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;
259 static char PS2[] = "> ";
261 struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
263 struct variables *top_vars = &shell_ver;
265 #define B_CHUNK (100)
275 #define NULL_O_STRING {NULL,0,0,0,0}
276 /* used for initialization:
277 o_string foo = NULL_O_STRING; */
279 /* I can almost use ordinary FILE *. Is open_memstream() universally
280 * available? Where is it documented? */
286 int (*get) (struct in_str *);
287 int (*peek) (struct in_str *);
289 #define b_getch(input) ((input)->get(input))
290 #define b_peek(input) ((input)->peek(input))
292 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
294 struct built_in_command {
295 char *cmd; /* name */
296 char *descr; /* description */
297 int (*function) (struct child_prog *); /* function ptr */
300 /* belongs in busybox.h */
301 static inline int max(int a, int b) {
305 /* This should be in utility.c */
307 static void debug_printf(const char *format, ...)
310 va_start(args, format);
311 vfprintf(stderr, format, args);
315 static inline void debug_printf(const char *format, ...) { }
317 #define final_printf debug_printf
319 static void __syntax(char *file, int line) {
320 error_msg("syntax error %s:%d", file, line);
322 #define syntax() __syntax(__FILE__, __LINE__)
324 /* Index of subroutines: */
325 /* function prototypes for builtins */
326 static int builtin_cd(struct child_prog *child);
327 static int builtin_env(struct child_prog *child);
328 static int builtin_exec(struct child_prog *child);
329 static int builtin_exit(struct child_prog *child);
330 static int builtin_export(struct child_prog *child);
331 static int builtin_fg_bg(struct child_prog *child);
332 static int builtin_help(struct child_prog *child);
333 static int builtin_jobs(struct child_prog *child);
334 static int builtin_pwd(struct child_prog *child);
335 static int builtin_read(struct child_prog *child);
336 static int builtin_set(struct child_prog *child);
337 static int builtin_shift(struct child_prog *child);
338 static int builtin_source(struct child_prog *child);
339 static int builtin_umask(struct child_prog *child);
340 static int builtin_unset(struct child_prog *child);
341 static int builtin_not_written(struct child_prog *child);
342 /* o_string manipulation: */
343 static int b_check_space(o_string *o, int len);
344 static int b_addchr(o_string *o, int ch);
345 static void b_reset(o_string *o);
346 static int b_addqchr(o_string *o, int ch, int quote);
347 static int b_adduint(o_string *o, unsigned int i);
348 /* in_str manipulations: */
349 static int static_get(struct in_str *i);
350 static int static_peek(struct in_str *i);
351 static int file_get(struct in_str *i);
352 static int file_peek(struct in_str *i);
353 static void setup_file_in_str(struct in_str *i, FILE *f);
354 static void setup_string_in_str(struct in_str *i, const char *s);
355 /* close_me manipulations: */
356 static void mark_open(int fd);
357 static void mark_closed(int fd);
358 static void close_all();
359 /* "run" the final data structures: */
360 static char *indenter(int i);
361 static int run_list_test(struct pipe *head, int indent);
362 static int run_pipe_test(struct pipe *pi, int indent);
363 /* really run the final data structures: */
364 static int setup_redirects(struct child_prog *prog, int squirrel[]);
365 static int pipe_wait(struct pipe *pi);
366 static int run_list_real(struct pipe *pi);
367 static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
368 int controlling_tty(int check_pgrp);
369 static int run_pipe_real(struct pipe *pi);
370 /* extended glob support: */
371 static int globhack(const char *src, int flags, glob_t *pglob);
372 static int glob_needed(const char *s);
373 static int xglob(o_string *dest, int flags, glob_t *pglob);
374 /* variable assignment: */
375 static int is_assignment(const char *s);
376 /* data structure manipulation: */
377 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
378 static void initialize_context(struct p_context *ctx);
379 static int done_word(o_string *dest, struct p_context *ctx);
380 static int done_command(struct p_context *ctx);
381 static int done_pipe(struct p_context *ctx, pipe_style type);
382 /* primary string parsing: */
383 static int redirect_dup_num(struct in_str *input);
384 static int redirect_opt_num(o_string *o);
385 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
386 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
387 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src);
388 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
389 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
390 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
392 static int parse_stream_outer(struct in_str *inp);
393 static int parse_string_outer(const char *s);
394 static int parse_file_outer(FILE *f);
395 /* job management: */
396 static void checkjobs();
397 static void insert_bg_job(struct pipe *pi);
398 static void remove_bg_job(struct pipe *pi);
399 static void free_pipe(struct pipe *pi);
400 /* local variable support */
401 static char *get_local_var(const char *var);
402 static void unset_local_var(const char *name);
403 static int set_local_var(const char *s, int flg_export);
406 /* Table of built-in functions. They can be forked or not, depending on
407 * context: within pipes, they fork. As simple commands, they do not.
408 * When used in non-forking context, they can change global variables
409 * in the parent shell process. If forked, of course they can not.
410 * For example, 'unset foo | whatever' will parse and run, but foo will
411 * still be set at the end. */
412 static struct built_in_command bltins[] = {
413 {"bg", "Resume a job in the background", builtin_fg_bg},
414 {"break", "Exit for, while or until loop", builtin_not_written},
415 {"cd", "Change working directory", builtin_cd},
416 {"continue", "Continue for, while or until loop", builtin_not_written},
417 {"env", "Print all environment variables", builtin_env},
418 {"eval", "Construct and run shell command", builtin_not_written},
419 {"exec", "Exec command, replacing this shell with the exec'd process",
421 {"exit", "Exit from shell()", builtin_exit},
422 {"export", "Set environment variable", builtin_export},
423 {"fg", "Bring job into the foreground", builtin_fg_bg},
424 {"jobs", "Lists the active jobs", builtin_jobs},
425 {"pwd", "Print current directory", builtin_pwd},
426 {"read", "Input environment variable", builtin_read},
427 {"return", "Return from a function", builtin_not_written},
428 {"set", "Set/unset shell local variables", builtin_set},
429 {"shift", "Shift positional parameters", builtin_shift},
430 {"trap", "Trap signals", builtin_not_written},
431 {"ulimit","Controls resource limits", builtin_not_written},
432 {"umask","Sets file creation mask", builtin_umask},
433 {"unset", "Unset environment variable", builtin_unset},
434 {".", "Source-in and run commands in a file", builtin_source},
435 {"help", "List shell built-in commands", builtin_help},
439 static const char *set_cwd(void)
442 cwd = NULL; /* xgetcwd(arg) called free(arg) */
443 cwd = xgetcwd((char *)cwd);
450 /* built-in 'cd <path>' handler */
451 static int builtin_cd(struct child_prog *child)
454 if (child->argv[1] == NULL)
455 newdir = getenv("HOME");
457 newdir = child->argv[1];
459 printf("cd: %s: %s\n", newdir, strerror(errno));
466 /* built-in 'env' handler */
467 static int builtin_env(struct child_prog *dummy)
470 if (e == NULL) return EXIT_FAILURE;
477 /* built-in 'exec' handler */
478 static int builtin_exec(struct child_prog *child)
480 if (child->argv[1] == NULL)
481 return EXIT_SUCCESS; /* Really? */
487 /* built-in 'exit' handler */
488 static int builtin_exit(struct child_prog *child)
490 if (child->argv[1] == NULL)
491 exit(last_return_code);
492 exit (atoi(child->argv[1]));
495 /* built-in 'export VAR=value' handler */
496 static int builtin_export(struct child_prog *child)
499 char *name = child->argv[1];
502 return (builtin_env(child));
508 char *value = strchr(name, '=');
512 /* They are exporting something without an =VALUE */
514 value = get_local_var(name);
516 size_t ln = strlen(name);
518 tmp = realloc(name, ln+strlen(value)+2);
522 sprintf(tmp+ln, "=%s", value);
526 /* bash not put error and set error code
527 if exporting not defined variable */
533 perror_msg("export");
535 res = set_local_var(name, 1);
542 /* built-in 'fg' and 'bg' handler */
543 static int builtin_fg_bg(struct child_prog *child)
546 struct pipe *pi=NULL;
548 /* If they gave us no args, assume they want the last backgrounded task */
549 if (!child->argv[1]) {
550 for (pi = job_list->head; pi; pi = pi->next) {
551 if (pi->progs && pi->progs->pid == last_bg_pid) {
556 error_msg("%s: no current job", child->argv[0]);
560 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
561 error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
565 for (pi = job_list->head; pi; pi = pi->next) {
566 if (pi->jobid == jobnum) {
571 error_msg("%s: %d: no such job", child->argv[0], jobnum);
575 if (*child->argv[0] == 'f') {
576 /* Make this job the foreground job */
577 signal(SIGTTOU, SIG_IGN);
578 /* suppress messages when run from /linuxrc mag@sysgo.de */
579 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
580 perror_msg("tcsetpgrp-1");
581 signal(SIGTTOU, SIG_DFL);
585 /* Restart the processes in the job */
586 for (i = 0; i < pi->num_progs; i++)
587 pi->progs[i].is_stopped = 0;
589 kill(-pi->pgrp, SIGCONT);
591 pi->stopped_progs = 0;
595 /* built-in 'help' handler */
596 static int builtin_help(struct child_prog *dummy)
598 struct built_in_command *x;
600 printf("\nBuilt-in commands:\n");
601 printf("-------------------\n");
602 for (x = bltins; x->cmd; x++) {
605 printf("%s\t%s\n", x->cmd, x->descr);
611 /* built-in 'jobs' handler */
612 static int builtin_jobs(struct child_prog *child)
617 for (job = job_list->head; job; job = job->next) {
618 if (job->running_progs == job->stopped_progs)
619 status_string = "Stopped";
621 status_string = "Running";
622 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
628 /* built-in 'pwd' handler */
629 static int builtin_pwd(struct child_prog *dummy)
635 /* built-in 'read VAR' handler */
636 static int builtin_read(struct child_prog *child)
640 if (child->argv[1]) {
644 string[0] = 0; /* for correct work if stdin have "only EOF" */
646 fgets(string, sizeof(string), stdin);
648 var = malloc(strlen(child->argv[1])+strlen(string)+2);
650 sprintf(var, "%s=%s", child->argv[1], string);
651 res = set_local_var(var, 0);
655 fprintf(stderr, "read: %m\n");
656 free(var); /* not move up - saved errno */
659 do res=getchar(); while(res!='\n' && res!=EOF);
664 /* built-in 'set VAR=value' handler */
665 static int builtin_set(struct child_prog *child)
667 char *temp = child->argv[1];
671 for(e = top_vars; e; e=e->next)
672 printf("%s=%s\n", e->name, e->value);
674 set_local_var(temp, 0);
680 /* Built-in 'shift' handler */
681 static int builtin_shift(struct child_prog *child)
684 if (child->argv[1]) {
685 n=atoi(child->argv[1]);
687 if (n>=0 && n<global_argc) {
688 /* XXX This probably breaks $0 */
697 /* Built-in '.' handler (read-in and execute commands from file) */
698 static int builtin_source(struct child_prog *child)
703 if (child->argv[1] == NULL)
706 /* XXX search through $PATH is missing */
707 input = fopen(child->argv[1], "r");
709 error_msg("Couldn't open file '%s'", child->argv[1]);
713 /* Now run the file */
714 /* XXX argv and argc are broken; need to save old global_argv
715 * (pointer only is OK!) on this stack frame,
716 * set global_argv=child->argv+1, recurse, and restore. */
717 mark_open(fileno(input));
718 status = parse_file_outer(input);
719 mark_closed(fileno(input));
724 static int builtin_umask(struct child_prog *child)
727 const char *arg = child->argv[1];
730 new_umask=strtoul(arg, &end, 8);
731 if (*end!='\0' || end == arg) {
735 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
741 /* built-in 'unset VAR' handler */
742 static int builtin_unset(struct child_prog *child)
744 /* bash returned already true */
745 unset_local_var(child->argv[1]);
749 static int builtin_not_written(struct child_prog *child)
751 printf("builtin_%s not written\n",child->argv[0]);
755 static int b_check_space(o_string *o, int len)
757 /* It would be easy to drop a more restrictive policy
758 * in here, such as setting a maximum string length */
759 if (o->length + len > o->maxlen) {
760 char *old_data = o->data;
761 /* assert (data == NULL || o->maxlen != 0); */
762 o->maxlen += max(2*len, B_CHUNK);
763 o->data = realloc(o->data, 1 + o->maxlen);
764 if (o->data == NULL) {
768 return o->data == NULL;
771 static int b_addchr(o_string *o, int ch)
773 debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
774 if (b_check_space(o, 1)) return B_NOSPAC;
775 o->data[o->length] = ch;
777 o->data[o->length] = '\0';
781 static void b_reset(o_string *o)
785 if (o->data != NULL) *o->data = '\0';
788 static void b_free(o_string *o)
791 if (o->data != NULL) free(o->data);
796 /* My analysis of quoting semantics tells me that state information
797 * is associated with a destination, not a source.
799 static int b_addqchr(o_string *o, int ch, int quote)
801 if (quote && strchr("*?[\\",ch)) {
803 rc = b_addchr(o, '\\');
806 return b_addchr(o, ch);
809 /* belongs in utility.c */
810 char *simple_itoa(unsigned int i)
812 /* 21 digits plus null terminator, good for 64-bit or smaller ints */
813 static char local[22];
814 char *p = &local[21];
823 static int b_adduint(o_string *o, unsigned int i)
826 char *p = simple_itoa(i);
827 /* no escape checking necessary */
828 do r=b_addchr(o, *p++); while (r==0 && *p);
832 static int static_get(struct in_str *i)
835 if (ch=='\0') return EOF;
839 static int static_peek(struct in_str *i)
844 static inline void cmdedit_set_initial_prompt(void)
846 #ifndef BB_FEATURE_SH_FANCY_PROMPT
855 static inline void setup_prompt_string(int promptmode, char **prompt_str)
857 debug_printf("setup_prompt_string %d ",promptmode);
858 #ifndef BB_FEATURE_SH_FANCY_PROMPT
859 /* Set up the prompt */
860 if (promptmode == 1) {
863 PS1=xmalloc(strlen(cwd)+4);
864 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# ");
870 *prompt_str = (promptmode==0)? PS1 : PS2;
872 debug_printf("result %s\n",*prompt_str);
875 static void get_user_input(struct in_str *i)
878 static char the_command[BUFSIZ];
880 setup_prompt_string(i->promptmode, &prompt_str);
881 #ifdef BB_FEATURE_COMMAND_EDITING
883 ** enable command line editing only while a command line
884 ** is actually being read; otherwise, we'll end up bequeathing
885 ** atexit() handlers and other unwanted stuff to our
886 ** child processes (rob@sysgo.de)
888 cmdedit_read_input(prompt_str, the_command);
891 fputs(prompt_str, stdout);
893 the_command[0]=fgetc(i->file);
899 /* This is the magic location that prints prompts
900 * and gets data back from the user */
901 static int file_get(struct in_str *i)
906 /* If there is data waiting, eat it up */
910 /* need to double check i->file because we might be doing something
911 * more complicated by now, like sourcing or substituting. */
912 if (i->__promptme && interactive && i->file == stdin) {
923 debug_printf("b_getch: got a %d\n", ch);
925 if (ch == '\n') i->__promptme=1;
929 /* All the callers guarantee this routine will never be
930 * used right after a newline, so prompting is not needed.
932 static int file_peek(struct in_str *i)
937 static char buffer[2];
938 buffer[0] = fgetc(i->file);
941 debug_printf("b_peek: got a %d\n", *i->p);
946 static void setup_file_in_str(struct in_str *i, FILE *f)
956 static void setup_string_in_str(struct in_str *i, const char *s)
958 i->peek = static_peek;
965 static void mark_open(int fd)
967 struct close_me *new = xmalloc(sizeof(struct close_me));
969 new->next = close_me_head;
973 static void mark_closed(int fd)
975 struct close_me *tmp;
976 if (close_me_head == NULL || close_me_head->fd != fd)
977 error_msg_and_die("corrupt close_me");
979 close_me_head = close_me_head->next;
983 static void close_all()
986 for (c=close_me_head; c; c=c->next) {
989 close_me_head = NULL;
992 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
993 * and stderr if they are redirected. */
994 static int setup_redirects(struct child_prog *prog, int squirrel[])
997 struct redir_struct *redir;
999 for (redir=prog->redirects; redir; redir=redir->next) {
1000 if (redir->dup == -1) {
1001 mode=redir_table[redir->type].mode;
1002 openfd = open(redir->word.gl_pathv[0], mode, 0666);
1004 /* this could get lost if stderr has been redirected, but
1005 bash and ash both lose it as well (though zsh doesn't!) */
1006 perror_msg("error opening %s", redir->word.gl_pathv[0]);
1010 openfd = redir->dup;
1013 if (openfd != redir->fd) {
1014 if (squirrel && redir->fd < 3) {
1015 squirrel[redir->fd] = dup(redir->fd);
1020 dup2(openfd, redir->fd);
1028 static void restore_redirects(int squirrel[])
1031 for (i=0; i<3; i++) {
1034 /* No error checking. I sure wouldn't know what
1035 * to do with an error if I found one! */
1042 /* XXX this definitely needs some more thought, work, and
1043 * cribbing from other shells */
1044 static int pipe_wait(struct pipe *pi)
1046 int rcode=0, i, pid, running, status;
1047 running = pi->num_progs;
1049 pid=waitpid(-1, &status, 0);
1050 if (pid < 0) perror_msg_and_die("waitpid");
1051 for (i=0; i < pi->num_progs; i++) {
1052 if (pi->progs[i].pid == pid) {
1053 if (i==pi->num_progs-1) rcode=WEXITSTATUS(status);
1054 pi->progs[i].pid = 0;
1064 static void pseudo_exec(struct child_prog *child)
1067 struct built_in_command *x;
1069 for (i=0; is_assignment(child->argv[i]); i++) {
1070 debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
1071 putenv(strdup(child->argv[i]));
1073 child->argv+=i; /* XXX this hack isn't so horrible, since we are about
1074 to exit, and therefore don't need to keep data
1075 structures consistent for free() use. */
1076 /* If a variable is assigned in a forest, and nobody listens,
1077 * was it ever really set?
1079 if (child->argv[0] == NULL) exit(EXIT_SUCCESS);
1082 * Check if the command matches any of the builtins.
1083 * Depending on context, this might be redundant. But it's
1084 * easier to waste a few CPU cycles than it is to figure out
1085 * if this is one of those cases.
1087 for (x = bltins; x->cmd; x++) {
1088 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1089 debug_printf("builtin exec %s\n", child->argv[0]);
1090 exit(x->function(child));
1094 /* Check if the command matches any busybox internal commands
1096 * FIXME: This feature is not 100% safe, since
1097 * BusyBox is not fully reentrant, so we have no guarantee the things
1098 * from the .bss are still zeroed, or that things from .data are still
1099 * at their defaults. We could exec ourself from /proc/self/exe, but I
1100 * really dislike relying on /proc for things. We could exec ourself
1101 * from global_argv[0], but if we are in a chroot, we may not be able
1102 * to find ourself... */
1103 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1106 char** argv_l=child->argv;
1107 char *name = child->argv[0];
1109 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1110 /* Following discussions from November 2000 on the busybox mailing
1111 * list, the default configuration, (without
1112 * get_last_path_component()) lets the user force use of an
1113 * external command by specifying the full (with slashes) filename.
1114 * If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then applets
1115 * _aways_ override external commands, so if you want to run
1116 * /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
1117 * filesystem and is _not_ busybox. Some systems may want this,
1119 name = get_last_path_component(name);
1121 /* Count argc for use in a second... */
1122 for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1124 debug_printf("running applet %s\n", name);
1125 run_applet_by_name(name, argc_l, child->argv);
1128 debug_printf("exec of %s\n",child->argv[0]);
1129 execvp(child->argv[0],child->argv);
1130 perror_msg("couldn't exec: %s",child->argv[0]);
1132 } else if (child->group) {
1133 debug_printf("runtime nesting to group\n");
1134 interactive=0; /* crucial!!!! */
1135 rcode = run_list_real(child->group);
1136 /* OK to leak memory by not calling run_list_test,
1137 * since this process is about to exit */
1140 /* Can happen. See what bash does with ">foo" by itself. */
1141 debug_printf("trying to pseudo_exec null command\n");
1146 static void insert_bg_job(struct pipe *pi)
1148 struct pipe *thejob;
1150 /* Linear search for the ID of the job to use */
1152 for (thejob = job_list->head; thejob; thejob = thejob->next)
1153 if (thejob->jobid >= pi->jobid)
1154 pi->jobid = thejob->jobid + 1;
1156 /* add thejob to the list of running jobs */
1157 if (!job_list->head) {
1158 thejob = job_list->head = xmalloc(sizeof(*thejob));
1160 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1161 thejob->next = xmalloc(sizeof(*thejob));
1162 thejob = thejob->next;
1165 /* physically copy the struct job */
1166 memcpy(thejob, pi, sizeof(struct pipe));
1167 thejob->next = NULL;
1168 thejob->running_progs = thejob->num_progs;
1169 thejob->stopped_progs = 0;
1170 thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
1172 //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1174 char *bar=thejob->text;
1175 char **foo=pi->progs[0].argv;
1176 while(foo && *foo) {
1177 bar += sprintf(bar, "%s ", *foo++);
1181 /* we don't wait for background thejobs to return -- append it
1182 to the list of backgrounded thejobs and leave it alone */
1183 printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1184 last_bg_pid = thejob->progs[0].pid;
1187 /* remove a backgrounded job from a jobset */
1188 static void remove_bg_job(struct pipe *pi)
1190 struct pipe *prev_pipe;
1192 if (pi == job_list->head) {
1193 job_list->head = pi->next;
1195 prev_pipe = job_list->head;
1196 while (prev_pipe->next != pi)
1197 prev_pipe = prev_pipe->next;
1198 prev_pipe->next = pi->next;
1205 /* free up all memory from a pipe */
1206 static void free_pipe(struct pipe *pi)
1210 for (i = 0; i < pi->num_progs; i++) {
1211 free(pi->progs[i].argv);
1212 if (pi->progs[i].redirects)
1213 free(pi->progs[i].redirects);
1221 memset(pi, 0, sizeof(struct pipe));
1225 /* Checks to see if any background processes have exited -- if they
1226 have, figure out why and see if a job has completed */
1227 static void checkjobs()
1234 while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
1235 for (pi = job_list->head; pi; pi = pi->next) {
1237 while (prognum < pi->num_progs &&
1238 pi->progs[prognum].pid != childpid) prognum++;
1239 if (prognum < pi->num_progs)
1243 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1245 pi->running_progs--;
1246 pi->progs[prognum].pid = 0;
1248 if (!pi->running_progs) {
1249 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1256 pi->stopped_progs++;
1257 pi->progs[prognum].is_stopped = 1;
1259 if (pi->stopped_progs == pi->num_progs) {
1260 printf(JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
1265 if (childpid == -1 && errno != ECHILD)
1266 perror_msg("waitpid");
1268 /* move the shell to the foreground */
1269 if (interactive && (ctty=controlling_tty(0))!=-1) {
1270 if (tcsetpgrp(ctty, getpgrp()))
1271 perror_msg("tcsetpgrp-2");
1275 /* Figure out our controlling tty, checking in order stderr,
1276 * stdin, and stdout. If check_pgrp is set, also check that
1277 * we belong to the foreground process group associated with
1278 * that tty. The value of ctty is needed in order to call
1279 * tcsetpgrp(ctty, ...); */
1280 int controlling_tty(int check_pgrp)
1285 if ((curpgrp = tcgetpgrp(ctty = 2)) < 0
1286 && (curpgrp = tcgetpgrp(ctty = 0)) < 0
1287 && (curpgrp = tcgetpgrp(ctty = 1)) < 0)
1288 return errno = ENOTTY, -1;
1290 if (check_pgrp && curpgrp != getpgrp())
1291 return errno = EPERM, -1;
1296 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1297 * to finish. See pipe_wait().
1299 * return code is normally -1, when the caller has to wait for children
1300 * to finish to determine the exit status of the pipe. If the pipe
1301 * is a simple builtin command, however, the action is done by the
1302 * time run_pipe_real returns, and the exit code is provided as the
1305 * The input of the pipe is always stdin, the output is always
1306 * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1307 * because it tries to avoid running the command substitution in
1308 * subshell, when that is in fact necessary. The subshell process
1309 * now has its stdout directed to the input of the appropriate pipe,
1310 * so this routine is noticeably simpler.
1312 static int run_pipe_real(struct pipe *pi)
1316 int nextin, nextout;
1317 int pipefds[2]; /* pipefds[0] is for reading */
1318 struct child_prog *child;
1319 struct built_in_command *x;
1325 /* Check if we are supposed to run in the foreground */
1326 if (interactive && pi->followup!=PIPE_BG) {
1327 if ((ctty = controlling_tty(pi->pgrp<0)) < 0) return -1;
1330 /* Check if this is a simple builtin (not part of a pipe).
1331 * Builtins within pipes have to fork anyway, and are handled in
1332 * pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
1334 if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1335 child = & (pi->progs[0]);
1336 if (child->group && ! child->subshell) {
1337 int squirrel[] = {-1, -1, -1};
1339 debug_printf("non-subshell grouping\n");
1340 setup_redirects(child, squirrel);
1341 /* XXX could we merge code with following builtin case,
1342 * by creating a pseudo builtin that calls run_list_real? */
1343 rcode = run_list_real(child->group);
1344 restore_redirects(squirrel);
1347 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1348 if (i!=0 && child->argv[i]==NULL) {
1349 /* assignments, but no command: set the local environment */
1350 for (i=0; child->argv[i]!=NULL; i++) {
1351 set_local_var(child->argv[i], 0);
1353 return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */
1355 for (x = bltins; x->cmd; x++) {
1356 if (strcmp(child->argv[i], x->cmd) == 0 ) {
1357 int squirrel[] = {-1, -1, -1};
1359 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1360 debug_printf("magic exec\n");
1361 setup_redirects(child,NULL);
1362 return EXIT_SUCCESS;
1364 debug_printf("builtin inline %s\n", child->argv[0]);
1365 /* XXX setup_redirects acts on file descriptors, not FILEs.
1366 * This is perfect for work that comes after exec().
1367 * Is it really safe for inline use? Experimentally,
1368 * things seem to work with glibc. */
1369 setup_redirects(child, squirrel);
1370 for (i=0; is_assignment(child->argv[i]); i++) {
1371 putenv(strdup(child->argv[i]));
1373 child->argv+=i; /* XXX horrible hack */
1374 rcode = x->function(child);
1375 child->argv-=i; /* XXX restore hack so free() can work right */
1376 restore_redirects(squirrel);
1382 for (i = 0; i < pi->num_progs; i++) {
1383 child = & (pi->progs[i]);
1385 /* pipes are inserted between pairs of commands */
1386 if ((i + 1) < pi->num_progs) {
1387 if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1388 nextout = pipefds[1];
1394 /* XXX test for failed fork()? */
1395 if (!(child->pid = fork())) {
1397 signal(SIGTTOU, SIG_DFL);
1409 if (pipefds[0]!=-1) {
1410 close(pipefds[0]); /* opposite end of our output pipe */
1413 /* Like bash, explicit redirects override pipes,
1414 * and the pipe fd is available for dup'ing. */
1415 setup_redirects(child,NULL);
1417 if (interactive && pi->followup!=PIPE_BG) {
1418 /* If we (the child) win the race, put ourselves in the process
1419 * group whose leader is the first process in this pipe. */
1421 pi->pgrp = getpid();
1423 if (setpgid(0, pi->pgrp) == 0) {
1424 signal(SIGTTOU, SIG_IGN);
1425 tcsetpgrp(ctty, pi->pgrp);
1426 signal(SIGTTOU, SIG_DFL);
1432 /* Put our child in the process group whose leader is the
1433 * first process in this pipe. */
1435 pi->pgrp = child->pid;
1437 /* Don't check for errors. The child may be dead already,
1438 * in which case setpgid returns error code EACCES. */
1439 setpgid(child->pid, pi->pgrp);
1446 /* If there isn't another process, nextin is garbage
1447 but it doesn't matter */
1448 nextin = pipefds[0];
1453 static int run_list_real(struct pipe *pi)
1456 int if_code=0, next_if_code=0; /* need double-buffer to handle elif */
1457 reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1458 for (;pi;pi=pi->next) {
1460 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);
1461 if (rmode == skip_more_in_this_rmode) continue;
1462 skip_more_in_this_rmode = RES_XXXX;
1463 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1464 if (rmode == RES_THEN && if_code) continue;
1465 if (rmode == RES_ELSE && !if_code) continue;
1466 if (rmode == RES_ELIF && !if_code) continue;
1467 if (pi->num_progs == 0) continue;
1468 rcode = run_pipe_real(pi);
1470 /* We only ran a builtin: rcode was set by the return value
1471 * of run_pipe_real(), and we don't need to wait for anything. */
1472 } else if (pi->followup==PIPE_BG) {
1473 /* XXX check bash's behavior with nontrivial pipes */
1474 /* XXX compute jobid */
1475 /* XXX what does bash do with attempts to background builtins? */
1477 rcode = EXIT_SUCCESS;
1481 /* move the new process group into the foreground */
1482 /* suppress messages when run from /linuxrc mag@sysgo.de */
1483 /* XXX probably this "0" should come from controlling_tty() */
1484 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
1485 perror_msg("tcsetpgrp-3");
1486 rcode = pipe_wait(pi);
1487 if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
1488 perror_msg("tcsetpgrp-4");
1490 rcode = pipe_wait(pi);
1491 debug_printf("pipe_wait returned %d\n",rcode);
1494 last_return_code=rcode;
1495 if ( rmode == RES_IF || rmode == RES_ELIF )
1496 next_if_code=rcode; /* can be overwritten a number of times */
1497 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1498 (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1499 skip_more_in_this_rmode=rmode;
1505 /* broken, of course, but OK for testing */
1506 static char *indenter(int i)
1508 static char blanks[]=" ";
1509 return &blanks[sizeof(blanks)-i-1];
1512 /* return code is the exit status of the pipe */
1513 static int run_pipe_test(struct pipe *pi, int indent)
1516 struct child_prog *child;
1517 struct redir_struct *r, *rnext;
1518 int a, i, ret_code=0;
1519 char *ind = indenter(indent);
1520 final_printf("%s run pipe: (pid %d)\n",ind,getpid());
1521 for (i=0; i<pi->num_progs; i++) {
1522 child = &pi->progs[i];
1523 final_printf("%s command %d:\n",ind,i);
1525 for (a=0,p=child->argv; *p; a++,p++) {
1526 final_printf("%s argv[%d] = %s\n",ind,a,*p);
1528 globfree(&child->glob_result);
1530 } else if (child->group) {
1531 final_printf("%s begin group (subshell:%d)\n",ind, child->subshell);
1532 ret_code = run_list_test(child->group,indent+3);
1533 final_printf("%s end group\n",ind);
1535 final_printf("%s (nil)\n",ind);
1537 for (r=child->redirects; r; r=rnext) {
1538 final_printf("%s redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
1540 final_printf(" %s\n", *r->word.gl_pathv);
1543 final_printf("&%d\n", r->dup);
1548 child->redirects=NULL;
1550 free(pi->progs); /* children are an array, they get freed all at once */
1555 static int run_list_test(struct pipe *head, int indent)
1557 int rcode=0; /* if list has no members */
1558 struct pipe *pi, *next;
1559 char *ind = indenter(indent);
1560 for (pi=head; pi; pi=next) {
1561 if (pi->num_progs == 0) break;
1562 final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
1563 rcode = run_pipe_test(pi, indent);
1564 final_printf("%s pipe followup code %d\n", ind, pi->followup);
1572 /* Select which version we will use */
1573 static int run_list(struct pipe *pi)
1577 rcode = run_list_real(pi);
1579 /* run_list_test has the side effect of clearing memory
1580 * In the long run that function can be merged with run_list_real,
1581 * but doing that now would hobble the debugging effort. */
1582 run_list_test(pi,0);
1586 /* The API for glob is arguably broken. This routine pushes a non-matching
1587 * string into the output structure, removing non-backslashed backslashes.
1588 * If someone can prove me wrong, by performing this function within the
1589 * original glob(3) api, feel free to rewrite this routine into oblivion.
1590 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1591 * XXX broken if the last character is '\\', check that before calling.
1593 static int globhack(const char *src, int flags, glob_t *pglob)
1598 for (cnt=1, s=src; *s; s++) {
1599 if (*s == '\\') s++;
1603 if (!dest) return GLOB_NOSPACE;
1604 if (!(flags & GLOB_APPEND)) {
1605 pglob->gl_pathv=NULL;
1610 pathc = ++pglob->gl_pathc;
1611 pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1612 if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1613 pglob->gl_pathv[pathc-1]=dest;
1614 pglob->gl_pathv[pathc]=NULL;
1615 for (s=src; *s; s++, dest++) {
1616 if (*s == '\\') s++;
1623 /* XXX broken if the last character is '\\', check that before calling */
1624 static int glob_needed(const char *s)
1627 if (*s == '\\') s++;
1628 if (strchr("*[?",*s)) return 1;
1634 static void globprint(glob_t *pglob)
1637 debug_printf("glob_t at %p:\n", pglob);
1638 debug_printf(" gl_pathc=%d gl_pathv=%p gl_offs=%d gl_flags=%d\n",
1639 pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
1640 for (i=0; i<pglob->gl_pathc; i++)
1641 debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
1642 pglob->gl_pathv[i], pglob->gl_pathv[i]);
1646 static int xglob(o_string *dest, int flags, glob_t *pglob)
1650 /* short-circuit for null word */
1651 /* we can code this better when the debug_printf's are gone */
1652 if (dest->length == 0) {
1653 if (dest->nonnull) {
1654 /* bash man page calls this an "explicit" null */
1655 gr = globhack(dest->data, flags, pglob);
1656 debug_printf("globhack returned %d\n",gr);
1660 } else if (glob_needed(dest->data)) {
1661 gr = glob(dest->data, flags, NULL, pglob);
1662 debug_printf("glob returned %d\n",gr);
1663 if (gr == GLOB_NOMATCH) {
1664 /* quote removal, or more accurately, backslash removal */
1665 gr = globhack(dest->data, flags, pglob);
1666 debug_printf("globhack returned %d\n",gr);
1669 gr = globhack(dest->data, flags, pglob);
1670 debug_printf("globhack returned %d\n",gr);
1672 if (gr == GLOB_NOSPACE)
1673 error_msg_and_die("out of memory during glob");
1674 if (gr != 0) { /* GLOB_ABORTED ? */
1675 error_msg("glob(3) error %d",gr);
1677 /* globprint(glob_target); */
1681 /* This is used to get/check local shell variables */
1682 static char *get_local_var(const char *s)
1684 struct variables *cur;
1688 for (cur = top_vars; cur; cur=cur->next)
1689 if(strcmp(cur->name, s)==0)
1694 /* This is used to set local shell variables
1695 flg_export==0 if only local (not exporting) variable
1696 flg_export==1 if "new" exporting environ
1697 flg_export>1 if current startup environ (not call putenv()) */
1698 static int set_local_var(const char *s, int flg_export)
1702 struct variables *cur;
1707 /* Assume when we enter this function that we are already in
1708 * NAME=VALUE format. So the first order of business is to
1709 * split 's' on the '=' into 'name' and 'value' */
1710 value = strchr(name, '=');
1711 if (value==0 || (newval = strdup(value+1))==0) {
1716 for(cur = top_vars; cur; cur = cur->next)
1717 if(strcmp(cur->name, name)==0)
1721 if(strcmp(cur->value, value)==0) {
1722 result = cur->flg_export == flg_export;
1724 if(cur->flg_read_only) {
1726 error_msg("%s: readonly variable", name);
1729 cur->value = newval;
1730 newval = 0; /* protect free */
1734 cur = malloc(sizeof(struct variables));
1738 cur->name = strdup(name);
1739 if(cur->name == 0) {
1743 struct variables *bottom = top_vars;
1745 cur->value = newval;
1746 newval = 0; /* protect free */
1748 cur->flg_export = flg_export;
1749 cur->flg_read_only = 0;
1750 while(bottom->next) bottom=bottom->next;
1757 if((result==0 && flg_export==1) || (result>0 && cur->flg_export>0)) {
1759 result = putenv(name);
1762 if(result>0) /* equivalent to previous set */
1769 static void unset_local_var(const char *name)
1771 struct variables *cur;
1774 for (cur = top_vars; cur; cur=cur->next)
1775 if(strcmp(cur->name, name)==0)
1778 struct variables *next = top_vars;
1783 unsetenv(cur->name);
1786 while (next->next != cur)
1788 next->next = cur->next;
1795 static int is_assignment(const char *s)
1797 if (s==NULL || !isalpha(*s)) return 0;
1799 while(isalnum(*s) || *s=='_') ++s;
1803 /* the src parameter allows us to peek forward to a possible &n syntax
1804 * for file descriptor duplication, e.g., "2>&1".
1805 * Return code is 0 normally, 1 if a syntax error is detected in src.
1806 * Resource errors (in xmalloc) cause the process to exit */
1807 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1808 struct in_str *input)
1810 struct child_prog *child=ctx->child;
1811 struct redir_struct *redir = child->redirects;
1812 struct redir_struct *last_redir=NULL;
1814 /* Create a new redir_struct and drop it onto the end of the linked list */
1819 redir = xmalloc(sizeof(struct redir_struct));
1822 last_redir->next=redir;
1824 child->redirects=redir;
1828 redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1830 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1832 /* Check for a '2>&1' type redirect */
1833 redir->dup = redirect_dup_num(input);
1834 if (redir->dup == -2) return 1; /* syntax error */
1835 if (redir->dup != -1) {
1836 /* Erik had a check here that the file descriptor in question
1837 * is legit; I postpone that to "run time"
1838 * A "-" representation of "close me" shows up as a -3 here */
1839 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1841 /* We do _not_ try to open the file that src points to,
1842 * since we need to return and let src be expanded first.
1843 * Set ctx->pending_redirect, so we know what to do at the
1844 * end of the next parsed word.
1846 ctx->pending_redirect = redir;
1851 struct pipe *new_pipe(void) {
1853 pi = xmalloc(sizeof(struct pipe));
1857 pi->followup = 0; /* invalid */
1861 static void initialize_context(struct p_context *ctx)
1864 ctx->pending_redirect=NULL;
1866 ctx->list_head=new_pipe();
1867 ctx->pipe=ctx->list_head;
1870 done_command(ctx); /* creates the memory for working child */
1873 /* normal return is 0
1874 * if a reserved word is found, and processed, return 1
1875 * should handle if, then, elif, else, fi, for, while, until, do, done.
1876 * case, function, and select are obnoxious, save those for later.
1878 int reserved_word(o_string *dest, struct p_context *ctx)
1880 struct reserved_combo {
1885 /* Mostly a list of accepted follow-up reserved words.
1886 * FLAG_END means we are done with the sequence, and are ready
1887 * to turn the compound list into a command.
1888 * FLAG_START means the word must start a new compound list.
1890 static struct reserved_combo reserved_list[] = {
1891 { "if", RES_IF, FLAG_THEN | FLAG_START },
1892 { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
1893 { "elif", RES_ELIF, FLAG_THEN },
1894 { "else", RES_ELSE, FLAG_FI },
1895 { "fi", RES_FI, FLAG_END },
1896 { "for", RES_FOR, FLAG_DO | FLAG_START },
1897 { "while", RES_WHILE, FLAG_DO | FLAG_START },
1898 { "until", RES_UNTIL, FLAG_DO | FLAG_START },
1899 { "do", RES_DO, FLAG_DONE },
1900 { "done", RES_DONE, FLAG_END }
1902 struct reserved_combo *r;
1903 for (r=reserved_list;
1904 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
1905 r<reserved_list+NRES; r++) {
1906 if (strcmp(dest->data, r->literal) == 0) {
1907 debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
1908 if (r->flag & FLAG_START) {
1909 struct p_context *new = xmalloc(sizeof(struct p_context));
1910 debug_printf("push stack\n");
1911 *new = *ctx; /* physical copy */
1912 initialize_context(ctx);
1914 } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
1921 ctx->old_flag = r->flag;
1922 if (ctx->old_flag & FLAG_END) {
1923 struct p_context *old;
1924 debug_printf("pop stack\n");
1926 old->child->group = ctx->list_head;
1927 *ctx = *old; /* physical copy */
1937 /* normal return is 0.
1938 * Syntax or xglob errors return 1. */
1939 static int done_word(o_string *dest, struct p_context *ctx)
1941 struct child_prog *child=ctx->child;
1942 glob_t *glob_target;
1945 debug_printf("done_word: %s %p\n", dest->data, child);
1946 if (dest->length == 0 && !dest->nonnull) {
1947 debug_printf(" true null, ignored\n");
1950 if (ctx->pending_redirect) {
1951 glob_target = &ctx->pending_redirect->word;
1955 return 1; /* syntax error, groups and arglists don't mix */
1958 debug_printf("checking %s for reserved-ness\n",dest->data);
1959 if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
1961 glob_target = &child->glob_result;
1962 if (child->argv) flags |= GLOB_APPEND;
1964 gr = xglob(dest, flags, glob_target);
1965 if (gr != 0) return 1;
1968 if (ctx->pending_redirect) {
1969 ctx->pending_redirect=NULL;
1970 if (glob_target->gl_pathc != 1) {
1971 error_msg("ambiguous redirect");
1975 child->argv = glob_target->gl_pathv;
1980 /* The only possible error here is out of memory, in which case
1982 static int done_command(struct p_context *ctx)
1984 /* The child is really already in the pipe structure, so
1985 * advance the pipe counter and make a new, null child.
1986 * Only real trickiness here is that the uncommitted
1987 * child structure, to which ctx->child points, is not
1988 * counted in pi->num_progs. */
1989 struct pipe *pi=ctx->pipe;
1990 struct child_prog *prog=ctx->child;
1992 if (prog && prog->group == NULL
1993 && prog->argv == NULL
1994 && prog->redirects == NULL) {
1995 debug_printf("done_command: skipping null command\n");
1999 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
2001 debug_printf("done_command: initializing\n");
2003 pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2005 prog = pi->progs + pi->num_progs;
2006 prog->redirects = NULL;
2008 prog->is_stopped = 0;
2010 prog->glob_result.gl_pathv = NULL;
2014 /* but ctx->pipe and ctx->list_head remain unchanged */
2018 static int done_pipe(struct p_context *ctx, pipe_style type)
2021 done_command(ctx); /* implicit closure of previous command */
2022 debug_printf("done_pipe, type %d\n", type);
2023 ctx->pipe->followup = type;
2024 ctx->pipe->r_mode = ctx->w;
2026 ctx->pipe->next = new_p;
2029 done_command(ctx); /* set up new pipe to accept commands */
2033 /* peek ahead in the in_str to find out if we have a "&n" construct,
2034 * as in "2>&1", that represents duplicating a file descriptor.
2035 * returns either -2 (syntax error), -1 (no &), or the number found.
2037 static int redirect_dup_num(struct in_str *input)
2041 if (ch != '&') return -1;
2043 b_getch(input); /* get the & */
2047 return -3; /* "-" represents "close me" */
2049 while (isdigit(ch)) {
2057 error_msg("ambiguous redirect");
2061 /* If a redirect is immediately preceded by a number, that number is
2062 * supposed to tell which file descriptor to redirect. This routine
2063 * looks for such preceding numbers. In an ideal world this routine
2064 * needs to handle all the following classes of redirects...
2065 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
2066 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
2067 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
2068 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
2069 * A -1 output from this program means no valid number was found, so the
2070 * caller should use the appropriate default for this redirection.
2072 static int redirect_opt_num(o_string *o)
2076 if (o->length==0) return -1;
2077 for(num=0; num<o->length; num++) {
2078 if (!isdigit(*(o->data+num))) {
2082 /* reuse num (and save an int) */
2088 FILE *generate_stream_from_list(struct pipe *head)
2092 int pid, channel[2];
2093 if (pipe(channel)<0) perror_msg_and_die("pipe");
2096 perror_msg_and_die("fork");
2097 } else if (pid==0) {
2099 if (channel[1] != 1) {
2104 #define SURROGATE "surrogate response"
2105 write(1,SURROGATE,sizeof(SURROGATE));
2106 exit(run_list(head));
2108 exit(run_list_real(head)); /* leaks memory */
2111 debug_printf("forked child %d\n",pid);
2113 pf = fdopen(channel[0],"r");
2114 debug_printf("pipe on FILE *%p\n",pf);
2116 run_list_test(head,0);
2117 pf=popen("echo surrogate response","r");
2118 debug_printf("started fake pipe on FILE *%p\n",pf);
2123 /* this version hacked for testing purposes */
2124 /* return code is exit status of the process that is run. */
2125 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2128 o_string result=NULL_O_STRING;
2129 struct p_context inner;
2131 struct in_str pipe_str;
2132 initialize_context(&inner);
2134 /* recursion to generate command */
2135 retcode = parse_stream(&result, &inner, input, subst_end);
2136 if (retcode != 0) return retcode; /* syntax error or EOF */
2137 done_word(&result, &inner);
2138 done_pipe(&inner, PIPE_SEQ);
2141 p=generate_stream_from_list(inner.list_head);
2142 if (p==NULL) return 1;
2143 mark_open(fileno(p));
2144 setup_file_in_str(&pipe_str, p);
2146 /* now send results of command back into original context */
2147 retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2148 /* XXX In case of a syntax error, should we try to kill the child?
2149 * That would be tough to do right, so just read until EOF. */
2151 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2154 debug_printf("done reading from pipe, pclose()ing\n");
2155 /* This is the step that wait()s for the child. Should be pretty
2156 * safe, since we just read an EOF from its stdout. We could try
2157 * to better, by using wait(), and keeping track of background jobs
2158 * at the same time. That would be a lot of work, and contrary
2159 * to the KISS philosophy of this program. */
2160 mark_closed(fileno(p));
2162 debug_printf("pclosed, retcode=%d\n",retcode);
2163 /* XXX this process fails to trim a single trailing newline */
2167 static int parse_group(o_string *dest, struct p_context *ctx,
2168 struct in_str *input, int ch)
2171 struct p_context sub;
2172 struct child_prog *child = ctx->child;
2175 return 1; /* syntax error, groups and arglists don't mix */
2177 initialize_context(&sub);
2179 case '(': endch=')'; child->subshell=1; break;
2180 case '{': endch='}'; break;
2181 default: syntax(); /* really logic error */
2183 rcode=parse_stream(dest,&sub,input,endch);
2184 done_word(dest,&sub); /* finish off the final word in the subcontext */
2185 done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
2186 child->group = sub.list_head;
2188 /* child remains "open", available for possible redirects */
2191 /* basically useful version until someone wants to get fancier,
2192 * see the bash man page under "Parameter Expansion" */
2193 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src)
2197 p = getenv(src->data);
2199 p = get_local_var(src->data);
2201 if (p) parse_string(dest, ctx, p); /* recursion */
2205 /* return code: 0 for OK, 1 for syntax error */
2206 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2209 o_string alt=NULL_O_STRING;
2211 int ch = input->peek(input); /* first character after the $ */
2212 debug_printf("handle_dollar: ch=%c\n",ch);
2214 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2218 lookup_param(dest, ctx, &alt);
2219 } else if (isdigit(ch)) {
2220 i = ch-'0'; /* XXX is $0 special? */
2221 if (i<global_argc) {
2222 parse_string(dest, ctx, global_argv[i]); /* recursion */
2225 } else switch (ch) {
2227 b_adduint(dest,getpid());
2231 if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2235 b_adduint(dest,last_return_code);
2239 b_adduint(dest,global_argc ? global_argc-1 : 0);
2244 /* XXX maybe someone will try to escape the '}' */
2245 while(ch=b_getch(input),ch!=EOF && ch!='}') {
2252 lookup_param(dest, ctx, &alt);
2256 process_command_subs(dest, ctx, input, ')');
2260 for (i=1; i<global_argc; i++) {
2261 parse_string(dest, ctx, global_argv[i]);
2262 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2268 /* still unhandled, but should be eventually */
2269 error_msg("unhandled syntax: $%c",ch);
2273 b_addqchr(dest,'$',dest->quote);
2275 /* Eat the character if the flag was set. If the compiler
2276 * is smart enough, we could substitute "b_getch(input);"
2277 * for all the "advance = 1;" above, and also end up with
2278 * a nice size-optimized program. Hah! That'll be the day.
2280 if (advance) b_getch(input);
2284 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2287 setup_string_in_str(&foo, src);
2288 return parse_stream(dest, ctx, &foo, '\0');
2291 /* return code is 0 for normal exit, 1 for syntax error */
2292 int parse_stream(o_string *dest, struct p_context *ctx,
2293 struct in_str *input, int end_trigger)
2297 redir_type redir_style;
2300 /* Only double-quote state is handled in the state variable dest->quote.
2301 * A single-quote triggers a bypass of the main loop until its mate is
2302 * found. When recursing, quote state is passed in via dest->quote. */
2304 debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2305 while ((ch=b_getch(input))!=EOF) {
2307 next = (ch == '\n') ? 0 : b_peek(input);
2308 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2309 ch,ch,m,dest->quote);
2310 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2311 b_addqchr(dest, ch, dest->quote);
2313 if (m==2) { /* unquoted IFS */
2314 done_word(dest, ctx);
2315 /* If we aren't performing a substitution, treat a newline as a
2316 * command separator. */
2317 if (end_trigger != '\0' && ch=='\n')
2318 done_pipe(ctx,PIPE_SEQ);
2320 if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2321 debug_printf("leaving parse_stream\n");
2326 /* Yahoo! Time to run with it! */
2327 done_pipe(ctx,PIPE_SEQ);
2328 run_list(ctx->list_head);
2329 initialize_context(ctx);
2332 if (m!=2) switch (ch) {
2334 if (dest->length == 0 && !dest->quote) {
2335 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2337 b_addqchr(dest, ch, dest->quote);
2345 b_addqchr(dest, '\\', dest->quote);
2346 b_addqchr(dest, b_getch(input), dest->quote);
2349 if (handle_dollar(dest, ctx, input)!=0) return 1;
2353 while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2363 dest->quote = !dest->quote;
2366 process_command_subs(dest, ctx, input, '`');
2369 redir_fd = redirect_opt_num(dest);
2370 done_word(dest, ctx);
2371 redir_style=REDIRECT_OVERWRITE;
2373 redir_style=REDIRECT_APPEND;
2375 } else if (next == '(') {
2376 syntax(); /* until we support >(list) Process Substitution */
2379 setup_redirect(ctx, redir_fd, redir_style, input);
2382 redir_fd = redirect_opt_num(dest);
2383 done_word(dest, ctx);
2384 redir_style=REDIRECT_INPUT;
2386 redir_style=REDIRECT_HEREIS;
2388 } else if (next == '>') {
2389 redir_style=REDIRECT_IO;
2391 } else if (next == '(') {
2392 syntax(); /* until we support <(list) Process Substitution */
2395 setup_redirect(ctx, redir_fd, redir_style, input);
2398 done_word(dest, ctx);
2399 done_pipe(ctx,PIPE_SEQ);
2402 done_word(dest, ctx);
2405 done_pipe(ctx,PIPE_AND);
2407 done_pipe(ctx,PIPE_BG);
2411 done_word(dest, ctx);
2414 done_pipe(ctx,PIPE_OR);
2416 /* we could pick up a file descriptor choice here
2417 * with redirect_opt_num(), but bash doesn't do it.
2418 * "echo foo 2| cat" yields "foo 2". */
2424 if (parse_group(dest, ctx, input, ch)!=0) return 1;
2428 syntax(); /* Proper use of this character caught by end_trigger */
2432 syntax(); /* this is really an internal logic error */
2437 /* complain if quote? No, maybe we just finished a command substitution
2438 * that was quoted. Example:
2439 * $ echo "`cat foo` plus more"
2440 * and we just got the EOF generated by the subshell that ran "cat foo"
2441 * The only real complaint is if we got an EOF when end_trigger != '\0',
2442 * that is, we were really supposed to get end_trigger, and never got
2443 * one before the EOF. Can't use the standard "syntax error" return code,
2444 * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2445 if (end_trigger != '\0') return -1;
2449 void mapset(const unsigned char *set, int code)
2451 const unsigned char *s;
2452 for (s=set; *s; s++) map[*s] = code;
2455 void update_ifs_map(void)
2457 /* char *ifs and char map[256] are both globals. */
2458 ifs = getenv("IFS");
2459 if (ifs == NULL) ifs=" \t\n";
2460 /* Precompute a list of 'flow through' behavior so it can be treated
2461 * quickly up front. Computation is necessary because of IFS.
2462 * Special case handling of IFS == " \t\n" is not implemented.
2463 * The map[] array only really needs two bits each, and on most machines
2464 * that would be faster because of the reduced L1 cache footprint.
2466 memset(map,0,256); /* most characters flow through always */
2467 mapset("\\$'\"`", 3); /* never flow through */
2468 mapset("<>;&|(){}#", 1); /* flow through if quoted */
2469 mapset(ifs, 2); /* also flow through if quoted */
2472 /* most recursion does not come through here, the exeception is
2473 * from builtin_source() */
2474 int parse_stream_outer(struct in_str *inp)
2477 struct p_context ctx;
2478 o_string temp=NULL_O_STRING;
2481 initialize_context(&ctx);
2484 rcode = parse_stream(&temp, &ctx, inp, '\n');
2485 done_word(&temp, &ctx);
2486 done_pipe(&ctx,PIPE_SEQ);
2487 run_list(ctx.list_head);
2488 } while (rcode != -1); /* loop on syntax errors, return on EOF */
2492 static int parse_string_outer(const char *s)
2494 struct in_str input;
2495 setup_string_in_str(&input, s);
2496 return parse_stream_outer(&input);
2499 static int parse_file_outer(FILE *f)
2502 struct in_str input;
2503 setup_file_in_str(&input, f);
2504 rcode = parse_stream_outer(&input);
2509 /* I think Erik wrote this. It looks imperfect at best */
2510 void grab_tty_control(void)
2514 initialpgrp = tcgetpgrp(fileno(stderr));
2515 if (initialpgrp < 0) {
2516 error_msg("sh: can't access tty; job control disabled\n");
2518 if (initialpgrp == -1)
2519 initialpgrp = getpgrp();
2520 else if (initialpgrp != getpgrp()) {
2521 killpg(initialpgrp, SIGTTIN);
2527 int shell_main(int argc, char **argv)
2531 struct jobset joblist_end = { NULL, NULL };
2534 /* initialize globals */
2537 set_local_var(*e, 2); /* without call putenv() */
2539 job_list = &joblist_end;
2541 last_return_code=EXIT_SUCCESS;
2543 /* XXX what should these be while sourcing /etc/profile? */
2547 /* If we get started under a job aware app (like bash
2548 * for example), make sure we are now in charge so we
2549 * don't fight over who gets the foreground */
2550 /* don't pay any attention to this signal; it just confuses
2551 things and isn't really meant for shells anyway */
2552 signal(SIGTTOU, SIG_IGN);
2553 setpgid(0, getpid());
2554 tcsetpgrp(fileno(stderr), getpid());
2556 if (argv[0] && argv[0][0] == '-') {
2557 debug_printf("\nsourcing /etc/profile\n");
2558 input = xfopen("/etc/profile", "r");
2559 mark_open(fileno(input));
2560 parse_file_outer(input);
2561 mark_closed(fileno(input));
2566 /* initialize the cwd -- this is never freed...*/
2570 #ifdef BB_FEATURE_COMMAND_EDITING
2571 cmdedit_set_initial_prompt();
2576 while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2580 global_argv = argv+optind;
2581 global_argc = argc-optind;
2582 opt = parse_string_outer(optarg);
2594 fprintf(stderr, "Usage: sh [FILE]...\n"
2595 " or: sh -c command [args]...\n\n");
2602 /* A shell is interactive if the `-i' flag was given, or if all of
2603 * the following conditions are met:
2605 * no arguments remaining or the -s flag given
2606 * standard input is a terminal
2607 * standard output is a terminal
2608 * Refer to Posix.2, the description of the `sh' utility. */
2609 if (argv[optind]==NULL && input==stdin &&
2610 isatty(fileno(stdin)) && isatty(fileno(stdout))) {
2614 debug_printf("\ninteractive=%d\n", interactive);
2616 /* Looks like they want an interactive shell */
2617 fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n");
2620 if (argv[optind]==NULL) {
2621 opt=parse_file_outer(stdin);
2625 debug_printf("\nrunning script '%s'\n", argv[optind]);
2626 global_argv = argv+optind;
2627 global_argc = argc-optind;
2628 input = xfopen(argv[optind], "r");
2629 opt = parse_file_outer(input);
2631 #ifdef BB_FEATURE_CLEAN_UP
2636 return(opt?opt:last_return_code);