1 /*-
2  * Copyright (c) 1980, 1991, 1993
3  *	The Regents of the University of California.  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 #if 0
36 static char sccsid[] = "@(#)dir.c	8.1 (Berkeley) 5/31/93";
37 #else
38 static const char rcsid[] =
39   "$FreeBSD$";
40 #endif
41 #endif /* not lint */
42 
43 #include <sys/param.h>
44 #include <sys/stat.h>
45 #include <errno.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 #if __STDC__
50 # include <stdarg.h>
51 #else
52 # include <varargs.h>
53 #endif
54 
55 #include "csh.h"
56 #include "dir.h"
57 #include "extern.h"
58 
59 /* Directory management. */
60 
61 static struct directory
62 		*dfind __P((Char *));
63 static Char	*dfollow __P((Char *));
64 static void	 printdirs __P((void));
65 static Char	*dgoto __P((Char *));
66 static void	 dnewcwd __P((struct directory *));
67 static void	 dset __P((Char *));
68 
69 struct directory dhead;		/* "head" of loop */
70 int     printd;			/* force name to be printed */
71 
72 static int dirflag = 0;
73 
74 /*
75  * dinit - initialize current working directory
76  */
77 void
dinit(hp)78 dinit(hp)
79     Char   *hp;
80 {
81     char *tcp;
82     Char *cp;
83     struct directory *dp;
84     char    path[MAXPATHLEN];
85     static char *emsg = "csh: Trying to start from \"%s\"\n";
86 
87     /* Don't believe the login shell home, because it may be a symlink */
88     tcp = getcwd(path, MAXPATHLEN);	/* see ngetwd.c for System V version */
89     if (tcp == NULL || *tcp == '\0') {
90 	(void) fprintf(csherr, "csh: %s: %s\n", path, strerror(errno));
91 	if (hp && *hp) {
92 	    tcp = short2str(hp);
93 	    if (chdir(tcp) == -1)
94 		cp = NULL;
95 	    else
96 		cp = hp;
97 	    (void) fprintf(csherr, emsg, vis_str(hp));
98 	}
99 	else
100 	    cp = NULL;
101 	if (cp == NULL) {
102 	    (void) fprintf(csherr, emsg, "/");
103 	    if (chdir("/") == -1)
104 		/* I am not even try to print an error message! */
105 		xexit(1);
106 	    cp = SAVE("/");
107 	}
108     }
109     else {
110 	struct stat swd, shp;
111 
112 	/*
113 	 * See if $HOME is the working directory we got and use that
114 	 */
115 	if (hp && *hp &&
116 	    stat(tcp, &swd) != -1 && stat(short2str(hp), &shp) != -1 &&
117 	    swd.st_dev == shp.st_dev && swd.st_ino == shp.st_ino)
118 	    cp = hp;
119 	else {
120 	    char   *cwd;
121 
122 	    /*
123 	     * use PWD if we have it (for subshells)
124 	     */
125 	    if ((cwd = getenv("PWD")) != NULL) {
126 		if (stat(cwd, &shp) != -1 && swd.st_dev == shp.st_dev &&
127 		    swd.st_ino == shp.st_ino)
128 		    tcp = cwd;
129 	    }
130 	    cp = dcanon(SAVE(tcp), STRNULL);
131 	}
132     }
133 
134     dp = (struct directory *) xcalloc(sizeof(struct directory), 1);
135     dp->di_name = Strsave(cp);
136     dp->di_count = 0;
137     dhead.di_next = dhead.di_prev = dp;
138     dp->di_next = dp->di_prev = &dhead;
139     printd = 0;
140     dnewcwd(dp);
141 }
142 
143 static void
dset(dp)144 dset(dp)
145 Char *dp;
146 {
147     /*
148      * Don't call set() directly cause if the directory contains ` or
149      * other junk characters glob will fail.
150      */
151     Char **vec = (Char **) xmalloc((size_t) (2 * sizeof(Char **)));
152 
153     vec[0] = Strsave(dp);
154     vec[1] = 0;
155     setq(STRcwd, vec, &shvhed);
156     Setenv(STRPWD, dp);
157 }
158 
159 #define DIR_LONG 1
160 #define DIR_VERT 2
161 #define DIR_LINE 4
162 
163 static void
skipargs(v,str)164 skipargs(v, str)
165     Char ***v;
166     char   *str;
167 {
168     Char  **n = *v, *s;
169 
170     dirflag = 0;
171     for (n++; *n != NULL && (*n)[0] == '-'; n++)
172 	for (s = &((*n)[1]); *s; s++)
173 	    switch (*s) {
174 	    case 'l':
175 		dirflag |= DIR_LONG;
176 		break;
177 	    case 'v':
178 		dirflag |= DIR_VERT;
179 		break;
180 	    case 'n':
181 		dirflag |= DIR_LINE;
182 		break;
183 	    default:
184 		stderror(ERR_DIRUS, vis_str(**v), str);
185 		break;
186 	    }
187     *v = n;
188 }
189 
190 /*
191  * dodirs - list all directories in directory loop
192  */
193 void
194 /*ARGSUSED*/
dodirs(v,t)195 dodirs(v, t)
196     Char **v;
197     struct command *t;
198 {
199     skipargs(&v, "");
200 
201     if (*v != NULL)
202 	stderror(ERR_DIRUS, "dirs", "");
203     printdirs();
204 }
205 
206 static void
printdirs()207 printdirs()
208 {
209     struct directory *dp;
210     Char   *s, *hp = value(STRhome);
211     int     idx, len, cur;
212 
213     if (*hp == '\0')
214 	hp = NULL;
215     dp = dcwd;
216     idx = 0;
217     cur = 0;
218     do {
219 	if (dp == &dhead)
220 	    continue;
221 	if (dirflag & DIR_VERT) {
222 	    (void) fprintf(cshout, "%d\t", idx++);
223 	    cur = 0;
224 	}
225 	if (!(dirflag & DIR_LONG) && hp != NULL && !eq(hp, STRslash) &&
226 	    (len = Strlen(hp), Strncmp(hp, dp->di_name, len) == 0) &&
227 	    (dp->di_name[len] == '\0' || dp->di_name[len] == '/'))
228 	    len = Strlen(s = (dp->di_name + len)) + 2;
229 	else
230 	    len = Strlen(s = dp->di_name) + 1;
231 
232 	cur += len;
233 	if ((dirflag & DIR_LINE) && cur >= 80 - 1 && len < 80) {
234 	    (void) fprintf(cshout, "\n");
235 	    cur = len;
236 	}
237 	(void) fprintf(cshout, s != dp->di_name ? "~%s%c" : "%s%c",
238 		vis_str(s), (dirflag & DIR_VERT) ? '\n' : ' ');
239     } while ((dp = dp->di_prev) != dcwd);
240     if (!(dirflag & DIR_VERT))
241 	(void) fprintf(cshout, "\n");
242 }
243 
244 void
dtildepr(home,dir)245 dtildepr(home, dir)
246     Char *home, *dir;
247 {
248 
249     if (!eq(home, STRslash) && prefix(home, dir))
250 	(void) fprintf(cshout, "~%s", vis_str(dir + Strlen(home)));
251     else
252 	(void) fprintf(cshout, "%s", vis_str(dir));
253 }
254 
255 void
dtilde()256 dtilde()
257 {
258     struct directory *d = dcwd;
259 
260     do {
261 	if (d == &dhead)
262 	    continue;
263 	d->di_name = dcanon(d->di_name, STRNULL);
264     } while ((d = d->di_prev) != dcwd);
265 
266     dset(dcwd->di_name);
267 }
268 
269 
270 /* dnormalize():
271  *	If the name starts with . or .. then we might need to normalize
272  *	it depending on the symbolic link flags
273  */
274 Char   *
dnormalize(cp)275 dnormalize(cp)
276     Char   *cp;
277 {
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 
283     if ((unsigned char) cp[0] == '/')
284 	return (Strsave(cp));
285 
286     if (adrof(STRignore_symlinks)) {
287 	int     dotdot = 0;
288 	Char   *dp, *cwd;
289 
290 	cwd = (Char *) xmalloc((size_t) ((Strlen(dcwd->di_name) + 3) *
291 					 sizeof(Char)));
292 	(void) Strcpy(cwd, dcwd->di_name);
293 
294 	/*
295 	 * Ignore . and count ..'s
296 	 */
297 	while (*cp) {
298 	    if (ISDOT(cp)) {
299 		if (*++cp)
300 		    cp++;
301 	    }
302 	    else if (ISDOTDOT(cp)) {
303 		dotdot++;
304 		cp += 2;
305 		if (*cp)
306 		    cp++;
307 	    }
308 	    else
309 		break;
310 	}
311 	while (dotdot > 0)
312 	    if ((dp = Strrchr(cwd, '/'))) {
313 		*dp = '\0';
314 		dotdot--;
315 	    }
316 	    else
317 		break;
318 
319 	if (*cp) {
320 	    cwd[dotdot = Strlen(cwd)] = '/';
321 	    cwd[dotdot + 1] = '\0';
322 	    dp = Strspl(cwd, cp);
323 	    xfree((ptr_t) cwd);
324 	    return dp;
325 	}
326 	else {
327 	    if (!*cwd) {
328 		cwd[0] = '/';
329 		cwd[1] = '\0';
330 	    }
331 	    return cwd;
332 	}
333     }
334     return Strsave(cp);
335 }
336 
337 /*
338  * dochngd - implement chdir command.
339  */
340 void
341 /*ARGSUSED*/
dochngd(v,t)342 dochngd(v, t)
343     Char **v;
344     struct command *t;
345 {
346     Char *cp;
347     struct directory *dp;
348 
349     skipargs(&v, " [<dir>]");
350     printd = 0;
351     if (*v == NULL) {
352 	if ((cp = value(STRhome)) == NULL || *cp == 0)
353 	    stderror(ERR_NAME | ERR_NOHOMEDIR);
354 	if (chdir(short2str(cp)) < 0)
355 	    stderror(ERR_NAME | ERR_CANTCHANGE);
356 	cp = Strsave(cp);
357     }
358     else if (v[1] != NULL) {
359 	stderror(ERR_NAME | ERR_TOOMANY);
360 	/* NOTREACHED */
361 	return;
362     }
363     else if ((dp = dfind(*v)) != 0) {
364 	char   *tmp;
365 
366 	printd = 1;
367 	if (chdir(tmp = short2str(dp->di_name)) < 0)
368 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
369 	dcwd->di_prev->di_next = dcwd->di_next;
370 	dcwd->di_next->di_prev = dcwd->di_prev;
371 	dfree(dcwd);
372 	dnewcwd(dp);
373 	return;
374     }
375     else
376 	cp = dfollow(*v);
377     dp = (struct directory *) xcalloc(sizeof(struct directory), 1);
378     dp->di_name = cp;
379     dp->di_count = 0;
380     dp->di_next = dcwd->di_next;
381     dp->di_prev = dcwd->di_prev;
382     dp->di_prev->di_next = dp;
383     dp->di_next->di_prev = dp;
384     dfree(dcwd);
385     dnewcwd(dp);
386 }
387 
388 static Char *
dgoto(cp)389 dgoto(cp)
390     Char   *cp;
391 {
392     Char   *dp;
393 
394     if (*cp != '/') {
395 	Char *p, *q;
396 	int     cwdlen;
397 
398 	for (p = dcwd->di_name; *p++;)
399 	    continue;
400 	if ((cwdlen = p - dcwd->di_name - 1) == 1)	/* root */
401 	    cwdlen = 0;
402 	for (p = cp; *p++;)
403 	    continue;
404 	dp = (Char *) xmalloc((size_t)((cwdlen + (p - cp) + 1) * sizeof(Char)));
405 	for (p = dp, q = dcwd->di_name; (*p++ = *q++) != '\0';)
406 	    continue;
407 	if (cwdlen)
408 	    p[-1] = '/';
409 	else
410 	    p--;		/* don't add a / after root */
411 	for (q = cp; (*p++ = *q++) != '\0';)
412 	    continue;
413 	xfree((ptr_t) cp);
414 	cp = dp;
415 	dp += cwdlen;
416     }
417     else
418 	dp = cp;
419 
420     cp = dcanon(cp, dp);
421     return cp;
422 }
423 
424 /*
425  * dfollow - change to arg directory; fall back on cdpath if not valid
426  */
427 static Char *
dfollow(cp)428 dfollow(cp)
429     Char *cp;
430 {
431     Char *dp;
432     struct varent *c;
433     char    ebuf[MAXPATHLEN];
434     int serrno;
435 
436     cp = globone(cp, G_ERROR);
437     /*
438      * if we are ignoring symlinks, try to fix relatives now.
439      */
440     dp = dnormalize(cp);
441     if (chdir(short2str(dp)) >= 0) {
442 	xfree((ptr_t) cp);
443 	return dgoto(dp);
444     }
445     else {
446 	xfree((ptr_t) dp);
447 	if (chdir(short2str(cp)) >= 0)
448 	    return dgoto(cp);
449 	serrno = errno;
450     }
451 
452     if (cp[0] != '/' && !prefix(STRdotsl, cp) && !prefix(STRdotdotsl, cp)
453 	&& (c = adrof(STRcdpath))) {
454 	Char  **cdp;
455 	Char *p;
456 	Char    buf[MAXPATHLEN];
457 
458 	for (cdp = c->vec; *cdp; cdp++) {
459 	    for (dp = buf, p = *cdp; (*dp++ = *p++) != '\0';)
460 		continue;
461 	    dp[-1] = '/';
462 	    for (p = cp; (*dp++ = *p++) != '\0';)
463 		continue;
464 	    if (chdir(short2str(buf)) >= 0) {
465 		printd = 1;
466 		xfree((ptr_t) cp);
467 		cp = Strsave(buf);
468 		return dgoto(cp);
469 	    }
470 	}
471     }
472     dp = value(cp);
473     if ((dp[0] == '/' || dp[0] == '.') && chdir(short2str(dp)) >= 0) {
474 	xfree((ptr_t) cp);
475 	cp = Strsave(dp);
476 	printd = 1;
477 	return dgoto(cp);
478     }
479     (void) strcpy(ebuf, short2str(cp));
480     xfree((ptr_t) cp);
481     stderror(ERR_SYSTEM, ebuf, strerror(serrno));
482     return (NULL);
483 }
484 
485 
486 /*
487  * dopushd - push new directory onto directory stack.
488  *	with no arguments exchange top and second.
489  *	with numeric argument (+n) bring it to top.
490  */
491 void
492 /*ARGSUSED*/
dopushd(v,t)493 dopushd(v, t)
494     Char **v;
495     struct command *t;
496 {
497     struct directory *dp;
498 
499     skipargs(&v, " [<dir>|+<n>]");
500     printd = 1;
501     if (*v == NULL) {
502 	char   *tmp;
503 
504 	if ((dp = dcwd->di_prev) == &dhead)
505 	    dp = dhead.di_prev;
506 	if (dp == dcwd)
507 	    stderror(ERR_NAME | ERR_NODIR);
508 	if (chdir(tmp = short2str(dp->di_name)) < 0)
509 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
510 	dp->di_prev->di_next = dp->di_next;
511 	dp->di_next->di_prev = dp->di_prev;
512 	dp->di_next = dcwd->di_next;
513 	dp->di_prev = dcwd;
514 	dcwd->di_next->di_prev = dp;
515 	dcwd->di_next = dp;
516     }
517     else if (v[1] != NULL) {
518 	stderror(ERR_NAME | ERR_TOOMANY);
519 	/* NOTREACHED */
520 	return;
521     }
522     else if ((dp = dfind(*v)) != NULL) {
523 	char   *tmp;
524 
525 	if (chdir(tmp = short2str(dp->di_name)) < 0)
526 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
527     }
528     else {
529 	Char *ccp;
530 
531 	ccp = dfollow(*v);
532 	dp = (struct directory *) xcalloc(sizeof(struct directory), 1);
533 	dp->di_name = ccp;
534 	dp->di_count = 0;
535 	dp->di_prev = dcwd;
536 	dp->di_next = dcwd->di_next;
537 	dcwd->di_next = dp;
538 	dp->di_next->di_prev = dp;
539     }
540     dnewcwd(dp);
541 }
542 
543 /*
544  * dfind - find a directory if specified by numeric (+n) argument
545  */
546 static struct directory *
dfind(cp)547 dfind(cp)
548     Char *cp;
549 {
550     struct directory *dp;
551     int i;
552     Char *ep;
553 
554     if (*cp++ != '+')
555 	return (0);
556     for (ep = cp; Isdigit(*ep); ep++)
557 	continue;
558     if (*ep)
559 	return (0);
560     i = getn(cp);
561     if (i <= 0)
562 	return (0);
563     for (dp = dcwd; i != 0; i--) {
564 	if ((dp = dp->di_prev) == &dhead)
565 	    dp = dp->di_prev;
566 	if (dp == dcwd)
567 	    stderror(ERR_NAME | ERR_DEEP);
568     }
569     return (dp);
570 }
571 
572 /*
573  * dopopd - pop a directory out of the directory stack
574  *	with a numeric argument just discard it.
575  */
576 void
577 /*ARGSUSED*/
dopopd(v,t)578 dopopd(v, t)
579     Char **v;
580     struct command *t;
581 {
582     struct directory *dp, *p = NULL;
583 
584     skipargs(&v, " [+<n>]");
585     printd = 1;
586     if (*v == NULL)
587 	dp = dcwd;
588     else if (v[1] != NULL) {
589 	stderror(ERR_NAME | ERR_TOOMANY);
590 	/* NOTREACHED */
591 	return;
592     }
593     else if ((dp = dfind(*v)) == 0)
594 	stderror(ERR_NAME | ERR_BADDIR);
595     if (dp->di_prev == &dhead && dp->di_next == &dhead)
596 	stderror(ERR_NAME | ERR_EMPTY);
597     if (dp == dcwd) {
598 	char   *tmp;
599 
600 	if ((p = dp->di_prev) == &dhead)
601 	    p = dhead.di_prev;
602 	if (chdir(tmp = short2str(p->di_name)) < 0)
603 	    stderror(ERR_SYSTEM, tmp, strerror(errno));
604     }
605     dp->di_prev->di_next = dp->di_next;
606     dp->di_next->di_prev = dp->di_prev;
607     if (dp == dcwd)
608 	dnewcwd(p);
609     else {
610 	printdirs();
611     }
612     dfree(dp);
613 }
614 
615 /*
616  * dfree - free the directory (or keep it if it still has ref count)
617  */
618 void
dfree(dp)619 dfree(dp)
620     struct directory *dp;
621 {
622 
623     if (dp->di_count != 0) {
624 	dp->di_next = dp->di_prev = 0;
625     }
626     else {
627 	xfree((char *) dp->di_name);
628 	xfree((ptr_t) dp);
629     }
630 }
631 
632 /*
633  * dcanon - canonicalize the pathname, removing excess ./ and ../ etc.
634  *	we are of course assuming that the file system is standardly
635  *	constructed (always have ..'s, directories have links)
636  */
637 Char   *
dcanon(cp,p)638 dcanon(cp, p)
639     Char *cp, *p;
640 {
641     Char *sp;
642     Char *p1, *p2;	/* general purpose */
643     bool    slash;
644 
645     Char    link[MAXPATHLEN];
646     char    tlink[MAXPATHLEN];
647     int     cc;
648     Char   *newcp;
649 
650     /*
651      * christos: if the path given does not start with a slash prepend cwd. If
652      * cwd does not start with a path or the result would be too long abort().
653      */
654     if (*cp != '/') {
655 	Char    tmpdir[MAXPATHLEN];
656 
657 	p1 = value(STRcwd);
658 	if (p1 == NULL || *p1 != '/')
659 	    abort();
660 	if (Strlen(p1) + Strlen(cp) + 1 >= MAXPATHLEN)
661 	    abort();
662 	(void) Strcpy(tmpdir, p1);
663 	(void) Strcat(tmpdir, STRslash);
664 	(void) Strcat(tmpdir, cp);
665 	xfree((ptr_t) cp);
666 	cp = p = Strsave(tmpdir);
667     }
668 
669     while (*p) {		/* for each component */
670 	sp = p;			/* save slash address */
671 	while (*++p == '/')	/* flush extra slashes */
672 	    continue;
673 	if (p != ++sp)
674 	    for (p1 = sp, p2 = p; (*p1++ = *p2++) != '\0';)
675 		continue;
676 	p = sp;			/* save start of component */
677 	slash = 0;
678 	while (*++p)		/* find next slash or end of path */
679 	    if (*p == '/') {
680 		slash = 1;
681 		*p = 0;
682 		break;
683 	    }
684 
685 	if (*sp == '\0')	/* if component is null */
686 	    if (--sp == cp)	/* if path is one char (i.e. /) */
687 		break;
688 	    else
689 		*sp = '\0';
690 	else if (sp[0] == '.' && sp[1] == 0) {
691 	    if (slash) {
692 		for (p1 = sp, p2 = p + 1; (*p1++ = *p2++) != '\0';)
693 		    continue;
694 		p = --sp;
695 	    }
696 	    else if (--sp != cp)
697 		*sp = '\0';
698 	}
699 	else if (sp[0] == '.' && sp[1] == '.' && sp[2] == 0) {
700 	    /*
701 	     * We have something like "yyy/xxx/..", where "yyy" can be null or
702 	     * a path starting at /, and "xxx" is a single component. Before
703 	     * compressing "xxx/..", we want to expand "yyy/xxx", if it is a
704 	     * symbolic link.
705 	     */
706 	    *--sp = 0;		/* form the pathname for readlink */
707 	    if (sp != cp && !adrof(STRignore_symlinks) &&
708 		(cc = readlink(short2str(cp), tlink, sizeof(tlink) - 1)) >= 0) {
709 		(void) Strcpy(link, str2short(tlink));
710 		link[cc] = '\0';
711 
712 		if (slash)
713 		    *p = '/';
714 		/*
715 		 * Point p to the '/' in "/..", and restore the '/'.
716 		 */
717 		*(p = sp) = '/';
718 		/*
719 		 * find length of p
720 		 */
721 		for (p1 = p; *p1++;)
722 		    continue;
723 		if (*link != '/') {
724 		    /*
725 		     * Relative path, expand it between the "yyy/" and the
726 		     * "/..". First, back sp up to the character past "yyy/".
727 		     */
728 		    while (*--sp != '/')
729 			continue;
730 		    sp++;
731 		    *sp = 0;
732 		    /*
733 		     * New length is "yyy/" + link + "/.." and rest
734 		     */
735 		    p1 = newcp = (Char *) xmalloc((size_t)
736 						(((sp - cp) + cc + (p1 - p)) *
737 						 sizeof(Char)));
738 		    /*
739 		     * Copy new path into newcp
740 		     */
741 		    for (p2 = cp; (*p1++ = *p2++) != '\0';)
742 			continue;
743 		    for (p1--, p2 = link; (*p1++ = *p2++) != '\0';)
744 			continue;
745 		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
746 			continue;
747 		    /*
748 		     * Restart canonicalization at expanded "/xxx".
749 		     */
750 		    p = sp - cp - 1 + newcp;
751 		}
752 		else {
753 		    /*
754 		     * New length is link + "/.." and rest
755 		     */
756 		    p1 = newcp = (Char *) xmalloc((size_t)
757 					    ((cc + (p1 - p)) * sizeof(Char)));
758 		    /*
759 		     * Copy new path into newcp
760 		     */
761 		    for (p2 = link; (*p1++ = *p2++) != '\0';)
762 			continue;
763 		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
764 			continue;
765 		    /*
766 		     * Restart canonicalization at beginning
767 		     */
768 		    p = newcp;
769 		}
770 		xfree((ptr_t) cp);
771 		cp = newcp;
772 		continue;	/* canonicalize the link */
773 	    }
774 	    *sp = '/';
775 	    if (sp != cp)
776 		while (*--sp != '/')
777 		    continue;
778 	    if (slash) {
779 		for (p1 = sp + 1, p2 = p + 1; (*p1++ = *p2++) != '\0';)
780 		    continue;
781 		p = sp;
782 	    }
783 	    else if (cp == sp)
784 		*++sp = '\0';
785 	    else
786 		*sp = '\0';
787 	}
788 	else {			/* normal dir name (not . or .. or nothing) */
789 
790 	    if (sp != cp && adrof(STRchase_symlinks) &&
791 		!adrof(STRignore_symlinks) &&
792 		(cc = readlink(short2str(cp), tlink, sizeof(tlink) - 1)) >= 0) {
793 		(void) Strcpy(link, str2short(tlink));
794 		link[cc] = '\0';
795 
796 		/*
797 		 * restore the '/'.
798 		 */
799 		if (slash)
800 		    *p = '/';
801 
802 		/*
803 		 * point sp to p (rather than backing up).
804 		 */
805 		sp = p;
806 
807 		/*
808 		 * find length of p
809 		 */
810 		for (p1 = p; *p1++;)
811 		    continue;
812 		if (*link != '/') {
813 		    /*
814 		     * Relative path, expand it between the "yyy/" and the
815 		     * remainder. First, back sp up to the character past
816 		     * "yyy/".
817 		     */
818 		    while (*--sp != '/')
819 			continue;
820 		    sp++;
821 		    *sp = 0;
822 		    /*
823 		     * New length is "yyy/" + link + "/.." and rest
824 		     */
825 		    p1 = newcp = (Char *) xmalloc((size_t)
826 						  (((sp - cp) + cc + (p1 - p))
827 						   * sizeof(Char)));
828 		    /*
829 		     * Copy new path into newcp
830 		     */
831 		    for (p2 = cp; (*p1++ = *p2++) != '\0';)
832 			continue;
833 		    for (p1--, p2 = link; (*p1++ = *p2++) != '\0';)
834 			continue;
835 		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
836 			continue;
837 		    /*
838 		     * Restart canonicalization at expanded "/xxx".
839 		     */
840 		    p = sp - cp - 1 + newcp;
841 		}
842 		else {
843 		    /*
844 		     * New length is link + the rest
845 		     */
846 		    p1 = newcp = (Char *) xmalloc((size_t)
847 					    ((cc + (p1 - p)) * sizeof(Char)));
848 		    /*
849 		     * Copy new path into newcp
850 		     */
851 		    for (p2 = link; (*p1++ = *p2++) != '\0';)
852 			continue;
853 		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
854 			continue;
855 		    /*
856 		     * Restart canonicalization at beginning
857 		     */
858 		    p = newcp;
859 		}
860 		xfree((ptr_t) cp);
861 		cp = newcp;
862 		continue;	/* canonicalize the link */
863 	    }
864 	    if (slash)
865 		*p = '/';
866 	}
867     }
868 
869     /*
870      * fix home...
871      */
872     p1 = value(STRhome);
873     cc = Strlen(p1);
874     /*
875      * See if we're not in a subdir of STRhome
876      */
877     if (p1 && *p1 == '/' &&
878 	(Strncmp(p1, cp, cc) != 0 || (cp[cc] != '/' && cp[cc] != '\0'))) {
879 	static ino_t home_ino = -1;
880 	static dev_t home_dev = -1;
881 	static Char *home_ptr = NULL;
882 	struct stat statbuf;
883 
884 	/*
885 	 * Get dev and ino of STRhome
886 	 */
887 	if (home_ptr != p1 &&
888 	    stat(short2str(p1), &statbuf) != -1) {
889 	    home_dev = statbuf.st_dev;
890 	    home_ino = statbuf.st_ino;
891 	    home_ptr = p1;
892 	}
893 	/*
894 	 * Start comparing dev & ino backwards
895 	 */
896 	p2 = Strcpy(link, cp);
897 	for (sp = NULL; *p2 && stat(short2str(p2), &statbuf) != -1;) {
898 	    if (statbuf.st_dev == home_dev &&
899 		statbuf.st_ino == home_ino) {
900 		sp = (Char *) - 1;
901 		break;
902 	    }
903 	    if ((sp = Strrchr(p2, '/')) != NULL)
904 		*sp = '\0';
905 	}
906 	/*
907 	 * See if we found it
908 	 */
909 	if (*p2 && sp == (Char *) -1) {
910 	    /*
911 	     * Use STRhome to make '~' work
912 	     */
913 	    newcp = Strspl(p1, cp + Strlen(p2));
914 	    xfree((ptr_t) cp);
915 	    cp = newcp;
916 	}
917     }
918     return cp;
919 }
920 
921 
922 /*
923  * dnewcwd - make a new directory in the loop the current one
924  */
925 static void
dnewcwd(dp)926 dnewcwd(dp)
927     struct directory *dp;
928 {
929     dcwd = dp;
930     dset(dcwd->di_name);
931     if (printd && !(adrof(STRpushdsilent)))
932 	printdirs();
933 }
934