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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20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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35 static char sccsid[] = "@(#)exec.c 8.4 (Berkeley) 6/8/95";
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
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);
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, char *path, int index)
117 if (strchr(argv[0], '/') != NULL) {
118 tryexec(argv[0], argv, envp);
122 while ((cmdname = padvance(&path, argv[0])) != NULL) {
123 if (--index < 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(char **path, char *name)
190 for (p = start ; *p && *p != ':' && *p != '%' ; p++);
191 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
192 while (stackblocksize() < len)
196 memcpy(q, start, p - start);
204 while (*p && *p != ':') p++;
215 /*** Command hashing code ***/
219 hashcmd(int argc __unused, char **argv __unused)
221 struct tblentry **pp;
222 struct tblentry *cmdp;
225 struct cmdentry entry;
229 while ((c = nextopt("rv")) != '\0') {
232 } else if (c == 'v') {
236 if (*argptr == NULL) {
237 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
238 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
239 if (cmdp->cmdtype == CMDNORMAL)
240 printentry(cmdp, verbose);
245 while ((name = *argptr) != NULL) {
246 if ((cmdp = cmdlookup(name, 0)) != NULL
247 && (cmdp->cmdtype == CMDNORMAL
248 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)))
250 find_command(name, &entry, 1, pathval());
252 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
253 cmdp = cmdlookup(name, 0);
255 printentry(cmdp, verbose);
257 outfmt(&errout, "%s: not found\n", name);
268 printentry(struct tblentry *cmdp, int verbose)
274 if (cmdp->cmdtype == CMDNORMAL) {
275 index = cmdp->param.index;
278 name = padvance(&path, cmdp->cmdname);
280 } while (--index >= 0);
282 } else if (cmdp->cmdtype == CMDBUILTIN) {
283 out1fmt("builtin %s", cmdp->cmdname);
284 } else if (cmdp->cmdtype == CMDFUNCTION) {
285 out1fmt("function %s", cmdp->cmdname);
288 name = commandtext(cmdp->param.func);
296 error("internal error: cmdtype %d", cmdp->cmdtype);
307 * Resolve a command name. If you change this routine, you may have to
308 * change the shellexec routine as well.
312 find_command(char *name, struct cmdentry *entry, int printerr, char *path)
314 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, &spec)) >= 0) {
337 cmdp = cmdlookup(name, 1);
338 cmdp->cmdtype = CMDBUILTIN;
339 cmdp->param.index = i;
340 cmdp->special = spec;
345 /* We have to search path. */
346 prev = -1; /* where to start */
347 if (cmdp) { /* doing a rehash */
348 if (cmdp->cmdtype == CMDBUILTIN)
351 prev = cmdp->param.index;
357 while ((fullname = padvance(&path, name)) != NULL) {
361 if (prefix("builtin", pathopt)) {
362 if ((i = find_builtin(name, &spec)) < 0)
365 cmdp = cmdlookup(name, 1);
366 cmdp->cmdtype = CMDBUILTIN;
367 cmdp->param.index = i;
368 cmdp->special = spec;
371 } else if (prefix("func", pathopt)) {
374 goto loop; /* ignore unimplemented options */
377 /* if rehash, don't redo absolute path names */
378 if (fullname[0] == '/' && index <= prev) {
381 TRACE(("searchexec \"%s\": no change\n", name));
384 if (stat(fullname, &statb) < 0) {
385 if (errno != ENOENT && errno != ENOTDIR)
389 e = EACCES; /* if we fail, this will be the error */
390 if (!S_ISREG(statb.st_mode))
392 if (pathopt) { /* this is a %func directory */
393 stalloc(strlen(fullname) + 1);
394 readcmdfile(fullname);
395 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
396 error("%s not defined in %s", name, fullname);
401 if (statb.st_uid == geteuid()) {
402 if ((statb.st_mode & 0100) == 0)
404 } else if (statb.st_gid == getegid()) {
405 if ((statb.st_mode & 010) == 0)
408 if ((statb.st_mode & 01) == 0)
412 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
414 cmdp = cmdlookup(name, 1);
415 cmdp->cmdtype = CMDNORMAL;
416 cmdp->param.index = index;
421 /* We failed. If there was an entry for this command, delete it */
425 if (e == ENOENT || e == ENOTDIR)
426 outfmt(out2, "%s: not found\n", name);
428 outfmt(out2, "%s: %s\n", name, strerror(e));
430 entry->cmdtype = CMDUNKNOWN;
435 entry->cmdtype = cmdp->cmdtype;
436 entry->u = cmdp->param;
437 entry->special = cmdp->special;
443 * Search the table of builtin commands.
447 find_builtin(char *name, int *special)
449 const struct builtincmd *bp;
451 for (bp = builtincmd ; bp->name ; bp++) {
452 if (*bp->name == *name && equal(bp->name, name)) {
453 *special = bp->special;
463 * Called when a cd is done. Marks all commands so the next time they
464 * are executed they will be rehashed.
470 struct tblentry **pp;
471 struct tblentry *cmdp;
473 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
474 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
475 if (cmdp->cmdtype == CMDNORMAL
476 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
485 * Called before PATH is changed. The argument is the new value of PATH;
486 * pathval() still returns the old value at this point. Called with
491 changepath(const char *newval)
493 const char *old, *new;
500 firstchange = 9999; /* assume no change */
506 if ((*old == '\0' && *new == ':')
507 || (*old == ':' && *new == '\0'))
509 old = new; /* ignore subsequent differences */
513 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
520 if (builtinloc < 0 && bltin >= 0)
521 builtinloc = bltin; /* zap builtins */
522 if (builtinloc >= 0 && bltin < 0)
524 clearcmdentry(firstchange);
530 * Clear out command entries. The argument specifies the first entry in
531 * PATH which has changed.
535 clearcmdentry(int firstchange)
537 struct tblentry **tblp;
538 struct tblentry **pp;
539 struct tblentry *cmdp;
542 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
544 while ((cmdp = *pp) != NULL) {
545 if ((cmdp->cmdtype == CMDNORMAL &&
546 cmdp->param.index >= firstchange)
547 || (cmdp->cmdtype == CMDBUILTIN &&
548 builtinloc >= firstchange)) {
561 * Delete all functions.
565 MKINIT void deletefuncs(void);
575 struct tblentry **tblp;
576 struct tblentry **pp;
577 struct tblentry *cmdp;
580 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
582 while ((cmdp = *pp) != NULL) {
583 if (cmdp->cmdtype == CMDFUNCTION) {
585 freefunc(cmdp->param.func);
598 * Locate a command in the command hash table. If "add" is nonzero,
599 * add the command to the table if it is not already present. The
600 * variable "lastcmdentry" is set to point to the address of the link
601 * pointing to the entry, so that delete_cmd_entry can delete the
605 STATIC struct tblentry **lastcmdentry;
608 STATIC struct tblentry *
609 cmdlookup(char *name, int add)
613 struct tblentry *cmdp;
614 struct tblentry **pp;
621 pp = &cmdtable[hashval % CMDTABLESIZE];
622 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
623 if (equal(cmdp->cmdname, name))
627 if (add && cmdp == NULL) {
629 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
632 cmdp->cmdtype = CMDUNKNOWN;
634 strcpy(cmdp->cmdname, name);
642 * Delete the command entry returned on the last lookup.
646 delete_cmd_entry(void)
648 struct tblentry *cmdp;
651 cmdp = *lastcmdentry;
652 *lastcmdentry = cmdp->next;
660 * Add a new command entry, replacing any existing command entry for
665 addcmdentry(char *name, struct cmdentry *entry)
667 struct tblentry *cmdp;
670 cmdp = cmdlookup(name, 1);
671 if (cmdp->cmdtype == CMDFUNCTION) {
672 freefunc(cmdp->param.func);
674 cmdp->cmdtype = entry->cmdtype;
675 cmdp->param = entry->u;
681 * Define a shell function.
685 defun(char *name, union node *func)
687 struct cmdentry entry;
690 entry.cmdtype = CMDFUNCTION;
691 entry.u.func = copyfunc(func);
692 addcmdentry(name, &entry);
698 * Delete a function if it exists.
702 unsetfunc(char *name)
704 struct tblentry *cmdp;
706 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
707 freefunc(cmdp->param.func);
715 * Shared code for the following builtin commands:
716 * type, command -v, command -V
720 typecmd_impl(int argc, char **argv, int cmd)
722 struct cmdentry entry;
723 struct tblentry *cmdp;
728 extern char *const parsekwd[];
730 for (i = 1; i < argc; i++) {
731 if (cmd != TYPECMD_SMALLV)
734 /* First look at the keywords */
735 for (pp = (char **)parsekwd; *pp; pp++)
736 if (**pp == *argv[i] && equal(*pp, argv[i]))
740 if (cmd == TYPECMD_SMALLV)
741 out1fmt("%s\n", argv[i]);
743 out1str(" is a shell keyword\n");
747 /* Then look at the aliases */
748 if ((ap = lookupalias(argv[i], 1)) != NULL) {
749 if (cmd == TYPECMD_SMALLV)
750 out1fmt("alias %s='%s'\n", argv[i], ap->val);
752 out1fmt(" is an alias for %s\n", ap->val);
756 /* Then check if it is a tracked alias */
757 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
758 entry.cmdtype = cmdp->cmdtype;
759 entry.u = cmdp->param;
762 /* Finally use brute force */
763 find_command(argv[i], &entry, 0, pathval());
766 switch (entry.cmdtype) {
768 if (strchr(argv[i], '/') == NULL) {
769 char *path = pathval(), *name;
770 int j = entry.u.index;
772 name = padvance(&path, argv[i]);
775 if (cmd == TYPECMD_SMALLV)
776 out1fmt("%s\n", name);
778 out1fmt(" is%s %s\n",
779 (cmdp && cmd == TYPECMD_TYPE) ?
780 " a tracked alias for" : "",
783 if (eaccess(argv[i], X_OK) == 0) {
784 if (cmd == TYPECMD_SMALLV)
785 out1fmt("%s\n", argv[i]);
787 out1fmt(" is %s\n", argv[i]);
789 if (cmd != TYPECMD_SMALLV)
798 if (cmd == TYPECMD_SMALLV)
799 out1fmt("%s\n", argv[i]);
801 out1str(" is a shell function\n");
805 if (cmd == TYPECMD_SMALLV)
806 out1fmt("%s\n", argv[i]);
808 out1str(" is a shell builtin\n");
812 if (cmd != TYPECMD_SMALLV)
813 out1str(": not found\n");
822 * Locate and print what a word is...
826 typecmd(int argc, char **argv)
828 return typecmd_impl(argc, argv, TYPECMD_TYPE);