1 /* vi: set sw=4 ts=4: */
3 * A prototype Bourne shell grammar parser.
4 * Intended to follow the original Thompson and Ritchie
5 * "small and simple is beautiful" philosophy, which
6 * incidentally is a good match to today's BusyBox.
8 * Copyright (C) 2000,2001 Larry Doolittle <larry@doolittle.boa.org>
9 * Copyright (C) 2008,2009 Denys Vlasenko <vda.linux@googlemail.com>
12 * The parser routines proper are all original material, first
13 * written Dec 2000 and Jan 2001 by Larry Doolittle. The
14 * execution engine, the builtins, and much of the underlying
15 * support has been adapted from busybox-0.49pre's lash, which is
16 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
17 * written by Erik Andersen <andersen@codepoet.org>. That, in turn,
18 * is based in part on ladsh.c, by Michael K. Johnson and Erik W.
19 * Troan, which they placed in the public domain. I don't know
20 * how much of the Johnson/Troan code has survived the repeated
24 * o_addchr() derived from similar w_addchar function in glibc-2.2.
25 * setup_redirect(), redirect_opt_num(), and big chunks of main()
26 * and many builtins derived from contributions by Erik Andersen.
27 * Miscellaneous bugfixes from Matt Kraai.
29 * There are two big (and related) architecture differences between
30 * this parser and the lash parser. One is that this version is
31 * actually designed from the ground up to understand nearly all
32 * of the Bourne grammar. The second, consequential change is that
33 * the parser and input reader have been turned inside out. Now,
34 * the parser is in control, and asks for input as needed. The old
35 * way had the input reader in control, and it asked for parsing to
36 * take place as needed. The new way makes it much easier to properly
37 * handle the recursion implicit in the various substitutions, especially
38 * across continuation lines.
40 * POSIX syntax not implemented:
42 * <(list) and >(list) Process Substitution
43 * Here Documents ( << word )
46 * Parameter Expansion for substring processing ${var#word} ${var%word}
48 * Bash stuff (maybe optionally enable?):
49 * &> and >& redirection of stdout+stderr
51 * reserved words: [[ ]] function select
52 * substrings ${var:1:5}
55 * grep for "TODO" and fix (some of them are easy)
56 * change { and } from special chars to reserved words
57 * builtins: return, ulimit
58 * follow IFS rules more precisely, including update semantics
59 * figure out what to do with backslash-newline
60 * continuation lines, both explicit and implicit - done?
62 * ^Z handling (and explain it in comments for mere humans)
63 * separate job control from interactiveness
64 * (testcase: booting with init=/bin/hush does not show prompt (2009-04))
67 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
70 #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */
71 //TODO: pull in some .h and find out whether we have SINGLE_APPLET_MAIN?
72 //#include "applet_tables.h" doesn't work
74 /* #include <dmalloc.h> */
80 #ifdef WANT_TO_TEST_NOMMU
85 # define USE_FOR_NOMMU(...) __VA_ARGS__
86 # define USE_FOR_MMU(...)
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
195 #define DEBUG_CLEAN 0
199 static void debug_print_strings(const char *prefix, char **vv)
201 fprintf(stderr, "%s:\n", prefix);
203 fprintf(stderr, " '%s'\n", *vv++);
206 #define debug_print_strings(prefix, vv) ((void)0)
210 * Leak hunting. Use hush_leaktool.sh for post-processing.
212 #ifdef FOR_HUSH_LEAKTOOL
213 static void *xxmalloc(int lineno, size_t size)
215 void *ptr = xmalloc((size + 0xff) & ~0xff);
216 fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
219 static void *xxrealloc(int lineno, void *ptr, size_t size)
221 ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
222 fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
225 static char *xxstrdup(int lineno, const char *str)
227 char *ptr = xstrdup(str);
228 fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
231 static void xxfree(void *ptr)
233 fdprintf(2, "free %p\n", ptr);
236 #define xmalloc(s) xxmalloc(__LINE__, s)
237 #define xrealloc(p, s) xxrealloc(__LINE__, p, s)
238 #define xstrdup(s) xxstrdup(__LINE__, s)
239 #define free(p) xxfree(p)
243 #define ERR_PTR ((void*)(long)1)
245 static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="BB_VER;
247 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
249 #define SPECIAL_VAR_SYMBOL 3
251 typedef enum redir_type {
253 REDIRECT_OVERWRITE = 2,
259 /* The descrip member of this structure is only used to make
260 * debugging output pretty */
261 static const struct {
263 signed char default_fd;
267 { O_RDONLY, 0, "<" },
268 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
269 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
270 { O_RDONLY, -1, "<<" },
274 typedef enum pipe_style {
281 typedef enum reserved_style {
290 #if ENABLE_HUSH_LOOPS
297 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
302 /* two pseudo-keywords support contrived "case" syntax: */
303 RES_MATCH , /* "word)" */
304 RES_CASEI , /* "this command is inside CASE" */
311 typedef struct o_string {
313 int length; /* position where data is appended */
315 /* Protect newly added chars against globbing
316 * (by prepending \ to *, ?, [, \) */
320 smallint has_empty_slot;
321 smallint o_assignment; /* 0:maybe, 1:yes, 2:no */
324 MAYBE_ASSIGNMENT = 0,
325 DEFINITELY_ASSIGNMENT = 1,
327 WORD_IS_KEYWORD = 3, /* not assigment, but next word may be: "if v=xyz cmd;" */
329 /* Used for initialization: o_string foo = NULL_O_STRING; */
330 #define NULL_O_STRING { NULL }
332 /* I can almost use ordinary FILE*. Is open_memstream() universally
333 * available? Where is it documented? */
334 typedef struct in_str {
336 /* eof_flag=1: last char in ->p is really an EOF */
337 char eof_flag; /* meaningless if ->p == NULL */
339 #if ENABLE_HUSH_INTERACTIVE
341 smallint promptmode; /* 0: PS1, 1: PS2 */
344 int (*get) (struct in_str *);
345 int (*peek) (struct in_str *);
347 #define i_getch(input) ((input)->get(input))
348 #define i_peek(input) ((input)->peek(input))
350 struct redir_struct {
351 struct redir_struct *next;
352 char *rd_filename; /* filename */
353 int fd; /* file descriptor being redirected */
354 int dup; /* -1, or file descriptor being duplicated */
355 smallint /*enum redir_type*/ rd_type;
359 pid_t pid; /* 0 if exited */
360 int assignment_cnt; /* how many argv[i] are assignments? */
361 smallint is_stopped; /* is the command currently running? */
362 smallint grp_type; /* GRP_xxx */
363 struct pipe *group; /* if non-NULL, this "command" is { list },
364 * ( list ), or a compound statement */
366 char *group_as_string;
368 char **argv; /* command name and arguments */
369 struct redir_struct *redirects; /* I/O redirections */
371 /* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
372 * and on execution these are substituted with their values.
373 * Substitution can make _several_ words out of one argv[n]!
374 * Example: argv[0]=='.^C*^C.' here: echo .$*.
375 * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
378 #define GRP_SUBSHELL 1
379 #if ENABLE_HUSH_FUNCTIONS
380 #define GRP_FUNCTION 2
385 int num_cmds; /* total number of commands in job */
386 int alive_cmds; /* number of commands running (not exited) */
387 int stopped_cmds; /* number of commands alive, but stopped */
389 int jobid; /* job number */
390 pid_t pgrp; /* process group ID for the job */
391 char *cmdtext; /* name of job */
393 struct command *cmds; /* array of commands in pipe */
394 smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
395 IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */
396 IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */
399 /* This holds pointers to the various results of parsing */
400 struct parse_context {
401 /* linked list of pipes */
402 struct pipe *list_head;
403 /* last pipe (being constructed right now) */
405 /* last command in pipe (being constructed right now) */
406 struct command *command;
407 /* last redirect in command->redirects list */
408 struct redir_struct *pending_redirect;
414 smallint ctx_inverted; /* "! cmd | cmd" */
416 smallint ctx_dsemicolon; /* ";;" seen */
418 /* bitmask of FLAG_xxx, for figuring out valid reserved words */
420 /* group we are enclosed in:
421 * example: "if pipe1; pipe2; then pipe3; fi"
422 * when we see "if" or "then", we malloc and copy current context,
423 * and make ->stack point to it. then we parse pipeN.
424 * when closing "then" / fi" / whatever is found,
425 * we move list_head into ->stack->command->group,
426 * copy ->stack into current context, and delete ->stack.
427 * (parsing of { list } and ( list ) doesn't use this method)
429 struct parse_context *stack;
433 /* On program start, environ points to initial environment.
434 * putenv adds new pointers into it, unsetenv removes them.
435 * Neither of these (de)allocates the strings.
436 * setenv allocates new strings in malloc space and does putenv,
437 * and thus setenv is unusable (leaky) for shell's purposes */
438 #define setenv(...) setenv_is_leaky_dont_use()
440 struct variable *next;
441 char *varstr; /* points to "name=" portion */
442 int max_len; /* if > 0, name is part of initial env; else name is malloced */
443 smallint flg_export; /* putenv should be done on this var */
444 smallint flg_read_only;
453 /* "Globals" within this file */
454 /* Sorted roughly by size (smaller offsets == smaller code) */
456 #if ENABLE_HUSH_INTERACTIVE
457 /* 'interactive_fd' is a fd# open to ctty, if we have one
458 * _AND_ if we decided to act interactively */
462 #define G_interactive_fd (G.interactive_fd)
464 #define G_interactive_fd 0
466 #if ENABLE_FEATURE_EDITING
467 line_input_t *line_input_state;
473 pid_t saved_tty_pgrp;
475 struct pipe *job_list;
476 struct pipe *toplevel_list;
477 //// smallint ctrl_z_flag;
479 smallint flag_SIGINT;
480 #if ENABLE_HUSH_LOOPS
481 smallint flag_break_continue;
484 /* These four support $?, $#, and $1 */
485 smalluint last_return_code;
486 /* are global_argv and global_argv[1..n] malloced? (note: not [0]) */
487 smalluint global_args_malloced;
488 /* how many non-NULL argv's we have. NB: $# + 1 */
492 char *argv0_for_re_execing;
493 char **argv_from_re_execing;
495 #if ENABLE_HUSH_LOOPS
496 unsigned depth_break_continue;
497 unsigned depth_of_loop;
501 struct variable *top_var; /* = &G.shell_ver (set in main()) */
502 struct variable shell_ver;
503 /* Signal and trap handling */
504 // unsigned count_SIGCHLD;
505 // unsigned handled_SIGCHLD;
506 /* which signals have non-DFL handler (even with no traps set)? */
507 unsigned non_DFL_mask;
508 char **traps; /* char *traps[NSIG] */
509 sigset_t blocked_set;
510 sigset_t inherited_set;
511 char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
512 #if ENABLE_FEATURE_SH_STANDALONE
513 struct nofork_save_area nofork_save;
516 sigjmp_buf toplevel_jb;
519 #define G (*ptr_to_globals)
520 /* Not #defining name to G.name - this quickly gets unwieldy
521 * (too many defines). Also, I actually prefer to see when a variable
522 * is global, thus "G." prefix is a useful hint */
523 #define INIT_G() do { \
524 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
528 /* Function prototypes for builtins */
529 static int builtin_cd(char **argv);
530 static int builtin_echo(char **argv);
531 static int builtin_eval(char **argv);
532 static int builtin_exec(char **argv);
533 static int builtin_exit(char **argv);
534 static int builtin_export(char **argv);
536 static int builtin_fg_bg(char **argv);
537 static int builtin_jobs(char **argv);
540 static int builtin_help(char **argv);
542 static int builtin_pwd(char **argv);
543 static int builtin_read(char **argv);
544 static int builtin_test(char **argv);
545 static int builtin_trap(char **argv);
546 static int builtin_true(char **argv);
547 static int builtin_set(char **argv);
548 static int builtin_shift(char **argv);
549 static int builtin_source(char **argv);
550 static int builtin_umask(char **argv);
551 static int builtin_unset(char **argv);
552 static int builtin_wait(char **argv);
553 #if ENABLE_HUSH_LOOPS
554 static int builtin_break(char **argv);
555 static int builtin_continue(char **argv);
558 /* Table of built-in functions. They can be forked or not, depending on
559 * context: within pipes, they fork. As simple commands, they do not.
560 * When used in non-forking context, they can change global variables
561 * in the parent shell process. If forked, of course they cannot.
562 * For example, 'unset foo | whatever' will parse and run, but foo will
563 * still be set at the end. */
564 struct built_in_command {
566 int (*function)(char **argv);
569 #define BLTIN(cmd, func, help) { cmd, func, help }
571 #define BLTIN(cmd, func, help) { cmd, func }
575 /* For now, echo and test are unconditionally enabled.
576 * Maybe make it configurable? */
577 static const struct built_in_command bltins[] = {
578 BLTIN("." , builtin_source , "Run commands in a file"),
579 BLTIN(":" , builtin_true , "No-op"),
580 BLTIN("[" , builtin_test , "Test condition"),
582 BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
584 #if ENABLE_HUSH_LOOPS
585 BLTIN("break" , builtin_break , "Exit from a loop"),
587 BLTIN("cd" , builtin_cd , "Change directory"),
588 #if ENABLE_HUSH_LOOPS
589 BLTIN("continue", builtin_continue, "Start new loop iteration"),
591 BLTIN("echo" , builtin_echo , "Write to stdout"),
592 BLTIN("eval" , builtin_eval , "Construct and run shell command"),
593 BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
594 BLTIN("exit" , builtin_exit , "Exit"),
595 BLTIN("export" , builtin_export , "Set environment variable"),
597 BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
600 BLTIN("help" , builtin_help , "List shell built-in commands"),
603 BLTIN("jobs" , builtin_jobs , "List active jobs"),
605 BLTIN("pwd" , builtin_pwd , "Print current directory"),
606 BLTIN("read" , builtin_read , "Input environment variable"),
607 // BLTIN("return" , builtin_return , "Return from a function"),
608 BLTIN("set" , builtin_set , "Set/unset shell local variables"),
609 BLTIN("shift" , builtin_shift , "Shift positional parameters"),
610 BLTIN("test" , builtin_test , "Test condition"),
611 BLTIN("trap" , builtin_trap , "Trap signals"),
612 // BLTIN("ulimit" , builtin_return , "Control resource limits"),
613 BLTIN("umask" , builtin_umask , "Set file creation mask"),
614 BLTIN("unset" , builtin_unset , "Unset environment variable"),
615 BLTIN("wait" , builtin_wait , "Wait for process"),
619 static void maybe_die(const char *notice, const char *msg)
621 /* Was using fancy stuff:
622 * (G_interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...)
623 * but it SEGVs. ?! Oh well... explicit temp ptr works around that */
624 void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die;
625 #if ENABLE_HUSH_INTERACTIVE
626 if (G_interactive_fd)
629 fp(msg ? "%s: %s" : notice, notice, msg);
632 #define syntax(msg) maybe_die("syntax error", msg);
634 /* Debug -- trick gcc to expand __LINE__ and convert to string */
635 #define __syntax(msg, line) maybe_die("syntax error hush.c:" # line, msg)
636 #define _syntax(msg, line) __syntax(msg, line)
637 #define syntax(msg) _syntax(msg, __LINE__)
641 static int glob_needed(const char *s)
646 if (*s == '*' || *s == '[' || *s == '?')
653 static int is_assignment(const char *s)
655 if (!s || !(isalpha(*s) || *s == '_'))
658 while (isalnum(*s) || *s == '_')
663 /* Replace each \x with x in place, return ptr past NUL. */
664 static char *unbackslash(char *src)
670 if ((*dst++ = *src++) == '\0')
676 static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
697 v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
698 v[count1 + count2] = NULL;
701 v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
705 static char **add_string_to_strings(char **strings, char *add)
710 return add_strings_to_strings(strings, v, /*dup:*/ 0);
713 static void putenv_all(char **strings)
718 debug_printf_env("putenv '%s'\n", *strings);
723 static char **putenv_all_and_save_old(char **strings)
733 eq = strchr(*strings, '=');
736 v = getenv(*strings);
739 /* v points to VAL in VAR=VAL, go back to VAR */
740 v -= (eq - *strings) + 1;
741 old = add_string_to_strings(old, v);
750 static void free_strings_and_unsetenv(char **strings, int unset)
760 debug_printf_env("unsetenv '%s'\n", *v);
768 static void free_strings(char **strings)
770 free_strings_and_unsetenv(strings, 0);
774 /* Basic theory of signal handling in shell
775 * ========================================
776 * This does not describe what hush does, rather, it is current understanding
777 * what it _should_ do. If it doesn't, it's a bug.
778 * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
780 * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
781 * is finished or backgrounded. It is the same in interactive and
782 * non-interactive shells, and is the same regardless of whether
783 * a user trap handler is installed or a shell special one is in effect.
784 * ^C or ^Z from keyboard seem to execute "at once" because it usually
785 * backgrounds (i.e. stops) or kills all members of currently running
788 * Wait builtin in interruptible by signals for which user trap is set
789 * or by SIGINT in interactive shell.
791 * Trap handlers will execute even within trap handlers. (right?)
793 * User trap handlers are forgotten when subshell ("(cmd)") is entered. [TODO]
795 * If job control is off, backgrounded commands ("cmd &")
796 * have SIGINT, SIGQUIT set to SIG_IGN.
798 * Commands run in command substitution ("`cmd`")
799 * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
801 * Ordinary commands have signals set to SIG_IGN/DFL set as inherited
802 * by the shell from its parent.
804 * Siganls which differ from SIG_DFL action
805 * (note: child (i.e., [v]forked) shell is not an interactive shell):
808 * SIGTERM (interactive): ignore
809 * SIGHUP (interactive):
810 * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
811 * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
812 * (note that ^Z is handled not by trapping SIGTSTP, but by seeing
813 * that all pipe members are stopped) (right?)
814 * SIGINT (interactive): wait for last pipe, ignore the rest
815 * of the command line, show prompt. NB: ^C does not send SIGINT
816 * to interactive shell while shell is waiting for a pipe,
817 * since shell is bg'ed (is not in foreground process group).
818 * (check/expand this)
819 * Example 1: this waits 5 sec, but does not execute ls:
820 * "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
821 * Example 2: this does not wait and does not execute ls:
822 * "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
823 * Example 3: this does not wait 5 sec, but executes ls:
824 * "sleep 5; ls -l" + press ^C
826 * (What happens to signals which are IGN on shell start?)
827 * (What happens with signal mask on shell start?)
829 * Implementation in hush
830 * ======================
831 * We use in-kernel pending signal mask to determine which signals were sent.
832 * We block all signals which we don't want to take action immediately,
833 * i.e. we block all signals which need to have special handling as described
834 * above, and all signals which have traps set.
835 * After each pipe execution, we extract any pending signals via sigtimedwait()
838 * unsigned non_DFL_mask: a mask of such "special" signals
839 * sigset_t blocked_set: current blocked signal set
842 * clear bit in blocked_set unless it is also in non_DFL_mask
843 * "trap 'cmd' SIGxxx":
844 * set bit in blocked_set (even if 'cmd' is '')
845 * after [v]fork, if we plan to be a shell:
846 * nothing for {} child shell (say, "true | { true; true; } | true")
847 * unset all traps if () shell. [TODO]
848 * after [v]fork, if we plan to exec:
849 * POSIX says pending signal mask is cleared in child - no need to clear it.
850 * Restore blocked signal set to one inherited by shell just prior to exec.
852 * Note: as a result, we do not use signal handlers much. The only uses
853 * are to count SIGCHLDs [disabled - bug somewhere, + bloat]
854 * and to restore tty pgrp on signal-induced exit.
857 //static void SIGCHLD_handler(int sig UNUSED_PARAM)
859 // G.count_SIGCHLD++;
862 static int check_and_run_traps(int sig)
864 static const struct timespec zero_timespec = { 0, 0 };
865 smalluint save_rcode;
871 sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec);
876 if (G.traps && G.traps[sig]) {
877 if (G.traps[sig][0]) {
878 /* We have user-defined handler */
879 char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL };
880 save_rcode = G.last_return_code;
883 G.last_return_code = save_rcode;
884 } /* else: "" trap, ignoring signal */
887 /* not a trap: special action */
890 // G.count_SIGCHLD++;
899 default: /* ignored: */
900 /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
908 /* Restores tty foreground process group, and exits.
909 * May be called as signal handler for fatal signal
910 * (will faithfully resend signal to itself, producing correct exit state)
911 * or called directly with -EXITCODE.
912 * We also call it if xfunc is exiting. */
913 static void sigexit(int sig) NORETURN;
914 static void sigexit(int sig)
916 /* Disable all signals: job control, SIGPIPE, etc. */
917 sigprocmask_allsigs(SIG_BLOCK);
919 /* Careful: we can end up here after [v]fork. Do not restore
920 * tty pgrp then, only top-level shell process does that */
921 if (G_interactive_fd && getpid() == G.root_pid)
922 tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
924 /* Not a signal, just exit */
928 kill_myself_with_sig(sig); /* does not return */
932 /* Restores tty foreground process group, and exits. */
933 static void hush_exit(int exitcode) NORETURN;
934 static void hush_exit(int exitcode)
936 if (G.traps && G.traps[0] && G.traps[0][0]) {
937 char *argv[] = { NULL, xstrdup(G.traps[0]), NULL };
938 //TODO: do we need to prevent recursion?
944 fflush(NULL); /* flush all streams */
945 sigexit(- (exitcode & 0xff));
952 static const char *set_cwd(void)
954 /* xrealloc_getcwd_or_warn(arg) calls free(arg),
955 * we must not try to free(bb_msg_unknown) */
956 if (G.cwd == bb_msg_unknown)
958 G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
960 G.cwd = bb_msg_unknown;
965 /* Get/check local shell variables */
966 static struct variable *get_local_var(const char *name)
968 struct variable *cur;
974 for (cur = G.top_var; cur; cur = cur->next) {
975 if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
981 static const char *get_local_var_value(const char *src)
983 struct variable *var = get_local_var(src);
985 return strchr(var->varstr, '=') + 1;
989 /* str holds "NAME=VAL" and is expected to be malloced.
990 * We take ownership of it.
994 * -1: if NAME is set, leave export status alone
995 * if NAME is not set, do not export
996 * flg_read_only is set only when we handle -R var=val
999 #define set_local_var(str, flg_export, flg_read_only) \
1000 set_local_var(str, flg_export)
1002 static int set_local_var(char *str, int flg_export, int flg_read_only)
1004 struct variable *cur;
1008 value = strchr(str, '=');
1009 if (!value) { /* not expected to ever happen? */
1014 name_len = value - str + 1; /* including '=' */
1015 cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
1017 if (strncmp(cur->varstr, str, name_len) != 0) {
1019 /* Bail out. Note that now cur points
1020 * to last var in linked list */
1026 /* We found an existing var with this name */
1028 if (cur->flg_read_only) {
1032 bb_error_msg("%s: readonly variable", str);
1036 debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
1037 unsetenv(str); /* just in case */
1039 if (strcmp(cur->varstr, str) == 0) {
1044 if (cur->max_len >= strlen(str)) {
1045 /* This one is from startup env, reuse space */
1046 strcpy(cur->varstr, str);
1049 /* max_len == 0 signifies "malloced" var, which we can
1050 * (and has to) free */
1054 goto set_str_and_exp;
1057 /* Not found - create next variable struct */
1058 cur->next = xzalloc(sizeof(*cur));
1064 cur->flg_read_only = flg_read_only;
1067 if (flg_export == 1)
1068 cur->flg_export = 1;
1069 if (cur->flg_export) {
1070 debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
1071 return putenv(cur->varstr);
1076 static int unset_local_var(const char *name)
1078 struct variable *cur;
1079 struct variable *prev = prev; /* for gcc */
1083 return EXIT_SUCCESS;
1084 name_len = strlen(name);
1087 if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
1088 if (cur->flg_read_only) {
1089 bb_error_msg("%s: readonly variable", name);
1090 return EXIT_FAILURE;
1092 /* prev is ok to use here because 1st variable, HUSH_VERSION,
1093 * is ro, and we cannot reach this code on the 1st pass */
1094 prev->next = cur->next;
1095 debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
1096 bb_unsetenv(cur->varstr);
1100 return EXIT_SUCCESS;
1105 return EXIT_SUCCESS;
1108 #if ENABLE_SH_MATH_SUPPORT
1109 #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c)))
1110 #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c)))
1111 static char *endofname(const char *name)
1119 if (!is_in_name(*p))
1125 static void arith_set_local_var(const char *name, const char *val, int flags)
1127 /* arith code doesnt malloc space, so do it for it */
1128 char *var = xasprintf("%s=%s", name, val);
1129 set_local_var(var, flags, 0);
1137 static int static_get(struct in_str *i)
1146 static int static_peek(struct in_str *i)
1151 #if ENABLE_HUSH_INTERACTIVE
1153 static void cmdedit_set_initial_prompt(void)
1155 if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1156 G.PS1 = getenv("PS1");
1163 static const char* setup_prompt_string(int promptmode)
1165 const char *prompt_str;
1166 debug_printf("setup_prompt_string %d ", promptmode);
1167 if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1168 /* Set up the prompt */
1169 if (promptmode == 0) { /* PS1 */
1171 G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#');
1176 prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
1177 debug_printf("result '%s'\n", prompt_str);
1181 static void get_user_input(struct in_str *i)
1184 const char *prompt_str;
1186 prompt_str = setup_prompt_string(i->promptmode);
1187 #if ENABLE_FEATURE_EDITING
1188 /* Enable command line editing only while a command line
1189 * is actually being read */
1192 /* buglet: SIGINT will not make new prompt to appear _at once_,
1193 * only after <Enter>. (^C will work) */
1194 r = read_line_input(prompt_str, G.user_input_buf, BUFSIZ-1, G.line_input_state);
1195 /* catch *SIGINT* etc (^C is handled by read_line_input) */
1196 check_and_run_traps(0);
1197 } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */
1198 i->eof_flag = (r < 0);
1199 if (i->eof_flag) { /* EOF/error detected */
1200 G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
1201 G.user_input_buf[1] = '\0';
1206 fputs(prompt_str, stdout);
1208 G.user_input_buf[0] = r = fgetc(i->file);
1209 /*G.user_input_buf[1] = '\0'; - already is and never changed */
1210 //do we need check_and_run_traps(0)? (maybe only if stdin)
1211 } while (G.flag_SIGINT);
1212 i->eof_flag = (r == EOF);
1214 i->p = G.user_input_buf;
1217 #endif /* INTERACTIVE */
1219 /* This is the magic location that prints prompts
1220 * and gets data back from the user */
1221 static int file_get(struct in_str *i)
1225 /* If there is data waiting, eat it up */
1226 if (i->p && *i->p) {
1227 #if ENABLE_HUSH_INTERACTIVE
1231 if (i->eof_flag && !*i->p)
1233 /* note: ch is never NUL */
1235 /* need to double check i->file because we might be doing something
1236 * more complicated by now, like sourcing or substituting. */
1237 #if ENABLE_HUSH_INTERACTIVE
1238 if (G_interactive_fd && i->promptme && i->file == stdin) {
1241 } while (!*i->p); /* need non-empty line */
1242 i->promptmode = 1; /* PS2 */
1247 do ch = fgetc(i->file); while (ch == '\0');
1249 debug_printf("file_get: got '%c' %d\n", ch, ch);
1250 #if ENABLE_HUSH_INTERACTIVE
1257 /* All callers guarantee this routine will never
1258 * be used right after a newline, so prompting is not needed.
1260 static int file_peek(struct in_str *i)
1263 if (i->p && *i->p) {
1264 if (i->eof_flag && !i->p[1])
1267 /* note: ch is never NUL */
1269 do ch = fgetc(i->file); while (ch == '\0');
1270 i->eof_flag = (ch == EOF);
1271 i->peek_buf[0] = ch;
1272 i->peek_buf[1] = '\0';
1274 debug_printf("file_peek: got '%c' %d\n", ch, ch);
1278 static void setup_file_in_str(struct in_str *i, FILE *f)
1280 i->peek = file_peek;
1282 #if ENABLE_HUSH_INTERACTIVE
1284 i->promptmode = 0; /* PS1 */
1290 static void setup_string_in_str(struct in_str *i, const char *s)
1292 i->peek = static_peek;
1293 i->get = static_get;
1294 #if ENABLE_HUSH_INTERACTIVE
1296 i->promptmode = 0; /* PS1 */
1306 #define B_CHUNK (32 * sizeof(char*))
1308 static void o_reset(o_string *o)
1316 static void o_free(o_string *o)
1319 memset(o, 0, sizeof(*o));
1322 static ALWAYS_INLINE void o_free_unsafe(o_string *o)
1327 static void o_grow_by(o_string *o, int len)
1329 if (o->length + len > o->maxlen) {
1330 o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
1331 o->data = xrealloc(o->data, 1 + o->maxlen);
1335 static void o_addchr(o_string *o, int ch)
1337 debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
1339 o->data[o->length] = ch;
1341 o->data[o->length] = '\0';
1344 static void o_addblock(o_string *o, const char *str, int len)
1347 memcpy(&o->data[o->length], str, len);
1349 o->data[o->length] = '\0';
1353 static void o_addstr(o_string *o, const char *str)
1355 o_addblock(o, str, strlen(str));
1359 static void o_addstr_with_NUL(o_string *o, const char *str)
1361 o_addblock(o, str, strlen(str) + 1);
1364 static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
1369 && (*str != '*' && *str != '?' && *str != '[')
1377 /* My analysis of quoting semantics tells me that state information
1378 * is associated with a destination, not a source.
1380 static void o_addqchr(o_string *o, int ch)
1383 char *found = strchr("*?[\\", ch);
1388 o->data[o->length] = '\\';
1391 o->data[o->length] = ch;
1393 o->data[o->length] = '\0';
1396 static void o_addQchr(o_string *o, int ch)
1399 if (o->o_escape && strchr("*?[\\", ch)) {
1401 o->data[o->length] = '\\';
1405 o->data[o->length] = ch;
1407 o->data[o->length] = '\0';
1410 static void o_addQstr(o_string *o, const char *str, int len)
1413 o_addblock(o, str, len);
1419 int ordinary_cnt = strcspn(str, "*?[\\");
1420 if (ordinary_cnt > len) /* paranoia */
1422 o_addblock(o, str, ordinary_cnt);
1423 if (ordinary_cnt == len)
1425 str += ordinary_cnt;
1426 len -= ordinary_cnt + 1; /* we are processing + 1 char below */
1430 if (ch) { /* it is necessarily one of "*?[\\" */
1432 o->data[o->length] = '\\';
1436 o->data[o->length] = ch;
1438 o->data[o->length] = '\0';
1442 /* A special kind of o_string for $VAR and `cmd` expansion.
1443 * It contains char* list[] at the beginning, which is grown in 16 element
1444 * increments. Actual string data starts at the next multiple of 16 * (char*).
1445 * list[i] contains an INDEX (int!) into this string data.
1446 * It means that if list[] needs to grow, data needs to be moved higher up
1447 * but list[i]'s need not be modified.
1448 * NB: remembering how many list[i]'s you have there is crucial.
1449 * o_finalize_list() operation post-processes this structure - calculates
1450 * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
1452 #if DEBUG_EXPAND || DEBUG_GLOB
1453 static void debug_print_list(const char *prefix, o_string *o, int n)
1455 char **list = (char**)o->data;
1456 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1458 fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n",
1459 prefix, list, n, string_start, o->length, o->maxlen);
1461 fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i],
1462 o->data + (int)list[i] + string_start,
1463 o->data + (int)list[i] + string_start);
1467 const char *p = o->data + (int)list[n - 1] + string_start;
1468 fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
1472 #define debug_print_list(prefix, o, n) ((void)0)
1475 /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
1476 * in list[n] so that it points past last stored byte so far.
1477 * It returns n+1. */
1478 static int o_save_ptr_helper(o_string *o, int n)
1480 char **list = (char**)o->data;
1484 if (!o->has_empty_slot) {
1485 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1486 string_len = o->length - string_start;
1487 if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
1488 debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
1489 /* list[n] points to string_start, make space for 16 more pointers */
1490 o->maxlen += 0x10 * sizeof(list[0]);
1491 o->data = xrealloc(o->data, o->maxlen + 1);
1492 list = (char**)o->data;
1493 memmove(list + n + 0x10, list + n, string_len);
1494 o->length += 0x10 * sizeof(list[0]);
1496 debug_printf_list("list[%d]=%d string_start=%d\n",
1497 n, string_len, string_start);
1500 /* We have empty slot at list[n], reuse without growth */
1501 string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
1502 string_len = o->length - string_start;
1503 debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n",
1504 n, string_len, string_start);
1505 o->has_empty_slot = 0;
1507 list[n] = (char*)(ptrdiff_t)string_len;
1511 /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
1512 static int o_get_last_ptr(o_string *o, int n)
1514 char **list = (char**)o->data;
1515 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1517 return ((int)(ptrdiff_t)list[n-1]) + string_start;
1520 /* o_glob performs globbing on last list[], saving each result
1521 * as a new list[]. */
1522 static int o_glob(o_string *o, int n)
1528 debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
1530 return o_save_ptr_helper(o, n);
1531 pattern = o->data + o_get_last_ptr(o, n);
1532 debug_printf_glob("glob pattern '%s'\n", pattern);
1533 if (!glob_needed(pattern)) {
1535 o->length = unbackslash(pattern) - o->data;
1536 debug_printf_glob("glob pattern '%s' is literal\n", pattern);
1537 return o_save_ptr_helper(o, n);
1540 memset(&globdata, 0, sizeof(globdata));
1541 gr = glob(pattern, 0, NULL, &globdata);
1542 debug_printf_glob("glob('%s'):%d\n", pattern, gr);
1543 if (gr == GLOB_NOSPACE)
1544 bb_error_msg_and_die("out of memory during glob");
1545 if (gr == GLOB_NOMATCH) {
1546 globfree(&globdata);
1549 if (gr != 0) { /* GLOB_ABORTED ? */
1550 //TODO: testcase for bad glob pattern behavior
1551 bb_error_msg("glob(3) error %d on '%s'", gr, pattern);
1553 if (globdata.gl_pathv && globdata.gl_pathv[0]) {
1554 char **argv = globdata.gl_pathv;
1555 o->length = pattern - o->data; /* "forget" pattern */
1557 o_addstr_with_NUL(o, *argv);
1558 n = o_save_ptr_helper(o, n);
1564 globfree(&globdata);
1566 debug_print_list("o_glob returning", o, n);
1570 /* If o->o_glob == 1, glob the string so far remembered.
1571 * Otherwise, just finish current list[] and start new */
1572 static int o_save_ptr(o_string *o, int n)
1574 if (o->o_glob) { /* if globbing is requested */
1575 /* If o->has_empty_slot, list[n] was already globbed
1576 * (if it was requested back then when it was filled)
1577 * so don't do that again! */
1578 if (!o->has_empty_slot)
1579 return o_glob(o, n); /* o_save_ptr_helper is inside */
1581 return o_save_ptr_helper(o, n);
1584 /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
1585 static char **o_finalize_list(o_string *o, int n)
1590 n = o_save_ptr(o, n); /* force growth for list[n] if necessary */
1592 debug_print_list("finalized", o, n);
1593 debug_printf_expand("finalized n:%d\n", n);
1594 list = (char**)o->data;
1595 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1599 list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start;
1605 /* Expansion can recurse */
1606 #if ENABLE_HUSH_TICK
1607 static int process_command_subs(o_string *dest, const char *s);
1609 static char *expand_string_to_string(const char *str);
1611 #define parse_stream_dquoted(as_string, dest, input, dquote_end) \
1612 parse_stream_dquoted(dest, input, dquote_end)
1614 static int parse_stream_dquoted(o_string *as_string,
1616 struct in_str *input,
1619 /* expand_strvec_to_strvec() takes a list of strings, expands
1620 * all variable references within and returns a pointer to
1621 * a list of expanded strings, possibly with larger number
1622 * of strings. (Think VAR="a b"; echo $VAR).
1623 * This new list is allocated as a single malloc block.
1624 * NULL-terminated list of char* pointers is at the beginning of it,
1625 * followed by strings themself.
1626 * Caller can deallocate entire list by single free(list). */
1628 /* Store given string, finalizing the word and starting new one whenever
1629 * we encounter IFS char(s). This is used for expanding variable values.
1630 * End-of-string does NOT finalize word: think about 'echo -$VAR-' */
1631 static int expand_on_ifs(o_string *output, int n, const char *str)
1634 int word_len = strcspn(str, G.ifs);
1636 if (output->o_escape || !output->o_glob)
1637 o_addQstr(output, str, word_len);
1638 else /* protect backslashes against globbing up :) */
1639 o_addblock_duplicate_backslash(output, str, word_len);
1642 if (!*str) /* EOL - do not finalize word */
1644 o_addchr(output, '\0');
1645 debug_print_list("expand_on_ifs", output, n);
1646 n = o_save_ptr(output, n);
1647 str += strspn(str, G.ifs); /* skip ifs chars */
1649 debug_print_list("expand_on_ifs[1]", output, n);
1653 /* Expand all variable references in given string, adding words to list[]
1654 * at n, n+1,... positions. Return updated n (so that list[n] is next one
1655 * to be filled). This routine is extremely tricky: has to deal with
1656 * variables/parameters with whitespace, $* and $@, and constructs like
1657 * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
1658 static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
1660 /* or_mask is either 0 (normal case) or 0x80
1661 * (expansion of right-hand side of assignment == 1-element expand.
1662 * It will also do no globbing, and thus we must not backslash-quote!) */
1664 char first_ch, ored_ch;
1671 debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
1672 debug_print_list("expand_vars_to_list", output, n);
1673 n = o_save_ptr(output, n);
1674 debug_print_list("expand_vars_to_list[0]", output, n);
1676 while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
1677 #if ENABLE_HUSH_TICK
1678 o_string subst_result = NULL_O_STRING;
1680 #if ENABLE_SH_MATH_SUPPORT
1681 char arith_buf[sizeof(arith_t)*3 + 2];
1683 o_addblock(output, arg, p - arg);
1684 debug_print_list("expand_vars_to_list[1]", output, n);
1686 p = strchr(p, SPECIAL_VAR_SYMBOL);
1688 first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
1689 /* "$@" is special. Even if quoted, it can still
1690 * expand to nothing (not even an empty string) */
1691 if ((first_ch & 0x7f) != '@')
1692 ored_ch |= first_ch;
1695 switch (first_ch & 0x7f) {
1696 /* Highest bit in first_ch indicates that var is double-quoted */
1698 val = utoa(G.root_pid);
1700 case '!': /* bg pid */
1701 val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)"";
1703 case '?': /* exitcode */
1704 val = utoa(G.last_return_code);
1706 case '#': /* argc */
1707 if (arg[1] != SPECIAL_VAR_SYMBOL)
1708 /* actually, it's a ${#var} */
1710 val = utoa(G.global_argc ? G.global_argc-1 : 0);
1715 if (!G.global_argv[i])
1717 ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
1718 if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
1719 smallint sv = output->o_escape;
1720 /* unquoted var's contents should be globbed, so don't escape */
1721 output->o_escape = 0;
1722 while (G.global_argv[i]) {
1723 n = expand_on_ifs(output, n, G.global_argv[i]);
1724 debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
1725 if (G.global_argv[i++][0] && G.global_argv[i]) {
1726 /* this argv[] is not empty and not last:
1727 * put terminating NUL, start new word */
1728 o_addchr(output, '\0');
1729 debug_print_list("expand_vars_to_list[2]", output, n);
1730 n = o_save_ptr(output, n);
1731 debug_print_list("expand_vars_to_list[3]", output, n);
1734 output->o_escape = sv;
1736 /* If or_mask is nonzero, we handle assignment 'a=....$@.....'
1737 * and in this case should treat it like '$*' - see 'else...' below */
1738 if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */
1740 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1741 if (++i >= G.global_argc)
1743 o_addchr(output, '\0');
1744 debug_print_list("expand_vars_to_list[4]", output, n);
1745 n = o_save_ptr(output, n);
1747 } else { /* quoted $*: add as one word */
1749 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1750 if (!G.global_argv[++i])
1753 o_addchr(output, G.ifs[0]);
1757 case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
1758 /* "Empty variable", used to make "" etc to not disappear */
1762 #if ENABLE_HUSH_TICK
1763 case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
1766 //TODO: can we just stuff it into "output" directly?
1767 debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
1768 process_command_subs(&subst_result, arg);
1769 debug_printf_subst("SUBST RES '%s'\n", subst_result.data);
1770 val = subst_result.data;
1773 #if ENABLE_SH_MATH_SUPPORT
1774 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
1775 arith_eval_hooks_t hooks;
1780 arg++; /* skip '+' */
1781 *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
1782 debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
1784 /* Optional: skip expansion if expr is simple ("a + 3", "i++" etc) */
1786 if (strchr(arg, '$') != NULL
1787 #if ENABLE_HUSH_TICK
1788 || strchr(arg, '`') != NULL
1791 /* We need to expand. Example:
1792 * echo $(($a + `echo 1`)) $((1 + $((2)) ))
1794 struct in_str input;
1795 o_string dest = NULL_O_STRING;
1797 setup_string_in_str(&input, arg);
1798 parse_stream_dquoted(NULL, &dest, &input, EOF);
1799 //bb_error_msg("'%s' -> '%s'", arg, dest.data);
1800 exp_str = expand_string_to_string(dest.data);
1801 //bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
1804 hooks.lookupvar = get_local_var_value;
1805 hooks.setvar = arith_set_local_var;
1806 hooks.endofname = endofname;
1807 res = arith(exp_str ? exp_str : arg, &errcode, &hooks);
1812 case -3: maybe_die("arith", "exponent less than 0"); break;
1813 case -2: maybe_die("arith", "divide by zero"); break;
1814 case -5: maybe_die("arith", "expression recursion loop detected"); break;
1815 default: maybe_die("arith", "syntax error"); break;
1818 debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
1819 sprintf(arith_buf, arith_t_fmt, res);
1824 default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
1826 bool exp_len = false;
1827 bool exp_null = false;
1829 char exp_save = exp_save; /* for compiler */
1830 char exp_op = exp_op; /* for compiler */
1831 char *exp_word = exp_word; /* for compiler */
1835 arg[0] = first_ch & 0x7f;
1837 /* prepare for expansions */
1838 if (var[0] == '#') {
1839 /* handle length expansion ${#var} */
1843 /* maybe handle parameter expansion */
1844 exp_off = strcspn(var, ":-=+?");
1848 exp_save = var[exp_off];
1849 exp_null = exp_save == ':';
1850 exp_word = var + exp_off;
1851 if (exp_null) ++exp_word;
1852 exp_op = *exp_word++;
1853 var[exp_off] = '\0';
1857 /* lookup the variable in question */
1858 if (isdigit(var[0])) {
1859 /* handle_dollar() should have vetted var for us */
1861 if (i < G.global_argc)
1862 val = G.global_argv[i];
1863 /* else val remains NULL: $N with too big N */
1865 val = get_local_var_value(var);
1867 /* handle any expansions */
1869 debug_printf_expand("expand: length of '%s' = ", val);
1870 val = utoa(val ? strlen(val) : 0);
1871 debug_printf_expand("%s\n", val);
1872 } else if (exp_off) {
1873 /* we need to do an expansion */
1874 int exp_test = (!val || (exp_null && !val[0]));
1876 exp_test = !exp_test;
1877 debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
1878 exp_null ? "true" : "false", exp_test);
1881 maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
1885 if (exp_op == '=') {
1886 if (isdigit(var[0]) || var[0] == '#') {
1887 maybe_die(var, "special vars cannot assign in this way");
1890 char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
1891 sprintf(new_var, "%s=%s", var, val);
1892 set_local_var(new_var, -1, 0);
1896 var[exp_off] = exp_save;
1900 #if ENABLE_HUSH_TICK
1903 if (!(first_ch & 0x80)) { /* unquoted $VAR */
1904 debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape);
1906 /* unquoted var's contents should be globbed, so don't escape */
1907 smallint sv = output->o_escape;
1908 output->o_escape = 0;
1909 n = expand_on_ifs(output, n, val);
1911 output->o_escape = sv;
1913 } else { /* quoted $VAR, val will be appended below */
1914 debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape);
1917 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
1919 o_addQstr(output, val, strlen(val));
1921 /* Do the check to avoid writing to a const string */
1922 if (*p != SPECIAL_VAR_SYMBOL)
1923 *p = SPECIAL_VAR_SYMBOL;
1925 #if ENABLE_HUSH_TICK
1926 o_free(&subst_result);
1929 } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
1932 debug_print_list("expand_vars_to_list[a]", output, n);
1933 /* this part is literal, and it was already pre-quoted
1934 * if needed (much earlier), do not use o_addQstr here! */
1935 o_addstr_with_NUL(output, arg);
1936 debug_print_list("expand_vars_to_list[b]", output, n);
1937 } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
1938 && !(ored_ch & 0x80) /* and all vars were not quoted. */
1941 /* allow to reuse list[n] later without re-growth */
1942 output->has_empty_slot = 1;
1944 o_addchr(output, '\0');
1949 static char **expand_variables(char **argv, int or_mask)
1954 o_string output = NULL_O_STRING;
1956 if (or_mask & 0x100) {
1957 output.o_escape = 1; /* protect against globbing for "$var" */
1958 /* (unquoted $var will temporarily switch it off) */
1965 n = expand_vars_to_list(&output, n, *v, (char)or_mask);
1968 debug_print_list("expand_variables", &output, n);
1970 /* output.data (malloced in one block) gets returned in "list" */
1971 list = o_finalize_list(&output, n);
1972 debug_print_strings("expand_variables[1]", list);
1976 static char **expand_strvec_to_strvec(char **argv)
1978 return expand_variables(argv, 0x100);
1981 /* Used for expansion of right hand of assignments */
1982 /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs
1984 static char *expand_string_to_string(const char *str)
1986 char *argv[2], **list;
1988 argv[0] = (char*)str;
1990 list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */
1992 if (!list[0] || list[1])
1993 bb_error_msg_and_die("BUG in varexp2");
1994 /* actually, just move string 2*sizeof(char*) bytes back */
1995 overlapping_strcpy((char*)list, list[0]);
1996 debug_printf_expand("string_to_string='%s'\n", (char*)list);
2000 /* Used for "eval" builtin */
2001 static char* expand_strvec_to_string(char **argv)
2005 list = expand_variables(argv, 0x80);
2006 /* Convert all NULs to spaces */
2011 if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
2012 bb_error_msg_and_die("BUG in varexp3");
2013 list[n][-1] = ' '; /* TODO: or to G.ifs[0]? */
2017 overlapping_strcpy((char*)list, list[0]);
2018 debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
2022 static char **expand_assignments(char **argv, int count)
2026 /* Expand assignments into one string each */
2027 for (i = 0; i < count; i++) {
2028 p = add_string_to_strings(p, expand_string_to_string(argv[i]));
2034 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
2035 * and stderr if they are redirected. */
2036 static int setup_redirects(struct command *prog, int squirrel[])
2039 struct redir_struct *redir;
2041 for (redir = prog->redirects; redir; redir = redir->next) {
2042 if (redir->dup == -1 && redir->rd_filename == NULL) {
2043 /* something went wrong in the parse. Pretend it didn't happen */
2046 if (redir->dup == -1) {
2048 mode = redir_table[redir->rd_type].mode;
2049 //TODO: check redir for names like '\\'
2050 p = expand_string_to_string(redir->rd_filename);
2051 openfd = open_or_warn(p, mode);
2054 /* this could get lost if stderr has been redirected, but
2055 bash and ash both lose it as well (though zsh doesn't!) */
2059 openfd = redir->dup;
2062 if (openfd != redir->fd) {
2063 if (squirrel && redir->fd < 3) {
2064 squirrel[redir->fd] = dup(redir->fd);
2067 //close(openfd); // close(-3) ??!
2069 dup2(openfd, redir->fd);
2070 if (redir->dup == -1)
2078 static void restore_redirects(int squirrel[])
2081 for (i = 0; i < 3; i++) {
2084 /* We simply die on error */
2092 #define free_pipe_list(head, indent) free_pipe_list(head)
2093 #define free_pipe(pi, indent) free_pipe(pi)
2095 static void free_pipe_list(struct pipe *head, int indent);
2097 /* Return code is the exit status of the pipe */
2098 static void free_pipe(struct pipe *pi, int indent)
2101 struct command *command;
2102 struct redir_struct *r, *rnext;
2105 if (pi->stopped_cmds > 0) /* why? */
2107 debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
2108 for (i = 0; i < pi->num_cmds; i++) {
2109 command = &pi->cmds[i];
2110 debug_printf_clean("%s command %d:\n", indenter(indent), i);
2111 if (command->argv) {
2112 for (a = 0, p = command->argv; *p; a++, p++) {
2113 debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p);
2115 free_strings(command->argv);
2116 command->argv = NULL;
2118 /* not "else if": on syntax error, we may have both! */
2119 if (command->group) {
2120 debug_printf_clean("%s begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
2121 free_pipe_list(command->group, indent+3);
2122 debug_printf_clean("%s end group\n", indenter(indent));
2123 command->group = NULL;
2126 free(command->group_as_string);
2127 command->group_as_string = NULL;
2129 for (r = command->redirects; r; r = rnext) {
2130 debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->rd_type].descrip);
2132 /* guard against the case >$FOO, where foo is unset or blank */
2133 if (r->rd_filename) {
2134 debug_printf_clean(" %s\n", r->rd_filename);
2135 free(r->rd_filename);
2136 r->rd_filename = NULL;
2139 debug_printf_clean("&%d\n", r->dup);
2144 command->redirects = NULL;
2146 free(pi->cmds); /* children are an array, they get freed all at once */
2154 static void free_pipe_list(struct pipe *head, int indent)
2156 struct pipe *pi, *next;
2158 for (pi = head; pi; pi = next) {
2160 debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word);
2162 free_pipe(pi, indent);
2163 debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup);
2165 /*pi->next = NULL;*/
2172 typedef struct nommu_save_t {
2178 #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
2179 pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
2180 #define pseudo_exec(nommu_save, command, argv_expanded) \
2181 pseudo_exec(command, argv_expanded)
2184 /* Called after [v]fork() in run_pipe(), or from builtin_exec().
2186 * XXX no exit() here. If you don't exec, use _exit instead.
2187 * The at_exit handlers apparently confuse the calling process,
2188 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
2189 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2190 char **argv, int assignment_cnt,
2191 char **argv_expanded) NORETURN;
2192 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2193 char **argv, int assignment_cnt,
2194 char **argv_expanded)
2198 /* Case when we are here: ... | var=val | ... */
2199 if (!argv[assignment_cnt])
2200 _exit(EXIT_SUCCESS);
2202 new_env = expand_assignments(argv, assignment_cnt);
2204 putenv_all(new_env);
2205 free(new_env); /* optional */
2207 nommu_save->new_env = new_env;
2208 nommu_save->old_env = putenv_all_and_save_old(new_env);
2210 if (argv_expanded) {
2211 argv = argv_expanded;
2213 argv = expand_strvec_to_strvec(argv + assignment_cnt);
2215 nommu_save->argv = argv;
2219 /* On NOMMU, we must never block!
2220 * Example: { sleep 99999 | read line } & echo Ok
2221 * read builtin will block on read syscall, leaving parent blocked
2222 * in vfork. Therefore we can't do this:
2225 /* Check if the command matches any of the builtins.
2226 * Depending on context, this might be redundant. But it's
2227 * easier to waste a few CPU cycles than it is to figure out
2228 * if this is one of those cases.
2232 const struct built_in_command *x;
2233 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2234 if (strcmp(argv[0], x->cmd) == 0) {
2235 debug_printf_exec("running builtin '%s'\n",
2237 rcode = x->function(argv);
2245 #if ENABLE_FEATURE_SH_STANDALONE
2246 /* Check if the command matches any busybox applets */
2247 if (strchr(argv[0], '/') == NULL) {
2248 int a = find_applet_by_name(argv[0]);
2250 #if BB_MMU /* see above why on NOMMU it is not allowed */
2251 if (APPLET_IS_NOEXEC(a)) {
2252 debug_printf_exec("running applet '%s'\n", argv[0]);
2253 run_applet_no_and_exit(a, argv);
2256 /* Re-exec ourselves */
2257 debug_printf_exec("re-execing applet '%s'\n", argv[0]);
2258 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2259 execv(bb_busybox_exec_path, argv);
2260 /* If they called chroot or otherwise made the binary no longer
2261 * executable, fall through */
2266 debug_printf_exec("execing '%s'\n", argv[0]);
2267 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2268 execvp(argv[0], argv);
2269 bb_perror_msg("can't exec '%s'", argv[0]);
2270 _exit(EXIT_FAILURE);
2274 static void reset_traps_to_defaults(void)
2282 for (sig = 0; sig < NSIG; sig++) {
2286 G.traps[sig] = NULL;
2287 /* There is no signal for 0 (EXIT) */
2290 /* there was a trap handler, we are removing it
2291 * (if sig has non-DFL handling,
2292 * we don't need to do anything) */
2293 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
2295 sigdelset(&G.blocked_set, sig);
2299 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
2301 #define clean_up_after_re_execute() ((void)0)
2305 static void re_execute_shell(const char *s) NORETURN;
2306 static void re_execute_shell(const char *s)
2308 struct variable *cur;
2309 char **argv, **pp, **pp2;
2312 /* 1:hush 2:-$<pid> 3:-!<pid> 4:-?<exitcode> 5:-D<depth> <vars...>
2313 * 6:-c 7:<cmd> <argN...> 8:NULL
2315 cnt = 8 + G.global_argc;
2316 for (cur = G.top_var; cur; cur = cur->next) {
2317 if (!cur->flg_export || cur->flg_read_only)
2320 G.argv_from_re_execing = pp = xzalloc(sizeof(argv[0]) * cnt);
2321 *pp++ = (char *) G.argv0_for_re_execing;
2322 *pp++ = xasprintf("-$%u", (unsigned) G.root_pid);
2323 *pp++ = xasprintf("-!%u", (unsigned) G.last_bg_pid);
2324 *pp++ = xasprintf("-?%u", (unsigned) G.last_return_code);
2325 #if ENABLE_HUSH_LOOPS
2326 *pp++ = xasprintf("-D%u", G.depth_of_loop);
2328 for (cur = G.top_var; cur; cur = cur->next) {
2329 if (cur->varstr == hush_version_str)
2331 if (cur->flg_read_only) {
2332 *pp++ = (char *) "-R";
2333 *pp++ = cur->varstr;
2334 } else if (!cur->flg_export) {
2335 *pp++ = (char *) "-V";
2336 *pp++ = cur->varstr;
2339 //TODO: pass functions
2340 /* We can pass activated traps here. Say, -Tnn:trap_string
2342 * However, POSIX says that subshells reset signals with traps
2344 * I tested bash-3.2 and it not only does that with true subshells
2345 * of the form ( list ), but with any forked children shells.
2346 * I set trap "echo W" WINCH; and then tried:
2348 * { echo 1; sleep 20; echo 2; } &
2349 * while true; do echo 1; sleep 20; echo 2; break; done &
2350 * true | { echo 1; sleep 20; echo 2; } | cat
2352 * In all these cases sending SIGWINCH to the child shell
2353 * did not run the trap. If I add trap "echo V" WINCH;
2354 * _inside_ group (just before echo 1), it works.
2356 * I conclude it means we don't need to pass active traps here.
2357 * exec syscall below resets them to SIG_DFL for us.
2359 *pp++ = (char *) "-c";
2361 pp2 = G.global_argv;
2364 /* *pp = NULL; - is already there */
2366 debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
2367 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2368 execv(bb_busybox_exec_path, G.argv_from_re_execing);
2369 /* Fallback. Useful for init=/bin/hush usage etc */
2370 if (G.argv0_for_re_execing[0] == '/')
2371 execv(G.argv0_for_re_execing, G.argv_from_re_execing);
2372 xfunc_error_retval = 127;
2373 bb_error_msg_and_die("can't re-execute the shell");
2376 static void clean_up_after_re_execute(void)
2378 char **pp = G.argv_from_re_execing;
2380 /* Must match re_execute_shell's allocations */
2384 #if ENABLE_HUSH_LOOPS
2388 G.argv_from_re_execing = NULL;
2393 static int run_list(struct pipe *pi);
2395 /* Called after [v]fork() in run_pipe()
2397 static void pseudo_exec(nommu_save_t *nommu_save,
2398 struct command *command,
2399 char **argv_expanded) NORETURN;
2400 static void pseudo_exec(nommu_save_t *nommu_save,
2401 struct command *command,
2402 char **argv_expanded)
2404 if (command->argv) {
2405 pseudo_exec_argv(nommu_save, command->argv,
2406 command->assignment_cnt, argv_expanded);
2409 if (command->group) {
2410 /* Cases when we are here:
2413 * ... | ( list ) | ...
2414 * ... | { list } | ...
2418 debug_printf_exec("pseudo_exec: run_list\n");
2419 reset_traps_to_defaults();
2420 rcode = run_list(command->group);
2421 /* OK to leak memory by not calling free_pipe_list,
2422 * since this process is about to exit */
2425 re_execute_shell(command->group_as_string);
2429 /* Case when we are here: ... | >file */
2430 debug_printf_exec("pseudo_exec'ed null command\n");
2431 _exit(EXIT_SUCCESS);
2435 static const char *get_cmdtext(struct pipe *pi)
2441 /* This is subtle. ->cmdtext is created only on first backgrounding.
2442 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
2443 * On subsequent bg argv is trashed, but we won't use it */
2446 argv = pi->cmds[0].argv;
2447 if (!argv || !argv[0]) {
2448 pi->cmdtext = xzalloc(1);
2453 do len += strlen(*argv) + 1; while (*++argv);
2454 pi->cmdtext = p = xmalloc(len);
2455 argv = pi->cmds[0].argv;
2457 len = strlen(*argv);
2458 memcpy(p, *argv, len);
2466 static void insert_bg_job(struct pipe *pi)
2468 struct pipe *thejob;
2471 /* Linear search for the ID of the job to use */
2473 for (thejob = G.job_list; thejob; thejob = thejob->next)
2474 if (thejob->jobid >= pi->jobid)
2475 pi->jobid = thejob->jobid + 1;
2477 /* Add thejob to the list of running jobs */
2479 thejob = G.job_list = xmalloc(sizeof(*thejob));
2481 for (thejob = G.job_list; thejob->next; thejob = thejob->next)
2483 thejob->next = xmalloc(sizeof(*thejob));
2484 thejob = thejob->next;
2487 /* Physically copy the struct job */
2488 memcpy(thejob, pi, sizeof(struct pipe));
2489 thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
2490 /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */
2491 for (i = 0; i < pi->num_cmds; i++) {
2492 // TODO: do we really need to have so many fields which are just dead weight
2493 // at execution stage?
2494 thejob->cmds[i].pid = pi->cmds[i].pid;
2495 /* all other fields are not used and stay zero */
2497 thejob->next = NULL;
2498 thejob->cmdtext = xstrdup(get_cmdtext(pi));
2500 /* We don't wait for background thejobs to return -- append it
2501 to the list of backgrounded thejobs and leave it alone */
2502 if (G_interactive_fd)
2503 printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext);
2504 G.last_bg_pid = thejob->cmds[0].pid;
2505 G.last_jobid = thejob->jobid;
2508 static void remove_bg_job(struct pipe *pi)
2510 struct pipe *prev_pipe;
2512 if (pi == G.job_list) {
2513 G.job_list = pi->next;
2515 prev_pipe = G.job_list;
2516 while (prev_pipe->next != pi)
2517 prev_pipe = prev_pipe->next;
2518 prev_pipe->next = pi->next;
2521 G.last_jobid = G.job_list->jobid;
2526 /* Remove a backgrounded job */
2527 static void delete_finished_bg_job(struct pipe *pi)
2530 pi->stopped_cmds = 0;
2536 /* Check to see if any processes have exited -- if they
2537 * have, figure out why and see if a job has completed */
2538 static int checkjobs(struct pipe* fg_pipe)
2548 debug_printf_jobs("checkjobs %p\n", fg_pipe);
2551 // if (G.handled_SIGCHLD == G.count_SIGCHLD)
2552 // /* avoid doing syscall, nothing there anyway */
2555 attributes = WUNTRACED;
2556 if (fg_pipe == NULL)
2557 attributes |= WNOHANG;
2559 /* Do we do this right?
2560 * bash-3.00# sleep 20 | false
2562 * [3]+ Stopped sleep 20 | false
2563 * bash-3.00# echo $?
2564 * 1 <========== bg pipe is not fully done, but exitcode is already known!
2567 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
2568 //are stopped. Testcase: "cat | cat" in a script (not on command line)
2569 // + killall -STOP cat
2576 // i = G.count_SIGCHLD;
2577 childpid = waitpid(-1, &status, attributes);
2578 if (childpid <= 0) {
2579 if (childpid && errno != ECHILD)
2580 bb_perror_msg("waitpid");
2581 // else /* Until next SIGCHLD, waitpid's are useless */
2582 // G.handled_SIGCHLD = i;
2585 dead = WIFEXITED(status) || WIFSIGNALED(status);
2588 if (WIFSTOPPED(status))
2589 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
2590 childpid, WSTOPSIG(status), WEXITSTATUS(status));
2591 if (WIFSIGNALED(status))
2592 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
2593 childpid, WTERMSIG(status), WEXITSTATUS(status));
2594 if (WIFEXITED(status))
2595 debug_printf_jobs("pid %d exited, exitcode %d\n",
2596 childpid, WEXITSTATUS(status));
2598 /* Were we asked to wait for fg pipe? */
2600 for (i = 0; i < fg_pipe->num_cmds; i++) {
2601 debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
2602 if (fg_pipe->cmds[i].pid != childpid)
2604 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
2606 fg_pipe->cmds[i].pid = 0;
2607 fg_pipe->alive_cmds--;
2608 if (i == fg_pipe->num_cmds - 1) {
2609 /* last process gives overall exitstatus */
2610 rcode = WEXITSTATUS(status);
2611 IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
2614 fg_pipe->cmds[i].is_stopped = 1;
2615 fg_pipe->stopped_cmds++;
2617 debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
2618 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
2619 if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) {
2620 /* All processes in fg pipe have exited/stopped */
2622 if (fg_pipe->alive_cmds)
2623 insert_bg_job(fg_pipe);
2627 /* There are still running processes in the fg pipe */
2628 goto wait_more; /* do waitpid again */
2630 /* it wasnt fg_pipe, look for process in bg pipes */
2634 /* We asked to wait for bg or orphaned children */
2635 /* No need to remember exitcode in this case */
2636 for (pi = G.job_list; pi; pi = pi->next) {
2637 for (i = 0; i < pi->num_cmds; i++) {
2638 if (pi->cmds[i].pid == childpid)
2639 goto found_pi_and_prognum;
2642 /* Happens when shell is used as init process (init=/bin/sh) */
2643 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
2644 continue; /* do waitpid again */
2646 found_pi_and_prognum:
2649 pi->cmds[i].pid = 0;
2651 if (!pi->alive_cmds) {
2652 if (G_interactive_fd)
2653 printf(JOB_STATUS_FORMAT, pi->jobid,
2654 "Done", pi->cmdtext);
2655 delete_finished_bg_job(pi);
2659 pi->cmds[i].is_stopped = 1;
2663 } /* while (waitpid succeeds)... */
2669 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
2672 int rcode = checkjobs(fg_pipe);
2673 /* Job finished, move the shell to the foreground */
2674 p = getpgid(0); /* pgid of our process */
2675 debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
2676 tcsetpgrp(G_interactive_fd, p);
2681 /* Start all the jobs, but don't wait for anything to finish.
2684 * Return code is normally -1, when the caller has to wait for children
2685 * to finish to determine the exit status of the pipe. If the pipe
2686 * is a simple builtin command, however, the action is done by the
2687 * time run_pipe returns, and the exit code is provided as the
2690 * Returns -1 only if started some children. IOW: we have to
2691 * mask out retvals of builtins etc with 0xff!
2693 * The only case when we do not need to [v]fork is when the pipe
2694 * is single, non-backgrounded, non-subshell command. Examples:
2695 * cmd ; ... { list } ; ...
2696 * cmd && ... { list } && ...
2697 * cmd || ... { list } || ...
2698 * If it is, then we can run cmd as a builtin, NOFORK [do we do this?],
2699 * or (if SH_STANDALONE) an applet, and we can run the { list }
2700 * with run_list(). If it isn't one of these, we fork and exec cmd.
2702 * Cases when we must fork:
2703 * non-single: cmd | cmd
2704 * backgrounded: cmd & { list } &
2705 * subshell: ( list ) [&]
2707 static int run_pipe(struct pipe *pi)
2709 static const char *const null_ptr = NULL;
2712 int pipefds[2]; /* pipefds[0] is for reading */
2713 struct command *command;
2714 char **argv_expanded;
2717 /* it is not always needed, but we aim to smaller code */
2718 int squirrel[] = { -1, -1, -1 };
2721 debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
2723 USE_HUSH_JOB(pi->pgrp = -1;)
2724 pi->stopped_cmds = 0;
2725 command = &(pi->cmds[0]);
2726 argv_expanded = NULL;
2728 if (pi->num_cmds != 1
2729 || pi->followup == PIPE_BG
2730 || command->grp_type == GRP_SUBSHELL
2737 debug_printf_exec(": group:%p argv:'%s'\n",
2738 command->group, command->argv ? command->argv[0] : "NONE");
2740 if (command->group) {
2741 #if ENABLE_HUSH_FUNCTIONS
2742 if (command->grp_type == GRP_FUNCTION) {
2743 /* func () { list } */
2744 bb_error_msg("here we ought to remember function definition, and go on");
2745 return EXIT_SUCCESS;
2749 debug_printf("non-subshell group\n");
2750 setup_redirects(command, squirrel);
2751 debug_printf_exec(": run_list\n");
2752 rcode = run_list(command->group) & 0xff;
2753 restore_redirects(squirrel);
2754 debug_printf_exec("run_pipe return %d\n", rcode);
2755 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2759 argv = command->argv ? command->argv : (char **) &null_ptr;
2761 const struct built_in_command *x;
2762 char **new_env = NULL;
2763 char **old_env = NULL;
2765 if (argv[command->assignment_cnt] == NULL) {
2766 /* Assignments, but no command */
2767 /* Ensure redirects take effect. Try "a=t >file" */
2768 setup_redirects(command, squirrel);
2769 restore_redirects(squirrel);
2770 /* Set shell variables */
2772 p = expand_string_to_string(*argv);
2773 debug_printf_exec("set shell var:'%s'->'%s'\n",
2775 set_local_var(p, 0, 0);
2778 /* Do we need to flag set_local_var() errors?
2779 * "assignment to readonly var" and "putenv error"
2781 return EXIT_SUCCESS;
2784 /* Expand the rest into (possibly) many strings each */
2785 argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
2787 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2788 if (strcmp(argv_expanded[0], x->cmd) != 0)
2790 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
2791 debug_printf("exec with redirects only\n");
2792 setup_redirects(command, NULL);
2793 rcode = EXIT_SUCCESS;
2794 goto clean_up_and_ret1;
2796 debug_printf("builtin inline %s\n", argv_expanded[0]);
2797 /* XXX setup_redirects acts on file descriptors, not FILEs.
2798 * This is perfect for work that comes after exec().
2799 * Is it really safe for inline use? Experimentally,
2800 * things seem to work with glibc. */
2801 setup_redirects(command, squirrel);
2802 new_env = expand_assignments(argv, command->assignment_cnt);
2803 old_env = putenv_all_and_save_old(new_env);
2804 debug_printf_exec(": builtin '%s' '%s'...\n",
2805 x->cmd, argv_expanded[1]);
2806 rcode = x->function(argv_expanded) & 0xff;
2807 #if ENABLE_FEATURE_SH_STANDALONE
2810 restore_redirects(squirrel);
2811 free_strings_and_unsetenv(new_env, 1);
2812 putenv_all(old_env);
2813 free(old_env); /* not free_strings()! */
2815 free(argv_expanded);
2816 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2817 debug_printf_exec("run_pipe return %d\n", rcode);
2820 #if ENABLE_FEATURE_SH_STANDALONE
2821 i = find_applet_by_name(argv_expanded[0]);
2822 if (i >= 0 && APPLET_IS_NOFORK(i)) {
2823 setup_redirects(command, squirrel);
2824 save_nofork_data(&G.nofork_save);
2825 new_env = expand_assignments(argv, command->assignment_cnt);
2826 old_env = putenv_all_and_save_old(new_env);
2827 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
2828 argv_expanded[0], argv_expanded[1]);
2829 rcode = run_nofork_applet_prime(&G.nofork_save, i, argv_expanded);
2830 goto clean_up_and_ret;
2833 /* It is neither builtin nor applet. We must fork. */
2837 /* NB: argv_expanded may already be created, and that
2838 * might include `cmd` runs! Do not rerun it! We *must*
2839 * use argv_expanded if it's non-NULL */
2841 /* Going to fork a child per each pipe member */
2845 for (i = 0; i < pi->num_cmds; i++) {
2847 volatile nommu_save_t nommu_save;
2848 nommu_save.new_env = NULL;
2849 nommu_save.old_env = NULL;
2850 nommu_save.argv = NULL;
2852 command = &(pi->cmds[i]);
2853 if (command->argv) {
2854 debug_printf_exec(": pipe member '%s' '%s'...\n",
2855 command->argv[0], command->argv[1]);
2857 debug_printf_exec(": pipe member with no argv\n");
2860 /* pipes are inserted between pairs of commands */
2863 if ((i + 1) < pi->num_cmds)
2866 command->pid = BB_MMU ? fork() : vfork();
2867 if (!command->pid) { /* child */
2869 die_sleep = 0; /* do not restore tty pgrp on xfunc death */
2871 /* Every child adds itself to new process group
2872 * with pgid == pid_of_first_child_in_pipe */
2873 if (G.run_list_level == 1 && G_interactive_fd) {
2876 if (pgrp < 0) /* true for 1st process only */
2878 if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
2879 /* We do it in *every* child, not just first,
2881 tcsetpgrp(G_interactive_fd, pgrp);
2885 xmove_fd(nextin, 0);
2886 xmove_fd(pipefds[1], 1); /* write end */
2888 close(pipefds[0]); /* read end */
2889 /* Like bash, explicit redirects override pipes,
2890 * and the pipe fd is available for dup'ing. */
2891 setup_redirects(command, NULL);
2893 /* Restore default handlers just prior to exec */
2894 /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
2896 /* Stores to nommu_save list of env vars putenv'ed
2897 * (NOMMU, on MMU we don't need that) */
2898 /* cast away volatility... */
2899 pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
2900 /* pseudo_exec() does not return */
2903 /* parent or error */
2905 die_sleep = -1; /* restore tty pgrp on xfunc death */
2908 /* Clean up after vforked child */
2909 clean_up_after_re_execute();
2910 free(nommu_save.argv);
2911 free_strings_and_unsetenv(nommu_save.new_env, 1);
2912 putenv_all(nommu_save.old_env);
2914 free(argv_expanded);
2915 argv_expanded = NULL;
2916 if (command->pid < 0) { /* [v]fork failed */
2917 /* Clearly indicate, was it fork or vfork */
2918 bb_perror_msg(BB_MMU ? "fork" : "vfork");
2922 /* Second and next children need to know pid of first one */
2924 pi->pgrp = command->pid;
2930 if ((i + 1) < pi->num_cmds)
2931 close(pipefds[1]); /* write end */
2932 /* Pass read (output) pipe end to next iteration */
2933 nextin = pipefds[0];
2936 if (!pi->alive_cmds) {
2937 debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
2941 debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
2945 #ifndef debug_print_tree
2946 static void debug_print_tree(struct pipe *pi, int lvl)
2948 static const char *const PIPE[] = {
2954 static const char *RES[] = {
2955 [RES_NONE ] = "NONE" ,
2958 [RES_THEN ] = "THEN" ,
2959 [RES_ELIF ] = "ELIF" ,
2960 [RES_ELSE ] = "ELSE" ,
2963 #if ENABLE_HUSH_LOOPS
2964 [RES_FOR ] = "FOR" ,
2965 [RES_WHILE] = "WHILE",
2966 [RES_UNTIL] = "UNTIL",
2968 [RES_DONE ] = "DONE" ,
2970 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
2973 #if ENABLE_HUSH_CASE
2974 [RES_CASE ] = "CASE" ,
2975 [RES_MATCH] = "MATCH",
2976 [RES_CASEI] = "CASEI",
2977 [RES_ESAC ] = "ESAC" ,
2979 [RES_XXXX ] = "XXXX" ,
2980 [RES_SNTX ] = "SNTX" ,
2982 static const char *const GRPTYPE[] = {
2985 #if ENABLE_HUSH_FUNCTIONS
2994 fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
2995 pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
2997 while (prn < pi->num_cmds) {
2998 struct command *command = &pi->cmds[prn];
2999 char **argv = command->argv;
3001 fprintf(stderr, "%*s prog %d assignment_cnt:%d",
3003 command->assignment_cnt);
3004 if (command->group) {
3005 fprintf(stderr, " group %s: (argv=%p)\n",
3006 GRPTYPE[command->grp_type],
3008 debug_print_tree(command->group, lvl+1);
3012 if (argv) while (*argv) {
3013 fprintf(stderr, " '%s'", *argv);
3016 fprintf(stderr, "\n");
3025 /* NB: called by pseudo_exec, and therefore must not modify any
3026 * global data until exec/_exit (we can be a child after vfork!) */
3027 static int run_list(struct pipe *pi)
3029 #if ENABLE_HUSH_CASE
3030 char *case_word = NULL;
3032 #if ENABLE_HUSH_LOOPS
3033 struct pipe *loop_top = NULL;
3034 char *for_varname = NULL;
3035 char **for_lcur = NULL;
3036 char **for_list = NULL;
3038 smallint flag_skip = 1;
3039 smalluint rcode = 0; /* probably just for compiler */
3040 #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
3041 smalluint cond_code = 0;
3043 enum { cond_code = 0, };
3045 /*enum reserved_style*/ smallint rword = RES_NONE;
3046 /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
3048 debug_printf_exec("run_list start lvl %d\n", G.run_list_level + 1);
3050 #if ENABLE_HUSH_LOOPS
3051 /* Check syntax for "for" */
3052 for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
3053 if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
3055 /* current word is FOR or IN (BOLD in comments below) */
3056 if (cpipe->next == NULL) {
3057 syntax("malformed for");
3058 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3061 /* "FOR v; do ..." and "for v IN a b; do..." are ok */
3062 if (cpipe->next->res_word == RES_DO)
3064 /* next word is not "do". It must be "in" then ("FOR v in ...") */
3065 if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
3066 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
3068 syntax("malformed for");
3069 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3075 /* Past this point, all code paths should jump to ret: label
3076 * in order to return, no direct "return" statements please.
3077 * This helps to ensure that no memory is leaked. */
3079 ////TODO: ctrl-Z handling needs re-thinking and re-testing
3082 /* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
3083 * We are saving state before entering outermost list ("while...done")
3084 * so that ctrl-Z will correctly background _entire_ outermost list,
3085 * not just a part of it (like "sleep 1 | exit 2") */
3086 if (++G.run_list_level == 1 && G_interactive_fd) {
3087 if (sigsetjmp(G.toplevel_jb, 1)) {
3088 /* ctrl-Z forked and we are parent; or ctrl-C.
3089 * Sighandler has longjmped us here */
3090 signal(SIGINT, SIG_IGN);
3091 signal(SIGTSTP, SIG_IGN);
3092 /* Restore level (we can be coming from deep inside
3094 G.run_list_level = 1;
3095 #if ENABLE_FEATURE_SH_STANDALONE
3096 if (G.nofork_save.saved) { /* if save area is valid */
3097 debug_printf_jobs("exiting nofork early\n");
3098 restore_nofork_data(&G.nofork_save);
3101 //// if (G.ctrl_z_flag) {
3102 //// /* ctrl-Z has forked and stored pid of the child in pi->pid.
3103 //// * Remember this child as background job */
3104 //// insert_bg_job(pi);
3106 /* ctrl-C. We just stop doing whatever we were doing */
3109 USE_HUSH_LOOPS(loop_top = NULL;)
3110 USE_HUSH_LOOPS(G.depth_of_loop = 0;)
3114 //// /* ctrl-Z handler will store pid etc in pi */
3115 //// G.toplevel_list = pi;
3116 //// G.ctrl_z_flag = 0;
3117 ////#if ENABLE_FEATURE_SH_STANDALONE
3118 //// G.nofork_save.saved = 0; /* in case we will run a nofork later */
3120 //// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
3121 //// signal(SIGINT, handler_ctrl_c);
3125 /* Go through list of pipes, (maybe) executing them. */
3126 for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
3130 IF_HAS_KEYWORDS(rword = pi->res_word;)
3131 IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
3132 debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
3133 rword, cond_code, skip_more_for_this_rword);
3134 #if ENABLE_HUSH_LOOPS
3135 if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
3136 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
3138 /* start of a loop: remember where loop starts */
3143 if (rword == skip_more_for_this_rword && flag_skip) {
3144 if (pi->followup == PIPE_SEQ)
3146 /* it is "<false> && CMD" or "<true> || CMD"
3147 * and we should not execute CMD */
3151 skip_more_for_this_rword = RES_XXXX;
3154 if (rword == RES_THEN) {
3155 /* "if <false> THEN cmd": skip cmd */
3159 if (rword == RES_ELSE || rword == RES_ELIF) {
3160 /* "if <true> then ... ELSE/ELIF cmd":
3161 * skip cmd and all following ones */
3166 #if ENABLE_HUSH_LOOPS
3167 if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
3169 /* first loop through for */
3171 static const char encoded_dollar_at[] ALIGN1 = {
3172 SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
3173 }; /* encoded representation of "$@" */
3174 static const char *const encoded_dollar_at_argv[] = {
3175 encoded_dollar_at, NULL
3176 }; /* argv list with one element: "$@" */
3179 vals = (char**)encoded_dollar_at_argv;
3180 if (pi->next->res_word == RES_IN) {
3181 /* if no variable values after "in" we skip "for" */
3182 if (!pi->next->cmds[0].argv)
3184 vals = pi->next->cmds[0].argv;
3185 } /* else: "for var; do..." -> assume "$@" list */
3186 /* create list of variable values */
3187 debug_print_strings("for_list made from", vals);
3188 for_list = expand_strvec_to_strvec(vals);
3189 for_lcur = for_list;
3190 debug_print_strings("for_list", for_list);
3191 for_varname = pi->cmds[0].argv[0];
3192 pi->cmds[0].argv[0] = NULL;
3194 free(pi->cmds[0].argv[0]);
3196 /* "for" loop is over, clean up */
3200 pi->cmds[0].argv[0] = for_varname;
3203 /* insert next value from for_lcur */
3204 //TODO: does it need escaping?
3205 pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
3206 pi->cmds[0].assignment_cnt = 1;
3208 if (rword == RES_IN) {
3209 continue; /* "for v IN list;..." - "in" has no cmds anyway */
3211 if (rword == RES_DONE) {
3212 continue; /* "done" has no cmds too */
3215 #if ENABLE_HUSH_CASE
3216 if (rword == RES_CASE) {
3217 case_word = expand_strvec_to_string(pi->cmds->argv);
3220 if (rword == RES_MATCH) {
3223 if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
3225 /* all prev words didn't match, does this one match? */
3226 argv = pi->cmds->argv;
3228 char *pattern = expand_string_to_string(*argv);
3229 /* TODO: which FNM_xxx flags to use? */
3230 cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
3232 if (cond_code == 0) { /* match! we will execute this branch */
3233 free(case_word); /* make future "word)" stop */
3241 if (rword == RES_CASEI) { /* inside of a case branch */
3243 continue; /* not matched yet, skip this pipe */
3246 /* Just pressing <enter> in shell should check for jobs.
3247 * OTOH, in non-interactive shell this is useless
3248 * and only leads to extra job checks */
3249 if (pi->num_cmds == 0) {
3250 if (G_interactive_fd)
3251 goto check_jobs_and_continue;
3255 /* After analyzing all keywords and conditions, we decided
3256 * to execute this pipe. NB: have to do checkjobs(NULL)
3257 * after run_pipe() to collect any background children,
3258 * even if list execution is to be stopped. */
3259 debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
3262 #if ENABLE_HUSH_LOOPS
3263 G.flag_break_continue = 0;
3265 rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
3267 /* we only ran a builtin: rcode is already known
3268 * and we don't need to wait for anything. */
3269 check_and_run_traps(0);
3270 #if ENABLE_HUSH_LOOPS
3271 /* was it "break" or "continue"? */
3272 if (G.flag_break_continue) {
3273 smallint fbc = G.flag_break_continue;
3274 /* we might fall into outer *loop*,
3275 * don't want to break it too */
3277 G.depth_break_continue--;
3278 if (G.depth_break_continue == 0)
3279 G.flag_break_continue = 0;
3280 /* else: e.g. "continue 2" should *break* once, *then* continue */
3281 } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
3282 if (G.depth_break_continue != 0 || fbc == BC_BREAK)
3283 goto check_jobs_and_break;
3284 /* "continue": simulate end of loop */
3289 } else if (pi->followup == PIPE_BG) {
3290 /* what does bash do with attempts to background builtins? */
3291 /* even bash 3.2 doesn't do that well with nested bg:
3292 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
3293 * I'm NOT treating inner &'s as jobs */
3294 check_and_run_traps(0);
3296 if (G.run_list_level == 1)
3299 rcode = 0; /* EXIT_SUCCESS */
3302 if (G.run_list_level == 1 && G_interactive_fd) {
3303 /* waits for completion, then fg's main shell */
3304 rcode = checkjobs_and_fg_shell(pi);
3305 check_and_run_traps(0);
3306 debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
3309 { /* this one just waits for completion */
3310 rcode = checkjobs(pi);
3311 check_and_run_traps(0);
3312 debug_printf_exec(": checkjobs returned %d\n", rcode);
3316 debug_printf_exec(": setting last_return_code=%d\n", rcode);
3317 G.last_return_code = rcode;
3319 /* Analyze how result affects subsequent commands */
3321 if (rword == RES_IF || rword == RES_ELIF)
3324 #if ENABLE_HUSH_LOOPS
3325 if (rword == RES_WHILE) {
3327 rcode = 0; /* "while false; do...done" - exitcode 0 */
3328 goto check_jobs_and_break;
3331 if (rword == RES_UNTIL) {
3333 check_jobs_and_break:
3339 if ((rcode == 0 && pi->followup == PIPE_OR)
3340 || (rcode != 0 && pi->followup == PIPE_AND)
3342 skip_more_for_this_rword = rword;
3345 check_jobs_and_continue:
3350 //// if (G.ctrl_z_flag) {
3351 //// /* ctrl-Z forked somewhere in the past, we are the child,
3352 //// * and now we completed running the list. Exit. */
3358 //// if (!G.run_list_level && G_interactive_fd) {
3359 //// signal(SIGTSTP, SIG_IGN);
3360 //// signal(SIGINT, SIG_IGN);
3363 debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
3364 #if ENABLE_HUSH_LOOPS
3369 #if ENABLE_HUSH_CASE
3375 /* Select which version we will use */
3376 static int run_and_free_list(struct pipe *pi)
3379 debug_printf_exec("run_and_free_list entered\n");
3381 debug_printf_exec(": run_list with %d members\n", pi->num_cmds);
3382 rcode = run_list(pi);
3384 /* free_pipe_list has the side effect of clearing memory.
3385 * In the long run that function can be merged with run_list,
3386 * but doing that now would hobble the debugging effort. */
3387 free_pipe_list(pi, /* indent: */ 0);
3388 debug_printf_exec("run_and_free_list return %d\n", rcode);
3393 /* Peek ahead in the in_str to find out if we have a "&n" construct,
3394 * as in "2>&1", that represents duplicating a file descriptor.
3395 * Return either -2 (syntax error), -1 (no &), or the number found.
3397 static int redirect_dup_num(struct in_str *input)
3399 int ch, d = 0, ok = 0;
3401 if (ch != '&') return -1;
3403 i_getch(input); /* get the & */
3407 return -3; /* "-" represents "close me" */
3409 while (isdigit(ch)) {
3410 d = d*10 + (ch-'0');
3417 bb_error_msg("ambiguous redirect");
3421 /* The src parameter allows us to peek forward to a possible &n syntax
3422 * for file descriptor duplication, e.g., "2>&1".
3423 * Return code is 0 normally, 1 if a syntax error is detected in src.
3424 * Resource errors (in xmalloc) cause the process to exit */
3425 static int setup_redirect(struct parse_context *ctx,
3428 struct in_str *input)
3430 struct command *command = ctx->command;
3431 struct redir_struct *redir;
3432 struct redir_struct **redirp;
3435 /* Check for a '2>&1' type redirect */
3436 dup_num = redirect_dup_num(input);
3438 return 1; /* syntax error */
3440 /* Create a new redir_struct and drop it onto the end of the linked list */
3441 redirp = &command->redirects;
3442 while ((redir = *redirp) != NULL) {
3443 redirp = &(redir->next);
3445 *redirp = redir = xzalloc(sizeof(*redir));
3446 /* redir->next = NULL; */
3447 /* redir->rd_filename = NULL; */
3448 redir->rd_type = style;
3449 redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
3451 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
3453 redir->dup = dup_num;
3454 if (dup_num != -1) {
3455 /* Erik had a check here that the file descriptor in question
3456 * is legit; I postpone that to "run time"
3457 * A "-" representation of "close me" shows up as a -3 here */
3458 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
3460 /* We do _not_ try to open the file that src points to,
3461 * since we need to return and let src be expanded first.
3462 * Set ctx->pending_redirect, so we know what to do at the
3463 * end of the next parsed word. */
3464 ctx->pending_redirect = redir;
3470 static struct pipe *new_pipe(void)
3473 pi = xzalloc(sizeof(struct pipe));
3474 /*pi->followup = 0; - deliberately invalid value */
3475 /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
3479 /* Command (member of a pipe) is complete. The only possible error here
3480 * is out of memory, in which case xmalloc exits. */
3481 static int done_command(struct parse_context *ctx)
3483 /* The command is really already in the pipe structure, so
3484 * advance the pipe counter and make a new, null command. */
3485 struct pipe *pi = ctx->pipe;
3486 struct command *command = ctx->command;
3489 if (command->group == NULL
3490 && command->argv == NULL
3491 && command->redirects == NULL
3493 debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
3494 return pi->num_cmds;
3497 debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
3499 debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
3502 /* Only real trickiness here is that the uncommitted
3503 * command structure is not counted in pi->num_cmds. */
3504 pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
3505 command = &pi->cmds[pi->num_cmds];
3506 memset(command, 0, sizeof(*command));
3508 ctx->command = command;
3509 /* but ctx->pipe and ctx->list_head remain unchanged */
3511 return pi->num_cmds; /* used only for 0/nonzero check */
3514 static void done_pipe(struct parse_context *ctx, pipe_style type)
3518 debug_printf_parse("done_pipe entered, followup %d\n", type);
3519 /* Close previous command */
3520 not_null = done_command(ctx);
3521 ctx->pipe->followup = type;
3522 IF_HAS_KEYWORDS(ctx->pipe->pi_inverted = ctx->ctx_inverted;)
3523 IF_HAS_KEYWORDS(ctx->ctx_inverted = 0;)
3524 IF_HAS_KEYWORDS(ctx->pipe->res_word = ctx->ctx_res_w;)
3526 /* Without this check, even just <enter> on command line generates
3527 * tree of three NOPs (!). Which is harmless but annoying.
3528 * IOW: it is safe to do it unconditionally.
3529 * RES_NONE case is for "for a in; do ..." (empty IN set)
3530 * to work, possibly other cases too. */
3531 if (not_null IF_HAS_KEYWORDS(|| ctx->ctx_res_w != RES_NONE)) {
3533 debug_printf_parse("done_pipe: adding new pipe: "
3534 "not_null:%d ctx->ctx_res_w:%d\n",
3535 not_null, ctx->ctx_res_w);
3537 ctx->pipe->next = new_p;
3539 /* RES_THEN, RES_DO etc are "sticky" -
3540 * they remain set for commands inside if/while.
3541 * This is used to control execution.
3542 * RES_FOR and RES_IN are NOT sticky (needed to support
3543 * cases where variable or value happens to match a keyword):
3545 #if ENABLE_HUSH_LOOPS
3546 if (ctx->ctx_res_w == RES_FOR
3547 || ctx->ctx_res_w == RES_IN)
3548 ctx->ctx_res_w = RES_NONE;
3550 #if ENABLE_HUSH_CASE
3551 if (ctx->ctx_res_w == RES_MATCH)
3552 ctx->ctx_res_w = RES_CASEI;
3554 ctx->command = NULL; /* trick done_command below */
3555 /* Create the memory for command, roughly:
3556 * ctx->pipe->cmds = new struct command;
3557 * ctx->command = &ctx->pipe->cmds[0];
3561 debug_printf_parse("done_pipe return\n");
3564 static void initialize_context(struct parse_context *ctx)
3566 memset(ctx, 0, sizeof(*ctx));
3567 ctx->pipe = ctx->list_head = new_pipe();
3568 /* Create the memory for command, roughly:
3569 * ctx->pipe->cmds = new struct command;
3570 * ctx->command = &ctx->pipe->cmds[0];
3576 /* If a reserved word is found and processed, parse context is modified
3577 * and 1 is returned.
3580 struct reserved_combo {
3583 unsigned char assignment_flag;
3587 FLAG_END = (1 << RES_NONE ),
3589 FLAG_IF = (1 << RES_IF ),
3590 FLAG_THEN = (1 << RES_THEN ),
3591 FLAG_ELIF = (1 << RES_ELIF ),
3592 FLAG_ELSE = (1 << RES_ELSE ),
3593 FLAG_FI = (1 << RES_FI ),
3595 #if ENABLE_HUSH_LOOPS
3596 FLAG_FOR = (1 << RES_FOR ),
3597 FLAG_WHILE = (1 << RES_WHILE),
3598 FLAG_UNTIL = (1 << RES_UNTIL),
3599 FLAG_DO = (1 << RES_DO ),
3600 FLAG_DONE = (1 << RES_DONE ),
3601 FLAG_IN = (1 << RES_IN ),
3603 #if ENABLE_HUSH_CASE
3604 FLAG_MATCH = (1 << RES_MATCH),
3605 FLAG_ESAC = (1 << RES_ESAC ),
3607 FLAG_START = (1 << RES_XXXX ),
3610 static const struct reserved_combo* match_reserved_word(o_string *word)
3612 /* Mostly a list of accepted follow-up reserved words.
3613 * FLAG_END means we are done with the sequence, and are ready
3614 * to turn the compound list into a command.
3615 * FLAG_START means the word must start a new compound list.
3617 static const struct reserved_combo reserved_list[] = {
3619 { "!", RES_NONE, NOT_ASSIGNMENT , 0 },
3620 { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START },
3621 { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
3622 { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN },
3623 { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI },
3624 { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
3626 #if ENABLE_HUSH_LOOPS
3627 { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
3628 { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3629 { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3630 { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
3631 { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE },
3632 { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
3634 #if ENABLE_HUSH_CASE
3635 { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
3636 { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
3639 const struct reserved_combo *r;
3641 for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
3642 if (strcmp(word->data, r->literal) == 0)
3647 static int reserved_word(o_string *word, struct parse_context *ctx)
3649 #if ENABLE_HUSH_CASE
3650 static const struct reserved_combo reserved_match = {
3651 "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
3654 const struct reserved_combo *r;
3656 r = match_reserved_word(word);
3660 debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
3661 #if ENABLE_HUSH_CASE
3662 if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE)
3663 /* "case word IN ..." - IN part starts first match part */
3664 r = &reserved_match;
3667 if (r->flag == 0) { /* '!' */
3668 if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
3669 syntax("! ! command");
3670 IF_HAS_KEYWORDS(ctx->ctx_res_w = RES_SNTX;)
3672 ctx->ctx_inverted = 1;
3675 if (r->flag & FLAG_START) {
3676 struct parse_context *old;
3677 old = xmalloc(sizeof(*old));
3678 debug_printf_parse("push stack %p\n", old);
3679 *old = *ctx; /* physical copy */
3680 initialize_context(ctx);
3682 } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
3684 ctx->ctx_res_w = RES_SNTX;
3687 ctx->ctx_res_w = r->res;
3688 ctx->old_flag = r->flag;
3689 if (ctx->old_flag & FLAG_END) {
3690 struct parse_context *old;
3691 done_pipe(ctx, PIPE_SEQ);
3692 debug_printf_parse("pop stack %p\n", ctx->stack);
3694 old->command->group = ctx->list_head;
3695 old->command->grp_type = GRP_NORMAL;
3697 o_addstr(&old->as_string, ctx->as_string.data);
3698 o_free_unsafe(&ctx->as_string);
3699 old->command->group_as_string = xstrdup(old->as_string.data);
3700 debug_printf_parse("pop, remembering as:'%s'\n",
3701 old->command->group_as_string);
3703 *ctx = *old; /* physical copy */
3706 word->o_assignment = r->assignment_flag;
3711 /* Word is complete, look at it and update parsing context.
3712 * Normal return is 0. Syntax errors return 1.
3713 * Note: on return, word is reset, but not o_free'd!
3715 static int done_word(o_string *word, struct parse_context *ctx)
3717 struct command *command = ctx->command;
3719 debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
3720 if (word->length == 0 && word->nonnull == 0) {
3721 debug_printf_parse("done_word return 0: true null, ignored\n");
3724 /* If this word wasn't an assignment, next ones definitely
3725 * can't be assignments. Even if they look like ones. */
3726 if (word->o_assignment != DEFINITELY_ASSIGNMENT
3727 && word->o_assignment != WORD_IS_KEYWORD
3729 word->o_assignment = NOT_ASSIGNMENT;
3731 if (word->o_assignment == DEFINITELY_ASSIGNMENT)
3732 command->assignment_cnt++;
3733 word->o_assignment = MAYBE_ASSIGNMENT;
3736 if (ctx->pending_redirect) {
3737 /* We do not glob in e.g. >*.tmp case. bash seems to glob here
3738 * only if run as "bash", not "sh" */
3739 ctx->pending_redirect->rd_filename = xstrdup(word->data);
3740 word->o_assignment = NOT_ASSIGNMENT;
3741 debug_printf("word stored in rd_filename: '%s'\n", word->data);
3743 /* "{ echo foo; } echo bar" - bad */
3744 /* NB: bash allows e.g.:
3745 * if true; then { echo foo; } fi
3746 * while if false; then false; fi do break; done
3748 if (command->group) {
3750 debug_printf_parse("done_word return 1: syntax error, "
3751 "groups and arglists don't mix\n");
3755 #if ENABLE_HUSH_CASE
3756 if (ctx->ctx_dsemicolon
3757 && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
3759 /* already done when ctx_dsemicolon was set to 1: */
3760 /* ctx->ctx_res_w = RES_MATCH; */
3761 ctx->ctx_dsemicolon = 0;
3764 if (!command->argv /* if it's the first word... */
3765 #if ENABLE_HUSH_LOOPS
3766 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
3767 && ctx->ctx_res_w != RES_IN
3770 debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
3771 if (reserved_word(word, ctx)) {
3773 debug_printf_parse("done_word return %d\n",
3774 (ctx->ctx_res_w == RES_SNTX));
3775 return (ctx->ctx_res_w == RES_SNTX);
3779 if (word->nonnull /* word had "xx" or 'xx' at least as part of it. */
3780 /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
3781 && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
3782 /* (otherwise it's known to be not empty and is already safe) */
3784 /* exclude "$@" - it can expand to no word despite "" */
3785 char *p = word->data;
3786 while (p[0] == SPECIAL_VAR_SYMBOL
3787 && (p[1] & 0x7f) == '@'
3788 && p[2] == SPECIAL_VAR_SYMBOL
3792 if (p == word->data || p[0] != '\0') {
3793 /* saw no "$@", or not only "$@" but some
3794 * real text is there too */
3795 /* insert "empty variable" reference, this makes
3796 * e.g. "", $empty"" etc to not disappear */
3797 o_addchr(word, SPECIAL_VAR_SYMBOL);
3798 o_addchr(word, SPECIAL_VAR_SYMBOL);
3801 command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
3802 debug_print_strings("word appended to argv", command->argv);
3806 ctx->pending_redirect = NULL;
3808 #if ENABLE_HUSH_LOOPS
3809 /* Force FOR to have just one word (variable name) */
3810 /* NB: basically, this makes hush see "for v in ..." syntax as if
3811 * as it is "for v; in ...". FOR and IN become two pipe structs
3813 if (ctx->ctx_res_w == RES_FOR) {
3814 //TODO: check that command->argv[0] is a valid variable name!
3815 done_pipe(ctx, PIPE_SEQ);
3818 #if ENABLE_HUSH_CASE
3819 /* Force CASE to have just one word */
3820 if (ctx->ctx_res_w == RES_CASE) {
3821 done_pipe(ctx, PIPE_SEQ);
3824 debug_printf_parse("done_word return 0\n");
3828 /* If a redirect is immediately preceded by a number, that number is
3829 * supposed to tell which file descriptor to redirect. This routine
3830 * looks for such preceding numbers. In an ideal world this routine
3831 * needs to handle all the following classes of redirects...
3832 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
3833 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
3834 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
3835 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
3836 * A -1 output from this program means no valid number was found, so the
3837 * caller should use the appropriate default for this redirection.
3839 static int redirect_opt_num(o_string *o)
3845 for (num = 0; num < o->length; num++) {
3846 if (!isdigit(o->data[num])) {
3850 num = atoi(o->data);
3856 #define parse_stream(pstring, input, end_trigger) \
3857 parse_stream(input, end_trigger)
3859 static struct pipe *parse_stream(char **pstring,
3860 struct in_str *input,
3862 static void parse_and_run_string(const char *s);
3864 #if ENABLE_HUSH_TICK
3865 static FILE *generate_stream_from_string(const char *s)
3868 int pid, channel[2];
3871 pid = BB_MMU ? fork() : vfork();
3873 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
3875 if (pid == 0) { /* child */
3877 die_sleep = 0; /* do not restore tty pgrp on xfunc death */
3879 /* Process substitution is not considered to be usual
3880 * 'command execution'.
3881 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
3888 close(channel[0]); /* NB: close _first_, then move fd! */
3889 xmove_fd(channel[1], 1);
3890 /* Prevent it from trying to handle ctrl-z etc */
3891 USE_HUSH_JOB(G.run_list_level = 1;)
3893 reset_traps_to_defaults();
3894 parse_and_run_string(s);
3895 _exit(G.last_return_code);
3897 /* We re-execute after vfork on NOMMU. This makes this script safe:
3898 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >BIG
3899 * huge=`cat BIG` # was blocking here forever
3902 re_execute_shell(s);
3908 die_sleep = -1; /* restore tty pgrp on xfunc death */
3910 clean_up_after_re_execute();
3912 pf = fdopen(channel[0], "r");
3916 /* Return code is exit status of the process that is run. */
3917 static int process_command_subs(o_string *dest, const char *s)
3920 struct in_str pipe_str;
3923 pf = generate_stream_from_string(s);
3926 close_on_exec_on(fileno(pf));
3928 /* Now send results of command back into original context */
3929 setup_file_in_str(&pipe_str, pf);
3931 while ((ch = i_getch(&pipe_str)) != EOF) {
3937 o_addchr(dest, '\n');
3940 o_addQchr(dest, ch);
3943 debug_printf("done reading from pipe, pclose()ing\n");
3944 /* Note: we got EOF, and we just close the read end of the pipe.
3945 * We do not wait for the `cmd` child to terminate. bash and ash do.
3947 * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec
3948 * `false`; echo $? - bash outputs "1"
3951 debug_printf("closed FILE from child. return 0\n");
3956 static int parse_group(o_string *dest, struct parse_context *ctx,
3957 struct in_str *input, int ch)
3959 /* dest contains characters seen prior to ( or {.
3960 * Typically it's empty, but for function defs,
3961 * it contains function name (without '()'). */
3962 struct pipe *pipe_list;
3964 struct command *command = ctx->command;
3966 debug_printf_parse("parse_group entered\n");
3967 #if ENABLE_HUSH_FUNCTIONS
3968 if (ch == 'F') { /* function definition? */
3969 bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
3970 //command->fname = dest->data;
3971 command->grp_type = GRP_FUNCTION;
3972 //TODO: review every o_reset() location... do they handle all o_string fields correctly?
3973 memset(dest, 0, sizeof(*dest));
3976 if (command->argv /* word [word](... */
3977 || dest->length /* word(... */
3978 || dest->nonnull /* ""(... */
3981 debug_printf_parse("parse_group return 1: "
3982 "syntax error, groups and arglists don't mix\n");
3988 command->grp_type = GRP_SUBSHELL;
3992 char *as_string = NULL;
3994 pipe_list = parse_stream(&as_string, input, endch);
3997 o_addstr(&ctx->as_string, as_string);
3999 /* empty ()/{} or parse error? */
4000 if (!pipe_list || pipe_list == ERR_PTR) {
4005 debug_printf_parse("parse_group return 1: "
4006 "parse_stream returned %p\n", pipe_list);
4009 command->group = pipe_list;
4011 as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
4012 command->group_as_string = as_string;
4013 debug_printf_parse("end of group, remembering as:'%s'\n",
4014 command->group_as_string);
4017 debug_printf_parse("parse_group return 0\n");
4019 /* command remains "open", available for possible redirects */
4022 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
4023 /* Subroutines for copying $(...) and `...` things */
4024 static void add_till_backquote(o_string *dest, struct in_str *input);
4026 static void add_till_single_quote(o_string *dest, struct in_str *input)
4029 int ch = i_getch(input);
4037 /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
4038 static void add_till_double_quote(o_string *dest, struct in_str *input)
4041 int ch = i_getch(input);
4044 if (ch == '\\') { /* \x. Copy both chars. */
4046 ch = i_getch(input);
4052 add_till_backquote(dest, input);
4056 //if (ch == '$') ...
4059 /* Process `cmd` - copy contents until "`" is seen. Complicated by
4061 * "Within the backquoted style of command substitution, backslash
4062 * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
4063 * The search for the matching backquote shall be satisfied by the first
4064 * backquote found without a preceding backslash; during this search,
4065 * if a non-escaped backquote is encountered within a shell comment,
4066 * a here-document, an embedded command substitution of the $(command)
4067 * form, or a quoted string, undefined results occur. A single-quoted
4068 * or double-quoted string that begins, but does not end, within the
4069 * "`...`" sequence produces undefined results."
4071 * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
4073 static void add_till_backquote(o_string *dest, struct in_str *input)
4076 int ch = i_getch(input);
4079 if (ch == '\\') { /* \x. Copy both chars unless it is \` */
4080 int ch2 = i_getch(input);
4081 if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
4090 /* Process $(cmd) - copy contents until ")" is seen. Complicated by
4091 * quoting and nested ()s.
4092 * "With the $(command) style of command substitution, all characters
4093 * following the open parenthesis to the matching closing parenthesis
4094 * constitute the command. Any valid shell script can be used for command,
4095 * except a script consisting solely of redirections which produces
4096 * unspecified results."
4098 * echo $(echo '(TEST)' BEST) (TEST) BEST
4099 * echo $(echo 'TEST)' BEST) TEST) BEST
4100 * echo $(echo \(\(TEST\) BEST) ((TEST) BEST
4102 static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
4106 int ch = i_getch(input);
4115 if (i_peek(input) == ')') {
4123 add_till_single_quote(dest, input);
4128 add_till_double_quote(dest, input);
4132 if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */
4133 ch = i_getch(input);
4141 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
4143 /* Return code: 0 for OK, 1 for syntax error */
4145 #define handle_dollar(as_string, dest, input) \
4146 handle_dollar(dest, input)
4148 static int handle_dollar(o_string *as_string,
4150 struct in_str *input)
4153 int ch = i_peek(input); /* first character after the $ */
4154 unsigned char quote_mask = dest->o_escape ? 0x80 : 0;
4156 debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
4158 ch = i_getch(input);
4160 if (as_string) o_addchr(as_string, ch);
4163 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4165 debug_printf_parse(": '%c'\n", ch);
4166 o_addchr(dest, ch | quote_mask);
4169 if (!isalnum(ch) && ch != '_')
4171 ch = i_getch(input);
4173 if (as_string) o_addchr(as_string, ch);
4176 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4177 } else if (isdigit(ch)) {
4179 ch = i_getch(input);
4181 if (as_string) o_addchr(as_string, ch);
4183 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4184 debug_printf_parse(": '%c'\n", ch);
4185 o_addchr(dest, ch | quote_mask);
4186 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4187 } else switch (ch) {
4189 case '!': /* last bg pid */
4190 case '?': /* last exit code */
4191 case '#': /* number of args */
4192 case '*': /* args */
4193 case '@': /* args */
4194 goto make_one_char_var;
4196 bool first_char, all_digits;
4198 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4199 ch = i_getch(input);
4201 if (as_string) o_addchr(as_string, ch);
4203 /* XXX maybe someone will try to escape the '}' */
4208 ch = i_getch(input);
4210 if (as_string) o_addchr(as_string, ch);
4217 /* ${#var}: length of var contents */
4219 else if (isdigit(ch)) {
4226 && ( (all_digits && !isdigit(ch))
4227 || (!all_digits && !isalnum(ch) && ch != '_')
4230 /* handle parameter expansions
4231 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
4236 case ':': /* null modifier */
4237 if (expansion == 0) {
4238 debug_printf_parse(": null modifier\n");
4243 #if 0 /* not implemented yet :( */
4244 case '#': /* remove prefix */
4245 case '%': /* remove suffix */
4246 if (expansion == 0) {
4247 debug_printf_parse(": remove suffix/prefix\n");
4253 case '-': /* default value */
4254 case '=': /* assign default */
4255 case '+': /* alternative */
4256 case '?': /* error indicate */
4257 debug_printf_parse(": parameter expansion\n");
4262 syntax("unterminated ${name}");
4263 debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
4268 debug_printf_parse(": '%c'\n", ch);
4269 o_addchr(dest, ch | quote_mask);
4273 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4276 #if (ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_TICK)
4281 ch = i_getch(input);
4283 if (as_string) o_addchr(as_string, ch);
4285 # if ENABLE_SH_MATH_SUPPORT
4286 if (i_peek(input) == '(') {
4287 ch = i_getch(input);
4289 if (as_string) o_addchr(as_string, ch);
4291 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4292 o_addchr(dest, /*quote_mask |*/ '+');
4296 add_till_closing_paren(dest, input, true);
4299 o_addstr(as_string, dest->data + pos);
4300 o_addchr(as_string, ')');
4301 o_addchr(as_string, ')');
4304 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4308 # if ENABLE_HUSH_TICK
4309 //int pos = dest->length;
4310 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4311 o_addchr(dest, quote_mask | '`');
4315 add_till_closing_paren(dest, input, false);
4318 o_addstr(as_string, dest->data + pos);
4319 o_addchr(as_string, '`');
4322 //debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
4323 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4329 ch = i_getch(input);
4331 if (as_string) o_addchr(as_string, ch);
4334 if (isalnum(ch)) { /* it's $_name or $_123 */
4340 /* $_ Shell or shell script name; or last cmd name */
4341 /* $- Option flags set by set builtin or shell options (-i etc) */
4343 o_addQchr(dest, '$');
4345 debug_printf_parse("handle_dollar return 0\n");
4350 #define parse_stream_dquoted(as_string, dest, input, dquote_end) \
4351 parse_stream_dquoted(dest, input, dquote_end)
4353 static int parse_stream_dquoted(o_string *as_string,
4355 struct in_str *input,
4362 ch = i_getch(input);
4364 if (as_string && ch != EOF)
4365 o_addchr(as_string, ch);
4367 if (ch == dquote_end) { /* may be only '"' or EOF */
4369 if (dest->o_assignment == NOT_ASSIGNMENT)
4370 dest->o_escape ^= 1;
4371 debug_printf_parse("parse_stream_dquoted return 0\n");
4375 syntax("unterminated \"");
4376 debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n");
4381 next = i_peek(input);
4383 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4384 ch, ch, dest->o_escape);
4388 debug_printf_parse("parse_stream_dquoted return 1: \\<eof>\n");
4392 * "The backslash retains its special meaning [in "..."]
4393 * only when followed by one of the following characters:
4394 * $, `, ", \, or <newline>. A double quote may be quoted
4395 * within double quotes by preceding it with a backslash.
4396 * If enabled, history expansion will be performed unless
4397 * an ! appearing in double quotes is escaped using
4398 * a backslash. The backslash preceding the ! is not removed."
4400 if (strchr("$`\"\\", next) != NULL) {
4401 o_addqchr(dest, i_getch(input));
4403 o_addqchr(dest, '\\');
4408 if (handle_dollar(as_string, dest, input) != 0) {
4409 debug_printf_parse("parse_stream_dquoted return 1: "
4410 "handle_dollar returned non-0\n");
4415 #if ENABLE_HUSH_TICK
4417 //int pos = dest->length;
4418 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4419 o_addchr(dest, 0x80 | '`');
4420 add_till_backquote(dest, input);
4421 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4422 //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
4426 o_addQchr(dest, ch);
4428 && (dest->o_assignment == MAYBE_ASSIGNMENT
4429 || dest->o_assignment == WORD_IS_KEYWORD)
4430 && is_assignment(dest->data)
4432 dest->o_assignment = DEFINITELY_ASSIGNMENT;
4438 * Scan input until EOF or end_trigger char.
4439 * Return a list of pipes to execute, or NULL on EOF
4440 * or if end_trigger character is met.
4441 * On syntax error, exit is shell is not interactive,
4442 * reset parsing machinery and start parsing anew,
4443 * or return ERR_PTR.
4445 static struct pipe *parse_stream(char **pstring,
4446 struct in_str *input,
4449 struct parse_context ctx;
4450 o_string dest = NULL_O_STRING;
4453 /* Double-quote state is handled in the state variable is_in_dquote.
4454 * A single-quote triggers a bypass of the main loop until its mate is
4455 * found. When recursing, quote state is passed in via dest->o_escape.
4457 debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
4458 end_trigger ? : 'X');
4460 G.ifs = get_local_var_value("IFS");
4465 #if ENABLE_HUSH_INTERACTIVE
4466 input->promptmode = 0; /* PS1 */
4468 /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */
4469 initialize_context(&ctx);
4473 const char *is_special;
4477 redir_type redir_style;
4480 if (parse_stream_dquoted(&ctx.as_string, &dest, input, '"')) {
4483 /* We reached closing '"' */
4486 ch = i_getch(input);
4487 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4488 ch, ch, dest.o_escape);
4491 if (done_word(&dest, &ctx)) {
4495 done_pipe(&ctx, PIPE_SEQ);
4497 /* If we got nothing... */
4498 // TODO: test script consisting of just "&"
4499 if (pi->num_cmds == 0
4500 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
4502 free_pipe_list(pi, 0);
4505 debug_printf_parse("parse_stream return %p\n", pi);
4507 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4509 *pstring = ctx.as_string.data;
4511 o_free_unsafe(&ctx.as_string);
4516 o_addchr(&ctx.as_string, ch);
4518 is_ifs = strchr(G.ifs, ch);
4519 is_special = strchr("<>;&|(){}#'" /* special outside of "str" */
4520 "\\$\"" USE_HUSH_TICK("`") /* always special */
4523 if (!is_special && !is_ifs) { /* ordinary char */
4524 o_addQchr(&dest, ch);
4525 if ((dest.o_assignment == MAYBE_ASSIGNMENT
4526 || dest.o_assignment == WORD_IS_KEYWORD)
4528 && is_assignment(dest.data)
4530 dest.o_assignment = DEFINITELY_ASSIGNMENT;
4536 if (done_word(&dest, &ctx)) {
4540 #if ENABLE_HUSH_CASE
4541 /* "case ... in <newline> word) ..." -
4542 * newlines are ignored (but ';' wouldn't be) */
4543 if (ctx.command->argv == NULL
4544 && ctx.ctx_res_w == RES_MATCH
4549 /* Treat newline as a command separator. */
4550 done_pipe(&ctx, PIPE_SEQ);
4551 dest.o_assignment = MAYBE_ASSIGNMENT;
4553 /* note: if (is_ifs) continue;
4554 * will still trigger for us */
4557 if (end_trigger && end_trigger == ch) {
4558 //TODO: disallow "{ cmd }" without semicolon
4559 if (done_word(&dest, &ctx)) {
4562 done_pipe(&ctx, PIPE_SEQ);
4563 dest.o_assignment = MAYBE_ASSIGNMENT;
4564 /* Do we sit outside of any if's, loops or case's? */
4566 IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
4568 debug_printf_parse("parse_stream return %p: "
4569 "end_trigger char found\n",
4573 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4575 *pstring = ctx.as_string.data;
4577 o_free_unsafe(&ctx.as_string);
4579 return ctx.list_head;
4585 if (dest.o_assignment == MAYBE_ASSIGNMENT) {
4586 /* ch is a special char and thus this word
4587 * cannot be an assignment */
4588 dest.o_assignment = NOT_ASSIGNMENT;
4593 next = i_peek(input);
4598 if (dest.length == 0) {
4601 if (ch == EOF || ch == '\n')
4604 /* note: we do not add it to &ctx.as_string */
4607 //TODO: go back one char?
4608 o_addchr(&ctx.as_string, '\n');
4611 o_addQchr(&dest, ch);
4619 o_addchr(&dest, '\\');
4620 ch = i_getch(input);
4621 o_addchr(&dest, ch);
4623 o_addchr(&ctx.as_string, ch);
4627 if (handle_dollar(&ctx.as_string, &dest, input) != 0) {
4628 debug_printf_parse("parse_stream parse error: "
4629 "handle_dollar returned non-0\n");
4636 ch = i_getch(input);
4638 syntax("unterminated '");
4642 o_addchr(&ctx.as_string, ch);
4646 if (dest.o_assignment == NOT_ASSIGNMENT)
4647 o_addqchr(&dest, ch);
4649 o_addchr(&dest, ch);
4654 is_in_dquote ^= 1; /* invert */
4655 if (dest.o_assignment == NOT_ASSIGNMENT)
4658 #if ENABLE_HUSH_TICK
4660 //int pos = dest.length;
4661 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4662 o_addchr(&dest, '`');
4663 add_till_backquote(&dest, input);
4664 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4665 //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos);
4670 redir_fd = redirect_opt_num(&dest);
4671 if (done_word(&dest, &ctx)) {
4674 redir_style = REDIRECT_OVERWRITE;
4676 redir_style = REDIRECT_APPEND;
4677 ch = i_getch(input);
4679 o_addchr(&ctx.as_string, ch);
4683 else if (next == '(') {
4684 syntax(">(process) not supported");
4688 setup_redirect(&ctx, redir_fd, redir_style, input);
4691 redir_fd = redirect_opt_num(&dest);
4692 if (done_word(&dest, &ctx)) {
4695 redir_style = REDIRECT_INPUT;
4697 redir_style = REDIRECT_HEREIS;
4698 ch = i_getch(input);
4700 o_addchr(&ctx.as_string, ch);
4702 } else if (next == '>') {
4703 redir_style = REDIRECT_IO;
4704 ch = i_getch(input);
4706 o_addchr(&ctx.as_string, ch);
4710 else if (next == '(') {
4711 syntax("<(process) not supported");
4715 setup_redirect(&ctx, redir_fd, redir_style, input);
4718 #if ENABLE_HUSH_CASE
4721 if (done_word(&dest, &ctx)) {
4724 done_pipe(&ctx, PIPE_SEQ);
4725 #if ENABLE_HUSH_CASE
4726 /* Eat multiple semicolons, detect
4727 * whether it means something special */
4732 ch = i_getch(input);
4734 o_addchr(&ctx.as_string, ch);
4736 if (ctx.ctx_res_w == RES_CASEI) {
4737 ctx.ctx_dsemicolon = 1;
4738 ctx.ctx_res_w = RES_MATCH;
4744 /* We just finished a cmd. New one may start
4745 * with an assignment */
4746 dest.o_assignment = MAYBE_ASSIGNMENT;
4749 if (done_word(&dest, &ctx)) {
4753 ch = i_getch(input);
4755 o_addchr(&ctx.as_string, ch);
4757 done_pipe(&ctx, PIPE_AND);
4759 done_pipe(&ctx, PIPE_BG);
4763 if (done_word(&dest, &ctx)) {
4766 #if ENABLE_HUSH_CASE
4767 if (ctx.ctx_res_w == RES_MATCH)
4768 break; /* we are in case's "word | word)" */
4770 if (next == '|') { /* || */
4771 ch = i_getch(input);
4773 o_addchr(&ctx.as_string, ch);
4775 done_pipe(&ctx, PIPE_OR);
4777 /* we could pick up a file descriptor choice here
4778 * with redirect_opt_num(), but bash doesn't do it.
4779 * "echo foo 2| cat" yields "foo 2". */
4784 #if ENABLE_HUSH_CASE
4785 /* "case... in [(]word)..." - skip '(' */
4786 if (ctx.ctx_res_w == RES_MATCH
4787 && ctx.command->argv == NULL /* not (word|(... */
4788 && dest.length == 0 /* not word(... */
4789 && dest.nonnull == 0 /* not ""(... */
4794 #if ENABLE_HUSH_FUNCTIONS
4795 if (dest.length != 0 /* not just () but word() */
4796 && dest.nonnull == 0 /* not a"b"c() */
4797 && ctx.command->argv == NULL /* it's the first word */
4798 //TODO: "func ( ) {...}" - note spaces - is valid format too in bash
4799 && i_peek(input) == ')'
4800 && !match_reserved_word(&dest)
4802 bb_error_msg("seems like a function definition");
4804 //if !BB_MMU o_addchr(&ctx.as_string...
4806 //TODO: do it properly.
4807 ch = i_getch(input);
4808 } while (ch == ' ' || ch == '\n');
4810 syntax("was expecting {");
4813 ch = 'F'; /* magic value */
4817 if (parse_group(&dest, &ctx, input, ch) != 0) {
4822 #if ENABLE_HUSH_CASE
4823 if (ctx.ctx_res_w == RES_MATCH)
4827 /* proper use of this character is caught by end_trigger:
4828 * if we see {, we call parse_group(..., end_trigger='}')
4829 * and it will match } earlier (not here). */
4830 syntax("unexpected } or )");
4834 bb_error_msg_and_die("BUG: unexpected %c\n", ch);
4840 struct parse_context *pctx;
4841 IF_HAS_KEYWORDS(struct parse_context *p2;)
4843 /* Clean up allocated tree.
4844 * Samples for finding leaks on syntax error recovery path.
4845 * Run them from interactive shell, watch pmap `pidof hush`.
4846 * while if false; then false; fi do break; done
4848 * while if false; then false; fi; do break; fi
4849 * Samples to catch leaks at execution:
4850 * while if (true | {true;}); then echo ok; fi; do break; done
4851 * while if (true | {true;}); then echo ok; fi; do (if echo ok; break; then :; fi) | cat; break; done
4855 /* Update pipe/command counts,
4856 * otherwise freeing may miss some */
4857 done_pipe(pctx, PIPE_SEQ);
4858 debug_printf_clean("freeing list %p from ctx %p\n",
4859 pctx->list_head, pctx);
4860 debug_print_tree(pctx->list_head, 0);
4861 free_pipe_list(pctx->list_head, 0);
4862 debug_printf_clean("freed list %p\n", pctx->list_head);
4864 o_free_unsafe(&pctx->as_string);
4866 IF_HAS_KEYWORDS(p2 = pctx->stack;)
4870 IF_HAS_KEYWORDS(pctx = p2;)
4871 } while (HAS_KEYWORDS && pctx);
4872 /* Free text, clear all dest fields */
4874 /* If we are not in top-level parse, we return,
4875 * our caller will propagate error.
4877 if (end_trigger != ';') {
4884 /* Discard cached input, force prompt */
4886 USE_HUSH_INTERACTIVE(input->promptme = 1;)
4891 /* Executing from string: eval, sh -c '...'
4892 * or from file: /etc/profile, . file, sh <script>, sh (intereactive)
4893 * end_trigger controls how often we stop parsing
4894 * NUL: parse all, execute, return
4895 * ';': parse till ';' or newline, execute, repeat till EOF
4897 static void parse_and_run_stream(struct in_str *inp, int end_trigger)
4900 struct pipe *pipe_list;
4902 pipe_list = parse_stream(NULL, inp, end_trigger);
4903 if (!pipe_list) /* EOF */
4905 debug_print_tree(pipe_list, 0);
4906 debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
4907 run_and_free_list(pipe_list);
4911 static void parse_and_run_string(const char *s)
4913 struct in_str input;
4914 setup_string_in_str(&input, s);
4915 parse_and_run_stream(&input, '\0');
4918 static void parse_and_run_file(FILE *f)
4920 struct in_str input;
4921 setup_file_in_str(&input, f);
4922 parse_and_run_stream(&input, ';');
4925 /* Called a few times only (or even once if "sh -c") */
4926 static void block_signals(int second_time)
4931 mask = (1 << SIGQUIT);
4932 if (G_interactive_fd) {
4936 //TODO | (1 << SIGHUP)
4938 | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
4943 G.non_DFL_mask = mask;
4946 sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
4950 sigaddset(&G.blocked_set, sig);
4954 sigdelset(&G.blocked_set, SIGCHLD);
4956 sigprocmask(SIG_SETMASK, &G.blocked_set,
4957 second_time ? NULL : &G.inherited_set);
4958 /* POSIX allows shell to re-enable SIGCHLD
4959 * even if it was SIG_IGN on entry */
4960 // G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
4962 signal(SIGCHLD, SIG_DFL); // SIGCHLD_handler);
4967 static void maybe_set_to_sigexit(int sig)
4969 void (*handler)(int);
4970 /* non_DFL_mask'ed signals are, well, masked,
4971 * no need to set handler for them.
4973 if (!((G.non_DFL_mask >> sig) & 1)) {
4974 handler = signal(sig, sigexit);
4975 if (handler == SIG_IGN) /* oops... restore back to IGN! */
4976 signal(sig, handler);
4979 /* Set handlers to restore tty pgrp and exit */
4980 static void set_fatal_handlers(void)
4982 /* We _must_ restore tty pgrp on fatal signals */
4984 maybe_set_to_sigexit(SIGILL );
4985 maybe_set_to_sigexit(SIGFPE );
4986 maybe_set_to_sigexit(SIGBUS );
4987 maybe_set_to_sigexit(SIGSEGV);
4988 maybe_set_to_sigexit(SIGTRAP);
4989 } /* else: hush is perfect. what SEGV? */
4990 maybe_set_to_sigexit(SIGABRT);
4991 /* bash 3.2 seems to handle these just like 'fatal' ones */
4992 maybe_set_to_sigexit(SIGPIPE);
4993 maybe_set_to_sigexit(SIGALRM);
4994 //TODO: disable and move down when proper SIGHUP handling is added
4995 maybe_set_to_sigexit(SIGHUP );
4996 /* if we are interactive, [SIGHUP,] SIGTERM and SIGINT are masked.
4997 * if we aren't interactive... but in this case
4998 * we never want to restore pgrp on exit, and this fn is not called */
4999 /*maybe_set_to_sigexit(SIGTERM);*/
5000 /*maybe_set_to_sigexit(SIGINT );*/
5004 static int set_mode(const char cstate, const char mode)
5006 int state = (cstate == '-' ? 1 : 0);
5008 case 'n': G.fake_mode = state; break;
5009 case 'x': /*G.debug_mode = state;*/ break;
5010 default: return EXIT_FAILURE;
5012 return EXIT_SUCCESS;
5015 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5016 int hush_main(int argc, char **argv)
5018 static const struct variable const_shell_ver = {
5020 .varstr = (char*)hush_version_str,
5021 .max_len = 1, /* 0 can provoke free(name) */
5025 int signal_mask_is_inited = 0;
5028 struct variable *cur_var;
5031 if (EXIT_SUCCESS) /* if EXIT_SUCCESS == 0, is already done */
5032 G.last_return_code = EXIT_SUCCESS;
5034 G.argv0_for_re_execing = argv[0];
5036 /* Deal with HUSH_VERSION */
5037 G.shell_ver = const_shell_ver; /* copying struct here */
5038 G.top_var = &G.shell_ver;
5039 debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
5040 unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
5041 /* Initialize our shell local variables with the values
5042 * currently living in the environment */
5043 cur_var = G.top_var;
5046 char *value = strchr(*e, '=');
5047 if (value) { /* paranoia */
5048 cur_var->next = xzalloc(sizeof(*cur_var));
5049 cur_var = cur_var->next;
5050 cur_var->varstr = *e;
5051 cur_var->max_len = strlen(*e);
5052 cur_var->flg_export = 1;
5056 debug_printf_env("putenv '%s'\n", hush_version_str);
5057 putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
5058 #if ENABLE_FEATURE_EDITING
5059 G.line_input_state = new_line_input_t(FOR_SHELL);
5061 G.global_argc = argc;
5062 G.global_argv = argv;
5063 /* Initialize some more globals to non-zero values */
5065 #if ENABLE_HUSH_INTERACTIVE
5066 if (ENABLE_FEATURE_EDITING)
5067 cmdedit_set_initial_prompt();
5071 /* Shell is non-interactive at first. We need to call
5072 * block_signals(0) if we are going to execute "sh <script>",
5073 * "sh -c <cmds>" or login shell's /etc/profile and friends.
5074 * If we later decide that we are interactive, we run block_signals(0)
5075 * (or re-run block_signals(1) if we ran block_signals(0) before)
5076 * in order to intercept (more) signals.
5080 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
5082 opt = getopt(argc, argv, "c:xins"
5092 G.root_pid = getpid();
5093 G.global_argv = argv + optind;
5094 if (!argv[optind]) {
5095 /* -c 'script' (no params): prevent empty $0 */
5096 *--G.global_argv = argv[0];
5098 } /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
5099 G.global_argc = argc - optind;
5100 block_signals(0); /* 0: called 1st time */
5101 parse_and_run_string(optarg);
5104 /* Well, we cannot just declare interactiveness,
5105 * we have to have some stuff (ctty, etc) */
5106 /* G_interactive_fd++; */
5109 /* "-s" means "read from stdin", but this is how we always
5110 * operate, so simply do nothing here. */
5114 G.root_pid = xatoi_u(optarg);
5117 G.last_bg_pid = xatoi_u(optarg);
5120 G.last_return_code = xatoi_u(optarg);
5122 # if ENABLE_HUSH_LOOPS
5124 G.depth_of_loop = xatoi_u(optarg);
5129 set_local_var(xstrdup(optarg), 0, opt == 'R');
5134 if (!set_mode('-', opt))
5138 fprintf(stderr, "Usage: sh [FILE]...\n"
5139 " or: sh -c command [args]...\n\n");
5145 } /* option parsing loop */
5148 G.root_pid = getpid();
5150 /* If we are login shell... */
5151 if (argv[0] && argv[0][0] == '-') {
5153 /* XXX what should argv be while sourcing /etc/profile? */
5154 debug_printf("sourcing /etc/profile\n");
5155 input = fopen_for_read("/etc/profile");
5156 if (input != NULL) {
5157 close_on_exec_on(fileno(input));
5158 block_signals(0); /* 0: called 1st time */
5159 signal_mask_is_inited = 1;
5160 parse_and_run_file(input);
5163 /* bash: after sourcing /etc/profile,
5164 * tries to source (in the given order):
5165 * ~/.bash_profile, ~/.bash_login, ~/.profile,
5166 * stopping of first found. --noprofile turns this off.
5167 * bash also sources ~/.bash_logout on exit.
5168 * If called as sh, skips .bash_XXX files.
5175 * "bash <script>" (which is never interactive (unless -i?))
5176 * sources $BASH_ENV here (without scanning $PATH).
5177 * If called as sh, does the same but with $ENV.
5179 debug_printf("running script '%s'\n", argv[optind]);
5180 G.global_argv = argv + optind;
5181 G.global_argc = argc - optind;
5182 input = xfopen_for_read(argv[optind]);
5183 close_on_exec_on(fileno(input));
5184 if (!signal_mask_is_inited)
5185 block_signals(0); /* 0: called 1st time */
5186 parse_and_run_file(input);
5187 #if ENABLE_FEATURE_CLEAN_UP
5193 /* Up to here, shell was non-interactive. Now it may become one.
5194 * NB: don't forget to (re)run block_signals(0/1) as needed.
5197 /* A shell is interactive if the '-i' flag was given, or if all of
5198 * the following conditions are met:
5200 * no arguments remaining or the -s flag given
5201 * standard input is a terminal
5202 * standard output is a terminal
5203 * Refer to Posix.2, the description of the 'sh' utility.
5206 if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
5207 G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
5208 debug_printf("saved_tty_pgrp:%d\n", G.saved_tty_pgrp);
5209 //TODO: "interactive" and "have job control" are two different things.
5210 //If tcgetpgrp fails here, "have job control" is false, but "interactive"
5211 //should stay on! Currently, we mix these into one.
5212 if (G.saved_tty_pgrp >= 0) {
5213 /* try to dup stdin to high fd#, >= 255 */
5214 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5215 if (G_interactive_fd < 0) {
5216 /* try to dup to any fd */
5217 G_interactive_fd = dup(STDIN_FILENO);
5218 if (G_interactive_fd < 0)
5220 G_interactive_fd = 0;
5222 // TODO: track & disallow any attempts of user
5223 // to (inadvertently) close/redirect it
5226 debug_printf("interactive_fd:%d\n", G_interactive_fd);
5227 if (G_interactive_fd) {
5230 /* We are indeed interactive shell, and we will perform
5231 * job control. Setting up for that. */
5233 close_on_exec_on(G_interactive_fd);
5234 /* If we were run as 'hush &', sleep until we are
5235 * in the foreground (tty pgrp == our pgrp).
5236 * If we get started under a job aware app (like bash),
5237 * make sure we are now in charge so we don't fight over
5238 * who gets the foreground */
5240 shell_pgrp = getpgrp();
5241 G.saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
5242 if (G.saved_tty_pgrp == shell_pgrp)
5244 /* send TTIN to ourself (should stop us) */
5245 kill(- shell_pgrp, SIGTTIN);
5247 /* Block some signals */
5248 block_signals(signal_mask_is_inited);
5249 /* Set other signals to restore saved_tty_pgrp */
5250 set_fatal_handlers();
5251 /* Put ourselves in our own process group */
5252 bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
5253 /* Grab control of the terminal */
5254 tcsetpgrp(G_interactive_fd, getpid());
5255 /* -1 is special - makes xfuncs longjmp, not exit
5256 * (we reset die_sleep = 0 whereever we [v]fork) */
5258 if (setjmp(die_jmp)) {
5259 /* xfunc has failed! die die die */
5260 hush_exit(xfunc_error_retval);
5262 } else if (!signal_mask_is_inited) {
5263 block_signals(0); /* 0: called 1st time */
5264 } /* else: block_signals(0) was done before */
5265 #elif ENABLE_HUSH_INTERACTIVE
5266 /* No job control compiled in, only prompt/line editing */
5267 if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
5268 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5269 if (G_interactive_fd < 0) {
5270 /* try to dup to any fd */
5271 G_interactive_fd = dup(STDIN_FILENO);
5272 if (G_interactive_fd < 0)
5274 G_interactive_fd = 0;
5277 if (G_interactive_fd) {
5278 close_on_exec_on(G_interactive_fd);
5279 block_signals(signal_mask_is_inited);
5280 } else if (!signal_mask_is_inited) {
5284 /* We have interactiveness code disabled */
5285 if (!signal_mask_is_inited) {
5290 * if interactive but not a login shell, sources ~/.bashrc
5291 * (--norc turns this off, --rcfile <file> overrides)
5294 if (!ENABLE_FEATURE_SH_EXTRA_QUIET && G_interactive_fd) {
5295 printf("\n\n%s hush - the humble shell\n", bb_banner);
5296 printf("Enter 'help' for a list of built-in commands.\n\n");
5299 parse_and_run_file(stdin);
5302 #if ENABLE_FEATURE_CLEAN_UP
5303 if (G.cwd != bb_msg_unknown)
5305 cur_var = G.top_var->next;
5307 struct variable *tmp = cur_var;
5308 if (!cur_var->max_len)
5309 free(cur_var->varstr);
5310 cur_var = cur_var->next;
5314 hush_exit(G.last_return_code);
5319 int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5320 int lash_main(int argc, char **argv)
5322 //bb_error_msg("lash is deprecated, please use hush instead");
5323 return hush_main(argc, argv);
5331 static int builtin_trap(char **argv)
5338 G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
5342 /* No args: print all trapped. This isn't 100% correct as we
5343 * should be escaping the cmd so that it can be pasted back in
5345 for (i = 0; i < NSIG; ++i)
5347 printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
5348 return EXIT_SUCCESS;
5353 /* If first arg is decimal: reset all specified signals */
5354 sig = bb_strtou(*argv, NULL, 10);
5360 sig = get_signum(*argv++);
5361 if (sig < 0 || sig >= NSIG) {
5363 /* Mimic bash message exactly */
5364 bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
5369 G.traps[sig] = xstrdup(new_cmd);
5371 debug_printf("trap: setting SIG%s (%i) to '%s'",
5372 get_signame(sig), sig, G.traps[sig]);
5374 /* There is no signal for 0 (EXIT) */
5379 sigaddset(&G.blocked_set, sig);
5381 /* There was a trap handler, we are removing it
5382 * (if sig has non-DFL handling,
5383 * we don't need to do anything) */
5384 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
5386 sigdelset(&G.blocked_set, sig);
5388 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5393 /* First arg is "-": reset all specified to default */
5394 /* First arg is "": ignore all specified */
5395 /* Everything else: execute first arg upon signal */
5397 bb_error_msg("trap: invalid arguments");
5398 return EXIT_FAILURE;
5400 if (NOT_LONE_DASH(*argv))
5406 static int builtin_true(char **argv UNUSED_PARAM)
5411 static int builtin_test(char **argv)
5418 return test_main(argc, argv - argc);
5421 static int builtin_echo(char **argv)
5428 return echo_main(argc, argv - argc);
5431 static int builtin_eval(char **argv)
5433 int rcode = EXIT_SUCCESS;
5436 char *str = expand_strvec_to_string(argv);
5438 * eval "echo Hi; done" ("done" is syntax error):
5439 * "echo Hi" will not execute too.
5441 parse_and_run_string(str);
5443 rcode = G.last_return_code;
5448 static int builtin_cd(char **argv)
5450 const char *newdir = argv[1];
5451 if (newdir == NULL) {
5452 /* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
5453 * bash says "bash: cd: HOME not set" and does nothing (exitcode 1)
5455 newdir = getenv("HOME") ? : "/";
5457 if (chdir(newdir)) {
5458 /* Mimic bash message exactly */
5459 bb_perror_msg("cd: %s", newdir);
5460 return EXIT_FAILURE;
5463 return EXIT_SUCCESS;
5466 static int builtin_exec(char **argv)
5468 if (*++argv == NULL)
5469 return EXIT_SUCCESS; /* bash does this */
5474 // FIXME: if exec fails, bash does NOT exit! We do...
5475 pseudo_exec_argv(&dummy, argv, 0, NULL);
5480 static int builtin_exit(char **argv)
5482 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
5483 //puts("exit"); /* bash does it */
5484 // TODO: warn if we have background jobs: "There are stopped jobs"
5485 // On second consecutive 'exit', exit anyway.
5486 if (*++argv == NULL)
5487 hush_exit(G.last_return_code);
5488 /* mimic bash: exit 123abc == exit 255 + error msg */
5489 xfunc_error_retval = 255;
5490 /* bash: exit -2 == exit 254, no error msg */
5491 hush_exit(xatoi(*argv) & 0xff);
5494 static int builtin_export(char **argv)
5496 if (*++argv == NULL) {
5498 // ash emits: export VAR='VAL'
5499 // bash: declare -x VAR="VAL"
5500 // (both also escape as needed (quotes, $, etc))
5505 return EXIT_SUCCESS;
5512 value = strchr(name, '=');
5514 /* They are exporting something without a =VALUE */
5515 struct variable *var;
5517 var = get_local_var(name);
5519 var->flg_export = 1;
5520 debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
5521 putenv(var->varstr);
5523 /* bash does not return an error when trying to export
5524 * an undefined variable. Do likewise. */
5527 set_local_var(xstrdup(name), 1, 0);
5530 return EXIT_SUCCESS;
5534 /* built-in 'fg' and 'bg' handler */
5535 static int builtin_fg_bg(char **argv)
5540 if (!G_interactive_fd)
5541 return EXIT_FAILURE;
5542 /* If they gave us no args, assume they want the last backgrounded task */
5544 for (pi = G.job_list; pi; pi = pi->next) {
5545 if (pi->jobid == G.last_jobid) {
5549 bb_error_msg("%s: no current job", argv[0]);
5550 return EXIT_FAILURE;
5552 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
5553 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
5554 return EXIT_FAILURE;
5556 for (pi = G.job_list; pi; pi = pi->next) {
5557 if (pi->jobid == jobnum) {
5561 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
5562 return EXIT_FAILURE;
5564 // TODO: bash prints a string representation
5565 // of job being foregrounded (like "sleep 1 | cat")
5566 if (argv[0][0] == 'f') {
5567 /* Put the job into the foreground. */
5568 tcsetpgrp(G_interactive_fd, pi->pgrp);
5571 /* Restart the processes in the job */
5572 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
5573 for (i = 0; i < pi->num_cmds; i++) {
5574 debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
5575 pi->cmds[i].is_stopped = 0;
5577 pi->stopped_cmds = 0;
5579 i = kill(- pi->pgrp, SIGCONT);
5581 if (errno == ESRCH) {
5582 delete_finished_bg_job(pi);
5583 return EXIT_SUCCESS;
5585 bb_perror_msg("kill (SIGCONT)");
5588 if (argv[0][0] == 'f') {
5590 return checkjobs_and_fg_shell(pi);
5592 return EXIT_SUCCESS;
5596 #if ENABLE_HUSH_HELP
5597 static int builtin_help(char **argv UNUSED_PARAM)
5599 const struct built_in_command *x;
5602 "Built-in commands:\n"
5603 "------------------\n");
5604 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
5605 printf("%s\t%s\n", x->cmd, x->descr);
5608 return EXIT_SUCCESS;
5613 static int builtin_jobs(char **argv UNUSED_PARAM)
5616 const char *status_string;
5618 for (job = G.job_list; job; job = job->next) {
5619 if (job->alive_cmds == job->stopped_cmds)
5620 status_string = "Stopped";
5622 status_string = "Running";
5624 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
5626 return EXIT_SUCCESS;
5630 static int builtin_pwd(char **argv UNUSED_PARAM)
5633 return EXIT_SUCCESS;
5636 static int builtin_read(char **argv)
5639 const char *name = argv[1] ? argv[1] : "REPLY";
5640 //TODO: check that argv[1] is a valid variable name
5642 string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
5643 return set_local_var(string, 0, 0);
5646 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
5647 * built-in 'set' handler
5649 * set [-abCefhmnuvx] [-o option] [argument...]
5650 * set [+abCefhmnuvx] [+o option] [argument...]
5651 * set -- [argument...]
5654 * Implementations shall support the options in both their hyphen and
5655 * plus-sign forms. These options can also be specified as options to sh.
5657 * Write out all variables and their values: set
5658 * Set $1, $2, and $3 and set "$#" to 3: set c a b
5659 * Turn on the -x and -v options: set -xv
5660 * Unset all positional parameters: set --
5661 * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
5662 * Set the positional parameters to the expansion of x, even if x expands
5663 * with a leading '-' or '+': set -- $x
5665 * So far, we only support "set -- [argument...]" and some of the short names.
5667 static int builtin_set(char **argv)
5670 char **pp, **g_argv;
5671 char *arg = *++argv;
5675 for (e = G.top_var; e; e = e->next)
5677 return EXIT_SUCCESS;
5681 if (!strcmp(arg, "--")) {
5686 if (arg[0] == '+' || arg[0] == '-') {
5687 for (n = 1; arg[n]; ++n)
5688 if (set_mode(arg[0], arg[n]))
5694 } while ((arg = *++argv) != NULL);
5695 /* Now argv[0] is 1st argument */
5697 /* Only reset global_argv if we didn't process anything */
5699 return EXIT_SUCCESS;
5702 /* NB: G.global_argv[0] ($0) is never freed/changed */
5703 g_argv = G.global_argv;
5704 if (G.global_args_malloced) {
5710 G.global_args_malloced = 1;
5711 pp = xzalloc(sizeof(pp[0]) * 2);
5712 pp[0] = g_argv[0]; /* retain $0 */
5715 /* This realloc's G.global_argv */
5716 G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
5723 return EXIT_SUCCESS;
5725 /* Nothing known, so abort */
5727 bb_error_msg("set: %s: invalid option", arg);
5728 return EXIT_FAILURE;
5731 static int builtin_shift(char **argv)
5737 if (n >= 0 && n < G.global_argc) {
5738 if (G.global_args_malloced) {
5741 free(G.global_argv[m++]);
5744 memmove(&G.global_argv[1], &G.global_argv[n+1],
5745 G.global_argc * sizeof(G.global_argv[0]));
5746 return EXIT_SUCCESS;
5748 return EXIT_FAILURE;
5751 static int builtin_source(char **argv)
5755 if (*++argv == NULL)
5756 return EXIT_FAILURE;
5758 /* XXX search through $PATH is missing */
5759 input = fopen_or_warn(*argv, "r");
5761 /* bb_perror_msg("%s", *argv); - done by fopen_or_warn */
5762 return EXIT_FAILURE;
5764 close_on_exec_on(fileno(input));
5766 /* Now run the file */
5768 /* XXX argv and argc are broken; need to save old G.global_argv
5769 * (pointer only is OK!) on this stack frame,
5770 * set G.global_argv=argv+1, recurse, and restore. */
5771 parse_and_run_file(input);
5773 return G.last_return_code;
5776 static int builtin_umask(char **argv)
5779 const char *arg = argv[1];
5781 //TODO: umask may take chmod-like symbolic masks
5782 new_umask = bb_strtou(arg, NULL, 8);
5784 //Message? bash examples:
5785 //bash: umask: 'q': invalid symbolic mode operator
5786 //bash: umask: 999: octal number out of range
5787 return EXIT_FAILURE;
5790 new_umask = umask(0);
5791 printf("%.3o\n", (unsigned) new_umask);
5792 /* fall through and restore new_umask which we set to 0 */
5795 return EXIT_SUCCESS;
5798 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
5799 static int builtin_unset(char **argv)
5805 return EXIT_SUCCESS;
5808 if (argv[0][0] == '-') {
5809 switch (argv[0][1]) {
5815 bb_error_msg("unset: %s: invalid option", *argv);
5816 return EXIT_FAILURE;
5818 //TODO: disallow "unset -vf ..." too
5825 if (unset_local_var(*argv)) {
5826 /* unset <nonexistent_var> doesn't fail.
5827 * Error is when one tries to unset RO var.
5828 * Message was printed by unset_local_var. */
5832 #if ENABLE_HUSH_FUNCTIONS
5834 unset_local_func(*argv);
5842 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
5843 static int builtin_wait(char **argv)
5845 int ret = EXIT_SUCCESS;
5848 if (*++argv == NULL) {
5849 /* Don't care about wait results */
5850 /* Note 1: must wait until there are no more children */
5851 /* Note 2: must be interruptible */
5853 * $ sleep 3 & sleep 6 & wait
5858 * $ sleep 3 & sleep 6 & wait
5862 * ^C <-- after ~4 sec from keyboard
5865 sigaddset(&G.blocked_set, SIGCHLD);
5866 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5869 if (errno == ECHILD)
5871 /* Wait for SIGCHLD or any other signal of interest */
5872 /* sigtimedwait with infinite timeout: */
5873 sig = sigwaitinfo(&G.blocked_set, NULL);
5875 sig = check_and_run_traps(sig);
5876 if (sig && sig != SIGCHLD) { /* see note 2 */
5882 sigdelset(&G.blocked_set, SIGCHLD);
5883 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5887 /* This is probably buggy wrt interruptible-ness */
5889 pid_t pid = bb_strtou(*argv, NULL, 10);
5891 /* mimic bash message */
5892 bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
5893 return EXIT_FAILURE;
5895 if (waitpid(pid, &status, 0) == pid) {
5896 if (WIFSIGNALED(status))
5897 ret = 128 + WTERMSIG(status);
5898 else if (WIFEXITED(status))
5899 ret = WEXITSTATUS(status);
5903 bb_perror_msg("wait %s", *argv);
5912 #if ENABLE_HUSH_LOOPS
5913 static int builtin_break(char **argv)
5915 if (G.depth_of_loop == 0) {
5916 bb_error_msg("%s: only meaningful in a loop", argv[0]);
5917 return EXIT_SUCCESS; /* bash compat */
5919 G.flag_break_continue++; /* BC_BREAK = 1 */
5920 G.depth_break_continue = 1;
5922 G.depth_break_continue = bb_strtou(argv[1], NULL, 10);
5923 if (errno || !G.depth_break_continue || argv[2]) {
5924 bb_error_msg("%s: bad arguments", argv[0]);
5925 G.flag_break_continue = BC_BREAK;
5926 G.depth_break_continue = UINT_MAX;
5929 if (G.depth_of_loop < G.depth_break_continue)
5930 G.depth_break_continue = G.depth_of_loop;
5931 return EXIT_SUCCESS;
5934 static int builtin_continue(char **argv)
5936 G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
5937 return builtin_break(argv);