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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36 * @(#)exec.c 8.4 (Berkeley) 6/8/95
37 * $FreeBSD: src/bin/sh/exec.c,v 1.53 2012/01/01 22:17:12 jilles Exp $
40 #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 int exerrno = 0; /* Last exec error */
98 static void tryexec(char *, char **, char **);
99 static void printentry(struct tblentry *, int);
100 static struct tblentry *cmdlookup(const char *, int);
101 static void delete_cmd_entry(void);
102 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)
117 if (strchr(argv[0], '/') != NULL) {
118 tryexec(argv[0], argv, envp);
122 while ((cmdname = padvance(&path, argv[0])) != NULL) {
123 if (--idx < 0 && pathopt == NULL) {
124 tryexec(cmdname, argv, envp);
125 if (errno != ENOENT && errno != ENOTDIR)
134 /* Map to POSIX errors */
135 if (e == ENOENT || e == ENOTDIR) {
137 exerror(EXEXEC, "%s: not found", argv[0]);
140 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
146 tryexec(char *cmd, char **argv, char **envp)
152 execve(cmd, argv, envp);
156 in = open(cmd, O_RDONLY | O_NONBLOCK);
158 n = pread(in, buf, sizeof buf, 0);
160 if (n > 0 && memchr(buf, '\0', n) != NULL) {
166 *--argv = __DECONST(char *, _PATH_BSHELL);
167 execve(_PATH_BSHELL, argv, envp);
173 * Do a path search. The variable path (passed by reference) should be
174 * set to the start of the path before the first call; padvance will update
175 * this value as it proceeds. Successive calls to padvance will return
176 * the possible path expansions in sequence. If an option (indicated by
177 * a percent sign) appears in the path entry then the global variable
178 * pathopt will be set to point to it; otherwise pathopt will be set to
185 padvance(const char **path, const char *name)
187 const char *p, *start;
194 for (p = start; *p && *p != ':' && *p != '%'; p++)
196 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
198 CHECKSTRSPACE(len, q);
200 memcpy(q, start, p - start);
208 while (*p && *p != ':') p++;
219 /*** Command hashing code ***/
223 hashcmd(int argc __unused, char **argv __unused)
225 struct tblentry **pp;
226 struct tblentry *cmdp;
229 struct cmdentry entry;
233 while ((c = nextopt("rv")) != '\0') {
236 } else if (c == 'v') {
240 if (*argptr == NULL) {
241 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
242 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
243 if (cmdp->cmdtype == CMDNORMAL)
244 printentry(cmdp, verbose);
249 while ((name = *argptr) != NULL) {
250 if ((cmdp = cmdlookup(name, 0)) != NULL
251 && cmdp->cmdtype == CMDNORMAL)
253 find_command(name, &entry, DO_ERR, pathval());
255 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
256 cmdp = cmdlookup(name, 0);
258 printentry(cmdp, verbose);
260 outfmt(out2, "%s: not found\n", name);
271 printentry(struct tblentry *cmdp, int verbose)
277 if (cmdp->cmdtype == CMDNORMAL) {
278 idx = cmdp->param.index;
281 name = padvance(&path, cmdp->cmdname);
283 } while (--idx >= 0);
285 } else if (cmdp->cmdtype == CMDBUILTIN) {
286 out1fmt("builtin %s", cmdp->cmdname);
287 } else if (cmdp->cmdtype == CMDFUNCTION) {
288 out1fmt("function %s", cmdp->cmdname);
291 name = commandtext(getfuncnode(cmdp->param.func));
299 error("internal error: cmdtype %d", cmdp->cmdtype);
310 * Resolve a command name. If you change this routine, you may have to
311 * change the shellexec routine as well.
315 find_command(const char *name, struct cmdentry *entry, int act,
318 struct tblentry *cmdp, loc_cmd;
327 /* If name contains a slash, don't use the hash table */
328 if (strchr(name, '/') != NULL) {
329 entry->cmdtype = CMDNORMAL;
334 /* If name is in the table, and not invalidated by cd, we're done */
335 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) {
336 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
342 /* Check for builtin next */
343 if ((i = find_builtin(name, &spec)) >= 0) {
345 cmdp = cmdlookup(name, 1);
346 if (cmdp->cmdtype == CMDFUNCTION)
348 cmdp->cmdtype = CMDBUILTIN;
349 cmdp->param.index = i;
350 cmdp->special = spec;
355 /* We have to search path. */
356 prev = -1; /* where to start */
357 if (cmdp) { /* doing a rehash */
358 if (cmdp->cmdtype == CMDBUILTIN)
361 prev = cmdp->param.index;
367 while ((fullname = padvance(&path, name)) != NULL) {
371 if (prefix("func", pathopt)) {
374 goto loop; /* ignore unimplemented options */
377 /* if rehash, don't redo absolute path names */
378 if (fullname[0] == '/' && idx <= 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 if (cmdp->cmdtype == CMDFUNCTION)
417 cmdp->cmdtype = CMDNORMAL;
418 cmdp->param.index = idx;
423 /* We failed. If there was an entry for this command, delete it */
424 if (cmdp && cmdp->cmdtype != CMDFUNCTION)
427 if (e == ENOENT || e == ENOTDIR)
428 outfmt(out2, "%s: not found\n", name);
430 outfmt(out2, "%s: %s\n", name, strerror(e));
432 entry->cmdtype = CMDUNKNOWN;
439 entry->cmdtype = cmdp->cmdtype;
440 entry->u = cmdp->param;
441 entry->special = cmdp->special;
443 entry->cmdtype = CMDUNKNOWN;
449 * Search the table of builtin commands.
453 find_builtin(const char *name, int *special)
455 const struct builtincmd *bp;
457 for (bp = builtincmd ; bp->name ; bp++) {
458 if (*bp->name == *name && equal(bp->name, name)) {
459 *special = bp->special;
469 * Called when a cd is done. Marks all commands so the next time they
470 * are executed they will be rehashed.
476 struct tblentry **pp;
477 struct tblentry *cmdp;
479 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
480 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
481 if (cmdp->cmdtype == CMDNORMAL)
490 * Called before PATH is changed. The argument is the new value of PATH;
491 * pathval() still returns the old value at this point. Called with
496 changepath(const char *newval __unused)
503 * Clear out command entries. The argument specifies the first entry in
504 * PATH which has changed.
510 struct tblentry **tblp;
511 struct tblentry **pp;
512 struct tblentry *cmdp;
515 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
517 while ((cmdp = *pp) != NULL) {
518 if (cmdp->cmdtype == CMDNORMAL) {
531 * Locate a command in the command hash table. If "add" is nonzero,
532 * add the command to the table if it is not already present. The
533 * variable "lastcmdentry" is set to point to the address of the link
534 * pointing to the entry, so that delete_cmd_entry can delete the
538 static struct tblentry **lastcmdentry;
541 static struct tblentry *
542 cmdlookup(const char *name, int add)
546 struct tblentry *cmdp;
547 struct tblentry **pp;
554 pp = &cmdtable[hashval % CMDTABLESIZE];
555 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
556 if (equal(cmdp->cmdname, name))
560 if (add && cmdp == NULL) {
562 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
565 cmdp->cmdtype = CMDUNKNOWN;
567 strcpy(cmdp->cmdname, name);
575 * Delete the command entry returned on the last lookup.
579 delete_cmd_entry(void)
581 struct tblentry *cmdp;
584 cmdp = *lastcmdentry;
585 *lastcmdentry = cmdp->next;
593 * Add a new command entry, replacing any existing command entry for
598 addcmdentry(const char *name, struct cmdentry *entry)
600 struct tblentry *cmdp;
603 cmdp = cmdlookup(name, 1);
604 if (cmdp->cmdtype == CMDFUNCTION) {
605 unreffunc(cmdp->param.func);
607 cmdp->cmdtype = entry->cmdtype;
608 cmdp->param = entry->u;
614 * Define a shell function.
618 defun(const char *name, union node *func)
620 struct cmdentry entry;
623 entry.cmdtype = CMDFUNCTION;
624 entry.u.func = copyfunc(func);
625 addcmdentry(name, &entry);
631 * Delete a function if it exists.
635 unsetfunc(const char *name)
637 struct tblentry *cmdp;
639 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
640 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 (access(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));