1 /* vi: set sw=4 ts=4: */
3 * A prototype Bourne shell grammar parser.
4 * Intended to follow the original Thompson and Ritchie
5 * "small and simple is beautiful" philosophy, which
6 * incidentally is a good match to today's BusyBox.
8 * Copyright (C) 2000,2001 Larry Doolittle <larry@doolittle.boa.org>
11 * The parser routines proper are all original material, first
12 * written Dec 2000 and Jan 2001 by Larry Doolittle. The
13 * execution engine, the builtins, and much of the underlying
14 * support has been adapted from busybox-0.49pre's lash, which is
15 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
16 * written by Erik Andersen <andersen@codepoet.org>. That, in turn,
17 * is based in part on ladsh.c, by Michael K. Johnson and Erik W.
18 * Troan, which they placed in the public domain. I don't know
19 * how much of the Johnson/Troan code has survived the repeated
23 * o_addchr() derived from similar w_addchar function in glibc-2.2.
24 * setup_redirect(), redirect_opt_num(), and big chunks of main()
25 * and many builtins derived from contributions by Erik Andersen.
26 * Miscellaneous bugfixes from Matt Kraai.
28 * There are two big (and related) architecture differences between
29 * this parser and the lash parser. One is that this version is
30 * actually designed from the ground up to understand nearly all
31 * of the Bourne grammar. The second, consequential change is that
32 * the parser and input reader have been turned inside out. Now,
33 * the parser is in control, and asks for input as needed. The old
34 * way had the input reader in control, and it asked for parsing to
35 * take place as needed. The new way makes it much easier to properly
36 * handle the recursion implicit in the various substitutions, especially
37 * across continuation lines.
39 * POSIX syntax not implemented:
41 * <(list) and >(list) Process Substitution
42 * Here Documents ( << word )
45 * Parameter Expansion for substring processing ${var#word} ${var%word}
47 * Bash stuff maybe optional enable:
48 * &> and >& redirection of stdout+stderr
50 * reserved words: [[ ]] function select
51 * substrings ${var:1:5}
54 * job handling woefully incomplete and buggy (improved --vda)
56 * port selected bugfixes from post-0.49 busybox lash - done?
57 * change { and } from special chars to reserved words
58 * builtins: return, trap, ulimit
59 * test magic exec with redirection only
60 * follow IFS rules more precisely, including update semantics
61 * figure out what to do with backslash-newline
62 * propagate syntax errors, die on resource errors?
63 * continuation lines, both explicit and implicit - done?
65 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
68 #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */
69 //TODO: pull in some .h and find out whether we have SINGLE_APPLET_MAIN?
70 //#include "applet_tables.h" doesn't work
72 /* #include <dmalloc.h> */
78 #ifdef WANT_TO_TEST_NOMMU
83 # define USE_FOR_NOMMU(...) __VA_ARGS__
84 # define USE_FOR_MMU(...)
87 #define HUSH_VER_STR "0.93"
89 #if defined SINGLE_APPLET_MAIN
90 /* STANDALONE does not make sense, and won't compile */
91 #undef CONFIG_FEATURE_SH_STANDALONE
92 #undef ENABLE_FEATURE_SH_STANDALONE
93 #undef USE_FEATURE_SH_STANDALONE
94 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
95 #define ENABLE_FEATURE_SH_STANDALONE 0
96 #define USE_FEATURE_SH_STANDALONE(...)
97 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
100 #if !ENABLE_HUSH_INTERACTIVE
101 #undef ENABLE_FEATURE_EDITING
102 #define ENABLE_FEATURE_EDITING 0
103 #undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
104 #define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
107 /* Do we support ANY keywords? */
108 #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
109 #define HAS_KEYWORDS 1
110 #define IF_HAS_KEYWORDS(...) __VA_ARGS__
111 #define IF_HAS_NO_KEYWORDS(...)
113 #define HAS_KEYWORDS 0
114 #define IF_HAS_KEYWORDS(...)
115 #define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__
118 /* Keep unconditionally on for now */
121 #define ENABLE_HUSH_FUNCTIONS 0
124 /* If you comment out one of these below, it will be #defined later
125 * to perform debug printfs to stderr: */
126 #define debug_printf(...) do {} while (0)
127 /* Finer-grained debug switches */
128 #define debug_printf_parse(...) do {} while (0)
129 #define debug_print_tree(a, b) do {} while (0)
130 #define debug_printf_exec(...) do {} while (0)
131 #define debug_printf_env(...) do {} while (0)
132 #define debug_printf_jobs(...) do {} while (0)
133 #define debug_printf_expand(...) do {} while (0)
134 #define debug_printf_glob(...) do {} while (0)
135 #define debug_printf_list(...) do {} while (0)
136 #define debug_printf_subst(...) do {} while (0)
137 #define debug_printf_clean(...) do {} while (0)
140 #define debug_printf(...) fprintf(stderr, __VA_ARGS__)
143 #ifndef debug_printf_parse
144 #define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__)
147 #ifndef debug_printf_exec
148 #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__)
151 #ifndef debug_printf_env
152 #define debug_printf_env(...) fprintf(stderr, __VA_ARGS__)
155 #ifndef debug_printf_jobs
156 #define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__)
162 #ifndef debug_printf_expand
163 #define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__)
164 #define DEBUG_EXPAND 1
166 #define DEBUG_EXPAND 0
169 #ifndef debug_printf_glob
170 #define debug_printf_glob(...) fprintf(stderr, __VA_ARGS__)
176 #ifndef debug_printf_list
177 #define debug_printf_list(...) fprintf(stderr, __VA_ARGS__)
180 #ifndef debug_printf_subst
181 #define debug_printf_subst(...) fprintf(stderr, __VA_ARGS__)
184 #ifndef debug_printf_clean
185 /* broken, of course, but OK for testing */
186 static const char *indenter(int i)
188 static const char blanks[] ALIGN1 =
190 return &blanks[sizeof(blanks) - i - 1];
192 #define debug_printf_clean(...) fprintf(stderr, __VA_ARGS__)
193 #define DEBUG_CLEAN 1
197 static void debug_print_strings(const char *prefix, char **vv)
199 fprintf(stderr, "%s:\n", prefix);
201 fprintf(stderr, " '%s'\n", *vv++);
204 #define debug_print_strings(prefix, vv) ((void)0)
208 * Leak hunting. Use hush_leaktool.sh for post-processing.
210 #ifdef FOR_HUSH_LEAKTOOL
211 static void *xxmalloc(int lineno, size_t size)
213 void *ptr = xmalloc((size + 0xff) & ~0xff);
214 fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
217 static void *xxrealloc(int lineno, void *ptr, size_t size)
219 ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
220 fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
223 static char *xxstrdup(int lineno, const char *str)
225 char *ptr = xstrdup(str);
226 fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
229 static void xxfree(void *ptr)
231 fdprintf(2, "free %p\n", ptr);
234 #define xmalloc(s) xxmalloc(__LINE__, s)
235 #define xrealloc(p, s) xxrealloc(__LINE__, p, s)
236 #define xstrdup(s) xxstrdup(__LINE__, s)
237 #define free(p) xxfree(p)
241 #define ERR_PTR ((void*)(long)1)
243 static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="HUSH_VER_STR;
245 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
247 #define SPECIAL_VAR_SYMBOL 3
249 typedef enum redir_type {
251 REDIRECT_OVERWRITE = 2,
257 /* The descrip member of this structure is only used to make
258 * debugging output pretty */
259 static const struct {
261 signed char default_fd;
265 { O_RDONLY, 0, "<" },
266 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
267 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
268 { O_RDONLY, -1, "<<" },
272 typedef enum pipe_style {
279 typedef enum reserved_style {
288 #if ENABLE_HUSH_LOOPS
295 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
300 /* two pseudo-keywords support contrived "case" syntax: */
301 RES_MATCH , /* "word)" */
302 RES_CASEI , /* "this command is inside CASE" */
309 typedef struct o_string {
311 int length; /* position where data is appended */
313 /* Protect newly added chars against globbing
314 * (by prepending \ to *, ?, [, \) */
318 smallint has_empty_slot;
319 smallint o_assignment; /* 0:maybe, 1:yes, 2:no */
322 MAYBE_ASSIGNMENT = 0,
323 DEFINITELY_ASSIGNMENT = 1,
325 WORD_IS_KEYWORD = 3, /* not assigment, but next word may be: "if v=xyz cmd;" */
327 /* Used for initialization: o_string foo = NULL_O_STRING; */
328 #define NULL_O_STRING { NULL }
330 /* I can almost use ordinary FILE*. Is open_memstream() universally
331 * available? Where is it documented? */
332 typedef struct in_str {
334 /* eof_flag=1: last char in ->p is really an EOF */
335 char eof_flag; /* meaningless if ->p == NULL */
337 #if ENABLE_HUSH_INTERACTIVE
339 smallint promptmode; /* 0: PS1, 1: PS2 */
342 int (*get) (struct in_str *);
343 int (*peek) (struct in_str *);
345 #define i_getch(input) ((input)->get(input))
346 #define i_peek(input) ((input)->peek(input))
348 struct redir_struct {
349 struct redir_struct *next;
350 char *rd_filename; /* filename */
351 int fd; /* file descriptor being redirected */
352 int dup; /* -1, or file descriptor being duplicated */
353 smallint /*enum redir_type*/ rd_type;
357 pid_t pid; /* 0 if exited */
358 int assignment_cnt; /* how many argv[i] are assignments? */
359 smallint is_stopped; /* is the command currently running? */
360 smallint grp_type; /* GRP_xxx */
361 struct pipe *group; /* if non-NULL, this "command" is { list },
362 * ( list ), or a compound statement */
364 char *group_as_string;
366 char **argv; /* command name and arguments */
367 struct redir_struct *redirects; /* I/O redirections */
369 /* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
370 * and on execution these are substituted with their values.
371 * Substitution can make _several_ words out of one argv[n]!
372 * Example: argv[0]=='.^C*^C.' here: echo .$*.
373 * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
376 #define GRP_SUBSHELL 1
377 #if ENABLE_HUSH_FUNCTIONS
378 #define GRP_FUNCTION 2
383 int num_cmds; /* total number of commands in job */
384 int alive_cmds; /* number of commands running (not exited) */
385 int stopped_cmds; /* number of commands alive, but stopped */
387 int jobid; /* job number */
388 pid_t pgrp; /* process group ID for the job */
389 char *cmdtext; /* name of job */
391 struct command *cmds; /* array of commands in pipe */
392 smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
393 IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */
394 IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */
397 /* This holds pointers to the various results of parsing */
398 struct parse_context {
399 /* linked list of pipes */
400 struct pipe *list_head;
401 /* last pipe (being constructed right now) */
403 /* last command in pipe (being constructed right now) */
404 struct command *command;
405 /* last redirect in command->redirects list */
406 struct redir_struct *pending_redirect;
412 smallint ctx_inverted; /* "! cmd | cmd" */
414 smallint ctx_dsemicolon; /* ";;" seen */
416 /* bitmask of FLAG_xxx, for figuring out valid reserved words */
418 /* group we are enclosed in:
419 * example: "if pipe1; pipe2; then pipe3; fi"
420 * when we see "if" or "then", we malloc and copy current context,
421 * and make ->stack point to it. then we parse pipeN.
422 * when closing "then" / fi" / whatever is found,
423 * we move list_head into ->stack->command->group,
424 * copy ->stack into current context, and delete ->stack.
425 * (parsing of { list } and ( list ) doesn't use this method)
427 struct parse_context *stack;
431 /* On program start, environ points to initial environment.
432 * putenv adds new pointers into it, unsetenv removes them.
433 * Neither of these (de)allocates the strings.
434 * setenv allocates new strings in malloc space and does putenv,
435 * and thus setenv is unusable (leaky) for shell's purposes */
436 #define setenv(...) setenv_is_leaky_dont_use()
438 struct variable *next;
439 char *varstr; /* points to "name=" portion */
440 int max_len; /* if > 0, name is part of initial env; else name is malloced */
441 smallint flg_export; /* putenv should be done on this var */
442 smallint flg_read_only;
451 /* "Globals" within this file */
452 /* Sorted roughly by size (smaller offsets == smaller code) */
454 #if ENABLE_HUSH_INTERACTIVE
455 /* 'interactive_fd' is a fd# open to ctty, if we have one
456 * _AND_ if we decided to act interactively */
460 #define G_interactive_fd (G.interactive_fd)
462 #define G_interactive_fd 0
464 #if ENABLE_FEATURE_EDITING
465 line_input_t *line_input_state;
471 pid_t saved_tty_pgrp;
473 struct pipe *job_list;
474 struct pipe *toplevel_list;
475 //// smallint ctrl_z_flag;
477 smallint flag_SIGINT;
478 #if ENABLE_HUSH_LOOPS
479 smallint flag_break_continue;
482 /* These four support $?, $#, and $1 */
483 smalluint last_return_code;
484 /* is global_argv and global_argv[1..n] malloced? (note: not [0]) */
485 smalluint global_args_malloced;
486 /* how many non-NULL argv's we have. NB: $# + 1 */
489 #if ENABLE_HUSH_LOOPS
490 unsigned depth_break_continue;
491 unsigned depth_of_loop;
495 struct variable *top_var; /* = &G.shell_ver (set in main()) */
496 struct variable shell_ver;
497 /* Signal and trap handling */
498 // unsigned count_SIGCHLD;
499 // unsigned handled_SIGCHLD;
500 /* which signals have non-DFL handler (even with no traps set)? */
501 unsigned non_DFL_mask;
502 char **traps; /* char *traps[NSIG] */
503 sigset_t blocked_set;
504 sigset_t inherited_set;
505 char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
506 #if ENABLE_FEATURE_SH_STANDALONE
507 struct nofork_save_area nofork_save;
510 sigjmp_buf toplevel_jb;
513 #define G (*ptr_to_globals)
514 /* Not #defining name to G.name - this quickly gets unwieldy
515 * (too many defines). Also, I actually prefer to see when a variable
516 * is global, thus "G." prefix is a useful hint */
517 #define INIT_G() do { \
518 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
522 /* Function prototypes for builtins */
523 static int builtin_cd(char **argv);
524 static int builtin_echo(char **argv);
525 static int builtin_eval(char **argv);
526 static int builtin_exec(char **argv);
527 static int builtin_exit(char **argv);
528 static int builtin_export(char **argv);
530 static int builtin_fg_bg(char **argv);
531 static int builtin_jobs(char **argv);
534 static int builtin_help(char **argv);
536 static int builtin_pwd(char **argv);
537 static int builtin_read(char **argv);
538 static int builtin_test(char **argv);
539 static int builtin_trap(char **argv);
540 static int builtin_true(char **argv);
541 static int builtin_set(char **argv);
542 static int builtin_shift(char **argv);
543 static int builtin_source(char **argv);
544 static int builtin_umask(char **argv);
545 static int builtin_unset(char **argv);
546 static int builtin_wait(char **argv);
547 #if ENABLE_HUSH_LOOPS
548 static int builtin_break(char **argv);
549 static int builtin_continue(char **argv);
552 /* Table of built-in functions. They can be forked or not, depending on
553 * context: within pipes, they fork. As simple commands, they do not.
554 * When used in non-forking context, they can change global variables
555 * in the parent shell process. If forked, of course they cannot.
556 * For example, 'unset foo | whatever' will parse and run, but foo will
557 * still be set at the end. */
558 struct built_in_command {
560 int (*function)(char **argv);
563 #define BLTIN(cmd, func, help) { cmd, func, help }
565 #define BLTIN(cmd, func, help) { cmd, func }
569 /* For now, echo and test are unconditionally enabled.
570 * Maybe make it configurable? */
571 static const struct built_in_command bltins[] = {
572 BLTIN("." , builtin_source , "Run commands in a file"),
573 BLTIN(":" , builtin_true , "No-op"),
574 BLTIN("[" , builtin_test , "Test condition"),
576 BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
578 #if ENABLE_HUSH_LOOPS
579 BLTIN("break" , builtin_break , "Exit from a loop"),
581 BLTIN("cd" , builtin_cd , "Change directory"),
582 #if ENABLE_HUSH_LOOPS
583 BLTIN("continue", builtin_continue, "Start new loop iteration"),
585 BLTIN("echo" , builtin_echo , "Write to stdout"),
586 BLTIN("eval" , builtin_eval , "Construct and run shell command"),
587 BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
588 BLTIN("exit" , builtin_exit , "Exit"),
589 BLTIN("export" , builtin_export , "Set environment variable"),
591 BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
594 BLTIN("help" , builtin_help , "List shell built-in commands"),
597 BLTIN("jobs" , builtin_jobs , "List active jobs"),
599 BLTIN("pwd" , builtin_pwd , "Print current directory"),
600 BLTIN("read" , builtin_read , "Input environment variable"),
601 // BLTIN("return" , builtin_return , "Return from a function"),
602 BLTIN("set" , builtin_set , "Set/unset shell local variables"),
603 BLTIN("shift" , builtin_shift , "Shift positional parameters"),
604 BLTIN("test" , builtin_test , "Test condition"),
605 BLTIN("trap" , builtin_trap , "Trap signals"),
606 // BLTIN("ulimit" , builtin_return , "Control resource limits"),
607 BLTIN("umask" , builtin_umask , "Set file creation mask"),
608 BLTIN("unset" , builtin_unset , "Unset environment variable"),
609 BLTIN("wait" , builtin_wait , "Wait for process"),
613 static void maybe_die(const char *notice, const char *msg)
615 /* Was using fancy stuff:
616 * (G_interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...)
617 * but it SEGVs. ?! Oh well... explicit temp ptr works around that */
618 void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die;
619 #if ENABLE_HUSH_INTERACTIVE
620 if (G_interactive_fd)
623 fp(msg ? "%s: %s" : notice, notice, msg);
626 #define syntax(msg) maybe_die("syntax error", msg);
628 /* Debug -- trick gcc to expand __LINE__ and convert to string */
629 #define __syntax(msg, line) maybe_die("syntax error hush.c:" # line, msg)
630 #define _syntax(msg, line) __syntax(msg, line)
631 #define syntax(msg) _syntax(msg, __LINE__)
635 static int glob_needed(const char *s)
640 if (*s == '*' || *s == '[' || *s == '?')
647 static int is_assignment(const char *s)
649 if (!s || !(isalpha(*s) || *s == '_'))
652 while (isalnum(*s) || *s == '_')
657 /* Replace each \x with x in place, return ptr past NUL. */
658 static char *unbackslash(char *src)
664 if ((*dst++ = *src++) == '\0')
670 static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
691 v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
692 v[count1 + count2] = NULL;
695 v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
699 static char **add_string_to_strings(char **strings, char *add)
704 return add_strings_to_strings(strings, v, /*dup:*/ 0);
707 static void putenv_all(char **strings)
712 debug_printf_env("putenv '%s'\n", *strings);
717 static char **putenv_all_and_save_old(char **strings)
727 eq = strchr(*strings, '=');
730 v = getenv(*strings);
733 /* v points to VAL in VAR=VAL, go back to VAR */
734 v -= (eq - *strings) + 1;
735 old = add_string_to_strings(old, v);
744 static void free_strings_and_unsetenv(char **strings, int unset)
754 debug_printf_env("unsetenv '%s'\n", *v);
762 static void free_strings(char **strings)
764 free_strings_and_unsetenv(strings, 0);
768 /* Basic theory of signal handling in shell
769 * ========================================
770 * This does not describe what hush does, rather, it is current understanding
771 * what it _should_ do. If it doesn't, it's a bug.
772 * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
774 * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
775 * is finished or backgrounded. It is the same in interactive and
776 * non-interactive shells, and is the same regardless of whether
777 * a user trap handler is installed or a shell special one is in effect.
778 * ^C or ^Z from keyboard seem to execute "at once" because it usually
779 * backgrounds (i.e. stops) or kills all members of currently running
782 * Wait builtin in interruptible by signals for which user trap is set
783 * or by SIGINT in interactive shell.
785 * Trap handlers will execute even within trap handlers. (right?)
787 * User trap handlers are forgotten when subshell ("(cmd)") is entered. [TODO]
789 * If job control is off, backgrounded commands ("cmd &")
790 * have SIGINT, SIGQUIT set to SIG_IGN.
792 * Commands run in command substitution ("`cmd`")
793 * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
795 * Ordinary commands have signals set to SIG_IGN/DFL set as inherited
796 * by the shell from its parent.
798 * Siganls which differ from SIG_DFL action
799 * (note: child (i.e., [v]forked) shell is not an interactive shell):
802 * SIGTERM (interactive): ignore
803 * SIGHUP (interactive):
804 * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
805 * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
806 * (note that ^Z is handled not by trapping SIGTSTP, but by seeing
807 * that all pipe members are stopped) (right?)
808 * SIGINT (interactive): wait for last pipe, ignore the rest
809 * of the command line, show prompt. NB: ^C does not send SIGINT
810 * to interactive shell while shell is waiting for a pipe,
811 * since shell is bg'ed (is not in foreground process group).
812 * (check/expand this)
813 * Example 1: this waits 5 sec, but does not execute ls:
814 * "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
815 * Example 2: this does not wait and does not execute ls:
816 * "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
817 * Example 3: this does not wait 5 sec, but executes ls:
818 * "sleep 5; ls -l" + press ^C
820 * (What happens to signals which are IGN on shell start?)
821 * (What happens with signal mask on shell start?)
823 * Implementation in hush
824 * ======================
825 * We use in-kernel pending signal mask to determine which signals were sent.
826 * We block all signals which we don't want to take action immediately,
827 * i.e. we block all signals which need to have special handling as described
828 * above, and all signals which have traps set.
829 * After each pipe execution, we extract any pending signals via sigtimedwait()
832 * unsigned non_DFL_mask: a mask of such "special" signals
833 * sigset_t blocked_set: current blocked signal set
836 * clear bit in blocked_set unless it is also in non_DFL_mask
837 * "trap 'cmd' SIGxxx":
838 * set bit in blocked_set (even if 'cmd' is '')
839 * after [v]fork, if we plan to be a shell:
840 * nothing for {} child shell (say, "true | { true; true; } | true")
841 * unset all traps if () shell. [TODO]
842 * after [v]fork, if we plan to exec:
843 * POSIX says pending signal mask is cleared in child - no need to clear it.
844 * Restore blocked signal set to one inherited by shell just prior to exec.
846 * Note: as a result, we do not use signal handlers much. The only uses
847 * are to count SIGCHLDs [disabled - bug somewhere, + bloat]
848 * and to restore tty pgrp on signal-induced exit.
850 * TODO: check/fix wait builtin to be interruptible.
853 //static void SIGCHLD_handler(int sig UNUSED_PARAM)
855 // G.count_SIGCHLD++;
858 /* called once at shell init */
859 static void init_signal_mask(void)
862 unsigned mask = (1 << SIGQUIT);
863 if (G_interactive_fd) {
869 | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
874 G.non_DFL_mask = mask;
876 sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
880 sigaddset(&G.blocked_set, sig);
884 sigdelset(&G.blocked_set, SIGCHLD);
885 sigprocmask(SIG_SETMASK, &G.blocked_set, &G.inherited_set);
888 static int check_and_run_traps(int sig)
890 static const struct timespec zero_timespec = { 0, 0 };
891 smalluint save_rcode;
897 sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec);
902 if (G.traps && G.traps[sig]) {
903 if (G.traps[sig][0]) {
904 /* We have user-defined handler */
905 char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL };
906 save_rcode = G.last_return_code;
909 G.last_return_code = save_rcode;
910 } /* else: "" trap, ignoring signal */
913 /* not a trap: special action */
916 // G.count_SIGCHLD++;
925 default: /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
934 /* Restores tty foreground process group, and exits.
935 * May be called as signal handler for fatal signal
936 * (will faithfully resend signal to itself, producing correct exit state)
937 * or called directly with -EXITCODE.
938 * We also call it if xfunc is exiting. */
939 static void sigexit(int sig) NORETURN;
940 static void sigexit(int sig)
942 /* Disable all signals: job control, SIGPIPE, etc. */
943 sigprocmask_allsigs(SIG_BLOCK);
945 /* Careful: we can end up here after [v]fork. Do not restore
946 * tty pgrp then, only top-level shell process does that */
947 if (G_interactive_fd && getpid() == G.root_pid)
948 tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
950 /* Not a signal, just exit */
954 kill_myself_with_sig(sig); /* does not return */
958 static void maybe_set_sighandler(int sig)
960 void (*handler)(int);
961 /* non_DFL_mask'ed signals are, well, masked,
962 * no need to set handler for them.
964 if (!((G.non_DFL_mask >> sig) & 1)) {
965 handler = signal(sig, sigexit);
966 if (handler == SIG_IGN) /* oops... restore back to IGN! */
967 signal(sig, handler);
970 /* Used only to set handler to restore pgrp on exit */
971 static void set_fatal_signals_to_sigexit(void)
974 maybe_set_sighandler(SIGILL );
975 maybe_set_sighandler(SIGFPE );
976 maybe_set_sighandler(SIGBUS );
977 maybe_set_sighandler(SIGSEGV);
978 maybe_set_sighandler(SIGTRAP);
979 } /* else: hush is perfect. what SEGV? */
981 maybe_set_sighandler(SIGABRT);
983 /* bash 3.2 seems to handle these just like 'fatal' ones */
984 maybe_set_sighandler(SIGPIPE);
985 maybe_set_sighandler(SIGALRM);
986 maybe_set_sighandler(SIGHUP );
988 /* if we aren't interactive... but in this case
989 * we never want to restore pgrp on exit, and this fn is not called */
990 /*maybe_set_sighandler(SIGTERM);*/
991 /*maybe_set_sighandler(SIGINT );*/
996 #define set_fatal_signals_to_sigexit(handler) ((void)0)
1000 /* Restores tty foreground process group, and exits. */
1001 static void hush_exit(int exitcode) NORETURN;
1002 static void hush_exit(int exitcode)
1004 if (G.traps && G.traps[0] && G.traps[0][0]) {
1005 char *argv[] = { NULL, xstrdup(G.traps[0]), NULL };
1011 fflush(NULL); /* flush all streams */
1012 sigexit(- (exitcode & 0xff));
1019 static const char *set_cwd(void)
1021 /* xrealloc_getcwd_or_warn(arg) calls free(arg),
1022 * we must not try to free(bb_msg_unknown) */
1023 if (G.cwd == bb_msg_unknown)
1025 G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
1027 G.cwd = bb_msg_unknown;
1032 /* Get/check local shell variables */
1033 static struct variable *get_local_var(const char *name)
1035 struct variable *cur;
1041 for (cur = G.top_var; cur; cur = cur->next) {
1042 if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
1048 static const char *get_local_var_value(const char *src)
1050 struct variable *var = get_local_var(src);
1052 return strchr(var->varstr, '=') + 1;
1056 /* str holds "NAME=VAL" and is expected to be malloced.
1057 * We take ownership of it.
1061 * -1: if NAME is set, leave export status alone
1062 * if NAME is not set, do not export
1063 * flg_read_only is set only when we handle -R var=val
1066 #define set_local_var(str, flg_export, flg_read_only) \
1067 set_local_var(str, flg_export)
1069 static int set_local_var(char *str, int flg_export, int flg_read_only)
1071 struct variable *cur;
1075 value = strchr(str, '=');
1076 if (!value) { /* not expected to ever happen? */
1081 name_len = value - str + 1; /* including '=' */
1082 cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
1084 if (strncmp(cur->varstr, str, name_len) != 0) {
1086 /* Bail out. Note that now cur points
1087 * to last var in linked list */
1093 /* We found an existing var with this name */
1095 if (cur->flg_read_only) {
1099 bb_error_msg("%s: readonly variable", str);
1103 debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
1104 unsetenv(str); /* just in case */
1106 if (strcmp(cur->varstr, str) == 0) {
1111 if (cur->max_len >= strlen(str)) {
1112 /* This one is from startup env, reuse space */
1113 strcpy(cur->varstr, str);
1116 /* max_len == 0 signifies "malloced" var, which we can
1117 * (and has to) free */
1121 goto set_str_and_exp;
1124 /* Not found - create next variable struct */
1125 cur->next = xzalloc(sizeof(*cur));
1130 cur->flg_read_only = flg_read_only;
1132 if (flg_export == 1)
1133 cur->flg_export = 1;
1134 if (cur->flg_export) {
1135 debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
1136 return putenv(cur->varstr);
1141 static int unset_local_var(const char *name)
1143 struct variable *cur;
1144 struct variable *prev = prev; /* for gcc */
1148 return EXIT_SUCCESS;
1149 name_len = strlen(name);
1152 if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
1153 if (cur->flg_read_only) {
1154 bb_error_msg("%s: readonly variable", name);
1155 return EXIT_FAILURE;
1157 /* prev is ok to use here because 1st variable, HUSH_VERSION,
1158 * is ro, and we cannot reach this code on the 1st pass */
1159 prev->next = cur->next;
1160 debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
1161 bb_unsetenv(cur->varstr);
1165 return EXIT_SUCCESS;
1170 return EXIT_SUCCESS;
1173 #if ENABLE_SH_MATH_SUPPORT
1174 #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c)))
1175 #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c)))
1176 static char *endofname(const char *name)
1184 if (!is_in_name(*p))
1190 static void arith_set_local_var(const char *name, const char *val, int flags)
1192 /* arith code doesnt malloc space, so do it for it */
1193 char *var = xasprintf("%s=%s", name, val);
1194 set_local_var(var, flags, 0);
1202 static int static_get(struct in_str *i)
1211 static int static_peek(struct in_str *i)
1216 #if ENABLE_HUSH_INTERACTIVE
1218 static void cmdedit_set_initial_prompt(void)
1220 if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1221 G.PS1 = getenv("PS1");
1228 static const char* setup_prompt_string(int promptmode)
1230 const char *prompt_str;
1231 debug_printf("setup_prompt_string %d ", promptmode);
1232 if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1233 /* Set up the prompt */
1234 if (promptmode == 0) { /* PS1 */
1236 G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#');
1241 prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
1242 debug_printf("result '%s'\n", prompt_str);
1246 static void get_user_input(struct in_str *i)
1249 const char *prompt_str;
1251 prompt_str = setup_prompt_string(i->promptmode);
1252 #if ENABLE_FEATURE_EDITING
1253 /* Enable command line editing only while a command line
1254 * is actually being read */
1257 /* buglet: SIGINT will not make new prompt to appear _at once_,
1258 * only after <Enter>. (^C will work) */
1259 r = read_line_input(prompt_str, G.user_input_buf, BUFSIZ-1, G.line_input_state);
1260 /* catch *SIGINT* etc (^C is handled by read_line_input) */
1261 check_and_run_traps(0);
1262 } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */
1263 i->eof_flag = (r < 0);
1264 if (i->eof_flag) { /* EOF/error detected */
1265 G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
1266 G.user_input_buf[1] = '\0';
1271 fputs(prompt_str, stdout);
1273 G.user_input_buf[0] = r = fgetc(i->file);
1274 /*G.user_input_buf[1] = '\0'; - already is and never changed */
1275 //do we need check_and_run_traps(0)? (maybe only if stdin)
1276 } while (G.flag_SIGINT);
1277 i->eof_flag = (r == EOF);
1279 i->p = G.user_input_buf;
1282 #endif /* INTERACTIVE */
1284 /* This is the magic location that prints prompts
1285 * and gets data back from the user */
1286 static int file_get(struct in_str *i)
1290 /* If there is data waiting, eat it up */
1291 if (i->p && *i->p) {
1292 #if ENABLE_HUSH_INTERACTIVE
1296 if (i->eof_flag && !*i->p)
1299 /* need to double check i->file because we might be doing something
1300 * more complicated by now, like sourcing or substituting. */
1301 #if ENABLE_HUSH_INTERACTIVE
1302 if (G_interactive_fd && i->promptme && i->file == stdin) {
1305 } while (!*i->p); /* need non-empty line */
1306 i->promptmode = 1; /* PS2 */
1311 ch = fgetc(i->file);
1313 debug_printf("file_get: got a '%c' %d\n", ch, ch);
1314 #if ENABLE_HUSH_INTERACTIVE
1321 /* All the callers guarantee this routine will never be
1322 * used right after a newline, so prompting is not needed.
1324 static int file_peek(struct in_str *i)
1327 if (i->p && *i->p) {
1328 if (i->eof_flag && !i->p[1])
1332 ch = fgetc(i->file);
1333 i->eof_flag = (ch == EOF);
1334 i->peek_buf[0] = ch;
1335 i->peek_buf[1] = '\0';
1337 debug_printf("file_peek: got a '%c' %d\n", *i->p, *i->p);
1341 static void setup_file_in_str(struct in_str *i, FILE *f)
1343 i->peek = file_peek;
1345 #if ENABLE_HUSH_INTERACTIVE
1347 i->promptmode = 0; /* PS1 */
1353 static void setup_string_in_str(struct in_str *i, const char *s)
1355 i->peek = static_peek;
1356 i->get = static_get;
1357 #if ENABLE_HUSH_INTERACTIVE
1359 i->promptmode = 0; /* PS1 */
1369 #define B_CHUNK (32 * sizeof(char*))
1371 static void o_reset(o_string *o)
1379 static void o_free(o_string *o)
1382 memset(o, 0, sizeof(*o));
1385 static ALWAYS_INLINE void o_free_unsafe(o_string *o)
1390 static void o_grow_by(o_string *o, int len)
1392 if (o->length + len > o->maxlen) {
1393 o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
1394 o->data = xrealloc(o->data, 1 + o->maxlen);
1398 static void o_addchr(o_string *o, int ch)
1400 debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
1402 o->data[o->length] = ch;
1404 o->data[o->length] = '\0';
1407 static void o_addblock(o_string *o, const char *str, int len)
1410 memcpy(&o->data[o->length], str, len);
1412 o->data[o->length] = '\0';
1416 static void o_addstr(o_string *o, const char *str)
1418 o_addblock(o, str, strlen(str));
1422 static void o_addstr_with_NUL(o_string *o, const char *str)
1424 o_addblock(o, str, strlen(str) + 1);
1427 static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
1432 && (*str != '*' && *str != '?' && *str != '[')
1440 /* My analysis of quoting semantics tells me that state information
1441 * is associated with a destination, not a source.
1443 static void o_addqchr(o_string *o, int ch)
1446 char *found = strchr("*?[\\", ch);
1451 o->data[o->length] = '\\';
1454 o->data[o->length] = ch;
1456 o->data[o->length] = '\0';
1459 static void o_addQchr(o_string *o, int ch)
1462 if (o->o_escape && strchr("*?[\\", ch)) {
1464 o->data[o->length] = '\\';
1468 o->data[o->length] = ch;
1470 o->data[o->length] = '\0';
1473 static void o_addQstr(o_string *o, const char *str, int len)
1476 o_addblock(o, str, len);
1482 int ordinary_cnt = strcspn(str, "*?[\\");
1483 if (ordinary_cnt > len) /* paranoia */
1485 o_addblock(o, str, ordinary_cnt);
1486 if (ordinary_cnt == len)
1488 str += ordinary_cnt;
1489 len -= ordinary_cnt + 1; /* we are processing + 1 char below */
1493 if (ch) { /* it is necessarily one of "*?[\\" */
1495 o->data[o->length] = '\\';
1499 o->data[o->length] = ch;
1501 o->data[o->length] = '\0';
1505 /* A special kind of o_string for $VAR and `cmd` expansion.
1506 * It contains char* list[] at the beginning, which is grown in 16 element
1507 * increments. Actual string data starts at the next multiple of 16 * (char*).
1508 * list[i] contains an INDEX (int!) into this string data.
1509 * It means that if list[] needs to grow, data needs to be moved higher up
1510 * but list[i]'s need not be modified.
1511 * NB: remembering how many list[i]'s you have there is crucial.
1512 * o_finalize_list() operation post-processes this structure - calculates
1513 * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
1515 #if DEBUG_EXPAND || DEBUG_GLOB
1516 static void debug_print_list(const char *prefix, o_string *o, int n)
1518 char **list = (char**)o->data;
1519 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1521 fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n",
1522 prefix, list, n, string_start, o->length, o->maxlen);
1524 fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i],
1525 o->data + (int)list[i] + string_start,
1526 o->data + (int)list[i] + string_start);
1530 const char *p = o->data + (int)list[n - 1] + string_start;
1531 fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
1535 #define debug_print_list(prefix, o, n) ((void)0)
1538 /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
1539 * in list[n] so that it points past last stored byte so far.
1540 * It returns n+1. */
1541 static int o_save_ptr_helper(o_string *o, int n)
1543 char **list = (char**)o->data;
1547 if (!o->has_empty_slot) {
1548 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1549 string_len = o->length - string_start;
1550 if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
1551 debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
1552 /* list[n] points to string_start, make space for 16 more pointers */
1553 o->maxlen += 0x10 * sizeof(list[0]);
1554 o->data = xrealloc(o->data, o->maxlen + 1);
1555 list = (char**)o->data;
1556 memmove(list + n + 0x10, list + n, string_len);
1557 o->length += 0x10 * sizeof(list[0]);
1559 debug_printf_list("list[%d]=%d string_start=%d\n",
1560 n, string_len, string_start);
1563 /* We have empty slot at list[n], reuse without growth */
1564 string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
1565 string_len = o->length - string_start;
1566 debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n",
1567 n, string_len, string_start);
1568 o->has_empty_slot = 0;
1570 list[n] = (char*)(ptrdiff_t)string_len;
1574 /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
1575 static int o_get_last_ptr(o_string *o, int n)
1577 char **list = (char**)o->data;
1578 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1580 return ((int)(ptrdiff_t)list[n-1]) + string_start;
1583 /* o_glob performs globbing on last list[], saving each result
1584 * as a new list[]. */
1585 static int o_glob(o_string *o, int n)
1591 debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
1593 return o_save_ptr_helper(o, n);
1594 pattern = o->data + o_get_last_ptr(o, n);
1595 debug_printf_glob("glob pattern '%s'\n", pattern);
1596 if (!glob_needed(pattern)) {
1598 o->length = unbackslash(pattern) - o->data;
1599 debug_printf_glob("glob pattern '%s' is literal\n", pattern);
1600 return o_save_ptr_helper(o, n);
1603 memset(&globdata, 0, sizeof(globdata));
1604 gr = glob(pattern, 0, NULL, &globdata);
1605 debug_printf_glob("glob('%s'):%d\n", pattern, gr);
1606 if (gr == GLOB_NOSPACE)
1607 bb_error_msg_and_die("out of memory during glob");
1608 if (gr == GLOB_NOMATCH) {
1609 globfree(&globdata);
1612 if (gr != 0) { /* GLOB_ABORTED ? */
1613 //TODO: testcase for bad glob pattern behavior
1614 bb_error_msg("glob(3) error %d on '%s'", gr, pattern);
1616 if (globdata.gl_pathv && globdata.gl_pathv[0]) {
1617 char **argv = globdata.gl_pathv;
1618 o->length = pattern - o->data; /* "forget" pattern */
1620 o_addstr_with_NUL(o, *argv);
1621 n = o_save_ptr_helper(o, n);
1627 globfree(&globdata);
1629 debug_print_list("o_glob returning", o, n);
1633 /* If o->o_glob == 1, glob the string so far remembered.
1634 * Otherwise, just finish current list[] and start new */
1635 static int o_save_ptr(o_string *o, int n)
1637 if (o->o_glob) { /* if globbing is requested */
1638 /* If o->has_empty_slot, list[n] was already globbed
1639 * (if it was requested back then when it was filled)
1640 * so don't do that again! */
1641 if (!o->has_empty_slot)
1642 return o_glob(o, n); /* o_save_ptr_helper is inside */
1644 return o_save_ptr_helper(o, n);
1647 /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
1648 static char **o_finalize_list(o_string *o, int n)
1653 n = o_save_ptr(o, n); /* force growth for list[n] if necessary */
1655 debug_print_list("finalized", o, n);
1656 debug_printf_expand("finalized n:%d\n", n);
1657 list = (char**)o->data;
1658 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1662 list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start;
1668 /* Expansion can recurse */
1669 #if ENABLE_HUSH_TICK
1670 static int process_command_subs(o_string *dest, const char *s);
1672 static char *expand_string_to_string(const char *str);
1674 #define parse_stream_dquoted(ctx, dest, input, dquote_end) \
1675 parse_stream_dquoted(dest, input, dquote_end)
1677 static int parse_stream_dquoted(struct parse_context *ctx,
1679 struct in_str *input,
1682 /* expand_strvec_to_strvec() takes a list of strings, expands
1683 * all variable references within and returns a pointer to
1684 * a list of expanded strings, possibly with larger number
1685 * of strings. (Think VAR="a b"; echo $VAR).
1686 * This new list is allocated as a single malloc block.
1687 * NULL-terminated list of char* pointers is at the beginning of it,
1688 * followed by strings themself.
1689 * Caller can deallocate entire list by single free(list). */
1691 /* Store given string, finalizing the word and starting new one whenever
1692 * we encounter IFS char(s). This is used for expanding variable values.
1693 * End-of-string does NOT finalize word: think about 'echo -$VAR-' */
1694 static int expand_on_ifs(o_string *output, int n, const char *str)
1697 int word_len = strcspn(str, G.ifs);
1699 if (output->o_escape || !output->o_glob)
1700 o_addQstr(output, str, word_len);
1701 else /* protect backslashes against globbing up :) */
1702 o_addblock_duplicate_backslash(output, str, word_len);
1705 if (!*str) /* EOL - do not finalize word */
1707 o_addchr(output, '\0');
1708 debug_print_list("expand_on_ifs", output, n);
1709 n = o_save_ptr(output, n);
1710 str += strspn(str, G.ifs); /* skip ifs chars */
1712 debug_print_list("expand_on_ifs[1]", output, n);
1716 /* Expand all variable references in given string, adding words to list[]
1717 * at n, n+1,... positions. Return updated n (so that list[n] is next one
1718 * to be filled). This routine is extremely tricky: has to deal with
1719 * variables/parameters with whitespace, $* and $@, and constructs like
1720 * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
1721 static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
1723 /* or_mask is either 0 (normal case) or 0x80
1724 * (expansion of right-hand side of assignment == 1-element expand.
1725 * It will also do no globbing, and thus we must not backslash-quote!) */
1727 char first_ch, ored_ch;
1734 debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
1735 debug_print_list("expand_vars_to_list", output, n);
1736 n = o_save_ptr(output, n);
1737 debug_print_list("expand_vars_to_list[0]", output, n);
1739 while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
1740 #if ENABLE_HUSH_TICK
1741 o_string subst_result = NULL_O_STRING;
1743 #if ENABLE_SH_MATH_SUPPORT
1744 char arith_buf[sizeof(arith_t)*3 + 2];
1746 o_addblock(output, arg, p - arg);
1747 debug_print_list("expand_vars_to_list[1]", output, n);
1749 p = strchr(p, SPECIAL_VAR_SYMBOL);
1751 first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
1752 /* "$@" is special. Even if quoted, it can still
1753 * expand to nothing (not even an empty string) */
1754 if ((first_ch & 0x7f) != '@')
1755 ored_ch |= first_ch;
1758 switch (first_ch & 0x7f) {
1759 /* Highest bit in first_ch indicates that var is double-quoted */
1761 val = utoa(G.root_pid);
1763 case '!': /* bg pid */
1764 val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)"";
1766 case '?': /* exitcode */
1767 val = utoa(G.last_return_code);
1769 case '#': /* argc */
1770 if (arg[1] != SPECIAL_VAR_SYMBOL)
1771 /* actually, it's a ${#var} */
1773 val = utoa(G.global_argc ? G.global_argc-1 : 0);
1778 if (!G.global_argv[i])
1780 ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
1781 if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
1782 smallint sv = output->o_escape;
1783 /* unquoted var's contents should be globbed, so don't escape */
1784 output->o_escape = 0;
1785 while (G.global_argv[i]) {
1786 n = expand_on_ifs(output, n, G.global_argv[i]);
1787 debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
1788 if (G.global_argv[i++][0] && G.global_argv[i]) {
1789 /* this argv[] is not empty and not last:
1790 * put terminating NUL, start new word */
1791 o_addchr(output, '\0');
1792 debug_print_list("expand_vars_to_list[2]", output, n);
1793 n = o_save_ptr(output, n);
1794 debug_print_list("expand_vars_to_list[3]", output, n);
1797 output->o_escape = sv;
1799 /* If or_mask is nonzero, we handle assignment 'a=....$@.....'
1800 * and in this case should treat it like '$*' - see 'else...' below */
1801 if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */
1803 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1804 if (++i >= G.global_argc)
1806 o_addchr(output, '\0');
1807 debug_print_list("expand_vars_to_list[4]", output, n);
1808 n = o_save_ptr(output, n);
1810 } else { /* quoted $*: add as one word */
1812 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1813 if (!G.global_argv[++i])
1816 o_addchr(output, G.ifs[0]);
1820 case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
1821 /* "Empty variable", used to make "" etc to not disappear */
1825 #if ENABLE_HUSH_TICK
1826 case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
1829 //TODO: can we just stuff it into "output" directly?
1830 debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
1831 process_command_subs(&subst_result, arg);
1832 debug_printf_subst("SUBST RES '%s'\n", subst_result.data);
1833 val = subst_result.data;
1836 #if ENABLE_SH_MATH_SUPPORT
1837 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
1838 arith_eval_hooks_t hooks;
1843 arg++; /* skip '+' */
1844 *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
1845 debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
1847 /* Optional: skip expansion if expr is simple ("a + 3", "i++" etc) */
1850 unsigned char c = *exp_str++;
1857 if (strchr(" \t+-*/%_", c) != NULL)
1859 c |= 0x20; /* tolower */
1860 if (c >= 'a' && c <= 'z')
1864 /* We need to expand. Example: "echo $(($a + 1)) $((1 + $((2)) ))" */
1866 struct in_str input;
1867 o_string dest = NULL_O_STRING;
1869 setup_string_in_str(&input, arg);
1870 parse_stream_dquoted(NULL, &dest, &input, EOF);
1871 //bb_error_msg("'%s' -> '%s'", arg, dest.data);
1872 exp_str = expand_string_to_string(dest.data);
1873 //bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
1877 hooks.lookupvar = get_local_var_value;
1878 hooks.setvar = arith_set_local_var;
1879 hooks.endofname = endofname;
1880 res = arith(exp_str ? exp_str : arg, &errcode, &hooks);
1885 case -3: maybe_die("arith", "exponent less than 0"); break;
1886 case -2: maybe_die("arith", "divide by zero"); break;
1887 case -5: maybe_die("arith", "expression recursion loop detected"); break;
1888 default: maybe_die("arith", "syntax error"); break;
1891 debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
1892 sprintf(arith_buf, arith_t_fmt, res);
1897 default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
1899 bool exp_len = false, exp_null = false;
1900 char *var = arg, exp_save, exp_op, *exp_word;
1903 arg[0] = first_ch & 0x7f;
1905 /* prepare for expansions */
1906 if (var[0] == '#') {
1907 /* handle length expansion ${#var} */
1911 /* maybe handle parameter expansion */
1912 exp_off = strcspn(var, ":-=+?");
1916 exp_save = var[exp_off];
1917 exp_null = exp_save == ':';
1918 exp_word = var + exp_off;
1919 if (exp_null) ++exp_word;
1920 exp_op = *exp_word++;
1921 var[exp_off] = '\0';
1925 /* lookup the variable in question */
1926 if (isdigit(var[0])) {
1927 /* handle_dollar() should have vetted var for us */
1929 if (i < G.global_argc)
1930 val = G.global_argv[i];
1931 /* else val remains NULL: $N with too big N */
1933 val = get_local_var_value(var);
1935 /* handle any expansions */
1937 debug_printf_expand("expand: length of '%s' = ", val);
1938 val = utoa(val ? strlen(val) : 0);
1939 debug_printf_expand("%s\n", val);
1940 } else if (exp_off) {
1941 /* we need to do an expansion */
1942 int exp_test = (!val || (exp_null && !val[0]));
1944 exp_test = !exp_test;
1945 debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
1946 exp_null ? "true" : "false", exp_test);
1949 maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
1953 if (exp_op == '=') {
1954 if (isdigit(var[0]) || var[0] == '#') {
1955 maybe_die(var, "special vars cannot assign in this way");
1958 char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
1959 sprintf(new_var, "%s=%s", var, val);
1960 set_local_var(new_var, -1, 0);
1964 var[exp_off] = exp_save;
1968 #if ENABLE_HUSH_TICK
1971 if (!(first_ch & 0x80)) { /* unquoted $VAR */
1972 debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape);
1974 /* unquoted var's contents should be globbed, so don't escape */
1975 smallint sv = output->o_escape;
1976 output->o_escape = 0;
1977 n = expand_on_ifs(output, n, val);
1979 output->o_escape = sv;
1981 } else { /* quoted $VAR, val will be appended below */
1982 debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape);
1985 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
1987 o_addQstr(output, val, strlen(val));
1989 /* Do the check to avoid writing to a const string */
1990 if (*p != SPECIAL_VAR_SYMBOL)
1991 *p = SPECIAL_VAR_SYMBOL;
1993 #if ENABLE_HUSH_TICK
1994 o_free(&subst_result);
1997 } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
2000 debug_print_list("expand_vars_to_list[a]", output, n);
2001 /* this part is literal, and it was already pre-quoted
2002 * if needed (much earlier), do not use o_addQstr here! */
2003 o_addstr_with_NUL(output, arg);
2004 debug_print_list("expand_vars_to_list[b]", output, n);
2005 } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
2006 && !(ored_ch & 0x80) /* and all vars were not quoted. */
2009 /* allow to reuse list[n] later without re-growth */
2010 output->has_empty_slot = 1;
2012 o_addchr(output, '\0');
2017 static char **expand_variables(char **argv, int or_mask)
2022 o_string output = NULL_O_STRING;
2024 if (or_mask & 0x100) {
2025 output.o_escape = 1; /* protect against globbing for "$var" */
2026 /* (unquoted $var will temporarily switch it off) */
2033 n = expand_vars_to_list(&output, n, *v, (char)or_mask);
2036 debug_print_list("expand_variables", &output, n);
2038 /* output.data (malloced in one block) gets returned in "list" */
2039 list = o_finalize_list(&output, n);
2040 debug_print_strings("expand_variables[1]", list);
2044 static char **expand_strvec_to_strvec(char **argv)
2046 return expand_variables(argv, 0x100);
2049 /* Used for expansion of right hand of assignments */
2050 /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs
2052 static char *expand_string_to_string(const char *str)
2054 char *argv[2], **list;
2056 argv[0] = (char*)str;
2058 list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */
2060 if (!list[0] || list[1])
2061 bb_error_msg_and_die("BUG in varexp2");
2062 /* actually, just move string 2*sizeof(char*) bytes back */
2063 overlapping_strcpy((char*)list, list[0]);
2064 debug_printf_expand("string_to_string='%s'\n", (char*)list);
2068 /* Used for "eval" builtin */
2069 static char* expand_strvec_to_string(char **argv)
2073 list = expand_variables(argv, 0x80);
2074 /* Convert all NULs to spaces */
2079 if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
2080 bb_error_msg_and_die("BUG in varexp3");
2081 list[n][-1] = ' '; /* TODO: or to G.ifs[0]? */
2085 overlapping_strcpy((char*)list, list[0]);
2086 debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
2090 static char **expand_assignments(char **argv, int count)
2094 /* Expand assignments into one string each */
2095 for (i = 0; i < count; i++) {
2096 p = add_string_to_strings(p, expand_string_to_string(argv[i]));
2102 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
2103 * and stderr if they are redirected. */
2104 static int setup_redirects(struct command *prog, int squirrel[])
2107 struct redir_struct *redir;
2109 for (redir = prog->redirects; redir; redir = redir->next) {
2110 if (redir->dup == -1 && redir->rd_filename == NULL) {
2111 /* something went wrong in the parse. Pretend it didn't happen */
2114 if (redir->dup == -1) {
2116 mode = redir_table[redir->rd_type].mode;
2117 //TODO: check redir for names like '\\'
2118 p = expand_string_to_string(redir->rd_filename);
2119 openfd = open_or_warn(p, mode);
2122 /* this could get lost if stderr has been redirected, but
2123 bash and ash both lose it as well (though zsh doesn't!) */
2127 openfd = redir->dup;
2130 if (openfd != redir->fd) {
2131 if (squirrel && redir->fd < 3) {
2132 squirrel[redir->fd] = dup(redir->fd);
2135 //close(openfd); // close(-3) ??!
2137 dup2(openfd, redir->fd);
2138 if (redir->dup == -1)
2146 static void restore_redirects(int squirrel[])
2149 for (i = 0; i < 3; i++) {
2152 /* We simply die on error */
2159 #if !defined(DEBUG_CLEAN)
2160 #define free_pipe_list(head, indent) free_pipe_list(head)
2161 #define free_pipe(pi, indent) free_pipe(pi)
2163 static void free_pipe_list(struct pipe *head, int indent);
2165 /* Return code is the exit status of the pipe */
2166 static void free_pipe(struct pipe *pi, int indent)
2169 struct command *command;
2170 struct redir_struct *r, *rnext;
2173 if (pi->stopped_cmds > 0) /* why? */
2175 debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
2176 for (i = 0; i < pi->num_cmds; i++) {
2177 command = &pi->cmds[i];
2178 debug_printf_clean("%s command %d:\n", indenter(indent), i);
2179 if (command->argv) {
2180 for (a = 0, p = command->argv; *p; a++, p++) {
2181 debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p);
2183 free_strings(command->argv);
2184 command->argv = NULL;
2186 /* not "else if": on syntax error, we may have both! */
2187 if (command->group) {
2188 debug_printf_clean("%s begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
2189 free_pipe_list(command->group, indent+3);
2190 debug_printf_clean("%s end group\n", indenter(indent));
2191 command->group = NULL;
2194 free(command->group_as_string);
2195 command->group_as_string = NULL;
2197 for (r = command->redirects; r; r = rnext) {
2198 debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->rd_type].descrip);
2200 /* guard against the case >$FOO, where foo is unset or blank */
2201 if (r->rd_filename) {
2202 debug_printf_clean(" %s\n", r->rd_filename);
2203 free(r->rd_filename);
2204 r->rd_filename = NULL;
2207 debug_printf_clean("&%d\n", r->dup);
2212 command->redirects = NULL;
2214 free(pi->cmds); /* children are an array, they get freed all at once */
2222 static void free_pipe_list(struct pipe *head, int indent)
2224 struct pipe *pi, *next;
2226 for (pi = head; pi; pi = next) {
2228 debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word);
2230 free_pipe(pi, indent);
2231 debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup);
2233 /*pi->next = NULL;*/
2240 typedef struct nommu_save_t {
2246 #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
2247 pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
2248 #define pseudo_exec(nommu_save, command, argv_expanded) \
2249 pseudo_exec(command, argv_expanded)
2252 /* Called after [v]fork() in run_pipe(), or from builtin_exec().
2254 * XXX no exit() here. If you don't exec, use _exit instead.
2255 * The at_exit handlers apparently confuse the calling process,
2256 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
2257 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2258 char **argv, int assignment_cnt,
2259 char **argv_expanded) NORETURN;
2260 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2261 char **argv, int assignment_cnt,
2262 char **argv_expanded)
2266 /* Case when we are here: ... | var=val | ... */
2267 if (!argv[assignment_cnt])
2268 _exit(EXIT_SUCCESS);
2270 new_env = expand_assignments(argv, assignment_cnt);
2272 putenv_all(new_env);
2273 free(new_env); /* optional */
2275 nommu_save->new_env = new_env;
2276 nommu_save->old_env = putenv_all_and_save_old(new_env);
2278 if (argv_expanded) {
2279 argv = argv_expanded;
2281 argv = expand_strvec_to_strvec(argv + assignment_cnt);
2283 nommu_save->argv = argv;
2287 /* On NOMMU, we must never block!
2288 * Example: { sleep 99999 | read line } & echo Ok
2289 * read builtin will block on read syscall, leaving parent blocked
2290 * in vfork. Therefore we can't do this:
2293 /* Check if the command matches any of the builtins.
2294 * Depending on context, this might be redundant. But it's
2295 * easier to waste a few CPU cycles than it is to figure out
2296 * if this is one of those cases.
2300 const struct built_in_command *x;
2301 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2302 if (strcmp(argv[0], x->cmd) == 0) {
2303 debug_printf_exec("running builtin '%s'\n",
2305 rcode = x->function(argv);
2313 #if ENABLE_FEATURE_SH_STANDALONE
2314 /* Check if the command matches any busybox applets */
2315 if (strchr(argv[0], '/') == NULL) {
2316 int a = find_applet_by_name(argv[0]);
2318 #if BB_MMU /* see above why on NOMMU it is not allowed */
2319 if (APPLET_IS_NOEXEC(a)) {
2320 debug_printf_exec("running applet '%s'\n", argv[0]);
2321 run_applet_no_and_exit(a, argv);
2324 /* Re-exec ourselves */
2325 debug_printf_exec("re-execing applet '%s'\n", argv[0]);
2326 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2327 execv(bb_busybox_exec_path, argv);
2328 /* If they called chroot or otherwise made the binary no longer
2329 * executable, fall through */
2334 debug_printf_exec("execing '%s'\n", argv[0]);
2335 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2336 execvp(argv[0], argv);
2337 bb_perror_msg("can't exec '%s'", argv[0]);
2338 _exit(EXIT_FAILURE);
2341 static void re_execute_shell(const char *s) NORETURN;
2342 static void re_execute_shell(const char *s)
2344 struct variable *cur;
2348 /* hush -$<pid> -?<exitcode> ... -c <cmd> NULL */
2350 for (cur = G.top_var; cur; cur = cur->next) {
2351 if (!cur->flg_export || cur->flg_read_only)
2354 //TODO: need to free these strings in parent!
2355 argv = pp = xmalloc(sizeof(argv[0]) * cnt);
2356 *pp++ = (char *) applet_name;
2357 *pp++ = xasprintf("-$%u", G.root_pid);
2358 *pp++ = xasprintf("-?%u", G.last_return_code);
2359 for (cur = G.top_var; cur; cur = cur->next) {
2360 if (cur->varstr == hush_version_str)
2362 if (cur->flg_read_only) {
2363 *pp++ = (char *) "-R";
2364 *pp++ = cur->varstr;
2365 } else if (!cur->flg_export) {
2366 *pp++ = (char *) "-V";
2367 *pp++ = cur->varstr;
2370 *pp++ = (char *) "-c";
2374 //TODO: pass traps and functions
2376 debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
2377 execv(bb_busybox_exec_path, argv);
2378 //TODO: fallback for init=/bin/hush?
2382 static int run_list(struct pipe *pi);
2384 /* Called after [v]fork() in run_pipe()
2386 static void pseudo_exec(nommu_save_t *nommu_save,
2387 struct command *command,
2388 char **argv_expanded) NORETURN;
2389 static void pseudo_exec(nommu_save_t *nommu_save,
2390 struct command *command,
2391 char **argv_expanded)
2393 if (command->argv) {
2394 pseudo_exec_argv(nommu_save, command->argv,
2395 command->assignment_cnt, argv_expanded);
2398 if (command->group) {
2399 /* Cases when we are here:
2402 * ... | ( list ) | ...
2403 * ... | { list } | ...
2407 debug_printf_exec("pseudo_exec: run_list\n");
2408 rcode = run_list(command->group);
2409 /* OK to leak memory by not calling free_pipe_list,
2410 * since this process is about to exit */
2413 re_execute_shell(command->group_as_string);
2417 /* Case when we are here: ... | >file */
2418 debug_printf_exec("pseudo_exec'ed null command\n");
2419 _exit(EXIT_SUCCESS);
2423 static const char *get_cmdtext(struct pipe *pi)
2429 /* This is subtle. ->cmdtext is created only on first backgrounding.
2430 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
2431 * On subsequent bg argv is trashed, but we won't use it */
2434 argv = pi->cmds[0].argv;
2435 if (!argv || !argv[0]) {
2436 pi->cmdtext = xzalloc(1);
2441 do len += strlen(*argv) + 1; while (*++argv);
2442 pi->cmdtext = p = xmalloc(len);
2443 argv = pi->cmds[0].argv;
2445 len = strlen(*argv);
2446 memcpy(p, *argv, len);
2454 static void insert_bg_job(struct pipe *pi)
2456 struct pipe *thejob;
2459 /* Linear search for the ID of the job to use */
2461 for (thejob = G.job_list; thejob; thejob = thejob->next)
2462 if (thejob->jobid >= pi->jobid)
2463 pi->jobid = thejob->jobid + 1;
2465 /* Add thejob to the list of running jobs */
2467 thejob = G.job_list = xmalloc(sizeof(*thejob));
2469 for (thejob = G.job_list; thejob->next; thejob = thejob->next)
2471 thejob->next = xmalloc(sizeof(*thejob));
2472 thejob = thejob->next;
2475 /* Physically copy the struct job */
2476 memcpy(thejob, pi, sizeof(struct pipe));
2477 thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
2478 /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */
2479 for (i = 0; i < pi->num_cmds; i++) {
2480 // TODO: do we really need to have so many fields which are just dead weight
2481 // at execution stage?
2482 thejob->cmds[i].pid = pi->cmds[i].pid;
2483 /* all other fields are not used and stay zero */
2485 thejob->next = NULL;
2486 thejob->cmdtext = xstrdup(get_cmdtext(pi));
2488 /* We don't wait for background thejobs to return -- append it
2489 to the list of backgrounded thejobs and leave it alone */
2490 if (G_interactive_fd)
2491 printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext);
2492 G.last_bg_pid = thejob->cmds[0].pid;
2493 G.last_jobid = thejob->jobid;
2496 static void remove_bg_job(struct pipe *pi)
2498 struct pipe *prev_pipe;
2500 if (pi == G.job_list) {
2501 G.job_list = pi->next;
2503 prev_pipe = G.job_list;
2504 while (prev_pipe->next != pi)
2505 prev_pipe = prev_pipe->next;
2506 prev_pipe->next = pi->next;
2509 G.last_jobid = G.job_list->jobid;
2514 /* Remove a backgrounded job */
2515 static void delete_finished_bg_job(struct pipe *pi)
2518 pi->stopped_cmds = 0;
2524 /* Check to see if any processes have exited -- if they
2525 * have, figure out why and see if a job has completed */
2526 static int checkjobs(struct pipe* fg_pipe)
2536 debug_printf_jobs("checkjobs %p\n", fg_pipe);
2539 // if (G.handled_SIGCHLD == G.count_SIGCHLD)
2540 // /* avoid doing syscall, nothing there anyway */
2543 attributes = WUNTRACED;
2544 if (fg_pipe == NULL)
2545 attributes |= WNOHANG;
2547 /* Do we do this right?
2548 * bash-3.00# sleep 20 | false
2550 * [3]+ Stopped sleep 20 | false
2551 * bash-3.00# echo $?
2552 * 1 <========== bg pipe is not fully done, but exitcode is already known!
2555 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
2556 //are stopped. Testcase: "cat | cat" in a script (not on command line)
2557 // + killall -STOP cat
2564 // i = G.count_SIGCHLD;
2565 childpid = waitpid(-1, &status, attributes);
2566 if (childpid <= 0) {
2567 if (childpid && errno != ECHILD)
2568 bb_perror_msg("waitpid");
2569 // else /* Until next SIGCHLD, waitpid's are useless */
2570 // G.handled_SIGCHLD = i;
2573 dead = WIFEXITED(status) || WIFSIGNALED(status);
2576 if (WIFSTOPPED(status))
2577 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
2578 childpid, WSTOPSIG(status), WEXITSTATUS(status));
2579 if (WIFSIGNALED(status))
2580 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
2581 childpid, WTERMSIG(status), WEXITSTATUS(status));
2582 if (WIFEXITED(status))
2583 debug_printf_jobs("pid %d exited, exitcode %d\n",
2584 childpid, WEXITSTATUS(status));
2586 /* Were we asked to wait for fg pipe? */
2588 for (i = 0; i < fg_pipe->num_cmds; i++) {
2589 debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
2590 if (fg_pipe->cmds[i].pid != childpid)
2592 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
2594 fg_pipe->cmds[i].pid = 0;
2595 fg_pipe->alive_cmds--;
2596 if (i == fg_pipe->num_cmds - 1) {
2597 /* last process gives overall exitstatus */
2598 rcode = WEXITSTATUS(status);
2599 IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
2602 fg_pipe->cmds[i].is_stopped = 1;
2603 fg_pipe->stopped_cmds++;
2605 debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
2606 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
2607 if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) {
2608 /* All processes in fg pipe have exited/stopped */
2610 if (fg_pipe->alive_cmds)
2611 insert_bg_job(fg_pipe);
2615 /* There are still running processes in the fg pipe */
2616 goto wait_more; /* do waitpid again */
2618 /* it wasnt fg_pipe, look for process in bg pipes */
2622 /* We asked to wait for bg or orphaned children */
2623 /* No need to remember exitcode in this case */
2624 for (pi = G.job_list; pi; pi = pi->next) {
2625 for (i = 0; i < pi->num_cmds; i++) {
2626 if (pi->cmds[i].pid == childpid)
2627 goto found_pi_and_prognum;
2630 /* Happens when shell is used as init process (init=/bin/sh) */
2631 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
2632 continue; /* do waitpid again */
2634 found_pi_and_prognum:
2637 pi->cmds[i].pid = 0;
2639 if (!pi->alive_cmds) {
2640 if (G_interactive_fd)
2641 printf(JOB_STATUS_FORMAT, pi->jobid,
2642 "Done", pi->cmdtext);
2643 delete_finished_bg_job(pi);
2647 pi->cmds[i].is_stopped = 1;
2651 } /* while (waitpid succeeds)... */
2657 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
2660 int rcode = checkjobs(fg_pipe);
2661 /* Job finished, move the shell to the foreground */
2662 p = getpgid(0); /* pgid of our process */
2663 debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
2664 tcsetpgrp(G_interactive_fd, p);
2669 /* Start all the jobs, but don't wait for anything to finish.
2672 * Return code is normally -1, when the caller has to wait for children
2673 * to finish to determine the exit status of the pipe. If the pipe
2674 * is a simple builtin command, however, the action is done by the
2675 * time run_pipe returns, and the exit code is provided as the
2678 * Returns -1 only if started some children. IOW: we have to
2679 * mask out retvals of builtins etc with 0xff!
2681 * The only case when we do not need to [v]fork is when the pipe
2682 * is single, non-backgrounded, non-subshell command. Examples:
2683 * cmd ; ... { list } ; ...
2684 * cmd && ... { list } && ...
2685 * cmd || ... { list } || ...
2686 * If it is, then we can run cmd as a builtin, NOFORK [do we do this?],
2687 * or (if SH_STANDALONE) an applet, and we can run the { list }
2688 * with run_list(). If it isn't one of these, we fork and exec cmd.
2690 * Cases when we must fork:
2691 * non-single: cmd | cmd
2692 * backgrounded: cmd & { list } &
2693 * subshell: ( list ) [&]
2695 static int run_pipe(struct pipe *pi)
2697 static const char *const null_ptr = NULL;
2700 int pipefds[2]; /* pipefds[0] is for reading */
2701 struct command *command;
2702 char **argv_expanded;
2705 /* it is not always needed, but we aim to smaller code */
2706 int squirrel[] = { -1, -1, -1 };
2709 debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
2711 USE_HUSH_JOB(pi->pgrp = -1;)
2712 pi->stopped_cmds = 0;
2713 command = &(pi->cmds[0]);
2714 argv_expanded = NULL;
2716 if (pi->num_cmds != 1
2717 || pi->followup == PIPE_BG
2718 || command->grp_type == GRP_SUBSHELL
2725 debug_printf_exec(": group:%p argv:'%s'\n",
2726 command->group, command->argv ? command->argv[0] : "NONE");
2728 if (command->group) {
2729 #if ENABLE_HUSH_FUNCTIONS
2730 if (command->grp_type == GRP_FUNCTION) {
2731 /* func () { list } */
2732 bb_error_msg("here we ought to remember function definition, and go on");
2733 return EXIT_SUCCESS;
2737 debug_printf("non-subshell group\n");
2738 setup_redirects(command, squirrel);
2739 debug_printf_exec(": run_list\n");
2740 rcode = run_list(command->group) & 0xff;
2741 restore_redirects(squirrel);
2742 debug_printf_exec("run_pipe return %d\n", rcode);
2743 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2747 argv = command->argv ? command->argv : (char **) &null_ptr;
2749 const struct built_in_command *x;
2750 char **new_env = NULL;
2751 char **old_env = NULL;
2753 if (argv[command->assignment_cnt] == NULL) {
2754 /* Assignments, but no command */
2755 /* Ensure redirects take effect. Try "a=t >file" */
2756 setup_redirects(command, squirrel);
2757 restore_redirects(squirrel);
2758 /* Set shell variables */
2760 p = expand_string_to_string(*argv);
2761 debug_printf_exec("set shell var:'%s'->'%s'\n",
2763 set_local_var(p, 0, 0);
2766 /* Do we need to flag set_local_var() errors?
2767 * "assignment to readonly var" and "putenv error"
2769 return EXIT_SUCCESS;
2772 /* Expand the rest into (possibly) many strings each */
2773 argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
2775 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2776 if (strcmp(argv_expanded[0], x->cmd) != 0)
2778 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
2779 debug_printf("exec with redirects only\n");
2780 setup_redirects(command, NULL);
2781 rcode = EXIT_SUCCESS;
2782 goto clean_up_and_ret1;
2784 debug_printf("builtin inline %s\n", argv_expanded[0]);
2785 /* XXX setup_redirects acts on file descriptors, not FILEs.
2786 * This is perfect for work that comes after exec().
2787 * Is it really safe for inline use? Experimentally,
2788 * things seem to work with glibc. */
2789 setup_redirects(command, squirrel);
2790 new_env = expand_assignments(argv, command->assignment_cnt);
2791 old_env = putenv_all_and_save_old(new_env);
2792 debug_printf_exec(": builtin '%s' '%s'...\n",
2793 x->cmd, argv_expanded[1]);
2794 rcode = x->function(argv_expanded) & 0xff;
2795 #if ENABLE_FEATURE_SH_STANDALONE
2798 restore_redirects(squirrel);
2799 free_strings_and_unsetenv(new_env, 1);
2800 putenv_all(old_env);
2801 free(old_env); /* not free_strings()! */
2803 free(argv_expanded);
2804 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2805 debug_printf_exec("run_pipe return %d\n", rcode);
2808 #if ENABLE_FEATURE_SH_STANDALONE
2809 i = find_applet_by_name(argv_expanded[0]);
2810 if (i >= 0 && APPLET_IS_NOFORK(i)) {
2811 setup_redirects(command, squirrel);
2812 save_nofork_data(&G.nofork_save);
2813 new_env = expand_assignments(argv, command->assignment_cnt);
2814 old_env = putenv_all_and_save_old(new_env);
2815 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
2816 argv_expanded[0], argv_expanded[1]);
2817 rcode = run_nofork_applet_prime(&G.nofork_save, i, argv_expanded);
2818 goto clean_up_and_ret;
2821 /* It is neither builtin nor applet. We must fork. */
2825 /* NB: argv_expanded may already be created, and that
2826 * might include `cmd` runs! Do not rerun it! We *must*
2827 * use argv_expanded if it's non-NULL */
2829 /* Going to fork a child per each pipe member */
2833 for (i = 0; i < pi->num_cmds; i++) {
2835 volatile nommu_save_t nommu_save;
2836 nommu_save.new_env = NULL;
2837 nommu_save.old_env = NULL;
2838 nommu_save.argv = NULL;
2840 command = &(pi->cmds[i]);
2841 if (command->argv) {
2842 debug_printf_exec(": pipe member '%s' '%s'...\n",
2843 command->argv[0], command->argv[1]);
2845 debug_printf_exec(": pipe member with no argv\n");
2848 /* pipes are inserted between pairs of commands */
2851 if ((i + 1) < pi->num_cmds)
2854 command->pid = BB_MMU ? fork() : vfork();
2855 if (!command->pid) { /* child */
2857 die_sleep = 0; /* let nofork's xfuncs die */
2859 /* Every child adds itself to new process group
2860 * with pgid == pid_of_first_child_in_pipe */
2861 if (G.run_list_level == 1 && G_interactive_fd) {
2864 if (pgrp < 0) /* true for 1st process only */
2866 if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
2867 /* We do it in *every* child, not just first,
2869 tcsetpgrp(G_interactive_fd, pgrp);
2873 xmove_fd(nextin, 0);
2874 xmove_fd(pipefds[1], 1); /* write end */
2876 close(pipefds[0]); /* read end */
2877 /* Like bash, explicit redirects override pipes,
2878 * and the pipe fd is available for dup'ing. */
2879 setup_redirects(command, NULL);
2881 /* Restore default handlers just prior to exec */
2882 /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
2884 /* Stores to nommu_save list of env vars putenv'ed
2885 * (NOMMU, on MMU we don't need that) */
2886 /* cast away volatility... */
2887 pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
2888 /* pseudo_exec() does not return */
2892 /* Clean up after vforked child */
2893 free(nommu_save.argv);
2894 free_strings_and_unsetenv(nommu_save.new_env, 1);
2895 putenv_all(nommu_save.old_env);
2897 free(argv_expanded);
2898 argv_expanded = NULL;
2899 if (command->pid < 0) { /* [v]fork failed */
2900 /* Clearly indicate, was it fork or vfork */
2901 bb_perror_msg(BB_MMU ? "fork" : "vfork");
2905 /* Second and next children need to know pid of first one */
2907 pi->pgrp = command->pid;
2913 if ((i + 1) < pi->num_cmds)
2914 close(pipefds[1]); /* write end */
2915 /* Pass read (output) pipe end to next iteration */
2916 nextin = pipefds[0];
2919 if (!pi->alive_cmds) {
2920 debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
2924 debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
2928 #ifndef debug_print_tree
2929 static void debug_print_tree(struct pipe *pi, int lvl)
2931 static const char *const PIPE[] = {
2937 static const char *RES[] = {
2938 [RES_NONE ] = "NONE" ,
2941 [RES_THEN ] = "THEN" ,
2942 [RES_ELIF ] = "ELIF" ,
2943 [RES_ELSE ] = "ELSE" ,
2946 #if ENABLE_HUSH_LOOPS
2947 [RES_FOR ] = "FOR" ,
2948 [RES_WHILE] = "WHILE",
2949 [RES_UNTIL] = "UNTIL",
2951 [RES_DONE ] = "DONE" ,
2953 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
2956 #if ENABLE_HUSH_CASE
2957 [RES_CASE ] = "CASE" ,
2958 [RES_MATCH] = "MATCH",
2959 [RES_CASEI] = "CASEI",
2960 [RES_ESAC ] = "ESAC" ,
2962 [RES_XXXX ] = "XXXX" ,
2963 [RES_SNTX ] = "SNTX" ,
2965 static const char *const GRPTYPE[] = {
2968 #if ENABLE_HUSH_FUNCTIONS
2977 fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
2978 pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
2980 while (prn < pi->num_cmds) {
2981 struct command *command = &pi->cmds[prn];
2982 char **argv = command->argv;
2984 fprintf(stderr, "%*s prog %d assignment_cnt:%d",
2986 command->assignment_cnt);
2987 if (command->group) {
2988 fprintf(stderr, " group %s: (argv=%p)\n",
2989 GRPTYPE[command->grp_type],
2991 debug_print_tree(command->group, lvl+1);
2995 if (argv) while (*argv) {
2996 fprintf(stderr, " '%s'", *argv);
2999 fprintf(stderr, "\n");
3008 /* NB: called by pseudo_exec, and therefore must not modify any
3009 * global data until exec/_exit (we can be a child after vfork!) */
3010 static int run_list(struct pipe *pi)
3012 #if ENABLE_HUSH_CASE
3013 char *case_word = NULL;
3015 #if ENABLE_HUSH_LOOPS
3016 struct pipe *loop_top = NULL;
3017 char *for_varname = NULL;
3018 char **for_lcur = NULL;
3019 char **for_list = NULL;
3021 smallint flag_skip = 1;
3022 smalluint rcode = 0; /* probably just for compiler */
3023 #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
3024 smalluint cond_code = 0;
3026 enum { cond_code = 0, };
3028 /*enum reserved_style*/ smallint rword = RES_NONE;
3029 /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
3031 debug_printf_exec("run_list start lvl %d\n", G.run_list_level + 1);
3033 #if ENABLE_HUSH_LOOPS
3034 /* Check syntax for "for" */
3035 for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
3036 if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
3038 /* current word is FOR or IN (BOLD in comments below) */
3039 if (cpipe->next == NULL) {
3040 syntax("malformed for");
3041 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3044 /* "FOR v; do ..." and "for v IN a b; do..." are ok */
3045 if (cpipe->next->res_word == RES_DO)
3047 /* next word is not "do". It must be "in" then ("FOR v in ...") */
3048 if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
3049 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
3051 syntax("malformed for");
3052 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3058 /* Past this point, all code paths should jump to ret: label
3059 * in order to return, no direct "return" statements please.
3060 * This helps to ensure that no memory is leaked. */
3062 ////TODO: ctrl-Z handling needs re-thinking and re-testing
3065 /* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
3066 * We are saving state before entering outermost list ("while...done")
3067 * so that ctrl-Z will correctly background _entire_ outermost list,
3068 * not just a part of it (like "sleep 1 | exit 2") */
3069 if (++G.run_list_level == 1 && G_interactive_fd) {
3070 if (sigsetjmp(G.toplevel_jb, 1)) {
3071 /* ctrl-Z forked and we are parent; or ctrl-C.
3072 * Sighandler has longjmped us here */
3073 signal(SIGINT, SIG_IGN);
3074 signal(SIGTSTP, SIG_IGN);
3075 /* Restore level (we can be coming from deep inside
3077 G.run_list_level = 1;
3078 #if ENABLE_FEATURE_SH_STANDALONE
3079 if (G.nofork_save.saved) { /* if save area is valid */
3080 debug_printf_jobs("exiting nofork early\n");
3081 restore_nofork_data(&G.nofork_save);
3084 //// if (G.ctrl_z_flag) {
3085 //// /* ctrl-Z has forked and stored pid of the child in pi->pid.
3086 //// * Remember this child as background job */
3087 //// insert_bg_job(pi);
3089 /* ctrl-C. We just stop doing whatever we were doing */
3092 USE_HUSH_LOOPS(loop_top = NULL;)
3093 USE_HUSH_LOOPS(G.depth_of_loop = 0;)
3097 //// /* ctrl-Z handler will store pid etc in pi */
3098 //// G.toplevel_list = pi;
3099 //// G.ctrl_z_flag = 0;
3100 ////#if ENABLE_FEATURE_SH_STANDALONE
3101 //// G.nofork_save.saved = 0; /* in case we will run a nofork later */
3103 //// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
3104 //// signal(SIGINT, handler_ctrl_c);
3108 /* Go through list of pipes, (maybe) executing them. */
3109 for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
3113 IF_HAS_KEYWORDS(rword = pi->res_word;)
3114 IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
3115 debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
3116 rword, cond_code, skip_more_for_this_rword);
3117 #if ENABLE_HUSH_LOOPS
3118 if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
3119 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
3121 /* start of a loop: remember where loop starts */
3126 if (rword == skip_more_for_this_rword && flag_skip) {
3127 if (pi->followup == PIPE_SEQ)
3129 /* it is "<false> && CMD" or "<true> || CMD"
3130 * and we should not execute CMD */
3134 skip_more_for_this_rword = RES_XXXX;
3137 if (rword == RES_THEN) {
3138 /* "if <false> THEN cmd": skip cmd */
3142 if (rword == RES_ELSE || rword == RES_ELIF) {
3143 /* "if <true> then ... ELSE/ELIF cmd":
3144 * skip cmd and all following ones */
3149 #if ENABLE_HUSH_LOOPS
3150 if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
3152 /* first loop through for */
3154 static const char encoded_dollar_at[] ALIGN1 = {
3155 SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
3156 }; /* encoded representation of "$@" */
3157 static const char *const encoded_dollar_at_argv[] = {
3158 encoded_dollar_at, NULL
3159 }; /* argv list with one element: "$@" */
3162 vals = (char**)encoded_dollar_at_argv;
3163 if (pi->next->res_word == RES_IN) {
3164 /* if no variable values after "in" we skip "for" */
3165 if (!pi->next->cmds[0].argv)
3167 vals = pi->next->cmds[0].argv;
3168 } /* else: "for var; do..." -> assume "$@" list */
3169 /* create list of variable values */
3170 debug_print_strings("for_list made from", vals);
3171 for_list = expand_strvec_to_strvec(vals);
3172 for_lcur = for_list;
3173 debug_print_strings("for_list", for_list);
3174 for_varname = pi->cmds[0].argv[0];
3175 pi->cmds[0].argv[0] = NULL;
3177 free(pi->cmds[0].argv[0]);
3179 /* "for" loop is over, clean up */
3183 pi->cmds[0].argv[0] = for_varname;
3186 /* insert next value from for_lcur */
3187 //TODO: does it need escaping?
3188 pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
3189 pi->cmds[0].assignment_cnt = 1;
3191 if (rword == RES_IN) {
3192 continue; /* "for v IN list;..." - "in" has no cmds anyway */
3194 if (rword == RES_DONE) {
3195 continue; /* "done" has no cmds too */
3198 #if ENABLE_HUSH_CASE
3199 if (rword == RES_CASE) {
3200 case_word = expand_strvec_to_string(pi->cmds->argv);
3203 if (rword == RES_MATCH) {
3206 if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
3208 /* all prev words didn't match, does this one match? */
3209 argv = pi->cmds->argv;
3211 char *pattern = expand_string_to_string(*argv);
3212 /* TODO: which FNM_xxx flags to use? */
3213 cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
3215 if (cond_code == 0) { /* match! we will execute this branch */
3216 free(case_word); /* make future "word)" stop */
3224 if (rword == RES_CASEI) { /* inside of a case branch */
3226 continue; /* not matched yet, skip this pipe */
3229 /* Just pressing <enter> in shell should check for jobs.
3230 * OTOH, in non-interactive shell this is useless
3231 * and only leads to extra job checks */
3232 if (pi->num_cmds == 0) {
3233 if (G_interactive_fd)
3234 goto check_jobs_and_continue;
3238 /* After analyzing all keywords and conditions, we decided
3239 * to execute this pipe. NB: have to do checkjobs(NULL)
3240 * after run_pipe() to collect any background children,
3241 * even if list execution is to be stopped. */
3242 debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
3245 #if ENABLE_HUSH_LOOPS
3246 G.flag_break_continue = 0;
3248 rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
3250 /* we only ran a builtin: rcode is already known
3251 * and we don't need to wait for anything. */
3252 check_and_run_traps(0);
3253 #if ENABLE_HUSH_LOOPS
3254 /* was it "break" or "continue"? */
3255 if (G.flag_break_continue) {
3256 smallint fbc = G.flag_break_continue;
3257 /* we might fall into outer *loop*,
3258 * don't want to break it too */
3260 G.depth_break_continue--;
3261 if (G.depth_break_continue == 0)
3262 G.flag_break_continue = 0;
3263 /* else: e.g. "continue 2" should *break* once, *then* continue */
3264 } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
3265 if (G.depth_break_continue != 0 || fbc == BC_BREAK)
3266 goto check_jobs_and_break;
3267 /* "continue": simulate end of loop */
3272 } else if (pi->followup == PIPE_BG) {
3273 /* what does bash do with attempts to background builtins? */
3274 /* even bash 3.2 doesn't do that well with nested bg:
3275 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
3276 * I'm NOT treating inner &'s as jobs */
3277 check_and_run_traps(0);
3279 if (G.run_list_level == 1)
3282 rcode = 0; /* EXIT_SUCCESS */
3285 if (G.run_list_level == 1 && G_interactive_fd) {
3286 /* waits for completion, then fg's main shell */
3287 rcode = checkjobs_and_fg_shell(pi);
3288 check_and_run_traps(0);
3289 debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
3292 { /* this one just waits for completion */
3293 rcode = checkjobs(pi);
3294 check_and_run_traps(0);
3295 debug_printf_exec(": checkjobs returned %d\n", rcode);
3299 debug_printf_exec(": setting last_return_code=%d\n", rcode);
3300 G.last_return_code = rcode;
3302 /* Analyze how result affects subsequent commands */
3304 if (rword == RES_IF || rword == RES_ELIF)
3307 #if ENABLE_HUSH_LOOPS
3308 if (rword == RES_WHILE) {
3310 rcode = 0; /* "while false; do...done" - exitcode 0 */
3311 goto check_jobs_and_break;
3314 if (rword == RES_UNTIL) {
3316 check_jobs_and_break:
3322 if ((rcode == 0 && pi->followup == PIPE_OR)
3323 || (rcode != 0 && pi->followup == PIPE_AND)
3325 skip_more_for_this_rword = rword;
3328 check_jobs_and_continue:
3333 //// if (G.ctrl_z_flag) {
3334 //// /* ctrl-Z forked somewhere in the past, we are the child,
3335 //// * and now we completed running the list. Exit. */
3341 //// if (!G.run_list_level && G_interactive_fd) {
3342 //// signal(SIGTSTP, SIG_IGN);
3343 //// signal(SIGINT, SIG_IGN);
3346 debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
3347 #if ENABLE_HUSH_LOOPS
3352 #if ENABLE_HUSH_CASE
3358 /* Select which version we will use */
3359 static int run_and_free_list(struct pipe *pi)
3362 debug_printf_exec("run_and_free_list entered\n");
3364 debug_printf_exec(": run_list with %d members\n", pi->num_cmds);
3365 rcode = run_list(pi);
3367 /* free_pipe_list has the side effect of clearing memory.
3368 * In the long run that function can be merged with run_list,
3369 * but doing that now would hobble the debugging effort. */
3370 free_pipe_list(pi, /* indent: */ 0);
3371 debug_printf_exec("run_and_free_list return %d\n", rcode);
3376 /* Peek ahead in the in_str to find out if we have a "&n" construct,
3377 * as in "2>&1", that represents duplicating a file descriptor.
3378 * Return either -2 (syntax error), -1 (no &), or the number found.
3380 static int redirect_dup_num(struct in_str *input)
3382 int ch, d = 0, ok = 0;
3384 if (ch != '&') return -1;
3386 i_getch(input); /* get the & */
3390 return -3; /* "-" represents "close me" */
3392 while (isdigit(ch)) {
3393 d = d*10 + (ch-'0');
3400 bb_error_msg("ambiguous redirect");
3404 /* The src parameter allows us to peek forward to a possible &n syntax
3405 * for file descriptor duplication, e.g., "2>&1".
3406 * Return code is 0 normally, 1 if a syntax error is detected in src.
3407 * Resource errors (in xmalloc) cause the process to exit */
3408 static int setup_redirect(struct parse_context *ctx,
3411 struct in_str *input)
3413 struct command *command = ctx->command;
3414 struct redir_struct *redir;
3415 struct redir_struct **redirp;
3418 /* Check for a '2>&1' type redirect */
3419 dup_num = redirect_dup_num(input);
3421 return 1; /* syntax error */
3423 /* Create a new redir_struct and drop it onto the end of the linked list */
3424 redirp = &command->redirects;
3425 while ((redir = *redirp) != NULL) {
3426 redirp = &(redir->next);
3428 *redirp = redir = xzalloc(sizeof(*redir));
3429 /* redir->next = NULL; */
3430 /* redir->rd_filename = NULL; */
3431 redir->rd_type = style;
3432 redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
3434 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
3436 redir->dup = dup_num;
3437 if (dup_num != -1) {
3438 /* Erik had a check here that the file descriptor in question
3439 * is legit; I postpone that to "run time"
3440 * A "-" representation of "close me" shows up as a -3 here */
3441 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
3443 /* We do _not_ try to open the file that src points to,
3444 * since we need to return and let src be expanded first.
3445 * Set ctx->pending_redirect, so we know what to do at the
3446 * end of the next parsed word. */
3447 ctx->pending_redirect = redir;
3453 static struct pipe *new_pipe(void)
3456 pi = xzalloc(sizeof(struct pipe));
3457 /*pi->followup = 0; - deliberately invalid value */
3458 /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
3462 /* Command (member of a pipe) is complete. The only possible error here
3463 * is out of memory, in which case xmalloc exits. */
3464 static int done_command(struct parse_context *ctx)
3466 /* The command is really already in the pipe structure, so
3467 * advance the pipe counter and make a new, null command. */
3468 struct pipe *pi = ctx->pipe;
3469 struct command *command = ctx->command;
3472 if (command->group == NULL
3473 && command->argv == NULL
3474 && command->redirects == NULL
3476 debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
3477 return pi->num_cmds;
3480 debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
3482 debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
3485 /* Only real trickiness here is that the uncommitted
3486 * command structure is not counted in pi->num_cmds. */
3487 pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
3488 command = &pi->cmds[pi->num_cmds];
3489 memset(command, 0, sizeof(*command));
3491 ctx->command = command;
3492 /* but ctx->pipe and ctx->list_head remain unchanged */
3494 return pi->num_cmds; /* used only for 0/nonzero check */
3497 static void done_pipe(struct parse_context *ctx, pipe_style type)
3501 debug_printf_parse("done_pipe entered, followup %d\n", type);
3502 /* Close previous command */
3503 not_null = done_command(ctx);
3504 ctx->pipe->followup = type;
3505 IF_HAS_KEYWORDS(ctx->pipe->pi_inverted = ctx->ctx_inverted;)
3506 IF_HAS_KEYWORDS(ctx->ctx_inverted = 0;)
3507 IF_HAS_KEYWORDS(ctx->pipe->res_word = ctx->ctx_res_w;)
3509 /* Without this check, even just <enter> on command line generates
3510 * tree of three NOPs (!). Which is harmless but annoying.
3511 * IOW: it is safe to do it unconditionally.
3512 * RES_NONE case is for "for a in; do ..." (empty IN set)
3513 * to work, possibly other cases too. */
3514 if (not_null IF_HAS_KEYWORDS(|| ctx->ctx_res_w != RES_NONE)) {
3516 debug_printf_parse("done_pipe: adding new pipe: "
3517 "not_null:%d ctx->ctx_res_w:%d\n",
3518 not_null, ctx->ctx_res_w);
3520 ctx->pipe->next = new_p;
3522 /* RES_THEN, RES_DO etc are "sticky" -
3523 * they remain set for commands inside if/while.
3524 * This is used to control execution.
3525 * RES_FOR and RES_IN are NOT sticky (needed to support
3526 * cases where variable or value happens to match a keyword):
3528 #if ENABLE_HUSH_LOOPS
3529 if (ctx->ctx_res_w == RES_FOR
3530 || ctx->ctx_res_w == RES_IN)
3531 ctx->ctx_res_w = RES_NONE;
3533 #if ENABLE_HUSH_CASE
3534 if (ctx->ctx_res_w == RES_MATCH)
3535 ctx->ctx_res_w = RES_CASEI;
3537 ctx->command = NULL; /* trick done_command below */
3538 /* Create the memory for command, roughly:
3539 * ctx->pipe->cmds = new struct command;
3540 * ctx->command = &ctx->pipe->cmds[0];
3544 debug_printf_parse("done_pipe return\n");
3547 static void initialize_context(struct parse_context *ctx)
3549 memset(ctx, 0, sizeof(*ctx));
3550 ctx->pipe = ctx->list_head = new_pipe();
3551 /* Create the memory for command, roughly:
3552 * ctx->pipe->cmds = new struct command;
3553 * ctx->command = &ctx->pipe->cmds[0];
3559 /* If a reserved word is found and processed, parse context is modified
3560 * and 1 is returned.
3563 struct reserved_combo {
3566 unsigned char assignment_flag;
3570 FLAG_END = (1 << RES_NONE ),
3572 FLAG_IF = (1 << RES_IF ),
3573 FLAG_THEN = (1 << RES_THEN ),
3574 FLAG_ELIF = (1 << RES_ELIF ),
3575 FLAG_ELSE = (1 << RES_ELSE ),
3576 FLAG_FI = (1 << RES_FI ),
3578 #if ENABLE_HUSH_LOOPS
3579 FLAG_FOR = (1 << RES_FOR ),
3580 FLAG_WHILE = (1 << RES_WHILE),
3581 FLAG_UNTIL = (1 << RES_UNTIL),
3582 FLAG_DO = (1 << RES_DO ),
3583 FLAG_DONE = (1 << RES_DONE ),
3584 FLAG_IN = (1 << RES_IN ),
3586 #if ENABLE_HUSH_CASE
3587 FLAG_MATCH = (1 << RES_MATCH),
3588 FLAG_ESAC = (1 << RES_ESAC ),
3590 FLAG_START = (1 << RES_XXXX ),
3593 static const struct reserved_combo* match_reserved_word(o_string *word)
3595 /* Mostly a list of accepted follow-up reserved words.
3596 * FLAG_END means we are done with the sequence, and are ready
3597 * to turn the compound list into a command.
3598 * FLAG_START means the word must start a new compound list.
3600 static const struct reserved_combo reserved_list[] = {
3602 { "!", RES_NONE, NOT_ASSIGNMENT , 0 },
3603 { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START },
3604 { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
3605 { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN },
3606 { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI },
3607 { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
3609 #if ENABLE_HUSH_LOOPS
3610 { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
3611 { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3612 { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3613 { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
3614 { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE },
3615 { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
3617 #if ENABLE_HUSH_CASE
3618 { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
3619 { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
3622 const struct reserved_combo *r;
3624 for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
3625 if (strcmp(word->data, r->literal) == 0)
3630 static int reserved_word(o_string *word, struct parse_context *ctx)
3632 #if ENABLE_HUSH_CASE
3633 static const struct reserved_combo reserved_match = {
3634 "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
3637 const struct reserved_combo *r;
3639 r = match_reserved_word(word);
3643 debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
3644 #if ENABLE_HUSH_CASE
3645 if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE)
3646 /* "case word IN ..." - IN part starts first match part */
3647 r = &reserved_match;
3650 if (r->flag == 0) { /* '!' */
3651 if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
3652 syntax("! ! command");
3653 IF_HAS_KEYWORDS(ctx->ctx_res_w = RES_SNTX;)
3655 ctx->ctx_inverted = 1;
3658 if (r->flag & FLAG_START) {
3659 struct parse_context *old;
3660 old = xmalloc(sizeof(*old));
3661 debug_printf_parse("push stack %p\n", old);
3662 *old = *ctx; /* physical copy */
3663 initialize_context(ctx);
3665 } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
3667 ctx->ctx_res_w = RES_SNTX;
3670 ctx->ctx_res_w = r->res;
3671 ctx->old_flag = r->flag;
3672 if (ctx->old_flag & FLAG_END) {
3673 struct parse_context *old;
3674 done_pipe(ctx, PIPE_SEQ);
3675 debug_printf_parse("pop stack %p\n", ctx->stack);
3677 old->command->group = ctx->list_head;
3678 old->command->grp_type = GRP_NORMAL;
3680 o_addstr(&old->as_string, ctx->as_string.data);
3681 o_free_unsafe(&ctx->as_string);
3682 old->command->group_as_string = xstrdup(old->as_string.data);
3683 debug_printf_parse("pop, remembering as:'%s'\n",
3684 old->command->group_as_string);
3686 *ctx = *old; /* physical copy */
3689 word->o_assignment = r->assignment_flag;
3694 /* Word is complete, look at it and update parsing context.
3695 * Normal return is 0. Syntax errors return 1.
3696 * Note: on return, word is reset, but not o_free'd!
3698 static int done_word(o_string *word, struct parse_context *ctx)
3700 struct command *command = ctx->command;
3702 debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
3703 if (word->length == 0 && word->nonnull == 0) {
3704 debug_printf_parse("done_word return 0: true null, ignored\n");
3707 /* If this word wasn't an assignment, next ones definitely
3708 * can't be assignments. Even if they look like ones. */
3709 if (word->o_assignment != DEFINITELY_ASSIGNMENT
3710 && word->o_assignment != WORD_IS_KEYWORD
3712 word->o_assignment = NOT_ASSIGNMENT;
3714 if (word->o_assignment == DEFINITELY_ASSIGNMENT)
3715 command->assignment_cnt++;
3716 word->o_assignment = MAYBE_ASSIGNMENT;
3719 if (ctx->pending_redirect) {
3720 /* We do not glob in e.g. >*.tmp case. bash seems to glob here
3721 * only if run as "bash", not "sh" */
3722 ctx->pending_redirect->rd_filename = xstrdup(word->data);
3723 word->o_assignment = NOT_ASSIGNMENT;
3724 debug_printf("word stored in rd_filename: '%s'\n", word->data);
3726 /* "{ echo foo; } echo bar" - bad */
3727 /* NB: bash allows e.g.:
3728 * if true; then { echo foo; } fi
3729 * while if false; then false; fi do break; done
3731 if (command->group) {
3733 debug_printf_parse("done_word return 1: syntax error, "
3734 "groups and arglists don't mix\n");
3738 #if ENABLE_HUSH_CASE
3739 if (ctx->ctx_dsemicolon
3740 && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
3742 /* already done when ctx_dsemicolon was set to 1: */
3743 /* ctx->ctx_res_w = RES_MATCH; */
3744 ctx->ctx_dsemicolon = 0;
3747 if (!command->argv /* if it's the first word... */
3748 #if ENABLE_HUSH_LOOPS
3749 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
3750 && ctx->ctx_res_w != RES_IN
3753 debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
3754 if (reserved_word(word, ctx)) {
3756 debug_printf_parse("done_word return %d\n",
3757 (ctx->ctx_res_w == RES_SNTX));
3758 return (ctx->ctx_res_w == RES_SNTX);
3762 if (word->nonnull /* word had "xx" or 'xx' at least as part of it. */
3763 /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
3764 && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
3765 /* (otherwise it's known to be not empty and is already safe) */
3767 /* exclude "$@" - it can expand to no word despite "" */
3768 char *p = word->data;
3769 while (p[0] == SPECIAL_VAR_SYMBOL
3770 && (p[1] & 0x7f) == '@'
3771 && p[2] == SPECIAL_VAR_SYMBOL
3775 if (p == word->data || p[0] != '\0') {
3776 /* saw no "$@", or not only "$@" but some
3777 * real text is there too */
3778 /* insert "empty variable" reference, this makes
3779 * e.g. "", $empty"" etc to not disappear */
3780 o_addchr(word, SPECIAL_VAR_SYMBOL);
3781 o_addchr(word, SPECIAL_VAR_SYMBOL);
3784 command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
3785 debug_print_strings("word appended to argv", command->argv);
3789 ctx->pending_redirect = NULL;
3791 #if ENABLE_HUSH_LOOPS
3792 /* Force FOR to have just one word (variable name) */
3793 /* NB: basically, this makes hush see "for v in ..." syntax as if
3794 * as it is "for v; in ...". FOR and IN become two pipe structs
3796 if (ctx->ctx_res_w == RES_FOR) {
3797 //TODO: check that command->argv[0] is a valid variable name!
3798 done_pipe(ctx, PIPE_SEQ);
3801 #if ENABLE_HUSH_CASE
3802 /* Force CASE to have just one word */
3803 if (ctx->ctx_res_w == RES_CASE) {
3804 done_pipe(ctx, PIPE_SEQ);
3807 debug_printf_parse("done_word return 0\n");
3811 /* If a redirect is immediately preceded by a number, that number is
3812 * supposed to tell which file descriptor to redirect. This routine
3813 * looks for such preceding numbers. In an ideal world this routine
3814 * needs to handle all the following classes of redirects...
3815 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
3816 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
3817 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
3818 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
3819 * A -1 output from this program means no valid number was found, so the
3820 * caller should use the appropriate default for this redirection.
3822 static int redirect_opt_num(o_string *o)
3828 for (num = 0; num < o->length; num++) {
3829 if (!isdigit(o->data[num])) {
3833 num = atoi(o->data);
3839 #define parse_stream(pstring, input, end_trigger) \
3840 parse_stream(input, end_trigger)
3842 static struct pipe *parse_stream(char **pstring,
3843 struct in_str *input,
3845 static void parse_and_run_string(const char *s);
3847 #if ENABLE_HUSH_TICK
3848 static FILE *generate_stream_from_string(const char *s)
3851 int pid, channel[2];
3854 pid = BB_MMU ? fork() : vfork();
3856 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
3858 if (pid == 0) { /* child */
3859 /* Process substitution is not considered to be usual
3860 * 'command execution'.
3861 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
3868 if (ENABLE_HUSH_JOB)
3869 die_sleep = 0; /* let nofork's xfuncs die */
3870 close(channel[0]); /* NB: close _first_, then move fd! */
3871 xmove_fd(channel[1], 1);
3872 /* Prevent it from trying to handle ctrl-z etc */
3873 USE_HUSH_JOB(G.run_list_level = 1;)
3875 parse_and_run_string(s);
3876 _exit(G.last_return_code);
3878 /* We re-execute after vfork on NOMMU. This makes this script safe:
3879 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >TESTFILE
3880 * huge=`cat TESTFILE` # was blocking here forever
3883 re_execute_shell(s);
3889 pf = fdopen(channel[0], "r");
3893 /* Return code is exit status of the process that is run. */
3894 static int process_command_subs(o_string *dest, const char *s)
3897 struct in_str pipe_str;
3900 pf = generate_stream_from_string(s);
3903 close_on_exec_on(fileno(pf));
3905 /* Now send results of command back into original context */
3906 setup_file_in_str(&pipe_str, pf);
3908 while ((ch = i_getch(&pipe_str)) != EOF) {
3914 o_addchr(dest, '\n');
3917 o_addQchr(dest, ch);
3920 debug_printf("done reading from pipe, pclose()ing\n");
3921 /* Note: we got EOF, and we just close the read end of the pipe.
3922 * We do not wait for the `cmd` child to terminate. bash and ash do.
3924 * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec
3925 * `false`; echo $? - bash outputs "1"
3928 debug_printf("closed FILE from child. return 0\n");
3933 static int parse_group(o_string *dest, struct parse_context *ctx,
3934 struct in_str *input, int ch)
3936 /* dest contains characters seen prior to ( or {.
3937 * Typically it's empty, but for function defs,
3938 * it contains function name (without '()'). */
3939 struct pipe *pipe_list;
3941 struct command *command = ctx->command;
3943 debug_printf_parse("parse_group entered\n");
3944 #if ENABLE_HUSH_FUNCTIONS
3945 if (ch == 'F') { /* function definition? */
3946 bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
3947 //command->fname = dest->data;
3948 command->grp_type = GRP_FUNCTION;
3949 //TODO: review every o_reset() location... do they handle all o_string fields correctly?
3950 memset(dest, 0, sizeof(*dest));
3953 if (command->argv /* word [word](... */
3954 || dest->length /* word(... */
3955 || dest->nonnull /* ""(... */
3958 debug_printf_parse("parse_group return 1: "
3959 "syntax error, groups and arglists don't mix\n");
3965 command->grp_type = GRP_SUBSHELL;
3969 char *as_string = NULL;
3971 pipe_list = parse_stream(&as_string, input, endch);
3974 o_addstr(&ctx->as_string, as_string);
3976 /* empty ()/{} or parse error? */
3977 if (!pipe_list || pipe_list == ERR_PTR) {
3982 debug_printf_parse("parse_group return 1: "
3983 "parse_stream returned %p\n", pipe_list);
3986 command->group = pipe_list;
3988 as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
3989 command->group_as_string = as_string;
3990 debug_printf_parse("end of group, remembering as:'%s'\n",
3991 command->group_as_string);
3994 debug_printf_parse("parse_group return 0\n");
3996 /* command remains "open", available for possible redirects */
3999 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
4000 /* Subroutines for copying $(...) and `...` things */
4001 static void add_till_backquote(o_string *dest, struct in_str *input);
4003 static void add_till_single_quote(o_string *dest, struct in_str *input)
4006 int ch = i_getch(input);
4014 /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
4015 static void add_till_double_quote(o_string *dest, struct in_str *input)
4018 int ch = i_getch(input);
4021 if (ch == '\\') { /* \x. Copy both chars. */
4023 ch = i_getch(input);
4029 add_till_backquote(dest, input);
4033 //if (ch == '$') ...
4036 /* Process `cmd` - copy contents until "`" is seen. Complicated by
4038 * "Within the backquoted style of command substitution, backslash
4039 * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
4040 * The search for the matching backquote shall be satisfied by the first
4041 * backquote found without a preceding backslash; during this search,
4042 * if a non-escaped backquote is encountered within a shell comment,
4043 * a here-document, an embedded command substitution of the $(command)
4044 * form, or a quoted string, undefined results occur. A single-quoted
4045 * or double-quoted string that begins, but does not end, within the
4046 * "`...`" sequence produces undefined results."
4048 * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
4050 static void add_till_backquote(o_string *dest, struct in_str *input)
4053 int ch = i_getch(input);
4056 if (ch == '\\') { /* \x. Copy both chars unless it is \` */
4057 int ch2 = i_getch(input);
4058 if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
4067 /* Process $(cmd) - copy contents until ")" is seen. Complicated by
4068 * quoting and nested ()s.
4069 * "With the $(command) style of command substitution, all characters
4070 * following the open parenthesis to the matching closing parenthesis
4071 * constitute the command. Any valid shell script can be used for command,
4072 * except a script consisting solely of redirections which produces
4073 * unspecified results."
4075 * echo $(echo '(TEST)' BEST) (TEST) BEST
4076 * echo $(echo 'TEST)' BEST) TEST) BEST
4077 * echo $(echo \(\(TEST\) BEST) ((TEST) BEST
4079 static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
4083 int ch = i_getch(input);
4092 if (i_peek(input) == ')') {
4100 add_till_single_quote(dest, input);
4105 add_till_double_quote(dest, input);
4109 if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */
4110 ch = i_getch(input);
4118 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
4120 /* Return code: 0 for OK, 1 for syntax error */
4122 #define handle_dollar(ctx, dest, input) \
4123 handle_dollar(dest, input)
4125 static int handle_dollar(struct parse_context *ctx,
4127 struct in_str *input)
4130 int ch = i_peek(input); /* first character after the $ */
4131 unsigned char quote_mask = dest->o_escape ? 0x80 : 0;
4133 debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
4135 ch = i_getch(input);
4137 if (ctx) o_addchr(&ctx->as_string, ch);
4140 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4142 debug_printf_parse(": '%c'\n", ch);
4143 o_addchr(dest, ch | quote_mask);
4146 if (!isalnum(ch) && ch != '_')
4148 ch = i_getch(input);
4150 if (ctx) o_addchr(&ctx->as_string, ch);
4153 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4154 } else if (isdigit(ch)) {
4156 ch = i_getch(input);
4158 if (ctx) o_addchr(&ctx->as_string, ch);
4160 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4161 debug_printf_parse(": '%c'\n", ch);
4162 o_addchr(dest, ch | quote_mask);
4163 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4164 } else switch (ch) {
4166 case '!': /* last bg pid */
4167 case '?': /* last exit code */
4168 case '#': /* number of args */
4169 case '*': /* args */
4170 case '@': /* args */
4171 goto make_one_char_var;
4173 bool first_char, all_digits;
4175 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4176 ch = i_getch(input);
4178 if (ctx) o_addchr(&ctx->as_string, ch);
4180 /* XXX maybe someone will try to escape the '}' */
4185 ch = i_getch(input);
4187 if (ctx) o_addchr(&ctx->as_string, ch);
4194 /* ${#var}: length of var contents */
4196 else if (isdigit(ch)) {
4203 && ( (all_digits && !isdigit(ch))
4204 || (!all_digits && !isalnum(ch) && ch != '_')
4207 /* handle parameter expansions
4208 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
4213 case ':': /* null modifier */
4214 if (expansion == 0) {
4215 debug_printf_parse(": null modifier\n");
4220 #if 0 /* not implemented yet :( */
4221 case '#': /* remove prefix */
4222 case '%': /* remove suffix */
4223 if (expansion == 0) {
4224 debug_printf_parse(": remove suffix/prefix\n");
4230 case '-': /* default value */
4231 case '=': /* assign default */
4232 case '+': /* alternative */
4233 case '?': /* error indicate */
4234 debug_printf_parse(": parameter expansion\n");
4239 syntax("unterminated ${name}");
4240 debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
4245 debug_printf_parse(": '%c'\n", ch);
4246 o_addchr(dest, ch | quote_mask);
4250 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4257 ch = i_getch(input);
4259 if (ctx) o_addchr(&ctx->as_string, ch);
4261 #if ENABLE_SH_MATH_SUPPORT
4262 if (i_peek(input) == '(') {
4263 ch = i_getch(input);
4265 if (ctx) o_addchr(&ctx->as_string, ch);
4267 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4268 o_addchr(dest, /*quote_mask |*/ '+');
4272 add_till_closing_paren(dest, input, true);
4275 o_addstr(&ctx->as_string, dest->data + pos);
4276 o_addchr(&ctx->as_string, ')');
4277 o_addchr(&ctx->as_string, ')');
4280 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4284 #if ENABLE_HUSH_TICK
4285 //int pos = dest->length;
4286 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4287 o_addchr(dest, quote_mask | '`');
4291 add_till_closing_paren(dest, input, false);
4294 o_addstr(&ctx->as_string, dest->data + pos);
4295 o_addchr(&ctx->as_string, '`');
4298 //debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
4299 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4304 ch = i_getch(input);
4306 if (ctx) o_addchr(&ctx->as_string, ch);
4309 if (isalnum(ch)) { /* it's $_name or $_123 */
4315 /* $_ Shell or shell script name; or last cmd name */
4316 /* $- Option flags set by set builtin or shell options (-i etc) */
4318 o_addQchr(dest, '$');
4320 debug_printf_parse("handle_dollar return 0\n");
4325 #define parse_stream_dquoted(ctx, dest, input, dquote_end) \
4326 parse_stream_dquoted(dest, input, dquote_end)
4328 static int parse_stream_dquoted(struct parse_context *ctx,
4330 struct in_str *input,
4337 ch = i_getch(input);
4339 if (ctx && ch != EOF)
4340 o_addchr(&ctx->as_string, ch);
4342 if (ch == dquote_end) { /* may be only '"' or EOF */
4344 if (dest->o_assignment == NOT_ASSIGNMENT)
4345 dest->o_escape ^= 1;
4346 debug_printf_parse("parse_stream_dquoted return 0\n");
4350 syntax("unterminated \"");
4351 debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n");
4356 next = i_peek(input);
4358 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4359 ch, ch, dest->o_escape);
4363 debug_printf_parse("parse_stream_dquoted return 1: \\<eof>\n");
4367 * "The backslash retains its special meaning [in "..."]
4368 * only when followed by one of the following characters:
4369 * $, `, ", \, or <newline>. A double quote may be quoted
4370 * within double quotes by preceding it with a backslash.
4371 * If enabled, history expansion will be performed unless
4372 * an ! appearing in double quotes is escaped using
4373 * a backslash. The backslash preceding the ! is not removed."
4375 if (strchr("$`\"\\", next) != NULL) {
4376 o_addqchr(dest, i_getch(input));
4378 o_addqchr(dest, '\\');
4383 if (handle_dollar(ctx, dest, input) != 0) {
4384 debug_printf_parse("parse_stream_dquoted return 1: "
4385 "handle_dollar returned non-0\n");
4390 #if ENABLE_HUSH_TICK
4392 //int pos = dest->length;
4393 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4394 o_addchr(dest, 0x80 | '`');
4395 add_till_backquote(dest, input);
4396 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4397 //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
4401 o_addQchr(dest, ch);
4403 && (dest->o_assignment == MAYBE_ASSIGNMENT
4404 || dest->o_assignment == WORD_IS_KEYWORD)
4405 && is_assignment(dest->data)
4407 dest->o_assignment = DEFINITELY_ASSIGNMENT;
4413 * Scan input until EOF or end_trigger char.
4414 * Return a list of pipes to execute, or NULL on EOF
4415 * or if end_trigger character is met.
4416 * On syntax error, exit is shell is not interactive,
4417 * reset parsing machinery and start parsing anew,
4418 * or return ERR_PTR.
4420 static struct pipe *parse_stream(char **pstring,
4421 struct in_str *input,
4424 struct parse_context ctx;
4425 o_string dest = NULL_O_STRING;
4428 /* Double-quote state is handled in the state variable is_in_dquote.
4429 * A single-quote triggers a bypass of the main loop until its mate is
4430 * found. When recursing, quote state is passed in via dest->o_escape.
4432 debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
4433 end_trigger ? : 'X');
4435 G.ifs = get_local_var_value("IFS");
4440 #if ENABLE_HUSH_INTERACTIVE
4441 input->promptmode = 0; /* PS1 */
4443 /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */
4444 initialize_context(&ctx);
4448 const char *is_special;
4452 redir_type redir_style;
4455 if (parse_stream_dquoted(&ctx, &dest, input, '"')) {
4458 /* We reached closing '"' */
4461 ch = i_getch(input);
4462 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4463 ch, ch, dest.o_escape);
4466 if (done_word(&dest, &ctx)) {
4470 done_pipe(&ctx, PIPE_SEQ);
4472 /* If we got nothing... */
4473 // TODO: test script consisting of just "&"
4474 if (pi->num_cmds == 0
4475 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
4477 free_pipe_list(pi, 0);
4480 debug_printf_parse("parse_stream return %p\n", pi);
4482 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4484 *pstring = ctx.as_string.data;
4486 o_free_unsafe(&ctx.as_string);
4491 o_addchr(&ctx.as_string, ch);
4493 is_ifs = strchr(G.ifs, ch);
4494 is_special = strchr("<>;&|(){}#'" /* special outside of "str" */
4495 "\\$\"" USE_HUSH_TICK("`") /* always special */
4498 if (!is_special && !is_ifs) { /* ordinary char */
4499 o_addQchr(&dest, ch);
4500 if ((dest.o_assignment == MAYBE_ASSIGNMENT
4501 || dest.o_assignment == WORD_IS_KEYWORD)
4503 && is_assignment(dest.data)
4505 dest.o_assignment = DEFINITELY_ASSIGNMENT;
4511 if (done_word(&dest, &ctx)) {
4515 #if ENABLE_HUSH_CASE
4516 /* "case ... in <newline> word) ..." -
4517 * newlines are ignored (but ';' wouldn't be) */
4518 if (ctx.command->argv == NULL
4519 && ctx.ctx_res_w == RES_MATCH
4524 /* Treat newline as a command separator. */
4525 done_pipe(&ctx, PIPE_SEQ);
4526 dest.o_assignment = MAYBE_ASSIGNMENT;
4528 /* note: if (is_ifs) continue;
4529 * will still trigger for us */
4532 if (end_trigger && end_trigger == ch) {
4533 //TODO: disallow "{ cmd }" without semicolon
4534 if (done_word(&dest, &ctx)) {
4537 done_pipe(&ctx, PIPE_SEQ);
4538 dest.o_assignment = MAYBE_ASSIGNMENT;
4539 /* Do we sit outside of any if's, loops or case's? */
4541 IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
4543 debug_printf_parse("parse_stream return %p: "
4544 "end_trigger char found\n",
4548 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4550 *pstring = ctx.as_string.data;
4552 o_free_unsafe(&ctx.as_string);
4554 return ctx.list_head;
4560 if (dest.o_assignment == MAYBE_ASSIGNMENT) {
4561 /* ch is a special char and thus this word
4562 * cannot be an assignment */
4563 dest.o_assignment = NOT_ASSIGNMENT;
4568 next = i_peek(input);
4573 if (dest.length == 0) {
4576 if (ch == EOF || ch == '\n')
4579 /* note: we do not add it to &ctx.as_string */
4582 //TODO: go back one char?
4583 o_addchr(&ctx.as_string, '\n');
4586 o_addQchr(&dest, ch);
4594 o_addchr(&dest, '\\');
4595 ch = i_getch(input);
4596 o_addchr(&dest, ch);
4598 o_addchr(&ctx.as_string, ch);
4603 if (handle_dollar(&ctx, &dest, input) != 0) {
4604 debug_printf_parse("parse_stream parse error: "
4605 "handle_dollar returned non-0\n");
4612 ch = i_getch(input);
4614 syntax("unterminated '");
4618 o_addchr(&ctx.as_string, ch);
4622 if (dest.o_assignment == NOT_ASSIGNMENT)
4623 o_addqchr(&dest, ch);
4625 o_addchr(&dest, ch);
4630 is_in_dquote ^= 1; /* invert */
4631 if (dest.o_assignment == NOT_ASSIGNMENT)
4634 #if ENABLE_HUSH_TICK
4636 //int pos = dest.length;
4637 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4638 o_addchr(&dest, '`');
4639 add_till_backquote(&dest, input);
4640 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4641 //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos);
4646 redir_fd = redirect_opt_num(&dest);
4647 if (done_word(&dest, &ctx)) {
4650 redir_style = REDIRECT_OVERWRITE;
4652 redir_style = REDIRECT_APPEND;
4653 ch = i_getch(input);
4655 o_addchr(&ctx.as_string, ch);
4659 else if (next == '(') {
4660 syntax(">(process) not supported");
4664 setup_redirect(&ctx, redir_fd, redir_style, input);
4667 redir_fd = redirect_opt_num(&dest);
4668 if (done_word(&dest, &ctx)) {
4671 redir_style = REDIRECT_INPUT;
4673 redir_style = REDIRECT_HEREIS;
4674 ch = i_getch(input);
4676 o_addchr(&ctx.as_string, ch);
4678 } else if (next == '>') {
4679 redir_style = REDIRECT_IO;
4680 ch = i_getch(input);
4682 o_addchr(&ctx.as_string, ch);
4686 else if (next == '(') {
4687 syntax("<(process) not supported");
4691 setup_redirect(&ctx, redir_fd, redir_style, input);
4694 #if ENABLE_HUSH_CASE
4697 if (done_word(&dest, &ctx)) {
4700 done_pipe(&ctx, PIPE_SEQ);
4701 #if ENABLE_HUSH_CASE
4702 /* Eat multiple semicolons, detect
4703 * whether it means something special */
4708 ch = i_getch(input);
4710 o_addchr(&ctx.as_string, ch);
4712 if (ctx.ctx_res_w == RES_CASEI) {
4713 ctx.ctx_dsemicolon = 1;
4714 ctx.ctx_res_w = RES_MATCH;
4720 /* We just finished a cmd. New one may start
4721 * with an assignment */
4722 dest.o_assignment = MAYBE_ASSIGNMENT;
4725 if (done_word(&dest, &ctx)) {
4729 ch = i_getch(input);
4731 o_addchr(&ctx.as_string, ch);
4733 done_pipe(&ctx, PIPE_AND);
4735 done_pipe(&ctx, PIPE_BG);
4739 if (done_word(&dest, &ctx)) {
4742 #if ENABLE_HUSH_CASE
4743 if (ctx.ctx_res_w == RES_MATCH)
4744 break; /* we are in case's "word | word)" */
4746 if (next == '|') { /* || */
4747 ch = i_getch(input);
4749 o_addchr(&ctx.as_string, ch);
4751 done_pipe(&ctx, PIPE_OR);
4753 /* we could pick up a file descriptor choice here
4754 * with redirect_opt_num(), but bash doesn't do it.
4755 * "echo foo 2| cat" yields "foo 2". */
4760 #if ENABLE_HUSH_CASE
4761 /* "case... in [(]word)..." - skip '(' */
4762 if (ctx.ctx_res_w == RES_MATCH
4763 && ctx.command->argv == NULL /* not (word|(... */
4764 && dest.length == 0 /* not word(... */
4765 && dest.nonnull == 0 /* not ""(... */
4770 #if ENABLE_HUSH_FUNCTIONS
4771 if (dest.length != 0 /* not just () but word() */
4772 && dest.nonnull == 0 /* not a"b"c() */
4773 && ctx.command->argv == NULL /* it's the first word */
4774 //TODO: "func ( ) {...}" - note spaces - is valid format too in bash
4775 && i_peek(input) == ')'
4776 && !match_reserved_word(&dest)
4778 bb_error_msg("seems like a function definition");
4780 //if !BB_MMU o_addchr(&ctx.as_string...
4782 //TODO: do it properly.
4783 ch = i_getch(input);
4784 } while (ch == ' ' || ch == '\n');
4786 syntax("was expecting {");
4789 ch = 'F'; /* magic value */
4793 if (parse_group(&dest, &ctx, input, ch) != 0) {
4798 #if ENABLE_HUSH_CASE
4799 if (ctx.ctx_res_w == RES_MATCH)
4803 /* proper use of this character is caught by end_trigger:
4804 * if we see {, we call parse_group(..., end_trigger='}')
4805 * and it will match } earlier (not here). */
4806 syntax("unexpected } or )");
4810 bb_error_msg_and_die("BUG: unexpected %c\n", ch);
4816 struct parse_context *pctx;
4817 IF_HAS_KEYWORDS(struct parse_context *p2;)
4819 /* Clean up allocated tree.
4820 * Samples for finding leaks on syntax error recovery path.
4821 * Run them from interactive shell, watch pmap `pidof hush`.
4822 * while if false; then false; fi do break; done
4824 * while if false; then false; fi; do break; fi
4828 /* Update pipe/command counts,
4829 * otherwise freeing may miss some */
4830 done_pipe(pctx, PIPE_SEQ);
4831 debug_printf_clean("freeing list %p from ctx %p\n",
4832 pctx->list_head, pctx);
4833 debug_print_tree(pctx->list_head, 0);
4834 free_pipe_list(pctx->list_head, 0);
4835 debug_printf_clean("freed list %p\n", pctx->list_head);
4837 o_free_unsafe(&pctx->as_string);
4839 IF_HAS_KEYWORDS(p2 = pctx->stack;)
4843 IF_HAS_KEYWORDS(pctx = p2;)
4844 } while (HAS_KEYWORDS && pctx);
4845 /* Free text, clear all dest fields */
4847 /* If we are not in top-level parse, we return,
4848 * our caller will propagate error.
4850 if (end_trigger != ';') {
4857 /* Discard cached input, force prompt */
4859 USE_HUSH_INTERACTIVE(input->promptme = 1;)
4864 /* Executing from string: eval, sh -c '...'
4865 * or from file: /etc/profile, . file, sh <script>, sh (intereactive)
4866 * end_trigger controls how often we stop parsing
4867 * NUL: parse all, execute, return
4868 * ';': parse till ';' or newline, execute, repeat till EOF
4870 static void parse_and_run_stream(struct in_str *inp, int end_trigger)
4873 struct pipe *pipe_list;
4875 pipe_list = parse_stream(NULL, inp, end_trigger);
4876 if (!pipe_list) /* EOF */
4878 debug_print_tree(pipe_list, 0);
4879 debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
4880 run_and_free_list(pipe_list);
4884 static void parse_and_run_string(const char *s)
4886 struct in_str input;
4887 setup_string_in_str(&input, s);
4888 parse_and_run_stream(&input, '\0');
4891 static void parse_and_run_file(FILE *f)
4893 struct in_str input;
4894 setup_file_in_str(&input, f);
4895 parse_and_run_stream(&input, ';');
4899 /* Make sure we have a controlling tty. If we get started under a job
4900 * aware app (like bash for example), make sure we are now in charge so
4901 * we don't fight over who gets the foreground */
4902 static void setup_job_control(void)
4906 shell_pgrp = getpgrp();
4908 /* If we were ran as 'hush &',
4909 * sleep until we are in the foreground. */
4910 while (tcgetpgrp(G_interactive_fd) != shell_pgrp) {
4911 /* Send TTIN to ourself (should stop us) */
4912 kill(- shell_pgrp, SIGTTIN);
4913 shell_pgrp = getpgrp();
4916 /* We _must_ restore tty pgrp on fatal signals */
4917 set_fatal_signals_to_sigexit();
4919 /* Put ourselves in our own process group. */
4920 bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
4921 /* Grab control of the terminal. */
4922 tcsetpgrp(G_interactive_fd, getpid());
4926 static int set_mode(const char cstate, const char mode)
4928 int state = (cstate == '-' ? 1 : 0);
4930 case 'n': G.fake_mode = state; break;
4931 case 'x': /*G.debug_mode = state;*/ break;
4932 default: return EXIT_FAILURE;
4934 return EXIT_SUCCESS;
4937 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
4938 int hush_main(int argc, char **argv)
4940 static const struct variable const_shell_ver = {
4942 .varstr = (char*)hush_version_str,
4943 .max_len = 1, /* 0 can provoke free(name) */
4951 struct variable *cur_var;
4955 G.root_pid = getpid();
4957 /* Deal with HUSH_VERSION */
4958 G.shell_ver = const_shell_ver; /* copying struct here */
4959 G.top_var = &G.shell_ver;
4960 debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
4961 unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
4962 /* Initialize our shell local variables with the values
4963 * currently living in the environment */
4964 cur_var = G.top_var;
4967 char *value = strchr(*e, '=');
4968 if (value) { /* paranoia */
4969 cur_var->next = xzalloc(sizeof(*cur_var));
4970 cur_var = cur_var->next;
4971 cur_var->varstr = *e;
4972 cur_var->max_len = strlen(*e);
4973 cur_var->flg_export = 1;
4977 debug_printf_env("putenv '%s'\n", hush_version_str);
4978 putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
4980 #if ENABLE_FEATURE_EDITING
4981 G.line_input_state = new_line_input_t(FOR_SHELL);
4983 /* XXX what should these be while sourcing /etc/profile? */
4984 G.global_argc = argc;
4985 G.global_argv = argv;
4986 /* Initialize some more globals to non-zero values */
4988 #if ENABLE_HUSH_INTERACTIVE
4989 if (ENABLE_FEATURE_EDITING)
4990 cmdedit_set_initial_prompt();
4994 if (EXIT_SUCCESS) /* otherwise is already done */
4995 G.last_return_code = EXIT_SUCCESS;
4997 if (argv[0] && argv[0][0] == '-') {
4998 debug_printf("sourcing /etc/profile\n");
4999 input = fopen_for_read("/etc/profile");
5000 if (input != NULL) {
5001 close_on_exec_on(fileno(input));
5002 parse_and_run_file(input);
5008 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
5010 opt = getopt(argc, argv, "c:xins"
5019 G.global_argv = argv + optind;
5020 if (!argv[optind]) {
5021 /* -c 'script' (no params): prevent empty $0 */
5022 *--G.global_argv = argv[0];
5024 } /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
5025 G.global_argc = argc - optind;
5026 parse_and_run_string(optarg);
5029 /* Well, we cannot just declare interactiveness,
5030 * we have to have some stuff (ctty, etc) */
5031 /* G_interactive_fd++; */
5034 /* "-s" means "read from stdin", but this is how we always
5035 * operate, so simply do nothing here. */
5039 G.root_pid = xatoi_u(optarg);
5042 G.last_return_code = xatoi_u(optarg);
5046 set_local_var(xstrdup(optarg), 0, opt == 'R');
5051 if (!set_mode('-', opt))
5055 fprintf(stderr, "Usage: sh [FILE]...\n"
5056 " or: sh -c command [args]...\n\n");
5064 /* A shell is interactive if the '-i' flag was given, or if all of
5065 * the following conditions are met:
5067 * no arguments remaining or the -s flag given
5068 * standard input is a terminal
5069 * standard output is a terminal
5070 * Refer to Posix.2, the description of the 'sh' utility. */
5071 if (argv[optind] == NULL && input == stdin
5072 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
5074 G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
5075 debug_printf("saved_tty_pgrp=%d\n", G.saved_tty_pgrp);
5076 if (G.saved_tty_pgrp >= 0) {
5077 /* try to dup to high fd#, >= 255 */
5078 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5079 if (G_interactive_fd < 0) {
5080 /* try to dup to any fd */
5081 G_interactive_fd = dup(STDIN_FILENO);
5082 if (G_interactive_fd < 0)
5084 G_interactive_fd = 0;
5086 // TODO: track & disallow any attempts of user
5087 // to (inadvertently) close/redirect it
5090 init_signal_mask(); /* note: ensures SIGCHLD is not masked */
5091 debug_printf("interactive_fd=%d\n", G_interactive_fd);
5092 if (G_interactive_fd) {
5093 fcntl(G_interactive_fd, F_SETFD, FD_CLOEXEC);
5094 /* Looks like they want an interactive shell */
5095 setup_job_control();
5096 /* -1 is special - makes xfuncs longjmp, not exit
5097 * (we reset die_sleep = 0 whereever we [v]fork) */
5099 if (setjmp(die_jmp)) {
5100 /* xfunc has failed! die die die */
5101 hush_exit(xfunc_error_retval);
5104 #elif ENABLE_HUSH_INTERACTIVE
5105 /* no job control compiled, only prompt/line editing */
5106 if (argv[optind] == NULL && input == stdin
5107 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
5109 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5110 if (G_interactive_fd < 0) {
5111 /* try to dup to any fd */
5112 G_interactive_fd = dup(STDIN_FILENO);
5113 if (G_interactive_fd < 0)
5115 G_interactive_fd = 0;
5117 if (G_interactive_fd) {
5118 fcntl(G_interactive_fd, F_SETFD, FD_CLOEXEC);
5121 init_signal_mask(); /* note: ensures SIGCHLD is not masked */
5125 /* POSIX allows shell to re-enable SIGCHLD
5126 * even if it was SIG_IGN on entry */
5127 // G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
5128 signal(SIGCHLD, SIG_DFL); // SIGCHLD_handler);
5130 #if ENABLE_HUSH_INTERACTIVE && !ENABLE_FEATURE_SH_EXTRA_QUIET
5131 if (G_interactive_fd) {
5132 printf("\n\n%s hush - the humble shell v"HUSH_VER_STR"\n", bb_banner);
5133 printf("Enter 'help' for a list of built-in commands.\n\n");
5137 if (argv[optind] == NULL) {
5138 parse_and_run_file(stdin);
5140 debug_printf("\nrunning script '%s'\n", argv[optind]);
5141 G.global_argv = argv + optind;
5142 G.global_argc = argc - optind;
5143 input = xfopen_for_read(argv[optind]);
5144 fcntl(fileno(input), F_SETFD, FD_CLOEXEC);
5145 parse_and_run_file(input);
5150 #if ENABLE_FEATURE_CLEAN_UP
5152 if (G.cwd != bb_msg_unknown)
5154 cur_var = G.top_var->next;
5156 struct variable *tmp = cur_var;
5157 if (!cur_var->max_len)
5158 free(cur_var->varstr);
5159 cur_var = cur_var->next;
5163 hush_exit(G.last_return_code);
5168 int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5169 int lash_main(int argc, char **argv)
5171 //bb_error_msg("lash is deprecated, please use hush instead");
5172 return hush_main(argc, argv);
5180 static int builtin_trap(char **argv)
5187 G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
5190 /* No args: print all trapped. This isn't 100% correct as we should
5191 * be escaping the cmd so that it can be pasted back in ...
5193 for (i = 0; i < NSIG; ++i)
5195 printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
5196 return EXIT_SUCCESS;
5201 /* if first arg is decimal: reset all specified */
5202 sig = bb_strtou(*++argv, NULL, 10);
5208 sig = get_signum(*argv++);
5209 if (sig < 0 || sig >= NSIG) {
5211 /* mimic bash message exactly */
5212 bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
5217 G.traps[sig] = xstrdup(new_cmd);
5219 debug_printf("trap: setting SIG%s (%i) to '%s'",
5220 get_signame(sig), sig, G.traps[sig]);
5222 /* There is no signal for 0 (EXIT) */
5227 sigaddset(&G.blocked_set, sig);
5229 /* there was a trap handler, we are removing it
5230 * (if sig has non-DFL handling,
5231 * we don't need to do anything) */
5232 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
5234 sigdelset(&G.blocked_set, sig);
5236 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5241 /* first arg is "-": reset all specified to default */
5242 /* first arg is "": ignore all specified */
5243 /* everything else: execute first arg upon signal */
5245 bb_error_msg("trap: invalid arguments");
5246 return EXIT_FAILURE;
5248 if (LONE_DASH(*argv))
5256 static int builtin_true(char **argv UNUSED_PARAM)
5261 static int builtin_test(char **argv)
5268 return test_main(argc, argv - argc);
5271 static int builtin_echo(char **argv)
5278 return echo_main(argc, argv - argc);
5281 static int builtin_eval(char **argv)
5283 int rcode = EXIT_SUCCESS;
5286 char *str = expand_strvec_to_string(argv + 1);
5288 * eval "echo Hi; done" ("done" is syntax error):
5289 * "echo Hi" will not execute too.
5291 parse_and_run_string(str);
5293 rcode = G.last_return_code;
5298 static int builtin_cd(char **argv)
5301 if (argv[1] == NULL) {
5302 /* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
5303 * bash says "bash: cd: HOME not set" and does nothing (exitcode 1)
5305 newdir = getenv("HOME") ? : "/";
5308 if (chdir(newdir)) {
5309 printf("cd: %s: %s\n", newdir, strerror(errno));
5310 return EXIT_FAILURE;
5313 return EXIT_SUCCESS;
5316 static int builtin_exec(char **argv)
5318 if (argv[1] == NULL)
5319 return EXIT_SUCCESS; /* bash does this */
5324 // FIXME: if exec fails, bash does NOT exit! We do...
5325 pseudo_exec_argv(&dummy, argv + 1, 0, NULL);
5330 static int builtin_exit(char **argv)
5332 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
5333 //puts("exit"); /* bash does it */
5334 // TODO: warn if we have background jobs: "There are stopped jobs"
5335 // On second consecutive 'exit', exit anyway.
5336 if (argv[1] == NULL)
5337 hush_exit(G.last_return_code);
5338 /* mimic bash: exit 123abc == exit 255 + error msg */
5339 xfunc_error_retval = 255;
5340 /* bash: exit -2 == exit 254, no error msg */
5341 hush_exit(xatoi(argv[1]) & 0xff);
5344 static int builtin_export(char **argv)
5347 char *name = argv[1];
5351 // ash emits: export VAR='VAL'
5352 // bash: declare -x VAR="VAL"
5353 // (both also escape as needed (quotes, $, etc))
5358 return EXIT_SUCCESS;
5361 value = strchr(name, '=');
5363 /* They are exporting something without a =VALUE */
5364 struct variable *var;
5366 var = get_local_var(name);
5368 var->flg_export = 1;
5369 debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
5370 putenv(var->varstr);
5372 /* bash does not return an error when trying to export
5373 * an undefined variable. Do likewise. */
5374 return EXIT_SUCCESS;
5377 set_local_var(xstrdup(name), 1, 0);
5378 return EXIT_SUCCESS;
5382 /* built-in 'fg' and 'bg' handler */
5383 static int builtin_fg_bg(char **argv)
5388 if (!G_interactive_fd)
5389 return EXIT_FAILURE;
5390 /* If they gave us no args, assume they want the last backgrounded task */
5392 for (pi = G.job_list; pi; pi = pi->next) {
5393 if (pi->jobid == G.last_jobid) {
5397 bb_error_msg("%s: no current job", argv[0]);
5398 return EXIT_FAILURE;
5400 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
5401 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
5402 return EXIT_FAILURE;
5404 for (pi = G.job_list; pi; pi = pi->next) {
5405 if (pi->jobid == jobnum) {
5409 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
5410 return EXIT_FAILURE;
5412 // TODO: bash prints a string representation
5413 // of job being foregrounded (like "sleep 1 | cat")
5414 if (argv[0][0] == 'f') {
5415 /* Put the job into the foreground. */
5416 tcsetpgrp(G_interactive_fd, pi->pgrp);
5419 /* Restart the processes in the job */
5420 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
5421 for (i = 0; i < pi->num_cmds; i++) {
5422 debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
5423 pi->cmds[i].is_stopped = 0;
5425 pi->stopped_cmds = 0;
5427 i = kill(- pi->pgrp, SIGCONT);
5429 if (errno == ESRCH) {
5430 delete_finished_bg_job(pi);
5431 return EXIT_SUCCESS;
5433 bb_perror_msg("kill (SIGCONT)");
5436 if (argv[0][0] == 'f') {
5438 return checkjobs_and_fg_shell(pi);
5440 return EXIT_SUCCESS;
5444 #if ENABLE_HUSH_HELP
5445 static int builtin_help(char **argv UNUSED_PARAM)
5447 const struct built_in_command *x;
5450 "Built-in commands:\n"
5451 "------------------\n");
5452 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
5453 printf("%s\t%s\n", x->cmd, x->descr);
5456 return EXIT_SUCCESS;
5461 static int builtin_jobs(char **argv UNUSED_PARAM)
5464 const char *status_string;
5466 for (job = G.job_list; job; job = job->next) {
5467 if (job->alive_cmds == job->stopped_cmds)
5468 status_string = "Stopped";
5470 status_string = "Running";
5472 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
5474 return EXIT_SUCCESS;
5478 static int builtin_pwd(char **argv UNUSED_PARAM)
5481 return EXIT_SUCCESS;
5484 static int builtin_read(char **argv)
5487 const char *name = argv[1] ? argv[1] : "REPLY";
5489 string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
5490 return set_local_var(string, 0, 0);
5493 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
5494 * built-in 'set' handler
5496 * set [-abCefhmnuvx] [-o option] [argument...]
5497 * set [+abCefhmnuvx] [+o option] [argument...]
5498 * set -- [argument...]
5501 * Implementations shall support the options in both their hyphen and
5502 * plus-sign forms. These options can also be specified as options to sh.
5504 * Write out all variables and their values: set
5505 * Set $1, $2, and $3 and set "$#" to 3: set c a b
5506 * Turn on the -x and -v options: set -xv
5507 * Unset all positional parameters: set --
5508 * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
5509 * Set the positional parameters to the expansion of x, even if x expands
5510 * with a leading '-' or '+': set -- $x
5512 * So far, we only support "set -- [argument...]" and some of the short names.
5514 static int builtin_set(char **argv)
5517 char **pp, **g_argv;
5518 char *arg = *++argv;
5522 for (e = G.top_var; e; e = e->next)
5524 return EXIT_SUCCESS;
5528 if (!strcmp(arg, "--")) {
5533 if (arg[0] == '+' || arg[0] == '-') {
5534 for (n = 1; arg[n]; ++n)
5535 if (set_mode(arg[0], arg[n]))
5541 } while ((arg = *++argv) != NULL);
5542 /* Now argv[0] is 1st argument */
5544 /* Only reset global_argv if we didn't process anything */
5546 return EXIT_SUCCESS;
5549 /* NB: G.global_argv[0] ($0) is never freed/changed */
5550 g_argv = G.global_argv;
5551 if (G.global_args_malloced) {
5557 G.global_args_malloced = 1;
5558 pp = xzalloc(sizeof(pp[0]) * 2);
5559 pp[0] = g_argv[0]; /* retain $0 */
5562 /* This realloc's G.global_argv */
5563 G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
5570 return EXIT_SUCCESS;
5572 /* Nothing known, so abort */
5574 bb_error_msg("set: %s: invalid option", arg);
5575 return EXIT_FAILURE;
5578 static int builtin_shift(char **argv)
5584 if (n >= 0 && n < G.global_argc) {
5585 if (G.global_args_malloced) {
5588 free(G.global_argv[m++]);
5591 memmove(&G.global_argv[1], &G.global_argv[n+1],
5592 G.global_argc * sizeof(G.global_argv[0]));
5593 return EXIT_SUCCESS;
5595 return EXIT_FAILURE;
5598 static int builtin_source(char **argv)
5602 if (argv[1] == NULL)
5603 return EXIT_FAILURE;
5605 /* XXX search through $PATH is missing */
5606 input = fopen_for_read(argv[1]);
5608 bb_error_msg("can't open '%s'", argv[1]);
5609 return EXIT_FAILURE;
5611 close_on_exec_on(fileno(input));
5613 /* Now run the file */
5614 /* XXX argv and argc are broken; need to save old G.global_argv
5615 * (pointer only is OK!) on this stack frame,
5616 * set G.global_argv=argv+1, recurse, and restore. */
5617 parse_and_run_file(input);
5619 return G.last_return_code;
5622 static int builtin_umask(char **argv)
5625 const char *arg = argv[1];
5627 new_umask = bb_strtou(arg, NULL, 8);
5629 return EXIT_FAILURE;
5631 new_umask = umask(0);
5632 printf("%.3o\n", (unsigned) new_umask);
5635 return EXIT_SUCCESS;
5638 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
5639 static int builtin_unset(char **argv)
5646 return EXIT_SUCCESS;
5649 if (argv[1][0] == '-') {
5650 switch (argv[1][1]) {
5652 case 'f': if (ENABLE_HUSH_FUNCTIONS) { var = false; break; }
5654 bb_error_msg("unset: %s: invalid option", argv[1]);
5655 return EXIT_FAILURE;
5663 if (unset_local_var(argv[i]))
5666 #if ENABLE_HUSH_FUNCTIONS
5668 unset_local_func(argv[i]);
5674 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
5675 static int builtin_wait(char **argv)
5677 int ret = EXIT_SUCCESS;
5680 if (*++argv == NULL) {
5681 /* Don't care about wait results */
5682 /* Note 1: must wait until there are no more children */
5683 /* Note 2: must be interruptible */
5685 * $ sleep 3 & sleep 6 & wait
5690 * $ sleep 3 & sleep 6 & wait
5694 * ^C <-- after ~4 sec from keyboard
5697 sigaddset(&G.blocked_set, SIGCHLD);
5698 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5701 if (errno == ECHILD)
5703 /* Wait for SIGCHLD or any other signal of interest */
5704 /* sigtimedwait with infinite timeout: */
5705 sig = sigwaitinfo(&G.blocked_set, NULL);
5707 sig = check_and_run_traps(sig);
5708 if (sig && sig != SIGCHLD) { /* see note 2 */
5714 sigdelset(&G.blocked_set, SIGCHLD);
5715 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5719 /* This is probably buggy wrt interruptible-ness */
5721 pid_t pid = bb_strtou(*argv, NULL, 10);
5723 /* mimic bash message */
5724 bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
5725 return EXIT_FAILURE;
5727 if (waitpid(pid, &status, 0) == pid) {
5728 if (WIFSIGNALED(status))
5729 ret = 128 + WTERMSIG(status);
5730 else if (WIFEXITED(status))
5731 ret = WEXITSTATUS(status);
5735 bb_perror_msg("wait %s", *argv);
5744 #if ENABLE_HUSH_LOOPS
5745 static int builtin_break(char **argv)
5747 if (G.depth_of_loop == 0) {
5748 bb_error_msg("%s: only meaningful in a loop", argv[0]);
5749 return EXIT_SUCCESS; /* bash compat */
5751 G.flag_break_continue++; /* BC_BREAK = 1 */
5752 G.depth_break_continue = 1;
5754 G.depth_break_continue = bb_strtou(argv[1], NULL, 10);
5755 if (errno || !G.depth_break_continue || argv[2]) {
5756 bb_error_msg("%s: bad arguments", argv[0]);
5757 G.flag_break_continue = BC_BREAK;
5758 G.depth_break_continue = UINT_MAX;
5761 if (G.depth_of_loop < G.depth_break_continue)
5762 G.depth_break_continue = G.depth_of_loop;
5763 return EXIT_SUCCESS;
5766 static int builtin_continue(char **argv)
5768 G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
5769 return builtin_break(argv);