1 /* vi: set sw=4 ts=4: */
3 * sh.c -- 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 * b_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 * Bash grammar not implemented: (how many of these were in original sh?)
40 * $@ (those sure look like weird quoting rules)
42 * ! negation operator for pipes
43 * &> and >& redirection of stdout+stderr
46 * fancy forms of Parameter Expansion
48 * Arithmetic Expansion
49 * <(list) and >(list) Process Substitution
50 * reserved words: case, esac, select, function
51 * Here Documents ( << word )
54 * job handling woefully incomplete and buggy (improved --vda)
55 * reserved word execution woefully incomplete and buggy
57 * port selected bugfixes from post-0.49 busybox lash - done?
58 * finish implementing reserved words: for, while, until, do, done
59 * change { and } from special chars to reserved words
60 * builtins: break, continue, eval, return, set, trap, ulimit
62 * handle children going into background
63 * clean up recognition of null pipes
64 * check setting of global_argc and global_argv
65 * control-C handling, probably with longjmp
66 * follow IFS rules more precisely, including update semantics
67 * figure out what to do with backslash-newline
68 * explain why we use signal instead of sigaction
69 * propagate syntax errors, die on resource errors?
70 * continuation lines, both explicit and implicit - done?
71 * memory leak finding and plugging - done?
72 * more testing, especially quoting rules and redirection
73 * document how quoting rules not precisely followed for variable assignments
74 * maybe change map[] to use 2-bit entries
75 * (eventually) remove all the printf's
77 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
81 #include <glob.h> /* glob, of course */
82 #include <getopt.h> /* should be pretty obvious */
83 /* #include <dmalloc.h> */
86 /* If you comment out one of these below, it will be #defined later
87 * to perform debug printfs to stderr: */
88 #define debug_printf(...) do {} while (0)
89 /* Finer-grained debug switch */
90 #define debug_printf_jobs(...) do {} while (0)
91 #define debug_printf_exec(...) do {} while (0)
95 #define debug_printf(...) fprintf(stderr, __VA_ARGS__)
96 /* broken, of course, but OK for testing */
97 static const char *indenter(int i)
99 static const char blanks[] = " ";
100 return &blanks[sizeof(blanks) - i - 1];
103 #define final_printf debug_printf
105 #ifndef debug_printf_jobs
106 #define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__)
107 #define DEBUG_SHELL_JOBS 1
110 #ifndef debug_printf_exec
111 #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__)
115 #if !ENABLE_HUSH_INTERACTIVE
116 #undef ENABLE_FEATURE_EDITING
117 #define ENABLE_FEATURE_EDITING 0
118 #undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
119 #define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
122 #define SPECIAL_VAR_SYMBOL 03
123 #define FLAG_EXIT_FROM_LOOP 1
124 #define FLAG_PARSE_SEMICOLON (1 << 1) /* symbol ';' is special for parser */
125 #define FLAG_REPARSING (1 << 2) /* >=2nd pass */
129 REDIRECT_OVERWRITE = 2,
135 /* The descrip member of this structure is only used to make debugging
137 static const struct {
139 signed char default_fd;
143 { O_RDONLY, 0, "<" },
144 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
145 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
146 { O_RDONLY, -1, "<<" },
157 /* might eventually control execution */
175 FLAG_END = (1 << RES_NONE ),
176 FLAG_IF = (1 << RES_IF ),
177 FLAG_THEN = (1 << RES_THEN ),
178 FLAG_ELIF = (1 << RES_ELIF ),
179 FLAG_ELSE = (1 << RES_ELSE ),
180 FLAG_FI = (1 << RES_FI ),
181 FLAG_FOR = (1 << RES_FOR ),
182 FLAG_WHILE = (1 << RES_WHILE),
183 FLAG_UNTIL = (1 << RES_UNTIL),
184 FLAG_DO = (1 << RES_DO ),
185 FLAG_DONE = (1 << RES_DONE ),
186 FLAG_IN = (1 << RES_IN ),
187 FLAG_START = (1 << RES_XXXX ),
190 /* This holds pointers to the various results of parsing */
192 struct child_prog *child;
193 struct pipe *list_head;
195 struct redir_struct *pending_redirect;
197 int old_flag; /* for figuring out valid reserved words */
198 struct p_context *stack;
199 int type; /* define type of parser : ";$" common or special symbol */
200 /* How about quoting status? */
203 struct redir_struct {
204 struct redir_struct *next; /* pointer to the next redirect in the list */
205 redir_type type; /* type of redirection */
206 int fd; /* file descriptor being redirected */
207 int dup; /* -1, or file descriptor being duplicated */
208 glob_t word; /* *word.gl_pathv is the filename */
212 pid_t pid; /* 0 if exited */
213 char **argv; /* program name and arguments */
214 struct pipe *group; /* if non-NULL, first in group or subshell */
215 int subshell; /* flag, non-zero if group must be forked */
216 struct redir_struct *redirects; /* I/O redirections */
217 glob_t glob_result; /* result of parameter globbing */
218 int is_stopped; /* is the program currently running? */
219 struct pipe *family; /* pointer back to the child's parent pipe */
220 int sp; /* number of SPECIAL_VAR_SYMBOL */
226 int num_progs; /* total number of programs in job */
227 int running_progs; /* number of programs running (not exited) */
228 char *cmdbuf; /* buffer various argv's point into */
230 int jobid; /* job number */
231 char *cmdtext; /* name of job */
232 pid_t pgrp; /* process group ID for the job */
234 struct child_prog *progs; /* array of commands in pipe */
235 int stopped_progs; /* number of programs alive, but stopped */
236 int job_context; /* bitmask defining current context */
237 pipe_style followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
238 reserved_style r_mode; /* supports if, for, while, until */
242 struct close_me *next;
247 struct variables *next;
254 /* globals, connect us to the outside world
255 * the first three support $?, $#, and $1 */
256 static char **global_argv;
257 static int global_argc;
258 static int last_return_code;
259 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
261 /* "globals" within this file */
262 static const char *ifs;
263 static unsigned char map[256];
264 static int fake_mode;
265 static struct close_me *close_me_head;
266 static const char *cwd;
267 static unsigned last_bg_pid;
268 #if !ENABLE_HUSH_INTERACTIVE
269 enum { interactive_fd = 0 };
271 /* 'interactive_fd' is a fd# open to ctty, if we have one
272 * _AND_ if we decided to mess with job control */
273 static int interactive_fd;
275 static pid_t saved_task_pgrp;
276 static pid_t saved_tty_pgrp;
277 static int last_jobid;
278 static struct pipe *job_list;
280 static const char *PS1;
281 static const char *PS2;
284 #define HUSH_VER_STR "0.02"
285 static struct variables shell_ver = { NULL, "HUSH_VERSION", HUSH_VER_STR, 1, 1 };
286 static struct variables *top_vars = &shell_ver;
298 #define NULL_O_STRING {NULL,0,0,0,0}
299 /* used for initialization:
300 o_string foo = NULL_O_STRING; */
302 /* I can almost use ordinary FILE *. Is open_memstream() universally
303 * available? Where is it documented? */
307 #if ENABLE_HUSH_INTERACTIVE
312 int (*get) (struct in_str *);
313 int (*peek) (struct in_str *);
315 #define b_getch(input) ((input)->get(input))
316 #define b_peek(input) ((input)->peek(input))
318 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
320 struct built_in_command {
321 const char *cmd; /* name */
322 const char *descr; /* description */
323 int (*function) (char **argv); /* function ptr */
326 static void __syntax(int line)
328 bb_error_msg("syntax error hush.c:%d", line);
330 #define syntax() __syntax(__LINE__)
332 /* Index of subroutines: */
333 /* function prototypes for builtins */
334 static int builtin_cd(char **argv);
335 static int builtin_eval(char **argv);
336 static int builtin_exec(char **argv);
337 static int builtin_exit(char **argv);
338 static int builtin_export(char **argv);
340 static int builtin_fg_bg(char **argv);
341 static int builtin_jobs(char **argv);
343 static int builtin_help(char **argv);
344 static int builtin_pwd(char **argv);
345 static int builtin_read(char **argv);
346 static int builtin_set(char **argv);
347 static int builtin_shift(char **argv);
348 static int builtin_source(char **argv);
349 static int builtin_umask(char **argv);
350 static int builtin_unset(char **argv);
351 static int builtin_not_written(char **argv);
352 /* o_string manipulation: */
353 static int b_check_space(o_string *o, int len);
354 static int b_addchr(o_string *o, int ch);
355 static void b_reset(o_string *o);
356 static int b_addqchr(o_string *o, int ch, int quote);
357 static int b_adduint(o_string *o, unsigned i);
358 /* in_str manipulations: */
359 static int static_get(struct in_str *i);
360 static int static_peek(struct in_str *i);
361 static int file_get(struct in_str *i);
362 static int file_peek(struct in_str *i);
363 static void setup_file_in_str(struct in_str *i, FILE *f);
364 static void setup_string_in_str(struct in_str *i, const char *s);
365 /* close_me manipulations: */
366 static void mark_open(int fd);
367 static void mark_closed(int fd);
368 static void close_all(void);
369 /* "run" the final data structures: */
370 static int free_pipe_list(struct pipe *head, int indent);
371 static int free_pipe(struct pipe *pi, int indent);
372 /* really run the final data structures: */
373 static int setup_redirects(struct child_prog *prog, int squirrel[]);
374 static int run_list_real(struct pipe *pi);
375 static void pseudo_exec_argv(char **argv) ATTRIBUTE_NORETURN;
376 static void pseudo_exec(struct child_prog *child) ATTRIBUTE_NORETURN;
377 static int run_pipe_real(struct pipe *pi);
378 /* extended glob support: */
379 static int globhack(const char *src, int flags, glob_t *pglob);
380 static int glob_needed(const char *s);
381 static int xglob(o_string *dest, int flags, glob_t *pglob);
382 /* variable assignment: */
383 static int is_assignment(const char *s);
384 /* data structure manipulation: */
385 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
386 static void initialize_context(struct p_context *ctx);
387 static int done_word(o_string *dest, struct p_context *ctx);
388 static int done_command(struct p_context *ctx);
389 static int done_pipe(struct p_context *ctx, pipe_style type);
390 /* primary string parsing: */
391 static int redirect_dup_num(struct in_str *input);
392 static int redirect_opt_num(o_string *o);
393 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
394 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
395 static const char *lookup_param(const char *src);
396 static char *make_string(char **inp);
397 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
398 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
399 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
401 static int parse_stream_outer(struct in_str *inp, int flag);
402 static int parse_string_outer(const char *s, int flag);
403 static int parse_file_outer(FILE *f);
404 /* job management: */
405 static int checkjobs(struct pipe* fg_pipe);
407 static int checkjobs_and_fg_shell(struct pipe* fg_pipe);
408 static void insert_bg_job(struct pipe *pi);
409 static void remove_bg_job(struct pipe *pi);
410 static void delete_finished_bg_job(struct pipe *pi);
412 int checkjobs_and_fg_shell(struct pipe* fg_pipe); /* never called */
414 /* local variable support */
415 static char **make_list_in(char **inp, char *name);
416 static char *insert_var_value(char *inp);
417 static const char *get_local_var(const char *var);
418 static int set_local_var(const char *s, int flg_export);
419 static void unset_local_var(const char *name);
421 /* Table of built-in functions. They can be forked or not, depending on
422 * context: within pipes, they fork. As simple commands, they do not.
423 * When used in non-forking context, they can change global variables
424 * in the parent shell process. If forked, of course they cannot.
425 * For example, 'unset foo | whatever' will parse and run, but foo will
426 * still be set at the end. */
427 static const struct built_in_command bltins[] = {
429 { "bg", "Resume a job in the background", builtin_fg_bg },
431 { "break", "Exit for, while or until loop", builtin_not_written },
432 { "cd", "Change working directory", builtin_cd },
433 { "continue", "Continue for, while or until loop", builtin_not_written },
434 { "eval", "Construct and run shell command", builtin_eval },
435 { "exec", "Exec command, replacing this shell with the exec'd process",
437 { "exit", "Exit from shell()", builtin_exit },
438 { "export", "Set environment variable", builtin_export },
440 { "fg", "Bring job into the foreground", builtin_fg_bg },
441 { "jobs", "Lists the active jobs", builtin_jobs },
443 { "pwd", "Print current directory", builtin_pwd },
444 { "read", "Input environment variable", builtin_read },
445 { "return", "Return from a function", builtin_not_written },
446 { "set", "Set/unset shell local variables", builtin_set },
447 { "shift", "Shift positional parameters", builtin_shift },
448 { "trap", "Trap signals", builtin_not_written },
449 { "ulimit","Controls resource limits", builtin_not_written },
450 { "umask","Sets file creation mask", builtin_umask },
451 { "unset", "Unset environment variable", builtin_unset },
452 { ".", "Source-in and run commands in a file", builtin_source },
453 { "help", "List shell built-in commands", builtin_help },
459 #if ENABLE_FEATURE_SH_STANDALONE
461 static void signal_SA_RESTART(int sig, void (*handler)(int))
464 sa.sa_handler = handler;
465 sa.sa_flags = SA_RESTART;
466 sigemptyset(&sa.sa_mask);
467 sigaction(sig, &sa, NULL);
471 /* Signals are grouped, we handle them in batches */
472 static void set_fatal_sighandler(void (*handler)(int))
474 signal(SIGILL , handler);
475 signal(SIGTRAP, handler);
476 signal(SIGABRT, handler);
477 signal(SIGFPE , handler);
478 signal(SIGBUS , handler);
479 signal(SIGSEGV, handler);
480 /* bash 3.2 seems to handle these just like 'fatal' ones */
481 signal(SIGHUP , handler);
482 signal(SIGPIPE, handler);
483 signal(SIGALRM, handler);
485 static void set_jobctrl_sighandler(void (*handler)(int))
487 signal(SIGTSTP, handler);
488 signal(SIGTTIN, handler);
489 signal(SIGTTOU, handler);
491 static void set_misc_sighandler(void (*handler)(int))
493 signal(SIGINT , handler);
494 signal(SIGQUIT, handler);
495 signal(SIGTERM, handler);
497 /* SIGCHLD is special and handled separately */
499 #if ENABLE_FEATURE_SH_STANDALONE
500 static void set_every_sighandler(void (*handler)(int))
502 set_fatal_sighandler(handler);
503 set_jobctrl_sighandler(handler);
504 set_misc_sighandler(handler);
505 signal(SIGCHLD, handler);
508 static struct pipe *nofork_pipe;
509 struct nofork_save_area nofork_save;
510 static sigjmp_buf nofork_jb;
512 static void handler_ctrl_c(int sig)
514 debug_printf_jobs("got sig %d\n", sig);
515 // as usual we can have all kinds of nasty problems with leaked malloc data here
516 siglongjmp(nofork_jb, 1);
519 static void handler_ctrl_z(int sig)
523 debug_printf_jobs("got tty sig %d\n", sig);
525 if (pid < 0) /* can't fork. Pretend there were no Ctrl-Z */
527 debug_printf_jobs("bg'ing nofork\n");
528 nofork_save.saved = 0; /* flag the fact that Ctrl-Z was handled */
529 nofork_pipe->running_progs = 1;
530 nofork_pipe->stopped_progs = 0;
531 if (!pid) { /* child */
532 debug_printf_jobs("setting pgrp for child\n");
534 set_every_sighandler(SIG_DFL);
535 raise(SIGTSTP); /* resend TSTP so that child will be stopped */
536 debug_printf_jobs("returning to child\n");
537 /* return to nofork, it will eventually exit now,
538 * not return back to shell */
542 /* finish filling up pipe info */
543 nofork_pipe->pgrp = pid; /* child is in its own pgrp */
544 nofork_pipe->progs[0].pid = pid;
545 nofork_pipe->running_progs = 1;
546 nofork_pipe->stopped_progs = 0;
547 /* parent needs to longjmp out of running nofork.
548 * we will "return" exitcode 0, with child put in background */
549 // as usual we can have all kinds of nasty problems with leaked malloc data here
550 siglongjmp(nofork_jb, 1);
555 /* Restores tty foreground process group, and exits.
556 * May be called as signal handler for fatal signal
557 * (will faithfully resend signal to itself, producing correct exit state)
558 * or called directly with -EXITCODE.
559 * We also call it if xfunc is exiting. */
560 static void sigexit(int sig) ATTRIBUTE_NORETURN;
561 static void sigexit(int sig)
565 /* Disable all signals: job control, SIGPIPE, etc. */
566 sigfillset(&block_all);
567 sigprocmask(SIG_SETMASK, &block_all, NULL);
570 tcsetpgrp(interactive_fd, saved_tty_pgrp);
572 /* Not a signal, just exit */
576 /* Enable only this sig and kill ourself with it */
577 signal(sig, SIG_DFL);
578 sigdelset(&block_all, sig);
579 sigprocmask(SIG_SETMASK, &block_all, NULL);
581 _exit(1); /* Should not reach it */
584 /* Restores tty foreground process group, and exits. */
585 static void hush_exit(int exitcode) ATTRIBUTE_NORETURN;
586 static void hush_exit(int exitcode)
588 fflush(NULL); /* flush all streams */
589 sigexit(- (exitcode & 0xff));
594 #define set_fatal_sighandler(handler) ((void)0)
595 #define set_jobctrl_sighandler(handler) ((void)0)
596 #define set_misc_sighandler(handler) ((void)0)
597 #define hush_exit(e) exit(e)
602 static const char *set_cwd(void)
604 if (cwd == bb_msg_unknown)
605 cwd = NULL; /* xrealloc_getcwd_or_warn(arg) calls free(arg)! */
606 cwd = xrealloc_getcwd_or_warn((char *)cwd);
608 cwd = bb_msg_unknown;
612 /* built-in 'eval' handler */
613 static int builtin_eval(char **argv)
616 int rcode = EXIT_SUCCESS;
619 str = make_string(argv + 1);
620 parse_string_outer(str, FLAG_EXIT_FROM_LOOP |
621 FLAG_PARSE_SEMICOLON);
623 rcode = last_return_code;
628 /* built-in 'cd <path>' handler */
629 static int builtin_cd(char **argv)
633 newdir = getenv("HOME");
637 printf("cd: %s: %s\n", newdir, strerror(errno));
644 /* built-in 'exec' handler */
645 static int builtin_exec(char **argv)
648 return EXIT_SUCCESS; /* Really? */
649 pseudo_exec_argv(argv + 1);
653 /* built-in 'exit' handler */
654 static int builtin_exit(char **argv)
656 // TODO: bash does it ONLY on top-level sh exit (+interacive only?)
657 //puts("exit"); /* bash does it */
658 // TODO: warn if we have background jobs: "There are stopped jobs"
659 // On second consecutive 'exit', exit anyway.
662 hush_exit(last_return_code);
663 /* mimic bash: exit 123abc == exit 255 + error msg */
664 xfunc_error_retval = 255;
665 /* bash: exit -2 == exit 254, no error msg */
666 hush_exit(xatoi(argv[1]) & 0xff);
669 /* built-in 'export VAR=value' handler */
670 static int builtin_export(char **argv)
673 char *name = argv[1];
677 // ash emits: export VAR='VAL'
678 // bash: declare -x VAR="VAL"
679 // (both also escape as needed (quotes, $, etc))
690 const char *value = strchr(name, '=');
694 /* They are exporting something without an =VALUE */
696 value = get_local_var(name);
698 size_t ln = strlen(name);
700 tmp = realloc(name, ln+strlen(value)+2);
704 sprintf(tmp+ln, "=%s", value);
708 /* bash does not return an error when trying to export
709 * an undefined variable. Do likewise. */
715 bb_perror_msg("export");
717 res = set_local_var(name, 1);
725 /* built-in 'fg' and 'bg' handler */
726 static int builtin_fg_bg(char **argv)
733 /* If they gave us no args, assume they want the last backgrounded task */
735 for (pi = job_list; pi; pi = pi->next) {
736 if (pi->jobid == last_jobid) {
740 bb_error_msg("%s: no current job", argv[0]);
743 if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
744 bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
747 for (pi = job_list; pi; pi = pi->next) {
748 if (pi->jobid == jobnum) {
752 bb_error_msg("%s: %d: no such job", argv[0], jobnum);
755 // TODO: bash prints a string representation
756 // of job being foregrounded (like "sleep 1 | cat")
757 if (*argv[0] == 'f') {
758 /* Put the job into the foreground. */
759 tcsetpgrp(interactive_fd, pi->pgrp);
762 /* Restart the processes in the job */
763 debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_progs, pi->pgrp);
764 for (i = 0; i < pi->num_progs; i++) {
765 debug_printf_jobs("reviving pid %d\n", pi->progs[i].pid);
766 pi->progs[i].is_stopped = 0;
768 pi->stopped_progs = 0;
770 i = kill(- pi->pgrp, SIGCONT);
772 if (errno == ESRCH) {
773 delete_finished_bg_job(pi);
776 bb_perror_msg("kill (SIGCONT)");
780 if (*argv[0] == 'f') {
782 return checkjobs_and_fg_shell(pi);
788 /* built-in 'help' handler */
789 static int builtin_help(char **argv ATTRIBUTE_UNUSED)
791 const struct built_in_command *x;
793 printf("\nBuilt-in commands:\n");
794 printf("-------------------\n");
795 for (x = bltins; x->cmd; x++) {
796 if (x->descr == NULL)
798 printf("%s\t%s\n", x->cmd, x->descr);
805 /* built-in 'jobs' handler */
806 static int builtin_jobs(char **argv ATTRIBUTE_UNUSED)
809 const char *status_string;
811 for (job = job_list; job; job = job->next) {
812 if (job->running_progs == job->stopped_progs)
813 status_string = "Stopped";
815 status_string = "Running";
817 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
823 /* built-in 'pwd' handler */
824 static int builtin_pwd(char **argv ATTRIBUTE_UNUSED)
830 /* built-in 'read VAR' handler */
831 static int builtin_read(char **argv)
839 string[0] = '\0'; /* In case stdin has only EOF */
841 fgets(string, sizeof(string), stdin);
843 var = malloc(strlen(argv[1]) + strlen(string) + 2);
845 sprintf(var, "%s=%s", argv[1], string);
846 res = set_local_var(var, 0);
850 bb_perror_msg("read");
851 free(var); /* So not move up to avoid breaking errno */
854 do res = getchar(); while (res != '\n' && res != EOF);
858 /* built-in 'set VAR=value' handler */
859 static int builtin_set(char **argv)
861 char *temp = argv[1];
865 for (e = top_vars; e; e = e->next)
866 printf("%s=%s\n", e->name, e->value);
868 set_local_var(temp, 0);
874 /* Built-in 'shift' handler */
875 static int builtin_shift(char **argv)
881 if (n >= 0 && n < global_argc) {
882 /* XXX This probably breaks $0 */
890 /* Built-in '.' handler (read-in and execute commands from file) */
891 static int builtin_source(char **argv)
899 /* XXX search through $PATH is missing */
900 input = fopen(argv[1], "r");
902 bb_error_msg("cannot open '%s'", argv[1]);
906 /* Now run the file */
907 /* XXX argv and argc are broken; need to save old global_argv
908 * (pointer only is OK!) on this stack frame,
909 * set global_argv=argv+1, recurse, and restore. */
910 mark_open(fileno(input));
911 status = parse_file_outer(input);
912 mark_closed(fileno(input));
917 static int builtin_umask(char **argv)
920 const char *arg = argv[1];
923 new_umask = strtoul(arg, &end, 8);
924 if (*end != '\0' || end == arg) {
928 new_umask = umask(0);
929 printf("%.3o\n", (unsigned) new_umask);
935 /* built-in 'unset VAR' handler */
936 static int builtin_unset(char **argv)
938 /* bash returned already true */
939 unset_local_var(argv[1]);
943 static int builtin_not_written(char **argv)
945 printf("builtin_%s not written\n", argv[0]);
949 static int b_check_space(o_string *o, int len)
951 /* It would be easy to drop a more restrictive policy
952 * in here, such as setting a maximum string length */
953 if (o->length + len > o->maxlen) {
954 char *old_data = o->data;
955 /* assert(data == NULL || o->maxlen != 0); */
956 o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
957 o->data = realloc(o->data, 1 + o->maxlen);
958 if (o->data == NULL) {
962 return o->data == NULL;
965 static int b_addchr(o_string *o, int ch)
967 debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
968 if (b_check_space(o, 1))
970 o->data[o->length] = ch;
972 o->data[o->length] = '\0';
976 static void b_reset(o_string *o)
984 static void b_free(o_string *o)
992 /* My analysis of quoting semantics tells me that state information
993 * is associated with a destination, not a source.
995 static int b_addqchr(o_string *o, int ch, int quote)
997 if (quote && strchr("*?[\\", ch)) {
999 rc = b_addchr(o, '\\');
1003 return b_addchr(o, ch);
1006 static int b_adduint(o_string *o, unsigned i)
1009 char buf[sizeof(unsigned)*3 + 1];
1011 *(utoa_to_buf(i, buf, sizeof(buf))) = '\0';
1012 /* no escape checking necessary */
1013 do r = b_addchr(o, *p++); while (r == 0 && *p);
1017 static int static_get(struct in_str *i)
1020 if (ch == '\0') return EOF;
1024 static int static_peek(struct in_str *i)
1029 #if ENABLE_HUSH_INTERACTIVE
1030 static void cmdedit_set_initial_prompt(void)
1032 #if !ENABLE_FEATURE_EDITING_FANCY_PROMPT
1035 PS1 = getenv("PS1");
1041 static const char* setup_prompt_string(int promptmode)
1043 const char *prompt_str;
1044 debug_printf("setup_prompt_string %d ", promptmode);
1045 #if !ENABLE_FEATURE_EDITING_FANCY_PROMPT
1046 /* Set up the prompt */
1047 if (promptmode == 1) {
1050 ns = xmalloc(strlen(cwd)+4);
1051 sprintf(ns, "%s %s", cwd, (geteuid() != 0) ? "$ " : "# ");
1058 prompt_str = (promptmode == 1) ? PS1 : PS2;
1060 debug_printf("result %s\n", prompt_str);
1065 #if ENABLE_FEATURE_EDITING
1066 static line_input_t *line_input_state;
1069 #if ENABLE_HUSH_INTERACTIVE
1070 static int get_user_input(struct in_str *i)
1072 static char the_command[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
1075 const char *prompt_str;
1076 prompt_str = setup_prompt_string(i->promptmode);
1077 #if ENABLE_FEATURE_EDITING
1079 ** enable command line editing only while a command line
1080 ** is actually being read; otherwise, we'll end up bequeathing
1081 ** atexit() handlers and other unwanted stuff to our
1082 ** child processes (rob@sysgo.de)
1084 r = read_line_input(prompt_str, the_command, BUFSIZ, line_input_state);
1086 fputs(prompt_str, stdout);
1088 the_command[0] = r = fgetc(i->file);
1089 the_command[1] = '\0';
1093 return r; /* < 0 == EOF. Not meaningful otherwise */
1097 /* This is the magic location that prints prompts
1098 * and gets data back from the user */
1099 static int file_get(struct in_str *i)
1104 /* If there is data waiting, eat it up */
1105 if (i->p && *i->p) {
1108 /* need to double check i->file because we might be doing something
1109 * more complicated by now, like sourcing or substituting. */
1110 #if ENABLE_HUSH_INTERACTIVE
1111 if (interactive_fd && i->__promptme && i->file == stdin) {
1112 while (!i->p || !(interactive_fd && i->p[0])) {
1113 if (get_user_input(i) < 0)
1118 if (i->p && *i->p) {
1124 ch = fgetc(i->file);
1126 debug_printf("b_getch: got a %d\n", ch);
1128 #if ENABLE_HUSH_INTERACTIVE
1135 /* All the callers guarantee this routine will never be
1136 * used right after a newline, so prompting is not needed.
1138 static int file_peek(struct in_str *i)
1140 if (i->p && *i->p) {
1143 i->peek_buf[0] = fgetc(i->file);
1144 i->peek_buf[1] = '\0';
1146 debug_printf("b_peek: got a %d\n", *i->p);
1150 static void setup_file_in_str(struct in_str *i, FILE *f)
1152 i->peek = file_peek;
1154 #if ENABLE_HUSH_INTERACTIVE
1162 static void setup_string_in_str(struct in_str *i, const char *s)
1164 i->peek = static_peek;
1165 i->get = static_get;
1166 #if ENABLE_HUSH_INTERACTIVE
1173 static void mark_open(int fd)
1175 struct close_me *new = xmalloc(sizeof(struct close_me));
1177 new->next = close_me_head;
1178 close_me_head = new;
1181 static void mark_closed(int fd)
1183 struct close_me *tmp;
1184 if (close_me_head == NULL || close_me_head->fd != fd)
1185 bb_error_msg_and_die("corrupt close_me");
1186 tmp = close_me_head;
1187 close_me_head = close_me_head->next;
1191 static void close_all(void)
1194 for (c = close_me_head; c; c = c->next) {
1197 close_me_head = NULL;
1200 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
1201 * and stderr if they are redirected. */
1202 static int setup_redirects(struct child_prog *prog, int squirrel[])
1205 struct redir_struct *redir;
1207 for (redir = prog->redirects; redir; redir = redir->next) {
1208 if (redir->dup == -1 && redir->word.gl_pathv == NULL) {
1209 /* something went wrong in the parse. Pretend it didn't happen */
1212 if (redir->dup == -1) {
1213 mode = redir_table[redir->type].mode;
1214 openfd = open_or_warn(redir->word.gl_pathv[0], mode);
1216 /* this could get lost if stderr has been redirected, but
1217 bash and ash both lose it as well (though zsh doesn't!) */
1221 openfd = redir->dup;
1224 if (openfd != redir->fd) {
1225 if (squirrel && redir->fd < 3) {
1226 squirrel[redir->fd] = dup(redir->fd);
1231 dup2(openfd, redir->fd);
1232 if (redir->dup == -1)
1240 static void restore_redirects(int squirrel[])
1243 for (i = 0; i < 3; i++) {
1246 /* No error checking. I sure wouldn't know what
1247 * to do with an error if I found one! */
1255 /* XXX no exit() here. If you don't exec, use _exit instead.
1256 * The at_exit handlers apparently confuse the calling process,
1257 * in particular stdin handling. Not sure why? -- because of vfork! (vda) */
1258 static void pseudo_exec_argv(char **argv)
1262 const struct built_in_command *x;
1264 for (i = 0; is_assignment(argv[i]); i++) {
1265 debug_printf("pid %d environment modification: %s\n",
1267 // FIXME: vfork case??
1268 p = insert_var_value(argv[i]);
1274 /* If a variable is assigned in a forest, and nobody listens,
1275 * was it ever really set?
1277 if (argv[0] == NULL) {
1278 _exit(EXIT_SUCCESS);
1282 * Check if the command matches any of the builtins.
1283 * Depending on context, this might be redundant. But it's
1284 * easier to waste a few CPU cycles than it is to figure out
1285 * if this is one of those cases.
1287 for (x = bltins; x->cmd; x++) {
1288 if (strcmp(argv[0], x->cmd) == 0) {
1289 debug_printf("builtin exec %s\n", argv[0]);
1290 rcode = x->function(argv);
1296 /* Check if the command matches any busybox internal commands
1298 * FIXME: This feature is not 100% safe, since
1299 * BusyBox is not fully reentrant, so we have no guarantee the things
1300 * from the .bss are still zeroed, or that things from .data are still
1301 * at their defaults. We could exec ourself from /proc/self/exe, but I
1302 * really dislike relying on /proc for things. We could exec ourself
1303 * from global_argv[0], but if we are in a chroot, we may not be able
1304 * to find ourself... */
1305 #if ENABLE_FEATURE_SH_STANDALONE
1306 debug_printf("running applet %s\n", argv[0]);
1307 run_applet_and_exit(argv[0], argv);
1308 // is it ok that run_applet_and_exit() does exit(), not _exit()?
1309 // NB: IIRC on NOMMU we are after _vfork_, not fork!
1311 debug_printf("exec of %s\n", argv[0]);
1312 execvp(argv[0], argv);
1313 bb_perror_msg("cannot exec '%s'", argv[0]);
1317 static void pseudo_exec(struct child_prog *child)
1319 // FIXME: buggy wrt NOMMU! Must not modify any global data
1320 // until it does exec/_exit, but currently it does.
1324 pseudo_exec_argv(child->argv);
1328 // FIXME: do not modify globals! Think vfork!
1329 #if ENABLE_HUSH_INTERACTIVE
1330 interactive_fd = 0; /* crucial!!!! */
1332 debug_printf_exec("pseudo_exec: run_list_real\n");
1333 rcode = run_list_real(child->group);
1334 /* OK to leak memory by not calling free_pipe_list,
1335 * since this process is about to exit */
1339 /* Can happen. See what bash does with ">foo" by itself. */
1340 debug_printf("trying to pseudo_exec null command\n");
1341 _exit(EXIT_SUCCESS);
1345 static const char *get_cmdtext(struct pipe *pi)
1351 /* This is subtle. ->cmdtext is created only on first backgrounding.
1352 * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
1353 * On subsequent bg argv can be trashed, but we won't use it */
1356 argv = pi->progs[0].argv;
1357 if (!argv || !argv[0])
1358 return (pi->cmdtext = xzalloc(1));
1361 do len += strlen(*argv) + 1; while (*++argv);
1362 pi->cmdtext = p = xmalloc(len);
1363 argv = pi->progs[0].argv;
1365 len = strlen(*argv);
1366 memcpy(p, *argv, len);
1376 static void insert_bg_job(struct pipe *pi)
1378 struct pipe *thejob;
1380 /* Linear search for the ID of the job to use */
1382 for (thejob = job_list; thejob; thejob = thejob->next)
1383 if (thejob->jobid >= pi->jobid)
1384 pi->jobid = thejob->jobid + 1;
1386 /* add thejob to the list of running jobs */
1388 thejob = job_list = xmalloc(sizeof(*thejob));
1390 for (thejob = job_list; thejob->next; thejob = thejob->next)
1392 thejob->next = xmalloc(sizeof(*thejob));
1393 thejob = thejob->next;
1396 /* physically copy the struct job */
1397 memcpy(thejob, pi, sizeof(struct pipe));
1398 thejob->progs = xmalloc(sizeof(pi->progs[0]) * pi->num_progs);
1399 memcpy(thejob->progs, pi->progs, sizeof(pi->progs[0]) * pi->num_progs);
1400 thejob->next = NULL;
1401 /*seems to be wrong:*/
1402 /*thejob->running_progs = thejob->num_progs;*/
1403 /*thejob->stopped_progs = 0;*/
1404 thejob->cmdtext = xstrdup(get_cmdtext(pi));
1406 /* we don't wait for background thejobs to return -- append it
1407 to the list of backgrounded thejobs and leave it alone */
1408 printf("[%d] %d %s\n", thejob->jobid, thejob->progs[0].pid, thejob->cmdtext);
1409 last_bg_pid = thejob->progs[0].pid;
1410 last_jobid = thejob->jobid;
1413 static void remove_bg_job(struct pipe *pi)
1415 struct pipe *prev_pipe;
1417 if (pi == job_list) {
1418 job_list = pi->next;
1420 prev_pipe = job_list;
1421 while (prev_pipe->next != pi)
1422 prev_pipe = prev_pipe->next;
1423 prev_pipe->next = pi->next;
1426 last_jobid = job_list->jobid;
1431 /* remove a backgrounded job */
1432 static void delete_finished_bg_job(struct pipe *pi)
1435 pi->stopped_progs = 0;
1441 /* Checks to see if any processes have exited -- if they
1442 have, figure out why and see if a job has completed */
1443 static int checkjobs(struct pipe* fg_pipe)
1454 attributes = WUNTRACED;
1455 if (fg_pipe == NULL) {
1456 attributes |= WNOHANG;
1459 /* Do we do this right?
1460 * bash-3.00# sleep 20 | false
1462 * [3]+ Stopped sleep 20 | false
1463 * bash-3.00# echo $?
1464 * 1 <========== bg pipe is not fully done, but exitcode is already known!
1467 //FIXME: non-interactive bash does not continue even if all processes in fg pipe
1468 //are stopped. Testcase: "cat | cat" in a script (not on command line)
1469 // + killall -STOP cat
1472 while ((childpid = waitpid(-1, &status, attributes)) > 0) {
1473 const int dead = WIFEXITED(status) || WIFSIGNALED(status);
1475 #ifdef DEBUG_SHELL_JOBS
1476 if (WIFSTOPPED(status))
1477 debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
1478 childpid, WSTOPSIG(status), WEXITSTATUS(status));
1479 if (WIFSIGNALED(status))
1480 debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
1481 childpid, WTERMSIG(status), WEXITSTATUS(status));
1482 if (WIFEXITED(status))
1483 debug_printf_jobs("pid %d exited, exitcode %d\n",
1484 childpid, WEXITSTATUS(status));
1486 /* Were we asked to wait for fg pipe? */
1489 for (i = 0; i < fg_pipe->num_progs; i++) {
1490 debug_printf_jobs("check pid %d\n", fg_pipe->progs[i].pid);
1491 if (fg_pipe->progs[i].pid == childpid) {
1492 /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
1494 fg_pipe->progs[i].pid = 0;
1495 fg_pipe->running_progs--;
1496 if (i == fg_pipe->num_progs-1)
1497 /* last process gives overall exitstatus */
1498 rcode = WEXITSTATUS(status);
1500 fg_pipe->progs[i].is_stopped = 1;
1501 fg_pipe->stopped_progs++;
1503 debug_printf_jobs("fg_pipe: running_progs %d stopped_progs %d\n",
1504 fg_pipe->running_progs, fg_pipe->stopped_progs);
1505 if (fg_pipe->running_progs - fg_pipe->stopped_progs <= 0) {
1506 /* All processes in fg pipe have exited/stopped */
1508 if (fg_pipe->running_progs)
1509 insert_bg_job(fg_pipe);
1513 /* There are still running processes in the fg pipe */
1517 /* fall through to searching process in bg pipes */
1521 /* We asked to wait for bg or orphaned children */
1522 /* No need to remember exitcode in this case */
1523 for (pi = job_list; pi; pi = pi->next) {
1525 while (prognum < pi->num_progs) {
1526 if (pi->progs[prognum].pid == childpid)
1527 goto found_pi_and_prognum;
1533 /* Happens when shell is used as init process (init=/bin/sh) */
1534 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
1538 found_pi_and_prognum:
1541 pi->progs[prognum].pid = 0;
1542 pi->running_progs--;
1543 if (!pi->running_progs) {
1544 printf(JOB_STATUS_FORMAT, pi->jobid,
1545 "Done", pi->cmdtext);
1546 delete_finished_bg_job(pi);
1550 pi->stopped_progs++;
1551 pi->progs[prognum].is_stopped = 1;
1556 /* wait found no children or failed */
1558 if (childpid && errno != ECHILD)
1559 bb_perror_msg("waitpid");
1561 /* move the shell to the foreground */
1562 //if (interactive_fd && tcsetpgrp(interactive_fd, getpgid(0)))
1563 // bb_perror_msg("tcsetpgrp-2");
1568 static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
1571 int rcode = checkjobs(fg_pipe);
1572 /* Job finished, move the shell to the foreground */
1574 debug_printf("fg'ing ourself: getpgid(0)=%d\n", (int)p);
1575 if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY)
1576 bb_perror_msg("tcsetpgrp-4a");
1581 #if ENABLE_FEATURE_SH_STANDALONE
1582 /* run_pipe_real's helper */
1583 static int run_single_fg_nofork(struct pipe *pi, const struct bb_applet *a,
1588 /* TSTP handler will store pid etc in pi */
1590 save_nofork_data(&nofork_save);
1591 if (sigsetjmp(nofork_jb, 1) == 0) {
1592 signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
1593 signal(SIGINT, handler_ctrl_c);
1594 rcode = run_nofork_applet_prime(&nofork_save, a, argv);
1595 if (--nofork_save.saved != 0) {
1596 /* Ctrl-Z forked, we are child */
1601 /* Ctrl-Z forked, we are parent; or Ctrl-C.
1602 * Sighandler has longjmped us here */
1603 signal(SIGINT, SIG_IGN);
1604 signal(SIGTSTP, SIG_IGN);
1605 debug_printf_jobs("Exiting nofork early\n");
1606 restore_nofork_data(&nofork_save);
1607 if (nofork_save.saved == 0) /* Ctrl-Z, not Ctrl-C */
1610 putchar('\n'); /* bash does this on Ctrl-C */
1613 return run_nofork_applet(a, argv);
1618 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1619 * to finish. See checkjobs().
1621 * return code is normally -1, when the caller has to wait for children
1622 * to finish to determine the exit status of the pipe. If the pipe
1623 * is a simple builtin command, however, the action is done by the
1624 * time run_pipe_real returns, and the exit code is provided as the
1627 * The input of the pipe is always stdin, the output is always
1628 * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1629 * because it tries to avoid running the command substitution in
1630 * subshell, when that is in fact necessary. The subshell process
1631 * now has its stdout directed to the input of the appropriate pipe,
1632 * so this routine is noticeably simpler.
1634 static int run_pipe_real(struct pipe *pi)
1637 int nextin, nextout;
1638 int pipefds[2]; /* pipefds[0] is for reading */
1639 struct child_prog *child;
1640 const struct built_in_command *x;
1642 /* it is not always needed, but we aim to smaller code */
1643 int squirrel[] = { -1, -1, -1 };
1645 const int single_fg = (pi->num_progs == 1 && pi->followup != PIPE_BG);
1647 debug_printf_exec("run_pipe_real start:\n");
1653 pi->running_progs = 0;
1654 pi->stopped_progs = 0;
1656 /* Check if this is a simple builtin (not part of a pipe).
1657 * Builtins within pipes have to fork anyway, and are handled in
1658 * pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
1660 child = &(pi->progs[0]);
1661 if (single_fg && child->group && child->subshell == 0) {
1662 debug_printf("non-subshell grouping\n");
1663 setup_redirects(child, squirrel);
1664 /* XXX could we merge code with following builtin case,
1665 * by creating a pseudo builtin that calls run_list_real? */
1666 debug_printf_exec(": run_list_real\n");
1667 rcode = run_list_real(child->group);
1668 restore_redirects(squirrel);
1669 debug_printf_exec("run_pipe_real return %d\n", rcode);
1673 if (single_fg && child->argv != NULL) {
1674 char **argv = child->argv;
1676 for (i = 0; is_assignment(argv[i]); i++)
1678 if (i != 0 && argv[i] == NULL) {
1679 /* assignments, but no command: set the local environment */
1680 for (i = 0; argv[i] != NULL; i++) {
1681 /* Ok, this case is tricky. We have to decide if this is a
1682 * local variable, or an already exported variable. If it is
1683 * already exported, we have to export the new value. If it is
1684 * not exported, we need only set this as a local variable.
1685 * This junk is all to decide whether or not to export this
1689 name = xstrdup(argv[i]);
1690 debug_printf("Local environment set: %s\n", name);
1691 value = strchr(name, '=');
1694 if (get_local_var(name)) {
1698 p = insert_var_value(argv[i]);
1699 set_local_var(p, export_me);
1703 return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */
1705 for (i = 0; is_assignment(argv[i]); i++) {
1706 p = insert_var_value(argv[i]);
1716 str = make_string(argv + i);
1717 debug_printf_exec(": parse_string_outer '%s'\n", str);
1718 parse_string_outer(str, FLAG_EXIT_FROM_LOOP | FLAG_REPARSING);
1720 debug_printf_exec("run_pipe_real return %d\n", last_return_code);
1721 return last_return_code;
1723 for (x = bltins; x->cmd; x++) {
1724 if (strcmp(argv[i], x->cmd) == 0) {
1725 if (x->function == builtin_exec && argv[i+1] == NULL) {
1726 debug_printf("magic exec\n");
1727 setup_redirects(child, NULL);
1728 return EXIT_SUCCESS;
1730 debug_printf("builtin inline %s\n", argv[0]);
1731 /* XXX setup_redirects acts on file descriptors, not FILEs.
1732 * This is perfect for work that comes after exec().
1733 * Is it really safe for inline use? Experimentally,
1734 * things seem to work with glibc. */
1735 // TODO: fflush(NULL)?
1736 setup_redirects(child, squirrel);
1737 debug_printf_exec(": builtin '%s' '%s'...\n", x->cmd, argv[i+1]);
1738 rcode = x->function(argv + i);
1739 restore_redirects(squirrel);
1740 debug_printf_exec("run_pipe_real return %d\n", rcode);
1744 #if ENABLE_FEATURE_SH_STANDALONE
1746 const struct bb_applet *a = find_applet_by_name(argv[i]);
1747 if (a && a->nofork) {
1748 setup_redirects(child, squirrel);
1749 debug_printf_exec(": run_single_fg_nofork '%s' '%s'...\n", argv[i], argv[i+1]);
1750 rcode = run_single_fg_nofork(pi, a, argv + i);
1751 restore_redirects(squirrel);
1752 debug_printf_exec("run_pipe_real return %d\n", rcode);
1759 /* Going to fork a child per each pipe member */
1761 /* Disable job control signals for shell (parent) and
1762 * for initial child code after fork */
1763 set_jobctrl_sighandler(SIG_IGN);
1765 for (i = 0; i < pi->num_progs; i++) {
1766 child = &(pi->progs[i]);
1767 debug_printf_exec(": pipe member '%s' '%s'...\n", child->argv[0], child->argv[1]);
1769 /* pipes are inserted between pairs of commands */
1770 if ((i + 1) < pi->num_progs) {
1771 if (pipe(pipefds) < 0)
1772 bb_perror_msg_and_die("pipe");
1773 nextout = pipefds[1];
1779 /* XXX test for failed fork()? */
1781 child->pid = fork();
1783 child->pid = vfork();
1785 if (!child->pid) { /* child */
1786 /* Every child adds itself to new process group
1787 * with pgid == pid of first child in pipe */
1789 if (interactive_fd) {
1790 /* Don't do pgrp restore anymore on fatal signals */
1791 set_fatal_sighandler(SIG_DFL);
1792 if (pi->pgrp < 0) /* true for 1st process only */
1793 pi->pgrp = getpid();
1794 if (setpgid(0, pi->pgrp) == 0 && pi->followup != PIPE_BG) {
1795 /* We do it in *every* child, not just first,
1797 tcsetpgrp(interactive_fd, pi->pgrp);
1801 // in non-interactive case fatal sigs are already SIG_DFL
1811 if (pipefds[0] != -1) {
1812 close(pipefds[0]); /* opposite end of our output pipe */
1814 /* Like bash, explicit redirects override pipes,
1815 * and the pipe fd is available for dup'ing. */
1816 setup_redirects(child, NULL);
1818 /* Restore default handlers just prior to exec */
1819 set_jobctrl_sighandler(SIG_DFL);
1820 set_misc_sighandler(SIG_DFL);
1821 signal(SIGCHLD, SIG_DFL);
1825 pi->running_progs++;
1828 /* Second and next children need to know pid of first one */
1830 pi->pgrp = child->pid;
1833 /* Don't check for errors. The child may be dead already,
1834 * in which case setpgid returns error code EACCES. */
1835 //why we do it at all?? child does it itself
1836 //if (interactive_fd)
1837 // setpgid(child->pid, pi->pgrp);
1844 /* If there isn't another process, nextin is garbage
1845 but it doesn't matter */
1846 nextin = pipefds[0];
1848 debug_printf_exec("run_pipe_real return -1\n");
1852 // NB: called by pseudo_exec, and therefore must not modify any
1853 // global data until exec/_exit (we can be a child after vfork!)
1854 static int run_list_real(struct pipe *pi)
1856 char *save_name = NULL;
1858 char **save_list = NULL;
1862 int rcode = 0, flag_skip = 1;
1863 int flag_restore = 0;
1864 int if_code = 0, next_if_code = 0; /* need double-buffer to handle elif */
1865 reserved_style rmode, skip_more_in_this_rmode = RES_XXXX;
1867 debug_printf_exec("run_list_real start:\n");
1869 /* check syntax for "for" */
1870 for (rpipe = pi; rpipe; rpipe = rpipe->next) {
1871 if ((rpipe->r_mode == RES_IN || rpipe->r_mode == RES_FOR)
1872 && (rpipe->next == NULL)
1875 debug_printf_exec("run_list_real return 1\n");
1878 if ((rpipe->r_mode == RES_IN && rpipe->next->r_mode == RES_IN && rpipe->next->progs->argv != NULL)
1879 || (rpipe->r_mode == RES_FOR && rpipe->next->r_mode != RES_IN)
1882 debug_printf_exec("run_list_real return 1\n");
1886 for (; pi; pi = (flag_restore != 0) ? rpipe : pi->next) {
1887 if (pi->r_mode == RES_WHILE || pi->r_mode == RES_UNTIL
1888 || pi->r_mode == RES_FOR
1897 debug_printf("rmode=%d if_code=%d next_if_code=%d skip_more=%d\n",
1898 rmode, if_code, next_if_code, skip_more_in_this_rmode);
1899 if (rmode == skip_more_in_this_rmode && flag_skip) {
1900 if (pi->followup == PIPE_SEQ)
1905 skip_more_in_this_rmode = RES_XXXX;
1906 if (rmode == RES_THEN || rmode == RES_ELSE)
1907 if_code = next_if_code;
1908 if (rmode == RES_THEN && if_code)
1910 if (rmode == RES_ELSE && !if_code)
1912 if (rmode == RES_ELIF && !if_code)
1914 if (rmode == RES_FOR && pi->num_progs) {
1916 /* if no variable values after "in" we skip "for" */
1917 if (!pi->next->progs->argv)
1919 /* create list of variable values */
1920 list = make_list_in(pi->next->progs->argv,
1921 pi->progs->argv[0]);
1923 save_name = pi->progs->argv[0];
1924 pi->progs->argv[0] = NULL;
1928 free(pi->progs->argv[0]);
1932 pi->progs->argv[0] = save_name;
1933 pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0];
1936 /* insert new value from list for variable */
1937 if (pi->progs->argv[0])
1938 free(pi->progs->argv[0]);
1939 pi->progs->argv[0] = *list++;
1940 pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0];
1942 if (rmode == RES_IN)
1944 if (rmode == RES_DO) {
1948 if (rmode == RES_DONE) {
1955 if (pi->num_progs == 0)
1957 save_num_progs = pi->num_progs; /* save number of programs */
1958 debug_printf_exec(": run_pipe_real with %d members\n", pi->num_progs);
1959 rcode = run_pipe_real(pi);
1961 /* We only ran a builtin: rcode was set by the return value
1962 * of run_pipe_real(), and we don't need to wait for anything. */
1963 } else if (pi->followup == PIPE_BG) {
1964 /* XXX check bash's behavior with nontrivial pipes */
1965 /* XXX compute jobid */
1966 /* XXX what does bash do with attempts to background builtins? */
1970 rcode = EXIT_SUCCESS;
1973 if (interactive_fd) {
1974 rcode = checkjobs_and_fg_shell(pi);
1978 rcode = checkjobs(pi);
1980 debug_printf("checkjobs returned %d\n", rcode);
1982 last_return_code = rcode;
1983 pi->num_progs = save_num_progs; /* restore number of programs */
1984 if (rmode == RES_IF || rmode == RES_ELIF)
1985 next_if_code = rcode; /* can be overwritten a number of times */
1986 if (rmode == RES_WHILE)
1987 flag_rep = !last_return_code;
1988 if (rmode == RES_UNTIL)
1989 flag_rep = last_return_code;
1990 if ((rcode == EXIT_SUCCESS && pi->followup == PIPE_OR)
1991 || (rcode != EXIT_SUCCESS && pi->followup == PIPE_AND)
1993 skip_more_in_this_rmode = rmode;
1997 debug_printf_exec("run_list_real return %d\n", rcode);
2001 /* return code is the exit status of the pipe */
2002 static int free_pipe(struct pipe *pi, int indent)
2005 struct child_prog *child;
2006 struct redir_struct *r, *rnext;
2007 int a, i, ret_code = 0;
2009 if (pi->stopped_progs > 0)
2011 final_printf("%s run pipe: (pid %d)\n", indenter(indent), getpid());
2012 for (i = 0; i < pi->num_progs; i++) {
2013 child = &pi->progs[i];
2014 final_printf("%s command %d:\n", indenter(indent), i);
2016 for (a = 0, p = child->argv; *p; a++, p++) {
2017 final_printf("%s argv[%d] = %s\n", indenter(indent), a, *p);
2019 globfree(&child->glob_result);
2021 } else if (child->group) {
2022 final_printf("%s begin group (subshell:%d)\n", indenter(indent), child->subshell);
2023 ret_code = free_pipe_list(child->group, indent+3);
2024 final_printf("%s end group\n", indenter(indent));
2026 final_printf("%s (nil)\n", indenter(indent));
2028 for (r = child->redirects; r; r = rnext) {
2029 final_printf("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->type].descrip);
2031 /* guard against the case >$FOO, where foo is unset or blank */
2032 if (r->word.gl_pathv) {
2033 final_printf(" %s\n", *r->word.gl_pathv);
2037 final_printf("&%d\n", r->dup);
2042 child->redirects = NULL;
2044 free(pi->progs); /* children are an array, they get freed all at once */
2053 static int free_pipe_list(struct pipe *head, int indent)
2055 int rcode = 0; /* if list has no members */
2056 struct pipe *pi, *next;
2057 for (pi = head; pi; pi = next) {
2058 final_printf("%s pipe reserved mode %d\n", indenter(indent), pi->r_mode);
2059 rcode = free_pipe(pi, indent);
2060 final_printf("%s pipe followup code %d\n", indenter(indent), pi->followup);
2062 /*pi->next = NULL;*/
2068 /* Select which version we will use */
2069 static int run_list(struct pipe *pi)
2072 if (fake_mode == 0) {
2073 debug_printf_exec("run_list: run_list_real with %d members\n", pi->num_progs);
2074 rcode = run_list_real(pi);
2076 /* free_pipe_list has the side effect of clearing memory
2077 * In the long run that function can be merged with run_list_real,
2078 * but doing that now would hobble the debugging effort. */
2079 free_pipe_list(pi,0);
2083 /* The API for glob is arguably broken. This routine pushes a non-matching
2084 * string into the output structure, removing non-backslashed backslashes.
2085 * If someone can prove me wrong, by performing this function within the
2086 * original glob(3) api, feel free to rewrite this routine into oblivion.
2087 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
2088 * XXX broken if the last character is '\\', check that before calling.
2090 static int globhack(const char *src, int flags, glob_t *pglob)
2095 for (cnt = 1, s = src; s && *s; s++) {
2096 if (*s == '\\') s++;
2101 return GLOB_NOSPACE;
2102 if (!(flags & GLOB_APPEND)) {
2103 pglob->gl_pathv = NULL;
2104 pglob->gl_pathc = 0;
2108 pathc = ++pglob->gl_pathc;
2109 pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
2110 if (pglob->gl_pathv == NULL)
2111 return GLOB_NOSPACE;
2112 pglob->gl_pathv[pathc-1] = dest;
2113 pglob->gl_pathv[pathc] = NULL;
2114 for (s = src; s && *s; s++, dest++) {
2115 if (*s == '\\') s++;
2122 /* XXX broken if the last character is '\\', check that before calling */
2123 static int glob_needed(const char *s)
2126 if (*s == '\\') s++;
2127 if (strchr("*[?", *s)) return 1;
2132 static int xglob(o_string *dest, int flags, glob_t *pglob)
2136 /* short-circuit for null word */
2137 /* we can code this better when the debug_printf's are gone */
2138 if (dest->length == 0) {
2139 if (dest->nonnull) {
2140 /* bash man page calls this an "explicit" null */
2141 gr = globhack(dest->data, flags, pglob);
2142 debug_printf("globhack returned %d\n", gr);
2146 } else if (glob_needed(dest->data)) {
2147 gr = glob(dest->data, flags, NULL, pglob);
2148 debug_printf("glob returned %d\n", gr);
2149 if (gr == GLOB_NOMATCH) {
2150 /* quote removal, or more accurately, backslash removal */
2151 gr = globhack(dest->data, flags, pglob);
2152 debug_printf("globhack returned %d\n", gr);
2155 gr = globhack(dest->data, flags, pglob);
2156 debug_printf("globhack returned %d\n", gr);
2158 if (gr == GLOB_NOSPACE)
2159 bb_error_msg_and_die("out of memory during glob");
2160 if (gr != 0) { /* GLOB_ABORTED ? */
2161 bb_error_msg("glob(3) error %d", gr);
2163 /* globprint(glob_target); */
2167 static char **make_list_in(char **inp, char *name)
2170 int name_len = strlen(name);
2175 /* create list of variable values */
2176 list = xmalloc(sizeof(*list));
2177 for (i = 0; inp[i]; i++) {
2178 p3 = insert_var_value(inp[i]);
2185 p2 = strchr(p1, ' ');
2192 /* we use n + 2 in realloc for list, because we add
2193 * new element and then we will add NULL element */
2194 list = xrealloc(list, sizeof(*list) * (n + 2));
2195 list[n] = xmalloc(2 + name_len + len);
2196 strcpy(list[n], name);
2197 strcat(list[n], "=");
2198 strncat(list[n], p1, len);
2199 list[n++][name_len + len + 1] = '\0';
2202 if (p3 != inp[i]) free(p3);
2208 static char *insert_var_value(char *inp)
2210 int res_str_len = 0;
2213 char *p, *res_str = NULL;
2216 while ((p = strchr(inp, SPECIAL_VAR_SYMBOL))) {
2219 res_str = xrealloc(res_str, (res_str_len + len));
2220 strncpy((res_str + res_str_len), inp, len);
2224 p = strchr(inp, SPECIAL_VAR_SYMBOL);
2226 p1 = lookup_param(inp);
2228 len = res_str_len + strlen(p1);
2229 res_str = xrealloc(res_str, (1 + len));
2230 strcpy((res_str + res_str_len), p1);
2233 *p = SPECIAL_VAR_SYMBOL;
2238 res_str = xrealloc(res_str, (1 + res_str_len + strlen(inp)));
2239 strcpy((res_str + res_str_len), inp);
2240 while ((p = strchr(res_str, '\n'))) {
2244 return (res_str == NULL) ? inp : res_str;
2247 /* This is used to get/check local shell variables */
2248 static const char *get_local_var(const char *s)
2250 struct variables *cur;
2254 for (cur = top_vars; cur; cur = cur->next)
2255 if (strcmp(cur->name, s) == 0)
2260 /* This is used to set local shell variables
2261 flg_export == 0 if only local (not exporting) variable
2262 flg_export == 1 if "new" exporting environ
2263 flg_export > 1 if current startup environ (not call putenv()) */
2264 static int set_local_var(const char *s, int flg_export)
2268 struct variables *cur;
2272 /* Assume when we enter this function that we are already in
2273 * NAME=VALUE format. So the first order of business is to
2274 * split 's' on the '=' into 'name' and 'value' */
2275 value = strchr(name, '=');
2276 /*if (value == 0 && ++value == 0) ??? -vda */
2277 if (value == NULL || value[1] == '\0') {
2283 for (cur = top_vars; cur; cur = cur->next) {
2284 if (strcmp(cur->name, name) == 0)
2289 if (strcmp(cur->value, value) == 0) {
2290 if (flg_export > 0 && cur->flg_export == 0)
2291 cur->flg_export = flg_export;
2294 } else if (cur->flg_read_only) {
2295 bb_error_msg("%s: readonly variable", name);
2298 if (flg_export > 0 || cur->flg_export > 1)
2299 cur->flg_export = 1;
2300 free((char*)cur->value);
2302 cur->value = strdup(value);
2305 cur = malloc(sizeof(struct variables));
2309 cur->name = strdup(name);
2314 struct variables *bottom = top_vars;
2315 cur->value = strdup(value);
2317 cur->flg_export = flg_export;
2318 cur->flg_read_only = 0;
2319 while (bottom->next)
2320 bottom = bottom->next;
2326 if (result == 0 && cur->flg_export == 1) {
2328 result = putenv(name);
2331 if (result > 0) /* equivalent to previous set */
2337 static void unset_local_var(const char *name)
2339 struct variables *cur, *next;
2343 for (cur = top_vars; cur; cur = cur->next) {
2344 if (strcmp(cur->name, name) == 0) {
2345 if (cur->flg_read_only) {
2346 bb_error_msg("%s: readonly variable", name);
2349 if (cur->flg_export)
2350 unsetenv(cur->name);
2351 free((char*)cur->name);
2352 free((char*)cur->value);
2354 while (next->next != cur)
2356 next->next = cur->next;
2363 static int is_assignment(const char *s)
2365 if (!s || !isalpha(*s))
2368 while (isalnum(*s) || *s == '_')
2373 /* the src parameter allows us to peek forward to a possible &n syntax
2374 * for file descriptor duplication, e.g., "2>&1".
2375 * Return code is 0 normally, 1 if a syntax error is detected in src.
2376 * Resource errors (in xmalloc) cause the process to exit */
2377 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
2378 struct in_str *input)
2380 struct child_prog *child = ctx->child;
2381 struct redir_struct *redir = child->redirects;
2382 struct redir_struct *last_redir = NULL;
2384 /* Create a new redir_struct and drop it onto the end of the linked list */
2387 redir = redir->next;
2389 redir = xmalloc(sizeof(struct redir_struct));
2391 redir->word.gl_pathv = NULL;
2393 last_redir->next = redir;
2395 child->redirects = redir;
2398 redir->type = style;
2399 redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;
2401 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
2403 /* Check for a '2>&1' type redirect */
2404 redir->dup = redirect_dup_num(input);
2405 if (redir->dup == -2) return 1; /* syntax error */
2406 if (redir->dup != -1) {
2407 /* Erik had a check here that the file descriptor in question
2408 * is legit; I postpone that to "run time"
2409 * A "-" representation of "close me" shows up as a -3 here */
2410 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
2412 /* We do _not_ try to open the file that src points to,
2413 * since we need to return and let src be expanded first.
2414 * Set ctx->pending_redirect, so we know what to do at the
2415 * end of the next parsed word.
2417 ctx->pending_redirect = redir;
2422 static struct pipe *new_pipe(void)
2425 pi = xzalloc(sizeof(struct pipe));
2426 /*pi->num_progs = 0;*/
2427 /*pi->progs = NULL;*/
2428 /*pi->next = NULL;*/
2429 /*pi->followup = 0; invalid */
2431 pi->r_mode = RES_NONE;
2435 static void initialize_context(struct p_context *ctx)
2438 ctx->pending_redirect = NULL;
2440 ctx->list_head = new_pipe();
2441 ctx->pipe = ctx->list_head;
2445 done_command(ctx); /* creates the memory for working child */
2448 /* normal return is 0
2449 * if a reserved word is found, and processed, return 1
2450 * should handle if, then, elif, else, fi, for, while, until, do, done.
2451 * case, function, and select are obnoxious, save those for later.
2453 static int reserved_word(o_string *dest, struct p_context *ctx)
2455 struct reserved_combo {
2460 /* Mostly a list of accepted follow-up reserved words.
2461 * FLAG_END means we are done with the sequence, and are ready
2462 * to turn the compound list into a command.
2463 * FLAG_START means the word must start a new compound list.
2465 static const struct reserved_combo reserved_list[] = {
2466 { "if", RES_IF, FLAG_THEN | FLAG_START },
2467 { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
2468 { "elif", RES_ELIF, FLAG_THEN },
2469 { "else", RES_ELSE, FLAG_FI },
2470 { "fi", RES_FI, FLAG_END },
2471 { "for", RES_FOR, FLAG_IN | FLAG_START },
2472 { "while", RES_WHILE, FLAG_DO | FLAG_START },
2473 { "until", RES_UNTIL, FLAG_DO | FLAG_START },
2474 { "in", RES_IN, FLAG_DO },
2475 { "do", RES_DO, FLAG_DONE },
2476 { "done", RES_DONE, FLAG_END }
2478 enum { NRES = sizeof(reserved_list)/sizeof(reserved_list[0]) };
2479 const struct reserved_combo *r;
2481 for (r = reserved_list; r < reserved_list+NRES; r++) {
2482 if (strcmp(dest->data, r->literal) == 0) {
2483 debug_printf("found reserved word %s, code %d\n", r->literal, r->code);
2484 if (r->flag & FLAG_START) {
2485 struct p_context *new = xmalloc(sizeof(struct p_context));
2486 debug_printf("push stack\n");
2487 if (ctx->w == RES_IN || ctx->w == RES_FOR) {
2494 *new = *ctx; /* physical copy */
2495 initialize_context(ctx);
2497 } else if (ctx->w == RES_NONE || !(ctx->old_flag & (1 << r->code))) {
2504 ctx->old_flag = r->flag;
2505 if (ctx->old_flag & FLAG_END) {
2506 struct p_context *old;
2507 debug_printf("pop stack\n");
2508 done_pipe(ctx, PIPE_SEQ);
2510 old->child->group = ctx->list_head;
2511 old->child->subshell = 0;
2512 *ctx = *old; /* physical copy */
2522 /* normal return is 0.
2523 * Syntax or xglob errors return 1. */
2524 static int done_word(o_string *dest, struct p_context *ctx)
2526 struct child_prog *child = ctx->child;
2527 glob_t *glob_target;
2530 debug_printf("done_word: %s %p\n", dest->data, child);
2531 if (dest->length == 0 && !dest->nonnull) {
2532 debug_printf(" true null, ignored\n");
2535 if (ctx->pending_redirect) {
2536 glob_target = &ctx->pending_redirect->word;
2540 return 1; /* syntax error, groups and arglists don't mix */
2542 if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) {
2543 debug_printf("checking %s for reserved-ness\n", dest->data);
2544 if (reserved_word(dest, ctx))
2545 return (ctx->w == RES_SNTX);
2547 glob_target = &child->glob_result;
2548 if (child->argv) flags |= GLOB_APPEND;
2550 gr = xglob(dest, flags, glob_target);
2551 if (gr != 0) return 1;
2554 if (ctx->pending_redirect) {
2555 ctx->pending_redirect = NULL;
2556 if (glob_target->gl_pathc != 1) {
2557 bb_error_msg("ambiguous redirect");
2561 child->argv = glob_target->gl_pathv;
2563 if (ctx->w == RES_FOR) {
2564 done_word(dest, ctx);
2565 done_pipe(ctx, PIPE_SEQ);
2570 /* The only possible error here is out of memory, in which case
2572 static int done_command(struct p_context *ctx)
2574 /* The child is really already in the pipe structure, so
2575 * advance the pipe counter and make a new, null child.
2576 * Only real trickiness here is that the uncommitted
2577 * child structure, to which ctx->child points, is not
2578 * counted in pi->num_progs. */
2579 struct pipe *pi = ctx->pipe;
2580 struct child_prog *prog = ctx->child;
2582 if (prog && prog->group == NULL
2583 && prog->argv == NULL
2584 && prog->redirects == NULL
2586 debug_printf("done_command: skipping null command\n");
2591 debug_printf("done_command: num_progs incremented to %d\n", pi->num_progs);
2593 debug_printf("done_command: initializing\n");
2595 pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2597 prog = pi->progs + pi->num_progs;
2598 memset(prog, 0, sizeof(*prog));
2599 /*prog->redirects = NULL;*/
2600 /*prog->argv = NULL; */
2601 /*prog->is_stopped = 0;*/
2602 /*prog->group = NULL;*/
2603 /*prog->glob_result.gl_pathv = NULL;*/
2607 prog->type = ctx->type;
2609 /* but ctx->pipe and ctx->list_head remain unchanged */
2613 static int done_pipe(struct p_context *ctx, pipe_style type)
2616 done_command(ctx); /* implicit closure of previous command */
2617 debug_printf("done_pipe, type %d\n", type);
2618 ctx->pipe->followup = type;
2619 ctx->pipe->r_mode = ctx->w;
2621 ctx->pipe->next = new_p;
2624 done_command(ctx); /* set up new pipe to accept commands */
2628 /* peek ahead in the in_str to find out if we have a "&n" construct,
2629 * as in "2>&1", that represents duplicating a file descriptor.
2630 * returns either -2 (syntax error), -1 (no &), or the number found.
2632 static int redirect_dup_num(struct in_str *input)
2634 int ch, d = 0, ok = 0;
2636 if (ch != '&') return -1;
2638 b_getch(input); /* get the & */
2642 return -3; /* "-" represents "close me" */
2644 while (isdigit(ch)) {
2645 d = d*10 + (ch-'0');
2652 bb_error_msg("ambiguous redirect");
2656 /* If a redirect is immediately preceded by a number, that number is
2657 * supposed to tell which file descriptor to redirect. This routine
2658 * looks for such preceding numbers. In an ideal world this routine
2659 * needs to handle all the following classes of redirects...
2660 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
2661 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
2662 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
2663 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
2664 * A -1 output from this program means no valid number was found, so the
2665 * caller should use the appropriate default for this redirection.
2667 static int redirect_opt_num(o_string *o)
2673 for (num = 0; num < o->length; num++) {
2674 if (!isdigit(*(o->data + num))) {
2678 /* reuse num (and save an int) */
2679 num = atoi(o->data);
2684 static FILE *generate_stream_from_list(struct pipe *head)
2687 int pid, channel[2];
2688 if (pipe(channel) < 0) bb_perror_msg_and_die("pipe");
2695 bb_perror_msg_and_die("fork");
2696 } else if (pid == 0) {
2698 if (channel[1] != 1) {
2699 dup2(channel[1], 1);
2702 _exit(run_list_real(head)); /* leaks memory */
2704 debug_printf("forked child %d\n", pid);
2706 pf = fdopen(channel[0], "r");
2707 debug_printf("pipe on FILE *%p\n", pf);
2711 /* this version hacked for testing purposes */
2712 /* return code is exit status of the process that is run. */
2713 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2716 o_string result = NULL_O_STRING;
2717 struct p_context inner;
2719 struct in_str pipe_str;
2720 initialize_context(&inner);
2722 /* recursion to generate command */
2723 retcode = parse_stream(&result, &inner, input, subst_end);
2724 if (retcode != 0) return retcode; /* syntax error or EOF */
2725 done_word(&result, &inner);
2726 done_pipe(&inner, PIPE_SEQ);
2729 p = generate_stream_from_list(inner.list_head);
2730 if (p == NULL) return 1;
2731 mark_open(fileno(p));
2732 setup_file_in_str(&pipe_str, p);
2734 /* now send results of command back into original context */
2735 retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2736 /* XXX In case of a syntax error, should we try to kill the child?
2737 * That would be tough to do right, so just read until EOF. */
2739 while (b_getch(&pipe_str) != EOF)
2743 debug_printf("done reading from pipe, pclose()ing\n");
2744 /* This is the step that wait()s for the child. Should be pretty
2745 * safe, since we just read an EOF from its stdout. We could try
2746 * to better, by using wait(), and keeping track of background jobs
2747 * at the same time. That would be a lot of work, and contrary
2748 * to the KISS philosophy of this program. */
2749 mark_closed(fileno(p));
2750 retcode = pclose(p);
2751 free_pipe_list(inner.list_head, 0);
2752 debug_printf("pclosed, retcode=%d\n", retcode);
2753 /* XXX this process fails to trim a single trailing newline */
2757 static int parse_group(o_string *dest, struct p_context *ctx,
2758 struct in_str *input, int ch)
2760 int rcode, endch = 0;
2761 struct p_context sub;
2762 struct child_prog *child = ctx->child;
2765 return 1; /* syntax error, groups and arglists don't mix */
2767 initialize_context(&sub);
2771 child->subshell = 1;
2777 syntax(); /* really logic error */
2779 rcode = parse_stream(dest, &sub, input, endch);
2780 done_word(dest, &sub); /* finish off the final word in the subcontext */
2781 done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
2782 child->group = sub.list_head;
2784 /* child remains "open", available for possible redirects */
2787 /* basically useful version until someone wants to get fancier,
2788 * see the bash man page under "Parameter Expansion" */
2789 static const char *lookup_param(const char *src)
2791 const char *p = NULL;
2795 p = get_local_var(src);
2800 /* Make new string for parser */
2801 static char* make_string(char ** inp)
2808 for (n = 0; inp[n]; n++) {
2809 p = insert_var_value(inp[n]);
2810 str = xrealloc(str, (len + strlen(p)));
2817 len = strlen(str) + 3;
2818 if (p != inp[n]) free(p);
2826 /* return code: 0 for OK, 1 for syntax error */
2827 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2831 int ch = input->peek(input); /* first character after the $ */
2832 debug_printf("handle_dollar: ch=%c\n", ch);
2834 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2836 while (ch = b_peek(input), isalnum(ch) || ch == '_') {
2840 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2841 } else if (isdigit(ch)) {
2842 i = ch - '0'; /* XXX is $0 special? */
2843 if (i < global_argc) {
2844 parse_string(dest, ctx, global_argv[i]); /* recursion */
2847 } else switch (ch) {
2849 b_adduint(dest, getpid());
2853 if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2857 b_adduint(dest, last_return_code);
2861 b_adduint(dest, global_argc ? global_argc-1 : 0);
2865 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2868 /* XXX maybe someone will try to escape the '}' */
2870 ch = b_getch(input);
2871 if (ch == EOF || ch == '}')
2879 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2883 process_command_subs(dest, ctx, input, ')');
2887 for (i = 1; i < global_argc; i++) {
2888 parse_string(dest, ctx, global_argv[i]);
2889 if (i+1 < global_argc)
2890 parse_string(dest, ctx, sep);
2896 /* still unhandled, but should be eventually */
2897 bb_error_msg("unhandled syntax: $%c", ch);
2901 b_addqchr(dest,'$', dest->quote);
2903 /* Eat the character if the flag was set. If the compiler
2904 * is smart enough, we could substitute "b_getch(input);"
2905 * for all the "advance = 1;" above, and also end up with
2906 * a nice size-optimized program. Hah! That'll be the day.
2908 if (advance) b_getch(input);
2912 static int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2915 setup_string_in_str(&foo, src);
2916 return parse_stream(dest, ctx, &foo, '\0');
2919 /* return code is 0 for normal exit, 1 for syntax error */
2920 static int parse_stream(o_string *dest, struct p_context *ctx,
2921 struct in_str *input, int end_trigger)
2925 redir_type redir_style;
2928 /* Only double-quote state is handled in the state variable dest->quote.
2929 * A single-quote triggers a bypass of the main loop until its mate is
2930 * found. When recursing, quote state is passed in via dest->quote. */
2932 debug_printf("parse_stream, end_trigger=%d\n", end_trigger);
2933 while ((ch = b_getch(input)) != EOF) {
2935 next = (ch == '\n') ? 0 : b_peek(input);
2936 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2937 ch, ch, m, dest->quote);
2938 if (m == 0 || ((m == 1 || m == 2) && dest->quote)) {
2939 b_addqchr(dest, ch, dest->quote);
2942 if (m == 2) { /* unquoted IFS */
2943 if (done_word(dest, ctx)) {
2946 /* If we aren't performing a substitution, treat a newline as a
2947 * command separator. */
2948 if (end_trigger != '\0' && ch == '\n')
2949 done_pipe(ctx, PIPE_SEQ);
2951 if (ch == end_trigger && !dest->quote && ctx->w == RES_NONE) {
2952 debug_printf("leaving parse_stream (triggered)\n");
2959 if (dest->length == 0 && !dest->quote) {
2962 if (ch == EOF || ch == '\n')
2967 b_addqchr(dest, ch, dest->quote);
2975 b_addqchr(dest, '\\', dest->quote);
2976 b_addqchr(dest, b_getch(input), dest->quote);
2979 if (handle_dollar(dest, ctx, input) != 0) return 1;
2984 ch = b_getch(input);
2985 if (ch == EOF || ch == '\'')
2996 dest->quote = !dest->quote;
2999 process_command_subs(dest, ctx, input, '`');
3002 redir_fd = redirect_opt_num(dest);
3003 done_word(dest, ctx);
3004 redir_style = REDIRECT_OVERWRITE;
3006 redir_style = REDIRECT_APPEND;
3008 } else if (next == '(') {
3009 syntax(); /* until we support >(list) Process Substitution */
3012 setup_redirect(ctx, redir_fd, redir_style, input);
3015 redir_fd = redirect_opt_num(dest);
3016 done_word(dest, ctx);
3017 redir_style = REDIRECT_INPUT;
3019 redir_style = REDIRECT_HEREIS;
3021 } else if (next == '>') {
3022 redir_style = REDIRECT_IO;
3024 } else if (next == '(') {
3025 syntax(); /* until we support <(list) Process Substitution */
3028 setup_redirect(ctx, redir_fd, redir_style, input);
3031 done_word(dest, ctx);
3032 done_pipe(ctx, PIPE_SEQ);
3035 done_word(dest, ctx);
3038 done_pipe(ctx, PIPE_AND);
3040 done_pipe(ctx, PIPE_BG);
3044 done_word(dest, ctx);
3047 done_pipe(ctx, PIPE_OR);
3049 /* we could pick up a file descriptor choice here
3050 * with redirect_opt_num(), but bash doesn't do it.
3051 * "echo foo 2| cat" yields "foo 2". */
3057 if (parse_group(dest, ctx, input, ch) != 0)
3062 syntax(); /* Proper use of this character caught by end_trigger */
3065 syntax(); /* this is really an internal logic error */
3069 /* complain if quote? No, maybe we just finished a command substitution
3070 * that was quoted. Example:
3071 * $ echo "`cat foo` plus more"
3072 * and we just got the EOF generated by the subshell that ran "cat foo"
3073 * The only real complaint is if we got an EOF when end_trigger != '\0',
3074 * that is, we were really supposed to get end_trigger, and never got
3075 * one before the EOF. Can't use the standard "syntax error" return code,
3076 * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
3077 debug_printf("leaving parse_stream (EOF)\n");
3078 if (end_trigger != '\0')
3083 static void mapset(const char *set, int code)
3086 map[(unsigned char)*set++] = code;
3089 static void update_ifs_map(void)
3091 /* char *ifs and char map[256] are both globals. */
3092 ifs = getenv("IFS");
3093 if (ifs == NULL) ifs = " \t\n";
3094 /* Precompute a list of 'flow through' behavior so it can be treated
3095 * quickly up front. Computation is necessary because of IFS.
3096 * Special case handling of IFS == " \t\n" is not implemented.
3097 * The map[] array only really needs two bits each, and on most machines
3098 * that would be faster because of the reduced L1 cache footprint.
3100 memset(map, 0, sizeof(map)); /* most characters flow through always */
3101 mapset("\\$'\"`", 3); /* never flow through */
3102 mapset("<>;&|(){}#", 1); /* flow through if quoted */
3103 mapset(ifs, 2); /* also flow through if quoted */
3106 /* most recursion does not come through here, the exception is
3107 * from builtin_source() */
3108 static int parse_stream_outer(struct in_str *inp, int flag)
3110 // FIXME: 'true | exit 3; echo $?' is parsed as a whole,
3111 // as a result $? is replaced by 0, not 3!
3112 // Need to stop & execute stuff at ';', not parse till EOL!
3114 struct p_context ctx;
3115 o_string temp = NULL_O_STRING;
3119 initialize_context(&ctx);
3121 if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING))
3123 #if ENABLE_HUSH_INTERACTIVE
3124 inp->promptmode = 1;
3126 rcode = parse_stream(&temp, &ctx, inp, '\n');
3127 if (rcode != 1 && ctx.old_flag != 0) {
3130 if (rcode != 1 && ctx.old_flag == 0) {
3131 done_word(&temp, &ctx);
3132 done_pipe(&ctx, PIPE_SEQ);
3133 debug_printf_exec("parse_stream_outer: run_list\n");
3134 run_list(ctx.list_head);
3136 if (ctx.old_flag != 0) {
3143 free_pipe_list(ctx.list_head, 0);
3146 } while (rcode != -1 && !(flag & FLAG_EXIT_FROM_LOOP)); /* loop on syntax errors, return on EOF */
3150 static int parse_string_outer(const char *s, int flag)
3152 struct in_str input;
3153 setup_string_in_str(&input, s);
3154 return parse_stream_outer(&input, flag);
3157 static int parse_file_outer(FILE *f)
3160 struct in_str input;
3161 setup_file_in_str(&input, f);
3162 rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON);
3167 /* Make sure we have a controlling tty. If we get started under a job
3168 * aware app (like bash for example), make sure we are now in charge so
3169 * we don't fight over who gets the foreground */
3170 static void setup_job_control(void)
3174 saved_task_pgrp = shell_pgrp = getpgrp();
3175 debug_printf("saved_task_pgrp=%d\n", saved_task_pgrp);
3176 fcntl(interactive_fd, F_SETFD, FD_CLOEXEC);
3178 /* If we were ran as 'hush &',
3179 * sleep until we are in the foreground. */
3180 while (tcgetpgrp(interactive_fd) != shell_pgrp) {
3181 /* Send TTIN to ourself (should stop us) */
3182 kill(- shell_pgrp, SIGTTIN);
3183 shell_pgrp = getpgrp();
3186 /* Ignore job-control and misc signals. */
3187 set_jobctrl_sighandler(SIG_IGN);
3188 set_misc_sighandler(SIG_IGN);
3189 //huh? signal(SIGCHLD, SIG_IGN);
3191 /* We _must_ restore tty pgrp fatal signals */
3192 set_fatal_sighandler(sigexit);
3194 /* Put ourselves in our own process group. */
3195 setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
3196 /* Grab control of the terminal. */
3197 tcsetpgrp(interactive_fd, getpid());
3201 int hush_main(int argc, char **argv);
3202 int hush_main(int argc, char **argv)
3208 #if ENABLE_FEATURE_EDITING
3209 line_input_state = new_line_input_t(FOR_SHELL);
3212 /* XXX what should these be while sourcing /etc/profile? */
3216 /* (re?) initialize globals. Sometimes hush_main() ends up calling
3217 * hush_main(), therefore we cannot rely on the BSS to zero out this
3218 * stuff. Reset these to 0 every time. */
3220 /* map[] is taken care of with call to update_ifs_map() */
3222 close_me_head = NULL;
3223 #if ENABLE_HUSH_INTERACTIVE
3232 /* Initialize some more globals to non-zero values */
3234 #if ENABLE_HUSH_INTERACTIVE
3235 #if ENABLE_FEATURE_EDITING
3236 cmdedit_set_initial_prompt();
3242 /* initialize our shell local variables with the values
3243 * currently living in the environment */
3247 set_local_var(*e++, 2); /* without call putenv() */
3249 last_return_code = EXIT_SUCCESS;
3251 if (argv[0] && argv[0][0] == '-') {
3252 debug_printf("\nsourcing /etc/profile\n");
3253 input = fopen("/etc/profile", "r");
3254 if (input != NULL) {
3255 mark_open(fileno(input));
3256 parse_file_outer(input);
3257 mark_closed(fileno(input));
3263 while ((opt = getopt(argc, argv, "c:xif")) > 0) {
3266 global_argv = argv + optind;
3267 global_argc = argc - optind;
3268 opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON);
3271 // Well, we cannot just declare interactiveness,
3272 // we have to have some stuff (ctty, etc)
3273 /*interactive_fd++;*/
3280 fprintf(stderr, "Usage: sh [FILE]...\n"
3281 " or: sh -c command [args]...\n\n");
3289 /* A shell is interactive if the '-i' flag was given, or if all of
3290 * the following conditions are met:
3292 * no arguments remaining or the -s flag given
3293 * standard input is a terminal
3294 * standard output is a terminal
3295 * Refer to Posix.2, the description of the 'sh' utility. */
3296 if (argv[optind] == NULL && input == stdin
3297 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
3299 saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
3300 debug_printf("saved_tty_pgrp=%d\n", saved_tty_pgrp);
3301 if (saved_tty_pgrp >= 0) {
3302 /* try to dup to high fd#, >= 255 */
3303 interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
3304 if (interactive_fd < 0) {
3305 /* try to dup to any fd */
3306 interactive_fd = dup(STDIN_FILENO);
3307 if (interactive_fd < 0)
3311 // TODO: track & disallow any attempts of user
3312 // to (inadvertently) close/redirect it
3315 debug_printf("\ninteractive_fd=%d\n", interactive_fd);
3316 if (interactive_fd) {
3317 /* Looks like they want an interactive shell */
3318 setup_job_control();
3319 /* Make xfuncs do cleanup on exit */
3320 die_sleep = -1; /* flag */
3321 if (setjmp(die_jmp)) {
3322 /* xfunc has failed! die die die */
3323 hush_exit(xfunc_error_retval);
3325 #if !ENABLE_FEATURE_SH_EXTRA_QUIET
3326 printf("\n\n%s hush - the humble shell v"HUSH_VER_STR"\n", BB_BANNER);
3327 printf("Enter 'help' for a list of built-in commands.\n\n");
3330 #elif ENABLE_HUSH_INTERACTIVE
3331 /* no job control compiled, only prompt/line editing */
3332 if (argv[optind] == NULL && input == stdin
3333 && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
3335 interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
3336 if (interactive_fd < 0) {
3337 /* try to dup to any fd */
3338 interactive_fd = dup(STDIN_FILENO);
3339 if (interactive_fd < 0)
3347 if (argv[optind] == NULL) {
3348 opt = parse_file_outer(stdin);
3352 debug_printf("\nrunning script '%s'\n", argv[optind]);
3353 global_argv = argv + optind;
3354 global_argc = argc - optind;
3355 input = xfopen(argv[optind], "r");
3356 opt = parse_file_outer(input);
3358 #if ENABLE_FEATURE_CLEAN_UP
3360 if (cwd != bb_msg_unknown)
3363 struct variables *cur, *tmp;
3364 for (cur = top_vars; cur; cur = tmp) {
3366 if (!cur->flg_read_only) {
3367 free((char*)cur->name);
3368 free((char*)cur->value);
3376 hush_exit(opt ? opt : last_return_code);