1 /* vi: set sw=4 ts=4: */
3 * A prototype Bourne shell grammar parser.
4 * Intended to follow the original Thompson and Ritchie
5 * "small and simple is beautiful" philosophy, which
6 * incidentally is a good match to today's BusyBox.
8 * Copyright (C) 2000,2001 Larry Doolittle <larry@doolittle.boa.org>
11 * The parser routines proper are all original material, first
12 * written Dec 2000 and Jan 2001 by Larry Doolittle. The
13 * execution engine, the builtins, and much of the underlying
14 * support has been adapted from busybox-0.49pre's lash, which is
15 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
16 * written by Erik Andersen <andersen@codepoet.org>. That, in turn,
17 * is based in part on ladsh.c, by Michael K. Johnson and Erik W.
18 * Troan, which they placed in the public domain. I don't know
19 * how much of the Johnson/Troan code has survived the repeated
23 * o_addchr() derived from similar w_addchar function in glibc-2.2.
24 * setup_redirect(), redirect_opt_num(), and big chunks of main()
25 * and many builtins derived from contributions by Erik Andersen.
26 * Miscellaneous bugfixes from Matt Kraai.
28 * There are two big (and related) architecture differences between
29 * this parser and the lash parser. One is that this version is
30 * actually designed from the ground up to understand nearly all
31 * of the Bourne grammar. The second, consequential change is that
32 * the parser and input reader have been turned inside out. Now,
33 * the parser is in control, and asks for input as needed. The old
34 * way had the input reader in control, and it asked for parsing to
35 * take place as needed. The new way makes it much easier to properly
36 * handle the recursion implicit in the various substitutions, especially
37 * across continuation lines.
39 * POSIX syntax not implemented:
41 * <(list) and >(list) Process Substitution
42 * Here Documents ( << word )
45 * Parameter Expansion for substring processing ${var#word} ${var%word}
47 * Bash stuff maybe optional enable:
48 * &> and >& redirection of stdout+stderr
50 * reserved words: [[ ]] function select
51 * substrings ${var:1:5}
54 * job handling woefully incomplete and buggy (improved --vda)
56 * port selected bugfixes from post-0.49 busybox lash - done?
57 * change { and } from special chars to reserved words
58 * builtins: return, trap, ulimit
59 * test magic exec with redirection only
60 * follow IFS rules more precisely, including update semantics
61 * figure out what to do with backslash-newline
62 * propagate syntax errors, die on resource errors?
63 * continuation lines, both explicit and implicit - done?
65 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
68 #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */
69 //TODO: pull in some .h and find out whether we have SINGLE_APPLET_MAIN?
70 //#include "applet_tables.h" doesn't work
72 /* #include <dmalloc.h> */
78 #ifdef WANT_TO_TEST_NOMMU
83 # define USE_FOR_NOMMU(...) __VA_ARGS__
84 # define USE_FOR_MMU(...)
87 #define HUSH_VER_STR "0.93"
89 #if defined SINGLE_APPLET_MAIN
90 /* STANDALONE does not make sense, and won't compile */
91 #undef CONFIG_FEATURE_SH_STANDALONE
92 #undef ENABLE_FEATURE_SH_STANDALONE
93 #undef USE_FEATURE_SH_STANDALONE
94 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
95 #define ENABLE_FEATURE_SH_STANDALONE 0
96 #define USE_FEATURE_SH_STANDALONE(...)
97 #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
100 #if !ENABLE_HUSH_INTERACTIVE
101 #undef ENABLE_FEATURE_EDITING
102 #define ENABLE_FEATURE_EDITING 0
103 #undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
104 #define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
107 /* Do we support ANY keywords? */
108 #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
109 #define HAS_KEYWORDS 1
110 #define IF_HAS_KEYWORDS(...) __VA_ARGS__
111 #define IF_HAS_NO_KEYWORDS(...)
113 #define HAS_KEYWORDS 0
114 #define IF_HAS_KEYWORDS(...)
115 #define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__
118 /* Keep unconditionally on for now */
121 #define ENABLE_HUSH_FUNCTIONS 0
124 /* If you comment out one of these below, it will be #defined later
125 * to perform debug printfs to stderr: */
126 #define debug_printf(...) do {} while (0)
127 /* Finer-grained debug switches */
128 #define debug_printf_parse(...) do {} while (0)
129 #define debug_print_tree(a, b) do {} while (0)
130 #define debug_printf_exec(...) do {} while (0)
131 #define debug_printf_env(...) do {} while (0)
132 #define debug_printf_jobs(...) do {} while (0)
133 #define debug_printf_expand(...) do {} while (0)
134 #define debug_printf_glob(...) do {} while (0)
135 #define debug_printf_list(...) do {} while (0)
136 #define debug_printf_subst(...) do {} while (0)
137 #define debug_printf_clean(...) do {} while (0)
140 #define debug_printf(...) fprintf(stderr, __VA_ARGS__)
143 #ifndef debug_printf_parse
144 #define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__)
147 #ifndef debug_printf_exec
148 #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__)
151 #ifndef debug_printf_env
152 #define debug_printf_env(...) fprintf(stderr, __VA_ARGS__)
155 #ifndef debug_printf_jobs
156 #define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__)
162 #ifndef debug_printf_expand
163 #define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__)
164 #define DEBUG_EXPAND 1
166 #define DEBUG_EXPAND 0
169 #ifndef debug_printf_glob
170 #define debug_printf_glob(...) fprintf(stderr, __VA_ARGS__)
176 #ifndef debug_printf_list
177 #define debug_printf_list(...) fprintf(stderr, __VA_ARGS__)
180 #ifndef debug_printf_subst
181 #define debug_printf_subst(...) fprintf(stderr, __VA_ARGS__)
184 #ifndef debug_printf_clean
185 /* broken, of course, but OK for testing */
186 static const char *indenter(int i)
188 static const char blanks[] ALIGN1 =
190 return &blanks[sizeof(blanks) - i - 1];
192 #define debug_printf_clean(...) fprintf(stderr, __VA_ARGS__)
193 #define DEBUG_CLEAN 1
197 static void debug_print_strings(const char *prefix, char **vv)
199 fprintf(stderr, "%s:\n", prefix);
201 fprintf(stderr, " '%s'\n", *vv++);
204 #define debug_print_strings(prefix, vv) ((void)0)
208 * Leak hunting. Use hush_leaktool.sh for post-processing.
210 #ifdef FOR_HUSH_LEAKTOOL
211 static void *xxmalloc(int lineno, size_t size)
213 void *ptr = xmalloc((size + 0xff) & ~0xff);
214 fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
217 static void *xxrealloc(int lineno, void *ptr, size_t size)
219 ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
220 fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
223 static char *xxstrdup(int lineno, const char *str)
225 char *ptr = xstrdup(str);
226 fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
229 static void xxfree(void *ptr)
231 fdprintf(2, "free %p\n", ptr);
234 #define xmalloc(s) xxmalloc(__LINE__, s)
235 #define xrealloc(p, s) xxrealloc(__LINE__, p, s)
236 #define xstrdup(s) xxstrdup(__LINE__, s)
237 #define free(p) xxfree(p)
241 #define ERR_PTR ((void*)(long)1)
243 static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="HUSH_VER_STR;
245 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
247 #define SPECIAL_VAR_SYMBOL 3
249 typedef enum redir_type {
251 REDIRECT_OVERWRITE = 2,
257 /* The descrip member of this structure is only used to make
258 * debugging output pretty */
259 static const struct {
261 signed char default_fd;
265 { O_RDONLY, 0, "<" },
266 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
267 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
268 { O_RDONLY, -1, "<<" },
272 typedef enum pipe_style {
279 typedef enum reserved_style {
288 #if ENABLE_HUSH_LOOPS
295 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
300 /* two pseudo-keywords support contrived "case" syntax: */
301 RES_MATCH , /* "word)" */
302 RES_CASEI , /* "this command is inside CASE" */
309 typedef struct o_string {
311 int length; /* position where data is appended */
313 /* Protect newly added chars against globbing
314 * (by prepending \ to *, ?, [, \) */
318 smallint has_empty_slot;
319 smallint o_assignment; /* 0:maybe, 1:yes, 2:no */
322 MAYBE_ASSIGNMENT = 0,
323 DEFINITELY_ASSIGNMENT = 1,
325 WORD_IS_KEYWORD = 3, /* not assigment, but next word may be: "if v=xyz cmd;" */
327 /* Used for initialization: o_string foo = NULL_O_STRING; */
328 #define NULL_O_STRING { NULL }
330 /* I can almost use ordinary FILE*. Is open_memstream() universally
331 * available? Where is it documented? */
332 typedef struct in_str {
334 /* eof_flag=1: last char in ->p is really an EOF */
335 char eof_flag; /* meaningless if ->p == NULL */
337 #if ENABLE_HUSH_INTERACTIVE
339 smallint promptmode; /* 0: PS1, 1: PS2 */
342 int (*get) (struct in_str *);
343 int (*peek) (struct in_str *);
345 #define i_getch(input) ((input)->get(input))
346 #define i_peek(input) ((input)->peek(input))
348 struct redir_struct {
349 struct redir_struct *next;
350 char *rd_filename; /* filename */
351 int fd; /* file descriptor being redirected */
352 int dup; /* -1, or file descriptor being duplicated */
353 smallint /*enum redir_type*/ rd_type;
357 pid_t pid; /* 0 if exited */
358 int assignment_cnt; /* how many argv[i] are assignments? */
359 smallint is_stopped; /* is the command currently running? */
360 smallint grp_type; /* GRP_xxx */
361 struct pipe *group; /* if non-NULL, this "command" is { list },
362 * ( list ), or a compound statement */
364 char *group_as_string;
366 char **argv; /* command name and arguments */
367 struct redir_struct *redirects; /* I/O redirections */
369 /* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
370 * and on execution these are substituted with their values.
371 * Substitution can make _several_ words out of one argv[n]!
372 * Example: argv[0]=='.^C*^C.' here: echo .$*.
373 * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
376 #define GRP_SUBSHELL 1
377 #if ENABLE_HUSH_FUNCTIONS
378 #define GRP_FUNCTION 2
383 int num_cmds; /* total number of commands in job */
384 int alive_cmds; /* number of commands running (not exited) */
385 int stopped_cmds; /* number of commands alive, but stopped */
387 int jobid; /* job number */
388 pid_t pgrp; /* process group ID for the job */
389 char *cmdtext; /* name of job */
391 struct command *cmds; /* array of commands in pipe */
392 smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
393 IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */
394 IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */
397 /* This holds pointers to the various results of parsing */
398 struct parse_context {
399 /* linked list of pipes */
400 struct pipe *list_head;
401 /* last pipe (being constructed right now) */
403 /* last command in pipe (being constructed right now) */
404 struct command *command;
405 /* last redirect in command->redirects list */
406 struct redir_struct *pending_redirect;
412 smallint ctx_inverted; /* "! cmd | cmd" */
414 smallint ctx_dsemicolon; /* ";;" seen */
416 /* bitmask of FLAG_xxx, for figuring out valid reserved words */
418 /* group we are enclosed in:
419 * example: "if pipe1; pipe2; then pipe3; fi"
420 * when we see "if" or "then", we malloc and copy current context,
421 * and make ->stack point to it. then we parse pipeN.
422 * when closing "then" / fi" / whatever is found,
423 * we move list_head into ->stack->command->group,
424 * copy ->stack into current context, and delete ->stack.
425 * (parsing of { list } and ( list ) doesn't use this method)
427 struct parse_context *stack;
431 /* On program start, environ points to initial environment.
432 * putenv adds new pointers into it, unsetenv removes them.
433 * Neither of these (de)allocates the strings.
434 * setenv allocates new strings in malloc space and does putenv,
435 * and thus setenv is unusable (leaky) for shell's purposes */
436 #define setenv(...) setenv_is_leaky_dont_use()
438 struct variable *next;
439 char *varstr; /* points to "name=" portion */
440 int max_len; /* if > 0, name is part of initial env; else name is malloced */
441 smallint flg_export; /* putenv should be done on this var */
442 smallint flg_read_only;
451 /* "Globals" within this file */
452 /* Sorted roughly by size (smaller offsets == smaller code) */
454 #if ENABLE_HUSH_INTERACTIVE
455 /* 'interactive_fd' is a fd# open to ctty, if we have one
456 * _AND_ if we decided to act interactively */
460 #define G_interactive_fd (G.interactive_fd)
462 #define G_interactive_fd 0
464 #if ENABLE_FEATURE_EDITING
465 line_input_t *line_input_state;
471 pid_t saved_tty_pgrp;
473 struct pipe *job_list;
474 struct pipe *toplevel_list;
475 //// smallint ctrl_z_flag;
477 smallint flag_SIGINT;
478 #if ENABLE_HUSH_LOOPS
479 smallint flag_break_continue;
482 /* These four support $?, $#, and $1 */
483 smalluint last_return_code;
484 /* is global_argv and global_argv[1..n] malloced? (note: not [0]) */
485 smalluint global_args_malloced;
486 /* how many non-NULL argv's we have. NB: $# + 1 */
489 #if ENABLE_HUSH_LOOPS
490 unsigned depth_break_continue;
491 unsigned depth_of_loop;
495 struct variable *top_var; /* = &G.shell_ver (set in main()) */
496 struct variable shell_ver;
497 /* Signal and trap handling */
498 // unsigned count_SIGCHLD;
499 // unsigned handled_SIGCHLD;
500 /* which signals have non-DFL handler (even with no traps set)? */
501 unsigned non_DFL_mask;
502 char **traps; /* char *traps[NSIG] */
503 sigset_t blocked_set;
504 sigset_t inherited_set;
505 char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
506 #if ENABLE_FEATURE_SH_STANDALONE
507 struct nofork_save_area nofork_save;
510 sigjmp_buf toplevel_jb;
513 #define G (*ptr_to_globals)
514 /* Not #defining name to G.name - this quickly gets unwieldy
515 * (too many defines). Also, I actually prefer to see when a variable
516 * is global, thus "G." prefix is a useful hint */
517 #define INIT_G() do { \
518 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
522 /* Function prototypes for builtins */
523 static int builtin_cd(char **argv);
524 static int builtin_echo(char **argv);
525 static int builtin_eval(char **argv);
526 static int builtin_exec(char **argv);
527 static int builtin_exit(char **argv);
528 static int builtin_export(char **argv);
530 static int builtin_fg_bg(char **argv);
531 static int builtin_jobs(char **argv);
534 static int builtin_help(char **argv);
536 static int builtin_pwd(char **argv);
537 static int builtin_read(char **argv);
538 static int builtin_test(char **argv);
539 static int builtin_trap(char **argv);
540 static int builtin_true(char **argv);
541 static int builtin_set(char **argv);
542 static int builtin_shift(char **argv);
543 static int builtin_source(char **argv);
544 static int builtin_umask(char **argv);
545 static int builtin_unset(char **argv);
546 static int builtin_wait(char **argv);
547 #if ENABLE_HUSH_LOOPS
548 static int builtin_break(char **argv);
549 static int builtin_continue(char **argv);
552 /* Table of built-in functions. They can be forked or not, depending on
553 * context: within pipes, they fork. As simple commands, they do not.
554 * When used in non-forking context, they can change global variables
555 * in the parent shell process. If forked, of course they cannot.
556 * For example, 'unset foo | whatever' will parse and run, but foo will
557 * still be set at the end. */
558 struct built_in_command {
560 int (*function)(char **argv);
563 #define BLTIN(cmd, func, help) { cmd, func, help }
565 #define BLTIN(cmd, func, help) { cmd, func }
569 /* For now, echo and test are unconditionally enabled.
570 * Maybe make it configurable? */
571 static const struct built_in_command bltins[] = {
572 BLTIN("." , builtin_source , "Run commands in a file"),
573 BLTIN(":" , builtin_true , "No-op"),
574 BLTIN("[" , builtin_test , "Test condition"),
576 BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
578 #if ENABLE_HUSH_LOOPS
579 BLTIN("break" , builtin_break , "Exit from a loop"),
581 BLTIN("cd" , builtin_cd , "Change directory"),
582 #if ENABLE_HUSH_LOOPS
583 BLTIN("continue", builtin_continue, "Start new loop iteration"),
585 BLTIN("echo" , builtin_echo , "Write to stdout"),
586 BLTIN("eval" , builtin_eval , "Construct and run shell command"),
587 BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
588 BLTIN("exit" , builtin_exit , "Exit"),
589 BLTIN("export" , builtin_export , "Set environment variable"),
591 BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
594 BLTIN("help" , builtin_help , "List shell built-in commands"),
597 BLTIN("jobs" , builtin_jobs , "List active jobs"),
599 BLTIN("pwd" , builtin_pwd , "Print current directory"),
600 BLTIN("read" , builtin_read , "Input environment variable"),
601 // BLTIN("return" , builtin_return , "Return from a function"),
602 BLTIN("set" , builtin_set , "Set/unset shell local variables"),
603 BLTIN("shift" , builtin_shift , "Shift positional parameters"),
604 BLTIN("test" , builtin_test , "Test condition"),
605 BLTIN("trap" , builtin_trap , "Trap signals"),
606 // BLTIN("ulimit" , builtin_return , "Control resource limits"),
607 BLTIN("umask" , builtin_umask , "Set file creation mask"),
608 BLTIN("unset" , builtin_unset , "Unset environment variable"),
609 BLTIN("wait" , builtin_wait , "Wait for process"),
613 static void maybe_die(const char *notice, const char *msg)
615 /* Was using fancy stuff:
616 * (G_interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...)
617 * but it SEGVs. ?! Oh well... explicit temp ptr works around that */
618 void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die;
619 #if ENABLE_HUSH_INTERACTIVE
620 if (G_interactive_fd)
623 fp(msg ? "%s: %s" : notice, notice, msg);
626 #define syntax(msg) maybe_die("syntax error", msg);
628 /* Debug -- trick gcc to expand __LINE__ and convert to string */
629 #define __syntax(msg, line) maybe_die("syntax error hush.c:" # line, msg)
630 #define _syntax(msg, line) __syntax(msg, line)
631 #define syntax(msg) _syntax(msg, __LINE__)
635 static int glob_needed(const char *s)
640 if (*s == '*' || *s == '[' || *s == '?')
647 static int is_assignment(const char *s)
649 if (!s || !(isalpha(*s) || *s == '_'))
652 while (isalnum(*s) || *s == '_')
657 /* Replace each \x with x in place, return ptr past NUL. */
658 static char *unbackslash(char *src)
664 if ((*dst++ = *src++) == '\0')
670 static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
691 v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
692 v[count1 + count2] = NULL;
695 v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
699 static char **add_string_to_strings(char **strings, char *add)
704 return add_strings_to_strings(strings, v, /*dup:*/ 0);
707 static void putenv_all(char **strings)
712 debug_printf_env("putenv '%s'\n", *strings);
717 static char **putenv_all_and_save_old(char **strings)
727 eq = strchr(*strings, '=');
730 v = getenv(*strings);
733 /* v points to VAL in VAR=VAL, go back to VAR */
734 v -= (eq - *strings) + 1;
735 old = add_string_to_strings(old, v);
744 static void free_strings_and_unsetenv(char **strings, int unset)
754 debug_printf_env("unsetenv '%s'\n", *v);
762 static void free_strings(char **strings)
764 free_strings_and_unsetenv(strings, 0);
768 /* Basic theory of signal handling in shell
769 * ========================================
770 * This does not describe what hush does, rather, it is current understanding
771 * what it _should_ do. If it doesn't, it's a bug.
772 * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
774 * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
775 * is finished or backgrounded. It is the same in interactive and
776 * non-interactive shells, and is the same regardless of whether
777 * a user trap handler is installed or a shell special one is in effect.
778 * ^C or ^Z from keyboard seem to execute "at once" because it usually
779 * backgrounds (i.e. stops) or kills all members of currently running
782 * Wait builtin in interruptible by signals for which user trap is set
783 * or by SIGINT in interactive shell.
785 * Trap handlers will execute even within trap handlers. (right?)
787 * User trap handlers are forgotten when subshell ("(cmd)") is entered. [TODO]
789 * If job control is off, backgrounded commands ("cmd &")
790 * have SIGINT, SIGQUIT set to SIG_IGN.
792 * Commands run in command substitution ("`cmd`")
793 * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
795 * Ordinary commands have signals set to SIG_IGN/DFL set as inherited
796 * by the shell from its parent.
798 * Siganls which differ from SIG_DFL action
799 * (note: child (i.e., [v]forked) shell is not an interactive shell):
802 * SIGTERM (interactive): ignore
803 * SIGHUP (interactive):
804 * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
805 * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
806 * (note that ^Z is handled not by trapping SIGTSTP, but by seeing
807 * that all pipe members are stopped) (right?)
808 * SIGINT (interactive): wait for last pipe, ignore the rest
809 * of the command line, show prompt. NB: ^C does not send SIGINT
810 * to interactive shell while shell is waiting for a pipe,
811 * since shell is bg'ed (is not in foreground process group).
812 * (check/expand this)
813 * Example 1: this waits 5 sec, but does not execute ls:
814 * "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
815 * Example 2: this does not wait and does not execute ls:
816 * "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
817 * Example 3: this does not wait 5 sec, but executes ls:
818 * "sleep 5; ls -l" + press ^C
820 * (What happens to signals which are IGN on shell start?)
821 * (What happens with signal mask on shell start?)
823 * Implementation in hush
824 * ======================
825 * We use in-kernel pending signal mask to determine which signals were sent.
826 * We block all signals which we don't want to take action immediately,
827 * i.e. we block all signals which need to have special handling as described
828 * above, and all signals which have traps set.
829 * After each pipe execution, we extract any pending signals via sigtimedwait()
832 * unsigned non_DFL_mask: a mask of such "special" signals
833 * sigset_t blocked_set: current blocked signal set
836 * clear bit in blocked_set unless it is also in non_DFL_mask
837 * "trap 'cmd' SIGxxx":
838 * set bit in blocked_set (even if 'cmd' is '')
839 * after [v]fork, if we plan to be a shell:
840 * nothing for {} child shell (say, "true | { true; true; } | true")
841 * unset all traps if () shell. [TODO]
842 * after [v]fork, if we plan to exec:
843 * POSIX says pending signal mask is cleared in child - no need to clear it.
844 * Restore blocked signal set to one inherited by shell just prior to exec.
846 * Note: as a result, we do not use signal handlers much. The only uses
847 * are to count SIGCHLDs [disabled - bug somewhere, + bloat]
848 * and to restore tty pgrp on signal-induced exit.
850 * TODO: check/fix wait builtin to be interruptible.
853 //static void SIGCHLD_handler(int sig UNUSED_PARAM)
855 // G.count_SIGCHLD++;
858 /* called once at shell init */
859 static void init_signal_mask(void)
862 unsigned mask = (1 << SIGQUIT);
863 if (G_interactive_fd) {
869 | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
874 G.non_DFL_mask = mask;
876 sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
880 sigaddset(&G.blocked_set, sig);
884 sigdelset(&G.blocked_set, SIGCHLD);
885 sigprocmask(SIG_SETMASK, &G.blocked_set, &G.inherited_set);
888 static int check_and_run_traps(int sig)
890 static const struct timespec zero_timespec = { 0, 0 };
891 smalluint save_rcode;
897 sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec);
902 if (G.traps && G.traps[sig]) {
903 if (G.traps[sig][0]) {
904 /* We have user-defined handler */
905 char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL };
906 save_rcode = G.last_return_code;
909 G.last_return_code = save_rcode;
910 } /* else: "" trap, ignoring signal */
913 /* not a trap: special action */
916 // G.count_SIGCHLD++;
925 default: /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
934 /* Restores tty foreground process group, and exits.
935 * May be called as signal handler for fatal signal
936 * (will faithfully resend signal to itself, producing correct exit state)
937 * or called directly with -EXITCODE.
938 * We also call it if xfunc is exiting. */
939 static void sigexit(int sig) NORETURN;
940 static void sigexit(int sig)
942 /* Disable all signals: job control, SIGPIPE, etc. */
943 sigprocmask_allsigs(SIG_BLOCK);
945 /* Careful: we can end up here after [v]fork. Do not restore
946 * tty pgrp then, only top-level shell process does that */
947 if (G_interactive_fd && getpid() == G.root_pid)
948 tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
950 /* Not a signal, just exit */
954 kill_myself_with_sig(sig); /* does not return */
958 static void maybe_set_sighandler(int sig)
960 void (*handler)(int);
961 /* non_DFL_mask'ed signals are, well, masked,
962 * no need to set handler for them.
964 if (!((G.non_DFL_mask >> sig) & 1)) {
965 handler = signal(sig, sigexit);
966 if (handler == SIG_IGN) /* oops... restore back to IGN! */
967 signal(sig, handler);
970 /* Used only to set handler to restore pgrp on exit */
971 static void set_fatal_signals_to_sigexit(void)
974 maybe_set_sighandler(SIGILL );
975 maybe_set_sighandler(SIGFPE );
976 maybe_set_sighandler(SIGBUS );
977 maybe_set_sighandler(SIGSEGV);
978 maybe_set_sighandler(SIGTRAP);
979 } /* else: hush is perfect. what SEGV? */
981 maybe_set_sighandler(SIGABRT);
983 /* bash 3.2 seems to handle these just like 'fatal' ones */
984 maybe_set_sighandler(SIGPIPE);
985 maybe_set_sighandler(SIGALRM);
986 maybe_set_sighandler(SIGHUP );
988 /* if we aren't interactive... but in this case
989 * we never want to restore pgrp on exit, and this fn is not called */
990 /*maybe_set_sighandler(SIGTERM);*/
991 /*maybe_set_sighandler(SIGINT );*/
996 #define set_fatal_signals_to_sigexit(handler) ((void)0)
1000 /* Restores tty foreground process group, and exits. */
1001 static void hush_exit(int exitcode) NORETURN;
1002 static void hush_exit(int exitcode)
1004 if (G.traps && G.traps[0] && G.traps[0][0]) {
1005 char *argv[] = { NULL, xstrdup(G.traps[0]), NULL };
1011 fflush(NULL); /* flush all streams */
1012 sigexit(- (exitcode & 0xff));
1019 static const char *set_cwd(void)
1021 /* xrealloc_getcwd_or_warn(arg) calls free(arg),
1022 * we must not try to free(bb_msg_unknown) */
1023 if (G.cwd == bb_msg_unknown)
1025 G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
1027 G.cwd = bb_msg_unknown;
1032 /* Get/check local shell variables */
1033 static struct variable *get_local_var(const char *name)
1035 struct variable *cur;
1041 for (cur = G.top_var; cur; cur = cur->next) {
1042 if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
1048 static const char *get_local_var_value(const char *src)
1050 struct variable *var = get_local_var(src);
1052 return strchr(var->varstr, '=') + 1;
1056 /* str holds "NAME=VAL" and is expected to be malloced.
1057 * We take ownership of it.
1058 * flg_export is used by:
1061 * -1: if NAME is set, leave export status alone
1062 * if NAME is not set, do not export
1064 static int set_local_var(char *str, int flg_export)
1066 struct variable *cur;
1070 value = strchr(str, '=');
1071 if (!value) { /* not expected to ever happen? */
1076 name_len = value - str + 1; /* including '=' */
1077 cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
1079 if (strncmp(cur->varstr, str, name_len) != 0) {
1081 /* Bail out. Note that now cur points
1082 * to last var in linked list */
1088 /* We found an existing var with this name */
1090 if (cur->flg_read_only) {
1091 bb_error_msg("%s: readonly variable", str);
1095 debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
1096 unsetenv(str); /* just in case */
1098 if (strcmp(cur->varstr, str) == 0) {
1103 if (cur->max_len >= strlen(str)) {
1104 /* This one is from startup env, reuse space */
1105 strcpy(cur->varstr, str);
1108 /* max_len == 0 signifies "malloced" var, which we can
1109 * (and has to) free */
1113 goto set_str_and_exp;
1116 /* Not found - create next variable struct */
1117 cur->next = xzalloc(sizeof(*cur));
1123 if (flg_export == 1)
1124 cur->flg_export = 1;
1125 if (cur->flg_export) {
1126 debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
1127 return putenv(cur->varstr);
1132 static int unset_local_var(const char *name)
1134 struct variable *cur;
1135 struct variable *prev = prev; /* for gcc */
1139 return EXIT_SUCCESS;
1140 name_len = strlen(name);
1143 if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
1144 if (cur->flg_read_only) {
1145 bb_error_msg("%s: readonly variable", name);
1146 return EXIT_FAILURE;
1148 /* prev is ok to use here because 1st variable, HUSH_VERSION,
1149 * is ro, and we cannot reach this code on the 1st pass */
1150 prev->next = cur->next;
1151 debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
1152 bb_unsetenv(cur->varstr);
1156 return EXIT_SUCCESS;
1161 return EXIT_SUCCESS;
1164 #if ENABLE_SH_MATH_SUPPORT
1165 #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c)))
1166 #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c)))
1167 static char *endofname(const char *name)
1175 if (!is_in_name(*p))
1181 static void arith_set_local_var(const char *name, const char *val, int flags)
1183 /* arith code doesnt malloc space, so do it for it */
1184 char *var = xasprintf("%s=%s", name, val);
1185 set_local_var(var, flags);
1193 static int static_get(struct in_str *i)
1202 static int static_peek(struct in_str *i)
1207 #if ENABLE_HUSH_INTERACTIVE
1209 static void cmdedit_set_initial_prompt(void)
1211 if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1212 G.PS1 = getenv("PS1");
1219 static const char* setup_prompt_string(int promptmode)
1221 const char *prompt_str;
1222 debug_printf("setup_prompt_string %d ", promptmode);
1223 if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
1224 /* Set up the prompt */
1225 if (promptmode == 0) { /* PS1 */
1227 G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#');
1232 prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
1233 debug_printf("result '%s'\n", prompt_str);
1237 static void get_user_input(struct in_str *i)
1240 const char *prompt_str;
1242 prompt_str = setup_prompt_string(i->promptmode);
1243 #if ENABLE_FEATURE_EDITING
1244 /* Enable command line editing only while a command line
1245 * is actually being read */
1248 /* buglet: SIGINT will not make new prompt to appear _at once_,
1249 * only after <Enter>. (^C will work) */
1250 r = read_line_input(prompt_str, G.user_input_buf, BUFSIZ-1, G.line_input_state);
1251 /* catch *SIGINT* etc (^C is handled by read_line_input) */
1252 check_and_run_traps(0);
1253 } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */
1254 i->eof_flag = (r < 0);
1255 if (i->eof_flag) { /* EOF/error detected */
1256 G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
1257 G.user_input_buf[1] = '\0';
1262 fputs(prompt_str, stdout);
1264 G.user_input_buf[0] = r = fgetc(i->file);
1265 /*G.user_input_buf[1] = '\0'; - already is and never changed */
1266 //do we need check_and_run_traps(0)? (maybe only if stdin)
1267 } while (G.flag_SIGINT);
1268 i->eof_flag = (r == EOF);
1270 i->p = G.user_input_buf;
1273 #endif /* INTERACTIVE */
1275 /* This is the magic location that prints prompts
1276 * and gets data back from the user */
1277 static int file_get(struct in_str *i)
1281 /* If there is data waiting, eat it up */
1282 if (i->p && *i->p) {
1283 #if ENABLE_HUSH_INTERACTIVE
1287 if (i->eof_flag && !*i->p)
1290 /* need to double check i->file because we might be doing something
1291 * more complicated by now, like sourcing or substituting. */
1292 #if ENABLE_HUSH_INTERACTIVE
1293 if (G_interactive_fd && i->promptme && i->file == stdin) {
1296 } while (!*i->p); /* need non-empty line */
1297 i->promptmode = 1; /* PS2 */
1302 ch = fgetc(i->file);
1304 debug_printf("file_get: got a '%c' %d\n", ch, ch);
1305 #if ENABLE_HUSH_INTERACTIVE
1312 /* All the callers guarantee this routine will never be
1313 * used right after a newline, so prompting is not needed.
1315 static int file_peek(struct in_str *i)
1318 if (i->p && *i->p) {
1319 if (i->eof_flag && !i->p[1])
1323 ch = fgetc(i->file);
1324 i->eof_flag = (ch == EOF);
1325 i->peek_buf[0] = ch;
1326 i->peek_buf[1] = '\0';
1328 debug_printf("file_peek: got a '%c' %d\n", *i->p, *i->p);
1332 static void setup_file_in_str(struct in_str *i, FILE *f)
1334 i->peek = file_peek;
1336 #if ENABLE_HUSH_INTERACTIVE
1338 i->promptmode = 0; /* PS1 */
1344 static void setup_string_in_str(struct in_str *i, const char *s)
1346 i->peek = static_peek;
1347 i->get = static_get;
1348 #if ENABLE_HUSH_INTERACTIVE
1350 i->promptmode = 0; /* PS1 */
1360 #define B_CHUNK (32 * sizeof(char*))
1362 static void o_reset(o_string *o)
1370 static void o_free(o_string *o)
1373 memset(o, 0, sizeof(*o));
1376 static ALWAYS_INLINE void o_free_unsafe(o_string *o)
1381 static void o_grow_by(o_string *o, int len)
1383 if (o->length + len > o->maxlen) {
1384 o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
1385 o->data = xrealloc(o->data, 1 + o->maxlen);
1389 static void o_addchr(o_string *o, int ch)
1391 debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
1393 o->data[o->length] = ch;
1395 o->data[o->length] = '\0';
1398 static void o_addblock(o_string *o, const char *str, int len)
1401 memcpy(&o->data[o->length], str, len);
1403 o->data[o->length] = '\0';
1407 static void o_addstr(o_string *o, const char *str)
1409 o_addblock(o, str, strlen(str));
1413 static void o_addstr_with_NUL(o_string *o, const char *str)
1415 o_addblock(o, str, strlen(str) + 1);
1418 static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
1423 && (*str != '*' && *str != '?' && *str != '[')
1431 /* My analysis of quoting semantics tells me that state information
1432 * is associated with a destination, not a source.
1434 static void o_addqchr(o_string *o, int ch)
1437 char *found = strchr("*?[\\", ch);
1442 o->data[o->length] = '\\';
1445 o->data[o->length] = ch;
1447 o->data[o->length] = '\0';
1450 static void o_addQchr(o_string *o, int ch)
1453 if (o->o_escape && strchr("*?[\\", ch)) {
1455 o->data[o->length] = '\\';
1459 o->data[o->length] = ch;
1461 o->data[o->length] = '\0';
1464 static void o_addQstr(o_string *o, const char *str, int len)
1467 o_addblock(o, str, len);
1473 int ordinary_cnt = strcspn(str, "*?[\\");
1474 if (ordinary_cnt > len) /* paranoia */
1476 o_addblock(o, str, ordinary_cnt);
1477 if (ordinary_cnt == len)
1479 str += ordinary_cnt;
1480 len -= ordinary_cnt + 1; /* we are processing + 1 char below */
1484 if (ch) { /* it is necessarily one of "*?[\\" */
1486 o->data[o->length] = '\\';
1490 o->data[o->length] = ch;
1492 o->data[o->length] = '\0';
1496 /* A special kind of o_string for $VAR and `cmd` expansion.
1497 * It contains char* list[] at the beginning, which is grown in 16 element
1498 * increments. Actual string data starts at the next multiple of 16 * (char*).
1499 * list[i] contains an INDEX (int!) into this string data.
1500 * It means that if list[] needs to grow, data needs to be moved higher up
1501 * but list[i]'s need not be modified.
1502 * NB: remembering how many list[i]'s you have there is crucial.
1503 * o_finalize_list() operation post-processes this structure - calculates
1504 * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
1506 #if DEBUG_EXPAND || DEBUG_GLOB
1507 static void debug_print_list(const char *prefix, o_string *o, int n)
1509 char **list = (char**)o->data;
1510 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1512 fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n",
1513 prefix, list, n, string_start, o->length, o->maxlen);
1515 fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i],
1516 o->data + (int)list[i] + string_start,
1517 o->data + (int)list[i] + string_start);
1521 const char *p = o->data + (int)list[n - 1] + string_start;
1522 fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
1526 #define debug_print_list(prefix, o, n) ((void)0)
1529 /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
1530 * in list[n] so that it points past last stored byte so far.
1531 * It returns n+1. */
1532 static int o_save_ptr_helper(o_string *o, int n)
1534 char **list = (char**)o->data;
1538 if (!o->has_empty_slot) {
1539 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1540 string_len = o->length - string_start;
1541 if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
1542 debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
1543 /* list[n] points to string_start, make space for 16 more pointers */
1544 o->maxlen += 0x10 * sizeof(list[0]);
1545 o->data = xrealloc(o->data, o->maxlen + 1);
1546 list = (char**)o->data;
1547 memmove(list + n + 0x10, list + n, string_len);
1548 o->length += 0x10 * sizeof(list[0]);
1550 debug_printf_list("list[%d]=%d string_start=%d\n",
1551 n, string_len, string_start);
1554 /* We have empty slot at list[n], reuse without growth */
1555 string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
1556 string_len = o->length - string_start;
1557 debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n",
1558 n, string_len, string_start);
1559 o->has_empty_slot = 0;
1561 list[n] = (char*)(ptrdiff_t)string_len;
1565 /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
1566 static int o_get_last_ptr(o_string *o, int n)
1568 char **list = (char**)o->data;
1569 int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1571 return ((int)(ptrdiff_t)list[n-1]) + string_start;
1574 /* o_glob performs globbing on last list[], saving each result
1575 * as a new list[]. */
1576 static int o_glob(o_string *o, int n)
1582 debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
1584 return o_save_ptr_helper(o, n);
1585 pattern = o->data + o_get_last_ptr(o, n);
1586 debug_printf_glob("glob pattern '%s'\n", pattern);
1587 if (!glob_needed(pattern)) {
1589 o->length = unbackslash(pattern) - o->data;
1590 debug_printf_glob("glob pattern '%s' is literal\n", pattern);
1591 return o_save_ptr_helper(o, n);
1594 memset(&globdata, 0, sizeof(globdata));
1595 gr = glob(pattern, 0, NULL, &globdata);
1596 debug_printf_glob("glob('%s'):%d\n", pattern, gr);
1597 if (gr == GLOB_NOSPACE)
1598 bb_error_msg_and_die("out of memory during glob");
1599 if (gr == GLOB_NOMATCH) {
1600 globfree(&globdata);
1603 if (gr != 0) { /* GLOB_ABORTED ? */
1604 //TODO: testcase for bad glob pattern behavior
1605 bb_error_msg("glob(3) error %d on '%s'", gr, pattern);
1607 if (globdata.gl_pathv && globdata.gl_pathv[0]) {
1608 char **argv = globdata.gl_pathv;
1609 o->length = pattern - o->data; /* "forget" pattern */
1611 o_addstr_with_NUL(o, *argv);
1612 n = o_save_ptr_helper(o, n);
1618 globfree(&globdata);
1620 debug_print_list("o_glob returning", o, n);
1624 /* If o->o_glob == 1, glob the string so far remembered.
1625 * Otherwise, just finish current list[] and start new */
1626 static int o_save_ptr(o_string *o, int n)
1628 if (o->o_glob) { /* if globbing is requested */
1629 /* If o->has_empty_slot, list[n] was already globbed
1630 * (if it was requested back then when it was filled)
1631 * so don't do that again! */
1632 if (!o->has_empty_slot)
1633 return o_glob(o, n); /* o_save_ptr_helper is inside */
1635 return o_save_ptr_helper(o, n);
1638 /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
1639 static char **o_finalize_list(o_string *o, int n)
1644 n = o_save_ptr(o, n); /* force growth for list[n] if necessary */
1646 debug_print_list("finalized", o, n);
1647 debug_printf_expand("finalized n:%d\n", n);
1648 list = (char**)o->data;
1649 string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
1653 list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start;
1659 /* Expansion can recurse */
1660 #if ENABLE_HUSH_TICK
1661 static int process_command_subs(o_string *dest, const char *s);
1663 static char *expand_string_to_string(const char *str);
1665 #define parse_stream_dquoted(ctx, dest, input, dquote_end) \
1666 parse_stream_dquoted(dest, input, dquote_end)
1668 static int parse_stream_dquoted(struct parse_context *ctx,
1670 struct in_str *input,
1673 /* expand_strvec_to_strvec() takes a list of strings, expands
1674 * all variable references within and returns a pointer to
1675 * a list of expanded strings, possibly with larger number
1676 * of strings. (Think VAR="a b"; echo $VAR).
1677 * This new list is allocated as a single malloc block.
1678 * NULL-terminated list of char* pointers is at the beginning of it,
1679 * followed by strings themself.
1680 * Caller can deallocate entire list by single free(list). */
1682 /* Store given string, finalizing the word and starting new one whenever
1683 * we encounter IFS char(s). This is used for expanding variable values.
1684 * End-of-string does NOT finalize word: think about 'echo -$VAR-' */
1685 static int expand_on_ifs(o_string *output, int n, const char *str)
1688 int word_len = strcspn(str, G.ifs);
1690 if (output->o_escape || !output->o_glob)
1691 o_addQstr(output, str, word_len);
1692 else /* protect backslashes against globbing up :) */
1693 o_addblock_duplicate_backslash(output, str, word_len);
1696 if (!*str) /* EOL - do not finalize word */
1698 o_addchr(output, '\0');
1699 debug_print_list("expand_on_ifs", output, n);
1700 n = o_save_ptr(output, n);
1701 str += strspn(str, G.ifs); /* skip ifs chars */
1703 debug_print_list("expand_on_ifs[1]", output, n);
1707 /* Expand all variable references in given string, adding words to list[]
1708 * at n, n+1,... positions. Return updated n (so that list[n] is next one
1709 * to be filled). This routine is extremely tricky: has to deal with
1710 * variables/parameters with whitespace, $* and $@, and constructs like
1711 * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
1712 static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
1714 /* or_mask is either 0 (normal case) or 0x80
1715 * (expansion of right-hand side of assignment == 1-element expand.
1716 * It will also do no globbing, and thus we must not backslash-quote!) */
1718 char first_ch, ored_ch;
1725 debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
1726 debug_print_list("expand_vars_to_list", output, n);
1727 n = o_save_ptr(output, n);
1728 debug_print_list("expand_vars_to_list[0]", output, n);
1730 while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
1731 #if ENABLE_HUSH_TICK
1732 o_string subst_result = NULL_O_STRING;
1734 #if ENABLE_SH_MATH_SUPPORT
1735 char arith_buf[sizeof(arith_t)*3 + 2];
1737 o_addblock(output, arg, p - arg);
1738 debug_print_list("expand_vars_to_list[1]", output, n);
1740 p = strchr(p, SPECIAL_VAR_SYMBOL);
1742 first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
1743 /* "$@" is special. Even if quoted, it can still
1744 * expand to nothing (not even an empty string) */
1745 if ((first_ch & 0x7f) != '@')
1746 ored_ch |= first_ch;
1749 switch (first_ch & 0x7f) {
1750 /* Highest bit in first_ch indicates that var is double-quoted */
1752 val = utoa(G.root_pid);
1754 case '!': /* bg pid */
1755 val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)"";
1757 case '?': /* exitcode */
1758 val = utoa(G.last_return_code);
1760 case '#': /* argc */
1761 if (arg[1] != SPECIAL_VAR_SYMBOL)
1762 /* actually, it's a ${#var} */
1764 val = utoa(G.global_argc ? G.global_argc-1 : 0);
1769 if (!G.global_argv[i])
1771 ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
1772 if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
1773 smallint sv = output->o_escape;
1774 /* unquoted var's contents should be globbed, so don't escape */
1775 output->o_escape = 0;
1776 while (G.global_argv[i]) {
1777 n = expand_on_ifs(output, n, G.global_argv[i]);
1778 debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
1779 if (G.global_argv[i++][0] && G.global_argv[i]) {
1780 /* this argv[] is not empty and not last:
1781 * put terminating NUL, start new word */
1782 o_addchr(output, '\0');
1783 debug_print_list("expand_vars_to_list[2]", output, n);
1784 n = o_save_ptr(output, n);
1785 debug_print_list("expand_vars_to_list[3]", output, n);
1788 output->o_escape = sv;
1790 /* If or_mask is nonzero, we handle assignment 'a=....$@.....'
1791 * and in this case should treat it like '$*' - see 'else...' below */
1792 if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */
1794 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1795 if (++i >= G.global_argc)
1797 o_addchr(output, '\0');
1798 debug_print_list("expand_vars_to_list[4]", output, n);
1799 n = o_save_ptr(output, n);
1801 } else { /* quoted $*: add as one word */
1803 o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i]));
1804 if (!G.global_argv[++i])
1807 o_addchr(output, G.ifs[0]);
1811 case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
1812 /* "Empty variable", used to make "" etc to not disappear */
1816 #if ENABLE_HUSH_TICK
1817 case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
1820 //TODO: can we just stuff it into "output" directly?
1821 debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
1822 process_command_subs(&subst_result, arg);
1823 debug_printf_subst("SUBST RES '%s'\n", subst_result.data);
1824 val = subst_result.data;
1827 #if ENABLE_SH_MATH_SUPPORT
1828 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
1829 arith_eval_hooks_t hooks;
1834 arg++; /* skip '+' */
1835 *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
1836 debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
1838 /* Optional: skip expansion if expr is simple ("a + 3", "i++" etc) */
1841 unsigned char c = *exp_str++;
1848 if (strchr(" \t+-*/%_", c) != NULL)
1850 c |= 0x20; /* tolower */
1851 if (c >= 'a' && c <= 'z')
1855 /* We need to expand. Example: "echo $(($a + 1)) $((1 + $((2)) ))" */
1857 struct in_str input;
1858 o_string dest = NULL_O_STRING;
1860 setup_string_in_str(&input, arg);
1861 parse_stream_dquoted(NULL, &dest, &input, EOF);
1862 //bb_error_msg("'%s' -> '%s'", arg, dest.data);
1863 exp_str = expand_string_to_string(dest.data);
1864 //bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
1868 hooks.lookupvar = get_local_var_value;
1869 hooks.setvar = arith_set_local_var;
1870 hooks.endofname = endofname;
1871 res = arith(exp_str ? exp_str : arg, &errcode, &hooks);
1876 case -3: maybe_die("arith", "exponent less than 0"); break;
1877 case -2: maybe_die("arith", "divide by zero"); break;
1878 case -5: maybe_die("arith", "expression recursion loop detected"); break;
1879 default: maybe_die("arith", "syntax error"); break;
1882 debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
1883 sprintf(arith_buf, arith_t_fmt, res);
1888 default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */
1890 bool exp_len = false, exp_null = false;
1891 char *var = arg, exp_save, exp_op, *exp_word;
1894 arg[0] = first_ch & 0x7f;
1896 /* prepare for expansions */
1897 if (var[0] == '#') {
1898 /* handle length expansion ${#var} */
1902 /* maybe handle parameter expansion */
1903 exp_off = strcspn(var, ":-=+?");
1907 exp_save = var[exp_off];
1908 exp_null = exp_save == ':';
1909 exp_word = var + exp_off;
1910 if (exp_null) ++exp_word;
1911 exp_op = *exp_word++;
1912 var[exp_off] = '\0';
1916 /* lookup the variable in question */
1917 if (isdigit(var[0])) {
1918 /* handle_dollar() should have vetted var for us */
1920 if (i < G.global_argc)
1921 val = G.global_argv[i];
1922 /* else val remains NULL: $N with too big N */
1924 val = get_local_var_value(var);
1926 /* handle any expansions */
1928 debug_printf_expand("expand: length of '%s' = ", val);
1929 val = utoa(val ? strlen(val) : 0);
1930 debug_printf_expand("%s\n", val);
1931 } else if (exp_off) {
1932 /* we need to do an expansion */
1933 int exp_test = (!val || (exp_null && !val[0]));
1935 exp_test = !exp_test;
1936 debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
1937 exp_null ? "true" : "false", exp_test);
1940 maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
1944 if (exp_op == '=') {
1945 if (isdigit(var[0]) || var[0] == '#') {
1946 maybe_die(var, "special vars cannot assign in this way");
1949 char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
1950 sprintf(new_var, "%s=%s", var, val);
1951 set_local_var(new_var, -1);
1955 var[exp_off] = exp_save;
1959 #if ENABLE_HUSH_TICK
1962 if (!(first_ch & 0x80)) { /* unquoted $VAR */
1963 debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape);
1965 /* unquoted var's contents should be globbed, so don't escape */
1966 smallint sv = output->o_escape;
1967 output->o_escape = 0;
1968 n = expand_on_ifs(output, n, val);
1970 output->o_escape = sv;
1972 } else { /* quoted $VAR, val will be appended below */
1973 debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape);
1976 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
1978 o_addQstr(output, val, strlen(val));
1980 /* Do the check to avoid writing to a const string */
1981 if (*p != SPECIAL_VAR_SYMBOL)
1982 *p = SPECIAL_VAR_SYMBOL;
1984 #if ENABLE_HUSH_TICK
1985 o_free(&subst_result);
1988 } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
1991 debug_print_list("expand_vars_to_list[a]", output, n);
1992 /* this part is literal, and it was already pre-quoted
1993 * if needed (much earlier), do not use o_addQstr here! */
1994 o_addstr_with_NUL(output, arg);
1995 debug_print_list("expand_vars_to_list[b]", output, n);
1996 } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
1997 && !(ored_ch & 0x80) /* and all vars were not quoted. */
2000 /* allow to reuse list[n] later without re-growth */
2001 output->has_empty_slot = 1;
2003 o_addchr(output, '\0');
2008 static char **expand_variables(char **argv, int or_mask)
2013 o_string output = NULL_O_STRING;
2015 if (or_mask & 0x100) {
2016 output.o_escape = 1; /* protect against globbing for "$var" */
2017 /* (unquoted $var will temporarily switch it off) */
2024 n = expand_vars_to_list(&output, n, *v, (char)or_mask);
2027 debug_print_list("expand_variables", &output, n);
2029 /* output.data (malloced in one block) gets returned in "list" */
2030 list = o_finalize_list(&output, n);
2031 debug_print_strings("expand_variables[1]", list);
2035 static char **expand_strvec_to_strvec(char **argv)
2037 return expand_variables(argv, 0x100);
2040 /* Used for expansion of right hand of assignments */
2041 /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs
2043 static char *expand_string_to_string(const char *str)
2045 char *argv[2], **list;
2047 argv[0] = (char*)str;
2049 list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */
2051 if (!list[0] || list[1])
2052 bb_error_msg_and_die("BUG in varexp2");
2053 /* actually, just move string 2*sizeof(char*) bytes back */
2054 overlapping_strcpy((char*)list, list[0]);
2055 debug_printf_expand("string_to_string='%s'\n", (char*)list);
2059 /* Used for "eval" builtin */
2060 static char* expand_strvec_to_string(char **argv)
2064 list = expand_variables(argv, 0x80);
2065 /* Convert all NULs to spaces */
2070 if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
2071 bb_error_msg_and_die("BUG in varexp3");
2072 list[n][-1] = ' '; /* TODO: or to G.ifs[0]? */
2076 overlapping_strcpy((char*)list, list[0]);
2077 debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
2081 static char **expand_assignments(char **argv, int count)
2085 /* Expand assignments into one string each */
2086 for (i = 0; i < count; i++) {
2087 p = add_string_to_strings(p, expand_string_to_string(argv[i]));
2093 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
2094 * and stderr if they are redirected. */
2095 static int setup_redirects(struct command *prog, int squirrel[])
2098 struct redir_struct *redir;
2100 for (redir = prog->redirects; redir; redir = redir->next) {
2101 if (redir->dup == -1 && redir->rd_filename == NULL) {
2102 /* something went wrong in the parse. Pretend it didn't happen */
2105 if (redir->dup == -1) {
2107 mode = redir_table[redir->rd_type].mode;
2108 //TODO: check redir for names like '\\'
2109 p = expand_string_to_string(redir->rd_filename);
2110 openfd = open_or_warn(p, mode);
2113 /* this could get lost if stderr has been redirected, but
2114 bash and ash both lose it as well (though zsh doesn't!) */
2118 openfd = redir->dup;
2121 if (openfd != redir->fd) {
2122 if (squirrel && redir->fd < 3) {
2123 squirrel[redir->fd] = dup(redir->fd);
2126 //close(openfd); // close(-3) ??!
2128 dup2(openfd, redir->fd);
2129 if (redir->dup == -1)
2137 static void restore_redirects(int squirrel[])
2140 for (i = 0; i < 3; i++) {
2143 /* We simply die on error */
2150 #if !defined(DEBUG_CLEAN)
2151 #define free_pipe_list(head, indent) free_pipe_list(head)
2152 #define free_pipe(pi, indent) free_pipe(pi)
2154 static void free_pipe_list(struct pipe *head, int indent);
2156 /* Return code is the exit status of the pipe */
2157 static void free_pipe(struct pipe *pi, int indent)
2160 struct command *command;
2161 struct redir_struct *r, *rnext;
2164 if (pi->stopped_cmds > 0) /* why? */
2166 debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
2167 for (i = 0; i < pi->num_cmds; i++) {
2168 command = &pi->cmds[i];
2169 debug_printf_clean("%s command %d:\n", indenter(indent), i);
2170 if (command->argv) {
2171 for (a = 0, p = command->argv; *p; a++, p++) {
2172 debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p);
2174 free_strings(command->argv);
2175 command->argv = NULL;
2177 /* not "else if": on syntax error, we may have both! */
2178 if (command->group) {
2179 debug_printf_clean("%s begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
2180 free_pipe_list(command->group, indent+3);
2181 debug_printf_clean("%s end group\n", indenter(indent));
2182 command->group = NULL;
2185 free(command->group_as_string);
2186 command->group_as_string = NULL;
2188 for (r = command->redirects; r; r = rnext) {
2189 debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->rd_type].descrip);
2191 /* guard against the case >$FOO, where foo is unset or blank */
2192 if (r->rd_filename) {
2193 debug_printf_clean(" %s\n", r->rd_filename);
2194 free(r->rd_filename);
2195 r->rd_filename = NULL;
2198 debug_printf_clean("&%d\n", r->dup);
2203 command->redirects = NULL;
2205 free(pi->cmds); /* children are an array, they get freed all at once */
2213 static void free_pipe_list(struct pipe *head, int indent)
2215 struct pipe *pi, *next;
2217 for (pi = head; pi; pi = next) {
2219 debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word);
2221 free_pipe(pi, indent);
2222 debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup);
2224 /*pi->next = NULL;*/
2231 typedef struct nommu_save_t {
2237 #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
2238 pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
2239 #define pseudo_exec(nommu_save, command, argv_expanded) \
2240 pseudo_exec(command, argv_expanded)
2243 /* Called after [v]fork() in run_pipe(), or from builtin_exec().
2245 * XXX no exit() here. If you don't exec, use _exit instead.
2246 * The at_exit handlers apparently confuse the calling process,
2247 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
2248 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2249 char **argv, int assignment_cnt,
2250 char **argv_expanded) NORETURN;
2251 static void pseudo_exec_argv(nommu_save_t *nommu_save,
2252 char **argv, int assignment_cnt,
2253 char **argv_expanded)
2257 /* Case when we are here: ... | var=val | ... */
2258 if (!argv[assignment_cnt])
2259 _exit(EXIT_SUCCESS);
2261 new_env = expand_assignments(argv, assignment_cnt);
2263 putenv_all(new_env);
2264 free(new_env); /* optional */
2266 nommu_save->new_env = new_env;
2267 nommu_save->old_env = putenv_all_and_save_old(new_env);
2269 if (argv_expanded) {
2270 argv = argv_expanded;
2272 argv = expand_strvec_to_strvec(argv + assignment_cnt);
2274 nommu_save->argv = argv;
2278 /* On NOMMU, we must never block!
2279 * Example: { sleep 99999 | read line } & echo Ok
2280 * read builtin will block on read syscall, leaving parent blocked
2281 * in vfork. Therefore we can't do this:
2284 /* Check if the command matches any of the builtins.
2285 * Depending on context, this might be redundant. But it's
2286 * easier to waste a few CPU cycles than it is to figure out
2287 * if this is one of those cases.
2291 const struct built_in_command *x;
2292 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2293 if (strcmp(argv[0], x->cmd) == 0) {
2294 debug_printf_exec("running builtin '%s'\n",
2296 rcode = x->function(argv);
2304 #if ENABLE_FEATURE_SH_STANDALONE
2305 /* Check if the command matches any busybox applets */
2306 if (strchr(argv[0], '/') == NULL) {
2307 int a = find_applet_by_name(argv[0]);
2309 #if BB_MMU /* see above why on NOMMU it is not allowed */
2310 if (APPLET_IS_NOEXEC(a)) {
2311 debug_printf_exec("running applet '%s'\n", argv[0]);
2312 run_applet_no_and_exit(a, argv);
2315 /* Re-exec ourselves */
2316 debug_printf_exec("re-execing applet '%s'\n", argv[0]);
2317 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2318 execv(bb_busybox_exec_path, argv);
2319 /* If they called chroot or otherwise made the binary no longer
2320 * executable, fall through */
2325 debug_printf_exec("execing '%s'\n", argv[0]);
2326 sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
2327 execvp(argv[0], argv);
2328 bb_perror_msg("can't exec '%s'", argv[0]);
2329 _exit(EXIT_FAILURE);
2332 static void re_execute_shell(const char *s) NORETURN;
2333 static void re_execute_shell(const char *s)
2335 //TODO: pass non-exported variables, traps, and functions
2336 debug_printf_exec("re_execute_shell pid:%d cmd:'%s'", getpid(), s);
2337 execl(bb_busybox_exec_path, "hush", "-c", s, NULL);
2338 //TODO: fallback for init=/bin/hush?
2342 static int run_list(struct pipe *pi);
2344 /* Called after [v]fork() in run_pipe()
2346 static void pseudo_exec(nommu_save_t *nommu_save,
2347 struct command *command,
2348 char **argv_expanded) NORETURN;
2349 static void pseudo_exec(nommu_save_t *nommu_save,
2350 struct command *command,
2351 char **argv_expanded)
2353 if (command->argv) {
2354 pseudo_exec_argv(nommu_save, command->argv,
2355 command->assignment_cnt, argv_expanded);
2358 if (command->group) {
2359 /* Cases when we are here:
2362 * ... | ( list ) | ...
2363 * ... | { list } | ...
2367 debug_printf_exec("pseudo_exec: run_list\n");
2368 rcode = run_list(command->group);
2369 /* OK to leak memory by not calling free_pipe_list,
2370 * since this process is about to exit */
2373 re_execute_shell(command->group_as_string);
2377 /* Case when we are here: ... | >file */
2378 debug_printf_exec("pseudo_exec'ed null command\n");
2379 _exit(EXIT_SUCCESS);
2383 static const char *get_cmdtext(struct pipe *pi)
2389 /* This is subtle. ->cmdtext is created only on first backgrounding.
2390 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
2391 * On subsequent bg argv is trashed, but we won't use it */
2394 argv = pi->cmds[0].argv;
2395 if (!argv || !argv[0]) {
2396 pi->cmdtext = xzalloc(1);
2401 do len += strlen(*argv) + 1; while (*++argv);
2402 pi->cmdtext = p = xmalloc(len);
2403 argv = pi->cmds[0].argv;
2405 len = strlen(*argv);
2406 memcpy(p, *argv, len);
2414 static void insert_bg_job(struct pipe *pi)
2416 struct pipe *thejob;
2419 /* Linear search for the ID of the job to use */
2421 for (thejob = G.job_list; thejob; thejob = thejob->next)
2422 if (thejob->jobid >= pi->jobid)
2423 pi->jobid = thejob->jobid + 1;
2425 /* Add thejob to the list of running jobs */
2427 thejob = G.job_list = xmalloc(sizeof(*thejob));
2429 for (thejob = G.job_list; thejob->next; thejob = thejob->next)
2431 thejob->next = xmalloc(sizeof(*thejob));
2432 thejob = thejob->next;
2435 /* Physically copy the struct job */
2436 memcpy(thejob, pi, sizeof(struct pipe));
2437 thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
2438 /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */
2439 for (i = 0; i < pi->num_cmds; i++) {
2440 // TODO: do we really need to have so many fields which are just dead weight
2441 // at execution stage?
2442 thejob->cmds[i].pid = pi->cmds[i].pid;
2443 /* all other fields are not used and stay zero */
2445 thejob->next = NULL;
2446 thejob->cmdtext = xstrdup(get_cmdtext(pi));
2448 /* We don't wait for background thejobs to return -- append it
2449 to the list of backgrounded thejobs and leave it alone */
2450 if (G_interactive_fd)
2451 printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext);
2452 G.last_bg_pid = thejob->cmds[0].pid;
2453 G.last_jobid = thejob->jobid;
2456 static void remove_bg_job(struct pipe *pi)
2458 struct pipe *prev_pipe;
2460 if (pi == G.job_list) {
2461 G.job_list = pi->next;
2463 prev_pipe = G.job_list;
2464 while (prev_pipe->next != pi)
2465 prev_pipe = prev_pipe->next;
2466 prev_pipe->next = pi->next;
2469 G.last_jobid = G.job_list->jobid;
2474 /* Remove a backgrounded job */
2475 static void delete_finished_bg_job(struct pipe *pi)
2478 pi->stopped_cmds = 0;
2484 /* Check to see if any processes have exited -- if they
2485 * have, figure out why and see if a job has completed */
2486 static int checkjobs(struct pipe* fg_pipe)
2496 debug_printf_jobs("checkjobs %p\n", fg_pipe);
2499 // if (G.handled_SIGCHLD == G.count_SIGCHLD)
2500 // /* avoid doing syscall, nothing there anyway */
2503 attributes = WUNTRACED;
2504 if (fg_pipe == NULL)
2505 attributes |= WNOHANG;
2507 /* Do we do this right?
2508 * bash-3.00# sleep 20 | false
2510 * [3]+ Stopped sleep 20 | false
2511 * bash-3.00# echo $?
2512 * 1 <========== bg pipe is not fully done, but exitcode is already known!
2515 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
2516 //are stopped. Testcase: "cat | cat" in a script (not on command line)
2517 // + killall -STOP cat
2524 // i = G.count_SIGCHLD;
2525 childpid = waitpid(-1, &status, attributes);
2526 if (childpid <= 0) {
2527 if (childpid && errno != ECHILD)
2528 bb_perror_msg("waitpid");
2529 // else /* Until next SIGCHLD, waitpid's are useless */
2530 // G.handled_SIGCHLD = i;
2533 dead = WIFEXITED(status) || WIFSIGNALED(status);
2536 if (WIFSTOPPED(status))
2537 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
2538 childpid, WSTOPSIG(status), WEXITSTATUS(status));
2539 if (WIFSIGNALED(status))
2540 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
2541 childpid, WTERMSIG(status), WEXITSTATUS(status));
2542 if (WIFEXITED(status))
2543 debug_printf_jobs("pid %d exited, exitcode %d\n",
2544 childpid, WEXITSTATUS(status));
2546 /* Were we asked to wait for fg pipe? */
2548 for (i = 0; i < fg_pipe->num_cmds; i++) {
2549 debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
2550 if (fg_pipe->cmds[i].pid != childpid)
2552 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
2554 fg_pipe->cmds[i].pid = 0;
2555 fg_pipe->alive_cmds--;
2556 if (i == fg_pipe->num_cmds - 1) {
2557 /* last process gives overall exitstatus */
2558 rcode = WEXITSTATUS(status);
2559 IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
2562 fg_pipe->cmds[i].is_stopped = 1;
2563 fg_pipe->stopped_cmds++;
2565 debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
2566 fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
2567 if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) {
2568 /* All processes in fg pipe have exited/stopped */
2570 if (fg_pipe->alive_cmds)
2571 insert_bg_job(fg_pipe);
2575 /* There are still running processes in the fg pipe */
2576 goto wait_more; /* do waitpid again */
2578 /* it wasnt fg_pipe, look for process in bg pipes */
2582 /* We asked to wait for bg or orphaned children */
2583 /* No need to remember exitcode in this case */
2584 for (pi = G.job_list; pi; pi = pi->next) {
2585 for (i = 0; i < pi->num_cmds; i++) {
2586 if (pi->cmds[i].pid == childpid)
2587 goto found_pi_and_prognum;
2590 /* Happens when shell is used as init process (init=/bin/sh) */
2591 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
2592 continue; /* do waitpid again */
2594 found_pi_and_prognum:
2597 pi->cmds[i].pid = 0;
2599 if (!pi->alive_cmds) {
2600 if (G_interactive_fd)
2601 printf(JOB_STATUS_FORMAT, pi->jobid,
2602 "Done", pi->cmdtext);
2603 delete_finished_bg_job(pi);
2607 pi->cmds[i].is_stopped = 1;
2611 } /* while (waitpid succeeds)... */
2617 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
2620 int rcode = checkjobs(fg_pipe);
2621 /* Job finished, move the shell to the foreground */
2622 p = getpgid(0); /* pgid of our process */
2623 debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
2624 tcsetpgrp(G_interactive_fd, p);
2629 /* Start all the jobs, but don't wait for anything to finish.
2632 * Return code is normally -1, when the caller has to wait for children
2633 * to finish to determine the exit status of the pipe. If the pipe
2634 * is a simple builtin command, however, the action is done by the
2635 * time run_pipe returns, and the exit code is provided as the
2638 * Returns -1 only if started some children. IOW: we have to
2639 * mask out retvals of builtins etc with 0xff!
2641 * The only case when we do not need to [v]fork is when the pipe
2642 * is single, non-backgrounded, non-subshell command. Examples:
2643 * cmd ; ... { list } ; ...
2644 * cmd && ... { list } && ...
2645 * cmd || ... { list } || ...
2646 * If it is, then we can run cmd as a builtin, NOFORK [do we do this?],
2647 * or (if SH_STANDALONE) an applet, and we can run the { list }
2648 * with run_list(). If it isn't one of these, we fork and exec cmd.
2650 * Cases when we must fork:
2651 * non-single: cmd | cmd
2652 * backgrounded: cmd & { list } &
2653 * subshell: ( list ) [&]
2655 static int run_pipe(struct pipe *pi)
2657 static const char *const null_ptr = NULL;
2660 int pipefds[2]; /* pipefds[0] is for reading */
2661 struct command *command;
2662 char **argv_expanded;
2665 /* it is not always needed, but we aim to smaller code */
2666 int squirrel[] = { -1, -1, -1 };
2669 debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
2671 USE_HUSH_JOB(pi->pgrp = -1;)
2672 pi->stopped_cmds = 0;
2673 command = &(pi->cmds[0]);
2674 argv_expanded = NULL;
2676 if (pi->num_cmds != 1
2677 || pi->followup == PIPE_BG
2678 || command->grp_type == GRP_SUBSHELL
2685 debug_printf_exec(": group:%p argv:'%s'\n",
2686 command->group, command->argv ? command->argv[0] : "NONE");
2688 if (command->group) {
2689 #if ENABLE_HUSH_FUNCTIONS
2690 if (command->grp_type == GRP_FUNCTION) {
2691 /* func () { list } */
2692 bb_error_msg("here we ought to remember function definition, and go on");
2693 return EXIT_SUCCESS;
2697 debug_printf("non-subshell group\n");
2698 setup_redirects(command, squirrel);
2699 debug_printf_exec(": run_list\n");
2700 rcode = run_list(command->group) & 0xff;
2701 restore_redirects(squirrel);
2702 debug_printf_exec("run_pipe return %d\n", rcode);
2703 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2707 argv = command->argv ? command->argv : (char **) &null_ptr;
2709 const struct built_in_command *x;
2710 char **new_env = NULL;
2711 char **old_env = NULL;
2713 if (argv[command->assignment_cnt] == NULL) {
2714 /* Assignments, but no command */
2715 /* Ensure redirects take effect. Try "a=t >file" */
2716 setup_redirects(command, squirrel);
2717 restore_redirects(squirrel);
2718 /* Set shell variables */
2720 p = expand_string_to_string(*argv);
2721 debug_printf_exec("set shell var:'%s'->'%s'\n",
2723 set_local_var(p, 0);
2726 /* Do we need to flag set_local_var() errors?
2727 * "assignment to readonly var" and "putenv error"
2729 return EXIT_SUCCESS;
2732 /* Expand the rest into (possibly) many strings each */
2733 argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
2735 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
2736 if (strcmp(argv_expanded[0], x->cmd) != 0)
2738 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
2739 debug_printf("exec with redirects only\n");
2740 setup_redirects(command, NULL);
2741 rcode = EXIT_SUCCESS;
2742 goto clean_up_and_ret1;
2744 debug_printf("builtin inline %s\n", argv_expanded[0]);
2745 /* XXX setup_redirects acts on file descriptors, not FILEs.
2746 * This is perfect for work that comes after exec().
2747 * Is it really safe for inline use? Experimentally,
2748 * things seem to work with glibc. */
2749 setup_redirects(command, squirrel);
2750 new_env = expand_assignments(argv, command->assignment_cnt);
2751 old_env = putenv_all_and_save_old(new_env);
2752 debug_printf_exec(": builtin '%s' '%s'...\n",
2753 x->cmd, argv_expanded[1]);
2754 rcode = x->function(argv_expanded) & 0xff;
2755 #if ENABLE_FEATURE_SH_STANDALONE
2758 restore_redirects(squirrel);
2759 free_strings_and_unsetenv(new_env, 1);
2760 putenv_all(old_env);
2761 free(old_env); /* not free_strings()! */
2763 free(argv_expanded);
2764 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
2765 debug_printf_exec("run_pipe return %d\n", rcode);
2768 #if ENABLE_FEATURE_SH_STANDALONE
2769 i = find_applet_by_name(argv_expanded[0]);
2770 if (i >= 0 && APPLET_IS_NOFORK(i)) {
2771 setup_redirects(command, squirrel);
2772 save_nofork_data(&G.nofork_save);
2773 new_env = expand_assignments(argv, command->assignment_cnt);
2774 old_env = putenv_all_and_save_old(new_env);
2775 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
2776 argv_expanded[0], argv_expanded[1]);
2777 rcode = run_nofork_applet_prime(&G.nofork_save, i, argv_expanded);
2778 goto clean_up_and_ret;
2781 /* It is neither builtin nor applet. We must fork. */
2785 /* NB: argv_expanded may already be created, and that
2786 * might include `cmd` runs! Do not rerun it! We *must*
2787 * use argv_expanded if it's non-NULL */
2789 /* Going to fork a child per each pipe member */
2793 for (i = 0; i < pi->num_cmds; i++) {
2795 volatile nommu_save_t nommu_save;
2796 nommu_save.new_env = NULL;
2797 nommu_save.old_env = NULL;
2798 nommu_save.argv = NULL;
2800 command = &(pi->cmds[i]);
2801 if (command->argv) {
2802 debug_printf_exec(": pipe member '%s' '%s'...\n",
2803 command->argv[0], command->argv[1]);
2805 debug_printf_exec(": pipe member with no argv\n");
2808 /* pipes are inserted between pairs of commands */
2811 if ((i + 1) < pi->num_cmds)
2814 command->pid = BB_MMU ? fork() : vfork();
2815 if (!command->pid) { /* child */
2817 die_sleep = 0; /* let nofork's xfuncs die */
2819 /* Every child adds itself to new process group
2820 * with pgid == pid_of_first_child_in_pipe */
2821 if (G.run_list_level == 1 && G_interactive_fd) {
2824 if (pgrp < 0) /* true for 1st process only */
2826 if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
2827 /* We do it in *every* child, not just first,
2829 tcsetpgrp(G_interactive_fd, pgrp);
2833 xmove_fd(nextin, 0);
2834 xmove_fd(pipefds[1], 1); /* write end */
2836 close(pipefds[0]); /* read end */
2837 /* Like bash, explicit redirects override pipes,
2838 * and the pipe fd is available for dup'ing. */
2839 setup_redirects(command, NULL);
2841 /* Restore default handlers just prior to exec */
2842 /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */
2844 /* Stores to nommu_save list of env vars putenv'ed
2845 * (NOMMU, on MMU we don't need that) */
2846 /* cast away volatility... */
2847 pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
2848 /* pseudo_exec() does not return */
2852 /* Clean up after vforked child */
2853 free(nommu_save.argv);
2854 free_strings_and_unsetenv(nommu_save.new_env, 1);
2855 putenv_all(nommu_save.old_env);
2857 free(argv_expanded);
2858 argv_expanded = NULL;
2859 if (command->pid < 0) { /* [v]fork failed */
2860 /* Clearly indicate, was it fork or vfork */
2861 bb_perror_msg(BB_MMU ? "fork" : "vfork");
2865 /* Second and next children need to know pid of first one */
2867 pi->pgrp = command->pid;
2873 if ((i + 1) < pi->num_cmds)
2874 close(pipefds[1]); /* write end */
2875 /* Pass read (output) pipe end to next iteration */
2876 nextin = pipefds[0];
2879 if (!pi->alive_cmds) {
2880 debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
2884 debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
2888 #ifndef debug_print_tree
2889 static void debug_print_tree(struct pipe *pi, int lvl)
2891 static const char *const PIPE[] = {
2897 static const char *RES[] = {
2898 [RES_NONE ] = "NONE" ,
2901 [RES_THEN ] = "THEN" ,
2902 [RES_ELIF ] = "ELIF" ,
2903 [RES_ELSE ] = "ELSE" ,
2906 #if ENABLE_HUSH_LOOPS
2907 [RES_FOR ] = "FOR" ,
2908 [RES_WHILE] = "WHILE",
2909 [RES_UNTIL] = "UNTIL",
2911 [RES_DONE ] = "DONE" ,
2913 #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
2916 #if ENABLE_HUSH_CASE
2917 [RES_CASE ] = "CASE" ,
2918 [RES_MATCH] = "MATCH",
2919 [RES_CASEI] = "CASEI",
2920 [RES_ESAC ] = "ESAC" ,
2922 [RES_XXXX ] = "XXXX" ,
2923 [RES_SNTX ] = "SNTX" ,
2925 static const char *const GRPTYPE[] = {
2928 #if ENABLE_HUSH_FUNCTIONS
2937 fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
2938 pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
2940 while (prn < pi->num_cmds) {
2941 struct command *command = &pi->cmds[prn];
2942 char **argv = command->argv;
2944 fprintf(stderr, "%*s prog %d assignment_cnt:%d",
2946 command->assignment_cnt);
2947 if (command->group) {
2948 fprintf(stderr, " group %s: (argv=%p)\n",
2949 GRPTYPE[command->grp_type],
2951 debug_print_tree(command->group, lvl+1);
2955 if (argv) while (*argv) {
2956 fprintf(stderr, " '%s'", *argv);
2959 fprintf(stderr, "\n");
2968 /* NB: called by pseudo_exec, and therefore must not modify any
2969 * global data until exec/_exit (we can be a child after vfork!) */
2970 static int run_list(struct pipe *pi)
2972 #if ENABLE_HUSH_CASE
2973 char *case_word = NULL;
2975 #if ENABLE_HUSH_LOOPS
2976 struct pipe *loop_top = NULL;
2977 char *for_varname = NULL;
2978 char **for_lcur = NULL;
2979 char **for_list = NULL;
2981 smallint flag_skip = 1;
2982 smalluint rcode = 0; /* probably just for compiler */
2983 #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
2984 smalluint cond_code = 0;
2986 enum { cond_code = 0, };
2988 /*enum reserved_style*/ smallint rword = RES_NONE;
2989 /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX;
2991 debug_printf_exec("run_list start lvl %d\n", G.run_list_level + 1);
2993 #if ENABLE_HUSH_LOOPS
2994 /* Check syntax for "for" */
2995 for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) {
2996 if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
2998 /* current word is FOR or IN (BOLD in comments below) */
2999 if (cpipe->next == NULL) {
3000 syntax("malformed for");
3001 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3004 /* "FOR v; do ..." and "for v IN a b; do..." are ok */
3005 if (cpipe->next->res_word == RES_DO)
3007 /* next word is not "do". It must be "in" then ("FOR v in ...") */
3008 if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
3009 || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
3011 syntax("malformed for");
3012 debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
3018 /* Past this point, all code paths should jump to ret: label
3019 * in order to return, no direct "return" statements please.
3020 * This helps to ensure that no memory is leaked. */
3022 ////TODO: ctrl-Z handling needs re-thinking and re-testing
3025 /* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
3026 * We are saving state before entering outermost list ("while...done")
3027 * so that ctrl-Z will correctly background _entire_ outermost list,
3028 * not just a part of it (like "sleep 1 | exit 2") */
3029 if (++G.run_list_level == 1 && G_interactive_fd) {
3030 if (sigsetjmp(G.toplevel_jb, 1)) {
3031 /* ctrl-Z forked and we are parent; or ctrl-C.
3032 * Sighandler has longjmped us here */
3033 signal(SIGINT, SIG_IGN);
3034 signal(SIGTSTP, SIG_IGN);
3035 /* Restore level (we can be coming from deep inside
3037 G.run_list_level = 1;
3038 #if ENABLE_FEATURE_SH_STANDALONE
3039 if (G.nofork_save.saved) { /* if save area is valid */
3040 debug_printf_jobs("exiting nofork early\n");
3041 restore_nofork_data(&G.nofork_save);
3044 //// if (G.ctrl_z_flag) {
3045 //// /* ctrl-Z has forked and stored pid of the child in pi->pid.
3046 //// * Remember this child as background job */
3047 //// insert_bg_job(pi);
3049 /* ctrl-C. We just stop doing whatever we were doing */
3052 USE_HUSH_LOOPS(loop_top = NULL;)
3053 USE_HUSH_LOOPS(G.depth_of_loop = 0;)
3057 //// /* ctrl-Z handler will store pid etc in pi */
3058 //// G.toplevel_list = pi;
3059 //// G.ctrl_z_flag = 0;
3060 ////#if ENABLE_FEATURE_SH_STANDALONE
3061 //// G.nofork_save.saved = 0; /* in case we will run a nofork later */
3063 //// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
3064 //// signal(SIGINT, handler_ctrl_c);
3068 /* Go through list of pipes, (maybe) executing them. */
3069 for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
3073 IF_HAS_KEYWORDS(rword = pi->res_word;)
3074 IF_HAS_NO_KEYWORDS(rword = RES_NONE;)
3075 debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n",
3076 rword, cond_code, skip_more_for_this_rword);
3077 #if ENABLE_HUSH_LOOPS
3078 if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
3079 && loop_top == NULL /* avoid bumping G.depth_of_loop twice */
3081 /* start of a loop: remember where loop starts */
3086 if (rword == skip_more_for_this_rword && flag_skip) {
3087 if (pi->followup == PIPE_SEQ)
3089 /* it is "<false> && CMD" or "<true> || CMD"
3090 * and we should not execute CMD */
3094 skip_more_for_this_rword = RES_XXXX;
3097 if (rword == RES_THEN) {
3098 /* "if <false> THEN cmd": skip cmd */
3102 if (rword == RES_ELSE || rword == RES_ELIF) {
3103 /* "if <true> then ... ELSE/ELIF cmd":
3104 * skip cmd and all following ones */
3109 #if ENABLE_HUSH_LOOPS
3110 if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
3112 /* first loop through for */
3114 static const char encoded_dollar_at[] ALIGN1 = {
3115 SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
3116 }; /* encoded representation of "$@" */
3117 static const char *const encoded_dollar_at_argv[] = {
3118 encoded_dollar_at, NULL
3119 }; /* argv list with one element: "$@" */
3122 vals = (char**)encoded_dollar_at_argv;
3123 if (pi->next->res_word == RES_IN) {
3124 /* if no variable values after "in" we skip "for" */
3125 if (!pi->next->cmds[0].argv)
3127 vals = pi->next->cmds[0].argv;
3128 } /* else: "for var; do..." -> assume "$@" list */
3129 /* create list of variable values */
3130 debug_print_strings("for_list made from", vals);
3131 for_list = expand_strvec_to_strvec(vals);
3132 for_lcur = for_list;
3133 debug_print_strings("for_list", for_list);
3134 for_varname = pi->cmds[0].argv[0];
3135 pi->cmds[0].argv[0] = NULL;
3137 free(pi->cmds[0].argv[0]);
3139 /* "for" loop is over, clean up */
3143 pi->cmds[0].argv[0] = for_varname;
3146 /* insert next value from for_lcur */
3147 //TODO: does it need escaping?
3148 pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
3149 pi->cmds[0].assignment_cnt = 1;
3151 if (rword == RES_IN) {
3152 continue; /* "for v IN list;..." - "in" has no cmds anyway */
3154 if (rword == RES_DONE) {
3155 continue; /* "done" has no cmds too */
3158 #if ENABLE_HUSH_CASE
3159 if (rword == RES_CASE) {
3160 case_word = expand_strvec_to_string(pi->cmds->argv);
3163 if (rword == RES_MATCH) {
3166 if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
3168 /* all prev words didn't match, does this one match? */
3169 argv = pi->cmds->argv;
3171 char *pattern = expand_string_to_string(*argv);
3172 /* TODO: which FNM_xxx flags to use? */
3173 cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
3175 if (cond_code == 0) { /* match! we will execute this branch */
3176 free(case_word); /* make future "word)" stop */
3184 if (rword == RES_CASEI) { /* inside of a case branch */
3186 continue; /* not matched yet, skip this pipe */
3189 /* Just pressing <enter> in shell should check for jobs.
3190 * OTOH, in non-interactive shell this is useless
3191 * and only leads to extra job checks */
3192 if (pi->num_cmds == 0) {
3193 if (G_interactive_fd)
3194 goto check_jobs_and_continue;
3198 /* After analyzing all keywords and conditions, we decided
3199 * to execute this pipe. NB: have to do checkjobs(NULL)
3200 * after run_pipe() to collect any background children,
3201 * even if list execution is to be stopped. */
3202 debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
3205 #if ENABLE_HUSH_LOOPS
3206 G.flag_break_continue = 0;
3208 rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
3210 /* we only ran a builtin: rcode is already known
3211 * and we don't need to wait for anything. */
3212 check_and_run_traps(0);
3213 #if ENABLE_HUSH_LOOPS
3214 /* was it "break" or "continue"? */
3215 if (G.flag_break_continue) {
3216 smallint fbc = G.flag_break_continue;
3217 /* we might fall into outer *loop*,
3218 * don't want to break it too */
3220 G.depth_break_continue--;
3221 if (G.depth_break_continue == 0)
3222 G.flag_break_continue = 0;
3223 /* else: e.g. "continue 2" should *break* once, *then* continue */
3224 } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
3225 if (G.depth_break_continue != 0 || fbc == BC_BREAK)
3226 goto check_jobs_and_break;
3227 /* "continue": simulate end of loop */
3232 } else if (pi->followup == PIPE_BG) {
3233 /* what does bash do with attempts to background builtins? */
3234 /* even bash 3.2 doesn't do that well with nested bg:
3235 * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
3236 * I'm NOT treating inner &'s as jobs */
3237 check_and_run_traps(0);
3239 if (G.run_list_level == 1)
3242 rcode = 0; /* EXIT_SUCCESS */
3245 if (G.run_list_level == 1 && G_interactive_fd) {
3246 /* waits for completion, then fg's main shell */
3247 rcode = checkjobs_and_fg_shell(pi);
3248 check_and_run_traps(0);
3249 debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
3252 { /* this one just waits for completion */
3253 rcode = checkjobs(pi);
3254 check_and_run_traps(0);
3255 debug_printf_exec(": checkjobs returned %d\n", rcode);
3259 debug_printf_exec(": setting last_return_code=%d\n", rcode);
3260 G.last_return_code = rcode;
3262 /* Analyze how result affects subsequent commands */
3264 if (rword == RES_IF || rword == RES_ELIF)
3267 #if ENABLE_HUSH_LOOPS
3268 if (rword == RES_WHILE) {
3270 rcode = 0; /* "while false; do...done" - exitcode 0 */
3271 goto check_jobs_and_break;
3274 if (rword == RES_UNTIL) {
3276 check_jobs_and_break:
3282 if ((rcode == 0 && pi->followup == PIPE_OR)
3283 || (rcode != 0 && pi->followup == PIPE_AND)
3285 skip_more_for_this_rword = rword;
3288 check_jobs_and_continue:
3293 //// if (G.ctrl_z_flag) {
3294 //// /* ctrl-Z forked somewhere in the past, we are the child,
3295 //// * and now we completed running the list. Exit. */
3301 //// if (!G.run_list_level && G_interactive_fd) {
3302 //// signal(SIGTSTP, SIG_IGN);
3303 //// signal(SIGINT, SIG_IGN);
3306 debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
3307 #if ENABLE_HUSH_LOOPS
3312 #if ENABLE_HUSH_CASE
3318 /* Select which version we will use */
3319 static int run_and_free_list(struct pipe *pi)
3322 debug_printf_exec("run_and_free_list entered\n");
3324 debug_printf_exec(": run_list with %d members\n", pi->num_cmds);
3325 rcode = run_list(pi);
3327 /* free_pipe_list has the side effect of clearing memory.
3328 * In the long run that function can be merged with run_list,
3329 * but doing that now would hobble the debugging effort. */
3330 free_pipe_list(pi, /* indent: */ 0);
3331 debug_printf_exec("run_and_free_list return %d\n", rcode);
3336 /* Peek ahead in the in_str to find out if we have a "&n" construct,
3337 * as in "2>&1", that represents duplicating a file descriptor.
3338 * Return either -2 (syntax error), -1 (no &), or the number found.
3340 static int redirect_dup_num(struct in_str *input)
3342 int ch, d = 0, ok = 0;
3344 if (ch != '&') return -1;
3346 i_getch(input); /* get the & */
3350 return -3; /* "-" represents "close me" */
3352 while (isdigit(ch)) {
3353 d = d*10 + (ch-'0');
3360 bb_error_msg("ambiguous redirect");
3364 /* The src parameter allows us to peek forward to a possible &n syntax
3365 * for file descriptor duplication, e.g., "2>&1".
3366 * Return code is 0 normally, 1 if a syntax error is detected in src.
3367 * Resource errors (in xmalloc) cause the process to exit */
3368 static int setup_redirect(struct parse_context *ctx,
3371 struct in_str *input)
3373 struct command *command = ctx->command;
3374 struct redir_struct *redir;
3375 struct redir_struct **redirp;
3378 /* Check for a '2>&1' type redirect */
3379 dup_num = redirect_dup_num(input);
3381 return 1; /* syntax error */
3383 /* Create a new redir_struct and drop it onto the end of the linked list */
3384 redirp = &command->redirects;
3385 while ((redir = *redirp) != NULL) {
3386 redirp = &(redir->next);
3388 *redirp = redir = xzalloc(sizeof(*redir));
3389 /* redir->next = NULL; */
3390 /* redir->rd_filename = NULL; */
3391 redir->rd_type = style;
3392 redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
3394 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
3396 redir->dup = dup_num;
3397 if (dup_num != -1) {
3398 /* Erik had a check here that the file descriptor in question
3399 * is legit; I postpone that to "run time"
3400 * A "-" representation of "close me" shows up as a -3 here */
3401 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
3403 /* We do _not_ try to open the file that src points to,
3404 * since we need to return and let src be expanded first.
3405 * Set ctx->pending_redirect, so we know what to do at the
3406 * end of the next parsed word. */
3407 ctx->pending_redirect = redir;
3413 static struct pipe *new_pipe(void)
3416 pi = xzalloc(sizeof(struct pipe));
3417 /*pi->followup = 0; - deliberately invalid value */
3418 /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
3422 /* Command (member of a pipe) is complete. The only possible error here
3423 * is out of memory, in which case xmalloc exits. */
3424 static int done_command(struct parse_context *ctx)
3426 /* The command is really already in the pipe structure, so
3427 * advance the pipe counter and make a new, null command. */
3428 struct pipe *pi = ctx->pipe;
3429 struct command *command = ctx->command;
3432 if (command->group == NULL
3433 && command->argv == NULL
3434 && command->redirects == NULL
3436 debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
3437 return pi->num_cmds;
3440 debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
3442 debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
3445 /* Only real trickiness here is that the uncommitted
3446 * command structure is not counted in pi->num_cmds. */
3447 pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
3448 command = &pi->cmds[pi->num_cmds];
3449 memset(command, 0, sizeof(*command));
3451 ctx->command = command;
3452 /* but ctx->pipe and ctx->list_head remain unchanged */
3454 return pi->num_cmds; /* used only for 0/nonzero check */
3457 static void done_pipe(struct parse_context *ctx, pipe_style type)
3461 debug_printf_parse("done_pipe entered, followup %d\n", type);
3462 /* Close previous command */
3463 not_null = done_command(ctx);
3464 ctx->pipe->followup = type;
3465 IF_HAS_KEYWORDS(ctx->pipe->pi_inverted = ctx->ctx_inverted;)
3466 IF_HAS_KEYWORDS(ctx->ctx_inverted = 0;)
3467 IF_HAS_KEYWORDS(ctx->pipe->res_word = ctx->ctx_res_w;)
3469 /* Without this check, even just <enter> on command line generates
3470 * tree of three NOPs (!). Which is harmless but annoying.
3471 * IOW: it is safe to do it unconditionally.
3472 * RES_NONE case is for "for a in; do ..." (empty IN set)
3473 * to work, possibly other cases too. */
3474 if (not_null IF_HAS_KEYWORDS(|| ctx->ctx_res_w != RES_NONE)) {
3476 debug_printf_parse("done_pipe: adding new pipe: "
3477 "not_null:%d ctx->ctx_res_w:%d\n",
3478 not_null, ctx->ctx_res_w);
3480 ctx->pipe->next = new_p;
3482 /* RES_THEN, RES_DO etc are "sticky" -
3483 * they remain set for commands inside if/while.
3484 * This is used to control execution.
3485 * RES_FOR and RES_IN are NOT sticky (needed to support
3486 * cases where variable or value happens to match a keyword):
3488 #if ENABLE_HUSH_LOOPS
3489 if (ctx->ctx_res_w == RES_FOR
3490 || ctx->ctx_res_w == RES_IN)
3491 ctx->ctx_res_w = RES_NONE;
3493 #if ENABLE_HUSH_CASE
3494 if (ctx->ctx_res_w == RES_MATCH)
3495 ctx->ctx_res_w = RES_CASEI;
3497 ctx->command = NULL; /* trick done_command below */
3498 /* Create the memory for command, roughly:
3499 * ctx->pipe->cmds = new struct command;
3500 * ctx->command = &ctx->pipe->cmds[0];
3504 debug_printf_parse("done_pipe return\n");
3507 static void initialize_context(struct parse_context *ctx)
3509 memset(ctx, 0, sizeof(*ctx));
3510 ctx->pipe = ctx->list_head = new_pipe();
3511 /* Create the memory for command, roughly:
3512 * ctx->pipe->cmds = new struct command;
3513 * ctx->command = &ctx->pipe->cmds[0];
3519 /* If a reserved word is found and processed, parse context is modified
3520 * and 1 is returned.
3523 struct reserved_combo {
3526 unsigned char assignment_flag;
3530 FLAG_END = (1 << RES_NONE ),
3532 FLAG_IF = (1 << RES_IF ),
3533 FLAG_THEN = (1 << RES_THEN ),
3534 FLAG_ELIF = (1 << RES_ELIF ),
3535 FLAG_ELSE = (1 << RES_ELSE ),
3536 FLAG_FI = (1 << RES_FI ),
3538 #if ENABLE_HUSH_LOOPS
3539 FLAG_FOR = (1 << RES_FOR ),
3540 FLAG_WHILE = (1 << RES_WHILE),
3541 FLAG_UNTIL = (1 << RES_UNTIL),
3542 FLAG_DO = (1 << RES_DO ),
3543 FLAG_DONE = (1 << RES_DONE ),
3544 FLAG_IN = (1 << RES_IN ),
3546 #if ENABLE_HUSH_CASE
3547 FLAG_MATCH = (1 << RES_MATCH),
3548 FLAG_ESAC = (1 << RES_ESAC ),
3550 FLAG_START = (1 << RES_XXXX ),
3553 static const struct reserved_combo* match_reserved_word(o_string *word)
3555 /* Mostly a list of accepted follow-up reserved words.
3556 * FLAG_END means we are done with the sequence, and are ready
3557 * to turn the compound list into a command.
3558 * FLAG_START means the word must start a new compound list.
3560 static const struct reserved_combo reserved_list[] = {
3562 { "!", RES_NONE, NOT_ASSIGNMENT , 0 },
3563 { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START },
3564 { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
3565 { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN },
3566 { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI },
3567 { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
3569 #if ENABLE_HUSH_LOOPS
3570 { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
3571 { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3572 { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START },
3573 { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
3574 { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE },
3575 { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
3577 #if ENABLE_HUSH_CASE
3578 { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
3579 { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
3582 const struct reserved_combo *r;
3584 for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
3585 if (strcmp(word->data, r->literal) == 0)
3590 static int reserved_word(o_string *word, struct parse_context *ctx)
3592 #if ENABLE_HUSH_CASE
3593 static const struct reserved_combo reserved_match = {
3594 "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
3597 const struct reserved_combo *r;
3599 r = match_reserved_word(word);
3603 debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
3604 #if ENABLE_HUSH_CASE
3605 if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE)
3606 /* "case word IN ..." - IN part starts first match part */
3607 r = &reserved_match;
3610 if (r->flag == 0) { /* '!' */
3611 if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
3612 syntax("! ! command");
3613 IF_HAS_KEYWORDS(ctx->ctx_res_w = RES_SNTX;)
3615 ctx->ctx_inverted = 1;
3618 if (r->flag & FLAG_START) {
3619 struct parse_context *old;
3620 old = xmalloc(sizeof(*old));
3621 debug_printf_parse("push stack %p\n", old);
3622 *old = *ctx; /* physical copy */
3623 initialize_context(ctx);
3625 } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
3627 ctx->ctx_res_w = RES_SNTX;
3630 ctx->ctx_res_w = r->res;
3631 ctx->old_flag = r->flag;
3632 if (ctx->old_flag & FLAG_END) {
3633 struct parse_context *old;
3634 done_pipe(ctx, PIPE_SEQ);
3635 debug_printf_parse("pop stack %p\n", ctx->stack);
3637 old->command->group = ctx->list_head;
3638 old->command->grp_type = GRP_NORMAL;
3640 o_addstr(&old->as_string, ctx->as_string.data);
3641 o_free_unsafe(&ctx->as_string);
3642 old->command->group_as_string = xstrdup(old->as_string.data);
3643 debug_printf_parse("pop, remembering as:'%s'\n",
3644 old->command->group_as_string);
3646 *ctx = *old; /* physical copy */
3649 word->o_assignment = r->assignment_flag;
3654 /* Word is complete, look at it and update parsing context.
3655 * Normal return is 0. Syntax errors return 1.
3656 * Note: on return, word is reset, but not o_free'd!
3658 static int done_word(o_string *word, struct parse_context *ctx)
3660 struct command *command = ctx->command;
3662 debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
3663 if (word->length == 0 && word->nonnull == 0) {
3664 debug_printf_parse("done_word return 0: true null, ignored\n");
3667 /* If this word wasn't an assignment, next ones definitely
3668 * can't be assignments. Even if they look like ones. */
3669 if (word->o_assignment != DEFINITELY_ASSIGNMENT
3670 && word->o_assignment != WORD_IS_KEYWORD
3672 word->o_assignment = NOT_ASSIGNMENT;
3674 if (word->o_assignment == DEFINITELY_ASSIGNMENT)
3675 command->assignment_cnt++;
3676 word->o_assignment = MAYBE_ASSIGNMENT;
3679 if (ctx->pending_redirect) {
3680 /* We do not glob in e.g. >*.tmp case. bash seems to glob here
3681 * only if run as "bash", not "sh" */
3682 ctx->pending_redirect->rd_filename = xstrdup(word->data);
3683 word->o_assignment = NOT_ASSIGNMENT;
3684 debug_printf("word stored in rd_filename: '%s'\n", word->data);
3686 /* "{ echo foo; } echo bar" - bad */
3687 /* NB: bash allows e.g.:
3688 * if true; then { echo foo; } fi
3689 * while if false; then false; fi do break; done
3691 if (command->group) {
3693 debug_printf_parse("done_word return 1: syntax error, "
3694 "groups and arglists don't mix\n");
3698 #if ENABLE_HUSH_CASE
3699 if (ctx->ctx_dsemicolon
3700 && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
3702 /* already done when ctx_dsemicolon was set to 1: */
3703 /* ctx->ctx_res_w = RES_MATCH; */
3704 ctx->ctx_dsemicolon = 0;
3707 if (!command->argv /* if it's the first word... */
3708 #if ENABLE_HUSH_LOOPS
3709 && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
3710 && ctx->ctx_res_w != RES_IN
3713 debug_printf_parse(": checking '%s' for reserved-ness\n", word->data);
3714 if (reserved_word(word, ctx)) {
3716 debug_printf_parse("done_word return %d\n",
3717 (ctx->ctx_res_w == RES_SNTX));
3718 return (ctx->ctx_res_w == RES_SNTX);
3722 if (word->nonnull /* word had "xx" or 'xx' at least as part of it. */
3723 /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
3724 && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
3725 /* (otherwise it's known to be not empty and is already safe) */
3727 /* exclude "$@" - it can expand to no word despite "" */
3728 char *p = word->data;
3729 while (p[0] == SPECIAL_VAR_SYMBOL
3730 && (p[1] & 0x7f) == '@'
3731 && p[2] == SPECIAL_VAR_SYMBOL
3735 if (p == word->data || p[0] != '\0') {
3736 /* saw no "$@", or not only "$@" but some
3737 * real text is there too */
3738 /* insert "empty variable" reference, this makes
3739 * e.g. "", $empty"" etc to not disappear */
3740 o_addchr(word, SPECIAL_VAR_SYMBOL);
3741 o_addchr(word, SPECIAL_VAR_SYMBOL);
3744 command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
3745 debug_print_strings("word appended to argv", command->argv);
3749 ctx->pending_redirect = NULL;
3751 #if ENABLE_HUSH_LOOPS
3752 /* Force FOR to have just one word (variable name) */
3753 /* NB: basically, this makes hush see "for v in ..." syntax as if
3754 * as it is "for v; in ...". FOR and IN become two pipe structs
3756 if (ctx->ctx_res_w == RES_FOR) {
3757 //TODO: check that command->argv[0] is a valid variable name!
3758 done_pipe(ctx, PIPE_SEQ);
3761 #if ENABLE_HUSH_CASE
3762 /* Force CASE to have just one word */
3763 if (ctx->ctx_res_w == RES_CASE) {
3764 done_pipe(ctx, PIPE_SEQ);
3767 debug_printf_parse("done_word return 0\n");
3771 /* If a redirect is immediately preceded by a number, that number is
3772 * supposed to tell which file descriptor to redirect. This routine
3773 * looks for such preceding numbers. In an ideal world this routine
3774 * needs to handle all the following classes of redirects...
3775 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
3776 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
3777 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
3778 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
3779 * A -1 output from this program means no valid number was found, so the
3780 * caller should use the appropriate default for this redirection.
3782 static int redirect_opt_num(o_string *o)
3788 for (num = 0; num < o->length; num++) {
3789 if (!isdigit(o->data[num])) {
3793 num = atoi(o->data);
3799 #define parse_stream(pstring, input, end_trigger) \
3800 parse_stream(input, end_trigger)
3802 static struct pipe *parse_stream(char **pstring,
3803 struct in_str *input,
3805 static void parse_and_run_string(const char *s);
3807 #if ENABLE_HUSH_TICK
3808 static FILE *generate_stream_from_string(const char *s)
3811 int pid, channel[2];
3814 pid = BB_MMU ? fork() : vfork();
3816 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
3818 if (pid == 0) { /* child */
3819 /* Process substitution is not considered to be usual
3820 * 'command execution'.
3821 * SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
3828 if (ENABLE_HUSH_JOB)
3829 die_sleep = 0; /* let nofork's xfuncs die */
3830 close(channel[0]); /* NB: close _first_, then move fd! */
3831 xmove_fd(channel[1], 1);
3832 /* Prevent it from trying to handle ctrl-z etc */
3833 USE_HUSH_JOB(G.run_list_level = 1;)
3835 parse_and_run_string(s);
3836 _exit(G.last_return_code);
3838 /* We re-execute after vfork on NOMMU. This makes this script safe:
3839 * yes "0123456789012345678901234567890" | dd bs=32 count=64k >TESTFILE
3840 * huge=`cat TESTFILE` # was blocking here forever
3843 re_execute_shell(s);
3849 pf = fdopen(channel[0], "r");
3853 /* Return code is exit status of the process that is run. */
3854 static int process_command_subs(o_string *dest, const char *s)
3857 struct in_str pipe_str;
3860 pf = generate_stream_from_string(s);
3863 close_on_exec_on(fileno(pf));
3865 /* Now send results of command back into original context */
3866 setup_file_in_str(&pipe_str, pf);
3868 while ((ch = i_getch(&pipe_str)) != EOF) {
3874 o_addchr(dest, '\n');
3877 o_addQchr(dest, ch);
3880 debug_printf("done reading from pipe, pclose()ing\n");
3881 /* Note: we got EOF, and we just close the read end of the pipe.
3882 * We do not wait for the `cmd` child to terminate. bash and ash do.
3884 * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec
3885 * `false`; echo $? - bash outputs "1"
3888 debug_printf("closed FILE from child. return 0\n");
3893 static int parse_group(o_string *dest, struct parse_context *ctx,
3894 struct in_str *input, int ch)
3896 /* dest contains characters seen prior to ( or {.
3897 * Typically it's empty, but for function defs,
3898 * it contains function name (without '()'). */
3899 struct pipe *pipe_list;
3901 struct command *command = ctx->command;
3903 debug_printf_parse("parse_group entered\n");
3904 #if ENABLE_HUSH_FUNCTIONS
3905 if (ch == 'F') { /* function definition? */
3906 bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
3907 //command->fname = dest->data;
3908 command->grp_type = GRP_FUNCTION;
3909 //TODO: review every o_reset() location... do they handle all o_string fields correctly?
3910 memset(dest, 0, sizeof(*dest));
3913 if (command->argv /* word [word](... */
3914 || dest->length /* word(... */
3915 || dest->nonnull /* ""(... */
3918 debug_printf_parse("parse_group return 1: "
3919 "syntax error, groups and arglists don't mix\n");
3925 command->grp_type = GRP_SUBSHELL;
3929 char *as_string = NULL;
3931 pipe_list = parse_stream(&as_string, input, endch);
3934 o_addstr(&ctx->as_string, as_string);
3936 /* empty ()/{} or parse error? */
3937 if (!pipe_list || pipe_list == ERR_PTR) {
3942 debug_printf_parse("parse_group return 1: "
3943 "parse_stream returned %p\n", pipe_list);
3946 command->group = pipe_list;
3948 as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
3949 command->group_as_string = as_string;
3950 debug_printf_parse("end of group, remembering as:'%s'\n",
3951 command->group_as_string);
3954 debug_printf_parse("parse_group return 0\n");
3956 /* command remains "open", available for possible redirects */
3959 #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT
3960 /* Subroutines for copying $(...) and `...` things */
3961 static void add_till_backquote(o_string *dest, struct in_str *input);
3963 static void add_till_single_quote(o_string *dest, struct in_str *input)
3966 int ch = i_getch(input);
3974 /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
3975 static void add_till_double_quote(o_string *dest, struct in_str *input)
3978 int ch = i_getch(input);
3981 if (ch == '\\') { /* \x. Copy both chars. */
3983 ch = i_getch(input);
3989 add_till_backquote(dest, input);
3993 //if (ch == '$') ...
3996 /* Process `cmd` - copy contents until "`" is seen. Complicated by
3998 * "Within the backquoted style of command substitution, backslash
3999 * shall retain its literal meaning, except when followed by: '$', '`', or '\'.
4000 * The search for the matching backquote shall be satisfied by the first
4001 * backquote found without a preceding backslash; during this search,
4002 * if a non-escaped backquote is encountered within a shell comment,
4003 * a here-document, an embedded command substitution of the $(command)
4004 * form, or a quoted string, undefined results occur. A single-quoted
4005 * or double-quoted string that begins, but does not end, within the
4006 * "`...`" sequence produces undefined results."
4008 * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
4010 static void add_till_backquote(o_string *dest, struct in_str *input)
4013 int ch = i_getch(input);
4016 if (ch == '\\') { /* \x. Copy both chars unless it is \` */
4017 int ch2 = i_getch(input);
4018 if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
4027 /* Process $(cmd) - copy contents until ")" is seen. Complicated by
4028 * quoting and nested ()s.
4029 * "With the $(command) style of command substitution, all characters
4030 * following the open parenthesis to the matching closing parenthesis
4031 * constitute the command. Any valid shell script can be used for command,
4032 * except a script consisting solely of redirections which produces
4033 * unspecified results."
4035 * echo $(echo '(TEST)' BEST) (TEST) BEST
4036 * echo $(echo 'TEST)' BEST) TEST) BEST
4037 * echo $(echo \(\(TEST\) BEST) ((TEST) BEST
4039 static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
4043 int ch = i_getch(input);
4052 if (i_peek(input) == ')') {
4060 add_till_single_quote(dest, input);
4065 add_till_double_quote(dest, input);
4069 if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */
4070 ch = i_getch(input);
4078 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
4080 /* Return code: 0 for OK, 1 for syntax error */
4082 #define handle_dollar(ctx, dest, input) \
4083 handle_dollar(dest, input)
4085 static int handle_dollar(struct parse_context *ctx,
4087 struct in_str *input)
4090 int ch = i_peek(input); /* first character after the $ */
4091 unsigned char quote_mask = dest->o_escape ? 0x80 : 0;
4093 debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
4095 ch = i_getch(input);
4097 o_addchr(&ctx->as_string, ch);
4100 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4102 debug_printf_parse(": '%c'\n", ch);
4103 o_addchr(dest, ch | quote_mask);
4106 if (!isalnum(ch) && ch != '_')
4108 ch = i_getch(input);
4110 o_addchr(&ctx->as_string, ch);
4113 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4114 } else if (isdigit(ch)) {
4116 ch = i_getch(input);
4118 o_addchr(&ctx->as_string, ch);
4120 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4121 debug_printf_parse(": '%c'\n", ch);
4122 o_addchr(dest, ch | quote_mask);
4123 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4124 } else switch (ch) {
4126 case '!': /* last bg pid */
4127 case '?': /* last exit code */
4128 case '#': /* number of args */
4129 case '*': /* args */
4130 case '@': /* args */
4131 goto make_one_char_var;
4133 bool first_char, all_digits;
4135 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4136 ch = i_getch(input);
4138 o_addchr(&ctx->as_string, ch);
4140 /* XXX maybe someone will try to escape the '}' */
4145 ch = i_getch(input);
4147 o_addchr(&ctx->as_string, ch);
4154 /* ${#var}: length of var contents */
4156 else if (isdigit(ch)) {
4163 && ( (all_digits && !isdigit(ch))
4164 || (!all_digits && !isalnum(ch) && ch != '_')
4167 /* handle parameter expansions
4168 * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
4173 case ':': /* null modifier */
4174 if (expansion == 0) {
4175 debug_printf_parse(": null modifier\n");
4180 #if 0 /* not implemented yet :( */
4181 case '#': /* remove prefix */
4182 case '%': /* remove suffix */
4183 if (expansion == 0) {
4184 debug_printf_parse(": remove suffix/prefix\n");
4190 case '-': /* default value */
4191 case '=': /* assign default */
4192 case '+': /* alternative */
4193 case '?': /* error indicate */
4194 debug_printf_parse(": parameter expansion\n");
4199 syntax("unterminated ${name}");
4200 debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
4205 debug_printf_parse(": '%c'\n", ch);
4206 o_addchr(dest, ch | quote_mask);
4210 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4214 ch = i_getch(input);
4216 o_addchr(&ctx->as_string, ch);
4218 #if ENABLE_SH_MATH_SUPPORT
4219 if (i_peek(input) == '(') {
4220 ch = i_getch(input);
4222 o_addchr(&ctx->as_string, ch);
4224 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4225 o_addchr(dest, /*quote_mask |*/ '+');
4226 add_till_closing_paren(dest, input, true);
4227 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4231 #if ENABLE_HUSH_TICK
4232 //int pos = dest->length;
4233 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4234 o_addchr(dest, quote_mask | '`');
4235 add_till_closing_paren(dest, input, false);
4236 //debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos);
4237 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4242 ch = i_getch(input);
4244 o_addchr(&ctx->as_string, ch);
4247 if (isalnum(ch)) { /* it's $_name or $_123 */
4253 /* $_ Shell or shell script name; or last cmd name */
4254 /* $- Option flags set by set builtin or shell options (-i etc) */
4256 o_addQchr(dest, '$');
4258 debug_printf_parse("handle_dollar return 0\n");
4263 #define parse_stream_dquoted(ctx, dest, input, dquote_end) \
4264 parse_stream_dquoted(dest, input, dquote_end)
4266 static int parse_stream_dquoted(struct parse_context *ctx,
4268 struct in_str *input,
4275 ch = i_getch(input);
4277 if (ctx && ch != EOF)
4278 o_addchr(&ctx->as_string, ch);
4280 if (ch == dquote_end) { /* may be only '"' or EOF */
4282 if (dest->o_assignment == NOT_ASSIGNMENT)
4283 dest->o_escape ^= 1;
4284 debug_printf_parse("parse_stream_dquoted return 0\n");
4288 syntax("unterminated \"");
4289 debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n");
4294 next = i_peek(input);
4296 debug_printf_parse(": ch=%c (%d) m=%d escape=%d\n",
4297 ch, ch, m, dest->o_escape);
4301 debug_printf_parse("parse_stream_dquoted return 1: \\<eof>\n");
4305 * "The backslash retains its special meaning [in "..."]
4306 * only when followed by one of the following characters:
4307 * $, `, ", \, or <newline>. A double quote may be quoted
4308 * within double quotes by preceding it with a backslash.
4309 * If enabled, history expansion will be performed unless
4310 * an ! appearing in double quotes is escaped using
4311 * a backslash. The backslash preceding the ! is not removed."
4313 if (strchr("$`\"\\", next) != NULL) {
4314 o_addqchr(dest, i_getch(input));
4316 o_addqchr(dest, '\\');
4321 if (handle_dollar(ctx, dest, input) != 0) {
4322 debug_printf_parse("parse_stream_dquoted return 1: "
4323 "handle_dollar returned non-0\n");
4328 #if ENABLE_HUSH_TICK
4330 //int pos = dest->length;
4331 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4332 o_addchr(dest, 0x80 | '`');
4333 add_till_backquote(dest, input);
4334 o_addchr(dest, SPECIAL_VAR_SYMBOL);
4335 //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
4339 o_addQchr(dest, ch);
4341 && (dest->o_assignment == MAYBE_ASSIGNMENT
4342 || dest->o_assignment == WORD_IS_KEYWORD)
4343 && is_assignment(dest->data)
4345 dest->o_assignment = DEFINITELY_ASSIGNMENT;
4351 * Scan input until EOF or end_trigger char.
4352 * Return a list of pipes to execute, or NULL on EOF
4353 * or if end_trigger character is met.
4354 * On syntax error, exit is shell is not interactive,
4355 * reset parsing machinery and start parsing anew,
4356 * or return ERR_PTR.
4358 static struct pipe *parse_stream(char **pstring,
4359 struct in_str *input,
4362 struct parse_context ctx;
4363 o_string dest = NULL_O_STRING;
4366 /* Double-quote state is handled in the state variable is_in_dquote.
4367 * A single-quote triggers a bypass of the main loop until its mate is
4368 * found. When recursing, quote state is passed in via dest->o_escape.
4370 debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
4371 end_trigger ? : 'X');
4373 G.ifs = get_local_var_value("IFS");
4378 #if ENABLE_HUSH_INTERACTIVE
4379 input->promptmode = 0; /* PS1 */
4381 /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */
4382 initialize_context(&ctx);
4386 const char *is_special;
4390 redir_type redir_style;
4393 if (parse_stream_dquoted(&ctx, &dest, input, '"')) {
4396 /* We reached closing '"' */
4399 ch = i_getch(input);
4400 debug_printf_parse(": ch=%c (%d) escape=%d\n",
4401 ch, ch, dest.o_escape);
4404 if (done_word(&dest, &ctx)) {
4408 done_pipe(&ctx, PIPE_SEQ);
4410 /* If we got nothing... */
4411 // TODO: test script consisting of just "&"
4412 if (pi->num_cmds == 0
4413 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
4415 free_pipe_list(pi, 0);
4418 debug_printf_parse("parse_stream return %p\n", pi);
4420 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4422 *pstring = ctx.as_string.data;
4424 o_free_unsafe(&ctx.as_string);
4429 o_addchr(&ctx.as_string, ch);
4431 is_ifs = strchr(G.ifs, ch);
4432 is_special = strchr("<>;&|(){}#'" /* special outside of "str" */
4433 "\\$\"" USE_HUSH_TICK("`") /* always special */
4436 if (!is_special && !is_ifs) { /* ordinary char */
4437 o_addQchr(&dest, ch);
4438 if ((dest.o_assignment == MAYBE_ASSIGNMENT
4439 || dest.o_assignment == WORD_IS_KEYWORD)
4441 && is_assignment(dest.data)
4443 dest.o_assignment = DEFINITELY_ASSIGNMENT;
4449 if (done_word(&dest, &ctx)) {
4453 #if ENABLE_HUSH_CASE
4454 /* "case ... in <newline> word) ..." -
4455 * newlines are ignored (but ';' wouldn't be) */
4456 if (ctx.command->argv == NULL
4457 && ctx.ctx_res_w == RES_MATCH
4462 /* Treat newline as a command separator. */
4463 done_pipe(&ctx, PIPE_SEQ);
4464 dest.o_assignment = MAYBE_ASSIGNMENT;
4466 /* note: if (is_ifs) continue;
4467 * will still trigger for us */
4470 if (end_trigger && end_trigger == ch) {
4471 //TODO: disallow "{ cmd }" without semicolon
4472 if (done_word(&dest, &ctx)) {
4475 done_pipe(&ctx, PIPE_SEQ);
4476 dest.o_assignment = MAYBE_ASSIGNMENT;
4477 /* Do we sit outside of any if's, loops or case's? */
4479 IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
4481 debug_printf_parse("parse_stream return %p: "
4482 "end_trigger char found\n",
4486 debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
4488 *pstring = ctx.as_string.data;
4490 o_free_unsafe(&ctx.as_string);
4492 return ctx.list_head;
4498 if (dest.o_assignment == MAYBE_ASSIGNMENT) {
4499 /* ch is a special char and thus this word
4500 * cannot be an assignment */
4501 dest.o_assignment = NOT_ASSIGNMENT;
4506 next = i_peek(input);
4511 if (dest.length == 0) {
4514 if (ch == EOF || ch == '\n')
4517 /* note: we do not add it to &ctx.as_string */
4520 //TODO: go back one char?
4521 o_addchr(&ctx.as_string, '\n');
4524 o_addQchr(&dest, ch);
4532 o_addchr(&dest, '\\');
4533 ch = i_getch(input);
4534 o_addchr(&dest, ch);
4536 o_addchr(&ctx.as_string, ch);
4541 if (handle_dollar(&ctx, &dest, input) != 0) {
4542 debug_printf_parse("parse_stream parse error: "
4543 "handle_dollar returned non-0\n");
4550 ch = i_getch(input);
4552 syntax("unterminated '");
4556 o_addchr(&ctx.as_string, ch);
4560 if (dest.o_assignment == NOT_ASSIGNMENT)
4561 o_addqchr(&dest, ch);
4563 o_addchr(&dest, ch);
4568 is_in_dquote ^= 1; /* invert */
4569 if (dest.o_assignment == NOT_ASSIGNMENT)
4572 #if ENABLE_HUSH_TICK
4574 //int pos = dest.length;
4575 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4576 o_addchr(&dest, '`');
4577 add_till_backquote(&dest, input);
4578 o_addchr(&dest, SPECIAL_VAR_SYMBOL);
4579 //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos);
4584 redir_fd = redirect_opt_num(&dest);
4585 if (done_word(&dest, &ctx)) {
4588 redir_style = REDIRECT_OVERWRITE;
4590 redir_style = REDIRECT_APPEND;
4591 ch = i_getch(input);
4593 o_addchr(&ctx.as_string, ch);
4597 else if (next == '(') {
4598 syntax(">(process) not supported");
4602 setup_redirect(&ctx, redir_fd, redir_style, input);
4605 redir_fd = redirect_opt_num(&dest);
4606 if (done_word(&dest, &ctx)) {
4609 redir_style = REDIRECT_INPUT;
4611 redir_style = REDIRECT_HEREIS;
4612 ch = i_getch(input);
4614 o_addchr(&ctx.as_string, ch);
4616 } else if (next == '>') {
4617 redir_style = REDIRECT_IO;
4618 ch = i_getch(input);
4620 o_addchr(&ctx.as_string, ch);
4624 else if (next == '(') {
4625 syntax("<(process) not supported");
4629 setup_redirect(&ctx, redir_fd, redir_style, input);
4632 #if ENABLE_HUSH_CASE
4635 if (done_word(&dest, &ctx)) {
4638 done_pipe(&ctx, PIPE_SEQ);
4639 #if ENABLE_HUSH_CASE
4640 /* Eat multiple semicolons, detect
4641 * whether it means something special */
4646 ch = i_getch(input);
4648 o_addchr(&ctx.as_string, ch);
4650 if (ctx.ctx_res_w == RES_CASEI) {
4651 ctx.ctx_dsemicolon = 1;
4652 ctx.ctx_res_w = RES_MATCH;
4658 /* We just finished a cmd. New one may start
4659 * with an assignment */
4660 dest.o_assignment = MAYBE_ASSIGNMENT;
4663 if (done_word(&dest, &ctx)) {
4667 ch = i_getch(input);
4669 o_addchr(&ctx.as_string, ch);
4671 done_pipe(&ctx, PIPE_AND);
4673 done_pipe(&ctx, PIPE_BG);
4677 if (done_word(&dest, &ctx)) {
4680 #if ENABLE_HUSH_CASE
4681 if (ctx.ctx_res_w == RES_MATCH)
4682 break; /* we are in case's "word | word)" */
4684 if (next == '|') { /* || */
4685 ch = i_getch(input);
4687 o_addchr(&ctx.as_string, ch);
4689 done_pipe(&ctx, PIPE_OR);
4691 /* we could pick up a file descriptor choice here
4692 * with redirect_opt_num(), but bash doesn't do it.
4693 * "echo foo 2| cat" yields "foo 2". */
4698 #if ENABLE_HUSH_CASE
4699 /* "case... in [(]word)..." - skip '(' */
4700 if (ctx.ctx_res_w == RES_MATCH
4701 && ctx.command->argv == NULL /* not (word|(... */
4702 && dest.length == 0 /* not word(... */
4703 && dest.nonnull == 0 /* not ""(... */
4708 #if ENABLE_HUSH_FUNCTIONS
4709 if (dest.length != 0 /* not just () but word() */
4710 && dest.nonnull == 0 /* not a"b"c() */
4711 && ctx.command->argv == NULL /* it's the first word */
4712 //TODO: "func ( ) {...}" - note spaces - is valid format too in bash
4713 && i_peek(input) == ')'
4714 && !match_reserved_word(&dest)
4716 bb_error_msg("seems like a function definition");
4718 //if !BB_MMU o_addchr(&ctx.as_string...
4720 //TODO: do it properly.
4721 ch = i_getch(input);
4722 } while (ch == ' ' || ch == '\n');
4724 syntax("was expecting {");
4727 ch = 'F'; /* magic value */
4731 if (parse_group(&dest, &ctx, input, ch) != 0) {
4736 #if ENABLE_HUSH_CASE
4737 if (ctx.ctx_res_w == RES_MATCH)
4741 /* proper use of this character is caught by end_trigger:
4742 * if we see {, we call parse_group(..., end_trigger='}')
4743 * and it will match } earlier (not here). */
4744 syntax("unexpected } or )");
4748 bb_error_msg_and_die("BUG: unexpected %c\n", ch);
4754 struct parse_context *pctx;
4755 IF_HAS_KEYWORDS(struct parse_context *p2;)
4757 /* Clean up allocated tree.
4758 * Samples for finding leaks on syntax error recovery path.
4759 * Run them from interactive shell, watch pmap `pidof hush`.
4760 * while if false; then false; fi do break; done
4762 * while if false; then false; fi; do break; fi
4766 /* Update pipe/command counts,
4767 * otherwise freeing may miss some */
4768 done_pipe(pctx, PIPE_SEQ);
4769 debug_printf_clean("freeing list %p from ctx %p\n",
4770 pctx->list_head, pctx);
4771 debug_print_tree(pctx->list_head, 0);
4772 free_pipe_list(pctx->list_head, 0);
4773 debug_printf_clean("freed list %p\n", pctx->list_head);
4775 o_free_unsafe(&pctx->as_string);
4777 IF_HAS_KEYWORDS(p2 = pctx->stack;)
4781 IF_HAS_KEYWORDS(pctx = p2;)
4782 } while (HAS_KEYWORDS && pctx);
4783 /* Free text, clear all dest fields */
4785 /* If we are not in top-level parse, we return,
4786 * our caller will propagate error.
4788 if (end_trigger != ';') {
4795 /* Discard cached input, force prompt */
4797 USE_HUSH_INTERACTIVE(input->promptme = 1;)
4802 /* Executing from string: eval, sh -c '...'
4803 * or from file: /etc/profile, . file, sh <script>, sh (intereactive)
4804 * end_trigger controls how often we stop parsing
4805 * NUL: parse all, execute, return
4806 * ';': parse till ';' or newline, execute, repeat till EOF
4808 static void parse_and_run_stream(struct in_str *inp, int end_trigger)
4811 struct pipe *pipe_list;
4813 pipe_list = parse_stream(NULL, inp, end_trigger);
4814 if (!pipe_list) /* EOF */
4816 debug_print_tree(pipe_list, 0);
4817 debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
4818 run_and_free_list(pipe_list);
4822 static void parse_and_run_string(const char *s)
4824 struct in_str input;
4825 setup_string_in_str(&input, s);
4826 parse_and_run_stream(&input, '\0');
4829 static void parse_and_run_file(FILE *f)
4831 struct in_str input;
4832 setup_file_in_str(&input, f);
4833 parse_and_run_stream(&input, ';');
4837 /* Make sure we have a controlling tty. If we get started under a job
4838 * aware app (like bash for example), make sure we are now in charge so
4839 * we don't fight over who gets the foreground */
4840 static void setup_job_control(void)
4844 shell_pgrp = getpgrp();
4846 /* If we were ran as 'hush &',
4847 * sleep until we are in the foreground. */
4848 while (tcgetpgrp(G_interactive_fd) != shell_pgrp) {
4849 /* Send TTIN to ourself (should stop us) */
4850 kill(- shell_pgrp, SIGTTIN);
4851 shell_pgrp = getpgrp();
4854 /* We _must_ restore tty pgrp on fatal signals */
4855 set_fatal_signals_to_sigexit();
4857 /* Put ourselves in our own process group. */
4858 bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
4859 /* Grab control of the terminal. */
4860 tcsetpgrp(G_interactive_fd, getpid());
4864 static int set_mode(const char cstate, const char mode)
4866 int state = (cstate == '-' ? 1 : 0);
4868 case 'n': G.fake_mode = state; break;
4869 case 'x': /*G.debug_mode = state;*/ break;
4870 default: return EXIT_FAILURE;
4872 return EXIT_SUCCESS;
4875 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
4876 int hush_main(int argc, char **argv)
4878 static const struct variable const_shell_ver = {
4880 .varstr = (char*)hush_version_str,
4881 .max_len = 1, /* 0 can provoke free(name) */
4889 struct variable *cur_var;
4893 G.root_pid = getpid();
4895 /* Deal with HUSH_VERSION */
4896 G.shell_ver = const_shell_ver; /* copying struct here */
4897 G.top_var = &G.shell_ver;
4898 debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
4899 unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
4900 /* Initialize our shell local variables with the values
4901 * currently living in the environment */
4902 cur_var = G.top_var;
4905 char *value = strchr(*e, '=');
4906 if (value) { /* paranoia */
4907 cur_var->next = xzalloc(sizeof(*cur_var));
4908 cur_var = cur_var->next;
4909 cur_var->varstr = *e;
4910 cur_var->max_len = strlen(*e);
4911 cur_var->flg_export = 1;
4915 debug_printf_env("putenv '%s'\n", hush_version_str);
4916 putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
4918 #if ENABLE_FEATURE_EDITING
4919 G.line_input_state = new_line_input_t(FOR_SHELL);
4921 /* XXX what should these be while sourcing /etc/profile? */
4922 G.global_argc = argc;
4923 G.global_argv = argv;
4924 /* Initialize some more globals to non-zero values */
4926 #if ENABLE_HUSH_INTERACTIVE
4927 if (ENABLE_FEATURE_EDITING)
4928 cmdedit_set_initial_prompt();
4932 if (EXIT_SUCCESS) /* otherwise is already done */
4933 G.last_return_code = EXIT_SUCCESS;
4935 if (argv[0] && argv[0][0] == '-') {
4936 debug_printf("sourcing /etc/profile\n");
4937 input = fopen_for_read("/etc/profile");
4938 if (input != NULL) {
4939 close_on_exec_on(fileno(input));
4940 parse_and_run_file(input);
4946 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
4947 while ((opt = getopt(argc, argv, "c:xins")) > 0) {
4950 G.global_argv = argv + optind;
4951 if (!argv[optind]) {
4952 /* -c 'script' (no params): prevent empty $0 */
4953 *--G.global_argv = argv[0];
4955 } /* else -c 'script' PAR0 PAR1: $0 is PAR0 */
4956 G.global_argc = argc - optind;
4957 parse_and_run_string(optarg);
4960 /* Well, we cannot just declare interactiveness,
4961 * we have to have some stuff (ctty, etc) */
4962 /* G_interactive_fd++; */
4965 /* "-s" means "read from stdin", but this is how we always
4966 * operate, so simply do nothing here. */
4970 if (!set_mode('-', opt))
4974 fprintf(stderr, "Usage: sh [FILE]...\n"
4975 " or: sh -c command [args]...\n\n");
4983 /* A shell is interactive if the '-i' flag was given, or if all of
4984 * the following conditions are met:
4986 * no arguments remaining or the -s flag given
4987 * standard input is a terminal
4988 * standard output is a terminal
4989 * Refer to Posix.2, the description of the 'sh' utility. */
4990 if (argv[optind] == NULL && input == stdin
4991 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
4993 G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
4994 debug_printf("saved_tty_pgrp=%d\n", G.saved_tty_pgrp);
4995 if (G.saved_tty_pgrp >= 0) {
4996 /* try to dup to high fd#, >= 255 */
4997 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
4998 if (G_interactive_fd < 0) {
4999 /* try to dup to any fd */
5000 G_interactive_fd = dup(STDIN_FILENO);
5001 if (G_interactive_fd < 0)
5003 G_interactive_fd = 0;
5005 // TODO: track & disallow any attempts of user
5006 // to (inadvertently) close/redirect it
5009 init_signal_mask(); /* note: ensures SIGCHLD is not masked */
5010 debug_printf("interactive_fd=%d\n", G_interactive_fd);
5011 if (G_interactive_fd) {
5012 fcntl(G_interactive_fd, F_SETFD, FD_CLOEXEC);
5013 /* Looks like they want an interactive shell */
5014 setup_job_control();
5015 /* -1 is special - makes xfuncs longjmp, not exit
5016 * (we reset die_sleep = 0 whereever we [v]fork) */
5018 if (setjmp(die_jmp)) {
5019 /* xfunc has failed! die die die */
5020 hush_exit(xfunc_error_retval);
5023 #elif ENABLE_HUSH_INTERACTIVE
5024 /* no job control compiled, only prompt/line editing */
5025 if (argv[optind] == NULL && input == stdin
5026 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
5028 G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
5029 if (G_interactive_fd < 0) {
5030 /* try to dup to any fd */
5031 G_interactive_fd = dup(STDIN_FILENO);
5032 if (G_interactive_fd < 0)
5034 G_interactive_fd = 0;
5036 if (G_interactive_fd) {
5037 fcntl(G_interactive_fd, F_SETFD, FD_CLOEXEC);
5040 init_signal_mask(); /* note: ensures SIGCHLD is not masked */
5044 /* POSIX allows shell to re-enable SIGCHLD
5045 * even if it was SIG_IGN on entry */
5046 // G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
5047 signal(SIGCHLD, SIG_DFL); // SIGCHLD_handler);
5049 #if ENABLE_HUSH_INTERACTIVE && !ENABLE_FEATURE_SH_EXTRA_QUIET
5050 if (G_interactive_fd) {
5051 printf("\n\n%s hush - the humble shell v"HUSH_VER_STR"\n", bb_banner);
5052 printf("Enter 'help' for a list of built-in commands.\n\n");
5056 if (argv[optind] == NULL) {
5057 parse_and_run_file(stdin);
5059 debug_printf("\nrunning script '%s'\n", argv[optind]);
5060 G.global_argv = argv + optind;
5061 G.global_argc = argc - optind;
5062 input = xfopen_for_read(argv[optind]);
5063 fcntl(fileno(input), F_SETFD, FD_CLOEXEC);
5064 parse_and_run_file(input);
5069 #if ENABLE_FEATURE_CLEAN_UP
5071 if (G.cwd != bb_msg_unknown)
5073 cur_var = G.top_var->next;
5075 struct variable *tmp = cur_var;
5076 if (!cur_var->max_len)
5077 free(cur_var->varstr);
5078 cur_var = cur_var->next;
5082 hush_exit(G.last_return_code);
5087 int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
5088 int lash_main(int argc, char **argv)
5090 //bb_error_msg("lash is deprecated, please use hush instead");
5091 return hush_main(argc, argv);
5099 static int builtin_trap(char **argv)
5106 G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
5109 /* No args: print all trapped. This isn't 100% correct as we should
5110 * be escaping the cmd so that it can be pasted back in ...
5112 for (i = 0; i < NSIG; ++i)
5114 printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
5115 return EXIT_SUCCESS;
5120 /* if first arg is decimal: reset all specified */
5121 sig = bb_strtou(*++argv, NULL, 10);
5127 sig = get_signum(*argv++);
5128 if (sig < 0 || sig >= NSIG) {
5130 /* mimic bash message exactly */
5131 bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
5136 G.traps[sig] = xstrdup(new_cmd);
5138 debug_printf("trap: setting SIG%s (%i) to '%s'",
5139 get_signame(sig), sig, G.traps[sig]);
5141 /* There is no signal for 0 (EXIT) */
5146 sigaddset(&G.blocked_set, sig);
5148 /* there was a trap handler, we are removing it
5149 * (if sig has non-DFL handling,
5150 * we don't need to do anything) */
5151 if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
5153 sigdelset(&G.blocked_set, sig);
5155 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5160 /* first arg is "-": reset all specified to default */
5161 /* first arg is "": ignore all specified */
5162 /* everything else: execute first arg upon signal */
5164 bb_error_msg("trap: invalid arguments");
5165 return EXIT_FAILURE;
5167 if (LONE_DASH(*argv))
5175 static int builtin_true(char **argv UNUSED_PARAM)
5180 static int builtin_test(char **argv)
5187 return test_main(argc, argv - argc);
5190 static int builtin_echo(char **argv)
5197 return echo_main(argc, argv - argc);
5200 static int builtin_eval(char **argv)
5202 int rcode = EXIT_SUCCESS;
5205 char *str = expand_strvec_to_string(argv + 1);
5207 * eval "echo Hi; done" ("done" is syntax error):
5208 * "echo Hi" will not execute too.
5210 parse_and_run_string(str);
5212 rcode = G.last_return_code;
5217 static int builtin_cd(char **argv)
5220 if (argv[1] == NULL) {
5221 /* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
5222 * bash says "bash: cd: HOME not set" and does nothing (exitcode 1)
5224 newdir = getenv("HOME") ? : "/";
5227 if (chdir(newdir)) {
5228 printf("cd: %s: %s\n", newdir, strerror(errno));
5229 return EXIT_FAILURE;
5232 return EXIT_SUCCESS;
5235 static int builtin_exec(char **argv)
5237 if (argv[1] == NULL)
5238 return EXIT_SUCCESS; /* bash does this */
5243 // FIXME: if exec fails, bash does NOT exit! We do...
5244 pseudo_exec_argv(&dummy, argv + 1, 0, NULL);
5249 static int builtin_exit(char **argv)
5251 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
5252 //puts("exit"); /* bash does it */
5253 // TODO: warn if we have background jobs: "There are stopped jobs"
5254 // On second consecutive 'exit', exit anyway.
5255 if (argv[1] == NULL)
5256 hush_exit(G.last_return_code);
5257 /* mimic bash: exit 123abc == exit 255 + error msg */
5258 xfunc_error_retval = 255;
5259 /* bash: exit -2 == exit 254, no error msg */
5260 hush_exit(xatoi(argv[1]) & 0xff);
5263 static int builtin_export(char **argv)
5266 char *name = argv[1];
5270 // ash emits: export VAR='VAL'
5271 // bash: declare -x VAR="VAL"
5272 // (both also escape as needed (quotes, $, etc))
5277 return EXIT_SUCCESS;
5280 value = strchr(name, '=');
5282 /* They are exporting something without a =VALUE */
5283 struct variable *var;
5285 var = get_local_var(name);
5287 var->flg_export = 1;
5288 debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
5289 putenv(var->varstr);
5291 /* bash does not return an error when trying to export
5292 * an undefined variable. Do likewise. */
5293 return EXIT_SUCCESS;
5296 set_local_var(xstrdup(name), 1);
5297 return EXIT_SUCCESS;
5301 /* built-in 'fg' and 'bg' handler */
5302 static int builtin_fg_bg(char **argv)
5307 if (!G_interactive_fd)
5308 return EXIT_FAILURE;
5309 /* If they gave us no args, assume they want the last backgrounded task */
5311 for (pi = G.job_list; pi; pi = pi->next) {
5312 if (pi->jobid == G.last_jobid) {
5316 bb_error_msg("%s: no current job", argv[0]);
5317 return EXIT_FAILURE;
5319 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
5320 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
5321 return EXIT_FAILURE;
5323 for (pi = G.job_list; pi; pi = pi->next) {
5324 if (pi->jobid == jobnum) {
5328 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
5329 return EXIT_FAILURE;
5331 // TODO: bash prints a string representation
5332 // of job being foregrounded (like "sleep 1 | cat")
5333 if (argv[0][0] == 'f') {
5334 /* Put the job into the foreground. */
5335 tcsetpgrp(G_interactive_fd, pi->pgrp);
5338 /* Restart the processes in the job */
5339 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
5340 for (i = 0; i < pi->num_cmds; i++) {
5341 debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
5342 pi->cmds[i].is_stopped = 0;
5344 pi->stopped_cmds = 0;
5346 i = kill(- pi->pgrp, SIGCONT);
5348 if (errno == ESRCH) {
5349 delete_finished_bg_job(pi);
5350 return EXIT_SUCCESS;
5352 bb_perror_msg("kill (SIGCONT)");
5355 if (argv[0][0] == 'f') {
5357 return checkjobs_and_fg_shell(pi);
5359 return EXIT_SUCCESS;
5363 #if ENABLE_HUSH_HELP
5364 static int builtin_help(char **argv UNUSED_PARAM)
5366 const struct built_in_command *x;
5369 "Built-in commands:\n"
5370 "------------------\n");
5371 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
5372 printf("%s\t%s\n", x->cmd, x->descr);
5375 return EXIT_SUCCESS;
5380 static int builtin_jobs(char **argv UNUSED_PARAM)
5383 const char *status_string;
5385 for (job = G.job_list; job; job = job->next) {
5386 if (job->alive_cmds == job->stopped_cmds)
5387 status_string = "Stopped";
5389 status_string = "Running";
5391 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
5393 return EXIT_SUCCESS;
5397 static int builtin_pwd(char **argv UNUSED_PARAM)
5400 return EXIT_SUCCESS;
5403 static int builtin_read(char **argv)
5406 const char *name = argv[1] ? argv[1] : "REPLY";
5408 string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL);
5409 return set_local_var(string, 0);
5412 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
5413 * built-in 'set' handler
5415 * set [-abCefhmnuvx] [-o option] [argument...]
5416 * set [+abCefhmnuvx] [+o option] [argument...]
5417 * set -- [argument...]
5420 * Implementations shall support the options in both their hyphen and
5421 * plus-sign forms. These options can also be specified as options to sh.
5423 * Write out all variables and their values: set
5424 * Set $1, $2, and $3 and set "$#" to 3: set c a b
5425 * Turn on the -x and -v options: set -xv
5426 * Unset all positional parameters: set --
5427 * Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
5428 * Set the positional parameters to the expansion of x, even if x expands
5429 * with a leading '-' or '+': set -- $x
5431 * So far, we only support "set -- [argument...]" and some of the short names.
5433 static int builtin_set(char **argv)
5436 char **pp, **g_argv;
5437 char *arg = *++argv;
5441 for (e = G.top_var; e; e = e->next)
5443 return EXIT_SUCCESS;
5447 if (!strcmp(arg, "--")) {
5452 if (arg[0] == '+' || arg[0] == '-') {
5453 for (n = 1; arg[n]; ++n)
5454 if (set_mode(arg[0], arg[n]))
5460 } while ((arg = *++argv) != NULL);
5461 /* Now argv[0] is 1st argument */
5463 /* Only reset global_argv if we didn't process anything */
5465 return EXIT_SUCCESS;
5468 /* NB: G.global_argv[0] ($0) is never freed/changed */
5469 g_argv = G.global_argv;
5470 if (G.global_args_malloced) {
5476 G.global_args_malloced = 1;
5477 pp = xzalloc(sizeof(pp[0]) * 2);
5478 pp[0] = g_argv[0]; /* retain $0 */
5481 /* This realloc's G.global_argv */
5482 G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
5489 return EXIT_SUCCESS;
5491 /* Nothing known, so abort */
5493 bb_error_msg("set: %s: invalid option", arg);
5494 return EXIT_FAILURE;
5497 static int builtin_shift(char **argv)
5503 if (n >= 0 && n < G.global_argc) {
5504 if (G.global_args_malloced) {
5507 free(G.global_argv[m++]);
5510 memmove(&G.global_argv[1], &G.global_argv[n+1],
5511 G.global_argc * sizeof(G.global_argv[0]));
5512 return EXIT_SUCCESS;
5514 return EXIT_FAILURE;
5517 static int builtin_source(char **argv)
5521 if (argv[1] == NULL)
5522 return EXIT_FAILURE;
5524 /* XXX search through $PATH is missing */
5525 input = fopen_for_read(argv[1]);
5527 bb_error_msg("can't open '%s'", argv[1]);
5528 return EXIT_FAILURE;
5530 close_on_exec_on(fileno(input));
5532 /* Now run the file */
5533 /* XXX argv and argc are broken; need to save old G.global_argv
5534 * (pointer only is OK!) on this stack frame,
5535 * set G.global_argv=argv+1, recurse, and restore. */
5536 parse_and_run_file(input);
5538 return G.last_return_code;
5541 static int builtin_umask(char **argv)
5544 const char *arg = argv[1];
5546 new_umask = bb_strtou(arg, NULL, 8);
5548 return EXIT_FAILURE;
5550 new_umask = umask(0);
5551 printf("%.3o\n", (unsigned) new_umask);
5554 return EXIT_SUCCESS;
5557 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
5558 static int builtin_unset(char **argv)
5565 return EXIT_SUCCESS;
5568 if (argv[1][0] == '-') {
5569 switch (argv[1][1]) {
5571 case 'f': if (ENABLE_HUSH_FUNCTIONS) { var = false; break; }
5573 bb_error_msg("unset: %s: invalid option", argv[1]);
5574 return EXIT_FAILURE;
5582 if (unset_local_var(argv[i]))
5585 #if ENABLE_HUSH_FUNCTIONS
5587 unset_local_func(argv[i]);
5593 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
5594 static int builtin_wait(char **argv)
5596 int ret = EXIT_SUCCESS;
5599 if (*++argv == NULL) {
5600 /* Don't care about wait results */
5601 /* Note 1: must wait until there are no more children */
5602 /* Note 2: must be interruptible */
5604 * $ sleep 3 & sleep 6 & wait
5609 * $ sleep 3 & sleep 6 & wait
5613 * ^C <-- after ~4 sec from keyboard
5616 sigaddset(&G.blocked_set, SIGCHLD);
5617 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5620 if (errno == ECHILD)
5622 /* Wait for SIGCHLD or any other signal of interest */
5623 /* sigtimedwait with infinite timeout: */
5624 sig = sigwaitinfo(&G.blocked_set, NULL);
5626 sig = check_and_run_traps(sig);
5627 if (sig && sig != SIGCHLD) { /* see note 2 */
5633 sigdelset(&G.blocked_set, SIGCHLD);
5634 sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
5638 /* This is probably buggy wrt interruptible-ness */
5640 pid_t pid = bb_strtou(*argv, NULL, 10);
5642 /* mimic bash message */
5643 bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
5644 return EXIT_FAILURE;
5646 if (waitpid(pid, &status, 0) == pid) {
5647 if (WIFSIGNALED(status))
5648 ret = 128 + WTERMSIG(status);
5649 else if (WIFEXITED(status))
5650 ret = WEXITSTATUS(status);
5654 bb_perror_msg("wait %s", *argv);
5663 #if ENABLE_HUSH_LOOPS
5664 static int builtin_break(char **argv)
5666 if (G.depth_of_loop == 0) {
5667 bb_error_msg("%s: only meaningful in a loop", argv[0]);
5668 return EXIT_SUCCESS; /* bash compat */
5670 G.flag_break_continue++; /* BC_BREAK = 1 */
5671 G.depth_break_continue = 1;
5673 G.depth_break_continue = bb_strtou(argv[1], NULL, 10);
5674 if (errno || !G.depth_break_continue || argv[2]) {
5675 bb_error_msg("%s: bad arguments", argv[0]);
5676 G.flag_break_continue = BC_BREAK;
5677 G.depth_break_continue = UINT_MAX;
5680 if (G.depth_of_loop < G.depth_break_continue)
5681 G.depth_break_continue = G.depth_of_loop;
5682 return EXIT_SUCCESS;
5685 static int builtin_continue(char **argv)
5687 G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
5688 return builtin_break(argv);