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);
1802 o_free_unsafe(&dest);
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 /* "-" means "close me" and we use -3 for that */
2070 dup2(openfd, redir->fd);
2071 if (redir->dup == -1)
2079 static void restore_redirects(int squirrel[])
2082 for (i = 0; i < 3; i++) {
2085 /* We simply die on error */
2093 #define free_pipe_list(head, indent) free_pipe_list(head)
2094 #define free_pipe(pi, indent) free_pipe(pi)
2096 static void free_pipe_list(struct pipe *head, int indent);
2098 /* Return code is the exit status of the pipe */
2099 static void free_pipe(struct pipe *pi, int indent)
2102 struct command *command;
2103 struct redir_struct *r, *rnext;
2106 if (pi->stopped_cmds > 0) /* why? */
2108 debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
2109 for (i = 0; i < pi->num_cmds; i++) {
2110 command = &pi->cmds[i];
2111 debug_printf_clean("%s command %d:\n", indenter(indent), i);
2112 if (command->argv) {
2113 for (a = 0, p = command->argv; *p; a++, p++) {
2114 debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p);
2116 free_strings(command->argv);
2117 command->argv = NULL;
2119 /* not "else if": on syntax error, we may have both! */
2120 if (command->group) {
2121 debug_printf_clean("%s begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
2122 free_pipe_list(command->group, indent+3);
2123 debug_printf_clean("%s end group\n", indenter(indent));
2124 command->group = NULL;
2127 free(command->group_as_string);
2128 command->group_as_string = NULL;
2130 for (r = command->redirects; r; r = rnext) {
2131 debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->rd_type].descrip);
2133 /* guard against the case >$FOO, where foo is unset or blank */
2134 if (r->rd_filename) {
2135 debug_printf_clean(" %s\n", r->rd_filename);
2136 free(r->rd_filename);
2137 r->rd_filename = NULL;
2140 debug_printf_clean("&%d\n", r->dup);
2145 command->redirects = NULL;
2147 free(pi->cmds); /* children are an array, they get freed all at once */
2155 static void free_pipe_list(struct pipe *head, int indent)
2157 struct pipe *pi, *next;
2159 for (pi = head; pi; pi = next) {
2161 debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word);
2163 free_pipe(pi, indent);
2164 debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup);
2166 /*pi->next = NULL;*/
2173 typedef struct nommu_save_t {
2179 #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
2180 pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
2181 #define pseudo_exec(nommu_save, command, argv_expanded) \
2182 pseudo_exec(command, argv_expanded)
2185 /* Called after [v]fork() in run_pipe(), or from builtin_exec().
2187 * XXX no exit() here. If you don't exec, use _exit instead.
2188 * The at_exit handlers apparently confuse the calling process,
2189 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
2190 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2191 char **argv, int assignment_cnt,
2192 char **argv_expanded) NORETURN;
2193 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2194 char **argv, int assignment_cnt,
2195 char **argv_expanded)
2199 /* Case when we are here: ... | var=val | ... */
2200 if (!argv[assignment_cnt])
2201 _exit(EXIT_SUCCESS);
2203 new_env = expand_assignments(argv, assignment_cnt);
2205 putenv_all(new_env);
2206 free(new_env); /* optional */
2208 nommu_save->new_env = new_env;
2209 nommu_save->old_env = putenv_all_and_save_old(new_env);
2211 if (argv_expanded) {
2212 argv = argv_expanded;
2214 argv = expand_strvec_to_strvec(argv + assignment_cnt);
2216 nommu_save->argv = argv;
2220 /* On NOMMU, we must never block!
2221 * Example: { sleep 99999 | read line } & echo Ok
2222 * read builtin will block on read syscall, leaving parent blocked
2223 * in vfork. Therefore we can't do this:
2226 /* Check if the command matches any of the builtins.
2227 * Depending on context, this might be redundant. But it's
2228 * easier to waste a few CPU cycles than it is to figure out
2229 * if this is one of those cases.
2233 const struct built_in_command *x;
2234 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2235 if (strcmp(argv[0], x->cmd) == 0) {
2236 debug_printf_exec("running builtin '%s'\n",
2238 rcode = x->function(argv);
2246 #if ENABLE_FEATURE_SH_STANDALONE
2247 /* Check if the command matches any busybox applets */
2248 if (strchr(argv[0], '/') == NULL) {
2249 int a = find_applet_by_name(argv[0]);
2251 #if BB_MMU /* see above why on NOMMU it is not allowed */
2252 if (APPLET_IS_NOEXEC(a)) {
2253 debug_printf_exec("running applet '%s'\n", argv[0]);
2254 run_applet_no_and_exit(a, argv);
2257 /* Re-exec ourselves */
2258 debug_printf_exec("re-execing applet '%s'\n", argv[0]);
2259 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2260 execv(bb_busybox_exec_path, argv);
2261 /* If they called chroot or otherwise made the binary no longer
2262 * executable, fall through */
2267 debug_printf_exec("execing '%s'\n", argv[0]);
2268 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2269 execvp(argv[0], argv);
2270 bb_perror_msg("can't exec '%s'", argv[0]);
2271 _exit(EXIT_FAILURE);
2275 static void reset_traps_to_defaults(void)
2283 for (sig = 0; sig < NSIG; sig++) {
2287 G.traps[sig] = NULL;
2288 /* There is no signal for 0 (EXIT) */
2291 /* there was a trap handler, we are removing it
2292 * (if sig has non-DFL handling,
2293 * we don't need to do anything) */
2294 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
2296 sigdelset(&G.blocked_set, sig);
2300 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
2302 #define clean_up_after_re_execute() ((void)0)
2306 static void re_execute_shell(const char *s) NORETURN;
2307 static void re_execute_shell(const char *s)
2309 struct variable *cur;
2310 char **argv, **pp, **pp2;
2313 /* 1:hush 2:-$<pid> 3:-!<pid> 4:-?<exitcode> 5:-D<depth> <vars...>
2314 * 6:-c 7:<cmd> <argN...> 8:NULL
2316 cnt = 8 + G.global_argc;
2317 for (cur = G.top_var; cur; cur = cur->next) {
2318 if (!cur->flg_export || cur->flg_read_only)
2321 G.argv_from_re_execing = pp = xzalloc(sizeof(argv[0]) * cnt);
2322 *pp++ = (char *) G.argv0_for_re_execing;
2323 *pp++ = xasprintf("-$%u", (unsigned) G.root_pid);
2324 *pp++ = xasprintf("-!%u", (unsigned) G.last_bg_pid);
2325 *pp++ = xasprintf("-?%u", (unsigned) G.last_return_code);
2326 #if ENABLE_HUSH_LOOPS
2327 *pp++ = xasprintf("-D%u", G.depth_of_loop);
2329 for (cur = G.top_var; cur; cur = cur->next) {
2330 if (cur->varstr == hush_version_str)
2332 if (cur->flg_read_only) {
2333 *pp++ = (char *) "-R";
2334 *pp++ = cur->varstr;
2335 } else if (!cur->flg_export) {
2336 *pp++ = (char *) "-V";
2337 *pp++ = cur->varstr;
2340 //TODO: pass functions
2341 /* We can pass activated traps here. Say, -Tnn:trap_string
2343 * However, POSIX says that subshells reset signals with traps
2345 * I tested bash-3.2 and it not only does that with true subshells
2346 * of the form ( list ), but with any forked children shells.
2347 * I set trap "echo W" WINCH; and then tried:
2349 * { echo 1; sleep 20; echo 2; } &
2350 * while true; do echo 1; sleep 20; echo 2; break; done &
2351 * true | { echo 1; sleep 20; echo 2; } | cat
2353 * In all these cases sending SIGWINCH to the child shell
2354 * did not run the trap. If I add trap "echo V" WINCH;
2355 * _inside_ group (just before echo 1), it works.
2357 * I conclude it means we don't need to pass active traps here.
2358 * exec syscall below resets them to SIG_DFL for us.
2360 *pp++ = (char *) "-c";
2362 pp2 = G.global_argv;
2365 /* *pp = NULL; - is already there */
2367 debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
2368 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2369 execv(bb_busybox_exec_path, G.argv_from_re_execing);
2370 /* Fallback. Useful for init=/bin/hush usage etc */
2371 if (G.argv0_for_re_execing[0] == '/')
2372 execv(G.argv0_for_re_execing, G.argv_from_re_execing);
2373 xfunc_error_retval = 127;
2374 bb_error_msg_and_die("can't re-execute the shell");
2377 static void clean_up_after_re_execute(void)
2379 char **pp = G.argv_from_re_execing;
2381 /* Must match re_execute_shell's allocations */
2385 #if ENABLE_HUSH_LOOPS
2389 G.argv_from_re_execing = NULL;
2394 static int run_list(struct pipe *pi);
2396 /* Called after [v]fork() in run_pipe()
2398 static void pseudo_exec(nommu_save_t *nommu_save,
2399 struct command *command,
2400 char **argv_expanded) NORETURN;
2401 static void pseudo_exec(nommu_save_t *nommu_save,
2402 struct command *command,
2403 char **argv_expanded)
2405 if (command->argv) {
2406 pseudo_exec_argv(nommu_save, command->argv,
2407 command->assignment_cnt, argv_expanded);
2410 if (command->group) {
2411 /* Cases when we are here:
2414 * ... | ( list ) | ...
2415 * ... | { list } | ...
2419 debug_printf_exec("pseudo_exec: run_list\n");
2420 reset_traps_to_defaults();
2421 rcode = run_list(command->group);
2422 /* OK to leak memory by not calling free_pipe_list,
2423 * since this process is about to exit */
2426 re_execute_shell(command->group_as_string);
2430 /* Case when we are here: ... | >file */
2431 debug_printf_exec("pseudo_exec'ed null command\n");
2432 _exit(EXIT_SUCCESS);
2436 static const char *get_cmdtext(struct pipe *pi)
2442 /* This is subtle. ->cmdtext is created only on first backgrounding.
2443 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
2444 * On subsequent bg argv is trashed, but we won't use it */
2447 argv = pi->cmds[0].argv;
2448 if (!argv || !argv[0]) {
2449 pi->cmdtext = xzalloc(1);
2454 do len += strlen(*argv) + 1; while (*++argv);
2455 pi->cmdtext = p = xmalloc(len);
2456 argv = pi->cmds[0].argv;
2458 len = strlen(*argv);
2459 memcpy(p, *argv, len);
2467 static void insert_bg_job(struct pipe *pi)
2469 struct pipe *thejob;
2472 /* Linear search for the ID of the job to use */
2474 for (thejob = G.job_list; thejob; thejob = thejob->next)
2475 if (thejob->jobid >= pi->jobid)
2476 pi->jobid = thejob->jobid + 1;
2478 /* Add thejob to the list of running jobs */
2480 thejob = G.job_list = xmalloc(sizeof(*thejob));
2482 for (thejob = G.job_list; thejob->next; thejob = thejob->next)
2484 thejob->next = xmalloc(sizeof(*thejob));
2485 thejob = thejob->next;
2488 /* Physically copy the struct job */
2489 memcpy(thejob, pi, sizeof(struct pipe));
2490 thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
2491 /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */
2492 for (i = 0; i < pi->num_cmds; i++) {
2493 // TODO: do we really need to have so many fields which are just dead weight
2494 // at execution stage?
2495 thejob->cmds[i].pid = pi->cmds[i].pid;
2496 /* all other fields are not used and stay zero */
2498 thejob->next = NULL;
2499 thejob->cmdtext = xstrdup(get_cmdtext(pi));
2501 /* We don't wait for background thejobs to return -- append it
2502 to the list of backgrounded thejobs and leave it alone */
2503 if (G_interactive_fd)
2504 printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext);
2505 G.last_bg_pid = thejob->cmds[0].pid;
2506 G.last_jobid = thejob->jobid;
2509 static void remove_bg_job(struct pipe *pi)
2511 struct pipe *prev_pipe;
2513 if (pi == G.job_list) {
2514 G.job_list = pi->next;
2516 prev_pipe = G.job_list;
2517 while (prev_pipe->next != pi)
2518 prev_pipe = prev_pipe->next;
2519 prev_pipe->next = pi->next;
2522 G.last_jobid = G.job_list->jobid;
2527 /* Remove a backgrounded job */
2528 static void delete_finished_bg_job(struct pipe *pi)
2531 pi->stopped_cmds = 0;
2537 /* Check to see if any processes have exited -- if they
2538 * have, figure out why and see if a job has completed */
2539 static int checkjobs(struct pipe* fg_pipe)
2549 debug_printf_jobs("checkjobs %p\n", fg_pipe);
2552 // if (G.handled_SIGCHLD == G.count_SIGCHLD)
2553 // /* avoid doing syscall, nothing there anyway */
2556 attributes = WUNTRACED;
2557 if (fg_pipe == NULL)
2558 attributes |= WNOHANG;
2560 /* Do we do this right?
2561 * bash-3.00# sleep 20 | false
2563 * [3]+ Stopped sleep 20 | false
2564 * bash-3.00# echo $?
2565 * 1 <========== bg pipe is not fully done, but exitcode is already known!
2568 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
2569 //are stopped. Testcase: "cat | cat" in a script (not on command line)
2570 // + killall -STOP cat
2577 // i = G.count_SIGCHLD;
2578 childpid = waitpid(-1, &status, attributes);
2579 if (childpid <= 0) {
2580 if (childpid && errno != ECHILD)
2581 bb_perror_msg("waitpid");
2582 // else /* Until next SIGCHLD, waitpid's are useless */
2583 // G.handled_SIGCHLD = i;
2586 dead = WIFEXITED(status) || WIFSIGNALED(status);
2589 if (WIFSTOPPED(status))
2590 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
2591 childpid, WSTOPSIG(status), WEXITSTATUS(status));
2592 if (WIFSIGNALED(status))
2593 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
2594 childpid, WTERMSIG(status), WEXITSTATUS(status));
2595 if (WIFEXITED(status))
2596 debug_printf_jobs("pid %d exited, exitcode %d\n",
2597 childpid, WEXITSTATUS(status));
2599 /* Were we asked to wait for fg pipe? */
2601 for (i = 0; i < fg_pipe->num_cmds; i++) {
2602 debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
2603 if (fg_pipe->cmds[i].pid != childpid)
2605 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
2607 fg_pipe->cmds[i].pid = 0;
2608 fg_pipe->alive_cmds--;
2609 if (i == fg_pipe->num_cmds - 1) {
2610 /* last process gives overall exitstatus */
2611 rcode = WEXITSTATUS(status);
2612 IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
2615 fg_pipe->cmds[i].is_stopped = 1;
2616 fg_pipe->stopped_cmds++;
2618 debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
2619 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
2620 if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) {
2621 /* All processes in fg pipe have exited/stopped */
2623 if (fg_pipe->alive_cmds)
2624 insert_bg_job(fg_pipe);
2628 /* There are still running processes in the fg pipe */
2629 goto wait_more; /* do waitpid again */
2631 /* it wasnt fg_pipe, look for process in bg pipes */
2635 /* We asked to wait for bg or orphaned children */
2636 /* No need to remember exitcode in this case */
2637 for (pi = G.job_list; pi; pi = pi->next) {
2638 for (i = 0; i < pi->num_cmds; i++) {
2639 if (pi->cmds[i].pid == childpid)
2640 goto found_pi_and_prognum;
2643 /* Happens when shell is used as init process (init=/bin/sh) */
2644 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
2645 continue; /* do waitpid again */
2647 found_pi_and_prognum:
2650 pi->cmds[i].pid = 0;
2652 if (!pi->alive_cmds) {
2653 if (G_interactive_fd)
2654 printf(JOB_STATUS_FORMAT, pi->jobid,
2655 "Done", pi->cmdtext);
2656 delete_finished_bg_job(pi);
2660 pi->cmds[i].is_stopped = 1;
2664 } /* while (waitpid succeeds)... */
2670 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
2673 int rcode = checkjobs(fg_pipe);
2674 /* Job finished, move the shell to the foreground */
2675 p = getpgid(0); /* pgid of our process */
2676 debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
2677 tcsetpgrp(G_interactive_fd, p);
2682 /* Start all the jobs, but don't wait for anything to finish.
2685 * Return code is normally -1, when the caller has to wait for children
2686 * to finish to determine the exit status of the pipe. If the pipe
2687 * is a simple builtin command, however, the action is done by the
2688 * time run_pipe returns, and the exit code is provided as the
2691 * Returns -1 only if started some children. IOW: we have to
2692 * mask out retvals of builtins etc with 0xff!
2694 * The only case when we do not need to [v]fork is when the pipe
2695 * is single, non-backgrounded, non-subshell command. Examples:
2696 * cmd ; ... { list } ; ...
2697 * cmd && ... { list } && ...
2698 * cmd || ... { list } || ...
2699 * If it is, then we can run cmd as a builtin, NOFORK [do we do this?],
2700 * or (if SH_STANDALONE) an applet, and we can run the { list }
2701 * with run_list(). If it isn't one of these, we fork and exec cmd.
2703 * Cases when we must fork:
2704 * non-single: cmd | cmd
2705 * backgrounded: cmd & { list } &
2706 * subshell: ( list ) [&]
2708 static int run_pipe(struct pipe *pi)
2710 static const char *const null_ptr = NULL;
2713 int pipefds[2]; /* pipefds[0] is for reading */
2714 struct command *command;
2715 char **argv_expanded;
2718 /* it is not always needed, but we aim to smaller code */
2719 int squirrel[] = { -1, -1, -1 };
2722 debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
2724 USE_HUSH_JOB(pi->pgrp = -1;)
2725 pi->stopped_cmds = 0;
2726 command = &(pi->cmds[0]);
2727 argv_expanded = NULL;
2729 if (pi->num_cmds != 1
2730 || pi->followup == PIPE_BG
2731 || command->grp_type == GRP_SUBSHELL
2738 debug_printf_exec(": group:%p argv:'%s'\n",
2739 command->group, command->argv ? command->argv[0] : "NONE");
2741 if (command->group) {
2742 #if ENABLE_HUSH_FUNCTIONS
2743 if (command->grp_type == GRP_FUNCTION) {
2744 /* func () { list } */
2745 bb_error_msg("here we ought to remember function definition, and go on");
2746 return EXIT_SUCCESS;
2750 debug_printf("non-subshell group\n");
2751 setup_redirects(command, squirrel);
2752 debug_printf_exec(": run_list\n");
2753 rcode = run_list(command->group) & 0xff;
2754 restore_redirects(squirrel);
2755 debug_printf_exec("run_pipe return %d\n", rcode);
2756 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2760 argv = command->argv ? command->argv : (char **) &null_ptr;
2762 const struct built_in_command *x;
2763 char **new_env = NULL;
2764 char **old_env = NULL;
2766 if (argv[command->assignment_cnt] == NULL) {
2767 /* Assignments, but no command */
2768 /* Ensure redirects take effect. Try "a=t >file" */
2769 setup_redirects(command, squirrel);
2770 restore_redirects(squirrel);
2771 /* Set shell variables */
2773 p = expand_string_to_string(*argv);
2774 debug_printf_exec("set shell var:'%s'->'%s'\n",
2776 set_local_var(p, 0, 0);
2779 /* Do we need to flag set_local_var() errors?
2780 * "assignment to readonly var" and "putenv error"
2782 return EXIT_SUCCESS;
2785 /* Expand the rest into (possibly) many strings each */
2786 argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
2788 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2789 if (strcmp(argv_expanded[0], x->cmd) != 0)
2791 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
2792 debug_printf("exec with redirects only\n");
2793 setup_redirects(command, NULL);
2794 rcode = EXIT_SUCCESS;
2795 goto clean_up_and_ret1;
2797 debug_printf("builtin inline %s\n", argv_expanded[0]);
2798 /* XXX setup_redirects acts on file descriptors, not FILEs.
2799 * This is perfect for work that comes after exec().
2800 * Is it really safe for inline use? Experimentally,
2801 * things seem to work with glibc. */
2802 setup_redirects(command, squirrel);
2803 new_env = expand_assignments(argv, command->assignment_cnt);
2804 old_env = putenv_all_and_save_old(new_env);
2805 debug_printf_exec(": builtin '%s' '%s'...\n",
2806 x->cmd, argv_expanded[1]);
2807 rcode = x->function(argv_expanded) & 0xff;
2808 #if ENABLE_FEATURE_SH_STANDALONE
2811 restore_redirects(squirrel);
2812 free_strings_and_unsetenv(new_env, 1);
2813 putenv_all(old_env);
2814 free(old_env); /* not free_strings()! */
2816 free(argv_expanded);
2817 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2818 debug_printf_exec("run_pipe return %d\n", rcode);
2821 #if ENABLE_FEATURE_SH_STANDALONE
2822 i = find_applet_by_name(argv_expanded[0]);
2823 if (i >= 0 && APPLET_IS_NOFORK(i)) {
2824 setup_redirects(command, squirrel);
2825 save_nofork_data(&G.nofork_save);
2826 new_env = expand_assignments(argv, command->assignment_cnt);
2827 old_env = putenv_all_and_save_old(new_env);
2828 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
2829 argv_expanded[0], argv_expanded[1]);
2830 rcode = run_nofork_applet_prime(&G.nofork_save, i, argv_expanded);
2831 goto clean_up_and_ret;
2834 /* It is neither builtin nor applet. We must fork. */
2838 /* NB: argv_expanded may already be created, and that
2839 * might include `cmd` runs! Do not rerun it! We *must*
2840 * use argv_expanded if it's non-NULL */
2842 /* Going to fork a child per each pipe member */
2846 for (i = 0; i < pi->num_cmds; i++) {
2848 volatile nommu_save_t nommu_save;
2849 nommu_save.new_env = NULL;
2850 nommu_save.old_env = NULL;
2851 nommu_save.argv = NULL;
2853 command = &(pi->cmds[i]);
2854 if (command->argv) {
2855 debug_printf_exec(": pipe member '%s' '%s'...\n",
2856 command->argv[0], command->argv[1]);
2858 debug_printf_exec(": pipe member with no argv\n");
2861 /* pipes are inserted between pairs of commands */
2864 if ((i + 1) < pi->num_cmds)
2867 command->pid = BB_MMU ? fork() : vfork();
2868 if (!command->pid) { /* child */
2870 die_sleep = 0; /* do not restore tty pgrp on xfunc death */
2872 /* Every child adds itself to new process group
2873 * with pgid == pid_of_first_child_in_pipe */
2874 if (G.run_list_level == 1 && G_interactive_fd) {
2877 if (pgrp < 0) /* true for 1st process only */
2879 if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
2880 /* We do it in *every* child, not just first,
2882 tcsetpgrp(G_interactive_fd, pgrp);
2886 xmove_fd(nextin, 0);
2887 xmove_fd(pipefds[1], 1); /* write end */
2889 close(pipefds[0]); /* read end */
2890 /* Like bash, explicit redirects override pipes,
2891 * and the pipe fd is available for dup'ing. */
2892 setup_redirects(command, NULL);
2894 /* Restore default handlers just prior to exec */
2895 /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
2897 /* Stores to nommu_save list of env vars putenv'ed
2898 * (NOMMU, on MMU we don't need that) */
2899 /* cast away volatility... */
2900 pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
2901 /* pseudo_exec() does not return */
2904 /* parent or error */
2906 die_sleep = -1; /* restore tty pgrp on xfunc death */
2909 /* Clean up after vforked child */
2910 clean_up_after_re_execute();
2911 free(nommu_save.argv);
2912 free_strings_and_unsetenv(nommu_save.new_env, 1);
2913 putenv_all(nommu_save.old_env);
2915 free(argv_expanded);
2916 argv_expanded = NULL;
2917 if (command->pid < 0) { /* [v]fork failed */
2918 /* Clearly indicate, was it fork or vfork */
2919 bb_perror_msg(BB_MMU ? "fork" : "vfork");
2923 /* Second and next children need to know pid of first one */
2925 pi->pgrp = command->pid;
2931 if ((i + 1) < pi->num_cmds)
2932 close(pipefds[1]); /* write end */
2933 /* Pass read (output) pipe end to next iteration */
2934 nextin = pipefds[0];
2937 if (!pi->alive_cmds) {
2938 debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
2942 debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
2946 #ifndef debug_print_tree
2947 static void debug_print_tree(struct pipe *pi, int lvl)
2949 static const char *const PIPE[] = {
2955 static const char *RES[] = {
2956 [RES_NONE ] = "NONE" ,
2959 [RES_THEN ] = "THEN" ,
2960 [RES_ELIF ] = "ELIF" ,
2961 [RES_ELSE ] = "ELSE" ,
2964 #if ENABLE_HUSH_LOOPS
2965 [RES_FOR ] = "FOR" ,
2966 [RES_WHILE] = "WHILE",
2967 [RES_UNTIL] = "UNTIL",
2969 [RES_DONE ] = "DONE" ,
2971 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
2974 #if ENABLE_HUSH_CASE
2975 [RES_CASE ] = "CASE" ,
2976 [RES_MATCH] = "MATCH",
2977 [RES_CASEI] = "CASEI",
2978 [RES_ESAC ] = "ESAC" ,
2980 [RES_XXXX ] = "XXXX" ,
2981 [RES_SNTX ] = "SNTX" ,
2983 static const char *const GRPTYPE[] = {
2986 #if ENABLE_HUSH_FUNCTIONS
2995 fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
2996 pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
2998 while (prn < pi->num_cmds) {
2999 struct command *command = &pi->cmds[prn];
3000 char **argv = command->argv;
3002 fprintf(stderr, "%*s prog %d assignment_cnt:%d",
3004 command->assignment_cnt);
3005 if (command->group) {
3006 fprintf(stderr, " group %s: (argv=%p)\n",
3007 GRPTYPE[command->grp_type],
3009 debug_print_tree(command->group, lvl+1);
3013 if (argv) while (*argv) {
3014 fprintf(stderr, " '%s'", *argv);
3017 fprintf(stderr, "\n");
3026 /* NB: called by pseudo_exec, and therefore must not modify any
3027 * global data until exec/_exit (we can be a child after vfork!) */
3028 static int run_list(struct pipe *pi)
3030 #if ENABLE_HUSH_CASE
3031 char *case_word = NULL;
3033 #if ENABLE_HUSH_LOOPS
3034 struct pipe *loop_top = NULL;
3035 char *for_varname = NULL;
3036 char **for_lcur = NULL;
3037 char **for_list = NULL;
3039 smallint flag_skip = 1;
3040 smalluint rcode = 0; /* probably just for compiler */
3041 #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
3042 smalluint cond_code = 0;
3044 enum { cond_code = 0, };
3046 /*enum reserved_style*/ smallint rword = RES_NONE;
3047 /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
3049 debug_printf_exec("run_list start lvl %d\n", G.run_list_level + 1);
3051 #if ENABLE_HUSH_LOOPS
3052 /* Check syntax for "for" */
3053 for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
3054 if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
3056 /* current word is FOR or IN (BOLD in comments below) */
3057 if (cpipe->next == NULL) {
3058 syntax("malformed for");
3059 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3062 /* "FOR v; do ..." and "for v IN a b; do..." are ok */
3063 if (cpipe->next->res_word == RES_DO)
3065 /* next word is not "do". It must be "in" then ("FOR v in ...") */
3066 if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
3067 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
3069 syntax("malformed for");
3070 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3076 /* Past this point, all code paths should jump to ret: label
3077 * in order to return, no direct "return" statements please.
3078 * This helps to ensure that no memory is leaked. */
3080 ////TODO: ctrl-Z handling needs re-thinking and re-testing
3083 /* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
3084 * We are saving state before entering outermost list ("while...done")
3085 * so that ctrl-Z will correctly background _entire_ outermost list,
3086 * not just a part of it (like "sleep 1 | exit 2") */
3087 if (++G.run_list_level == 1 && G_interactive_fd) {
3088 if (sigsetjmp(G.toplevel_jb, 1)) {
3089 /* ctrl-Z forked and we are parent; or ctrl-C.
3090 * Sighandler has longjmped us here */
3091 signal(SIGINT, SIG_IGN);
3092 signal(SIGTSTP, SIG_IGN);
3093 /* Restore level (we can be coming from deep inside
3095 G.run_list_level = 1;
3096 #if ENABLE_FEATURE_SH_STANDALONE
3097 if (G.nofork_save.saved) { /* if save area is valid */
3098 debug_printf_jobs("exiting nofork early\n");
3099 restore_nofork_data(&G.nofork_save);
3102 //// if (G.ctrl_z_flag) {
3103 //// /* ctrl-Z has forked and stored pid of the child in pi->pid.
3104 //// * Remember this child as background job */
3105 //// insert_bg_job(pi);
3107 /* ctrl-C. We just stop doing whatever we were doing */
3110 USE_HUSH_LOOPS(loop_top = NULL;)
3111 USE_HUSH_LOOPS(G.depth_of_loop = 0;)
3115 //// /* ctrl-Z handler will store pid etc in pi */
3116 //// G.toplevel_list = pi;
3117 //// G.ctrl_z_flag = 0;
3118 ////#if ENABLE_FEATURE_SH_STANDALONE
3119 //// G.nofork_save.saved = 0; /* in case we will run a nofork later */
3121 //// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
3122 //// signal(SIGINT, handler_ctrl_c);
3126 /* Go through list of pipes, (maybe) executing them. */
3127 for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
3131 IF_HAS_KEYWORDS(rword = pi->res_word;)
3132 IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
3133 debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
3134 rword, cond_code, skip_more_for_this_rword);
3135 #if ENABLE_HUSH_LOOPS
3136 if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
3137 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
3139 /* start of a loop: remember where loop starts */
3144 if (rword == skip_more_for_this_rword && flag_skip) {
3145 if (pi->followup == PIPE_SEQ)
3147 /* it is "<false> && CMD" or "<true> || CMD"
3148 * and we should not execute CMD */
3152 skip_more_for_this_rword = RES_XXXX;
3155 if (rword == RES_THEN) {
3156 /* "if <false> THEN cmd": skip cmd */
3160 if (rword == RES_ELSE || rword == RES_ELIF) {
3161 /* "if <true> then ... ELSE/ELIF cmd":
3162 * skip cmd and all following ones */
3167 #if ENABLE_HUSH_LOOPS
3168 if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
3170 /* first loop through for */
3172 static const char encoded_dollar_at[] ALIGN1 = {
3173 SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
3174 }; /* encoded representation of "$@" */
3175 static const char *const encoded_dollar_at_argv[] = {
3176 encoded_dollar_at, NULL
3177 }; /* argv list with one element: "$@" */
3180 vals = (char**)encoded_dollar_at_argv;
3181 if (pi->next->res_word == RES_IN) {
3182 /* if no variable values after "in" we skip "for" */
3183 if (!pi->next->cmds[0].argv)
3185 vals = pi->next->cmds[0].argv;
3186 } /* else: "for var; do..." -> assume "$@" list */
3187 /* create list of variable values */
3188 debug_print_strings("for_list made from", vals);
3189 for_list = expand_strvec_to_strvec(vals);
3190 for_lcur = for_list;
3191 debug_print_strings("for_list", for_list);
3192 for_varname = pi->cmds[0].argv[0];
3193 pi->cmds[0].argv[0] = NULL;
3195 free(pi->cmds[0].argv[0]);
3197 /* "for" loop is over, clean up */
3201 pi->cmds[0].argv[0] = for_varname;
3204 /* insert next value from for_lcur */
3205 //TODO: does it need escaping?
3206 pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
3207 pi->cmds[0].assignment_cnt = 1;
3209 if (rword == RES_IN) {
3210 continue; /* "for v IN list;..." - "in" has no cmds anyway */
3212 if (rword == RES_DONE) {
3213 continue; /* "done" has no cmds too */
3216 #if ENABLE_HUSH_CASE
3217 if (rword == RES_CASE) {
3218 case_word = expand_strvec_to_string(pi->cmds->argv);
3221 if (rword == RES_MATCH) {
3224 if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
3226 /* all prev words didn't match, does this one match? */
3227 argv = pi->cmds->argv;
3229 char *pattern = expand_string_to_string(*argv);
3230 /* TODO: which FNM_xxx flags to use? */
3231 cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
3233 if (cond_code == 0) { /* match! we will execute this branch */
3234 free(case_word); /* make future "word)" stop */
3242 if (rword == RES_CASEI) { /* inside of a case branch */
3244 continue; /* not matched yet, skip this pipe */
3247 /* Just pressing <enter> in shell should check for jobs.
3248 * OTOH, in non-interactive shell this is useless
3249 * and only leads to extra job checks */
3250 if (pi->num_cmds == 0) {
3251 if (G_interactive_fd)
3252 goto check_jobs_and_continue;
3256 /* After analyzing all keywords and conditions, we decided
3257 * to execute this pipe. NB: have to do checkjobs(NULL)
3258 * after run_pipe() to collect any background children,
3259 * even if list execution is to be stopped. */
3260 debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
3263 #if ENABLE_HUSH_LOOPS
3264 G.flag_break_continue = 0;
3266 rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
3268 /* we only ran a builtin: rcode is already known
3269 * and we don't need to wait for anything. */
3270 check_and_run_traps(0);
3271 #if ENABLE_HUSH_LOOPS
3272 /* was it "break" or "continue"? */
3273 if (G.flag_break_continue) {
3274 smallint fbc = G.flag_break_continue;
3275 /* we might fall into outer *loop*,
3276 * don't want to break it too */
3278 G.depth_break_continue--;
3279 if (G.depth_break_continue == 0)
3280 G.flag_break_continue = 0;
3281 /* else: e.g. "continue 2" should *break* once, *then* continue */
3282 } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
3283 if (G.depth_break_continue != 0 || fbc == BC_BREAK)
3284 goto check_jobs_and_break;
3285 /* "continue": simulate end of loop */
3290 } else if (pi->followup == PIPE_BG) {
3291 /* what does bash do with attempts to background builtins? */
3292 /* even bash 3.2 doesn't do that well with nested bg:
3293 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
3294 * I'm NOT treating inner &'s as jobs */
3295 check_and_run_traps(0);
3297 if (G.run_list_level == 1)
3300 rcode = 0; /* EXIT_SUCCESS */
3303 if (G.run_list_level == 1 && G_interactive_fd) {
3304 /* waits for completion, then fg's main shell */
3305 rcode = checkjobs_and_fg_shell(pi);
3306 check_and_run_traps(0);
3307 debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
3310 { /* this one just waits for completion */
3311 rcode = checkjobs(pi);
3312 check_and_run_traps(0);
3313 debug_printf_exec(": checkjobs returned %d\n", rcode);
3317 debug_printf_exec(": setting last_return_code=%d\n", rcode);
3318 G.last_return_code = rcode;
3320 /* Analyze how result affects subsequent commands */
3322 if (rword == RES_IF || rword == RES_ELIF)
3325 #if ENABLE_HUSH_LOOPS
3326 if (rword == RES_WHILE) {
3328 rcode = 0; /* "while false; do...done" - exitcode 0 */
3329 goto check_jobs_and_break;
3332 if (rword == RES_UNTIL) {
3334 check_jobs_and_break:
3340 if ((rcode == 0 && pi->followup == PIPE_OR)
3341 || (rcode != 0 && pi->followup == PIPE_AND)
3343 skip_more_for_this_rword = rword;
3346 check_jobs_and_continue:
3351 //// if (G.ctrl_z_flag) {
3352 //// /* ctrl-Z forked somewhere in the past, we are the child,
3353 //// * and now we completed running the list. Exit. */
3359 //// if (!G.run_list_level && G_interactive_fd) {
3360 //// signal(SIGTSTP, SIG_IGN);
3361 //// signal(SIGINT, SIG_IGN);
3364 debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
3365 #if ENABLE_HUSH_LOOPS
3370 #if ENABLE_HUSH_CASE
3376 /* Select which version we will use */
3377 static int run_and_free_list(struct pipe *pi)
3380 debug_printf_exec("run_and_free_list entered\n");
3382 debug_printf_exec(": run_list with %d members\n", pi->num_cmds);
3383 rcode = run_list(pi);
3385 /* free_pipe_list has the side effect of clearing memory.
3386 * In the long run that function can be merged with run_list,
3387 * but doing that now would hobble the debugging effort. */
3388 free_pipe_list(pi, /* indent: */ 0);
3389 debug_printf_exec("run_and_free_list return %d\n", rcode);
3394 /* Peek ahead in the in_str to find out if we have a "&n" construct,
3395 * as in "2>&1", that represents duplicating a file descriptor.
3396 * Return either -2 (syntax error), -1 (no &), or the number found.
3398 static int redirect_dup_num(struct in_str *input)
3400 int ch, d = 0, ok = 0;
3402 if (ch != '&') return -1;
3404 i_getch(input); /* get the & */
3408 return -3; /* "-" represents "close me" */
3410 while (isdigit(ch)) {
3411 d = d*10 + (ch-'0');
3418 bb_error_msg("ambiguous redirect");
3422 /* The src parameter allows us to peek forward to a possible &n syntax
3423 * for file descriptor duplication, e.g., "2>&1".
3424 * Return code is 0 normally, 1 if a syntax error is detected in src.
3425 * Resource errors (in xmalloc) cause the process to exit */
3426 static int setup_redirect(struct parse_context *ctx,
3429 struct in_str *input)
3431 struct command *command = ctx->command;
3432 struct redir_struct *redir;
3433 struct redir_struct **redirp;
3436 /* Check for a '2>&1' type redirect */
3437 dup_num = redirect_dup_num(input);
3439 return 1; /* syntax error */
3441 /* Create a new redir_struct and drop it onto the end of the linked list */
3442 redirp = &command->redirects;
3443 while ((redir = *redirp) != NULL) {
3444 redirp = &(redir->next);
3446 *redirp = redir = xzalloc(sizeof(*redir));
3447 /* redir->next = NULL; */
3448 /* redir->rd_filename = NULL; */
3449 redir->rd_type = style;
3450 redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
3452 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
3454 redir->dup = dup_num;
3455 if (dup_num != -1) {
3456 /* Erik had a check here that the file descriptor in question
3457 * is legit; I postpone that to "run time"
3458 * A "-" representation of "close me" shows up as a -3 here */
3459 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
3461 /* We do _not_ try to open the file that src points to,
3462 * since we need to return and let src be expanded first.
3463 * Set ctx->pending_redirect, so we know what to do at the
3464 * end of the next parsed word. */
3465 ctx->pending_redirect = redir;
3471 static struct pipe *new_pipe(void)
3474 pi = xzalloc(sizeof(struct pipe));
3475 /*pi->followup = 0; - deliberately invalid value */
3476 /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
3480 /* Command (member of a pipe) is complete. The only possible error here
3481 * is out of memory, in which case xmalloc exits. */
3482 static int done_command(struct parse_context *ctx)
3484 /* The command is really already in the pipe structure, so
3485 * advance the pipe counter and make a new, null command. */
3486 struct pipe *pi = ctx->pipe;
3487 struct command *command = ctx->command;
3490 if (command->group == NULL
3491 && command->argv == NULL
3492 && command->redirects == NULL
3494 debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
3495 return pi->num_cmds;
3498 debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
3500 debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
3503 /* Only real trickiness here is that the uncommitted
3504 * command structure is not counted in pi->num_cmds. */
3505 pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
3506 command = &pi->cmds[pi->num_cmds];
3507 memset(command, 0, sizeof(*command));
3509 ctx->command = command;
3510 /* but ctx->pipe and ctx->list_head remain unchanged */
3512 return pi->num_cmds; /* used only for 0/nonzero check */
3515 static void done_pipe(struct parse_context *ctx, pipe_style type)
3519 debug_printf_parse("done_pipe entered, followup %d\n", type);
3520 /* Close previous command */
3521 not_null = done_command(ctx);
3522 ctx->pipe->followup = type;
3523 IF_HAS_KEYWORDS(ctx->pipe->pi_inverted = ctx->ctx_inverted;)
3524 IF_HAS_KEYWORDS(ctx->ctx_inverted = 0;)
3525 IF_HAS_KEYWORDS(ctx->pipe->res_word = ctx->ctx_res_w;)
3527 /* Without this check, even just <enter> on command line generates
3528 * tree of three NOPs (!). Which is harmless but annoying.
3529 * IOW: it is safe to do it unconditionally.
3530 * RES_NONE case is for "for a in; do ..." (empty IN set)
3531 * to work, possibly other cases too. */
3532 if (not_null IF_HAS_KEYWORDS(|| ctx->ctx_res_w != RES_NONE)) {
3534 debug_printf_parse("done_pipe: adding new pipe: "
3535 "not_null:%d ctx->ctx_res_w:%d\n",
3536 not_null, ctx->ctx_res_w);
3538 ctx->pipe->next = new_p;
3540 /* RES_THEN, RES_DO etc are "sticky" -
3541 * they remain set for commands inside if/while.
3542 * This is used to control execution.
3543 * RES_FOR and RES_IN are NOT sticky (needed to support
3544 * cases where variable or value happens to match a keyword):
3546 #if ENABLE_HUSH_LOOPS
3547 if (ctx->ctx_res_w == RES_FOR
3548 || ctx->ctx_res_w == RES_IN)
3549 ctx->ctx_res_w = RES_NONE;
3551 #if ENABLE_HUSH_CASE
3552 if (ctx->ctx_res_w == RES_MATCH)
3553 ctx->ctx_res_w = RES_CASEI;
3555 ctx->command = NULL; /* trick done_command below */
3556 /* Create the memory for command, roughly:
3557 * ctx->pipe->cmds = new struct command;
3558 * ctx->command = &ctx->pipe->cmds[0];
3562 debug_printf_parse("done_pipe return\n");
3565 static void initialize_context(struct parse_context *ctx)
3567 memset(ctx, 0, sizeof(*ctx));
3568 ctx->pipe = ctx->list_head = new_pipe();
3569 /* Create the memory for command, roughly:
3570 * ctx->pipe->cmds = new struct command;
3571 * ctx->command = &ctx->pipe->cmds[0];
3577 /* If a reserved word is found and processed, parse context is modified
3578 * and 1 is returned.
3581 struct reserved_combo {
3584 unsigned char assignment_flag;
3588 FLAG_END = (1 << RES_NONE ),
3590 FLAG_IF = (1 << RES_IF ),
3591 FLAG_THEN = (1 << RES_THEN ),
3592 FLAG_ELIF = (1 << RES_ELIF ),
3593 FLAG_ELSE = (1 << RES_ELSE ),
3594 FLAG_FI = (1 << RES_FI ),
3596 #if ENABLE_HUSH_LOOPS
3597 FLAG_FOR = (1 << RES_FOR ),
3598 FLAG_WHILE = (1 << RES_WHILE),
3599 FLAG_UNTIL = (1 << RES_UNTIL),
3600 FLAG_DO = (1 << RES_DO ),
3601 FLAG_DONE = (1 << RES_DONE ),
3602 FLAG_IN = (1 << RES_IN ),
3604 #if ENABLE_HUSH_CASE
3605 FLAG_MATCH = (1 << RES_MATCH),
3606 FLAG_ESAC = (1 << RES_ESAC ),
3608 FLAG_START = (1 << RES_XXXX ),
3611 static const struct reserved_combo* match_reserved_word(o_string *word)
3613 /* Mostly a list of accepted follow-up reserved words.
3614 * FLAG_END means we are done with the sequence, and are ready
3615 * to turn the compound list into a command.
3616 * FLAG_START means the word must start a new compound list.
3618 static const struct reserved_combo reserved_list[] = {
3620 { "!", RES_NONE, NOT_ASSIGNMENT , 0 },
3621 { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START },
3622 { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
3623 { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN },
3624 { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI },
3625 { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
3627 #if ENABLE_HUSH_LOOPS
3628 { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
3629 { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3630 { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3631 { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
3632 { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE },
3633 { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
3635 #if ENABLE_HUSH_CASE
3636 { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
3637 { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
3640 const struct reserved_combo *r;
3642 for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
3643 if (strcmp(word->data, r->literal) == 0)
3648 static int reserved_word(o_string *word, struct parse_context *ctx)
3650 #if ENABLE_HUSH_CASE
3651 static const struct reserved_combo reserved_match = {
3652 "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
3655 const struct reserved_combo *r;
3657 r = match_reserved_word(word);
3661 debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
3662 #if ENABLE_HUSH_CASE
3663 if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE)
3664 /* "case word IN ..." - IN part starts first match part */
3665 r = &reserved_match;
3668 if (r->flag == 0) { /* '!' */
3669 if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
3670 syntax("! ! command");
3671 IF_HAS_KEYWORDS(ctx->ctx_res_w = RES_SNTX;)
3673 ctx->ctx_inverted = 1;
3676 if (r->flag & FLAG_START) {
3677 struct parse_context *old;
3678 old = xmalloc(sizeof(*old));
3679 debug_printf_parse("push stack %p\n", old);
3680 *old = *ctx; /* physical copy */
3681 initialize_context(ctx);
3683 } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
3685 ctx->ctx_res_w = RES_SNTX;
3688 ctx->ctx_res_w = r->res;
3689 ctx->old_flag = r->flag;
3690 if (ctx->old_flag & FLAG_END) {
3691 struct parse_context *old;
3692 done_pipe(ctx, PIPE_SEQ);
3693 debug_printf_parse("pop stack %p\n", ctx->stack);
3695 old->command->group = ctx->list_head;
3696 old->command->grp_type = GRP_NORMAL;
3698 o_addstr(&old->as_string, ctx->as_string.data);
3699 o_free_unsafe(&ctx->as_string);
3700 old->command->group_as_string = xstrdup(old->as_string.data);
3701 debug_printf_parse("pop, remembering as:'%s'\n",
3702 old->command->group_as_string);
3704 *ctx = *old; /* physical copy */
3707 word->o_assignment = r->assignment_flag;
3712 /* Word is complete, look at it and update parsing context.
3713 * Normal return is 0. Syntax errors return 1.
3714 * Note: on return, word is reset, but not o_free'd!
3716 static int done_word(o_string *word, struct parse_context *ctx)
3718 struct command *command = ctx->command;
3720 debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
3721 if (word->length == 0 && word->nonnull == 0) {
3722 debug_printf_parse("done_word return 0: true null, ignored\n");
3725 /* If this word wasn't an assignment, next ones definitely
3726 * can't be assignments. Even if they look like ones. */
3727 if (word->o_assignment != DEFINITELY_ASSIGNMENT
3728 && word->o_assignment != WORD_IS_KEYWORD
3730 word->o_assignment = NOT_ASSIGNMENT;
3732 if (word->o_assignment == DEFINITELY_ASSIGNMENT)
3733 command->assignment_cnt++;
3734 word->o_assignment = MAYBE_ASSIGNMENT;
3737 if (ctx->pending_redirect) {
3738 /* We do not glob in e.g. >*.tmp case. bash seems to glob here
3739 * only if run as "bash", not "sh" */
3740 ctx->pending_redirect->rd_filename = xstrdup(word->data);
3741 word->o_assignment = NOT_ASSIGNMENT;
3742 debug_printf("word stored in rd_filename: '%s'\n", word->data);
3744 /* "{ echo foo; } echo bar" - bad */
3745 /* NB: bash allows e.g.:
3746 * if true; then { echo foo; } fi
3747 * while if false; then false; fi do break; done
3749 if (command->group) {
3751 debug_printf_parse("done_word return 1: syntax error, "
3752 "groups and arglists don't mix\n");
3756 #if ENABLE_HUSH_CASE
3757 if (ctx->ctx_dsemicolon
3758 && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
3760 /* already done when ctx_dsemicolon was set to 1: */
3761 /* ctx->ctx_res_w = RES_MATCH; */
3762 ctx->ctx_dsemicolon = 0;
3765 if (!command->argv /* if it's the first word... */
3766 #if ENABLE_HUSH_LOOPS
3767 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
3768 && ctx->ctx_res_w != RES_IN
3771 debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
3772 if (reserved_word(word, ctx)) {
3774 debug_printf_parse("done_word return %d\n",
3775 (ctx->ctx_res_w == RES_SNTX));
3776 return (ctx->ctx_res_w == RES_SNTX);
3780 if (word->nonnull /* word had "xx" or 'xx' at least as part of it. */
3781 /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
3782 && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
3783 /* (otherwise it's known to be not empty and is already safe) */
3785 /* exclude "$@" - it can expand to no word despite "" */
3786 char *p = word->data;
3787 while (p[0] == SPECIAL_VAR_SYMBOL
3788 && (p[1] & 0x7f) == '@'
3789 && p[2] == SPECIAL_VAR_SYMBOL
3793 if (p == word->data || p[0] != '\0') {
3794 /* saw no "$@", or not only "$@" but some
3795 * real text is there too */
3796 /* insert "empty variable" reference, this makes
3797 * e.g. "", $empty"" etc to not disappear */
3798 o_addchr(word, SPECIAL_VAR_SYMBOL);
3799 o_addchr(word, SPECIAL_VAR_SYMBOL);
3802 command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
3803 debug_print_strings("word appended to argv", command->argv);
3807 ctx->pending_redirect = NULL;
3809 #if ENABLE_HUSH_LOOPS
3810 /* Force FOR to have just one word (variable name) */
3811 /* NB: basically, this makes hush see "for v in ..." syntax as if
3812 * as it is "for v; in ...". FOR and IN become two pipe structs
3814 if (ctx->ctx_res_w == RES_FOR) {
3815 //TODO: check that command->argv[0] is a valid variable name!
3816 done_pipe(ctx, PIPE_SEQ);
3819 #if ENABLE_HUSH_CASE
3820 /* Force CASE to have just one word */
3821 if (ctx->ctx_res_w == RES_CASE) {
3822 done_pipe(ctx, PIPE_SEQ);
3825 debug_printf_parse("done_word return 0\n");
3829 /* If a redirect is immediately preceded by a number, that number is
3830 * supposed to tell which file descriptor to redirect. This routine
3831 * looks for such preceding numbers. In an ideal world this routine
3832 * needs to handle all the following classes of redirects...
3833 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
3834 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
3835 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
3836 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
3837 * A -1 output from this program means no valid number was found, so the
3838 * caller should use the appropriate default for this redirection.
3840 static int redirect_opt_num(o_string *o)
3846 for (num = 0; num < o->length; num++) {
3847 if (!isdigit(o->data[num])) {
3851 num = atoi(o->data);
3857 #define parse_stream(pstring, input, end_trigger) \
3858 parse_stream(input, end_trigger)
3860 static struct pipe *parse_stream(char **pstring,
3861 struct in_str *input,
3863 static void parse_and_run_string(const char *s);
3865 #if ENABLE_HUSH_TICK
3866 static FILE *generate_stream_from_string(const char *s)
3869 int pid, channel[2];
3872 pid = BB_MMU ? fork() : vfork();
3874 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
3876 if (pid == 0) { /* child */
3878 die_sleep = 0; /* do not restore tty pgrp on xfunc death */
3880 /* Process substitution is not considered to be usual
3881 * 'command execution'.
3882 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
3889 close(channel[0]); /* NB: close _first_, then move fd! */
3890 xmove_fd(channel[1], 1);
3891 /* Prevent it from trying to handle ctrl-z etc */
3892 USE_HUSH_JOB(G.run_list_level = 1;)
3894 reset_traps_to_defaults();
3895 parse_and_run_string(s);
3896 _exit(G.last_return_code);
3898 /* We re-execute after vfork on NOMMU. This makes this script safe:
3899 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >BIG
3900 * huge=`cat BIG` # was blocking here forever
3903 re_execute_shell(s);
3909 die_sleep = -1; /* restore tty pgrp on xfunc death */
3911 clean_up_after_re_execute();
3913 pf = fdopen(channel[0], "r");
3917 /* Return code is exit status of the process that is run. */
3918 static int process_command_subs(o_string *dest, const char *s)
3921 struct in_str pipe_str;
3924 pf = generate_stream_from_string(s);
3927 close_on_exec_on(fileno(pf));
3929 /* Now send results of command back into original context */
3930 setup_file_in_str(&pipe_str, pf);
3932 while ((ch = i_getch(&pipe_str)) != EOF) {
3938 o_addchr(dest, '\n');
3941 o_addQchr(dest, ch);
3944 debug_printf("done reading from pipe, pclose()ing\n");
3945 /* Note: we got EOF, and we just close the read end of the pipe.
3946 * We do not wait for the `cmd` child to terminate. bash and ash do.
3948 * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec
3949 * `false`; echo $? - bash outputs "1"
3952 debug_printf("closed FILE from child. return 0\n");
3957 static int parse_group(o_string *dest, struct parse_context *ctx,
3958 struct in_str *input, int ch)
3960 /* dest contains characters seen prior to ( or {.
3961 * Typically it's empty, but for function defs,
3962 * it contains function name (without '()'). */
3963 struct pipe *pipe_list;
3965 struct command *command = ctx->command;
3967 debug_printf_parse("parse_group entered\n");
3968 #if ENABLE_HUSH_FUNCTIONS
3969 if (ch == 'F') { /* function definition? */
3970 bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
3971 //command->fname = dest->data;
3972 command->grp_type = GRP_FUNCTION;
3973 //TODO: review every o_reset() location... do they handle all o_string fields correctly?
3974 memset(dest, 0, sizeof(*dest));
3977 if (command->argv /* word [word](... */
3978 || dest->length /* word(... */
3979 || dest->nonnull /* ""(... */
3982 debug_printf_parse("parse_group return 1: "
3983 "syntax error, groups and arglists don't mix\n");
3989 command->grp_type = GRP_SUBSHELL;
3993 char *as_string = NULL;
3995 pipe_list = parse_stream(&as_string, input, endch);
3998 o_addstr(&ctx->as_string, as_string);
4000 /* empty ()/{} or parse error? */
4001 if (!pipe_list || pipe_list == ERR_PTR) {
4006 debug_printf_parse("parse_group return 1: "
4007 "parse_stream returned %p\n", pipe_list);
4010 command->group = pipe_list;
4012 as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
4013 command->group_as_string = as_string;
4014 debug_printf_parse("end of group, remembering as:'%s'\n",
4015 command->group_as_string);
4018 debug_printf_parse("parse_group return 0\n");
4020 /* command remains "open", available for possible redirects */
4023 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
4024 /* Subroutines for copying $(...) and `...` things */
4025 static void add_till_backquote(o_string *dest, struct in_str *input);
4027 static void add_till_single_quote(o_string *dest, struct in_str *input)
4030 int ch = i_getch(input);
4038 /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
4039 static void add_till_double_quote(o_string *dest, struct in_str *input)
4042 int ch = i_getch(input);
4045 if (ch == '\\') { /* \x. Copy both chars. */
4047 ch = i_getch(input);
4053 add_till_backquote(dest, input);
4057 //if (ch == '$') ...
4060 /* Process `cmd` - copy contents until "`" is seen. Complicated by
4062 * "Within the backquoted style of command substitution, backslash
4063 * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
4064 * The search for the matching backquote shall be satisfied by the first
4065 * backquote found without a preceding backslash; during this search,
4066 * if a non-escaped backquote is encountered within a shell comment,
4067 * a here-document, an embedded command substitution of the $(command)
4068 * form, or a quoted string, undefined results occur. A single-quoted
4069 * or double-quoted string that begins, but does not end, within the
4070 * "`...`" sequence produces undefined results."
4072 * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
4074 static void add_till_backquote(o_string *dest, struct in_str *input)
4077 int ch = i_getch(input);
4080 if (ch == '\\') { /* \x. Copy both chars unless it is \` */
4081 int ch2 = i_getch(input);
4082 if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
4091 /* Process $(cmd) - copy contents until ")" is seen. Complicated by
4092 * quoting and nested ()s.
4093 * "With the $(command) style of command substitution, all characters
4094 * following the open parenthesis to the matching closing parenthesis
4095 * constitute the command. Any valid shell script can be used for command,
4096 * except a script consisting solely of redirections which produces
4097 * unspecified results."
4099 * echo $(echo '(TEST)' BEST) (TEST) BEST
4100 * echo $(echo 'TEST)' BEST) TEST) BEST
4101 * echo $(echo \(\(TEST\) BEST) ((TEST) BEST
4103 static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
4107 int ch = i_getch(input);
4116 if (i_peek(input) == ')') {
4124 add_till_single_quote(dest, input);
4129 add_till_double_quote(dest, input);
4133 if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */
4134 ch = i_getch(input);
4142 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
4144 /* Return code: 0 for OK, 1 for syntax error */
4146 #define handle_dollar(as_string, dest, input) \
4147 handle_dollar(dest, input)
4149 static int handle_dollar(o_string *as_string,
4151 struct in_str *input)
4154 int ch = i_peek(input); /* first character after the $ */
4155 unsigned char quote_mask = dest->o_escape ? 0x80 : 0;
4157 debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
4159 ch = i_getch(input);
4161 if (as_string) o_addchr(as_string, ch);
4164 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4166 debug_printf_parse(": '%c'\n", ch);
4167 o_addchr(dest, ch | quote_mask);
4170 if (!isalnum(ch) && ch != '_')
4172 ch = i_getch(input);
4174 if (as_string) o_addchr(as_string, ch);
4177 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4178 } else if (isdigit(ch)) {
4180 ch = i_getch(input);
4182 if (as_string) o_addchr(as_string, ch);
4184 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4185 debug_printf_parse(": '%c'\n", ch);
4186 o_addchr(dest, ch | quote_mask);
4187 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4188 } else switch (ch) {
4190 case '!': /* last bg pid */
4191 case '?': /* last exit code */
4192 case '#': /* number of args */
4193 case '*': /* args */
4194 case '@': /* args */
4195 goto make_one_char_var;
4197 bool first_char, all_digits;
4199 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4200 ch = i_getch(input);
4202 if (as_string) o_addchr(as_string, ch);
4204 /* XXX maybe someone will try to escape the '}' */
4209 ch = i_getch(input);
4211 if (as_string) o_addchr(as_string, ch);
4218 /* ${#var}: length of var contents */
4220 else if (isdigit(ch)) {
4227 && ( (all_digits && !isdigit(ch))
4228 || (!all_digits && !isalnum(ch) && ch != '_')
4231 /* handle parameter expansions
4232 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
4237 case ':': /* null modifier */
4238 if (expansion == 0) {
4239 debug_printf_parse(": null modifier\n");
4244 #if 0 /* not implemented yet :( */
4245 case '#': /* remove prefix */
4246 case '%': /* remove suffix */
4247 if (expansion == 0) {
4248 debug_printf_parse(": remove suffix/prefix\n");
4254 case '-': /* default value */
4255 case '=': /* assign default */
4256 case '+': /* alternative */
4257 case '?': /* error indicate */
4258 debug_printf_parse(": parameter expansion\n");
4263 syntax("unterminated ${name}");
4264 debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
4269 debug_printf_parse(": '%c'\n", ch);
4270 o_addchr(dest, ch | quote_mask);
4274 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4277 #if (ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_TICK)
4282 ch = i_getch(input);
4284 if (as_string) o_addchr(as_string, ch);
4286 # if ENABLE_SH_MATH_SUPPORT
4287 if (i_peek(input) == '(') {
4288 ch = i_getch(input);
4290 if (as_string) o_addchr(as_string, ch);
4292 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4293 o_addchr(dest, /*quote_mask |*/ '+');
4297 add_till_closing_paren(dest, input, true);
4300 o_addstr(as_string, dest->data + pos);
4301 o_addchr(as_string, ')');
4302 o_addchr(as_string, ')');
4305 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4309 # if ENABLE_HUSH_TICK
4310 //int pos = dest->length;
4311 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4312 o_addchr(dest, quote_mask | '`');
4316 add_till_closing_paren(dest, input, false);
4319 o_addstr(as_string, dest->data + pos);
4320 o_addchr(as_string, '`');
4323 //debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
4324 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4330 ch = i_getch(input);
4332 if (as_string) o_addchr(as_string, ch);
4335 if (isalnum(ch)) { /* it's $_name or $_123 */
4341 /* $_ Shell or shell script name; or last cmd name */
4342 /* $- Option flags set by set builtin or shell options (-i etc) */
4344 o_addQchr(dest, '$');
4346 debug_printf_parse("handle_dollar return 0\n");
4351 #define parse_stream_dquoted(as_string, dest, input, dquote_end) \
4352 parse_stream_dquoted(dest, input, dquote_end)
4354 static int parse_stream_dquoted(o_string *as_string,
4356 struct in_str *input,
4363 ch = i_getch(input);
4365 if (as_string && ch != EOF)
4366 o_addchr(as_string, ch);
4368 if (ch == dquote_end) { /* may be only '"' or EOF */
4370 if (dest->o_assignment == NOT_ASSIGNMENT)
4371 dest->o_escape ^= 1;
4372 debug_printf_parse("parse_stream_dquoted return 0\n");
4376 syntax("unterminated \"");
4377 debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n");
4382 next = i_peek(input);
4384 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4385 ch, ch, dest->o_escape);
4389 debug_printf_parse("parse_stream_dquoted return 1: \\<eof>\n");
4393 * "The backslash retains its special meaning [in "..."]
4394 * only when followed by one of the following characters:
4395 * $, `, ", \, or <newline>. A double quote may be quoted
4396 * within double quotes by preceding it with a backslash.
4397 * If enabled, history expansion will be performed unless
4398 * an ! appearing in double quotes is escaped using
4399 * a backslash. The backslash preceding the ! is not removed."
4401 if (strchr("$`\"\\", next) != NULL) {
4402 o_addqchr(dest, i_getch(input));
4404 o_addqchr(dest, '\\');
4409 if (handle_dollar(as_string, dest, input) != 0) {
4410 debug_printf_parse("parse_stream_dquoted return 1: "
4411 "handle_dollar returned non-0\n");
4416 #if ENABLE_HUSH_TICK
4418 //int pos = dest->length;
4419 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4420 o_addchr(dest, 0x80 | '`');
4421 add_till_backquote(dest, input);
4422 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4423 //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
4427 o_addQchr(dest, ch);
4429 && (dest->o_assignment == MAYBE_ASSIGNMENT
4430 || dest->o_assignment == WORD_IS_KEYWORD)
4431 && is_assignment(dest->data)
4433 dest->o_assignment = DEFINITELY_ASSIGNMENT;
4439 * Scan input until EOF or end_trigger char.
4440 * Return a list of pipes to execute, or NULL on EOF
4441 * or if end_trigger character is met.
4442 * On syntax error, exit is shell is not interactive,
4443 * reset parsing machinery and start parsing anew,
4444 * or return ERR_PTR.
4446 static struct pipe *parse_stream(char **pstring,
4447 struct in_str *input,
4450 struct parse_context ctx;
4451 o_string dest = NULL_O_STRING;
4454 /* Double-quote state is handled in the state variable is_in_dquote.
4455 * A single-quote triggers a bypass of the main loop until its mate is
4456 * found. When recursing, quote state is passed in via dest->o_escape.
4458 debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
4459 end_trigger ? : 'X');
4461 G.ifs = get_local_var_value("IFS");
4466 #if ENABLE_HUSH_INTERACTIVE
4467 input->promptmode = 0; /* PS1 */
4469 /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */
4470 initialize_context(&ctx);
4474 const char *is_special;
4478 redir_type redir_style;
4481 if (parse_stream_dquoted(&ctx.as_string, &dest, input, '"')) {
4484 /* We reached closing '"' */
4487 ch = i_getch(input);
4488 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4489 ch, ch, dest.o_escape);
4492 if (done_word(&dest, &ctx)) {
4496 done_pipe(&ctx, PIPE_SEQ);
4498 /* If we got nothing... */
4499 // TODO: test script consisting of just "&"
4500 if (pi->num_cmds == 0
4501 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
4503 free_pipe_list(pi, 0);
4506 debug_printf_parse("parse_stream return %p\n", pi);
4508 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4510 *pstring = ctx.as_string.data;
4512 o_free_unsafe(&ctx.as_string);
4517 o_addchr(&ctx.as_string, ch);
4519 is_ifs = strchr(G.ifs, ch);
4520 is_special = strchr("<>;&|(){}#'" /* special outside of "str" */
4521 "\\$\"" USE_HUSH_TICK("`") /* always special */
4524 if (!is_special && !is_ifs) { /* ordinary char */
4525 o_addQchr(&dest, ch);
4526 if ((dest.o_assignment == MAYBE_ASSIGNMENT
4527 || dest.o_assignment == WORD_IS_KEYWORD)
4529 && is_assignment(dest.data)
4531 dest.o_assignment = DEFINITELY_ASSIGNMENT;
4537 if (done_word(&dest, &ctx)) {
4541 #if ENABLE_HUSH_CASE
4542 /* "case ... in <newline> word) ..." -
4543 * newlines are ignored (but ';' wouldn't be) */
4544 if (ctx.command->argv == NULL
4545 && ctx.ctx_res_w == RES_MATCH
4550 /* Treat newline as a command separator. */
4551 done_pipe(&ctx, PIPE_SEQ);
4552 dest.o_assignment = MAYBE_ASSIGNMENT;
4554 /* note: if (is_ifs) continue;
4555 * will still trigger for us */
4558 if (end_trigger && end_trigger == ch) {
4559 //TODO: disallow "{ cmd }" without semicolon
4560 if (done_word(&dest, &ctx)) {
4563 done_pipe(&ctx, PIPE_SEQ);
4564 dest.o_assignment = MAYBE_ASSIGNMENT;
4565 /* Do we sit outside of any if's, loops or case's? */
4567 IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
4569 debug_printf_parse("parse_stream return %p: "
4570 "end_trigger char found\n",
4574 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4576 *pstring = ctx.as_string.data;
4578 o_free_unsafe(&ctx.as_string);
4580 return ctx.list_head;
4586 if (dest.o_assignment == MAYBE_ASSIGNMENT) {
4587 /* ch is a special char and thus this word
4588 * cannot be an assignment */
4589 dest.o_assignment = NOT_ASSIGNMENT;
4594 next = i_peek(input);
4599 if (dest.length == 0) {
4602 if (ch == EOF || ch == '\n')
4605 /* note: we do not add it to &ctx.as_string */
4608 //TODO: go back one char?
4609 o_addchr(&ctx.as_string, '\n');
4612 o_addQchr(&dest, ch);
4620 o_addchr(&dest, '\\');
4621 ch = i_getch(input);
4622 o_addchr(&dest, ch);
4624 o_addchr(&ctx.as_string, ch);
4628 if (handle_dollar(&ctx.as_string, &dest, input) != 0) {
4629 debug_printf_parse("parse_stream parse error: "
4630 "handle_dollar returned non-0\n");
4637 ch = i_getch(input);
4639 syntax("unterminated '");
4643 o_addchr(&ctx.as_string, ch);
4647 if (dest.o_assignment == NOT_ASSIGNMENT)
4648 o_addqchr(&dest, ch);
4650 o_addchr(&dest, ch);
4655 is_in_dquote ^= 1; /* invert */
4656 if (dest.o_assignment == NOT_ASSIGNMENT)
4659 #if ENABLE_HUSH_TICK
4661 //int pos = dest.length;
4662 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4663 o_addchr(&dest, '`');
4664 add_till_backquote(&dest, input);
4665 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4666 //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos);
4671 redir_fd = redirect_opt_num(&dest);
4672 if (done_word(&dest, &ctx)) {
4675 redir_style = REDIRECT_OVERWRITE;
4677 redir_style = REDIRECT_APPEND;
4678 ch = i_getch(input);
4680 o_addchr(&ctx.as_string, ch);
4684 else if (next == '(') {
4685 syntax(">(process) not supported");
4689 setup_redirect(&ctx, redir_fd, redir_style, input);
4692 redir_fd = redirect_opt_num(&dest);
4693 if (done_word(&dest, &ctx)) {
4696 redir_style = REDIRECT_INPUT;
4698 redir_style = REDIRECT_HEREIS;
4699 ch = i_getch(input);
4701 o_addchr(&ctx.as_string, ch);
4703 } else if (next == '>') {
4704 redir_style = REDIRECT_IO;
4705 ch = i_getch(input);
4707 o_addchr(&ctx.as_string, ch);
4711 else if (next == '(') {
4712 syntax("<(process) not supported");
4716 setup_redirect(&ctx, redir_fd, redir_style, input);
4719 #if ENABLE_HUSH_CASE
4722 if (done_word(&dest, &ctx)) {
4725 done_pipe(&ctx, PIPE_SEQ);
4726 #if ENABLE_HUSH_CASE
4727 /* Eat multiple semicolons, detect
4728 * whether it means something special */
4733 ch = i_getch(input);
4735 o_addchr(&ctx.as_string, ch);
4737 if (ctx.ctx_res_w == RES_CASEI) {
4738 ctx.ctx_dsemicolon = 1;
4739 ctx.ctx_res_w = RES_MATCH;
4745 /* We just finished a cmd. New one may start
4746 * with an assignment */
4747 dest.o_assignment = MAYBE_ASSIGNMENT;
4750 if (done_word(&dest, &ctx)) {
4754 ch = i_getch(input);
4756 o_addchr(&ctx.as_string, ch);
4758 done_pipe(&ctx, PIPE_AND);
4760 done_pipe(&ctx, PIPE_BG);
4764 if (done_word(&dest, &ctx)) {
4767 #if ENABLE_HUSH_CASE
4768 if (ctx.ctx_res_w == RES_MATCH)
4769 break; /* we are in case's "word | word)" */
4771 if (next == '|') { /* || */
4772 ch = i_getch(input);
4774 o_addchr(&ctx.as_string, ch);
4776 done_pipe(&ctx, PIPE_OR);
4778 /* we could pick up a file descriptor choice here
4779 * with redirect_opt_num(), but bash doesn't do it.
4780 * "echo foo 2| cat" yields "foo 2". */
4785 #if ENABLE_HUSH_CASE
4786 /* "case... in [(]word)..." - skip '(' */
4787 if (ctx.ctx_res_w == RES_MATCH
4788 && ctx.command->argv == NULL /* not (word|(... */
4789 && dest.length == 0 /* not word(... */
4790 && dest.nonnull == 0 /* not ""(... */
4795 #if ENABLE_HUSH_FUNCTIONS
4796 if (dest.length != 0 /* not just () but word() */
4797 && dest.nonnull == 0 /* not a"b"c() */
4798 && ctx.command->argv == NULL /* it's the first word */
4799 //TODO: "func ( ) {...}" - note spaces - is valid format too in bash
4800 && i_peek(input) == ')'
4801 && !match_reserved_word(&dest)
4803 bb_error_msg("seems like a function definition");
4805 //if !BB_MMU o_addchr(&ctx.as_string...
4807 //TODO: do it properly.
4808 ch = i_getch(input);
4809 } while (ch == ' ' || ch == '\n');
4811 syntax("was expecting {");
4814 ch = 'F'; /* magic value */
4818 if (parse_group(&dest, &ctx, input, ch) != 0) {
4823 #if ENABLE_HUSH_CASE
4824 if (ctx.ctx_res_w == RES_MATCH)
4828 /* proper use of this character is caught by end_trigger:
4829 * if we see {, we call parse_group(..., end_trigger='}')
4830 * and it will match } earlier (not here). */
4831 syntax("unexpected } or )");
4835 bb_error_msg_and_die("BUG: unexpected %c\n", ch);
4841 struct parse_context *pctx;
4842 IF_HAS_KEYWORDS(struct parse_context *p2;)
4844 /* Clean up allocated tree.
4845 * Samples for finding leaks on syntax error recovery path.
4846 * Run them from interactive shell, watch pmap `pidof hush`.
4847 * while if false; then false; fi do break; done
4849 * while if false; then false; fi; do break; fi
4850 * Samples to catch leaks at execution:
4851 * while if (true | {true;}); then echo ok; fi; do break; done
4852 * while if (true | {true;}); then echo ok; fi; do (if echo ok; break; then :; fi) | cat; break; done
4856 /* Update pipe/command counts,
4857 * otherwise freeing may miss some */
4858 done_pipe(pctx, PIPE_SEQ);
4859 debug_printf_clean("freeing list %p from ctx %p\n",
4860 pctx->list_head, pctx);
4861 debug_print_tree(pctx->list_head, 0);
4862 free_pipe_list(pctx->list_head, 0);
4863 debug_printf_clean("freed list %p\n", pctx->list_head);
4865 o_free_unsafe(&pctx->as_string);
4867 IF_HAS_KEYWORDS(p2 = pctx->stack;)
4871 IF_HAS_KEYWORDS(pctx = p2;)
4872 } while (HAS_KEYWORDS && pctx);
4873 /* Free text, clear all dest fields */
4875 /* If we are not in top-level parse, we return,
4876 * our caller will propagate error.
4878 if (end_trigger != ';') {
4885 /* Discard cached input, force prompt */
4887 USE_HUSH_INTERACTIVE(input->promptme = 1;)
4892 /* Executing from string: eval, sh -c '...'
4893 * or from file: /etc/profile, . file, sh <script>, sh (intereactive)
4894 * end_trigger controls how often we stop parsing
4895 * NUL: parse all, execute, return
4896 * ';': parse till ';' or newline, execute, repeat till EOF
4898 static void parse_and_run_stream(struct in_str *inp, int end_trigger)
4901 struct pipe *pipe_list;
4903 pipe_list = parse_stream(NULL, inp, end_trigger);
4904 if (!pipe_list) /* EOF */
4906 debug_print_tree(pipe_list, 0);
4907 debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
4908 run_and_free_list(pipe_list);
4912 static void parse_and_run_string(const char *s)
4914 struct in_str input;
4915 setup_string_in_str(&input, s);
4916 parse_and_run_stream(&input, '\0');
4919 static void parse_and_run_file(FILE *f)
4921 struct in_str input;
4922 setup_file_in_str(&input, f);
4923 parse_and_run_stream(&input, ';');
4926 /* Called a few times only (or even once if "sh -c") */
4927 static void block_signals(int second_time)
4932 mask = (1 << SIGQUIT);
4933 if (G_interactive_fd) {
4937 //TODO | (1 << SIGHUP)
4939 | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
4944 G.non_DFL_mask = mask;
4947 sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
4951 sigaddset(&G.blocked_set, sig);
4955 sigdelset(&G.blocked_set, SIGCHLD);
4957 sigprocmask(SIG_SETMASK, &G.blocked_set,
4958 second_time ? NULL : &G.inherited_set);
4959 /* POSIX allows shell to re-enable SIGCHLD
4960 * even if it was SIG_IGN on entry */
4961 // G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
4963 signal(SIGCHLD, SIG_DFL); // SIGCHLD_handler);
4968 static void maybe_set_to_sigexit(int sig)
4970 void (*handler)(int);
4971 /* non_DFL_mask'ed signals are, well, masked,
4972 * no need to set handler for them.
4974 if (!((G.non_DFL_mask >> sig) & 1)) {
4975 handler = signal(sig, sigexit);
4976 if (handler == SIG_IGN) /* oops... restore back to IGN! */
4977 signal(sig, handler);
4980 /* Set handlers to restore tty pgrp and exit */
4981 static void set_fatal_handlers(void)
4983 /* We _must_ restore tty pgrp on fatal signals */
4985 maybe_set_to_sigexit(SIGILL );
4986 maybe_set_to_sigexit(SIGFPE );
4987 maybe_set_to_sigexit(SIGBUS );
4988 maybe_set_to_sigexit(SIGSEGV);
4989 maybe_set_to_sigexit(SIGTRAP);
4990 } /* else: hush is perfect. what SEGV? */
4991 maybe_set_to_sigexit(SIGABRT);
4992 /* bash 3.2 seems to handle these just like 'fatal' ones */
4993 maybe_set_to_sigexit(SIGPIPE);
4994 maybe_set_to_sigexit(SIGALRM);
4995 //TODO: disable and move down when proper SIGHUP handling is added
4996 maybe_set_to_sigexit(SIGHUP );
4997 /* if we are interactive, [SIGHUP,] SIGTERM and SIGINT are masked.
4998 * if we aren't interactive... but in this case
4999 * we never want to restore pgrp on exit, and this fn is not called */
5000 /*maybe_set_to_sigexit(SIGTERM);*/
5001 /*maybe_set_to_sigexit(SIGINT );*/
5005 static int set_mode(const char cstate, const char mode)
5007 int state = (cstate == '-' ? 1 : 0);
5009 case 'n': G.fake_mode = state; break;
5010 case 'x': /*G.debug_mode = state;*/ break;
5011 default: return EXIT_FAILURE;
5013 return EXIT_SUCCESS;
5016 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5017 int hush_main(int argc, char **argv)
5019 static const struct variable const_shell_ver = {
5021 .varstr = (char*)hush_version_str,
5022 .max_len = 1, /* 0 can provoke free(name) */
5026 int signal_mask_is_inited = 0;
5029 struct variable *cur_var;
5032 if (EXIT_SUCCESS) /* if EXIT_SUCCESS == 0, is already done */
5033 G.last_return_code = EXIT_SUCCESS;
5035 G.argv0_for_re_execing = argv[0];
5037 /* Deal with HUSH_VERSION */
5038 G.shell_ver = const_shell_ver; /* copying struct here */
5039 G.top_var = &G.shell_ver;
5040 debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
5041 unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
5042 /* Initialize our shell local variables with the values
5043 * currently living in the environment */
5044 cur_var = G.top_var;
5047 char *value = strchr(*e, '=');
5048 if (value) { /* paranoia */
5049 cur_var->next = xzalloc(sizeof(*cur_var));
5050 cur_var = cur_var->next;
5051 cur_var->varstr = *e;
5052 cur_var->max_len = strlen(*e);
5053 cur_var->flg_export = 1;
5057 debug_printf_env("putenv '%s'\n", hush_version_str);
5058 putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
5059 #if ENABLE_FEATURE_EDITING
5060 G.line_input_state = new_line_input_t(FOR_SHELL);
5062 G.global_argc = argc;
5063 G.global_argv = argv;
5064 /* Initialize some more globals to non-zero values */
5066 #if ENABLE_HUSH_INTERACTIVE
5067 if (ENABLE_FEATURE_EDITING)
5068 cmdedit_set_initial_prompt();
5072 /* Shell is non-interactive at first. We need to call
5073 * block_signals(0) if we are going to execute "sh <script>",
5074 * "sh -c <cmds>" or login shell's /etc/profile and friends.
5075 * If we later decide that we are interactive, we run block_signals(0)
5076 * (or re-run block_signals(1) if we ran block_signals(0) before)
5077 * in order to intercept (more) signals.
5081 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
5083 opt = getopt(argc, argv, "c:xins"
5093 G.root_pid = getpid();
5094 G.global_argv = argv + optind;
5095 if (!argv[optind]) {
5096 /* -c 'script' (no params): prevent empty $0 */
5097 *--G.global_argv = argv[0];
5099 } /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
5100 G.global_argc = argc - optind;
5101 block_signals(0); /* 0: called 1st time */
5102 parse_and_run_string(optarg);
5105 /* Well, we cannot just declare interactiveness,
5106 * we have to have some stuff (ctty, etc) */
5107 /* G_interactive_fd++; */
5110 /* "-s" means "read from stdin", but this is how we always
5111 * operate, so simply do nothing here. */
5115 G.root_pid = xatoi_u(optarg);
5118 G.last_bg_pid = xatoi_u(optarg);
5121 G.last_return_code = xatoi_u(optarg);
5123 # if ENABLE_HUSH_LOOPS
5125 G.depth_of_loop = xatoi_u(optarg);
5130 set_local_var(xstrdup(optarg), 0, opt == 'R');
5135 if (!set_mode('-', opt))
5139 fprintf(stderr, "Usage: sh [FILE]...\n"
5140 " or: sh -c command [args]...\n\n");
5146 } /* option parsing loop */
5149 G.root_pid = getpid();
5151 /* If we are login shell... */
5152 if (argv[0] && argv[0][0] == '-') {
5154 /* XXX what should argv be while sourcing /etc/profile? */
5155 debug_printf("sourcing /etc/profile\n");
5156 input = fopen_for_read("/etc/profile");
5157 if (input != NULL) {
5158 close_on_exec_on(fileno(input));
5159 block_signals(0); /* 0: called 1st time */
5160 signal_mask_is_inited = 1;
5161 parse_and_run_file(input);
5164 /* bash: after sourcing /etc/profile,
5165 * tries to source (in the given order):
5166 * ~/.bash_profile, ~/.bash_login, ~/.profile,
5167 * stopping of first found. --noprofile turns this off.
5168 * bash also sources ~/.bash_logout on exit.
5169 * If called as sh, skips .bash_XXX files.
5176 * "bash <script>" (which is never interactive (unless -i?))
5177 * sources $BASH_ENV here (without scanning $PATH).
5178 * If called as sh, does the same but with $ENV.
5180 debug_printf("running script '%s'\n", argv[optind]);
5181 G.global_argv = argv + optind;
5182 G.global_argc = argc - optind;
5183 input = xfopen_for_read(argv[optind]);
5184 close_on_exec_on(fileno(input));
5185 if (!signal_mask_is_inited)
5186 block_signals(0); /* 0: called 1st time */
5187 parse_and_run_file(input);
5188 #if ENABLE_FEATURE_CLEAN_UP
5194 /* Up to here, shell was non-interactive. Now it may become one.
5195 * NB: don't forget to (re)run block_signals(0/1) as needed.
5198 /* A shell is interactive if the '-i' flag was given, or if all of
5199 * the following conditions are met:
5201 * no arguments remaining or the -s flag given
5202 * standard input is a terminal
5203 * standard output is a terminal
5204 * Refer to Posix.2, the description of the 'sh' utility.
5207 if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
5208 G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
5209 debug_printf("saved_tty_pgrp:%d\n", G.saved_tty_pgrp);
5210 //TODO: "interactive" and "have job control" are two different things.
5211 //If tcgetpgrp fails here, "have job control" is false, but "interactive"
5212 //should stay on! Currently, we mix these into one.
5213 if (G.saved_tty_pgrp >= 0) {
5214 /* try to dup stdin to high fd#, >= 255 */
5215 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5216 if (G_interactive_fd < 0) {
5217 /* try to dup to any fd */
5218 G_interactive_fd = dup(STDIN_FILENO);
5219 if (G_interactive_fd < 0)
5221 G_interactive_fd = 0;
5223 // TODO: track & disallow any attempts of user
5224 // to (inadvertently) close/redirect it
5227 debug_printf("interactive_fd:%d\n", G_interactive_fd);
5228 if (G_interactive_fd) {
5231 /* We are indeed interactive shell, and we will perform
5232 * job control. Setting up for that. */
5234 close_on_exec_on(G_interactive_fd);
5235 /* If we were run as 'hush &', sleep until we are
5236 * in the foreground (tty pgrp == our pgrp).
5237 * If we get started under a job aware app (like bash),
5238 * make sure we are now in charge so we don't fight over
5239 * who gets the foreground */
5241 shell_pgrp = getpgrp();
5242 G.saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
5243 if (G.saved_tty_pgrp == shell_pgrp)
5245 /* send TTIN to ourself (should stop us) */
5246 kill(- shell_pgrp, SIGTTIN);
5248 /* Block some signals */
5249 block_signals(signal_mask_is_inited);
5250 /* Set other signals to restore saved_tty_pgrp */
5251 set_fatal_handlers();
5252 /* Put ourselves in our own process group */
5253 bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
5254 /* Grab control of the terminal */
5255 tcsetpgrp(G_interactive_fd, getpid());
5256 /* -1 is special - makes xfuncs longjmp, not exit
5257 * (we reset die_sleep = 0 whereever we [v]fork) */
5259 if (setjmp(die_jmp)) {
5260 /* xfunc has failed! die die die */
5261 hush_exit(xfunc_error_retval);
5263 } else if (!signal_mask_is_inited) {
5264 block_signals(0); /* 0: called 1st time */
5265 } /* else: block_signals(0) was done before */
5266 #elif ENABLE_HUSH_INTERACTIVE
5267 /* No job control compiled in, only prompt/line editing */
5268 if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
5269 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5270 if (G_interactive_fd < 0) {
5271 /* try to dup to any fd */
5272 G_interactive_fd = dup(STDIN_FILENO);
5273 if (G_interactive_fd < 0)
5275 G_interactive_fd = 0;
5278 if (G_interactive_fd) {
5279 close_on_exec_on(G_interactive_fd);
5280 block_signals(signal_mask_is_inited);
5281 } else if (!signal_mask_is_inited) {
5285 /* We have interactiveness code disabled */
5286 if (!signal_mask_is_inited) {
5291 * if interactive but not a login shell, sources ~/.bashrc
5292 * (--norc turns this off, --rcfile <file> overrides)
5295 if (!ENABLE_FEATURE_SH_EXTRA_QUIET && G_interactive_fd) {
5296 printf("\n\n%s hush - the humble shell\n", bb_banner);
5297 printf("Enter 'help' for a list of built-in commands.\n\n");
5300 parse_and_run_file(stdin);
5303 #if ENABLE_FEATURE_CLEAN_UP
5304 if (G.cwd != bb_msg_unknown)
5306 cur_var = G.top_var->next;
5308 struct variable *tmp = cur_var;
5309 if (!cur_var->max_len)
5310 free(cur_var->varstr);
5311 cur_var = cur_var->next;
5315 hush_exit(G.last_return_code);
5320 int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5321 int lash_main(int argc, char **argv)
5323 //bb_error_msg("lash is deprecated, please use hush instead");
5324 return hush_main(argc, argv);
5332 static int builtin_trap(char **argv)
5339 G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
5343 /* No args: print all trapped. This isn't 100% correct as we
5344 * should be escaping the cmd so that it can be pasted back in
5346 for (i = 0; i < NSIG; ++i)
5348 printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
5349 return EXIT_SUCCESS;
5354 /* If first arg is decimal: reset all specified signals */
5355 sig = bb_strtou(*argv, NULL, 10);
5361 sig = get_signum(*argv++);
5362 if (sig < 0 || sig >= NSIG) {
5364 /* Mimic bash message exactly */
5365 bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
5370 G.traps[sig] = xstrdup(new_cmd);
5372 debug_printf("trap: setting SIG%s (%i) to '%s'",
5373 get_signame(sig), sig, G.traps[sig]);
5375 /* There is no signal for 0 (EXIT) */
5380 sigaddset(&G.blocked_set, sig);
5382 /* There was a trap handler, we are removing it
5383 * (if sig has non-DFL handling,
5384 * we don't need to do anything) */
5385 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
5387 sigdelset(&G.blocked_set, sig);
5389 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5394 /* First arg is "-": reset all specified to default */
5395 /* First arg is "": ignore all specified */
5396 /* Everything else: execute first arg upon signal */
5398 bb_error_msg("trap: invalid arguments");
5399 return EXIT_FAILURE;
5401 if (NOT_LONE_DASH(*argv))
5407 static int builtin_true(char **argv UNUSED_PARAM)
5412 static int builtin_test(char **argv)
5419 return test_main(argc, argv - argc);
5422 static int builtin_echo(char **argv)
5429 return echo_main(argc, argv - argc);
5432 static int builtin_eval(char **argv)
5434 int rcode = EXIT_SUCCESS;
5437 char *str = expand_strvec_to_string(argv);
5439 * eval "echo Hi; done" ("done" is syntax error):
5440 * "echo Hi" will not execute too.
5442 parse_and_run_string(str);
5444 rcode = G.last_return_code;
5449 static int builtin_cd(char **argv)
5451 const char *newdir = argv[1];
5452 if (newdir == NULL) {
5453 /* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
5454 * bash says "bash: cd: HOME not set" and does nothing (exitcode 1)
5456 newdir = getenv("HOME") ? : "/";
5458 if (chdir(newdir)) {
5459 /* Mimic bash message exactly */
5460 bb_perror_msg("cd: %s", newdir);
5461 return EXIT_FAILURE;
5464 return EXIT_SUCCESS;
5467 static int builtin_exec(char **argv)
5469 if (*++argv == NULL)
5470 return EXIT_SUCCESS; /* bash does this */
5475 // FIXME: if exec fails, bash does NOT exit! We do...
5476 pseudo_exec_argv(&dummy, argv, 0, NULL);
5481 static int builtin_exit(char **argv)
5483 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
5484 //puts("exit"); /* bash does it */
5485 // TODO: warn if we have background jobs: "There are stopped jobs"
5486 // On second consecutive 'exit', exit anyway.
5487 if (*++argv == NULL)
5488 hush_exit(G.last_return_code);
5489 /* mimic bash: exit 123abc == exit 255 + error msg */
5490 xfunc_error_retval = 255;
5491 /* bash: exit -2 == exit 254, no error msg */
5492 hush_exit(xatoi(*argv) & 0xff);
5495 static int builtin_export(char **argv)
5497 if (*++argv == NULL) {
5499 // ash emits: export VAR='VAL'
5500 // bash: declare -x VAR="VAL"
5501 // (both also escape as needed (quotes, $, etc))
5506 return EXIT_SUCCESS;
5513 value = strchr(name, '=');
5515 /* They are exporting something without a =VALUE */
5516 struct variable *var;
5518 var = get_local_var(name);
5520 var->flg_export = 1;
5521 debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
5522 putenv(var->varstr);
5524 /* bash does not return an error when trying to export
5525 * an undefined variable. Do likewise. */
5528 set_local_var(xstrdup(name), 1, 0);
5531 return EXIT_SUCCESS;
5535 /* built-in 'fg' and 'bg' handler */
5536 static int builtin_fg_bg(char **argv)
5541 if (!G_interactive_fd)
5542 return EXIT_FAILURE;
5543 /* If they gave us no args, assume they want the last backgrounded task */
5545 for (pi = G.job_list; pi; pi = pi->next) {
5546 if (pi->jobid == G.last_jobid) {
5550 bb_error_msg("%s: no current job", argv[0]);
5551 return EXIT_FAILURE;
5553 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
5554 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
5555 return EXIT_FAILURE;
5557 for (pi = G.job_list; pi; pi = pi->next) {
5558 if (pi->jobid == jobnum) {
5562 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
5563 return EXIT_FAILURE;
5565 // TODO: bash prints a string representation
5566 // of job being foregrounded (like "sleep 1 | cat")
5567 if (argv[0][0] == 'f') {
5568 /* Put the job into the foreground. */
5569 tcsetpgrp(G_interactive_fd, pi->pgrp);
5572 /* Restart the processes in the job */
5573 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
5574 for (i = 0; i < pi->num_cmds; i++) {
5575 debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
5576 pi->cmds[i].is_stopped = 0;
5578 pi->stopped_cmds = 0;
5580 i = kill(- pi->pgrp, SIGCONT);
5582 if (errno == ESRCH) {
5583 delete_finished_bg_job(pi);
5584 return EXIT_SUCCESS;
5586 bb_perror_msg("kill (SIGCONT)");
5589 if (argv[0][0] == 'f') {
5591 return checkjobs_and_fg_shell(pi);
5593 return EXIT_SUCCESS;
5597 #if ENABLE_HUSH_HELP
5598 static int builtin_help(char **argv UNUSED_PARAM)
5600 const struct built_in_command *x;
5603 "Built-in commands:\n"
5604 "------------------\n");
5605 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
5606 printf("%s\t%s\n", x->cmd, x->descr);
5609 return EXIT_SUCCESS;
5614 static int builtin_jobs(char **argv UNUSED_PARAM)
5617 const char *status_string;
5619 for (job = G.job_list; job; job = job->next) {
5620 if (job->alive_cmds == job->stopped_cmds)
5621 status_string = "Stopped";
5623 status_string = "Running";
5625 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
5627 return EXIT_SUCCESS;
5631 static int builtin_pwd(char **argv UNUSED_PARAM)
5634 return EXIT_SUCCESS;
5637 static int builtin_read(char **argv)
5640 const char *name = argv[1] ? argv[1] : "REPLY";
5641 //TODO: check that argv[1] is a valid variable name
5643 string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
5644 return set_local_var(string, 0, 0);
5647 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
5648 * built-in 'set' handler
5650 * set [-abCefhmnuvx] [-o option] [argument...]
5651 * set [+abCefhmnuvx] [+o option] [argument...]
5652 * set -- [argument...]
5655 * Implementations shall support the options in both their hyphen and
5656 * plus-sign forms. These options can also be specified as options to sh.
5658 * Write out all variables and their values: set
5659 * Set $1, $2, and $3 and set "$#" to 3: set c a b
5660 * Turn on the -x and -v options: set -xv
5661 * Unset all positional parameters: set --
5662 * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
5663 * Set the positional parameters to the expansion of x, even if x expands
5664 * with a leading '-' or '+': set -- $x
5666 * So far, we only support "set -- [argument...]" and some of the short names.
5668 static int builtin_set(char **argv)
5671 char **pp, **g_argv;
5672 char *arg = *++argv;
5676 for (e = G.top_var; e; e = e->next)
5678 return EXIT_SUCCESS;
5682 if (!strcmp(arg, "--")) {
5687 if (arg[0] == '+' || arg[0] == '-') {
5688 for (n = 1; arg[n]; ++n)
5689 if (set_mode(arg[0], arg[n]))
5695 } while ((arg = *++argv) != NULL);
5696 /* Now argv[0] is 1st argument */
5698 /* Only reset global_argv if we didn't process anything */
5700 return EXIT_SUCCESS;
5703 /* NB: G.global_argv[0] ($0) is never freed/changed */
5704 g_argv = G.global_argv;
5705 if (G.global_args_malloced) {
5711 G.global_args_malloced = 1;
5712 pp = xzalloc(sizeof(pp[0]) * 2);
5713 pp[0] = g_argv[0]; /* retain $0 */
5716 /* This realloc's G.global_argv */
5717 G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
5724 return EXIT_SUCCESS;
5726 /* Nothing known, so abort */
5728 bb_error_msg("set: %s: invalid option", arg);
5729 return EXIT_FAILURE;
5732 static int builtin_shift(char **argv)
5738 if (n >= 0 && n < G.global_argc) {
5739 if (G.global_args_malloced) {
5742 free(G.global_argv[m++]);
5745 memmove(&G.global_argv[1], &G.global_argv[n+1],
5746 G.global_argc * sizeof(G.global_argv[0]));
5747 return EXIT_SUCCESS;
5749 return EXIT_FAILURE;
5752 static int builtin_source(char **argv)
5756 if (*++argv == NULL)
5757 return EXIT_FAILURE;
5759 /* XXX search through $PATH is missing */
5760 input = fopen_or_warn(*argv, "r");
5762 /* bb_perror_msg("%s", *argv); - done by fopen_or_warn */
5763 return EXIT_FAILURE;
5765 close_on_exec_on(fileno(input));
5767 /* Now run the file */
5769 /* XXX argv and argc are broken; need to save old G.global_argv
5770 * (pointer only is OK!) on this stack frame,
5771 * set G.global_argv=argv+1, recurse, and restore. */
5772 parse_and_run_file(input);
5774 return G.last_return_code;
5777 static int builtin_umask(char **argv)
5780 const char *arg = argv[1];
5782 //TODO: umask may take chmod-like symbolic masks
5783 new_umask = bb_strtou(arg, NULL, 8);
5785 //Message? bash examples:
5786 //bash: umask: 'q': invalid symbolic mode operator
5787 //bash: umask: 999: octal number out of range
5788 return EXIT_FAILURE;
5791 new_umask = umask(0);
5792 printf("%.3o\n", (unsigned) new_umask);
5793 /* fall through and restore new_umask which we set to 0 */
5796 return EXIT_SUCCESS;
5799 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
5800 static int builtin_unset(char **argv)
5806 return EXIT_SUCCESS;
5809 if (argv[0][0] == '-') {
5810 switch (argv[0][1]) {
5816 bb_error_msg("unset: %s: invalid option", *argv);
5817 return EXIT_FAILURE;
5819 //TODO: disallow "unset -vf ..." too
5826 if (unset_local_var(*argv)) {
5827 /* unset <nonexistent_var> doesn't fail.
5828 * Error is when one tries to unset RO var.
5829 * Message was printed by unset_local_var. */
5833 #if ENABLE_HUSH_FUNCTIONS
5835 unset_local_func(*argv);
5843 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
5844 static int builtin_wait(char **argv)
5846 int ret = EXIT_SUCCESS;
5849 if (*++argv == NULL) {
5850 /* Don't care about wait results */
5851 /* Note 1: must wait until there are no more children */
5852 /* Note 2: must be interruptible */
5854 * $ sleep 3 & sleep 6 & wait
5859 * $ sleep 3 & sleep 6 & wait
5863 * ^C <-- after ~4 sec from keyboard
5866 sigaddset(&G.blocked_set, SIGCHLD);
5867 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5870 if (errno == ECHILD)
5872 /* Wait for SIGCHLD or any other signal of interest */
5873 /* sigtimedwait with infinite timeout: */
5874 sig = sigwaitinfo(&G.blocked_set, NULL);
5876 sig = check_and_run_traps(sig);
5877 if (sig && sig != SIGCHLD) { /* see note 2 */
5883 sigdelset(&G.blocked_set, SIGCHLD);
5884 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5888 /* This is probably buggy wrt interruptible-ness */
5890 pid_t pid = bb_strtou(*argv, NULL, 10);
5892 /* mimic bash message */
5893 bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
5894 return EXIT_FAILURE;
5896 if (waitpid(pid, &status, 0) == pid) {
5897 if (WIFSIGNALED(status))
5898 ret = 128 + WTERMSIG(status);
5899 else if (WIFEXITED(status))
5900 ret = WEXITSTATUS(status);
5904 bb_perror_msg("wait %s", *argv);
5913 #if ENABLE_HUSH_LOOPS
5914 static int builtin_break(char **argv)
5916 if (G.depth_of_loop == 0) {
5917 bb_error_msg("%s: only meaningful in a loop", argv[0]);
5918 return EXIT_SUCCESS; /* bash compat */
5920 G.flag_break_continue++; /* BC_BREAK = 1 */
5921 G.depth_break_continue = 1;
5923 G.depth_break_continue = bb_strtou(argv[1], NULL, 10);
5924 if (errno || !G.depth_break_continue || argv[2]) {
5925 bb_error_msg("%s: bad arguments", argv[0]);
5926 G.flag_break_continue = BC_BREAK;
5927 G.depth_break_continue = UINT_MAX;
5930 if (G.depth_of_loop < G.depth_break_continue)
5931 G.depth_break_continue = G.depth_of_loop;
5932 return EXIT_SUCCESS;
5935 static int builtin_continue(char **argv)
5937 G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
5938 return builtin_break(argv);