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;
919 const char *out_of_space = "out of space during expansion";
922 /* get rid of the terminating \n */
925 #ifdef BB_FEATURE_SH_ENVIRONMENT
928 #if ( (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) ) || defined (__UCLIBC__)
929 /* This first part uses wordexp() which is a wonderful C lib
930 * function which expands nearly everything. */
931 retval = wordexp (command, &expand_result, 0);
932 if (retval == WRDE_NOSPACE) {
933 /* Mem may have been allocated... */
934 wordfree (&expand_result);
935 error_msg(out_of_space);
939 /* Some other error. */
940 error_msg("syntax error");
944 /* Convert from char** (one word per string) to a simple char*,
945 * but don't overflow command which is BUFSIZ in length */
947 while (i < expand_result.we_wordc && total_length < BUFSIZ) {
948 length=strlen(expand_result.we_wordv[i])+1;
949 if (BUFSIZ-total_length-length <= 0) {
950 error_msg(out_of_space);
953 strcat(command+total_length, expand_result.we_wordv[i++]);
954 strcat(command+total_length, " ");
955 total_length+=length;
957 wordfree (&expand_result);
960 /* Ok. They don't have a recent glibc and they don't have uClibc. Chances
961 * are about 100% they don't have wordexp(). So instead the best we can do
962 * is use glob and then fixup environment variables and such ourselves.
963 * This is better then nothing, but certainly not perfect */
965 /* It turns out that glob is very stupid. We have to feed it one word at a
966 * time since it can't cope with a full string. Here we convert command
967 * (char*) into cmd (char**, one word per string) */
970 int flags = GLOB_NOCHECK|GLOB_BRACE|GLOB_TILDE;
972 /* We need a clean copy, so strsep can mess up the copy while
973 * we write stuff into the original (in a minute) */
974 char * cmd = strdup(command);
976 for (tmpcmd = cmd; (tmpcmd = strsep(&cmd, " \t")) != NULL;) {
979 retval = glob(tmpcmd, flags, NULL, &expand_result);
980 if (retval == GLOB_NOSPACE) {
981 /* Mem may have been allocated... */
982 globfree (&expand_result);
983 error_msg(out_of_space);
985 } else if (retval != 0) {
986 /* Some other error. GLOB_NOMATCH shouldn't
987 * happen because of the GLOB_NOCHECK flag in
989 error_msg("syntax error");
992 /* Convert from char** (one word per string) to a simple char*,
993 * but don't overflow command which is BUFSIZ in length */
994 for (i=0; i < expand_result.gl_pathc; i++) {
995 length=strlen(expand_result.gl_pathv[i])+1;
996 if (BUFSIZ-total_length-length <= 0) {
997 error_msg(out_of_space);
1000 strcat(command+total_length, expand_result.gl_pathv[i]);
1001 strcat(command+total_length, " ");
1002 total_length+=length;
1004 globfree (&expand_result);
1013 /* Now do the shell variable substitutions which
1014 * wordexp can't do for us, namely $? and $! */
1016 while((dst = strchr(src,'$')) != NULL){
1020 var = itoa(last_return_code);
1023 if (last_bg_pid==-1)
1026 var = itoa(last_bg_pid);
1028 /* Everything else like $$, $#, $[0-9], etc should all be
1029 * expanded by wordexp(), so we can in theory skip that stuff
1030 * here, but just to be on the safe side (i.e. since uClibc
1031 * wordexp doesn't do this stuff yet), lets leave it in for
1034 var = itoa(getpid());
1039 case '0':case '1':case '2':case '3':case '4':
1040 case '5':case '6':case '7':case '8':case '9':
1042 int index=*(dst + 1)-48;
1043 if (index >= argc) {
1053 /* a single character construction was found, and
1054 * already handled in the case statement */
1057 /* Looks like an environment variable */
1059 int num_skip_chars=1;
1060 int dstlen = strlen(dst);
1061 /* Is this a ${foo} type variable? */
1062 if (dstlen >=2 && *(dst+1) == '{') {
1063 src=strchr(dst+1, '}');
1066 src=strpbrk(dst+1, " \t~`!$^&*()=|\\[];\"'<>?./");
1072 *src='\0'; /* temporary */
1073 var = getenv(dst + num_skip_chars);
1075 if (num_skip_chars==2) {
1080 /* Seems we got an un-expandable variable. So delete it. */
1084 int subst_len = strlen(var);
1085 int trail_len = strlen(src);
1086 if (dst+subst_len+trail_len >= command+BUFSIZ) {
1087 error_msg(out_of_space);
1090 /* Move stuff to the end of the string to accommodate
1091 * filling the created gap with the new stuff */
1092 memmove(dst+subst_len, src, trail_len);
1093 *(dst+subst_len+trail_len)='\0';
1094 /* Now copy in the new stuff */
1095 memcpy(dst, var, subst_len);
1096 src = dst+subst_len;
1104 /* Return cmd->num_progs as 0 if no command is present (e.g. an empty
1105 line). If a valid command is found, command_ptr is set to point to
1106 the beginning of the next command (if the original command had more
1107 then one job associated with it) or NULL if no more commands are
1109 static int parse_command(char **command_ptr, struct job *job, int *inbg)
1112 char *return_command = NULL;
1113 char *src, *buf, *chptr;
1120 struct child_prog *prog;
1122 /* skip leading white space */
1123 while (**command_ptr && isspace(**command_ptr))
1126 /* this handles empty lines or leading '#' characters */
1127 if (!**command_ptr || (**command_ptr == '#')) {
1134 job->progs = xmalloc(sizeof(*job->progs));
1136 /* We set the argv elements to point inside of this string. The
1137 memory is freed by free_job(). Allocate twice the original
1138 length in case we need to quote every single character.
1140 Getting clean memory relieves us of the task of NULL
1141 terminating things and makes the rest of this look a bit
1142 cleaner (though it is, admittedly, a tad less efficient) */
1143 job->cmdbuf = command = xcalloc(2*strlen(*command_ptr) + 1, sizeof(char));
1147 prog->num_redirects = 0;
1148 prog->redirects = NULL;
1149 prog->is_stopped = 0;
1153 prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1154 prog->argv[0] = job->cmdbuf;
1158 while (*src && !done) {
1159 if (quote == *src) {
1165 error_msg("character expected after \\");
1170 /* in shell, "\'" should yield \' */
1171 if (*src != quote) {
1175 } else if (*src == '*' || *src == '?' || *src == '[' ||
1176 *src == ']') *buf++ = '\\';
1178 } else if (isspace(*src)) {
1179 if (*prog->argv[argc_l]) {
1181 /* +1 here leaves room for the NULL which ends argv */
1182 if ((argc_l + 1) == argv_alloced) {
1184 prog->argv = xrealloc(prog->argv,
1185 sizeof(*prog->argv) *
1188 prog->argv[argc_l] = buf;
1197 case '#': /* comment */
1204 case '>': /* redirects */
1206 i = prog->num_redirects++;
1207 prog->redirects = xrealloc(prog->redirects,
1208 sizeof(*prog->redirects) *
1211 prog->redirects[i].fd = -1;
1212 if (buf != prog->argv[argc_l]) {
1213 /* the stuff before this character may be the file number
1215 prog->redirects[i].fd =
1216 strtol(prog->argv[argc_l], &chptr, 10);
1218 if (*chptr && *prog->argv[argc_l]) {
1220 prog->argv[argc_l] = buf;
1224 if (prog->redirects[i].fd == -1) {
1226 prog->redirects[i].fd = 1;
1228 prog->redirects[i].fd = 0;
1231 if (*src++ == '>') {
1233 prog->redirects[i].type =
1234 REDIRECT_APPEND, src++;
1236 prog->redirects[i].type = REDIRECT_OVERWRITE;
1238 prog->redirects[i].type = REDIRECT_INPUT;
1241 /* This isn't POSIX sh compliant. Oh well. */
1243 while (isspace(*chptr))
1247 error_msg("file name expected after %c", *src);
1253 prog->redirects[i].filename = buf;
1254 while (*chptr && !isspace(*chptr))
1257 src = chptr - 1; /* we src++ later */
1258 prog->argv[argc_l] = ++buf;
1261 case '|': /* pipe */
1262 /* finish this command */
1263 if (*prog->argv[argc_l])
1266 error_msg("empty command in pipe");
1271 prog->argv[argc_l] = NULL;
1273 /* and start the next */
1275 job->progs = xrealloc(job->progs,
1276 sizeof(*job->progs) * job->num_progs);
1277 prog = job->progs + (job->num_progs - 1);
1278 prog->num_redirects = 0;
1279 prog->redirects = NULL;
1280 prog->is_stopped = 0;
1285 prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1286 prog->argv[0] = ++buf;
1289 while (*src && isspace(*src))
1293 error_msg("empty command in pipe");
1298 src--; /* we'll ++ it at the end of the loop */
1302 case '&': /* background */
1304 case ';': /* multiple commands */
1306 return_command = *command_ptr + (src - *command_ptr) + 1;
1309 #ifdef BB_FEATURE_SH_BACKTICKS
1311 /* Exec a backtick-ed command */
1312 /* Besides any previous brokenness, I have not
1313 * updated backtick handling for close_me support.
1314 * I don't know if it needs it or not. -- LRD */
1316 char* charptr1=NULL, *charptr2;
1319 struct jobset njob_list = { NULL, NULL };
1323 ptr=strchr(++src, '`');
1325 fprintf(stderr, "Unmatched '`' in command\n");
1330 /* Make some space to hold just the backticked command */
1331 charptr1 = charptr2 = xmalloc(1+ptr-src);
1332 memcpy(charptr1, src, ptr-src);
1333 charptr1[ptr-src] = '\0';
1334 newjob = xmalloc(sizeof(struct job));
1335 newjob->job_list = &njob_list;
1336 /* Now parse and run the backticked command */
1337 if (!parse_command(&charptr1, newjob, inbg)
1338 && newjob->num_progs) {
1340 run_command(newjob, 0, pipefd);
1342 checkjobs(job->job_list);
1343 free_job(newjob); /* doesn't actually free newjob,
1344 looks like a memory leak */
1347 /* Make a copy of any stuff left over in the command
1348 * line after the second backtick */
1349 charptr2 = xmalloc(strlen(ptr)+1);
1350 memcpy(charptr2, ptr+1, strlen(ptr));
1353 /* Copy the output from the backtick-ed command into the
1354 * command line, making extra room as needed */
1356 charptr1 = xmalloc(BUFSIZ);
1357 while ( (size=full_read(pipefd[0], charptr1, BUFSIZ-1)) >0) {
1358 int newsize=src - *command_ptr + size + 1 + strlen(charptr2);
1359 if (newsize > BUFSIZ) {
1360 *command_ptr=xrealloc(*command_ptr, newsize);
1362 memcpy(src, charptr1, size);
1370 /* Now paste into the *command_ptr all the stuff
1371 * leftover after the second backtick */
1372 memcpy(src, charptr2, strlen(charptr2)+1);
1375 /* Now recursively call parse_command to deal with the new
1376 * and improved version of the command line with the backtick
1377 * results expanded in place... */
1379 struct jobset *jl=job->job_list;
1383 return(parse_command(command_ptr, job, inbg));
1386 #endif // BB_FEATURE_SH_BACKTICKS
1391 /* This is currently a little broken... */
1392 #ifdef HANDLE_CONTINUATION_CHARS
1393 /* They fed us a continuation char, so continue reading stuff
1394 * on the next line, then tack that onto the end of the current
1398 printf("erik: found a continue char at EOL...\n");
1399 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1400 if (get_command(input, command)) {
1401 error_msg("character expected after \\");
1406 newsize = strlen(*command_ptr) + strlen(command) + 2;
1407 if (newsize > BUFSIZ) {
1408 printf("erik: doing realloc\n");
1409 *command_ptr=xrealloc(*command_ptr, newsize);
1411 printf("erik: A: *command_ptr='%s'\n", *command_ptr);
1412 memcpy(--src, command, strlen(command));
1413 printf("erik: B: *command_ptr='%s'\n", *command_ptr);
1417 error_msg("character expected after \\");
1423 if (*src == '*' || *src == '[' || *src == ']'
1424 || *src == '?') *buf++ = '\\';
1433 if (*prog->argv[argc_l]) {
1440 prog->argv[argc_l] = NULL;
1442 if (!return_command) {
1443 job->text = xmalloc(strlen(*command_ptr) + 1);
1444 strcpy(job->text, *command_ptr);
1446 /* This leaves any trailing spaces, which is a bit sloppy */
1447 count = return_command - *command_ptr;
1448 job->text = xmalloc(count + 1);
1449 strncpy(job->text, *command_ptr, count);
1450 job->text[count] = '\0';
1453 *command_ptr = return_command;
1458 /* Run the child_prog, no matter what kind of command it uses.
1460 static int pseudo_exec(struct child_prog *child)
1462 struct built_in_command *x;
1463 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1467 /* Check if the command matches any of the non-forking builtins.
1468 * Depending on context, this might be redundant. But it's
1469 * easier to waste a few CPU cycles than it is to figure out
1470 * if this is one of those cases.
1472 for (x = bltins; x->cmd; x++) {
1473 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1474 exit(x->function(child));
1478 /* Check if the command matches any of the forking builtins. */
1479 for (x = bltins_forking; x->cmd; x++) {
1480 if (strcmp(child->argv[0], x->cmd) == 0) {
1482 exit (x->function(child));
1485 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1486 /* Check if the command matches any busybox internal
1487 * commands ("applets") here. Following discussions from
1488 * November 2000 on busybox@opensource.lineo.com, don't use
1489 * get_last_path_component(). This way explicit (with
1490 * slashes) filenames will never be interpreted as an
1491 * applet, just like with builtins. This way the user can
1492 * override an applet with an explicit filename reference.
1493 * The only downside to this change is that an explicit
1494 * /bin/foo invocation will fork and exec /bin/foo, even if
1495 * /bin/foo is a symlink to busybox.
1497 name = child->argv[0];
1499 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1500 /* If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then
1501 * if you run /bin/cat, it will use BusyBox cat even if
1502 * /bin/cat exists on the filesystem and is _not_ busybox.
1503 * Some systems want this, others do not. Choose wisely. :-)
1505 name = get_last_path_component(name);
1509 char** argv=child->argv;
1511 for(argc_l=0;*argv!=NULL; argv++, argc_l++);
1513 run_applet_by_name(name, argc_l, child->argv);
1517 execvp(child->argv[0], child->argv);
1518 perror_msg_and_die("%s", child->argv[0]);
1521 static void insert_job(struct job *newjob, int inbg)
1524 struct jobset *job_list=newjob->job_list;
1526 /* find the ID for thejob to use */
1528 for (thejob = job_list->head; thejob; thejob = thejob->next)
1529 if (thejob->jobid >= newjob->jobid)
1530 newjob->jobid = thejob->jobid + 1;
1532 /* add thejob to the list of running jobs */
1533 if (!job_list->head) {
1534 thejob = job_list->head = xmalloc(sizeof(*thejob));
1536 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1537 thejob->next = xmalloc(sizeof(*thejob));
1538 thejob = thejob->next;
1541 *thejob = *newjob; /* physically copy the struct job */
1542 thejob->next = NULL;
1543 thejob->running_progs = thejob->num_progs;
1544 thejob->stopped_progs = 0;
1547 /* we don't wait for background thejobs to return -- append it
1548 to the list of backgrounded thejobs and leave it alone */
1549 printf("[%d] %d\n", thejob->jobid,
1550 newjob->progs[newjob->num_progs - 1].pid);
1551 #ifdef BB_FEATURE_SH_ENVIRONMENT
1552 last_bg_pid=newjob->progs[newjob->num_progs - 1].pid;
1555 newjob->job_list->fg = thejob;
1557 /* move the new process group into the foreground */
1558 /* suppress messages when run from /linuxrc mag@sysgo.de */
1559 if (tcsetpgrp(0, newjob->pgrp) && errno != ENOTTY)
1560 perror_msg("tcsetpgrp");
1564 static int run_command(struct job *newjob, int inbg, int outpipe[2])
1566 /* struct job *thejob; */
1568 int nextin, nextout;
1569 int pipefds[2]; /* pipefd[0] is for reading */
1570 struct built_in_command *x;
1571 struct child_prog *child;
1573 nextin = 0, nextout = 1;
1574 for (i = 0; i < newjob->num_progs; i++) {
1575 child = & (newjob->progs[i]);
1577 if ((i + 1) < newjob->num_progs) {
1578 if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1579 nextout = pipefds[1];
1581 if (outpipe[1]!=-1) {
1582 nextout = outpipe[1];
1588 #ifdef BB_FEATURE_SH_ENVIRONMENT
1589 if (show_x_trace==TRUE) {
1592 for (j = 0; child->argv[j]; j++) {
1594 fputs(child->argv[j], stderr);
1596 fputc('\n', stderr);
1600 /* Check if the command matches any non-forking builtins,
1601 * but only if this is a simple command.
1602 * Non-forking builtins within pipes have to fork anyway,
1603 * and are handled in pseudo_exec. "echo foo | read bar"
1604 * is doomed to failure, and doesn't work on bash, either.
1606 if (newjob->num_progs == 1) {
1607 for (x = bltins; x->cmd; x++) {
1608 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1609 int squirrel[] = {-1, -1, -1};
1611 setup_redirects(child, squirrel);
1612 rcode = x->function(child);
1613 restore_redirects(squirrel);
1619 if (!(child->pid = fork())) {
1620 signal(SIGTTOU, SIG_DFL);
1624 if (outpipe[1]!=-1) {
1634 dup2(nextout, 2); /* Really? */
1639 /* explicit redirects override pipes */
1640 setup_redirects(child,NULL);
1644 if (outpipe[1]!=-1) {
1648 /* put our child in the process group whose leader is the
1649 first process in this pipe */
1650 setpgid(child->pid, newjob->progs[0].pid);
1656 /* If there isn't another process, nextin is garbage
1657 but it doesn't matter */
1658 nextin = pipefds[0];
1661 newjob->pgrp = newjob->progs[0].pid;
1663 insert_job(newjob, inbg);
1668 static int busy_loop(FILE * input)
1671 char *next_command = NULL;
1677 newjob.job_list = &job_list;
1678 newjob.job_context = DEFAULT_CONTEXT;
1680 /* save current owner of TTY so we can restore it on exit */
1681 parent_pgrp = tcgetpgrp(0);
1683 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1685 /* don't pay any attention to this signal; it just confuses
1686 things and isn't really meant for shells anyway */
1687 signal(SIGTTOU, SIG_IGN);
1691 /* no job is in the foreground */
1693 /* see if any background processes have exited */
1694 checkjobs(&job_list);
1696 if (!next_command) {
1697 if (get_command(input, command))
1699 next_command = command;
1702 if (expand_arguments(next_command) == FALSE) {
1704 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1705 next_command = NULL;
1709 if (!parse_command(&next_command, &newjob, &inbg) &&
1711 int pipefds[2] = {-1,-1};
1712 debug_printf( "job=%p being fed to run_command by busy_loop()'\n", &newjob);
1713 run_command(&newjob, inbg, pipefds);
1717 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1718 next_command = NULL;
1721 /* a job is running in the foreground; wait for it */
1723 while (!job_list.fg->progs[i].pid ||
1724 job_list.fg->progs[i].is_stopped == 1) i++;
1726 if (waitpid(job_list.fg->progs[i].pid, &status, WUNTRACED)<0)
1727 perror_msg_and_die("waitpid(%d)",job_list.fg->progs[i].pid);
1729 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1730 /* the child exited */
1731 job_list.fg->running_progs--;
1732 job_list.fg->progs[i].pid = 0;
1734 #ifdef BB_FEATURE_SH_ENVIRONMENT
1735 last_return_code=WEXITSTATUS(status);
1736 debug_printf("'%s' exited -- return code %d\n",
1737 job_list.fg->text, last_return_code);
1739 if (!job_list.fg->running_progs) {
1741 remove_job(&job_list, job_list.fg);
1745 /* the child was stopped */
1746 job_list.fg->stopped_progs++;
1747 job_list.fg->progs[i].is_stopped = 1;
1749 if (job_list.fg->stopped_progs == job_list.fg->running_progs) {
1750 printf("\n" JOB_STATUS_FORMAT, job_list.fg->jobid,
1751 "Stopped", job_list.fg->text);
1757 /* move the shell to the foreground */
1758 /* suppress messages when run from /linuxrc mag@sysgo.de */
1759 if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
1760 perror_msg("tcsetpgrp");
1766 /* return controlling TTY back to parent process group before exiting */
1767 if (tcsetpgrp(0, parent_pgrp))
1768 perror_msg("tcsetpgrp");
1770 /* return exit status if called with "-c" */
1771 if (input == NULL && WIFEXITED(status))
1772 return WEXITSTATUS(status);
1778 #ifdef BB_FEATURE_CLEAN_UP
1779 void free_memory(void)
1783 if (local_pending_command)
1784 free(local_pending_command);
1786 if (job_list.fg && !job_list.fg->running_progs) {
1787 remove_job(&job_list, job_list.fg);
1793 int shell_main(int argc_l, char **argv_l)
1795 int opt, interactive=FALSE;
1796 FILE *input = stdin;
1800 /* These variables need re-initializing when recursing */
1803 local_pending_command = NULL;
1804 close_me_head = NULL;
1805 job_list.head = NULL;
1807 #ifdef BB_FEATURE_SH_ENVIRONMENT
1813 if (argv[0] && argv[0][0] == '-') {
1815 prof_input = fopen("/etc/profile", "r");
1817 printf( "Couldn't open file '/etc/profile'\n");
1819 int tmp_fd = fileno(prof_input);
1821 /* Now run the file */
1822 busy_loop(prof_input);
1824 mark_closed(tmp_fd);
1828 while ((opt = getopt(argc_l, argv_l, "cxi")) > 0) {
1832 if (local_pending_command != 0)
1833 error_msg_and_die("multiple -c arguments");
1834 local_pending_command = xstrdup(argv[optind]);
1838 #ifdef BB_FEATURE_SH_ENVIRONMENT
1840 show_x_trace = TRUE;
1850 /* A shell is interactive if the `-i' flag was given, or if all of
1851 * the following conditions are met:
1853 * no arguments remaining or the -s flag given
1854 * standard input is a terminal
1855 * standard output is a terminal
1856 * Refer to Posix.2, the description of the `sh' utility. */
1857 if (argv[optind]==NULL && input==stdin &&
1858 isatty(fileno(stdin)) && isatty(fileno(stdout))) {
1861 if (interactive==TRUE) {
1862 //printf( "optind=%d argv[optind]='%s'\n", optind, argv[optind]);
1863 /* Looks like they want an interactive shell */
1864 printf( "\n\nBusyBox v%s (%s) Built-in shell (lash)\n", BB_VER, BB_BT);
1865 printf( "Enter 'help' for a list of built-in commands.\n\n");
1866 } else if (local_pending_command==NULL) {
1867 //printf( "optind=%d argv[optind]='%s'\n", optind, argv[optind]);
1868 input = xfopen(argv[optind], "r");
1869 mark_open(fileno(input)); /* be lazy, never mark this closed */
1872 /* initialize the cwd -- this is never freed...*/
1873 cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
1874 getcwd(cwd, sizeof(char)*MAX_LINE);
1876 #ifdef BB_FEATURE_CLEAN_UP
1877 atexit(free_memory);
1880 return (busy_loop(input));