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);
107 * Exec a program. Never returns. If you change this routine, you may
108 * have to change the find_command routine as well.
110 * The argv array may be changed and element argv[-1] should be writable.
114 shellexec(char **argv, char **envp, const char *path, int idx)
119 if (strchr(argv[0], '/') != NULL) {
120 tryexec(argv[0], argv, envp);
124 while ((cmdname = padvance(&path, argv[0])) != NULL) {
125 if (--idx < 0 && pathopt == NULL) {
126 tryexec(cmdname, argv, envp);
127 if (errno != ENOENT && errno != ENOTDIR)
136 /* Map to POSIX errors */
137 if (e == ENOENT || e == ENOTDIR) {
139 exerror(EXEXEC, "%s: not found", argv[0]);
142 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
148 tryexec(char *cmd, char **argv, char **envp)
154 execve(cmd, argv, envp);
158 in = open(cmd, O_RDONLY | O_NONBLOCK);
160 n = pread(in, buf, sizeof buf, 0);
162 if (n > 0 && memchr(buf, '\0', n) != NULL) {
168 *--argv = _PATH_BSHELL;
169 execve(_PATH_BSHELL, argv, envp);
175 * Do a path search. The variable path (passed by reference) should be
176 * set to the start of the path before the first call; padvance will update
177 * this value as it proceeds. Successive calls to padvance will return
178 * the possible path expansions in sequence. If an option (indicated by
179 * a percent sign) appears in the path entry then the global variable
180 * pathopt will be set to point to it; otherwise pathopt will be set to
187 padvance(const char **path, const char *name)
189 const char *p, *start;
196 for (p = start; *p && *p != ':' && *p != '%'; p++)
198 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
200 CHECKSTRSPACE(len, q);
202 memcpy(q, start, p - start);
210 while (*p && *p != ':') p++;
221 /*** Command hashing code ***/
225 hashcmd(int argc __unused, char **argv __unused)
227 struct tblentry **pp;
228 struct tblentry *cmdp;
231 struct cmdentry entry;
235 while ((c = nextopt("rv")) != '\0') {
238 } else if (c == 'v') {
242 if (*argptr == NULL) {
243 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
244 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
245 if (cmdp->cmdtype == CMDNORMAL)
246 printentry(cmdp, verbose);
251 while ((name = *argptr) != NULL) {
252 if ((cmdp = cmdlookup(name, 0)) != NULL
253 && cmdp->cmdtype == CMDNORMAL)
255 find_command(name, &entry, DO_ERR, pathval());
257 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
258 cmdp = cmdlookup(name, 0);
260 printentry(cmdp, verbose);
262 outfmt(out2, "%s: not found\n", name);
273 printentry(struct tblentry *cmdp, int verbose)
279 if (cmdp->cmdtype == CMDNORMAL) {
280 idx = cmdp->param.index;
283 name = padvance(&path, cmdp->cmdname);
285 } while (--idx >= 0);
287 } else if (cmdp->cmdtype == CMDBUILTIN) {
288 out1fmt("builtin %s", cmdp->cmdname);
289 } else if (cmdp->cmdtype == CMDFUNCTION) {
290 out1fmt("function %s", cmdp->cmdname);
293 name = commandtext(getfuncnode(cmdp->param.func));
301 error("internal error: cmdtype %d", cmdp->cmdtype);
312 * Resolve a command name. If you change this routine, you may have to
313 * change the shellexec routine as well.
317 find_command(const char *name, struct cmdentry *entry, int act,
320 struct tblentry *cmdp, loc_cmd;
329 /* If name contains a slash, don't use the hash table */
330 if (strchr(name, '/') != NULL) {
331 entry->cmdtype = CMDNORMAL;
336 /* If name is in the table, and not invalidated by cd, we're done */
337 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) {
338 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
344 /* Check for builtin next */
345 if ((i = find_builtin(name, &spec)) >= 0) {
347 cmdp = cmdlookup(name, 1);
348 if (cmdp->cmdtype == CMDFUNCTION)
350 cmdp->cmdtype = CMDBUILTIN;
351 cmdp->param.index = i;
352 cmdp->special = spec;
357 /* We have to search path. */
358 prev = -1; /* where to start */
359 if (cmdp) { /* doing a rehash */
360 if (cmdp->cmdtype == CMDBUILTIN)
363 prev = cmdp->param.index;
369 while ((fullname = padvance(&path, name)) != NULL) {
373 if (prefix("func", pathopt)) {
376 goto loop; /* ignore unimplemented options */
379 /* if rehash, don't redo absolute path names */
380 if (fullname[0] == '/' && idx <= prev) {
383 TRACE(("searchexec \"%s\": no change\n", name));
386 if (stat(fullname, &statb) < 0) {
387 if (errno != ENOENT && errno != ENOTDIR)
391 e = EACCES; /* if we fail, this will be the error */
392 if (!S_ISREG(statb.st_mode))
394 if (pathopt) { /* this is a %func directory */
395 stalloc(strlen(fullname) + 1);
396 readcmdfile(fullname);
397 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
398 error("%s not defined in %s", name, fullname);
403 if (statb.st_uid == geteuid()) {
404 if ((statb.st_mode & 0100) == 0)
406 } else if (statb.st_gid == getegid()) {
407 if ((statb.st_mode & 010) == 0)
410 if ((statb.st_mode & 01) == 0)
414 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
416 cmdp = cmdlookup(name, 1);
417 if (cmdp->cmdtype == CMDFUNCTION)
419 cmdp->cmdtype = CMDNORMAL;
420 cmdp->param.index = idx;
425 /* We failed. If there was an entry for this command, delete it */
426 if (cmdp && cmdp->cmdtype != CMDFUNCTION)
429 if (e == ENOENT || e == ENOTDIR)
430 outfmt(out2, "%s: not found\n", name);
432 outfmt(out2, "%s: %s\n", name, strerror(e));
434 entry->cmdtype = CMDUNKNOWN;
440 entry->cmdtype = cmdp->cmdtype;
441 entry->u = cmdp->param;
442 entry->special = cmdp->special;
448 * Search the table of builtin commands.
452 find_builtin(const char *name, int *special)
454 const struct builtincmd *bp;
456 for (bp = builtincmd ; bp->name ; bp++) {
457 if (*bp->name == *name && equal(bp->name, name)) {
458 *special = bp->special;
468 * Called when a cd is done. Marks all commands so the next time they
469 * are executed they will be rehashed.
475 struct tblentry **pp;
476 struct tblentry *cmdp;
478 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
479 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
480 if (cmdp->cmdtype == CMDNORMAL)
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)
502 * Clear out command entries. The argument specifies the first entry in
503 * PATH which has changed.
509 struct tblentry **tblp;
510 struct tblentry **pp;
511 struct tblentry *cmdp;
514 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
516 while ((cmdp = *pp) != NULL) {
517 if (cmdp->cmdtype == CMDNORMAL) {
530 * Locate a command in the command hash table. If "add" is nonzero,
531 * add the command to the table if it is not already present. The
532 * variable "lastcmdentry" is set to point to the address of the link
533 * pointing to the entry, so that delete_cmd_entry can delete the
537 static struct tblentry **lastcmdentry;
540 static struct tblentry *
541 cmdlookup(const char *name, int add)
545 struct tblentry *cmdp;
546 struct tblentry **pp;
553 pp = &cmdtable[hashval % CMDTABLESIZE];
554 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
555 if (equal(cmdp->cmdname, name))
559 if (add && cmdp == NULL) {
561 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
564 cmdp->cmdtype = CMDUNKNOWN;
566 strcpy(cmdp->cmdname, name);
574 * Delete the command entry returned on the last lookup.
578 delete_cmd_entry(void)
580 struct tblentry *cmdp;
583 cmdp = *lastcmdentry;
584 *lastcmdentry = cmdp->next;
592 * Add a new command entry, replacing any existing command entry for
597 addcmdentry(const char *name, struct cmdentry *entry)
599 struct tblentry *cmdp;
602 cmdp = cmdlookup(name, 1);
603 if (cmdp->cmdtype == CMDFUNCTION) {
604 unreffunc(cmdp->param.func);
606 cmdp->cmdtype = entry->cmdtype;
607 cmdp->param = entry->u;
613 * Define a shell function.
617 defun(const char *name, union node *func)
619 struct cmdentry entry;
622 entry.cmdtype = CMDFUNCTION;
623 entry.u.func = copyfunc(func);
624 addcmdentry(name, &entry);
630 * Delete a function if it exists.
634 unsetfunc(const char *name)
636 struct tblentry *cmdp;
638 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
639 unreffunc(cmdp->param.func);
647 * Shared code for the following builtin commands:
648 * type, command -v, command -V
652 typecmd_impl(int argc, char **argv, int cmd, const char *path)
654 struct cmdentry entry;
655 struct tblentry *cmdp;
656 const char *const *pp;
661 if (path != pathval())
664 for (i = 1; i < argc; i++) {
665 /* First look at the keywords */
666 for (pp = parsekwd; *pp; pp++)
667 if (**pp == *argv[i] && equal(*pp, argv[i]))
671 if (cmd == TYPECMD_SMALLV)
672 out1fmt("%s\n", argv[i]);
674 out1fmt("%s is a shell keyword\n", argv[i]);
678 /* Then look at the aliases */
679 if ((ap = lookupalias(argv[i], 1)) != NULL) {
680 if (cmd == TYPECMD_SMALLV)
681 out1fmt("alias %s='%s'\n", argv[i], ap->val);
683 out1fmt("%s is an alias for %s\n", argv[i],
688 /* Then check if it is a tracked alias */
689 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
690 entry.cmdtype = cmdp->cmdtype;
691 entry.u = cmdp->param;
692 entry.special = cmdp->special;
695 /* Finally use brute force */
696 find_command(argv[i], &entry, 0, path);
699 switch (entry.cmdtype) {
701 if (strchr(argv[i], '/') == NULL) {
702 const char *path2 = path;
704 int j = entry.u.index;
706 name = padvance(&path2, argv[i]);
709 if (cmd == TYPECMD_SMALLV)
710 out1fmt("%s\n", name);
712 out1fmt("%s is%s %s\n", argv[i],
713 (cmdp && cmd == TYPECMD_TYPE) ?
714 " a tracked alias for" : "",
717 if (eaccess(argv[i], X_OK) == 0) {
718 if (cmd == TYPECMD_SMALLV)
719 out1fmt("%s\n", argv[i]);
721 out1fmt("%s is %s\n", argv[i],
724 if (cmd != TYPECMD_SMALLV)
725 outfmt(out2, "%s: %s\n",
726 argv[i], strerror(errno));
733 if (cmd == TYPECMD_SMALLV)
734 out1fmt("%s\n", argv[i]);
736 out1fmt("%s is a shell function\n", argv[i]);
740 if (cmd == TYPECMD_SMALLV)
741 out1fmt("%s\n", argv[i]);
742 else if (entry.special)
743 out1fmt("%s is a special shell builtin\n",
746 out1fmt("%s is a shell builtin\n", argv[i]);
750 if (cmd != TYPECMD_SMALLV)
751 outfmt(out2, "%s: not found\n", argv[i]);
757 if (path != pathval())
764 * Locate and print what a word is...
768 typecmd(int argc, char **argv)
770 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));