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
46 * Arithmetic Expansion
47 * <(list) and >(list) Process Substitution
48 * reserved words: case, esac, select, function
49 * Here Documents ( << word )
52 * job handling woefully incomplete and buggy
53 * reserved word execution woefully incomplete and buggy
55 * port selected bugfixes from post-0.49 busybox lash - done?
56 * finish implementing reserved words: for, while, until, do, done
57 * change { and } from special chars to reserved words
58 * builtins: break, continue, eval, return, set, trap, ulimit
60 * handle children going into background
61 * clean up recognition of null pipes
62 * have builtin_exec set flag to avoid restore_redirects
63 * check setting of global_argc and global_argv
64 * control-C handling, probably with longjmp
65 * VAR=value prefix for simple commands
66 * follow IFS rules more precisely, including update semantics
67 * figure out what to do with backslash-newline
68 * explain why we use signal instead of sigaction
69 * propagate syntax errors, die on resource errors?
70 * continuation lines, both explicit and implicit - done?
71 * memory leak finding and plugging - done?
72 * more testing, especially quoting rules and redirection
73 * 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 #define BB_FEATURE_SH_SIMPLE_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;
230 /* globals, connect us to the outside world
231 * the first three support $?, $#, and $1 */
233 unsigned int global_argc;
234 unsigned int last_return_code;
235 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
237 /* Variables we export */
238 unsigned int shell_context; /* Used in cmdedit.c to reset the
239 * context when someone hits ^C */
241 /* "globals" within this file */
242 static char *ifs=NULL;
243 static char map[256];
244 static int fake_mode=0;
245 static int interactive=0;
246 static struct close_me *close_me_head = NULL;
248 static struct jobset *job_list;
249 static unsigned int last_bg_pid=0;
251 static char *PS2 = "> ";
253 #define B_CHUNK (100)
255 #define MAX_LINE 256 /* for cwd */
256 #define MAX_READ 256 /* for builtin_read */
265 #define NULL_O_STRING {NULL,0,0,0,0}
266 /* used for initialization:
267 o_string foo = NULL_O_STRING; */
269 /* I can almost use ordinary FILE *. Is open_memstream() universally
270 * available? Where is it documented? */
276 int (*get) (struct in_str *);
277 int (*peek) (struct in_str *);
279 #define b_getch(input) ((input)->get(input))
280 #define b_peek(input) ((input)->peek(input))
282 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
284 struct built_in_command {
285 char *cmd; /* name */
286 char *descr; /* description */
287 int (*function) (struct child_prog *); /* function ptr */
290 /* belongs in busybox.h */
291 static inline int max(int a, int b) {
295 /* This should be in utility.c */
297 static void debug_printf(const char *format, ...)
300 va_start(args, format);
301 vfprintf(stderr, format, args);
305 static void debug_printf(const char *format, ...) { }
307 #define final_printf debug_printf
309 void __syntax(char *file, int line) {
310 fprintf(stderr,"syntax error %s:%d\n",file,line);
312 #define syntax() __syntax(__FILE__, __LINE__)
314 /* Index of subroutines: */
315 /* function prototypes for builtins */
316 static int builtin_cd(struct child_prog *child);
317 static int builtin_env(struct child_prog *child);
318 static int builtin_exec(struct child_prog *child);
319 static int builtin_exit(struct child_prog *child);
320 static int builtin_export(struct child_prog *child);
321 static int builtin_fg_bg(struct child_prog *child);
322 static int builtin_help(struct child_prog *child);
323 static int builtin_jobs(struct child_prog *child);
324 static int builtin_pwd(struct child_prog *child);
325 static int builtin_read(struct child_prog *child);
326 static int builtin_shift(struct child_prog *child);
327 static int builtin_source(struct child_prog *child);
328 static int builtin_umask(struct child_prog *child);
329 static int builtin_unset(struct child_prog *child);
330 static int builtin_not_written(struct child_prog *child);
331 /* o_string manipulation: */
332 static int b_check_space(o_string *o, int len);
333 static int b_addchr(o_string *o, int ch);
334 static void b_reset(o_string *o);
335 static int b_addqchr(o_string *o, int ch, int quote);
336 static int b_adduint(o_string *o, unsigned int i);
337 /* in_str manipulations: */
338 static int static_get(struct in_str *i);
339 static int static_peek(struct in_str *i);
340 static int file_get(struct in_str *i);
341 static int file_peek(struct in_str *i);
342 static void setup_file_in_str(struct in_str *i, FILE *f);
343 static void setup_string_in_str(struct in_str *i, const char *s);
344 /* close_me manipulations: */
345 static void mark_open(int fd);
346 static void mark_closed(int fd);
347 static void close_all();
348 /* "run" the final data structures: */
349 static char *indenter(int i);
350 static int run_list_test(struct pipe *head, int indent);
351 static int run_pipe_test(struct pipe *pi, int indent);
352 /* really run the final data structures: */
353 static int setup_redirects(struct child_prog *prog, int squirrel[]);
354 static int pipe_wait(struct pipe *pi);
355 static int run_list_real(struct pipe *pi);
356 static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
357 static int run_pipe_real(struct pipe *pi);
358 /* extended glob support: */
359 static int globhack(const char *src, int flags, glob_t *pglob);
360 static int glob_needed(const char *s);
361 static int xglob(o_string *dest, int flags, glob_t *pglob);
362 /* data structure manipulation: */
363 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
364 static void initialize_context(struct p_context *ctx);
365 static int done_word(o_string *dest, struct p_context *ctx);
366 static int done_command(struct p_context *ctx);
367 static int done_pipe(struct p_context *ctx, pipe_style type);
368 /* primary string parsing: */
369 static int redirect_dup_num(struct in_str *input);
370 static int redirect_opt_num(o_string *o);
371 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
372 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
373 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src);
374 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
375 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
376 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
378 static int parse_stream_outer(struct in_str *inp);
379 static int parse_string_outer(const char *s);
380 static int parse_file_outer(FILE *f);
381 /* job management: */
382 static void checkjobs();
383 static void insert_bg_job(struct pipe *pi);
384 static void remove_bg_job(struct pipe *pi);
385 static void free_pipe(struct pipe *pi);
387 /* Table of built-in functions. They can be forked or not, depending on
388 * context: within pipes, they fork. As simple commands, they do not.
389 * When used in non-forking context, they can change global variables
390 * in the parent shell process. If forked, of course they can not.
391 * For example, 'unset foo | whatever' will parse and run, but foo will
392 * still be set at the end. */
393 static struct built_in_command bltins[] = {
394 {"bg", "Resume a job in the background", builtin_fg_bg},
395 {"break", "Exit for, while or until loop", builtin_not_written},
396 {"cd", "Change working directory", builtin_cd},
397 {"continue", "Continue for, while or until loop", builtin_not_written},
398 {"env", "Print all environment variables", builtin_env},
399 {"eval", "Construct and run shell command", builtin_not_written},
400 {"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
401 {"exit", "Exit from shell()", builtin_exit},
402 {"export", "Set environment variable", builtin_export},
403 {"fg", "Bring job into the foreground", builtin_fg_bg},
404 {"jobs", "Lists the active jobs", builtin_jobs},
405 {"pwd", "Print current directory", builtin_pwd},
406 {"read", "Input environment variable", builtin_read},
407 {"return", "Return from a function", builtin_not_written},
408 {"set", "Set/unset shell options", builtin_not_written},
409 {"shift", "Shift positional parameters", builtin_shift},
410 {"trap", "Trap signals", builtin_not_written},
411 {"ulimit","Controls resource limits", builtin_not_written},
412 {"umask","Sets file creation mask", builtin_umask},
413 {"unset", "Unset environment variable", builtin_unset},
414 {".", "Source-in and run commands in a file", builtin_source},
415 {"help", "List shell built-in commands", builtin_help},
419 /* built-in 'cd <path>' handler */
420 static int builtin_cd(struct child_prog *child)
423 if (child->argv[1] == NULL)
424 newdir = getenv("HOME");
426 newdir = child->argv[1];
428 printf("cd: %s: %s\n", newdir, strerror(errno));
431 getcwd(cwd, sizeof(char)*MAX_LINE);
435 /* built-in 'env' handler */
436 static int builtin_env(struct child_prog *dummy)
439 if (e == NULL) return EXIT_FAILURE;
446 /* built-in 'exec' handler */
447 static int builtin_exec(struct child_prog *child)
449 if (child->argv[1] == NULL)
450 return EXIT_SUCCESS; /* Really? */
456 /* built-in 'exit' handler */
457 static int builtin_exit(struct child_prog *child)
459 if (child->argv[1] == NULL)
460 exit(last_return_code);
461 exit (atoi(child->argv[1]));
464 /* built-in 'export VAR=value' handler */
465 static int builtin_export(struct child_prog *child)
469 if (child->argv[1] == NULL) {
470 return (builtin_env(child));
472 /* FIXME -- I leak memory. This will be
473 * fixed up properly when we add local
474 * variable support -- I hope */
475 res = putenv(strdup(child->argv[1]));
477 fprintf(stderr, "export: %s\n", strerror(errno));
481 /* built-in 'fg' and 'bg' handler */
482 static int builtin_fg_bg(struct child_prog *child)
485 struct pipe *pi=NULL;
487 /* If they gave us no args, assume they want the last backgrounded task */
488 if (!child->argv[1]) {
489 for (pi = job_list->head; pi; pi = pi->next) {
490 if (pi->progs && pi->progs->pid == last_bg_pid) {
495 error_msg("%s: no current job", child->argv[0]);
499 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
500 error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
504 for (pi = job_list->head; pi; pi = pi->next) {
505 if (pi->jobid == jobnum) {
510 error_msg("%s: %d: no such job", child->argv[0], jobnum);
514 if (*child->argv[0] == 'f') {
515 /* Make this job the foreground job */
516 signal(SIGTTOU, SIG_IGN);
517 /* suppress messages when run from /linuxrc mag@sysgo.de */
518 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
519 perror_msg("tcsetpgrp");
520 signal(SIGTTOU, SIG_DFL);
524 /* Restart the processes in the job */
525 for (i = 0; i < pi->num_progs; i++)
526 pi->progs[i].is_stopped = 0;
528 kill(-pi->pgrp, SIGCONT);
530 pi->stopped_progs = 0;
534 /* built-in 'help' handler */
535 static int builtin_help(struct child_prog *dummy)
537 struct built_in_command *x;
539 printf("\nBuilt-in commands:\n");
540 printf("-------------------\n");
541 for (x = bltins; x->cmd; x++) {
544 printf("%s\t%s\n", x->cmd, x->descr);
550 /* built-in 'jobs' handler */
551 static int builtin_jobs(struct child_prog *child)
556 for (job = job_list->head; job; job = job->next) {
557 if (job->running_progs == job->stopped_progs)
558 status_string = "Stopped";
560 status_string = "Running";
561 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
567 /* built-in 'pwd' handler */
568 static int builtin_pwd(struct child_prog *dummy)
570 getcwd(cwd, MAX_LINE);
575 /* built-in 'read VAR' handler */
576 static int builtin_read(struct child_prog *child)
578 int res = 0, len, newlen;
580 char string[MAX_READ];
582 if (child->argv[1]) {
583 /* argument (VAR) given: put "VAR=" into buffer */
584 strcpy(string, child->argv[1]);
585 len = strlen(string);
588 /* XXX would it be better to go through in_str? */
589 fgets(&string[len], sizeof(string) - len, stdin); /* read string */
590 newlen = strlen(string);
592 string[--newlen] = '\0'; /* chomp trailing newline */
594 ** string should now contain "VAR=<value>"
595 ** copy it (putenv() won't do that, so we must make sure
596 ** the string resides in a static buffer!)
599 if((s = strdup(string)))
602 fprintf(stderr, "read: %s\n", strerror(errno));
605 fgets(string, sizeof(string), stdin);
610 /* Built-in 'shift' handler */
611 static int builtin_shift(struct child_prog *child)
614 if (child->argv[1]) {
615 n=atoi(child->argv[1]);
617 if (n>=0 && n<global_argc) {
618 /* XXX This probably breaks $0 */
627 /* Built-in '.' handler (read-in and execute commands from file) */
628 static int builtin_source(struct child_prog *child)
633 if (child->argv[1] == NULL)
636 /* XXX search through $PATH is missing */
637 input = fopen(child->argv[1], "r");
639 fprintf(stderr, "Couldn't open file '%s'\n", child->argv[1]);
643 /* Now run the file */
644 /* XXX argv and argc are broken; need to save old global_argv
645 * (pointer only is OK!) on this stack frame,
646 * set global_argv=child->argv+1, recurse, and restore. */
647 mark_open(fileno(input));
648 status = parse_file_outer(input);
649 mark_closed(fileno(input));
654 static int builtin_umask(struct child_prog *child)
657 const char *arg = child->argv[1];
660 new_umask=strtoul(arg, &end, 8);
661 if (*end!='\0' || end == arg) {
665 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
671 /* built-in 'unset VAR' handler */
672 static int builtin_unset(struct child_prog *child)
674 if (child->argv[1] == NULL) {
675 fprintf(stderr, "unset: parameter required.\n");
678 unsetenv(child->argv[1]);
682 static int builtin_not_written(struct child_prog *child)
684 printf("builtin_%s not written\n",child->argv[0]);
688 static int b_check_space(o_string *o, int len)
690 /* It would be easy to drop a more restrictive policy
691 * in here, such as setting a maximum string length */
692 if (o->length + len > o->maxlen) {
693 char *old_data = o->data;
694 /* assert (data == NULL || o->maxlen != 0); */
695 o->maxlen += max(2*len, B_CHUNK);
696 o->data = realloc(o->data, 1 + o->maxlen);
697 if (o->data == NULL) {
701 return o->data == NULL;
704 static int b_addchr(o_string *o, int ch)
706 debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
707 if (b_check_space(o, 1)) return B_NOSPAC;
708 o->data[o->length] = ch;
710 o->data[o->length] = '\0';
714 static void b_reset(o_string *o)
718 if (o->data != NULL) *o->data = '\0';
721 static void b_free(o_string *o)
724 if (o->data != NULL) free(o->data);
729 /* My analysis of quoting semantics tells me that state information
730 * is associated with a destination, not a source.
732 static int b_addqchr(o_string *o, int ch, int quote)
734 if (quote && strchr("*?[\\",ch)) {
736 rc = b_addchr(o, '\\');
739 return b_addchr(o, ch);
742 /* belongs in utility.c */
743 char *simple_itoa(unsigned int i)
745 /* 21 digits plus null terminator, good for 64-bit or smaller ints */
746 static char local[22];
747 char *p = &local[21];
756 static int b_adduint(o_string *o, unsigned int i)
759 char *p = simple_itoa(i);
760 /* no escape checking necessary */
761 do r=b_addchr(o, *p++); while (r==0 && *p);
765 static int static_get(struct in_str *i)
768 if (ch=='\0') return EOF;
772 static int static_peek(struct in_str *i)
777 static inline void cmdedit_set_initial_prompt(void)
779 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
788 static inline void setup_prompt_string(int promptmode, char **prompt_str)
790 debug_printf("setup_prompt_string %d ",promptmode);
791 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
792 /* Set up the prompt */
793 if (promptmode == 1) {
796 PS1=xmalloc(strlen(cwd)+4);
797 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# ");
803 *prompt_str = (promptmode==0)? PS1 : PS2;
805 debug_printf("result %s\n",*prompt_str);
808 static void get_user_input(struct in_str *i)
811 static char the_command[BUFSIZ];
813 setup_prompt_string(i->promptmode, &prompt_str);
814 #ifdef BB_FEATURE_COMMAND_EDITING
816 ** enable command line editing only while a command line
817 ** is actually being read; otherwise, we'll end up bequeathing
818 ** atexit() handlers and other unwanted stuff to our
819 ** child processes (rob@sysgo.de)
821 cmdedit_read_input(prompt_str, the_command);
824 fputs(prompt_str, stdout);
826 the_command[0]=fgetc(i->file);
832 /* This is the magic location that prints prompts
833 * and gets data back from the user */
834 static int file_get(struct in_str *i)
839 /* If there is data waiting, eat it up */
843 /* need to double check i->file because we might be doing something
844 * more complicated by now, like sourcing or substituting. */
845 if (i->__promptme && interactive && i->file == stdin) {
856 debug_printf("b_getch: got a %d\n", ch);
858 if (ch == '\n') i->__promptme=1;
862 /* All the callers guarantee this routine will never be
863 * used right after a newline, so prompting is not needed.
865 static int file_peek(struct in_str *i)
870 static char buffer[2];
871 buffer[0] = fgetc(i->file);
874 debug_printf("b_peek: got a %d\n", *i->p);
879 static void setup_file_in_str(struct in_str *i, FILE *f)
889 static void setup_string_in_str(struct in_str *i, const char *s)
891 i->peek = static_peek;
898 static void mark_open(int fd)
900 struct close_me *new = xmalloc(sizeof(struct close_me));
902 new->next = close_me_head;
906 static void mark_closed(int fd)
908 struct close_me *tmp;
909 if (close_me_head == NULL || close_me_head->fd != fd)
910 error_msg_and_die("corrupt close_me");
912 close_me_head = close_me_head->next;
916 static void close_all()
919 for (c=close_me_head; c; c=c->next) {
922 close_me_head = NULL;
925 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
926 * and stderr if they are redirected. */
927 static int setup_redirects(struct child_prog *prog, int squirrel[])
930 struct redir_struct *redir;
932 for (redir=prog->redirects; redir; redir=redir->next) {
933 if (redir->dup == -1) {
934 mode=redir_table[redir->type].mode;
935 openfd = open(redir->word.gl_pathv[0], mode, 0666);
937 /* this could get lost if stderr has been redirected, but
938 bash and ash both lose it as well (though zsh doesn't!) */
939 fprintf(stderr,"error opening %s: %s\n", redir->word.gl_pathv[0],
947 if (openfd != redir->fd) {
948 if (squirrel && redir->fd < 3) {
949 squirrel[redir->fd] = dup(redir->fd);
954 dup2(openfd, redir->fd);
962 static void restore_redirects(int squirrel[])
965 for (i=0; i<3; i++) {
968 /* No error checking. I sure wouldn't know what
969 * to do with an error if I found one! */
976 /* XXX this definitely needs some more thought, work, and
977 * cribbing from other shells */
978 static int pipe_wait(struct pipe *pi)
980 int rcode=0, i, pid, running, status;
981 running = pi->num_progs;
983 pid=waitpid(-1, &status, 0);
984 if (pid < 0) perror_msg_and_die("waitpid");
985 for (i=0; i < pi->num_progs; i++) {
986 if (pi->progs[i].pid == pid) {
987 if (i==pi->num_progs-1) rcode=WEXITSTATUS(status);
988 pi->progs[i].pid = 0;
997 /* very simple version for testing */
998 static void pseudo_exec(struct child_prog *child)
1001 struct built_in_command *x;
1004 * Check if the command matches any of the builtins.
1005 * Depending on context, this might be redundant. But it's
1006 * easier to waste a few CPU cycles than it is to figure out
1007 * if this is one of those cases.
1009 for (x = bltins; x->cmd; x++) {
1010 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1011 debug_printf("builtin exec %s\n", child->argv[0]);
1012 exit(x->function(child));
1016 /* Check if the command matches any busybox internal commands
1018 * FIXME: This feature is not 100% safe, since
1019 * BusyBox is not fully reentrant, so we have no guarantee the things
1020 * from the .bss are still zeroed, or that things from .data are still
1021 * at their defaults. We could exec ourself from /proc/self/exe, but I
1022 * really dislike relying on /proc for things. We could exec ourself
1023 * from global_argv[0], but if we are in a chroot, we may not be able
1024 * to find ourself... */
1025 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1028 char** argv_l=child->argv;
1029 char *name = child->argv[0];
1031 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1032 /* Following discussions from November 2000 on the busybox mailing
1033 * list, the default configuration, (without
1034 * get_last_path_component()) lets the user force use of an
1035 * external command by specifying the full (with slashes) filename.
1036 * If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then applets
1037 * _aways_ override external commands, so if you want to run
1038 * /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
1039 * filesystem and is _not_ busybox. Some systems may want this,
1041 name = get_last_path_component(name);
1043 /* Count argc for use in a second... */
1044 for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1046 debug_printf("running applet %s\n", name);
1047 run_applet_by_name(name, argc_l, child->argv);
1050 debug_printf("exec of %s\n",child->argv[0]);
1051 execvp(child->argv[0],child->argv);
1054 } else if (child->group) {
1055 debug_printf("runtime nesting to group\n");
1056 interactive=0; /* crucial!!!! */
1057 rcode = run_list_real(child->group);
1058 /* OK to leak memory by not calling run_list_test,
1059 * since this process is about to exit */
1062 /* Can happen. See what bash does with ">foo" by itself. */
1063 debug_printf("trying to pseudo_exec null command\n");
1068 static void insert_bg_job(struct pipe *pi)
1070 struct pipe *thejob;
1072 /* Linear search for the ID of the job to use */
1074 for (thejob = job_list->head; thejob; thejob = thejob->next)
1075 if (thejob->jobid >= pi->jobid)
1076 pi->jobid = thejob->jobid + 1;
1078 /* add thejob to the list of running jobs */
1079 if (!job_list->head) {
1080 thejob = job_list->head = xmalloc(sizeof(*thejob));
1082 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1083 thejob->next = xmalloc(sizeof(*thejob));
1084 thejob = thejob->next;
1087 /* physically copy the struct job */
1088 memcpy(thejob, pi, sizeof(struct pipe));
1089 thejob->next = NULL;
1090 thejob->running_progs = thejob->num_progs;
1091 thejob->stopped_progs = 0;
1092 thejob->text = xmalloc(MAX_LINE);
1094 //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1096 char *bar=thejob->text;
1097 char **foo=pi->progs[0].argv;
1098 while(foo && *foo) {
1099 bar += sprintf(bar, "%s ", *foo++);
1103 /* we don't wait for background thejobs to return -- append it
1104 to the list of backgrounded thejobs and leave it alone */
1105 printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1106 last_bg_pid = thejob->progs[0].pid;
1109 /* remove a backgrounded job from a jobset */
1110 static void remove_bg_job(struct pipe *pi)
1112 struct pipe *prev_pipe;
1115 if (pi == job_list->head) {
1116 job_list->head = pi->next;
1118 prev_pipe = job_list->head;
1119 while (prev_pipe->next != pi)
1120 prev_pipe = prev_pipe->next;
1121 prev_pipe->next = pi->next;
1127 /* free up all memory from a pipe */
1128 static void free_pipe(struct pipe *pi)
1132 for (i = 0; i < pi->num_progs; i++) {
1133 free(pi->progs[i].argv);
1134 if (pi->progs[i].redirects)
1135 free(pi->progs[i].redirects);
1143 memset(pi, 0, sizeof(struct pipe));
1147 /* Checks to see if any background processes have exited -- if they
1148 have, figure out why and see if a job has completed */
1149 static void checkjobs()
1156 while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
1157 for (pi = job_list->head; pi; pi = pi->next) {
1159 while (prognum < pi->num_progs &&
1160 pi->progs[prognum].pid != childpid) prognum++;
1161 if (prognum < pi->num_progs)
1165 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1167 pi->running_progs--;
1168 pi->progs[prognum].pid = 0;
1170 if (!pi->running_progs) {
1171 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1178 pi->stopped_progs++;
1179 pi->progs[prognum].is_stopped = 1;
1181 if (pi->stopped_progs == pi->num_progs) {
1182 printf(JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
1187 if (childpid == -1 && errno != ECHILD)
1188 perror_msg("waitpid");
1190 /* move the shell to the foreground */
1191 if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
1192 perror_msg("tcsetpgrp");
1195 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1196 * to finish. See pipe_wait().
1198 * return code is normally -1, when the caller has to wait for children
1199 * to finish to determine the exit status of the pipe. If the pipe
1200 * is a simple builtin command, however, the action is done by the
1201 * time run_pipe_real returns, and the exit code is provided as the
1204 * The input of the pipe is always stdin, the output is always
1205 * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1206 * because it tries to avoid running the command substitution in
1207 * subshell, when that is in fact necessary. The subshell process
1208 * now has its stdout directed to the input of the appropriate pipe,
1209 * so this routine is noticeably simpler.
1211 static int run_pipe_real(struct pipe *pi)
1215 int nextin, nextout;
1216 int pipefds[2]; /* pipefds[0] is for reading */
1217 struct child_prog *child;
1218 struct built_in_command *x;
1224 /* Check if we are supposed to run in the foreground */
1225 if (interactive && pi->followup!=PIPE_BG) {
1226 if ((pi->pgrp = tcgetpgrp(ctty = 2)) < 0
1227 && (pi->pgrp = tcgetpgrp(ctty = 0)) < 0
1228 && (pi->pgrp = tcgetpgrp(ctty = 1)) < 0)
1229 return errno = ENOTTY, -1;
1231 if (pi->pgrp < 0 && pi->pgrp != getpgrp())
1232 return errno = EPERM, -1;
1235 /* Check if this is a simple builtin (not part of a pipe).
1236 * Builtins within pipes have to fork anyway, and are handled in
1237 * pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
1239 if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1240 child = & (pi->progs[0]);
1241 if (child->group && ! child->subshell) {
1242 int squirrel[] = {-1, -1, -1};
1244 debug_printf("non-subshell grouping\n");
1245 setup_redirects(child, squirrel);
1246 /* XXX could we merge code with following builtin case,
1247 * by creating a pseudo builtin that calls run_list_real? */
1248 rcode = run_list_real(child->group);
1249 restore_redirects(squirrel);
1252 for (x = bltins; x->cmd; x++) {
1253 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1254 int squirrel[] = {-1, -1, -1};
1256 if (x->function == builtin_exec && child->argv[1]==NULL) {
1257 debug_printf("magic exec\n");
1258 setup_redirects(child,NULL);
1259 return EXIT_SUCCESS;
1261 debug_printf("builtin inline %s\n", child->argv[0]);
1262 /* XXX setup_redirects acts on file descriptors, not FILEs.
1263 * This is perfect for work that comes after exec().
1264 * Is it really safe for inline use? Experimentally,
1265 * things seem to work with glibc. */
1266 setup_redirects(child, squirrel);
1267 rcode = x->function(child);
1268 restore_redirects(squirrel);
1274 for (i = 0; i < pi->num_progs; i++) {
1275 child = & (pi->progs[i]);
1277 /* pipes are inserted between pairs of commands */
1278 if ((i + 1) < pi->num_progs) {
1279 if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1280 nextout = pipefds[1];
1286 /* XXX test for failed fork()? */
1287 if (!(child->pid = fork())) {
1289 signal(SIGTTOU, SIG_DFL);
1301 if (pipefds[0]!=-1) {
1302 close(pipefds[0]); /* opposite end of our output pipe */
1305 /* Like bash, explicit redirects override pipes,
1306 * and the pipe fd is available for dup'ing. */
1307 setup_redirects(child,NULL);
1309 if (pi->followup!=PIPE_BG) {
1310 /* Put our child in the process group whose leader is the
1311 * first process in this pipe. */
1313 pi->pgrp = child->pid;
1315 /* Don't check for errors. The child may be dead already,
1316 * in which case setpgid returns error code EACCES. */
1317 if (setpgid(0, pi->pgrp) == 0) {
1318 signal(SIGTTOU, SIG_IGN);
1319 tcsetpgrp(ctty, pi->pgrp);
1320 signal(SIGTTOU, SIG_DFL);
1326 /* Put our child in the process group whose leader is the
1327 * first process in this pipe. */
1329 pi->pgrp = child->pid;
1331 /* Don't check for errors. The child may be dead already,
1332 * in which case setpgid returns error code EACCES. */
1333 setpgid(child->pid, pi->pgrp);
1340 /* If there isn't another process, nextin is garbage
1341 but it doesn't matter */
1342 nextin = pipefds[0];
1347 static int run_list_real(struct pipe *pi)
1350 int if_code=0, next_if_code=0; /* need double-buffer to handle elif */
1351 reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1352 for (;pi;pi=pi->next) {
1354 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);
1355 if (rmode == skip_more_in_this_rmode) continue;
1356 skip_more_in_this_rmode = RES_XXXX;
1357 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1358 if (rmode == RES_THEN && if_code) continue;
1359 if (rmode == RES_ELSE && !if_code) continue;
1360 if (rmode == RES_ELIF && !if_code) continue;
1361 if (pi->num_progs == 0) continue;
1362 rcode = run_pipe_real(pi);
1364 /* We only ran a builtin: rcode was set by the return value
1365 * of run_pipe_real(), and we don't need to wait for anything. */
1366 } else if (pi->followup==PIPE_BG) {
1367 /* XXX check bash's behavior with nontrivial pipes */
1368 /* XXX compute jobid */
1369 /* XXX what does bash do with attempts to background builtins? */
1371 rcode = EXIT_SUCCESS;
1375 /* move the new process group into the foreground */
1376 /* suppress messages when run from /linuxrc mag@sysgo.de */
1377 //signal(SIGTTIN, SIG_IGN);
1378 //signal(SIGTTOU, SIG_IGN);
1379 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
1380 perror_msg("tcsetpgrp");
1381 rcode = pipe_wait(pi);
1382 if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
1383 perror_msg("tcsetpgrp");
1384 //signal(SIGTTIN, SIG_DFL);
1385 //signal(SIGTTOU, SIG_DFL);
1387 rcode = pipe_wait(pi);
1390 last_return_code=rcode;
1391 if ( rmode == RES_IF || rmode == RES_ELIF )
1392 next_if_code=rcode; /* can be overwritten a number of times */
1393 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1394 (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1395 skip_more_in_this_rmode=rmode;
1396 /* return rcode; */ /* XXX broken if list is part of if/then/else */
1402 /* broken, of course, but OK for testing */
1403 static char *indenter(int i)
1405 static char blanks[]=" ";
1406 return &blanks[sizeof(blanks)-i-1];
1409 /* return code is the exit status of the pipe */
1410 static int run_pipe_test(struct pipe *pi, int indent)
1413 struct child_prog *child;
1414 struct redir_struct *r, *rnext;
1415 int a, i, ret_code=0;
1416 char *ind = indenter(indent);
1417 final_printf("%s run pipe: (pid %d)\n",ind,getpid());
1418 for (i=0; i<pi->num_progs; i++) {
1419 child = &pi->progs[i];
1420 final_printf("%s command %d:\n",ind,i);
1422 for (a=0,p=child->argv; *p; a++,p++) {
1423 final_printf("%s argv[%d] = %s\n",ind,a,*p);
1425 globfree(&child->glob_result);
1427 } else if (child->group) {
1428 final_printf("%s begin group (subshell:%d)\n",ind, child->subshell);
1429 ret_code = run_list_test(child->group,indent+3);
1430 final_printf("%s end group\n",ind);
1432 final_printf("%s (nil)\n",ind);
1434 for (r=child->redirects; r; r=rnext) {
1435 final_printf("%s redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
1437 final_printf(" %s\n", *r->word.gl_pathv);
1440 final_printf("&%d\n", r->dup);
1445 child->redirects=NULL;
1447 free(pi->progs); /* children are an array, they get freed all at once */
1452 static int run_list_test(struct pipe *head, int indent)
1454 int rcode=0; /* if list has no members */
1455 struct pipe *pi, *next;
1456 char *ind = indenter(indent);
1457 for (pi=head; pi; pi=next) {
1458 if (pi->num_progs == 0) break;
1459 final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
1460 rcode = run_pipe_test(pi, indent);
1461 final_printf("%s pipe followup code %d\n", ind, pi->followup);
1469 /* Select which version we will use */
1470 static int run_list(struct pipe *pi)
1474 rcode = run_list_real(pi);
1476 /* run_list_test has the side effect of clearing memory
1477 * In the long run that function can be merged with run_list_real,
1478 * but doing that now would hobble the debugging effort. */
1479 run_list_test(pi,0);
1483 /* The API for glob is arguably broken. This routine pushes a non-matching
1484 * string into the output structure, removing non-backslashed backslashes.
1485 * If someone can prove me wrong, by performing this function within the
1486 * original glob(3) api, feel free to rewrite this routine into oblivion.
1487 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1488 * XXX broken if the last character is '\\', check that before calling.
1490 static int globhack(const char *src, int flags, glob_t *pglob)
1495 for (cnt=1, s=src; *s; s++) {
1496 if (*s == '\\') s++;
1500 if (!dest) return GLOB_NOSPACE;
1501 if (!(flags & GLOB_APPEND)) {
1502 pglob->gl_pathv=NULL;
1507 pathc = ++pglob->gl_pathc;
1508 pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1509 if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1510 pglob->gl_pathv[pathc-1]=dest;
1511 pglob->gl_pathv[pathc]=NULL;
1512 for (s=src; *s; s++, dest++) {
1513 if (*s == '\\') s++;
1520 /* XXX broken if the last character is '\\', check that before calling */
1521 static int glob_needed(const char *s)
1524 if (*s == '\\') s++;
1525 if (strchr("*[?",*s)) return 1;
1531 static void globprint(glob_t *pglob)
1534 debug_printf("glob_t at %p:\n", pglob);
1535 debug_printf(" gl_pathc=%d gl_pathv=%p gl_offs=%d gl_flags=%d\n",
1536 pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
1537 for (i=0; i<pglob->gl_pathc; i++)
1538 debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
1539 pglob->gl_pathv[i], pglob->gl_pathv[i]);
1543 static int xglob(o_string *dest, int flags, glob_t *pglob)
1547 /* short-circuit for null word */
1548 /* we can code this better when the debug_printf's are gone */
1549 if (dest->length == 0) {
1550 if (dest->nonnull) {
1551 /* bash man page calls this an "explicit" null */
1552 gr = globhack(dest->data, flags, pglob);
1553 debug_printf("globhack returned %d\n",gr);
1557 } else if (glob_needed(dest->data)) {
1558 gr = glob(dest->data, flags, NULL, pglob);
1559 debug_printf("glob returned %d\n",gr);
1560 if (gr == GLOB_NOMATCH) {
1561 /* quote removal, or more accurately, backslash removal */
1562 gr = globhack(dest->data, flags, pglob);
1563 debug_printf("globhack returned %d\n",gr);
1566 gr = globhack(dest->data, flags, pglob);
1567 debug_printf("globhack returned %d\n",gr);
1569 if (gr == GLOB_NOSPACE) {
1570 fprintf(stderr,"out of memory during glob\n");
1573 if (gr != 0) { /* GLOB_ABORTED ? */
1574 fprintf(stderr,"glob(3) error %d\n",gr);
1576 /* globprint(glob_target); */
1580 /* the src parameter allows us to peek forward to a possible &n syntax
1581 * for file descriptor duplication, e.g., "2>&1".
1582 * Return code is 0 normally, 1 if a syntax error is detected in src.
1583 * Resource errors (in xmalloc) cause the process to exit */
1584 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1585 struct in_str *input)
1587 struct child_prog *child=ctx->child;
1588 struct redir_struct *redir = child->redirects;
1589 struct redir_struct *last_redir=NULL;
1591 /* Create a new redir_struct and drop it onto the end of the linked list */
1596 redir = xmalloc(sizeof(struct redir_struct));
1599 last_redir->next=redir;
1601 child->redirects=redir;
1605 redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1607 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1609 /* Check for a '2>&1' type redirect */
1610 redir->dup = redirect_dup_num(input);
1611 if (redir->dup == -2) return 1; /* syntax error */
1612 if (redir->dup != -1) {
1613 /* Erik had a check here that the file descriptor in question
1614 * is legit; I postpone that to "run time"
1615 * A "-" representation of "close me" shows up as a -3 here */
1616 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1618 /* We do _not_ try to open the file that src points to,
1619 * since we need to return and let src be expanded first.
1620 * Set ctx->pending_redirect, so we know what to do at the
1621 * end of the next parsed word.
1623 ctx->pending_redirect = redir;
1628 struct pipe *new_pipe(void) {
1630 pi = xmalloc(sizeof(struct pipe));
1634 pi->followup = 0; /* invalid */
1638 static void initialize_context(struct p_context *ctx)
1641 ctx->pending_redirect=NULL;
1643 ctx->list_head=new_pipe();
1644 ctx->pipe=ctx->list_head;
1647 done_command(ctx); /* creates the memory for working child */
1650 /* normal return is 0
1651 * if a reserved word is found, and processed, return 1
1652 * should handle if, then, elif, else, fi, for, while, until, do, done.
1653 * case, function, and select are obnoxious, save those for later.
1655 int reserved_word(o_string *dest, struct p_context *ctx)
1657 struct reserved_combo {
1662 /* Mostly a list of accepted follow-up reserved words.
1663 * FLAG_END means we are done with the sequence, and are ready
1664 * to turn the compound list into a command.
1665 * FLAG_START means the word must start a new compound list.
1667 static struct reserved_combo reserved_list[] = {
1668 { "if", RES_IF, FLAG_THEN | FLAG_START },
1669 { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
1670 { "elif", RES_ELIF, FLAG_THEN },
1671 { "else", RES_ELSE, FLAG_FI },
1672 { "fi", RES_FI, FLAG_END },
1673 { "for", RES_FOR, FLAG_DO | FLAG_START },
1674 { "while", RES_WHILE, FLAG_DO | FLAG_START },
1675 { "until", RES_UNTIL, FLAG_DO | FLAG_START },
1676 { "do", RES_DO, FLAG_DONE },
1677 { "done", RES_DONE, FLAG_END }
1679 struct reserved_combo *r;
1680 for (r=reserved_list;
1681 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
1682 r<reserved_list+NRES; r++) {
1683 if (strcmp(dest->data, r->literal) == 0) {
1684 debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
1685 if (r->flag & FLAG_START) {
1686 struct p_context *new = xmalloc(sizeof(struct p_context));
1687 debug_printf("push stack\n");
1688 *new = *ctx; /* physical copy */
1689 initialize_context(ctx);
1691 } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
1698 ctx->old_flag = r->flag;
1699 if (ctx->old_flag & FLAG_END) {
1700 struct p_context *old;
1701 debug_printf("pop stack\n");
1703 old->child->group = ctx->list_head;
1704 *ctx = *old; /* physical copy */
1714 /* normal return is 0.
1715 * Syntax or xglob errors return 1. */
1716 static int done_word(o_string *dest, struct p_context *ctx)
1718 struct child_prog *child=ctx->child;
1719 glob_t *glob_target;
1722 debug_printf("done_word: %s %p\n", dest->data, child);
1723 if (dest->length == 0 && !dest->nonnull) {
1724 debug_printf(" true null, ignored\n");
1727 if (ctx->pending_redirect) {
1728 glob_target = &ctx->pending_redirect->word;
1732 return 1; /* syntax error, groups and arglists don't mix */
1735 debug_printf("checking %s for reserved-ness\n",dest->data);
1736 if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
1738 glob_target = &child->glob_result;
1739 if (child->argv) flags |= GLOB_APPEND;
1741 gr = xglob(dest, flags, glob_target);
1742 if (gr != 0) return 1;
1745 if (ctx->pending_redirect) {
1746 ctx->pending_redirect=NULL;
1747 if (glob_target->gl_pathc != 1) {
1748 fprintf(stderr, "ambiguous redirect\n");
1752 child->argv = glob_target->gl_pathv;
1757 /* The only possible error here is out of memory, in which case
1759 static int done_command(struct p_context *ctx)
1761 /* The child is really already in the pipe structure, so
1762 * advance the pipe counter and make a new, null child.
1763 * Only real trickiness here is that the uncommitted
1764 * child structure, to which ctx->child points, is not
1765 * counted in pi->num_progs. */
1766 struct pipe *pi=ctx->pipe;
1767 struct child_prog *prog=ctx->child;
1769 if (prog && prog->group == NULL
1770 && prog->argv == NULL
1771 && prog->redirects == NULL) {
1772 debug_printf("done_command: skipping null command\n");
1776 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
1778 debug_printf("done_command: initializing\n");
1780 pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
1782 prog = pi->progs + pi->num_progs;
1783 prog->redirects = NULL;
1785 prog->is_stopped = 0;
1787 prog->glob_result.gl_pathv = NULL;
1791 /* but ctx->pipe and ctx->list_head remain unchanged */
1795 static int done_pipe(struct p_context *ctx, pipe_style type)
1798 done_command(ctx); /* implicit closure of previous command */
1799 debug_printf("done_pipe, type %d\n", type);
1800 ctx->pipe->followup = type;
1801 ctx->pipe->r_mode = ctx->w;
1803 ctx->pipe->next = new_p;
1806 done_command(ctx); /* set up new pipe to accept commands */
1810 /* peek ahead in the in_str to find out if we have a "&n" construct,
1811 * as in "2>&1", that represents duplicating a file descriptor.
1812 * returns either -2 (syntax error), -1 (no &), or the number found.
1814 static int redirect_dup_num(struct in_str *input)
1818 if (ch != '&') return -1;
1820 b_getch(input); /* get the & */
1824 return -3; /* "-" represents "close me" */
1826 while (isdigit(ch)) {
1834 fprintf(stderr, "ambiguous redirect\n");
1838 /* If a redirect is immediately preceded by a number, that number is
1839 * supposed to tell which file descriptor to redirect. This routine
1840 * looks for such preceding numbers. In an ideal world this routine
1841 * needs to handle all the following classes of redirects...
1842 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
1843 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
1844 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
1845 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
1846 * A -1 output from this program means no valid number was found, so the
1847 * caller should use the appropriate default for this redirection.
1849 static int redirect_opt_num(o_string *o)
1853 if (o->length==0) return -1;
1854 for(num=0; num<o->length; num++) {
1855 if (!isdigit(*(o->data+num))) {
1859 /* reuse num (and save an int) */
1865 FILE *generate_stream_from_list(struct pipe *head)
1869 int pid, channel[2];
1870 if (pipe(channel)<0) perror_msg_and_die("pipe");
1873 perror_msg_and_die("fork");
1874 } else if (pid==0) {
1876 if (channel[1] != 1) {
1881 #define SURROGATE "surrogate response"
1882 write(1,SURROGATE,sizeof(SURROGATE));
1883 exit(run_list(head));
1885 exit(run_list_real(head)); /* leaks memory */
1888 debug_printf("forked child %d\n",pid);
1890 pf = fdopen(channel[0],"r");
1891 debug_printf("pipe on FILE *%p\n",pf);
1893 run_list_test(head,0);
1894 pf=popen("echo surrogate response","r");
1895 debug_printf("started fake pipe on FILE *%p\n",pf);
1900 /* this version hacked for testing purposes */
1901 /* return code is exit status of the process that is run. */
1902 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
1905 o_string result=NULL_O_STRING;
1906 struct p_context inner;
1908 struct in_str pipe_str;
1909 initialize_context(&inner);
1911 /* recursion to generate command */
1912 retcode = parse_stream(&result, &inner, input, subst_end);
1913 if (retcode != 0) return retcode; /* syntax error or EOF */
1914 done_word(&result, &inner);
1915 done_pipe(&inner, PIPE_SEQ);
1918 p=generate_stream_from_list(inner.list_head);
1919 if (p==NULL) return 1;
1920 mark_open(fileno(p));
1921 setup_file_in_str(&pipe_str, p);
1923 /* now send results of command back into original context */
1924 retcode = parse_stream(dest, ctx, &pipe_str, '\0');
1925 /* XXX In case of a syntax error, should we try to kill the child?
1926 * That would be tough to do right, so just read until EOF. */
1928 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
1931 debug_printf("done reading from pipe, pclose()ing\n");
1932 /* This is the step that wait()s for the child. Should be pretty
1933 * safe, since we just read an EOF from its stdout. We could try
1934 * to better, by using wait(), and keeping track of background jobs
1935 * at the same time. That would be a lot of work, and contrary
1936 * to the KISS philosophy of this program. */
1937 mark_closed(fileno(p));
1939 debug_printf("pclosed, retcode=%d\n",retcode);
1940 /* XXX this process fails to trim a single trailing newline */
1944 static int parse_group(o_string *dest, struct p_context *ctx,
1945 struct in_str *input, int ch)
1948 struct p_context sub;
1949 struct child_prog *child = ctx->child;
1952 return 1; /* syntax error, groups and arglists don't mix */
1954 initialize_context(&sub);
1956 case '(': endch=')'; child->subshell=1; break;
1957 case '{': endch='}'; break;
1958 default: syntax(); /* really logic error */
1960 rcode=parse_stream(dest,&sub,input,endch);
1961 done_word(dest,&sub); /* finish off the final word in the subcontext */
1962 done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
1963 child->group = sub.list_head;
1965 /* child remains "open", available for possible redirects */
1968 /* basically useful version until someone wants to get fancier,
1969 * see the bash man page under "Parameter Expansion" */
1970 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src)
1973 if (src->data) p = getenv(src->data);
1974 if (p) parse_string(dest, ctx, p); /* recursion */
1978 /* return code: 0 for OK, 1 for syntax error */
1979 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
1982 o_string alt=NULL_O_STRING;
1984 int ch = input->peek(input); /* first character after the $ */
1985 debug_printf("handle_dollar: ch=%c\n",ch);
1987 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
1991 lookup_param(dest, ctx, &alt);
1992 } else if (isdigit(ch)) {
1993 i = ch-'0'; /* XXX is $0 special? */
1994 if (i<global_argc) {
1995 parse_string(dest, ctx, global_argv[i]); /* recursion */
1998 } else switch (ch) {
2000 b_adduint(dest,getpid());
2004 if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2008 b_adduint(dest,last_return_code);
2012 b_adduint(dest,global_argc ? global_argc-1 : 0);
2017 /* XXX maybe someone will try to escape the '}' */
2018 while(ch=b_getch(input),ch!=EOF && ch!='}') {
2025 lookup_param(dest, ctx, &alt);
2029 process_command_subs(dest, ctx, input, ')');
2033 for (i=1; i<global_argc; i++) {
2034 parse_string(dest, ctx, global_argv[i]);
2035 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2041 /* still unhandled, but should be eventually */
2042 fprintf(stderr,"unhandled syntax: $%c\n",ch);
2046 b_addqchr(dest,'$',dest->quote);
2048 /* Eat the character if the flag was set. If the compiler
2049 * is smart enough, we could substitute "b_getch(input);"
2050 * for all the "advance = 1;" above, and also end up with
2051 * a nice size-optimized program. Hah! That'll be the day.
2053 if (advance) b_getch(input);
2057 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2060 setup_string_in_str(&foo, src);
2061 return parse_stream(dest, ctx, &foo, '\0');
2064 /* return code is 0 for normal exit, 1 for syntax error */
2065 int parse_stream(o_string *dest, struct p_context *ctx,
2066 struct in_str *input, int end_trigger)
2070 redir_type redir_style;
2073 /* Only double-quote state is handled in the state variable dest->quote.
2074 * A single-quote triggers a bypass of the main loop until its mate is
2075 * found. When recursing, quote state is passed in via dest->quote. */
2077 debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2078 while ((ch=b_getch(input))!=EOF) {
2080 next = (ch == '\n') ? 0 : b_peek(input);
2081 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2082 ch,ch,m,dest->quote);
2083 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2084 b_addqchr(dest, ch, dest->quote);
2086 if (m==2) { /* unquoted IFS */
2087 done_word(dest, ctx);
2088 /* If we aren't performing a substitution, treat a newline as a
2089 * command separator. */
2090 if (end_trigger != '\0' && ch=='\n')
2091 done_pipe(ctx,PIPE_SEQ);
2093 if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2094 debug_printf("leaving parse_stream\n");
2099 /* Yahoo! Time to run with it! */
2100 done_pipe(ctx,PIPE_SEQ);
2101 run_list(ctx->list_head);
2102 initialize_context(ctx);
2105 if (m!=2) switch (ch) {
2107 if (dest->length == 0 && !dest->quote) {
2108 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2110 b_addqchr(dest, ch, dest->quote);
2118 b_addqchr(dest, '\\', dest->quote);
2119 b_addqchr(dest, b_getch(input), dest->quote);
2122 if (handle_dollar(dest, ctx, input)!=0) return 1;
2126 while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2136 dest->quote = !dest->quote;
2139 process_command_subs(dest, ctx, input, '`');
2142 redir_fd = redirect_opt_num(dest);
2143 done_word(dest, ctx);
2144 redir_style=REDIRECT_OVERWRITE;
2146 redir_style=REDIRECT_APPEND;
2148 } else if (next == '(') {
2149 syntax(); /* until we support >(list) Process Substitution */
2152 setup_redirect(ctx, redir_fd, redir_style, input);
2155 redir_fd = redirect_opt_num(dest);
2156 done_word(dest, ctx);
2157 redir_style=REDIRECT_INPUT;
2159 redir_style=REDIRECT_HEREIS;
2161 } else if (next == '>') {
2162 redir_style=REDIRECT_IO;
2164 } else if (next == '(') {
2165 syntax(); /* until we support <(list) Process Substitution */
2168 setup_redirect(ctx, redir_fd, redir_style, input);
2171 done_word(dest, ctx);
2172 done_pipe(ctx,PIPE_SEQ);
2175 done_word(dest, ctx);
2178 done_pipe(ctx,PIPE_AND);
2180 done_pipe(ctx,PIPE_BG);
2184 done_word(dest, ctx);
2187 done_pipe(ctx,PIPE_OR);
2189 /* we could pick up a file descriptor choice here
2190 * with redirect_opt_num(), but bash doesn't do it.
2191 * "echo foo 2| cat" yields "foo 2". */
2197 if (parse_group(dest, ctx, input, ch)!=0) return 1;
2201 syntax(); /* Proper use of this character caught by end_trigger */
2205 syntax(); /* this is really an internal logic error */
2210 /* complain if quote? No, maybe we just finished a command substitution
2211 * that was quoted. Example:
2212 * $ echo "`cat foo` plus more"
2213 * and we just got the EOF generated by the subshell that ran "cat foo"
2214 * The only real complaint is if we got an EOF when end_trigger != '\0',
2215 * that is, we were really supposed to get end_trigger, and never got
2216 * one before the EOF. Can't use the standard "syntax error" return code,
2217 * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2218 if (end_trigger != '\0') return -1;
2222 void mapset(const unsigned char *set, int code)
2224 const unsigned char *s;
2225 for (s=set; *s; s++) map[*s] = code;
2228 void update_ifs_map(void)
2230 /* char *ifs and char map[256] are both globals. */
2231 ifs = getenv("IFS");
2232 if (ifs == NULL) ifs=" \t\n";
2233 /* Precompute a list of 'flow through' behavior so it can be treated
2234 * quickly up front. Computation is necessary because of IFS.
2235 * Special case handling of IFS == " \t\n" is not implemented.
2236 * The map[] array only really needs two bits each, and on most machines
2237 * that would be faster because of the reduced L1 cache footprint.
2239 memset(map,0,256); /* most characters flow through always */
2240 mapset("\\$'\"`", 3); /* never flow through */
2241 mapset("<>;&|(){}#", 1); /* flow through if quoted */
2242 mapset(ifs, 2); /* also flow through if quoted */
2245 /* most recursion does not come through here, the exeception is
2246 * from builtin_source() */
2247 int parse_stream_outer(struct in_str *inp)
2250 struct p_context ctx;
2251 o_string temp=NULL_O_STRING;
2254 initialize_context(&ctx);
2257 rcode = parse_stream(&temp, &ctx, inp, '\n');
2258 done_word(&temp, &ctx);
2259 done_pipe(&ctx,PIPE_SEQ);
2260 run_list(ctx.list_head);
2261 } while (rcode != -1); /* loop on syntax errors, return on EOF */
2265 static int parse_string_outer(const char *s)
2267 struct in_str input;
2268 setup_string_in_str(&input, s);
2269 return parse_stream_outer(&input);
2272 static int parse_file_outer(FILE *f)
2275 struct in_str input;
2276 setup_file_in_str(&input, f);
2277 rcode = parse_stream_outer(&input);
2281 int shell_main(int argc, char **argv)
2285 struct jobset joblist_end = { NULL, NULL };
2286 job_list = &joblist_end;
2288 last_return_code=EXIT_SUCCESS;
2290 /* XXX what should these be while sourcing /etc/profile? */
2294 /* don't pay any attention to this signal; it just confuses
2295 things and isn't really meant for shells anyway */
2296 signal(SIGTTOU, SIG_IGN);
2298 if (argv[0] && argv[0][0] == '-') {
2299 debug_printf("\nsourcing /etc/profile\n");
2300 input = xfopen("/etc/profile", "r");
2301 mark_open(fileno(input));
2302 parse_file_outer(input);
2303 mark_closed(fileno(input));
2308 /* initialize the cwd -- this is never freed...*/
2310 #ifdef BB_FEATURE_COMMAND_EDITING
2311 cmdedit_set_initial_prompt();
2316 while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2320 global_argv = argv+optind;
2321 global_argc = argc-optind;
2322 opt = parse_string_outer(optarg);
2333 fprintf(stderr, "Usage: sh [FILE]...\n"
2334 " or: sh -c command [args]...\n\n");
2338 /* A shell is interactive if the `-i' flag was given, or if all of
2339 * the following conditions are met:
2341 * no arguments remaining or the -s flag given
2342 * standard input is a terminal
2343 * standard output is a terminal
2344 * Refer to Posix.2, the description of the `sh' utility. */
2345 if (argv[optind]==NULL && input==stdin &&
2346 isatty(fileno(stdin)) && isatty(fileno(stdout))) {
2350 debug_printf("\ninteractive=%d\n", interactive);
2352 /* Looks like they want an interactive shell */
2353 fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n");
2354 opt=parse_file_outer(stdin);
2358 debug_printf("\nrunning script '%s'\n", argv[optind]);
2359 global_argv = argv+optind;
2360 global_argc = argc-optind;
2361 input = xfopen(argv[optind], "r");
2362 opt = parse_file_outer(input);
2364 #ifdef BB_FEATURE_CLEAN_UP
2369 return(opt?opt:last_return_code);