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 hush_main main
116 #undef CONFIG_FEATURE_SH_FANCY_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 */
223 struct close_me *next;
231 struct variables *next;
234 /* globals, connect us to the outside world
235 * the first three support $?, $#, and $1 */
237 unsigned int global_argc;
238 unsigned int last_return_code;
239 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
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 pipe *job_list;
249 static unsigned int last_bg_pid;
250 static unsigned int last_jobid;
251 static unsigned int shell_terminal;
254 struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
255 struct variables *top_vars = &shell_ver;
258 #define B_CHUNK (100)
268 #define NULL_O_STRING {NULL,0,0,0,0}
269 /* used for initialization:
270 o_string foo = NULL_O_STRING; */
272 /* I can almost use ordinary FILE *. Is open_memstream() universally
273 * available? Where is it documented? */
280 int (*get) (struct in_str *);
281 int (*peek) (struct in_str *);
283 #define b_getch(input) ((input)->get(input))
284 #define b_peek(input) ((input)->peek(input))
286 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
288 struct built_in_command {
289 char *cmd; /* name */
290 char *descr; /* description */
291 int (*function) (struct child_prog *); /* function ptr */
294 /* belongs in busybox.h */
295 static inline int max(int a, int b) {
299 /* This should be in utility.c */
301 static void debug_printf(const char *format, ...)
304 va_start(args, format);
305 vfprintf(stderr, format, args);
309 static inline void debug_printf(const char *format, ...) { }
311 #define final_printf debug_printf
313 static void __syntax(char *file, int line) {
314 error_msg("syntax error %s:%d", file, line);
316 #define syntax() __syntax(__FILE__, __LINE__)
318 /* Index of subroutines: */
319 /* function prototypes for builtins */
320 static int builtin_cd(struct child_prog *child);
321 static int builtin_env(struct child_prog *child);
322 static int builtin_exec(struct child_prog *child);
323 static int builtin_exit(struct child_prog *child);
324 static int builtin_export(struct child_prog *child);
325 static int builtin_fg_bg(struct child_prog *child);
326 static int builtin_help(struct child_prog *child);
327 static int builtin_jobs(struct child_prog *child);
328 static int builtin_pwd(struct child_prog *child);
329 static int builtin_read(struct child_prog *child);
330 static int builtin_set(struct child_prog *child);
331 static int builtin_shift(struct child_prog *child);
332 static int builtin_source(struct child_prog *child);
333 static int builtin_umask(struct child_prog *child);
334 static int builtin_unset(struct child_prog *child);
335 static int builtin_not_written(struct child_prog *child);
336 /* o_string manipulation: */
337 static int b_check_space(o_string *o, int len);
338 static int b_addchr(o_string *o, int ch);
339 static void b_reset(o_string *o);
340 static int b_addqchr(o_string *o, int ch, int quote);
341 static int b_adduint(o_string *o, unsigned int i);
342 /* in_str manipulations: */
343 static int static_get(struct in_str *i);
344 static int static_peek(struct in_str *i);
345 static int file_get(struct in_str *i);
346 static int file_peek(struct in_str *i);
347 static void setup_file_in_str(struct in_str *i, FILE *f);
348 static void setup_string_in_str(struct in_str *i, const char *s);
349 /* close_me manipulations: */
350 static void mark_open(int fd);
351 static void mark_closed(int fd);
352 static void close_all();
353 /* "run" the final data structures: */
354 static char *indenter(int i);
355 static int free_pipe_list(struct pipe *head, int indent);
356 static int free_pipe(struct pipe *pi, int indent);
357 /* really run the final data structures: */
358 static int setup_redirects(struct child_prog *prog, int squirrel[]);
359 static int run_list_real(struct pipe *pi);
360 static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
361 static int run_pipe_real(struct pipe *pi);
362 /* extended glob support: */
363 static int globhack(const char *src, int flags, glob_t *pglob);
364 static int glob_needed(const char *s);
365 static int xglob(o_string *dest, int flags, glob_t *pglob);
366 /* variable assignment: */
367 static int is_assignment(const char *s);
368 /* data structure manipulation: */
369 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
370 static void initialize_context(struct p_context *ctx);
371 static int done_word(o_string *dest, struct p_context *ctx);
372 static int done_command(struct p_context *ctx);
373 static int done_pipe(struct p_context *ctx, pipe_style type);
374 /* primary string parsing: */
375 static int redirect_dup_num(struct in_str *input);
376 static int redirect_opt_num(o_string *o);
377 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
378 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
379 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src);
380 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
381 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
382 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
384 static int parse_stream_outer(struct in_str *inp);
385 static int parse_string_outer(const char *s);
386 static int parse_file_outer(FILE *f);
387 /* job management: */
388 static int checkjobs(struct pipe* fg_pipe);
389 static void insert_bg_job(struct pipe *pi);
390 static void remove_bg_job(struct pipe *pi);
391 /* local variable support */
392 static char *get_local_var(const char *var);
393 static void unset_local_var(const char *name);
394 static int set_local_var(const char *s, int flg_export);
396 /* Table of built-in functions. They can be forked or not, depending on
397 * context: within pipes, they fork. As simple commands, they do not.
398 * When used in non-forking context, they can change global variables
399 * in the parent shell process. If forked, of course they can not.
400 * For example, 'unset foo | whatever' will parse and run, but foo will
401 * still be set at the end. */
402 static struct built_in_command bltins[] = {
403 {"bg", "Resume a job in the background", builtin_fg_bg},
404 {"break", "Exit for, while or until loop", builtin_not_written},
405 {"cd", "Change working directory", builtin_cd},
406 {"continue", "Continue for, while or until loop", builtin_not_written},
407 {"env", "Print all environment variables", builtin_env},
408 {"eval", "Construct and run shell command", builtin_not_written},
409 {"exec", "Exec command, replacing this shell with the exec'd process",
411 {"exit", "Exit from shell()", builtin_exit},
412 {"export", "Set environment variable", builtin_export},
413 {"fg", "Bring job into the foreground", builtin_fg_bg},
414 {"jobs", "Lists the active jobs", builtin_jobs},
415 {"pwd", "Print current directory", builtin_pwd},
416 {"read", "Input environment variable", builtin_read},
417 {"return", "Return from a function", builtin_not_written},
418 {"set", "Set/unset shell local variables", builtin_set},
419 {"shift", "Shift positional parameters", builtin_shift},
420 {"trap", "Trap signals", builtin_not_written},
421 {"ulimit","Controls resource limits", builtin_not_written},
422 {"umask","Sets file creation mask", builtin_umask},
423 {"unset", "Unset environment variable", builtin_unset},
424 {".", "Source-in and run commands in a file", builtin_source},
425 {"help", "List shell built-in commands", builtin_help},
429 static const char *set_cwd(void)
432 cwd = NULL; /* xgetcwd(arg) called free(arg) */
433 cwd = xgetcwd((char *)cwd);
440 /* built-in 'cd <path>' handler */
441 static int builtin_cd(struct child_prog *child)
444 if (child->argv[1] == NULL)
445 newdir = getenv("HOME");
447 newdir = child->argv[1];
449 printf("cd: %s: %s\n", newdir, strerror(errno));
456 /* built-in 'env' handler */
457 static int builtin_env(struct child_prog *dummy)
460 if (e == NULL) return EXIT_FAILURE;
467 /* built-in 'exec' handler */
468 static int builtin_exec(struct child_prog *child)
470 if (child->argv[1] == NULL)
471 return EXIT_SUCCESS; /* Really? */
477 /* built-in 'exit' handler */
478 static int builtin_exit(struct child_prog *child)
480 if (child->argv[1] == NULL)
481 exit(last_return_code);
482 exit (atoi(child->argv[1]));
485 /* built-in 'export VAR=value' handler */
486 static int builtin_export(struct child_prog *child)
489 char *name = child->argv[1];
492 return (builtin_env(child));
498 char *value = strchr(name, '=');
502 /* They are exporting something without an =VALUE */
504 value = get_local_var(name);
506 size_t ln = strlen(name);
508 tmp = realloc(name, ln+strlen(value)+2);
512 sprintf(tmp+ln, "=%s", value);
516 /* bash does not return an error when trying to export
517 * an undefined variable. Do likewise. */
523 perror_msg("export");
525 res = set_local_var(name, 1);
532 /* built-in 'fg' and 'bg' handler */
533 static int builtin_fg_bg(struct child_prog *child)
536 struct pipe *pi=NULL;
540 /* If they gave us no args, assume they want the last backgrounded task */
541 if (!child->argv[1]) {
542 for (pi = job_list; pi; pi = pi->next) {
543 if (pi->jobid == last_jobid) {
548 error_msg("%s: no current job", child->argv[0]);
552 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
553 error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
556 for (pi = job_list; pi; pi = pi->next) {
557 if (pi->jobid == jobnum) {
562 error_msg("%s: %d: no such job", child->argv[0], jobnum);
567 if (*child->argv[0] == 'f') {
568 /* Put the job into the foreground. */
569 tcsetpgrp(shell_terminal, pi->pgrp);
572 /* Restart the processes in the job */
573 for (i = 0; i < pi->num_progs; i++)
574 pi->progs[i].is_stopped = 0;
576 if ( (i=kill(- pi->pgrp, SIGCONT)) < 0) {
580 perror_msg("kill (SIGCONT)");
584 pi->stopped_progs = 0;
588 /* built-in 'help' handler */
589 static int builtin_help(struct child_prog *dummy)
591 struct built_in_command *x;
593 printf("\nBuilt-in commands:\n");
594 printf("-------------------\n");
595 for (x = bltins; x->cmd; x++) {
598 printf("%s\t%s\n", x->cmd, x->descr);
604 /* built-in 'jobs' handler */
605 static int builtin_jobs(struct child_prog *child)
610 for (job = job_list; job; job = job->next) {
611 if (job->running_progs == job->stopped_progs)
612 status_string = "Stopped";
614 status_string = "Running";
616 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
622 /* built-in 'pwd' handler */
623 static int builtin_pwd(struct child_prog *dummy)
629 /* built-in 'read VAR' handler */
630 static int builtin_read(struct child_prog *child)
634 if (child->argv[1]) {
638 string[0] = 0; /* In case stdin has only EOF */
640 fgets(string, sizeof(string), stdin);
642 var = malloc(strlen(child->argv[1])+strlen(string)+2);
644 sprintf(var, "%s=%s", child->argv[1], string);
645 res = set_local_var(var, 0);
649 fprintf(stderr, "read: %m\n");
650 free(var); /* So not move up to avoid breaking errno */
653 do res=getchar(); while(res!='\n' && res!=EOF);
658 /* built-in 'set VAR=value' handler */
659 static int builtin_set(struct child_prog *child)
661 char *temp = child->argv[1];
665 for(e = top_vars; e; e=e->next)
666 printf("%s=%s\n", e->name, e->value);
668 set_local_var(temp, 0);
674 /* Built-in 'shift' handler */
675 static int builtin_shift(struct child_prog *child)
678 if (child->argv[1]) {
679 n=atoi(child->argv[1]);
681 if (n>=0 && n<global_argc) {
682 /* XXX This probably breaks $0 */
691 /* Built-in '.' handler (read-in and execute commands from file) */
692 static int builtin_source(struct child_prog *child)
697 if (child->argv[1] == NULL)
700 /* XXX search through $PATH is missing */
701 input = fopen(child->argv[1], "r");
703 error_msg("Couldn't open file '%s'", child->argv[1]);
707 /* Now run the file */
708 /* XXX argv and argc are broken; need to save old global_argv
709 * (pointer only is OK!) on this stack frame,
710 * set global_argv=child->argv+1, recurse, and restore. */
711 mark_open(fileno(input));
712 status = parse_file_outer(input);
713 mark_closed(fileno(input));
718 static int builtin_umask(struct child_prog *child)
721 const char *arg = child->argv[1];
724 new_umask=strtoul(arg, &end, 8);
725 if (*end!='\0' || end == arg) {
729 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
735 /* built-in 'unset VAR' handler */
736 static int builtin_unset(struct child_prog *child)
738 /* bash returned already true */
739 unset_local_var(child->argv[1]);
743 static int builtin_not_written(struct child_prog *child)
745 printf("builtin_%s not written\n",child->argv[0]);
749 static int b_check_space(o_string *o, int len)
751 /* It would be easy to drop a more restrictive policy
752 * in here, such as setting a maximum string length */
753 if (o->length + len > o->maxlen) {
754 char *old_data = o->data;
755 /* assert (data == NULL || o->maxlen != 0); */
756 o->maxlen += max(2*len, B_CHUNK);
757 o->data = realloc(o->data, 1 + o->maxlen);
758 if (o->data == NULL) {
762 return o->data == NULL;
765 static int b_addchr(o_string *o, int ch)
767 debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
768 if (b_check_space(o, 1)) return B_NOSPAC;
769 o->data[o->length] = ch;
771 o->data[o->length] = '\0';
775 static void b_reset(o_string *o)
779 if (o->data != NULL) *o->data = '\0';
782 static void b_free(o_string *o)
785 if (o->data != NULL) free(o->data);
790 /* My analysis of quoting semantics tells me that state information
791 * is associated with a destination, not a source.
793 static int b_addqchr(o_string *o, int ch, int quote)
795 if (quote && strchr("*?[\\",ch)) {
797 rc = b_addchr(o, '\\');
800 return b_addchr(o, ch);
803 /* belongs in utility.c */
804 char *simple_itoa(unsigned int i)
806 /* 21 digits plus null terminator, good for 64-bit or smaller ints */
807 static char local[22];
808 char *p = &local[21];
817 static int b_adduint(o_string *o, unsigned int i)
820 char *p = simple_itoa(i);
821 /* no escape checking necessary */
822 do r=b_addchr(o, *p++); while (r==0 && *p);
826 static int static_get(struct in_str *i)
829 if (ch=='\0') return EOF;
833 static int static_peek(struct in_str *i)
838 static inline void cmdedit_set_initial_prompt(void)
840 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
849 static inline void setup_prompt_string(int promptmode, char **prompt_str)
851 debug_printf("setup_prompt_string %d ",promptmode);
852 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
853 /* Set up the prompt */
854 if (promptmode == 1) {
857 PS1=xmalloc(strlen(cwd)+4);
858 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# ");
864 *prompt_str = (promptmode==1)? PS1 : PS2;
866 debug_printf("result %s\n",*prompt_str);
869 static void get_user_input(struct in_str *i)
872 static char the_command[BUFSIZ];
874 setup_prompt_string(i->promptmode, &prompt_str);
875 #ifdef CONFIG_FEATURE_COMMAND_EDITING
877 ** enable command line editing only while a command line
878 ** is actually being read; otherwise, we'll end up bequeathing
879 ** atexit() handlers and other unwanted stuff to our
880 ** child processes (rob@sysgo.de)
882 cmdedit_read_input(prompt_str, the_command);
884 fputs(prompt_str, stdout);
886 the_command[0]=fgetc(i->file);
893 /* This is the magic location that prints prompts
894 * and gets data back from the user */
895 static int file_get(struct in_str *i)
900 /* If there is data waiting, eat it up */
904 /* need to double check i->file because we might be doing something
905 * more complicated by now, like sourcing or substituting. */
906 if (i->__promptme && interactive && i->file == stdin) {
907 while(! i->p || (interactive && strlen(i->p)==0) ) {
919 debug_printf("b_getch: got a %d\n", ch);
921 if (ch == '\n') i->__promptme=1;
925 /* All the callers guarantee this routine will never be
926 * used right after a newline, so prompting is not needed.
928 static int file_peek(struct in_str *i)
933 i->peek_buf[0] = fgetc(i->file);
934 i->peek_buf[1] = '\0';
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 && redir->word.gl_pathv == NULL) {
996 /* something went wrong in the parse. Pretend it didn't happen */
999 if (redir->dup == -1) {
1000 mode=redir_table[redir->type].mode;
1001 openfd = open(redir->word.gl_pathv[0], mode, 0666);
1003 /* this could get lost if stderr has been redirected, but
1004 bash and ash both lose it as well (though zsh doesn't!) */
1005 perror_msg("error opening %s", redir->word.gl_pathv[0]);
1009 openfd = redir->dup;
1012 if (openfd != redir->fd) {
1013 if (squirrel && redir->fd < 3) {
1014 squirrel[redir->fd] = dup(redir->fd);
1019 dup2(openfd, redir->fd);
1020 if (redir->dup == -1)
1028 static void restore_redirects(int squirrel[])
1031 for (i=0; i<3; i++) {
1034 /* No error checking. I sure wouldn't know what
1035 * to do with an error if I found one! */
1043 /* XXX no exit() here. If you don't exec, use _exit instead.
1044 * The at_exit handlers apparently confuse the calling process,
1045 * in particular stdin handling. Not sure why? */
1046 static void pseudo_exec(struct child_prog *child)
1049 struct built_in_command *x;
1051 for (i=0; is_assignment(child->argv[i]); i++) {
1052 debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
1053 putenv(strdup(child->argv[i]));
1055 child->argv+=i; /* XXX this hack isn't so horrible, since we are about
1056 to exit, and therefore don't need to keep data
1057 structures consistent for free() use. */
1058 /* If a variable is assigned in a forest, and nobody listens,
1059 * was it ever really set?
1061 if (child->argv[0] == NULL) {
1062 _exit(EXIT_SUCCESS);
1066 * Check if the command matches any of the builtins.
1067 * Depending on context, this might be redundant. But it's
1068 * easier to waste a few CPU cycles than it is to figure out
1069 * if this is one of those cases.
1071 for (x = bltins; x->cmd; x++) {
1072 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1073 debug_printf("builtin exec %s\n", child->argv[0]);
1074 rcode = x->function(child);
1080 /* Check if the command matches any busybox internal commands
1082 * FIXME: This feature is not 100% safe, since
1083 * BusyBox is not fully reentrant, so we have no guarantee the things
1084 * from the .bss are still zeroed, or that things from .data are still
1085 * at their defaults. We could exec ourself from /proc/self/exe, but I
1086 * really dislike relying on /proc for things. We could exec ourself
1087 * from global_argv[0], but if we are in a chroot, we may not be able
1088 * to find ourself... */
1089 #ifdef CONFIG_FEATURE_SH_STANDALONE_SHELL
1092 char** argv_l=child->argv;
1093 char *name = child->argv[0];
1095 #ifdef CONFIG_FEATURE_SH_APPLETS_ALWAYS_WIN
1096 /* Following discussions from November 2000 on the busybox mailing
1097 * list, the default configuration, (without
1098 * get_last_path_component()) lets the user force use of an
1099 * external command by specifying the full (with slashes) filename.
1100 * If you enable CONFIG_FEATURE_SH_APPLETS_ALWAYS_WIN, then applets
1101 * _aways_ override external commands, so if you want to run
1102 * /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
1103 * filesystem and is _not_ busybox. Some systems may want this,
1105 name = get_last_path_component(name);
1107 /* Count argc for use in a second... */
1108 for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1110 debug_printf("running applet %s\n", name);
1111 run_applet_by_name(name, argc_l, child->argv);
1114 debug_printf("exec of %s\n",child->argv[0]);
1115 execvp(child->argv[0],child->argv);
1116 perror_msg("couldn't exec: %s",child->argv[0]);
1118 } else if (child->group) {
1119 debug_printf("runtime nesting to group\n");
1120 interactive=0; /* crucial!!!! */
1121 rcode = run_list_real(child->group);
1122 /* OK to leak memory by not calling free_pipe_list,
1123 * since this process is about to exit */
1126 /* Can happen. See what bash does with ">foo" by itself. */
1127 debug_printf("trying to pseudo_exec null command\n");
1128 _exit(EXIT_SUCCESS);
1132 static void insert_bg_job(struct pipe *pi)
1134 struct pipe *thejob;
1136 /* Linear search for the ID of the job to use */
1138 for (thejob = job_list; thejob; thejob = thejob->next)
1139 if (thejob->jobid >= pi->jobid)
1140 pi->jobid = thejob->jobid + 1;
1142 /* add thejob to the list of running jobs */
1144 thejob = job_list = xmalloc(sizeof(*thejob));
1146 for (thejob = job_list; thejob->next; thejob = thejob->next) /* nothing */;
1147 thejob->next = xmalloc(sizeof(*thejob));
1148 thejob = thejob->next;
1151 /* physically copy the struct job */
1152 memcpy(thejob, pi, sizeof(struct pipe));
1153 thejob->next = NULL;
1154 thejob->running_progs = thejob->num_progs;
1155 thejob->stopped_progs = 0;
1156 thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
1158 //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1160 char *bar=thejob->text;
1161 char **foo=pi->progs[0].argv;
1162 while(foo && *foo) {
1163 bar += sprintf(bar, "%s ", *foo++);
1167 /* we don't wait for background thejobs to return -- append it
1168 to the list of backgrounded thejobs and leave it alone */
1169 printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1170 last_bg_pid = thejob->progs[0].pid;
1171 last_jobid = thejob->jobid;
1174 /* remove a backgrounded job */
1175 static void remove_bg_job(struct pipe *pi)
1177 struct pipe *prev_pipe;
1179 if (pi == job_list) {
1180 job_list = pi->next;
1182 prev_pipe = job_list;
1183 while (prev_pipe->next != pi)
1184 prev_pipe = prev_pipe->next;
1185 prev_pipe->next = pi->next;
1188 last_jobid = job_list->jobid;
1192 pi->stopped_progs = 0;
1197 /* Checks to see if any processes have exited -- if they
1198 have, figure out why and see if a job has completed */
1199 static int checkjobs(struct pipe* fg_pipe)
1207 attributes = WUNTRACED;
1208 if (fg_pipe==NULL) {
1209 attributes |= WNOHANG;
1212 while ((childpid = waitpid(-1, &status, attributes)) > 0) {
1215 for (i=0; i < fg_pipe->num_progs; i++) {
1216 if (fg_pipe->progs[i].pid == childpid) {
1217 if (i==fg_pipe->num_progs-1)
1218 rcode=WEXITSTATUS(status);
1219 (fg_pipe->num_progs)--;
1225 for (pi = job_list; pi; pi = pi->next) {
1227 while (prognum < pi->num_progs && pi->progs[prognum].pid != childpid) {
1230 if (prognum < pi->num_progs)
1235 debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
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);
1250 pi->stopped_progs++;
1251 pi->progs[prognum].is_stopped = 1;
1254 /* Printing this stuff is a pain, since it tends to
1255 * overwrite the prompt an inconveinient moments. So
1257 if (pi->stopped_progs == pi->num_progs) {
1258 printf("\n"JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
1264 if (childpid == -1 && errno != ECHILD)
1265 perror_msg("waitpid");
1267 /* move the shell to the foreground */
1268 //if (interactive && tcsetpgrp(shell_terminal, getpgid(0)))
1269 // perror_msg("tcsetpgrp-2");
1273 /* Figure out our controlling tty, checking in order stderr,
1274 * stdin, and stdout. If check_pgrp is set, also check that
1275 * we belong to the foreground process group associated with
1276 * that tty. The value of shell_terminal is needed in order to call
1277 * tcsetpgrp(shell_terminal, ...); */
1278 void controlling_tty(int check_pgrp)
1282 if ((curpgrp = tcgetpgrp(shell_terminal = 2)) < 0
1283 && (curpgrp = tcgetpgrp(shell_terminal = 0)) < 0
1284 && (curpgrp = tcgetpgrp(shell_terminal = 1)) < 0)
1285 goto shell_terminal_error;
1287 if (check_pgrp && curpgrp != getpgid(0))
1288 goto shell_terminal_error;
1292 shell_terminal_error:
1293 shell_terminal = -1;
1297 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1298 * to finish. See checkjobs().
1300 * return code is normally -1, when the caller has to wait for children
1301 * to finish to determine the exit status of the pipe. If the pipe
1302 * is a simple builtin command, however, the action is done by the
1303 * time run_pipe_real returns, and the exit code is provided as the
1306 * The input of the pipe is always stdin, the output is always
1307 * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1308 * because it tries to avoid running the command substitution in
1309 * subshell, when that is in fact necessary. The subshell process
1310 * now has its stdout directed to the input of the appropriate pipe,
1311 * so this routine is noticeably simpler.
1313 static int run_pipe_real(struct pipe *pi)
1316 int nextin, nextout;
1317 int pipefds[2]; /* pipefds[0] is for reading */
1318 struct child_prog *child;
1319 struct built_in_command *x;
1324 /* Check if this is a simple builtin (not part of a pipe).
1325 * Builtins within pipes have to fork anyway, and are handled in
1326 * pseudo_exec. "echo foo | read bar" doesn't work on bash, either.
1328 if (pi->num_progs == 1) child = & (pi->progs[0]);
1329 if (pi->num_progs == 1 && child->group && child->subshell == 0) {
1330 int squirrel[] = {-1, -1, -1};
1332 debug_printf("non-subshell grouping\n");
1333 setup_redirects(child, squirrel);
1334 /* XXX could we merge code with following builtin case,
1335 * by creating a pseudo builtin that calls run_list_real? */
1336 rcode = run_list_real(child->group);
1337 restore_redirects(squirrel);
1339 } else if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1340 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1341 if (i!=0 && child->argv[i]==NULL) {
1342 /* assignments, but no command: set the local environment */
1343 for (i=0; child->argv[i]!=NULL; i++) {
1345 /* Ok, this case is tricky. We have to decide if this is a
1346 * local variable, or an already exported variable. If it is
1347 * already exported, we have to export the new value. If it is
1348 * not exported, we need only set this as a local variable.
1349 * This junk is all to decide whether or not to export this
1353 name = xstrdup(child->argv[i]);
1354 debug_printf("Local environment set: %s\n", name);
1355 value = strchr(name, '=');
1358 if ( get_local_var(name)) {
1362 set_local_var(child->argv[i], export_me);
1364 return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */
1366 for (x = bltins; x->cmd; x++) {
1367 if (strcmp(child->argv[i], x->cmd) == 0 ) {
1368 int squirrel[] = {-1, -1, -1};
1370 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1371 debug_printf("magic exec\n");
1372 setup_redirects(child,NULL);
1373 return EXIT_SUCCESS;
1375 debug_printf("builtin inline %s\n", child->argv[0]);
1376 /* XXX setup_redirects acts on file descriptors, not FILEs.
1377 * This is perfect for work that comes after exec().
1378 * Is it really safe for inline use? Experimentally,
1379 * things seem to work with glibc. */
1380 setup_redirects(child, squirrel);
1381 for (i=0; is_assignment(child->argv[i]); i++) {
1382 putenv(strdup(child->argv[i]));
1384 child->argv+=i; /* XXX horrible hack */
1385 rcode = x->function(child);
1386 child->argv-=i; /* XXX restore hack so free() can work right */
1387 restore_redirects(squirrel);
1393 for (i = 0; i < pi->num_progs; i++) {
1394 child = & (pi->progs[i]);
1396 /* pipes are inserted between pairs of commands */
1397 if ((i + 1) < pi->num_progs) {
1398 if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1399 nextout = pipefds[1];
1405 /* XXX test for failed fork()? */
1406 if (!(child->pid = fork())) {
1407 /* Set the handling for job control signals back to the default. */
1408 signal(SIGINT, SIG_DFL);
1409 signal(SIGQUIT, SIG_DFL);
1410 signal(SIGTERM, SIG_DFL);
1411 signal(SIGTSTP, SIG_DFL);
1412 signal(SIGTTIN, SIG_DFL);
1413 signal(SIGTTOU, SIG_DFL);
1414 signal(SIGCHLD, SIG_DFL);
1426 if (pipefds[0]!=-1) {
1427 close(pipefds[0]); /* opposite end of our output pipe */
1430 /* Like bash, explicit redirects override pipes,
1431 * and the pipe fd is available for dup'ing. */
1432 setup_redirects(child,NULL);
1434 if (interactive && pi->followup!=PIPE_BG) {
1435 /* If we (the child) win the race, put ourselves in the process
1436 * group whose leader is the first process in this pipe. */
1438 pi->pgrp = getpid();
1440 if (setpgid(0, pi->pgrp) == 0) {
1441 tcsetpgrp(2, pi->pgrp);
1449 /* put our child in the process group whose leader is the
1450 first process in this pipe */
1452 pi->pgrp = child->pid;
1454 /* Don't check for errors. The child may be dead already,
1455 * in which case setpgid returns error code EACCES. */
1456 setpgid(child->pid, pi->pgrp);
1463 /* If there isn't another process, nextin is garbage
1464 but it doesn't matter */
1465 nextin = pipefds[0];
1470 static int run_list_real(struct pipe *pi)
1473 int if_code=0, next_if_code=0; /* need double-buffer to handle elif */
1474 reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1475 for (;pi;pi=pi->next) {
1477 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);
1478 if (rmode == skip_more_in_this_rmode) continue;
1479 skip_more_in_this_rmode = RES_XXXX;
1480 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1481 if (rmode == RES_THEN && if_code) continue;
1482 if (rmode == RES_ELSE && !if_code) continue;
1483 if (rmode == RES_ELIF && !if_code) continue;
1484 if (pi->num_progs == 0) continue;
1485 rcode = run_pipe_real(pi);
1486 debug_printf("run_pipe_real returned %d\n",rcode);
1488 /* We only ran a builtin: rcode was set by the return value
1489 * of run_pipe_real(), and we don't need to wait for anything. */
1490 } else if (pi->followup==PIPE_BG) {
1491 /* XXX check bash's behavior with nontrivial pipes */
1492 /* XXX compute jobid */
1493 /* XXX what does bash do with attempts to background builtins? */
1495 rcode = EXIT_SUCCESS;
1498 /* move the new process group into the foreground */
1499 if (tcsetpgrp(shell_terminal, pi->pgrp) && errno != ENOTTY)
1500 perror_msg("tcsetpgrp-3");
1501 rcode = checkjobs(pi);
1502 /* move the shell to the foreground */
1503 if (tcsetpgrp(shell_terminal, getpgid(0)) && errno != ENOTTY)
1504 perror_msg("tcsetpgrp-4");
1506 rcode = checkjobs(pi);
1508 debug_printf("checkjobs returned %d\n",rcode);
1510 last_return_code=rcode;
1511 if ( rmode == RES_IF || rmode == RES_ELIF )
1512 next_if_code=rcode; /* can be overwritten a number of times */
1513 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1514 (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1515 skip_more_in_this_rmode=rmode;
1521 /* broken, of course, but OK for testing */
1522 static char *indenter(int i)
1524 static char blanks[]=" ";
1525 return &blanks[sizeof(blanks)-i-1];
1528 /* return code is the exit status of the pipe */
1529 static int free_pipe(struct pipe *pi, int indent)
1532 struct child_prog *child;
1533 struct redir_struct *r, *rnext;
1534 int a, i, ret_code=0;
1535 char *ind = indenter(indent);
1537 if (pi->stopped_progs > 0)
1539 final_printf("%s run pipe: (pid %d)\n",ind,getpid());
1540 for (i=0; i<pi->num_progs; i++) {
1541 child = &pi->progs[i];
1542 final_printf("%s command %d:\n",ind,i);
1544 for (a=0,p=child->argv; *p; a++,p++) {
1545 final_printf("%s argv[%d] = %s\n",ind,a,*p);
1547 globfree(&child->glob_result);
1549 } else if (child->group) {
1550 final_printf("%s begin group (subshell:%d)\n",ind, child->subshell);
1551 ret_code = free_pipe_list(child->group,indent+3);
1552 final_printf("%s end group\n",ind);
1554 final_printf("%s (nil)\n",ind);
1556 for (r=child->redirects; r; r=rnext) {
1557 final_printf("%s redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
1559 /* guard against the case >$FOO, where foo is unset or blank */
1560 if (r->word.gl_pathv) {
1561 final_printf(" %s\n", *r->word.gl_pathv);
1565 final_printf("&%d\n", r->dup);
1570 child->redirects=NULL;
1572 free(pi->progs); /* children are an array, they get freed all at once */
1577 static int free_pipe_list(struct pipe *head, int indent)
1579 int rcode=0; /* if list has no members */
1580 struct pipe *pi, *next;
1581 char *ind = indenter(indent);
1582 for (pi=head; pi; pi=next) {
1583 final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
1584 rcode = free_pipe(pi, indent);
1585 final_printf("%s pipe followup code %d\n", ind, pi->followup);
1593 /* Select which version we will use */
1594 static int run_list(struct pipe *pi)
1598 rcode = run_list_real(pi);
1600 /* free_pipe_list has the side effect of clearing memory
1601 * In the long run that function can be merged with run_list_real,
1602 * but doing that now would hobble the debugging effort. */
1603 free_pipe_list(pi,0);
1607 /* The API for glob is arguably broken. This routine pushes a non-matching
1608 * string into the output structure, removing non-backslashed backslashes.
1609 * If someone can prove me wrong, by performing this function within the
1610 * original glob(3) api, feel free to rewrite this routine into oblivion.
1611 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1612 * XXX broken if the last character is '\\', check that before calling.
1614 static int globhack(const char *src, int flags, glob_t *pglob)
1619 for (cnt=1, s=src; s && *s; s++) {
1620 if (*s == '\\') s++;
1624 if (!dest) return GLOB_NOSPACE;
1625 if (!(flags & GLOB_APPEND)) {
1626 pglob->gl_pathv=NULL;
1631 pathc = ++pglob->gl_pathc;
1632 pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1633 if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1634 pglob->gl_pathv[pathc-1]=dest;
1635 pglob->gl_pathv[pathc]=NULL;
1636 for (s=src; s && *s; s++, dest++) {
1637 if (*s == '\\') s++;
1644 /* XXX broken if the last character is '\\', check that before calling */
1645 static int glob_needed(const char *s)
1648 if (*s == '\\') s++;
1649 if (strchr("*[?",*s)) return 1;
1655 static void globprint(glob_t *pglob)
1658 debug_printf("glob_t at %p:\n", pglob);
1659 debug_printf(" gl_pathc=%d gl_pathv=%p gl_offs=%d gl_flags=%d\n",
1660 pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
1661 for (i=0; i<pglob->gl_pathc; i++)
1662 debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
1663 pglob->gl_pathv[i], pglob->gl_pathv[i]);
1667 static int xglob(o_string *dest, int flags, glob_t *pglob)
1671 /* short-circuit for null word */
1672 /* we can code this better when the debug_printf's are gone */
1673 if (dest->length == 0) {
1674 if (dest->nonnull) {
1675 /* bash man page calls this an "explicit" null */
1676 gr = globhack(dest->data, flags, pglob);
1677 debug_printf("globhack returned %d\n",gr);
1681 } else if (glob_needed(dest->data)) {
1682 gr = glob(dest->data, flags, NULL, pglob);
1683 debug_printf("glob returned %d\n",gr);
1684 if (gr == GLOB_NOMATCH) {
1685 /* quote removal, or more accurately, backslash removal */
1686 gr = globhack(dest->data, flags, pglob);
1687 debug_printf("globhack returned %d\n",gr);
1690 gr = globhack(dest->data, flags, pglob);
1691 debug_printf("globhack returned %d\n",gr);
1693 if (gr == GLOB_NOSPACE)
1694 error_msg_and_die("out of memory during glob");
1695 if (gr != 0) { /* GLOB_ABORTED ? */
1696 error_msg("glob(3) error %d",gr);
1698 /* globprint(glob_target); */
1702 /* This is used to get/check local shell variables */
1703 static char *get_local_var(const char *s)
1705 struct variables *cur;
1709 for (cur = top_vars; cur; cur=cur->next)
1710 if(strcmp(cur->name, s)==0)
1715 /* This is used to set local shell variables
1716 flg_export==0 if only local (not exporting) variable
1717 flg_export==1 if "new" exporting environ
1718 flg_export>1 if current startup environ (not call putenv()) */
1719 static int set_local_var(const char *s, int flg_export)
1723 struct variables *cur;
1727 /* Assume when we enter this function that we are already in
1728 * NAME=VALUE format. So the first order of business is to
1729 * split 's' on the '=' into 'name' and 'value' */
1730 value = strchr(name, '=');
1731 if (value==0 && ++value==0) {
1737 for(cur = top_vars; cur; cur = cur->next) {
1738 if(strcmp(cur->name, name)==0)
1743 if(strcmp(cur->value, value)==0) {
1744 if(flg_export>0 && cur->flg_export==0)
1745 cur->flg_export=flg_export;
1749 if(cur->flg_read_only) {
1750 error_msg("%s: readonly variable", name);
1753 if(flg_export>0 || cur->flg_export>1)
1757 cur->value = strdup(value);
1761 cur = malloc(sizeof(struct variables));
1765 cur->name = strdup(name);
1766 if(cur->name == 0) {
1770 struct variables *bottom = top_vars;
1771 cur->value = strdup(value);
1773 cur->flg_export = flg_export;
1774 cur->flg_read_only = 0;
1775 while(bottom->next) bottom=bottom->next;
1781 if(result==0 && cur->flg_export==1) {
1783 result = putenv(name);
1786 if(result>0) /* equivalent to previous set */
1792 static void unset_local_var(const char *name)
1794 struct variables *cur;
1797 for (cur = top_vars; cur; cur=cur->next) {
1798 if(strcmp(cur->name, name)==0)
1802 struct variables *next = top_vars;
1803 if(cur->flg_read_only) {
1804 error_msg("%s: readonly variable", name);
1808 unsetenv(cur->name);
1811 while (next->next != cur)
1813 next->next = cur->next;
1820 static int is_assignment(const char *s)
1822 if (s==NULL || !isalpha(*s)) return 0;
1824 while(isalnum(*s) || *s=='_') ++s;
1828 /* the src parameter allows us to peek forward to a possible &n syntax
1829 * for file descriptor duplication, e.g., "2>&1".
1830 * Return code is 0 normally, 1 if a syntax error is detected in src.
1831 * Resource errors (in xmalloc) cause the process to exit */
1832 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1833 struct in_str *input)
1835 struct child_prog *child=ctx->child;
1836 struct redir_struct *redir = child->redirects;
1837 struct redir_struct *last_redir=NULL;
1839 /* Create a new redir_struct and drop it onto the end of the linked list */
1844 redir = xmalloc(sizeof(struct redir_struct));
1846 redir->word.gl_pathv=NULL;
1848 last_redir->next=redir;
1850 child->redirects=redir;
1854 redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1856 debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1858 /* Check for a '2>&1' type redirect */
1859 redir->dup = redirect_dup_num(input);
1860 if (redir->dup == -2) return 1; /* syntax error */
1861 if (redir->dup != -1) {
1862 /* Erik had a check here that the file descriptor in question
1863 * is legit; I postpone that to "run time"
1864 * A "-" representation of "close me" shows up as a -3 here */
1865 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1867 /* We do _not_ try to open the file that src points to,
1868 * since we need to return and let src be expanded first.
1869 * Set ctx->pending_redirect, so we know what to do at the
1870 * end of the next parsed word.
1872 ctx->pending_redirect = redir;
1877 struct pipe *new_pipe(void) {
1879 pi = xmalloc(sizeof(struct pipe));
1883 pi->followup = 0; /* invalid */
1887 static void initialize_context(struct p_context *ctx)
1890 ctx->pending_redirect=NULL;
1892 ctx->list_head=new_pipe();
1893 ctx->pipe=ctx->list_head;
1896 done_command(ctx); /* creates the memory for working child */
1899 /* normal return is 0
1900 * if a reserved word is found, and processed, return 1
1901 * should handle if, then, elif, else, fi, for, while, until, do, done.
1902 * case, function, and select are obnoxious, save those for later.
1904 int reserved_word(o_string *dest, struct p_context *ctx)
1906 struct reserved_combo {
1911 /* Mostly a list of accepted follow-up reserved words.
1912 * FLAG_END means we are done with the sequence, and are ready
1913 * to turn the compound list into a command.
1914 * FLAG_START means the word must start a new compound list.
1916 static struct reserved_combo reserved_list[] = {
1917 { "if", RES_IF, FLAG_THEN | FLAG_START },
1918 { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
1919 { "elif", RES_ELIF, FLAG_THEN },
1920 { "else", RES_ELSE, FLAG_FI },
1921 { "fi", RES_FI, FLAG_END },
1922 { "for", RES_FOR, FLAG_DO | FLAG_START },
1923 { "while", RES_WHILE, FLAG_DO | FLAG_START },
1924 { "until", RES_UNTIL, FLAG_DO | FLAG_START },
1925 { "do", RES_DO, FLAG_DONE },
1926 { "done", RES_DONE, FLAG_END }
1928 struct reserved_combo *r;
1929 for (r=reserved_list;
1930 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
1931 r<reserved_list+NRES; r++) {
1932 if (strcmp(dest->data, r->literal) == 0) {
1933 debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
1934 if (r->flag & FLAG_START) {
1935 struct p_context *new = xmalloc(sizeof(struct p_context));
1936 debug_printf("push stack\n");
1937 *new = *ctx; /* physical copy */
1938 initialize_context(ctx);
1940 } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
1947 ctx->old_flag = r->flag;
1948 if (ctx->old_flag & FLAG_END) {
1949 struct p_context *old;
1950 debug_printf("pop stack\n");
1952 old->child->group = ctx->list_head;
1953 old->child->subshell = 0;
1954 *ctx = *old; /* physical copy */
1964 /* normal return is 0.
1965 * Syntax or xglob errors return 1. */
1966 static int done_word(o_string *dest, struct p_context *ctx)
1968 struct child_prog *child=ctx->child;
1969 glob_t *glob_target;
1972 debug_printf("done_word: %s %p\n", dest->data, child);
1973 if (dest->length == 0 && !dest->nonnull) {
1974 debug_printf(" true null, ignored\n");
1977 if (ctx->pending_redirect) {
1978 glob_target = &ctx->pending_redirect->word;
1982 return 1; /* syntax error, groups and arglists don't mix */
1985 debug_printf("checking %s for reserved-ness\n",dest->data);
1986 if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
1988 glob_target = &child->glob_result;
1989 if (child->argv) flags |= GLOB_APPEND;
1991 gr = xglob(dest, flags, glob_target);
1992 if (gr != 0) return 1;
1995 if (ctx->pending_redirect) {
1996 ctx->pending_redirect=NULL;
1997 if (glob_target->gl_pathc != 1) {
1998 error_msg("ambiguous redirect");
2002 child->argv = glob_target->gl_pathv;
2007 /* The only possible error here is out of memory, in which case
2009 static int done_command(struct p_context *ctx)
2011 /* The child is really already in the pipe structure, so
2012 * advance the pipe counter and make a new, null child.
2013 * Only real trickiness here is that the uncommitted
2014 * child structure, to which ctx->child points, is not
2015 * counted in pi->num_progs. */
2016 struct pipe *pi=ctx->pipe;
2017 struct child_prog *prog=ctx->child;
2019 if (prog && prog->group == NULL
2020 && prog->argv == NULL
2021 && prog->redirects == NULL) {
2022 debug_printf("done_command: skipping null command\n");
2026 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
2028 debug_printf("done_command: initializing\n");
2030 pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2032 prog = pi->progs + pi->num_progs;
2033 prog->redirects = NULL;
2035 prog->is_stopped = 0;
2037 prog->glob_result.gl_pathv = NULL;
2041 /* but ctx->pipe and ctx->list_head remain unchanged */
2045 static int done_pipe(struct p_context *ctx, pipe_style type)
2048 done_command(ctx); /* implicit closure of previous command */
2049 debug_printf("done_pipe, type %d\n", type);
2050 ctx->pipe->followup = type;
2051 ctx->pipe->r_mode = ctx->w;
2053 ctx->pipe->next = new_p;
2056 done_command(ctx); /* set up new pipe to accept commands */
2060 /* peek ahead in the in_str to find out if we have a "&n" construct,
2061 * as in "2>&1", that represents duplicating a file descriptor.
2062 * returns either -2 (syntax error), -1 (no &), or the number found.
2064 static int redirect_dup_num(struct in_str *input)
2068 if (ch != '&') return -1;
2070 b_getch(input); /* get the & */
2074 return -3; /* "-" represents "close me" */
2076 while (isdigit(ch)) {
2084 error_msg("ambiguous redirect");
2088 /* If a redirect is immediately preceded by a number, that number is
2089 * supposed to tell which file descriptor to redirect. This routine
2090 * looks for such preceding numbers. In an ideal world this routine
2091 * needs to handle all the following classes of redirects...
2092 * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
2093 * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
2094 * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
2095 * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
2096 * A -1 output from this program means no valid number was found, so the
2097 * caller should use the appropriate default for this redirection.
2099 static int redirect_opt_num(o_string *o)
2103 if (o->length==0) return -1;
2104 for(num=0; num<o->length; num++) {
2105 if (!isdigit(*(o->data+num))) {
2109 /* reuse num (and save an int) */
2115 FILE *generate_stream_from_list(struct pipe *head)
2119 int pid, channel[2];
2120 if (pipe(channel)<0) perror_msg_and_die("pipe");
2123 perror_msg_and_die("fork");
2124 } else if (pid==0) {
2126 if (channel[1] != 1) {
2131 #define SURROGATE "surrogate response"
2132 write(1,SURROGATE,sizeof(SURROGATE));
2133 _exit(run_list(head));
2135 _exit(run_list_real(head)); /* leaks memory */
2138 debug_printf("forked child %d\n",pid);
2140 pf = fdopen(channel[0],"r");
2141 debug_printf("pipe on FILE *%p\n",pf);
2143 free_pipe_list(head,0);
2144 pf=popen("echo surrogate response","r");
2145 debug_printf("started fake pipe on FILE *%p\n",pf);
2150 /* this version hacked for testing purposes */
2151 /* return code is exit status of the process that is run. */
2152 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2155 o_string result=NULL_O_STRING;
2156 struct p_context inner;
2158 struct in_str pipe_str;
2159 initialize_context(&inner);
2161 /* recursion to generate command */
2162 retcode = parse_stream(&result, &inner, input, subst_end);
2163 if (retcode != 0) return retcode; /* syntax error or EOF */
2164 done_word(&result, &inner);
2165 done_pipe(&inner, PIPE_SEQ);
2168 p=generate_stream_from_list(inner.list_head);
2169 if (p==NULL) return 1;
2170 mark_open(fileno(p));
2171 setup_file_in_str(&pipe_str, p);
2173 /* now send results of command back into original context */
2174 retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2175 /* XXX In case of a syntax error, should we try to kill the child?
2176 * That would be tough to do right, so just read until EOF. */
2178 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2181 debug_printf("done reading from pipe, pclose()ing\n");
2182 /* This is the step that wait()s for the child. Should be pretty
2183 * safe, since we just read an EOF from its stdout. We could try
2184 * to better, by using wait(), and keeping track of background jobs
2185 * at the same time. That would be a lot of work, and contrary
2186 * to the KISS philosophy of this program. */
2187 mark_closed(fileno(p));
2189 free_pipe_list(inner.list_head,0);
2190 debug_printf("pclosed, retcode=%d\n",retcode);
2191 /* XXX this process fails to trim a single trailing newline */
2195 static int parse_group(o_string *dest, struct p_context *ctx,
2196 struct in_str *input, int ch)
2199 struct p_context sub;
2200 struct child_prog *child = ctx->child;
2203 return 1; /* syntax error, groups and arglists don't mix */
2205 initialize_context(&sub);
2207 case '(': endch=')'; child->subshell=1; break;
2208 case '{': endch='}'; break;
2209 default: syntax(); /* really logic error */
2211 rcode=parse_stream(dest,&sub,input,endch);
2212 done_word(dest,&sub); /* finish off the final word in the subcontext */
2213 done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
2214 child->group = sub.list_head;
2216 /* child remains "open", available for possible redirects */
2219 /* basically useful version until someone wants to get fancier,
2220 * see the bash man page under "Parameter Expansion" */
2221 static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src)
2225 p = getenv(src->data);
2227 p = get_local_var(src->data);
2229 if (p) parse_string(dest, ctx, p); /* recursion */
2233 /* return code: 0 for OK, 1 for syntax error */
2234 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2237 o_string alt=NULL_O_STRING;
2239 int ch = input->peek(input); /* first character after the $ */
2240 debug_printf("handle_dollar: ch=%c\n",ch);
2242 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2246 lookup_param(dest, ctx, &alt);
2247 } else if (isdigit(ch)) {
2248 i = ch-'0'; /* XXX is $0 special? */
2249 if (i<global_argc) {
2250 parse_string(dest, ctx, global_argv[i]); /* recursion */
2253 } else switch (ch) {
2255 b_adduint(dest,getpid());
2259 if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2263 b_adduint(dest,last_return_code);
2267 b_adduint(dest,global_argc ? global_argc-1 : 0);
2272 /* XXX maybe someone will try to escape the '}' */
2273 while(ch=b_getch(input),ch!=EOF && ch!='}') {
2280 lookup_param(dest, ctx, &alt);
2284 process_command_subs(dest, ctx, input, ')');
2288 for (i=1; i<global_argc; i++) {
2289 parse_string(dest, ctx, global_argv[i]);
2290 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2296 /* still unhandled, but should be eventually */
2297 error_msg("unhandled syntax: $%c",ch);
2301 b_addqchr(dest,'$',dest->quote);
2303 /* Eat the character if the flag was set. If the compiler
2304 * is smart enough, we could substitute "b_getch(input);"
2305 * for all the "advance = 1;" above, and also end up with
2306 * a nice size-optimized program. Hah! That'll be the day.
2308 if (advance) b_getch(input);
2312 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2315 setup_string_in_str(&foo, src);
2316 return parse_stream(dest, ctx, &foo, '\0');
2319 /* return code is 0 for normal exit, 1 for syntax error */
2320 int parse_stream(o_string *dest, struct p_context *ctx,
2321 struct in_str *input, int end_trigger)
2325 redir_type redir_style;
2328 /* Only double-quote state is handled in the state variable dest->quote.
2329 * A single-quote triggers a bypass of the main loop until its mate is
2330 * found. When recursing, quote state is passed in via dest->quote. */
2332 debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2333 while ((ch=b_getch(input))!=EOF) {
2335 next = (ch == '\n') ? 0 : b_peek(input);
2336 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2337 ch,ch,m,dest->quote);
2338 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2339 b_addqchr(dest, ch, dest->quote);
2341 if (m==2) { /* unquoted IFS */
2342 done_word(dest, ctx);
2343 /* If we aren't performing a substitution, treat a newline as a
2344 * command separator. */
2345 if (end_trigger != '\0' && ch=='\n')
2346 done_pipe(ctx,PIPE_SEQ);
2348 if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2349 debug_printf("leaving parse_stream (triggered)\n");
2354 /* Yahoo! Time to run with it! */
2355 done_pipe(ctx,PIPE_SEQ);
2356 run_list(ctx->list_head);
2357 initialize_context(ctx);
2360 if (m!=2) switch (ch) {
2362 if (dest->length == 0 && !dest->quote) {
2363 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2365 b_addqchr(dest, ch, dest->quote);
2373 b_addqchr(dest, '\\', dest->quote);
2374 b_addqchr(dest, b_getch(input), dest->quote);
2377 if (handle_dollar(dest, ctx, input)!=0) return 1;
2381 while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2391 dest->quote = !dest->quote;
2394 process_command_subs(dest, ctx, input, '`');
2397 redir_fd = redirect_opt_num(dest);
2398 done_word(dest, ctx);
2399 redir_style=REDIRECT_OVERWRITE;
2401 redir_style=REDIRECT_APPEND;
2403 } else if (next == '(') {
2404 syntax(); /* until we support >(list) Process Substitution */
2407 setup_redirect(ctx, redir_fd, redir_style, input);
2410 redir_fd = redirect_opt_num(dest);
2411 done_word(dest, ctx);
2412 redir_style=REDIRECT_INPUT;
2414 redir_style=REDIRECT_HEREIS;
2416 } else if (next == '>') {
2417 redir_style=REDIRECT_IO;
2419 } else if (next == '(') {
2420 syntax(); /* until we support <(list) Process Substitution */
2423 setup_redirect(ctx, redir_fd, redir_style, input);
2426 done_word(dest, ctx);
2427 done_pipe(ctx,PIPE_SEQ);
2430 done_word(dest, ctx);
2433 done_pipe(ctx,PIPE_AND);
2435 done_pipe(ctx,PIPE_BG);
2439 done_word(dest, ctx);
2442 done_pipe(ctx,PIPE_OR);
2444 /* we could pick up a file descriptor choice here
2445 * with redirect_opt_num(), but bash doesn't do it.
2446 * "echo foo 2| cat" yields "foo 2". */
2452 if (parse_group(dest, ctx, input, ch)!=0) return 1;
2456 syntax(); /* Proper use of this character caught by end_trigger */
2460 syntax(); /* this is really an internal logic error */
2465 /* complain if quote? No, maybe we just finished a command substitution
2466 * that was quoted. Example:
2467 * $ echo "`cat foo` plus more"
2468 * and we just got the EOF generated by the subshell that ran "cat foo"
2469 * The only real complaint is if we got an EOF when end_trigger != '\0',
2470 * that is, we were really supposed to get end_trigger, and never got
2471 * one before the EOF. Can't use the standard "syntax error" return code,
2472 * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2473 debug_printf("leaving parse_stream (EOF)\n");
2474 if (end_trigger != '\0') return -1;
2478 void mapset(const unsigned char *set, int code)
2480 const unsigned char *s;
2481 for (s=set; *s; s++) map[*s] = code;
2484 void update_ifs_map(void)
2486 /* char *ifs and char map[256] are both globals. */
2487 ifs = getenv("IFS");
2488 if (ifs == NULL) ifs=" \t\n";
2489 /* Precompute a list of 'flow through' behavior so it can be treated
2490 * quickly up front. Computation is necessary because of IFS.
2491 * Special case handling of IFS == " \t\n" is not implemented.
2492 * The map[] array only really needs two bits each, and on most machines
2493 * that would be faster because of the reduced L1 cache footprint.
2495 memset(map,0,sizeof(map)); /* most characters flow through always */
2496 mapset("\\$'\"`", 3); /* never flow through */
2497 mapset("<>;&|(){}#", 1); /* flow through if quoted */
2498 mapset(ifs, 2); /* also flow through if quoted */
2501 /* most recursion does not come through here, the exeception is
2502 * from builtin_source() */
2503 int parse_stream_outer(struct in_str *inp)
2506 struct p_context ctx;
2507 o_string temp=NULL_O_STRING;
2510 initialize_context(&ctx);
2513 rcode = parse_stream(&temp, &ctx, inp, '\n');
2514 done_word(&temp, &ctx);
2515 done_pipe(&ctx,PIPE_SEQ);
2516 run_list(ctx.list_head);
2518 } while (rcode != -1); /* loop on syntax errors, return on EOF */
2522 static int parse_string_outer(const char *s)
2524 struct in_str input;
2525 setup_string_in_str(&input, s);
2526 return parse_stream_outer(&input);
2529 static int parse_file_outer(FILE *f)
2532 struct in_str input;
2533 setup_file_in_str(&input, f);
2534 rcode = parse_stream_outer(&input);
2538 /* Make sure we have a controlling tty. If we get started under a job
2539 * aware app (like bash for example), make sure we are now in charge so
2540 * we don't fight over who gets the foreground */
2541 static void setup_job_control()
2543 static pid_t shell_pgrp;
2544 /* Loop until we are in the foreground. */
2545 while (tcgetpgrp (shell_terminal) != (shell_pgrp = getpgrp ()))
2546 kill (- shell_pgrp, SIGTTIN);
2548 /* Ignore interactive and job-control signals. */
2549 signal(SIGINT, SIG_IGN);
2550 signal(SIGQUIT, SIG_IGN);
2551 signal(SIGTERM, SIG_IGN);
2552 signal(SIGTSTP, SIG_IGN);
2553 signal(SIGTTIN, SIG_IGN);
2554 signal(SIGTTOU, SIG_IGN);
2555 signal(SIGCHLD, SIG_IGN);
2557 /* Put ourselves in our own process group. */
2559 shell_pgrp = getpid ();
2560 setpgid (shell_pgrp, shell_pgrp);
2562 /* Grab control of the terminal. */
2563 tcsetpgrp(shell_terminal, shell_pgrp);
2566 int hush_main(int argc, char **argv)
2572 /* XXX what should these be while sourcing /etc/profile? */
2576 /* (re?) initialize globals. Sometimes hush_main() ends up calling
2577 * hush_main(), therefore we cannot rely on the BSS to zero out this
2578 * stuff. Reset these to 0 every time. */
2580 /* map[] is taken care of with call to update_ifs_map() */
2583 close_me_head = NULL;
2588 /* Initialize some more globals to non-zero values */
2590 #ifdef CONFIG_FEATURE_COMMAND_EDITING
2591 cmdedit_set_initial_prompt();
2597 /* initialize our shell local variables with the values
2598 * currently living in the environment */
2601 set_local_var(*e, 2); /* without call putenv() */
2604 last_return_code=EXIT_SUCCESS;
2607 if (argv[0] && argv[0][0] == '-') {
2608 debug_printf("\nsourcing /etc/profile\n");
2609 if ((input = fopen("/etc/profile", "r")) != NULL) {
2610 mark_open(fileno(input));
2611 parse_file_outer(input);
2612 mark_closed(fileno(input));
2618 while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2622 global_argv = argv+optind;
2623 global_argc = argc-optind;
2624 opt = parse_string_outer(optarg);
2636 fprintf(stderr, "Usage: sh [FILE]...\n"
2637 " or: sh -c command [args]...\n\n");
2644 /* A shell is interactive if the `-i' flag was given, or if all of
2645 * the following conditions are met:
2647 * no arguments remaining or the -s flag given
2648 * standard input is a terminal
2649 * standard output is a terminal
2650 * Refer to Posix.2, the description of the `sh' utility. */
2651 if (argv[optind]==NULL && input==stdin &&
2652 isatty(fileno(stdin)) && isatty(fileno(stdout))) {
2656 debug_printf("\ninteractive=%d\n", interactive);
2658 /* Looks like they want an interactive shell */
2659 #ifndef CONFIG_FEATURE_SH_EXTRA_QUIET
2660 printf( "\n\n" BB_BANNER " hush - the humble shell v0.01 (testing)\n");
2661 printf( "Enter 'help' for a list of built-in commands.\n\n");
2663 setup_job_control();
2666 if (argv[optind]==NULL) {
2667 opt=parse_file_outer(stdin);
2671 debug_printf("\nrunning script '%s'\n", argv[optind]);
2672 global_argv = argv+optind;
2673 global_argc = argc-optind;
2674 input = xfopen(argv[optind], "r");
2675 opt = parse_file_outer(input);
2677 #ifdef CONFIG_FEATURE_CLEAN_UP
2679 if (cwd && cwd != unknown)
2682 struct variables *cur, *tmp;
2683 for(cur = top_vars; cur; cur = tmp) {
2685 if (!cur->flg_read_only) {
2695 return(opt?opt:last_return_code);