xref: /freebsd/contrib/tcsh/sh.exec.c (revision c98323078dede7579020518ec84cdcb478e5c142)
1 /* $Header: /src/pub/tcsh/sh.exec.c,v 3.58 2003/03/12 19:14:51 christos Exp $ */
2 /*
3  * sh.exec.c: Search, find, and execute a command!
4  */
5 /*-
6  * Copyright (c) 1980, 1991 The Regents of the University of California.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 #include "sh.h"
34 
35 RCSID("$Id: sh.exec.c,v 3.58 2003/03/12 19:14:51 christos Exp $")
36 
37 #include "tc.h"
38 #include "tw.h"
39 #ifdef WINNT_NATIVE
40 #include <nt.const.h>
41 #endif /*WINNT_NATIVE*/
42 
43 /*
44  * C shell
45  */
46 
47 #ifndef OLDHASH
48 # define FASTHASH	/* Fast hashing is the default */
49 #endif /* OLDHASH */
50 
51 /*
52  * System level search and execute of a command.
53  * We look in each directory for the specified command name.
54  * If the name contains a '/' then we execute only the full path name.
55  * If there is no search path then we execute only full path names.
56  */
57 
58 /*
59  * As we search for the command we note the first non-trivial error
60  * message for presentation to the user.  This allows us often
61  * to show that a file has the wrong mode/no access when the file
62  * is not in the last component of the search path, so we must
63  * go on after first detecting the error.
64  */
65 static char *exerr;		/* Execution error message */
66 static Char *expath;		/* Path for exerr */
67 
68 /*
69  * The two part hash function is designed to let texec() call the
70  * more expensive hashname() only once and the simple hash() several
71  * times (once for each path component checked).
72  * Byte size is assumed to be 8.
73  */
74 #define BITS_PER_BYTE	8
75 
76 #ifdef FASTHASH
77 /*
78  * xhash is an array of hash buckets which are used to hash execs.  If
79  * it is allocated (havhash true), then to tell if ``name'' is
80  * (possibly) presend in the i'th component of the variable path, look
81  * at the [hashname(name)] bucket of size [hashwidth] bytes, in the [i
82  * mod size*8]'th bit.  The cache size is defaults to a length of 1024
83  * buckets, each 1 byte wide.  This implementation guarantees that
84  * objects n bytes wide will be aligned on n byte boundaries.
85  */
86 # define HSHMUL		241
87 
88 static unsigned long *xhash = NULL;
89 static unsigned int hashlength = 0, uhashlength = 0;
90 static unsigned int hashwidth = 0, uhashwidth = 0;
91 static int hashdebug = 0;
92 
93 # define hash(a, b)	(((a) * HSHMUL + (b)) % (hashlength))
94 # define widthof(t)	(sizeof(t) * BITS_PER_BYTE)
95 # define tbit(f, i, t)	(((t *) xhash)[(f)] &  \
96 			 (1L << (i & (widthof(t) - 1))))
97 # define tbis(f, i, t)	(((t *) xhash)[(f)] |= \
98 			 (1L << (i & (widthof(t) - 1))))
99 # define cbit(f, i)	tbit(f, i, unsigned char)
100 # define cbis(f, i)	tbis(f, i, unsigned char)
101 # define sbit(f, i)	tbit(f, i, unsigned short)
102 # define sbis(f, i)	tbis(f, i, unsigned short)
103 # define ibit(f, i)	tbit(f, i, unsigned int)
104 # define ibis(f, i)	tbis(f, i, unsigned int)
105 # define lbit(f, i)	tbit(f, i, unsigned long)
106 # define lbis(f, i)	tbis(f, i, unsigned long)
107 
108 # define bit(f, i) (hashwidth==sizeof(unsigned char)  ? cbit(f,i) : \
109  		    ((hashwidth==sizeof(unsigned short) ? sbit(f,i) : \
110 		     ((hashwidth==sizeof(unsigned int)   ? ibit(f,i) : \
111 		     lbit(f,i))))))
112 # define bis(f, i) (hashwidth==sizeof(unsigned char)  ? cbis(f,i) : \
113  		    ((hashwidth==sizeof(unsigned short) ? sbis(f,i) : \
114 		     ((hashwidth==sizeof(unsigned int)   ? ibis(f,i) : \
115 		     lbis(f,i))))))
116 #else /* OLDHASH */
117 /*
118  * Xhash is an array of HSHSIZ bits (HSHSIZ / 8 chars), which are used
119  * to hash execs.  If it is allocated (havhash true), then to tell
120  * whether ``name'' is (possibly) present in the i'th component
121  * of the variable path, you look at the bit in xhash indexed by
122  * hash(hashname("name"), i).  This is setup automatically
123  * after .login is executed, and recomputed whenever ``path'' is
124  * changed.
125  */
126 # define HSHSIZ		8192	/* 1k bytes */
127 # define HSHMASK		(HSHSIZ - 1)
128 # define HSHMUL		243
129 static char xhash[HSHSIZ / BITS_PER_BYTE];
130 
131 # define hash(a, b)	(((a) * HSHMUL + (b)) & HSHMASK)
132 # define bit(h, b)	((h)[(b) >> 3] & 1 << ((b) & 7))	/* bit test */
133 # define bis(h, b)	((h)[(b) >> 3] |= 1 << ((b) & 7))	/* bit set */
134 
135 #endif /* FASTHASH */
136 
137 #ifdef VFORK
138 static int hits, misses;
139 #endif /* VFORK */
140 
141 /* Dummy search path for just absolute search when no path */
142 static Char *justabs[] = {STRNULL, 0};
143 
144 static	void	pexerr		__P((void));
145 static	void	texec		__P((Char *, Char **));
146 int	hashname	__P((Char *));
147 static	int 	iscommand	__P((Char *));
148 
149 void
150 doexec(t, do_glob)
151     register struct command *t;
152     bool do_glob;
153 {
154     Char *dp, **pv, **av, *sav;
155     struct varent *v;
156     bool slash;
157     int hashval, i;
158     Char   *blk[2];
159 
160     /*
161      * Glob the command name. We will search $path even if this does something,
162      * as in sh but not in csh.  One special case: if there is no PATH, then we
163      * execute only commands which start with '/'.
164      */
165     blk[0] = t->t_dcom[0];
166     blk[1] = 0;
167     gflag = 0;
168     if (do_glob)
169 	tglob(blk);
170     if (gflag) {
171 	pv = globall(blk);
172 	if (pv == 0) {
173 	    setname(short2str(blk[0]));
174 	    stderror(ERR_NAME | ERR_NOMATCH);
175 	}
176 	gargv = 0;
177     }
178     else
179 	pv = saveblk(blk);
180 
181     trim(pv);
182 
183     exerr = 0;
184     expath = Strsave(pv[0]);
185 #ifdef VFORK
186     Vexpath = expath;
187 #endif /* VFORK */
188 
189     v = adrof(STRpath);
190     if (v == 0 && expath[0] != '/' && expath[0] != '.') {
191 	blkfree(pv);
192 	pexerr();
193     }
194     slash = any(short2str(expath), '/');
195 
196     /*
197      * Glob the argument list, if necessary. Otherwise trim off the quote bits.
198      */
199     gflag = 0;
200     av = &t->t_dcom[1];
201     if (do_glob)
202 	tglob(av);
203     if (gflag) {
204 	av = globall(av);
205 	if (av == 0) {
206 	    blkfree(pv);
207 	    setname(short2str(expath));
208 	    stderror(ERR_NAME | ERR_NOMATCH);
209 	}
210 	gargv = 0;
211     }
212     else
213 	av = saveblk(av);
214 
215     blkfree(t->t_dcom);
216     t->t_dcom = blkspl(pv, av);
217     xfree((ptr_t) pv);
218     xfree((ptr_t) av);
219     av = t->t_dcom;
220     trim(av);
221 
222     if (*av == NULL || **av == '\0')
223 	pexerr();
224 
225     xechoit(av);		/* Echo command if -x */
226 #ifdef CLOSE_ON_EXEC
227     /*
228      * Since all internal file descriptors are set to close on exec, we don't
229      * need to close them explicitly here.  Just reorient ourselves for error
230      * messages.
231      */
232     SHIN = 0;
233     SHOUT = 1;
234     SHDIAG = 2;
235     OLDSTD = 0;
236     isoutatty = isatty(SHOUT);
237     isdiagatty = isatty(SHDIAG);
238 #else
239     closech();			/* Close random fd's */
240 #endif
241     /*
242      * We must do this AFTER any possible forking (like `foo` in glob) so that
243      * this shell can still do subprocesses.
244      */
245 #ifdef BSDSIGS
246     (void) sigsetmask((sigmask_t) 0);
247 #else /* BSDSIGS */
248     (void) sigrelse(SIGINT);
249     (void) sigrelse(SIGCHLD);
250 #endif /* BSDSIGS */
251 
252     /*
253      * If no path, no words in path, or a / in the filename then restrict the
254      * command search.
255      */
256     if (v == NULL || v->vec == NULL || v->vec[0] == NULL || slash)
257 	pv = justabs;
258     else
259 	pv = v->vec;
260     sav = Strspl(STRslash, *av);/* / command name for postpending */
261 #ifdef VFORK
262     Vsav = sav;
263 #endif /* VFORK */
264     hashval = havhash ? hashname(*av) : 0;
265 
266     i = 0;
267 #ifdef VFORK
268     hits++;
269 #endif /* VFORK */
270     do {
271 	/*
272 	 * Try to save time by looking at the hash table for where this command
273 	 * could be.  If we are doing delayed hashing, then we put the names in
274 	 * one at a time, as the user enters them.  This is kinda like Korn
275 	 * Shell's "tracked aliases".
276 	 */
277 	if (!slash && ABSOLUTEP(pv[0]) && havhash) {
278 #ifdef FASTHASH
279 	    if (!bit(hashval, i))
280 		goto cont;
281 #else /* OLDHASH */
282 	    int hashval1 = hash(hashval, i);
283 	    if (!bit(xhash, hashval1))
284 		goto cont;
285 #endif /* FASTHASH */
286 	}
287 	if (pv[0][0] == 0 || eq(pv[0], STRdot))	/* don't make ./xxx */
288 	{
289 
290 #ifdef COHERENT
291 	    if (t->t_dflg & F_AMPERSAND) {
292 # ifdef JOBDEBUG
293     	        xprintf("set SIGINT to SIG_IGN\n");
294     	        xprintf("set SIGQUIT to SIG_DFL\n");
295 # endif /* JOBDEBUG */
296     	        (void) signal(SIGINT,SIG_IGN); /* may not be necessary */
297 	        (void) signal(SIGQUIT,SIG_DFL);
298 	    }
299 
300 	    if (gointr && eq(gointr, STRminus)) {
301 # ifdef JOBDEBUG
302     	        xprintf("set SIGINT to SIG_IGN\n");
303     	        xprintf("set SIGQUIT to SIG_IGN\n");
304 # endif /* JOBDEBUG */
305     	        (void) signal(SIGINT,SIG_IGN); /* may not be necessary */
306 	        (void) signal(SIGQUIT,SIG_IGN);
307 	    }
308 #endif /* COHERENT */
309 
310 	    texec(*av, av);
311 }
312 	else {
313 	    dp = Strspl(*pv, sav);
314 #ifdef VFORK
315 	    Vdp = dp;
316 #endif /* VFORK */
317 
318 #ifdef COHERENT
319 	    if ((t->t_dflg & F_AMPERSAND)) {
320 # ifdef JOBDEBUG
321     	        xprintf("set SIGINT to SIG_IGN\n");
322 # endif /* JOBDEBUG */
323 		/*
324 		 * this is necessary on Coherent or all background
325 		 * jobs are killed by CTRL-C
326 		 * (there must be a better fix for this)
327 		 */
328     	        (void) signal(SIGINT,SIG_IGN);
329 	    }
330 	    if (gointr && eq(gointr,STRminus)) {
331 # ifdef JOBDEBUG
332     	        xprintf("set SIGINT to SIG_IGN\n");
333     	        xprintf("set SIGQUIT to SIG_IGN\n");
334 # endif /* JOBDEBUG */
335     	        (void) signal(SIGINT,SIG_IGN); /* may not be necessary */
336 	        (void) signal(SIGQUIT,SIG_IGN);
337 	    }
338 #endif /* COHERENT */
339 
340 	    texec(dp, av);
341 #ifdef VFORK
342 	    Vdp = 0;
343 #endif /* VFORK */
344 	    xfree((ptr_t) dp);
345 	}
346 #ifdef VFORK
347 	misses++;
348 #endif /* VFORK */
349 cont:
350 	pv++;
351 	i++;
352     } while (*pv);
353 #ifdef VFORK
354     hits--;
355     Vsav = 0;
356 #endif /* VFORK */
357     xfree((ptr_t) sav);
358     pexerr();
359 }
360 
361 static void
362 pexerr()
363 {
364     /* Couldn't find the damn thing */
365     if (expath) {
366 	setname(short2str(expath));
367 #ifdef VFORK
368 	Vexpath = 0;
369 #endif /* VFORK */
370 	xfree((ptr_t) expath);
371 	expath = 0;
372     }
373     else
374 	setname("");
375     if (exerr)
376 	stderror(ERR_NAME | ERR_STRING, exerr);
377     stderror(ERR_NAME | ERR_COMMAND);
378 }
379 
380 /*
381  * Execute command f, arg list t.
382  * Record error message if not found.
383  * Also do shell scripts here.
384  */
385 static void
386 texec(sf, st)
387     Char   *sf;
388     register Char **st;
389 {
390     register char **t;
391     register char *f;
392     register struct varent *v;
393     Char  **vp;
394     Char   *lastsh[2];
395     char    pref[2];
396     int     fd;
397     Char   *st0, **ost;
398 
399     /* The order for the conversions is significant */
400     t = short2blk(st);
401     f = short2str(sf);
402 #ifdef VFORK
403     Vt = t;
404 #endif /* VFORK */
405     errno = 0;			/* don't use a previous error */
406 #ifdef apollo
407     /*
408      * If we try to execute an nfs mounted directory on the apollo, we
409      * hang forever. So until apollo fixes that..
410      */
411     {
412 	struct stat stb;
413 	if (stat(f, &stb) == 0 && S_ISDIR(stb.st_mode))
414 	    errno = EISDIR;
415     }
416     if (errno == 0)
417 #endif /* apollo */
418     {
419 #ifdef ISC_POSIX_EXEC_BUG
420 	__setostype(0);		/* "0" is "__OS_SYSV" in <sys/user.h> */
421 #endif /* ISC_POSIX_EXEC_BUG */
422 	(void) execv(f, t);
423 #ifdef ISC_POSIX_EXEC_BUG
424 	__setostype(1);		/* "1" is "__OS_POSIX" in <sys/user.h> */
425 #endif /* ISC_POSIX_EXEC_BUG */
426     }
427 #ifdef VFORK
428     Vt = 0;
429 #endif /* VFORK */
430     blkfree((Char **) t);
431     switch (errno) {
432 
433     case ENOEXEC:
434 #ifdef WINNT_NATIVE
435 		nt_feed_to_cmd(f,t);
436 #endif /* WINNT_NATIVE */
437 	/*
438 	 * From: casper@fwi.uva.nl (Casper H.S. Dik) If we could not execute
439 	 * it, don't feed it to the shell if it looks like a binary!
440 	 */
441 	if ((fd = open(f, O_RDONLY|O_LARGEFILE)) != -1) {
442 	    int nread;
443 #ifdef O_TEXT
444 	    setmode(fd, O_TEXT);
445 #endif
446 	    if ((nread = read(fd, (char *) pref, 2)) == 2) {
447 		if (!Isprint(pref[0]) && (pref[0] != '\n' && pref[0] != '\t')) {
448 		    (void) close(fd);
449 		    /*
450 		     * We *know* what ENOEXEC means.
451 		     */
452 		    stderror(ERR_ARCH, f, strerror(errno));
453 		}
454 	    }
455 	    else if (nread < 0 && errno != EINTR) {
456 #ifdef convex
457 		/* need to print error incase the file is migrated */
458 		stderror(ERR_SYSTEM, f, strerror(errno));
459 #endif
460 	    }
461 #ifdef _PATH_BSHELL
462 	    else {
463 		pref[0] = '#';
464 		pref[1] = '\0';
465 	    }
466 #endif
467 	}
468 #ifdef HASHBANG
469 	if (fd == -1 ||
470 	    pref[0] != '#' || pref[1] != '!' || hashbang(fd, &vp) == -1) {
471 #endif /* HASHBANG */
472 	/*
473 	 * If there is an alias for shell, then put the words of the alias in
474 	 * front of the argument list replacing the command name. Note no
475 	 * interpretation of the words at this point.
476 	 */
477 	    v = adrof1(STRshell, &aliases);
478 	    if (v == NULL || v->vec == NULL) {
479 		vp = lastsh;
480 		vp[0] = adrof(STRshell) ? varval(STRshell) : STR_SHELLPATH;
481 		vp[1] = NULL;
482 #ifdef _PATH_BSHELL
483 		if (fd != -1
484 # ifndef ISC	/* Compatible with ISC's /bin/csh */
485 		    && pref[0] != '#'
486 # endif /* ISC */
487 		    )
488 		    vp[0] = STR_BSHELL;
489 #endif
490 		vp = saveblk(vp);
491 	    }
492 	    else
493 		vp = saveblk(v->vec);
494 #ifdef HASHBANG
495 	}
496 #endif /* HASHBANG */
497 	if (fd != -1)
498 	    (void) close(fd);
499 
500 	st0 = st[0];
501 	st[0] = sf;
502 	ost = st;
503 	st = blkspl(vp, st);	/* Splice up the new arglst */
504 	ost[0] = st0;
505 	sf = *st;
506 	/* The order for the conversions is significant */
507 	t = short2blk(st);
508 	f = short2str(sf);
509 	xfree((ptr_t) st);
510 	blkfree((Char **) vp);
511 #ifdef VFORK
512 	Vt = t;
513 #endif /* VFORK */
514 #ifdef ISC_POSIX_EXEC_BUG
515 	__setostype(0);		/* "0" is "__OS_SYSV" in <sys/user.h> */
516 #endif /* ISC_POSIX_EXEC_BUG */
517 	(void) execv(f, t);
518 #ifdef ISC_POSIX_EXEC_BUG
519 	__setostype(1);		/* "1" is "__OS_POSIX" in <sys/user.h> */
520 #endif /* ISC_POSIX_EXEC_BUG */
521 #ifdef VFORK
522 	Vt = 0;
523 #endif /* VFORK */
524 	blkfree((Char **) t);
525 	/* The sky is falling, the sky is falling! */
526 	stderror(ERR_SYSTEM, f, strerror(errno));
527 	break;
528 
529     case ENOMEM:
530 	stderror(ERR_SYSTEM, f, strerror(errno));
531 	break;
532 
533 #ifdef _IBMR2
534     case 0:			/* execv fails and returns 0! */
535 #endif /* _IBMR2 */
536     case ENOENT:
537 	break;
538 
539     default:
540 	if (exerr == 0) {
541 	    exerr = strerror(errno);
542 	    if (expath)
543 		xfree((ptr_t) expath);
544 	    expath = Strsave(sf);
545 #ifdef VFORK
546 	    Vexpath = expath;
547 #endif /* VFORK */
548 	}
549 	break;
550     }
551 }
552 
553 /*ARGSUSED*/
554 void
555 execash(t, kp)
556     Char  **t;
557     register struct command *kp;
558 {
559     int     saveIN, saveOUT, saveDIAG, saveSTD;
560     int     oSHIN;
561     int     oSHOUT;
562     int     oSHDIAG;
563     int     oOLDSTD;
564     jmp_buf_t osetexit;
565     int	    my_reenter;
566     int     odidfds;
567 #ifndef CLOSE_ON_EXEC
568     int	    odidcch;
569 #endif /* CLOSE_ON_EXEC */
570     signalfun_t osigint, osigquit, osigterm;
571 
572     USE(t);
573     if (chkstop == 0 && setintr)
574 	panystop(0);
575     /*
576      * Hmm, we don't really want to do that now because we might
577      * fail, but what is the choice
578      */
579     rechist(NULL, adrof(STRsavehist) != NULL);
580 
581 
582     osigint  = signal(SIGINT, parintr);
583     osigquit = signal(SIGQUIT, parintr);
584     osigterm = signal(SIGTERM, parterm);
585 
586     odidfds = didfds;
587 #ifndef CLOSE_ON_EXEC
588     odidcch = didcch;
589 #endif /* CLOSE_ON_EXEC */
590     oSHIN = SHIN;
591     oSHOUT = SHOUT;
592     oSHDIAG = SHDIAG;
593     oOLDSTD = OLDSTD;
594 
595     saveIN = dcopy(SHIN, -1);
596     saveOUT = dcopy(SHOUT, -1);
597     saveDIAG = dcopy(SHDIAG, -1);
598     saveSTD = dcopy(OLDSTD, -1);
599 
600     lshift(kp->t_dcom, 1);
601 
602     getexit(osetexit);
603 
604     /* PWP: setjmp/longjmp bugfix for optimizing compilers */
605 #ifdef cray
606     my_reenter = 1;             /* assume non-zero return val */
607     if (setexit() == 0) {
608         my_reenter = 0;         /* Oh well, we were wrong */
609 #else /* !cray */
610     if ((my_reenter = setexit()) == 0) {
611 #endif /* cray */
612 	SHIN = dcopy(0, -1);
613 	SHOUT = dcopy(1, -1);
614 	SHDIAG = dcopy(2, -1);
615 #ifndef CLOSE_ON_EXEC
616 	didcch = 0;
617 #endif /* CLOSE_ON_EXEC */
618 	didfds = 0;
619 	/*
620 	 * Decrement the shell level
621 	 */
622 	shlvl(-1);
623 #ifdef WINNT_NATIVE
624 	__nt_really_exec=1;
625 #endif /* WINNT_NATIVE */
626 	doexec(kp, 1);
627     }
628 
629     (void) sigset(SIGINT, osigint);
630     (void) sigset(SIGQUIT, osigquit);
631     (void) sigset(SIGTERM, osigterm);
632 
633     doneinp = 0;
634 #ifndef CLOSE_ON_EXEC
635     didcch = odidcch;
636 #endif /* CLOSE_ON_EXEC */
637     didfds = odidfds;
638     (void) close(SHIN);
639     (void) close(SHOUT);
640     (void) close(SHDIAG);
641     (void) close(OLDSTD);
642     SHIN = dmove(saveIN, oSHIN);
643     SHOUT = dmove(saveOUT, oSHOUT);
644     SHDIAG = dmove(saveDIAG, oSHDIAG);
645     OLDSTD = dmove(saveSTD, oOLDSTD);
646 
647     resexit(osetexit);
648     if (my_reenter)
649 	stderror(ERR_SILENT);
650 }
651 
652 void
653 xechoit(t)
654     Char  **t;
655 {
656     if (adrof(STRecho)) {
657 	int odidfds = didfds;
658 	flush();
659 	haderr = 1;
660 	didfds = 0;
661 	blkpr(t), xputchar('\n');
662 	flush();
663 	didfds = odidfds;
664 	haderr = 0;
665     }
666 }
667 
668 /*ARGSUSED*/
669 void
670 dohash(vv, c)
671     Char **vv;
672     struct command *c;
673 {
674 #ifdef COMMENT
675     struct stat stb;
676 #endif
677     DIR    *dirp;
678     register struct dirent *dp;
679     int     i = 0;
680     struct varent *v = adrof(STRpath);
681     Char  **pv;
682     int hashval;
683 #ifdef WINNT_NATIVE
684     int is_windir; /* check if it is the windows directory */
685     USE(hashval);
686 #endif /* WINNT_NATIVE */
687 
688     USE(c);
689 #ifdef FASTHASH
690     if (vv && vv[1]) {
691         uhashlength = atoi(short2str(vv[1]));
692         if (vv[2]) {
693 	    uhashwidth = atoi(short2str(vv[2]));
694 	    if ((uhashwidth != sizeof(unsigned char)) &&
695 	        (uhashwidth != sizeof(unsigned short)) &&
696 	        (uhashwidth != sizeof(unsigned long)))
697 	        uhashwidth = 0;
698 	    if (vv[3])
699 		hashdebug = atoi(short2str(vv[3]));
700         }
701     }
702 
703     if (uhashwidth)
704 	hashwidth = uhashwidth;
705     else {
706 	hashwidth = 0;
707 	if (v == NULL)
708 	    return;
709 	for (pv = v->vec; pv && *pv; pv++, hashwidth++)
710 	    continue;
711 	if (hashwidth <= widthof(unsigned char))
712 	    hashwidth = sizeof(unsigned char);
713 	else if (hashwidth <= widthof(unsigned short))
714 	    hashwidth = sizeof(unsigned short);
715 	else if (hashwidth <= widthof(unsigned int))
716 	    hashwidth = sizeof(unsigned int);
717 	else
718 	    hashwidth = sizeof(unsigned long);
719     }
720 
721     if (uhashlength)
722 	hashlength = uhashlength;
723     else
724         hashlength = hashwidth * (8*64);/* "average" files per dir in path */
725 
726     if (xhash)
727         xfree((ptr_t) xhash);
728     xhash = (unsigned long *) xcalloc((size_t) (hashlength * hashwidth),
729 				      (size_t) 1);
730 #endif /* FASTHASH */
731 
732     (void) getusername(NULL);	/* flush the tilde cashe */
733     tw_cmd_free();
734     havhash = 1;
735     if (v == NULL)
736 	return;
737     for (pv = v->vec; pv && *pv; pv++, i++) {
738 	if (!ABSOLUTEP(pv[0]))
739 	    continue;
740 	dirp = opendir(short2str(*pv));
741 	if (dirp == NULL)
742 	    continue;
743 #ifdef COMMENT			/* this isn't needed.  opendir won't open
744 				 * non-dirs */
745 	if (fstat(dirp->dd_fd, &stb) < 0 || !S_ISDIR(stb.st_mode)) {
746 	    (void) closedir(dirp);
747 	    continue;
748 	}
749 #endif
750 #ifdef WINNT_NATIVE
751 	is_windir = nt_check_if_windir(short2str(*pv));
752 #endif /* WINNT_NATIVE */
753 	while ((dp = readdir(dirp)) != NULL) {
754 	    if (dp->d_ino == 0)
755 		continue;
756 	    if (dp->d_name[0] == '.' &&
757 		(dp->d_name[1] == '\0' ||
758 		 (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
759 		continue;
760 #ifdef WINNT_NATIVE
761 	    nt_check_name_and_hash(is_windir, dp->d_name, i);
762 #else /* !WINNT_NATIVE*/
763 #if defined(_UWIN) || defined(__CYGWIN__)
764 	    /* Turn foo.{exe,com,bat} into foo since UWIN's readdir returns
765 	     * the file with the .exe, .com, .bat extension
766 	     */
767 	    {
768 		size_t	ext = strlen(dp->d_name) - 4;
769 		if ((ext > 0) && (strcasecmp(&dp->d_name[ext], ".exe") == 0 ||
770 				  strcasecmp(&dp->d_name[ext], ".bat") == 0 ||
771 				  strcasecmp(&dp->d_name[ext], ".com") == 0))
772 		    {
773 			dp->d_name[ext] = '\0';
774 #if defined(__CYGWIN__)
775 			strlwr(dp->d_name);
776 #endif /* __CYGWIN__ */
777 		    }
778 	    }
779 #endif /* _UWIN || __CYGWIN__ */
780 # ifdef FASTHASH
781 	    hashval = hashname(str2short(dp->d_name));
782 	    bis(hashval, i);
783 	    if (hashdebug & 1)
784 	        xprintf(CGETS(13, 1, "hash=%-4d dir=%-2d prog=%s\n"),
785 		        hashname(str2short(dp->d_name)), i, dp->d_name);
786 # else /* OLD HASH */
787 	    hashval = hash(hashname(str2short(dp->d_name)), i);
788 	    bis(xhash, hashval);
789 # endif /* FASTHASH */
790 	    /* tw_add_comm_name (dp->d_name); */
791 #endif /* WINNT_NATIVE */
792 	}
793 	(void) closedir(dirp);
794     }
795 }
796 
797 /*ARGSUSED*/
798 void
799 dounhash(v, c)
800     Char **v;
801     struct command *c;
802 {
803     USE(c);
804     USE(v);
805     havhash = 0;
806 #ifdef FASTHASH
807     if (xhash) {
808        xfree((ptr_t) xhash);
809        xhash = NULL;
810     }
811 #endif /* FASTHASH */
812 }
813 
814 /*ARGSUSED*/
815 void
816 hashstat(v, c)
817     Char **v;
818     struct command *c;
819 {
820     USE(c);
821     USE(v);
822 #ifdef FASTHASH
823    if (havhash && hashlength && hashwidth)
824       xprintf(CGETS(13, 2, "%d hash buckets of %d bits each\n"),
825 	      hashlength, hashwidth*8);
826    if (hashdebug)
827       xprintf(CGETS(13, 3, "debug mask = 0x%08x\n"), hashdebug);
828 #endif /* FASTHASH */
829 #ifdef VFORK
830    if (hits + misses)
831       xprintf(CGETS(13, 4, "%d hits, %d misses, %d%%\n"),
832 	      hits, misses, 100 * hits / (hits + misses));
833 #endif
834 }
835 
836 
837 /*
838  * Hash a command name.
839  */
840 int
841 hashname(cp)
842     register Char *cp;
843 {
844     register unsigned long h;
845 
846     for (h = 0; *cp; cp++)
847 	h = hash(h, *cp);
848     return ((int) h);
849 }
850 
851 static int
852 iscommand(name)
853     Char   *name;
854 {
855     register Char **pv;
856     register Char *sav;
857     register struct varent *v;
858     register bool slash = any(short2str(name), '/');
859     register int hashval, i;
860 
861     v = adrof(STRpath);
862     if (v == NULL || v->vec == NULL || v->vec[0] == NULL || slash)
863 	pv = justabs;
864     else
865 	pv = v->vec;
866     sav = Strspl(STRslash, name);	/* / command name for postpending */
867     hashval = havhash ? hashname(name) : 0;
868     i = 0;
869     do {
870 	if (!slash && ABSOLUTEP(pv[0]) && havhash) {
871 #ifdef FASTHASH
872 	    if (!bit(hashval, i))
873 		goto cont;
874 #else /* OLDHASH */
875 	    int hashval1 = hash(hashval, i);
876 	    if (!bit(xhash, hashval1))
877 		goto cont;
878 #endif /* FASTHASH */
879 	}
880 	if (pv[0][0] == 0 || eq(pv[0], STRdot)) {	/* don't make ./xxx */
881 	    if (executable(NULL, name, 0)) {
882 		xfree((ptr_t) sav);
883 		return i + 1;
884 	    }
885 	}
886 	else {
887 	    if (executable(*pv, sav, 0)) {
888 		xfree((ptr_t) sav);
889 		return i + 1;
890 	    }
891 	}
892 cont:
893 	pv++;
894 	i++;
895     } while (*pv);
896     xfree((ptr_t) sav);
897     return 0;
898 }
899 
900 /* Also by:
901  *  Andreas Luik <luik@isaak.isa.de>
902  *  I S A  GmbH - Informationssysteme fuer computerintegrierte Automatisierung
903  *  Azenberstr. 35
904  *  D-7000 Stuttgart 1
905  *  West-Germany
906  * is the executable() routine below and changes to iscommand().
907  * Thanks again!!
908  */
909 
910 #ifndef WINNT_NATIVE
911 /*
912  * executable() examines the pathname obtained by concatenating dir and name
913  * (dir may be NULL), and returns 1 either if it is executable by us, or
914  * if dir_ok is set and the pathname refers to a directory.
915  * This is a bit kludgy, but in the name of optimization...
916  */
917 int
918 executable(dir, name, dir_ok)
919     Char   *dir, *name;
920     bool    dir_ok;
921 {
922     struct stat stbuf;
923     Char    path[MAXPATHLEN + 1];
924     char   *strname;
925     (void) memset(path, 0, sizeof(path));
926 
927     if (dir && *dir) {
928 	copyn(path, dir, MAXPATHLEN);
929 	catn(path, name, MAXPATHLEN);
930 	strname = short2str(path);
931     }
932     else
933 	strname = short2str(name);
934 
935     return (stat(strname, &stbuf) != -1 &&
936 	    ((dir_ok && S_ISDIR(stbuf.st_mode)) ||
937 	     (S_ISREG(stbuf.st_mode) &&
938     /* save time by not calling access() in the hopeless case */
939 	      (stbuf.st_mode & (S_IXOTH | S_IXGRP | S_IXUSR)) &&
940 	      access(strname, X_OK) == 0
941 	)));
942 }
943 #endif /*!WINNT_NATIVE*/
944 
945 int
946 tellmewhat(lexp, str)
947     struct wordent *lexp;
948     Char *str;
949 {
950     register int i;
951     register struct biltins *bptr;
952     register struct wordent *sp = lexp->next;
953     bool    aliased = 0, found;
954     Char   *s0, *s1, *s2, *cmd;
955     Char    qc;
956 
957     if (adrof1(sp->word, &aliases)) {
958 	alias(lexp);
959 	sp = lexp->next;
960 	aliased = 1;
961     }
962 
963     s0 = sp->word;		/* to get the memory freeing right... */
964 
965     /* handle quoted alias hack */
966     if ((*(sp->word) & (QUOTE | TRIM)) == QUOTE)
967 	(sp->word)++;
968 
969     /* do quoting, if it hasn't been done */
970     s1 = s2 = sp->word;
971     while (*s2)
972 	switch (*s2) {
973 	case '\'':
974 	case '"':
975 	    qc = *s2++;
976 	    while (*s2 && *s2 != qc)
977 		*s1++ = *s2++ | QUOTE;
978 	    if (*s2)
979 		s2++;
980 	    break;
981 	case '\\':
982 	    if (*++s2)
983 		*s1++ = *s2++ | QUOTE;
984 	    break;
985 	default:
986 	    *s1++ = *s2++;
987 	}
988     *s1 = '\0';
989 
990     for (bptr = bfunc; bptr < &bfunc[nbfunc]; bptr++) {
991 	if (eq(sp->word, str2short(bptr->bname))) {
992 	    if (str == NULL) {
993 		if (aliased)
994 		    prlex(lexp);
995 		xprintf(CGETS(13, 5, "%S: shell built-in command.\n"),
996 			      sp->word);
997 		flush();
998 	    }
999 	    else
1000 		(void) Strcpy(str, sp->word);
1001 	    sp->word = s0;	/* we save and then restore this */
1002 	    return TRUE;
1003 	}
1004     }
1005 #ifdef WINNT_NATIVE
1006     for (bptr = nt_bfunc; bptr < &nt_bfunc[nt_nbfunc]; bptr++) {
1007 	if (eq(sp->word, str2short(bptr->bname))) {
1008 	    if (str == NULL) {
1009 		if (aliased)
1010 		    prlex(lexp);
1011 		xprintf(CGETS(13, 5, "%S: shell built-in command.\n"),
1012 			      sp->word);
1013 		flush();
1014 	    }
1015 	    else
1016 		(void) Strcpy(str, sp->word);
1017 	    sp->word = s0;	/* we save and then restore this */
1018 	    return TRUE;
1019 	}
1020     }
1021 #endif /* WINNT_NATIVE*/
1022 
1023     sp->word = cmd = globone(sp->word, G_IGNORE);
1024 
1025     if ((i = iscommand(sp->word)) != 0) {
1026 	register Char **pv;
1027 	register struct varent *v;
1028 	bool    slash = any(short2str(sp->word), '/');
1029 
1030 	v = adrof(STRpath);
1031 	if (v == NULL || v->vec == NULL || v->vec[0] == NULL || slash)
1032 	    pv = justabs;
1033 	else
1034 	    pv = v->vec;
1035 
1036 	while (--i)
1037 	    pv++;
1038 	if (pv[0][0] == 0 || eq(pv[0], STRdot)) {
1039 	    if (!slash) {
1040 		sp->word = Strspl(STRdotsl, sp->word);
1041 		prlex(lexp);
1042 		xfree((ptr_t) sp->word);
1043 	    }
1044 	    else
1045 		prlex(lexp);
1046 	}
1047 	else {
1048 	    s1 = Strspl(*pv, STRslash);
1049 	    sp->word = Strspl(s1, sp->word);
1050 	    xfree((ptr_t) s1);
1051 	    if (str == NULL)
1052 		prlex(lexp);
1053 	    else
1054 		(void) Strcpy(str, sp->word);
1055 	    xfree((ptr_t) sp->word);
1056 	}
1057 	found = 1;
1058     }
1059     else {
1060 	if (str == NULL) {
1061 	    if (aliased)
1062 		prlex(lexp);
1063 	    xprintf(CGETS(13, 6, "%S: Command not found.\n"), sp->word);
1064 	    flush();
1065 	}
1066 	else
1067 	    (void) Strcpy(str, sp->word);
1068 	found = 0;
1069     }
1070     sp->word = s0;		/* we save and then restore this */
1071     xfree((ptr_t) cmd);
1072     return found;
1073 }
1074 
1075 /*
1076  * Builtin to look at and list all places a command may be defined:
1077  * aliases, shell builtins, and the path.
1078  *
1079  * Marc Horowitz <marc@mit.edu>
1080  * MIT Student Information Processing Board
1081  */
1082 
1083 /*ARGSUSED*/
1084 void
1085 dowhere(v, c)
1086     register Char **v;
1087     struct command *c;
1088 {
1089     int found = 1;
1090     USE(c);
1091     for (v++; *v; v++)
1092 	found &= find_cmd(*v, 1);
1093     /* Make status nonzero if any command is not found. */
1094     if (!found)
1095       set(STRstatus, Strsave(STR1), VAR_READWRITE);
1096 }
1097 
1098 int
1099 find_cmd(cmd, prt)
1100     Char *cmd;
1101     int prt;
1102 {
1103     struct varent *var;
1104     struct biltins *bptr;
1105     Char **pv;
1106     Char *sv;
1107     int hashval, i, ex, rval = 0;
1108 
1109     if (prt && any(short2str(cmd), '/')) {
1110 	xprintf(CGETS(13, 7, "where: / in command makes no sense\n"));
1111 	return rval;
1112     }
1113 
1114     /* first, look for an alias */
1115 
1116     if (prt && adrof1(cmd, &aliases)) {
1117 	if ((var = adrof1(cmd, &aliases)) != NULL) {
1118 	    xprintf(CGETS(13, 8, "%S is aliased to "), cmd);
1119 	    if (var->vec != NULL)
1120 		blkpr(var->vec);
1121 	    xputchar('\n');
1122 	    rval = 1;
1123 	}
1124     }
1125 
1126     /* next, look for a shell builtin */
1127 
1128     for (bptr = bfunc; bptr < &bfunc[nbfunc]; bptr++) {
1129 	if (eq(cmd, str2short(bptr->bname))) {
1130 	    rval = 1;
1131 	    if (prt)
1132 		xprintf(CGETS(13, 9, "%S is a shell built-in\n"), cmd);
1133 	    else
1134 		return rval;
1135 	}
1136     }
1137 #ifdef WINNT_NATIVE
1138     for (bptr = nt_bfunc; bptr < &nt_bfunc[nt_nbfunc]; bptr++) {
1139 	if (eq(cmd, str2short(bptr->bname))) {
1140 	    rval = 1;
1141 	    if (prt)
1142 		xprintf(CGETS(13, 9, "%S is a shell built-in\n"), cmd);
1143 	    else
1144 		return rval;
1145 	}
1146     }
1147 #endif /* WINNT_NATIVE*/
1148 
1149     /* last, look through the path for the command */
1150 
1151     if ((var = adrof(STRpath)) == NULL)
1152 	return rval;
1153 
1154     hashval = havhash ? hashname(cmd) : 0;
1155 
1156     sv = Strspl(STRslash, cmd);
1157 
1158     for (pv = var->vec, i = 0; pv && *pv; pv++, i++) {
1159 	if (havhash && !eq(*pv, STRdot)) {
1160 #ifdef FASTHASH
1161 	    if (!bit(hashval, i))
1162 		continue;
1163 #else /* OLDHASH */
1164 	    int hashval1 = hash(hashval, i);
1165 	    if (!bit(xhash, hashval1))
1166 		continue;
1167 #endif /* FASTHASH */
1168 	}
1169 	ex = executable(*pv, sv, 0);
1170 #ifdef FASTHASH
1171 	if (!ex && (hashdebug & 2)) {
1172 	    xprintf(CGETS(13, 10, "hash miss: "));
1173 	    ex = 1;	/* Force printing */
1174 	}
1175 #endif /* FASTHASH */
1176 	if (ex) {
1177 	    rval = 1;
1178 	    if (prt) {
1179 		xprintf("%S/", *pv);
1180 		xprintf("%S\n", cmd);
1181 	    }
1182 	    else
1183 		return rval;
1184 	}
1185     }
1186     xfree((ptr_t) sv);
1187     return rval;
1188 }
1189 #ifdef WINNT_NATIVE
1190 int hashval_extern(cp)
1191 	Char *cp;
1192 {
1193 	return havhash?hashname(cp):0;
1194 }
1195 int bit_extern(val,i)
1196 	int val;
1197 	int i;
1198 {
1199 	return bit(val,i);
1200 }
1201 void bis_extern(val,i)
1202 	int val;
1203 	int i;
1204 {
1205 	bis(val,i);
1206 }
1207 #endif /* WINNT_NATIVE */
1208 
1209