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> */
79 #define HUSH_VER_STR "0.92"
81 #if defined SINGLE_APPLET_MAIN
82 /* STANDALONE does not make sense, and won't compile */
83 #undef CONFIG_FEATURE_SH_STANDALONE
84 #undef ENABLE_FEATURE_SH_STANDALONE
85 #undef USE_FEATURE_SH_STANDALONE
86 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
87 #define ENABLE_FEATURE_SH_STANDALONE 0
88 #define USE_FEATURE_SH_STANDALONE(...)
89 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
92 #if !ENABLE_HUSH_INTERACTIVE
93 #undef ENABLE_FEATURE_EDITING
94 #define ENABLE_FEATURE_EDITING 0
95 #undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
96 #define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
99 /* Do we support ANY keywords? */
100 #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
101 #define HAS_KEYWORDS 1
102 #define IF_HAS_KEYWORDS(...) __VA_ARGS__
103 #define IF_HAS_NO_KEYWORDS(...)
105 #define HAS_KEYWORDS 0
106 #define IF_HAS_KEYWORDS(...)
107 #define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__
110 /* Keep unconditionally on for now */
113 #define ENABLE_HUSH_FUNCTIONS 0
116 /* If you comment out one of these below, it will be #defined later
117 * to perform debug printfs to stderr: */
118 #define debug_printf(...) do {} while (0)
119 /* Finer-grained debug switches */
120 #define debug_printf_parse(...) do {} while (0)
121 #define debug_print_tree(a, b) do {} while (0)
122 #define debug_printf_exec(...) do {} while (0)
123 #define debug_printf_env(...) do {} while (0)
124 #define debug_printf_jobs(...) do {} while (0)
125 #define debug_printf_expand(...) do {} while (0)
126 #define debug_printf_glob(...) do {} while (0)
127 #define debug_printf_list(...) do {} while (0)
128 #define debug_printf_subst(...) do {} while (0)
129 #define debug_printf_clean(...) do {} while (0)
132 #define debug_printf(...) fprintf(stderr, __VA_ARGS__)
135 #ifndef debug_printf_parse
136 #define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__)
139 #ifndef debug_printf_exec
140 #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__)
143 #ifndef debug_printf_env
144 #define debug_printf_env(...) fprintf(stderr, __VA_ARGS__)
147 #ifndef debug_printf_jobs
148 #define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__)
154 #ifndef debug_printf_expand
155 #define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__)
156 #define DEBUG_EXPAND 1
158 #define DEBUG_EXPAND 0
161 #ifndef debug_printf_glob
162 #define debug_printf_glob(...) fprintf(stderr, __VA_ARGS__)
168 #ifndef debug_printf_list
169 #define debug_printf_list(...) fprintf(stderr, __VA_ARGS__)
172 #ifndef debug_printf_subst
173 #define debug_printf_subst(...) fprintf(stderr, __VA_ARGS__)
176 #ifndef debug_printf_clean
177 /* broken, of course, but OK for testing */
178 static const char *indenter(int i)
180 static const char blanks[] ALIGN1 =
182 return &blanks[sizeof(blanks) - i - 1];
184 #define debug_printf_clean(...) fprintf(stderr, __VA_ARGS__)
185 #define DEBUG_CLEAN 1
189 static void debug_print_strings(const char *prefix, char **vv)
191 fprintf(stderr, "%s:\n", prefix);
193 fprintf(stderr, " '%s'\n", *vv++);
196 #define debug_print_strings(prefix, vv) ((void)0)
200 * Leak hunting. Use hush_leaktool.sh for post-processing.
202 #ifdef FOR_HUSH_LEAKTOOL
203 static void *xxmalloc(int lineno, size_t size)
205 void *ptr = xmalloc((size + 0xff) & ~0xff);
206 fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
209 static void *xxrealloc(int lineno, void *ptr, size_t size)
211 ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
212 fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
215 static char *xxstrdup(int lineno, const char *str)
217 char *ptr = xstrdup(str);
218 fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
221 static void xxfree(void *ptr)
223 fdprintf(2, "free %p\n", ptr);
226 #define xmalloc(s) xxmalloc(__LINE__, s)
227 #define xrealloc(p, s) xxrealloc(__LINE__, p, s)
228 #define xstrdup(s) xxstrdup(__LINE__, s)
229 #define free(p) xxfree(p)
233 #define ERR_PTR ((void*)(long)1)
235 static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="HUSH_VER_STR;
237 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
239 #define SPECIAL_VAR_SYMBOL 3
241 typedef enum redir_type {
243 REDIRECT_OVERWRITE = 2,
249 /* The descrip member of this structure is only used to make
250 * debugging output pretty */
251 static const struct {
253 signed char default_fd;
257 { O_RDONLY, 0, "<" },
258 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
259 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
260 { O_RDONLY, -1, "<<" },
264 typedef enum pipe_style {
271 typedef enum reserved_style {
280 #if ENABLE_HUSH_LOOPS
287 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
292 /* two pseudo-keywords support contrived "case" syntax: */
293 RES_MATCH , /* "word)" */
294 RES_CASEI , /* "this command is inside CASE" */
301 struct redir_struct {
302 struct redir_struct *next;
303 char *rd_filename; /* filename */
304 int fd; /* file descriptor being redirected */
305 int dup; /* -1, or file descriptor being duplicated */
306 smallint /*enum redir_type*/ rd_type;
310 pid_t pid; /* 0 if exited */
311 int assignment_cnt; /* how many argv[i] are assignments? */
312 smallint is_stopped; /* is the command currently running? */
313 smallint grp_type; /* GRP_xxx */
314 struct pipe *group; /* if non-NULL, this "prog" is {} group,
315 * subshell, or a compound statement */
316 char **argv; /* command name and arguments */
317 struct redir_struct *redirects; /* I/O redirections */
319 /* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
320 * and on execution these are substituted with their values.
321 * Substitution can make _several_ words out of one argv[n]!
322 * Example: argv[0]=='.^C*^C.' here: echo .$*.
323 * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
326 #define GRP_SUBSHELL 1
327 #if ENABLE_HUSH_FUNCTIONS
328 #define GRP_FUNCTION 2
333 int num_cmds; /* total number of commands in job */
334 int alive_cmds; /* number of commands running (not exited) */
335 int stopped_cmds; /* number of commands alive, but stopped */
337 int jobid; /* job number */
338 pid_t pgrp; /* process group ID for the job */
339 char *cmdtext; /* name of job */
341 struct command *cmds; /* array of commands in pipe */
342 smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
343 IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */
344 IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */
347 /* This holds pointers to the various results of parsing */
348 struct parse_context {
349 /* linked list of pipes */
350 struct pipe *list_head;
351 /* last pipe (being constructed right now) */
353 /* last command in pipe (being constructed right now) */
354 struct command *command;
355 /* last redirect in command->redirects list */
356 struct redir_struct *pending_redirect;
359 smallint ctx_inverted; /* "! cmd | cmd" */
361 smallint ctx_dsemicolon; /* ";;" seen */
363 /* bitmask of FLAG_xxx, for figuring out valid reserved words */
365 /* group we are enclosed in:
366 * example 1: "{ { false; ..."
367 * example 2: "if true; then { false; ..."
368 * example 3: "if true; then if false; ..."
369 * when we find closing "}" / "fi" / whatever, we move list_head
370 * into stack->command->group and delete ourself.
372 struct parse_context *stack;
376 /* On program start, environ points to initial environment.
377 * putenv adds new pointers into it, unsetenv removes them.
378 * Neither of these (de)allocates the strings.
379 * setenv allocates new strings in malloc space and does putenv,
380 * and thus setenv is unusable (leaky) for shell's purposes */
381 #define setenv(...) setenv_is_leaky_dont_use()
383 struct variable *next;
384 char *varstr; /* points to "name=" portion */
385 int max_len; /* if > 0, name is part of initial env; else name is malloced */
386 smallint flg_export; /* putenv should be done on this var */
387 smallint flg_read_only;
390 typedef struct o_string {
392 int length; /* position where data is appended */
394 /* Protect newly added chars against globbing
395 * (by prepending \ to *, ?, [, \) */
399 smallint has_empty_slot;
400 smallint o_assignment; /* 0:maybe, 1:yes, 2:no */
403 MAYBE_ASSIGNMENT = 0,
404 DEFINITELY_ASSIGNMENT = 1,
406 WORD_IS_KEYWORD = 3, /* not assigment, but next word may be: "if v=xyz cmd;" */
408 /* Used for initialization: o_string foo = NULL_O_STRING; */
409 #define NULL_O_STRING { NULL }
411 /* I can almost use ordinary FILE*. Is open_memstream() universally
412 * available? Where is it documented? */
413 typedef struct in_str {
415 /* eof_flag=1: last char in ->p is really an EOF */
416 char eof_flag; /* meaningless if ->p == NULL */
418 #if ENABLE_HUSH_INTERACTIVE
420 smallint promptmode; /* 0: PS1, 1: PS2 */
423 int (*get) (struct in_str *);
424 int (*peek) (struct in_str *);
426 #define i_getch(input) ((input)->get(input))
427 #define i_peek(input) ((input)->peek(input))
435 /* "Globals" within this file */
436 /* Sorted roughly by size (smaller offsets == smaller code) */
438 #if ENABLE_HUSH_INTERACTIVE
439 /* 'interactive_fd' is a fd# open to ctty, if we have one
440 * _AND_ if we decided to act interactively */
444 #define G_interactive_fd (G.interactive_fd)
446 #define G_interactive_fd 0
448 #if ENABLE_FEATURE_EDITING
449 line_input_t *line_input_state;
455 pid_t saved_tty_pgrp;
457 struct pipe *job_list;
458 struct pipe *toplevel_list;
459 //// smallint ctrl_z_flag;
461 smallint flag_SIGINT;
462 #if ENABLE_HUSH_LOOPS
463 smallint flag_break_continue;
466 /* These four support $?, $#, and $1 */
467 smalluint last_return_code;
468 /* is global_argv and global_argv[1..n] malloced? (note: not [0]) */
469 smalluint global_args_malloced;
470 /* how many non-NULL argv's we have. NB: $# + 1 */
473 #if ENABLE_HUSH_LOOPS
474 unsigned depth_break_continue;
475 unsigned depth_of_loop;
479 struct variable *top_var; /* = &G.shell_ver (set in main()) */
480 struct variable shell_ver;
481 /* Signal and trap handling */
482 // unsigned count_SIGCHLD;
483 // unsigned handled_SIGCHLD;
484 /* which signals have non-DFL handler (even with no traps set)? */
485 unsigned non_DFL_mask;
486 char **traps; /* char *traps[NSIG] */
487 sigset_t blocked_set;
488 sigset_t inherited_set;
489 char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
490 #if ENABLE_FEATURE_SH_STANDALONE
491 struct nofork_save_area nofork_save;
494 sigjmp_buf toplevel_jb;
497 #define G (*ptr_to_globals)
498 /* Not #defining name to G.name - this quickly gets unwieldy
499 * (too many defines). Also, I actually prefer to see when a variable
500 * is global, thus "G." prefix is a useful hint */
501 #define INIT_G() do { \
502 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
506 /* Function prototypes for builtins */
507 static int builtin_cd(char **argv);
508 static int builtin_echo(char **argv);
509 static int builtin_eval(char **argv);
510 static int builtin_exec(char **argv);
511 static int builtin_exit(char **argv);
512 static int builtin_export(char **argv);
514 static int builtin_fg_bg(char **argv);
515 static int builtin_jobs(char **argv);
518 static int builtin_help(char **argv);
520 static int builtin_pwd(char **argv);
521 static int builtin_read(char **argv);
522 static int builtin_test(char **argv);
523 static int builtin_trap(char **argv);
524 static int builtin_true(char **argv);
525 static int builtin_set(char **argv);
526 static int builtin_shift(char **argv);
527 static int builtin_source(char **argv);
528 static int builtin_umask(char **argv);
529 static int builtin_unset(char **argv);
530 static int builtin_wait(char **argv);
531 #if ENABLE_HUSH_LOOPS
532 static int builtin_break(char **argv);
533 static int builtin_continue(char **argv);
535 //static int builtin_not_written(char **argv);
537 /* Table of built-in functions. They can be forked or not, depending on
538 * context: within pipes, they fork. As simple commands, they do not.
539 * When used in non-forking context, they can change global variables
540 * in the parent shell process. If forked, of course they cannot.
541 * For example, 'unset foo | whatever' will parse and run, but foo will
542 * still be set at the end. */
543 struct built_in_command {
545 int (*function)(char **argv);
548 #define BLTIN(cmd, func, help) { cmd, func, help }
550 #define BLTIN(cmd, func, help) { cmd, func }
554 /* For now, echo and test are unconditionally enabled.
555 * Maybe make it configurable? */
556 static const struct built_in_command bltins[] = {
557 BLTIN("." , builtin_source, "Run commands in a file"),
558 BLTIN(":" , builtin_true, "No-op"),
559 BLTIN("[" , builtin_test, "Test condition"),
561 BLTIN("bg" , builtin_fg_bg, "Resume a job in the background"),
563 #if ENABLE_HUSH_LOOPS
564 BLTIN("break" , builtin_break, "Exit from a loop"),
566 BLTIN("cd" , builtin_cd, "Change directory"),
567 #if ENABLE_HUSH_LOOPS
568 BLTIN("continue", builtin_continue, "Start new loop iteration"),
570 BLTIN("echo" , builtin_echo, "Write to stdout"),
571 BLTIN("eval" , builtin_eval, "Construct and run shell command"),
572 BLTIN("exec" , builtin_exec, "Execute command, don't return to shell"),
573 BLTIN("exit" , builtin_exit, "Exit"),
574 BLTIN("export", builtin_export, "Set environment variable"),
576 BLTIN("fg" , builtin_fg_bg, "Bring job into the foreground"),
577 BLTIN("jobs" , builtin_jobs, "List active jobs"),
579 BLTIN("pwd" , builtin_pwd, "Print current directory"),
580 BLTIN("read" , builtin_read, "Input environment variable"),
581 // BLTIN("return", builtin_not_written, "Return from a function"),
582 BLTIN("set" , builtin_set, "Set/unset shell local variables"),
583 BLTIN("shift" , builtin_shift, "Shift positional parameters"),
584 BLTIN("test" , builtin_test, "Test condition"),
585 BLTIN("trap" , builtin_trap, "Trap signals"),
586 // BLTIN("ulimit", builtin_not_written, "Control resource limits"),
587 BLTIN("umask" , builtin_umask, "Set file creation mask"),
588 BLTIN("unset" , builtin_unset, "Unset environment variable"),
589 BLTIN("wait" , builtin_wait, "Wait for process"),
591 BLTIN("help" , builtin_help, "List shell built-in commands"),
597 static void maybe_die(const char *notice, const char *msg)
599 /* Was using fancy stuff:
600 * (G_interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...)
601 * but it SEGVs. ?! Oh well... explicit temp ptr works around that */
602 void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die;
603 #if ENABLE_HUSH_INTERACTIVE
604 if (G_interactive_fd)
607 fp(msg ? "%s: %s" : notice, notice, msg);
610 #define syntax(msg) maybe_die("syntax error", msg);
612 /* Debug -- trick gcc to expand __LINE__ and convert to string */
613 #define __syntax(msg, line) maybe_die("syntax error hush.c:" # line, msg)
614 #define _syntax(msg, line) __syntax(msg, line)
615 #define syntax(msg) _syntax(msg, __LINE__)
618 static int glob_needed(const char *s)
623 if (*s == '*' || *s == '[' || *s == '?')
630 static int is_assignment(const char *s)
632 if (!s || !(isalpha(*s) || *s == '_'))
635 while (isalnum(*s) || *s == '_')
640 /* Replace each \x with x in place, return ptr past NUL. */
641 static char *unbackslash(char *src)
647 if ((*dst++ = *src++) == '\0')
653 static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
674 v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
675 v[count1 + count2] = NULL;
678 v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
682 static char **add_string_to_strings(char **strings, char *add)
687 return add_strings_to_strings(strings, v, /*dup:*/ 0);
690 static void putenv_all(char **strings)
695 debug_printf_env("putenv '%s'\n", *strings);
700 static char **putenv_all_and_save_old(char **strings)
710 eq = strchr(*strings, '=');
713 v = getenv(*strings);
716 /* v points to VAL in VAR=VAL, go back to VAR */
717 v -= (eq - *strings) + 1;
718 old = add_string_to_strings(old, v);
727 static void free_strings_and_unsetenv(char **strings, int unset)
737 debug_printf_env("unsetenv '%s'\n", *v);
745 static void free_strings(char **strings)
747 free_strings_and_unsetenv(strings, 0);
751 /* Basic theory of signal handling in shell
752 * ========================================
753 * This does not describe what hush does, rather, it is current understanding
754 * what it _should_ do. If it doesn't, it's a bug.
755 * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
757 * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
758 * is finished or backgrounded. It is the same in interactive and
759 * non-interactive shells, and is the same regardless of whether
760 * a user trap handler is installed or a shell special one is in effect.
761 * ^C or ^Z from keyboard seem to execute "at once" because it usually
762 * backgrounds (i.e. stops) or kills all members of currently running
765 * Wait builtin in interruptible by signals for which user trap is set
766 * or by SIGINT in interactive shell.
768 * Trap handlers will execute even within trap handlers. (right?)
770 * User trap handlers are forgotten when subshell ("(cmd)") is entered. [TODO]
772 * If job control is off, backgrounded commands ("cmd &")
773 * have SIGINT, SIGQUIT set to SIG_IGN.
775 * Commands run in command substitution ("`cmd`")
776 * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
778 * Ordinary commands have signals set to SIG_IGN/DFL set as inherited
779 * by the shell from its parent.
781 * Siganls which differ from SIG_DFL action
782 * (note: child (i.e., [v]forked) shell is not an interactive shell):
785 * SIGTERM (interactive): ignore
786 * SIGHUP (interactive):
787 * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
788 * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
789 * (note that ^Z is handled not by trapping SIGTSTP, but by seeing
790 * that all pipe members are stopped) (right?)
791 * SIGINT (interactive): wait for last pipe, ignore the rest
792 * of the command line, show prompt. NB: ^C does not send SIGINT
793 * to interactive shell while shell is waiting for a pipe,
794 * since shell is bg'ed (is not in foreground process group).
795 * (check/expand this)
796 * Example 1: this waits 5 sec, but does not execute ls:
797 * "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
798 * Example 2: this does not wait and does not execute ls:
799 * "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
800 * Example 3: this does not wait 5 sec, but executes ls:
801 * "sleep 5; ls -l" + press ^C
803 * (What happens to signals which are IGN on shell start?)
804 * (What happens with signal mask on shell start?)
806 * Implementation in hush
807 * ======================
808 * We use in-kernel pending signal mask to determine which signals were sent.
809 * We block all signals which we don't want to take action immediately,
810 * i.e. we block all signals which need to have special handling as described
811 * above, and all signals which have traps set.
812 * After each pipe execution, we extract any pending signals via sigtimedwait()
815 * unsigned non_DFL_mask: a mask of such "special" signals
816 * sigset_t blocked_set: current blocked signal set
819 * clear bit in blocked_set unless it is also in non_DFL
820 * "trap 'cmd' SIGxxx":
821 * set bit in blocked_set (even if 'cmd' is '')
822 * after [v]fork, if we plan to be a shell:
823 * nothing for {} child shell (say, "true | { true; true; } | true")
824 * unset all traps if () shell. [TODO]
825 * after [v]fork, if we plan to exec:
826 * POSIX says pending signal mask is cleared in child - no need to clear it.
827 * Restore blocked signal set to one inherited by shell just prior to exec.
829 * Note: as a result, we do not use signal handlers much. The only uses
830 * are to count SIGCHLDs [disabled - bug somewhere, + bloat]
831 * and to restore tty pgrp on signal-induced exit.
833 * TODO: check/fix wait builtin to be interruptible.
836 //static void SIGCHLD_handler(int sig UNUSED_PARAM)
838 // G.count_SIGCHLD++;
841 /* called once at shell init */
842 static void init_signal_mask(void)
845 unsigned mask = (1 << SIGQUIT);
846 if (G_interactive_fd) {
852 | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
857 G.non_DFL_mask = mask;
859 sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
863 sigaddset(&G.blocked_set, sig);
867 sigdelset(&G.blocked_set, SIGCHLD);
868 sigprocmask(SIG_SETMASK, &G.blocked_set, &G.inherited_set);
871 static int check_and_run_traps(int sig)
873 static const struct timespec zero_timespec = { 0, 0 };
874 smalluint save_rcode;
880 sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec);
885 if (G.traps && G.traps[sig]) {
886 if (G.traps[sig][0]) {
887 /* We have user-defined handler */
888 char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL };
889 save_rcode = G.last_return_code;
892 G.last_return_code = save_rcode;
893 } /* else: "" trap, ignoring signal */
896 /* not a trap: special action */
899 // G.count_SIGCHLD++;
908 default: /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
917 /* Restores tty foreground process group, and exits.
918 * May be called as signal handler for fatal signal
919 * (will faithfully resend signal to itself, producing correct exit state)
920 * or called directly with -EXITCODE.
921 * We also call it if xfunc is exiting. */
922 static void sigexit(int sig) NORETURN;
923 static void sigexit(int sig)
925 /* Disable all signals: job control, SIGPIPE, etc. */
926 sigprocmask_allsigs(SIG_BLOCK);
928 /* Careful: we can end up here after [v]fork. Do not restore
929 * tty pgrp then, only top-level shell process does that */
930 if (G_interactive_fd && getpid() == G.root_pid)
931 tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
933 /* Not a signal, just exit */
937 kill_myself_with_sig(sig); /* does not return */
941 static void maybe_set_sighandler(int sig)
943 void (*handler)(int);
944 /* non_DFL_mask'ed signals are, well, masked,
945 * no need to set handler for them.
947 if (!((G.non_DFL_mask >> sig) & 1)) {
948 handler = signal(sig, sigexit);
949 if (handler == SIG_IGN) /* oops... restore back to IGN! */
950 signal(sig, handler);
953 /* Used only to set handler to restore pgrp on exit */
954 static void set_fatal_signals_to_sigexit(void)
957 maybe_set_sighandler(SIGILL );
958 maybe_set_sighandler(SIGFPE );
959 maybe_set_sighandler(SIGBUS );
960 maybe_set_sighandler(SIGSEGV);
961 maybe_set_sighandler(SIGTRAP);
962 } /* else: hush is perfect. what SEGV? */
964 maybe_set_sighandler(SIGABRT);
966 /* bash 3.2 seems to handle these just like 'fatal' ones */
967 maybe_set_sighandler(SIGPIPE);
968 maybe_set_sighandler(SIGALRM);
969 maybe_set_sighandler(SIGHUP );
971 /* if we aren't interactive... but in this case
972 * we never want to restore pgrp on exit, and this fn is not called */
973 /*maybe_set_sighandler(SIGTERM);*/
974 /*maybe_set_sighandler(SIGINT );*/
979 #define set_fatal_signals_to_sigexit(handler) ((void)0)
983 /* Restores tty foreground process group, and exits. */
984 static void hush_exit(int exitcode) NORETURN;
985 static void hush_exit(int exitcode)
987 if (G.traps && G.traps[0] && G.traps[0][0]) {
988 char *argv[] = { NULL, xstrdup(G.traps[0]), NULL };
994 fflush(NULL); /* flush all streams */
995 sigexit(- (exitcode & 0xff));
1002 static const char *set_cwd(void)
1004 /* xrealloc_getcwd_or_warn(arg) calls free(arg),
1005 * we must not try to free(bb_msg_unknown) */
1006 if (G.cwd == bb_msg_unknown)
1008 G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
1010 G.cwd = bb_msg_unknown;
1015 /* Get/check local shell variables */
1016 static struct variable *get_local_var(const char *name)
1018 struct variable *cur;
1024 for (cur = G.top_var; cur; cur = cur->next) {
1025 if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
1031 static const char *get_local_var_value(const char *src)
1033 struct variable *var = get_local_var(src);
1035 return strchr(var->varstr, '=') + 1;
1039 /* str holds "NAME=VAL" and is expected to be malloced.
1040 * We take ownership of it.
1041 * flg_export is used by:
1044 * -1: if NAME is set, leave export status alone
1045 * if NAME is not set, do not export
1047 static int set_local_var(char *str, int flg_export)
1049 struct variable *cur;
1053 value = strchr(str, '=');
1054 if (!value) { /* not expected to ever happen? */
1059 name_len = value - str + 1; /* including '=' */
1060 cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
1062 if (strncmp(cur->varstr, str, name_len) != 0) {
1064 /* Bail out. Note that now cur points
1065 * to last var in linked list */
1071 /* We found an existing var with this name */
1073 if (cur->flg_read_only) {
1074 bb_error_msg("%s: readonly variable", str);
1078 debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
1079 unsetenv(str); /* just in case */
1081 if (strcmp(cur->varstr, str) == 0) {
1086 if (cur->max_len >= strlen(str)) {
1087 /* This one is from startup env, reuse space */
1088 strcpy(cur->varstr, str);
1091 /* max_len == 0 signifies "malloced" var, which we can
1092 * (and has to) free */
1096 goto set_str_and_exp;
1099 /* Not found - create next variable struct */
1100 cur->next = xzalloc(sizeof(*cur));
1106 if (flg_export == 1)
1107 cur->flg_export = 1;
1108 if (cur->flg_export) {
1109 debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
1110 return putenv(cur->varstr);
1115 static int unset_local_var(const char *name)
1117 struct variable *cur;
1118 struct variable *prev = prev; /* for gcc */
1122 return EXIT_SUCCESS;
1123 name_len = strlen(name);
1126 if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
1127 if (cur->flg_read_only) {
1128 bb_error_msg("%s: readonly variable", name);
1129 return EXIT_FAILURE;
1131 /* prev is ok to use here because 1st variable, HUSH_VERSION,
1132 * is ro, and we cannot reach this code on the 1st pass */
1133 prev->next = cur->next;
1134 debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
1135 bb_unsetenv(cur->varstr);
1139 return EXIT_SUCCESS;
1144 return EXIT_SUCCESS;
1147 #if ENABLE_SH_MATH_SUPPORT
1148 #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c)))
1149 #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c)))
1150 static char *endofname(const char *name)
1158 if (!is_in_name(*p))
1164 static void arith_set_local_var(const char *name, const char *val, int flags)
1166 /* arith code doesnt malloc space, so do it for it */
1167 char *var = xasprintf("%s=%s", name, val);
1168 set_local_var(var, flags);
1176 static int static_get(struct in_str *i)
1185 static int static_peek(struct in_str *i)
1190 #if ENABLE_HUSH_INTERACTIVE
1192 static void cmdedit_set_initial_prompt(void)
1194 if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1195 G.PS1 = getenv("PS1");
1202 static const char* setup_prompt_string(int promptmode)
1204 const char *prompt_str;
1205 debug_printf("setup_prompt_string %d ", promptmode);
1206 if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1207 /* Set up the prompt */
1208 if (promptmode == 0) { /* PS1 */
1210 G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#');
1215 prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
1216 debug_printf("result '%s'\n", prompt_str);
1220 static void get_user_input(struct in_str *i)
1223 const char *prompt_str;
1225 prompt_str = setup_prompt_string(i->promptmode);
1226 #if ENABLE_FEATURE_EDITING
1227 /* Enable command line editing only while a command line
1228 * is actually being read */
1231 /* buglet: SIGINT will not make new prompt to appear _at once_,
1232 * only after <Enter>. (^C will work) */
1233 r = read_line_input(prompt_str, G.user_input_buf, BUFSIZ-1, G.line_input_state);
1234 /* catch *SIGINT* etc (^C is handled by read_line_input) */
1235 check_and_run_traps(0);
1236 } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */
1237 i->eof_flag = (r < 0);
1238 if (i->eof_flag) { /* EOF/error detected */
1239 G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
1240 G.user_input_buf[1] = '\0';
1245 fputs(prompt_str, stdout);
1247 G.user_input_buf[0] = r = fgetc(i->file);
1248 /*G.user_input_buf[1] = '\0'; - already is and never changed */
1249 //do we need check_and_run_traps(0)? (maybe only if stdin)
1250 } while (G.flag_SIGINT);
1251 i->eof_flag = (r == EOF);
1253 i->p = G.user_input_buf;
1256 #endif /* INTERACTIVE */
1258 /* This is the magic location that prints prompts
1259 * and gets data back from the user */
1260 static int file_get(struct in_str *i)
1264 /* If there is data waiting, eat it up */
1265 if (i->p && *i->p) {
1266 #if ENABLE_HUSH_INTERACTIVE
1270 if (i->eof_flag && !*i->p)
1273 /* need to double check i->file because we might be doing something
1274 * more complicated by now, like sourcing or substituting. */
1275 #if ENABLE_HUSH_INTERACTIVE
1276 if (G_interactive_fd && i->promptme && i->file == stdin) {
1279 } while (!*i->p); /* need non-empty line */
1280 i->promptmode = 1; /* PS2 */
1285 ch = fgetc(i->file);
1287 debug_printf("file_get: got a '%c' %d\n", ch, ch);
1288 #if ENABLE_HUSH_INTERACTIVE
1295 /* All the callers guarantee this routine will never be
1296 * used right after a newline, so prompting is not needed.
1298 static int file_peek(struct in_str *i)
1301 if (i->p && *i->p) {
1302 if (i->eof_flag && !i->p[1])
1306 ch = fgetc(i->file);
1307 i->eof_flag = (ch == EOF);
1308 i->peek_buf[0] = ch;
1309 i->peek_buf[1] = '\0';
1311 debug_printf("file_peek: got a '%c' %d\n", *i->p, *i->p);
1315 static void setup_file_in_str(struct in_str *i, FILE *f)
1317 i->peek = file_peek;
1319 #if ENABLE_HUSH_INTERACTIVE
1321 i->promptmode = 0; /* PS1 */
1327 static void setup_string_in_str(struct in_str *i, const char *s)
1329 i->peek = static_peek;
1330 i->get = static_get;
1331 #if ENABLE_HUSH_INTERACTIVE
1333 i->promptmode = 0; /* PS1 */
1343 #define B_CHUNK (32 * sizeof(char*))
1345 static void o_reset(o_string *o)
1353 static void o_free(o_string *o)
1356 memset(o, 0, sizeof(*o));
1359 static void o_grow_by(o_string *o, int len)
1361 if (o->length + len > o->maxlen) {
1362 o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
1363 o->data = xrealloc(o->data, 1 + o->maxlen);
1367 static void o_addchr(o_string *o, int ch)
1369 debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
1371 o->data[o->length] = ch;
1373 o->data[o->length] = '\0';
1376 static void o_addstr(o_string *o, const char *str, int len)
1379 memcpy(&o->data[o->length], str, len);
1381 o->data[o->length] = '\0';
1384 static void o_addstrauto(o_string *o, const char *str)
1386 o_addstr(o, str, strlen(str) + 1);
1389 static void o_addstr_duplicate_backslash(o_string *o, const char *str, int len)
1394 && (*str != '*' && *str != '?' && *str != '[')
1402 /* My analysis of quoting semantics tells me that state information
1403 * is associated with a destination, not a source.
1405 static void o_addqchr(o_string *o, int ch)
1408 char *found = strchr("*?[\\", ch);
1413 o->data[o->length] = '\\';
1416 o->data[o->length] = ch;
1418 o->data[o->length] = '\0';
1421 static void o_addQchr(o_string *o, int ch)
1424 if (o->o_escape && strchr("*?[\\", ch)) {
1426 o->data[o->length] = '\\';
1430 o->data[o->length] = ch;
1432 o->data[o->length] = '\0';
1435 static void o_addQstr(o_string *o, const char *str, int len)
1438 o_addstr(o, str, len);
1444 int ordinary_cnt = strcspn(str, "*?[\\");
1445 if (ordinary_cnt > len) /* paranoia */
1447 o_addstr(o, str, ordinary_cnt);
1448 if (ordinary_cnt == len)
1450 str += ordinary_cnt;
1451 len -= ordinary_cnt + 1; /* we are processing + 1 char below */
1455 if (ch) { /* it is necessarily one of "*?[\\" */
1457 o->data[o->length] = '\\';
1461 o->data[o->length] = ch;
1463 o->data[o->length] = '\0';
1467 /* A special kind of o_string for $VAR and `cmd` expansion.
1468 * It contains char* list[] at the beginning, which is grown in 16 element
1469 * increments. Actual string data starts at the next multiple of 16 * (char*).
1470 * list[i] contains an INDEX (int!) into this string data.
1471 * It means that if list[] needs to grow, data needs to be moved higher up
1472 * but list[i]'s need not be modified.
1473 * NB: remembering how many list[i]'s you have there is crucial.
1474 * o_finalize_list() operation post-processes this structure - calculates
1475 * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
1477 #if DEBUG_EXPAND || DEBUG_GLOB
1478 static void debug_print_list(const char *prefix, o_string *o, int n)
1480 char **list = (char**)o->data;
1481 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1483 fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n",
1484 prefix, list, n, string_start, o->length, o->maxlen);
1486 fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i],
1487 o->data + (int)list[i] + string_start,
1488 o->data + (int)list[i] + string_start);
1492 const char *p = o->data + (int)list[n - 1] + string_start;
1493 fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
1497 #define debug_print_list(prefix, o, n) ((void)0)
1500 /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
1501 * in list[n] so that it points past last stored byte so far.
1502 * It returns n+1. */
1503 static int o_save_ptr_helper(o_string *o, int n)
1505 char **list = (char**)o->data;
1509 if (!o->has_empty_slot) {
1510 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1511 string_len = o->length - string_start;
1512 if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
1513 debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
1514 /* list[n] points to string_start, make space for 16 more pointers */
1515 o->maxlen += 0x10 * sizeof(list[0]);
1516 o->data = xrealloc(o->data, o->maxlen + 1);
1517 list = (char**)o->data;
1518 memmove(list + n + 0x10, list + n, string_len);
1519 o->length += 0x10 * sizeof(list[0]);
1521 debug_printf_list("list[%d]=%d string_start=%d\n", n, string_len, string_start);
1523 /* We have empty slot at list[n], reuse without growth */
1524 string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
1525 string_len = o->length - string_start;
1526 debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n", n, string_len, string_start);
1527 o->has_empty_slot = 0;
1529 list[n] = (char*)(ptrdiff_t)string_len;
1533 /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
1534 static int o_get_last_ptr(o_string *o, int n)
1536 char **list = (char**)o->data;
1537 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1539 return ((int)(ptrdiff_t)list[n-1]) + string_start;
1542 /* o_glob performs globbing on last list[], saving each result
1543 * as a new list[]. */
1544 static int o_glob(o_string *o, int n)
1550 debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
1552 return o_save_ptr_helper(o, n);
1553 pattern = o->data + o_get_last_ptr(o, n);
1554 debug_printf_glob("glob pattern '%s'\n", pattern);
1555 if (!glob_needed(pattern)) {
1557 o->length = unbackslash(pattern) - o->data;
1558 debug_printf_glob("glob pattern '%s' is literal\n", pattern);
1559 return o_save_ptr_helper(o, n);
1562 memset(&globdata, 0, sizeof(globdata));
1563 gr = glob(pattern, 0, NULL, &globdata);
1564 debug_printf_glob("glob('%s'):%d\n", pattern, gr);
1565 if (gr == GLOB_NOSPACE)
1566 bb_error_msg_and_die("out of memory during glob");
1567 if (gr == GLOB_NOMATCH) {
1568 globfree(&globdata);
1571 if (gr != 0) { /* GLOB_ABORTED ? */
1572 //TODO: testcase for bad glob pattern behavior
1573 bb_error_msg("glob(3) error %d on '%s'", gr, pattern);
1575 if (globdata.gl_pathv && globdata.gl_pathv[0]) {
1576 char **argv = globdata.gl_pathv;
1577 o->length = pattern - o->data; /* "forget" pattern */
1579 o_addstrauto(o, *argv);
1580 n = o_save_ptr_helper(o, n);
1586 globfree(&globdata);
1588 debug_print_list("o_glob returning", o, n);
1592 /* If o->o_glob == 1, glob the string so far remembered.
1593 * Otherwise, just finish current list[] and start new */
1594 static int o_save_ptr(o_string *o, int n)
1596 if (o->o_glob) { /* if globbing is requested */
1597 /* If o->has_empty_slot, list[n] was already globbed
1598 * (if it was requested back then when it was filled)
1599 * so don't do that again! */
1600 if (!o->has_empty_slot)
1601 return o_glob(o, n); /* o_save_ptr_helper is inside */
1603 return o_save_ptr_helper(o, n);
1606 /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
1607 static char **o_finalize_list(o_string *o, int n)
1612 n = o_save_ptr(o, n); /* force growth for list[n] if necessary */
1614 debug_print_list("finalized", o, n);
1615 debug_printf_expand("finalized n:%d\n", n);
1616 list = (char**)o->data;
1617 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1621 list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start;
1627 /* Expansion can recurse */
1628 #if ENABLE_HUSH_TICK
1629 static int process_command_subs(o_string *dest, const char *s);
1631 static char *expand_string_to_string(const char *str);
1632 static int parse_stream_dquoted(o_string *dest, struct in_str *input, int dquote_end);
1634 /* expand_strvec_to_strvec() takes a list of strings, expands
1635 * all variable references within and returns a pointer to
1636 * a list of expanded strings, possibly with larger number
1637 * of strings. (Think VAR="a b"; echo $VAR).
1638 * This new list is allocated as a single malloc block.
1639 * NULL-terminated list of char* pointers is at the beginning of it,
1640 * followed by strings themself.
1641 * Caller can deallocate entire list by single free(list). */
1643 /* Store given string, finalizing the word and starting new one whenever
1644 * we encounter IFS char(s). This is used for expanding variable values.
1645 * End-of-string does NOT finalize word: think about 'echo -$VAR-' */
1646 static int expand_on_ifs(o_string *output, int n, const char *str)
1649 int word_len = strcspn(str, G.ifs);
1651 if (output->o_escape || !output->o_glob)
1652 o_addQstr(output, str, word_len);
1653 else /* protect backslashes against globbing up :) */
1654 o_addstr_duplicate_backslash(output, str, word_len);
1657 if (!*str) /* EOL - do not finalize word */
1659 o_addchr(output, '\0');
1660 debug_print_list("expand_on_ifs", output, n);
1661 n = o_save_ptr(output, n);
1662 str += strspn(str, G.ifs); /* skip ifs chars */
1664 debug_print_list("expand_on_ifs[1]", output, n);
1668 /* Expand all variable references in given string, adding words to list[]
1669 * at n, n+1,... positions. Return updated n (so that list[n] is next one
1670 * to be filled). This routine is extremely tricky: has to deal with
1671 * variables/parameters with whitespace, $* and $@, and constructs like
1672 * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
1673 static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
1675 /* or_mask is either 0 (normal case) or 0x80
1676 * (expansion of right-hand side of assignment == 1-element expand.
1677 * It will also do no globbing, and thus we must not backslash-quote!) */
1679 char first_ch, ored_ch;
1686 debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
1687 debug_print_list("expand_vars_to_list", output, n);
1688 n = o_save_ptr(output, n);
1689 debug_print_list("expand_vars_to_list[0]", output, n);
1691 while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
1692 #if ENABLE_HUSH_TICK
1693 o_string subst_result = NULL_O_STRING;
1695 #if ENABLE_SH_MATH_SUPPORT
1696 char arith_buf[sizeof(arith_t)*3 + 2];
1698 o_addstr(output, arg, p - arg);
1699 debug_print_list("expand_vars_to_list[1]", output, n);
1701 p = strchr(p, SPECIAL_VAR_SYMBOL);
1703 first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
1704 /* "$@" is special. Even if quoted, it can still
1705 * expand to nothing (not even an empty string) */
1706 if ((first_ch & 0x7f) != '@')
1707 ored_ch |= first_ch;
1710 switch (first_ch & 0x7f) {
1711 /* Highest bit in first_ch indicates that var is double-quoted */
1713 val = utoa(G.root_pid);
1715 case '!': /* bg pid */
1716 val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)"";
1718 case '?': /* exitcode */
1719 val = utoa(G.last_return_code);
1721 case '#': /* argc */
1722 if (arg[1] != SPECIAL_VAR_SYMBOL)
1723 /* actually, it's a ${#var} */
1725 val = utoa(G.global_argc ? G.global_argc-1 : 0);
1730 if (!G.global_argv[i])
1732 ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
1733 if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
1734 smallint sv = output->o_escape;
1735 /* unquoted var's contents should be globbed, so don't escape */
1736 output->o_escape = 0;
1737 while (G.global_argv[i]) {
1738 n = expand_on_ifs(output, n, G.global_argv[i]);
1739 debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
1740 if (G.global_argv[i++][0] && G.global_argv[i]) {
1741 /* this argv[] is not empty and not last:
1742 * put terminating NUL, start new word */
1743 o_addchr(output, '\0');
1744 debug_print_list("expand_vars_to_list[2]", output, n);
1745 n = o_save_ptr(output, n);
1746 debug_print_list("expand_vars_to_list[3]", output, n);
1749 output->o_escape = sv;
1751 /* If or_mask is nonzero, we handle assignment 'a=....$@.....'
1752 * and in this case should treat it like '$*' - see 'else...' below */
1753 if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */
1755 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1756 if (++i >= G.global_argc)
1758 o_addchr(output, '\0');
1759 debug_print_list("expand_vars_to_list[4]", output, n);
1760 n = o_save_ptr(output, n);
1762 } else { /* quoted $*: add as one word */
1764 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1765 if (!G.global_argv[++i])
1768 o_addchr(output, G.ifs[0]);
1772 case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
1773 /* "Empty variable", used to make "" etc to not disappear */
1777 #if ENABLE_HUSH_TICK
1778 case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
1781 //TODO: can we just stuff it into "output" directly?
1782 debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
1783 process_command_subs(&subst_result, arg);
1784 debug_printf_subst("SUBST RES '%s'\n", subst_result.data);
1785 val = subst_result.data;
1788 #if ENABLE_SH_MATH_SUPPORT
1789 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
1790 arith_eval_hooks_t hooks;
1795 arg++; /* skip '+' */
1796 *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
1797 debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
1799 /* Optional: skip expansion if expr is simple ("a + 3", "i++" etc) */
1802 unsigned char c = *exp_str++;
1809 if (strchr(" \t+-*/%_", c) != NULL)
1811 c |= 0x20; /* tolower */
1812 if (c >= 'a' && c <= 'z')
1816 /* We need to expand. Example: "echo $(($a + 1)) $((1 + $((2)) ))" */
1818 struct in_str input;
1819 o_string dest = NULL_O_STRING;
1821 setup_string_in_str(&input, arg);
1822 parse_stream_dquoted(&dest, &input, EOF);
1823 //bb_error_msg("'%s' -> '%s'", arg, dest.data);
1824 exp_str = expand_string_to_string(dest.data);
1825 //bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
1829 hooks.lookupvar = get_local_var_value;
1830 hooks.setvar = arith_set_local_var;
1831 hooks.endofname = endofname;
1832 res = arith(exp_str ? exp_str : arg, &errcode, &hooks);
1837 case -3: maybe_die("arith", "exponent less than 0"); break;
1838 case -2: maybe_die("arith", "divide by zero"); break;
1839 case -5: maybe_die("arith", "expression recursion loop detected"); break;
1840 default: maybe_die("arith", "syntax error"); break;
1843 debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
1844 sprintf(arith_buf, arith_t_fmt, res);
1849 default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
1851 bool exp_len = false, exp_null = false;
1852 char *var = arg, exp_save, exp_op, *exp_word;
1855 arg[0] = first_ch & 0x7f;
1857 /* prepare for expansions */
1858 if (var[0] == '#') {
1859 /* handle length expansion ${#var} */
1863 /* maybe handle parameter expansion */
1864 exp_off = strcspn(var, ":-=+?");
1868 exp_save = var[exp_off];
1869 exp_null = exp_save == ':';
1870 exp_word = var + exp_off;
1871 if (exp_null) ++exp_word;
1872 exp_op = *exp_word++;
1873 var[exp_off] = '\0';
1877 /* lookup the variable in question */
1878 if (isdigit(var[0])) {
1879 /* handle_dollar() should have vetted var for us */
1881 if (i < G.global_argc)
1882 val = G.global_argv[i];
1883 /* else val remains NULL: $N with too big N */
1885 val = get_local_var_value(var);
1887 /* handle any expansions */
1889 debug_printf_expand("expand: length of '%s' = ", val);
1890 val = utoa(val ? strlen(val) : 0);
1891 debug_printf_expand("%s\n", val);
1892 } else if (exp_off) {
1893 /* we need to do an expansion */
1894 int exp_test = (!val || (exp_null && !val[0]));
1896 exp_test = !exp_test;
1897 debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
1898 exp_null ? "true" : "false", exp_test);
1901 maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
1905 if (exp_op == '=') {
1906 if (isdigit(var[0]) || var[0] == '#') {
1907 maybe_die(var, "special vars cannot assign in this way");
1910 char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
1911 sprintf(new_var, "%s=%s", var, val);
1912 set_local_var(new_var, -1);
1916 var[exp_off] = exp_save;
1921 #if ENABLE_HUSH_TICK
1924 if (!(first_ch & 0x80)) { /* unquoted $VAR */
1925 debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape);
1927 /* unquoted var's contents should be globbed, so don't escape */
1928 smallint sv = output->o_escape;
1929 output->o_escape = 0;
1930 n = expand_on_ifs(output, n, val);
1932 output->o_escape = sv;
1934 } else { /* quoted $VAR, val will be appended below */
1935 debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape);
1938 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
1940 o_addQstr(output, val, strlen(val));
1942 /* Do the check to avoid writing to a const string */
1943 if (*p != SPECIAL_VAR_SYMBOL)
1944 *p = SPECIAL_VAR_SYMBOL;
1946 #if ENABLE_HUSH_TICK
1947 o_free(&subst_result);
1950 } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
1953 debug_print_list("expand_vars_to_list[a]", output, n);
1954 /* this part is literal, and it was already pre-quoted
1955 * if needed (much earlier), do not use o_addQstr here! */
1956 o_addstrauto(output, arg);
1957 debug_print_list("expand_vars_to_list[b]", output, n);
1958 } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
1959 && !(ored_ch & 0x80) /* and all vars were not quoted. */
1962 /* allow to reuse list[n] later without re-growth */
1963 output->has_empty_slot = 1;
1965 o_addchr(output, '\0');
1970 static char **expand_variables(char **argv, int or_mask)
1975 o_string output = NULL_O_STRING;
1977 if (or_mask & 0x100) {
1978 output.o_escape = 1; /* protect against globbing for "$var" */
1979 /* (unquoted $var will temporarily switch it off) */
1986 n = expand_vars_to_list(&output, n, *v, (char)or_mask);
1989 debug_print_list("expand_variables", &output, n);
1991 /* output.data (malloced in one block) gets returned in "list" */
1992 list = o_finalize_list(&output, n);
1993 debug_print_strings("expand_variables[1]", list);
1997 static char **expand_strvec_to_strvec(char **argv)
1999 return expand_variables(argv, 0x100);
2002 /* Used for expansion of right hand of assignments */
2003 /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs
2005 static char *expand_string_to_string(const char *str)
2007 char *argv[2], **list;
2009 argv[0] = (char*)str;
2011 list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */
2013 if (!list[0] || list[1])
2014 bb_error_msg_and_die("BUG in varexp2");
2015 /* actually, just move string 2*sizeof(char*) bytes back */
2016 overlapping_strcpy((char*)list, list[0]);
2017 debug_printf_expand("string_to_string='%s'\n", (char*)list);
2021 /* Used for "eval" builtin */
2022 static char* expand_strvec_to_string(char **argv)
2026 list = expand_variables(argv, 0x80);
2027 /* Convert all NULs to spaces */
2032 if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
2033 bb_error_msg_and_die("BUG in varexp3");
2034 list[n][-1] = ' '; /* TODO: or to G.ifs[0]? */
2038 overlapping_strcpy((char*)list, list[0]);
2039 debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
2043 static char **expand_assignments(char **argv, int count)
2047 /* Expand assignments into one string each */
2048 for (i = 0; i < count; i++) {
2049 p = add_string_to_strings(p, expand_string_to_string(argv[i]));
2055 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
2056 * and stderr if they are redirected. */
2057 static int setup_redirects(struct command *prog, int squirrel[])
2060 struct redir_struct *redir;
2062 for (redir = prog->redirects; redir; redir = redir->next) {
2063 if (redir->dup == -1 && redir->rd_filename == NULL) {
2064 /* something went wrong in the parse. Pretend it didn't happen */
2067 if (redir->dup == -1) {
2069 mode = redir_table[redir->rd_type].mode;
2070 //TODO: check redir for names like '\\'
2071 p = expand_string_to_string(redir->rd_filename);
2072 openfd = open_or_warn(p, mode);
2075 /* this could get lost if stderr has been redirected, but
2076 bash and ash both lose it as well (though zsh doesn't!) */
2080 openfd = redir->dup;
2083 if (openfd != redir->fd) {
2084 if (squirrel && redir->fd < 3) {
2085 squirrel[redir->fd] = dup(redir->fd);
2088 //close(openfd); // close(-3) ??!
2090 dup2(openfd, redir->fd);
2091 if (redir->dup == -1)
2099 static void restore_redirects(int squirrel[])
2102 for (i = 0; i < 3; i++) {
2105 /* We simply die on error */
2112 #if !defined(DEBUG_CLEAN)
2113 #define free_pipe_list(head, indent) free_pipe_list(head)
2114 #define free_pipe(pi, indent) free_pipe(pi)
2116 static void free_pipe_list(struct pipe *head, int indent);
2118 /* return code is the exit status of the pipe */
2119 static void free_pipe(struct pipe *pi, int indent)
2122 struct command *command;
2123 struct redir_struct *r, *rnext;
2126 if (pi->stopped_cmds > 0)
2128 debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
2129 for (i = 0; i < pi->num_cmds; i++) {
2130 command = &pi->cmds[i];
2131 debug_printf_clean("%s command %d:\n", indenter(indent), i);
2132 if (command->argv) {
2133 for (a = 0, p = command->argv; *p; a++, p++) {
2134 debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p);
2136 free_strings(command->argv);
2137 command->argv = NULL;
2139 /* not "else if": on syntax error, we may have both! */
2140 if (command->group) {
2141 debug_printf_clean("%s begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
2142 free_pipe_list(command->group, indent+3);
2143 debug_printf_clean("%s end group\n", indenter(indent));
2144 command->group = NULL;
2146 for (r = command->redirects; r; r = rnext) {
2147 debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->rd_type].descrip);
2149 /* guard against the case >$FOO, where foo is unset or blank */
2150 if (r->rd_filename) {
2151 debug_printf_clean(" %s\n", r->rd_filename);
2152 free(r->rd_filename);
2153 r->rd_filename = NULL;
2156 debug_printf_clean("&%d\n", r->dup);
2161 command->redirects = NULL;
2163 free(pi->cmds); /* children are an array, they get freed all at once */
2171 static void free_pipe_list(struct pipe *head, int indent)
2173 struct pipe *pi, *next;
2175 for (pi = head; pi; pi = next) {
2177 debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word);
2179 free_pipe(pi, indent);
2180 debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup);
2182 /*pi->next = NULL;*/
2189 typedef struct nommu_save_t {
2195 #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
2196 pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
2197 #define pseudo_exec(nommu_save, command, argv_expanded) \
2198 pseudo_exec(command, argv_expanded)
2201 /* Called after [v]fork() in run_pipe(), or from builtin_exec().
2203 * XXX no exit() here. If you don't exec, use _exit instead.
2204 * The at_exit handlers apparently confuse the calling process,
2205 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
2206 static void pseudo_exec_argv(nommu_save_t *nommu_save, char **argv, int assignment_cnt, char **argv_expanded) NORETURN;
2207 static void pseudo_exec_argv(nommu_save_t *nommu_save, char **argv, int assignment_cnt, char **argv_expanded)
2211 const struct built_in_command *x;
2213 /* If a variable is assigned in a forest, and nobody listens,
2214 * was it ever really set?
2216 if (!argv[assignment_cnt])
2217 _exit(EXIT_SUCCESS);
2219 new_env = expand_assignments(argv, assignment_cnt);
2221 putenv_all(new_env);
2222 free(new_env); /* optional */
2224 nommu_save->new_env = new_env;
2225 nommu_save->old_env = putenv_all_and_save_old(new_env);
2227 if (argv_expanded) {
2228 argv = argv_expanded;
2230 argv = expand_strvec_to_strvec(argv + assignment_cnt);
2232 nommu_save->argv = argv;
2237 * Check if the command matches any of the builtins.
2238 * Depending on context, this might be redundant. But it's
2239 * easier to waste a few CPU cycles than it is to figure out
2240 * if this is one of those cases.
2242 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2243 if (strcmp(argv[0], x->cmd) == 0) {
2244 debug_printf_exec("running builtin '%s'\n", argv[0]);
2245 rcode = x->function(argv);
2251 /* Check if the command matches any busybox applets */
2252 #if ENABLE_FEATURE_SH_STANDALONE
2253 if (strchr(argv[0], '/') == NULL) {
2254 int a = find_applet_by_name(argv[0]);
2256 if (APPLET_IS_NOEXEC(a)) {
2257 debug_printf_exec("running applet '%s'\n", argv[0]);
2258 // is it ok that run_applet_no_and_exit() does exit(), not _exit()?
2259 run_applet_no_and_exit(a, argv);
2261 /* re-exec ourselves with the new arguments */
2262 debug_printf_exec("re-execing applet '%s'\n", argv[0]);
2263 execvp(bb_busybox_exec_path, argv);
2264 /* If they called chroot or otherwise made the binary no longer
2265 * executable, fall through */
2270 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2272 debug_printf_exec("execing '%s'\n", argv[0]);
2273 execvp(argv[0], argv);
2274 bb_perror_msg("can't exec '%s'", argv[0]);
2275 _exit(EXIT_FAILURE);
2278 static int run_list(struct pipe *pi);
2280 /* Called after [v]fork() in run_pipe()
2282 static void pseudo_exec(nommu_save_t *nommu_save, struct command *command, char **argv_expanded) NORETURN;
2283 static void pseudo_exec(nommu_save_t *nommu_save, struct command *command, char **argv_expanded)
2286 pseudo_exec_argv(nommu_save, command->argv, command->assignment_cnt, argv_expanded);
2288 if (command->group) {
2290 bb_error_msg_and_die("nested lists are not supported on NOMMU");
2293 debug_printf_exec("pseudo_exec: run_list\n");
2294 rcode = run_list(command->group);
2295 /* OK to leak memory by not calling free_pipe_list,
2296 * since this process is about to exit */
2301 /* Can happen. See what bash does with ">foo" by itself. */
2302 debug_printf("trying to pseudo_exec null command\n");
2303 _exit(EXIT_SUCCESS);
2307 static const char *get_cmdtext(struct pipe *pi)
2313 /* This is subtle. ->cmdtext is created only on first backgrounding.
2314 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
2315 * On subsequent bg argv is trashed, but we won't use it */
2318 argv = pi->cmds[0].argv;
2319 if (!argv || !argv[0]) {
2320 pi->cmdtext = xzalloc(1);
2325 do len += strlen(*argv) + 1; while (*++argv);
2326 pi->cmdtext = p = xmalloc(len);
2327 argv = pi->cmds[0].argv;
2329 len = strlen(*argv);
2330 memcpy(p, *argv, len);
2338 static void insert_bg_job(struct pipe *pi)
2340 struct pipe *thejob;
2343 /* Linear search for the ID of the job to use */
2345 for (thejob = G.job_list; thejob; thejob = thejob->next)
2346 if (thejob->jobid >= pi->jobid)
2347 pi->jobid = thejob->jobid + 1;
2349 /* Add thejob to the list of running jobs */
2351 thejob = G.job_list = xmalloc(sizeof(*thejob));
2353 for (thejob = G.job_list; thejob->next; thejob = thejob->next)
2355 thejob->next = xmalloc(sizeof(*thejob));
2356 thejob = thejob->next;
2359 /* Physically copy the struct job */
2360 memcpy(thejob, pi, sizeof(struct pipe));
2361 thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
2362 /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */
2363 for (i = 0; i < pi->num_cmds; i++) {
2364 // TODO: do we really need to have so many fields which are just dead weight
2365 // at execution stage?
2366 thejob->cmds[i].pid = pi->cmds[i].pid;
2367 /* all other fields are not used and stay zero */
2369 thejob->next = NULL;
2370 thejob->cmdtext = xstrdup(get_cmdtext(pi));
2372 /* We don't wait for background thejobs to return -- append it
2373 to the list of backgrounded thejobs and leave it alone */
2374 if (G_interactive_fd)
2375 printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext);
2376 G.last_bg_pid = thejob->cmds[0].pid;
2377 G.last_jobid = thejob->jobid;
2380 static void remove_bg_job(struct pipe *pi)
2382 struct pipe *prev_pipe;
2384 if (pi == G.job_list) {
2385 G.job_list = pi->next;
2387 prev_pipe = G.job_list;
2388 while (prev_pipe->next != pi)
2389 prev_pipe = prev_pipe->next;
2390 prev_pipe->next = pi->next;
2393 G.last_jobid = G.job_list->jobid;
2398 /* Remove a backgrounded job */
2399 static void delete_finished_bg_job(struct pipe *pi)
2402 pi->stopped_cmds = 0;
2408 /* Check to see if any processes have exited -- if they
2409 * have, figure out why and see if a job has completed */
2410 static int checkjobs(struct pipe* fg_pipe)
2420 debug_printf_jobs("checkjobs %p\n", fg_pipe);
2423 // if (G.handled_SIGCHLD == G.count_SIGCHLD)
2424 // /* avoid doing syscall, nothing there anyway */
2427 attributes = WUNTRACED;
2428 if (fg_pipe == NULL)
2429 attributes |= WNOHANG;
2431 /* Do we do this right?
2432 * bash-3.00# sleep 20 | false
2434 * [3]+ Stopped sleep 20 | false
2435 * bash-3.00# echo $?
2436 * 1 <========== bg pipe is not fully done, but exitcode is already known!
2439 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
2440 //are stopped. Testcase: "cat | cat" in a script (not on command line)
2441 // + killall -STOP cat
2448 // i = G.count_SIGCHLD;
2449 childpid = waitpid(-1, &status, attributes);
2450 if (childpid <= 0) {
2451 if (childpid && errno != ECHILD)
2452 bb_perror_msg("waitpid");
2453 // else /* Until next SIGCHLD, waitpid's are useless */
2454 // G.handled_SIGCHLD = i;
2457 dead = WIFEXITED(status) || WIFSIGNALED(status);
2460 if (WIFSTOPPED(status))
2461 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
2462 childpid, WSTOPSIG(status), WEXITSTATUS(status));
2463 if (WIFSIGNALED(status))
2464 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
2465 childpid, WTERMSIG(status), WEXITSTATUS(status));
2466 if (WIFEXITED(status))
2467 debug_printf_jobs("pid %d exited, exitcode %d\n",
2468 childpid, WEXITSTATUS(status));
2470 /* Were we asked to wait for fg pipe? */
2472 for (i = 0; i < fg_pipe->num_cmds; i++) {
2473 debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
2474 if (fg_pipe->cmds[i].pid != childpid)
2476 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
2478 fg_pipe->cmds[i].pid = 0;
2479 fg_pipe->alive_cmds--;
2480 if (i == fg_pipe->num_cmds - 1) {
2481 /* last process gives overall exitstatus */
2482 rcode = WEXITSTATUS(status);
2483 IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
2486 fg_pipe->cmds[i].is_stopped = 1;
2487 fg_pipe->stopped_cmds++;
2489 debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
2490 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
2491 if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) {
2492 /* All processes in fg pipe have exited/stopped */
2494 if (fg_pipe->alive_cmds)
2495 insert_bg_job(fg_pipe);
2499 /* There are still running processes in the fg pipe */
2500 goto wait_more; /* do waitpid again */
2502 /* it wasnt fg_pipe, look for process in bg pipes */
2506 /* We asked to wait for bg or orphaned children */
2507 /* No need to remember exitcode in this case */
2508 for (pi = G.job_list; pi; pi = pi->next) {
2509 for (i = 0; i < pi->num_cmds; i++) {
2510 if (pi->cmds[i].pid == childpid)
2511 goto found_pi_and_prognum;
2514 /* Happens when shell is used as init process (init=/bin/sh) */
2515 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
2516 continue; /* do waitpid again */
2518 found_pi_and_prognum:
2521 pi->cmds[i].pid = 0;
2523 if (!pi->alive_cmds) {
2524 if (G_interactive_fd)
2525 printf(JOB_STATUS_FORMAT, pi->jobid,
2526 "Done", pi->cmdtext);
2527 delete_finished_bg_job(pi);
2531 pi->cmds[i].is_stopped = 1;
2535 } /* while (waitpid succeeds)... */
2541 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
2544 int rcode = checkjobs(fg_pipe);
2545 /* Job finished, move the shell to the foreground */
2546 p = getpgid(0); /* pgid of our process */
2547 debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
2548 tcsetpgrp(G_interactive_fd, p);
2553 /* run_pipe() starts all the jobs, but doesn't wait for anything
2554 * to finish. See checkjobs().
2556 * return code is normally -1, when the caller has to wait for children
2557 * to finish to determine the exit status of the pipe. If the pipe
2558 * is a simple builtin command, however, the action is done by the
2559 * time run_pipe returns, and the exit code is provided as the
2562 * The input of the pipe is always stdin, the output is always
2563 * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
2564 * because it tries to avoid running the command substitution in
2565 * subshell, when that is in fact necessary. The subshell process
2566 * now has its stdout directed to the input of the appropriate pipe,
2567 * so this routine is noticeably simpler.
2569 * Returns -1 only if started some children. IOW: we have to
2570 * mask out retvals of builtins etc with 0xff!
2572 static int run_pipe(struct pipe *pi)
2576 int pipefds[2]; /* pipefds[0] is for reading */
2577 struct command *command;
2578 char **argv_expanded;
2580 const struct built_in_command *x;
2582 /* it is not always needed, but we aim to smaller code */
2583 int squirrel[] = { -1, -1, -1 };
2585 const int single_and_fg = (pi->num_cmds == 1 && pi->followup != PIPE_BG);
2587 debug_printf_exec("run_pipe start: single_and_fg=%d\n", single_and_fg);
2593 pi->stopped_cmds = 0;
2595 /* Check if this is a simple builtin (not part of a pipe).
2596 * Builtins within pipes have to fork anyway, and are handled in
2597 * pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
2599 command = &(pi->cmds[0]);
2601 #if ENABLE_HUSH_FUNCTIONS
2602 if (single_and_fg && command->group && command->grp_type == GRP_FUNCTION) {
2603 /* We "execute" function definition */
2604 bb_error_msg("here we ought to remember function definition, and go on");
2605 return EXIT_SUCCESS;
2609 if (single_and_fg && command->group && command->grp_type == GRP_NORMAL) {
2610 debug_printf("non-subshell grouping\n");
2611 setup_redirects(command, squirrel);
2612 debug_printf_exec(": run_list\n");
2613 rcode = run_list(command->group) & 0xff;
2614 restore_redirects(squirrel);
2615 debug_printf_exec("run_pipe return %d\n", rcode);
2616 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2620 argv = command->argv;
2621 argv_expanded = NULL;
2623 if (single_and_fg && argv != NULL) {
2624 char **new_env = NULL;
2625 char **old_env = NULL;
2627 i = command->assignment_cnt;
2628 if (i != 0 && argv[i] == NULL) {
2629 /* assignments, but no command: set local environment */
2630 for (i = 0; argv[i] != NULL; i++) {
2631 debug_printf("local environment set: %s\n", argv[i]);
2632 p = expand_string_to_string(argv[i]);
2633 set_local_var(p, 0);
2635 return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */
2638 /* Expand the rest into (possibly) many strings each */
2639 argv_expanded = expand_strvec_to_strvec(argv + i);
2641 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2642 if (strcmp(argv_expanded[0], x->cmd) != 0)
2644 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
2645 debug_printf("exec with redirects only\n");
2646 setup_redirects(command, NULL);
2647 rcode = EXIT_SUCCESS;
2648 goto clean_up_and_ret1;
2650 debug_printf("builtin inline %s\n", argv_expanded[0]);
2651 /* XXX setup_redirects acts on file descriptors, not FILEs.
2652 * This is perfect for work that comes after exec().
2653 * Is it really safe for inline use? Experimentally,
2654 * things seem to work with glibc. */
2655 setup_redirects(command, squirrel);
2656 new_env = expand_assignments(argv, command->assignment_cnt);
2657 old_env = putenv_all_and_save_old(new_env);
2658 debug_printf_exec(": builtin '%s' '%s'...\n", x->cmd, argv_expanded[1]);
2659 rcode = x->function(argv_expanded) & 0xff;
2660 #if ENABLE_FEATURE_SH_STANDALONE
2663 restore_redirects(squirrel);
2664 free_strings_and_unsetenv(new_env, 1);
2665 putenv_all(old_env);
2666 free(old_env); /* not free_strings()! */
2668 free(argv_expanded);
2669 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2670 debug_printf_exec("run_pipe return %d\n", rcode);
2673 #if ENABLE_FEATURE_SH_STANDALONE
2674 i = find_applet_by_name(argv_expanded[0]);
2675 if (i >= 0 && APPLET_IS_NOFORK(i)) {
2676 setup_redirects(command, squirrel);
2677 save_nofork_data(&G.nofork_save);
2678 new_env = expand_assignments(argv, command->assignment_cnt);
2679 old_env = putenv_all_and_save_old(new_env);
2680 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]);
2681 rcode = run_nofork_applet_prime(&G.nofork_save, i, argv_expanded);
2682 goto clean_up_and_ret;
2687 /* NB: argv_expanded may already be created, and that
2688 * might include `cmd` runs! Do not rerun it! We *must*
2689 * use argv_expanded if it's non-NULL */
2691 /* Going to fork a child per each pipe member */
2695 for (i = 0; i < pi->num_cmds; i++) {
2697 volatile nommu_save_t nommu_save;
2698 nommu_save.new_env = NULL;
2699 nommu_save.old_env = NULL;
2700 nommu_save.argv = NULL;
2702 command = &(pi->cmds[i]);
2703 if (command->argv) {
2704 debug_printf_exec(": pipe member '%s' '%s'...\n", command->argv[0], command->argv[1]);
2706 debug_printf_exec(": pipe member with no argv\n");
2708 /* pipes are inserted between pairs of commands */
2711 if ((i + 1) < pi->num_cmds)
2714 command->pid = BB_MMU ? fork() : vfork();
2715 if (!command->pid) { /* child */
2717 die_sleep = 0; /* let nofork's xfuncs die */
2719 /* Every child adds itself to new process group
2720 * with pgid == pid_of_first_child_in_pipe */
2721 if (G.run_list_level == 1 && G_interactive_fd) {
2724 if (pgrp < 0) /* true for 1st process only */
2726 if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
2727 /* We do it in *every* child, not just first,
2729 tcsetpgrp(G_interactive_fd, pgrp);
2733 xmove_fd(nextin, 0);
2734 xmove_fd(pipefds[1], 1); /* write end */
2736 close(pipefds[0]); /* read end */
2737 /* Like bash, explicit redirects override pipes,
2738 * and the pipe fd is available for dup'ing. */
2739 setup_redirects(command, NULL);
2741 /* Restore default handlers just prior to exec */
2742 /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
2744 /* Stores to nommu_save list of env vars putenv'ed
2745 * (NOMMU, on MMU we don't need that) */
2746 /* cast away volatility... */
2747 pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
2748 /* pseudo_exec() does not return */
2752 /* Clean up after vforked child */
2753 free(nommu_save.argv);
2754 free_strings_and_unsetenv(nommu_save.new_env, 1);
2755 putenv_all(nommu_save.old_env);
2757 free(argv_expanded);
2758 argv_expanded = NULL;
2759 if (command->pid < 0) { /* [v]fork failed */
2760 /* Clearly indicate, was it fork or vfork */
2761 bb_perror_msg(BB_MMU ? "fork" : "vfork");
2765 /* Second and next children need to know pid of first one */
2767 pi->pgrp = command->pid;
2773 if ((i + 1) < pi->num_cmds)
2774 close(pipefds[1]); /* write end */
2775 /* Pass read (output) pipe end to next iteration */
2776 nextin = pipefds[0];
2779 if (!pi->alive_cmds) {
2780 debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
2784 debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
2788 #ifndef debug_print_tree
2789 static void debug_print_tree(struct pipe *pi, int lvl)
2791 static const char *const PIPE[] = {
2797 static const char *RES[] = {
2798 [RES_NONE ] = "NONE" ,
2801 [RES_THEN ] = "THEN" ,
2802 [RES_ELIF ] = "ELIF" ,
2803 [RES_ELSE ] = "ELSE" ,
2806 #if ENABLE_HUSH_LOOPS
2807 [RES_FOR ] = "FOR" ,
2808 [RES_WHILE] = "WHILE",
2809 [RES_UNTIL] = "UNTIL",
2811 [RES_DONE ] = "DONE" ,
2813 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
2816 #if ENABLE_HUSH_CASE
2817 [RES_CASE ] = "CASE" ,
2818 [RES_MATCH] = "MATCH",
2819 [RES_CASEI] = "CASEI",
2820 [RES_ESAC ] = "ESAC" ,
2822 [RES_XXXX ] = "XXXX" ,
2823 [RES_SNTX ] = "SNTX" ,
2825 static const char *const GRPTYPE[] = {
2828 #if ENABLE_HUSH_FUNCTIONS
2837 fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
2838 pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
2840 while (prn < pi->num_cmds) {
2841 struct command *command = &pi->cmds[prn];
2842 char **argv = command->argv;
2844 fprintf(stderr, "%*s prog %d assignment_cnt:%d", lvl*2, "", prn, command->assignment_cnt);
2845 if (command->group) {
2846 fprintf(stderr, " group %s: (argv=%p)\n",
2847 GRPTYPE[command->grp_type],
2849 debug_print_tree(command->group, lvl+1);
2853 if (argv) while (*argv) {
2854 fprintf(stderr, " '%s'", *argv);
2857 fprintf(stderr, "\n");
2866 /* NB: called by pseudo_exec, and therefore must not modify any
2867 * global data until exec/_exit (we can be a child after vfork!) */
2868 static int run_list(struct pipe *pi)
2870 #if ENABLE_HUSH_CASE
2871 char *case_word = NULL;
2873 #if ENABLE_HUSH_LOOPS
2874 struct pipe *loop_top = NULL;
2875 char *for_varname = NULL;
2876 char **for_lcur = NULL;
2877 char **for_list = NULL;
2879 smallint flag_skip = 1;
2880 smalluint rcode = 0; /* probably just for compiler */
2881 #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
2882 smalluint cond_code = 0;
2884 enum { cond_code = 0, };
2886 /*enum reserved_style*/ smallint rword = RES_NONE;
2887 /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
2889 debug_printf_exec("run_list start lvl %d\n", G.run_list_level + 1);
2891 #if ENABLE_HUSH_LOOPS
2892 /* Check syntax for "for" */
2893 for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
2894 if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
2896 /* current word is FOR or IN (BOLD in comments below) */
2897 if (cpipe->next == NULL) {
2898 syntax("malformed for");
2899 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
2902 /* "FOR v; do ..." and "for v IN a b; do..." are ok */
2903 if (cpipe->next->res_word == RES_DO)
2905 /* next word is not "do". It must be "in" then ("FOR v in ...") */
2906 if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
2907 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
2909 syntax("malformed for");
2910 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
2916 /* Past this point, all code paths should jump to ret: label
2917 * in order to return, no direct "return" statements please.
2918 * This helps to ensure that no memory is leaked. */
2920 ////TODO: ctrl-Z handling needs re-thinking and re-testing
2923 /* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
2924 * We are saving state before entering outermost list ("while...done")
2925 * so that ctrl-Z will correctly background _entire_ outermost list,
2926 * not just a part of it (like "sleep 1 | exit 2") */
2927 if (++G.run_list_level == 1 && G_interactive_fd) {
2928 if (sigsetjmp(G.toplevel_jb, 1)) {
2929 /* ctrl-Z forked and we are parent; or ctrl-C.
2930 * Sighandler has longjmped us here */
2931 signal(SIGINT, SIG_IGN);
2932 signal(SIGTSTP, SIG_IGN);
2933 /* Restore level (we can be coming from deep inside
2935 G.run_list_level = 1;
2936 #if ENABLE_FEATURE_SH_STANDALONE
2937 if (G.nofork_save.saved) { /* if save area is valid */
2938 debug_printf_jobs("exiting nofork early\n");
2939 restore_nofork_data(&G.nofork_save);
2942 //// if (G.ctrl_z_flag) {
2943 //// /* ctrl-Z has forked and stored pid of the child in pi->pid.
2944 //// * Remember this child as background job */
2945 //// insert_bg_job(pi);
2947 /* ctrl-C. We just stop doing whatever we were doing */
2950 USE_HUSH_LOOPS(loop_top = NULL;)
2951 USE_HUSH_LOOPS(G.depth_of_loop = 0;)
2955 //// /* ctrl-Z handler will store pid etc in pi */
2956 //// G.toplevel_list = pi;
2957 //// G.ctrl_z_flag = 0;
2958 ////#if ENABLE_FEATURE_SH_STANDALONE
2959 //// G.nofork_save.saved = 0; /* in case we will run a nofork later */
2961 //// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
2962 //// signal(SIGINT, handler_ctrl_c);
2966 /* Go through list of pipes, (maybe) executing them. */
2967 for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
2971 IF_HAS_KEYWORDS(rword = pi->res_word;)
2972 IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
2973 debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
2974 rword, cond_code, skip_more_for_this_rword);
2975 #if ENABLE_HUSH_LOOPS
2976 if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
2977 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
2979 /* start of a loop: remember where loop starts */
2984 if (rword == skip_more_for_this_rword && flag_skip) {
2985 if (pi->followup == PIPE_SEQ)
2987 /* it is "<false> && CMD" or "<true> || CMD"
2988 * and we should not execute CMD */
2992 skip_more_for_this_rword = RES_XXXX;
2995 if (rword == RES_THEN) {
2996 /* "if <false> THEN cmd": skip cmd */
3000 if (rword == RES_ELSE || rword == RES_ELIF) {
3001 /* "if <true> then ... ELSE/ELIF cmd":
3002 * skip cmd and all following ones */
3007 #if ENABLE_HUSH_LOOPS
3008 if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
3010 /* first loop through for */
3012 static const char encoded_dollar_at[] ALIGN1 = {
3013 SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
3014 }; /* encoded representation of "$@" */
3015 static const char *const encoded_dollar_at_argv[] = {
3016 encoded_dollar_at, NULL
3017 }; /* argv list with one element: "$@" */
3020 vals = (char**)encoded_dollar_at_argv;
3021 if (pi->next->res_word == RES_IN) {
3022 /* if no variable values after "in" we skip "for" */
3023 if (!pi->next->cmds[0].argv)
3025 vals = pi->next->cmds[0].argv;
3026 } /* else: "for var; do..." -> assume "$@" list */
3027 /* create list of variable values */
3028 debug_print_strings("for_list made from", vals);
3029 for_list = expand_strvec_to_strvec(vals);
3030 for_lcur = for_list;
3031 debug_print_strings("for_list", for_list);
3032 for_varname = pi->cmds[0].argv[0];
3033 pi->cmds[0].argv[0] = NULL;
3035 free(pi->cmds[0].argv[0]);
3037 /* "for" loop is over, clean up */
3041 pi->cmds[0].argv[0] = for_varname;
3044 /* insert next value from for_lcur */
3045 //TODO: does it need escaping?
3046 pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
3047 pi->cmds[0].assignment_cnt = 1;
3049 if (rword == RES_IN) /* "for v IN list;..." - "in" has no cmds anyway */
3051 if (rword == RES_DONE) {
3052 continue; /* "done" has no cmds too */
3055 #if ENABLE_HUSH_CASE
3056 if (rword == RES_CASE) {
3057 case_word = expand_strvec_to_string(pi->cmds->argv);
3060 if (rword == RES_MATCH) {
3063 if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
3065 /* all prev words didn't match, does this one match? */
3066 argv = pi->cmds->argv;
3068 char *pattern = expand_string_to_string(*argv);
3069 /* TODO: which FNM_xxx flags to use? */
3070 cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
3072 if (cond_code == 0) { /* match! we will execute this branch */
3073 free(case_word); /* make future "word)" stop */
3081 if (rword == RES_CASEI) { /* inside of a case branch */
3083 continue; /* not matched yet, skip this pipe */
3086 /* Just pressing <enter> in shell should check for jobs.
3087 * OTOH, in non-interactive shell this is useless
3088 * and only leads to extra job checks */
3089 if (pi->num_cmds == 0) {
3090 if (G_interactive_fd)
3091 goto check_jobs_and_continue;
3095 /* After analyzing all keywords and conditions, we decided
3096 * to execute this pipe. NB: have to do checkjobs(NULL)
3097 * after run_pipe() to collect any background children,
3098 * even if list execution is to be stopped. */
3099 debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
3102 #if ENABLE_HUSH_LOOPS
3103 G.flag_break_continue = 0;
3105 rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
3107 /* we only ran a builtin: rcode is already known
3108 * and we don't need to wait for anything. */
3109 check_and_run_traps(0);
3110 #if ENABLE_HUSH_LOOPS
3111 /* was it "break" or "continue"? */
3112 if (G.flag_break_continue) {
3113 smallint fbc = G.flag_break_continue;
3114 /* we might fall into outer *loop*,
3115 * don't want to break it too */
3117 G.depth_break_continue--;
3118 if (G.depth_break_continue == 0)
3119 G.flag_break_continue = 0;
3120 /* else: e.g. "continue 2" should *break* once, *then* continue */
3121 } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
3122 if (G.depth_break_continue != 0 || fbc == BC_BREAK)
3123 goto check_jobs_and_break;
3124 /* "continue": simulate end of loop */
3129 } else if (pi->followup == PIPE_BG) {
3130 /* what does bash do with attempts to background builtins? */
3131 /* even bash 3.2 doesn't do that well with nested bg:
3132 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
3133 * I'm NOT treating inner &'s as jobs */
3134 check_and_run_traps(0);
3136 if (G.run_list_level == 1)
3139 rcode = 0; /* EXIT_SUCCESS */
3142 if (G.run_list_level == 1 && G_interactive_fd) {
3143 /* waits for completion, then fg's main shell */
3144 rcode = checkjobs_and_fg_shell(pi);
3145 check_and_run_traps(0);
3146 debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
3149 { /* this one just waits for completion */
3150 rcode = checkjobs(pi);
3151 check_and_run_traps(0);
3152 debug_printf_exec(": checkjobs returned %d\n", rcode);
3156 debug_printf_exec(": setting last_return_code=%d\n", rcode);
3157 G.last_return_code = rcode;
3159 /* Analyze how result affects subsequent commands */
3161 if (rword == RES_IF || rword == RES_ELIF)
3164 #if ENABLE_HUSH_LOOPS
3165 if (rword == RES_WHILE) {
3167 rcode = 0; /* "while false; do...done" - exitcode 0 */
3168 goto check_jobs_and_break;
3171 if (rword == RES_UNTIL) {
3173 check_jobs_and_break:
3179 if ((rcode == 0 && pi->followup == PIPE_OR)
3180 || (rcode != 0 && pi->followup == PIPE_AND)
3182 skip_more_for_this_rword = rword;
3185 check_jobs_and_continue:
3190 //// if (G.ctrl_z_flag) {
3191 //// /* ctrl-Z forked somewhere in the past, we are the child,
3192 //// * and now we completed running the list. Exit. */
3198 //// if (!G.run_list_level && G_interactive_fd) {
3199 //// signal(SIGTSTP, SIG_IGN);
3200 //// signal(SIGINT, SIG_IGN);
3203 debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
3204 #if ENABLE_HUSH_LOOPS
3209 #if ENABLE_HUSH_CASE
3215 /* Select which version we will use */
3216 static int run_and_free_list(struct pipe *pi)
3219 debug_printf_exec("run_and_free_list entered\n");
3221 debug_printf_exec(": run_list with %d members\n", pi->num_cmds);
3222 rcode = run_list(pi);
3224 /* free_pipe_list has the side effect of clearing memory.
3225 * In the long run that function can be merged with run_list,
3226 * but doing that now would hobble the debugging effort. */
3227 free_pipe_list(pi, /* indent: */ 0);
3228 debug_printf_exec("run_and_free_list return %d\n", rcode);
3233 /* Peek ahead in the in_str to find out if we have a "&n" construct,
3234 * as in "2>&1", that represents duplicating a file descriptor.
3235 * Return either -2 (syntax error), -1 (no &), or the number found.
3237 static int redirect_dup_num(struct in_str *input)
3239 int ch, d = 0, ok = 0;
3241 if (ch != '&') return -1;
3243 i_getch(input); /* get the & */
3247 return -3; /* "-" represents "close me" */
3249 while (isdigit(ch)) {
3250 d = d*10 + (ch-'0');
3257 bb_error_msg("ambiguous redirect");
3261 /* The src parameter allows us to peek forward to a possible &n syntax
3262 * for file descriptor duplication, e.g., "2>&1".
3263 * Return code is 0 normally, 1 if a syntax error is detected in src.
3264 * Resource errors (in xmalloc) cause the process to exit */
3265 static int setup_redirect(struct parse_context *ctx,
3268 struct in_str *input)
3270 struct command *command = ctx->command;
3271 struct redir_struct *redir;
3272 struct redir_struct **redirp;
3275 /* Check for a '2>&1' type redirect */
3276 dup_num = redirect_dup_num(input);
3278 return 1; /* syntax error */
3280 /* Create a new redir_struct and drop it onto the end of the linked list */
3281 redirp = &command->redirects;
3282 while ((redir = *redirp) != NULL) {
3283 redirp = &(redir->next);
3285 *redirp = redir = xzalloc(sizeof(*redir));
3286 /* redir->next = NULL; */
3287 /* redir->rd_filename = NULL; */
3288 redir->rd_type = style;
3289 redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
3291 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
3293 redir->dup = dup_num;
3294 if (dup_num != -1) {
3295 /* Erik had a check here that the file descriptor in question
3296 * is legit; I postpone that to "run time"
3297 * A "-" representation of "close me" shows up as a -3 here */
3298 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
3300 /* We do _not_ try to open the file that src points to,
3301 * since we need to return and let src be expanded first.
3302 * Set ctx->pending_redirect, so we know what to do at the
3303 * end of the next parsed word. */
3304 ctx->pending_redirect = redir;
3310 static struct pipe *new_pipe(void)
3313 pi = xzalloc(sizeof(struct pipe));
3314 /*pi->followup = 0; - deliberately invalid value */
3315 /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
3319 /* Command (member of a pipe) is complete. The only possible error here
3320 * is out of memory, in which case xmalloc exits. */
3321 static int done_command(struct parse_context *ctx)
3323 /* The command is really already in the pipe structure, so
3324 * advance the pipe counter and make a new, null command. */
3325 struct pipe *pi = ctx->pipe;
3326 struct command *command = ctx->command;
3329 if (command->group == NULL
3330 && command->argv == NULL
3331 && command->redirects == NULL
3333 debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
3334 return pi->num_cmds;
3337 debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
3339 debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
3342 /* Only real trickiness here is that the uncommitted
3343 * command structure is not counted in pi->num_cmds. */
3344 pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
3345 command = &pi->cmds[pi->num_cmds];
3346 memset(command, 0, sizeof(*command));
3348 ctx->command = command;
3349 /* but ctx->pipe and ctx->list_head remain unchanged */
3351 return pi->num_cmds; /* used only for 0/nonzero check */
3354 static void done_pipe(struct parse_context *ctx, pipe_style type)
3358 debug_printf_parse("done_pipe entered, followup %d\n", type);
3359 /* Close previous command */
3360 not_null = done_command(ctx);
3361 ctx->pipe->followup = type;
3362 IF_HAS_KEYWORDS(ctx->pipe->pi_inverted = ctx->ctx_inverted;)
3363 IF_HAS_KEYWORDS(ctx->ctx_inverted = 0;)
3364 IF_HAS_KEYWORDS(ctx->pipe->res_word = ctx->ctx_res_w;)
3366 /* Without this check, even just <enter> on command line generates
3367 * tree of three NOPs (!). Which is harmless but annoying.
3368 * IOW: it is safe to do it unconditionally.
3369 * RES_NONE case is for "for a in; do ..." (empty IN set)
3370 * to work, possibly other cases too. */
3371 if (not_null IF_HAS_KEYWORDS(|| ctx->ctx_res_w != RES_NONE)) {
3373 debug_printf_parse("done_pipe: adding new pipe: "
3374 "not_null:%d ctx->ctx_res_w:%d\n",
3375 not_null, ctx->ctx_res_w);
3377 ctx->pipe->next = new_p;
3379 /* RES_THEN, RES_DO etc are "sticky" -
3380 * they remain set for commands inside if/while.
3381 * This is used to control execution.
3382 * RES_FOR and RES_IN are NOT sticky (needed to support
3383 * cases where variable or value happens to match a keyword):
3385 #if ENABLE_HUSH_LOOPS
3386 if (ctx->ctx_res_w == RES_FOR
3387 || ctx->ctx_res_w == RES_IN)
3388 ctx->ctx_res_w = RES_NONE;
3390 #if ENABLE_HUSH_CASE
3391 if (ctx->ctx_res_w == RES_MATCH)
3392 ctx->ctx_res_w = RES_CASEI;
3394 ctx->command = NULL; /* trick done_command below */
3395 /* Create the memory for command, roughly:
3396 * ctx->pipe->cmds = new struct command;
3397 * ctx->command = &ctx->pipe->cmds[0];
3401 debug_printf_parse("done_pipe return\n");
3404 static void initialize_context(struct parse_context *ctx)
3406 memset(ctx, 0, sizeof(*ctx));
3407 ctx->pipe = ctx->list_head = new_pipe();
3408 /* Create the memory for command, roughly:
3409 * ctx->pipe->cmds = new struct command;
3410 * ctx->command = &ctx->pipe->cmds[0];
3416 /* If a reserved word is found and processed, parse context is modified
3417 * and 1 is returned.
3420 struct reserved_combo {
3423 unsigned char assignment_flag;
3427 FLAG_END = (1 << RES_NONE ),
3429 FLAG_IF = (1 << RES_IF ),
3430 FLAG_THEN = (1 << RES_THEN ),
3431 FLAG_ELIF = (1 << RES_ELIF ),
3432 FLAG_ELSE = (1 << RES_ELSE ),
3433 FLAG_FI = (1 << RES_FI ),
3435 #if ENABLE_HUSH_LOOPS
3436 FLAG_FOR = (1 << RES_FOR ),
3437 FLAG_WHILE = (1 << RES_WHILE),
3438 FLAG_UNTIL = (1 << RES_UNTIL),
3439 FLAG_DO = (1 << RES_DO ),
3440 FLAG_DONE = (1 << RES_DONE ),
3441 FLAG_IN = (1 << RES_IN ),
3443 #if ENABLE_HUSH_CASE
3444 FLAG_MATCH = (1 << RES_MATCH),
3445 FLAG_ESAC = (1 << RES_ESAC ),
3447 FLAG_START = (1 << RES_XXXX ),
3450 static const struct reserved_combo* match_reserved_word(o_string *word)
3452 /* Mostly a list of accepted follow-up reserved words.
3453 * FLAG_END means we are done with the sequence, and are ready
3454 * to turn the compound list into a command.
3455 * FLAG_START means the word must start a new compound list.
3457 static const struct reserved_combo reserved_list[] = {
3459 { "!", RES_NONE, NOT_ASSIGNMENT , 0 },
3460 { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START },
3461 { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
3462 { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN },
3463 { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI },
3464 { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
3466 #if ENABLE_HUSH_LOOPS
3467 { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
3468 { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3469 { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3470 { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
3471 { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE },
3472 { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
3474 #if ENABLE_HUSH_CASE
3475 { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
3476 { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
3479 const struct reserved_combo *r;
3481 for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
3482 if (strcmp(word->data, r->literal) == 0)
3487 static int reserved_word(o_string *word, struct parse_context *ctx)
3489 #if ENABLE_HUSH_CASE
3490 static const struct reserved_combo reserved_match = {
3491 "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
3494 const struct reserved_combo *r;
3496 r = match_reserved_word(word);
3500 debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
3501 #if ENABLE_HUSH_CASE
3502 if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE)
3503 /* "case word IN ..." - IN part starts first match part */
3504 r = &reserved_match;
3507 if (r->flag == 0) { /* '!' */
3508 if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
3509 syntax("! ! command");
3510 IF_HAS_KEYWORDS(ctx->ctx_res_w = RES_SNTX;)
3512 ctx->ctx_inverted = 1;
3515 if (r->flag & FLAG_START) {
3516 struct parse_context *old;
3517 old = xmalloc(sizeof(*old));
3518 debug_printf_parse("push stack %p\n", old);
3519 *old = *ctx; /* physical copy */
3520 initialize_context(ctx);
3522 } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
3524 ctx->ctx_res_w = RES_SNTX;
3527 ctx->ctx_res_w = r->res;
3528 ctx->old_flag = r->flag;
3529 if (ctx->old_flag & FLAG_END) {
3530 struct parse_context *old;
3531 done_pipe(ctx, PIPE_SEQ);
3532 debug_printf_parse("pop stack %p\n", ctx->stack);
3534 old->command->group = ctx->list_head;
3535 old->command->grp_type = GRP_NORMAL;
3536 *ctx = *old; /* physical copy */
3539 word->o_assignment = r->assignment_flag;
3544 /* Word is complete, look at it and update parsing context.
3545 * Normal return is 0. Syntax errors return 1.
3546 * Note: on return, word is reset, but not o_free'd!
3548 static int done_word(o_string *word, struct parse_context *ctx)
3550 struct command *command = ctx->command;
3552 debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
3553 if (word->length == 0 && word->nonnull == 0) {
3554 debug_printf_parse("done_word return 0: true null, ignored\n");
3557 /* If this word wasn't an assignment, next ones definitely
3558 * can't be assignments. Even if they look like ones. */
3559 if (word->o_assignment != DEFINITELY_ASSIGNMENT
3560 && word->o_assignment != WORD_IS_KEYWORD
3562 word->o_assignment = NOT_ASSIGNMENT;
3564 if (word->o_assignment == DEFINITELY_ASSIGNMENT)
3565 command->assignment_cnt++;
3566 word->o_assignment = MAYBE_ASSIGNMENT;
3569 if (ctx->pending_redirect) {
3570 /* We do not glob in e.g. >*.tmp case. bash seems to glob here
3571 * only if run as "bash", not "sh" */
3572 ctx->pending_redirect->rd_filename = xstrdup(word->data);
3573 word->o_assignment = NOT_ASSIGNMENT;
3574 debug_printf("word stored in rd_filename: '%s'\n", word->data);
3576 /* "{ echo foo; } echo bar" - bad */
3577 /* NB: bash allows e.g.:
3578 * if true; then { echo foo; } fi
3579 * while if false; then false; fi do break; done
3581 if (command->group) {
3583 debug_printf_parse("done_word return 1: syntax error, "
3584 "groups and arglists don't mix\n");
3588 #if ENABLE_HUSH_CASE
3589 if (ctx->ctx_dsemicolon
3590 && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
3592 /* already done when ctx_dsemicolon was set to 1: */
3593 /* ctx->ctx_res_w = RES_MATCH; */
3594 ctx->ctx_dsemicolon = 0;
3597 if (!command->argv /* if it's the first word... */
3598 #if ENABLE_HUSH_LOOPS
3599 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
3600 && ctx->ctx_res_w != RES_IN
3603 debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
3604 if (reserved_word(word, ctx)) {
3606 debug_printf_parse("done_word return %d\n", (ctx->ctx_res_w == RES_SNTX));
3607 return (ctx->ctx_res_w == RES_SNTX);
3611 if (word->nonnull /* word had "xx" or 'xx' at least as part of it. */
3612 /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
3613 && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
3614 /* (otherwise it's known to be not empty and is already safe) */
3616 /* exclude "$@" - it can expand to no word despite "" */
3617 char *p = word->data;
3618 while (p[0] == SPECIAL_VAR_SYMBOL
3619 && (p[1] & 0x7f) == '@'
3620 && p[2] == SPECIAL_VAR_SYMBOL
3624 if (p == word->data || p[0] != '\0') {
3625 /* saw no "$@", or not only "$@" but some
3626 * real text is there too */
3627 /* insert "empty variable" reference, this makes
3628 * e.g. "", $empty"" etc to not disappear */
3629 o_addchr(word, SPECIAL_VAR_SYMBOL);
3630 o_addchr(word, SPECIAL_VAR_SYMBOL);
3633 command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
3634 debug_print_strings("word appended to argv", command->argv);
3638 ctx->pending_redirect = NULL;
3640 #if ENABLE_HUSH_LOOPS
3641 /* Force FOR to have just one word (variable name) */
3642 /* NB: basically, this makes hush see "for v in ..." syntax as if
3643 * as it is "for v; in ...". FOR and IN become two pipe structs
3645 if (ctx->ctx_res_w == RES_FOR) {
3646 //TODO: check that command->argv[0] is a valid variable name!
3647 done_pipe(ctx, PIPE_SEQ);
3650 #if ENABLE_HUSH_CASE
3651 /* Force CASE to have just one word */
3652 if (ctx->ctx_res_w == RES_CASE) {
3653 done_pipe(ctx, PIPE_SEQ);
3656 debug_printf_parse("done_word return 0\n");
3660 /* If a redirect is immediately preceded by a number, that number is
3661 * supposed to tell which file descriptor to redirect. This routine
3662 * looks for such preceding numbers. In an ideal world this routine
3663 * needs to handle all the following classes of redirects...
3664 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
3665 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
3666 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
3667 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
3668 * A -1 output from this program means no valid number was found, so the
3669 * caller should use the appropriate default for this redirection.
3671 static int redirect_opt_num(o_string *o)
3677 for (num = 0; num < o->length; num++) {
3678 if (!isdigit(o->data[num])) {
3682 num = atoi(o->data);
3687 static struct pipe *parse_stream(struct in_str *input, int end_trigger);
3688 static void parse_and_run_string(const char *s);
3690 #if ENABLE_HUSH_TICK
3691 static FILE *generate_stream_from_string(const char *s)
3694 int pid, channel[2];
3697 pid = BB_MMU ? fork() : vfork();
3699 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
3701 if (pid == 0) { /* child */
3702 /* Process substitution is not considered to be usual
3703 * 'command execution'.
3704 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
3711 if (ENABLE_HUSH_JOB)
3712 die_sleep = 0; /* let nofork's xfuncs die */
3713 close(channel[0]); /* NB: close _first_, then move fd! */
3714 xmove_fd(channel[1], 1);
3715 /* Prevent it from trying to handle ctrl-z etc */
3716 USE_HUSH_JOB(G.run_list_level = 1;)
3718 parse_and_run_string(s);
3719 _exit(G.last_return_code);
3721 /* We re-execute after vfork on NOMMU. This makes this script safe:
3722 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >TESTFILE
3723 * huge=`cat TESTFILE` # was blocking here forever
3726 //TODO: pass non-exported variables, traps, and functions
3727 execl(CONFIG_BUSYBOX_EXEC_PATH, "hush", "-c", s, NULL);
3734 pf = fdopen(channel[0], "r");
3738 /* Return code is exit status of the process that is run. */
3739 static int process_command_subs(o_string *dest, const char *s)
3742 struct in_str pipe_str;
3745 pf = generate_stream_from_string(s);
3748 close_on_exec_on(fileno(pf));
3750 /* Now send results of command back into original context */
3751 setup_file_in_str(&pipe_str, pf);
3753 while ((ch = i_getch(&pipe_str)) != EOF) {
3759 o_addchr(dest, '\n');
3762 o_addQchr(dest, ch);
3765 debug_printf("done reading from pipe, pclose()ing\n");
3766 /* Note: we got EOF, and we just close the read end of the pipe.
3767 * We do not wait for the `cmd` child to terminate. bash and ash do.
3769 * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec
3770 * `false`; echo $? - bash outputs "1"
3773 debug_printf("closed FILE from child. return 0\n");
3778 static int parse_group(o_string *dest, struct parse_context *ctx,
3779 struct in_str *input, int ch)
3781 /* dest contains characters seen prior to ( or {.
3782 * Typically it's empty, but for function defs,
3783 * it contains function name (without '()'). */
3784 struct pipe *pipe_list;
3786 struct command *command = ctx->command;
3788 debug_printf_parse("parse_group entered\n");
3789 #if ENABLE_HUSH_FUNCTIONS
3790 if (ch == 'F') { /* function definition? */
3791 bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
3792 //command->fname = dest->data;
3793 command->grp_type = GRP_FUNCTION;
3794 //TODO: review every o_reset() location... do they handle all o_string fields correctly?
3795 memset(dest, 0, sizeof(*dest));
3798 if (command->argv /* word [word](... */
3799 || dest->length /* word(... */
3800 || dest->nonnull /* ""(... */
3803 debug_printf_parse("parse_group return 1: syntax error, groups and arglists don't mix\n");
3809 command->grp_type = GRP_SUBSHELL;
3811 pipe_list = parse_stream(input, endch);
3812 /* empty ()/{} or parse error? */
3813 if (!pipe_list || pipe_list == ERR_PTR) {
3815 debug_printf_parse("parse_group return 1: parse_stream returned %p\n", pipe_list);
3818 command->group = pipe_list;
3819 debug_printf_parse("parse_group return 0\n");
3821 /* command remains "open", available for possible redirects */
3824 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
3825 /* Subroutines for copying $(...) and `...` things */
3826 static void add_till_backquote(o_string *dest, struct in_str *input);
3828 static void add_till_single_quote(o_string *dest, struct in_str *input)
3831 int ch = i_getch(input);
3839 /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
3840 static void add_till_double_quote(o_string *dest, struct in_str *input)
3843 int ch = i_getch(input);
3846 if (ch == '\\') { /* \x. Copy both chars. */
3848 ch = i_getch(input);
3854 add_till_backquote(dest, input);
3858 //if (ch == '$') ...
3861 /* Process `cmd` - copy contents until "`" is seen. Complicated by
3863 * "Within the backquoted style of command substitution, backslash
3864 * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
3865 * The search for the matching backquote shall be satisfied by the first
3866 * backquote found without a preceding backslash; during this search,
3867 * if a non-escaped backquote is encountered within a shell comment,
3868 * a here-document, an embedded command substitution of the $(command)
3869 * form, or a quoted string, undefined results occur. A single-quoted
3870 * or double-quoted string that begins, but does not end, within the
3871 * "`...`" sequence produces undefined results."
3873 * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
3875 static void add_till_backquote(o_string *dest, struct in_str *input)
3878 int ch = i_getch(input);
3881 if (ch == '\\') { /* \x. Copy both chars unless it is \` */
3882 int ch2 = i_getch(input);
3883 if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
3892 /* Process $(cmd) - copy contents until ")" is seen. Complicated by
3893 * quoting and nested ()s.
3894 * "With the $(command) style of command substitution, all characters
3895 * following the open parenthesis to the matching closing parenthesis
3896 * constitute the command. Any valid shell script can be used for command,
3897 * except a script consisting solely of redirections which produces
3898 * unspecified results."
3900 * echo $(echo '(TEST)' BEST) (TEST) BEST
3901 * echo $(echo 'TEST)' BEST) TEST) BEST
3902 * echo $(echo \(\(TEST\) BEST) ((TEST) BEST
3904 static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
3908 int ch = i_getch(input);
3917 if (i_peek(input) == ')') {
3924 add_till_single_quote(dest, input);
3929 add_till_double_quote(dest, input);
3933 if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */
3934 ch = i_getch(input);
3942 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
3944 /* Return code: 0 for OK, 1 for syntax error */
3945 static int handle_dollar(o_string *dest, struct in_str *input)
3948 int ch = i_peek(input); /* first character after the $ */
3949 unsigned char quote_mask = dest->o_escape ? 0x80 : 0;
3951 debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
3955 o_addchr(dest, SPECIAL_VAR_SYMBOL);
3957 debug_printf_parse(": '%c'\n", ch);
3958 o_addchr(dest, ch | quote_mask);
3961 if (!isalnum(ch) && ch != '_')
3965 o_addchr(dest, SPECIAL_VAR_SYMBOL);
3966 } else if (isdigit(ch)) {
3969 o_addchr(dest, SPECIAL_VAR_SYMBOL);
3970 debug_printf_parse(": '%c'\n", ch);
3971 o_addchr(dest, ch | quote_mask);
3972 o_addchr(dest, SPECIAL_VAR_SYMBOL);
3973 } else switch (ch) {
3975 case '!': /* last bg pid */
3976 case '?': /* last exit code */
3977 case '#': /* number of args */
3978 case '*': /* args */
3979 case '@': /* args */
3980 goto make_one_char_var;
3982 bool first_char, all_digits;
3984 o_addchr(dest, SPECIAL_VAR_SYMBOL);
3986 /* XXX maybe someone will try to escape the '}' */
3991 ch = i_getch(input);
3997 /* ${#var}: length of var contents */
3999 else if (isdigit(ch)) {
4005 if (expansion < 2 &&
4006 ((all_digits && !isdigit(ch)) ||
4007 (!all_digits && !isalnum(ch) && ch != '_')))
4009 /* handle parameter expansions
4010 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
4015 case ':': /* null modifier */
4016 if (expansion == 0) {
4017 debug_printf_parse(": null modifier\n");
4023 #if 0 /* not implemented yet :( */
4024 case '#': /* remove prefix */
4025 case '%': /* remove suffix */
4026 if (expansion == 0) {
4027 debug_printf_parse(": remove suffix/prefix\n");
4034 case '-': /* default value */
4035 case '=': /* assign default */
4036 case '+': /* alternative */
4037 case '?': /* error indicate */
4038 debug_printf_parse(": parameter expansion\n");
4044 syntax("unterminated ${name}");
4045 debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
4051 debug_printf_parse(": '%c'\n", ch);
4052 o_addchr(dest, ch | quote_mask);
4056 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4062 #if ENABLE_SH_MATH_SUPPORT
4063 if (i_peek(input) == '(') {
4065 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4066 o_addchr(dest, /*quote_mask |*/ '+');
4067 add_till_closing_paren(dest, input, true);
4068 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4073 #if ENABLE_HUSH_TICK
4074 //int pos = dest->length;
4075 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4076 o_addchr(dest, quote_mask | '`');
4077 add_till_closing_paren(dest, input, false);
4078 //debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
4079 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4086 if (isalnum(ch)) { /* it's $_name or $_123 */
4092 /* still unhandled, but should be eventually */
4093 bb_error_msg("unhandled syntax: $%c", ch);
4097 o_addQchr(dest, '$');
4099 debug_printf_parse("handle_dollar return 0\n");
4103 static int parse_stream_dquoted(o_string *dest, struct in_str *input, int dquote_end)
4109 ch = i_getch(input);
4110 if (ch == dquote_end) { /* may be only '"' or EOF */
4112 if (dest->o_assignment == NOT_ASSIGNMENT)
4113 dest->o_escape ^= 1;
4114 debug_printf_parse("parse_stream_dquoted return 0\n");
4118 syntax("unterminated \"");
4119 debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n");
4124 next = i_peek(input);
4126 debug_printf_parse(": ch=%c (%d) m=%d escape=%d\n",
4127 ch, ch, m, dest->o_escape);
4131 debug_printf_parse("parse_stream_dquoted return 1: \\<eof>\n");
4135 * "The backslash retains its special meaning [in "..."]
4136 * only when followed by one of the following characters:
4137 * $, `, ", \, or <newline>. A double quote may be quoted
4138 * within double quotes by preceding it with a backslash.
4139 * If enabled, history expansion will be performed unless
4140 * an ! appearing in double quotes is escaped using
4141 * a backslash. The backslash preceding the ! is not removed."
4143 if (strchr("$`\"\\", next) != NULL) {
4144 o_addqchr(dest, i_getch(input));
4146 o_addqchr(dest, '\\');
4151 if (handle_dollar(dest, input) != 0) {
4152 debug_printf_parse("parse_stream_dquoted return 1: handle_dollar returned non-0\n");
4157 #if ENABLE_HUSH_TICK
4159 //int pos = dest->length;
4160 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4161 o_addchr(dest, 0x80 | '`');
4162 add_till_backquote(dest, input);
4163 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4164 //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
4168 o_addQchr(dest, ch);
4170 && (dest->o_assignment == MAYBE_ASSIGNMENT
4171 || dest->o_assignment == WORD_IS_KEYWORD)
4172 && is_assignment(dest->data)
4174 dest->o_assignment = DEFINITELY_ASSIGNMENT;
4180 * Scan input until EOF or end_trigger char.
4181 * Return a list of pipes to execute, or NULL on EOF
4182 * or if end_trigger character is met.
4183 * On syntax error, exit is shell is not interactive,
4184 * reset parsing machinery and start parsing anew,
4185 * or return ERR_PTR.
4187 static struct pipe *parse_stream(struct in_str *input, int end_trigger)
4189 struct parse_context ctx;
4190 o_string dest = NULL_O_STRING;
4195 redir_type redir_style;
4197 /* Double-quote state is handled in the state variable is_in_dquote.
4198 * A single-quote triggers a bypass of the main loop until its mate is
4199 * found. When recursing, quote state is passed in via dest->o_escape. */
4201 debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
4202 end_trigger ? : 'X');
4204 G.ifs = get_local_var_value("IFS");
4209 #if ENABLE_HUSH_INTERACTIVE
4210 input->promptmode = 0; /* PS1 */
4212 /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */
4213 initialize_context(&ctx);
4217 const char *is_special;
4220 if (parse_stream_dquoted(&dest, input, '"')) {
4223 /* We reached closing '"' */
4227 ch = i_getch(input);
4228 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4229 ch, ch, dest.o_escape);
4232 if (done_word(&dest, &ctx)) {
4236 done_pipe(&ctx, PIPE_SEQ);
4237 /* If we got nothing... */
4239 if (pi->num_cmds == 0
4240 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
4242 free_pipe_list(pi, 0);
4245 debug_printf_parse("parse_stream return %p\n", pi);
4249 next = i_peek(input);
4252 is_ifs = strchr(G.ifs, ch);
4253 is_special = strchr("<>;&|(){}#'" /* special outside of "str" */
4254 "\\$\"" USE_HUSH_TICK("`") /* always special */
4257 if (!is_special && !is_ifs) { /* ordinary char */
4258 o_addQchr(&dest, ch);
4259 if ((dest.o_assignment == MAYBE_ASSIGNMENT
4260 || dest.o_assignment == WORD_IS_KEYWORD)
4262 && is_assignment(dest.data)
4264 dest.o_assignment = DEFINITELY_ASSIGNMENT;
4270 if (done_word(&dest, &ctx)) {
4274 #if ENABLE_HUSH_CASE
4275 /* "case ... in <newline> word) ..." -
4276 * newlines are ignored (but ';' wouldn't be) */
4277 if (ctx.command->argv == NULL
4278 && ctx.ctx_res_w == RES_MATCH
4283 /* Treat newline as a command separator. */
4284 done_pipe(&ctx, PIPE_SEQ);
4285 dest.o_assignment = MAYBE_ASSIGNMENT;
4287 /* note: if (is_ifs) continue;
4288 * will still trigger for us */
4291 if (end_trigger && end_trigger == ch) {
4292 //TODO: disallow "{ cmd }" without semicolon
4293 if (done_word(&dest, &ctx)) {
4296 done_pipe(&ctx, PIPE_SEQ);
4297 dest.o_assignment = MAYBE_ASSIGNMENT;
4298 /* Do we sit outside of any if's, loops or case's? */
4300 IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
4302 debug_printf_parse("parse_stream return %p: "
4303 "end_trigger char found\n",
4306 return ctx.list_head;
4312 if (dest.o_assignment == MAYBE_ASSIGNMENT) {
4313 /* ch is a special char and thus this word
4314 * cannot be an assignment */
4315 dest.o_assignment = NOT_ASSIGNMENT;
4320 if (dest.length == 0) {
4323 if (ch == EOF || ch == '\n')
4328 o_addQchr(&dest, ch);
4336 o_addchr(&dest, '\\');
4337 o_addchr(&dest, i_getch(input));
4340 if (handle_dollar(&dest, input) != 0) {
4341 debug_printf_parse("parse_stream parse error: handle_dollar returned non-0\n");
4348 ch = i_getch(input);
4350 syntax("unterminated '");
4355 if (dest.o_assignment == NOT_ASSIGNMENT)
4356 o_addqchr(&dest, ch);
4358 o_addchr(&dest, ch);
4363 is_in_dquote ^= 1; /* invert */
4364 if (dest.o_assignment == NOT_ASSIGNMENT)
4367 #if ENABLE_HUSH_TICK
4369 //int pos = dest.length;
4370 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4371 o_addchr(&dest, '`');
4372 add_till_backquote(&dest, input);
4373 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4374 //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos);
4379 redir_fd = redirect_opt_num(&dest);
4380 if (done_word(&dest, &ctx)) {
4383 redir_style = REDIRECT_OVERWRITE;
4385 redir_style = REDIRECT_APPEND;
4389 else if (next == '(') {
4390 syntax(">(process) not supported");
4394 setup_redirect(&ctx, redir_fd, redir_style, input);
4397 redir_fd = redirect_opt_num(&dest);
4398 if (done_word(&dest, &ctx)) {
4401 redir_style = REDIRECT_INPUT;
4403 redir_style = REDIRECT_HEREIS;
4405 } else if (next == '>') {
4406 redir_style = REDIRECT_IO;
4410 else if (next == '(') {
4411 syntax("<(process) not supported");
4415 setup_redirect(&ctx, redir_fd, redir_style, input);
4418 #if ENABLE_HUSH_CASE
4421 if (done_word(&dest, &ctx)) {
4424 done_pipe(&ctx, PIPE_SEQ);
4425 #if ENABLE_HUSH_CASE
4426 /* Eat multiple semicolons, detect
4427 * whether it means something special */
4433 if (ctx.ctx_res_w == RES_CASEI) {
4434 ctx.ctx_dsemicolon = 1;
4435 ctx.ctx_res_w = RES_MATCH;
4441 /* We just finished a cmd. New one may start
4442 * with an assignment */
4443 dest.o_assignment = MAYBE_ASSIGNMENT;
4446 if (done_word(&dest, &ctx)) {
4451 done_pipe(&ctx, PIPE_AND);
4453 done_pipe(&ctx, PIPE_BG);
4457 if (done_word(&dest, &ctx)) {
4460 #if ENABLE_HUSH_CASE
4461 if (ctx.ctx_res_w == RES_MATCH)
4462 break; /* we are in case's "word | word)" */
4464 if (next == '|') { /* || */
4466 done_pipe(&ctx, PIPE_OR);
4468 /* we could pick up a file descriptor choice here
4469 * with redirect_opt_num(), but bash doesn't do it.
4470 * "echo foo 2| cat" yields "foo 2". */
4475 #if ENABLE_HUSH_CASE
4476 /* "case... in [(]word)..." - skip '(' */
4477 if (ctx.ctx_res_w == RES_MATCH
4478 && ctx.command->argv == NULL /* not (word|(... */
4479 && dest.length == 0 /* not word(... */
4480 && dest.nonnull == 0 /* not ""(... */
4485 #if ENABLE_HUSH_FUNCTIONS
4486 if (dest.length != 0 /* not just () but word() */
4487 && dest.nonnull == 0 /* not a"b"c() */
4488 && ctx.command->argv == NULL /* it's the first word */
4489 //TODO: "func ( ) {...}" - note spaces - is valid format too in bash
4490 && i_peek(input) == ')'
4491 && !match_reserved_word(&dest)
4493 bb_error_msg("seems like a function definition");
4496 //TODO: do it properly.
4497 ch = i_getch(input);
4498 } while (ch == ' ' || ch == '\n');
4500 syntax("was expecting {");
4503 ch = 'F'; /* magic value */
4507 if (parse_group(&dest, &ctx, input, ch) != 0) {
4512 #if ENABLE_HUSH_CASE
4513 if (ctx.ctx_res_w == RES_MATCH)
4517 /* proper use of this character is caught by end_trigger:
4518 * if we see {, we call parse_group(..., end_trigger='}')
4519 * and it will match } earlier (not here). */
4520 syntax("unexpected } or )");
4524 bb_error_msg_and_die("BUG: unexpected %c\n", ch);
4530 struct parse_context *pctx;
4531 IF_HAS_KEYWORDS(struct parse_context *p2;)
4533 /* Clean up allocated tree.
4534 * Samples for finding leaks on syntax error recovery path.
4535 * Execute them from interactive shell and watch pmap `pidof hush`.
4536 * while if false; then false; fi do break; done (bash accepts it)
4537 * while if false; then false; fi; do break; fi
4541 /* Update pipe/command counts,
4542 * otherwise freeing may miss some */
4543 done_pipe(pctx, PIPE_SEQ);
4544 debug_printf_clean("freeing list %p from ctx %p\n",
4545 pctx->list_head, pctx);
4546 debug_print_tree(pctx->list_head, 0);
4547 free_pipe_list(pctx->list_head, 0);
4548 debug_printf_clean("freed list %p\n", pctx->list_head);
4549 IF_HAS_KEYWORDS(p2 = pctx->stack;)
4553 IF_HAS_KEYWORDS(pctx = p2;)
4554 } while (HAS_KEYWORDS && pctx);
4555 /* Free text, clear all dest fields */
4557 /* If we are not in top-level parse, we return,
4558 * our caller will propagate error.
4560 if (end_trigger != ';')
4562 /* Discard cached input, force prompt */
4564 USE_HUSH_INTERACTIVE(input->promptme = 1;)
4569 /* Execiting from string: eval, sh -c '...'
4570 * or from file: /etc/profile, . file, sh <script>, sh (intereactive)
4571 * end_trigger controls how often we stop parsing
4572 * NUL: parse all, execute, return
4573 * ';': parse till ';' or newline, execute, repeat till EOF
4575 static void parse_and_run_stream(struct in_str *inp, int end_trigger)
4578 struct pipe *pipe_list;
4580 pipe_list = parse_stream(inp, end_trigger);
4581 if (!pipe_list) /* EOF */
4583 debug_print_tree(pipe_list, 0);
4584 debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
4585 run_and_free_list(pipe_list);
4589 static void parse_and_run_string(const char *s)
4591 struct in_str input;
4592 setup_string_in_str(&input, s);
4593 parse_and_run_stream(&input, '\0');
4596 static void parse_and_run_file(FILE *f)
4598 struct in_str input;
4599 setup_file_in_str(&input, f);
4600 parse_and_run_stream(&input, ';');
4604 /* Make sure we have a controlling tty. If we get started under a job
4605 * aware app (like bash for example), make sure we are now in charge so
4606 * we don't fight over who gets the foreground */
4607 static void setup_job_control(void)
4611 shell_pgrp = getpgrp();
4613 /* If we were ran as 'hush &',
4614 * sleep until we are in the foreground. */
4615 while (tcgetpgrp(G_interactive_fd) != shell_pgrp) {
4616 /* Send TTIN to ourself (should stop us) */
4617 kill(- shell_pgrp, SIGTTIN);
4618 shell_pgrp = getpgrp();
4621 /* We _must_ restore tty pgrp on fatal signals */
4622 set_fatal_signals_to_sigexit();
4624 /* Put ourselves in our own process group. */
4625 bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
4626 /* Grab control of the terminal. */
4627 tcsetpgrp(G_interactive_fd, getpid());
4631 static int set_mode(const char cstate, const char mode)
4633 int state = (cstate == '-' ? 1 : 0);
4635 case 'n': G.fake_mode = state; break;
4636 case 'x': /*G.debug_mode = state;*/ break;
4637 default: return EXIT_FAILURE;
4639 return EXIT_SUCCESS;
4642 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
4643 int hush_main(int argc, char **argv)
4645 static const struct variable const_shell_ver = {
4647 .varstr = (char*)hush_version_str,
4648 .max_len = 1, /* 0 can provoke free(name) */
4656 struct variable *cur_var;
4660 G.root_pid = getpid();
4662 /* Deal with HUSH_VERSION */
4663 G.shell_ver = const_shell_ver; /* copying struct here */
4664 G.top_var = &G.shell_ver;
4665 debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
4666 unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
4667 /* Initialize our shell local variables with the values
4668 * currently living in the environment */
4669 cur_var = G.top_var;
4672 char *value = strchr(*e, '=');
4673 if (value) { /* paranoia */
4674 cur_var->next = xzalloc(sizeof(*cur_var));
4675 cur_var = cur_var->next;
4676 cur_var->varstr = *e;
4677 cur_var->max_len = strlen(*e);
4678 cur_var->flg_export = 1;
4682 debug_printf_env("putenv '%s'\n", hush_version_str);
4683 putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
4685 #if ENABLE_FEATURE_EDITING
4686 G.line_input_state = new_line_input_t(FOR_SHELL);
4688 /* XXX what should these be while sourcing /etc/profile? */
4689 G.global_argc = argc;
4690 G.global_argv = argv;
4691 /* Initialize some more globals to non-zero values */
4693 #if ENABLE_HUSH_INTERACTIVE
4694 if (ENABLE_FEATURE_EDITING)
4695 cmdedit_set_initial_prompt();
4699 if (EXIT_SUCCESS) /* otherwise is already done */
4700 G.last_return_code = EXIT_SUCCESS;
4702 if (argv[0] && argv[0][0] == '-') {
4703 debug_printf("sourcing /etc/profile\n");
4704 input = fopen_for_read("/etc/profile");
4705 if (input != NULL) {
4706 close_on_exec_on(fileno(input));
4707 parse_and_run_file(input);
4713 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
4714 while ((opt = getopt(argc, argv, "c:xins")) > 0) {
4717 G.global_argv = argv + optind;
4718 if (!argv[optind]) {
4719 /* -c 'script' (no params): prevent empty $0 */
4720 *--G.global_argv = argv[0];
4722 } /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
4723 G.global_argc = argc - optind;
4724 parse_and_run_string(optarg);
4727 /* Well, we cannot just declare interactiveness,
4728 * we have to have some stuff (ctty, etc) */
4729 /* G_interactive_fd++; */
4732 /* "-s" means "read from stdin", but this is how we always
4733 * operate, so simply do nothing here. */
4737 if (!set_mode('-', opt))
4741 fprintf(stderr, "Usage: sh [FILE]...\n"
4742 " or: sh -c command [args]...\n\n");
4750 /* A shell is interactive if the '-i' flag was given, or if all of
4751 * the following conditions are met:
4753 * no arguments remaining or the -s flag given
4754 * standard input is a terminal
4755 * standard output is a terminal
4756 * Refer to Posix.2, the description of the 'sh' utility. */
4757 if (argv[optind] == NULL && input == stdin
4758 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
4760 G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
4761 debug_printf("saved_tty_pgrp=%d\n", G.saved_tty_pgrp);
4762 if (G.saved_tty_pgrp >= 0) {
4763 /* try to dup to high fd#, >= 255 */
4764 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
4765 if (G_interactive_fd < 0) {
4766 /* try to dup to any fd */
4767 G_interactive_fd = dup(STDIN_FILENO);
4768 if (G_interactive_fd < 0)
4770 G_interactive_fd = 0;
4772 // TODO: track & disallow any attempts of user
4773 // to (inadvertently) close/redirect it
4776 init_signal_mask(); /* note: ensures SIGCHLD is not masked */
4777 debug_printf("interactive_fd=%d\n", G_interactive_fd);
4778 if (G_interactive_fd) {
4779 fcntl(G_interactive_fd, F_SETFD, FD_CLOEXEC);
4780 /* Looks like they want an interactive shell */
4781 setup_job_control();
4782 /* -1 is special - makes xfuncs longjmp, not exit
4783 * (we reset die_sleep = 0 whereever we [v]fork) */
4785 if (setjmp(die_jmp)) {
4786 /* xfunc has failed! die die die */
4787 hush_exit(xfunc_error_retval);
4790 #elif ENABLE_HUSH_INTERACTIVE
4791 /* no job control compiled, only prompt/line editing */
4792 if (argv[optind] == NULL && input == stdin
4793 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
4795 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
4796 if (G_interactive_fd < 0) {
4797 /* try to dup to any fd */
4798 G_interactive_fd = dup(STDIN_FILENO);
4799 if (G_interactive_fd < 0)
4801 G_interactive_fd = 0;
4803 if (G_interactive_fd) {
4804 fcntl(G_interactive_fd, F_SETFD, FD_CLOEXEC);
4807 init_signal_mask(); /* note: ensures SIGCHLD is not masked */
4811 /* POSIX allows shell to re-enable SIGCHLD
4812 * even if it was SIG_IGN on entry */
4813 // G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
4814 signal(SIGCHLD, SIG_DFL); // SIGCHLD_handler);
4816 #if ENABLE_HUSH_INTERACTIVE && !ENABLE_FEATURE_SH_EXTRA_QUIET
4817 if (G_interactive_fd) {
4818 printf("\n\n%s hush - the humble shell v"HUSH_VER_STR"\n", bb_banner);
4819 printf("Enter 'help' for a list of built-in commands.\n\n");
4823 if (argv[optind] == NULL) {
4824 parse_and_run_file(stdin);
4826 debug_printf("\nrunning script '%s'\n", argv[optind]);
4827 G.global_argv = argv + optind;
4828 G.global_argc = argc - optind;
4829 input = xfopen_for_read(argv[optind]);
4830 fcntl(fileno(input), F_SETFD, FD_CLOEXEC);
4831 parse_and_run_file(input);
4836 #if ENABLE_FEATURE_CLEAN_UP
4838 if (G.cwd != bb_msg_unknown)
4840 cur_var = G.top_var->next;
4842 struct variable *tmp = cur_var;
4843 if (!cur_var->max_len)
4844 free(cur_var->varstr);
4845 cur_var = cur_var->next;
4849 hush_exit(G.last_return_code);
4854 int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
4855 int lash_main(int argc, char **argv)
4857 //bb_error_msg("lash is deprecated, please use hush instead");
4858 return hush_main(argc, argv);
4866 static int builtin_trap(char **argv)
4873 G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
4876 /* No args: print all trapped. This isn't 100% correct as we should
4877 * be escaping the cmd so that it can be pasted back in ...
4879 for (i = 0; i < NSIG; ++i)
4881 printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
4882 return EXIT_SUCCESS;
4887 /* if first arg is decimal: reset all specified */
4888 sig = bb_strtou(*++argv, NULL, 10);
4894 sig = get_signum(*argv++);
4895 if (sig < 0 || sig >= NSIG) {
4897 /* mimic bash message exactly */
4898 bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
4903 G.traps[sig] = xstrdup(new_cmd);
4905 debug_printf("trap: setting SIG%s (%i) to '%s'",
4906 get_signame(sig), sig, G.traps[sig]);
4908 /* There is no signal for 0 (EXIT) */
4913 sigaddset(&G.blocked_set, sig);
4915 /* there was a trap handler, we are removing it
4916 * (if sig has non-DFL handling,
4917 * we don't need to do anything) */
4918 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
4920 sigdelset(&G.blocked_set, sig);
4922 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
4927 /* first arg is "-": reset all specified to default */
4928 /* first arg is "": ignore all specified */
4929 /* everything else: execute first arg upon signal */
4931 bb_error_msg("trap: invalid arguments");
4932 return EXIT_FAILURE;
4934 if (LONE_DASH(*argv))
4942 static int builtin_true(char **argv UNUSED_PARAM)
4947 static int builtin_test(char **argv)
4954 return test_main(argc, argv - argc);
4957 static int builtin_echo(char **argv)
4964 return echo_main(argc, argv - argc);
4967 static int builtin_eval(char **argv)
4969 int rcode = EXIT_SUCCESS;
4972 char *str = expand_strvec_to_string(argv + 1);
4974 * eval "echo Hi; done" ("done" is syntax error):
4975 * "echo Hi" will not execute too.
4977 parse_and_run_string(str);
4979 rcode = G.last_return_code;
4984 static int builtin_cd(char **argv)
4987 if (argv[1] == NULL) {
4988 /* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
4989 * bash says "bash: cd: HOME not set" and does nothing (exitcode 1)
4991 newdir = getenv("HOME") ? : "/";
4994 if (chdir(newdir)) {
4995 printf("cd: %s: %s\n", newdir, strerror(errno));
4996 return EXIT_FAILURE;
4999 return EXIT_SUCCESS;
5002 static int builtin_exec(char **argv)
5004 if (argv[1] == NULL)
5005 return EXIT_SUCCESS; /* bash does this */
5010 // FIXME: if exec fails, bash does NOT exit! We do...
5011 pseudo_exec_argv(&dummy, argv + 1, 0, NULL);
5016 static int builtin_exit(char **argv)
5018 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
5019 //puts("exit"); /* bash does it */
5020 // TODO: warn if we have background jobs: "There are stopped jobs"
5021 // On second consecutive 'exit', exit anyway.
5022 if (argv[1] == NULL)
5023 hush_exit(G.last_return_code);
5024 /* mimic bash: exit 123abc == exit 255 + error msg */
5025 xfunc_error_retval = 255;
5026 /* bash: exit -2 == exit 254, no error msg */
5027 hush_exit(xatoi(argv[1]) & 0xff);
5030 static int builtin_export(char **argv)
5033 char *name = argv[1];
5037 // ash emits: export VAR='VAL'
5038 // bash: declare -x VAR="VAL"
5039 // (both also escape as needed (quotes, $, etc))
5044 return EXIT_SUCCESS;
5047 value = strchr(name, '=');
5049 /* They are exporting something without a =VALUE */
5050 struct variable *var;
5052 var = get_local_var(name);
5054 var->flg_export = 1;
5055 debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
5056 putenv(var->varstr);
5058 /* bash does not return an error when trying to export
5059 * an undefined variable. Do likewise. */
5060 return EXIT_SUCCESS;
5063 set_local_var(xstrdup(name), 1);
5064 return EXIT_SUCCESS;
5068 /* built-in 'fg' and 'bg' handler */
5069 static int builtin_fg_bg(char **argv)
5074 if (!G_interactive_fd)
5075 return EXIT_FAILURE;
5076 /* If they gave us no args, assume they want the last backgrounded task */
5078 for (pi = G.job_list; pi; pi = pi->next) {
5079 if (pi->jobid == G.last_jobid) {
5083 bb_error_msg("%s: no current job", argv[0]);
5084 return EXIT_FAILURE;
5086 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
5087 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
5088 return EXIT_FAILURE;
5090 for (pi = G.job_list; pi; pi = pi->next) {
5091 if (pi->jobid == jobnum) {
5095 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
5096 return EXIT_FAILURE;
5098 // TODO: bash prints a string representation
5099 // of job being foregrounded (like "sleep 1 | cat")
5100 if (*argv[0] == 'f') {
5101 /* Put the job into the foreground. */
5102 tcsetpgrp(G_interactive_fd, pi->pgrp);
5105 /* Restart the processes in the job */
5106 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
5107 for (i = 0; i < pi->num_cmds; i++) {
5108 debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
5109 pi->cmds[i].is_stopped = 0;
5111 pi->stopped_cmds = 0;
5113 i = kill(- pi->pgrp, SIGCONT);
5115 if (errno == ESRCH) {
5116 delete_finished_bg_job(pi);
5117 return EXIT_SUCCESS;
5119 bb_perror_msg("kill (SIGCONT)");
5123 if (*argv[0] == 'f') {
5125 return checkjobs_and_fg_shell(pi);
5127 return EXIT_SUCCESS;
5131 #if ENABLE_HUSH_HELP
5132 static int builtin_help(char **argv UNUSED_PARAM)
5134 const struct built_in_command *x;
5136 printf("\nBuilt-in commands:\n");
5137 printf("-------------------\n");
5138 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
5139 printf("%s\t%s\n", x->cmd, x->descr);
5142 return EXIT_SUCCESS;
5147 static int builtin_jobs(char **argv UNUSED_PARAM)
5150 const char *status_string;
5152 for (job = G.job_list; job; job = job->next) {
5153 if (job->alive_cmds == job->stopped_cmds)
5154 status_string = "Stopped";
5156 status_string = "Running";
5158 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
5160 return EXIT_SUCCESS;
5164 static int builtin_pwd(char **argv UNUSED_PARAM)
5167 return EXIT_SUCCESS;
5170 static int builtin_read(char **argv)
5173 const char *name = argv[1] ? argv[1] : "REPLY";
5175 string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
5176 return set_local_var(string, 0);
5179 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
5180 * built-in 'set' handler
5182 * set [-abCefhmnuvx] [-o option] [argument...]
5183 * set [+abCefhmnuvx] [+o option] [argument...]
5184 * set -- [argument...]
5187 * Implementations shall support the options in both their hyphen and
5188 * plus-sign forms. These options can also be specified as options to sh.
5190 * Write out all variables and their values: set
5191 * Set $1, $2, and $3 and set "$#" to 3: set c a b
5192 * Turn on the -x and -v options: set -xv
5193 * Unset all positional parameters: set --
5194 * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
5195 * Set the positional parameters to the expansion of x, even if x expands
5196 * with a leading '-' or '+': set -- $x
5198 * So far, we only support "set -- [argument...]" and some of the short names.
5200 static int builtin_set(char **argv)
5203 char **pp, **g_argv;
5204 char *arg = *++argv;
5208 for (e = G.top_var; e; e = e->next)
5210 return EXIT_SUCCESS;
5214 if (!strcmp(arg, "--")) {
5219 if (arg[0] == '+' || arg[0] == '-') {
5220 for (n = 1; arg[n]; ++n)
5221 if (set_mode(arg[0], arg[n]))
5227 } while ((arg = *++argv) != NULL);
5228 /* Now argv[0] is 1st argument */
5230 /* Only reset global_argv if we didn't process anything */
5232 return EXIT_SUCCESS;
5235 /* NB: G.global_argv[0] ($0) is never freed/changed */
5236 g_argv = G.global_argv;
5237 if (G.global_args_malloced) {
5243 G.global_args_malloced = 1;
5244 pp = xzalloc(sizeof(pp[0]) * 2);
5245 pp[0] = g_argv[0]; /* retain $0 */
5248 /* This realloc's G.global_argv */
5249 G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
5256 return EXIT_SUCCESS;
5258 /* Nothing known, so abort */
5260 bb_error_msg("set: %s: invalid option", arg);
5261 return EXIT_FAILURE;
5264 static int builtin_shift(char **argv)
5270 if (n >= 0 && n < G.global_argc) {
5271 if (G.global_args_malloced) {
5274 free(G.global_argv[m++]);
5277 memmove(&G.global_argv[1], &G.global_argv[n+1],
5278 G.global_argc * sizeof(G.global_argv[0]));
5279 return EXIT_SUCCESS;
5281 return EXIT_FAILURE;
5284 static int builtin_source(char **argv)
5288 if (argv[1] == NULL)
5289 return EXIT_FAILURE;
5291 /* XXX search through $PATH is missing */
5292 input = fopen_for_read(argv[1]);
5294 bb_error_msg("can't open '%s'", argv[1]);
5295 return EXIT_FAILURE;
5297 close_on_exec_on(fileno(input));
5299 /* Now run the file */
5300 /* XXX argv and argc are broken; need to save old G.global_argv
5301 * (pointer only is OK!) on this stack frame,
5302 * set G.global_argv=argv+1, recurse, and restore. */
5303 parse_and_run_file(input);
5305 return G.last_return_code;
5308 static int builtin_umask(char **argv)
5311 const char *arg = argv[1];
5313 new_umask = bb_strtou(arg, NULL, 8);
5315 return EXIT_FAILURE;
5317 new_umask = umask(0);
5318 printf("%.3o\n", (unsigned) new_umask);
5321 return EXIT_SUCCESS;
5324 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
5325 static int builtin_unset(char **argv)
5332 return EXIT_SUCCESS;
5335 if (argv[1][0] == '-') {
5336 switch (argv[1][1]) {
5338 case 'f': if (ENABLE_HUSH_FUNCTIONS) { var = false; break; }
5340 bb_error_msg("unset: %s: invalid option", argv[1]);
5341 return EXIT_FAILURE;
5349 if (unset_local_var(argv[i]))
5352 #if ENABLE_HUSH_FUNCTIONS
5354 unset_local_func(argv[i]);
5360 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
5361 static int builtin_wait(char **argv)
5363 int ret = EXIT_SUCCESS;
5366 if (*++argv == NULL) {
5367 /* Don't care about wait results */
5368 /* Note 1: must wait until there are no more children */
5369 /* Note 2: must be interruptible */
5371 * $ sleep 3 & sleep 6 & wait
5376 * $ sleep 3 & sleep 6 & wait
5380 * ^C <-- after ~4 sec from keyboard
5383 sigaddset(&G.blocked_set, SIGCHLD);
5384 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5387 if (errno == ECHILD)
5389 /* Wait for SIGCHLD or any other signal of interest */
5390 /* sigtimedwait with infinite timeout: */
5391 sig = sigwaitinfo(&G.blocked_set, NULL);
5393 sig = check_and_run_traps(sig);
5394 if (sig && sig != SIGCHLD) { /* see note 2 */
5400 sigdelset(&G.blocked_set, SIGCHLD);
5401 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5405 /* This is probably buggy wrt interruptible-ness */
5407 pid_t pid = bb_strtou(*argv, NULL, 10);
5409 /* mimic bash message */
5410 bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
5411 return EXIT_FAILURE;
5413 if (waitpid(pid, &status, 0) == pid) {
5414 if (WIFSIGNALED(status))
5415 ret = 128 + WTERMSIG(status);
5416 else if (WIFEXITED(status))
5417 ret = WEXITSTATUS(status);
5421 bb_perror_msg("wait %s", *argv);
5430 #if ENABLE_HUSH_LOOPS
5431 static int builtin_break(char **argv)
5433 if (G.depth_of_loop == 0) {
5434 bb_error_msg("%s: only meaningful in a loop", argv[0]);
5435 return EXIT_SUCCESS; /* bash compat */
5437 G.flag_break_continue++; /* BC_BREAK = 1 */
5438 G.depth_break_continue = 1;
5440 G.depth_break_continue = bb_strtou(argv[1], NULL, 10);
5441 if (errno || !G.depth_break_continue || argv[2]) {
5442 bb_error_msg("%s: bad arguments", argv[0]);
5443 G.flag_break_continue = BC_BREAK;
5444 G.depth_break_continue = UINT_MAX;
5447 if (G.depth_of_loop < G.depth_break_continue)
5448 G.depth_break_continue = G.depth_of_loop;
5449 return EXIT_SUCCESS;
5452 static int builtin_continue(char **argv)
5454 G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
5455 return builtin_break(argv);