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
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 static char sccsid[] = "@(#)exec.c 8.4 (Berkeley) 6/8/95";
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD: src/bin/sh/exec.c,v 1.14.2.4 2002/08/27 01:36:28 tjr Exp $");
45 #include <sys/types.h>
53 * When commands are first encountered, they are entered in a hash table.
54 * This ensures that a full path search will not have to be done for them
57 * We should investigate converting to a linear search, even though that
58 * would make the command name "hash" a misnomer.
83 #define CMDTABLESIZE 31 /* should be prime */
84 #define ARB 1 /* actual size determined at run time */
89 struct tblentry *next; /* next entry in hash chain */
90 union param param; /* definition of builtin function */
91 short cmdtype; /* index identifying command */
92 char rehash; /* if set, cd done since entry created */
93 char cmdname[ARB]; /* name of command */
97 STATIC struct tblentry *cmdtable[CMDTABLESIZE];
98 STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */
99 int exerrno = 0; /* Last exec error */
102 STATIC void tryexec(char *, char **, char **);
103 STATIC void printentry(struct tblentry *, int);
104 STATIC struct tblentry *cmdlookup(char *, int);
105 STATIC void delete_cmd_entry(void);
110 * Exec a program. Never returns. If you change this routine, you may
111 * have to change the find_command routine as well.
115 shellexec(char **argv, char **envp, char *path, int index)
120 if (strchr(argv[0], '/') != NULL) {
121 tryexec(argv[0], argv, envp);
125 while ((cmdname = padvance(&path, argv[0])) != NULL) {
126 if (--index < 0 && pathopt == NULL) {
127 tryexec(cmdname, argv, envp);
128 if (errno != ENOENT && errno != ENOTDIR)
135 /* Map to POSIX errors */
147 exerror(EXEXEC, "%s: %s", argv[0], errmsg(e, E_EXEC));
152 tryexec(char *cmd, char **argv, char **envp)
156 execve(cmd, argv, envp);
160 setinputfile(cmd, 0);
161 commandname = arg0 = savestr(argv[0]);
163 exraise(EXSHELLPROC);
170 * Do a path search. The variable path (passed by reference) should be
171 * set to the start of the path before the first call; padvance will update
172 * this value as it proceeds. Successive calls to padvance will return
173 * the possible path expansions in sequence. If an option (indicated by
174 * a percent sign) appears in the path entry then the global variable
175 * pathopt will be set to point to it; otherwise pathopt will be set to
182 padvance(char **path, 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 index = cmdp->param.index;
279 name = padvance(&path, cmdp->cmdname);
281 } while (--index >= 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, char *path)
315 struct tblentry *cmdp;
323 /* If name contains a slash, don't use the hash table */
324 if (strchr(name, '/') != NULL) {
325 entry->cmdtype = CMDNORMAL;
330 /* If name is in the table, and not invalidated by cd, we're done */
331 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0)
334 /* If %builtin not in path, check for builtin next */
335 if (builtinloc < 0 && (i = find_builtin(name)) >= 0) {
337 cmdp = cmdlookup(name, 1);
338 cmdp->cmdtype = CMDBUILTIN;
339 cmdp->param.index = i;
344 /* We have to search path. */
345 prev = -1; /* where to start */
346 if (cmdp) { /* doing a rehash */
347 if (cmdp->cmdtype == CMDBUILTIN)
350 prev = cmdp->param.index;
356 while ((fullname = padvance(&path, name)) != NULL) {
360 if (prefix("builtin", pathopt)) {
361 if ((i = find_builtin(name)) < 0)
364 cmdp = cmdlookup(name, 1);
365 cmdp->cmdtype = CMDBUILTIN;
366 cmdp->param.index = i;
369 } else if (prefix("func", pathopt)) {
372 goto loop; /* ignore unimplemented options */
375 /* if rehash, don't redo absolute path names */
376 if (fullname[0] == '/' && index <= prev) {
379 TRACE(("searchexec \"%s\": no change\n", name));
382 if (stat(fullname, &statb) < 0) {
383 if (errno != ENOENT && errno != ENOTDIR)
387 e = EACCES; /* if we fail, this will be the error */
388 if (!S_ISREG(statb.st_mode))
390 if (pathopt) { /* this is a %func directory */
391 stalloc(strlen(fullname) + 1);
392 readcmdfile(fullname);
393 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
394 error("%s not defined in %s", name, fullname);
399 if (statb.st_uid == geteuid()) {
400 if ((statb.st_mode & 0100) == 0)
402 } else if (statb.st_gid == getegid()) {
403 if ((statb.st_mode & 010) == 0)
406 if ((statb.st_mode & 01) == 0)
410 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
412 cmdp = cmdlookup(name, 1);
413 cmdp->cmdtype = CMDNORMAL;
414 cmdp->param.index = index;
419 /* We failed. If there was an entry for this command, delete it */
423 outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC));
424 entry->cmdtype = CMDUNKNOWN;
429 entry->cmdtype = cmdp->cmdtype;
430 entry->u = cmdp->param;
436 * Search the table of builtin commands.
440 find_builtin(char *name)
442 const struct builtincmd *bp;
444 for (bp = builtincmd ; bp->name ; bp++) {
445 if (*bp->name == *name && equal(bp->name, name))
454 * Called when a cd is done. Marks all commands so the next time they
455 * are executed they will be rehashed.
461 struct tblentry **pp;
462 struct tblentry *cmdp;
464 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
465 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
466 if (cmdp->cmdtype == CMDNORMAL
467 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
476 * Called before PATH is changed. The argument is the new value of PATH;
477 * pathval() still returns the old value at this point. Called with
482 changepath(const char *newval)
484 const char *old, *new;
491 firstchange = 9999; /* assume no change */
497 if ((*old == '\0' && *new == ':')
498 || (*old == ':' && *new == '\0'))
500 old = new; /* ignore subsequent differences */
504 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
511 if (builtinloc < 0 && bltin >= 0)
512 builtinloc = bltin; /* zap builtins */
513 if (builtinloc >= 0 && bltin < 0)
515 clearcmdentry(firstchange);
521 * Clear out command entries. The argument specifies the first entry in
522 * PATH which has changed.
526 clearcmdentry(int firstchange)
528 struct tblentry **tblp;
529 struct tblentry **pp;
530 struct tblentry *cmdp;
533 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
535 while ((cmdp = *pp) != NULL) {
536 if ((cmdp->cmdtype == CMDNORMAL &&
537 cmdp->param.index >= firstchange)
538 || (cmdp->cmdtype == CMDBUILTIN &&
539 builtinloc >= firstchange)) {
552 * Delete all functions.
556 MKINIT void deletefuncs();
566 struct tblentry **tblp;
567 struct tblentry **pp;
568 struct tblentry *cmdp;
571 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
573 while ((cmdp = *pp) != NULL) {
574 if (cmdp->cmdtype == CMDFUNCTION) {
576 freefunc(cmdp->param.func);
589 * Locate a command in the command hash table. If "add" is nonzero,
590 * add the command to the table if it is not already present. The
591 * variable "lastcmdentry" is set to point to the address of the link
592 * pointing to the entry, so that delete_cmd_entry can delete the
596 struct tblentry **lastcmdentry;
599 STATIC struct tblentry *
600 cmdlookup(char *name, int add)
604 struct tblentry *cmdp;
605 struct tblentry **pp;
612 pp = &cmdtable[hashval % CMDTABLESIZE];
613 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
614 if (equal(cmdp->cmdname, name))
618 if (add && cmdp == NULL) {
620 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
623 cmdp->cmdtype = CMDUNKNOWN;
625 strcpy(cmdp->cmdname, name);
633 * Delete the command entry returned on the last lookup.
637 delete_cmd_entry(void)
639 struct tblentry *cmdp;
642 cmdp = *lastcmdentry;
643 *lastcmdentry = cmdp->next;
651 * Add a new command entry, replacing any existing command entry for
656 addcmdentry(char *name, struct cmdentry *entry)
658 struct tblentry *cmdp;
661 cmdp = cmdlookup(name, 1);
662 if (cmdp->cmdtype == CMDFUNCTION) {
663 freefunc(cmdp->param.func);
665 cmdp->cmdtype = entry->cmdtype;
666 cmdp->param = entry->u;
672 * Define a shell function.
676 defun(char *name, union node *func)
678 struct cmdentry entry;
681 entry.cmdtype = CMDFUNCTION;
682 entry.u.func = copyfunc(func);
683 addcmdentry(name, &entry);
689 * Delete a function if it exists.
693 unsetfunc(char *name)
695 struct tblentry *cmdp;
697 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
698 freefunc(cmdp->param.func);
706 * Locate and print what a word is...
710 typecmd(int argc, char **argv)
712 struct cmdentry entry;
713 struct tblentry *cmdp;
718 extern char *const parsekwd[];
720 for (i = 1; i < argc; i++) {
722 /* First look at the keywords */
723 for (pp = (char **)parsekwd; *pp; pp++)
724 if (**pp == *argv[i] && equal(*pp, argv[i]))
728 out1str(" is a shell keyword\n");
732 /* Then look at the aliases */
733 if ((ap = lookupalias(argv[i], 1)) != NULL) {
734 out1fmt(" is an alias for %s\n", ap->val);
738 /* Then check if it is a tracked alias */
739 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
740 entry.cmdtype = cmdp->cmdtype;
741 entry.u = cmdp->param;
744 /* Finally use brute force */
745 find_command(argv[i], &entry, 0, pathval());
748 switch (entry.cmdtype) {
750 if (strchr(argv[i], '/') == NULL) {
751 char *path = pathval(), *name;
752 int j = entry.u.index;
754 name = padvance(&path, argv[i]);
757 out1fmt(" is%s %s\n",
758 cmdp ? " a tracked alias for" : "", name);
760 if (access(argv[i], X_OK) == 0)
761 out1fmt(" is %s\n", argv[i]);
763 out1fmt(": %s\n", strerror(errno));
768 out1str(" is a shell function\n");
772 out1str(" is a shell builtin\n");
776 out1str(": not found\n");