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.
13 * The execution engine, the builtins, and much of the underlying
14 * support has been adapted from busybox-0.49pre's lash,
15 * which is Copyright (C) 2000 by Lineo, Inc., and
16 * written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>.
17 * That, in turn, is based in part on ladsh.c, by Michael K. Johnson and
18 * Erik W. Troan, which they placed in the public domain. I don't know
19 * how much of the Johnson/Troan code has survived the repeated rewrites.
21 * simple_itoa() was lifted from boa-0.93.15
22 * b_addchr() derived from similar w_addchar function in glibc-2.2
23 * setup_redirect(), redirect_opt_num(), and big chunks of main()
24 * and many builtins derived from contributions by Erik Andersen
25 * miscellaneous bugfixes from Matt Kraai
27 * There are two big (and related) architecture differences between
28 * this parser and the lash parser. One is that this version is
29 * actually designed from the ground up to understand nearly all
30 * of the Bourne grammar. The second, consequential change is that
31 * the parser and input reader have been turned inside out. Now,
32 * the parser is in control, and asks for input as needed. The old
33 * way had the input reader in control, and it asked for parsing to
34 * take place as needed. The new way makes it much easier to properly
35 * handle the recursion implicit in the various substitutions, especially
36 * across continuation lines.
38 * Bash grammar not implemented: (how many of these were in original sh?)
39 * $@ (those sure look like weird quoting rules)
41 * ! negation operator for pipes
42 * &> and >& redirection of stdout+stderr
45 * fancy forms of Parameter Expansion
47 * Arithmetic Expansion
48 * <(list) and >(list) Process Substitution
49 * reserved words: case, esac, select, function
50 * Here Documents ( << word )
53 * job handling woefully incomplete and buggy
54 * reserved word execution woefully incomplete and buggy
56 * port selected bugfixes from post-0.49 busybox lash - done?
57 * finish implementing reserved words: for, while, until, do, done
58 * change { and } from special chars to reserved words
59 * builtins: break, continue, eval, return, set, trap, ulimit
61 * handle children going into background
62 * clean up recognition of null pipes
63 * check setting of global_argc and global_argv
64 * control-C handling, probably with longjmp
65 * follow IFS rules more precisely, including update semantics
66 * figure out what to do with backslash-newline
67 * explain why we use signal instead of sigaction
68 * propagate syntax errors, die on resource errors?
69 * continuation lines, both explicit and implicit - done?
70 * memory leak finding and plugging - done?
71 * more testing, especially quoting rules and redirection
72 * document how quoting rules not precisely followed for variable assignments
73 * maybe change map[] to use 2-bit entries
74 * (eventually) remove all the printf's
76 * This program is free software; you can redistribute it and/or modify
77 * it under the terms of the GNU General Public License as published by
78 * the Free Software Foundation; either version 2 of the License, or
79 * (at your option) any later version.
81 * This program is distributed in the hope that it will be useful,
82 * but WITHOUT ANY WARRANTY; without even the implied warranty of
83 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
84 * General Public License for more details.
86 * You should have received a copy of the GNU General Public License
87 * along with this program; if not, write to the Free Software
88 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
90 #include <ctype.h> /* isalpha, isdigit */
91 #include <unistd.h> /* getpid */
92 #include <stdlib.h> /* getenv, atoi */
93 #include <string.h> /* strchr */
94 #include <stdio.h> /* popen etc. */
95 #include <glob.h> /* glob, of course */
96 #include <stdarg.h> /* va_list */
99 #include <getopt.h> /* should be pretty obvious */
101 #include <sys/stat.h> /* ulimit */
102 #include <sys/types.h>
103 #include <sys/wait.h>
106 /* #include <dmalloc.h> */
107 /* #define DEBUG_SHELL */
113 #define applet_name "hush"
114 #include "standalone.h"
115 #define shell_main main
116 #undef BB_FEATURE_SH_FANCY_PROMPT
121 REDIRECT_OVERWRITE = 2,
127 /* The descrip member of this structure is only used to make debugging
129 struct {int mode; int default_fd; char *descrip;} redir_table[] = {
131 { O_RDONLY, 0, "<" },
132 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
133 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
134 { O_RDONLY, -1, "<<" },
145 /* might eventually control execution */
161 #define FLAG_END (1<<RES_NONE)
162 #define FLAG_IF (1<<RES_IF)
163 #define FLAG_THEN (1<<RES_THEN)
164 #define FLAG_ELIF (1<<RES_ELIF)
165 #define FLAG_ELSE (1<<RES_ELSE)
166 #define FLAG_FI (1<<RES_FI)
167 #define FLAG_FOR (1<<RES_FOR)
168 #define FLAG_WHILE (1<<RES_WHILE)
169 #define FLAG_UNTIL (1<<RES_UNTIL)
170 #define FLAG_DO (1<<RES_DO)
171 #define FLAG_DONE (1<<RES_DONE)
172 #define FLAG_START (1<<RES_XXXX)
174 /* This holds pointers to the various results of parsing */
176 struct child_prog *child;
177 struct pipe *list_head;
179 struct redir_struct *pending_redirect;
181 int old_flag; /* for figuring out valid reserved words */
182 struct p_context *stack;
183 /* How about quoting status? */
186 struct redir_struct {
187 redir_type type; /* type of redirection */
188 int fd; /* file descriptor being redirected */
189 int dup; /* -1, or file descriptor being duplicated */
190 struct redir_struct *next; /* pointer to the next redirect in the list */
191 glob_t word; /* *word.gl_pathv is the filename */
195 pid_t pid; /* 0 if exited */
196 char **argv; /* program name and arguments */
197 struct pipe *group; /* if non-NULL, first in group or subshell */
198 int subshell; /* flag, non-zero if group must be forked */
199 struct redir_struct *redirects; /* I/O redirections */
200 glob_t glob_result; /* result of parameter globbing */
201 int is_stopped; /* is the program currently running? */
202 struct pipe *family; /* pointer back to the child's parent pipe */
206 int jobid; /* job number */
207 int num_progs; /* total number of programs in job */
208 int running_progs; /* number of programs running */
209 char *text; /* name of job */
210 char *cmdbuf; /* buffer various argv's point into */
211 pid_t pgrp; /* process group ID for the job */
212 struct child_prog *progs; /* array of commands in pipe */
213 struct pipe *next; /* to track background commands */
214 int stopped_progs; /* number of programs alive, but stopped */
215 int job_context; /* bitmask defining current context */
216 pipe_style followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
217 reserved_style r_mode; /* supports if, for, while, until */
221 struct pipe *head; /* head of list of running jobs */
222 struct pipe *fg; /* current foreground job */
227 struct close_me *next;
235 struct variables *next;
238 /* globals, connect us to the outside world
239 * the first three support $?, $#, and $1 */
241 unsigned int global_argc;
242 unsigned int last_return_code;
243 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
245 /* Variables we export */
246 unsigned int shell_context; /* Used in cmdedit.c to reset the
247 * context when someone hits ^C */
249 /* "globals" within this file */
251 static char map[256];
252 static int fake_mode;
253 static int interactive;
254 static struct close_me *close_me_head;
255 static const char *cwd;
256 static struct jobset *job_list;
257 static unsigned int last_bg_pid;
260 struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
261 struct variables *top_vars = &shell_ver;
263 #define B_CHUNK (100)
273 #define NULL_O_STRING {NULL,0,0,0,0}
274 /* used for initialization:
275 o_string foo = NULL_O_STRING; */
277 /* I can almost use ordinary FILE *. Is open_memstream() universally
278 * available? Where is it documented? */
284 int (*get) (struct in_str *);
285 int (*peek) (struct in_str *);
287 #define b_getch(input) ((input)->get(input))
288 #define b_peek(input) ((input)->peek(input))
290 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
292 struct built_in_command {
293 char *cmd; /* name */
294 char *descr; /* description */
295 int (*function) (struct child_prog *); /* function ptr */
298 /* belongs in busybox.h */
299 static inline int max(int a, int b) {
303 /* This should be in utility.c */
305 static void debug_printf(const char *format, ...)
308 va_start(args, format);
309 vfprintf(stderr, format, args);
313 static inline void debug_printf(const char *format, ...) { }
315 #define final_printf debug_printf
317 static void __syntax(char *file, int line) {
318 error_msg("syntax error %s:%d", file, line);
320 #define syntax() __syntax(__FILE__, __LINE__)
322 /* Index of subroutines: */
323 /* function prototypes for builtins */
324 static int builtin_cd(struct child_prog *child);
325 static int builtin_env(struct child_prog *child);
326 static int builtin_exec(struct child_prog *child);
327 static int builtin_exit(struct child_prog *child);
328 static int builtin_export(struct child_prog *child);
329 static int builtin_fg_bg(struct child_prog *child);
330 static int builtin_help(struct child_prog *child);
331 static int builtin_jobs(struct child_prog *child);
332 static int builtin_pwd(struct child_prog *child);
333 static int builtin_read(struct child_prog *child);
334 static int builtin_set(struct child_prog *child);
335 static int builtin_shift(struct child_prog *child);
336 static int builtin_source(struct child_prog *child);
337 static int builtin_umask(struct child_prog *child);
338 static int builtin_unset(struct child_prog *child);
339 static int builtin_not_written(struct child_prog *child);
340 /* o_string manipulation: */
341 static int b_check_space(o_string *o, int len);
342 static int b_addchr(o_string *o, int ch);
343 static void b_reset(o_string *o);
344 static int b_addqchr(o_string *o, int ch, int quote);
345 static int b_adduint(o_string *o, unsigned int i);
346 /* in_str manipulations: */
347 static int static_get(struct in_str *i);
348 static int static_peek(struct in_str *i);
349 static int file_get(struct in_str *i);
350 static int file_peek(struct in_str *i);
351 static void setup_file_in_str(struct in_str *i, FILE *f);
352 static void setup_string_in_str(struct in_str *i, const char *s);
353 /* close_me manipulations: */
354 static void mark_open(int fd);
355 static void mark_closed(int fd);
356 static void close_all();
357 /* "run" the final data structures: */
358 static char *indenter(int i);
359 static int run_list_test(struct pipe *head, int indent);
360 static int run_pipe_test(struct pipe *pi, int indent);
361 /* really run the final data structures: */
362 static int setup_redirects(struct child_prog *prog, int squirrel[]);
363 static int pipe_wait(struct pipe *pi);
364 static int run_list_real(struct pipe *pi);
365 static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
366 int controlling_tty(int check_pgrp);
367 static int run_pipe_real(struct pipe *pi);
368 /* extended glob support: */
369 static int globhack(const char *src, int flags, glob_t *pglob);
370 static int glob_needed(const char *s);
371 static int xglob(o_string *dest, int flags, glob_t *pglob);
372 /* variable assignment: */
373 static int is_assignment(const char *s);
374 /* data structure manipulation: */
375 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
376 static void initialize_context(struct p_context *ctx);
377 static int done_word(o_string *dest, struct p_context *ctx);
378 static int done_command(struct p_context *ctx);
379 static int done_pipe(struct p_context *ctx, pipe_style type);
380 /* primary string parsing: */
381 static int redirect_dup_num(struct in_str *input);
382 static int redirect_opt_num(o_string *o);
383 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
384 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
385 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src);
386 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
387 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
388 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
390 static int parse_stream_outer(struct in_str *inp);
391 static int parse_string_outer(const char *s);
392 static int parse_file_outer(FILE *f);
393 /* job management: */
394 static void checkjobs();
395 static void insert_bg_job(struct pipe *pi);
396 static void remove_bg_job(struct pipe *pi);
397 static void free_pipe(struct pipe *pi);
398 /* local variable support */
399 static char *get_local_var(const char *var);
400 static void unset_local_var(const char *name);
401 static int set_local_var(const char *s, int flg_export);
404 /* Table of built-in functions. They can be forked or not, depending on
405 * context: within pipes, they fork. As simple commands, they do not.
406 * When used in non-forking context, they can change global variables
407 * in the parent shell process. If forked, of course they can not.
408 * For example, 'unset foo | whatever' will parse and run, but foo will
409 * still be set at the end. */
410 static struct built_in_command bltins[] = {
411 {"bg", "Resume a job in the background", builtin_fg_bg},
412 {"break", "Exit for, while or until loop", builtin_not_written},
413 {"cd", "Change working directory", builtin_cd},
414 {"continue", "Continue for, while or until loop", builtin_not_written},
415 {"env", "Print all environment variables", builtin_env},
416 {"eval", "Construct and run shell command", builtin_not_written},
417 {"exec", "Exec command, replacing this shell with the exec'd process",
419 {"exit", "Exit from shell()", builtin_exit},
420 {"export", "Set environment variable", builtin_export},
421 {"fg", "Bring job into the foreground", builtin_fg_bg},
422 {"jobs", "Lists the active jobs", builtin_jobs},
423 {"pwd", "Print current directory", builtin_pwd},
424 {"read", "Input environment variable", builtin_read},
425 {"return", "Return from a function", builtin_not_written},
426 {"set", "Set/unset shell local variables", builtin_set},
427 {"shift", "Shift positional parameters", builtin_shift},
428 {"trap", "Trap signals", builtin_not_written},
429 {"ulimit","Controls resource limits", builtin_not_written},
430 {"umask","Sets file creation mask", builtin_umask},
431 {"unset", "Unset environment variable", builtin_unset},
432 {".", "Source-in and run commands in a file", builtin_source},
433 {"help", "List shell built-in commands", builtin_help},
437 static const char *set_cwd(void)
440 cwd = NULL; /* xgetcwd(arg) called free(arg) */
441 cwd = xgetcwd((char *)cwd);
448 /* built-in 'cd <path>' handler */
449 static int builtin_cd(struct child_prog *child)
452 if (child->argv[1] == NULL)
453 newdir = getenv("HOME");
455 newdir = child->argv[1];
457 printf("cd: %s: %s\n", newdir, strerror(errno));
464 /* built-in 'env' handler */
465 static int builtin_env(struct child_prog *dummy)
468 if (e == NULL) return EXIT_FAILURE;
475 /* built-in 'exec' handler */
476 static int builtin_exec(struct child_prog *child)
478 if (child->argv[1] == NULL)
479 return EXIT_SUCCESS; /* Really? */
485 /* built-in 'exit' handler */
486 static int builtin_exit(struct child_prog *child)
488 if (child->argv[1] == NULL)
489 exit(last_return_code);
490 exit (atoi(child->argv[1]));
493 /* built-in 'export VAR=value' handler */
494 static int builtin_export(struct child_prog *child)
497 char *name = child->argv[1];
500 return (builtin_env(child));
506 char *value = strchr(name, '=');
510 /* They are exporting something without an =VALUE */
512 value = get_local_var(name);
514 size_t ln = strlen(name);
516 tmp = realloc(name, ln+strlen(value)+2);
520 sprintf(tmp+ln, "=%s", value);
524 /* bash does not return an error when trying to export
525 * an undefined variable. Do likewise. */
531 perror_msg("export");
533 res = set_local_var(name, 1);
540 /* built-in 'fg' and 'bg' handler */
541 static int builtin_fg_bg(struct child_prog *child)
544 struct pipe *pi=NULL;
546 /* If they gave us no args, assume they want the last backgrounded task */
547 if (!child->argv[1]) {
548 for (pi = job_list->head; pi; pi = pi->next) {
549 if (pi->progs && pi->progs->pid == last_bg_pid) {
554 error_msg("%s: no current job", child->argv[0]);
558 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
559 error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
563 for (pi = job_list->head; pi; pi = pi->next) {
564 if (pi->jobid == jobnum) {
569 error_msg("%s: %d: no such job", child->argv[0], jobnum);
573 if (*child->argv[0] == 'f') {
574 /* Make this job the foreground job */
575 signal(SIGTTOU, SIG_IGN);
576 /* suppress messages when run from /linuxrc mag@sysgo.de */
577 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
578 perror_msg("tcsetpgrp-1");
579 signal(SIGTTOU, SIG_DFL);
583 /* Restart the processes in the job */
584 for (i = 0; i < pi->num_progs; i++)
585 pi->progs[i].is_stopped = 0;
587 kill(-pi->pgrp, SIGCONT);
589 pi->stopped_progs = 0;
593 /* built-in 'help' handler */
594 static int builtin_help(struct child_prog *dummy)
596 struct built_in_command *x;
598 printf("\nBuilt-in commands:\n");
599 printf("-------------------\n");
600 for (x = bltins; x->cmd; x++) {
603 printf("%s\t%s\n", x->cmd, x->descr);
609 /* built-in 'jobs' handler */
610 static int builtin_jobs(struct child_prog *child)
615 for (job = job_list->head; job; job = job->next) {
616 if (job->running_progs == job->stopped_progs)
617 status_string = "Stopped";
619 status_string = "Running";
620 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
626 /* built-in 'pwd' handler */
627 static int builtin_pwd(struct child_prog *dummy)
633 /* built-in 'read VAR' handler */
634 static int builtin_read(struct child_prog *child)
638 if (child->argv[1]) {
642 string[0] = 0; /* In case stdin has only EOF */
644 fgets(string, sizeof(string), stdin);
646 var = malloc(strlen(child->argv[1])+strlen(string)+2);
648 sprintf(var, "%s=%s", child->argv[1], string);
649 res = set_local_var(var, 0);
653 fprintf(stderr, "read: %m\n");
654 free(var); /* So not move up to avoid breaking errno */
657 do res=getchar(); while(res!='\n' && res!=EOF);
662 /* built-in 'set VAR=value' handler */
663 static int builtin_set(struct child_prog *child)
665 char *temp = child->argv[1];
669 for(e = top_vars; e; e=e->next)
670 printf("%s=%s\n", e->name, e->value);
672 set_local_var(temp, 0);
678 /* Built-in 'shift' handler */
679 static int builtin_shift(struct child_prog *child)
682 if (child->argv[1]) {
683 n=atoi(child->argv[1]);
685 if (n>=0 && n<global_argc) {
686 /* XXX This probably breaks $0 */
695 /* Built-in '.' handler (read-in and execute commands from file) */
696 static int builtin_source(struct child_prog *child)
701 if (child->argv[1] == NULL)
704 /* XXX search through $PATH is missing */
705 input = fopen(child->argv[1], "r");
707 error_msg("Couldn't open file '%s'", child->argv[1]);
711 /* Now run the file */
712 /* XXX argv and argc are broken; need to save old global_argv
713 * (pointer only is OK!) on this stack frame,
714 * set global_argv=child->argv+1, recurse, and restore. */
715 mark_open(fileno(input));
716 status = parse_file_outer(input);
717 mark_closed(fileno(input));
722 static int builtin_umask(struct child_prog *child)
725 const char *arg = child->argv[1];
728 new_umask=strtoul(arg, &end, 8);
729 if (*end!='\0' || end == arg) {
733 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
739 /* built-in 'unset VAR' handler */
740 static int builtin_unset(struct child_prog *child)
742 /* bash returned already true */
743 unset_local_var(child->argv[1]);
747 static int builtin_not_written(struct child_prog *child)
749 printf("builtin_%s not written\n",child->argv[0]);
753 static int b_check_space(o_string *o, int len)
755 /* It would be easy to drop a more restrictive policy
756 * in here, such as setting a maximum string length */
757 if (o->length + len > o->maxlen) {
758 char *old_data = o->data;
759 /* assert (data == NULL || o->maxlen != 0); */
760 o->maxlen += max(2*len, B_CHUNK);
761 o->data = realloc(o->data, 1 + o->maxlen);
762 if (o->data == NULL) {
766 return o->data == NULL;
769 static int b_addchr(o_string *o, int ch)
771 debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
772 if (b_check_space(o, 1)) return B_NOSPAC;
773 o->data[o->length] = ch;
775 o->data[o->length] = '\0';
779 static void b_reset(o_string *o)
783 if (o->data != NULL) *o->data = '\0';
786 static void b_free(o_string *o)
789 if (o->data != NULL) free(o->data);
794 /* My analysis of quoting semantics tells me that state information
795 * is associated with a destination, not a source.
797 static int b_addqchr(o_string *o, int ch, int quote)
799 if (quote && strchr("*?[\\",ch)) {
801 rc = b_addchr(o, '\\');
804 return b_addchr(o, ch);
807 /* belongs in utility.c */
808 char *simple_itoa(unsigned int i)
810 /* 21 digits plus null terminator, good for 64-bit or smaller ints */
811 static char local[22];
812 char *p = &local[21];
821 static int b_adduint(o_string *o, unsigned int i)
824 char *p = simple_itoa(i);
825 /* no escape checking necessary */
826 do r=b_addchr(o, *p++); while (r==0 && *p);
830 static int static_get(struct in_str *i)
833 if (ch=='\0') return EOF;
837 static int static_peek(struct in_str *i)
842 static inline void cmdedit_set_initial_prompt(void)
844 #ifndef BB_FEATURE_SH_FANCY_PROMPT
853 static inline void setup_prompt_string(int promptmode, char **prompt_str)
855 debug_printf("setup_prompt_string %d ",promptmode);
856 #ifndef BB_FEATURE_SH_FANCY_PROMPT
857 /* Set up the prompt */
858 if (promptmode == 1) {
861 PS1=xmalloc(strlen(cwd)+4);
862 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# ");
868 *prompt_str = (promptmode==0)? PS1 : PS2;
870 debug_printf("result %s\n",*prompt_str);
873 static void get_user_input(struct in_str *i)
876 static char the_command[BUFSIZ];
878 setup_prompt_string(i->promptmode, &prompt_str);
879 #ifdef BB_FEATURE_COMMAND_EDITING
881 ** enable command line editing only while a command line
882 ** is actually being read; otherwise, we'll end up bequeathing
883 ** atexit() handlers and other unwanted stuff to our
884 ** child processes (rob@sysgo.de)
886 cmdedit_read_input(prompt_str, the_command);
889 fputs(prompt_str, stdout);
891 the_command[0]=fgetc(i->file);
897 /* This is the magic location that prints prompts
898 * and gets data back from the user */
899 static int file_get(struct in_str *i)
904 /* If there is data waiting, eat it up */
908 /* need to double check i->file because we might be doing something
909 * more complicated by now, like sourcing or substituting. */
910 if (i->__promptme && interactive && i->file == stdin) {
921 debug_printf("b_getch: got a %d\n", ch);
923 if (ch == '\n') i->__promptme=1;
927 /* All the callers guarantee this routine will never be
928 * used right after a newline, so prompting is not needed.
930 static int file_peek(struct in_str *i)
935 static char buffer[2];
936 buffer[0] = fgetc(i->file);
939 debug_printf("b_peek: got a %d\n", *i->p);
944 static void setup_file_in_str(struct in_str *i, FILE *f)
954 static void setup_string_in_str(struct in_str *i, const char *s)
956 i->peek = static_peek;
963 static void mark_open(int fd)
965 struct close_me *new = xmalloc(sizeof(struct close_me));
967 new->next = close_me_head;
971 static void mark_closed(int fd)
973 struct close_me *tmp;
974 if (close_me_head == NULL || close_me_head->fd != fd)
975 error_msg_and_die("corrupt close_me");
977 close_me_head = close_me_head->next;
981 static void close_all()
984 for (c=close_me_head; c; c=c->next) {
987 close_me_head = NULL;
990 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
991 * and stderr if they are redirected. */
992 static int setup_redirects(struct child_prog *prog, int squirrel[])
995 struct redir_struct *redir;
997 for (redir=prog->redirects; redir; redir=redir->next) {
998 if (redir->dup == -1) {
999 mode=redir_table[redir->type].mode;
1000 openfd = open(redir->word.gl_pathv[0], mode, 0666);
1002 /* this could get lost if stderr has been redirected, but
1003 bash and ash both lose it as well (though zsh doesn't!) */
1004 perror_msg("error opening %s", redir->word.gl_pathv[0]);
1008 openfd = redir->dup;
1011 if (openfd != redir->fd) {
1012 if (squirrel && redir->fd < 3) {
1013 squirrel[redir->fd] = dup(redir->fd);
1018 dup2(openfd, redir->fd);
1026 static void restore_redirects(int squirrel[])
1029 for (i=0; i<3; i++) {
1032 /* No error checking. I sure wouldn't know what
1033 * to do with an error if I found one! */
1040 /* XXX this definitely needs some more thought, work, and
1041 * cribbing from other shells */
1042 static int pipe_wait(struct pipe *pi)
1044 int rcode=0, i, pid, running, status;
1045 running = pi->num_progs;
1047 pid=waitpid(-1, &status, 0);
1048 if (pid < 0) perror_msg_and_die("waitpid");
1049 for (i=0; i < pi->num_progs; i++) {
1050 if (pi->progs[i].pid == pid) {
1051 if (i==pi->num_progs-1) rcode=WEXITSTATUS(status);
1052 pi->progs[i].pid = 0;
1062 /* XXX no exit() here. If you don't exec, use _exit instead.
1063 * The at_exit handlers apparently confuse the calling process,
1064 * in particular stdin handling. Not sure why? */
1065 static void pseudo_exec(struct child_prog *child)
1068 struct built_in_command *x;
1070 for (i=0; is_assignment(child->argv[i]); i++) {
1071 debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
1072 putenv(strdup(child->argv[i]));
1074 child->argv+=i; /* XXX this hack isn't so horrible, since we are about
1075 to exit, and therefore don't need to keep data
1076 structures consistent for free() use. */
1077 /* If a variable is assigned in a forest, and nobody listens,
1078 * was it ever really set?
1080 if (child->argv[0] == NULL) {
1081 _exit(EXIT_SUCCESS);
1085 * Check if the command matches any of the builtins.
1086 * Depending on context, this might be redundant. But it's
1087 * easier to waste a few CPU cycles than it is to figure out
1088 * if this is one of those cases.
1090 for (x = bltins; x->cmd; x++) {
1091 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1092 debug_printf("builtin exec %s\n", child->argv[0]);
1093 _exit(x->function(child));
1097 /* Check if the command matches any busybox internal commands
1099 * FIXME: This feature is not 100% safe, since
1100 * BusyBox is not fully reentrant, so we have no guarantee the things
1101 * from the .bss are still zeroed, or that things from .data are still
1102 * at their defaults. We could exec ourself from /proc/self/exe, but I
1103 * really dislike relying on /proc for things. We could exec ourself
1104 * from global_argv[0], but if we are in a chroot, we may not be able
1105 * to find ourself... */
1106 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1109 char** argv_l=child->argv;
1110 char *name = child->argv[0];
1112 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1113 /* Following discussions from November 2000 on the busybox mailing
1114 * list, the default configuration, (without
1115 * get_last_path_component()) lets the user force use of an
1116 * external command by specifying the full (with slashes) filename.
1117 * If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then applets
1118 * _aways_ override external commands, so if you want to run
1119 * /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
1120 * filesystem and is _not_ busybox. Some systems may want this,
1122 name = get_last_path_component(name);
1124 /* Count argc for use in a second... */
1125 for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1127 debug_printf("running applet %s\n", name);
1128 run_applet_by_name(name, argc_l, child->argv);
1131 debug_printf("exec of %s\n",child->argv[0]);
1132 execvp(child->argv[0],child->argv);
1133 perror_msg("couldn't exec: %s",child->argv[0]);
1135 } else if (child->group) {
1136 debug_printf("runtime nesting to group\n");
1137 interactive=0; /* crucial!!!! */
1138 rcode = run_list_real(child->group);
1139 /* OK to leak memory by not calling run_list_test,
1140 * since this process is about to exit */
1143 /* Can happen. See what bash does with ">foo" by itself. */
1144 debug_printf("trying to pseudo_exec null command\n");
1145 _exit(EXIT_SUCCESS);
1149 static void insert_bg_job(struct pipe *pi)
1151 struct pipe *thejob;
1153 /* Linear search for the ID of the job to use */
1155 for (thejob = job_list->head; thejob; thejob = thejob->next)
1156 if (thejob->jobid >= pi->jobid)
1157 pi->jobid = thejob->jobid + 1;
1159 /* add thejob to the list of running jobs */
1160 if (!job_list->head) {
1161 thejob = job_list->head = xmalloc(sizeof(*thejob));
1163 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1164 thejob->next = xmalloc(sizeof(*thejob));
1165 thejob = thejob->next;
1168 /* physically copy the struct job */
1169 memcpy(thejob, pi, sizeof(struct pipe));
1170 thejob->next = NULL;
1171 thejob->running_progs = thejob->num_progs;
1172 thejob->stopped_progs = 0;
1173 thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
1175 //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1177 char *bar=thejob->text;
1178 char **foo=pi->progs[0].argv;
1179 while(foo && *foo) {
1180 bar += sprintf(bar, "%s ", *foo++);
1184 /* we don't wait for background thejobs to return -- append it
1185 to the list of backgrounded thejobs and leave it alone */
1186 printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1187 last_bg_pid = thejob->progs[0].pid;
1190 /* remove a backgrounded job from a jobset */
1191 static void remove_bg_job(struct pipe *pi)
1193 struct pipe *prev_pipe;
1195 if (pi == job_list->head) {
1196 job_list->head = pi->next;
1198 prev_pipe = job_list->head;
1199 while (prev_pipe->next != pi)
1200 prev_pipe = prev_pipe->next;
1201 prev_pipe->next = pi->next;
1208 /* free up all memory from a pipe */
1209 static void free_pipe(struct pipe *pi)
1213 for (i = 0; i < pi->num_progs; i++) {
1214 free(pi->progs[i].argv);
1215 if (pi->progs[i].redirects)
1216 free(pi->progs[i].redirects);
1224 memset(pi, 0, sizeof(struct pipe));
1228 /* Checks to see if any background processes have exited -- if they
1229 have, figure out why and see if a job has completed */
1230 static void checkjobs()
1237 while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
1238 for (pi = job_list->head; pi; pi = pi->next) {
1240 while (prognum < pi->num_progs &&
1241 pi->progs[prognum].pid != childpid) prognum++;
1242 if (prognum < pi->num_progs)
1249 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1251 pi->running_progs--;
1252 pi->progs[prognum].pid = 0;
1254 if (!pi->running_progs) {
1255 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1260 pi->stopped_progs++;
1261 pi->progs[prognum].is_stopped = 1;
1263 if (pi->stopped_progs == pi->num_progs) {
1264 printf(JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
1269 if (childpid == -1 && errno != ECHILD)
1270 perror_msg("waitpid");
1272 /* move the shell to the foreground */
1273 if (interactive && (ctty=controlling_tty(0))!=-1) {
1274 if (tcsetpgrp(ctty, getpgrp()))
1275 perror_msg("tcsetpgrp-2");
1279 /* Figure out our controlling tty, checking in order stderr,
1280 * stdin, and stdout. If check_pgrp is set, also check that
1281 * we belong to the foreground process group associated with
1282 * that tty. The value of ctty is needed in order to call
1283 * tcsetpgrp(ctty, ...); */
1284 int controlling_tty(int check_pgrp)
1289 if ((curpgrp = tcgetpgrp(ctty = 2)) < 0
1290 && (curpgrp = tcgetpgrp(ctty = 0)) < 0
1291 && (curpgrp = tcgetpgrp(ctty = 1)) < 0)
1292 return errno = ENOTTY, -1;
1294 if (check_pgrp && curpgrp != getpgrp())
1295 return errno = EPERM, -1;
1300 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1301 * to finish. See pipe_wait().
1303 * return code is normally -1, when the caller has to wait for children
1304 * to finish to determine the exit status of the pipe. If the pipe
1305 * is a simple builtin command, however, the action is done by the
1306 * time run_pipe_real returns, and the exit code is provided as the
1309 * The input of the pipe is always stdin, the output is always
1310 * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1311 * because it tries to avoid running the command substitution in
1312 * subshell, when that is in fact necessary. The subshell process
1313 * now has its stdout directed to the input of the appropriate pipe,
1314 * so this routine is noticeably simpler.
1316 static int run_pipe_real(struct pipe *pi)
1320 int nextin, nextout;
1321 int pipefds[2]; /* pipefds[0] is for reading */
1322 struct child_prog *child;
1323 struct built_in_command *x;
1329 /* Check if we are supposed to run in the foreground */
1330 if (interactive && pi->followup!=PIPE_BG) {
1331 if ((ctty = controlling_tty(pi->pgrp<0)) < 0) return -1;
1334 /* Check if this is a simple builtin (not part of a pipe).
1335 * Builtins within pipes have to fork anyway, and are handled in
1336 * pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
1338 if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1339 child = & (pi->progs[0]);
1340 if (child->group && ! child->subshell) {
1341 int squirrel[] = {-1, -1, -1};
1343 debug_printf("non-subshell grouping\n");
1344 setup_redirects(child, squirrel);
1345 /* XXX could we merge code with following builtin case,
1346 * by creating a pseudo builtin that calls run_list_real? */
1347 rcode = run_list_real(child->group);
1348 restore_redirects(squirrel);
1351 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1352 if (i!=0 && child->argv[i]==NULL) {
1353 /* assignments, but no command: set the local environment */
1354 for (i=0; child->argv[i]!=NULL; i++) {
1355 set_local_var(child->argv[i], 0);
1357 return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */
1359 for (x = bltins; x->cmd; x++) {
1360 if (strcmp(child->argv[i], x->cmd) == 0 ) {
1361 int squirrel[] = {-1, -1, -1};
1363 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1364 debug_printf("magic exec\n");
1365 setup_redirects(child,NULL);
1366 return EXIT_SUCCESS;
1368 debug_printf("builtin inline %s\n", child->argv[0]);
1369 /* XXX setup_redirects acts on file descriptors, not FILEs.
1370 * This is perfect for work that comes after exec().
1371 * Is it really safe for inline use? Experimentally,
1372 * things seem to work with glibc. */
1373 setup_redirects(child, squirrel);
1374 for (i=0; is_assignment(child->argv[i]); i++) {
1375 putenv(strdup(child->argv[i]));
1377 child->argv+=i; /* XXX horrible hack */
1378 rcode = x->function(child);
1379 child->argv-=i; /* XXX restore hack so free() can work right */
1380 restore_redirects(squirrel);
1386 for (i = 0; i < pi->num_progs; i++) {
1387 child = & (pi->progs[i]);
1389 /* pipes are inserted between pairs of commands */
1390 if ((i + 1) < pi->num_progs) {
1391 if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1392 nextout = pipefds[1];
1398 /* XXX test for failed fork()? */
1399 if (!(child->pid = fork())) {
1401 signal(SIGTTOU, SIG_DFL);
1413 if (pipefds[0]!=-1) {
1414 close(pipefds[0]); /* opposite end of our output pipe */
1417 /* Like bash, explicit redirects override pipes,
1418 * and the pipe fd is available for dup'ing. */
1419 setup_redirects(child,NULL);
1421 if (interactive && pi->followup!=PIPE_BG) {
1422 /* If we (the child) win the race, put ourselves in the process
1423 * group whose leader is the first process in this pipe. */
1425 pi->pgrp = getpid();
1427 if (setpgid(0, pi->pgrp) == 0) {
1428 signal(SIGTTOU, SIG_IGN);
1429 tcsetpgrp(ctty, pi->pgrp);
1430 signal(SIGTTOU, SIG_DFL);
1436 /* Put our child in the process group whose leader is the
1437 * first process in this pipe. */
1439 pi->pgrp = child->pid;
1441 /* Don't check for errors. The child may be dead already,
1442 * in which case setpgid returns error code EACCES. */
1443 setpgid(child->pid, pi->pgrp);
1450 /* If there isn't another process, nextin is garbage
1451 but it doesn't matter */
1452 nextin = pipefds[0];
1457 static int run_list_real(struct pipe *pi)
1460 int if_code=0, next_if_code=0; /* need double-buffer to handle elif */
1461 reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1462 for (;pi;pi=pi->next) {
1464 debug_printf("rmode=%d if_code=%d next_if_code=%d skip_more=%d\n", rmode, if_code, next_if_code, skip_more_in_this_rmode);
1465 if (rmode == skip_more_in_this_rmode) continue;
1466 skip_more_in_this_rmode = RES_XXXX;
1467 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1468 if (rmode == RES_THEN && if_code) continue;
1469 if (rmode == RES_ELSE && !if_code) continue;
1470 if (rmode == RES_ELIF && !if_code) continue;
1471 if (pi->num_progs == 0) continue;
1472 rcode = run_pipe_real(pi);
1474 /* We only ran a builtin: rcode was set by the return value
1475 * of run_pipe_real(), and we don't need to wait for anything. */
1476 } else if (pi->followup==PIPE_BG) {
1477 /* XXX check bash's behavior with nontrivial pipes */
1478 /* XXX compute jobid */
1479 /* XXX what does bash do with attempts to background builtins? */
1481 rcode = EXIT_SUCCESS;
1485 /* move the new process group into the foreground */
1486 /* suppress messages when run from /linuxrc mag@sysgo.de */
1487 /* XXX probably this "0" should come from controlling_tty() */
1488 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
1489 perror_msg("tcsetpgrp-3");
1490 rcode = pipe_wait(pi);
1491 if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
1492 perror_msg("tcsetpgrp-4");
1494 rcode = pipe_wait(pi);
1495 debug_printf("pipe_wait returned %d\n",rcode);
1498 last_return_code=rcode;
1499 if ( rmode == RES_IF || rmode == RES_ELIF )
1500 next_if_code=rcode; /* can be overwritten a number of times */
1501 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1502 (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1503 skip_more_in_this_rmode=rmode;
1509 /* broken, of course, but OK for testing */
1510 static char *indenter(int i)
1512 static char blanks[]=" ";
1513 return &blanks[sizeof(blanks)-i-1];
1516 /* return code is the exit status of the pipe */
1517 static int run_pipe_test(struct pipe *pi, int indent)
1520 struct child_prog *child;
1521 struct redir_struct *r, *rnext;
1522 int a, i, ret_code=0;
1523 char *ind = indenter(indent);
1524 final_printf("%s run pipe: (pid %d)\n",ind,getpid());
1525 for (i=0; i<pi->num_progs; i++) {
1526 child = &pi->progs[i];
1527 final_printf("%s command %d:\n",ind,i);
1529 for (a=0,p=child->argv; *p; a++,p++) {
1530 final_printf("%s argv[%d] = %s\n",ind,a,*p);
1532 globfree(&child->glob_result);
1534 } else if (child->group) {
1535 final_printf("%s begin group (subshell:%d)\n",ind, child->subshell);
1536 ret_code = run_list_test(child->group,indent+3);
1537 final_printf("%s end group\n",ind);
1539 final_printf("%s (nil)\n",ind);
1541 for (r=child->redirects; r; r=rnext) {
1542 final_printf("%s redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
1544 final_printf(" %s\n", *r->word.gl_pathv);
1547 final_printf("&%d\n", r->dup);
1552 child->redirects=NULL;
1554 free(pi->progs); /* children are an array, they get freed all at once */
1559 static int run_list_test(struct pipe *head, int indent)
1561 int rcode=0; /* if list has no members */
1562 struct pipe *pi, *next;
1563 char *ind = indenter(indent);
1564 for (pi=head; pi; pi=next) {
1565 if (pi->num_progs == 0) break;
1566 final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
1567 rcode = run_pipe_test(pi, indent);
1568 final_printf("%s pipe followup code %d\n", ind, pi->followup);
1576 /* Select which version we will use */
1577 static int run_list(struct pipe *pi)
1581 rcode = run_list_real(pi);
1583 /* run_list_test has the side effect of clearing memory
1584 * In the long run that function can be merged with run_list_real,
1585 * but doing that now would hobble the debugging effort. */
1586 run_list_test(pi,0);
1590 /* The API for glob is arguably broken. This routine pushes a non-matching
1591 * string into the output structure, removing non-backslashed backslashes.
1592 * If someone can prove me wrong, by performing this function within the
1593 * original glob(3) api, feel free to rewrite this routine into oblivion.
1594 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1595 * XXX broken if the last character is '\\', check that before calling.
1597 static int globhack(const char *src, int flags, glob_t *pglob)
1602 for (cnt=1, s=src; *s; s++) {
1603 if (*s == '\\') s++;
1607 if (!dest) return GLOB_NOSPACE;
1608 if (!(flags & GLOB_APPEND)) {
1609 pglob->gl_pathv=NULL;
1614 pathc = ++pglob->gl_pathc;
1615 pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1616 if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1617 pglob->gl_pathv[pathc-1]=dest;
1618 pglob->gl_pathv[pathc]=NULL;
1619 for (s=src; *s; s++, dest++) {
1620 if (*s == '\\') s++;
1627 /* XXX broken if the last character is '\\', check that before calling */
1628 static int glob_needed(const char *s)
1631 if (*s == '\\') s++;
1632 if (strchr("*[?",*s)) return 1;
1638 static void globprint(glob_t *pglob)
1641 debug_printf("glob_t at %p:\n", pglob);
1642 debug_printf(" gl_pathc=%d gl_pathv=%p gl_offs=%d gl_flags=%d\n",
1643 pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
1644 for (i=0; i<pglob->gl_pathc; i++)
1645 debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
1646 pglob->gl_pathv[i], pglob->gl_pathv[i]);
1650 static int xglob(o_string *dest, int flags, glob_t *pglob)
1654 /* short-circuit for null word */
1655 /* we can code this better when the debug_printf's are gone */
1656 if (dest->length == 0) {
1657 if (dest->nonnull) {
1658 /* bash man page calls this an "explicit" null */
1659 gr = globhack(dest->data, flags, pglob);
1660 debug_printf("globhack returned %d\n",gr);
1664 } else if (glob_needed(dest->data)) {
1665 gr = glob(dest->data, flags, NULL, pglob);
1666 debug_printf("glob returned %d\n",gr);
1667 if (gr == GLOB_NOMATCH) {
1668 /* quote removal, or more accurately, backslash removal */
1669 gr = globhack(dest->data, flags, pglob);
1670 debug_printf("globhack returned %d\n",gr);
1673 gr = globhack(dest->data, flags, pglob);
1674 debug_printf("globhack returned %d\n",gr);
1676 if (gr == GLOB_NOSPACE)
1677 error_msg_and_die("out of memory during glob");
1678 if (gr != 0) { /* GLOB_ABORTED ? */
1679 error_msg("glob(3) error %d",gr);
1681 /* globprint(glob_target); */
1685 /* This is used to get/check local shell variables */
1686 static char *get_local_var(const char *s)
1688 struct variables *cur;
1692 for (cur = top_vars; cur; cur=cur->next)
1693 if(strcmp(cur->name, s)==0)
1698 /* This is used to set local shell variables
1699 flg_export==0 if only local (not exporting) variable
1700 flg_export==1 if "new" exporting environ
1701 flg_export>1 if current startup environ (not call putenv()) */
1702 static int set_local_var(const char *s, int flg_export)
1706 struct variables *cur;
1711 /* Assume when we enter this function that we are already in
1712 * NAME=VALUE format. So the first order of business is to
1713 * split 's' on the '=' into 'name' and 'value' */
1714 value = strchr(name, '=');
1715 if (value==0 || (newval = strdup(value+1))==0) {
1720 for(cur = top_vars; cur; cur = cur->next) {
1721 if(strcmp(cur->name, name)==0)
1726 if(strcmp(cur->value, value)==0) {
1727 if(flg_export>0 && cur->flg_export==0)
1728 cur->flg_export=flg_export;
1733 if(cur->flg_read_only) {
1734 error_msg("%s: readonly variable", name);
1738 if(flg_export>0 || cur->flg_export>1)
1741 cur->value = newval;
1745 cur = malloc(sizeof(struct variables));
1750 cur->name = strdup(name);
1751 if(cur->name == 0) {
1756 struct variables *bottom = top_vars;
1757 cur->value = newval;
1759 cur->flg_export = flg_export;
1760 cur->flg_read_only = 0;
1761 while(bottom->next) bottom=bottom->next;
1768 if(result==0 && cur->flg_export==1) {
1770 result = putenv(name);
1773 if(result>0) /* equivalent to previous set */
1779 static void unset_local_var(const char *name)
1781 struct variables *cur;
1784 for (cur = top_vars; cur; cur=cur->next) {
1785 if(strcmp(cur->name, name)==0)
1789 struct variables *next = top_vars;
1790 if(cur->flg_read_only) {
1791 error_msg("%s: readonly variable", name);
1795 unsetenv(cur->name);
1798 while (next->next != cur)
1800 next->next = cur->next;
1807 static int is_assignment(const char *s)
1809 if (s==NULL || !isalpha(*s)) return 0;
1811 while(isalnum(*s) || *s=='_') ++s;
1815 /* the src parameter allows us to peek forward to a possible &n syntax
1816 * for file descriptor duplication, e.g., "2>&1".
1817 * Return code is 0 normally, 1 if a syntax error is detected in src.
1818 * Resource errors (in xmalloc) cause the process to exit */
1819 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1820 struct in_str *input)
1822 struct child_prog *child=ctx->child;
1823 struct redir_struct *redir = child->redirects;
1824 struct redir_struct *last_redir=NULL;
1826 /* Create a new redir_struct and drop it onto the end of the linked list */
1831 redir = xmalloc(sizeof(struct redir_struct));
1834 last_redir->next=redir;
1836 child->redirects=redir;
1840 redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1842 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1844 /* Check for a '2>&1' type redirect */
1845 redir->dup = redirect_dup_num(input);
1846 if (redir->dup == -2) return 1; /* syntax error */
1847 if (redir->dup != -1) {
1848 /* Erik had a check here that the file descriptor in question
1849 * is legit; I postpone that to "run time"
1850 * A "-" representation of "close me" shows up as a -3 here */
1851 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1853 /* We do _not_ try to open the file that src points to,
1854 * since we need to return and let src be expanded first.
1855 * Set ctx->pending_redirect, so we know what to do at the
1856 * end of the next parsed word.
1858 ctx->pending_redirect = redir;
1863 struct pipe *new_pipe(void) {
1865 pi = xmalloc(sizeof(struct pipe));
1869 pi->followup = 0; /* invalid */
1873 static void initialize_context(struct p_context *ctx)
1876 ctx->pending_redirect=NULL;
1878 ctx->list_head=new_pipe();
1879 ctx->pipe=ctx->list_head;
1882 done_command(ctx); /* creates the memory for working child */
1885 /* normal return is 0
1886 * if a reserved word is found, and processed, return 1
1887 * should handle if, then, elif, else, fi, for, while, until, do, done.
1888 * case, function, and select are obnoxious, save those for later.
1890 int reserved_word(o_string *dest, struct p_context *ctx)
1892 struct reserved_combo {
1897 /* Mostly a list of accepted follow-up reserved words.
1898 * FLAG_END means we are done with the sequence, and are ready
1899 * to turn the compound list into a command.
1900 * FLAG_START means the word must start a new compound list.
1902 static struct reserved_combo reserved_list[] = {
1903 { "if", RES_IF, FLAG_THEN | FLAG_START },
1904 { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
1905 { "elif", RES_ELIF, FLAG_THEN },
1906 { "else", RES_ELSE, FLAG_FI },
1907 { "fi", RES_FI, FLAG_END },
1908 { "for", RES_FOR, FLAG_DO | FLAG_START },
1909 { "while", RES_WHILE, FLAG_DO | FLAG_START },
1910 { "until", RES_UNTIL, FLAG_DO | FLAG_START },
1911 { "do", RES_DO, FLAG_DONE },
1912 { "done", RES_DONE, FLAG_END }
1914 struct reserved_combo *r;
1915 for (r=reserved_list;
1916 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
1917 r<reserved_list+NRES; r++) {
1918 if (strcmp(dest->data, r->literal) == 0) {
1919 debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
1920 if (r->flag & FLAG_START) {
1921 struct p_context *new = xmalloc(sizeof(struct p_context));
1922 debug_printf("push stack\n");
1923 *new = *ctx; /* physical copy */
1924 initialize_context(ctx);
1926 } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
1933 ctx->old_flag = r->flag;
1934 if (ctx->old_flag & FLAG_END) {
1935 struct p_context *old;
1936 debug_printf("pop stack\n");
1938 old->child->group = ctx->list_head;
1939 *ctx = *old; /* physical copy */
1949 /* normal return is 0.
1950 * Syntax or xglob errors return 1. */
1951 static int done_word(o_string *dest, struct p_context *ctx)
1953 struct child_prog *child=ctx->child;
1954 glob_t *glob_target;
1957 debug_printf("done_word: %s %p\n", dest->data, child);
1958 if (dest->length == 0 && !dest->nonnull) {
1959 debug_printf(" true null, ignored\n");
1962 if (ctx->pending_redirect) {
1963 glob_target = &ctx->pending_redirect->word;
1967 return 1; /* syntax error, groups and arglists don't mix */
1970 debug_printf("checking %s for reserved-ness\n",dest->data);
1971 if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
1973 glob_target = &child->glob_result;
1974 if (child->argv) flags |= GLOB_APPEND;
1976 gr = xglob(dest, flags, glob_target);
1977 if (gr != 0) return 1;
1980 if (ctx->pending_redirect) {
1981 ctx->pending_redirect=NULL;
1982 if (glob_target->gl_pathc != 1) {
1983 error_msg("ambiguous redirect");
1987 child->argv = glob_target->gl_pathv;
1992 /* The only possible error here is out of memory, in which case
1994 static int done_command(struct p_context *ctx)
1996 /* The child is really already in the pipe structure, so
1997 * advance the pipe counter and make a new, null child.
1998 * Only real trickiness here is that the uncommitted
1999 * child structure, to which ctx->child points, is not
2000 * counted in pi->num_progs. */
2001 struct pipe *pi=ctx->pipe;
2002 struct child_prog *prog=ctx->child;
2004 if (prog && prog->group == NULL
2005 && prog->argv == NULL
2006 && prog->redirects == NULL) {
2007 debug_printf("done_command: skipping null command\n");
2011 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
2013 debug_printf("done_command: initializing\n");
2015 pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2017 prog = pi->progs + pi->num_progs;
2018 prog->redirects = NULL;
2020 prog->is_stopped = 0;
2022 prog->glob_result.gl_pathv = NULL;
2026 /* but ctx->pipe and ctx->list_head remain unchanged */
2030 static int done_pipe(struct p_context *ctx, pipe_style type)
2033 done_command(ctx); /* implicit closure of previous command */
2034 debug_printf("done_pipe, type %d\n", type);
2035 ctx->pipe->followup = type;
2036 ctx->pipe->r_mode = ctx->w;
2038 ctx->pipe->next = new_p;
2041 done_command(ctx); /* set up new pipe to accept commands */
2045 /* peek ahead in the in_str to find out if we have a "&n" construct,
2046 * as in "2>&1", that represents duplicating a file descriptor.
2047 * returns either -2 (syntax error), -1 (no &), or the number found.
2049 static int redirect_dup_num(struct in_str *input)
2053 if (ch != '&') return -1;
2055 b_getch(input); /* get the & */
2059 return -3; /* "-" represents "close me" */
2061 while (isdigit(ch)) {
2069 error_msg("ambiguous redirect");
2073 /* If a redirect is immediately preceded by a number, that number is
2074 * supposed to tell which file descriptor to redirect. This routine
2075 * looks for such preceding numbers. In an ideal world this routine
2076 * needs to handle all the following classes of redirects...
2077 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
2078 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
2079 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
2080 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
2081 * A -1 output from this program means no valid number was found, so the
2082 * caller should use the appropriate default for this redirection.
2084 static int redirect_opt_num(o_string *o)
2088 if (o->length==0) return -1;
2089 for(num=0; num<o->length; num++) {
2090 if (!isdigit(*(o->data+num))) {
2094 /* reuse num (and save an int) */
2100 FILE *generate_stream_from_list(struct pipe *head)
2104 int pid, channel[2];
2105 if (pipe(channel)<0) perror_msg_and_die("pipe");
2108 perror_msg_and_die("fork");
2109 } else if (pid==0) {
2111 if (channel[1] != 1) {
2116 #define SURROGATE "surrogate response"
2117 write(1,SURROGATE,sizeof(SURROGATE));
2118 _exit(run_list(head));
2120 _exit(run_list_real(head)); /* leaks memory */
2123 debug_printf("forked child %d\n",pid);
2125 pf = fdopen(channel[0],"r");
2126 debug_printf("pipe on FILE *%p\n",pf);
2128 run_list_test(head,0);
2129 pf=popen("echo surrogate response","r");
2130 debug_printf("started fake pipe on FILE *%p\n",pf);
2135 /* this version hacked for testing purposes */
2136 /* return code is exit status of the process that is run. */
2137 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2140 o_string result=NULL_O_STRING;
2141 struct p_context inner;
2143 struct in_str pipe_str;
2144 initialize_context(&inner);
2146 /* recursion to generate command */
2147 retcode = parse_stream(&result, &inner, input, subst_end);
2148 if (retcode != 0) return retcode; /* syntax error or EOF */
2149 done_word(&result, &inner);
2150 done_pipe(&inner, PIPE_SEQ);
2153 p=generate_stream_from_list(inner.list_head);
2154 if (p==NULL) return 1;
2155 mark_open(fileno(p));
2156 setup_file_in_str(&pipe_str, p);
2158 /* now send results of command back into original context */
2159 retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2160 /* XXX In case of a syntax error, should we try to kill the child?
2161 * That would be tough to do right, so just read until EOF. */
2163 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2166 debug_printf("done reading from pipe, pclose()ing\n");
2167 /* This is the step that wait()s for the child. Should be pretty
2168 * safe, since we just read an EOF from its stdout. We could try
2169 * to better, by using wait(), and keeping track of background jobs
2170 * at the same time. That would be a lot of work, and contrary
2171 * to the KISS philosophy of this program. */
2172 mark_closed(fileno(p));
2174 debug_printf("pclosed, retcode=%d\n",retcode);
2175 /* XXX this process fails to trim a single trailing newline */
2179 static int parse_group(o_string *dest, struct p_context *ctx,
2180 struct in_str *input, int ch)
2183 struct p_context sub;
2184 struct child_prog *child = ctx->child;
2187 return 1; /* syntax error, groups and arglists don't mix */
2189 initialize_context(&sub);
2191 case '(': endch=')'; child->subshell=1; break;
2192 case '{': endch='}'; break;
2193 default: syntax(); /* really logic error */
2195 rcode=parse_stream(dest,&sub,input,endch);
2196 done_word(dest,&sub); /* finish off the final word in the subcontext */
2197 done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
2198 child->group = sub.list_head;
2200 /* child remains "open", available for possible redirects */
2203 /* basically useful version until someone wants to get fancier,
2204 * see the bash man page under "Parameter Expansion" */
2205 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src)
2209 p = getenv(src->data);
2211 p = get_local_var(src->data);
2213 if (p) parse_string(dest, ctx, p); /* recursion */
2217 /* return code: 0 for OK, 1 for syntax error */
2218 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2221 o_string alt=NULL_O_STRING;
2223 int ch = input->peek(input); /* first character after the $ */
2224 debug_printf("handle_dollar: ch=%c\n",ch);
2226 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2230 lookup_param(dest, ctx, &alt);
2231 } else if (isdigit(ch)) {
2232 i = ch-'0'; /* XXX is $0 special? */
2233 if (i<global_argc) {
2234 parse_string(dest, ctx, global_argv[i]); /* recursion */
2237 } else switch (ch) {
2239 b_adduint(dest,getpid());
2243 if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2247 b_adduint(dest,last_return_code);
2251 b_adduint(dest,global_argc ? global_argc-1 : 0);
2256 /* XXX maybe someone will try to escape the '}' */
2257 while(ch=b_getch(input),ch!=EOF && ch!='}') {
2264 lookup_param(dest, ctx, &alt);
2268 process_command_subs(dest, ctx, input, ')');
2272 for (i=1; i<global_argc; i++) {
2273 parse_string(dest, ctx, global_argv[i]);
2274 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2280 /* still unhandled, but should be eventually */
2281 error_msg("unhandled syntax: $%c",ch);
2285 b_addqchr(dest,'$',dest->quote);
2287 /* Eat the character if the flag was set. If the compiler
2288 * is smart enough, we could substitute "b_getch(input);"
2289 * for all the "advance = 1;" above, and also end up with
2290 * a nice size-optimized program. Hah! That'll be the day.
2292 if (advance) b_getch(input);
2296 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2299 setup_string_in_str(&foo, src);
2300 return parse_stream(dest, ctx, &foo, '\0');
2303 /* return code is 0 for normal exit, 1 for syntax error */
2304 int parse_stream(o_string *dest, struct p_context *ctx,
2305 struct in_str *input, int end_trigger)
2309 redir_type redir_style;
2312 /* Only double-quote state is handled in the state variable dest->quote.
2313 * A single-quote triggers a bypass of the main loop until its mate is
2314 * found. When recursing, quote state is passed in via dest->quote. */
2316 debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2317 while ((ch=b_getch(input))!=EOF) {
2319 next = (ch == '\n') ? 0 : b_peek(input);
2320 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2321 ch,ch,m,dest->quote);
2322 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2323 b_addqchr(dest, ch, dest->quote);
2325 if (m==2) { /* unquoted IFS */
2326 done_word(dest, ctx);
2327 /* If we aren't performing a substitution, treat a newline as a
2328 * command separator. */
2329 if (end_trigger != '\0' && ch=='\n')
2330 done_pipe(ctx,PIPE_SEQ);
2332 if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2333 debug_printf("leaving parse_stream\n");
2338 /* Yahoo! Time to run with it! */
2339 done_pipe(ctx,PIPE_SEQ);
2340 run_list(ctx->list_head);
2341 initialize_context(ctx);
2344 if (m!=2) switch (ch) {
2346 if (dest->length == 0 && !dest->quote) {
2347 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2349 b_addqchr(dest, ch, dest->quote);
2357 b_addqchr(dest, '\\', dest->quote);
2358 b_addqchr(dest, b_getch(input), dest->quote);
2361 if (handle_dollar(dest, ctx, input)!=0) return 1;
2365 while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2375 dest->quote = !dest->quote;
2378 process_command_subs(dest, ctx, input, '`');
2381 redir_fd = redirect_opt_num(dest);
2382 done_word(dest, ctx);
2383 redir_style=REDIRECT_OVERWRITE;
2385 redir_style=REDIRECT_APPEND;
2387 } else if (next == '(') {
2388 syntax(); /* until we support >(list) Process Substitution */
2391 setup_redirect(ctx, redir_fd, redir_style, input);
2394 redir_fd = redirect_opt_num(dest);
2395 done_word(dest, ctx);
2396 redir_style=REDIRECT_INPUT;
2398 redir_style=REDIRECT_HEREIS;
2400 } else if (next == '>') {
2401 redir_style=REDIRECT_IO;
2403 } else if (next == '(') {
2404 syntax(); /* until we support <(list) Process Substitution */
2407 setup_redirect(ctx, redir_fd, redir_style, input);
2410 done_word(dest, ctx);
2411 done_pipe(ctx,PIPE_SEQ);
2414 done_word(dest, ctx);
2417 done_pipe(ctx,PIPE_AND);
2419 done_pipe(ctx,PIPE_BG);
2423 done_word(dest, ctx);
2426 done_pipe(ctx,PIPE_OR);
2428 /* we could pick up a file descriptor choice here
2429 * with redirect_opt_num(), but bash doesn't do it.
2430 * "echo foo 2| cat" yields "foo 2". */
2436 if (parse_group(dest, ctx, input, ch)!=0) return 1;
2440 syntax(); /* Proper use of this character caught by end_trigger */
2444 syntax(); /* this is really an internal logic error */
2449 /* complain if quote? No, maybe we just finished a command substitution
2450 * that was quoted. Example:
2451 * $ echo "`cat foo` plus more"
2452 * and we just got the EOF generated by the subshell that ran "cat foo"
2453 * The only real complaint is if we got an EOF when end_trigger != '\0',
2454 * that is, we were really supposed to get end_trigger, and never got
2455 * one before the EOF. Can't use the standard "syntax error" return code,
2456 * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2457 if (end_trigger != '\0') return -1;
2461 void mapset(const unsigned char *set, int code)
2463 const unsigned char *s;
2464 for (s=set; *s; s++) map[*s] = code;
2467 void update_ifs_map(void)
2469 /* char *ifs and char map[256] are both globals. */
2470 ifs = getenv("IFS");
2471 if (ifs == NULL) ifs=" \t\n";
2472 /* Precompute a list of 'flow through' behavior so it can be treated
2473 * quickly up front. Computation is necessary because of IFS.
2474 * Special case handling of IFS == " \t\n" is not implemented.
2475 * The map[] array only really needs two bits each, and on most machines
2476 * that would be faster because of the reduced L1 cache footprint.
2478 memset(map,0,sizeof(map)); /* most characters flow through always */
2479 mapset("\\$'\"`", 3); /* never flow through */
2480 mapset("<>;&|(){}#", 1); /* flow through if quoted */
2481 mapset(ifs, 2); /* also flow through if quoted */
2484 /* most recursion does not come through here, the exeception is
2485 * from builtin_source() */
2486 int parse_stream_outer(struct in_str *inp)
2489 struct p_context ctx;
2490 o_string temp=NULL_O_STRING;
2493 initialize_context(&ctx);
2496 rcode = parse_stream(&temp, &ctx, inp, '\n');
2497 done_word(&temp, &ctx);
2498 done_pipe(&ctx,PIPE_SEQ);
2499 run_list(ctx.list_head);
2500 } while (rcode != -1); /* loop on syntax errors, return on EOF */
2504 static int parse_string_outer(const char *s)
2506 struct in_str input;
2507 setup_string_in_str(&input, s);
2508 return parse_stream_outer(&input);
2511 static int parse_file_outer(FILE *f)
2514 struct in_str input;
2515 setup_file_in_str(&input, f);
2516 rcode = parse_stream_outer(&input);
2521 /* I think Erik wrote this. It looks imperfect at best */
2522 void grab_tty_control(void)
2526 initialpgrp = tcgetpgrp(fileno(stderr));
2527 if (initialpgrp < 0) {
2528 error_msg("sh: can't access tty; job control disabled\n");
2530 if (initialpgrp == -1)
2531 initialpgrp = getpgrp();
2532 else if (initialpgrp != getpgrp()) {
2533 killpg(initialpgrp, SIGTTIN);
2539 int shell_main(int argc, char **argv)
2543 struct jobset joblist_end = { NULL, NULL };
2546 /* XXX what should these be while sourcing /etc/profile? */
2550 /* (re?) initialize globals. Sometimes shell_main() ends up calling
2551 * shell_main(), therefore we cannot rely on the BSS to zero out this
2552 * stuff. Reset these to 0 every time. */
2554 /* map[] is taken care of with call to update_ifs_map() */
2557 close_me_head = NULL;
2560 /* Initialize some more globals to non-zero values */
2562 job_list = &joblist_end;
2563 #ifdef BB_FEATURE_COMMAND_EDITING
2564 cmdedit_set_initial_prompt();
2570 /* initialize our shell local variables with the values
2571 * currently living in the environment */
2574 set_local_var(*e, 2); /* without call putenv() */
2577 last_return_code=EXIT_SUCCESS;
2580 /* If we get started under a job aware app (like bash
2581 * for example), make sure we are now in charge so we
2582 * don't fight over who gets the foreground */
2583 /* don't pay any attention to this signal; it just confuses
2584 things and isn't really meant for shells anyway */
2585 signal(SIGTTOU, SIG_IGN);
2586 setpgid(0, getpid());
2587 tcsetpgrp(fileno(stderr), getpid());
2589 if (argv[0] && argv[0][0] == '-') {
2590 debug_printf("\nsourcing /etc/profile\n");
2591 input = xfopen("/etc/profile", "r");
2592 mark_open(fileno(input));
2593 parse_file_outer(input);
2594 mark_closed(fileno(input));
2599 while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2603 global_argv = argv+optind;
2604 global_argc = argc-optind;
2605 opt = parse_string_outer(optarg);
2617 fprintf(stderr, "Usage: sh [FILE]...\n"
2618 " or: sh -c command [args]...\n\n");
2625 /* A shell is interactive if the `-i' flag was given, or if all of
2626 * the following conditions are met:
2628 * no arguments remaining or the -s flag given
2629 * standard input is a terminal
2630 * standard output is a terminal
2631 * Refer to Posix.2, the description of the `sh' utility. */
2632 if (argv[optind]==NULL && input==stdin &&
2633 isatty(fileno(stdin)) && isatty(fileno(stdout))) {
2637 debug_printf("\ninteractive=%d\n", interactive);
2639 /* Looks like they want an interactive shell */
2640 fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n");
2643 if (argv[optind]==NULL) {
2644 opt=parse_file_outer(stdin);
2648 debug_printf("\nrunning script '%s'\n", argv[optind]);
2649 global_argv = argv+optind;
2650 global_argc = argc-optind;
2651 input = xfopen(argv[optind], "r");
2652 opt = parse_file_outer(input);
2654 #ifdef BB_FEATURE_CLEAN_UP
2656 if (cwd && cwd != unknown)
2659 struct variables *cur, *tmp;
2660 for(cur = top_vars; cur; cur = tmp) {
2662 if (!cur->flg_read_only) {
2672 return(opt?opt:last_return_code);