xref: /freebsd/bin/sh/exec.c (revision 09e8dea79366f1e5b3a73e8a271b26e4b6bf2e6a)
1 /*-
2  * Copyright (c) 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Kenneth Almquist.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #ifndef lint
38 #if 0
39 static char sccsid[] = "@(#)exec.c	8.4 (Berkeley) 6/8/95";
40 #endif
41 static const char rcsid[] =
42   "$FreeBSD$";
43 #endif /* not lint */
44 
45 #include <sys/types.h>
46 #include <sys/stat.h>
47 #include <unistd.h>
48 #include <fcntl.h>
49 #include <errno.h>
50 #include <stdlib.h>
51 
52 /*
53  * When commands are first encountered, they are entered in a hash table.
54  * This ensures that a full path search will not have to be done for them
55  * on each invocation.
56  *
57  * We should investigate converting to a linear search, even though that
58  * would make the command name "hash" a misnomer.
59  */
60 
61 #include "shell.h"
62 #include "main.h"
63 #include "nodes.h"
64 #include "parser.h"
65 #include "redir.h"
66 #include "eval.h"
67 #include "exec.h"
68 #include "builtins.h"
69 #include "var.h"
70 #include "options.h"
71 #include "input.h"
72 #include "output.h"
73 #include "syntax.h"
74 #include "memalloc.h"
75 #include "error.h"
76 #include "init.h"
77 #include "mystring.h"
78 #include "show.h"
79 #include "jobs.h"
80 #include "alias.h"
81 
82 
83 #define CMDTABLESIZE 31		/* should be prime */
84 #define ARB 1			/* actual size determined at run time */
85 
86 
87 
88 struct tblentry {
89 	struct tblentry *next;	/* next entry in hash chain */
90 	union param param;	/* definition of builtin function */
91 	short cmdtype;		/* index identifying command */
92 	char rehash;		/* if set, cd done since entry created */
93 	char cmdname[ARB];	/* name of command */
94 };
95 
96 
97 STATIC struct tblentry *cmdtable[CMDTABLESIZE];
98 STATIC int builtinloc = -1;		/* index in path of %builtin, or -1 */
99 int exerrno = 0;			/* Last exec error */
100 
101 
102 STATIC void tryexec(char *, char **, char **);
103 #ifndef BSD
104 STATIC void execinterp(char **, char **);
105 #endif
106 STATIC void printentry(struct tblentry *, int);
107 STATIC struct tblentry *cmdlookup(char *, int);
108 STATIC void delete_cmd_entry(void);
109 
110 
111 
112 /*
113  * Exec a program.  Never returns.  If you change this routine, you may
114  * have to change the find_command routine as well.
115  */
116 
117 void
118 shellexec(char **argv, char **envp, char *path, int index)
119 {
120 	char *cmdname;
121 	int e;
122 
123 	if (strchr(argv[0], '/') != NULL) {
124 		tryexec(argv[0], argv, envp);
125 		e = errno;
126 	} else {
127 		e = ENOENT;
128 		while ((cmdname = padvance(&path, argv[0])) != NULL) {
129 			if (--index < 0 && pathopt == NULL) {
130 				tryexec(cmdname, argv, envp);
131 				if (errno != ENOENT && errno != ENOTDIR)
132 					e = errno;
133 			}
134 			stunalloc(cmdname);
135 		}
136 	}
137 
138 	/* Map to POSIX errors */
139 	switch (e) {
140 	case EACCES:
141 		exerrno = 126;
142 		break;
143 	case ENOENT:
144 		exerrno = 127;
145 		break;
146 	default:
147 		exerrno = 2;
148 		break;
149 	}
150 	exerror(EXEXEC, "%s: %s", argv[0], errmsg(e, E_EXEC));
151 }
152 
153 
154 STATIC void
155 tryexec(char *cmd, char **argv, char **envp)
156 {
157 	int e;
158 #ifndef BSD
159 	char *p;
160 #endif
161 
162 #ifdef SYSV
163 	do {
164 		execve(cmd, argv, envp);
165 	} while (errno == EINTR);
166 #else
167 	execve(cmd, argv, envp);
168 #endif
169 	e = errno;
170 	if (e == ENOEXEC) {
171 		initshellproc();
172 		setinputfile(cmd, 0);
173 		commandname = arg0 = savestr(argv[0]);
174 #ifndef BSD
175 		pgetc(); pungetc();		/* fill up input buffer */
176 		p = parsenextc;
177 		if (parsenleft > 2 && p[0] == '#' && p[1] == '!') {
178 			argv[0] = cmd;
179 			execinterp(argv, envp);
180 		}
181 #endif
182 		setparam(argv + 1);
183 		exraise(EXSHELLPROC);
184 		/*NOTREACHED*/
185 	}
186 	errno = e;
187 }
188 
189 
190 #ifndef BSD
191 /*
192  * Execute an interpreter introduced by "#!", for systems where this
193  * feature has not been built into the kernel.  If the interpreter is
194  * the shell, return (effectively ignoring the "#!").  If the execution
195  * of the interpreter fails, exit.
196  *
197  * This code peeks inside the input buffer in order to avoid actually
198  * reading any input.  It would benefit from a rewrite.
199  */
200 
201 #define NEWARGS 5
202 
203 STATIC void
204 execinterp(char **argv, char **envp)
205 {
206 	int n;
207 	char *inp;
208 	char *outp;
209 	char c;
210 	char *p;
211 	char **ap;
212 	char *newargs[NEWARGS];
213 	int i;
214 	char **ap2;
215 	char **new;
216 
217 	n = parsenleft - 2;
218 	inp = parsenextc + 2;
219 	ap = newargs;
220 	for (;;) {
221 		while (--n >= 0 && (*inp == ' ' || *inp == '\t'))
222 			inp++;
223 		if (n < 0)
224 			goto bad;
225 		if ((c = *inp++) == '\n')
226 			break;
227 		if (ap == &newargs[NEWARGS])
228 bad:		  error("Bad #! line");
229 		STARTSTACKSTR(outp);
230 		do {
231 			STPUTC(c, outp);
232 		} while (--n >= 0 && (c = *inp++) != ' ' && c != '\t' && c != '\n');
233 		STPUTC('\0', outp);
234 		n++, inp--;
235 		*ap++ = grabstackstr(outp);
236 	}
237 	if (ap == newargs + 1) {	/* if no args, maybe no exec is needed */
238 		p = newargs[0];
239 		for (;;) {
240 			if (equal(p, "sh") || equal(p, "ash")) {
241 				return;
242 			}
243 			while (*p != '/') {
244 				if (*p == '\0')
245 					goto break2;
246 				p++;
247 			}
248 			p++;
249 		}
250 break2:;
251 	}
252 	i = (char *)ap - (char *)newargs;		/* size in bytes */
253 	if (i == 0)
254 		error("Bad #! line");
255 	for (ap2 = argv ; *ap2++ != NULL ; );
256 	new = ckmalloc(i + ((char *)ap2 - (char *)argv));
257 	ap = newargs, ap2 = new;
258 	while ((i -= sizeof (char **)) >= 0)
259 		*ap2++ = *ap++;
260 	ap = argv;
261 	while (*ap2++ = *ap++);
262 	shellexec(new, envp, pathval(), 0);
263 }
264 #endif
265 
266 
267 
268 /*
269  * Do a path search.  The variable path (passed by reference) should be
270  * set to the start of the path before the first call; padvance will update
271  * this value as it proceeds.  Successive calls to padvance will return
272  * the possible path expansions in sequence.  If an option (indicated by
273  * a percent sign) appears in the path entry then the global variable
274  * pathopt will be set to point to it; otherwise pathopt will be set to
275  * NULL.
276  */
277 
278 char *pathopt;
279 
280 char *
281 padvance(char **path, char *name)
282 {
283 	char *p, *q;
284 	char *start;
285 	int len;
286 
287 	if (*path == NULL)
288 		return NULL;
289 	start = *path;
290 	for (p = start ; *p && *p != ':' && *p != '%' ; p++);
291 	len = p - start + strlen(name) + 2;	/* "2" is for '/' and '\0' */
292 	while (stackblocksize() < len)
293 		growstackblock();
294 	q = stackblock();
295 	if (p != start) {
296 		memcpy(q, start, p - start);
297 		q += p - start;
298 		*q++ = '/';
299 	}
300 	strcpy(q, name);
301 	pathopt = NULL;
302 	if (*p == '%') {
303 		pathopt = ++p;
304 		while (*p && *p != ':')  p++;
305 	}
306 	if (*p == ':')
307 		*path = p + 1;
308 	else
309 		*path = NULL;
310 	return stalloc(len);
311 }
312 
313 
314 
315 /*** Command hashing code ***/
316 
317 
318 int
319 hashcmd(int argc __unused, char **argv __unused)
320 {
321 	struct tblentry **pp;
322 	struct tblentry *cmdp;
323 	int c;
324 	int verbose;
325 	struct cmdentry entry;
326 	char *name;
327 
328 	verbose = 0;
329 	while ((c = nextopt("rv")) != '\0') {
330 		if (c == 'r') {
331 			clearcmdentry(0);
332 		} else if (c == 'v') {
333 			verbose++;
334 		}
335 	}
336 	if (*argptr == NULL) {
337 		for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
338 			for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
339 				if (cmdp->cmdtype == CMDNORMAL)
340 					printentry(cmdp, verbose);
341 			}
342 		}
343 		return 0;
344 	}
345 	while ((name = *argptr) != NULL) {
346 		if ((cmdp = cmdlookup(name, 0)) != NULL
347 		 && (cmdp->cmdtype == CMDNORMAL
348 		     || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)))
349 			delete_cmd_entry();
350 		find_command(name, &entry, 1, pathval());
351 		if (verbose) {
352 			if (entry.cmdtype != CMDUNKNOWN) {	/* if no error msg */
353 				cmdp = cmdlookup(name, 0);
354 				if (cmdp != NULL)
355 					printentry(cmdp, verbose);
356 				else
357 					outfmt(&errout, "%s: not found\n", name);
358 			}
359 			flushall();
360 		}
361 		argptr++;
362 	}
363 	return 0;
364 }
365 
366 
367 STATIC void
368 printentry(struct tblentry *cmdp, int verbose)
369 {
370 	int index;
371 	char *path;
372 	char *name;
373 
374 	if (cmdp->cmdtype == CMDNORMAL) {
375 		index = cmdp->param.index;
376 		path = pathval();
377 		do {
378 			name = padvance(&path, cmdp->cmdname);
379 			stunalloc(name);
380 		} while (--index >= 0);
381 		out1str(name);
382 	} else if (cmdp->cmdtype == CMDBUILTIN) {
383 		out1fmt("builtin %s", cmdp->cmdname);
384 	} else if (cmdp->cmdtype == CMDFUNCTION) {
385 		out1fmt("function %s", cmdp->cmdname);
386 		if (verbose) {
387 			INTOFF;
388 			name = commandtext(cmdp->param.func);
389 			out1c(' ');
390 			out1str(name);
391 			ckfree(name);
392 			INTON;
393 		}
394 #ifdef DEBUG
395 	} else {
396 		error("internal error: cmdtype %d", cmdp->cmdtype);
397 #endif
398 	}
399 	if (cmdp->rehash)
400 		out1c('*');
401 	out1c('\n');
402 }
403 
404 
405 
406 /*
407  * Resolve a command name.  If you change this routine, you may have to
408  * change the shellexec routine as well.
409  */
410 
411 void
412 find_command(char *name, struct cmdentry *entry, int printerr, char *path)
413 {
414 	struct tblentry *cmdp;
415 	int index;
416 	int prev;
417 	char *fullname;
418 	struct stat statb;
419 	int e;
420 	int i;
421 
422 	/* If name contains a slash, don't use the hash table */
423 	if (strchr(name, '/') != NULL) {
424 		entry->cmdtype = CMDNORMAL;
425 		entry->u.index = 0;
426 		return;
427 	}
428 
429 	/* If name is in the table, and not invalidated by cd, we're done */
430 	if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0)
431 		goto success;
432 
433 	/* If %builtin not in path, check for builtin next */
434 	if (builtinloc < 0 && (i = find_builtin(name)) >= 0) {
435 		INTOFF;
436 		cmdp = cmdlookup(name, 1);
437 		cmdp->cmdtype = CMDBUILTIN;
438 		cmdp->param.index = i;
439 		INTON;
440 		goto success;
441 	}
442 
443 	/* We have to search path. */
444 	prev = -1;		/* where to start */
445 	if (cmdp) {		/* doing a rehash */
446 		if (cmdp->cmdtype == CMDBUILTIN)
447 			prev = builtinloc;
448 		else
449 			prev = cmdp->param.index;
450 	}
451 
452 	e = ENOENT;
453 	index = -1;
454 loop:
455 	while ((fullname = padvance(&path, name)) != NULL) {
456 		stunalloc(fullname);
457 		index++;
458 		if (pathopt) {
459 			if (prefix("builtin", pathopt)) {
460 				if ((i = find_builtin(name)) < 0)
461 					goto loop;
462 				INTOFF;
463 				cmdp = cmdlookup(name, 1);
464 				cmdp->cmdtype = CMDBUILTIN;
465 				cmdp->param.index = i;
466 				INTON;
467 				goto success;
468 			} else if (prefix("func", pathopt)) {
469 				/* handled below */
470 			} else {
471 				goto loop;	/* ignore unimplemented options */
472 			}
473 		}
474 		/* if rehash, don't redo absolute path names */
475 		if (fullname[0] == '/' && index <= prev) {
476 			if (index < prev)
477 				goto loop;
478 			TRACE(("searchexec \"%s\": no change\n", name));
479 			goto success;
480 		}
481 		while (stat(fullname, &statb) < 0) {
482 #ifdef SYSV
483 			if (errno == EINTR)
484 				continue;
485 #endif
486 			if (errno != ENOENT && errno != ENOTDIR)
487 				e = errno;
488 			goto loop;
489 		}
490 		e = EACCES;	/* if we fail, this will be the error */
491 		if (!S_ISREG(statb.st_mode))
492 			goto loop;
493 		if (pathopt) {		/* this is a %func directory */
494 			stalloc(strlen(fullname) + 1);
495 			readcmdfile(fullname);
496 			if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
497 				error("%s not defined in %s", name, fullname);
498 			stunalloc(fullname);
499 			goto success;
500 		}
501 #ifdef notdef
502 		if (statb.st_uid == geteuid()) {
503 			if ((statb.st_mode & 0100) == 0)
504 				goto loop;
505 		} else if (statb.st_gid == getegid()) {
506 			if ((statb.st_mode & 010) == 0)
507 				goto loop;
508 		} else {
509 			if ((statb.st_mode & 01) == 0)
510 				goto loop;
511 		}
512 #endif
513 		TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
514 		INTOFF;
515 		cmdp = cmdlookup(name, 1);
516 		cmdp->cmdtype = CMDNORMAL;
517 		cmdp->param.index = index;
518 		INTON;
519 		goto success;
520 	}
521 
522 	/* We failed.  If there was an entry for this command, delete it */
523 	if (cmdp)
524 		delete_cmd_entry();
525 	if (printerr)
526 		outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC));
527 	entry->cmdtype = CMDUNKNOWN;
528 	return;
529 
530 success:
531 	cmdp->rehash = 0;
532 	entry->cmdtype = cmdp->cmdtype;
533 	entry->u = cmdp->param;
534 }
535 
536 
537 
538 /*
539  * Search the table of builtin commands.
540  */
541 
542 int
543 find_builtin(char *name)
544 {
545 	const struct builtincmd *bp;
546 
547 	for (bp = builtincmd ; bp->name ; bp++) {
548 		if (*bp->name == *name && equal(bp->name, name))
549 			return bp->code;
550 	}
551 	return -1;
552 }
553 
554 
555 
556 /*
557  * Called when a cd is done.  Marks all commands so the next time they
558  * are executed they will be rehashed.
559  */
560 
561 void
562 hashcd(void)
563 {
564 	struct tblentry **pp;
565 	struct tblentry *cmdp;
566 
567 	for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
568 		for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
569 			if (cmdp->cmdtype == CMDNORMAL
570 			 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
571 				cmdp->rehash = 1;
572 		}
573 	}
574 }
575 
576 
577 
578 /*
579  * Called before PATH is changed.  The argument is the new value of PATH;
580  * pathval() still returns the old value at this point.  Called with
581  * interrupts off.
582  */
583 
584 void
585 changepath(const char *newval)
586 {
587 	const char *old, *new;
588 	int index;
589 	int firstchange;
590 	int bltin;
591 
592 	old = pathval();
593 	new = newval;
594 	firstchange = 9999;	/* assume no change */
595 	index = 0;
596 	bltin = -1;
597 	for (;;) {
598 		if (*old != *new) {
599 			firstchange = index;
600 			if ((*old == '\0' && *new == ':')
601 			 || (*old == ':' && *new == '\0'))
602 				firstchange++;
603 			old = new;	/* ignore subsequent differences */
604 		}
605 		if (*new == '\0')
606 			break;
607 		if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
608 			bltin = index;
609 		if (*new == ':') {
610 			index++;
611 		}
612 		new++, old++;
613 	}
614 	if (builtinloc < 0 && bltin >= 0)
615 		builtinloc = bltin;		/* zap builtins */
616 	if (builtinloc >= 0 && bltin < 0)
617 		firstchange = 0;
618 	clearcmdentry(firstchange);
619 	builtinloc = bltin;
620 }
621 
622 
623 /*
624  * Clear out command entries.  The argument specifies the first entry in
625  * PATH which has changed.
626  */
627 
628 void
629 clearcmdentry(int firstchange)
630 {
631 	struct tblentry **tblp;
632 	struct tblentry **pp;
633 	struct tblentry *cmdp;
634 
635 	INTOFF;
636 	for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
637 		pp = tblp;
638 		while ((cmdp = *pp) != NULL) {
639 			if ((cmdp->cmdtype == CMDNORMAL &&
640 			     cmdp->param.index >= firstchange)
641 			 || (cmdp->cmdtype == CMDBUILTIN &&
642 			     builtinloc >= firstchange)) {
643 				*pp = cmdp->next;
644 				ckfree(cmdp);
645 			} else {
646 				pp = &cmdp->next;
647 			}
648 		}
649 	}
650 	INTON;
651 }
652 
653 
654 /*
655  * Delete all functions.
656  */
657 
658 #ifdef mkinit
659 MKINIT void deletefuncs();
660 
661 SHELLPROC {
662 	deletefuncs();
663 }
664 #endif
665 
666 void
667 deletefuncs(void)
668 {
669 	struct tblentry **tblp;
670 	struct tblentry **pp;
671 	struct tblentry *cmdp;
672 
673 	INTOFF;
674 	for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
675 		pp = tblp;
676 		while ((cmdp = *pp) != NULL) {
677 			if (cmdp->cmdtype == CMDFUNCTION) {
678 				*pp = cmdp->next;
679 				freefunc(cmdp->param.func);
680 				ckfree(cmdp);
681 			} else {
682 				pp = &cmdp->next;
683 			}
684 		}
685 	}
686 	INTON;
687 }
688 
689 
690 
691 /*
692  * Locate a command in the command hash table.  If "add" is nonzero,
693  * add the command to the table if it is not already present.  The
694  * variable "lastcmdentry" is set to point to the address of the link
695  * pointing to the entry, so that delete_cmd_entry can delete the
696  * entry.
697  */
698 
699 struct tblentry **lastcmdentry;
700 
701 
702 STATIC struct tblentry *
703 cmdlookup(char *name, int add)
704 {
705 	int hashval;
706 	char *p;
707 	struct tblentry *cmdp;
708 	struct tblentry **pp;
709 
710 	p = name;
711 	hashval = *p << 4;
712 	while (*p)
713 		hashval += *p++;
714 	hashval &= 0x7FFF;
715 	pp = &cmdtable[hashval % CMDTABLESIZE];
716 	for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
717 		if (equal(cmdp->cmdname, name))
718 			break;
719 		pp = &cmdp->next;
720 	}
721 	if (add && cmdp == NULL) {
722 		INTOFF;
723 		cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
724 					+ strlen(name) + 1);
725 		cmdp->next = NULL;
726 		cmdp->cmdtype = CMDUNKNOWN;
727 		cmdp->rehash = 0;
728 		strcpy(cmdp->cmdname, name);
729 		INTON;
730 	}
731 	lastcmdentry = pp;
732 	return cmdp;
733 }
734 
735 /*
736  * Delete the command entry returned on the last lookup.
737  */
738 
739 STATIC void
740 delete_cmd_entry(void)
741 {
742 	struct tblentry *cmdp;
743 
744 	INTOFF;
745 	cmdp = *lastcmdentry;
746 	*lastcmdentry = cmdp->next;
747 	ckfree(cmdp);
748 	INTON;
749 }
750 
751 
752 
753 /*
754  * Add a new command entry, replacing any existing command entry for
755  * the same name.
756  */
757 
758 void
759 addcmdentry(char *name, struct cmdentry *entry)
760 {
761 	struct tblentry *cmdp;
762 
763 	INTOFF;
764 	cmdp = cmdlookup(name, 1);
765 	if (cmdp->cmdtype == CMDFUNCTION) {
766 		freefunc(cmdp->param.func);
767 	}
768 	cmdp->cmdtype = entry->cmdtype;
769 	cmdp->param = entry->u;
770 	INTON;
771 }
772 
773 
774 /*
775  * Define a shell function.
776  */
777 
778 void
779 defun(char *name, union node *func)
780 {
781 	struct cmdentry entry;
782 
783 	INTOFF;
784 	entry.cmdtype = CMDFUNCTION;
785 	entry.u.func = copyfunc(func);
786 	addcmdentry(name, &entry);
787 	INTON;
788 }
789 
790 
791 /*
792  * Delete a function if it exists.
793  */
794 
795 int
796 unsetfunc(char *name)
797 {
798 	struct tblentry *cmdp;
799 
800 	if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
801 		freefunc(cmdp->param.func);
802 		delete_cmd_entry();
803 		return (0);
804 	}
805 	return (1);
806 }
807 
808 /*
809  * Locate and print what a word is...
810  */
811 
812 int
813 typecmd(int argc, char **argv)
814 {
815 	struct cmdentry entry;
816 	struct tblentry *cmdp;
817 	char **pp;
818 	struct alias *ap;
819 	int i;
820 	int error = 0;
821 	extern char *const parsekwd[];
822 
823 	for (i = 1; i < argc; i++) {
824 		out1str(argv[i]);
825 		/* First look at the keywords */
826 		for (pp = (char **)parsekwd; *pp; pp++)
827 			if (**pp == *argv[i] && equal(*pp, argv[i]))
828 				break;
829 
830 		if (*pp) {
831 			out1str(" is a shell keyword\n");
832 			continue;
833 		}
834 
835 		/* Then look at the aliases */
836 		if ((ap = lookupalias(argv[i], 1)) != NULL) {
837 			out1fmt(" is an alias for %s\n", ap->val);
838 			continue;
839 		}
840 
841 		/* Then check if it is a tracked alias */
842 		if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
843 			entry.cmdtype = cmdp->cmdtype;
844 			entry.u = cmdp->param;
845 		}
846 		else {
847 			/* Finally use brute force */
848 			find_command(argv[i], &entry, 0, pathval());
849 		}
850 
851 		switch (entry.cmdtype) {
852 		case CMDNORMAL: {
853 			if (strchr(argv[i], '/') == NULL) {
854 				char *path = pathval(), *name;
855 				int j = entry.u.index;
856 				do {
857 					name = padvance(&path, argv[i]);
858 					stunalloc(name);
859 				} while (--j >= 0);
860 				out1fmt(" is%s %s\n",
861 				    cmdp ? " a tracked alias for" : "", name);
862 			} else {
863 				if (access(argv[i], X_OK) == 0)
864 					out1fmt(" is %s\n", argv[i]);
865 				else
866 					out1fmt(": %s\n", strerror(errno));
867 			}
868 			break;
869 		}
870 		case CMDFUNCTION:
871 			out1str(" is a shell function\n");
872 			break;
873 
874 		case CMDBUILTIN:
875 			out1str(" is a shell builtin\n");
876 			break;
877 
878 		default:
879 			out1str(": not found\n");
880 			error |= 127;
881 			break;
882 		}
883 	}
884 	return error;
885 }
886