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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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>
50 * When commands are first encountered, they are entered in a hash table.
51 * This ensures that a full path search will not have to be done for them
54 * We should investigate converting to a linear search, even though that
55 * would make the command name "hash" a misnomer.
80 #define CMDTABLESIZE 31 /* should be prime */
81 #define ARB 1 /* actual size determined at run time */
86 struct tblentry *next; /* next entry in hash chain */
87 union param param; /* definition of builtin function */
88 int special; /* flag for special builtin commands */
89 short cmdtype; /* index identifying command */
90 char rehash; /* if set, cd done since entry created */
91 char cmdname[ARB]; /* name of command */
95 static struct tblentry *cmdtable[CMDTABLESIZE];
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(const char *, int);
102 static void delete_cmd_entry(void);
103 static void addcmdentry(const char *, struct cmdentry *);
108 * Exec a program. Never returns. If you change this routine, you may
109 * have to change the find_command routine as well.
111 * The argv array may be changed and element argv[-1] should be writable.
115 shellexec(char **argv, char **envp, const char *path, int idx)
120 if (strchr(argv[0], '/') != NULL) {
121 tryexec(argv[0], argv, envp);
125 while ((cmdname = padvance(&path, argv[0])) != NULL) {
126 if (--idx < 0 && pathopt == NULL) {
127 tryexec(cmdname, argv, envp);
128 if (errno != ENOENT && errno != ENOTDIR)
137 /* Map to POSIX errors */
138 if (e == ENOENT || e == ENOTDIR) {
140 exerror(EXEXEC, "%s: not found", argv[0]);
143 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
149 tryexec(char *cmd, char **argv, char **envp)
155 execve(cmd, argv, envp);
159 in = open(cmd, O_RDONLY | O_NONBLOCK);
161 n = pread(in, buf, sizeof buf, 0);
163 if (n > 0 && memchr(buf, '\0', n) != NULL) {
169 *--argv = _PATH_BSHELL;
170 execve(_PATH_BSHELL, argv, envp);
176 * Do a path search. The variable path (passed by reference) should be
177 * set to the start of the path before the first call; padvance will update
178 * this value as it proceeds. Successive calls to padvance will return
179 * the possible path expansions in sequence. If an option (indicated by
180 * a percent sign) appears in the path entry then the global variable
181 * pathopt will be set to point to it; otherwise pathopt will be set to
188 padvance(const char **path, const char *name)
190 const char *p, *start;
197 for (p = start; *p && *p != ':' && *p != '%'; p++)
199 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
201 CHECKSTRSPACE(len, q);
203 memcpy(q, start, p - start);
211 while (*p && *p != ':') p++;
222 /*** Command hashing code ***/
226 hashcmd(int argc __unused, char **argv __unused)
228 struct tblentry **pp;
229 struct tblentry *cmdp;
232 struct cmdentry entry;
238 while ((c = nextopt("rv")) != '\0') {
241 } else if (c == 'v') {
245 if (*argptr == NULL) {
246 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
247 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
248 if (cmdp->cmdtype == CMDNORMAL)
249 printentry(cmdp, verbose);
254 while ((name = *argptr) != NULL) {
255 if ((cmdp = cmdlookup(name, 0)) != NULL
256 && cmdp->cmdtype == CMDNORMAL)
258 find_command(name, &entry, DO_ERR, pathval());
259 if (entry.cmdtype == CMDUNKNOWN)
262 cmdp = cmdlookup(name, 0);
264 printentry(cmdp, verbose);
266 outfmt(out2, "%s: not found\n", name);
278 printentry(struct tblentry *cmdp, int verbose)
284 if (cmdp->cmdtype == CMDNORMAL) {
285 idx = cmdp->param.index;
288 name = padvance(&path, cmdp->cmdname);
290 } while (--idx >= 0);
292 } else if (cmdp->cmdtype == CMDBUILTIN) {
293 out1fmt("builtin %s", cmdp->cmdname);
294 } else if (cmdp->cmdtype == CMDFUNCTION) {
295 out1fmt("function %s", cmdp->cmdname);
298 name = commandtext(getfuncnode(cmdp->param.func));
306 error("internal error: cmdtype %d", cmdp->cmdtype);
317 * Resolve a command name. If you change this routine, you may have to
318 * change the shellexec routine as well.
322 find_command(const char *name, struct cmdentry *entry, int act,
325 struct tblentry *cmdp, loc_cmd;
334 /* If name contains a slash, don't use the hash table */
335 if (strchr(name, '/') != NULL) {
336 entry->cmdtype = CMDNORMAL;
341 /* If name is in the table, and not invalidated by cd, we're done */
342 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) {
343 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
349 /* Check for builtin next */
350 if ((i = find_builtin(name, &spec)) >= 0) {
352 cmdp = cmdlookup(name, 1);
353 if (cmdp->cmdtype == CMDFUNCTION)
355 cmdp->cmdtype = CMDBUILTIN;
356 cmdp->param.index = i;
357 cmdp->special = spec;
362 /* We have to search path. */
363 prev = -1; /* where to start */
364 if (cmdp) { /* doing a rehash */
365 if (cmdp->cmdtype == CMDBUILTIN)
368 prev = cmdp->param.index;
374 while ((fullname = padvance(&path, name)) != NULL) {
378 if (prefix("func", pathopt)) {
381 goto loop; /* ignore unimplemented options */
384 /* if rehash, don't redo absolute path names */
385 if (fullname[0] == '/' && idx <= prev) {
388 TRACE(("searchexec \"%s\": no change\n", name));
391 if (stat(fullname, &statb) < 0) {
392 if (errno != ENOENT && errno != ENOTDIR)
396 e = EACCES; /* if we fail, this will be the error */
397 if (!S_ISREG(statb.st_mode))
399 if (pathopt) { /* this is a %func directory */
400 stalloc(strlen(fullname) + 1);
401 readcmdfile(fullname);
402 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
403 error("%s not defined in %s", name, fullname);
408 if (statb.st_uid == geteuid()) {
409 if ((statb.st_mode & 0100) == 0)
411 } else if (statb.st_gid == getegid()) {
412 if ((statb.st_mode & 010) == 0)
415 if ((statb.st_mode & 01) == 0)
419 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
421 cmdp = cmdlookup(name, 1);
422 if (cmdp->cmdtype == CMDFUNCTION)
424 cmdp->cmdtype = CMDNORMAL;
425 cmdp->param.index = idx;
430 /* We failed. If there was an entry for this command, delete it */
431 if (cmdp && cmdp->cmdtype != CMDFUNCTION)
434 if (e == ENOENT || e == ENOTDIR)
435 outfmt(out2, "%s: not found\n", name);
437 outfmt(out2, "%s: %s\n", name, strerror(e));
439 entry->cmdtype = CMDUNKNOWN;
445 entry->cmdtype = cmdp->cmdtype;
446 entry->u = cmdp->param;
447 entry->special = cmdp->special;
453 * Search the table of builtin commands.
457 find_builtin(const char *name, int *special)
459 const struct builtincmd *bp;
461 for (bp = builtincmd ; bp->name ; bp++) {
462 if (*bp->name == *name && equal(bp->name, name)) {
463 *special = bp->special;
473 * Called when a cd is done. Marks all commands so the next time they
474 * are executed they will be rehashed.
480 struct tblentry **pp;
481 struct tblentry *cmdp;
483 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
484 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
485 if (cmdp->cmdtype == CMDNORMAL)
494 * Called before PATH is changed. The argument is the new value of PATH;
495 * pathval() still returns the old value at this point. Called with
500 changepath(const char *newval __unused)
507 * Clear out command entries. The argument specifies the first entry in
508 * PATH which has changed.
514 struct tblentry **tblp;
515 struct tblentry **pp;
516 struct tblentry *cmdp;
519 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
521 while ((cmdp = *pp) != NULL) {
522 if (cmdp->cmdtype == CMDNORMAL) {
535 * Locate a command in the command hash table. If "add" is nonzero,
536 * add the command to the table if it is not already present. The
537 * variable "lastcmdentry" is set to point to the address of the link
538 * pointing to the entry, so that delete_cmd_entry can delete the
542 static struct tblentry **lastcmdentry;
545 static struct tblentry *
546 cmdlookup(const char *name, int add)
550 struct tblentry *cmdp;
551 struct tblentry **pp;
558 pp = &cmdtable[hashval % CMDTABLESIZE];
559 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
560 if (equal(cmdp->cmdname, name))
564 if (add && cmdp == NULL) {
566 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
569 cmdp->cmdtype = CMDUNKNOWN;
571 strcpy(cmdp->cmdname, name);
579 * Delete the command entry returned on the last lookup.
583 delete_cmd_entry(void)
585 struct tblentry *cmdp;
588 cmdp = *lastcmdentry;
589 *lastcmdentry = cmdp->next;
597 * Add a new command entry, replacing any existing command entry for
602 addcmdentry(const char *name, struct cmdentry *entry)
604 struct tblentry *cmdp;
607 cmdp = cmdlookup(name, 1);
608 if (cmdp->cmdtype == CMDFUNCTION) {
609 unreffunc(cmdp->param.func);
611 cmdp->cmdtype = entry->cmdtype;
612 cmdp->param = entry->u;
618 * Define a shell function.
622 defun(const char *name, union node *func)
624 struct cmdentry entry;
627 entry.cmdtype = CMDFUNCTION;
628 entry.u.func = copyfunc(func);
629 addcmdentry(name, &entry);
635 * Delete a function if it exists.
639 unsetfunc(const char *name)
641 struct tblentry *cmdp;
643 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
644 unreffunc(cmdp->param.func);
653 * Check if a function by a certain name exists.
656 isfunc(const char *name)
658 struct tblentry *cmdp;
659 cmdp = cmdlookup(name, 0);
660 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
665 * Shared code for the following builtin commands:
666 * type, command -v, command -V
670 typecmd_impl(int argc, char **argv, int cmd, const char *path)
672 struct cmdentry entry;
673 struct tblentry *cmdp;
674 const char *const *pp;
679 if (path != pathval())
682 for (i = 1; i < argc; i++) {
683 /* First look at the keywords */
684 for (pp = parsekwd; *pp; pp++)
685 if (**pp == *argv[i] && equal(*pp, argv[i]))
689 if (cmd == TYPECMD_SMALLV)
690 out1fmt("%s\n", argv[i]);
692 out1fmt("%s is a shell keyword\n", argv[i]);
696 /* Then look at the aliases */
697 if ((ap = lookupalias(argv[i], 1)) != NULL) {
698 if (cmd == TYPECMD_SMALLV)
699 out1fmt("alias %s='%s'\n", argv[i], ap->val);
701 out1fmt("%s is an alias for %s\n", argv[i],
706 /* Then check if it is a tracked alias */
707 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
708 entry.cmdtype = cmdp->cmdtype;
709 entry.u = cmdp->param;
710 entry.special = cmdp->special;
713 /* Finally use brute force */
714 find_command(argv[i], &entry, 0, path);
717 switch (entry.cmdtype) {
719 if (strchr(argv[i], '/') == NULL) {
720 const char *path2 = path;
722 int j = entry.u.index;
724 name = padvance(&path2, argv[i]);
727 if (cmd == TYPECMD_SMALLV)
728 out1fmt("%s\n", name);
730 out1fmt("%s is%s %s\n", argv[i],
731 (cmdp && cmd == TYPECMD_TYPE) ?
732 " a tracked alias for" : "",
735 if (eaccess(argv[i], X_OK) == 0) {
736 if (cmd == TYPECMD_SMALLV)
737 out1fmt("%s\n", argv[i]);
739 out1fmt("%s is %s\n", argv[i],
742 if (cmd != TYPECMD_SMALLV)
743 outfmt(out2, "%s: %s\n",
744 argv[i], strerror(errno));
751 if (cmd == TYPECMD_SMALLV)
752 out1fmt("%s\n", argv[i]);
754 out1fmt("%s is a shell function\n", argv[i]);
758 if (cmd == TYPECMD_SMALLV)
759 out1fmt("%s\n", argv[i]);
760 else if (entry.special)
761 out1fmt("%s is a special shell builtin\n",
764 out1fmt("%s is a shell builtin\n", argv[i]);
768 if (cmd != TYPECMD_SMALLV)
769 outfmt(out2, "%s: not found\n", argv[i]);
775 if (path != pathval())
782 * Locate and print what a word is...
786 typecmd(int argc, char **argv)
788 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));