xref: /netbsd-src/bin/csh/dir.c (revision ae1bfcddc410612bc8c58b807e1830becb69a24c)
1 /*-
2  * Copyright (c) 1980, 1991 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. 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 
34 #ifndef lint
35 /*static char sccsid[] = "from: @(#)dir.c	5.12 (Berkeley) 6/27/91";*/
36 static char rcsid[] = "$Id: dir.c,v 1.5 1993/08/01 19:00:49 mycroft Exp $";
37 #endif /* not lint */
38 
39 #include <sys/param.h>
40 #include <sys/stat.h>
41 #include <errno.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <unistd.h>
45 #if __STDC__
46 # include <stdarg.h>
47 #else
48 # include <varargs.h>
49 #endif
50 
51 #include "csh.h"
52 #include "dir.h"
53 #include "extern.h"
54 
55 /* Directory management. */
56 
57 static struct directory
58 		*dfind __P((Char *));
59 static Char 	*dfollow __P((Char *));
60 static void 	 printdirs __P((void));
61 static Char 	*dgoto __P((Char *));
62 static void 	 dnewcwd __P((struct directory *));
63 static void 	 dset __P((Char *));
64 
65 struct directory dhead;		/* "head" of loop */
66 int     printd;			/* force name to be printed */
67 
68 static int dirflag = 0;
69 
70 /*
71  * dinit - initialize current working directory
72  */
73 void
74 dinit(hp)
75     Char   *hp;
76 {
77     register char *tcp;
78     register Char *cp;
79     register struct directory *dp;
80     char    path[MAXPATHLEN];
81     static char *emsg = "csh: Trying to start from \"%s\"\n";
82 
83     /* Don't believe the login shell home, because it may be a symlink */
84     tcp = getwd(path);		/* see ngetwd.c for System V version */
85     if (tcp == NULL || *tcp == '\0') {
86 	(void) xprintf("csh: %s\n", path);
87 	if (hp && *hp) {
88 	    tcp = short2str(hp);
89 	    (void) xprintf(emsg, tcp);
90 	    if (chdir(tcp) == -1)
91 		cp = NULL;
92 	    else
93 		cp = hp;
94 	}
95 	else
96 	    cp = NULL;
97 	if (cp == NULL) {
98 	    (void) xprintf(emsg, "/");
99 	    if (chdir("/") == -1)
100 		/* I am not even try to print an error message! */
101 		xexit(1);
102 	    cp = SAVE("/");
103 	}
104     }
105     else {
106 	struct stat swd, shp;
107 
108 	/*
109 	 * See if $HOME is the working directory we got and use that
110 	 */
111 	if (hp && *hp &&
112 	    stat(tcp, &swd) != -1 && stat(short2str(hp), &shp) != -1 &&
113 	    swd.st_dev == shp.st_dev && swd.st_ino == shp.st_ino)
114 	    cp = hp;
115 	else {
116 	    char   *cwd;
117 
118 	    /*
119 	     * use PWD if we have it (for subshells)
120 	     */
121 	    if (cwd = getenv("PWD")) {
122 		if (stat(cwd, &shp) != -1 && swd.st_dev == shp.st_dev &&
123 		    swd.st_ino == shp.st_ino)
124 		    tcp = cwd;
125 	    }
126 	    cp = dcanon(str2short(tcp), STRNULL);
127 	}
128     }
129 
130     dp = (struct directory *) xcalloc(sizeof(struct directory), 1);
131     dp->di_name = Strsave(cp);
132     dp->di_count = 0;
133     dhead.di_next = dhead.di_prev = dp;
134     dp->di_next = dp->di_prev = &dhead;
135     printd = 0;
136     dnewcwd(dp);
137 }
138 
139 static void
140 dset(dp)
141 Char *dp;
142 {
143     /*
144      * Don't call set() directly cause if the directory contains ` or
145      * other junk characters glob will fail.
146      */
147     register Char **vec = (Char **) xmalloc((size_t) (2 * sizeof(Char **)));
148 
149     vec[0] = Strsave(dp);
150     vec[1] = 0;
151     setq(STRcwd, vec, &shvhed);
152     Setenv(STRPWD, dp);
153 }
154 
155 #define DIR_LONG 1
156 #define DIR_VERT 2
157 #define DIR_LINE 4
158 
159 static void
160 skipargs(v, str)
161     Char ***v;
162     char   *str;
163 {
164     Char  **n = *v, *s;
165 
166     dirflag = 0;
167     for (n++; *n != NULL && (*n)[0] == '-'; n++)
168 	for (s = &((*n)[1]); *s; s++)
169 	    switch (*s) {
170 	    case 'l':
171 		dirflag |= DIR_LONG;
172 		break;
173 	    case 'v':
174 		dirflag |= DIR_VERT;
175 		break;
176 	    case 'n':
177 		dirflag |= DIR_LINE;
178 		break;
179 	    default:
180 		stderror(ERR_DIRUS, short2str(**v), str);
181 		break;
182 	    }
183     *v = n;
184 }
185 
186 /*
187  * dodirs - list all directories in directory loop
188  */
189 void
190 dodirs(v)
191     Char  **v;
192 {
193     skipargs(&v, "");
194 
195     if (*v != NULL)
196 	stderror(ERR_DIRUS, "dirs", "");
197     printdirs();
198 }
199 
200 static void
201 printdirs()
202 {
203     register struct directory *dp;
204     Char   *s, *hp = value(STRhome);
205     int     idx, len, cur;
206 
207     if (*hp == '\0')
208 	hp = NULL;
209     dp = dcwd;
210     idx = 0;
211     cur = 0;
212     do {
213 	if (dp == &dhead)
214 	    continue;
215 	if (dirflag & DIR_VERT) {
216 	    xprintf("%d\t", idx++);
217 	    cur = 0;
218 	}
219 	if (!(dirflag & DIR_LONG) && hp != NULL && !eq(hp, STRslash) &&
220 	    prefix(hp, dp->di_name))
221 	    len = Strlen(s = (dp->di_name + Strlen(hp))) + 2;
222 	else
223 	    len = Strlen(s = dp->di_name) + 1;
224 
225 	cur += len;
226 	if ((dirflag & DIR_LINE) && cur >= 80 - 1 && len < 80) {
227 	    xprintf("\n");
228 	    cur = len;
229 	}
230 	xprintf(s != dp->di_name ? "~%s%c" : "%s%c",
231 		short2str(s), (dirflag & DIR_VERT) ? '\n' : ' ');
232     } while ((dp = dp->di_prev) != dcwd);
233     if (!(dirflag & DIR_VERT))
234 	xprintf("\n");
235 }
236 
237 void
238 dtildepr(home, dir)
239     register Char *home, *dir;
240 {
241 
242     if (!eq(home, STRslash) && prefix(home, dir))
243 	xprintf("~%s", short2str(dir + Strlen(home)));
244     else
245 	xprintf("%s", short2str(dir));
246 }
247 
248 void
249 dtilde()
250 {
251     struct directory *d = dcwd;
252 
253     do {
254 	if (d == &dhead)
255 	    continue;
256 	d->di_name = dcanon(d->di_name, STRNULL);
257     } while ((d = d->di_prev) != dcwd);
258 
259     dset(dcwd->di_name);
260 }
261 
262 
263 /* dnormalize():
264  *	If the name starts with . or .. then we might need to normalize
265  *	it depending on the symbolic link flags
266  */
267 Char   *
268 dnormalize(cp)
269     Char   *cp;
270 {
271 
272 #define UC (unsigned char)
273 #define ISDOT(c) (UC(c)[0] == '.' && ((UC(c)[1] == '\0') || (UC(c)[1] == '/')))
274 #define ISDOTDOT(c) (UC(c)[0] == '.' && ISDOT(&((c)[1])))
275 
276     if ((unsigned char) cp[0] == '/')
277 	return (Strsave(cp));
278 
279     if (adrof(STRignore_symlinks)) {
280 	int     dotdot = 0;
281 	Char   *dp, *cwd;
282 
283 	cwd = (Char *) xmalloc((size_t) ((Strlen(dcwd->di_name) + 3) *
284 					 sizeof(Char)));
285 	(void) Strcpy(cwd, dcwd->di_name);
286 
287 	/*
288 	 * Ignore . and count ..'s
289 	 */
290 	while (*cp) {
291 	    if (ISDOT(cp)) {
292 		if (*++cp)
293 		    cp++;
294 	    }
295 	    else if (ISDOTDOT(cp)) {
296 		dotdot++;
297 		cp += 2;
298 		if (*cp)
299 		    cp++;
300 	    }
301 	    else
302 		break;
303 	}
304 	while (dotdot > 0)
305 	    if ((dp = Strrchr(cwd, '/'))) {
306 		*dp = '\0';
307 		dotdot--;
308 	    }
309 	    else
310 		break;
311 
312 	if (*cp) {
313 	    cwd[dotdot = Strlen(cwd)] = '/';
314 	    cwd[dotdot + 1] = '\0';
315 	    dp = Strspl(cwd, cp);
316 	    xfree((ptr_t) cwd);
317 	    return dp;
318 	}
319 	else {
320 	    if (!*cwd) {
321 		cwd[0] = '/';
322 		cwd[1] = '\0';
323 	    }
324 	    return cwd;
325 	}
326     }
327     return Strsave(cp);
328 }
329 
330 /*
331  * dochngd - implement chdir command.
332  */
333 void
334 dochngd(v)
335     Char  **v;
336 {
337     register Char *cp;
338     register struct directory *dp;
339 
340     skipargs(&v, " [<dir>]");
341     printd = 0;
342     if (*v == NULL) {
343 	if ((cp = value(STRhome)) == NULL || *cp == 0)
344 	    stderror(ERR_NAME | ERR_NOHOMEDIR);
345 	if (chdir(short2str(cp)) < 0)
346 	    stderror(ERR_NAME | ERR_CANTCHANGE);
347 	cp = Strsave(cp);
348     }
349     else if (v[1] != NULL) {
350 	stderror(ERR_NAME | ERR_TOOMANY);
351 	/* NOTREACHED */
352 	return;
353     }
354     else if ((dp = dfind(*v)) != 0) {
355 	char   *tmp;
356 
357 	printd = 1;
358 	if (chdir(tmp = short2str(dp->di_name)) < 0)
359 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
360 	dcwd->di_prev->di_next = dcwd->di_next;
361 	dcwd->di_next->di_prev = dcwd->di_prev;
362 	dfree(dcwd);
363 	dnewcwd(dp);
364 	return;
365     }
366     else
367 	cp = dfollow(*v);
368     dp = (struct directory *) xcalloc(sizeof(struct directory), 1);
369     dp->di_name = cp;
370     dp->di_count = 0;
371     dp->di_next = dcwd->di_next;
372     dp->di_prev = dcwd->di_prev;
373     dp->di_prev->di_next = dp;
374     dp->di_next->di_prev = dp;
375     dfree(dcwd);
376     dnewcwd(dp);
377 }
378 
379 static Char *
380 dgoto(cp)
381     Char   *cp;
382 {
383     Char   *dp;
384 
385     if (*cp != '/') {
386 	register Char *p, *q;
387 	int     cwdlen;
388 
389 	for (p = dcwd->di_name; *p++;);
390 	if ((cwdlen = p - dcwd->di_name - 1) == 1)	/* root */
391 	    cwdlen = 0;
392 	for (p = cp; *p++;);
393 	dp = (Char *) xmalloc((size_t)((cwdlen + (p - cp) + 1) * sizeof(Char)));
394 	for (p = dp, q = dcwd->di_name; *p++ = *q++;);
395 	if (cwdlen)
396 	    p[-1] = '/';
397 	else
398 	    p--;		/* don't add a / after root */
399 	for (q = cp; *p++ = *q++;);
400 	xfree((ptr_t) cp);
401 	cp = dp;
402 	dp += cwdlen;
403     }
404     else
405 	dp = cp;
406 
407     cp = dcanon(cp, dp);
408     return cp;
409 }
410 
411 /*
412  * dfollow - change to arg directory; fall back on cdpath if not valid
413  */
414 static Char *
415 dfollow(cp)
416     register Char *cp;
417 {
418     register Char *dp;
419     struct varent *c;
420     char    ebuf[MAXPATHLEN];
421     int serrno;
422 
423     cp = globone(cp, G_ERROR);
424     /*
425      * if we are ignoring symlinks, try to fix relatives now.
426      */
427     dp = dnormalize(cp);
428     if (chdir(short2str(dp)) >= 0) {
429 	xfree((ptr_t) cp);
430 	return dgoto(dp);
431     }
432     else {
433 	xfree((ptr_t) dp);
434 	if (chdir(short2str(cp)) >= 0)
435 	    return dgoto(cp);
436 	serrno = errno;
437     }
438 
439     if (cp[0] != '/' && !prefix(STRdotsl, cp) && !prefix(STRdotdotsl, cp)
440 	&& (c = adrof(STRcdpath))) {
441 	Char  **cdp;
442 	register Char *p;
443 	Char    buf[MAXPATHLEN];
444 
445 	for (cdp = c->vec; *cdp; cdp++) {
446 	    for (dp = buf, p = *cdp; *dp++ = *p++;);
447 	    dp[-1] = '/';
448 	    for (p = cp; *dp++ = *p++;);
449 	    if (chdir(short2str(buf)) >= 0) {
450 		printd = 1;
451 		xfree((ptr_t) cp);
452 		cp = Strsave(buf);
453 		return dgoto(cp);
454 	    }
455 	}
456     }
457     dp = value(cp);
458     if ((dp[0] == '/' || dp[0] == '.') && chdir(short2str(dp)) >= 0) {
459 	xfree((ptr_t) cp);
460 	cp = Strsave(dp);
461 	printd = 1;
462 	return dgoto(cp);
463     }
464     (void) strcpy(ebuf, short2str(cp));
465     xfree((ptr_t) cp);
466     stderror(ERR_SYSTEM, ebuf, strerror(serrno));
467     return (NULL);
468 }
469 
470 
471 /*
472  * dopushd - push new directory onto directory stack.
473  *	with no arguments exchange top and second.
474  *	with numeric argument (+n) bring it to top.
475  */
476 void
477 dopushd(v)
478     Char  **v;
479 {
480     register struct directory *dp;
481 
482     skipargs(&v, " [<dir>|+<n>]");
483     printd = 1;
484     if (*v == NULL) {
485 	char   *tmp;
486 
487 	if ((dp = dcwd->di_prev) == &dhead)
488 	    dp = dhead.di_prev;
489 	if (dp == dcwd)
490 	    stderror(ERR_NAME | ERR_NODIR);
491 	if (chdir(tmp = short2str(dp->di_name)) < 0)
492 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
493 	dp->di_prev->di_next = dp->di_next;
494 	dp->di_next->di_prev = dp->di_prev;
495 	dp->di_next = dcwd->di_next;
496 	dp->di_prev = dcwd;
497 	dcwd->di_next->di_prev = dp;
498 	dcwd->di_next = dp;
499     }
500     else if (v[1] != NULL) {
501 	stderror(ERR_NAME | ERR_TOOMANY);
502 	/* NOTREACHED */
503 	return;
504     }
505     else if (dp = dfind(*v)) {
506 	char   *tmp;
507 
508 	if (chdir(tmp = short2str(dp->di_name)) < 0)
509 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
510     }
511     else {
512 	register Char *ccp;
513 
514 	ccp = dfollow(*v);
515 	dp = (struct directory *) xcalloc(sizeof(struct directory), 1);
516 	dp->di_name = ccp;
517 	dp->di_count = 0;
518 	dp->di_prev = dcwd;
519 	dp->di_next = dcwd->di_next;
520 	dcwd->di_next = dp;
521 	dp->di_next->di_prev = dp;
522     }
523     dnewcwd(dp);
524 }
525 
526 /*
527  * dfind - find a directory if specified by numeric (+n) argument
528  */
529 static struct directory *
530 dfind(cp)
531     register Char *cp;
532 {
533     register struct directory *dp;
534     register int i;
535     register Char *ep;
536 
537     if (*cp++ != '+')
538 	return (0);
539     for (ep = cp; Isdigit(*ep); ep++)
540 	continue;
541     if (*ep)
542 	return (0);
543     i = getn(cp);
544     if (i <= 0)
545 	return (0);
546     for (dp = dcwd; i != 0; i--) {
547 	if ((dp = dp->di_prev) == &dhead)
548 	    dp = dp->di_prev;
549 	if (dp == dcwd)
550 	    stderror(ERR_NAME | ERR_DEEP);
551     }
552     return (dp);
553 }
554 
555 /*
556  * dopopd - pop a directory out of the directory stack
557  *	with a numeric argument just discard it.
558  */
559 void
560 dopopd(v)
561     Char  **v;
562 {
563     register struct directory *dp, *p = NULL;
564 
565     skipargs(&v, " [+<n>]");
566     printd = 1;
567     if (*v == NULL)
568 	dp = dcwd;
569     else if (v[1] != NULL) {
570 	stderror(ERR_NAME | ERR_TOOMANY);
571 	/* NOTREACHED */
572 	return;
573     }
574     else if ((dp = dfind(*v)) == 0)
575 	stderror(ERR_NAME | ERR_BADDIR);
576     if (dp->di_prev == &dhead && dp->di_next == &dhead)
577 	stderror(ERR_NAME | ERR_EMPTY);
578     if (dp == dcwd) {
579 	char   *tmp;
580 
581 	if ((p = dp->di_prev) == &dhead)
582 	    p = dhead.di_prev;
583 	if (chdir(tmp = short2str(p->di_name)) < 0)
584 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
585     }
586     dp->di_prev->di_next = dp->di_next;
587     dp->di_next->di_prev = dp->di_prev;
588     if (dp == dcwd)
589 	dnewcwd(p);
590     else {
591 	printdirs();
592     }
593     dfree(dp);
594 }
595 
596 /*
597  * dfree - free the directory (or keep it if it still has ref count)
598  */
599 void
600 dfree(dp)
601     register struct directory *dp;
602 {
603 
604     if (dp->di_count != 0) {
605 	dp->di_next = dp->di_prev = 0;
606     }
607     else {
608 	xfree((char *) dp->di_name);
609 	xfree((ptr_t) dp);
610     }
611 }
612 
613 /*
614  * dcanon - canonicalize the pathname, removing excess ./ and ../ etc.
615  *	we are of course assuming that the file system is standardly
616  *	constructed (always have ..'s, directories have links)
617  */
618 Char   *
619 dcanon(cp, p)
620     register Char *cp, *p;
621 {
622     register Char *sp;
623     register Char *p1, *p2;	/* general purpose */
624     bool    slash;
625 
626     Char    link[MAXPATHLEN];
627     char    tlink[MAXPATHLEN];
628     int     cc;
629     Char   *newcp;
630 
631     /*
632      * christos: if the path given does not start with a slash prepend cwd. If
633      * cwd does not start with a path or the result would be too long abort().
634      */
635     if (*cp != '/') {
636 	Char    tmpdir[MAXPATHLEN];
637 
638 	p1 = value(STRcwd);
639 	if (p1 == NULL || *p1 != '/')
640 	    abort();
641 	if (Strlen(p1) + Strlen(cp) + 1 >= MAXPATHLEN)
642 	    abort();
643 	(void) Strcpy(tmpdir, p1);
644 	(void) Strcat(tmpdir, STRslash);
645 	(void) Strcat(tmpdir, cp);
646 	xfree((ptr_t) cp);
647 	cp = p = Strsave(tmpdir);
648     }
649 
650     while (*p) {		/* for each component */
651 	sp = p;			/* save slash address */
652 	while (*++p == '/')	/* flush extra slashes */
653 	    ;
654 	if (p != ++sp)
655 	    for (p1 = sp, p2 = p; *p1++ = *p2++;);
656 	p = sp;			/* save start of component */
657 	slash = 0;
658 	while (*++p)		/* find next slash or end of path */
659 	    if (*p == '/') {
660 		slash = 1;
661 		*p = 0;
662 		break;
663 	    }
664 
665 	if (*sp == '\0')	/* if component is null */
666 	    if (--sp == cp)	/* if path is one char (i.e. /) */
667 		break;
668 	    else
669 		*sp = '\0';
670 	else if (sp[0] == '.' && sp[1] == 0) {
671 	    if (slash) {
672 		for (p1 = sp, p2 = p + 1; *p1++ = *p2++;);
673 		p = --sp;
674 	    }
675 	    else if (--sp != cp)
676 		*sp = '\0';
677 	}
678 	else if (sp[0] == '.' && sp[1] == '.' && sp[2] == 0) {
679 	    /*
680 	     * We have something like "yyy/xxx/..", where "yyy" can be null or
681 	     * a path starting at /, and "xxx" is a single component. Before
682 	     * compressing "xxx/..", we want to expand "yyy/xxx", if it is a
683 	     * symbolic link.
684 	     */
685 	    *--sp = 0;		/* form the pathname for readlink */
686 	    if (sp != cp && !adrof(STRignore_symlinks) &&
687 		(cc = readlink(short2str(cp), tlink,
688 			       sizeof tlink)) >= 0) {
689 		(void) Strcpy(link, str2short(tlink));
690 		link[cc] = '\0';
691 
692 		if (slash)
693 		    *p = '/';
694 		/*
695 		 * Point p to the '/' in "/..", and restore the '/'.
696 		 */
697 		*(p = sp) = '/';
698 		/*
699 		 * find length of p
700 		 */
701 		for (p1 = p; *p1++;);
702 		if (*link != '/') {
703 		    /*
704 		     * Relative path, expand it between the "yyy/" and the
705 		     * "/..". First, back sp up to the character past "yyy/".
706 		     */
707 		    while (*--sp != '/');
708 		    sp++;
709 		    *sp = 0;
710 		    /*
711 		     * New length is "yyy/" + link + "/.." and rest
712 		     */
713 		    p1 = newcp = (Char *) xmalloc((size_t)
714 						(((sp - cp) + cc + (p1 - p)) *
715 						 sizeof(Char)));
716 		    /*
717 		     * Copy new path into newcp
718 		     */
719 		    for (p2 = cp; *p1++ = *p2++;);
720 		    for (p1--, p2 = link; *p1++ = *p2++;);
721 		    for (p1--, p2 = p; *p1++ = *p2++;);
722 		    /*
723 		     * Restart canonicalization at expanded "/xxx".
724 		     */
725 		    p = sp - cp - 1 + newcp;
726 		}
727 		else {
728 		    /*
729 		     * New length is link + "/.." and rest
730 		     */
731 		    p1 = newcp = (Char *) xmalloc((size_t)
732 					    ((cc + (p1 - p)) * sizeof(Char)));
733 		    /*
734 		     * Copy new path into newcp
735 		     */
736 		    for (p2 = link; *p1++ = *p2++;);
737 		    for (p1--, p2 = p; *p1++ = *p2++;);
738 		    /*
739 		     * Restart canonicalization at beginning
740 		     */
741 		    p = newcp;
742 		}
743 		xfree((ptr_t) cp);
744 		cp = newcp;
745 		continue;	/* canonicalize the link */
746 	    }
747 	    *sp = '/';
748 	    if (sp != cp)
749 		while (*--sp != '/');
750 	    if (slash) {
751 		for (p1 = sp + 1, p2 = p + 1; *p1++ = *p2++;);
752 		p = sp;
753 	    }
754 	    else if (cp == sp)
755 		*++sp = '\0';
756 	    else
757 		*sp = '\0';
758 	}
759 	else {			/* normal dir name (not . or .. or nothing) */
760 
761 	    if (sp != cp && adrof(STRchase_symlinks) &&
762 		!adrof(STRignore_symlinks) &&
763 		(cc = readlink(short2str(cp), tlink,
764 			       sizeof tlink)) >= 0) {
765 		(void) Strcpy(link, str2short(tlink));
766 		link[cc] = '\0';
767 
768 		/*
769 		 * restore the '/'.
770 		 */
771 		if (slash)
772 		    *p = '/';
773 
774 		/*
775 		 * point sp to p (rather than backing up).
776 		 */
777 		sp = p;
778 
779 		/*
780 		 * find length of p
781 		 */
782 		for (p1 = p; *p1++;);
783 		if (*link != '/') {
784 		    /*
785 		     * Relative path, expand it between the "yyy/" and the
786 		     * remainder. First, back sp up to the character past
787 		     * "yyy/".
788 		     */
789 		    while (*--sp != '/');
790 		    sp++;
791 		    *sp = 0;
792 		    /*
793 		     * New length is "yyy/" + link + "/.." and rest
794 		     */
795 		    p1 = newcp = (Char *) xmalloc((size_t)
796 						  (((sp - cp) + cc + (p1 - p))
797 						   * sizeof(Char)));
798 		    /*
799 		     * Copy new path into newcp
800 		     */
801 		    for (p2 = cp; *p1++ = *p2++;);
802 		    for (p1--, p2 = link; *p1++ = *p2++;);
803 		    for (p1--, p2 = p; *p1++ = *p2++;);
804 		    /*
805 		     * Restart canonicalization at expanded "/xxx".
806 		     */
807 		    p = sp - cp - 1 + newcp;
808 		}
809 		else {
810 		    /*
811 		     * New length is link + the rest
812 		     */
813 		    p1 = newcp = (Char *) xmalloc((size_t)
814 					    ((cc + (p1 - p)) * sizeof(Char)));
815 		    /*
816 		     * Copy new path into newcp
817 		     */
818 		    for (p2 = link; *p1++ = *p2++;);
819 		    for (p1--, p2 = p; *p1++ = *p2++;);
820 		    /*
821 		     * Restart canonicalization at beginning
822 		     */
823 		    p = newcp;
824 		}
825 		xfree((ptr_t) cp);
826 		cp = newcp;
827 		continue;	/* canonicalize the link */
828 	    }
829 	    if (slash)
830 		*p = '/';
831 	}
832     }
833 
834     /*
835      * fix home...
836      */
837     p1 = value(STRhome);
838     cc = Strlen(p1);
839     /*
840      * See if we're not in a subdir of STRhome
841      */
842     if (p1 && *p1 == '/' &&
843 	(Strncmp(p1, cp, cc) != 0 || (cp[cc] != '/' && cp[cc] != '\0'))) {
844 	static ino_t home_ino = -1;
845 	static dev_t home_dev = -1;
846 	static Char *home_ptr = NULL;
847 	struct stat statbuf;
848 
849 	/*
850 	 * Get dev and ino of STRhome
851 	 */
852 	if (home_ptr != p1 &&
853 	    stat(short2str(p1), &statbuf) != -1) {
854 	    home_dev = statbuf.st_dev;
855 	    home_ino = statbuf.st_ino;
856 	    home_ptr = p1;
857 	}
858 	/*
859 	 * Start comparing dev & ino backwards
860 	 */
861 	p2 = Strcpy(link, cp);
862 	for (sp = NULL; *p2 && stat(short2str(p2), &statbuf) != -1;) {
863 	    if (statbuf.st_dev == home_dev &&
864 		statbuf.st_ino == home_ino) {
865 		sp = (Char *) - 1;
866 		break;
867 	    }
868 	    if (sp = Strrchr(p2, '/'))
869 		*sp = '\0';
870 	}
871 	/*
872 	 * See if we found it
873 	 */
874 	if (*p2 && sp == (Char *) -1) {
875 	    /*
876 	     * Use STRhome to make '~' work
877 	     */
878 	    p2 = cp + Strlen(p2);
879 	    sp = newcp = (Char *) xmalloc((size_t)
880 /* 19 Sep 92*/			  ((cc + Strlen(p2) + 1) * sizeof(Char)));
881 	    while (*p1)
882 		*sp++ = *p1++;
883 	    while (*p2)
884 		*sp++ = *p2++;
885 	    *sp = '\0';
886 	    xfree((ptr_t) cp);
887 	    cp = newcp;
888 	}
889     }
890     return cp;
891 }
892 
893 
894 /*
895  * dnewcwd - make a new directory in the loop the current one
896  */
897 static void
898 dnewcwd(dp)
899     register struct directory *dp;
900 {
901     dcwd = dp;
902     dset(dcwd->di_name);
903     if (printd && !(adrof(STRpushdsilent)))
904 	printdirs();
905 }
906