2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
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36 * @(#)exec.c 8.4 (Berkeley) 6/8/95
37 * $FreeBSD: src/bin/sh/exec.c,v 1.30 2007/01/11 00:19:00 stefanf Exp $
38 * $DragonFly: src/bin/sh/exec.c,v 1.11 2007/01/14 18:14:39 pavalos Exp $
41 #include <sys/types.h>
49 * When commands are first encountered, they are entered in a hash table.
50 * This ensures that a full path search will not have to be done for them
53 * We should investigate converting to a linear search, even though that
54 * would make the command name "hash" a misnomer.
79 #define CMDTABLESIZE 31 /* should be prime */
80 #define ARB 1 /* actual size determined at run time */
85 struct tblentry *next; /* next entry in hash chain */
86 union param param; /* definition of builtin function */
87 int special; /* flag for special builtin commands */
88 short cmdtype; /* index identifying command */
89 char rehash; /* if set, cd done since entry created */
90 char cmdname[ARB]; /* name of command */
94 STATIC struct tblentry *cmdtable[CMDTABLESIZE];
95 STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */
96 int exerrno = 0; /* Last exec error */
99 STATIC void tryexec(char *, char **, char **);
100 STATIC void printentry(struct tblentry *, int);
101 STATIC struct tblentry *cmdlookup(char *, int);
102 STATIC void delete_cmd_entry(void);
104 extern const char *const parsekwd[];
107 * Exec a program. Never returns. If you change this routine, you may
108 * have to change the find_command routine as well.
112 shellexec(char **argv, char **envp, const char *path, int idx)
117 if (strchr(argv[0], '/') != NULL) {
118 tryexec(argv[0], argv, envp);
122 while ((cmdname = padvance(&path, argv[0])) != NULL) {
123 if (--idx < 0 && pathopt == NULL) {
124 tryexec(cmdname, argv, envp);
125 if (errno != ENOENT && errno != ENOTDIR)
132 /* Map to POSIX errors */
144 if (e == ENOENT || e == ENOTDIR)
145 exerror(EXEXEC, "%s: not found", argv[0]);
146 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
151 tryexec(char *cmd, char **argv, char **envp)
155 execve(cmd, argv, envp);
159 setinputfile(cmd, 0);
160 commandname = arg0 = savestr(argv[0]);
162 exraise(EXSHELLPROC);
169 * Do a path search. The variable path (passed by reference) should be
170 * set to the start of the path before the first call; padvance will update
171 * this value as it proceeds. Successive calls to padvance will return
172 * the possible path expansions in sequence. If an option (indicated by
173 * a percent sign) appears in the path entry then the global variable
174 * pathopt will be set to point to it; otherwise pathopt will be set to
181 padvance(const char **path, const char *name)
191 for (p = start ; *p && *p != ':' && *p != '%' ; p++);
192 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
193 while (stackblocksize() < len)
197 memcpy(q, start, p - start);
205 while (*p && *p != ':') p++;
216 /*** Command hashing code ***/
220 hashcmd(int argc __unused, char **argv __unused)
222 struct tblentry **pp;
223 struct tblentry *cmdp;
226 struct cmdentry entry;
230 while ((c = nextopt("rv")) != '\0') {
233 } else if (c == 'v') {
237 if (*argptr == NULL) {
238 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
239 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
240 if (cmdp->cmdtype == CMDNORMAL)
241 printentry(cmdp, verbose);
246 while ((name = *argptr) != NULL) {
247 if ((cmdp = cmdlookup(name, 0)) != NULL
248 && (cmdp->cmdtype == CMDNORMAL
249 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)))
251 find_command(name, &entry, 1, pathval());
253 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
254 cmdp = cmdlookup(name, 0);
256 printentry(cmdp, verbose);
258 outfmt(&errout, "%s: not found\n", name);
269 printentry(struct tblentry *cmdp, int verbose)
275 if (cmdp->cmdtype == CMDNORMAL) {
276 idx = cmdp->param.index;
279 name = padvance(&path, cmdp->cmdname);
281 } while (--idx >= 0);
283 } else if (cmdp->cmdtype == CMDBUILTIN) {
284 out1fmt("builtin %s", cmdp->cmdname);
285 } else if (cmdp->cmdtype == CMDFUNCTION) {
286 out1fmt("function %s", cmdp->cmdname);
289 name = commandtext(cmdp->param.func);
297 error("internal error: cmdtype %d", cmdp->cmdtype);
308 * Resolve a command name. If you change this routine, you may have to
309 * change the shellexec routine as well.
313 find_command(char *name, struct cmdentry *entry, int printerr, const char *path)
315 struct tblentry *cmdp;
324 /* If name contains a slash, don't use the hash table */
325 if (strchr(name, '/') != NULL) {
326 entry->cmdtype = CMDNORMAL;
331 /* If name is in the table, and not invalidated by cd, we're done */
332 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0)
335 /* If %builtin not in path, check for builtin next */
336 if (builtinloc < 0 && (i = find_builtin(name, &spec)) >= 0) {
338 cmdp = cmdlookup(name, 1);
339 cmdp->cmdtype = CMDBUILTIN;
340 cmdp->param.index = i;
341 cmdp->special = spec;
346 /* We have to search path. */
347 prev = -1; /* where to start */
348 if (cmdp) { /* doing a rehash */
349 if (cmdp->cmdtype == CMDBUILTIN)
352 prev = cmdp->param.index;
358 while ((fullname = padvance(&path, name)) != NULL) {
362 if (prefix("builtin", pathopt)) {
363 if ((i = find_builtin(name, &spec)) < 0)
366 cmdp = cmdlookup(name, 1);
367 cmdp->cmdtype = CMDBUILTIN;
368 cmdp->param.index = i;
369 cmdp->special = spec;
372 } else if (prefix("func", pathopt)) {
375 goto loop; /* ignore unimplemented options */
378 /* if rehash, don't redo absolute path names */
379 if (fullname[0] == '/' && idx <= prev) {
382 TRACE(("searchexec \"%s\": no change\n", name));
385 if (stat(fullname, &statb) < 0) {
386 if (errno != ENOENT && errno != ENOTDIR)
390 e = EACCES; /* if we fail, this will be the error */
391 if (!S_ISREG(statb.st_mode))
393 if (pathopt) { /* this is a %func directory */
394 stalloc(strlen(fullname) + 1);
395 readcmdfile(fullname);
396 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
397 error("%s not defined in %s", name, fullname);
402 if (statb.st_uid == geteuid()) {
403 if ((statb.st_mode & 0100) == 0)
405 } else if (statb.st_gid == getegid()) {
406 if ((statb.st_mode & 010) == 0)
409 if ((statb.st_mode & 01) == 0)
413 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
415 cmdp = cmdlookup(name, 1);
416 cmdp->cmdtype = CMDNORMAL;
417 cmdp->param.index = idx;
422 /* We failed. If there was an entry for this command, delete it */
426 if (e == ENOENT || e == ENOTDIR)
427 outfmt(out2, "%s: not found\n", name);
429 outfmt(out2, "%s: %s\n", name, strerror(e));
431 entry->cmdtype = CMDUNKNOWN;
437 entry->cmdtype = cmdp->cmdtype;
438 entry->u = cmdp->param;
439 entry->special = cmdp->special;
441 entry->cmdtype = CMDUNKNOWN;
447 * Search the table of builtin commands.
451 find_builtin(char *name, int *special)
453 const struct builtincmd *bp;
455 for (bp = builtincmd ; bp->name ; bp++) {
456 if (*bp->name == *name && equal(bp->name, name)) {
457 *special = bp->special;
467 * Called when a cd is done. Marks all commands so the next time they
468 * are executed they will be rehashed.
474 struct tblentry **pp;
475 struct tblentry *cmdp;
477 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
478 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
479 if (cmdp->cmdtype == CMDNORMAL
480 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
489 * Called before PATH is changed. The argument is the new value of PATH;
490 * pathval() still returns the old value at this point. Called with
495 changepath(const char *newval)
497 const char *old, *new;
504 firstchange = 9999; /* assume no change */
510 if ((*old == '\0' && *new == ':')
511 || (*old == ':' && *new == '\0'))
513 old = new; /* ignore subsequent differences */
517 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
524 if (builtinloc < 0 && bltin >= 0)
525 builtinloc = bltin; /* zap builtins */
526 if (builtinloc >= 0 && bltin < 0)
528 clearcmdentry(firstchange);
534 * Clear out command entries. The argument specifies the first entry in
535 * PATH which has changed.
539 clearcmdentry(int firstchange)
541 struct tblentry **tblp;
542 struct tblentry **pp;
543 struct tblentry *cmdp;
546 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
548 while ((cmdp = *pp) != NULL) {
549 if ((cmdp->cmdtype == CMDNORMAL &&
550 cmdp->param.index >= firstchange)
551 || (cmdp->cmdtype == CMDBUILTIN &&
552 builtinloc >= firstchange)) {
565 * Delete all functions.
569 MKINIT void deletefuncs(void);
579 struct tblentry **tblp;
580 struct tblentry **pp;
581 struct tblentry *cmdp;
584 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
586 while ((cmdp = *pp) != NULL) {
587 if (cmdp->cmdtype == CMDFUNCTION) {
589 freefunc(cmdp->param.func);
602 * Locate a command in the command hash table. If "add" is nonzero,
603 * add the command to the table if it is not already present. The
604 * variable "lastcmdentry" is set to point to the address of the link
605 * pointing to the entry, so that delete_cmd_entry can delete the
609 STATIC struct tblentry **lastcmdentry;
612 STATIC struct tblentry *
613 cmdlookup(char *name, int add)
617 struct tblentry *cmdp;
618 struct tblentry **pp;
625 pp = &cmdtable[hashval % CMDTABLESIZE];
626 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
627 if (equal(cmdp->cmdname, name))
631 if (add && cmdp == NULL) {
633 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
636 cmdp->cmdtype = CMDUNKNOWN;
638 strcpy(cmdp->cmdname, name);
646 * Delete the command entry returned on the last lookup.
650 delete_cmd_entry(void)
652 struct tblentry *cmdp;
655 cmdp = *lastcmdentry;
656 *lastcmdentry = cmdp->next;
664 * Add a new command entry, replacing any existing command entry for
669 addcmdentry(char *name, struct cmdentry *entry)
671 struct tblentry *cmdp;
674 cmdp = cmdlookup(name, 1);
675 if (cmdp->cmdtype == CMDFUNCTION) {
676 freefunc(cmdp->param.func);
678 cmdp->cmdtype = entry->cmdtype;
679 cmdp->param = entry->u;
685 * Define a shell function.
689 defun(char *name, union node *func)
691 struct cmdentry entry;
694 entry.cmdtype = CMDFUNCTION;
695 entry.u.func = copyfunc(func);
696 addcmdentry(name, &entry);
702 * Delete a function if it exists.
706 unsetfunc(char *name)
708 struct tblentry *cmdp;
710 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
711 freefunc(cmdp->param.func);
718 * Shared code for the following builtin commands:
719 * type, command -v, command -V
723 typecmd_impl(int argc, char **argv, int cmd)
725 struct cmdentry entry;
726 struct tblentry *cmdp;
727 const char * const *pp;
732 for (i = 1; i < argc; i++) {
733 if (cmd != TYPECMD_SMALLV)
736 /* First look at the keywords */
737 for (pp = parsekwd; *pp; pp++)
738 if (**pp == *argv[i] && equal(*pp, argv[i]))
742 if (cmd == TYPECMD_SMALLV)
743 out1fmt("%s\n", argv[i]);
745 out1str(" is a shell keyword\n");
749 /* Then look at the aliases */
750 if ((ap = lookupalias(argv[i], 1)) != NULL) {
751 if (cmd == TYPECMD_SMALLV)
752 out1fmt("alias %s='%s'\n", argv[i], ap->val);
754 out1fmt(" is an alias for %s\n", ap->val);
758 /* Then check if it is a tracked alias */
759 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
760 entry.cmdtype = cmdp->cmdtype;
761 entry.u = cmdp->param;
764 /* Finally use brute force */
765 find_command(argv[i], &entry, 0, pathval());
768 switch (entry.cmdtype) {
770 if (strchr(argv[i], '/') == NULL) {
771 const char *path = pathval();
773 int j = entry.u.index;
775 name = padvance(&path, argv[i]);
778 if (cmd == TYPECMD_SMALLV)
779 out1fmt("%s\n", name);
781 out1fmt(" is%s %s\n",
782 (cmdp && cmd == TYPECMD_TYPE) ?
783 " a tracked alias for" : "",
786 if (access(argv[i], X_OK) == 0) {
787 if (cmd == TYPECMD_SMALLV)
788 out1fmt("%s\n", argv[i]);
790 out1fmt(" is %s\n", argv[i]);
792 if (cmd != TYPECMD_SMALLV)
801 if (cmd == TYPECMD_SMALLV)
802 out1fmt("%s\n", argv[i]);
804 out1str(" is a shell function\n");
808 if (cmd == TYPECMD_SMALLV)
809 out1fmt("%s\n", argv[i]);
811 out1str(" is a shell builtin\n");
815 if (cmd != TYPECMD_SMALLV)
816 out1str(": not found\n");
825 * Locate and print what a word is...
829 typecmd(int argc, char **argv)
831 return typecmd_impl(argc, argv, TYPECMD_TYPE);