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 */
94 int exerrno = 0; /* Last exec error */
97 static void tryexec(char *, char **, char **);
98 static void printentry(struct tblentry *, int);
99 static struct tblentry *cmdlookup(const char *, int);
100 static void delete_cmd_entry(void);
101 static void addcmdentry(const char *, struct cmdentry *);
106 * Exec a program. Never returns. If you change this routine, you may
107 * have to change the find_command routine as well.
109 * The argv array may be changed and element argv[-1] should be writable.
113 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, argv[0])) != NULL) {
124 if (--idx < 0 && pathopt == NULL) {
125 tryexec(cmdname, argv, envp);
126 if (errno != ENOENT && errno != ENOTDIR)
135 /* Map to POSIX errors */
136 if (e == ENOENT || e == ENOTDIR) {
138 exerror(EXEXEC, "%s: not found", argv[0]);
141 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
147 tryexec(char *cmd, char **argv, char **envp)
153 execve(cmd, argv, envp);
157 in = open(cmd, O_RDONLY | O_NONBLOCK);
159 n = pread(in, buf, sizeof buf, 0);
161 if (n > 0 && memchr(buf, '\0', n) != NULL) {
167 *--argv = __DECONST(char *, _PATH_BSHELL);
168 execve(_PATH_BSHELL, argv, envp);
174 * Do a path search. The variable path (passed by reference) should be
175 * set to the start of the path before the first call; padvance will update
176 * this value as it proceeds. Successive calls to padvance will return
177 * the possible path expansions in sequence. If an option (indicated by
178 * a percent sign) appears in the path entry then the global variable
179 * pathopt will be set to point to it; otherwise pathopt will be set to
186 padvance(const char **path, const char *name)
188 const char *p, *start;
195 for (p = start; *p && *p != ':' && *p != '%'; p++)
197 namelen = strlen(name);
198 len = p - start + namelen + 2; /* "2" is for '/' and '\0' */
200 CHECKSTRSPACE(len, q);
202 memcpy(q, start, p - start);
206 memcpy(q, name, namelen + 1);
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;
237 while ((c = nextopt("rv")) != '\0') {
240 } else if (c == 'v') {
244 if (*argptr == NULL) {
245 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
246 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
247 if (cmdp->cmdtype == CMDNORMAL)
248 printentry(cmdp, verbose);
253 while ((name = *argptr) != NULL) {
254 if ((cmdp = cmdlookup(name, 0)) != NULL
255 && cmdp->cmdtype == CMDNORMAL)
257 find_command(name, &entry, DO_ERR, pathval());
258 if (entry.cmdtype == CMDUNKNOWN)
261 cmdp = cmdlookup(name, 0);
263 printentry(cmdp, verbose);
265 outfmt(out2, "%s: not found\n", name);
277 printentry(struct tblentry *cmdp, int verbose)
283 if (cmdp->cmdtype == CMDNORMAL) {
284 idx = cmdp->param.index;
287 name = padvance(&path, cmdp->cmdname);
289 } while (--idx >= 0);
291 } else if (cmdp->cmdtype == CMDBUILTIN) {
292 out1fmt("builtin %s", cmdp->cmdname);
293 } else if (cmdp->cmdtype == CMDFUNCTION) {
294 out1fmt("function %s", cmdp->cmdname);
297 name = commandtext(getfuncnode(cmdp->param.func));
305 error("internal error: cmdtype %d", cmdp->cmdtype);
314 * Resolve a command name. If you change this routine, you may have to
315 * change the shellexec routine as well.
319 find_command(const char *name, struct cmdentry *entry, int act,
322 struct tblentry *cmdp, loc_cmd;
331 /* If name contains a slash, don't use the hash table */
332 if (strchr(name, '/') != NULL) {
333 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) {
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. */
366 for (;(fullname = padvance(&path, name)) != NULL; stunalloc(fullname)) {
369 if (strncmp(pathopt, "func", 4) == 0) {
372 continue; /* ignore unimplemented options */
375 if (fullname[0] != '/')
377 if (stat(fullname, &statb) < 0) {
378 if (errno != ENOENT && errno != ENOTDIR)
382 e = EACCES; /* if we fail, this will be the error */
383 if (!S_ISREG(statb.st_mode))
385 if (pathopt) { /* this is a %func directory */
386 readcmdfile(fullname);
387 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
388 error("%s not defined in %s", name, fullname);
393 if (statb.st_uid == geteuid()) {
394 if ((statb.st_mode & 0100) == 0)
396 } else if (statb.st_gid == getegid()) {
397 if ((statb.st_mode & 010) == 0)
400 if ((statb.st_mode & 01) == 0)
404 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
407 cmdp = cmdlookup(name, 1);
408 if (cmdp->cmdtype == CMDFUNCTION)
410 cmdp->cmdtype = CMDNORMAL;
411 cmdp->param.index = idx;
418 if (e == ENOENT || e == ENOTDIR)
419 outfmt(out2, "%s: not found\n", name);
421 outfmt(out2, "%s: %s\n", name, strerror(e));
423 entry->cmdtype = CMDUNKNOWN;
431 entry->cmdtype = cmdp->cmdtype;
432 entry->u = cmdp->param;
433 entry->special = cmdp->special;
439 * Search the table of builtin commands.
443 find_builtin(const char *name, int *special)
445 const unsigned char *bp;
449 for (bp = builtincmd ; *bp ; bp += 2 + bp[0]) {
450 if (bp[0] == len && memcmp(bp + 2, name, len) == 0) {
451 *special = (bp[1] & BUILTIN_SPECIAL) != 0;
452 return bp[1] & ~BUILTIN_SPECIAL;
461 * Called when a cd is done. If any entry in cmdtable depends on the current
462 * directory, simply clear cmdtable completely.
475 * Called before PATH is changed. The argument is the new value of PATH;
476 * pathval() still returns the old value at this point. Called with
481 changepath(const char *newval __unused)
488 * Clear out command entries. The argument specifies the first entry in
489 * PATH which has changed.
495 struct tblentry **tblp;
496 struct tblentry **pp;
497 struct tblentry *cmdp;
500 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
502 while ((cmdp = *pp) != NULL) {
503 if (cmdp->cmdtype == CMDNORMAL) {
517 * Locate a command in the command hash table. If "add" is nonzero,
518 * add the command to the table if it is not already present. The
519 * variable "lastcmdentry" is set to point to the address of the link
520 * pointing to the entry, so that delete_cmd_entry can delete the
524 static struct tblentry **lastcmdentry;
527 static struct tblentry *
528 cmdlookup(const char *name, int add)
530 unsigned int hashval;
532 struct tblentry *cmdp;
533 struct tblentry **pp;
537 hashval = (unsigned char)*p << 4;
540 pp = &cmdtable[hashval % CMDTABLESIZE];
541 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
542 if (equal(cmdp->cmdname, name))
546 if (add && cmdp == NULL) {
549 cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1);
551 cmdp->cmdtype = CMDUNKNOWN;
552 memcpy(cmdp->cmdname, name, len + 1);
560 * Delete the command entry returned on the last lookup.
564 delete_cmd_entry(void)
566 struct tblentry *cmdp;
569 cmdp = *lastcmdentry;
570 *lastcmdentry = cmdp->next;
578 * Add a new command entry, replacing any existing command entry for
583 addcmdentry(const char *name, struct cmdentry *entry)
585 struct tblentry *cmdp;
588 cmdp = cmdlookup(name, 1);
589 if (cmdp->cmdtype == CMDFUNCTION) {
590 unreffunc(cmdp->param.func);
592 cmdp->cmdtype = entry->cmdtype;
593 cmdp->param = entry->u;
594 cmdp->special = entry->special;
600 * Define a shell function.
604 defun(const char *name, union node *func)
606 struct cmdentry entry;
609 entry.cmdtype = CMDFUNCTION;
610 entry.u.func = copyfunc(func);
612 addcmdentry(name, &entry);
618 * Delete a function if it exists.
619 * Called with interrupts off.
623 unsetfunc(const char *name)
625 struct tblentry *cmdp;
627 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
628 unreffunc(cmdp->param.func);
637 * Check if a function by a certain name exists.
640 isfunc(const char *name)
642 struct tblentry *cmdp;
643 cmdp = cmdlookup(name, 0);
644 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
649 * Shared code for the following builtin commands:
650 * type, command -v, command -V
654 typecmd_impl(int argc, char **argv, int cmd, const char *path)
656 struct cmdentry entry;
657 struct tblentry *cmdp;
658 const char *const *pp;
663 if (path != pathval())
666 for (i = 1; i < argc; i++) {
667 /* First look at the keywords */
668 for (pp = parsekwd; *pp; pp++)
669 if (**pp == *argv[i] && equal(*pp, argv[i]))
673 if (cmd == TYPECMD_SMALLV)
674 out1fmt("%s\n", argv[i]);
676 out1fmt("%s is a shell keyword\n", argv[i]);
680 /* Then look at the aliases */
681 if ((ap = lookupalias(argv[i], 1)) != NULL) {
682 if (cmd == TYPECMD_SMALLV) {
683 out1fmt("alias %s=", argv[i]);
685 outcslow('\n', out1);
687 out1fmt("%s is an alias for %s\n", argv[i],
692 /* Then check if it is a tracked alias */
693 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
694 entry.cmdtype = cmdp->cmdtype;
695 entry.u = cmdp->param;
696 entry.special = cmdp->special;
699 /* Finally use brute force */
700 find_command(argv[i], &entry, 0, path);
703 switch (entry.cmdtype) {
705 if (strchr(argv[i], '/') == NULL) {
706 const char *path2 = path;
708 int j = entry.u.index;
710 name = padvance(&path2, argv[i]);
713 if (cmd == TYPECMD_SMALLV)
714 out1fmt("%s\n", name);
716 out1fmt("%s is%s %s\n", argv[i],
717 (cmdp && cmd == TYPECMD_TYPE) ?
718 " a tracked alias for" : "",
721 if (eaccess(argv[i], X_OK) == 0) {
722 if (cmd == TYPECMD_SMALLV)
723 out1fmt("%s\n", argv[i]);
725 out1fmt("%s is %s\n", argv[i],
728 if (cmd != TYPECMD_SMALLV)
729 outfmt(out2, "%s: %s\n",
730 argv[i], strerror(errno));
737 if (cmd == TYPECMD_SMALLV)
738 out1fmt("%s\n", argv[i]);
740 out1fmt("%s is a shell function\n", argv[i]);
744 if (cmd == TYPECMD_SMALLV)
745 out1fmt("%s\n", argv[i]);
746 else if (entry.special)
747 out1fmt("%s is a special shell builtin\n",
750 out1fmt("%s is a shell builtin\n", argv[i]);
754 if (cmd != TYPECMD_SMALLV)
755 outfmt(out2, "%s: not found\n", argv[i]);
761 if (path != pathval())
768 * Locate and print what a word is...
772 typecmd(int argc, char **argv)
774 if (argc > 2 && strcmp(argv[1], "--") == 0)
776 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));