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.
79 #define CMDTABLESIZE 31 /* should be prime */
84 struct tblentry *next; /* next entry in hash chain */
85 union param param; /* definition of builtin function */
86 int special; /* flag for special builtin commands */
87 signed char cmdtype; /* index identifying command */
88 char cmdname[]; /* name of command */
92 static struct tblentry *cmdtable[CMDTABLESIZE];
93 static int cmdtable_cd = 0; /* cmdtable contains cd-dependent entries */
96 static void tryexec(char *, char **, char **);
97 static void printentry(struct tblentry *, int);
98 static struct tblentry *cmdlookup(const char *, int);
99 static void delete_cmd_entry(void);
100 static void addcmdentry(const char *, struct cmdentry *);
105 * Exec a program. Never returns. If you change this routine, you may
106 * have to change the find_command routine as well.
108 * The argv array may be changed and element argv[-1] should be writable.
112 shellexec(char **argv, char **envp, const char *path, int idx)
118 if (strchr(argv[0], '/') != NULL) {
119 tryexec(argv[0], argv, envp);
123 while ((cmdname = padvance(&path, &opt, argv[0])) != NULL) {
124 if (--idx < 0 && opt == NULL) {
125 tryexec(cmdname, argv, envp);
126 if (errno != ENOENT && errno != ENOTDIR)
135 /* Map to POSIX errors */
136 if (e == ENOENT || e == ENOTDIR)
137 errorwithstatus(127, "%s: not found", argv[0]);
139 errorwithstatus(126, "%s: %s", argv[0], strerror(e));
144 tryexec(char *cmd, char **argv, char **envp)
150 execve(cmd, argv, envp);
154 in = open(cmd, O_RDONLY | O_NONBLOCK);
156 n = pread(in, buf, sizeof buf, 0);
158 if (n > 0 && memchr(buf, '\0', n) != NULL) {
164 *--argv = __DECONST(char *, _PATH_BSHELL);
165 execve(_PATH_BSHELL, argv, envp);
171 * Do a path search. The variable path (passed by reference) should be
172 * set to the start of the path before the first call; padvance will update
173 * this value as it proceeds. Successive calls to padvance will return
174 * the possible path expansions in sequence. If popt is not NULL, options
175 * are processed: if an option (indicated by a percent sign) appears in
176 * the path entry then *popt will be set to point to it; else *popt will be
177 * set to NULL. If popt is NULL, percent signs are not special.
181 padvance(const char **path, const char **popt, const char *name)
183 const char *p, *start;
191 for (p = start; *p && *p != ':' && *p != '%'; p++)
194 for (p = start; *p && *p != ':'; p++)
196 namelen = strlen(name);
197 len = p - start + namelen + 2; /* "2" is for '/' and '\0' */
199 CHECKSTRSPACE(len, q);
201 memcpy(q, start, p - start);
205 memcpy(q, name, namelen + 1);
209 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)
281 const char *path, *opt;
284 if (cmdp->cmdtype == CMDNORMAL) {
285 idx = cmdp->param.index;
288 name = padvance(&path, &opt, 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);
315 * Resolve a command name. If you change this routine, you may have to
316 * change the shellexec routine as well.
320 find_command(const char *name, struct cmdentry *entry, int act,
323 struct tblentry *cmdp, loc_cmd;
333 /* If name contains a slash, don't use the hash table */
334 if (strchr(name, '/') != NULL) {
335 entry->cmdtype = CMDNORMAL;
343 /* If name is in the table, we're done */
344 if ((cmdp = cmdlookup(name, 0)) != NULL) {
345 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
351 /* Check for builtin next */
352 if ((i = find_builtin(name, &spec)) >= 0) {
354 cmdp = cmdlookup(name, 1);
355 if (cmdp->cmdtype == CMDFUNCTION)
357 cmdp->cmdtype = CMDBUILTIN;
358 cmdp->param.index = i;
359 cmdp->special = spec;
364 /* We have to search path. */
368 for (;(fullname = padvance(&path, &opt, name)) != NULL;
369 stunalloc(fullname)) {
372 if (strncmp(opt, "func", 4) == 0) {
375 continue; /* ignore unimplemented options */
378 if (fullname[0] != '/')
380 if (stat(fullname, &statb) < 0) {
381 if (errno != ENOENT && errno != ENOTDIR)
385 e = EACCES; /* if we fail, this will be the error */
386 if (!S_ISREG(statb.st_mode))
388 if (opt) { /* this is a %func directory */
389 readcmdfile(fullname);
390 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
391 error("%s not defined in %s", name, fullname);
396 if (statb.st_uid == geteuid()) {
397 if ((statb.st_mode & 0100) == 0)
399 } else if (statb.st_gid == getegid()) {
400 if ((statb.st_mode & 010) == 0)
403 if ((statb.st_mode & 01) == 0)
407 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
410 cmdp = cmdlookup(name, 1);
411 if (cmdp->cmdtype == CMDFUNCTION)
413 cmdp->cmdtype = CMDNORMAL;
414 cmdp->param.index = idx;
421 if (e == ENOENT || e == ENOTDIR)
422 outfmt(out2, "%s: not found\n", name);
424 outfmt(out2, "%s: %s\n", name, strerror(e));
426 entry->cmdtype = CMDUNKNOWN;
434 entry->cmdtype = cmdp->cmdtype;
435 entry->u = cmdp->param;
436 entry->special = cmdp->special;
442 * Search the table of builtin commands.
446 find_builtin(const char *name, int *special)
448 const unsigned char *bp;
452 for (bp = builtincmd ; *bp ; bp += 2 + bp[0]) {
453 if (bp[0] == len && memcmp(bp + 2, name, len) == 0) {
454 *special = (bp[1] & BUILTIN_SPECIAL) != 0;
455 return bp[1] & ~BUILTIN_SPECIAL;
464 * Called when a cd is done. If any entry in cmdtable depends on the current
465 * directory, simply clear cmdtable completely.
478 * Called before PATH is changed. The argument is the new value of PATH;
479 * pathval() still returns the old value at this point. Called with
484 changepath(const char *newval __unused)
491 * Clear out cached utility locations.
497 struct tblentry **tblp;
498 struct tblentry **pp;
499 struct tblentry *cmdp;
502 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
504 while ((cmdp = *pp) != NULL) {
505 if (cmdp->cmdtype == CMDNORMAL) {
519 * Locate a command in the command hash table. If "add" is nonzero,
520 * add the command to the table if it is not already present. The
521 * variable "lastcmdentry" is set to point to the address of the link
522 * pointing to the entry, so that delete_cmd_entry can delete the
526 static struct tblentry **lastcmdentry;
529 static struct tblentry *
530 cmdlookup(const char *name, int add)
532 unsigned int hashval;
534 struct tblentry *cmdp;
535 struct tblentry **pp;
539 hashval = (unsigned char)*p << 4;
542 pp = &cmdtable[hashval % CMDTABLESIZE];
543 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
544 if (equal(cmdp->cmdname, name))
548 if (add && cmdp == NULL) {
551 cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1);
553 cmdp->cmdtype = CMDUNKNOWN;
554 memcpy(cmdp->cmdname, name, len + 1);
562 * Delete the command entry returned on the last lookup.
566 delete_cmd_entry(void)
568 struct tblentry *cmdp;
571 cmdp = *lastcmdentry;
572 *lastcmdentry = cmdp->next;
580 * Add a new command entry, replacing any existing command entry for
585 addcmdentry(const char *name, struct cmdentry *entry)
587 struct tblentry *cmdp;
590 cmdp = cmdlookup(name, 1);
591 if (cmdp->cmdtype == CMDFUNCTION) {
592 unreffunc(cmdp->param.func);
594 cmdp->cmdtype = entry->cmdtype;
595 cmdp->param = entry->u;
596 cmdp->special = entry->special;
602 * Define a shell function.
606 defun(const char *name, union node *func)
608 struct cmdentry entry;
611 entry.cmdtype = CMDFUNCTION;
612 entry.u.func = copyfunc(func);
614 addcmdentry(name, &entry);
620 * Delete a function if it exists.
621 * Called with interrupts off.
625 unsetfunc(const char *name)
627 struct tblentry *cmdp;
629 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
630 unreffunc(cmdp->param.func);
639 * Check if a function by a certain name exists.
642 isfunc(const char *name)
644 struct tblentry *cmdp;
645 cmdp = cmdlookup(name, 0);
646 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
651 * Shared code for the following builtin commands:
652 * type, command -v, command -V
656 typecmd_impl(int argc, char **argv, int cmd, const char *path)
658 struct cmdentry entry;
659 struct tblentry *cmdp;
660 const char *const *pp;
665 if (path != pathval())
668 for (i = 1; i < argc; i++) {
669 /* First look at the keywords */
670 for (pp = parsekwd; *pp; pp++)
671 if (**pp == *argv[i] && equal(*pp, argv[i]))
675 if (cmd == TYPECMD_SMALLV)
676 out1fmt("%s\n", argv[i]);
678 out1fmt("%s is a shell keyword\n", argv[i]);
682 /* Then look at the aliases */
683 if ((ap = lookupalias(argv[i], 1)) != NULL) {
684 if (cmd == TYPECMD_SMALLV) {
685 out1fmt("alias %s=", argv[i]);
687 outcslow('\n', out1);
689 out1fmt("%s is an alias for %s\n", argv[i],
694 /* Then check if it is a tracked alias */
695 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
696 entry.cmdtype = cmdp->cmdtype;
697 entry.u = cmdp->param;
698 entry.special = cmdp->special;
701 /* Finally use brute force */
702 find_command(argv[i], &entry, 0, path);
705 switch (entry.cmdtype) {
707 if (strchr(argv[i], '/') == NULL) {
708 const char *path2 = path;
711 int j = entry.u.index;
713 name = padvance(&path2, &opt2, argv[i]);
716 if (cmd == TYPECMD_SMALLV)
717 out1fmt("%s\n", name);
719 out1fmt("%s is%s %s\n", argv[i],
720 (cmdp && cmd == TYPECMD_TYPE) ?
721 " a tracked alias for" : "",
724 if (eaccess(argv[i], X_OK) == 0) {
725 if (cmd == TYPECMD_SMALLV)
726 out1fmt("%s\n", argv[i]);
728 out1fmt("%s is %s\n", argv[i],
731 if (cmd != TYPECMD_SMALLV)
732 outfmt(out2, "%s: %s\n",
733 argv[i], strerror(errno));
740 if (cmd == TYPECMD_SMALLV)
741 out1fmt("%s\n", argv[i]);
743 out1fmt("%s is a shell function\n", argv[i]);
747 if (cmd == TYPECMD_SMALLV)
748 out1fmt("%s\n", argv[i]);
749 else if (entry.special)
750 out1fmt("%s is a special shell builtin\n",
753 out1fmt("%s is a shell builtin\n", argv[i]);
757 if (cmd != TYPECMD_SMALLV)
758 outfmt(out2, "%s: not found\n", argv[i]);
764 if (path != pathval())
771 * Locate and print what a word is...
775 typecmd(int argc, char **argv)
777 if (argc > 2 && strcmp(argv[1], "--") == 0)
779 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));