1 /* vi: set sw=4 ts=4: */
3 * lash -- the BusyBox Lame-Ass SHell
5 * Copyright (C) 1999,2000,2001 by Lineo, inc.
6 * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
8 * Based in part on ladsh.c by Michael K. Johnson and Erik W. Troan, which is
9 * under the following liberal license: "We have placed this source code in the
10 * public domain. Use it in any project, free or commercial."
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 /* The parsing engine of this program is officially at a dead-end.
29 * Future work in that direction should move to the work posted
30 * at http://doolittle.faludi.com/~larry/parser.html .
31 * A start on the integration of that work with the rest of sh.c
32 * is at http://codepoet.org/sh.c .
35 //This works pretty well now, and is now on by default.
36 #define BB_FEATURE_SH_ENVIRONMENT
38 //Backtick support has some problems, use at your own risk!
39 //#define BB_FEATURE_SH_BACKTICKS
41 //If, then, else, etc. support.. This should now behave basically
42 //like any other Bourne shell...
43 #define BB_FEATURE_SH_IF_EXPRESSIONS
45 /* This is currently a little broken... */
46 //#define HANDLE_CONTINUATION_CHARS
48 //For debugging/development on the shell only...
59 #include <sys/ioctl.h>
67 #if ( (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) ) || defined (__UCLIBC__)
69 #define expand_t wordexp_t
70 #undef BB_FEATURE_SH_BACKTICKS
73 #define expand_t glob_t
79 static const int MAX_LINE = 256; /* size of input buffer for cwd data */
80 static const int MAX_READ = 128; /* size of input buffer for `read' builtin */
81 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
84 enum redir_type { REDIRECT_INPUT, REDIRECT_OVERWRITE,
88 static const unsigned int DEFAULT_CONTEXT=0x1;
89 static const unsigned int IF_TRUE_CONTEXT=0x2;
90 static const unsigned int IF_FALSE_CONTEXT=0x4;
91 static const unsigned int THEN_EXP_CONTEXT=0x8;
92 static const unsigned int ELSE_EXP_CONTEXT=0x10;
96 struct job *head; /* head of list of running jobs */
97 struct job *fg; /* current foreground job */
100 struct redir_struct {
101 enum redir_type type; /* type of redirection */
102 int fd; /* file descriptor being redirected */
103 char *filename; /* file to redirect fd to */
107 pid_t pid; /* 0 if exited */
108 char **argv; /* program name and arguments */
109 int num_redirects; /* elements in redirection array */
110 struct redir_struct *redirects; /* I/O redirects */
111 int is_stopped; /* is the program currently running? */
112 struct job *family; /* pointer back to the child's parent job */
116 int jobid; /* job number */
117 int num_progs; /* total number of programs in job */
118 int running_progs; /* number of programs running */
119 char *text; /* name of job */
120 char *cmdbuf; /* buffer various argv's point into */
121 pid_t pgrp; /* process group ID for the job */
122 struct child_prog *progs; /* array of programs in job */
123 struct job *next; /* to track background commands */
124 int stopped_progs; /* number of programs alive, but stopped */
125 unsigned int job_context; /* bitmask defining current context */
126 struct jobset *job_list;
129 struct built_in_command {
130 char *cmd; /* name */
131 char *descr; /* description */
132 int (*function) (struct child_prog *); /* function ptr */
137 struct close_me *next;
140 /* function prototypes for builtins */
141 static int builtin_cd(struct child_prog *cmd);
142 static int builtin_env(struct child_prog *dummy);
143 static int builtin_exec(struct child_prog *cmd);
144 static int builtin_exit(struct child_prog *cmd);
145 static int builtin_fg_bg(struct child_prog *cmd);
146 static int builtin_help(struct child_prog *cmd);
147 static int builtin_jobs(struct child_prog *dummy);
148 static int builtin_pwd(struct child_prog *dummy);
149 static int builtin_export(struct child_prog *cmd);
150 static int builtin_source(struct child_prog *cmd);
151 static int builtin_unset(struct child_prog *cmd);
152 static int builtin_read(struct child_prog *cmd);
153 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
154 static int builtin_if(struct child_prog *cmd);
155 static int builtin_then(struct child_prog *cmd);
156 static int builtin_else(struct child_prog *cmd);
157 static int builtin_fi(struct child_prog *cmd);
158 /* function prototypes for shell stuff */
159 static int run_command_predicate(char *cmd);
163 /* function prototypes for shell stuff */
164 static void mark_open(int fd);
165 static void mark_closed(int fd);
166 static void close_all(void);
167 static void checkjobs(struct jobset *job_list);
168 static int get_command(FILE * source, char *command);
169 static int parse_command(char **command_ptr, struct job *job, int *inbg);
170 static int run_command(struct job *newjob, int inbg, int outpipe[2]);
171 static int pseudo_exec(struct child_prog *cmd) __attribute__ ((noreturn));
172 static int busy_loop(FILE * input);
175 /* Table of built-in functions (these are non-forking builtins, meaning they
176 * can change global variables in the parent shell process but they will not
177 * work with pipes and redirects; 'unset foo | whatever' will not work) */
178 static struct built_in_command bltins[] = {
179 {"bg", "Resume a job in the background", builtin_fg_bg},
180 {"cd", "Change working directory", builtin_cd},
181 {"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
182 {"exit", "Exit from shell()", builtin_exit},
183 {"fg", "Bring job into the foreground", builtin_fg_bg},
184 {"jobs", "Lists the active jobs", builtin_jobs},
185 {"export", "Set environment variable", builtin_export},
186 {"unset", "Unset environment variable", builtin_unset},
187 {"read", "Input environment variable", builtin_read},
188 {".", "Source-in and run commands in a file", builtin_source},
189 /* to do: add ulimit */
190 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
191 {"if", NULL, builtin_if},
192 {"then", NULL, builtin_then},
193 {"else", NULL, builtin_else},
194 {"fi", NULL, builtin_fi},
199 /* Table of forking built-in functions (things that fork cannot change global
200 * variables in the parent process, such as the current working directory) */
201 static struct built_in_command bltins_forking[] = {
202 {"env", "Print all environment variables", builtin_env},
203 {"pwd", "Print current directory", builtin_pwd},
204 {"help", "List shell built-in commands", builtin_help},
209 /* Variables we export */
210 unsigned int shell_context; /* Used in cmdedit.c to reset the
211 context when someone hits ^C */
214 /* Globals that are static to this file */
216 static char *local_pending_command = NULL;
217 static struct jobset job_list = { NULL, NULL };
220 static struct close_me *close_me_head;
221 #ifdef BB_FEATURE_SH_ENVIRONMENT
222 static int last_bg_pid;
223 static int last_return_code;
224 static int show_x_trace;
226 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
227 static char syntax_err[]="syntax error near unexpected token";
231 static inline void debug_printf(const char *format, ...)
234 va_start(args, format);
235 vfprintf(stderr, format, args);
239 static inline void debug_printf(const char *format, ...) { }
243 Most builtins need access to the struct child_prog that has
244 their arguments, previously coded as cmd->progs[0]. That coding
245 can exhibit a bug, if the builtin is not the first command in
246 a pipeline: "echo foo | exec sort" will attempt to exec foo.
248 builtin previous use notes
249 ------ ----------------- ---------
252 exec cmd->progs[0] squashed bug: didn't look for applets or forking builtins
254 fg_bg cmd->progs[0], job_list->head, job_list->fg
258 export cmd->progs[0] passes cmd, job_list to builtin_env(), which ignores them
262 if cmd->job_context, cmd->text
263 then cmd->job_context, cmd->text
264 else cmd->job_context, cmd->text
267 The use of cmd->text by if/then/else/fi is hopelessly hacky.
268 Would it work to increment cmd->progs[0]->argv and recurse,
269 somewhat like builtin_exec does?
271 I added "struct job *family;" to struct child_prog,
272 and switched API to builtin_foo(struct child_prog *child);
273 So cmd->text becomes child->family->text
274 cmd->job_context becomes child->family->job_context
275 cmd->progs[0] becomes *child
276 job_list becomes child->family->job_list
279 /* built-in 'cd <path>' handler */
280 static int builtin_cd(struct child_prog *child)
284 if (child->argv[1] == NULL)
285 newdir = getenv("HOME");
287 newdir = child->argv[1];
289 printf("cd: %s: %s\n", newdir, strerror(errno));
292 getcwd(cwd, sizeof(char)*MAX_LINE);
297 /* built-in 'env' handler */
298 static int builtin_env(struct child_prog *dummy)
302 for (e = environ; *e; e++) {
308 /* built-in 'exec' handler */
309 static int builtin_exec(struct child_prog *child)
311 if (child->argv[1] == NULL)
312 return EXIT_SUCCESS; /* Really? */
319 /* built-in 'exit' handler */
320 static int builtin_exit(struct child_prog *child)
322 if (child->argv[1] == NULL)
325 exit (atoi(child->argv[1]));
328 /* built-in 'fg' and 'bg' handler */
329 static int builtin_fg_bg(struct child_prog *child)
332 struct job *job=NULL;
334 if (!child->argv[1] || child->argv[2]) {
335 error_msg("%s: exactly one argument is expected",
340 if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) {
341 error_msg("%s: bad argument '%s'",
342 child->argv[0], child->argv[1]);
346 for (job = child->family->job_list->head; job; job = job->next) {
347 if (job->jobid == jobNum) {
353 error_msg("%s: unknown job %d",
354 child->argv[0], jobNum);
358 if (*child->argv[0] == 'f') {
359 /* Make this job the foreground job */
360 /* suppress messages when run from /linuxrc mag@sysgo.de */
361 if (tcsetpgrp(0, job->pgrp) && errno != ENOTTY)
362 perror_msg("tcsetpgrp");
363 child->family->job_list->fg = job;
366 /* Restart the processes in the job */
367 for (i = 0; i < job->num_progs; i++)
368 job->progs[i].is_stopped = 0;
370 kill(-job->pgrp, SIGCONT);
372 job->stopped_progs = 0;
377 /* built-in 'help' handler */
378 static int builtin_help(struct child_prog *dummy)
380 struct built_in_command *x;
382 printf("\nBuilt-in commands:\n");
383 printf("-------------------\n");
384 for (x = bltins; x->cmd; x++) {
387 printf("%s\t%s\n", x->cmd, x->descr);
389 for (x = bltins_forking; x->cmd; x++) {
392 printf("%s\t%s\n", x->cmd, x->descr);
398 /* built-in 'jobs' handler */
399 static int builtin_jobs(struct child_prog *child)
404 for (job = child->family->job_list->head; job; job = job->next) {
405 if (job->running_progs == job->stopped_progs)
406 status_string = "Stopped";
408 status_string = "Running";
410 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
416 /* built-in 'pwd' handler */
417 static int builtin_pwd(struct child_prog *dummy)
419 getcwd(cwd, MAX_LINE);
420 printf( "%s\n", cwd);
424 /* built-in 'export VAR=value' handler */
425 static int builtin_export(struct child_prog *child)
429 if (child->argv[1] == NULL) {
430 return (builtin_env(child));
432 res = putenv(child->argv[1]);
434 fprintf(stderr, "export: %s\n", strerror(errno));
438 /* built-in 'read VAR' handler */
439 static int builtin_read(struct child_prog *child)
441 int res = 0, len, newlen;
443 char string[MAX_READ];
445 if (child->argv[1]) {
446 /* argument (VAR) given: put "VAR=" into buffer */
447 strcpy(string, child->argv[1]);
448 len = strlen(string);
451 fgets(&string[len], sizeof(string) - len, stdin); /* read string */
452 newlen = strlen(string);
454 string[--newlen] = '\0'; /* chomp trailing newline */
456 ** string should now contain "VAR=<value>"
457 ** copy it (putenv() won't do that, so we must make sure
458 ** the string resides in a static buffer!)
461 if((s = strdup(string)))
464 fprintf(stderr, "read: %s\n", strerror(errno));
467 fgets(string, sizeof(string), stdin);
472 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
473 /* Built-in handler for 'if' commands */
474 static int builtin_if(struct child_prog *child)
476 struct job *cmd = child->family;
478 char* charptr1=cmd->text+3; /* skip over the leading 'if ' */
480 /* Now run the 'if' command */
481 debug_printf( "job=%p entering builtin_if ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
482 status = run_command_predicate(charptr1);
483 debug_printf( "if test returned ");
485 debug_printf( "TRUE\n");
486 cmd->job_context |= IF_TRUE_CONTEXT;
488 debug_printf( "FALSE\n");
489 cmd->job_context |= IF_FALSE_CONTEXT;
491 debug_printf("job=%p builtin_if set job context to %x\n", cmd, cmd->job_context);
497 /* Built-in handler for 'then' (part of the 'if' command) */
498 static int builtin_then(struct child_prog *child)
500 struct job *cmd = child->family;
501 char* charptr1=cmd->text+5; /* skip over the leading 'then ' */
503 debug_printf( "job=%p entering builtin_then ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
504 if (! (cmd->job_context & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
505 shell_context = 0; /* Reset the shell's context on an error */
506 error_msg("%s `then'", syntax_err);
510 cmd->job_context |= THEN_EXP_CONTEXT;
511 debug_printf("job=%p builtin_then set job context to %x\n", cmd, cmd->job_context);
513 /* If the if result was FALSE, skip the 'then' stuff */
514 if (cmd->job_context & IF_FALSE_CONTEXT) {
518 /* Seems the if result was TRUE, so run the 'then' command */
519 debug_printf( "'then' now running '%s'\n", charptr1);
521 return(run_command_predicate(charptr1));
524 /* Built-in handler for 'else' (part of the 'if' command) */
525 static int builtin_else(struct child_prog *child)
527 struct job *cmd = child->family;
528 char* charptr1=cmd->text+5; /* skip over the leading 'else ' */
530 debug_printf( "job=%p entering builtin_else ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
532 if (! (cmd->job_context & THEN_EXP_CONTEXT)) {
533 shell_context = 0; /* Reset the shell's context on an error */
534 error_msg("%s `else'", syntax_err);
537 /* If the if result was TRUE, skip the 'else' stuff */
538 if (cmd->job_context & IF_TRUE_CONTEXT) {
542 cmd->job_context |= ELSE_EXP_CONTEXT;
543 debug_printf("job=%p builtin_else set job context to %x\n", cmd, cmd->job_context);
545 /* Now run the 'else' command */
546 debug_printf( "'else' now running '%s'\n", charptr1);
547 return(run_command_predicate(charptr1));
550 /* Built-in handler for 'fi' (part of the 'if' command) */
551 static int builtin_fi(struct child_prog *child)
553 struct job *cmd = child->family;
554 debug_printf( "job=%p entering builtin_fi ('%s')-- context=%d\n", cmd, "", cmd->job_context);
555 if (! (cmd->job_context & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
556 shell_context = 0; /* Reset the shell's context on an error */
557 error_msg("%s `fi'", syntax_err);
560 /* Clear out the if and then context bits */
561 cmd->job_context &= ~(IF_TRUE_CONTEXT|IF_FALSE_CONTEXT|THEN_EXP_CONTEXT|ELSE_EXP_CONTEXT);
562 debug_printf("job=%p builtin_fi set job context to %x\n", cmd, cmd->job_context);
568 /* Built-in '.' handler (read-in and execute commands from file) */
569 static int builtin_source(struct child_prog *child)
575 if (child->argv[1] == NULL)
578 input = fopen(child->argv[1], "r");
580 printf( "Couldn't open file '%s'\n", child->argv[1]);
586 /* Now run the file */
587 status = busy_loop(input);
593 /* built-in 'unset VAR' handler */
594 static int builtin_unset(struct child_prog *child)
596 if (child->argv[1] == NULL) {
597 printf( "unset: parameter required.\n");
600 unsetenv(child->argv[1]);
604 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
605 /* currently used by if/then/else.
607 * Reparsing the command line for this purpose is gross,
608 * incorrect, and fundamentally unfixable; in particular,
609 * think about what happens with command substitution.
610 * We really need to pull out the run, wait, return status
611 * functionality out of busy_loop so we can child->argv++
612 * and use that, without going back through parse_command.
614 static int run_command_predicate(char *cmd)
617 local_pending_command = xmalloc(n+1);
618 strncpy(local_pending_command, cmd, n);
619 local_pending_command[n]='\0';
620 return( busy_loop(NULL));
624 static void mark_open(int fd)
626 struct close_me *new = xmalloc(sizeof(struct close_me));
628 new->next = close_me_head;
632 static void mark_closed(int fd)
634 struct close_me *tmp;
635 if (close_me_head == NULL || close_me_head->fd != fd)
636 error_msg_and_die("corrupt close_me");
638 close_me_head = close_me_head->next;
642 static void close_all()
644 struct close_me *c, *tmp;
645 for (c=close_me_head; c; c=tmp) {
650 close_me_head = NULL;
654 /* free up all memory from a job */
655 static void free_job(struct job *cmd)
659 for (i = 0; i < cmd->num_progs; i++) {
660 free(cmd->progs[i].argv);
661 if (cmd->progs[i].redirects)
662 free(cmd->progs[i].redirects);
668 memset(cmd, 0, sizeof(struct job));
671 /* remove a job from the job_list */
672 static void remove_job(struct jobset *job_list, struct job *job)
677 if (job == job_list->head) {
678 job_list->head = job->next;
680 prevjob = job_list->head;
681 while (prevjob->next != job)
682 prevjob = prevjob->next;
683 prevjob->next = job->next;
689 /* Checks to see if any background processes have exited -- if they
690 have, figure out why and see if a job has completed */
691 static void checkjobs(struct jobset *job_list)
698 while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
699 for (job = job_list->head; job; job = job->next) {
701 while (prognum < job->num_progs &&
702 job->progs[prognum].pid != childpid) prognum++;
703 if (prognum < job->num_progs)
707 /* This happens on backticked commands */
711 if (WIFEXITED(status) || WIFSIGNALED(status)) {
713 job->running_progs--;
714 job->progs[prognum].pid = 0;
716 if (!job->running_progs) {
717 printf(JOB_STATUS_FORMAT, job->jobid, "Done", job->text);
718 remove_job(job_list, job);
722 job->stopped_progs++;
723 job->progs[prognum].is_stopped = 1;
725 if (job->stopped_progs == job->num_progs) {
726 printf(JOB_STATUS_FORMAT, job->jobid, "Stopped",
732 if (childpid == -1 && errno != ECHILD)
733 perror_msg("waitpid");
736 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
737 * and stderr if they are redirected. */
738 static int setup_redirects(struct child_prog *prog, int squirrel[])
743 struct redir_struct *redir = prog->redirects;
745 for (i = 0; i < prog->num_redirects; i++, redir++) {
746 switch (redir->type) {
750 case REDIRECT_OVERWRITE:
751 mode = O_WRONLY | O_CREAT | O_TRUNC;
753 case REDIRECT_APPEND:
754 mode = O_WRONLY | O_CREAT | O_APPEND;
758 openfd = open(redir->filename, mode, 0666);
760 /* this could get lost if stderr has been redirected, but
761 bash and ash both lose it as well (though zsh doesn't!) */
762 error_msg("error opening %s: %s", redir->filename,
767 if (openfd != redir->fd) {
768 if (squirrel && redir->fd < 3) {
769 squirrel[redir->fd] = dup(redir->fd);
771 dup2(openfd, redir->fd);
779 static void restore_redirects(int squirrel[])
782 for (i=0; i<3; i++) {
785 /* No error checking. I sure wouldn't know what
786 * to do with an error if I found one! */
793 #if defined(BB_FEATURE_SH_SIMPLE_PROMPT)
794 static char* setup_prompt_string(int state)
796 char prompt_str[BUFSIZ];
798 /* Set up the prompt */
801 sprintf(prompt_str, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# ");
803 strcpy(prompt_str,"> ");
806 return(strdup(prompt_str)); /* Must free this memory */
811 static char* setup_prompt_string(int state)
813 char user[9],buf[255],*s;
815 char prompt_str[BUFSIZ];
817 /* Set up the prompt */
819 /* get User Name and setup prompt */
820 strcpy(prompt,( geteuid() != 0 ) ? "$ ":"# ");
821 my_getpwuid(user, geteuid());
824 gethostname(buf, 255);
825 s = strchr(buf, '.');
834 snprintf(prompt_str, BUFSIZ-1, "[%s@%s %s]%s", user, buf,
835 get_last_path_component(cwd), prompt);
837 sprintf(prompt_str, "%s", prompt);
839 return(strdup(prompt_str)); /* Must free this memory */
844 static int get_command(FILE * source, char *command)
848 if (source == NULL) {
849 if (local_pending_command) {
850 /* a command specified (-c option): return it & mark it done */
851 strcpy(command, local_pending_command);
852 free(local_pending_command);
853 local_pending_command = NULL;
859 if (source == stdin) {
860 prompt_str = setup_prompt_string(shell_context);
862 #ifdef BB_FEATURE_SH_COMMAND_EDITING
864 ** enable command line editing only while a command line
865 ** is actually being read; otherwise, we'll end up bequeathing
866 ** atexit() handlers and other unwanted stuff to our
867 ** child processes (rob@sysgo.de)
869 cmdedit_read_input(prompt_str, command);
874 fputs(prompt_str, stdout);
879 if (!fgets(command, BUFSIZ - 2, source)) {
885 /* remove trailing newline */
891 #ifdef BB_FEATURE_SH_ENVIRONMENT
892 static char* itoa(register int i)
894 static char a[7]; /* Max 7 ints */
895 register char *b = a + sizeof(a) - 1;
903 *--b = '0' + (i % 10);
913 static int expand_arguments(char *command)
915 #ifdef BB_FEATURE_SH_ENVIRONMENT
916 expand_t expand_result;
917 char *src, *dst, *var;
918 int i=0, length, total_length=0, retval;
921 /* get rid of the terminating \n */
924 #ifdef BB_FEATURE_SH_ENVIRONMENT
927 #if ( (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) ) || defined (__UCLIBC__)
928 /* This first part uses wordexp() which is a wonderful C lib
929 * function which expands nearly everything. */
930 retval = wordexp (command, &expand_result, 0);
931 if (retval == WRDE_NOSPACE) {
932 /* Mem may have been allocated... */
933 wordfree (&expand_result);
934 error_msg("out of space during expansion");
938 /* Some other error. */
939 error_msg("syntax error");
943 /* Convert from char** (one word per string) to a simple char*,
944 * but don't overflow command which is BUFSIZ in length */
946 while (i < expand_result.we_wordc && total_length < BUFSIZ) {
947 length=strlen(expand_result.we_wordv[i])+1;
948 if (BUFSIZ-total_length-length <= 0) {
949 error_msg("out of space during expansion");
952 strcat(command+total_length, expand_result.we_wordv[i++]);
953 strcat(command+total_length, " ");
954 total_length+=length;
956 wordfree (&expand_result);
959 /* Ok. They don't have glibc and they don't have uClibc. Chances are
960 * about 100% they don't have wordexp(), so instead, the best we can do is
961 * use glob, which is better then nothing, but certainly not perfect */
963 /* It turns out that glob is very stupid. We have to feed it
964 * one word at a time since it can't cope with a full string.
965 * Here we convert command (char*) into cmd (char**, one word
969 int flags = GLOB_NOCHECK|GLOB_BRACE|GLOB_TILDE;
971 /* We need a clean copy, so strsep can mess up the copy while
972 * we write stuff into the original in a minute */
973 char * cmd = strdup(command);
974 for (tmpcmd = cmd; (tmpcmd = strsep(&cmd, " \t")) != NULL;) {
977 retval = glob(tmpcmd, flags, NULL, &expand_result);
978 /* We can't haveGLOB_APPEND on the first glob call,
979 * so put it there now */
980 if (! (flags & GLOB_APPEND) )
981 flags |= GLOB_APPEND;
983 if (retval == GLOB_NOSPACE) {
984 /* Mem may have been allocated... */
985 globfree (&expand_result);
986 error_msg("out of space during expansion");
989 if (retval != 0 && retval != GLOB_NOMATCH) {
990 /* Some other error. */
991 error_msg("syntax error");
995 /* Convert from char** (one word per string) to a simple char*,
996 * but don't overflow command which is BUFSIZ in length */
998 if ( expand_result.gl_pathc > 1) {
999 while (i < expand_result.gl_pathc && total_length < BUFSIZ) {
1000 length=strlen(expand_result.gl_pathv[i])+1;
1001 if (BUFSIZ-total_length-length <= 0) {
1002 error_msg("out of space during expansion");
1005 strcat(command+total_length, expand_result.gl_pathv[i++]);
1006 strcat(command+total_length, " ");
1007 total_length+=length;
1013 globfree (&expand_result);
1018 /* FIXME -- this routine (which is only used when folks
1019 * don't have a C library with wordexp) needs a bit of help
1020 * to handle things like 'echo $PATH$0' */
1022 /* Now do the shell variable substitutions which
1023 * wordexp can't do for us, namely $? and $! */
1025 while((dst = strchr(src,'$')) != NULL){
1026 /* Ok -- got a $ -- now clean up any trailing mess */
1028 if (!(var = getenv(dst + 1))) {
1031 var = itoa(last_return_code);
1034 if (last_bg_pid==-1)
1037 var = itoa(last_bg_pid);
1039 /* Everything else like $$, $#, $[0-9], etc should all be
1040 * expanded by wordexp(), so we can in theory skip that stuff
1041 * here, but just to be on the safe side (i.e. since uClibc
1042 * wordexp doesn't do this stuff yet), lets leave it in for
1045 var = itoa(getpid());
1050 case '0':case '1':case '2':case '3':case '4':
1051 case '5':case '6':case '7':case '8':case '9':
1053 int index=*(dst + 1)-48;
1054 if (index >= argc) {
1065 int subst_len = strlen(var);
1067 if ((next_dst=strpbrk(dst+1, " \t~`!$^&*()=|\\{}[];\"'<>?")) == NULL) {
1070 src = (char*)xrealloc(src, strlen(src) - strlen(next_dst)+strlen(var)+1);
1071 /* Move stuff to the end of the string to accommodate filling
1072 * the created gap with the new stuff */
1073 memmove(dst+subst_len, next_dst+1, subst_len);
1074 /* Now copy in the new stuff */
1075 strncpy(dst, var, subst_len+1);
1079 /* Seems we got an un-expandable variable. So delete it. */
1081 if ((next_dst=strpbrk(dst+1, " \t~`!$^&*()=|\\{}[];\"'<>?")) != NULL) {
1082 /* Move stuff to the end of the string to accommodate filling
1083 * the created gap with the new stuff */
1084 memmove(dst, next_dst, next_dst-dst);
1096 /* Return cmd->num_progs as 0 if no command is present (e.g. an empty
1097 line). If a valid command is found, command_ptr is set to point to
1098 the beginning of the next command (if the original command had more
1099 then one job associated with it) or NULL if no more commands are
1101 static int parse_command(char **command_ptr, struct job *job, int *inbg)
1104 char *return_command = NULL;
1105 char *src, *buf, *chptr;
1112 struct child_prog *prog;
1114 /* skip leading white space */
1115 while (**command_ptr && isspace(**command_ptr))
1118 /* this handles empty lines or leading '#' characters */
1119 if (!**command_ptr || (**command_ptr == '#')) {
1126 job->progs = xmalloc(sizeof(*job->progs));
1128 /* We set the argv elements to point inside of this string. The
1129 memory is freed by free_job(). Allocate twice the original
1130 length in case we need to quote every single character.
1132 Getting clean memory relieves us of the task of NULL
1133 terminating things and makes the rest of this look a bit
1134 cleaner (though it is, admittedly, a tad less efficient) */
1135 job->cmdbuf = command = xcalloc(2*strlen(*command_ptr) + 1, sizeof(char));
1139 prog->num_redirects = 0;
1140 prog->redirects = NULL;
1141 prog->is_stopped = 0;
1145 prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1146 prog->argv[0] = job->cmdbuf;
1150 while (*src && !done) {
1151 if (quote == *src) {
1157 error_msg("character expected after \\");
1162 /* in shell, "\'" should yield \' */
1163 if (*src != quote) {
1167 } else if (*src == '*' || *src == '?' || *src == '[' ||
1168 *src == ']') *buf++ = '\\';
1170 } else if (isspace(*src)) {
1171 if (*prog->argv[argc_l]) {
1173 /* +1 here leaves room for the NULL which ends argv */
1174 if ((argc_l + 1) == argv_alloced) {
1176 prog->argv = xrealloc(prog->argv,
1177 sizeof(*prog->argv) *
1180 prog->argv[argc_l] = buf;
1189 case '#': /* comment */
1196 case '>': /* redirects */
1198 i = prog->num_redirects++;
1199 prog->redirects = xrealloc(prog->redirects,
1200 sizeof(*prog->redirects) *
1203 prog->redirects[i].fd = -1;
1204 if (buf != prog->argv[argc_l]) {
1205 /* the stuff before this character may be the file number
1207 prog->redirects[i].fd =
1208 strtol(prog->argv[argc_l], &chptr, 10);
1210 if (*chptr && *prog->argv[argc_l]) {
1212 prog->argv[argc_l] = buf;
1216 if (prog->redirects[i].fd == -1) {
1218 prog->redirects[i].fd = 1;
1220 prog->redirects[i].fd = 0;
1223 if (*src++ == '>') {
1225 prog->redirects[i].type =
1226 REDIRECT_APPEND, src++;
1228 prog->redirects[i].type = REDIRECT_OVERWRITE;
1230 prog->redirects[i].type = REDIRECT_INPUT;
1233 /* This isn't POSIX sh compliant. Oh well. */
1235 while (isspace(*chptr))
1239 error_msg("file name expected after %c", *src);
1245 prog->redirects[i].filename = buf;
1246 while (*chptr && !isspace(*chptr))
1249 src = chptr - 1; /* we src++ later */
1250 prog->argv[argc_l] = ++buf;
1253 case '|': /* pipe */
1254 /* finish this command */
1255 if (*prog->argv[argc_l])
1258 error_msg("empty command in pipe");
1263 prog->argv[argc_l] = NULL;
1265 /* and start the next */
1267 job->progs = xrealloc(job->progs,
1268 sizeof(*job->progs) * job->num_progs);
1269 prog = job->progs + (job->num_progs - 1);
1270 prog->num_redirects = 0;
1271 prog->redirects = NULL;
1272 prog->is_stopped = 0;
1277 prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1278 prog->argv[0] = ++buf;
1281 while (*src && isspace(*src))
1285 error_msg("empty command in pipe");
1290 src--; /* we'll ++ it at the end of the loop */
1294 case '&': /* background */
1296 case ';': /* multiple commands */
1298 return_command = *command_ptr + (src - *command_ptr) + 1;
1301 #ifdef BB_FEATURE_SH_BACKTICKS
1303 /* Exec a backtick-ed command */
1304 /* Besides any previous brokenness, I have not
1305 * updated backtick handling for close_me support.
1306 * I don't know if it needs it or not. -- LRD */
1308 char* charptr1=NULL, *charptr2;
1311 struct jobset njob_list = { NULL, NULL };
1315 ptr=strchr(++src, '`');
1317 fprintf(stderr, "Unmatched '`' in command\n");
1322 /* Make some space to hold just the backticked command */
1323 charptr1 = charptr2 = xmalloc(1+ptr-src);
1324 memcpy(charptr1, src, ptr-src);
1325 charptr1[ptr-src] = '\0';
1326 newjob = xmalloc(sizeof(struct job));
1327 newjob->job_list = &njob_list;
1328 /* Now parse and run the backticked command */
1329 if (!parse_command(&charptr1, newjob, inbg)
1330 && newjob->num_progs) {
1332 run_command(newjob, 0, pipefd);
1334 checkjobs(job->job_list);
1335 free_job(newjob); /* doesn't actually free newjob,
1336 looks like a memory leak */
1339 /* Make a copy of any stuff left over in the command
1340 * line after the second backtick */
1341 charptr2 = xmalloc(strlen(ptr)+1);
1342 memcpy(charptr2, ptr+1, strlen(ptr));
1345 /* Copy the output from the backtick-ed command into the
1346 * command line, making extra room as needed */
1348 charptr1 = xmalloc(BUFSIZ);
1349 while ( (size=full_read(pipefd[0], charptr1, BUFSIZ-1)) >0) {
1350 int newsize=src - *command_ptr + size + 1 + strlen(charptr2);
1351 if (newsize > BUFSIZ) {
1352 *command_ptr=xrealloc(*command_ptr, newsize);
1354 memcpy(src, charptr1, size);
1362 /* Now paste into the *command_ptr all the stuff
1363 * leftover after the second backtick */
1364 memcpy(src, charptr2, strlen(charptr2)+1);
1367 /* Now recursively call parse_command to deal with the new
1368 * and improved version of the command line with the backtick
1369 * results expanded in place... */
1371 struct jobset *jl=job->job_list;
1375 return(parse_command(command_ptr, job, inbg));
1378 #endif // BB_FEATURE_SH_BACKTICKS
1383 /* This is currently a little broken... */
1384 #ifdef HANDLE_CONTINUATION_CHARS
1385 /* They fed us a continuation char, so continue reading stuff
1386 * on the next line, then tack that onto the end of the current
1390 printf("erik: found a continue char at EOL...\n");
1391 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1392 if (get_command(input, command)) {
1393 error_msg("character expected after \\");
1398 newsize = strlen(*command_ptr) + strlen(command) + 2;
1399 if (newsize > BUFSIZ) {
1400 printf("erik: doing realloc\n");
1401 *command_ptr=xrealloc(*command_ptr, newsize);
1403 printf("erik: A: *command_ptr='%s'\n", *command_ptr);
1404 memcpy(--src, command, strlen(command));
1405 printf("erik: B: *command_ptr='%s'\n", *command_ptr);
1409 error_msg("character expected after \\");
1415 if (*src == '*' || *src == '[' || *src == ']'
1416 || *src == '?') *buf++ = '\\';
1425 if (*prog->argv[argc_l]) {
1432 prog->argv[argc_l] = NULL;
1434 if (!return_command) {
1435 job->text = xmalloc(strlen(*command_ptr) + 1);
1436 strcpy(job->text, *command_ptr);
1438 /* This leaves any trailing spaces, which is a bit sloppy */
1439 count = return_command - *command_ptr;
1440 job->text = xmalloc(count + 1);
1441 strncpy(job->text, *command_ptr, count);
1442 job->text[count] = '\0';
1445 *command_ptr = return_command;
1450 /* Run the child_prog, no matter what kind of command it uses.
1452 static int pseudo_exec(struct child_prog *child)
1454 struct built_in_command *x;
1455 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1459 /* Check if the command matches any of the non-forking builtins.
1460 * Depending on context, this might be redundant. But it's
1461 * easier to waste a few CPU cycles than it is to figure out
1462 * if this is one of those cases.
1464 for (x = bltins; x->cmd; x++) {
1465 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1466 exit(x->function(child));
1470 /* Check if the command matches any of the forking builtins. */
1471 for (x = bltins_forking; x->cmd; x++) {
1472 if (strcmp(child->argv[0], x->cmd) == 0) {
1474 exit (x->function(child));
1477 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1478 /* Check if the command matches any busybox internal
1479 * commands ("applets") here. Following discussions from
1480 * November 2000 on busybox@opensource.lineo.com, don't use
1481 * get_last_path_component(). This way explicit (with
1482 * slashes) filenames will never be interpreted as an
1483 * applet, just like with builtins. This way the user can
1484 * override an applet with an explicit filename reference.
1485 * The only downside to this change is that an explicit
1486 * /bin/foo invocation will fork and exec /bin/foo, even if
1487 * /bin/foo is a symlink to busybox.
1489 name = child->argv[0];
1491 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1492 /* If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then
1493 * if you run /bin/cat, it will use BusyBox cat even if
1494 * /bin/cat exists on the filesystem and is _not_ busybox.
1495 * Some systems want this, others do not. Choose wisely. :-)
1497 name = get_last_path_component(name);
1501 char** argv=child->argv;
1503 for(argc_l=0;*argv!=NULL; argv++, argc_l++);
1505 run_applet_by_name(name, argc_l, child->argv);
1509 execvp(child->argv[0], child->argv);
1510 perror_msg_and_die("%s", child->argv[0]);
1513 static void insert_job(struct job *newjob, int inbg)
1516 struct jobset *job_list=newjob->job_list;
1518 /* find the ID for thejob to use */
1520 for (thejob = job_list->head; thejob; thejob = thejob->next)
1521 if (thejob->jobid >= newjob->jobid)
1522 newjob->jobid = thejob->jobid + 1;
1524 /* add thejob to the list of running jobs */
1525 if (!job_list->head) {
1526 thejob = job_list->head = xmalloc(sizeof(*thejob));
1528 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1529 thejob->next = xmalloc(sizeof(*thejob));
1530 thejob = thejob->next;
1533 *thejob = *newjob; /* physically copy the struct job */
1534 thejob->next = NULL;
1535 thejob->running_progs = thejob->num_progs;
1536 thejob->stopped_progs = 0;
1539 /* we don't wait for background thejobs to return -- append it
1540 to the list of backgrounded thejobs and leave it alone */
1541 printf("[%d] %d\n", thejob->jobid,
1542 newjob->progs[newjob->num_progs - 1].pid);
1543 #ifdef BB_FEATURE_SH_ENVIRONMENT
1544 last_bg_pid=newjob->progs[newjob->num_progs - 1].pid;
1547 newjob->job_list->fg = thejob;
1549 /* move the new process group into the foreground */
1550 /* suppress messages when run from /linuxrc mag@sysgo.de */
1551 if (tcsetpgrp(0, newjob->pgrp) && errno != ENOTTY)
1552 perror_msg("tcsetpgrp");
1556 static int run_command(struct job *newjob, int inbg, int outpipe[2])
1558 /* struct job *thejob; */
1560 int nextin, nextout;
1561 int pipefds[2]; /* pipefd[0] is for reading */
1562 struct built_in_command *x;
1563 struct child_prog *child;
1565 nextin = 0, nextout = 1;
1566 for (i = 0; i < newjob->num_progs; i++) {
1567 child = & (newjob->progs[i]);
1569 if ((i + 1) < newjob->num_progs) {
1570 if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1571 nextout = pipefds[1];
1573 if (outpipe[1]!=-1) {
1574 nextout = outpipe[1];
1580 #ifdef BB_FEATURE_SH_ENVIRONMENT
1581 if (show_x_trace==TRUE) {
1584 for (j = 0; child->argv[j]; j++) {
1586 fputs(child->argv[j], stderr);
1588 fputc('\n', stderr);
1592 /* Check if the command matches any non-forking builtins,
1593 * but only if this is a simple command.
1594 * Non-forking builtins within pipes have to fork anyway,
1595 * and are handled in pseudo_exec. "echo foo | read bar"
1596 * is doomed to failure, and doesn't work on bash, either.
1598 if (newjob->num_progs == 1) {
1599 for (x = bltins; x->cmd; x++) {
1600 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1601 int squirrel[] = {-1, -1, -1};
1603 setup_redirects(child, squirrel);
1604 rcode = x->function(child);
1605 restore_redirects(squirrel);
1611 if (!(child->pid = fork())) {
1612 signal(SIGTTOU, SIG_DFL);
1616 if (outpipe[1]!=-1) {
1626 dup2(nextout, 2); /* Really? */
1631 /* explicit redirects override pipes */
1632 setup_redirects(child,NULL);
1636 if (outpipe[1]!=-1) {
1640 /* put our child in the process group whose leader is the
1641 first process in this pipe */
1642 setpgid(child->pid, newjob->progs[0].pid);
1648 /* If there isn't another process, nextin is garbage
1649 but it doesn't matter */
1650 nextin = pipefds[0];
1653 newjob->pgrp = newjob->progs[0].pid;
1655 insert_job(newjob, inbg);
1660 static int busy_loop(FILE * input)
1663 char *next_command = NULL;
1669 newjob.job_list = &job_list;
1670 newjob.job_context = DEFAULT_CONTEXT;
1672 /* save current owner of TTY so we can restore it on exit */
1673 parent_pgrp = tcgetpgrp(0);
1675 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1677 /* don't pay any attention to this signal; it just confuses
1678 things and isn't really meant for shells anyway */
1679 signal(SIGTTOU, SIG_IGN);
1683 /* no job is in the foreground */
1685 /* see if any background processes have exited */
1686 checkjobs(&job_list);
1688 if (!next_command) {
1689 if (get_command(input, command))
1691 next_command = command;
1694 if (expand_arguments(next_command) == FALSE) {
1696 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1697 next_command = NULL;
1701 if (!parse_command(&next_command, &newjob, &inbg) &&
1703 int pipefds[2] = {-1,-1};
1704 debug_printf( "job=%p being fed to run_command by busy_loop()'\n", &newjob);
1705 run_command(&newjob, inbg, pipefds);
1709 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1710 next_command = NULL;
1713 /* a job is running in the foreground; wait for it */
1715 while (!job_list.fg->progs[i].pid ||
1716 job_list.fg->progs[i].is_stopped == 1) i++;
1718 if (waitpid(job_list.fg->progs[i].pid, &status, WUNTRACED)<0)
1719 perror_msg_and_die("waitpid(%d)",job_list.fg->progs[i].pid);
1721 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1722 /* the child exited */
1723 job_list.fg->running_progs--;
1724 job_list.fg->progs[i].pid = 0;
1726 #ifdef BB_FEATURE_SH_ENVIRONMENT
1727 last_return_code=WEXITSTATUS(status);
1728 debug_printf("'%s' exited -- return code %d\n",
1729 job_list.fg->text, last_return_code);
1731 if (!job_list.fg->running_progs) {
1733 remove_job(&job_list, job_list.fg);
1737 /* the child was stopped */
1738 job_list.fg->stopped_progs++;
1739 job_list.fg->progs[i].is_stopped = 1;
1741 if (job_list.fg->stopped_progs == job_list.fg->running_progs) {
1742 printf("\n" JOB_STATUS_FORMAT, job_list.fg->jobid,
1743 "Stopped", job_list.fg->text);
1749 /* move the shell to the foreground */
1750 /* suppress messages when run from /linuxrc mag@sysgo.de */
1751 if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
1752 perror_msg("tcsetpgrp");
1758 /* return controlling TTY back to parent process group before exiting */
1759 if (tcsetpgrp(0, parent_pgrp))
1760 perror_msg("tcsetpgrp");
1762 /* return exit status if called with "-c" */
1763 if (input == NULL && WIFEXITED(status))
1764 return WEXITSTATUS(status);
1770 #ifdef BB_FEATURE_CLEAN_UP
1771 void free_memory(void)
1775 if (local_pending_command)
1776 free(local_pending_command);
1778 if (job_list.fg && !job_list.fg->running_progs) {
1779 remove_job(&job_list, job_list.fg);
1785 int shell_main(int argc_l, char **argv_l)
1787 int opt, interactive=FALSE;
1788 FILE *input = stdin;
1792 /* These variables need re-initializing when recursing */
1795 local_pending_command = NULL;
1796 close_me_head = NULL;
1797 job_list.head = NULL;
1799 #ifdef BB_FEATURE_SH_ENVIRONMENT
1805 if (argv[0] && argv[0][0] == '-') {
1807 prof_input = fopen("/etc/profile", "r");
1809 printf( "Couldn't open file '/etc/profile'\n");
1811 int tmp_fd = fileno(prof_input);
1813 /* Now run the file */
1814 busy_loop(prof_input);
1816 mark_closed(tmp_fd);
1820 while ((opt = getopt(argc_l, argv_l, "cxi")) > 0) {
1824 if (local_pending_command != 0)
1825 error_msg_and_die("multiple -c arguments");
1826 local_pending_command = xstrdup(argv[optind]);
1830 #ifdef BB_FEATURE_SH_ENVIRONMENT
1832 show_x_trace = TRUE;
1842 /* A shell is interactive if the `-i' flag was given, or if all of
1843 * the following conditions are met:
1845 * no arguments remaining or the -s flag given
1846 * standard input is a terminal
1847 * standard output is a terminal
1848 * Refer to Posix.2, the description of the `sh' utility. */
1849 if (argv[optind]==NULL && input==stdin &&
1850 isatty(fileno(stdin)) && isatty(fileno(stdout))) {
1853 if (interactive==TRUE) {
1854 //printf( "optind=%d argv[optind]='%s'\n", optind, argv[optind]);
1855 /* Looks like they want an interactive shell */
1856 printf( "\n\nBusyBox v%s (%s) Built-in shell (lash)\n", BB_VER, BB_BT);
1857 printf( "Enter 'help' for a list of built-in commands.\n\n");
1858 } else if (local_pending_command==NULL) {
1859 //printf( "optind=%d argv[optind]='%s'\n", optind, argv[optind]);
1860 input = xfopen(argv[optind], "r");
1861 mark_open(fileno(input)); /* be lazy, never mark this closed */
1864 /* initialize the cwd -- this is never freed...*/
1865 cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
1866 getcwd(cwd, sizeof(char)*MAX_LINE);
1868 #ifdef BB_FEATURE_CLEAN_UP
1869 atexit(free_memory);
1872 return (busy_loop(input));