv);
534 static int builtin_jobs(char **argv);
537 static int builtin_help(char **argv);
539 static int builtin_pwd(char **argv);
540 static int builtin_read(char **argv);
541 static int builtin_test(char **argv);
542 static int builtin_trap(char **argv);
543 static int builtin_true(char **argv);
544 static int builtin_set(char **argv);
545 static int builtin_shift(char **argv);
546 static int builtin_source(char **argv);
547 static int builtin_umask(char **argv);
548 static int builtin_unset(char **argv);
549 static int builtin_wait(char **argv);
550 #if ENABLE_HUSH_LOOPS
551 static int builtin_break(char **argv);
552 static int builtin_continue(char **argv);
555 /* Table of built-in functions. They can be forked or not, depending on
556 * context: within pipes, they fork. As simple commands, they do not.
557 * When used in non-forking context, they can change global variables
558 * in the parent shell process. If forked, of course they cannot.
559 * For example, 'unset foo | whatever' will parse and run, but foo will
560 * still be set at the end. */
561 struct built_in_command {
563 int (*function)(char **argv);
566 #define BLTIN(cmd, func, help) { cmd, func, help }
568 #define BLTIN(cmd, func, help) { cmd, func }
572 /* For now, echo and test are unconditionally enabled.
573 * Maybe make it configurable? */
574 static const struct built_in_command bltins[] = {
575 BLTIN("." , builtin_source , "Run commands in a file"),
576 BLTIN(":" , builtin_true , "No-op"),
577 BLTIN("[" , builtin_test , "Test condition"),
579 BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
581 #if ENABLE_HUSH_LOOPS
582 BLTIN("break" , builtin_break , "Exit from a loop"),
584 BLTIN("cd" , builtin_cd , "Change directory"),
585 #if ENABLE_HUSH_LOOPS
586 BLTIN("continue", builtin_continue, "Start new loop iteration"),
588 BLTIN("echo" , builtin_echo , "Write to stdout"),
589 BLTIN("eval" , builtin_eval , "Construct and run shell command"),
590 BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
591 BLTIN("exit" , builtin_exit , "Exit"),
592 BLTIN("export" , builtin_export , "Set environment variable"),
594 BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
597 BLTIN("help" , builtin_help , "List shell built-in commands"),
600 BLTIN("jobs" , builtin_jobs , "List active jobs"),
602 BLTIN("pwd" , builtin_pwd , "Print current directory"),
603 BLTIN("read" , builtin_read , "Input environment variable"),
604 // BLTIN("return" , builtin_return , "Return from a function"),
605 BLTIN("set" , builtin_set , "Set/unset shell local variables"),
606 BLTIN("shift" , builtin_shift , "Shift positional parameters"),
607 BLTIN("test" , builtin_test , "Test condition"),
608 BLTIN("trap" , builtin_trap , "Trap signals"),
609 // BLTIN("ulimit" , builtin_return , "Control resource limits"),
610 BLTIN("umask" , builtin_umask , "Set file creation mask"),
611 BLTIN("unset" , builtin_unset , "Unset environment variable"),
612 BLTIN("wait" , builtin_wait , "Wait for process"),
616 static void maybe_die(const char *notice, const char *msg)
618 /* Was using fancy stuff:
619 * (G_interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...)
620 * but it SEGVs. ?! Oh well... explicit temp ptr works around that */
621 void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die;
622 #if ENABLE_HUSH_INTERACTIVE
623 if (G_interactive_fd)
626 fp(msg ? "%s: %s" : notice, notice, msg);
629 #define syntax(msg) maybe_die("syntax error", msg);
631 /* Debug -- trick gcc to expand __LINE__ and convert to string */
632 #define __syntax(msg, line) maybe_die("syntax error hush.c:" # line, msg)
633 #define _syntax(msg, line) __syntax(msg, line)
634 #define syntax(msg) _syntax(msg, __LINE__)
638 static int glob_needed(const char *s)
643 if (*s == '*' || *s == '[' || *s == '?')
650 static int is_assignment(const char *s)
652 if (!s || !(isalpha(*s) || *s == '_'))
655 while (isalnum(*s) || *s == '_')
660 /* Replace each \x with x in place, return ptr past NUL. */
661 static char *unbackslash(char *src)
667 if ((*dst++ = *src++) == '\0')
673 static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
694 v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
695 v[count1 + count2] = NULL;
698 v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
702 static char **add_string_to_strings(char **strings, char *add)
707 return add_strings_to_strings(strings, v, /*dup:*/ 0);
710 static void putenv_all(char **strings)
715 debug_printf_env("putenv '%s'\n", *strings);
720 static char **putenv_all_and_save_old(char **strings)
730 eq = strchr(*strings, '=');
733 v = getenv(*strings);
736 /* v points to VAL in VAR=VAL, go back to VAR */
737 v -= (eq - *strings) + 1;
738 old = add_string_to_strings(old, v);
747 static void free_strings_and_unsetenv(char **strings, int unset)
757 debug_printf_env("unsetenv '%s'\n", *v);
765 static void free_strings(char **strings)
767 free_strings_and_unsetenv(strings, 0);
771 /* Basic theory of signal handling in shell
772 * ========================================
773 * This does not describe what hush does, rather, it is current understanding
774 * what it _should_ do. If it doesn't, it's a bug.
775 * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
777 * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
778 * is finished or backgrounded. It is the same in interactive and
779 * non-interactive shells, and is the same regardless of whether
780 * a user trap handler is installed or a shell special one is in effect.
781 * ^C or ^Z from keyboard seem to execute "at once" because it usually
782 * backgrounds (i.e. stops) or kills all members of currently running
785 * Wait builtin in interruptible by signals for which user trap is set
786 * or by SIGINT in interactive shell.
788 * Trap handlers will execute even within trap handlers. (right?)
790 * User trap handlers are forgotten when subshell ("(cmd)") is entered. [TODO]
792 * If job control is off, backgrounded commands ("cmd &")
793 * have SIGINT, SIGQUIT set to SIG_IGN.
795 * Commands run in command substitution ("`cmd`")
796 * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
798 * Ordinary commands have signals set to SIG_IGN/DFL set as inherited
799 * by the shell from its parent.
801 * Siganls which differ from SIG_DFL action
802 * (note: child (i.e., [v]forked) shell is not an interactive shell):
805 * SIGTERM (interactive): ignore
806 * SIGHUP (interactive):
807 * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
808 * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
809 * (note that ^Z is handled not by trapping SIGTSTP, but by seeing
810 * that all pipe members are stopped) (right?)
811 * SIGINT (interactive): wait for last pipe, ignore the rest
812 * of the command line, show prompt. NB: ^C does not send SIGINT
813 * to interactive shell while shell is waiting for a pipe,
814 * since shell is bg'ed (is not in foreground process group).
815 * (check/expand this)
816 * Example 1: this waits 5 sec, but does not execute ls:
817 * "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
818 * Example 2: this does not wait and does not execute ls:
819 * "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
820 * Example 3: this does not wait 5 sec, but executes ls:
821 * "sleep 5; ls -l" + press ^C
823 * (What happens to signals which are IGN on shell start?)
824 * (What happens with signal mask on shell start?)
826 * Implementation in hush
827 * ======================
828 * We use in-kernel pending signal mask to determine which signals were sent.
829 * We block all signals which we don't want to take action immediately,
830 * i.e. we block all signals which need to have special handling as described
831 * above, and all signals which have traps set.
832 * After each pipe execution, we extract any pending signals via sigtimedwait()
835 * unsigned non_DFL_mask: a mask of such "special" signals
836 * sigset_t blocked_set: current blocked signal set
839 * clear bit in blocked_set unless it is also in non_DFL_mask
840 * "trap 'cmd' SIGxxx":
841 * set bit in blocked_set (even if 'cmd' is '')
842 * after [v]fork, if we plan to be a shell:
843 * nothing for {} child shell (say, "true | { true; true; } | true")
844 * unset all traps if () shell. [TODO]
845 * after [v]fork, if we plan to exec:
846 * POSIX says pending signal mask is cleared in child - no need to clear it.
847 * Restore blocked signal set to one inherited by shell just prior to exec.
849 * Note: as a result, we do not use signal handlers much. The only uses
850 * are to count SIGCHLDs [disabled - bug somewhere, + bloat]
851 * and to restore tty pgrp on signal-induced exit.
853 * TODO: check/fix wait builtin to be interruptible.
856 //static void SIGCHLD_handler(int sig UNUSED_PARAM)
858 // G.count_SIGCHLD++;
861 /* called once at shell init */
862 static void init_signal_mask(void)
865 unsigned mask = (1 << SIGQUIT);
866 if (G_interactive_fd) {
872 | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
877 G.non_DFL_mask = mask;
879 sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
883 sigaddset(&G.blocked_set, sig);
887 sigdelset(&G.blocked_set, SIGCHLD);
888 sigprocmask(SIG_SETMASK, &G.blocked_set, &G.inherited_set);
891 static int check_and_run_traps(int sig)
893 static const struct timespec zero_timespec = { 0, 0 };
894 smalluint save_rcode;
900 sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec);
905 if (G.traps && G.traps[sig]) {
906 if (G.traps[sig][0]) {
907 /* We have user-defined handler */
908 char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL };
909 save_rcode = G.last_return_code;
912 G.last_return_code = save_rcode;
913 } /* else: "" trap, ignoring signal */
916 /* not a trap: special action */
919 // G.count_SIGCHLD++;
928 default: /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
937 /* Restores tty foreground process group, and exits.
938 * May be called as signal handler for fatal signal
939 * (will faithfully resend signal to itself, producing correct exit state)
940 * or called directly with -EXITCODE.
941 * We also call it if xfunc is exiting. */
942 static void sigexit(int sig) NORETURN;
943 static void sigexit(int sig)
945 /* Disable all signals: job control, SIGPIPE, etc. */
946 sigprocmask_allsigs(SIG_BLOCK);
948 /* Careful: we can end up here after [v]fork. Do not restore
949 * tty pgrp then, only top-level shell process does that */
950 if (G_interactive_fd && getpid() == G.root_pid)
951 tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
953 /* Not a signal, just exit */
957 kill_myself_with_sig(sig); /* does not return */
961 static void maybe_set_sighandler(int sig)
963 void (*handler)(int);
964 /* non_DFL_mask'ed signals are, well, masked,
965 * no need to set handler for them.
967 if (!((G.non_DFL_mask >> sig) & 1)) {
968 handler = signal(sig, sigexit);
969 if (handler == SIG_IGN) /* oops... restore back to IGN! */
970 signal(sig, handler);
973 /* Used only to set handler to restore pgrp on exit */
974 static void set_fatal_signals_to_sigexit(void)
977 maybe_set_sighandler(SIGILL );
978 maybe_set_sighandler(SIGFPE );
979 maybe_set_sighandler(SIGBUS );
980 maybe_set_sighandler(SIGSEGV);
981 maybe_set_sighandler(SIGTRAP);
982 } /* else: hush is perfect. what SEGV? */
984 maybe_set_sighandler(SIGABRT);
986 /* bash 3.2 seems to handle these just like 'fatal' ones */
987 maybe_set_sighandler(SIGPIPE);
988 maybe_set_sighandler(SIGALRM);
989 maybe_set_sighandler(SIGHUP );
991 /* if we aren't interactive... but in this case
992 * we never want to restore pgrp on exit, and this fn is not called */
993 /*maybe_set_sighandler(SIGTERM);*/
994 /*maybe_set_sighandler(SIGINT );*/
999 #define set_fatal_signals_to_sigexit(handler) ((void)0)
1003 /* Restores tty foreground process group, and exits. */
1004 static void hush_exit(int exitcode) NORETURN;
1005 static void hush_exit(int exitcode)
1007 if (G.traps && G.traps[0] && G.traps[0][0]) {
1008 char *argv[] = { NULL, xstrdup(G.traps[0]), NULL };
1014 fflush(NULL); /* flush all streams */
1015 sigexit(- (exitcode & 0xff));
1022 static const char *set_cwd(void)
1024 /* xrealloc_getcwd_or_warn(arg) calls free(arg),
1025 * we must not try to free(bb_msg_unknown) */
1026 if (G.cwd == bb_msg_unknown)
1028 G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
1030 G.cwd = bb_msg_unknown;
1035 /* Get/check local shell variables */
1036 static struct variable *get_local_var(const char *name)
1038 struct variable *cur;
1044 for (cur = G.top_var; cur; cur = cur->next) {
1045 if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
1051 static const char *get_local_var_value(const char *src)
1053 struct variable *var = get_local_var(src);
1055 return strchr(var->varstr, '=') + 1;
1059 /* str holds "NAME=VAL" and is expected to be malloced.
1060 * We take ownership of it.
1064 * -1: if NAME is set, leave export status alone
1065 * if NAME is not set, do not export
1066 * flg_read_only is set only when we handle -R var=val
1069 #define set_local_var(str, flg_export, flg_read_only) \
1070 set_local_var(str, flg_export)
1072 static int set_local_var(char *str, int flg_export, int flg_read_only)
1074 struct variable *cur;
1078 value = strchr(str, '=');
1079 if (!value) { /* not expected to ever happen? */
1084 name_len = value - str + 1; /* including '=' */
1085 cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
1087 if (strncmp(cur->varstr, str, name_len) != 0) {
1089 /* Bail out. Note that now cur points
1090 * to last var in linked list */
1096 /* We found an existing var with this name */
1098 if (cur->flg_read_only) {
1102 bb_error_msg("%s: readonly variable", str);
1106 debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
1107 unsetenv(str); /* just in case */
1109 if (strcmp(cur->varstr, str) == 0) {
1114 if (cur->max_len >= strlen(str)) {
1115 /* This one is from startup env, reuse space */
1116 strcpy(cur->varstr, str);
1119 /* max_len == 0 signifies "malloced" var, which we can
1120 * (and has to) free */
1124 goto set_str_and_exp;
1127 /* Not found - create next variable struct */
1128 cur->next = xzalloc(sizeof(*cur));
1134 cur->flg_read_only = flg_read_only;
1137 if (flg_export == 1)
1138 cur->flg_export = 1;
1139 if (cur->flg_export) {
1140 debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
1141 return putenv(cur->varstr);
1146 static int unset_local_var(const char *name)
1148 struct variable *cur;
1149 struct variable *prev = prev; /* for gcc */
1153 return EXIT_SUCCESS;
1154 name_len = strlen(name);
1157 if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
1158 if (cur->flg_read_only) {
1159 bb_error_msg("%s: readonly variable", name);
1160 return EXIT_FAILURE;
1162 /* prev is ok to use here because 1st variable, HUSH_VERSION,
1163 * is ro, and we cannot reach this code on the 1st pass */
1164 prev->next = cur->next;
1165 debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
1166 bb_unsetenv(cur->varstr);
1170 return EXIT_SUCCESS;
1175 return EXIT_SUCCESS;
1178 #if ENABLE_SH_MATH_SUPPORT
1179 #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c)))
1180 #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c)))
1181 static char *endofname(const char *name)
1189 if (!is_in_name(*p))
1195 static void arith_set_local_var(const char *name, const char *val, int flags)
1197 /* arith code doesnt malloc space, so do it for it */
1198 char *var = xasprintf("%s=%s", name, val);
1199 set_local_var(var, flags, 0);
1207 static int static_get(struct in_str *i)
1216 static int static_peek(struct in_str *i)
1221 #if ENABLE_HUSH_INTERACTIVE
1223 static void cmdedit_set_initial_prompt(void)
1225 if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1226 G.PS1 = getenv("PS1");
1233 static const char* setup_prompt_string(int promptmode)
1235 const char *prompt_str;
1236 debug_printf("setup_prompt_string %d ", promptmode);
1237 if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1238 /* Set up the prompt */
1239 if (promptmode == 0) { /* PS1 */
1241 G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#');
1246 prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
1247 debug_printf("result '%s'\n", prompt_str);
1251 static void get_user_input(struct in_str *i)
1254 const char *prompt_str;
1256 prompt_str = setup_prompt_string(i->promptmode);
1257 #if ENABLE_FEATURE_EDITING
1258 /* Enable command line editing only while a command line
1259 * is actually being read */
1262 /* buglet: SIGINT will not make new prompt to appear _at once_,
1263 * only after <Enter>. (^C will work) */
1264 r = read_line_input(prompt_str, G.user_input_buf, BUFSIZ-1, G.line_input_state);
1265 /* catch *SIGINT* etc (^C is handled by read_line_input) */
1266 check_and_run_traps(0);
1267 } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */
1268 i->eof_flag = (r < 0);
1269 if (i->eof_flag) { /* EOF/error detected */
1270 G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
1271 G.user_input_buf[1] = '\0';
1276 fputs(prompt_str, stdout);
1278 G.user_input_buf[0] = r = fgetc(i->file);
1279 /*G.user_input_buf[1] = '\0'; - already is and never changed */
1280 //do we need check_and_run_traps(0)? (maybe only if stdin)
1281 } while (G.flag_SIGINT);
1282 i->eof_flag = (r == EOF);
1284 i->p = G.user_input_buf;
1287 #endif /* INTERACTIVE */
1289 /* This is the magic location that prints prompts
1290 * and gets data back from the user */
1291 static int file_get(struct in_str *i)
1295 /* If there is data waiting, eat it up */
1296 if (i->p && *i->p) {
1297 #if ENABLE_HUSH_INTERACTIVE
1301 if (i->eof_flag && !*i->p)
1304 /* need to double check i->file because we might be doing something
1305 * more complicated by now, like sourcing or substituting. */
1306 #if ENABLE_HUSH_INTERACTIVE
1307 if (G_interactive_fd && i->promptme && i->file == stdin) {
1310 } while (!*i->p); /* need non-empty line */
1311 i->promptmode = 1; /* PS2 */
1316 ch = fgetc(i->file);
1318 debug_printf("file_get: got a '%c' %d\n", ch, ch);
1319 #if ENABLE_HUSH_INTERACTIVE
1326 /* All the callers guarantee this routine will never be
1327 * used right after a newline, so prompting is not needed.
1329 static int file_peek(struct in_str *i)
1332 if (i->p && *i->p) {
1333 if (i->eof_flag && !i->p[1])
1337 ch = fgetc(i->file);
1338 i->eof_flag = (ch == EOF);
1339 i->peek_buf[0] = ch;
1340 i->peek_buf[1] = '\0';
1342 debug_printf("file_peek: got a '%c' %d\n", *i->p, *i->p);
1346 static void setup_file_in_str(struct in_str *i, FILE *f)
1348 i->peek = file_peek;
1350 #if ENABLE_HUSH_INTERACTIVE
1352 i->promptmode = 0; /* PS1 */
1358 static void setup_string_in_str(struct in_str *i, const char *s)
1360 i->peek = static_peek;
1361 i->get = static_get;
1362 #if ENABLE_HUSH_INTERACTIVE
1364 i->promptmode = 0; /* PS1 */
1374 #define B_CHUNK (32 * sizeof(char*))
1376 static void o_reset(o_string *o)
1384 static void o_free(o_string *o)
1387 memset(o, 0, sizeof(*o));
1390 static ALWAYS_INLINE void o_free_unsafe(o_string *o)
1395 static void o_grow_by(o_string *o, int len)
1397 if (o->length + len > o->maxlen) {
1398 o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
1399 o->data = xrealloc(o->data, 1 + o->maxlen);
1403 static void o_addchr(o_string *o, int ch)
1405 debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
1407 o->data[o->length] = ch;
1409 o->data[o->length] = '\0';
1412 static void o_addblock(o_string *o, const char *str, int len)
1415 memcpy(&o->data[o->length], str, len);
1417 o->data[o->length] = '\0';
1421 static void o_addstr(o_string *o, const char *str)
1423 o_addblock(o, str, strlen(str));
1427 static void o_addstr_with_NUL(o_string *o, const char *str)
1429 o_addblock(o, str, strlen(str) + 1);
1432 static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
1437 && (*str != '*' && *str != '?' && *str != '[')
1445 /* My analysis of quoting semantics tells me that state information
1446 * is associated with a destination, not a source.
1448 static void o_addqchr(o_string *o, int ch)
1451 char *found = strchr("*?[\\", ch);
1456 o->data[o->length] = '\\';
1459 o->data[o->length] = ch;
1461 o->data[o->length] = '\0';
1464 static void o_addQchr(o_string *o, int ch)
1467 if (o->o_escape && strchr("*?[\\", ch)) {
1469 o->data[o->length] = '\\';
1473 o->data[o->length] = ch;
1475 o->data[o->length] = '\0';
1478 static void o_addQstr(o_string *o, const char *str, int len)
1481 o_addblock(o, str, len);
1487 int ordinary_cnt = strcspn(str, "*?[\\");
1488 if (ordinary_cnt > len) /* paranoia */
1490 o_addblock(o, str, ordinary_cnt);
1491 if (ordinary_cnt == len)
1493 str += ordinary_cnt;
1494 len -= ordinary_cnt + 1; /* we are processing + 1 char below */
1498 if (ch) { /* it is necessarily one of "*?[\\" */
1500 o->data[o->length] = '\\';
1504 o->data[o->length] = ch;
1506 o->data[o->length] = '\0';
1510 /* A special kind of o_string for $VAR and `cmd` expansion.
1511 * It contains char* list[] at the beginning, which is grown in 16 element
1512 * increments. Actual string data starts at the next multiple of 16 * (char*).
1513 * list[i] contains an INDEX (int!) into this string data.
1514 * It means that if list[] needs to grow, data needs to be moved higher up
1515 * but list[i]'s need not be modified.
1516 * NB: remembering how many list[i]'s you have there is crucial.
1517 * o_finalize_list() operation post-processes this structure - calculates
1518 * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
1520 #if DEBUG_EXPAND || DEBUG_GLOB
1521 static void debug_print_list(const char *prefix, o_string *o, int n)
1523 char **list = (char**)o->data;
1524 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1526 fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n",
1527 prefix, list, n, string_start, o->length, o->maxlen);
1529 fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i],
1530 o->data + (int)list[i] + string_start,
1531 o->data + (int)list[i] + string_start);
1535 const char *p = o->data + (int)list[n - 1] + string_start;
1536 fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
1540 #define debug_print_list(prefix, o, n) ((void)0)
1543 /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
1544 * in list[n] so that it points past last stored byte so far.
1545 * It returns n+1. */
1546 static int o_save_ptr_helper(o_string *o, int n)
1548 char **list = (char**)o->data;
1552 if (!o->has_empty_slot) {
1553 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1554 string_len = o->length - string_start;
1555 if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
1556 debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
1557 /* list[n] points to string_start, make space for 16 more pointers */
1558 o->maxlen += 0x10 * sizeof(list[0]);
1559 o->data = xrealloc(o->data, o->maxlen + 1);
1560 list = (char**)o->data;
1561 memmove(list + n + 0x10, list + n, string_len);
1562 o->length += 0x10 * sizeof(list[0]);
1564 debug_printf_list("list[%d]=%d string_start=%d\n",
1565 n, string_len, string_start);
1568 /* We have empty slot at list[n], reuse without growth */
1569 string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
1570 string_len = o->length - string_start;
1571 debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n",
1572 n, string_len, string_start);
1573 o->has_empty_slot = 0;
1575 list[n] = (char*)(ptrdiff_t)string_len;
1579 /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
1580 static int o_get_last_ptr(o_string *o, int n)
1582 char **list = (char**)o->data;
1583 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1585 return ((int)(ptrdiff_t)list[n-1]) + string_start;
1588 /* o_glob performs globbing on last list[], saving each result
1589 * as a new list[]. */
1590 static int o_glob(o_string *o, int n)
1596 debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
1598 return o_save_ptr_helper(o, n);
1599 pattern = o->data + o_get_last_ptr(o, n);
1600 debug_printf_glob("glob pattern '%s'\n", pattern);
1601 if (!glob_needed(pattern)) {
1603 o->length = unbackslash(pattern) - o->data;
1604 debug_printf_glob("glob pattern '%s' is literal\n", pattern);
1605 return o_save_ptr_helper(o, n);
1608 memset(&globdata, 0, sizeof(globdata));
1609 gr = glob(pattern, 0, NULL, &globdata);
1610 debug_printf_glob("glob('%s'):%d\n", pattern, gr);
1611 if (gr == GLOB_NOSPACE)
1612 bb_error_msg_and_die("out of memory during glob");
1613 if (gr == GLOB_NOMATCH) {
1614 globfree(&globdata);
1617 if (gr != 0) { /* GLOB_ABORTED ? */
1618 //TODO: testcase for bad glob pattern behavior
1619 bb_error_msg("glob(3) error %d on '%s'", gr, pattern);
1621 if (globdata.gl_pathv && globdata.gl_pathv[0]) {
1622 char **argv = globdata.gl_pathv;
1623 o->length = pattern - o->data; /* "forget" pattern */
1625 o_addstr_with_NUL(o, *argv);
1626 n = o_save_ptr_helper(o, n);
1632 globfree(&globdata);
1634 debug_print_list("o_glob returning", o, n);
1638 /* If o->o_glob == 1, glob the string so far remembered.
1639 * Otherwise, just finish current list[] and start new */
1640 static int o_save_ptr(o_string *o, int n)
1642 if (o->o_glob) { /* if globbing is requested */
1643 /* If o->has_empty_slot, list[n] was already globbed
1644 * (if it was requested back then when it was filled)
1645 * so don't do that again! */
1646 if (!o->has_empty_slot)
1647 return o_glob(o, n); /* o_save_ptr_helper is inside */
1649 return o_save_ptr_helper(o, n);
1652 /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
1653 static char **o_finalize_list(o_string *o, int n)
1658 n = o_save_ptr(o, n); /* force growth for list[n] if necessary */
1660 debug_print_list("finalized", o, n);
1661 debug_printf_expand("finalized n:%d\n", n);
1662 list = (char**)o->data;
1663 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1667 list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start;
1673 /* Expansion can recurse */
1674 #if ENABLE_HUSH_TICK
1675 static int process_command_subs(o_string *dest, const char *s);
1677 static char *expand_string_to_string(const char *str);
1679 #define parse_stream_dquoted(ctx, dest, input, dquote_end) \
1680 parse_stream_dquoted(dest, input, dquote_end)
1682 static int parse_stream_dquoted(struct parse_context *ctx,
1684 struct in_str *input,
1687 /* expand_strvec_to_strvec() takes a list of strings, expands
1688 * all variable references within and returns a pointer to
1689 * a list of expanded strings, possibly with larger number
1690 * of strings. (Think VAR="a b"; echo $VAR).
1691 * This new list is allocated as a single malloc block.
1692 * NULL-terminated list of char* pointers is at the beginning of it,
1693 * followed by strings themself.
1694 * Caller can deallocate entire list by single free(list). */
1696 /* Store given string, finalizing the word and starting new one whenever
1697 * we encounter IFS char(s). This is used for expanding variable values.
1698 * End-of-string does NOT finalize word: think about 'echo -$VAR-' */
1699 static int expand_on_ifs(o_string *output, int n, const char *str)
1702 int word_len = strcspn(str, G.ifs);
1704 if (output->o_escape || !output->o_glob)
1705 o_addQstr(output, str, word_len);
1706 else /* protect backslashes against globbing up :) */
1707 o_addblock_duplicate_backslash(output, str, word_len);
1710 if (!*str) /* EOL - do not finalize word */
1712 o_addchr(output, '\0');
1713 debug_print_list("expand_on_ifs", output, n);
1714 n = o_save_ptr(output, n);
1715 str += strspn(str, G.ifs); /* skip ifs chars */
1717 debug_print_list("expand_on_ifs[1]", output, n);
1721 /* Expand all variable references in given string, adding words to list[]
1722 * at n, n+1,... positions. Return updated n (so that list[n] is next one
1723 * to be filled). This routine is extremely tricky: has to deal with
1724 * variables/parameters with whitespace, $* and $@, and constructs like
1725 * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
1726 static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
1728 /* or_mask is either 0 (normal case) or 0x80
1729 * (expansion of right-hand side of assignment == 1-element expand.
1730 * It will also do no globbing, and thus we must not backslash-quote!) */
1732 char first_ch, ored_ch;
1739 debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
1740 debug_print_list("expand_vars_to_list", output, n);
1741 n = o_save_ptr(output, n);
1742 debug_print_list("expand_vars_to_list[0]", output, n);
1744 while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
1745 #if ENABLE_HUSH_TICK
1746 o_string subst_result = NULL_O_STRING;
1748 #if ENABLE_SH_MATH_SUPPORT
1749 char arith_buf[sizeof(arith_t)*3 + 2];
1751 o_addblock(output, arg, p - arg);
1752 debug_print_list("expand_vars_to_list[1]", output, n);
1754 p = strchr(p, SPECIAL_VAR_SYMBOL);
1756 first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
1757 /* "$@" is special. Even if quoted, it can still
1758 * expand to nothing (not even an empty string) */
1759 if ((first_ch & 0x7f) != '@')
1760 ored_ch |= first_ch;
1763 switch (first_ch & 0x7f) {
1764 /* Highest bit in first_ch indicates that var is double-quoted */
1766 val = utoa(G.root_pid);
1768 case '!': /* bg pid */
1769 val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)"";
1771 case '?': /* exitcode */
1772 val = utoa(G.last_return_code);
1774 case '#': /* argc */
1775 if (arg[1] != SPECIAL_VAR_SYMBOL)
1776 /* actually, it's a ${#var} */
1778 val = utoa(G.global_argc ? G.global_argc-1 : 0);
1783 if (!G.global_argv[i])
1785 ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
1786 if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
1787 smallint sv = output->o_escape;
1788 /* unquoted var's contents should be globbed, so don't escape */
1789 output->o_escape = 0;
1790 while (G.global_argv[i]) {
1791 n = expand_on_ifs(output, n, G.global_argv[i]);
1792 debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
1793 if (G.global_argv[i++][0] && G.global_argv[i]) {
1794 /* this argv[] is not empty and not last:
1795 * put terminating NUL, start new word */
1796 o_addchr(output, '\0');
1797 debug_print_list("expand_vars_to_list[2]", output, n);
1798 n = o_save_ptr(output, n);
1799 debug_print_list("expand_vars_to_list[3]", output, n);
1802 output->o_escape = sv;
1804 /* If or_mask is nonzero, we handle assignment 'a=....$@.....'
1805 * and in this case should treat it like '$*' - see 'else...' below */
1806 if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */
1808 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1809 if (++i >= G.global_argc)
1811 o_addchr(output, '\0');
1812 debug_print_list("expand_vars_to_list[4]", output, n);
1813 n = o_save_ptr(output, n);
1815 } else { /* quoted $*: add as one word */
1817 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1818 if (!G.global_argv[++i])
1821 o_addchr(output, G.ifs[0]);
1825 case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
1826 /* "Empty variable", used to make "" etc to not disappear */
1830 #if ENABLE_HUSH_TICK
1831 case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
1834 //TODO: can we just stuff it into "output" directly?
1835 debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
1836 process_command_subs(&subst_result, arg);
1837 debug_printf_subst("SUBST RES '%s'\n", subst_result.data);
1838 val = subst_result.data;
1841 #if ENABLE_SH_MATH_SUPPORT
1842 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
1843 arith_eval_hooks_t hooks;
1848 arg++; /* skip '+' */
1849 *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
1850 debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
1852 /* Optional: skip expansion if expr is simple ("a + 3", "i++" etc) */
1855 unsigned char c = *exp_str++;
1862 if (strchr(" \t+-*/%_", c) != NULL)
1864 c |= 0x20; /* tolower */
1865 if (c >= 'a' && c <= 'z')
1869 /* We need to expand. Example: "echo $(($a + 1)) $((1 + $((2)) ))" */
1871 struct in_str input;
1872 o_string dest = NULL_O_STRING;
1874 setup_string_in_str(&input, arg);
1875 parse_stream_dquoted(NULL, &dest, &input, EOF);
1876 //bb_error_msg("'%s' -> '%s'", arg, dest.data);
1877 exp_str = expand_string_to_string(dest.data);
1878 //bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
1882 hooks.lookupvar = get_local_var_value;
1883 hooks.setvar = arith_set_local_var;
1884 hooks.endofname = endofname;
1885 res = arith(exp_str ? exp_str : arg, &errcode, &hooks);
1890 case -3: maybe_die("arith", "exponent less than 0"); break;
1891 case -2: maybe_die("arith", "divide by zero"); break;
1892 case -5: maybe_die("arith", "expression recursion loop detected"); break;
1893 default: maybe_die("arith", "syntax error"); break;
1896 debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
1897 sprintf(arith_buf, arith_t_fmt, res);
1902 default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
1904 bool exp_len = false, exp_null = false;
1905 char *var = arg, exp_save, exp_op, *exp_word;
1908 arg[0] = first_ch & 0x7f;
1910 /* prepare for expansions */
1911 if (var[0] == '#') {
1912 /* handle length expansion ${#var} */
1916 /* maybe handle parameter expansion */
1917 exp_off = strcspn(var, ":-=+?");
1921 exp_save = var[exp_off];
1922 exp_null = exp_save == ':';
1923 exp_word = var + exp_off;
1924 if (exp_null) ++exp_word;
1925 exp_op = *exp_word++;
1926 var[exp_off] = '\0';
1930 /* lookup the variable in question */
1931 if (isdigit(var[0])) {
1932 /* handle_dollar() should have vetted var for us */
1934 if (i < G.global_argc)
1935 val = G.global_argv[i];
1936 /* else val remains NULL: $N with too big N */
1938 val = get_local_var_value(var);
1940 /* handle any expansions */
1942 debug_printf_expand("expand: length of '%s' = ", val);
1943 val = utoa(val ? strlen(val) : 0);
1944 debug_printf_expand("%s\n", val);
1945 } else if (exp_off) {
1946 /* we need to do an expansion */
1947 int exp_test = (!val || (exp_null && !val[0]));
1949 exp_test = !exp_test;
1950 debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
1951 exp_null ? "true" : "false", exp_test);
1954 maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
1958 if (exp_op == '=') {
1959 if (isdigit(var[0]) || var[0] == '#') {
1960 maybe_die(var, "special vars cannot assign in this way");
1963 char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
1964 sprintf(new_var, "%s=%s", var, val);
1965 set_local_var(new_var, -1, 0);
1969 var[exp_off] = exp_save;
1973 #if ENABLE_HUSH_TICK
1976 if (!(first_ch & 0x80)) { /* unquoted $VAR */
1977 debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape);
1979 /* unquoted var's contents should be globbed, so don't escape */
1980 smallint sv = output->o_escape;
1981 output->o_escape = 0;
1982 n = expand_on_ifs(output, n, val);
1984 output->o_escape = sv;
1986 } else { /* quoted $VAR, val will be appended below */
1987 debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape);
1990 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
1992 o_addQstr(output, val, strlen(val));
1994 /* Do the check to avoid writing to a const string */
1995 if (*p != SPECIAL_VAR_SYMBOL)
1996 *p = SPECIAL_VAR_SYMBOL;
1998 #if ENABLE_HUSH_TICK
1999 o_free(&subst_result);
2002 } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
2005 debug_print_list("expand_vars_to_list[a]", output, n);
2006 /* this part is literal, and it was already pre-quoted
2007 * if needed (much earlier), do not use o_addQstr here! */
2008 o_addstr_with_NUL(output, arg);
2009 debug_print_list("expand_vars_to_list[b]", output, n);
2010 } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
2011 && !(ored_ch & 0x80) /* and all vars were not quoted. */
2014 /* allow to reuse list[n] later without re-growth */
2015 output->has_empty_slot = 1;
2017 o_addchr(output, '\0');
2022 static char **expand_variables(char **argv, int or_mask)
2027 o_string output = NULL_O_STRING;
2029 if (or_mask & 0x100) {
2030 output.o_escape = 1; /* protect against globbing for "$var" */
2031 /* (unquoted $var will temporarily switch it off) */
2038 n = expand_vars_to_list(&output, n, *v, (char)or_mask);
2041 debug_print_list("expand_variables", &output, n);
2043 /* output.data (malloced in one block) gets returned in "list" */
2044 list = o_finalize_list(&output, n);
2045 debug_print_strings("expand_variables[1]", list);
2049 static char **expand_strvec_to_strvec(char **argv)
2051 return expand_variables(argv, 0x100);
2054 /* Used for expansion of right hand of assignments */
2055 /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs
2057 static char *expand_string_to_string(const char *str)
2059 char *argv[2], **list;
2061 argv[0] = (char*)str;
2063 list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */
2065 if (!list[0] || list[1])
2066 bb_error_msg_and_die("BUG in varexp2");
2067 /* actually, just move string 2*sizeof(char*) bytes back */
2068 overlapping_strcpy((char*)list, list[0]);
2069 debug_printf_expand("string_to_string='%s'\n", (char*)list);
2073 /* Used for "eval" builtin */
2074 static char* expand_strvec_to_string(char **argv)
2078 list = expand_variables(argv, 0x80);
2079 /* Convert all NULs to spaces */
2084 if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
2085 bb_error_msg_and_die("BUG in varexp3");
2086 list[n][-1] = ' '; /* TODO: or to G.ifs[0]? */
2090 overlapping_strcpy((char*)list, list[0]);
2091 debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
2095 static char **expand_assignments(char **argv, int count)
2099 /* Expand assignments into one string each */
2100 for (i = 0; i < count; i++) {
2101 p = add_string_to_strings(p, expand_string_to_string(argv[i]));
2107 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
2108 * and stderr if they are redirected. */
2109 static int setup_redirects(struct command *prog, int squirrel[])
2112 struct redir_struct *redir;
2114 for (redir = prog->redirects; redir; redir = redir->next) {
2115 if (redir->dup == -1 && redir->rd_filename == NULL) {
2116 /* something went wrong in the parse. Pretend it didn't happen */
2119 if (redir->dup == -1) {
2121 mode = redir_table[redir->rd_type].mode;
2122 //TODO: check redir for names like '\\'
2123 p = expand_string_to_string(redir->rd_filename);
2124 openfd = open_or_warn(p, mode);
2127 /* this could get lost if stderr has been redirected, but
2128 bash and ash both lose it as well (though zsh doesn't!) */
2132 openfd = redir->dup;
2135 if (openfd != redir->fd) {
2136 if (squirrel && redir->fd < 3) {
2137 squirrel[redir->fd] = dup(redir->fd);
2140 //close(openfd); // close(-3) ??!
2142 dup2(openfd, redir->fd);
2143 if (redir->dup == -1)
2151 static void restore_redirects(int squirrel[])
2154 for (i = 0; i < 3; i++) {
2157 /* We simply die on error */
2164 #if !defined(DEBUG_CLEAN)
2165 #define free_pipe_list(head, indent) free_pipe_list(head)
2166 #define free_pipe(pi, indent) free_pipe(pi)
2168 static void free_pipe_list(struct pipe *head, int indent);
2170 /* Return code is the exit status of the pipe */
2171 static void free_pipe(struct pipe *pi, int indent)
2174 struct command *command;
2175 struct redir_struct *r, *rnext;
2178 if (pi->stopped_cmds > 0) /* why? */
2180 debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
2181 for (i = 0; i < pi->num_cmds; i++) {
2182 command = &pi->cmds[i];
2183 debug_printf_clean("%s command %d:\n", indenter(indent), i);
2184 if (command->argv) {
2185 for (a = 0, p = command->argv; *p; a++, p++) {
2186 debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p);
2188 free_strings(command->argv);
2189 command->argv = NULL;
2191 /* not "else if": on syntax error, we may have both! */
2192 if (command->group) {
2193 debug_printf_clean("%s begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
2194 free_pipe_list(command->group, indent+3);
2195 debug_printf_clean("%s end group\n", indenter(indent));
2196 command->group = NULL;
2199 free(command->group_as_string);
2200 command->group_as_string = NULL;
2202 for (r = command->redirects; r; r = rnext) {
2203 debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->rd_type].descrip);
2205 /* guard against the case >$FOO, where foo is unset or blank */
2206 if (r->rd_filename) {
2207 debug_printf_clean(" %s\n", r->rd_filename);
2208 free(r->rd_filename);
2209 r->rd_filename = NULL;
2212 debug_printf_clean("&%d\n", r->dup);
2217 command->redirects = NULL;
2219 free(pi->cmds); /* children are an array, they get freed all at once */
2227 static void free_pipe_list(struct pipe *head, int indent)
2229 struct pipe *pi, *next;
2231 for (pi = head; pi; pi = next) {
2233 debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word);
2235 free_pipe(pi, indent);
2236 debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup);
2238 /*pi->next = NULL;*/
2245 typedef struct nommu_save_t {
2251 #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
2252 pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
2253 #define pseudo_exec(nommu_save, command, argv_expanded) \
2254 pseudo_exec(command, argv_expanded)
2257 /* Called after [v]fork() in run_pipe(), or from builtin_exec().
2259 * XXX no exit() here. If you don't exec, use _exit instead.
2260 * The at_exit handlers apparently confuse the calling process,
2261 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
2262 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2263 char **argv, int assignment_cnt,
2264 char **argv_expanded) NORETURN;
2265 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2266 char **argv, int assignment_cnt,
2267 char **argv_expanded)
2271 /* Case when we are here: ... | var=val | ... */
2272 if (!argv[assignment_cnt])
2273 _exit(EXIT_SUCCESS);
2275 new_env = expand_assignments(argv, assignment_cnt);
2277 putenv_all(new_env);
2278 free(new_env); /* optional */
2280 nommu_save->new_env = new_env;
2281 nommu_save->old_env = putenv_all_and_save_old(new_env);
2283 if (argv_expanded) {
2284 argv = argv_expanded;
2286 argv = expand_strvec_to_strvec(argv + assignment_cnt);
2288 nommu_save->argv = argv;
2292 /* On NOMMU, we must never block!
2293 * Example: { sleep 99999 | read line } & echo Ok
2294 * read builtin will block on read syscall, leaving parent blocked
2295 * in vfork. Therefore we can't do this:
2298 /* Check if the command matches any of the builtins.
2299 * Depending on context, this might be redundant. But it's
2300 * easier to waste a few CPU cycles than it is to figure out
2301 * if this is one of those cases.
2305 const struct built_in_command *x;
2306 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2307 if (strcmp(argv[0], x->cmd) == 0) {
2308 debug_printf_exec("running builtin '%s'\n",
2310 rcode = x->function(argv);
2318 #if ENABLE_FEATURE_SH_STANDALONE
2319 /* Check if the command matches any busybox applets */
2320 if (strchr(argv[0], '/') == NULL) {
2321 int a = find_applet_by_name(argv[0]);
2323 #if BB_MMU /* see above why on NOMMU it is not allowed */
2324 if (APPLET_IS_NOEXEC(a)) {
2325 debug_printf_exec("running applet '%s'\n", argv[0]);
2326 run_applet_no_and_exit(a, argv);
2329 /* Re-exec ourselves */
2330 debug_printf_exec("re-execing applet '%s'\n", argv[0]);
2331 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2332 execv(bb_busybox_exec_path, argv);
2333 /* If they called chroot or otherwise made the binary no longer
2334 * executable, fall through */
2339 debug_printf_exec("execing '%s'\n", argv[0]);
2340 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2341 execvp(argv[0], argv);
2342 bb_perror_msg("can't exec '%s'", argv[0]);
2343 _exit(EXIT_FAILURE);
2347 static void re_execute_shell(const char *s) NORETURN;
2348 static void re_execute_shell(const char *s)
2350 struct variable *cur;
2351 char **argv, **pp, **pp2;
2354 /* 1:hush 2:-$<pid> 3:-?<exitcode> 4:-D<depth> <vars...>
2355 * 5:-c 6:<cmd> <argN...> 7:NULL
2357 cnt = 7 + G.global_argc;
2358 for (cur = G.top_var; cur; cur = cur->next) {
2359 if (!cur->flg_export || cur->flg_read_only)
2362 //TODO: need to free these strings in parent!
2363 G.argv_for_re_execing = pp = xmalloc(sizeof(argv[0]) * cnt);
2364 *pp++ = (char *) applet_name;
2365 *pp++ = xasprintf("-$%u", G.root_pid);
2366 *pp++ = xasprintf("-?%u", G.last_return_code);
2367 *pp++ = xasprintf("-D%u", G.depth_of_loop);
2368 for (cur = G.top_var; cur; cur = cur->next) {
2369 if (cur->varstr == hush_version_str)
2371 if (cur->flg_read_only) {
2372 *pp++ = (char *) "-R";
2373 *pp++ = cur->varstr;
2374 } else if (!cur->flg_export) {
2375 *pp++ = (char *) "-V";
2376 *pp++ = cur->varstr;
2379 *pp++ = (char *) "-c";
2381 pp2 = G.global_argv;
2385 //TODO: pass traps and functions
2387 debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
2388 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2389 execv(bb_busybox_exec_path, G.argv_for_re_execing);
2390 //TODO: fallback for init=/bin/hush?
2394 static void clean_up_after_re_execute(void)
2396 char **pp = G.argv_for_re_execing;
2398 /* Must match re_execute_shell's allocations */
2403 G.argv_for_re_execing = NULL;
2407 #define clean_up_after_re_execute() ((void)0)
2410 static int run_list(struct pipe *pi);
2412 /* Called after [v]fork() in run_pipe()
2414 static void pseudo_exec(nommu_save_t *nommu_save,
2415 struct command *command,
2416 char **argv_expanded) NORETURN;
2417 static void pseudo_exec(nommu_save_t *nommu_save,
2418 struct command *command,
2419 char **argv_expanded)
2421 if (command->argv) {
2422 pseudo_exec_argv(nommu_save, command->argv,
2423 command->assignment_cnt, argv_expanded);
2426 if (command->group) {
2427 /* Cases when we are here:
2430 * ... | ( list ) | ...
2431 * ... | { list } | ...
2435 debug_printf_exec("pseudo_exec: run_list\n");
2436 rcode = run_list(command->group);
2437 /* OK to leak memory by not calling free_pipe_list,
2438 * since this process is about to exit */
2441 re_execute_shell(command->group_as_string);
2445 /* Case when we are here: ... | >file */
2446 debug_printf_exec("pseudo_exec'ed null command\n");
2447 _exit(EXIT_SUCCESS);
2451 static const char *get_cmdtext(struct pipe *pi)
2457 /* This is subtle. ->cmdtext is created only on first backgrounding.
2458 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
2459 * On subsequent bg argv is trashed, but we won't use it */
2462 argv = pi->cmds[0].argv;
2463 if (!argv || !argv[0]) {
2464 pi->cmdtext = xzalloc(1);
2469 do len += strlen(*argv) + 1; while (*++argv);
2470 pi->cmdtext = p = xmalloc(len);
2471 argv = pi->cmds[0].argv;
2473 len = strlen(*argv);
2474 memcpy(p, *argv, len);
2482 static void insert_bg_job(struct pipe *pi)
2484 struct pipe *thejob;
2487 /* Linear search for the ID of the job to use */
2489 for (thejob = G.job_list; thejob; thejob = thejob->next)
2490 if (thejob->jobid >= pi->jobid)
2491 pi->jobid = thejob->jobid + 1;
2493 /* Add thejob to the list of running jobs */
2495 thejob = G.job_list = xmalloc(sizeof(*thejob));
2497 for (thejob = G.job_list; thejob->next; thejob = thejob->next)
2499 thejob->next = xmalloc(sizeof(*thejob));
2500 thejob = thejob->next;
2503 /* Physically copy the struct job */
2504 memcpy(thejob, pi, sizeof(struct pipe));
2505 thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
2506 /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */
2507 for (i = 0; i < pi->num_cmds; i++) {
2508 // TODO: do we really need to have so many fields which are just dead weight
2509 // at execution stage?
2510 thejob->cmds[i].pid = pi->cmds[i].pid;
2511 /* all other fields are not used and stay zero */
2513 thejob->next = NULL;
2514 thejob->cmdtext = xstrdup(get_cmdtext(pi));
2516 /* We don't wait for background thejobs to return -- append it
2517 to the list of backgrounded thejobs and leave it alone */
2518 if (G_interactive_fd)
2519 printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext);
2520 G.last_bg_pid = thejob->cmds[0].pid;
2521 G.last_jobid = thejob->jobid;
2524 static void remove_bg_job(struct pipe *pi)
2526 struct pipe *prev_pipe;
2528 if (pi == G.job_list) {
2529 G.job_list = pi->next;
2531 prev_pipe = G.job_list;
2532 while (prev_pipe->next != pi)
2533 prev_pipe = prev_pipe->next;
2534 prev_pipe->next = pi->next;
2537 G.last_jobid = G.job_list->jobid;
2542 /* Remove a backgrounded job */
2543 static void delete_finished_bg_job(struct pipe *pi)
2546 pi->stopped_cmds = 0;
2552 /* Check to see if any processes have exited -- if they
2553 * have, figure out why and see if a job has completed */
2554 static int checkjobs(struct pipe* fg_pipe)
2564 debug_printf_jobs("checkjobs %p\n", fg_pipe);
2567 // if (G.handled_SIGCHLD == G.count_SIGCHLD)
2568 // /* avoid doing syscall, nothing there anyway */
2571 attributes = WUNTRACED;
2572 if (fg_pipe == NULL)
2573 attributes |= WNOHANG;
2575 /* Do we do this right?
2576 * bash-3.00# sleep 20 | false
2578 * [3]+ Stopped sleep 20 | false
2579 * bash-3.00# echo $?
2580 * 1 <========== bg pipe is not fully done, but exitcode is already known!
2583 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
2584 //are stopped. Testcase: "cat | cat" in a script (not on command line)
2585 // + killall -STOP cat
2592 // i = G.count_SIGCHLD;
2593 childpid = waitpid(-1, &status, attributes);
2594 if (childpid <= 0) {
2595 if (childpid && errno != ECHILD)
2596 bb_perror_msg("waitpid");
2597 // else /* Until next SIGCHLD, waitpid's are useless */
2598 // G.handled_SIGCHLD = i;
2601 dead = WIFEXITED(status) || WIFSIGNALED(status);
2604 if (WIFSTOPPED(status))
2605 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
2606 childpid, WSTOPSIG(status), WEXITSTATUS(status));
2607 if (WIFSIGNALED(status))
2608 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
2609 childpid, WTERMSIG(status), WEXITSTATUS(status));
2610 if (WIFEXITED(status))
2611 debug_printf_jobs("pid %d exited, exitcode %d\n",
2612 childpid, WEXITSTATUS(status));
2614 /* Were we asked to wait for fg pipe? */
2616 for (i = 0; i < fg_pipe->num_cmds; i++) {
2617 debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
2618 if (fg_pipe->cmds[i].pid != childpid)
2620 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
2622 fg_pipe->cmds[i].pid = 0;
2623 fg_pipe->alive_cmds--;
2624 if (i == fg_pipe->num_cmds - 1) {
2625 /* last process gives overall exitstatus */
2626 rcode = WEXITSTATUS(status);
2627 IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
2630 fg_pipe->cmds[i].is_stopped = 1;
2631 fg_pipe->stopped_cmds++;
2633 debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
2634 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
2635 if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) {
2636 /* All processes in fg pipe have exited/stopped */
2638 if (fg_pipe->alive_cmds)
2639 insert_bg_job(fg_pipe);
2643 /* There are still running processes in the fg pipe */
2644 goto wait_more; /* do waitpid again */
2646 /* it wasnt fg_pipe, look for process in bg pipes */
2650 /* We asked to wait for bg or orphaned children */
2651 /* No need to remember exitcode in this case */
2652 for (pi = G.job_list; pi; pi = pi->next) {
2653 for (i = 0; i < pi->num_cmds; i++) {
2654 if (pi->cmds[i].pid == childpid)
2655 goto found_pi_and_prognum;
2658 /* Happens when shell is used as init process (init=/bin/sh) */
2659 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
2660 continue; /* do waitpid again */
2662 found_pi_and_prognum:
2665 pi->cmds[i].pid = 0;
2667 if (!pi->alive_cmds) {
2668 if (G_interactive_fd)
2669 printf(JOB_STATUS_FORMAT, pi->jobid,
2670 "Done", pi->cmdtext);
2671 delete_finished_bg_job(pi);
2675 pi->cmds[i].is_stopped = 1;
2679 } /* while (waitpid succeeds)... */
2685 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
2688 int rcode = checkjobs(fg_pipe);
2689 /* Job finished, move the shell to the foreground */
2690 p = getpgid(0); /* pgid of our process */
2691 debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
2692 tcsetpgrp(G_interactive_fd, p);
2697 /* Start all the jobs, but don't wait for anything to finish.
2700 * Return code is normally -1, when the caller has to wait for children
2701 * to finish to determine the exit status of the pipe. If the pipe
2702 * is a simple builtin command, however, the action is done by the
2703 * time run_pipe returns, and the exit code is provided as the
2706 * Returns -1 only if started some children. IOW: we have to
2707 * mask out retvals of builtins etc with 0xff!
2709 * The only case when we do not need to [v]fork is when the pipe
2710 * is single, non-backgrounded, non-subshell command. Examples:
2711 * cmd ; ... { list } ; ...
2712 * cmd && ... { list } && ...
2713 * cmd || ... { list } || ...
2714 * If it is, then we can run cmd as a builtin, NOFORK [do we do this?],
2715 * or (if SH_STANDALONE) an applet, and we can run the { list }
2716 * with run_list(). If it isn't one of these, we fork and exec cmd.
2718 * Cases when we must fork:
2719 * non-single: cmd | cmd
2720 * backgrounded: cmd & { list } &
2721 * subshell: ( list ) [&]
2723 static int run_pipe(struct pipe *pi)
2725 static const char *const null_ptr = NULL;
2728 int pipefds[2]; /* pipefds[0] is for reading */
2729 struct command *command;
2730 char **argv_expanded;
2733 /* it is not always needed, but we aim to smaller code */
2734 int squirrel[] = { -1, -1, -1 };
2737 debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
2739 USE_HUSH_JOB(pi->pgrp = -1;)
2740 pi->stopped_cmds = 0;
2741 command = &(pi->cmds[0]);
2742 argv_expanded = NULL;
2744 if (pi->num_cmds != 1
2745 || pi->followup == PIPE_BG
2746 || command->grp_type == GRP_SUBSHELL
2753 debug_printf_exec(": group:%p argv:'%s'\n",
2754 command->group, command->argv ? command->argv[0] : "NONE");
2756 if (command->group) {
2757 #if ENABLE_HUSH_FUNCTIONS
2758 if (command->grp_type == GRP_FUNCTION) {
2759 /* func () { list } */
2760 bb_error_msg("here we ought to remember function definition, and go on");
2761 return EXIT_SUCCESS;
2765 debug_printf("non-subshell group\n");
2766 setup_redirects(command, squirrel);
2767 debug_printf_exec(": run_list\n");
2768 rcode = run_list(command->group) & 0xff;
2769 restore_redirects(squirrel);
2770 debug_printf_exec("run_pipe return %d\n", rcode);
2771 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2775 argv = command->argv ? command->argv : (char **) &null_ptr;
2777 const struct built_in_command *x;
2778 char **new_env = NULL;
2779 char **old_env = NULL;
2781 if (argv[command->assignment_cnt] == NULL) {
2782 /* Assignments, but no command */
2783 /* Ensure redirects take effect. Try "a=t >file" */
2784 setup_redirects(command, squirrel);
2785 restore_redirects(squirrel);
2786 /* Set shell variables */
2788 p = expand_string_to_string(*argv);
2789 debug_printf_exec("set shell var:'%s'->'%s'\n",
2791 set_local_var(p, 0, 0);
2794 /* Do we need to flag set_local_var() errors?
2795 * "assignment to readonly var" and "putenv error"
2797 return EXIT_SUCCESS;
2800 /* Expand the rest into (possibly) many strings each */
2801 argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
2803 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2804 if (strcmp(argv_expanded[0], x->cmd) != 0)
2806 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
2807 debug_printf("exec with redirects only\n");
2808 setup_redirects(command, NULL);
2809 rcode = EXIT_SUCCESS;
2810 goto clean_up_and_ret1;
2812 debug_printf("builtin inline %s\n", argv_expanded[0]);
2813 /* XXX setup_redirects acts on file descriptors, not FILEs.
2814 * This is perfect for work that comes after exec().
2815 * Is it really safe for inline use? Experimentally,
2816 * things seem to work with glibc. */
2817 setup_redirects(command, squirrel);
2818 new_env = expand_assignments(argv, command->assignment_cnt);
2819 old_env = putenv_all_and_save_old(new_env);
2820 debug_printf_exec(": builtin '%s' '%s'...\n",
2821 x->cmd, argv_expanded[1]);
2822 rcode = x->function(argv_expanded) & 0xff;
2823 #if ENABLE_FEATURE_SH_STANDALONE
2826 restore_redirects(squirrel);
2827 free_strings_and_unsetenv(new_env, 1);
2828 putenv_all(old_env);
2829 free(old_env); /* not free_strings()! */
2831 free(argv_expanded);
2832 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2833 debug_printf_exec("run_pipe return %d\n", rcode);
2836 #if ENABLE_FEATURE_SH_STANDALONE
2837 i = find_applet_by_name(argv_expanded[0]);
2838 if (i >= 0 && APPLET_IS_NOFORK(i)) {
2839 setup_redirects(command, squirrel);
2840 save_nofork_data(&G.nofork_save);
2841 new_env = expand_assignments(argv, command->assignment_cnt);
2842 old_env = putenv_all_and_save_old(new_env);
2843 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
2844 argv_expanded[0], argv_expanded[1]);
2845 rcode = run_nofork_applet_prime(&G.nofork_save, i, argv_expanded);
2846 goto clean_up_and_ret;
2849 /* It is neither builtin nor applet. We must fork. */
2853 /* NB: argv_expanded may already be created, and that
2854 * might include `cmd` runs! Do not rerun it! We *must*
2855 * use argv_expanded if it's non-NULL */
2857 /* Going to fork a child per each pipe member */
2861 for (i = 0; i < pi->num_cmds; i++) {
2863 volatile nommu_save_t nommu_save;
2864 nommu_save.new_env = NULL;
2865 nommu_save.old_env = NULL;
2866 nommu_save.argv = NULL;
2868 command = &(pi->cmds[i]);
2869 if (command->argv) {
2870 debug_printf_exec(": pipe member '%s' '%s'...\n",
2871 command->argv[0], command->argv[1]);
2873 debug_printf_exec(": pipe member with no argv\n");
2876 /* pipes are inserted between pairs of commands */
2879 if ((i + 1) < pi->num_cmds)
2882 command->pid = BB_MMU ? fork() : vfork();
2883 if (!command->pid) { /* child */
2885 die_sleep = 0; /* let nofork's xfuncs die */
2887 /* Every child adds itself to new process group
2888 * with pgid == pid_of_first_child_in_pipe */
2889 if (G.run_list_level == 1 && G_interactive_fd) {
2892 if (pgrp < 0) /* true for 1st process only */
2894 if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
2895 /* We do it in *every* child, not just first,
2897 tcsetpgrp(G_interactive_fd, pgrp);
2901 xmove_fd(nextin, 0);
2902 xmove_fd(pipefds[1], 1); /* write end */
2904 close(pipefds[0]); /* read end */
2905 /* Like bash, explicit redirects override pipes,
2906 * and the pipe fd is available for dup'ing. */
2907 setup_redirects(command, NULL);
2909 /* Restore default handlers just prior to exec */
2910 /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
2912 /* Stores to nommu_save list of env vars putenv'ed
2913 * (NOMMU, on MMU we don't need that) */
2914 /* cast away volatility... */
2915 pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
2916 /* pseudo_exec() does not return */
2921 /* Clean up after vforked child */
2922 clean_up_after_re_execute();
2923 free(nommu_save.argv);
2924 free_strings_and_unsetenv(nommu_save.new_env, 1);
2925 putenv_all(nommu_save.old_env);
2927 free(argv_expanded);
2928 argv_expanded = NULL;
2929 if (command->pid < 0) { /* [v]fork failed */
2930 /* Clearly indicate, was it fork or vfork */
2931 bb_perror_msg(BB_MMU ? "fork" : "vfork");
2935 /* Second and next children need to know pid of first one */
2937 pi->pgrp = command->pid;
2943 if ((i + 1) < pi->num_cmds)
2944 close(pipefds[1]); /* write end */
2945 /* Pass read (output) pipe end to next iteration */
2946 nextin = pipefds[0];
2949 if (!pi->alive_cmds) {
2950 debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
2954 debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
2958 #ifndef debug_print_tree
2959 static void debug_print_tree(struct pipe *pi, int lvl)
2961 static const char *const PIPE[] = {
2967 static const char *RES[] = {
2968 [RES_NONE ] = "NONE" ,
2971 [RES_THEN ] = "THEN" ,
2972 [RES_ELIF ] = "ELIF" ,
2973 [RES_ELSE ] = "ELSE" ,
2976 #if ENABLE_HUSH_LOOPS
2977 [RES_FOR ] = "FOR" ,
2978 [RES_WHILE] = "WHILE",
2979 [RES_UNTIL] = "UNTIL",
2981 [RES_DONE ] = "DONE" ,
2983 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
2986 #if ENABLE_HUSH_CASE
2987 [RES_CASE ] = "CASE" ,
2988 [RES_MATCH] = "MATCH",
2989 [RES_CASEI] = "CASEI",
2990 [RES_ESAC ] = "ESAC" ,
2992 [RES_XXXX ] = "XXXX" ,
2993 [RES_SNTX ] = "SNTX" ,
2995 static const char *const GRPTYPE[] = {
2998 #if ENABLE_HUSH_FUNCTIONS
3007 fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
3008 pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
3010 while (prn < pi->num_cmds) {
3011 struct command *command = &pi->cmds[prn];
3012 char **argv = command->argv;
3014 fprintf(stderr, "%*s prog %d assignment_cnt:%d",
3016 command->assignment_cnt);
3017 if (command->group) {
3018 fprintf(stderr, " group %s: (argv=%p)\n",
3019 GRPTYPE[command->grp_type],
3021 debug_print_tree(command->group, lvl+1);
3025 if (argv) while (*argv) {
3026 fprintf(stderr, " '%s'", *argv);
3029 fprintf(stderr, "\n");
3038 /* NB: called by pseudo_exec, and therefore must not modify any
3039 * global data until exec/_exit (we can be a child after vfork!) */
3040 static int run_list(struct pipe *pi)
3042 #if ENABLE_HUSH_CASE
3043 char *case_word = NULL;
3045 #if ENABLE_HUSH_LOOPS
3046 struct pipe *loop_top = NULL;
3047 char *for_varname = NULL;
3048 char **for_lcur = NULL;
3049 char **for_list = NULL;
3051 smallint flag_skip = 1;
3052 smalluint rcode = 0; /* probably just for compiler */
3053 #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
3054 smalluint cond_code = 0;
3056 enum { cond_code = 0, };
3058 /*enum reserved_style*/ smallint rword = RES_NONE;
3059 /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
3061 debug_printf_exec("run_list start lvl %d\n", G.run_list_level + 1);
3063 #if ENABLE_HUSH_LOOPS
3064 /* Check syntax for "for" */
3065 for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
3066 if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
3068 /* current word is FOR or IN (BOLD in comments below) */
3069 if (cpipe->next == NULL) {
3070 syntax("malformed for");
3071 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3074 /* "FOR v; do ..." and "for v IN a b; do..." are ok */
3075 if (cpipe->next->res_word == RES_DO)
3077 /* next word is not "do". It must be "in" then ("FOR v in ...") */
3078 if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
3079 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
3081 syntax("malformed for");
3082 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3088 /* Past this point, all code paths should jump to ret: label
3089 * in order to return, no direct "return" statements please.
3090 * This helps to ensure that no memory is leaked. */
3092 ////TODO: ctrl-Z handling needs re-thinking and re-testing
3095 /* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
3096 * We are saving state before entering outermost list ("while...done")
3097 * so that ctrl-Z will correctly background _entire_ outermost list,
3098 * not just a part of it (like "sleep 1 | exit 2") */
3099 if (++G.run_list_level == 1 && G_interactive_fd) {
3100 if (sigsetjmp(G.toplevel_jb, 1)) {
3101 /* ctrl-Z forked and we are parent; or ctrl-C.
3102 * Sighandler has longjmped us here */
3103 signal(SIGINT, SIG_IGN);
3104 signal(SIGTSTP, SIG_IGN);
3105 /* Restore level (we can be coming from deep inside
3107 G.run_list_level = 1;
3108 #if ENABLE_FEATURE_SH_STANDALONE
3109 if (G.nofork_save.saved) { /* if save area is valid */
3110 debug_printf_jobs("exiting nofork early\n");
3111 restore_nofork_data(&G.nofork_save);
3114 //// if (G.ctrl_z_flag) {
3115 //// /* ctrl-Z has forked and stored pid of the child in pi->pid.
3116 //// * Remember this child as background job */
3117 //// insert_bg_job(pi);
3119 /* ctrl-C. We just stop doing whatever we were doing */
3122 USE_HUSH_LOOPS(loop_top = NULL;)
3123 USE_HUSH_LOOPS(G.depth_of_loop = 0;)
3127 //// /* ctrl-Z handler will store pid etc in pi */
3128 //// G.toplevel_list = pi;
3129 //// G.ctrl_z_flag = 0;
3130 ////#if ENABLE_FEATURE_SH_STANDALONE
3131 //// G.nofork_save.saved = 0; /* in case we will run a nofork later */
3133 //// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
3134 //// signal(SIGINT, handler_ctrl_c);
3138 /* Go through list of pipes, (maybe) executing them. */
3139 for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
3143 IF_HAS_KEYWORDS(rword = pi->res_word;)
3144 IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
3145 debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
3146 rword, cond_code, skip_more_for_this_rword);
3147 #if ENABLE_HUSH_LOOPS
3148 if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
3149 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
3151 /* start of a loop: remember where loop starts */
3156 if (rword == skip_more_for_this_rword && flag_skip) {
3157 if (pi->followup == PIPE_SEQ)
3159 /* it is "<false> && CMD" or "<true> || CMD"
3160 * and we should not execute CMD */
3164 skip_more_for_this_rword = RES_XXXX;
3167 if (rword == RES_THEN) {
3168 /* "if <false> THEN cmd": skip cmd */
3172 if (rword == RES_ELSE || rword == RES_ELIF) {
3173 /* "if <true> then ... ELSE/ELIF cmd":
3174 * skip cmd and all following ones */
3179 #if ENABLE_HUSH_LOOPS
3180 if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
3182 /* first loop through for */
3184 static const char encoded_dollar_at[] ALIGN1 = {
3185 SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
3186 }; /* encoded representation of "$@" */
3187 static const char *const encoded_dollar_at_argv[] = {
3188 encoded_dollar_at, NULL
3189 }; /* argv list with one element: "$@" */
3192 vals = (char**)encoded_dollar_at_argv;
3193 if (pi->next->res_word == RES_IN) {
3194 /* if no variable values after "in" we skip "for" */
3195 if (!pi->next->cmds[0].argv)
3197 vals = pi->next->cmds[0].argv;
3198 } /* else: "for var; do..." -> assume "$@" list */
3199 /* create list of variable values */
3200 debug_print_strings("for_list made from", vals);
3201 for_list = expand_strvec_to_strvec(vals);
3202 for_lcur = for_list;
3203 debug_print_strings("for_list", for_list);
3204 for_varname = pi->cmds[0].argv[0];
3205 pi->cmds[0].argv[0] = NULL;
3207 free(pi->cmds[0].argv[0]);
3209 /* "for" loop is over, clean up */
3213 pi->cmds[0].argv[0] = for_varname;
3216 /* insert next value from for_lcur */
3217 //TODO: does it need escaping?
3218 pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
3219 pi->cmds[0].assignment_cnt = 1;
3221 if (rword == RES_IN) {
3222 continue; /* "for v IN list;..." - "in" has no cmds anyway */
3224 if (rword == RES_DONE) {
3225 continue; /* "done" has no cmds too */
3228 #if ENABLE_HUSH_CASE
3229 if (rword == RES_CASE) {
3230 case_word = expand_strvec_to_string(pi->cmds->argv);
3233 if (rword == RES_MATCH) {
3236 if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
3238 /* all prev words didn't match, does this one match? */
3239 argv = pi->cmds->argv;
3241 char *pattern = expand_string_to_string(*argv);
3242 /* TODO: which FNM_xxx flags to use? */
3243 cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
3245 if (cond_code == 0) { /* match! we will execute this branch */
3246 free(case_word); /* make future "word)" stop */
3254 if (rword == RES_CASEI) { /* inside of a case branch */
3256 continue; /* not matched yet, skip this pipe */
3259 /* Just pressing <enter> in shell should check for jobs.
3260 * OTOH, in non-interactive shell this is useless
3261 * and only leads to extra job checks */
3262 if (pi->num_cmds == 0) {
3263 if (G_interactive_fd)
3264 goto check_jobs_and_continue;
3268 /* After analyzing all keywords and conditions, we decided
3269 * to execute this pipe. NB: have to do checkjobs(NULL)
3270 * after run_pipe() to collect any background children,
3271 * even if list execution is to be stopped. */
3272 debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
3275 #if ENABLE_HUSH_LOOPS
3276 G.flag_break_continue = 0;
3278 rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
3280 /* we only ran a builtin: rcode is already known
3281 * and we don't need to wait for anything. */
3282 check_and_run_traps(0);
3283 #if ENABLE_HUSH_LOOPS
3284 /* was it "break" or "continue"? */
3285 if (G.flag_break_continue) {
3286 smallint fbc = G.flag_break_continue;
3287 /* we might fall into outer *loop*,
3288 * don't want to break it too */
3290 G.depth_break_continue--;
3291 if (G.depth_break_continue == 0)
3292 G.flag_break_continue = 0;
3293 /* else: e.g. "continue 2" should *break* once, *then* continue */
3294 } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
3295 if (G.depth_break_continue != 0 || fbc == BC_BREAK)
3296 goto check_jobs_and_break;
3297 /* "continue": simulate end of loop */
3302 } else if (pi->followup == PIPE_BG) {
3303 /* what does bash do with attempts to background builtins? */
3304 /* even bash 3.2 doesn't do that well with nested bg:
3305 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
3306 * I'm NOT treating inner &'s as jobs */
3307 check_and_run_traps(0);
3309 if (G.run_list_level == 1)
3312 rcode = 0; /* EXIT_SUCCESS */
3315 if (G.run_list_level == 1 && G_interactive_fd) {
3316 /* waits for completion, then fg's main shell */
3317 rcode = checkjobs_and_fg_shell(pi);
3318 check_and_run_traps(0);
3319 debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
3322 { /* this one just waits for completion */
3323 rcode = checkjobs(pi);
3324 check_and_run_traps(0);
3325 debug_printf_exec(": checkjobs returned %d\n", rcode);
3329 debug_printf_exec(": setting last_return_code=%d\n", rcode);
3330 G.last_return_code = rcode;
3332 /* Analyze how result affects subsequent commands */
3334 if (rword == RES_IF || rword == RES_ELIF)
3337 #if ENABLE_HUSH_LOOPS
3338 if (rword == RES_WHILE) {
3340 rcode = 0; /* "while false; do...done" - exitcode 0 */
3341 goto check_jobs_and_break;
3344 if (rword == RES_UNTIL) {
3346 check_jobs_and_break:
3352 if ((rcode == 0 && pi->followup == PIPE_OR)
3353 || (rcode != 0 && pi->followup == PIPE_AND)
3355 skip_more_for_this_rword = rword;
3358 check_jobs_and_continue:
3363 //// if (G.ctrl_z_flag) {
3364 //// /* ctrl-Z forked somewhere in the past, we are the child,
3365 //// * and now we completed running the list. Exit. */
3371 //// if (!G.run_list_level && G_interactive_fd) {
3372 //// signal(SIGTSTP, SIG_IGN);
3373 //// signal(SIGINT, SIG_IGN);
3376 debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
3377 #if ENABLE_HUSH_LOOPS
3382 #if ENABLE_HUSH_CASE
3388 /* Select which version we will use */
3389 static int run_and_free_list(struct pipe *pi)
3392 debug_printf_exec("run_and_free_list entered\n");
3394 debug_printf_exec(": run_list with %d members\n", pi->num_cmds);
3395 rcode = run_list(pi);
3397 /* free_pipe_list has the side effect of clearing memory.
3398 * In the long run that function can be merged with run_list,
3399 * but doing that now would hobble the debugging effort. */
3400 free_pipe_list(pi, /* indent: */ 0);
3401 debug_printf_exec("run_and_free_list return %d\n", rcode);
3406 /* Peek ahead in the in_str to find out if we have a "&n" construct,
3407 * as in "2>&1", that represents duplicating a file descriptor.
3408 * Return either -2 (syntax error), -1 (no &), or the number found.
3410 static int redirect_dup_num(struct in_str *input)
3412 int ch, d = 0, ok = 0;
3414 if (ch != '&') return -1;
3416 i_getch(input); /* get the & */
3420 return -3; /* "-" represents "close me" */
3422 while (isdigit(ch)) {
3423 d = d*10 + (ch-'0');
3430 bb_error_msg("ambiguous redirect");
3434 /* The src parameter allows us to peek forward to a possible &n syntax
3435 * for file descriptor duplication, e.g., "2>&1".
3436 * Return code is 0 normally, 1 if a syntax error is detected in src.
3437 * Resource errors (in xmalloc) cause the process to exit */
3438 static int setup_redirect(struct parse_context *ctx,
3441 struct in_str *input)
3443 struct command *command = ctx->command;
3444 struct redir_struct *redir;
3445 struct redir_struct **redirp;
3448 /* Check for a '2>&1' type redirect */
3449 dup_num = redirect_dup_num(input);
3451 return 1; /* syntax error */
3453 /* Create a new redir_struct and drop it onto the end of the linked list */
3454 redirp = &command->redirects;
3455 while ((redir = *redirp) != NULL) {
3456 redirp = &(redir->next);
3458 *redirp = redir = xzalloc(sizeof(*redir));
3459 /* redir->next = NULL; */
3460 /* redir->rd_filename = NULL; */
3461 redir->rd_type = style;
3462 redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
3464 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
3466 redir->dup = dup_num;
3467 if (dup_num != -1) {
3468 /* Erik had a check here that the file descriptor in question
3469 * is legit; I postpone that to "run time"
3470 * A "-" representation of "close me" shows up as a -3 here */
3471 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
3473 /* We do _not_ try to open the file that src points to,
3474 * since we need to return and let src be expanded first.
3475 * Set ctx->pending_redirect, so we know what to do at the
3476 * end of the next parsed word. */
3477 ctx->pending_redirect = redir;
3483 static struct pipe *new_pipe(void)
3486 pi = xzalloc(sizeof(struct pipe));
3487 /*pi->followup = 0; - deliberately invalid value */
3488 /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
3492 /* Command (member of a pipe) is complete. The only possible error here
3493 * is out of memory, in which case xmalloc exits. */
3494 static int done_command(struct parse_context *ctx)
3496 /* The command is really already in the pipe structure, so
3497 * advance the pipe counter and make a new, null command. */
3498 struct pipe *pi = ctx->pipe;
3499 struct command *command = ctx->command;
3502 if (command->group == NULL
3503 && command->argv == NULL
3504 && command->redirects == NULL
3506 debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
3507 return pi->num_cmds;
3510 debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
3512 debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
3515 /* Only real trickiness here is that the uncommitted
3516 * command structure is not counted in pi->num_cmds. */
3517 pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
3518 command = &pi->cmds[pi->num_cmds];
3519 memset(command, 0, sizeof(*command));
3521 ctx->command = command;
3522 /* but ctx->pipe and ctx->list_head remain unchanged */
3524 return pi->num_cmds; /* used only for 0/nonzero check */
3527 static void done_pipe(struct parse_context *ctx, pipe_style type)
3531 debug_printf_parse("done_pipe entered, followup %d\n", type);
3532 /* Close previous command */
3533 not_null = done_command(ctx);
3534 ctx->pipe->followup = type;
3535 IF_HAS_KEYWORDS(ctx->pipe->pi_inverted = ctx->ctx_inverted;)
3536 IF_HAS_KEYWORDS(ctx->ctx_inverted = 0;)
3537 IF_HAS_KEYWORDS(ctx->pipe->res_word = ctx->ctx_res_w;)
3539 /* Without this check, even just <enter> on command line generates
3540 * tree of three NOPs (!). Which is harmless but annoying.
3541 * IOW: it is safe to do it unconditionally.
3542 * RES_NONE case is for "for a in; do ..." (empty IN set)
3543 * to work, possibly other cases too. */
3544 if (not_null IF_HAS_KEYWORDS(|| ctx->ctx_res_w != RES_NONE)) {
3546 debug_printf_parse("done_pipe: adding new pipe: "
3547 "not_null:%d ctx->ctx_res_w:%d\n",
3548 not_null, ctx->ctx_res_w);
3550 ctx->pipe->next = new_p;
3552 /* RES_THEN, RES_DO etc are "sticky" -
3553 * they remain set for commands inside if/while.
3554 * This is used to control execution.
3555 * RES_FOR and RES_IN are NOT sticky (needed to support
3556 * cases where variable or value happens to match a keyword):
3558 #if ENABLE_HUSH_LOOPS
3559 if (ctx->ctx_res_w == RES_FOR
3560 || ctx->ctx_res_w == RES_IN)
3561 ctx->ctx_res_w = RES_NONE;
3563 #if ENABLE_HUSH_CASE
3564 if (ctx->ctx_res_w == RES_MATCH)
3565 ctx->ctx_res_w = RES_CASEI;
3567 ctx->command = NULL; /* trick done_command below */
3568 /* Create the memory for command, roughly:
3569 * ctx->pipe->cmds = new struct command;
3570 * ctx->command = &ctx->pipe->cmds[0];
3574 debug_printf_parse("done_pipe return\n");
3577 static void initialize_context(struct parse_context *ctx)
3579 memset(ctx, 0, sizeof(*ctx));
3580 ctx->pipe = ctx->list_head = new_pipe();
3581 /* Create the memory for command, roughly:
3582 * ctx->pipe->cmds = new struct command;
3583 * ctx->command = &ctx->pipe->cmds[0];
3589 /* If a reserved word is found and processed, parse context is modified
3590 * and 1 is returned.
3593 struct reserved_combo {
3596 unsigned char assignment_flag;
3600 FLAG_END = (1 << RES_NONE ),
3602 FLAG_IF = (1 << RES_IF ),
3603 FLAG_THEN = (1 << RES_THEN ),
3604 FLAG_ELIF = (1 << RES_ELIF ),
3605 FLAG_ELSE = (1 << RES_ELSE ),
3606 FLAG_FI = (1 << RES_FI ),
3608 #if ENABLE_HUSH_LOOPS
3609 FLAG_FOR = (1 << RES_FOR ),
3610 FLAG_WHILE = (1 << RES_WHILE),
3611 FLAG_UNTIL = (1 << RES_UNTIL),
3612 FLAG_DO = (1 << RES_DO ),
3613 FLAG_DONE = (1 << RES_DONE ),
3614 FLAG_IN = (1 << RES_IN ),
3616 #if ENABLE_HUSH_CASE
3617 FLAG_MATCH = (1 << RES_MATCH),
3618 FLAG_ESAC = (1 << RES_ESAC ),
3620 FLAG_START = (1 << RES_XXXX ),
3623 static const struct reserved_combo* match_reserved_word(o_string *word)
3625 /* Mostly a list of accepted follow-up reserved words.
3626 * FLAG_END means we are done with the sequence, and are ready
3627 * to turn the compound list into a command.
3628 * FLAG_START means the word must start a new compound list.
3630 static const struct reserved_combo reserved_list[] = {
3632 { "!", RES_NONE, NOT_ASSIGNMENT , 0 },
3633 { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START },
3634 { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
3635 { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN },
3636 { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI },
3637 { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
3639 #if ENABLE_HUSH_LOOPS
3640 { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
3641 { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3642 { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3643 { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
3644 { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE },
3645 { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
3647 #if ENABLE_HUSH_CASE
3648 { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
3649 { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
3652 const struct reserved_combo *r;
3654 for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
3655 if (strcmp(word->data, r->literal) == 0)
3660 static int reserved_word(o_string *word, struct parse_context *ctx)
3662 #if ENABLE_HUSH_CASE
3663 static const struct reserved_combo reserved_match = {
3664 "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
3667 const struct reserved_combo *r;
3669 r = match_reserved_word(word);
3673 debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
3674 #if ENABLE_HUSH_CASE
3675 if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE)
3676 /* "case word IN ..." - IN part starts first match part */
3677 r = &reserved_match;
3680 if (r->flag == 0) { /* '!' */
3681 if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
3682 syntax("! ! command");
3683 IF_HAS_KEYWORDS(ctx->ctx_res_w = RES_SNTX;)
3685 ctx->ctx_inverted = 1;
3688 if (r->flag & FLAG_START) {
3689 struct parse_context *old;
3690 old = xmalloc(sizeof(*old));
3691 debug_printf_parse("push stack %p\n", old);
3692 *old = *ctx; /* physical copy */
3693 initialize_context(ctx);
3695 } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
3697 ctx->ctx_res_w = RES_SNTX;
3700 ctx->ctx_res_w = r->res;
3701 ctx->old_flag = r->flag;
3702 if (ctx->old_flag & FLAG_END) {
3703 struct parse_context *old;
3704 done_pipe(ctx, PIPE_SEQ);
3705 debug_printf_parse("pop stack %p\n", ctx->stack);
3707 old->command->group = ctx->list_head;
3708 old->command->grp_type = GRP_NORMAL;
3710 o_addstr(&old->as_string, ctx->as_string.data);
3711 o_free_unsafe(&ctx->as_string);
3712 old->command->group_as_string = xstrdup(old->as_string.data);
3713 debug_printf_parse("pop, remembering as:'%s'\n",
3714 old->command->group_as_string);
3716 *ctx = *old; /* physical copy */
3719 word->o_assignment = r->assignment_flag;
3724 /* Word is complete, look at it and update parsing context.
3725 * Normal return is 0. Syntax errors return 1.
3726 * Note: on return, word is reset, but not o_free'd!
3728 static int done_word(o_string *word, struct parse_context *ctx)
3730 struct command *command = ctx->command;
3732 debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
3733 if (word->length == 0 && word->nonnull == 0) {
3734 debug_printf_parse("done_word return 0: true null, ignored\n");
3737 /* If this word wasn't an assignment, next ones definitely
3738 * can't be assignments. Even if they look like ones. */
3739 if (word->o_assignment != DEFINITELY_ASSIGNMENT
3740 && word->o_assignment != WORD_IS_KEYWORD
3742 word->o_assignment = NOT_ASSIGNMENT;
3744 if (word->o_assignment == DEFINITELY_ASSIGNMENT)
3745 command->assignment_cnt++;
3746 word->o_assignment = MAYBE_ASSIGNMENT;
3749 if (ctx->pending_redirect) {
3750 /* We do not glob in e.g. >*.tmp case. bash seems to glob here
3751 * only if run as "bash", not "sh" */
3752 ctx->pending_redirect->rd_filename = xstrdup(word->data);
3753 word->o_assignment = NOT_ASSIGNMENT;
3754 debug_printf("word stored in rd_filename: '%s'\n", word->data);
3756 /* "{ echo foo; } echo bar" - bad */
3757 /* NB: bash allows e.g.:
3758 * if true; then { echo foo; } fi
3759 * while if false; then false; fi do break; done
3761 if (command->group) {
3763 debug_printf_parse("done_word return 1: syntax error, "
3764 "groups and arglists don't mix\n");
3768 #if ENABLE_HUSH_CASE
3769 if (ctx->ctx_dsemicolon
3770 && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
3772 /* already done when ctx_dsemicolon was set to 1: */
3773 /* ctx->ctx_res_w = RES_MATCH; */
3774 ctx->ctx_dsemicolon = 0;
3777 if (!command->argv /* if it's the first word... */
3778 #if ENABLE_HUSH_LOOPS
3779 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
3780 && ctx->ctx_res_w != RES_IN
3783 debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
3784 if (reserved_word(word, ctx)) {
3786 debug_printf_parse("done_word return %d\n",
3787 (ctx->ctx_res_w == RES_SNTX));
3788 return (ctx->ctx_res_w == RES_SNTX);
3792 if (word->nonnull /* word had "xx" or 'xx' at least as part of it. */
3793 /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
3794 && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
3795 /* (otherwise it's known to be not empty and is already safe) */
3797 /* exclude "$@" - it can expand to no word despite "" */
3798 char *p = word->data;
3799 while (p[0] == SPECIAL_VAR_SYMBOL
3800 && (p[1] & 0x7f) == '@'
3801 && p[2] == SPECIAL_VAR_SYMBOL
3805 if (p == word->data || p[0] != '\0') {
3806 /* saw no "$@", or not only "$@" but some
3807 * real text is there too */
3808 /* insert "empty variable" reference, this makes
3809 * e.g. "", $empty"" etc to not disappear */
3810 o_addchr(word, SPECIAL_VAR_SYMBOL);
3811 o_addchr(word, SPECIAL_VAR_SYMBOL);
3814 command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
3815 debug_print_strings("word appended to argv", command->argv);
3819 ctx->pending_redirect = NULL;
3821 #if ENABLE_HUSH_LOOPS
3822 /* Force FOR to have just one word (variable name) */
3823 /* NB: basically, this makes hush see "for v in ..." syntax as if
3824 * as it is "for v; in ...". FOR and IN become two pipe structs
3826 if (ctx->ctx_res_w == RES_FOR) {
3827 //TODO: check that command->argv[0] is a valid variable name!
3828 done_pipe(ctx, PIPE_SEQ);
3831 #if ENABLE_HUSH_CASE
3832 /* Force CASE to have just one word */
3833 if (ctx->ctx_res_w == RES_CASE) {
3834 done_pipe(ctx, PIPE_SEQ);
3837 debug_printf_parse("done_word return 0\n");
3841 /* If a redirect is immediately preceded by a number, that number is
3842 * supposed to tell which file descriptor to redirect. This routine
3843 * looks for such preceding numbers. In an ideal world this routine
3844 * needs to handle all the following classes of redirects...
3845 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
3846 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
3847 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
3848 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
3849 * A -1 output from this program means no valid number was found, so the
3850 * caller should use the appropriate default for this redirection.
3852 static int redirect_opt_num(o_string *o)
3858 for (num = 0; num < o->length; num++) {
3859 if (!isdigit(o->data[num])) {
3863 num = atoi(o->data);
3869 #define parse_stream(pstring, input, end_trigger) \
3870 parse_stream(input, end_trigger)
3872 static struct pipe *parse_stream(char **pstring,
3873 struct in_str *input,
3875 static void parse_and_run_string(const char *s);
3877 #if ENABLE_HUSH_TICK
3878 static FILE *generate_stream_from_string(const char *s)
3881 int pid, channel[2];
3884 pid = BB_MMU ? fork() : vfork();
3886 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
3888 if (pid == 0) { /* child */
3889 /* Process substitution is not considered to be usual
3890 * 'command execution'.
3891 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
3898 if (ENABLE_HUSH_JOB)
3899 die_sleep = 0; /* let nofork's xfuncs die */
3900 close(channel[0]); /* NB: close _first_, then move fd! */
3901 xmove_fd(channel[1], 1);
3902 /* Prevent it from trying to handle ctrl-z etc */
3903 USE_HUSH_JOB(G.run_list_level = 1;)
3905 parse_and_run_string(s);
3906 _exit(G.last_return_code);
3908 /* We re-execute after vfork on NOMMU. This makes this script safe:
3909 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >TESTFILE
3910 * huge=`cat TESTFILE` # was blocking here forever
3913 re_execute_shell(s);
3918 clean_up_after_re_execute();
3920 pf = fdopen(channel[0], "r");
3924 /* Return code is exit status of the process that is run. */
3925 static int process_command_subs(o_string *dest, const char *s)
3928 struct in_str pipe_str;
3931 pf = generate_stream_from_string(s);
3934 close_on_exec_on(fileno(pf));
3936 /* Now send results of command back into original context */
3937 setup_file_in_str(&pipe_str, pf);
3939 while ((ch = i_getch(&pipe_str)) != EOF) {
3945 o_addchr(dest, '\n');
3948 o_addQchr(dest, ch);
3951 debug_printf("done reading from pipe, pclose()ing\n");
3952 /* Note: we got EOF, and we just close the read end of the pipe.
3953 * We do not wait for the `cmd` child to terminate. bash and ash do.
3955 * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec
3956 * `false`; echo $? - bash outputs "1"
3959 debug_printf("closed FILE from child. return 0\n");
3964 static int parse_group(o_string *dest, struct parse_context *ctx,
3965 struct in_str *input, int ch)
3967 /* dest contains characters seen prior to ( or {.
3968 * Typically it's empty, but for function defs,
3969 * it contains function name (without '()'). */
3970 struct pipe *pipe_list;
3972 struct command *command = ctx->command;
3974 debug_printf_parse("parse_group entered\n");
3975 #if ENABLE_HUSH_FUNCTIONS
3976 if (ch == 'F') { /* function definition? */
3977 bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
3978 //command->fname = dest->data;
3979 command->grp_type = GRP_FUNCTION;
3980 //TODO: review every o_reset() location... do they handle all o_string fields correctly?
3981 memset(dest, 0, sizeof(*dest));
3984 if (command->argv /* word [word](... */
3985 || dest->length /* word(... */
3986 || dest->nonnull /* ""(... */
3989 debug_printf_parse("parse_group return 1: "
3990 "syntax error, groups and arglists don't mix\n");
3996 command->grp_type = GRP_SUBSHELL;
4000 char *as_string = NULL;
4002 pipe_list = parse_stream(&as_string, input, endch);
4005 o_addstr(&ctx->as_string, as_string);
4007 /* empty ()/{} or parse error? */
4008 if (!pipe_list || pipe_list == ERR_PTR) {
4013 debug_printf_parse("parse_group return 1: "
4014 "parse_stream returned %p\n", pipe_list);
4017 command->group = pipe_list;
4019 as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
4020 command->group_as_string = as_string;
4021 debug_printf_parse("end of group, remembering as:'%s'\n",
4022 command->group_as_string);
4025 debug_printf_parse("parse_group return 0\n");
4027 /* command remains "open", available for possible redirects */
4030 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
4031 /* Subroutines for copying $(...) and `...` things */
4032 static void add_till_backquote(o_string *dest, struct in_str *input);
4034 static void add_till_single_quote(o_string *dest, struct in_str *input)
4037 int ch = i_getch(input);
4045 /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
4046 static void add_till_double_quote(o_string *dest, struct in_str *input)
4049 int ch = i_getch(input);
4052 if (ch == '\\') { /* \x. Copy both chars. */
4054 ch = i_getch(input);
4060 add_till_backquote(dest, input);
4064 //if (ch == '$') ...
4067 /* Process `cmd` - copy contents until "`" is seen. Complicated by
4069 * "Within the backquoted style of command substitution, backslash
4070 * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
4071 * The search for the matching backquote shall be satisfied by the first
4072 * backquote found without a preceding backslash; during this search,
4073 * if a non-escaped backquote is encountered within a shell comment,
4074 * a here-document, an embedded command substitution of the $(command)
4075 * form, or a quoted string, undefined results occur. A single-quoted
4076 * or double-quoted string that begins, but does not end, within the
4077 * "`...`" sequence produces undefined results."
4079 * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
4081 static void add_till_backquote(o_string *dest, struct in_str *input)
4084 int ch = i_getch(input);
4087 if (ch == '\\') { /* \x. Copy both chars unless it is \` */
4088 int ch2 = i_getch(input);
4089 if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
4098 /* Process $(cmd) - copy contents until ")" is seen. Complicated by
4099 * quoting and nested ()s.
4100 * "With the $(command) style of command substitution, all characters
4101 * following the open parenthesis to the matching closing parenthesis
4102 * constitute the command. Any valid shell script can be used for command,
4103 * except a script consisting solely of redirections which produces
4104 * unspecified results."
4106 * echo $(echo '(TEST)' BEST) (TEST) BEST
4107 * echo $(echo 'TEST)' BEST) TEST) BEST
4108 * echo $(echo \(\(TEST\) BEST) ((TEST) BEST
4110 static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
4114 int ch = i_getch(input);
4123 if (i_peek(input) == ')') {
4131 add_till_single_quote(dest, input);
4136 add_till_double_quote(dest, input);
4140 if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */
4141 ch = i_getch(input);
4149 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
4151 /* Return code: 0 for OK, 1 for syntax error */
4153 #define handle_dollar(ctx, dest, input) \
4154 handle_dollar(dest, input)
4156 static int handle_dollar(struct parse_context *ctx,
4158 struct in_str *input)
4161 int ch = i_peek(input); /* first character after the $ */
4162 unsigned char quote_mask = dest->o_escape ? 0x80 : 0;
4164 debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
4166 ch = i_getch(input);
4168 if (ctx) o_addchr(&ctx->as_string, ch);
4171 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4173 debug_printf_parse(": '%c'\n", ch);
4174 o_addchr(dest, ch | quote_mask);
4177 if (!isalnum(ch) && ch != '_')
4179 ch = i_getch(input);
4181 if (ctx) o_addchr(&ctx->as_string, ch);
4184 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4185 } else if (isdigit(ch)) {
4187 ch = i_getch(input);
4189 if (ctx) o_addchr(&ctx->as_string, ch);
4191 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4192 debug_printf_parse(": '%c'\n", ch);
4193 o_addchr(dest, ch | quote_mask);
4194 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4195 } else switch (ch) {
4197 case '!': /* last bg pid */
4198 case '?': /* last exit code */
4199 case '#': /* number of args */
4200 case '*': /* args */
4201 case '@': /* args */
4202 goto make_one_char_var;
4204 bool first_char, all_digits;
4206 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4207 ch = i_getch(input);
4209 if (ctx) o_addchr(&ctx->as_string, ch);
4211 /* XXX maybe someone will try to escape the '}' */
4216 ch = i_getch(input);
4218 if (ctx) o_addchr(&ctx->as_string, ch);
4225 /* ${#var}: length of var contents */
4227 else if (isdigit(ch)) {
4234 && ( (all_digits && !isdigit(ch))
4235 || (!all_digits && !isalnum(ch) && ch != '_')
4238 /* handle parameter expansions
4239 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
4244 case ':': /* null modifier */
4245 if (expansion == 0) {
4246 debug_printf_parse(": null modifier\n");
4251 #if 0 /* not implemented yet :( */
4252 case '#': /* remove prefix */
4253 case '%': /* remove suffix */
4254 if (expansion == 0) {
4255 debug_printf_parse(": remove suffix/prefix\n");
4261 case '-': /* default value */
4262 case '=': /* assign default */
4263 case '+': /* alternative */
4264 case '?': /* error indicate */
4265 debug_printf_parse(": parameter expansion\n");
4270 syntax("unterminated ${name}");
4271 debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
4276 debug_printf_parse(": '%c'\n", ch);
4277 o_addchr(dest, ch | quote_mask);
4281 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4288 ch = i_getch(input);
4290 if (ctx) o_addchr(&ctx->as_string, ch);
4292 #if ENABLE_SH_MATH_SUPPORT
4293 if (i_peek(input) == '(') {
4294 ch = i_getch(input);
4296 if (ctx) o_addchr(&ctx->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(&ctx->as_string, dest->data + pos);
4307 o_addchr(&ctx->as_string, ')');
4308 o_addchr(&ctx->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(&ctx->as_string, dest->data + pos);
4326 o_addchr(&ctx->as_string, '`');
4329 //debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
4330 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4335 ch = i_getch(input);
4337 if (ctx) o_addchr(&ctx->as_string, ch);
4340 if (isalnum(ch)) { /* it's $_name or $_123 */
4346 /* $_ Shell or shell script name; or last cmd name */
4347 /* $- Option flags set by set builtin or shell options (-i etc) */
4349 o_addQchr(dest, '$');
4351 debug_printf_parse("handle_dollar return 0\n");
4356 #define parse_stream_dquoted(ctx, dest, input, dquote_end) \
4357 parse_stream_dquoted(dest, input, dquote_end)
4359 static int parse_stream_dquoted(struct parse_context *ctx,
4361 struct in_str *input,
4368 ch = i_getch(input);
4370 if (ctx && ch != EOF)
4371 o_addchr(&ctx->as_string, ch);
4373 if (ch == dquote_end) { /* may be only '"' or EOF */
4375 if (dest->o_assignment == NOT_ASSIGNMENT)
4376 dest->o_escape ^= 1;
4377 debug_printf_parse("parse_stream_dquoted return 0\n");
4381 syntax("unterminated \"");
4382 debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n");
4387 next = i_peek(input);
4389 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4390 ch, ch, dest->o_escape);
4394 debug_printf_parse("parse_stream_dquoted return 1: \\<eof>\n");
4398 * "The backslash retains its special meaning [in "..."]
4399 * only when followed by one of the following characters:
4400 * $, `, ", \, or <newline>. A double quote may be quoted
4401 * within double quotes by preceding it with a backslash.
4402 * If enabled, history expansion will be performed unless
4403 * an ! appearing in double quotes is escaped using
4404 * a backslash. The backslash preceding the ! is not removed."
4406 if (strchr("$`\"\\", next) != NULL) {
4407 o_addqchr(dest, i_getch(input));
4409 o_addqchr(dest, '\\');
4414 if (handle_dollar(ctx, dest, input) != 0) {
4415 debug_printf_parse("parse_stream_dquoted return 1: "
4416 "handle_dollar returned non-0\n");
4421 #if ENABLE_HUSH_TICK
4423 //int pos = dest->length;
4424 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4425 o_addchr(dest, 0x80 | '`');
4426 add_till_backquote(dest, input);
4427 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4428 //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
4432 o_addQchr(dest, ch);
4434 && (dest->o_assignment == MAYBE_ASSIGNMENT
4435 || dest->o_assignment == WORD_IS_KEYWORD)
4436 && is_assignment(dest->data)
4438 dest->o_assignment = DEFINITELY_ASSIGNMENT;
4444 * Scan input until EOF or end_trigger char.
4445 * Return a list of pipes to execute, or NULL on EOF
4446 * or if end_trigger character is met.
4447 * On syntax error, exit is shell is not interactive,
4448 * reset parsing machinery and start parsing anew,
4449 * or return ERR_PTR.
4451 static struct pipe *parse_stream(char **pstring,
4452 struct in_str *input,
4455 struct parse_context ctx;
4456 o_string dest = NULL_O_STRING;
4459 /* Double-quote state is handled in the state variable is_in_dquote.
4460 * A single-quote triggers a bypass of the main loop until its mate is
4461 * found. When recursing, quote state is passed in via dest->o_escape.
4463 debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
4464 end_trigger ? : 'X');
4466 G.ifs = get_local_var_value("IFS");
4471 #if ENABLE_HUSH_INTERACTIVE
4472 input->promptmode = 0; /* PS1 */
4474 /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */
4475 initialize_context(&ctx);
4479 const char *is_special;
4483 redir_type redir_style;
4486 if (parse_stream_dquoted(&ctx, &dest, input, '"')) {
4489 /* We reached closing '"' */
4492 ch = i_getch(input);
4493 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4494 ch, ch, dest.o_escape);
4497 if (done_word(&dest, &ctx)) {
4501 done_pipe(&ctx, PIPE_SEQ);
4503 /* If we got nothing... */
4504 // TODO: test script consisting of just "&"
4505 if (pi->num_cmds == 0
4506 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
4508 free_pipe_list(pi, 0);
4511 debug_printf_parse("parse_stream return %p\n", pi);
4513 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4515 *pstring = ctx.as_string.data;
4517 o_free_unsafe(&ctx.as_string);
4522 o_addchr(&ctx.as_string, ch);
4524 is_ifs = strchr(G.ifs, ch);
4525 is_special = strchr("<>;&|(){}#'" /* special outside of "str" */
4526 "\\$\"" USE_HUSH_TICK("`") /* always special */
4529 if (!is_special && !is_ifs) { /* ordinary char */
4530 o_addQchr(&dest, ch);
4531 if ((dest.o_assignment == MAYBE_ASSIGNMENT
4532 || dest.o_assignment == WORD_IS_KEYWORD)
4534 && is_assignment(dest.data)
4536 dest.o_assignment = DEFINITELY_ASSIGNMENT;
4542 if (done_word(&dest, &ctx)) {
4546 #if ENABLE_HUSH_CASE
4547 /* "case ... in <newline> word) ..." -
4548 * newlines are ignored (but ';' wouldn't be) */
4549 if (ctx.command->argv == NULL
4550 && ctx.ctx_res_w == RES_MATCH
4555 /* Treat newline as a command separator. */
4556 done_pipe(&ctx, PIPE_SEQ);
4557 dest.o_assignment = MAYBE_ASSIGNMENT;
4559 /* note: if (is_ifs) continue;
4560 * will still trigger for us */
4563 if (end_trigger && end_trigger == ch) {
4564 //TODO: disallow "{ cmd }" without semicolon
4565 if (done_word(&dest, &ctx)) {
4568 done_pipe(&ctx, PIPE_SEQ);
4569 dest.o_assignment = MAYBE_ASSIGNMENT;
4570 /* Do we sit outside of any if's, loops or case's? */
4572 IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
4574 debug_printf_parse("parse_stream return %p: "
4575 "end_trigger char found\n",
4579 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4581 *pstring = ctx.as_string.data;
4583 o_free_unsafe(&ctx.as_string);
4585 return ctx.list_head;
4591 if (dest.o_assignment == MAYBE_ASSIGNMENT) {
4592 /* ch is a special char and thus this word
4593 * cannot be an assignment */
4594 dest.o_assignment = NOT_ASSIGNMENT;
4599 next = i_peek(input);
4604 if (dest.length == 0) {
4607 if (ch == EOF || ch == '\n')
4610 /* note: we do not add it to &ctx.as_string */
4613 //TODO: go back one char?
4614 o_addchr(&ctx.as_string, '\n');
4617 o_addQchr(&dest, ch);
4625 o_addchr(&dest, '\\');
4626 ch = i_getch(input);
4627 o_addchr(&dest, ch);
4629 o_addchr(&ctx.as_string, ch);
4634 if (handle_dollar(&ctx, &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, ';');
4933 /* Make sure we have a controlling tty. If we get started under a job
4934 * aware app (like bash for example), make sure we are now in charge so
4935 * we don't fight over who gets the foreground */
4936 static void setup_job_control(void)
4940 shell_pgrp = getpgrp();
4942 /* If we were ran as 'hush &',
4943 * sleep until we are in the foreground. */
4944 while (tcgetpgrp(G_interactive_fd) != shell_pgrp) {
4945 /* Send TTIN to ourself (should stop us) */
4946 kill(- shell_pgrp, SIGTTIN);
4947 shell_pgrp = getpgrp();
4950 /* We _must_ restore tty pgrp on fatal signals */
4951 set_fatal_signals_to_sigexit();
4953 /* Put ourselves in our own process group. */
4954 bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
4955 /* Grab control of the terminal. */
4956 tcsetpgrp(G_interactive_fd, getpid());
4960 static int set_mode(const char cstate, const char mode)
4962 int state = (cstate == '-' ? 1 : 0);
4964 case 'n': G.fake_mode = state; break;
4965 case 'x': /*G.debug_mode = state;*/ break;
4966 default: return EXIT_FAILURE;
4968 return EXIT_SUCCESS;
4971 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
4972 int hush_main(int argc, char **argv)
4974 static const struct variable const_shell_ver = {
4976 .varstr = (char*)hush_version_str,
4977 .max_len = 1, /* 0 can provoke free(name) */
4985 struct variable *cur_var;
4989 G.root_pid = getpid();
4991 /* Deal with HUSH_VERSION */
4992 G.shell_ver = const_shell_ver; /* copying struct here */
4993 G.top_var = &G.shell_ver;
4994 debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
4995 unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
4996 /* Initialize our shell local variables with the values
4997 * currently living in the environment */
4998 cur_var = G.top_var;
5001 char *value = strchr(*e, '=');
5002 if (value) { /* paranoia */
5003 cur_var->next = xzalloc(sizeof(*cur_var));
5004 cur_var = cur_var->next;
5005 cur_var->varstr = *e;
5006 cur_var->max_len = strlen(*e);
5007 cur_var->flg_export = 1;
5011 debug_printf_env("putenv '%s'\n", hush_version_str);
5012 putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
5014 #if ENABLE_FEATURE_EDITING
5015 G.line_input_state = new_line_input_t(FOR_SHELL);
5017 /* XXX what should these be while sourcing /etc/profile? */
5018 G.global_argc = argc;
5019 G.global_argv = argv;
5020 /* Initialize some more globals to non-zero values */
5022 #if ENABLE_HUSH_INTERACTIVE
5023 if (ENABLE_FEATURE_EDITING)
5024 cmdedit_set_initial_prompt();
5028 if (EXIT_SUCCESS) /* otherwise is already done */
5029 G.last_return_code = EXIT_SUCCESS;
5031 if (argv[0] && argv[0][0] == '-') {
5032 debug_printf("sourcing /etc/profile\n");
5033 input = fopen_for_read("/etc/profile");
5034 if (input != NULL) {
5035 close_on_exec_on(fileno(input));
5036 parse_and_run_file(input);
5042 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
5044 opt = getopt(argc, argv, "c:xins"
5053 G.global_argv = argv + optind;
5054 if (!argv[optind]) {
5055 /* -c 'script' (no params): prevent empty $0 */
5056 *--G.global_argv = argv[0];
5058 } /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
5059 G.global_argc = argc - optind;
5060 parse_and_run_string(optarg);
5063 /* Well, we cannot just declare interactiveness,
5064 * we have to have some stuff (ctty, etc) */
5065 /* G_interactive_fd++; */
5068 /* "-s" means "read from stdin", but this is how we always
5069 * operate, so simply do nothing here. */
5073 G.root_pid = xatoi_u(optarg);
5076 G.last_return_code = xatoi_u(optarg);
5079 G.depth_of_loop = xatoi_u(optarg);
5083 set_local_var(xstrdup(optarg), 0, opt == 'R');
5088 if (!set_mode('-', opt))
5092 fprintf(stderr, "Usage: sh [FILE]...\n"
5093 " or: sh -c command [args]...\n\n");
5101 /* A shell is interactive if the '-i' flag was given, or if all of
5102 * the following conditions are met:
5104 * no arguments remaining or the -s flag given
5105 * standard input is a terminal
5106 * standard output is a terminal
5107 * Refer to Posix.2, the description of the 'sh' utility. */
5108 if (argv[optind] == NULL && input == stdin
5109 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
5111 G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
5112 debug_printf("saved_tty_pgrp=%d\n", G.saved_tty_pgrp);
5113 if (G.saved_tty_pgrp >= 0) {
5114 /* try to dup to high fd#, >= 255 */
5115 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5116 if (G_interactive_fd < 0) {
5117 /* try to dup to any fd */
5118 G_interactive_fd = dup(STDIN_FILENO);
5119 if (G_interactive_fd < 0)
5121 G_interactive_fd = 0;
5123 // TODO: track & disallow any attempts of user
5124 // to (inadvertently) close/redirect it
5127 init_signal_mask(); /* note: ensures SIGCHLD is not masked */
5128 debug_printf("interactive_fd=%d\n", G_interactive_fd);
5129 if (G_interactive_fd) {
5130 fcntl(G_interactive_fd, F_SETFD, FD_CLOEXEC);
5131 /* Looks like they want an interactive shell */
5132 setup_job_control();
5133 /* -1 is special - makes xfuncs longjmp, not exit
5134 * (we reset die_sleep = 0 whereever we [v]fork) */
5136 if (setjmp(die_jmp)) {
5137 /* xfunc has failed! die die die */
5138 hush_exit(xfunc_error_retval);
5141 #elif ENABLE_HUSH_INTERACTIVE
5142 /* no job control compiled, only prompt/line editing */
5143 if (argv[optind] == NULL && input == stdin
5144 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
5146 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5147 if (G_interactive_fd < 0) {
5148 /* try to dup to any fd */
5149 G_interactive_fd = dup(STDIN_FILENO);
5150 if (G_interactive_fd < 0)
5152 G_interactive_fd = 0;
5154 if (G_interactive_fd) {
5155 fcntl(G_interactive_fd, F_SETFD, FD_CLOEXEC);
5158 init_signal_mask(); /* note: ensures SIGCHLD is not masked */
5162 /* POSIX allows shell to re-enable SIGCHLD
5163 * even if it was SIG_IGN on entry */
5164 // G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
5165 signal(SIGCHLD, SIG_DFL); // SIGCHLD_handler);
5167 #if ENABLE_HUSH_INTERACTIVE && !ENABLE_FEATURE_SH_EXTRA_QUIET
5168 if (G_interactive_fd) {
5169 printf("\n\n%s hush - the humble shell v"HUSH_VER_STR"\n", bb_banner);
5170 printf("Enter 'help' for a list of built-in commands.\n\n");
5174 if (argv[optind] == NULL) {
5175 parse_and_run_file(stdin);
5177 debug_printf("\nrunning script '%s'\n", argv[optind]);
5178 G.global_argv = argv + optind;
5179 G.global_argc = argc - optind;
5180 input = xfopen_for_read(argv[optind]);
5181 fcntl(fileno(input), F_SETFD, FD_CLOEXEC);
5182 parse_and_run_file(input);
5187 #if ENABLE_FEATURE_CLEAN_UP
5189 if (G.cwd != bb_msg_unknown)
5191 cur_var = G.top_var->next;
5193 struct variable *tmp = cur_var;
5194 if (!cur_var->max_len)
5195 free(cur_var->varstr);
5196 cur_var = cur_var->next;
5200 hush_exit(G.last_return_code);
5205 int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5206 int lash_main(int argc, char **argv)
5208 //bb_error_msg("lash is deprecated, please use hush instead");
5209 return hush_main(argc, argv);
5217 static int builtin_trap(char **argv)
5224 G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
5227 /* No args: print all trapped. This isn't 100% correct as we should
5228 * be escaping the cmd so that it can be pasted back in ...
5230 for (i = 0; i < NSIG; ++i)
5232 printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
5233 return EXIT_SUCCESS;
5238 /* if first arg is decimal: reset all specified */
5239 sig = bb_strtou(*++argv, NULL, 10);
5245 sig = get_signum(*argv++);
5246 if (sig < 0 || sig >= NSIG) {
5248 /* mimic bash message exactly */
5249 bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
5254 G.traps[sig] = xstrdup(new_cmd);
5256 debug_printf("trap: setting SIG%s (%i) to '%s'",
5257 get_signame(sig), sig, G.traps[sig]);
5259 /* There is no signal for 0 (EXIT) */
5264 sigaddset(&G.blocked_set, sig);
5266 /* there was a trap handler, we are removing it
5267 * (if sig has non-DFL handling,
5268 * we don't need to do anything) */
5269 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
5271 sigdelset(&G.blocked_set, sig);
5273 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5278 /* first arg is "-": reset all specified to default */
5279 /* first arg is "": ignore all specified */
5280 /* everything else: execute first arg upon signal */
5282 bb_error_msg("trap: invalid arguments");
5283 return EXIT_FAILURE;
5285 if (LONE_DASH(*argv))
5293 static int builtin_true(char **argv UNUSED_PARAM)
5298 static int builtin_test(char **argv)
5305 return test_main(argc, argv - argc);
5308 static int builtin_echo(char **argv)
5315 return echo_main(argc, argv - argc);
5318 static int builtin_eval(char **argv)
5320 int rcode = EXIT_SUCCESS;
5323 char *str = expand_strvec_to_string(argv + 1);
5325 * eval "echo Hi; done" ("done" is syntax error):
5326 * "echo Hi" will not execute too.
5328 parse_and_run_string(str);
5330 rcode = G.last_return_code;
5335 static int builtin_cd(char **argv)
5338 if (argv[1] == NULL) {
5339 /* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
5340 * bash says "bash: cd: HOME not set" and does nothing (exitcode 1)
5342 newdir = getenv("HOME") ? : "/";
5345 if (chdir(newdir)) {
5346 printf("cd: %s: %s\n", newdir, strerror(errno));
5347 return EXIT_FAILURE;
5350 return EXIT_SUCCESS;
5353 static int builtin_exec(char **argv)
5355 if (argv[1] == NULL)
5356 return EXIT_SUCCESS; /* bash does this */
5361 // FIXME: if exec fails, bash does NOT exit! We do...
5362 pseudo_exec_argv(&dummy, argv + 1, 0, NULL);
5367 static int builtin_exit(char **argv)
5369 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
5370 //puts("exit"); /* bash does it */
5371 // TODO: warn if we have background jobs: "There are stopped jobs"
5372 // On second consecutive 'exit', exit anyway.
5373 if (argv[1] == NULL)
5374 hush_exit(G.last_return_code);
5375 /* mimic bash: exit 123abc == exit 255 + error msg */
5376 xfunc_error_retval = 255;
5377 /* bash: exit -2 == exit 254, no error msg */
5378 hush_exit(xatoi(argv[1]) & 0xff);
5381 static int builtin_export(char **argv)
5384 char *name = argv[1];
5388 // ash emits: export VAR='VAL'
5389 // bash: declare -x VAR="VAL"
5390 // (both also escape as needed (quotes, $, etc))
5395 return EXIT_SUCCESS;
5398 value = strchr(name, '=');
5400 /* They are exporting something without a =VALUE */
5401 struct variable *var;
5403 var = get_local_var(name);
5405 var->flg_export = 1;
5406 debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
5407 putenv(var->varstr);
5409 /* bash does not return an error when trying to export
5410 * an undefined variable. Do likewise. */
5411 return EXIT_SUCCESS;
5414 set_local_var(xstrdup(name), 1, 0);
5415 return EXIT_SUCCESS;
5419 /* built-in 'fg' and 'bg' handler */
5420 static int builtin_fg_bg(char **argv)
5425 if (!G_interactive_fd)
5426 return EXIT_FAILURE;
5427 /* If they gave us no args, assume they want the last backgrounded task */
5429 for (pi = G.job_list; pi; pi = pi->next) {
5430 if (pi->jobid == G.last_jobid) {
5434 bb_error_msg("%s: no current job", argv[0]);
5435 return EXIT_FAILURE;
5437 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
5438 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
5439 return EXIT_FAILURE;
5441 for (pi = G.job_list; pi; pi = pi->next) {
5442 if (pi->jobid == jobnum) {
5446 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
5447 return EXIT_FAILURE;
5449 // TODO: bash prints a string representation
5450 // of job being foregrounded (like "sleep 1 | cat")
5451 if (argv[0][0] == 'f') {
5452 /* Put the job into the foreground. */
5453 tcsetpgrp(G_interactive_fd, pi->pgrp);
5456 /* Restart the processes in the job */
5457 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
5458 for (i = 0; i < pi->num_cmds; i++) {
5459 debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
5460 pi->cmds[i].is_stopped = 0;
5462 pi->stopped_cmds = 0;
5464 i = kill(- pi->pgrp, SIGCONT);
5466 if (errno == ESRCH) {
5467 delete_finished_bg_job(pi);
5468 return EXIT_SUCCESS;
5470 bb_perror_msg("kill (SIGCONT)");
5473 if (argv[0][0] == 'f') {
5475 return checkjobs_and_fg_shell(pi);
5477 return EXIT_SUCCESS;
5481 #if ENABLE_HUSH_HELP
5482 static int builtin_help(char **argv UNUSED_PARAM)
5484 const struct built_in_command *x;
5487 "Built-in commands:\n"
5488 "------------------\n");
5489 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
5490 printf("%s\t%s\n", x->cmd, x->descr);
5493 return EXIT_SUCCESS;
5498 static int builtin_jobs(char **argv UNUSED_PARAM)
5501 const char *status_string;
5503 for (job = G.job_list; job; job = job->next) {
5504 if (job->alive_cmds == job->stopped_cmds)
5505 status_string = "Stopped";
5507 status_string = "Running";
5509 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
5511 return EXIT_SUCCESS;
5515 static int builtin_pwd(char **argv UNUSED_PARAM)
5518 return EXIT_SUCCESS;
5521 static int builtin_read(char **argv)
5524 const char *name = argv[1] ? argv[1] : "REPLY";
5526 string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
5527 return set_local_var(string, 0, 0);
5530 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
5531 * built-in 'set' handler
5533 * set [-abCefhmnuvx] [-o option] [argument...]
5534 * set [+abCefhmnuvx] [+o option] [argument...]
5535 * set -- [argument...]
5538 * Implementations shall support the options in both their hyphen and
5539 * plus-sign forms. These options can also be specified as options to sh.
5541 * Write out all variables and their values: set
5542 * Set $1, $2, and $3 and set "$#" to 3: set c a b
5543 * Turn on the -x and -v options: set -xv
5544 * Unset all positional parameters: set --
5545 * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
5546 * Set the positional parameters to the expansion of x, even if x expands
5547 * with a leading '-' or '+': set -- $x
5549 * So far, we only support "set -- [argument...]" and some of the short names.
5551 static int builtin_set(char **argv)
5554 char **pp, **g_argv;
5555 char *arg = *++argv;
5559 for (e = G.top_var; e; e = e->next)
5561 return EXIT_SUCCESS;
5565 if (!strcmp(arg, "--")) {
5570 if (arg[0] == '+' || arg[0] == '-') {
5571 for (n = 1; arg[n]; ++n)
5572 if (set_mode(arg[0], arg[n]))
5578 } while ((arg = *++argv) != NULL);
5579 /* Now argv[0] is 1st argument */
5581 /* Only reset global_argv if we didn't process anything */
5583 return EXIT_SUCCESS;
5586 /* NB: G.global_argv[0] ($0) is never freed/changed */
5587 g_argv = G.global_argv;
5588 if (G.global_args_malloced) {
5594 G.global_args_malloced = 1;
5595 pp = xzalloc(sizeof(pp[0]) * 2);
5596 pp[0] = g_argv[0]; /* retain $0 */
5599 /* This realloc's G.global_argv */
5600 G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
5607 return EXIT_SUCCESS;
5609 /* Nothing known, so abort */
5611 bb_error_msg("set: %s: invalid option", arg);
5612 return EXIT_FAILURE;
5615 static int builtin_shift(char **argv)
5621 if (n >= 0 && n < G.global_argc) {
5622 if (G.global_args_malloced) {
5625 free(G.global_argv[m++]);
5628 memmove(&G.global_argv[1], &G.global_argv[n+1],
5629 G.global_argc * sizeof(G.global_argv[0]));
5630 return EXIT_SUCCESS;
5632 return EXIT_FAILURE;
5635 static int builtin_source(char **argv)
5639 if (argv[1] == NULL)
5640 return EXIT_FAILURE;
5642 /* XXX search through $PATH is missing */
5643 input = fopen_for_read(argv[1]);
5645 bb_error_msg("can't open '%s'", argv[1]);
5646 return EXIT_FAILURE;
5648 close_on_exec_on(fileno(input));
5650 /* Now run the file */
5651 /* XXX argv and argc are broken; need to save old G.global_argv
5652 * (pointer only is OK!) on this stack frame,
5653 * set G.global_argv=argv+1, recurse, and restore. */
5654 parse_and_run_file(input);
5656 return G.last_return_code;
5659 static int builtin_umask(char **argv)
5662 const char *arg = argv[1];
5664 new_umask = bb_strtou(arg, NULL, 8);
5666 return EXIT_FAILURE;
5668 new_umask = umask(0);
5669 printf("%.3o\n", (unsigned) new_umask);
5672 return EXIT_SUCCESS;
5675 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
5676 static int builtin_unset(char **argv)
5683 return EXIT_SUCCESS;
5686 if (argv[1][0] == '-') {
5687 switch (argv[1][1]) {
5689 case 'f': if (ENABLE_HUSH_FUNCTIONS) { var = false; break; }
5691 bb_error_msg("unset: %s: invalid option", argv[1]);
5692 return EXIT_FAILURE;
5700 if (unset_local_var(argv[i]))
5703 #if ENABLE_HUSH_FUNCTIONS
5705 unset_local_func(argv[i]);
5711 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
5712 static int builtin_wait(char **argv)
5714 int ret = EXIT_SUCCESS;
5717 if (*++argv == NULL) {
5718 /* Don't care about wait results */
5719 /* Note 1: must wait until there are no more children */
5720 /* Note 2: must be interruptible */
5722 * $ sleep 3 & sleep 6 & wait
5727 * $ sleep 3 & sleep 6 & wait
5731 * ^C <-- after ~4 sec from keyboard
5734 sigaddset(&G.blocked_set, SIGCHLD);
5735 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5738 if (errno == ECHILD)
5740 /* Wait for SIGCHLD or any other signal of interest */
5741 /* sigtimedwait with infinite timeout: */
5742 sig = sigwaitinfo(&G.blocked_set, NULL);
5744 sig = check_and_run_traps(sig);
5745 if (sig && sig != SIGCHLD) { /* see note 2 */
5751 sigdelset(&G.blocked_set, SIGCHLD);
5752 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5756 /* This is probably buggy wrt interruptible-ness */
5758 pid_t pid = bb_strtou(*argv, NULL, 10);
5760 /* mimic bash message */
5761 bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
5762 return EXIT_FAILURE;
5764 if (waitpid(pid, &status, 0) == pid) {
5765 if (WIFSIGNALED(status))
5766 ret = 128 + WTERMSIG(status);
5767 else if (WIFEXITED(status))
5768 ret = WEXITSTATUS(status);
5772 bb_perror_msg("wait %s", *argv);
5781 #if ENABLE_HUSH_LOOPS
5782 static int builtin_break(char **argv)
5784 if (G.depth_of_loop == 0) {
5785 bb_error_msg("%s: only meaningful in a loop", argv[0]);
5786 return EXIT_SUCCESS; /* bash compat */
5788 G.flag_break_continue++; /* BC_BREAK = 1 */
5789 G.depth_break_continue = 1;
5791 G.depth_break_continue = bb_strtou(argv[1], NULL, 10);
5792 if (errno || !G.depth_break_continue || argv[2]) {
5793 bb_error_msg("%s: bad arguments", argv[0]);
5794 G.flag_break_continue = BC_BREAK;
5795 G.depth_break_continue = UINT_MAX;
5798 if (G.depth_of_loop < G.depth_break_continue)
5799 G.depth_break_continue = G.depth_of_loop;
5800 return EXIT_SUCCESS;
5803 static int builtin_continue(char **argv)
5805 G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
5806 return builtin_break(argv);