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 * finish implementing local variable assignment
59 * change { and } from special chars to reserved words
60 * builtins: break, continue, eval, return, set, trap, ulimit
62 * handle children going into background
63 * clean up recognition of null pipes
64 * check setting of global_argc and global_argv
65 * control-C handling, probably with longjmp
66 * follow IFS rules more precisely, including update semantics
67 * figure out what to do with backslash-newline
68 * explain why we use signal instead of sigaction
69 * propagate syntax errors, die on resource errors?
70 * continuation lines, both explicit and implicit - done?
71 * memory leak finding and plugging - done?
72 * more testing, especially quoting rules and redirection
73 * document how quoting rules not precisely followed for variable assignments
74 * maybe change map[] to use 2-bit entries
75 * (eventually) remove all the printf's
77 * This program is free software; you can redistribute it and/or modify
78 * it under the terms of the GNU General Public License as published by
79 * the Free Software Foundation; either version 2 of the License, or
80 * (at your option) any later version.
82 * This program is distributed in the hope that it will be useful,
83 * but WITHOUT ANY WARRANTY; without even the implied warranty of
84 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
85 * General Public License for more details.
87 * You should have received a copy of the GNU General Public License
88 * along with this program; if not, write to the Free Software
89 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
91 #include <ctype.h> /* isalpha, isdigit */
92 #include <unistd.h> /* getpid */
93 #include <stdlib.h> /* getenv, atoi */
94 #include <string.h> /* strchr */
95 #include <stdio.h> /* popen etc. */
96 #include <glob.h> /* glob, of course */
97 #include <stdarg.h> /* va_list */
100 #include <getopt.h> /* should be pretty obvious */
102 #include <sys/stat.h> /* ulimit */
103 #include <sys/types.h>
104 #include <sys/wait.h>
107 /* #include <dmalloc.h> */
108 /* #define DEBUG_SHELL */
114 #define applet_name "hush"
115 #include "standalone.h"
116 #define shell_main main
117 #define BB_FEATURE_SH_SIMPLE_PROMPT
122 REDIRECT_OVERWRITE = 2,
128 /* The descrip member of this structure is only used to make debugging
130 struct {int mode; int default_fd; char *descrip;} redir_table[] = {
132 { O_RDONLY, 0, "<" },
133 { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
134 { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
135 { O_RDONLY, -1, "<<" },
146 /* might eventually control execution */
162 #define FLAG_END (1<<RES_NONE)
163 #define FLAG_IF (1<<RES_IF)
164 #define FLAG_THEN (1<<RES_THEN)
165 #define FLAG_ELIF (1<<RES_ELIF)
166 #define FLAG_ELSE (1<<RES_ELSE)
167 #define FLAG_FI (1<<RES_FI)
168 #define FLAG_FOR (1<<RES_FOR)
169 #define FLAG_WHILE (1<<RES_WHILE)
170 #define FLAG_UNTIL (1<<RES_UNTIL)
171 #define FLAG_DO (1<<RES_DO)
172 #define FLAG_DONE (1<<RES_DONE)
173 #define FLAG_START (1<<RES_XXXX)
175 /* This holds pointers to the various results of parsing */
177 struct child_prog *child;
178 struct pipe *list_head;
180 struct redir_struct *pending_redirect;
182 int old_flag; /* for figuring out valid reserved words */
183 struct p_context *stack;
184 /* How about quoting status? */
187 struct redir_struct {
188 redir_type type; /* type of redirection */
189 int fd; /* file descriptor being redirected */
190 int dup; /* -1, or file descriptor being duplicated */
191 struct redir_struct *next; /* pointer to the next redirect in the list */
192 glob_t word; /* *word.gl_pathv is the filename */
196 pid_t pid; /* 0 if exited */
197 char **argv; /* program name and arguments */
198 struct pipe *group; /* if non-NULL, first in group or subshell */
199 int subshell; /* flag, non-zero if group must be forked */
200 struct redir_struct *redirects; /* I/O redirections */
201 glob_t glob_result; /* result of parameter globbing */
202 int is_stopped; /* is the program currently running? */
203 struct pipe *family; /* pointer back to the child's parent pipe */
207 int jobid; /* job number */
208 int num_progs; /* total number of programs in job */
209 int running_progs; /* number of programs running */
210 char *text; /* name of job */
211 char *cmdbuf; /* buffer various argv's point into */
212 pid_t pgrp; /* process group ID for the job */
213 struct child_prog *progs; /* array of commands in pipe */
214 struct pipe *next; /* to track background commands */
215 int stopped_progs; /* number of programs alive, but stopped */
216 int job_context; /* bitmask defining current context */
217 pipe_style followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
218 reserved_style r_mode; /* supports if, for, while, until */
222 struct pipe *head; /* head of list of running jobs */
223 struct pipe *fg; /* current foreground job */
228 struct close_me *next;
231 /* globals, connect us to the outside world
232 * the first three support $?, $#, and $1 */
234 unsigned int global_argc;
235 unsigned int last_return_code;
236 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
238 /* Variables we export */
239 unsigned int shell_context; /* Used in cmdedit.c to reset the
240 * context when someone hits ^C */
242 /* "globals" within this file */
243 static char *ifs=NULL;
244 static char map[256];
245 static int fake_mode=0;
246 static int interactive=0;
247 static struct close_me *close_me_head = NULL;
248 static const char *cwd;
249 static struct jobset *job_list;
250 static unsigned int last_bg_pid=0;
252 static char *PS2 = "> ";
253 static char **__shell_local_env = 0;
255 #define B_CHUNK (100)
257 #define MAX_LINE 256 /* for cwd */
258 #define MAX_READ 256 /* for builtin_read */
267 #define NULL_O_STRING {NULL,0,0,0,0}
268 /* used for initialization:
269 o_string foo = NULL_O_STRING; */
271 /* I can almost use ordinary FILE *. Is open_memstream() universally
272 * available? Where is it documented? */
278 int (*get) (struct in_str *);
279 int (*peek) (struct in_str *);
281 #define b_getch(input) ((input)->get(input))
282 #define b_peek(input) ((input)->peek(input))
284 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
286 struct built_in_command {
287 char *cmd; /* name */
288 char *descr; /* description */
289 int (*function) (struct child_prog *); /* function ptr */
292 /* belongs in busybox.h */
293 static inline int max(int a, int b) {
297 /* This should be in utility.c */
299 static void debug_printf(const char *format, ...)
302 va_start(args, format);
303 vfprintf(stderr, format, args);
307 static void debug_printf(const char *format, ...) { }
309 #define final_printf debug_printf
311 void __syntax(char *file, int line) {
312 fprintf(stderr,"syntax error %s:%d\n",file,line);
314 #define syntax() __syntax(__FILE__, __LINE__)
316 /* Index of subroutines: */
317 /* function prototypes for builtins */
318 static int builtin_cd(struct child_prog *child);
319 static int builtin_env(struct child_prog *child);
320 static int builtin_exec(struct child_prog *child);
321 static int builtin_exit(struct child_prog *child);
322 static int builtin_export(struct child_prog *child);
323 static int builtin_fg_bg(struct child_prog *child);
324 static int builtin_help(struct child_prog *child);
325 static int builtin_jobs(struct child_prog *child);
326 static int builtin_pwd(struct child_prog *child);
327 static int builtin_read(struct child_prog *child);
328 static int builtin_shift(struct child_prog *child);
329 static int builtin_source(struct child_prog *child);
330 static int builtin_umask(struct child_prog *child);
331 static int builtin_unset(struct child_prog *child);
332 static int builtin_not_written(struct child_prog *child);
333 /* o_string manipulation: */
334 static int b_check_space(o_string *o, int len);
335 static int b_addchr(o_string *o, int ch);
336 static void b_reset(o_string *o);
337 static int b_addqchr(o_string *o, int ch, int quote);
338 static int b_adduint(o_string *o, unsigned int i);
339 /* in_str manipulations: */
340 static int static_get(struct in_str *i);
341 static int static_peek(struct in_str *i);
342 static int file_get(struct in_str *i);
343 static int file_peek(struct in_str *i);
344 static void setup_file_in_str(struct in_str *i, FILE *f);
345 static void setup_string_in_str(struct in_str *i, const char *s);
346 /* close_me manipulations: */
347 static void mark_open(int fd);
348 static void mark_closed(int fd);
349 static void close_all();
350 /* "run" the final data structures: */
351 static char *indenter(int i);
352 static int run_list_test(struct pipe *head, int indent);
353 static int run_pipe_test(struct pipe *pi, int indent);
354 /* really run the final data structures: */
355 static int setup_redirects(struct child_prog *prog, int squirrel[]);
356 static int pipe_wait(struct pipe *pi);
357 static int run_list_real(struct pipe *pi);
358 static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
359 static int run_pipe_real(struct pipe *pi);
360 /* extended glob support: */
361 static int globhack(const char *src, int flags, glob_t *pglob);
362 static int glob_needed(const char *s);
363 static int xglob(o_string *dest, int flags, glob_t *pglob);
364 /* variable assignment: */
365 static int set_local_var(const char *s);
366 static int is_assignment(const char *s);
367 /* data structure manipulation: */
368 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
369 static void initialize_context(struct p_context *ctx);
370 static int done_word(o_string *dest, struct p_context *ctx);
371 static int done_command(struct p_context *ctx);
372 static int done_pipe(struct p_context *ctx, pipe_style type);
373 /* primary string parsing: */
374 static int redirect_dup_num(struct in_str *input);
375 static int redirect_opt_num(o_string *o);
376 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
377 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
378 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src);
379 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
380 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
381 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
383 static int parse_stream_outer(struct in_str *inp);
384 static int parse_string_outer(const char *s);
385 static int parse_file_outer(FILE *f);
386 /* job management: */
387 static void checkjobs();
388 static void insert_bg_job(struct pipe *pi);
389 static void remove_bg_job(struct pipe *pi);
390 static void free_pipe(struct pipe *pi);
392 /* Table of built-in functions. They can be forked or not, depending on
393 * context: within pipes, they fork. As simple commands, they do not.
394 * When used in non-forking context, they can change global variables
395 * in the parent shell process. If forked, of course they can not.
396 * For example, 'unset foo | whatever' will parse and run, but foo will
397 * still be set at the end. */
398 static struct built_in_command bltins[] = {
399 {"bg", "Resume a job in the background", builtin_fg_bg},
400 {"break", "Exit for, while or until loop", builtin_not_written},
401 {"cd", "Change working directory", builtin_cd},
402 {"continue", "Continue for, while or until loop", builtin_not_written},
403 {"env", "Print all environment variables", builtin_env},
404 {"eval", "Construct and run shell command", builtin_not_written},
405 {"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
406 {"exit", "Exit from shell()", builtin_exit},
407 {"export", "Set environment variable", builtin_export},
408 {"fg", "Bring job into the foreground", builtin_fg_bg},
409 {"jobs", "Lists the active jobs", builtin_jobs},
410 {"pwd", "Print current directory", builtin_pwd},
411 {"read", "Input environment variable", builtin_read},
412 {"return", "Return from a function", builtin_not_written},
413 {"set", "Set/unset shell options", builtin_not_written},
414 {"shift", "Shift positional parameters", builtin_shift},
415 {"trap", "Trap signals", builtin_not_written},
416 {"ulimit","Controls resource limits", builtin_not_written},
417 {"umask","Sets file creation mask", builtin_umask},
418 {"unset", "Unset environment variable", builtin_unset},
419 {".", "Source-in and run commands in a file", builtin_source},
420 {"help", "List shell built-in commands", builtin_help},
424 /* built-in 'cd <path>' handler */
425 static int builtin_cd(struct child_prog *child)
428 if (child->argv[1] == NULL)
429 newdir = getenv("HOME");
431 newdir = child->argv[1];
433 printf("cd: %s: %s\n", newdir, strerror(errno));
436 cwd = xgetcwd((char *)cwd);
442 /* built-in 'env' handler */
443 static int builtin_env(struct child_prog *dummy)
446 if (e == NULL) return EXIT_FAILURE;
453 /* built-in 'exec' handler */
454 static int builtin_exec(struct child_prog *child)
456 if (child->argv[1] == NULL)
457 return EXIT_SUCCESS; /* Really? */
463 /* built-in 'exit' handler */
464 static int builtin_exit(struct child_prog *child)
466 if (child->argv[1] == NULL)
467 exit(last_return_code);
468 exit (atoi(child->argv[1]));
471 /* built-in 'export VAR=value' handler */
472 static int builtin_export(struct child_prog *child)
476 if (child->argv[1] == NULL) {
477 return (builtin_env(child));
479 /* FIXME -- I leak memory. This will be
480 * fixed up properly when we add local
481 * variable support -- I hope */
482 res = putenv(strdup(child->argv[1]));
484 fprintf(stderr, "export: %s\n", strerror(errno));
488 /* built-in 'fg' and 'bg' handler */
489 static int builtin_fg_bg(struct child_prog *child)
492 struct pipe *pi=NULL;
494 /* If they gave us no args, assume they want the last backgrounded task */
495 if (!child->argv[1]) {
496 for (pi = job_list->head; pi; pi = pi->next) {
497 if (pi->progs && pi->progs->pid == last_bg_pid) {
502 error_msg("%s: no current job", child->argv[0]);
506 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
507 error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
511 for (pi = job_list->head; pi; pi = pi->next) {
512 if (pi->jobid == jobnum) {
517 error_msg("%s: %d: no such job", child->argv[0], jobnum);
521 if (*child->argv[0] == 'f') {
522 /* Make this job the foreground job */
523 signal(SIGTTOU, SIG_IGN);
524 /* suppress messages when run from /linuxrc mag@sysgo.de */
525 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
526 perror_msg("tcsetpgrp");
527 signal(SIGTTOU, SIG_DFL);
531 /* Restart the processes in the job */
532 for (i = 0; i < pi->num_progs; i++)
533 pi->progs[i].is_stopped = 0;
535 kill(-pi->pgrp, SIGCONT);
537 pi->stopped_progs = 0;
541 /* built-in 'help' handler */
542 static int builtin_help(struct child_prog *dummy)
544 struct built_in_command *x;
546 printf("\nBuilt-in commands:\n");
547 printf("-------------------\n");
548 for (x = bltins; x->cmd; x++) {
551 printf("%s\t%s\n", x->cmd, x->descr);
557 /* built-in 'jobs' handler */
558 static int builtin_jobs(struct child_prog *child)
563 for (job = job_list->head; job; job = job->next) {
564 if (job->running_progs == job->stopped_progs)
565 status_string = "Stopped";
567 status_string = "Running";
568 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
574 /* built-in 'pwd' handler */
575 static int builtin_pwd(struct child_prog *dummy)
577 cwd = xgetcwd((char *)cwd);
584 /* built-in 'read VAR' handler */
585 static int builtin_read(struct child_prog *child)
587 int res = 0, len, newlen;
589 char string[MAX_READ];
591 if (child->argv[1]) {
592 /* argument (VAR) given: put "VAR=" into buffer */
593 strcpy(string, child->argv[1]);
594 len = strlen(string);
597 /* XXX would it be better to go through in_str? */
598 fgets(&string[len], sizeof(string) - len, stdin); /* read string */
599 newlen = strlen(string);
601 string[--newlen] = '\0'; /* chomp trailing newline */
603 ** string should now contain "VAR=<value>"
604 ** copy it (putenv() won't do that, so we must make sure
605 ** the string resides in a static buffer!)
608 if((s = strdup(string)))
611 fprintf(stderr, "read: %s\n", strerror(errno));
614 fgets(string, sizeof(string), stdin);
619 /* Built-in 'shift' handler */
620 static int builtin_shift(struct child_prog *child)
623 if (child->argv[1]) {
624 n=atoi(child->argv[1]);
626 if (n>=0 && n<global_argc) {
627 /* XXX This probably breaks $0 */
636 /* Built-in '.' handler (read-in and execute commands from file) */
637 static int builtin_source(struct child_prog *child)
642 if (child->argv[1] == NULL)
645 /* XXX search through $PATH is missing */
646 input = fopen(child->argv[1], "r");
648 fprintf(stderr, "Couldn't open file '%s'\n", child->argv[1]);
652 /* Now run the file */
653 /* XXX argv and argc are broken; need to save old global_argv
654 * (pointer only is OK!) on this stack frame,
655 * set global_argv=child->argv+1, recurse, and restore. */
656 mark_open(fileno(input));
657 status = parse_file_outer(input);
658 mark_closed(fileno(input));
663 static int builtin_umask(struct child_prog *child)
666 const char *arg = child->argv[1];
669 new_umask=strtoul(arg, &end, 8);
670 if (*end!='\0' || end == arg) {
674 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
680 /* built-in 'unset VAR' handler */
681 static int builtin_unset(struct child_prog *child)
683 if (child->argv[1] == NULL) {
684 fprintf(stderr, "unset: parameter required.\n");
687 unsetenv(child->argv[1]);
691 static int builtin_not_written(struct child_prog *child)
693 printf("builtin_%s not written\n",child->argv[0]);
697 static int b_check_space(o_string *o, int len)
699 /* It would be easy to drop a more restrictive policy
700 * in here, such as setting a maximum string length */
701 if (o->length + len > o->maxlen) {
702 char *old_data = o->data;
703 /* assert (data == NULL || o->maxlen != 0); */
704 o->maxlen += max(2*len, B_CHUNK);
705 o->data = realloc(o->data, 1 + o->maxlen);
706 if (o->data == NULL) {
710 return o->data == NULL;
713 static int b_addchr(o_string *o, int ch)
715 debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
716 if (b_check_space(o, 1)) return B_NOSPAC;
717 o->data[o->length] = ch;
719 o->data[o->length] = '\0';
723 static void b_reset(o_string *o)
727 if (o->data != NULL) *o->data = '\0';
730 static void b_free(o_string *o)
733 if (o->data != NULL) free(o->data);
738 /* My analysis of quoting semantics tells me that state information
739 * is associated with a destination, not a source.
741 static int b_addqchr(o_string *o, int ch, int quote)
743 if (quote && strchr("*?[\\",ch)) {
745 rc = b_addchr(o, '\\');
748 return b_addchr(o, ch);
751 /* belongs in utility.c */
752 char *simple_itoa(unsigned int i)
754 /* 21 digits plus null terminator, good for 64-bit or smaller ints */
755 static char local[22];
756 char *p = &local[21];
765 static int b_adduint(o_string *o, unsigned int i)
768 char *p = simple_itoa(i);
769 /* no escape checking necessary */
770 do r=b_addchr(o, *p++); while (r==0 && *p);
774 static int static_get(struct in_str *i)
777 if (ch=='\0') return EOF;
781 static int static_peek(struct in_str *i)
786 static inline void cmdedit_set_initial_prompt(void)
788 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
797 static inline void setup_prompt_string(int promptmode, char **prompt_str)
799 debug_printf("setup_prompt_string %d ",promptmode);
800 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
801 /* Set up the prompt */
802 if (promptmode == 1) {
805 PS1=xmalloc(strlen(cwd)+4);
806 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# ");
812 *prompt_str = (promptmode==0)? PS1 : PS2;
814 debug_printf("result %s\n",*prompt_str);
817 static void get_user_input(struct in_str *i)
820 static char the_command[BUFSIZ];
822 setup_prompt_string(i->promptmode, &prompt_str);
823 #ifdef BB_FEATURE_COMMAND_EDITING
825 ** enable command line editing only while a command line
826 ** is actually being read; otherwise, we'll end up bequeathing
827 ** atexit() handlers and other unwanted stuff to our
828 ** child processes (rob@sysgo.de)
830 cmdedit_read_input(prompt_str, the_command);
833 fputs(prompt_str, stdout);
835 the_command[0]=fgetc(i->file);
841 /* This is the magic location that prints prompts
842 * and gets data back from the user */
843 static int file_get(struct in_str *i)
848 /* If there is data waiting, eat it up */
852 /* need to double check i->file because we might be doing something
853 * more complicated by now, like sourcing or substituting. */
854 if (i->__promptme && interactive && i->file == stdin) {
865 debug_printf("b_getch: got a %d\n", ch);
867 if (ch == '\n') i->__promptme=1;
871 /* All the callers guarantee this routine will never be
872 * used right after a newline, so prompting is not needed.
874 static int file_peek(struct in_str *i)
879 static char buffer[2];
880 buffer[0] = fgetc(i->file);
883 debug_printf("b_peek: got a %d\n", *i->p);
888 static void setup_file_in_str(struct in_str *i, FILE *f)
898 static void setup_string_in_str(struct in_str *i, const char *s)
900 i->peek = static_peek;
907 static void mark_open(int fd)
909 struct close_me *new = xmalloc(sizeof(struct close_me));
911 new->next = close_me_head;
915 static void mark_closed(int fd)
917 struct close_me *tmp;
918 if (close_me_head == NULL || close_me_head->fd != fd)
919 error_msg_and_die("corrupt close_me");
921 close_me_head = close_me_head->next;
925 static void close_all()
928 for (c=close_me_head; c; c=c->next) {
931 close_me_head = NULL;
934 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
935 * and stderr if they are redirected. */
936 static int setup_redirects(struct child_prog *prog, int squirrel[])
939 struct redir_struct *redir;
941 for (redir=prog->redirects; redir; redir=redir->next) {
942 if (redir->dup == -1) {
943 mode=redir_table[redir->type].mode;
944 openfd = open(redir->word.gl_pathv[0], mode, 0666);
946 /* this could get lost if stderr has been redirected, but
947 bash and ash both lose it as well (though zsh doesn't!) */
948 fprintf(stderr,"error opening %s: %s\n", redir->word.gl_pathv[0],
956 if (openfd != redir->fd) {
957 if (squirrel && redir->fd < 3) {
958 squirrel[redir->fd] = dup(redir->fd);
963 dup2(openfd, redir->fd);
971 static void restore_redirects(int squirrel[])
974 for (i=0; i<3; i++) {
977 /* No error checking. I sure wouldn't know what
978 * to do with an error if I found one! */
985 /* XXX this definitely needs some more thought, work, and
986 * cribbing from other shells */
987 static int pipe_wait(struct pipe *pi)
989 int rcode=0, i, pid, running, status;
990 running = pi->num_progs;
992 pid=waitpid(-1, &status, 0);
993 if (pid < 0) perror_msg_and_die("waitpid");
994 for (i=0; i < pi->num_progs; i++) {
995 if (pi->progs[i].pid == pid) {
996 if (i==pi->num_progs-1) rcode=WEXITSTATUS(status);
997 pi->progs[i].pid = 0;
1006 /* very simple version for testing */
1007 static void pseudo_exec(struct child_prog *child)
1010 struct built_in_command *x;
1012 for (i=0; is_assignment(child->argv[i]); i++) {
1013 putenv(strdup(child->argv[i]));
1015 child->argv+=i; /* XXX this hack isn't so horrible, since we are about
1016 to exit, and therefore don't need to keep data
1017 structures consistent for free() use. */
1018 /* If a variable is assigned in a forest, and nobody listens,
1019 * was it ever really set?
1021 if (child->argv[0] == NULL) exit(EXIT_SUCCESS);
1024 * Check if the command matches any of the builtins.
1025 * Depending on context, this might be redundant. But it's
1026 * easier to waste a few CPU cycles than it is to figure out
1027 * if this is one of those cases.
1029 for (x = bltins; x->cmd; x++) {
1030 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1031 debug_printf("builtin exec %s\n", child->argv[0]);
1032 exit(x->function(child));
1036 /* Check if the command matches any busybox internal commands
1038 * FIXME: This feature is not 100% safe, since
1039 * BusyBox is not fully reentrant, so we have no guarantee the things
1040 * from the .bss are still zeroed, or that things from .data are still
1041 * at their defaults. We could exec ourself from /proc/self/exe, but I
1042 * really dislike relying on /proc for things. We could exec ourself
1043 * from global_argv[0], but if we are in a chroot, we may not be able
1044 * to find ourself... */
1045 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1048 char** argv_l=child->argv;
1049 char *name = child->argv[0];
1051 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1052 /* Following discussions from November 2000 on the busybox mailing
1053 * list, the default configuration, (without
1054 * get_last_path_component()) lets the user force use of an
1055 * external command by specifying the full (with slashes) filename.
1056 * If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then applets
1057 * _aways_ override external commands, so if you want to run
1058 * /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
1059 * filesystem and is _not_ busybox. Some systems may want this,
1061 name = get_last_path_component(name);
1063 /* Count argc for use in a second... */
1064 for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1066 debug_printf("running applet %s\n", name);
1067 run_applet_by_name(name, argc_l, child->argv);
1070 debug_printf("exec of %s\n",child->argv[0]);
1071 execvp(child->argv[0],child->argv);
1074 } else if (child->group) {
1075 debug_printf("runtime nesting to group\n");
1076 interactive=0; /* crucial!!!! */
1077 rcode = run_list_real(child->group);
1078 /* OK to leak memory by not calling run_list_test,
1079 * since this process is about to exit */
1082 /* Can happen. See what bash does with ">foo" by itself. */
1083 debug_printf("trying to pseudo_exec null command\n");
1088 static void insert_bg_job(struct pipe *pi)
1090 struct pipe *thejob;
1092 /* Linear search for the ID of the job to use */
1094 for (thejob = job_list->head; thejob; thejob = thejob->next)
1095 if (thejob->jobid >= pi->jobid)
1096 pi->jobid = thejob->jobid + 1;
1098 /* add thejob to the list of running jobs */
1099 if (!job_list->head) {
1100 thejob = job_list->head = xmalloc(sizeof(*thejob));
1102 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1103 thejob->next = xmalloc(sizeof(*thejob));
1104 thejob = thejob->next;
1107 /* physically copy the struct job */
1108 memcpy(thejob, pi, sizeof(struct pipe));
1109 thejob->next = NULL;
1110 thejob->running_progs = thejob->num_progs;
1111 thejob->stopped_progs = 0;
1112 thejob->text = xmalloc(MAX_LINE);
1114 //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1116 char *bar=thejob->text;
1117 char **foo=pi->progs[0].argv;
1118 while(foo && *foo) {
1119 bar += sprintf(bar, "%s ", *foo++);
1123 /* we don't wait for background thejobs to return -- append it
1124 to the list of backgrounded thejobs and leave it alone */
1125 printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1126 last_bg_pid = thejob->progs[0].pid;
1129 /* remove a backgrounded job from a jobset */
1130 static void remove_bg_job(struct pipe *pi)
1132 struct pipe *prev_pipe;
1135 if (pi == job_list->head) {
1136 job_list->head = pi->next;
1138 prev_pipe = job_list->head;
1139 while (prev_pipe->next != pi)
1140 prev_pipe = prev_pipe->next;
1141 prev_pipe->next = pi->next;
1147 /* free up all memory from a pipe */
1148 static void free_pipe(struct pipe *pi)
1152 for (i = 0; i < pi->num_progs; i++) {
1153 free(pi->progs[i].argv);
1154 if (pi->progs[i].redirects)
1155 free(pi->progs[i].redirects);
1163 memset(pi, 0, sizeof(struct pipe));
1167 /* Checks to see if any background processes have exited -- if they
1168 have, figure out why and see if a job has completed */
1169 static void checkjobs()
1176 while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
1177 for (pi = job_list->head; pi; pi = pi->next) {
1179 while (prognum < pi->num_progs &&
1180 pi->progs[prognum].pid != childpid) prognum++;
1181 if (prognum < pi->num_progs)
1185 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1187 pi->running_progs--;
1188 pi->progs[prognum].pid = 0;
1190 if (!pi->running_progs) {
1191 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1198 pi->stopped_progs++;
1199 pi->progs[prognum].is_stopped = 1;
1201 if (pi->stopped_progs == pi->num_progs) {
1202 printf(JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
1207 if (childpid == -1 && errno != ECHILD)
1208 perror_msg("waitpid");
1210 /* move the shell to the foreground */
1211 if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
1212 perror_msg("tcsetpgrp");
1215 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1216 * to finish. See pipe_wait().
1218 * return code is normally -1, when the caller has to wait for children
1219 * to finish to determine the exit status of the pipe. If the pipe
1220 * is a simple builtin command, however, the action is done by the
1221 * time run_pipe_real returns, and the exit code is provided as the
1224 * The input of the pipe is always stdin, the output is always
1225 * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1226 * because it tries to avoid running the command substitution in
1227 * subshell, when that is in fact necessary. The subshell process
1228 * now has its stdout directed to the input of the appropriate pipe,
1229 * so this routine is noticeably simpler.
1231 static int run_pipe_real(struct pipe *pi)
1235 int nextin, nextout;
1236 int pipefds[2]; /* pipefds[0] is for reading */
1237 struct child_prog *child;
1238 struct built_in_command *x;
1244 /* Check if we are supposed to run in the foreground */
1245 if (interactive && pi->followup!=PIPE_BG) {
1246 if ((pi->pgrp = tcgetpgrp(ctty = 2)) < 0
1247 && (pi->pgrp = tcgetpgrp(ctty = 0)) < 0
1248 && (pi->pgrp = tcgetpgrp(ctty = 1)) < 0)
1249 return errno = ENOTTY, -1;
1251 if (pi->pgrp < 0 && pi->pgrp != getpgrp())
1252 return errno = EPERM, -1;
1255 /* Check if this is a simple builtin (not part of a pipe).
1256 * Builtins within pipes have to fork anyway, and are handled in
1257 * pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
1259 if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1260 child = & (pi->progs[0]);
1261 if (child->group && ! child->subshell) {
1262 int squirrel[] = {-1, -1, -1};
1264 debug_printf("non-subshell grouping\n");
1265 setup_redirects(child, squirrel);
1266 /* XXX could we merge code with following builtin case,
1267 * by creating a pseudo builtin that calls run_list_real? */
1268 rcode = run_list_real(child->group);
1269 restore_redirects(squirrel);
1272 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1273 if (i!=0 && child->argv[i]==NULL) {
1274 /* assignments, but no command: set the local environment */
1275 for (i=0; child->argv[i]!=NULL; i++) {
1276 set_local_var(child->argv[i]);
1278 return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */
1280 for (x = bltins; x->cmd; x++) {
1281 if (strcmp(child->argv[i], x->cmd) == 0 ) {
1282 int squirrel[] = {-1, -1, -1};
1284 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1285 debug_printf("magic exec\n");
1286 setup_redirects(child,NULL);
1287 return EXIT_SUCCESS;
1289 debug_printf("builtin inline %s\n", child->argv[0]);
1290 /* XXX setup_redirects acts on file descriptors, not FILEs.
1291 * This is perfect for work that comes after exec().
1292 * Is it really safe for inline use? Experimentally,
1293 * things seem to work with glibc. */
1294 setup_redirects(child, squirrel);
1295 for (i=0; is_assignment(child->argv[i]); i++) {
1296 putenv(strdup(child->argv[i]));
1298 child->argv+=i; /* XXX horrible hack */
1299 rcode = x->function(child);
1300 child->argv-=i; /* XXX restore hack so free() can work right */
1301 restore_redirects(squirrel);
1307 for (i = 0; i < pi->num_progs; i++) {
1308 child = & (pi->progs[i]);
1310 /* pipes are inserted between pairs of commands */
1311 if ((i + 1) < pi->num_progs) {
1312 if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1313 nextout = pipefds[1];
1319 /* XXX test for failed fork()? */
1320 if (!(child->pid = fork())) {
1322 signal(SIGTTOU, SIG_DFL);
1334 if (pipefds[0]!=-1) {
1335 close(pipefds[0]); /* opposite end of our output pipe */
1338 /* Like bash, explicit redirects override pipes,
1339 * and the pipe fd is available for dup'ing. */
1340 setup_redirects(child,NULL);
1342 if (pi->followup!=PIPE_BG) {
1343 /* Put our child in the process group whose leader is the
1344 * first process in this pipe. */
1346 pi->pgrp = child->pid;
1348 /* Don't check for errors. The child may be dead already,
1349 * in which case setpgid returns error code EACCES. */
1350 if (setpgid(0, pi->pgrp) == 0) {
1351 signal(SIGTTOU, SIG_IGN);
1352 tcsetpgrp(ctty, pi->pgrp);
1353 signal(SIGTTOU, SIG_DFL);
1359 /* Put our child in the process group whose leader is the
1360 * first process in this pipe. */
1362 pi->pgrp = child->pid;
1364 /* Don't check for errors. The child may be dead already,
1365 * in which case setpgid returns error code EACCES. */
1366 setpgid(child->pid, pi->pgrp);
1373 /* If there isn't another process, nextin is garbage
1374 but it doesn't matter */
1375 nextin = pipefds[0];
1380 static int run_list_real(struct pipe *pi)
1383 int if_code=0, next_if_code=0; /* need double-buffer to handle elif */
1384 reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1385 for (;pi;pi=pi->next) {
1387 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);
1388 if (rmode == skip_more_in_this_rmode) continue;
1389 skip_more_in_this_rmode = RES_XXXX;
1390 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1391 if (rmode == RES_THEN && if_code) continue;
1392 if (rmode == RES_ELSE && !if_code) continue;
1393 if (rmode == RES_ELIF && !if_code) continue;
1394 if (pi->num_progs == 0) continue;
1395 rcode = run_pipe_real(pi);
1397 /* We only ran a builtin: rcode was set by the return value
1398 * of run_pipe_real(), and we don't need to wait for anything. */
1399 } else if (pi->followup==PIPE_BG) {
1400 /* XXX check bash's behavior with nontrivial pipes */
1401 /* XXX compute jobid */
1402 /* XXX what does bash do with attempts to background builtins? */
1404 rcode = EXIT_SUCCESS;
1408 /* move the new process group into the foreground */
1409 /* suppress messages when run from /linuxrc mag@sysgo.de */
1410 //signal(SIGTTIN, SIG_IGN);
1411 //signal(SIGTTOU, SIG_IGN);
1412 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
1413 perror_msg("tcsetpgrp");
1414 rcode = pipe_wait(pi);
1415 if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
1416 perror_msg("tcsetpgrp");
1417 //signal(SIGTTIN, SIG_DFL);
1418 //signal(SIGTTOU, SIG_DFL);
1420 rcode = pipe_wait(pi);
1423 last_return_code=rcode;
1424 if ( rmode == RES_IF || rmode == RES_ELIF )
1425 next_if_code=rcode; /* can be overwritten a number of times */
1426 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1427 (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1428 skip_more_in_this_rmode=rmode;
1429 /* return rcode; */ /* XXX broken if list is part of if/then/else */
1435 /* broken, of course, but OK for testing */
1436 static char *indenter(int i)
1438 static char blanks[]=" ";
1439 return &blanks[sizeof(blanks)-i-1];
1442 /* return code is the exit status of the pipe */
1443 static int run_pipe_test(struct pipe *pi, int indent)
1446 struct child_prog *child;
1447 struct redir_struct *r, *rnext;
1448 int a, i, ret_code=0;
1449 char *ind = indenter(indent);
1450 final_printf("%s run pipe: (pid %d)\n",ind,getpid());
1451 for (i=0; i<pi->num_progs; i++) {
1452 child = &pi->progs[i];
1453 final_printf("%s command %d:\n",ind,i);
1455 for (a=0,p=child->argv; *p; a++,p++) {
1456 final_printf("%s argv[%d] = %s\n",ind,a,*p);
1458 globfree(&child->glob_result);
1460 } else if (child->group) {
1461 final_printf("%s begin group (subshell:%d)\n",ind, child->subshell);
1462 ret_code = run_list_test(child->group,indent+3);
1463 final_printf("%s end group\n",ind);
1465 final_printf("%s (nil)\n",ind);
1467 for (r=child->redirects; r; r=rnext) {
1468 final_printf("%s redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
1470 final_printf(" %s\n", *r->word.gl_pathv);
1473 final_printf("&%d\n", r->dup);
1478 child->redirects=NULL;
1480 free(pi->progs); /* children are an array, they get freed all at once */
1485 static int run_list_test(struct pipe *head, int indent)
1487 int rcode=0; /* if list has no members */
1488 struct pipe *pi, *next;
1489 char *ind = indenter(indent);
1490 for (pi=head; pi; pi=next) {
1491 if (pi->num_progs == 0) break;
1492 final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
1493 rcode = run_pipe_test(pi, indent);
1494 final_printf("%s pipe followup code %d\n", ind, pi->followup);
1502 /* Select which version we will use */
1503 static int run_list(struct pipe *pi)
1507 rcode = run_list_real(pi);
1509 /* run_list_test has the side effect of clearing memory
1510 * In the long run that function can be merged with run_list_real,
1511 * but doing that now would hobble the debugging effort. */
1512 run_list_test(pi,0);
1516 /* The API for glob is arguably broken. This routine pushes a non-matching
1517 * string into the output structure, removing non-backslashed backslashes.
1518 * If someone can prove me wrong, by performing this function within the
1519 * original glob(3) api, feel free to rewrite this routine into oblivion.
1520 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1521 * XXX broken if the last character is '\\', check that before calling.
1523 static int globhack(const char *src, int flags, glob_t *pglob)
1528 for (cnt=1, s=src; *s; s++) {
1529 if (*s == '\\') s++;
1533 if (!dest) return GLOB_NOSPACE;
1534 if (!(flags & GLOB_APPEND)) {
1535 pglob->gl_pathv=NULL;
1540 pathc = ++pglob->gl_pathc;
1541 pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1542 if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1543 pglob->gl_pathv[pathc-1]=dest;
1544 pglob->gl_pathv[pathc]=NULL;
1545 for (s=src; *s; s++, dest++) {
1546 if (*s == '\\') s++;
1553 /* XXX broken if the last character is '\\', check that before calling */
1554 static int glob_needed(const char *s)
1557 if (*s == '\\') s++;
1558 if (strchr("*[?",*s)) return 1;
1564 static void globprint(glob_t *pglob)
1567 debug_printf("glob_t at %p:\n", pglob);
1568 debug_printf(" gl_pathc=%d gl_pathv=%p gl_offs=%d gl_flags=%d\n",
1569 pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
1570 for (i=0; i<pglob->gl_pathc; i++)
1571 debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
1572 pglob->gl_pathv[i], pglob->gl_pathv[i]);
1576 static int xglob(o_string *dest, int flags, glob_t *pglob)
1580 /* short-circuit for null word */
1581 /* we can code this better when the debug_printf's are gone */
1582 if (dest->length == 0) {
1583 if (dest->nonnull) {
1584 /* bash man page calls this an "explicit" null */
1585 gr = globhack(dest->data, flags, pglob);
1586 debug_printf("globhack returned %d\n",gr);
1590 } else if (glob_needed(dest->data)) {
1591 gr = glob(dest->data, flags, NULL, pglob);
1592 debug_printf("glob returned %d\n",gr);
1593 if (gr == GLOB_NOMATCH) {
1594 /* quote removal, or more accurately, backslash removal */
1595 gr = globhack(dest->data, flags, pglob);
1596 debug_printf("globhack returned %d\n",gr);
1599 gr = globhack(dest->data, flags, pglob);
1600 debug_printf("globhack returned %d\n",gr);
1602 if (gr == GLOB_NOSPACE) {
1603 fprintf(stderr,"out of memory during glob\n");
1606 if (gr != 0) { /* GLOB_ABORTED ? */
1607 fprintf(stderr,"glob(3) error %d\n",gr);
1609 /* globprint(glob_target); */
1613 /* This is used to set local variables (i.e. stuff not going into the environment) */
1614 static int set_local_var(const char *s)
1617 char *tmp,*name, *value;
1625 /* Assume when we enter this function that we are already in
1626 * NAME=VALUE format. So the first order of business is to
1627 * split 's' on the '=' into 'name' and 'value' */
1628 value = strchr(name, '=');
1635 printf("name='%s' and value='%s'\n",name, value);
1637 namelen = strlen (name);
1638 vallen = strlen (value);
1640 /* Now see how many local environment entries we have, and check
1641 * if we match an existing environment entry (so we can overwrite it) */
1643 for (ep = __shell_local_env; ep && *ep != NULL; ++ep) {
1644 if (!memcmp (*ep, name, namelen) && (*ep)[namelen] == '=')
1650 if (ep == NULL || *ep == NULL) {
1651 static char **last_environ = NULL;
1652 char **new_environ = (char **) malloc((size + 2) * sizeof(char *));
1653 if (new_environ == NULL) {
1657 memcpy((__ptr_t) new_environ, (__ptr_t) __shell_local_env, size * sizeof(char *));
1659 new_environ[size] = malloc (namelen + 1 + vallen + 1);
1660 if (new_environ[size] == NULL) {
1666 memcpy (new_environ[size], name, namelen);
1667 new_environ[size][namelen] = '=';
1668 memcpy (&new_environ[size][namelen + 1], value, vallen + 1);
1670 new_environ[size + 1] = NULL;
1672 if (last_environ != NULL)
1673 free ((__ptr_t) last_environ);
1674 last_environ = new_environ;
1675 __shell_local_env = new_environ;
1678 size_t len = strlen (*ep);
1679 if (len < namelen + 1 + vallen) {
1680 char *new = malloc (namelen + 1 + vallen + 1);
1686 memcpy (*ep, name, namelen);
1687 (*ep)[namelen] = '=';
1689 memcpy (&(*ep)[namelen + 1], value, vallen + 1);
1697 char *get_local_var(const char *var)
1704 if (!__shell_local_env)
1707 for (p = __shell_local_env; *p; p++) {
1708 if (memcmp(var, *p, len) == 0 && (*p)[len] == '=')
1709 return *p + len + 1;
1714 static int is_assignment(const char *s)
1716 if (s==NULL || !isalpha(*s)) return 0;
1718 while(isalnum(*s) || *s=='_') ++s;
1722 /* the src parameter allows us to peek forward to a possible &n syntax
1723 * for file descriptor duplication, e.g., "2>&1".
1724 * Return code is 0 normally, 1 if a syntax error is detected in src.
1725 * Resource errors (in xmalloc) cause the process to exit */
1726 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1727 struct in_str *input)
1729 struct child_prog *child=ctx->child;
1730 struct redir_struct *redir = child->redirects;
1731 struct redir_struct *last_redir=NULL;
1733 /* Create a new redir_struct and drop it onto the end of the linked list */
1738 redir = xmalloc(sizeof(struct redir_struct));
1741 last_redir->next=redir;
1743 child->redirects=redir;
1747 redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1749 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1751 /* Check for a '2>&1' type redirect */
1752 redir->dup = redirect_dup_num(input);
1753 if (redir->dup == -2) return 1; /* syntax error */
1754 if (redir->dup != -1) {
1755 /* Erik had a check here that the file descriptor in question
1756 * is legit; I postpone that to "run time"
1757 * A "-" representation of "close me" shows up as a -3 here */
1758 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1760 /* We do _not_ try to open the file that src points to,
1761 * since we need to return and let src be expanded first.
1762 * Set ctx->pending_redirect, so we know what to do at the
1763 * end of the next parsed word.
1765 ctx->pending_redirect = redir;
1770 struct pipe *new_pipe(void) {
1772 pi = xmalloc(sizeof(struct pipe));
1776 pi->followup = 0; /* invalid */
1780 static void initialize_context(struct p_context *ctx)
1783 ctx->pending_redirect=NULL;
1785 ctx->list_head=new_pipe();
1786 ctx->pipe=ctx->list_head;
1789 done_command(ctx); /* creates the memory for working child */
1792 /* normal return is 0
1793 * if a reserved word is found, and processed, return 1
1794 * should handle if, then, elif, else, fi, for, while, until, do, done.
1795 * case, function, and select are obnoxious, save those for later.
1797 int reserved_word(o_string *dest, struct p_context *ctx)
1799 struct reserved_combo {
1804 /* Mostly a list of accepted follow-up reserved words.
1805 * FLAG_END means we are done with the sequence, and are ready
1806 * to turn the compound list into a command.
1807 * FLAG_START means the word must start a new compound list.
1809 static struct reserved_combo reserved_list[] = {
1810 { "if", RES_IF, FLAG_THEN | FLAG_START },
1811 { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
1812 { "elif", RES_ELIF, FLAG_THEN },
1813 { "else", RES_ELSE, FLAG_FI },
1814 { "fi", RES_FI, FLAG_END },
1815 { "for", RES_FOR, FLAG_DO | FLAG_START },
1816 { "while", RES_WHILE, FLAG_DO | FLAG_START },
1817 { "until", RES_UNTIL, FLAG_DO | FLAG_START },
1818 { "do", RES_DO, FLAG_DONE },
1819 { "done", RES_DONE, FLAG_END }
1821 struct reserved_combo *r;
1822 for (r=reserved_list;
1823 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
1824 r<reserved_list+NRES; r++) {
1825 if (strcmp(dest->data, r->literal) == 0) {
1826 debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
1827 if (r->flag & FLAG_START) {
1828 struct p_context *new = xmalloc(sizeof(struct p_context));
1829 debug_printf("push stack\n");
1830 *new = *ctx; /* physical copy */
1831 initialize_context(ctx);
1833 } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
1840 ctx->old_flag = r->flag;
1841 if (ctx->old_flag & FLAG_END) {
1842 struct p_context *old;
1843 debug_printf("pop stack\n");
1845 old->child->group = ctx->list_head;
1846 *ctx = *old; /* physical copy */
1856 /* normal return is 0.
1857 * Syntax or xglob errors return 1. */
1858 static int done_word(o_string *dest, struct p_context *ctx)
1860 struct child_prog *child=ctx->child;
1861 glob_t *glob_target;
1864 debug_printf("done_word: %s %p\n", dest->data, child);
1865 if (dest->length == 0 && !dest->nonnull) {
1866 debug_printf(" true null, ignored\n");
1869 if (ctx->pending_redirect) {
1870 glob_target = &ctx->pending_redirect->word;
1874 return 1; /* syntax error, groups and arglists don't mix */
1877 debug_printf("checking %s for reserved-ness\n",dest->data);
1878 if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
1880 glob_target = &child->glob_result;
1881 if (child->argv) flags |= GLOB_APPEND;
1883 gr = xglob(dest, flags, glob_target);
1884 if (gr != 0) return 1;
1887 if (ctx->pending_redirect) {
1888 ctx->pending_redirect=NULL;
1889 if (glob_target->gl_pathc != 1) {
1890 fprintf(stderr, "ambiguous redirect\n");
1894 child->argv = glob_target->gl_pathv;
1899 /* The only possible error here is out of memory, in which case
1901 static int done_command(struct p_context *ctx)
1903 /* The child is really already in the pipe structure, so
1904 * advance the pipe counter and make a new, null child.
1905 * Only real trickiness here is that the uncommitted
1906 * child structure, to which ctx->child points, is not
1907 * counted in pi->num_progs. */
1908 struct pipe *pi=ctx->pipe;
1909 struct child_prog *prog=ctx->child;
1911 if (prog && prog->group == NULL
1912 && prog->argv == NULL
1913 && prog->redirects == NULL) {
1914 debug_printf("done_command: skipping null command\n");
1918 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
1920 debug_printf("done_command: initializing\n");
1922 pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
1924 prog = pi->progs + pi->num_progs;
1925 prog->redirects = NULL;
1927 prog->is_stopped = 0;
1929 prog->glob_result.gl_pathv = NULL;
1933 /* but ctx->pipe and ctx->list_head remain unchanged */
1937 static int done_pipe(struct p_context *ctx, pipe_style type)
1940 done_command(ctx); /* implicit closure of previous command */
1941 debug_printf("done_pipe, type %d\n", type);
1942 ctx->pipe->followup = type;
1943 ctx->pipe->r_mode = ctx->w;
1945 ctx->pipe->next = new_p;
1948 done_command(ctx); /* set up new pipe to accept commands */
1952 /* peek ahead in the in_str to find out if we have a "&n" construct,
1953 * as in "2>&1", that represents duplicating a file descriptor.
1954 * returns either -2 (syntax error), -1 (no &), or the number found.
1956 static int redirect_dup_num(struct in_str *input)
1960 if (ch != '&') return -1;
1962 b_getch(input); /* get the & */
1966 return -3; /* "-" represents "close me" */
1968 while (isdigit(ch)) {
1976 fprintf(stderr, "ambiguous redirect\n");
1980 /* If a redirect is immediately preceded by a number, that number is
1981 * supposed to tell which file descriptor to redirect. This routine
1982 * looks for such preceding numbers. In an ideal world this routine
1983 * needs to handle all the following classes of redirects...
1984 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
1985 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
1986 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
1987 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
1988 * A -1 output from this program means no valid number was found, so the
1989 * caller should use the appropriate default for this redirection.
1991 static int redirect_opt_num(o_string *o)
1995 if (o->length==0) return -1;
1996 for(num=0; num<o->length; num++) {
1997 if (!isdigit(*(o->data+num))) {
2001 /* reuse num (and save an int) */
2007 FILE *generate_stream_from_list(struct pipe *head)
2011 int pid, channel[2];
2012 if (pipe(channel)<0) perror_msg_and_die("pipe");
2015 perror_msg_and_die("fork");
2016 } else if (pid==0) {
2018 if (channel[1] != 1) {
2023 #define SURROGATE "surrogate response"
2024 write(1,SURROGATE,sizeof(SURROGATE));
2025 exit(run_list(head));
2027 exit(run_list_real(head)); /* leaks memory */
2030 debug_printf("forked child %d\n",pid);
2032 pf = fdopen(channel[0],"r");
2033 debug_printf("pipe on FILE *%p\n",pf);
2035 run_list_test(head,0);
2036 pf=popen("echo surrogate response","r");
2037 debug_printf("started fake pipe on FILE *%p\n",pf);
2042 /* this version hacked for testing purposes */
2043 /* return code is exit status of the process that is run. */
2044 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2047 o_string result=NULL_O_STRING;
2048 struct p_context inner;
2050 struct in_str pipe_str;
2051 initialize_context(&inner);
2053 /* recursion to generate command */
2054 retcode = parse_stream(&result, &inner, input, subst_end);
2055 if (retcode != 0) return retcode; /* syntax error or EOF */
2056 done_word(&result, &inner);
2057 done_pipe(&inner, PIPE_SEQ);
2060 p=generate_stream_from_list(inner.list_head);
2061 if (p==NULL) return 1;
2062 mark_open(fileno(p));
2063 setup_file_in_str(&pipe_str, p);
2065 /* now send results of command back into original context */
2066 retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2067 /* XXX In case of a syntax error, should we try to kill the child?
2068 * That would be tough to do right, so just read until EOF. */
2070 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2073 debug_printf("done reading from pipe, pclose()ing\n");
2074 /* This is the step that wait()s for the child. Should be pretty
2075 * safe, since we just read an EOF from its stdout. We could try
2076 * to better, by using wait(), and keeping track of background jobs
2077 * at the same time. That would be a lot of work, and contrary
2078 * to the KISS philosophy of this program. */
2079 mark_closed(fileno(p));
2081 debug_printf("pclosed, retcode=%d\n",retcode);
2082 /* XXX this process fails to trim a single trailing newline */
2086 static int parse_group(o_string *dest, struct p_context *ctx,
2087 struct in_str *input, int ch)
2090 struct p_context sub;
2091 struct child_prog *child = ctx->child;
2094 return 1; /* syntax error, groups and arglists don't mix */
2096 initialize_context(&sub);
2098 case '(': endch=')'; child->subshell=1; break;
2099 case '{': endch='}'; break;
2100 default: syntax(); /* really logic error */
2102 rcode=parse_stream(dest,&sub,input,endch);
2103 done_word(dest,&sub); /* finish off the final word in the subcontext */
2104 done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
2105 child->group = sub.list_head;
2107 /* child remains "open", available for possible redirects */
2110 /* basically useful version until someone wants to get fancier,
2111 * see the bash man page under "Parameter Expansion" */
2112 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src)
2116 p = get_local_var(src->data);
2117 if (!p) p = getenv(src->data);
2119 if (p) parse_string(dest, ctx, p); /* recursion */
2123 /* return code: 0 for OK, 1 for syntax error */
2124 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2127 o_string alt=NULL_O_STRING;
2129 int ch = input->peek(input); /* first character after the $ */
2130 debug_printf("handle_dollar: ch=%c\n",ch);
2132 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2136 lookup_param(dest, ctx, &alt);
2137 } else if (isdigit(ch)) {
2138 i = ch-'0'; /* XXX is $0 special? */
2139 if (i<global_argc) {
2140 parse_string(dest, ctx, global_argv[i]); /* recursion */
2143 } else switch (ch) {
2145 b_adduint(dest,getpid());
2149 if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2153 b_adduint(dest,last_return_code);
2157 b_adduint(dest,global_argc ? global_argc-1 : 0);
2162 /* XXX maybe someone will try to escape the '}' */
2163 while(ch=b_getch(input),ch!=EOF && ch!='}') {
2170 lookup_param(dest, ctx, &alt);
2174 process_command_subs(dest, ctx, input, ')');
2178 for (i=1; i<global_argc; i++) {
2179 parse_string(dest, ctx, global_argv[i]);
2180 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2186 /* still unhandled, but should be eventually */
2187 fprintf(stderr,"unhandled syntax: $%c\n",ch);
2191 b_addqchr(dest,'$',dest->quote);
2193 /* Eat the character if the flag was set. If the compiler
2194 * is smart enough, we could substitute "b_getch(input);"
2195 * for all the "advance = 1;" above, and also end up with
2196 * a nice size-optimized program. Hah! That'll be the day.
2198 if (advance) b_getch(input);
2202 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2205 setup_string_in_str(&foo, src);
2206 return parse_stream(dest, ctx, &foo, '\0');
2209 /* return code is 0 for normal exit, 1 for syntax error */
2210 int parse_stream(o_string *dest, struct p_context *ctx,
2211 struct in_str *input, int end_trigger)
2215 redir_type redir_style;
2218 /* Only double-quote state is handled in the state variable dest->quote.
2219 * A single-quote triggers a bypass of the main loop until its mate is
2220 * found. When recursing, quote state is passed in via dest->quote. */
2222 debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2223 while ((ch=b_getch(input))!=EOF) {
2225 next = (ch == '\n') ? 0 : b_peek(input);
2226 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2227 ch,ch,m,dest->quote);
2228 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2229 b_addqchr(dest, ch, dest->quote);
2231 if (m==2) { /* unquoted IFS */
2232 done_word(dest, ctx);
2233 /* If we aren't performing a substitution, treat a newline as a
2234 * command separator. */
2235 if (end_trigger != '\0' && ch=='\n')
2236 done_pipe(ctx,PIPE_SEQ);
2238 if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2239 debug_printf("leaving parse_stream\n");
2244 /* Yahoo! Time to run with it! */
2245 done_pipe(ctx,PIPE_SEQ);
2246 run_list(ctx->list_head);
2247 initialize_context(ctx);
2250 if (m!=2) switch (ch) {
2252 if (dest->length == 0 && !dest->quote) {
2253 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2255 b_addqchr(dest, ch, dest->quote);
2263 b_addqchr(dest, '\\', dest->quote);
2264 b_addqchr(dest, b_getch(input), dest->quote);
2267 if (handle_dollar(dest, ctx, input)!=0) return 1;
2271 while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2281 dest->quote = !dest->quote;
2284 process_command_subs(dest, ctx, input, '`');
2287 redir_fd = redirect_opt_num(dest);
2288 done_word(dest, ctx);
2289 redir_style=REDIRECT_OVERWRITE;
2291 redir_style=REDIRECT_APPEND;
2293 } else if (next == '(') {
2294 syntax(); /* until we support >(list) Process Substitution */
2297 setup_redirect(ctx, redir_fd, redir_style, input);
2300 redir_fd = redirect_opt_num(dest);
2301 done_word(dest, ctx);
2302 redir_style=REDIRECT_INPUT;
2304 redir_style=REDIRECT_HEREIS;
2306 } else if (next == '>') {
2307 redir_style=REDIRECT_IO;
2309 } else if (next == '(') {
2310 syntax(); /* until we support <(list) Process Substitution */
2313 setup_redirect(ctx, redir_fd, redir_style, input);
2316 done_word(dest, ctx);
2317 done_pipe(ctx,PIPE_SEQ);
2320 done_word(dest, ctx);
2323 done_pipe(ctx,PIPE_AND);
2325 done_pipe(ctx,PIPE_BG);
2329 done_word(dest, ctx);
2332 done_pipe(ctx,PIPE_OR);
2334 /* we could pick up a file descriptor choice here
2335 * with redirect_opt_num(), but bash doesn't do it.
2336 * "echo foo 2| cat" yields "foo 2". */
2342 if (parse_group(dest, ctx, input, ch)!=0) return 1;
2346 syntax(); /* Proper use of this character caught by end_trigger */
2350 syntax(); /* this is really an internal logic error */
2355 /* complain if quote? No, maybe we just finished a command substitution
2356 * that was quoted. Example:
2357 * $ echo "`cat foo` plus more"
2358 * and we just got the EOF generated by the subshell that ran "cat foo"
2359 * The only real complaint is if we got an EOF when end_trigger != '\0',
2360 * that is, we were really supposed to get end_trigger, and never got
2361 * one before the EOF. Can't use the standard "syntax error" return code,
2362 * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2363 if (end_trigger != '\0') return -1;
2367 void mapset(const unsigned char *set, int code)
2369 const unsigned char *s;
2370 for (s=set; *s; s++) map[*s] = code;
2373 void update_ifs_map(void)
2375 /* char *ifs and char map[256] are both globals. */
2376 ifs = getenv("IFS");
2377 if (ifs == NULL) ifs=" \t\n";
2378 /* Precompute a list of 'flow through' behavior so it can be treated
2379 * quickly up front. Computation is necessary because of IFS.
2380 * Special case handling of IFS == " \t\n" is not implemented.
2381 * The map[] array only really needs two bits each, and on most machines
2382 * that would be faster because of the reduced L1 cache footprint.
2384 memset(map,0,256); /* most characters flow through always */
2385 mapset("\\$'\"`", 3); /* never flow through */
2386 mapset("<>;&|(){}#", 1); /* flow through if quoted */
2387 mapset(ifs, 2); /* also flow through if quoted */
2390 /* most recursion does not come through here, the exeception is
2391 * from builtin_source() */
2392 int parse_stream_outer(struct in_str *inp)
2395 struct p_context ctx;
2396 o_string temp=NULL_O_STRING;
2399 initialize_context(&ctx);
2402 rcode = parse_stream(&temp, &ctx, inp, '\n');
2403 done_word(&temp, &ctx);
2404 done_pipe(&ctx,PIPE_SEQ);
2405 run_list(ctx.list_head);
2406 } while (rcode != -1); /* loop on syntax errors, return on EOF */
2410 static int parse_string_outer(const char *s)
2412 struct in_str input;
2413 setup_string_in_str(&input, s);
2414 return parse_stream_outer(&input);
2417 static int parse_file_outer(FILE *f)
2420 struct in_str input;
2421 setup_file_in_str(&input, f);
2422 rcode = parse_stream_outer(&input);
2426 int shell_main(int argc, char **argv)
2430 struct jobset joblist_end = { NULL, NULL };
2431 job_list = &joblist_end;
2433 last_return_code=EXIT_SUCCESS;
2435 /* XXX what should these be while sourcing /etc/profile? */
2439 /* don't pay any attention to this signal; it just confuses
2440 things and isn't really meant for shells anyway */
2441 signal(SIGTTOU, SIG_IGN);
2443 if (argv[0] && argv[0][0] == '-') {
2444 debug_printf("\nsourcing /etc/profile\n");
2445 input = xfopen("/etc/profile", "r");
2446 mark_open(fileno(input));
2447 parse_file_outer(input);
2448 mark_closed(fileno(input));
2453 /* initialize the cwd -- this is never freed...*/
2457 #ifdef BB_FEATURE_COMMAND_EDITING
2458 cmdedit_set_initial_prompt();
2463 while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2467 global_argv = argv+optind;
2468 global_argc = argc-optind;
2469 opt = parse_string_outer(optarg);
2480 fprintf(stderr, "Usage: sh [FILE]...\n"
2481 " or: sh -c command [args]...\n\n");
2485 /* A shell is interactive if the `-i' flag was given, or if all of
2486 * the following conditions are met:
2488 * no arguments remaining or the -s flag given
2489 * standard input is a terminal
2490 * standard output is a terminal
2491 * Refer to Posix.2, the description of the `sh' utility. */
2492 if (argv[optind]==NULL && input==stdin &&
2493 isatty(fileno(stdin)) && isatty(fileno(stdout))) {
2497 debug_printf("\ninteractive=%d\n", interactive);
2499 /* Looks like they want an interactive shell */
2500 fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n");
2501 opt=parse_file_outer(stdin);
2505 debug_printf("\nrunning script '%s'\n", argv[optind]);
2506 global_argv = argv+optind;
2507 global_argc = argc-optind;
2508 input = xfopen(argv[optind], "r");
2509 opt = parse_file_outer(input);
2511 #ifdef BB_FEATURE_CLEAN_UP
2516 return(opt?opt:last_return_code);