xref: /netbsd-src/bin/csh/dir.c (revision 220b5c059a84c51ea44107ea8951a57ffaecdc8c)
1 /* $NetBSD: dir.c,v 1.18 2001/11/03 13:35:39 lukem Exp $ */
2 
3 /*-
4  * Copyright (c) 1980, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #ifndef lint
38 #if 0
39 static char sccsid[] = "@(#)dir.c	8.1 (Berkeley) 5/31/93";
40 #else
41 __RCSID("$NetBSD: dir.c,v 1.18 2001/11/03 13:35:39 lukem Exp $");
42 #endif
43 #endif /* not lint */
44 
45 #include <sys/param.h>
46 #include <sys/stat.h>
47 
48 #include <errno.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <unistd.h>
52 
53 #if __STDC__
54 # include <stdarg.h>
55 #else
56 # include <varargs.h>
57 #endif
58 
59 #include "csh.h"
60 #include "dir.h"
61 #include "extern.h"
62 
63 /* Directory management. */
64 
65 static struct directory *dfind(Char *);
66 static Char *dfollow(Char *);
67 static void printdirs(void);
68 static Char *dgoto(Char *);
69 static void skipargs(Char ***, char *);
70 static void dnewcwd(struct directory *);
71 static void dset(Char *);
72 
73 struct directory dhead;		/* "head" of loop */
74 int printd;			/* force name to be printed */
75 
76 static int dirflag = 0;
77 
78 /*
79  * dinit - initialize current working directory
80  */
81 void
82 dinit(Char *hp)
83 {
84     static const char emsg[] = "csh: Trying to start from \"%s\"\n";
85     char path[MAXPATHLEN];
86     struct directory *dp;
87     const char *ecp;
88     Char *cp;
89 
90     /* Don't believe the login shell home, because it may be a symlink */
91     ecp = getcwd(path, MAXPATHLEN);
92     if (ecp == NULL || *ecp == '\0') {
93 	(void)fprintf(csherr, "csh: %s\n", strerror(errno));
94 	if (hp && *hp) {
95 	    ecp = short2str(hp);
96 	    if (chdir(ecp) == -1)
97 		cp = NULL;
98 	    else
99 		cp = hp;
100 	    (void)fprintf(csherr, emsg, vis_str(hp));
101 	}
102 	else
103 	    cp = NULL;
104 	if (cp == NULL) {
105 	    (void)fprintf(csherr, emsg, "/");
106 	    if (chdir("/") == -1) {
107 		/* I am not even try to print an error message! */
108 		xexit(1);
109 	    }
110 	    cp = SAVE("/");
111 	}
112     }
113     else {
114 	struct stat swd, shp;
115 
116 	/*
117 	 * See if $HOME is the working directory we got and use that
118 	 */
119 	if (hp && *hp &&
120 	    stat(ecp, &swd) != -1 && stat(short2str(hp), &shp) != -1 &&
121 	    swd.st_dev == shp.st_dev && swd.st_ino == shp.st_ino)
122 	    cp = hp;
123 	else {
124 	    const char *cwd;
125 
126 	    /*
127 	     * use PWD if we have it (for subshells)
128 	     */
129 	    if ((cwd = getenv("PWD")) != NULL) {
130 		if (stat(cwd, &shp) != -1 && swd.st_dev == shp.st_dev &&
131 		    swd.st_ino == shp.st_ino)
132 		    ecp = cwd;
133 	    }
134 	    cp = dcanon(SAVE(ecp), STRNULL);
135 	}
136     }
137 
138     dp = (struct directory *)xcalloc(sizeof(struct directory), 1);
139     dp->di_name = Strsave(cp);
140     dp->di_count = 0;
141     dhead.di_next = dhead.di_prev = dp;
142     dp->di_next = dp->di_prev = &dhead;
143     printd = 0;
144     dnewcwd(dp);
145 }
146 
147 static void
148 dset(Char *dp)
149 {
150     Char **vec;
151 
152     /*
153      * Don't call set() directly cause if the directory contains ` or
154      * other junk characters glob will fail.
155      */
156 
157     vec = (Char **)xmalloc((size_t)(2 * sizeof(Char **)));
158     vec[0] = Strsave(dp);
159     vec[1] = 0;
160     setq(STRcwd, vec, &shvhed);
161     Setenv(STRPWD, dp);
162 }
163 
164 #define DIR_LONG 1
165 #define DIR_VERT 2
166 #define DIR_LINE 4
167 
168 static void
169 skipargs(Char ***v, char *str)
170 {
171     Char  **n, *s;
172 
173     n = *v;
174     dirflag = 0;
175     for (n++; *n != NULL && (*n)[0] == '-'; n++)
176 	for (s = &((*n)[1]); *s; s++)
177 	    switch (*s) {
178 	    case 'l':
179 		dirflag |= DIR_LONG;
180 		break;
181 	    case 'n':
182 		dirflag |= DIR_LINE;
183 		break;
184 	    case 'v':
185 		dirflag |= DIR_VERT;
186 		break;
187 	    default:
188 		stderror(ERR_DIRUS, vis_str(**v), str);
189 		/* NOTREACHED */
190 	    }
191     *v = n;
192 }
193 
194 /*
195  * dodirs - list all directories in directory loop
196  */
197 void
198 /*ARGSUSED*/
199 dodirs(Char **v, struct command *t)
200 {
201     skipargs(&v, "");
202 
203     if (*v != NULL)
204 	stderror(ERR_DIRUS, "dirs", "");
205     printdirs();
206 }
207 
208 static void
209 printdirs(void)
210 {
211     struct directory *dp;
212     Char *hp, *s;
213     int cur, idx, len;
214 
215     hp = value(STRhome);
216     if (*hp == '\0')
217 	hp = NULL;
218     dp = dcwd;
219     idx = 0;
220     cur = 0;
221     do {
222 	if (dp == &dhead)
223 	    continue;
224 	if (dirflag & DIR_VERT) {
225 	    (void)fprintf(cshout, "%d\t", idx++);
226 	    cur = 0;
227 	}
228 	if (!(dirflag & DIR_LONG) && hp != NULL && !eq(hp, STRslash) &&
229 	    (len = Strlen(hp), Strncmp(hp, dp->di_name, len) == 0) &&
230 	    (dp->di_name[len] == '\0' || dp->di_name[len] == '/'))
231 	    len = Strlen(s = (dp->di_name + len)) + 2;
232 	else
233 	    len = Strlen(s = dp->di_name) + 1;
234 
235 	cur += len;
236 	if ((dirflag & DIR_LINE) && cur >= 80 - 1 && len < 80) {
237 	    (void)fprintf(cshout, "\n");
238 	    cur = len;
239 	}
240 	(void) fprintf(cshout, "%s%s%c", (s != dp->di_name)? "~" : "",
241 	    vis_str(s), (dirflag & DIR_VERT) ? '\n' : ' ');
242     } while ((dp = dp->di_prev) != dcwd);
243     if (!(dirflag & DIR_VERT))
244 	(void)fprintf(cshout, "\n");
245 }
246 
247 void
248 dtildepr(Char *home, Char *dir)
249 {
250     if (!eq(home, STRslash) && prefix(home, dir))
251 	(void)fprintf(cshout, "~%s", vis_str(dir + Strlen(home)));
252     else
253 	(void)fprintf(cshout, "%s", vis_str(dir));
254 }
255 
256 void
257 dtilde(void)
258 {
259     struct directory *d;
260 
261     d = dcwd;
262     do {
263 	if (d == &dhead)
264 	    continue;
265 	d->di_name = dcanon(d->di_name, STRNULL);
266     } while ((d = d->di_prev) != dcwd);
267 
268     dset(dcwd->di_name);
269 }
270 
271 
272 /* dnormalize():
273  *	If the name starts with . or .. then we might need to normalize
274  *	it depending on the symbolic link flags
275  */
276 Char *
277 dnormalize(Char *cp)
278 {
279 #define UC (unsigned char)
280 #define ISDOT(c) (UC(c)[0] == '.' && ((UC(c)[1] == '\0') || (UC(c)[1] == '/')))
281 #define ISDOTDOT(c) (UC(c)[0] == '.' && ISDOT(&((c)[1])))
282     if ((unsigned char) cp[0] == '/')
283 	return (Strsave(cp));
284 
285     if (adrof(STRignore_symlinks)) {
286 	int     dotdot = 0;
287 	Char   *dp, *cwd;
288 
289 	cwd = (Char *)xmalloc((size_t)((Strlen(dcwd->di_name) + 3) *
290 	    sizeof(Char)));
291 	(void)Strcpy(cwd, dcwd->di_name);
292 
293 	/*
294 	 * Ignore . and count ..'s
295 	 */
296 	while (*cp) {
297 	    if (ISDOT(cp)) {
298 		if (*++cp)
299 		    cp++;
300 	    }
301 	    else if (ISDOTDOT(cp)) {
302 		dotdot++;
303 		cp += 2;
304 		if (*cp)
305 		    cp++;
306 	    }
307 	    else
308 		break;
309 	}
310 	while (dotdot > 0) {
311 	    dp = Strrchr(cwd, '/');
312 	    if (dp) {
313 		*dp = '\0';
314 		dotdot--;
315 	    }
316 	    else
317 		break;
318 	}
319 
320 	if (*cp) {
321 	    cwd[dotdot = Strlen(cwd)] = '/';
322 	    cwd[dotdot + 1] = '\0';
323 	    dp = Strspl(cwd, cp);
324 	    xfree((ptr_t) cwd);
325 	    return dp;
326 	}
327 	else {
328 	    if (!*cwd) {
329 		cwd[0] = '/';
330 		cwd[1] = '\0';
331 	    }
332 	    return cwd;
333 	}
334     }
335     return Strsave(cp);
336 }
337 
338 /*
339  * dochngd - implement chdir command.
340  */
341 void
342 /*ARGSUSED*/
343 dochngd(Char **v, struct command *t)
344 {
345     struct directory *dp;
346     Char *cp;
347 
348     skipargs(&v, " [<dir>]");
349     printd = 0;
350     if (*v == NULL) {
351 	if ((cp = value(STRhome)) == NULL || *cp == 0)
352 	    stderror(ERR_NAME | ERR_NOHOMEDIR);
353 	if (chdir(short2str(cp)) < 0)
354 	    stderror(ERR_NAME | ERR_CANTCHANGE);
355 	cp = Strsave(cp);
356     }
357     else if (v[1] != NULL)
358 	stderror(ERR_NAME | ERR_TOOMANY);
359     else if ((dp = dfind(*v)) != 0) {
360 	char   *tmp;
361 
362 	printd = 1;
363 	if (chdir(tmp = short2str(dp->di_name)) < 0)
364 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
365 	dcwd->di_prev->di_next = dcwd->di_next;
366 	dcwd->di_next->di_prev = dcwd->di_prev;
367 	dfree(dcwd);
368 	dnewcwd(dp);
369 	return;
370     }
371     else
372 	cp = dfollow(*v);
373     dp = (struct directory *)xcalloc(sizeof(struct directory), 1);
374     dp->di_name = cp;
375     dp->di_count = 0;
376     dp->di_next = dcwd->di_next;
377     dp->di_prev = dcwd->di_prev;
378     dp->di_prev->di_next = dp;
379     dp->di_next->di_prev = dp;
380     dfree(dcwd);
381     dnewcwd(dp);
382 }
383 
384 static Char *
385 dgoto(Char *cp)
386 {
387     Char *dp;
388 
389     if (*cp != '/') {
390 	Char *p, *q;
391 	int cwdlen;
392 
393 	for (p = dcwd->di_name; *p++;)
394 	    continue;
395 	if ((cwdlen = p - dcwd->di_name - 1) == 1)	/* root */
396 	    cwdlen = 0;
397 	for (p = cp; *p++;)
398 	    continue;
399 	dp = (Char *)xmalloc((size_t)((cwdlen + (p - cp) + 1) * sizeof(Char)));
400 	for (p = dp, q = dcwd->di_name; (*p++ = *q++) != '\0';)
401 	    continue;
402 	if (cwdlen)
403 	    p[-1] = '/';
404 	else
405 	    p--;		/* don't add a / after root */
406 	for (q = cp; (*p++ = *q++) != '\0';)
407 	    continue;
408 	xfree((ptr_t) cp);
409 	cp = dp;
410 	dp += cwdlen;
411     }
412     else
413 	dp = cp;
414 
415     cp = dcanon(cp, dp);
416     return cp;
417 }
418 
419 /*
420  * dfollow - change to arg directory; fall back on cdpath if not valid
421  */
422 static Char *
423 dfollow(Char *cp)
424 {
425     char ebuf[MAXPATHLEN];
426     struct varent *c;
427     Char *dp;
428     int serrno;
429 
430     cp = globone(cp, G_ERROR);
431     /*
432      * if we are ignoring symlinks, try to fix relatives now.
433      */
434     dp = dnormalize(cp);
435     if (chdir(short2str(dp)) >= 0) {
436 	xfree((ptr_t) cp);
437 	return dgoto(dp);
438     }
439     else {
440 	xfree((ptr_t) dp);
441 	if (chdir(short2str(cp)) >= 0)
442 	    return dgoto(cp);
443 	serrno = errno;
444     }
445 
446     if (cp[0] != '/' && !prefix(STRdotsl, cp) && !prefix(STRdotdotsl, cp)
447 	&& (c = adrof(STRcdpath))) {
448 	Char  **cdp;
449 	Char *p;
450 	Char    buf[MAXPATHLEN];
451 
452 	for (cdp = c->vec; *cdp; cdp++) {
453 	    for (dp = buf, p = *cdp; (*dp++ = *p++) != '\0';)
454 		continue;
455 	    dp[-1] = '/';
456 	    for (p = cp; (*dp++ = *p++) != '\0';)
457 		continue;
458 	    if (chdir(short2str(buf)) >= 0) {
459 		printd = 1;
460 		xfree((ptr_t) cp);
461 		cp = Strsave(buf);
462 		return dgoto(cp);
463 	    }
464 	}
465     }
466     dp = value(cp);
467     if ((dp[0] == '/' || dp[0] == '.') && chdir(short2str(dp)) >= 0) {
468 	xfree((ptr_t) cp);
469 	cp = Strsave(dp);
470 	printd = 1;
471 	return dgoto(cp);
472     }
473     (void)strcpy(ebuf, short2str(cp));
474     xfree((ptr_t) cp);
475     stderror(ERR_SYSTEM, ebuf, strerror(serrno));
476     /* NOTREACHED */
477 }
478 
479 /*
480  * dopushd - push new directory onto directory stack.
481  *	with no arguments exchange top and second.
482  *	with numeric argument (+n) bring it to top.
483  */
484 void
485 /*ARGSUSED*/
486 dopushd(Char **v, struct command *t)
487 {
488     struct directory *dp;
489 
490     skipargs(&v, " [<dir>|+<n>]");
491     printd = 1;
492     if (*v == NULL) {
493 	char   *tmp;
494 
495 	if ((dp = dcwd->di_prev) == &dhead)
496 	    dp = dhead.di_prev;
497 	if (dp == dcwd)
498 	    stderror(ERR_NAME | ERR_NODIR);
499 	if (chdir(tmp = short2str(dp->di_name)) < 0)
500 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
501 	dp->di_prev->di_next = dp->di_next;
502 	dp->di_next->di_prev = dp->di_prev;
503 	dp->di_next = dcwd->di_next;
504 	dp->di_prev = dcwd;
505 	dcwd->di_next->di_prev = dp;
506 	dcwd->di_next = dp;
507     }
508     else if (v[1] != NULL)
509 	stderror(ERR_NAME | ERR_TOOMANY);
510     else if ((dp = dfind(*v)) != NULL) {
511 	char   *tmp;
512 
513 	if (chdir(tmp = short2str(dp->di_name)) < 0)
514 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
515     }
516     else {
517 	Char *ccp;
518 
519 	ccp = dfollow(*v);
520 	dp = (struct directory *)xcalloc(sizeof(struct directory), 1);
521 	dp->di_name = ccp;
522 	dp->di_count = 0;
523 	dp->di_prev = dcwd;
524 	dp->di_next = dcwd->di_next;
525 	dcwd->di_next = dp;
526 	dp->di_next->di_prev = dp;
527     }
528     dnewcwd(dp);
529 }
530 
531 /*
532  * dfind - find a directory if specified by numeric (+n) argument
533  */
534 static struct directory *
535 dfind(Char *cp)
536 {
537     struct directory *dp;
538     Char *ep;
539     int i;
540 
541     if (*cp++ != '+')
542 	return (0);
543     for (ep = cp; Isdigit(*ep); ep++)
544 	continue;
545     if (*ep)
546 	return (0);
547     i = getn(cp);
548     if (i <= 0)
549 	return (0);
550     for (dp = dcwd; i != 0; i--) {
551 	if ((dp = dp->di_prev) == &dhead)
552 	    dp = dp->di_prev;
553 	if (dp == dcwd)
554 	    stderror(ERR_NAME | ERR_DEEP);
555     }
556     return (dp);
557 }
558 
559 /*
560  * dopopd - pop a directory out of the directory stack
561  *	with a numeric argument just discard it.
562  */
563 void
564 /*ARGSUSED*/
565 dopopd(Char **v, struct command *t)
566 {
567     struct directory *dp, *p = NULL;
568 
569     skipargs(&v, " [+<n>]");
570     printd = 1;
571     if (*v == NULL)
572 	dp = dcwd;
573     else if (v[1] != NULL)
574 	stderror(ERR_NAME | ERR_TOOMANY);
575     else if ((dp = dfind(*v)) == 0)
576 	stderror(ERR_NAME | ERR_BADDIR);
577     if (dp->di_prev == &dhead && dp->di_next == &dhead)
578 	stderror(ERR_NAME | ERR_EMPTY);
579     if (dp == dcwd) {
580 	char *tmp;
581 
582 	if ((p = dp->di_prev) == &dhead)
583 	    p = dhead.di_prev;
584 	if (chdir(tmp = short2str(p->di_name)) < 0)
585 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
586     }
587     dp->di_prev->di_next = dp->di_next;
588     dp->di_next->di_prev = dp->di_prev;
589     if (dp == dcwd)
590 	dnewcwd(p);
591     else {
592 	printdirs();
593     }
594     dfree(dp);
595 }
596 
597 /*
598  * dfree - free the directory (or keep it if it still has ref count)
599  */
600 void
601 dfree(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(Char *cp, Char *p)
620 {
621     Char slink[MAXPATHLEN];
622     char tlink[MAXPATHLEN];
623     Char *newcp, *sp;
624     Char *p1, *p2;	/* general purpose */
625     int cc;
626     bool slash;
627 
628     /*
629      * christos: if the path given does not start with a slash prepend cwd. If
630      * cwd does not start with a path or the result would be too long abort().
631      */
632     if (*cp != '/') {
633 	Char tmpdir[MAXPATHLEN];
634 
635 	p1 = value(STRcwd);
636 	if (p1 == NULL || *p1 != '/')
637 	    abort();
638 	if (Strlen(p1) + Strlen(cp) + 1 >= MAXPATHLEN)
639 	    abort();
640 	(void)Strcpy(tmpdir, p1);
641 	(void)Strcat(tmpdir, STRslash);
642 	(void)Strcat(tmpdir, cp);
643 	xfree((ptr_t) cp);
644 	cp = p = Strsave(tmpdir);
645     }
646 
647     while (*p) {		/* for each component */
648 	sp = p;			/* save slash address */
649 	while (*++p == '/')	/* flush extra slashes */
650 	    continue;
651 	if (p != ++sp)
652 	    for (p1 = sp, p2 = p; (*p1++ = *p2++) != '\0';)
653 		continue;
654 	p = sp;			/* save start of component */
655 	slash = 0;
656 	while (*++p)		/* find next slash or end of path */
657 	    if (*p == '/') {
658 		slash = 1;
659 		*p = 0;
660 		break;
661 	    }
662 
663 	if (*sp == '\0') {	/* if component is null */
664 	    if (--sp == cp)	/* if path is one char (i.e. /) */
665 		break;
666 	    else
667 		*sp = '\0';
668 	} else if (sp[0] == '.' && sp[1] == 0) {
669 	    if (slash) {
670 		for (p1 = sp, p2 = p + 1; (*p1++ = *p2++) != '\0';)
671 		    continue;
672 		p = --sp;
673 	    }
674 	    else if (--sp != cp)
675 		*sp = '\0';
676 	}
677 	else if (sp[0] == '.' && sp[1] == '.' && sp[2] == 0) {
678 	    /*
679 	     * We have something like "yyy/xxx/..", where "yyy" can be null or
680 	     * a path starting at /, and "xxx" is a single component. Before
681 	     * compressing "xxx/..", we want to expand "yyy/xxx", if it is a
682 	     * symbolic link.
683 	     */
684 	    *--sp = 0;		/* form the pathname for readlink */
685 	    if (sp != cp && !adrof(STRignore_symlinks) &&
686 		(cc = readlink(short2str(cp), tlink,
687 			       sizeof tlink)) >= 0) {
688 		(void)Strcpy(slink, str2short(tlink));
689 		slink[cc] = '\0';
690 
691 		if (slash)
692 		    *p = '/';
693 		/*
694 		 * Point p to the '/' in "/..", and restore the '/'.
695 		 */
696 		*(p = sp) = '/';
697 		/*
698 		 * find length of p
699 		 */
700 		for (p1 = p; *p1++;)
701 		    continue;
702 		if (*slink != '/') {
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 			continue;
709 		    sp++;
710 		    *sp = 0;
711 		    /*
712 		     * New length is "yyy/" + slink + "/.." and rest
713 		     */
714 		    p1 = newcp = (Char *)xmalloc(
715 		        (size_t)(((sp - cp) + cc + (p1 - p)) * sizeof(Char)));
716 		    /*
717 		     * Copy new path into newcp
718 		     */
719 		    for (p2 = cp; (*p1++ = *p2++) != '\0';)
720 			continue;
721 		    for (p1--, p2 = slink; (*p1++ = *p2++) != '\0';)
722 			continue;
723 		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
724 			continue;
725 		    /*
726 		     * Restart canonicalization at expanded "/xxx".
727 		     */
728 		    p = sp - cp - 1 + newcp;
729 		}
730 		else {
731 		    /*
732 		     * New length is slink + "/.." and rest
733 		     */
734 		    p1 = newcp = (Char *)xmalloc(
735 		        (size_t)((cc + (p1 - p)) * sizeof(Char)));
736 		    /*
737 		     * Copy new path into newcp
738 		     */
739 		    for (p2 = slink; (*p1++ = *p2++) != '\0';)
740 			continue;
741 		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
742 			continue;
743 		    /*
744 		     * Restart canonicalization at beginning
745 		     */
746 		    p = newcp;
747 		}
748 		xfree((ptr_t) cp);
749 		cp = newcp;
750 		continue;	/* canonicalize the link */
751 	    }
752 	    *sp = '/';
753 	    if (sp != cp)
754 		while (*--sp != '/')
755 		    continue;
756 	    if (slash) {
757 		for (p1 = sp + 1, p2 = p + 1; (*p1++ = *p2++) != '\0';)
758 		    continue;
759 		p = sp;
760 	    }
761 	    else if (cp == sp)
762 		*++sp = '\0';
763 	    else
764 		*sp = '\0';
765 	}
766 	else {			/* normal dir name (not . or .. or nothing) */
767 
768 	    if (sp != cp && adrof(STRchase_symlinks) &&
769 		!adrof(STRignore_symlinks) &&
770 		(cc = readlink(short2str(cp), tlink, sizeof(tlink))) >= 0) {
771 		(void)Strcpy(slink, str2short(tlink));
772 		slink[cc] = '\0';
773 
774 		/*
775 		 * restore the '/'.
776 		 */
777 		if (slash)
778 		    *p = '/';
779 
780 		/*
781 		 * point sp to p (rather than backing up).
782 		 */
783 		sp = p;
784 
785 		/*
786 		 * find length of p
787 		 */
788 		for (p1 = p; *p1++;)
789 		    continue;
790 		if (*slink != '/') {
791 		    /*
792 		     * Relative path, expand it between the "yyy/" and the
793 		     * remainder. First, back sp up to the character past
794 		     * "yyy/".
795 		     */
796 		    while (*--sp != '/')
797 			continue;
798 		    sp++;
799 		    *sp = 0;
800 		    /*
801 		     * New length is "yyy/" + slink + "/.." and rest
802 		     */
803 		    p1 = newcp = (Char *)xmalloc(
804 		        (size_t)(((sp - cp) + cc + (p1 - p)) * sizeof(Char)));
805 		    /*
806 		     * Copy new path into newcp
807 		     */
808 		    for (p2 = cp; (*p1++ = *p2++) != '\0';)
809 			continue;
810 		    for (p1--, p2 = slink; (*p1++ = *p2++) != '\0';)
811 			continue;
812 		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
813 			continue;
814 		    /*
815 		     * Restart canonicalization at expanded "/xxx".
816 		     */
817 		    p = sp - cp - 1 + newcp;
818 		}
819 		else {
820 		    /*
821 		     * New length is slink + the rest
822 		     */
823 		    p1 = newcp = (Char *)xmalloc(
824 		        (size_t)((cc + (p1 - p)) * sizeof(Char)));
825 		    /*
826 		     * Copy new path into newcp
827 		     */
828 		    for (p2 = slink; (*p1++ = *p2++) != '\0';)
829 			continue;
830 		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
831 			continue;
832 		    /*
833 		     * Restart canonicalization at beginning
834 		     */
835 		    p = newcp;
836 		}
837 		xfree((ptr_t) cp);
838 		cp = newcp;
839 		continue;	/* canonicalize the link */
840 	    }
841 	    if (slash)
842 		*p = '/';
843 	}
844     }
845 
846     /*
847      * fix home...
848      */
849     p1 = value(STRhome);
850     cc = Strlen(p1);
851     /*
852      * See if we're not in a subdir of STRhome
853      */
854     if (p1 && *p1 == '/' &&
855 	(Strncmp(p1, cp, cc) != 0 || (cp[cc] != '/' && cp[cc] != '\0'))) {
856 	static ino_t home_ino;
857 	static dev_t home_dev = NODEV;
858 	static Char *home_ptr = NULL;
859 	struct stat statbuf;
860 
861 	/*
862 	 * Get dev and ino of STRhome
863 	 */
864 	if (home_ptr != p1 &&
865 	    stat(short2str(p1), &statbuf) != -1) {
866 	    home_dev = statbuf.st_dev;
867 	    home_ino = statbuf.st_ino;
868 	    home_ptr = p1;
869 	}
870 	/*
871 	 * Start comparing dev & ino backwards
872 	 */
873 	p2 = Strcpy(slink, cp);
874 	for (sp = NULL; *p2 && stat(short2str(p2), &statbuf) != -1;) {
875 	    if (statbuf.st_dev == home_dev &&
876 		statbuf.st_ino == home_ino) {
877 		sp = (Char *) - 1;
878 		break;
879 	    }
880 	    if ((sp = Strrchr(p2, '/')) != NULL)
881 		*sp = '\0';
882 	}
883 	/*
884 	 * See if we found it
885 	 */
886 	if (*p2 && sp == (Char *) -1) {
887 	    /*
888 	     * Use STRhome to make '~' work
889 	     */
890 	    newcp = Strspl(p1, cp + Strlen(p2));
891 	    xfree((ptr_t) cp);
892 	    cp = newcp;
893 	}
894     }
895     return cp;
896 }
897 
898 
899 /*
900  * dnewcwd - make a new directory in the loop the current one
901  */
902 static void
903 dnewcwd(struct directory *dp)
904 {
905     dcwd = dp;
906     dset(dcwd->di_name);
907     if (printd && !(adrof(STRpushdsilent)))
908 	printdirs();
909 }
910