1/*	$NetBSD: exec.c,v 1.41 2008/02/15 17:26:06 matt Exp $	*/
2
3/*-
4 * Copyright (c) 1991, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36#ifndef lint
37#if 0
38static char sccsid[] = "@(#)exec.c	8.4 (Berkeley) 6/8/95";
39#else
40__RCSID("$NetBSD: exec.c,v 1.41 2008/02/15 17:26:06 matt Exp $");
41#endif
42#endif /* not lint */
43
44#include <sys/types.h>
45#include <sys/stat.h>
46#include <sys/wait.h>
47#include <unistd.h>
48#include <fcntl.h>
49#include <errno.h>
50#include <stdio.h>
51#include <stdlib.h>
52
53/*
54 * When commands are first encountered, they are entered in a hash table.
55 * This ensures that a full path search will not have to be done for them
56 * on each invocation.
57 *
58 * We should investigate converting to a linear search, even though that
59 * would make the command name "hash" a misnomer.
60 */
61
62#include "shell.h"
63#include "main.h"
64#include "nodes.h"
65#include "parser.h"
66#include "redir.h"
67#include "eval.h"
68#include "exec.h"
69#include "builtins.h"
70#include "var.h"
71#include "options.h"
72#include "input.h"
73#include "output.h"
74#include "syntax.h"
75#include "memalloc.h"
76#include "error.h"
77#include "init.h"
78#include "mystring.h"
79#include "show.h"
80#include "jobs.h"
81#include "alias.h"
82
83
84#define CMDTABLESIZE 31		/* should be prime */
85#define ARB 1			/* actual size determined at run time */
86
87
88
89struct tblentry {
90	struct tblentry *next;	/* next entry in hash chain */
91	union param param;	/* definition of builtin function */
92	short cmdtype;		/* index identifying command */
93	char rehash;		/* if set, cd done since entry created */
94	char cmdname[ARB];	/* name of command */
95};
96
97
98STATIC struct tblentry *cmdtable[CMDTABLESIZE];
99STATIC int builtinloc = -1;		/* index in path of %builtin, or -1 */
100int exerrno = 0;			/* Last exec error */
101
102
103STATIC void tryexec(char *, char **, char **, int);
104STATIC void printentry(struct tblentry *, int);
105STATIC void clearcmdentry(int);
106STATIC struct tblentry *cmdlookup(const char *, int);
107STATIC void delete_cmd_entry(void);
108
109#ifndef BSD
110STATIC void execinterp(char **, char **);
111#endif
112
113
114extern const char *const parsekwd[];
115
116/*
117 * Exec a program.  Never returns.  If you change this routine, you may
118 * have to change the find_command routine as well.
119 */
120
121void
122shellexec(char **argv, char **envp, const char *path, int idx, int vforked)
123{
124	char *cmdname;
125	int e;
126
127	if (strchr(argv[0], '/') != NULL) {
128		tryexec(argv[0], argv, envp, vforked);
129		e = errno;
130	} else {
131		e = ENOENT;
132		while ((cmdname = padvance(&path, argv[0])) != NULL) {
133			if (--idx < 0 && pathopt == NULL) {
134				tryexec(cmdname, argv, envp, vforked);
135				if (errno != ENOENT && errno != ENOTDIR)
136					e = errno;
137			}
138			stunalloc(cmdname);
139		}
140	}
141
142	/* Map to POSIX errors */
143	switch (e) {
144	case EACCES:
145		exerrno = 126;
146		break;
147	case ENOENT:
148		exerrno = 127;
149		break;
150	default:
151		exerrno = 2;
152		break;
153	}
154	TRACE(("shellexec failed for %s, errno %d, vforked %d, suppressint %d\n",
155		argv[0], e, vforked, suppressint ));
156	exerror(EXEXEC, "%s: %s", argv[0], errmsg(e, E_EXEC));
157	/* NOTREACHED */
158}
159
160
161STATIC void
162tryexec(char *cmd, char **argv, char **envp, int vforked)
163{
164	int e;
165#ifndef BSD
166	char *p;
167#endif
168
169#ifdef SYSV
170	do {
171		execve(cmd, argv, envp);
172	} while (errno == EINTR);
173#else
174	execve(cmd, argv, envp);
175#endif
176	e = errno;
177	if (e == ENOEXEC) {
178		if (vforked) {
179			/* We are currently vfork(2)ed, so raise an
180			 * exception, and evalcommand will try again
181			 * with a normal fork(2).
182			 */
183			exraise(EXSHELLPROC);
184		}
185#ifdef DEBUG
186		TRACE(("execve(cmd=%s) returned ENOEXEC\n", cmd));
187#endif
188		initshellproc();
189		setinputfile(cmd, 0);
190		commandname = arg0 = savestr(argv[0]);
191#ifndef BSD
192		pgetc(); pungetc();		/* fill up input buffer */
193		p = parsenextc;
194		if (parsenleft > 2 && p[0] == '#' && p[1] == '!') {
195			argv[0] = cmd;
196			execinterp(argv, envp);
197		}
198#endif
199		setparam(argv + 1);
200		exraise(EXSHELLPROC);
201	}
202	errno = e;
203}
204
205
206#ifndef BSD
207/*
208 * Execute an interpreter introduced by "#!", for systems where this
209 * feature has not been built into the kernel.  If the interpreter is
210 * the shell, return (effectively ignoring the "#!").  If the execution
211 * of the interpreter fails, exit.
212 *
213 * This code peeks inside the input buffer in order to avoid actually
214 * reading any input.  It would benefit from a rewrite.
215 */
216
217#define NEWARGS 5
218
219STATIC void
220execinterp(char **argv, char **envp)
221{
222	int n;
223	char *inp;
224	char *outp;
225	char c;
226	char *p;
227	char **ap;
228	char *newargs[NEWARGS];
229	int i;
230	char **ap2;
231	char **new;
232
233	n = parsenleft - 2;
234	inp = parsenextc + 2;
235	ap = newargs;
236	for (;;) {
237		while (--n >= 0 && (*inp == ' ' || *inp == '\t'))
238			inp++;
239		if (n < 0)
240			goto bad;
241		if ((c = *inp++) == '\n')
242			break;
243		if (ap == &newargs[NEWARGS])
244bad:		  error("Bad #! line");
245		STARTSTACKSTR(outp);
246		do {
247			STPUTC(c, outp);
248		} while (--n >= 0 && (c = *inp++) != ' ' && c != '\t' && c != '\n');
249		STPUTC('\0', outp);
250		n++, inp--;
251		*ap++ = grabstackstr(outp);
252	}
253	if (ap == newargs + 1) {	/* if no args, maybe no exec is needed */
254		p = newargs[0];
255		for (;;) {
256			if (equal(p, "sh") || equal(p, "ash")) {
257				return;
258			}
259			while (*p != '/') {
260				if (*p == '\0')
261					goto break2;
262				p++;
263			}
264			p++;
265		}
266break2:;
267	}
268	i = (char *)ap - (char *)newargs;		/* size in bytes */
269	if (i == 0)
270		error("Bad #! line");
271	for (ap2 = argv ; *ap2++ != NULL ; );
272	new = ckmalloc(i + ((char *)ap2 - (char *)argv));
273	ap = newargs, ap2 = new;
274	while ((i -= sizeof (char **)) >= 0)
275		*ap2++ = *ap++;
276	ap = argv;
277	while (*ap2++ = *ap++);
278	shellexec(new, envp, pathval(), 0);
279	/* NOTREACHED */
280}
281#endif
282
283
284
285/*
286 * Do a path search.  The variable path (passed by reference) should be
287 * set to the start of the path before the first call; padvance will update
288 * this value as it proceeds.  Successive calls to padvance will return
289 * the possible path expansions in sequence.  If an option (indicated by
290 * a percent sign) appears in the path entry then the global variable
291 * pathopt will be set to point to it; otherwise pathopt will be set to
292 * NULL.
293 */
294
295const char *pathopt;
296
297char *
298padvance(const char **path, const char *name)
299{
300	const char *p;
301	char *q;
302	const char *start;
303	int len;
304
305	if (*path == NULL)
306		return NULL;
307	start = *path;
308	for (p = start ; *p && *p != ':' && *p != '%' ; p++);
309	len = p - start + strlen(name) + 2;	/* "2" is for '/' and '\0' */
310	while (stackblocksize() < len)
311		growstackblock();
312	q = stackblock();
313	if (p != start) {
314		memcpy(q, start, p - start);
315		q += p - start;
316		*q++ = '/';
317	}
318	strcpy(q, name);
319	pathopt = NULL;
320	if (*p == '%') {
321		pathopt = ++p;
322		while (*p && *p != ':')  p++;
323	}
324	if (*p == ':')
325		*path = p + 1;
326	else
327		*path = NULL;
328	return stalloc(len);
329}
330
331
332
333/*** Command hashing code ***/
334
335
336int
337hashcmd(int argc, char **argv)
338{
339	struct tblentry **pp;
340	struct tblentry *cmdp;
341	int c;
342	int verbose;
343	struct cmdentry entry;
344	char *name;
345
346	verbose = 0;
347	while ((c = nextopt("rv")) != '\0') {
348		if (c == 'r') {
349			clearcmdentry(0);
350		} else if (c == 'v') {
351			verbose++;
352		}
353	}
354	if (*argptr == NULL) {
355		for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
356			for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
357				if (verbose || cmdp->cmdtype == CMDNORMAL)
358					printentry(cmdp, verbose);
359			}
360		}
361		return 0;
362	}
363	while ((name = *argptr) != NULL) {
364		if ((cmdp = cmdlookup(name, 0)) != NULL
365		 && (cmdp->cmdtype == CMDNORMAL
366		     || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)))
367			delete_cmd_entry();
368		find_command(name, &entry, DO_ERR, pathval());
369		if (verbose) {
370			if (entry.cmdtype != CMDUNKNOWN) {	/* if no error msg */
371				cmdp = cmdlookup(name, 0);
372				if (cmdp != NULL)
373					printentry(cmdp, verbose);
374			}
375			flushall();
376		}
377		argptr++;
378	}
379	return 0;
380}
381
382
383STATIC void
384printentry(struct tblentry *cmdp, int verbose)
385{
386	int idx;
387	const char *path;
388	char *name;
389
390	switch (cmdp->cmdtype) {
391	case CMDNORMAL:
392		idx = cmdp->param.index;
393		path = pathval();
394		do {
395			name = padvance(&path, cmdp->cmdname);
396			stunalloc(name);
397		} while (--idx >= 0);
398		out1str(name);
399		break;
400	case CMDSPLBLTIN:
401		out1fmt("special builtin %s", cmdp->cmdname);
402		break;
403	case CMDBUILTIN:
404		out1fmt("builtin %s", cmdp->cmdname);
405		break;
406	case CMDFUNCTION:
407		out1fmt("function %s", cmdp->cmdname);
408		if (verbose) {
409			struct procstat ps;
410			INTOFF;
411			commandtext(&ps, cmdp->param.func);
412			INTON;
413			out1str("() { ");
414			out1str(ps.cmd);
415			out1str("; }");
416		}
417		break;
418	default:
419		error("internal error: %s cmdtype %d", cmdp->cmdname, cmdp->cmdtype);
420	}
421	if (cmdp->rehash)
422		out1c('*');
423	out1c('\n');
424}
425
426
427
428/*
429 * Resolve a command name.  If you change this routine, you may have to
430 * change the shellexec routine as well.
431 */
432
433void
434find_command(char *name, struct cmdentry *entry, int act, const char *path)
435{
436	struct tblentry *cmdp, loc_cmd;
437	int idx;
438	int prev;
439	char *fullname;
440	struct stat statb;
441	int e;
442	int (*bltin)(int,char **);
443
444	/* If name contains a slash, don't use PATH or hash table */
445	if (strchr(name, '/') != NULL) {
446		if (act & DO_ABS) {
447			while (stat(name, &statb) < 0) {
448#ifdef SYSV
449				if (errno == EINTR)
450					continue;
451#endif
452				if (errno != ENOENT && errno != ENOTDIR)
453					e = errno;
454				entry->cmdtype = CMDUNKNOWN;
455				entry->u.index = -1;
456				return;
457			}
458			entry->cmdtype = CMDNORMAL;
459			entry->u.index = -1;
460			return;
461		}
462		entry->cmdtype = CMDNORMAL;
463		entry->u.index = 0;
464		return;
465	}
466
467	if (path != pathval())
468		act |= DO_ALTPATH;
469
470	if (act & DO_ALTPATH && strstr(path, "%builtin") != NULL)
471		act |= DO_ALTBLTIN;
472
473	/* If name is in the table, check answer will be ok */
474	if ((cmdp = cmdlookup(name, 0)) != NULL) {
475		do {
476			switch (cmdp->cmdtype) {
477			case CMDNORMAL:
478				if (act & DO_ALTPATH) {
479					cmdp = NULL;
480					continue;
481				}
482				break;
483			case CMDFUNCTION:
484				if (act & DO_NOFUNC) {
485					cmdp = NULL;
486					continue;
487				}
488				break;
489			case CMDBUILTIN:
490				if ((act & DO_ALTBLTIN) || builtinloc >= 0) {
491					cmdp = NULL;
492					continue;
493				}
494				break;
495			}
496			/* if not invalidated by cd, we're done */
497			if (cmdp->rehash == 0)
498				goto success;
499		} while (0);
500	}
501
502	/* If %builtin not in path, check for builtin next */
503	if ((act & DO_ALTPATH ? !(act & DO_ALTBLTIN) : builtinloc < 0) &&
504	    (bltin = find_builtin(name)) != 0)
505		goto builtin_success;
506
507	/* We have to search path. */
508	prev = -1;		/* where to start */
509	if (cmdp) {		/* doing a rehash */
510		if (cmdp->cmdtype == CMDBUILTIN)
511			prev = builtinloc;
512		else
513			prev = cmdp->param.index;
514	}
515
516	e = ENOENT;
517	idx = -1;
518loop:
519	while ((fullname = padvance(&path, name)) != NULL) {
520		stunalloc(fullname);
521		idx++;
522		if (pathopt) {
523			if (prefix("builtin", pathopt)) {
524				if ((bltin = find_builtin(name)) == 0)
525					goto loop;
526				goto builtin_success;
527			} else if (prefix("func", pathopt)) {
528				/* handled below */
529			} else {
530				/* ignore unimplemented options */
531				goto loop;
532			}
533		}
534		/* if rehash, don't redo absolute path names */
535		if (fullname[0] == '/' && idx <= prev) {
536			if (idx < prev)
537				goto loop;
538			TRACE(("searchexec \"%s\": no change\n", name));
539			goto success;
540		}
541		while (stat(fullname, &statb) < 0) {
542#ifdef SYSV
543			if (errno == EINTR)
544				continue;
545#endif
546			if (errno != ENOENT && errno != ENOTDIR)
547				e = errno;
548			goto loop;
549		}
550		e = EACCES;	/* if we fail, this will be the error */
551		if (!S_ISREG(statb.st_mode))
552			goto loop;
553		if (pathopt) {		/* this is a %func directory */
554			if (act & DO_NOFUNC)
555				goto loop;
556			stalloc(strlen(fullname) + 1);
557			readcmdfile(fullname);
558			if ((cmdp = cmdlookup(name, 0)) == NULL ||
559			    cmdp->cmdtype != CMDFUNCTION)
560				error("%s not defined in %s", name, fullname);
561			stunalloc(fullname);
562			goto success;
563		}
564#ifdef notdef
565		/* XXX this code stops root executing stuff, and is buggy
566		   if you need a group from the group list. */
567		if (statb.st_uid == geteuid()) {
568			if ((statb.st_mode & 0100) == 0)
569				goto loop;
570		} else if (statb.st_gid == getegid()) {
571			if ((statb.st_mode & 010) == 0)
572				goto loop;
573		} else {
574			if ((statb.st_mode & 01) == 0)
575				goto loop;
576		}
577#endif
578		TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
579		INTOFF;
580		if (act & DO_ALTPATH) {
581			stalloc(strlen(fullname) + 1);
582			cmdp = &loc_cmd;
583		} else
584			cmdp = cmdlookup(name, 1);
585		cmdp->cmdtype = CMDNORMAL;
586		cmdp->param.index = idx;
587		INTON;
588		goto success;
589	}
590
591	/* We failed.  If there was an entry for this command, delete it */
592	if (cmdp)
593		delete_cmd_entry();
594	if (act & DO_ERR)
595		outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC));
596	entry->cmdtype = CMDUNKNOWN;
597	return;
598
599builtin_success:
600	INTOFF;
601	if (act & DO_ALTPATH)
602		cmdp = &loc_cmd;
603	else
604		cmdp = cmdlookup(name, 1);
605	if (cmdp->cmdtype == CMDFUNCTION)
606		/* DO_NOFUNC must have been set */
607		cmdp = &loc_cmd;
608	cmdp->cmdtype = CMDBUILTIN;
609	cmdp->param.bltin = bltin;
610	INTON;
611success:
612	if (cmdp) {
613		cmdp->rehash = 0;
614		entry->cmdtype = cmdp->cmdtype;
615		entry->u = cmdp->param;
616	} else
617		entry->cmdtype = CMDUNKNOWN;
618}
619
620
621
622/*
623 * Search the table of builtin commands.
624 */
625
626int
627(*find_builtin(name))(int, char **)
628	char *name;
629{
630	const struct builtincmd *bp;
631
632	for (bp = builtincmd ; bp->name ; bp++) {
633		if (*bp->name == *name && equal(bp->name, name))
634			return bp->builtin;
635	}
636	return 0;
637}
638
639int
640(*find_splbltin(name))(int, char **)
641	char *name;
642{
643	const struct builtincmd *bp;
644
645	for (bp = splbltincmd ; bp->name ; bp++) {
646		if (*bp->name == *name && equal(bp->name, name))
647			return bp->builtin;
648	}
649	return 0;
650}
651
652/*
653 * At shell startup put special builtins into hash table.
654 * ensures they are executed first (see posix).
655 * We stop functions being added with the same name
656 * (as they are impossible to call)
657 */
658
659void
660hash_special_builtins(void)
661{
662	const struct builtincmd *bp;
663	struct tblentry *cmdp;
664
665	for (bp = splbltincmd ; bp->name ; bp++) {
666		cmdp = cmdlookup(bp->name, 1);
667		cmdp->cmdtype = CMDSPLBLTIN;
668		cmdp->param.bltin = bp->builtin;
669	}
670}
671
672
673
674/*
675 * Called when a cd is done.  Marks all commands so the next time they
676 * are executed they will be rehashed.
677 */
678
679void
680hashcd(void)
681{
682	struct tblentry **pp;
683	struct tblentry *cmdp;
684
685	for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
686		for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
687			if (cmdp->cmdtype == CMDNORMAL
688			 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
689				cmdp->rehash = 1;
690		}
691	}
692}
693
694
695
696/*
697 * Fix command hash table when PATH changed.
698 * Called before PATH is changed.  The argument is the new value of PATH;
699 * pathval() still returns the old value at this point.
700 * Called with interrupts off.
701 */
702
703void
704changepath(const char *newval)
705{
706	const char *old, *new;
707	int idx;
708	int firstchange;
709	int bltin;
710
711	old = pathval();
712	new = newval;
713	firstchange = 9999;	/* assume no change */
714	idx = 0;
715	bltin = -1;
716	for (;;) {
717		if (*old != *new) {
718			firstchange = idx;
719			if ((*old == '\0' && *new == ':')
720			 || (*old == ':' && *new == '\0'))
721				firstchange++;
722			old = new;	/* ignore subsequent differences */
723		}
724		if (*new == '\0')
725			break;
726		if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
727			bltin = idx;
728		if (*new == ':') {
729			idx++;
730		}
731		new++, old++;
732	}
733	if (builtinloc < 0 && bltin >= 0)
734		builtinloc = bltin;		/* zap builtins */
735	if (builtinloc >= 0 && bltin < 0)
736		firstchange = 0;
737	clearcmdentry(firstchange);
738	builtinloc = bltin;
739}
740
741
742/*
743 * Clear out command entries.  The argument specifies the first entry in
744 * PATH which has changed.
745 */
746
747STATIC void
748clearcmdentry(int firstchange)
749{
750	struct tblentry **tblp;
751	struct tblentry **pp;
752	struct tblentry *cmdp;
753
754	INTOFF;
755	for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
756		pp = tblp;
757		while ((cmdp = *pp) != NULL) {
758			if ((cmdp->cmdtype == CMDNORMAL &&
759			     cmdp->param.index >= firstchange)
760			 || (cmdp->cmdtype == CMDBUILTIN &&
761			     builtinloc >= firstchange)) {
762				*pp = cmdp->next;
763				ckfree(cmdp);
764			} else {
765				pp = &cmdp->next;
766			}
767		}
768	}
769	INTON;
770}
771
772
773/*
774 * Delete all functions.
775 */
776
777#ifdef mkinit
778MKINIT void deletefuncs(void);
779MKINIT void hash_special_builtins(void);
780
781INIT {
782	hash_special_builtins();
783}
784
785SHELLPROC {
786	deletefuncs();
787}
788#endif
789
790void
791deletefuncs(void)
792{
793	struct tblentry **tblp;
794	struct tblentry **pp;
795	struct tblentry *cmdp;
796
797	INTOFF;
798	for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
799		pp = tblp;
800		while ((cmdp = *pp) != NULL) {
801			if (cmdp->cmdtype == CMDFUNCTION) {
802				*pp = cmdp->next;
803				freefunc(cmdp->param.func);
804				ckfree(cmdp);
805			} else {
806				pp = &cmdp->next;
807			}
808		}
809	}
810	INTON;
811}
812
813
814
815/*
816 * Locate a command in the command hash table.  If "add" is nonzero,
817 * add the command to the table if it is not already present.  The
818 * variable "lastcmdentry" is set to point to the address of the link
819 * pointing to the entry, so that delete_cmd_entry can delete the
820 * entry.
821 */
822
823struct tblentry **lastcmdentry;
824
825
826STATIC struct tblentry *
827cmdlookup(const char *name, int add)
828{
829	int hashval;
830	const char *p;
831	struct tblentry *cmdp;
832	struct tblentry **pp;
833
834	p = name;
835	hashval = *p << 4;
836	while (*p)
837		hashval += *p++;
838	hashval &= 0x7FFF;
839	pp = &cmdtable[hashval % CMDTABLESIZE];
840	for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
841		if (equal(cmdp->cmdname, name))
842			break;
843		pp = &cmdp->next;
844	}
845	if (add && cmdp == NULL) {
846		INTOFF;
847		cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
848					+ strlen(name) + 1);
849		cmdp->next = NULL;
850		cmdp->cmdtype = CMDUNKNOWN;
851		cmdp->rehash = 0;
852		strcpy(cmdp->cmdname, name);
853		INTON;
854	}
855	lastcmdentry = pp;
856	return cmdp;
857}
858
859/*
860 * Delete the command entry returned on the last lookup.
861 */
862
863STATIC void
864delete_cmd_entry(void)
865{
866	struct tblentry *cmdp;
867
868	INTOFF;
869	cmdp = *lastcmdentry;
870	*lastcmdentry = cmdp->next;
871	ckfree(cmdp);
872	INTON;
873}
874
875
876
877#ifdef notdef
878void
879getcmdentry(char *name, struct cmdentry *entry)
880{
881	struct tblentry *cmdp = cmdlookup(name, 0);
882
883	if (cmdp) {
884		entry->u = cmdp->param;
885		entry->cmdtype = cmdp->cmdtype;
886	} else {
887		entry->cmdtype = CMDUNKNOWN;
888		entry->u.index = 0;
889	}
890}
891#endif
892
893
894/*
895 * Add a new command entry, replacing any existing command entry for
896 * the same name - except special builtins.
897 */
898
899STATIC void
900addcmdentry(char *name, struct cmdentry *entry)
901{
902	struct tblentry *cmdp;
903
904	INTOFF;
905	cmdp = cmdlookup(name, 1);
906	if (cmdp->cmdtype != CMDSPLBLTIN) {
907		if (cmdp->cmdtype == CMDFUNCTION) {
908			freefunc(cmdp->param.func);
909		}
910		cmdp->cmdtype = entry->cmdtype;
911		cmdp->param = entry->u;
912	}
913	INTON;
914}
915
916
917/*
918 * Define a shell function.
919 */
920
921void
922defun(char *name, union node *func)
923{
924	struct cmdentry entry;
925
926	INTOFF;
927	entry.cmdtype = CMDFUNCTION;
928	entry.u.func = copyfunc(func);
929	addcmdentry(name, &entry);
930	INTON;
931}
932
933
934/*
935 * Delete a function if it exists.
936 */
937
938int
939unsetfunc(char *name)
940{
941	struct tblentry *cmdp;
942
943	if ((cmdp = cmdlookup(name, 0)) != NULL &&
944	    cmdp->cmdtype == CMDFUNCTION) {
945		freefunc(cmdp->param.func);
946		delete_cmd_entry();
947		return (0);
948	}
949	return (1);
950}
951
952/*
953 * Locate and print what a word is...
954 * also used for 'command -[v|V]'
955 */
956
957int
958typecmd(int argc, char **argv)
959{
960	struct cmdentry entry;
961	struct tblentry *cmdp;
962	const char * const *pp;
963	struct alias *ap;
964	int err = 0;
965	char *arg;
966	int c;
967	int V_flag = 0;
968	int v_flag = 0;
969	int p_flag = 0;
970
971	while ((c = nextopt("vVp")) != 0) {
972		switch (c) {
973		case 'v': v_flag = 1; break;
974		case 'V': V_flag = 1; break;
975		case 'p': p_flag = 1; break;
976		}
977	}
978
979	if (p_flag && (v_flag || V_flag))
980		error("cannot specify -p with -v or -V");
981
982	while ((arg = *argptr++)) {
983		if (!v_flag)
984			out1str(arg);
985		/* First look at the keywords */
986		for (pp = parsekwd; *pp; pp++)
987			if (**pp == *arg && equal(*pp, arg))
988				break;
989
990		if (*pp) {
991			if (v_flag)
992				err = 1;
993			else
994				out1str(" is a shell keyword\n");
995			continue;
996		}
997
998		/* Then look at the aliases */
999		if ((ap = lookupalias(arg, 1)) != NULL) {
1000			if (!v_flag)
1001				out1fmt(" is an alias for \n");
1002			out1fmt("%s\n", ap->val);
1003			continue;
1004		}
1005
1006		/* Then check if it is a tracked alias */
1007		if ((cmdp = cmdlookup(arg, 0)) != NULL) {
1008			entry.cmdtype = cmdp->cmdtype;
1009			entry.u = cmdp->param;
1010		} else {
1011			/* Finally use brute force */
1012			find_command(arg, &entry, DO_ABS, pathval());
1013		}
1014
1015		switch (entry.cmdtype) {
1016		case CMDNORMAL: {
1017			if (strchr(arg, '/') == NULL) {
1018				const char *path = pathval();
1019				char *name;
1020				int j = entry.u.index;
1021				do {
1022					name = padvance(&path, arg);
1023					stunalloc(name);
1024				} while (--j >= 0);
1025				if (!v_flag)
1026					out1fmt(" is%s ",
1027					    cmdp ? " a tracked alias for" : "");
1028				out1fmt("%s\n", name);
1029			} else {
1030				if (access(arg, X_OK) == 0) {
1031					if (!v_flag)
1032						out1fmt(" is ");
1033					out1fmt("%s\n", arg);
1034				} else {
1035					if (!v_flag)
1036						out1fmt(": %s\n",
1037						    strerror(errno));
1038					else
1039						err = 126;
1040				}
1041			}
1042 			break;
1043		}
1044		case CMDFUNCTION:
1045			if (!v_flag)
1046				out1str(" is a shell function\n");
1047			else
1048				out1fmt("%s\n", arg);
1049			break;
1050
1051		case CMDBUILTIN:
1052			if (!v_flag)
1053				out1str(" is a shell builtin\n");
1054			else
1055				out1fmt("%s\n", arg);
1056			break;
1057
1058		case CMDSPLBLTIN:
1059			if (!v_flag)
1060				out1str(" is a special shell builtin\n");
1061			else
1062				out1fmt("%s\n", arg);
1063			break;
1064
1065		default:
1066			if (!v_flag)
1067				out1str(": not found\n");
1068			err = 127;
1069			break;
1070		}
1071	}
1072	return err;
1073}
1074