1 /* vi: set sw=4 ts=4: */
3 * sh.c -- a prototype Bourne shell grammar parser
4 * Intended to follow the original Thompson and Ritchie
5 * "small and simple is beautiful" philosophy, which
6 * incidentally is a good match to today's BusyBox.
8 * Copyright (C) 2000,2001 Larry Doolittle <larry@doolittle.boa.org>
11 * The parser routines proper are all original material, first
12 * written Dec 2000 and Jan 2001 by Larry Doolittle.
13 * The execution engine, the builtins, and much of the underlying
14 * support has been adapted from busybox-0.49pre's lash,
15 * which is Copyright (C) 2000 by Lineo, Inc., and
16 * written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>.
17 * That, in turn, is based in part on ladsh.c, by Michael K. Johnson and
18 * Erik W. Troan, which they placed in the public domain. I don't know
19 * how much of the Johnson/Troan code has survived the repeated rewrites.
21 * simple_itoa() was lifted from boa-0.93.15
22 * b_addchr() derived from similar w_addchar function in glibc-2.2
23 * setup_redirect(), redirect_opt_num(), and big chunks of main()
24 * and many builtins derived from contributions by Erik Andersen
25 * miscellaneous bugfixes from Matt Kraai
27 * There are two big (and related) architecture differences between
28 * this parser and the lash parser. One is that this version is
29 * actually designed from the ground up to understand nearly all
30 * of the Bourne grammar. The second, consequential change is that
31 * the parser and input reader have been turned inside out. Now,
32 * the parser is in control, and asks for input as needed. The old
33 * way had the input reader in control, and it asked for parsing to
34 * take place as needed. The new way makes it much easier to properly
35 * handle the recursion implicit in the various substitutions, especially
36 * across continuation lines.
38 * Bash grammar not implemented: (how many of these were in original sh?)
39 * $@ (those sure look like weird quoting rules)
41 * ! negation operator for pipes
42 * &> and >& redirection of stdout+stderr
45 * fancy forms of Parameter Expansion
47 * Arithmetic Expansion
48 * <(list) and >(list) Process Substitution
49 * reserved words: case, esac, select, function
50 * Here Documents ( << word )
53 * job handling woefully incomplete and buggy
54 * reserved word execution woefully incomplete and buggy
56 * port selected bugfixes from post-0.49 busybox lash - done?
57 * finish implementing reserved words: for, while, until, do, done
58 * change { and } from special chars to reserved words
59 * builtins: break, continue, eval, return, set, trap, ulimit
61 * handle children going into background
62 * clean up recognition of null pipes
63 * check setting of global_argc and global_argv
64 * control-C handling, probably with longjmp
65 * follow IFS rules more precisely, including update semantics
66 * figure out what to do with backslash-newline
67 * explain why we use signal instead of sigaction
68 * propagate syntax errors, die on resource errors?
69 * continuation lines, both explicit and implicit - done?
70 * memory leak finding and plugging - done?
71 * more testing, especially quoting rules and redirection
72 * document how quoting rules not precisely followed for variable assignments
73 * maybe change map[] to use 2-bit entries
74 * (eventually) remove all the printf's
76 * This program is free software; you can redistribute it and/or modify
77 * it under the terms of the GNU General Public License as published by
78 * the Free Software Foundation; either version 2 of the License, or
79 * (at your option) any later version.
81 * This program is distributed in the hope that it will be useful,
82 * but WITHOUT ANY WARRANTY; without even the implied warranty of
83 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
84 * General Public License for more details.
86 * You should have received a copy of the GNU General Public License
87 * along with this program; if not, write to the Free Software
88 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
90 #include <ctype.h> /* isalpha, isdigit */
91 #include <unistd.h> /* getpid */
92 #include <stdlib.h> /* getenv, atoi */
93 #include <string.h> /* strchr */
94 #include <stdio.h> /* popen etc. */
95 #include <glob.h> /* glob, of course */
96 #include <stdarg.h> /* va_list */
99 #include <getopt.h> /* should be pretty obvious */
101 #include <sys/stat.h> /* ulimit */
102 #include <sys/types.h>
103 #include <sys/wait.h>
106 /* #include <dmalloc.h> */
107 /* #define DEBUG_SHELL */
113 #define applet_name "hush"
114 #include "standalone.h"
115 #define shell_main main
116 #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 */
243 static char map[256];
244 static int fake_mode;
245 static int interactive;
246 static struct close_me *close_me_head;
247 static const char *cwd;
248 static struct jobset *job_list;
249 static unsigned int last_bg_pid;
252 static char **__shell_local_env;
254 #define B_CHUNK (100)
256 #define MAX_LINE 256 /* for cwd */
257 #define MAX_READ 256 /* for builtin_read */
266 #define NULL_O_STRING {NULL,0,0,0,0}
267 /* used for initialization:
268 o_string foo = NULL_O_STRING; */
270 /* I can almost use ordinary FILE *. Is open_memstream() universally
271 * available? Where is it documented? */
277 int (*get) (struct in_str *);
278 int (*peek) (struct in_str *);
280 #define b_getch(input) ((input)->get(input))
281 #define b_peek(input) ((input)->peek(input))
283 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
285 struct built_in_command {
286 char *cmd; /* name */
287 char *descr; /* description */
288 int (*function) (struct child_prog *); /* function ptr */
291 /* belongs in busybox.h */
292 static inline int max(int a, int b) {
296 /* This should be in utility.c */
298 static void debug_printf(const char *format, ...)
301 va_start(args, format);
302 vfprintf(stderr, format, args);
306 static void debug_printf(const char *format, ...) { }
308 #define final_printf debug_printf
310 void __syntax(char *file, int line) {
311 fprintf(stderr,"syntax error %s:%d\n",file,line);
313 #define syntax() __syntax(__FILE__, __LINE__)
315 /* Index of subroutines: */
316 /* function prototypes for builtins */
317 static int builtin_cd(struct child_prog *child);
318 static int builtin_env(struct child_prog *child);
319 static int builtin_exec(struct child_prog *child);
320 static int builtin_exit(struct child_prog *child);
321 static int builtin_export(struct child_prog *child);
322 static int builtin_fg_bg(struct child_prog *child);
323 static int builtin_help(struct child_prog *child);
324 static int builtin_jobs(struct child_prog *child);
325 static int builtin_pwd(struct child_prog *child);
326 static int builtin_read(struct child_prog *child);
327 static int builtin_set(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);
391 /* local variable support */
392 static char *get_local_var(const char *var);
393 static int set_local_var(const char *s);
394 static void unset_local_var(const char *name);
397 /* Table of built-in functions. They can be forked or not, depending on
398 * context: within pipes, they fork. As simple commands, they do not.
399 * When used in non-forking context, they can change global variables
400 * in the parent shell process. If forked, of course they can not.
401 * For example, 'unset foo | whatever' will parse and run, but foo will
402 * still be set at the end. */
403 static struct built_in_command bltins[] = {
404 {"bg", "Resume a job in the background", builtin_fg_bg},
405 {"break", "Exit for, while or until loop", builtin_not_written},
406 {"cd", "Change working directory", builtin_cd},
407 {"continue", "Continue for, while or until loop", builtin_not_written},
408 {"env", "Print all environment variables", builtin_env},
409 {"eval", "Construct and run shell command", builtin_not_written},
410 {"exec", "Exec command, replacing this shell with the exec'd process",
412 {"exit", "Exit from shell()", builtin_exit},
413 {"export", "Set environment variable", builtin_export},
414 {"fg", "Bring job into the foreground", builtin_fg_bg},
415 {"jobs", "Lists the active jobs", builtin_jobs},
416 {"pwd", "Print current directory", builtin_pwd},
417 {"read", "Input environment variable", builtin_read},
418 {"return", "Return from a function", builtin_not_written},
419 {"set", "Set/unset shell local variables", builtin_set},
420 {"shift", "Shift positional parameters", builtin_shift},
421 {"trap", "Trap signals", builtin_not_written},
422 {"ulimit","Controls resource limits", builtin_not_written},
423 {"umask","Sets file creation mask", builtin_umask},
424 {"unset", "Unset environment variable", builtin_unset},
425 {".", "Source-in and run commands in a file", builtin_source},
426 {"help", "List shell built-in commands", builtin_help},
430 /* built-in 'cd <path>' handler */
431 static int builtin_cd(struct child_prog *child)
434 if (child->argv[1] == NULL)
435 newdir = getenv("HOME");
437 newdir = child->argv[1];
439 printf("cd: %s: %s\n", newdir, strerror(errno));
442 cwd = xgetcwd((char *)cwd);
448 /* built-in 'env' handler */
449 static int builtin_env(struct child_prog *dummy)
452 if (e == NULL) return EXIT_FAILURE;
459 /* built-in 'exec' handler */
460 static int builtin_exec(struct child_prog *child)
462 if (child->argv[1] == NULL)
463 return EXIT_SUCCESS; /* Really? */
469 /* built-in 'exit' handler */
470 static int builtin_exit(struct child_prog *child)
472 if (child->argv[1] == NULL)
473 exit(last_return_code);
474 exit (atoi(child->argv[1]));
477 /* built-in 'export VAR=value' handler */
478 static int builtin_export(struct child_prog *child)
481 char *value, *name = child->argv[1];
484 return (builtin_env(child));
487 value = strchr(name, '=');
489 /* They are exporting something without an =VALUE.
490 * Assume this is a local shell variable they are exporting */
491 name = get_local_var(name);
493 error_msg("export failed");
494 return (EXIT_FAILURE);
496 /* FIXME -- I leak memory!!!!! */
497 value = malloc(strlen(child->argv[1]) + strlen(name) + 2);
498 sprintf(value, "%s=%s", child->argv[1], name);
500 /* Bourne shells always put exported variables into the
501 * local shell variable list. Do that first... */
503 /* FIXME -- I leak memory!!!!! */
504 value = strdup(name);
507 /* FIXME -- I leak memory!!!!!
508 * It seems most putenv implementations place the very char* pointer
509 * we pass in directly into the environ array, so the memory holding
510 * this string has to be persistant. We can't even use the memory for
511 * the local shell variable list, since where that memory is keeps
512 * changing due to reallocs... */
515 perror_msg("export");
519 /* built-in 'fg' and 'bg' handler */
520 static int builtin_fg_bg(struct child_prog *child)
523 struct pipe *pi=NULL;
525 /* If they gave us no args, assume they want the last backgrounded task */
526 if (!child->argv[1]) {
527 for (pi = job_list->head; pi; pi = pi->next) {
528 if (pi->progs && pi->progs->pid == last_bg_pid) {
533 error_msg("%s: no current job", child->argv[0]);
537 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
538 error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
542 for (pi = job_list->head; pi; pi = pi->next) {
543 if (pi->jobid == jobnum) {
548 error_msg("%s: %d: no such job", child->argv[0], jobnum);
552 if (*child->argv[0] == 'f') {
553 /* Make this job the foreground job */
554 signal(SIGTTOU, SIG_IGN);
555 /* suppress messages when run from /linuxrc mag@sysgo.de */
556 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
557 perror_msg("tcsetpgrp");
558 signal(SIGTTOU, SIG_DFL);
562 /* Restart the processes in the job */
563 for (i = 0; i < pi->num_progs; i++)
564 pi->progs[i].is_stopped = 0;
566 kill(-pi->pgrp, SIGCONT);
568 pi->stopped_progs = 0;
572 /* built-in 'help' handler */
573 static int builtin_help(struct child_prog *dummy)
575 struct built_in_command *x;
577 printf("\nBuilt-in commands:\n");
578 printf("-------------------\n");
579 for (x = bltins; x->cmd; x++) {
582 printf("%s\t%s\n", x->cmd, x->descr);
588 /* built-in 'jobs' handler */
589 static int builtin_jobs(struct child_prog *child)
594 for (job = job_list->head; job; job = job->next) {
595 if (job->running_progs == job->stopped_progs)
596 status_string = "Stopped";
598 status_string = "Running";
599 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
605 /* built-in 'pwd' handler */
606 static int builtin_pwd(struct child_prog *dummy)
608 cwd = xgetcwd((char *)cwd);
615 /* built-in 'read VAR' handler */
616 static int builtin_read(struct child_prog *child)
618 int res = 0, len, newlen;
620 char string[MAX_READ];
622 if (child->argv[1]) {
623 /* argument (VAR) given: put "VAR=" into buffer */
624 strcpy(string, child->argv[1]);
625 len = strlen(string);
628 /* XXX would it be better to go through in_str? */
629 fgets(&string[len], sizeof(string) - len, stdin); /* read string */
630 newlen = strlen(string);
632 string[--newlen] = '\0'; /* chomp trailing newline */
634 ** string should now contain "VAR=<value>"
635 ** copy it (putenv() won't do that, so we must make sure
636 ** the string resides in a static buffer!)
639 if((s = strdup(string)))
642 fprintf(stderr, "read: %s\n", strerror(errno));
645 fgets(string, sizeof(string), stdin);
650 /* built-in 'set VAR=value' handler */
651 static int builtin_set(struct child_prog *child)
654 char *temp = child->argv[1];
656 if (child->argv[1] == NULL) {
657 char **e = __shell_local_env;
658 if (e == NULL) return EXIT_FAILURE;
664 res = set_local_var(temp);
666 fprintf(stderr, "set: %s\n", strerror(errno));
671 /* Built-in 'shift' handler */
672 static int builtin_shift(struct child_prog *child)
675 if (child->argv[1]) {
676 n=atoi(child->argv[1]);
678 if (n>=0 && n<global_argc) {
679 /* XXX This probably breaks $0 */
688 /* Built-in '.' handler (read-in and execute commands from file) */
689 static int builtin_source(struct child_prog *child)
694 if (child->argv[1] == NULL)
697 /* XXX search through $PATH is missing */
698 input = fopen(child->argv[1], "r");
700 fprintf(stderr, "Couldn't open file '%s'\n", child->argv[1]);
704 /* Now run the file */
705 /* XXX argv and argc are broken; need to save old global_argv
706 * (pointer only is OK!) on this stack frame,
707 * set global_argv=child->argv+1, recurse, and restore. */
708 mark_open(fileno(input));
709 status = parse_file_outer(input);
710 mark_closed(fileno(input));
715 static int builtin_umask(struct child_prog *child)
718 const char *arg = child->argv[1];
721 new_umask=strtoul(arg, &end, 8);
722 if (*end!='\0' || end == arg) {
726 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
732 /* built-in 'unset VAR' handler */
733 static int builtin_unset(struct child_prog *child)
735 if (child->argv[1] == NULL) {
736 fprintf(stderr, "unset: parameter required.\n");
739 unsetenv(child->argv[1]);
740 unset_local_var(child->argv[1]);
744 static int builtin_not_written(struct child_prog *child)
746 printf("builtin_%s not written\n",child->argv[0]);
750 static int b_check_space(o_string *o, int len)
752 /* It would be easy to drop a more restrictive policy
753 * in here, such as setting a maximum string length */
754 if (o->length + len > o->maxlen) {
755 char *old_data = o->data;
756 /* assert (data == NULL || o->maxlen != 0); */
757 o->maxlen += max(2*len, B_CHUNK);
758 o->data = realloc(o->data, 1 + o->maxlen);
759 if (o->data == NULL) {
763 return o->data == NULL;
766 static int b_addchr(o_string *o, int ch)
768 debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
769 if (b_check_space(o, 1)) return B_NOSPAC;
770 o->data[o->length] = ch;
772 o->data[o->length] = '\0';
776 static void b_reset(o_string *o)
780 if (o->data != NULL) *o->data = '\0';
783 static void b_free(o_string *o)
786 if (o->data != NULL) free(o->data);
791 /* My analysis of quoting semantics tells me that state information
792 * is associated with a destination, not a source.
794 static int b_addqchr(o_string *o, int ch, int quote)
796 if (quote && strchr("*?[\\",ch)) {
798 rc = b_addchr(o, '\\');
801 return b_addchr(o, ch);
804 /* belongs in utility.c */
805 char *simple_itoa(unsigned int i)
807 /* 21 digits plus null terminator, good for 64-bit or smaller ints */
808 static char local[22];
809 char *p = &local[21];
818 static int b_adduint(o_string *o, unsigned int i)
821 char *p = simple_itoa(i);
822 /* no escape checking necessary */
823 do r=b_addchr(o, *p++); while (r==0 && *p);
827 static int static_get(struct in_str *i)
830 if (ch=='\0') return EOF;
834 static int static_peek(struct in_str *i)
839 static inline void cmdedit_set_initial_prompt(void)
841 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
850 static inline void setup_prompt_string(int promptmode, char **prompt_str)
852 debug_printf("setup_prompt_string %d ",promptmode);
853 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
854 /* Set up the prompt */
855 if (promptmode == 1) {
858 PS1=xmalloc(strlen(cwd)+4);
859 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# ");
865 *prompt_str = (promptmode==0)? PS1 : PS2;
867 debug_printf("result %s\n",*prompt_str);
870 static void get_user_input(struct in_str *i)
873 static char the_command[BUFSIZ];
875 setup_prompt_string(i->promptmode, &prompt_str);
876 #ifdef BB_FEATURE_COMMAND_EDITING
878 ** enable command line editing only while a command line
879 ** is actually being read; otherwise, we'll end up bequeathing
880 ** atexit() handlers and other unwanted stuff to our
881 ** child processes (rob@sysgo.de)
883 cmdedit_read_input(prompt_str, the_command);
886 fputs(prompt_str, stdout);
888 the_command[0]=fgetc(i->file);
894 /* This is the magic location that prints prompts
895 * and gets data back from the user */
896 static int file_get(struct in_str *i)
901 /* If there is data waiting, eat it up */
905 /* need to double check i->file because we might be doing something
906 * more complicated by now, like sourcing or substituting. */
907 if (i->__promptme && interactive && i->file == stdin) {
918 debug_printf("b_getch: got a %d\n", ch);
920 if (ch == '\n') i->__promptme=1;
924 /* All the callers guarantee this routine will never be
925 * used right after a newline, so prompting is not needed.
927 static int file_peek(struct in_str *i)
932 static char buffer[2];
933 buffer[0] = fgetc(i->file);
936 debug_printf("b_peek: got a %d\n", *i->p);
941 static void setup_file_in_str(struct in_str *i, FILE *f)
951 static void setup_string_in_str(struct in_str *i, const char *s)
953 i->peek = static_peek;
960 static void mark_open(int fd)
962 struct close_me *new = xmalloc(sizeof(struct close_me));
964 new->next = close_me_head;
968 static void mark_closed(int fd)
970 struct close_me *tmp;
971 if (close_me_head == NULL || close_me_head->fd != fd)
972 error_msg_and_die("corrupt close_me");
974 close_me_head = close_me_head->next;
978 static void close_all()
981 for (c=close_me_head; c; c=c->next) {
984 close_me_head = NULL;
987 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
988 * and stderr if they are redirected. */
989 static int setup_redirects(struct child_prog *prog, int squirrel[])
992 struct redir_struct *redir;
994 for (redir=prog->redirects; redir; redir=redir->next) {
995 if (redir->dup == -1) {
996 mode=redir_table[redir->type].mode;
997 openfd = open(redir->word.gl_pathv[0], mode, 0666);
999 /* this could get lost if stderr has been redirected, but
1000 bash and ash both lose it as well (though zsh doesn't!) */
1001 fprintf(stderr,"error opening %s: %s\n", redir->word.gl_pathv[0],
1006 openfd = redir->dup;
1009 if (openfd != redir->fd) {
1010 if (squirrel && redir->fd < 3) {
1011 squirrel[redir->fd] = dup(redir->fd);
1016 dup2(openfd, redir->fd);
1024 static void restore_redirects(int squirrel[])
1027 for (i=0; i<3; i++) {
1030 /* No error checking. I sure wouldn't know what
1031 * to do with an error if I found one! */
1038 /* XXX this definitely needs some more thought, work, and
1039 * cribbing from other shells */
1040 static int pipe_wait(struct pipe *pi)
1042 int rcode=0, i, pid, running, status;
1043 running = pi->num_progs;
1045 pid=waitpid(-1, &status, 0);
1046 if (pid < 0) perror_msg_and_die("waitpid");
1047 for (i=0; i < pi->num_progs; i++) {
1048 if (pi->progs[i].pid == pid) {
1049 if (i==pi->num_progs-1) rcode=WEXITSTATUS(status);
1050 pi->progs[i].pid = 0;
1059 /* very simple version for testing */
1060 static void pseudo_exec(struct child_prog *child)
1063 struct built_in_command *x;
1065 for (i=0; is_assignment(child->argv[i]); i++) {
1066 putenv(strdup(child->argv[i]));
1068 child->argv+=i; /* XXX this hack isn't so horrible, since we are about
1069 to exit, and therefore don't need to keep data
1070 structures consistent for free() use. */
1071 /* If a variable is assigned in a forest, and nobody listens,
1072 * was it ever really set?
1074 if (child->argv[0] == NULL) exit(EXIT_SUCCESS);
1077 * Check if the command matches any of the builtins.
1078 * Depending on context, this might be redundant. But it's
1079 * easier to waste a few CPU cycles than it is to figure out
1080 * if this is one of those cases.
1082 for (x = bltins; x->cmd; x++) {
1083 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1084 debug_printf("builtin exec %s\n", child->argv[0]);
1085 exit(x->function(child));
1089 /* Check if the command matches any busybox internal commands
1091 * FIXME: This feature is not 100% safe, since
1092 * BusyBox is not fully reentrant, so we have no guarantee the things
1093 * from the .bss are still zeroed, or that things from .data are still
1094 * at their defaults. We could exec ourself from /proc/self/exe, but I
1095 * really dislike relying on /proc for things. We could exec ourself
1096 * from global_argv[0], but if we are in a chroot, we may not be able
1097 * to find ourself... */
1098 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1101 char** argv_l=child->argv;
1102 char *name = child->argv[0];
1104 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1105 /* Following discussions from November 2000 on the busybox mailing
1106 * list, the default configuration, (without
1107 * get_last_path_component()) lets the user force use of an
1108 * external command by specifying the full (with slashes) filename.
1109 * If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then applets
1110 * _aways_ override external commands, so if you want to run
1111 * /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
1112 * filesystem and is _not_ busybox. Some systems may want this,
1114 name = get_last_path_component(name);
1116 /* Count argc for use in a second... */
1117 for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1119 debug_printf("running applet %s\n", name);
1120 run_applet_by_name(name, argc_l, child->argv);
1123 debug_printf("exec of %s\n",child->argv[0]);
1124 execvp(child->argv[0],child->argv);
1127 } else if (child->group) {
1128 debug_printf("runtime nesting to group\n");
1129 interactive=0; /* crucial!!!! */
1130 rcode = run_list_real(child->group);
1131 /* OK to leak memory by not calling run_list_test,
1132 * since this process is about to exit */
1135 /* Can happen. See what bash does with ">foo" by itself. */
1136 debug_printf("trying to pseudo_exec null command\n");
1141 static void insert_bg_job(struct pipe *pi)
1143 struct pipe *thejob;
1145 /* Linear search for the ID of the job to use */
1147 for (thejob = job_list->head; thejob; thejob = thejob->next)
1148 if (thejob->jobid >= pi->jobid)
1149 pi->jobid = thejob->jobid + 1;
1151 /* add thejob to the list of running jobs */
1152 if (!job_list->head) {
1153 thejob = job_list->head = xmalloc(sizeof(*thejob));
1155 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1156 thejob->next = xmalloc(sizeof(*thejob));
1157 thejob = thejob->next;
1160 /* physically copy the struct job */
1161 memcpy(thejob, pi, sizeof(struct pipe));
1162 thejob->next = NULL;
1163 //thejob->num_progs = 0;
1164 thejob->running_progs = thejob->num_progs;
1165 thejob->stopped_progs = 0;
1166 thejob->text = xmalloc(MAX_LINE);
1168 //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1170 char *bar=thejob->text;
1171 char **foo=pi->progs[0].argv;
1172 while(foo && *foo) {
1173 bar += sprintf(bar, "%s ", *foo++);
1177 /* we don't wait for background thejobs to return -- append it
1178 to the list of backgrounded thejobs and leave it alone */
1179 printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1180 last_bg_pid = thejob->progs[0].pid;
1183 /* remove a backgrounded job from a jobset */
1184 static void remove_bg_job(struct pipe *pi)
1186 struct pipe *prev_pipe;
1188 if (pi == job_list->head) {
1189 job_list->head = pi->next;
1191 prev_pipe = job_list->head;
1192 while (prev_pipe->next != pi)
1193 prev_pipe = prev_pipe->next;
1194 prev_pipe->next = pi->next;
1201 /* free up all memory from a pipe */
1202 static void free_pipe(struct pipe *pi)
1206 for (i = 0; i < pi->num_progs; i++) {
1207 free(pi->progs[i].argv);
1208 if (pi->progs[i].redirects)
1209 free(pi->progs[i].redirects);
1217 memset(pi, 0, sizeof(struct pipe));
1221 /* Checks to see if any background processes have exited -- if they
1222 have, figure out why and see if a job has completed */
1223 static void checkjobs()
1230 while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
1231 for (pi = job_list->head; pi; pi = pi->next) {
1233 while (prognum < pi->num_progs &&
1234 pi->progs[prognum].pid != childpid) prognum++;
1235 if (prognum < pi->num_progs)
1239 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1241 pi->running_progs--;
1242 pi->progs[prognum].pid = 0;
1244 if (!pi->running_progs) {
1245 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1252 pi->stopped_progs++;
1253 pi->progs[prognum].is_stopped = 1;
1255 if (pi->stopped_progs == pi->num_progs) {
1256 printf(JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
1261 if (childpid == -1 && errno != ECHILD)
1262 perror_msg("waitpid");
1264 /* move the shell to the foreground */
1265 if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
1266 perror_msg("tcsetpgrp");
1269 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1270 * to finish. See pipe_wait().
1272 * return code is normally -1, when the caller has to wait for children
1273 * to finish to determine the exit status of the pipe. If the pipe
1274 * is a simple builtin command, however, the action is done by the
1275 * time run_pipe_real returns, and the exit code is provided as the
1278 * The input of the pipe is always stdin, the output is always
1279 * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1280 * because it tries to avoid running the command substitution in
1281 * subshell, when that is in fact necessary. The subshell process
1282 * now has its stdout directed to the input of the appropriate pipe,
1283 * so this routine is noticeably simpler.
1285 static int run_pipe_real(struct pipe *pi)
1289 int nextin, nextout;
1290 int pipefds[2]; /* pipefds[0] is for reading */
1291 struct child_prog *child;
1292 struct built_in_command *x;
1298 /* Check if we are supposed to run in the foreground */
1299 if (interactive && pi->followup!=PIPE_BG) {
1300 if ((pi->pgrp = tcgetpgrp(ctty = 2)) < 0
1301 && (pi->pgrp = tcgetpgrp(ctty = 0)) < 0
1302 && (pi->pgrp = tcgetpgrp(ctty = 1)) < 0)
1303 return errno = ENOTTY, -1;
1305 if (pi->pgrp < 0 && pi->pgrp != getpgrp())
1306 return errno = EPERM, -1;
1309 /* Check if this is a simple builtin (not part of a pipe).
1310 * Builtins within pipes have to fork anyway, and are handled in
1311 * pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
1313 if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1314 child = & (pi->progs[0]);
1315 if (child->group && ! child->subshell) {
1316 int squirrel[] = {-1, -1, -1};
1318 debug_printf("non-subshell grouping\n");
1319 setup_redirects(child, squirrel);
1320 /* XXX could we merge code with following builtin case,
1321 * by creating a pseudo builtin that calls run_list_real? */
1322 rcode = run_list_real(child->group);
1323 restore_redirects(squirrel);
1326 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1327 if (i!=0 && child->argv[i]==NULL) {
1328 /* assignments, but no command: set the local environment */
1329 for (i=0; child->argv[i]!=NULL; i++) {
1330 set_local_var(child->argv[i]);
1332 return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */
1334 for (x = bltins; x->cmd; x++) {
1335 if (strcmp(child->argv[i], x->cmd) == 0 ) {
1336 int squirrel[] = {-1, -1, -1};
1338 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1339 debug_printf("magic exec\n");
1340 setup_redirects(child,NULL);
1341 return EXIT_SUCCESS;
1343 debug_printf("builtin inline %s\n", child->argv[0]);
1344 /* XXX setup_redirects acts on file descriptors, not FILEs.
1345 * This is perfect for work that comes after exec().
1346 * Is it really safe for inline use? Experimentally,
1347 * things seem to work with glibc. */
1348 setup_redirects(child, squirrel);
1349 for (i=0; is_assignment(child->argv[i]); i++) {
1350 putenv(strdup(child->argv[i]));
1352 child->argv+=i; /* XXX horrible hack */
1353 rcode = x->function(child);
1354 child->argv-=i; /* XXX restore hack so free() can work right */
1355 restore_redirects(squirrel);
1361 for (i = 0; i < pi->num_progs; i++) {
1362 child = & (pi->progs[i]);
1364 /* pipes are inserted between pairs of commands */
1365 if ((i + 1) < pi->num_progs) {
1366 if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1367 nextout = pipefds[1];
1373 /* XXX test for failed fork()? */
1374 if (!(child->pid = fork())) {
1376 signal(SIGTTOU, SIG_DFL);
1388 if (pipefds[0]!=-1) {
1389 close(pipefds[0]); /* opposite end of our output pipe */
1392 /* Like bash, explicit redirects override pipes,
1393 * and the pipe fd is available for dup'ing. */
1394 setup_redirects(child,NULL);
1396 if (pi->followup!=PIPE_BG) {
1397 /* If we (the child) win the race, put ourselves in the process
1398 * group whose leader is the first process in this pipe. */
1400 pi->pgrp = child->pid;
1402 if (setpgid(0, pi->pgrp) == 0) {
1403 signal(SIGTTOU, SIG_IGN);
1404 tcsetpgrp(ctty, pi->pgrp);
1405 signal(SIGTTOU, SIG_DFL);
1411 /* Put our child in the process group whose leader is the
1412 * first process in this pipe. */
1414 pi->pgrp = child->pid;
1416 /* Don't check for errors. The child may be dead already,
1417 * in which case setpgid returns error code EACCES. */
1418 setpgid(child->pid, pi->pgrp);
1425 /* If there isn't another process, nextin is garbage
1426 but it doesn't matter */
1427 nextin = pipefds[0];
1432 static int run_list_real(struct pipe *pi)
1435 int if_code=0, next_if_code=0; /* need double-buffer to handle elif */
1436 reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1437 for (;pi;pi=pi->next) {
1439 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);
1440 if (rmode == skip_more_in_this_rmode) continue;
1441 skip_more_in_this_rmode = RES_XXXX;
1442 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1443 if (rmode == RES_THEN && if_code) continue;
1444 if (rmode == RES_ELSE && !if_code) continue;
1445 if (rmode == RES_ELIF && !if_code) continue;
1446 if (pi->num_progs == 0) continue;
1447 rcode = run_pipe_real(pi);
1449 /* We only ran a builtin: rcode was set by the return value
1450 * of run_pipe_real(), and we don't need to wait for anything. */
1451 } else if (pi->followup==PIPE_BG) {
1452 /* XXX check bash's behavior with nontrivial pipes */
1453 /* XXX compute jobid */
1454 /* XXX what does bash do with attempts to background builtins? */
1456 rcode = EXIT_SUCCESS;
1460 /* move the new process group into the foreground */
1461 /* suppress messages when run from /linuxrc mag@sysgo.de */
1462 if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY)
1463 perror_msg("tcsetpgrp");
1464 rcode = pipe_wait(pi);
1465 if (tcsetpgrp(0, getpgrp()) && errno != ENOTTY)
1466 perror_msg("tcsetpgrp");
1468 rcode = pipe_wait(pi);
1471 last_return_code=rcode;
1472 if ( rmode == RES_IF || rmode == RES_ELIF )
1473 next_if_code=rcode; /* can be overwritten a number of times */
1474 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1475 (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1476 skip_more_in_this_rmode=rmode;
1482 /* broken, of course, but OK for testing */
1483 static char *indenter(int i)
1485 static char blanks[]=" ";
1486 return &blanks[sizeof(blanks)-i-1];
1489 /* return code is the exit status of the pipe */
1490 static int run_pipe_test(struct pipe *pi, int indent)
1493 struct child_prog *child;
1494 struct redir_struct *r, *rnext;
1495 int a, i, ret_code=0;
1496 char *ind = indenter(indent);
1497 final_printf("%s run pipe: (pid %d)\n",ind,getpid());
1498 for (i=0; i<pi->num_progs; i++) {
1499 child = &pi->progs[i];
1500 final_printf("%s command %d:\n",ind,i);
1502 for (a=0,p=child->argv; *p; a++,p++) {
1503 final_printf("%s argv[%d] = %s\n",ind,a,*p);
1505 globfree(&child->glob_result);
1507 } else if (child->group) {
1508 final_printf("%s begin group (subshell:%d)\n",ind, child->subshell);
1509 ret_code = run_list_test(child->group,indent+3);
1510 final_printf("%s end group\n",ind);
1512 final_printf("%s (nil)\n",ind);
1514 for (r=child->redirects; r; r=rnext) {
1515 final_printf("%s redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
1517 final_printf(" %s\n", *r->word.gl_pathv);
1520 final_printf("&%d\n", r->dup);
1525 child->redirects=NULL;
1527 free(pi->progs); /* children are an array, they get freed all at once */
1532 static int run_list_test(struct pipe *head, int indent)
1534 int rcode=0; /* if list has no members */
1535 struct pipe *pi, *next;
1536 char *ind = indenter(indent);
1537 for (pi=head; pi; pi=next) {
1538 if (pi->num_progs == 0) break;
1539 final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
1540 rcode = run_pipe_test(pi, indent);
1541 final_printf("%s pipe followup code %d\n", ind, pi->followup);
1549 /* Select which version we will use */
1550 static int run_list(struct pipe *pi)
1554 rcode = run_list_real(pi);
1556 /* run_list_test has the side effect of clearing memory
1557 * In the long run that function can be merged with run_list_real,
1558 * but doing that now would hobble the debugging effort. */
1559 run_list_test(pi,0);
1563 /* The API for glob is arguably broken. This routine pushes a non-matching
1564 * string into the output structure, removing non-backslashed backslashes.
1565 * If someone can prove me wrong, by performing this function within the
1566 * original glob(3) api, feel free to rewrite this routine into oblivion.
1567 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1568 * XXX broken if the last character is '\\', check that before calling.
1570 static int globhack(const char *src, int flags, glob_t *pglob)
1575 for (cnt=1, s=src; *s; s++) {
1576 if (*s == '\\') s++;
1580 if (!dest) return GLOB_NOSPACE;
1581 if (!(flags & GLOB_APPEND)) {
1582 pglob->gl_pathv=NULL;
1587 pathc = ++pglob->gl_pathc;
1588 pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1589 if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1590 pglob->gl_pathv[pathc-1]=dest;
1591 pglob->gl_pathv[pathc]=NULL;
1592 for (s=src; *s; s++, dest++) {
1593 if (*s == '\\') s++;
1600 /* XXX broken if the last character is '\\', check that before calling */
1601 static int glob_needed(const char *s)
1604 if (*s == '\\') s++;
1605 if (strchr("*[?",*s)) return 1;
1611 static void globprint(glob_t *pglob)
1614 debug_printf("glob_t at %p:\n", pglob);
1615 debug_printf(" gl_pathc=%d gl_pathv=%p gl_offs=%d gl_flags=%d\n",
1616 pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
1617 for (i=0; i<pglob->gl_pathc; i++)
1618 debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
1619 pglob->gl_pathv[i], pglob->gl_pathv[i]);
1623 static int xglob(o_string *dest, int flags, glob_t *pglob)
1627 /* short-circuit for null word */
1628 /* we can code this better when the debug_printf's are gone */
1629 if (dest->length == 0) {
1630 if (dest->nonnull) {
1631 /* bash man page calls this an "explicit" null */
1632 gr = globhack(dest->data, flags, pglob);
1633 debug_printf("globhack returned %d\n",gr);
1637 } else if (glob_needed(dest->data)) {
1638 gr = glob(dest->data, flags, NULL, pglob);
1639 debug_printf("glob returned %d\n",gr);
1640 if (gr == GLOB_NOMATCH) {
1641 /* quote removal, or more accurately, backslash removal */
1642 gr = globhack(dest->data, flags, pglob);
1643 debug_printf("globhack returned %d\n",gr);
1646 gr = globhack(dest->data, flags, pglob);
1647 debug_printf("globhack returned %d\n",gr);
1649 if (gr == GLOB_NOSPACE) {
1650 fprintf(stderr,"out of memory during glob\n");
1653 if (gr != 0) { /* GLOB_ABORTED ? */
1654 fprintf(stderr,"glob(3) error %d\n",gr);
1656 /* globprint(glob_target); */
1660 /* This is used to get/check local shell variables */
1661 static char *get_local_var(const char *s)
1668 if (!__shell_local_env)
1672 for (p = __shell_local_env; *p; p++) {
1673 if (memcmp(s, *p, len) == 0 && (*p)[len] == '=') {
1674 return *p + len + 1;
1680 /* This is used to set local shell variables */
1681 static int set_local_var(const char *s)
1684 char *tmp,*name, *value;
1692 /* Assume when we enter this function that we are already in
1693 * NAME=VALUE format. So the first order of business is to
1694 * split 's' on the '=' into 'name' and 'value' */
1695 value = strchr(name, '=');
1703 namelen = strlen (name);
1704 vallen = strlen (value);
1706 /* Now see how many local environment entries we have, and check
1707 * if we match an existing environment entry (so we can overwrite it) */
1709 for (ep = __shell_local_env; ep && *ep != NULL; ++ep) {
1710 if (!memcmp (*ep, name, namelen) && (*ep)[namelen] == '=')
1716 if (ep == NULL || *ep == NULL) {
1717 static char **last_environ = NULL;
1718 char **new_environ = (char **) malloc((size + 2) * sizeof(char *));
1719 if (new_environ == NULL) {
1723 memcpy((__ptr_t) new_environ, (__ptr_t) __shell_local_env,
1724 size * sizeof(char *));
1726 new_environ[size] = malloc (namelen + 1 + vallen + 1);
1727 if (new_environ[size] == NULL) {
1733 memcpy (new_environ[size], name, namelen);
1734 new_environ[size][namelen] = '=';
1735 memcpy (&new_environ[size][namelen + 1], value, vallen + 1);
1737 new_environ[size + 1] = NULL;
1739 if (last_environ != NULL)
1740 free ((__ptr_t) last_environ);
1741 last_environ = new_environ;
1742 __shell_local_env = new_environ;
1745 size_t len = strlen (*ep);
1746 if (len < namelen + 1 + vallen) {
1747 char *new = malloc (namelen + 1 + vallen + 1);
1753 memcpy (*ep, name, namelen);
1754 (*ep)[namelen] = '=';
1756 memcpy (&(*ep)[namelen + 1], value, vallen + 1);
1759 /* One last little detail... If this variable is already
1760 * in the environment we must set it there as well... */
1763 /* FIXME -- I leak memory!!!!! */
1772 static void unset_local_var(const char *name)
1779 namelen = strlen(name);
1780 for (dp = ep = __shell_local_env; ep && *ep != NULL; ++ep) {
1781 if (memcmp (*ep, name, namelen)==0 && (*ep)[namelen] == '=') {
1790 static int is_assignment(const char *s)
1792 if (s==NULL || !isalpha(*s)) return 0;
1794 while(isalnum(*s) || *s=='_') ++s;
1798 /* the src parameter allows us to peek forward to a possible &n syntax
1799 * for file descriptor duplication, e.g., "2>&1".
1800 * Return code is 0 normally, 1 if a syntax error is detected in src.
1801 * Resource errors (in xmalloc) cause the process to exit */
1802 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1803 struct in_str *input)
1805 struct child_prog *child=ctx->child;
1806 struct redir_struct *redir = child->redirects;
1807 struct redir_struct *last_redir=NULL;
1809 /* Create a new redir_struct and drop it onto the end of the linked list */
1814 redir = xmalloc(sizeof(struct redir_struct));
1817 last_redir->next=redir;
1819 child->redirects=redir;
1823 redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1825 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1827 /* Check for a '2>&1' type redirect */
1828 redir->dup = redirect_dup_num(input);
1829 if (redir->dup == -2) return 1; /* syntax error */
1830 if (redir->dup != -1) {
1831 /* Erik had a check here that the file descriptor in question
1832 * is legit; I postpone that to "run time"
1833 * A "-" representation of "close me" shows up as a -3 here */
1834 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1836 /* We do _not_ try to open the file that src points to,
1837 * since we need to return and let src be expanded first.
1838 * Set ctx->pending_redirect, so we know what to do at the
1839 * end of the next parsed word.
1841 ctx->pending_redirect = redir;
1846 struct pipe *new_pipe(void) {
1848 pi = xmalloc(sizeof(struct pipe));
1852 pi->followup = 0; /* invalid */
1856 static void initialize_context(struct p_context *ctx)
1859 ctx->pending_redirect=NULL;
1861 ctx->list_head=new_pipe();
1862 ctx->pipe=ctx->list_head;
1865 done_command(ctx); /* creates the memory for working child */
1868 /* normal return is 0
1869 * if a reserved word is found, and processed, return 1
1870 * should handle if, then, elif, else, fi, for, while, until, do, done.
1871 * case, function, and select are obnoxious, save those for later.
1873 int reserved_word(o_string *dest, struct p_context *ctx)
1875 struct reserved_combo {
1880 /* Mostly a list of accepted follow-up reserved words.
1881 * FLAG_END means we are done with the sequence, and are ready
1882 * to turn the compound list into a command.
1883 * FLAG_START means the word must start a new compound list.
1885 static struct reserved_combo reserved_list[] = {
1886 { "if", RES_IF, FLAG_THEN | FLAG_START },
1887 { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
1888 { "elif", RES_ELIF, FLAG_THEN },
1889 { "else", RES_ELSE, FLAG_FI },
1890 { "fi", RES_FI, FLAG_END },
1891 { "for", RES_FOR, FLAG_DO | FLAG_START },
1892 { "while", RES_WHILE, FLAG_DO | FLAG_START },
1893 { "until", RES_UNTIL, FLAG_DO | FLAG_START },
1894 { "do", RES_DO, FLAG_DONE },
1895 { "done", RES_DONE, FLAG_END }
1897 struct reserved_combo *r;
1898 for (r=reserved_list;
1899 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
1900 r<reserved_list+NRES; r++) {
1901 if (strcmp(dest->data, r->literal) == 0) {
1902 debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
1903 if (r->flag & FLAG_START) {
1904 struct p_context *new = xmalloc(sizeof(struct p_context));
1905 debug_printf("push stack\n");
1906 *new = *ctx; /* physical copy */
1907 initialize_context(ctx);
1909 } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
1916 ctx->old_flag = r->flag;
1917 if (ctx->old_flag & FLAG_END) {
1918 struct p_context *old;
1919 debug_printf("pop stack\n");
1921 old->child->group = ctx->list_head;
1922 *ctx = *old; /* physical copy */
1932 /* normal return is 0.
1933 * Syntax or xglob errors return 1. */
1934 static int done_word(o_string *dest, struct p_context *ctx)
1936 struct child_prog *child=ctx->child;
1937 glob_t *glob_target;
1940 debug_printf("done_word: %s %p\n", dest->data, child);
1941 if (dest->length == 0 && !dest->nonnull) {
1942 debug_printf(" true null, ignored\n");
1945 if (ctx->pending_redirect) {
1946 glob_target = &ctx->pending_redirect->word;
1950 return 1; /* syntax error, groups and arglists don't mix */
1953 debug_printf("checking %s for reserved-ness\n",dest->data);
1954 if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
1956 glob_target = &child->glob_result;
1957 if (child->argv) flags |= GLOB_APPEND;
1959 gr = xglob(dest, flags, glob_target);
1960 if (gr != 0) return 1;
1963 if (ctx->pending_redirect) {
1964 ctx->pending_redirect=NULL;
1965 if (glob_target->gl_pathc != 1) {
1966 fprintf(stderr, "ambiguous redirect\n");
1970 child->argv = glob_target->gl_pathv;
1975 /* The only possible error here is out of memory, in which case
1977 static int done_command(struct p_context *ctx)
1979 /* The child is really already in the pipe structure, so
1980 * advance the pipe counter and make a new, null child.
1981 * Only real trickiness here is that the uncommitted
1982 * child structure, to which ctx->child points, is not
1983 * counted in pi->num_progs. */
1984 struct pipe *pi=ctx->pipe;
1985 struct child_prog *prog=ctx->child;
1987 if (prog && prog->group == NULL
1988 && prog->argv == NULL
1989 && prog->redirects == NULL) {
1990 debug_printf("done_command: skipping null command\n");
1994 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
1996 debug_printf("done_command: initializing\n");
1998 pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2000 prog = pi->progs + pi->num_progs;
2001 prog->redirects = NULL;
2003 prog->is_stopped = 0;
2005 prog->glob_result.gl_pathv = NULL;
2009 /* but ctx->pipe and ctx->list_head remain unchanged */
2013 static int done_pipe(struct p_context *ctx, pipe_style type)
2016 done_command(ctx); /* implicit closure of previous command */
2017 debug_printf("done_pipe, type %d\n", type);
2018 ctx->pipe->followup = type;
2019 ctx->pipe->r_mode = ctx->w;
2021 ctx->pipe->next = new_p;
2024 done_command(ctx); /* set up new pipe to accept commands */
2028 /* peek ahead in the in_str to find out if we have a "&n" construct,
2029 * as in "2>&1", that represents duplicating a file descriptor.
2030 * returns either -2 (syntax error), -1 (no &), or the number found.
2032 static int redirect_dup_num(struct in_str *input)
2036 if (ch != '&') return -1;
2038 b_getch(input); /* get the & */
2042 return -3; /* "-" represents "close me" */
2044 while (isdigit(ch)) {
2052 fprintf(stderr, "ambiguous redirect\n");
2056 /* If a redirect is immediately preceded by a number, that number is
2057 * supposed to tell which file descriptor to redirect. This routine
2058 * looks for such preceding numbers. In an ideal world this routine
2059 * needs to handle all the following classes of redirects...
2060 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
2061 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
2062 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
2063 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
2064 * A -1 output from this program means no valid number was found, so the
2065 * caller should use the appropriate default for this redirection.
2067 static int redirect_opt_num(o_string *o)
2071 if (o->length==0) return -1;
2072 for(num=0; num<o->length; num++) {
2073 if (!isdigit(*(o->data+num))) {
2077 /* reuse num (and save an int) */
2083 FILE *generate_stream_from_list(struct pipe *head)
2087 int pid, channel[2];
2088 if (pipe(channel)<0) perror_msg_and_die("pipe");
2091 perror_msg_and_die("fork");
2092 } else if (pid==0) {
2094 if (channel[1] != 1) {
2099 #define SURROGATE "surrogate response"
2100 write(1,SURROGATE,sizeof(SURROGATE));
2101 exit(run_list(head));
2103 exit(run_list_real(head)); /* leaks memory */
2106 debug_printf("forked child %d\n",pid);
2108 pf = fdopen(channel[0],"r");
2109 debug_printf("pipe on FILE *%p\n",pf);
2111 run_list_test(head,0);
2112 pf=popen("echo surrogate response","r");
2113 debug_printf("started fake pipe on FILE *%p\n",pf);
2118 /* this version hacked for testing purposes */
2119 /* return code is exit status of the process that is run. */
2120 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2123 o_string result=NULL_O_STRING;
2124 struct p_context inner;
2126 struct in_str pipe_str;
2127 initialize_context(&inner);
2129 /* recursion to generate command */
2130 retcode = parse_stream(&result, &inner, input, subst_end);
2131 if (retcode != 0) return retcode; /* syntax error or EOF */
2132 done_word(&result, &inner);
2133 done_pipe(&inner, PIPE_SEQ);
2136 p=generate_stream_from_list(inner.list_head);
2137 if (p==NULL) return 1;
2138 mark_open(fileno(p));
2139 setup_file_in_str(&pipe_str, p);
2141 /* now send results of command back into original context */
2142 retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2143 /* XXX In case of a syntax error, should we try to kill the child?
2144 * That would be tough to do right, so just read until EOF. */
2146 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2149 debug_printf("done reading from pipe, pclose()ing\n");
2150 /* This is the step that wait()s for the child. Should be pretty
2151 * safe, since we just read an EOF from its stdout. We could try
2152 * to better, by using wait(), and keeping track of background jobs
2153 * at the same time. That would be a lot of work, and contrary
2154 * to the KISS philosophy of this program. */
2155 mark_closed(fileno(p));
2157 debug_printf("pclosed, retcode=%d\n",retcode);
2158 /* XXX this process fails to trim a single trailing newline */
2162 static int parse_group(o_string *dest, struct p_context *ctx,
2163 struct in_str *input, int ch)
2166 struct p_context sub;
2167 struct child_prog *child = ctx->child;
2170 return 1; /* syntax error, groups and arglists don't mix */
2172 initialize_context(&sub);
2174 case '(': endch=')'; child->subshell=1; break;
2175 case '{': endch='}'; break;
2176 default: syntax(); /* really logic error */
2178 rcode=parse_stream(dest,&sub,input,endch);
2179 done_word(dest,&sub); /* finish off the final word in the subcontext */
2180 done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
2181 child->group = sub.list_head;
2183 /* child remains "open", available for possible redirects */
2186 /* basically useful version until someone wants to get fancier,
2187 * see the bash man page under "Parameter Expansion" */
2188 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src)
2192 p = getenv(src->data);
2194 p = get_local_var(src->data);
2196 if (p) parse_string(dest, ctx, p); /* recursion */
2200 /* return code: 0 for OK, 1 for syntax error */
2201 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2204 o_string alt=NULL_O_STRING;
2206 int ch = input->peek(input); /* first character after the $ */
2207 debug_printf("handle_dollar: ch=%c\n",ch);
2209 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2213 lookup_param(dest, ctx, &alt);
2214 } else if (isdigit(ch)) {
2215 i = ch-'0'; /* XXX is $0 special? */
2216 if (i<global_argc) {
2217 parse_string(dest, ctx, global_argv[i]); /* recursion */
2220 } else switch (ch) {
2222 b_adduint(dest,getpid());
2226 if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2230 b_adduint(dest,last_return_code);
2234 b_adduint(dest,global_argc ? global_argc-1 : 0);
2239 /* XXX maybe someone will try to escape the '}' */
2240 while(ch=b_getch(input),ch!=EOF && ch!='}') {
2247 lookup_param(dest, ctx, &alt);
2251 process_command_subs(dest, ctx, input, ')');
2255 for (i=1; i<global_argc; i++) {
2256 parse_string(dest, ctx, global_argv[i]);
2257 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2263 /* still unhandled, but should be eventually */
2264 fprintf(stderr,"unhandled syntax: $%c\n",ch);
2268 b_addqchr(dest,'$',dest->quote);
2270 /* Eat the character if the flag was set. If the compiler
2271 * is smart enough, we could substitute "b_getch(input);"
2272 * for all the "advance = 1;" above, and also end up with
2273 * a nice size-optimized program. Hah! That'll be the day.
2275 if (advance) b_getch(input);
2279 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2282 setup_string_in_str(&foo, src);
2283 return parse_stream(dest, ctx, &foo, '\0');
2286 /* return code is 0 for normal exit, 1 for syntax error */
2287 int parse_stream(o_string *dest, struct p_context *ctx,
2288 struct in_str *input, int end_trigger)
2292 redir_type redir_style;
2295 /* Only double-quote state is handled in the state variable dest->quote.
2296 * A single-quote triggers a bypass of the main loop until its mate is
2297 * found. When recursing, quote state is passed in via dest->quote. */
2299 debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2300 while ((ch=b_getch(input))!=EOF) {
2302 next = (ch == '\n') ? 0 : b_peek(input);
2303 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2304 ch,ch,m,dest->quote);
2305 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2306 b_addqchr(dest, ch, dest->quote);
2308 if (m==2) { /* unquoted IFS */
2309 done_word(dest, ctx);
2310 /* If we aren't performing a substitution, treat a newline as a
2311 * command separator. */
2312 if (end_trigger != '\0' && ch=='\n')
2313 done_pipe(ctx,PIPE_SEQ);
2315 if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2316 debug_printf("leaving parse_stream\n");
2321 /* Yahoo! Time to run with it! */
2322 done_pipe(ctx,PIPE_SEQ);
2323 run_list(ctx->list_head);
2324 initialize_context(ctx);
2327 if (m!=2) switch (ch) {
2329 if (dest->length == 0 && !dest->quote) {
2330 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2332 b_addqchr(dest, ch, dest->quote);
2340 b_addqchr(dest, '\\', dest->quote);
2341 b_addqchr(dest, b_getch(input), dest->quote);
2344 if (handle_dollar(dest, ctx, input)!=0) return 1;
2348 while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2358 dest->quote = !dest->quote;
2361 process_command_subs(dest, ctx, input, '`');
2364 redir_fd = redirect_opt_num(dest);
2365 done_word(dest, ctx);
2366 redir_style=REDIRECT_OVERWRITE;
2368 redir_style=REDIRECT_APPEND;
2370 } else if (next == '(') {
2371 syntax(); /* until we support >(list) Process Substitution */
2374 setup_redirect(ctx, redir_fd, redir_style, input);
2377 redir_fd = redirect_opt_num(dest);
2378 done_word(dest, ctx);
2379 redir_style=REDIRECT_INPUT;
2381 redir_style=REDIRECT_HEREIS;
2383 } else if (next == '>') {
2384 redir_style=REDIRECT_IO;
2386 } else if (next == '(') {
2387 syntax(); /* until we support <(list) Process Substitution */
2390 setup_redirect(ctx, redir_fd, redir_style, input);
2393 done_word(dest, ctx);
2394 done_pipe(ctx,PIPE_SEQ);
2397 done_word(dest, ctx);
2400 done_pipe(ctx,PIPE_AND);
2402 done_pipe(ctx,PIPE_BG);
2406 done_word(dest, ctx);
2409 done_pipe(ctx,PIPE_OR);
2411 /* we could pick up a file descriptor choice here
2412 * with redirect_opt_num(), but bash doesn't do it.
2413 * "echo foo 2| cat" yields "foo 2". */
2419 if (parse_group(dest, ctx, input, ch)!=0) return 1;
2423 syntax(); /* Proper use of this character caught by end_trigger */
2427 syntax(); /* this is really an internal logic error */
2432 /* complain if quote? No, maybe we just finished a command substitution
2433 * that was quoted. Example:
2434 * $ echo "`cat foo` plus more"
2435 * and we just got the EOF generated by the subshell that ran "cat foo"
2436 * The only real complaint is if we got an EOF when end_trigger != '\0',
2437 * that is, we were really supposed to get end_trigger, and never got
2438 * one before the EOF. Can't use the standard "syntax error" return code,
2439 * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2440 if (end_trigger != '\0') return -1;
2444 void mapset(const unsigned char *set, int code)
2446 const unsigned char *s;
2447 for (s=set; *s; s++) map[*s] = code;
2450 void update_ifs_map(void)
2452 /* char *ifs and char map[256] are both globals. */
2453 ifs = getenv("IFS");
2454 if (ifs == NULL) ifs=" \t\n";
2455 /* Precompute a list of 'flow through' behavior so it can be treated
2456 * quickly up front. Computation is necessary because of IFS.
2457 * Special case handling of IFS == " \t\n" is not implemented.
2458 * The map[] array only really needs two bits each, and on most machines
2459 * that would be faster because of the reduced L1 cache footprint.
2461 memset(map,0,256); /* most characters flow through always */
2462 mapset("\\$'\"`", 3); /* never flow through */
2463 mapset("<>;&|(){}#", 1); /* flow through if quoted */
2464 mapset(ifs, 2); /* also flow through if quoted */
2467 /* most recursion does not come through here, the exeception is
2468 * from builtin_source() */
2469 int parse_stream_outer(struct in_str *inp)
2472 struct p_context ctx;
2473 o_string temp=NULL_O_STRING;
2476 initialize_context(&ctx);
2479 rcode = parse_stream(&temp, &ctx, inp, '\n');
2480 done_word(&temp, &ctx);
2481 done_pipe(&ctx,PIPE_SEQ);
2482 run_list(ctx.list_head);
2483 } while (rcode != -1); /* loop on syntax errors, return on EOF */
2487 static int parse_string_outer(const char *s)
2489 struct in_str input;
2490 setup_string_in_str(&input, s);
2491 return parse_stream_outer(&input);
2494 static int parse_file_outer(FILE *f)
2497 struct in_str input;
2498 setup_file_in_str(&input, f);
2499 rcode = parse_stream_outer(&input);
2503 int shell_main(int argc, char **argv)
2507 struct jobset joblist_end = { NULL, NULL };
2509 /* (re?) initialize globals */
2513 close_me_head = NULL;
2514 job_list = &joblist_end;
2517 __shell_local_env = 0;
2519 last_return_code=EXIT_SUCCESS;
2521 /* XXX what should these be while sourcing /etc/profile? */
2525 /* If we get started under a job aware app (like bash
2526 * for example), make sure we are now in charge so we
2527 * don't fight over who gets the foreground */
2530 initialpgrp = tcgetpgrp(fileno(stderr));
2531 if (initialpgrp < 0) {
2532 error_msg_and_die("sh: can't access tty; job control disabled\n");
2534 if (initialpgrp == -1)
2535 initialpgrp = getpgrp();
2536 else if (initialpgrp != getpgrp()) {
2537 killpg(initialpgrp, SIGTTIN);
2541 /* don't pay any attention to this signal; it just confuses
2542 things and isn't really meant for shells anyway */
2543 signal(SIGTTOU, SIG_IGN);
2544 setpgid(0, getpid());
2545 tcsetpgrp(fileno(stderr), getpid());
2547 if (argv[0] && argv[0][0] == '-') {
2548 debug_printf("\nsourcing /etc/profile\n");
2549 input = xfopen("/etc/profile", "r");
2550 mark_open(fileno(input));
2551 parse_file_outer(input);
2552 mark_closed(fileno(input));
2557 /* initialize the cwd -- this is never freed...*/
2561 #ifdef BB_FEATURE_COMMAND_EDITING
2562 cmdedit_set_initial_prompt();
2567 while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2571 global_argv = argv+optind;
2572 global_argc = argc-optind;
2573 opt = parse_string_outer(optarg);
2584 fprintf(stderr, "Usage: sh [FILE]...\n"
2585 " or: sh -c command [args]...\n\n");
2589 /* A shell is interactive if the `-i' flag was given, or if all of
2590 * the following conditions are met:
2592 * no arguments remaining or the -s flag given
2593 * standard input is a terminal
2594 * standard output is a terminal
2595 * Refer to Posix.2, the description of the `sh' utility. */
2596 if (argv[optind]==NULL && input==stdin &&
2597 isatty(fileno(stdin)) && isatty(fileno(stdout))) {
2601 debug_printf("\ninteractive=%d\n", interactive);
2603 /* Looks like they want an interactive shell */
2604 fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n");
2605 opt=parse_file_outer(stdin);
2609 debug_printf("\nrunning script '%s'\n", argv[optind]);
2610 global_argv = argv+optind;
2611 global_argc = argc-optind;
2612 input = xfopen(argv[optind], "r");
2613 opt = parse_file_outer(input);
2615 #ifdef BB_FEATURE_CLEAN_UP
2620 return(opt?opt:last_return_code);