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>
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 short cmdtype; /* index identifying command */
88 char rehash; /* if set, cd done since entry created */
89 char cmdname[ARB]; /* name of command */
93 STATIC struct tblentry *cmdtable[CMDTABLESIZE];
94 STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */
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(char *, int);
101 STATIC void delete_cmd_entry(void);
106 * Exec a program. Never returns. If you change this routine, you may
107 * have to change the find_command routine as well.
111 shellexec(char **argv, char **envp, char *path, int index)
116 if (strchr(argv[0], '/') != NULL) {
117 tryexec(argv[0], argv, envp);
121 while ((cmdname = padvance(&path, argv[0])) != NULL) {
122 if (--index < 0 && pathopt == NULL) {
123 tryexec(cmdname, argv, envp);
124 if (errno != ENOENT && errno != ENOTDIR)
131 /* Map to POSIX errors */
143 if (e == ENOENT || e == ENOTDIR)
144 exerror(EXEXEC, "%s: not found", argv[0]);
145 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
150 tryexec(char *cmd, char **argv, char **envp)
154 execve(cmd, argv, envp);
158 setinputfile(cmd, 0);
159 commandname = arg0 = savestr(argv[0]);
161 exraise(EXSHELLPROC);
168 * Do a path search. The variable path (passed by reference) should be
169 * set to the start of the path before the first call; padvance will update
170 * this value as it proceeds. Successive calls to padvance will return
171 * the possible path expansions in sequence. If an option (indicated by
172 * a percent sign) appears in the path entry then the global variable
173 * pathopt will be set to point to it; otherwise pathopt will be set to
180 padvance(char **path, char *name)
189 for (p = start ; *p && *p != ':' && *p != '%' ; p++);
190 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
191 while (stackblocksize() < len)
195 memcpy(q, start, p - start);
203 while (*p && *p != ':') p++;
214 /*** Command hashing code ***/
218 hashcmd(int argc __unused, char **argv __unused)
220 struct tblentry **pp;
221 struct tblentry *cmdp;
224 struct cmdentry entry;
228 while ((c = nextopt("rv")) != '\0') {
231 } else if (c == 'v') {
235 if (*argptr == NULL) {
236 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
237 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
238 if (cmdp->cmdtype == CMDNORMAL)
239 printentry(cmdp, verbose);
244 while ((name = *argptr) != NULL) {
245 if ((cmdp = cmdlookup(name, 0)) != NULL
246 && (cmdp->cmdtype == CMDNORMAL
247 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)))
249 find_command(name, &entry, 1, pathval());
251 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
252 cmdp = cmdlookup(name, 0);
254 printentry(cmdp, verbose);
256 outfmt(&errout, "%s: not found\n", name);
267 printentry(struct tblentry *cmdp, int verbose)
273 if (cmdp->cmdtype == CMDNORMAL) {
274 index = cmdp->param.index;
277 name = padvance(&path, cmdp->cmdname);
279 } while (--index >= 0);
281 } else if (cmdp->cmdtype == CMDBUILTIN) {
282 out1fmt("builtin %s", cmdp->cmdname);
283 } else if (cmdp->cmdtype == CMDFUNCTION) {
284 out1fmt("function %s", cmdp->cmdname);
287 name = commandtext(cmdp->param.func);
295 error("internal error: cmdtype %d", cmdp->cmdtype);
306 * Resolve a command name. If you change this routine, you may have to
307 * change the shellexec routine as well.
311 find_command(char *name, struct cmdentry *entry, int printerr, char *path)
313 struct tblentry *cmdp;
321 /* If name contains a slash, don't use the hash table */
322 if (strchr(name, '/') != NULL) {
323 entry->cmdtype = CMDNORMAL;
328 /* If name is in the table, and not invalidated by cd, we're done */
329 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0)
332 /* If %builtin not in path, check for builtin next */
333 if (builtinloc < 0 && (i = find_builtin(name)) >= 0) {
335 cmdp = cmdlookup(name, 1);
336 cmdp->cmdtype = CMDBUILTIN;
337 cmdp->param.index = i;
342 /* We have to search path. */
343 prev = -1; /* where to start */
344 if (cmdp) { /* doing a rehash */
345 if (cmdp->cmdtype == CMDBUILTIN)
348 prev = cmdp->param.index;
354 while ((fullname = padvance(&path, name)) != NULL) {
358 if (prefix("builtin", pathopt)) {
359 if ((i = find_builtin(name)) < 0)
362 cmdp = cmdlookup(name, 1);
363 cmdp->cmdtype = CMDBUILTIN;
364 cmdp->param.index = i;
367 } else if (prefix("func", pathopt)) {
370 goto loop; /* ignore unimplemented options */
373 /* if rehash, don't redo absolute path names */
374 if (fullname[0] == '/' && index <= prev) {
377 TRACE(("searchexec \"%s\": no change\n", name));
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 (pathopt) { /* this is a %func directory */
389 stalloc(strlen(fullname) + 1);
390 readcmdfile(fullname);
391 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
392 error("%s not defined in %s", name, fullname);
397 if (statb.st_uid == geteuid()) {
398 if ((statb.st_mode & 0100) == 0)
400 } else if (statb.st_gid == getegid()) {
401 if ((statb.st_mode & 010) == 0)
404 if ((statb.st_mode & 01) == 0)
408 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
410 cmdp = cmdlookup(name, 1);
411 cmdp->cmdtype = CMDNORMAL;
412 cmdp->param.index = index;
417 /* We failed. If there was an entry for this command, delete it */
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;
431 entry->cmdtype = cmdp->cmdtype;
432 entry->u = cmdp->param;
438 * Search the table of builtin commands.
442 find_builtin(char *name)
444 const struct builtincmd *bp;
446 for (bp = builtincmd ; bp->name ; bp++) {
447 if (*bp->name == *name && equal(bp->name, name))
456 * Called when a cd is done. Marks all commands so the next time they
457 * are executed they will be rehashed.
463 struct tblentry **pp;
464 struct tblentry *cmdp;
466 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
467 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
468 if (cmdp->cmdtype == CMDNORMAL
469 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
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)
486 const char *old, *new;
493 firstchange = 9999; /* assume no change */
499 if ((*old == '\0' && *new == ':')
500 || (*old == ':' && *new == '\0'))
502 old = new; /* ignore subsequent differences */
506 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
513 if (builtinloc < 0 && bltin >= 0)
514 builtinloc = bltin; /* zap builtins */
515 if (builtinloc >= 0 && bltin < 0)
517 clearcmdentry(firstchange);
523 * Clear out command entries. The argument specifies the first entry in
524 * PATH which has changed.
528 clearcmdentry(int firstchange)
530 struct tblentry **tblp;
531 struct tblentry **pp;
532 struct tblentry *cmdp;
535 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
537 while ((cmdp = *pp) != NULL) {
538 if ((cmdp->cmdtype == CMDNORMAL &&
539 cmdp->param.index >= firstchange)
540 || (cmdp->cmdtype == CMDBUILTIN &&
541 builtinloc >= firstchange)) {
554 * Delete all functions.
558 MKINIT void deletefuncs(void);
568 struct tblentry **tblp;
569 struct tblentry **pp;
570 struct tblentry *cmdp;
573 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
575 while ((cmdp = *pp) != NULL) {
576 if (cmdp->cmdtype == CMDFUNCTION) {
578 freefunc(cmdp->param.func);
591 * Locate a command in the command hash table. If "add" is nonzero,
592 * add the command to the table if it is not already present. The
593 * variable "lastcmdentry" is set to point to the address of the link
594 * pointing to the entry, so that delete_cmd_entry can delete the
598 STATIC struct tblentry **lastcmdentry;
601 STATIC struct tblentry *
602 cmdlookup(char *name, int add)
606 struct tblentry *cmdp;
607 struct tblentry **pp;
614 pp = &cmdtable[hashval % CMDTABLESIZE];
615 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
616 if (equal(cmdp->cmdname, name))
620 if (add && cmdp == NULL) {
622 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
625 cmdp->cmdtype = CMDUNKNOWN;
627 strcpy(cmdp->cmdname, name);
635 * Delete the command entry returned on the last lookup.
639 delete_cmd_entry(void)
641 struct tblentry *cmdp;
644 cmdp = *lastcmdentry;
645 *lastcmdentry = cmdp->next;
653 * Add a new command entry, replacing any existing command entry for
658 addcmdentry(char *name, struct cmdentry *entry)
660 struct tblentry *cmdp;
663 cmdp = cmdlookup(name, 1);
664 if (cmdp->cmdtype == CMDFUNCTION) {
665 freefunc(cmdp->param.func);
667 cmdp->cmdtype = entry->cmdtype;
668 cmdp->param = entry->u;
674 * Define a shell function.
678 defun(char *name, union node *func)
680 struct cmdentry entry;
683 entry.cmdtype = CMDFUNCTION;
684 entry.u.func = copyfunc(func);
685 addcmdentry(name, &entry);
691 * Delete a function if it exists.
695 unsetfunc(char *name)
697 struct tblentry *cmdp;
699 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
700 freefunc(cmdp->param.func);
708 * Locate and print what a word is...
712 typecmd(int argc, char **argv)
714 struct cmdentry entry;
715 struct tblentry *cmdp;
720 extern char *const parsekwd[];
722 for (i = 1; i < argc; i++) {
724 /* First look at the keywords */
725 for (pp = (char **)parsekwd; *pp; pp++)
726 if (**pp == *argv[i] && equal(*pp, argv[i]))
730 out1str(" is a shell keyword\n");
734 /* Then look at the aliases */
735 if ((ap = lookupalias(argv[i], 1)) != NULL) {
736 out1fmt(" is an alias for %s\n", ap->val);
740 /* Then check if it is a tracked alias */
741 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
742 entry.cmdtype = cmdp->cmdtype;
743 entry.u = cmdp->param;
746 /* Finally use brute force */
747 find_command(argv[i], &entry, 0, pathval());
750 switch (entry.cmdtype) {
752 if (strchr(argv[i], '/') == NULL) {
753 char *path = pathval(), *name;
754 int j = entry.u.index;
756 name = padvance(&path, argv[i]);
759 out1fmt(" is%s %s\n",
760 cmdp ? " a tracked alias for" : "", name);
762 if (access(argv[i], X_OK) == 0)
763 out1fmt(" is %s\n", argv[i]);
765 out1fmt(": %s\n", strerror(errno));
770 out1str(" is a shell function\n");
774 out1str(" is a shell builtin\n");
778 out1str(": not found\n");