/usr/src/bin/csh/dir.c

Bug Summary

File:	src/bin/csh/dir.c
Warning:	line 562, column 9 Access to field 'di_prev' results in a dereference of a null pointer (loaded from variable 'dp')

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.4 -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name dir.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/bin/csh/obj -resource-dir /usr/local/llvm16/lib/clang/16 -I /usr/src/bin/csh -I . -internal-isystem /usr/local/llvm16/lib/clang/16/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/bin/csh/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fcf-protection=branch -fno-jump-tables -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/scan/2024-01-11-140451-98009-1 -x c /usr/src/bin/csh/dir.c

1/*	$OpenBSD: dir.c,v 1.26 2023/03/08 04:43:04 guenther Exp $	*/
2/*	$NetBSD: dir.c,v 1.9 1995/03/21 09:02:42 cgd Exp $	*/

4/*-
* Copyright (c) 1980, 1991, 1993
*	The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

33#include <sys/stat.h>
34#include <errno(*__errno()).h>
35#include <stdlib.h>
36#include <string.h>
37#include <unistd.h>
38#include <limits.h>
39#include <stdarg.h>

41#include "csh.h"
42#include "dir.h"
43#include "extern.h"

45/* Directory management. */

47static struct directory
*dfind(Char *);
49static Char	*dfollow(Char *);
50static void	 printdirs(void);
51static Char	*dgoto(Char *);
52static void	 dnewcwd(struct directory *);
53static void	 dset(Char *);

55struct directory dhead;		/* "head" of loop */
56struct directory *dcwd;		/* the one we are in now */
57int     printd;			/* force name to be printed */

59static int dirflag = 0;

61/*
* dinit - initialize current working directory
*/
64void
65dinit(Char *hp)
66{
  char *tcp;
  Char *cp = NULL((void *)0);
  struct directory *dp;
  char    path[PATH_MAX1024];
  static const char emsg[] = "csh: Trying to start from \"%s\"\n";

  /* Don't believe the login shell home, because it may be a symlink */
  tcp = getcwd(path, PATH_MAX1024);
  if (tcp == NULL((void *)0) || *tcp == '\0') {
(void) fprintf(csherr, "csh: %s\n", strerror(errno(*__errno())));
if (hp && *hp) {
   tcp = short2str(hp);
   if (chdir(tcp) == 0)
cp = hp;
   (void) fprintf(csherr, emsg, vis_str(hp));
}
  }
  else {
struct stat swd, shp;

if (stat(tcp, &swd) == -1) {
   (void) fprintf(csherr, "csh: %s: %s\n", tcp, strerror(errno(*__errno())));
} else {
   /*
    * See if $HOME is the working directory we got and use that
    */
   if (hp && *hp && stat(short2str(hp), &shp) != -1 &&
swd.st_dev == shp.st_dev && swd.st_ino == shp.st_ino)
cp = hp;
   else {
char   *cwd;

/*
 * use PWD if we have it (for subshells)
 */
if ((cwd = getenv("PWD")) != NULL((void *)0)) {
    if (stat(cwd, &shp) != -1 && swd.st_dev == shp.st_dev &&
	swd.st_ino == shp.st_ino)
	tcp = cwd;
}
cp = dcanon(SAVE(tcp)(Strsave(str2short(tcp))), STRNULL);
   }
}
  }

  if (cp == NULL((void *)0)) {
(void) fprintf(csherr, emsg, "/");
if (chdir("/") == -1)
   /* I am not even try to print an error message! */
   xexit(1);
cp = SAVE("/")(Strsave(str2short("/")));
  }

  dp = xcalloc(1, sizeof(struct directory));
  dp->di_name = Strsave(cp);
  dp->di_count = 0;
  dhead.di_next = dhead.di_prev = dp;
  dp->di_next = dp->di_prev = &dhead;
  printd = 0;
  dnewcwd(dp);
127}

129static void
130dset(Char *dp)
131{
  /*
   * Don't call set() directly cause if the directory contains ` or
   * other junk characters glob will fail.
   */
  Char **vec = xreallocarray(NULL((void *)0), 2, sizeof(*vec));

  vec[0] = Strsave(dp);
  vec[1] = 0;
  setq(STRcwd, vec, &shvhed);
  Setenv(STRPWD, dp);
142}

144#define DIR_LONG1 1
145#define DIR_VERT2 2
146#define DIR_LINE4 4

148static void
149skipargs(Char ***v, char *str)
150{
  Char  **n = *v, *s;

  dirflag = 0;
  for (n++; *n != NULL((void *)0) && (*n)[0] == '-'; n++)
for (s = &((*n)[1]); *s; s++)
   switch (*s) {
   case 'l':
dirflag |= DIR_LONG1;
break;
   case 'v':
dirflag |= DIR_VERT2;
break;
   case 'n':
dirflag |= DIR_LINE4;
break;
   default:
stderror(ERR_DIRUS69, vis_str(**v), str);
break;
   }
  *v = n;
171}

173/*
* dodirs - list all directories in directory loop
*/
176void
177dodirs(Char **v, struct command *t)
178{
  skipargs(&v, "");

  if (*v != NULL((void *)0))
stderror(ERR_DIRUS69, "dirs", "");
  printdirs();
184}

186static void
187printdirs(void)
188{
  struct directory *dp;
  Char   *s, *hp = value(STRhome)value1(STRhome, &shvhed);
  int     idx, len, cur;

  if (*hp == '\0')
hp = NULL((void *)0);
  dp = dcwd;
  idx = 0;
  cur = 0;
  do {
if (dp == &dhead)
   continue;
if (dirflag & DIR_VERT2) {
   (void) fprintf(cshout, "%d\t", idx++);
   cur = 0;
}
if (!(dirflag & DIR_LONG1) && hp != NULL((void *)0) && !eq(hp, STRslash)(Strcmp(hp, STRslash) == 0) &&
   (len = Strlen(hp), Strncmp(hp, dp->di_name, len) == 0) &&
   (dp->di_name[len] == '\0' || dp->di_name[len] == '/'))
   len = Strlen(s = (dp->di_name + len)) + 2;
else
   len = Strlen(s = dp->di_name) + 1;

cur += len;
if ((dirflag & DIR_LINE4) && cur >= 80 - 1 && len < 80) {
   (void) fprintf(cshout, "\n");
   cur = len;
}
(void) fprintf(cshout, s != dp->di_name ? "~%s%c" : "%s%c",
vis_str(s), (dirflag & DIR_VERT2) ? '\n' : ' ');
  } while ((dp = dp->di_prev) != dcwd);
  if (!(dirflag & DIR_VERT2))
(void) fprintf(cshout, "\n");
222}

224void
225dtildepr(Char *home, Char *dir)
226{

  if (!eq(home, STRslash)(Strcmp(home, STRslash) == 0) && prefix(home, dir))
(void) fprintf(cshout, "~%s", vis_str(dir + Strlen(home)));
  else
(void) fprintf(cshout, "%s", vis_str(dir));
232}

234void
235dtilde(void)
236{
  struct directory *d = dcwd;

  do {
if (d == &dhead)
   continue;
d->di_name = dcanon(d->di_name, STRNULL);
  } while ((d = d->di_prev) != dcwd);

  dset(dcwd->di_name);
246}


249/* dnormalize():
*	If the name starts with . or .. then we might need to normalize
*	it depending on the symbolic link flags
*/
253Char   *
254dnormalize(Char *cp)
255{

257#define UC(unsigned char) (unsigned char)
258#define ISDOT(c)((unsigned char)(c)[0] == '.' && (((unsigned char)(c)
[1] == '\0') || ((unsigned char)(c)[1] == '/'))) (UC(unsigned char)(c)[0] == '.' && ((UC(unsigned char)(c)[1] == '\0') || (UC(unsigned char)(c)[1] == '/')))
259#define ISDOTDOT(c)((unsigned char)(c)[0] == '.' && ((unsigned char)(&
((c)[1]))[0] == '.' && (((unsigned char)(&((c)[1]
))[1] == '\0') || ((unsigned char)(&((c)[1]))[1] == '/'))
)) (UC(unsigned char)(c)[0] == '.' && ISDOT(&((c)[1]))((unsigned char)(&((c)[1]))[0] == '.' && (((unsigned
 char)(&((c)[1]))[1] == '\0') || ((unsigned char)(&((
c)[1]))[1] == '/'))))

  if ((unsigned char) cp[0] == '/')
return (Strsave(cp));

  if (adrof(STRignore_symlinks)adrof1(STRignore_symlinks, &shvhed)) {
int     dotdot = 0;
Char   *dp, *cwd;
size_t	len;

len = (size_t) (Strlen(dcwd->di_name) + 3);
cwd = xreallocarray(NULL((void *)0), len, sizeof(Char));
(void) Strlcpy(cwd, dcwd->di_name, len);

/*
* Ignore . and count ..'s
*/
while (*cp) {
   if (ISDOT(cp)((unsigned char)(cp)[0] == '.' && (((unsigned char)(cp
)[1] == '\0') || ((unsigned char)(cp)[1] == '/')))) {
if (*++cp)
    cp++;
   }
   else if (ISDOTDOT(cp)((unsigned char)(cp)[0] == '.' && ((unsigned char)(&
((cp)[1]))[0] == '.' && (((unsigned char)(&((cp)[
1]))[1] == '\0') || ((unsigned char)(&((cp)[1]))[1] == '/'
))))) {
dotdot++;
cp += 2;
if (*cp)
    cp++;
   }
   else
break;
}
while (dotdot > 0)
   if ((dp = Strrchr(cwd, '/'))) {
*dp = '\0';
dotdot--;
   }
   else
break;

if (*cp) {
   cwd[dotdot = Strlen(cwd)] = '/';
   cwd[dotdot + 1] = '\0';
   dp = Strspl(cwd, cp);
   free(cwd);
   return dp;
}
else {
   if (!*cwd) {
cwd[0] = '/';
cwd[1] = '\0';
   }
   return cwd;
}
  }
  return Strsave(cp);
314}

316/*
* dochngd - implement chdir command.
*/
319void
320dochngd(Char **v, struct command *t)
321{
  Char *cp;
  struct directory *dp;

  skipargs(&v, " [<dir>]");
  printd = 0;
  if (*v == NULL((void *)0)) {
if ((cp = value(STRhome)value1(STRhome, &shvhed)) == NULL((void *)0) || *cp == 0)
   stderror(ERR_NAME0x10000000 | ERR_NOHOMEDIR35);
if (chdir(short2str(cp)) == -1)
   stderror(ERR_NAME0x10000000 | ERR_CANTCHANGE36);
cp = Strsave(cp);
  }
  else if (v[1] != NULL((void *)0)) {
stderror(ERR_NAME0x10000000 | ERR_TOOMANY16);
/* NOTREACHED */
return;
  }
  else if ((dp = dfind(*v)) != 0) {
char   *tmp;

printd = 1;
if (chdir(tmp = short2str(dp->di_name)) == -1)
   stderror(ERR_SYSTEM55, tmp, strerror(errno(*__errno())));
dcwd->di_prev->di_next = dcwd->di_next;
dcwd->di_next->di_prev = dcwd->di_prev;
dfree(dcwd);
dnewcwd(dp);
return;
  }
  else
cp = dfollow(*v);
  dp = xcalloc(1, sizeof(struct directory));
  dp->di_name = cp;
  dp->di_count = 0;
  dp->di_next = dcwd->di_next;
  dp->di_prev = dcwd->di_prev;
  dp->di_prev->di_next = dp;
  dp->di_next->di_prev = dp;
  dfree(dcwd);
  dnewcwd(dp);
362}

364static Char *
365dgoto(Char *cp)
366{
  Char   *dp;

  if (*cp != '/') {
Char *p, *q;
int     cwdlen;

for (p = dcwd->di_name; *p++;)
   continue;
if ((cwdlen = p - dcwd->di_name - 1) == 1)	/* root */
   cwdlen = 0;
for (p = cp; *p++;)
   continue;
dp = xreallocarray(NULL((void *)0), (cwdlen + (p - cp) + 1), sizeof(Char));
for (p = dp, q = dcwd->di_name; (*p++ = *q++) != '\0';)
   continue;
if (cwdlen)
   p[-1] = '/';
else
   p--;		/* don't add a / after root */
for (q = cp; (*p++ = *q++) != '\0';)
   continue;
free(cp);
cp = dp;
dp += cwdlen;
  }
  else
dp = cp;

  cp = dcanon(cp, dp);
  return cp;
397}

399/*
* dfollow - change to arg directory; fall back on cdpath if not valid
*/
402static Char *
403dfollow(Char *cp)
404{
  Char *dp;
  struct varent *c;
  char    ebuf[PATH_MAX1024];
  int serrno;

  cp = globone(cp, G_ERROR0);
  /*
   * if we are ignoring symlinks, try to fix relatives now.
   */
  dp = dnormalize(cp);
  if (chdir(short2str(dp)) >= 0) {
free(cp);
return dgoto(dp);
  }
  else {
free(dp);
if (chdir(short2str(cp)) >= 0)
   return dgoto(cp);
serrno = errno(*__errno());
  }

  if (cp[0] != '/' && !prefix(STRdotsl, cp) && !prefix(STRdotdotsl, cp)
&& (c = adrof(STRcdpath)adrof1(STRcdpath, &shvhed))) {
Char  **cdp;
Char *p;
Char    buf[PATH_MAX1024];

for (cdp = c->vec; *cdp; cdp++) {
   for (dp = buf, p = *cdp; (*dp++ = *p++) != '\0';)
continue;
   dp[-1] = '/';
   for (p = cp; (*dp++ = *p++) != '\0';)
continue;
   if (chdir(short2str(buf)) >= 0) {
printd = 1;
free(cp);
cp = Strsave(buf);
return dgoto(cp);
   }
}
  }
  dp = value(cp)value1(cp, &shvhed);
  if ((dp[0] == '/' || dp[0] == '.') && chdir(short2str(dp)) >= 0) {
free(cp);
cp = Strsave(dp);
printd = 1;
return dgoto(cp);
  }
  (void) strlcpy(ebuf, short2str(cp), sizeof ebuf);
  free(cp);
  stderror(ERR_SYSTEM55, ebuf, strerror(serrno));
  return (NULL((void *)0));
457}


460/*
* dopushd - push new directory onto directory stack.
*	with no arguments exchange top and second.
*	with numeric argument (+n) bring it to top.
*/
465void
466dopushd(Char **v, struct command *t)
467{
  struct directory *dp;

  skipargs(&v, " [<dir>|+<n>]");
  printd = 1;
  if (*v == NULL((void *)0)) {
char   *tmp;

if ((dp = dcwd->di_prev) == &dhead)
   dp = dhead.di_prev;
if (dp == dcwd)
   stderror(ERR_NAME0x10000000 | ERR_NODIR66);
if (chdir(tmp = short2str(dp->di_name)) == -1)
   stderror(ERR_SYSTEM55, tmp, strerror(errno(*__errno())));
dp->di_prev->di_next = dp->di_next;
dp->di_next->di_prev = dp->di_prev;
dp->di_next = dcwd->di_next;
dp->di_prev = dcwd;
dcwd->di_next->di_prev = dp;
dcwd->di_next = dp;
  }
  else if (v[1] != NULL((void *)0)) {
stderror(ERR_NAME0x10000000 | ERR_TOOMANY16);
/* NOTREACHED */
return;
  }
  else if ((dp = dfind(*v)) != NULL((void *)0)) {
char   *tmp;

if (chdir(tmp = short2str(dp->di_name)) == -1)
   stderror(ERR_SYSTEM55, tmp, strerror(errno(*__errno())));
  }
  else {
Char *ccp;

ccp = dfollow(*v);
dp = xcalloc(1, sizeof(struct directory));
dp->di_name = ccp;
dp->di_count = 0;
dp->di_prev = dcwd;
dp->di_next = dcwd->di_next;
dcwd->di_next = dp;
dp->di_next->di_prev = dp;
  }
  dnewcwd(dp);
512}

514/*
* dfind - find a directory if specified by numeric (+n) argument
*/
517static struct directory *
518dfind(Char *cp)
519{
  struct directory *dp;
  int i;
  Char *ep;

  if (*cp++ != '+')
return (0);
  for (ep = cp; Isdigit(*ep)(((*ep) & 0100000U) ? 0 : isdigit((unsigned char) (*ep))); ep++)
continue;
  if (*ep)
return (0);
  i = getn(cp);
  if (i <= 0)
return (0);
  for (dp = dcwd; i != 0; i--) {
if ((dp = dp->di_prev) == &dhead)
   dp = dp->di_prev;
if (dp == dcwd)
   stderror(ERR_NAME0x10000000 | ERR_DEEP27);
  }
  return (dp);
540}

542/*
* dopopd - pop a directory out of the directory stack
*	with a numeric argument just discard it.
*/
546void
547dopopd(Char **v, struct command *t)
548{
  struct directory *dp, *p = NULL((void *)0);

  skipargs(&v, " [+<n>]");
  printd = 1;
  if (*v == NULL((void *)0))
1
Assuming the condition is false→
2
←
Taking false branch→
dp = dcwd;
  else if (v[1] != NULL((void *)0)) {
3
←
Assuming the condition is false→
4
←
Taking false branch→
stderror(ERR_NAME0x10000000 | ERR_TOOMANY16);
/* NOTREACHED */
return;
  }
  else if ((dp = dfind(*v)) == 0)
5
←
Value assigned to 'dp'→
6
←
Assuming pointer value is null→
7
←
Taking true branch→
stderror(ERR_NAME0x10000000 | ERR_BADDIR68);
  if (dp->di_prev == &dhead && dp->di_next == &dhead)
8
←
Access to field 'di_prev' results in a dereference of a null pointer (loaded from variable 'dp')
stderror(ERR_NAME0x10000000 | ERR_EMPTY67);
  if (dp == dcwd) {
char   *tmp;

if ((p = dp->di_prev) == &dhead)
   p = dhead.di_prev;
if (chdir(tmp = short2str(p->di_name)) == -1)
   stderror(ERR_SYSTEM55, tmp, strerror(errno(*__errno())));
  }
  dp->di_prev->di_next = dp->di_next;
  dp->di_next->di_prev = dp->di_prev;
  if (dp == dcwd)
dnewcwd(p);
  else {
printdirs();
  }
  dfree(dp);
580}

582/*
* dfree - free the directory (or keep it if it still has ref count)
*/
585void
586dfree(struct directory *dp)
587{

  if (dp->di_count != 0) {
dp->di_next = dp->di_prev = 0;
  }
  else {
free((char *) dp->di_name);
free(dp);
  }
596}

598/*
* dcanon - canonicalize the pathname, removing excess ./ and ../ etc.
*	we are of course assuming that the file system is standardly
*	constructed (always have ..'s, directories have links)
*/
603Char   *
604dcanon(Char *cp, Char *p)
605{
  Char *sp;
  Char *p1, *p2;	/* general purpose */
  bool    slash;

  Char    link[PATH_MAX1024];
  char    tlink[PATH_MAX1024];
  int     cc;
  Char   *newcp;

  /*
   * christos: if the path given does not start with a slash prepend cwd. If
   * cwd does not start with a path or the result would be too long abort().
   */
  if (*cp != '/') {
Char    tmpdir[PATH_MAX1024];

p1 = value(STRcwd)value1(STRcwd, &shvhed);
if (p1 == NULL((void *)0) || *p1 != '/')
   abort();
if (Strlen(p1) + Strlen(cp) + 1 >= PATH_MAX1024)
   abort();
(void) Strlcpy(tmpdir, p1, sizeof tmpdir/sizeof(Char));
(void) Strlcat(tmpdir, STRslash, sizeof tmpdir/sizeof(Char));
(void) Strlcat(tmpdir, cp, sizeof tmpdir/sizeof(Char));
free(cp);
cp = p = Strsave(tmpdir);
  }

  while (*p) {		/* for each component */
sp = p;			/* save slash address */
while (*++p == '/')	/* flush extra slashes */
   continue;
if (p != ++sp)
   for (p1 = sp, p2 = p; (*p1++ = *p2++) != '\0';)
continue;
p = sp;			/* save start of component */
slash = 0;
while (*p)		/* find next slash or end of path */
   if (*++p == '/') {
slash = 1;
*p = 0;
break;
   }

if (*sp == '\0')	/* if component is null */
   if (--sp == cp)	/* if path is one char (i.e. /) */
break;
   else
*sp = '\0';
else if (sp[0] == '.' && sp[1] == 0) {
   if (slash) {
for (p1 = sp, p2 = p + 1; (*p1++ = *p2++) != '\0';)
    continue;
p = --sp;
   }
   else if (--sp != cp)
*sp = '\0';
}
else if (sp[0] == '.' && sp[1] == '.' && sp[2] == 0) {
   /*
    * We have something like "yyy/xxx/..", where "yyy" can be null or
    * a path starting at /, and "xxx" is a single component. Before
    * compressing "xxx/..", we want to expand "yyy/xxx", if it is a
    * symbolic link.
    */
   *--sp = 0;		/* form the pathname for readlink */
   if (sp != cp && !adrof(STRignore_symlinks)adrof1(STRignore_symlinks, &shvhed) &&
(cc = readlink(short2str(cp), tlink,
	       sizeof tlink-1)) >= 0) {
tlink[cc] = '\0';
(void) Strlcpy(link, str2short(tlink), sizeof link/sizeof(Char));

if (slash)
    *p = '/';
/*
 * Point p to the '/' in "/..", and restore the '/'.
 */
*(p = sp) = '/';
/*
 * find length of p
 */
for (p1 = p; *p1++;)
    continue;
if (*link != '/') {
    /*
     * Relative path, expand it between the "yyy/" and the
     * "/..". First, back sp up to the character past "yyy/".
     */
    while (*--sp != '/')
	continue;
    sp++;
    *sp = 0;
    /*
     * New length is "yyy/" + link + "/.." and rest
     */
    p1 = newcp = xreallocarray(NULL((void *)0),
	(sp - cp) + cc + (p1 - p), sizeof(Char));
    /*
     * Copy new path into newcp
     */
    for (p2 = cp; (*p1++ = *p2++) != '\0';)
	continue;
    for (p1--, p2 = link; (*p1++ = *p2++) != '\0';)
	continue;
    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
	continue;
    /*
     * Restart canonicalization at expanded "/xxx".
     */
    p = sp - cp - 1 + newcp;
}
else {
    /*
     * New length is link + "/.." and rest
     */
    p1 = newcp = xreallocarray(NULL((void *)0), cc + (p1 - p),
        sizeof(Char));
    /*
     * Copy new path into newcp
     */
    for (p2 = link; (*p1++ = *p2++) != '\0';)
	continue;
    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
	continue;
    /*
     * Restart canonicalization at beginning
     */
    p = newcp;
}
free(cp);
cp = newcp;
continue;	/* canonicalize the link */
   }
   *sp = '/';
   if (sp != cp)
while (*--sp != '/')
    continue;
   if (slash) {
for (p1 = sp + 1, p2 = p + 1; (*p1++ = *p2++) != '\0';)
    continue;
p = sp;
   }
   else if (cp == sp)
*++sp = '\0';
   else
*sp = '\0';
}
else {			/* normal dir name (not . or .. or nothing) */

   if (sp != cp && adrof(STRchase_symlinks)adrof1(STRchase_symlinks, &shvhed) &&
!adrof(STRignore_symlinks)adrof1(STRignore_symlinks, &shvhed) &&
(cc = readlink(short2str(cp), tlink,
	       sizeof tlink-1)) >= 0) {
tlink[cc] = '\0';
(void) Strlcpy(link, str2short(tlink), sizeof link/sizeof(Char));

/*
 * restore the '/'.
 */
if (slash)
    *p = '/';

/*
 * point sp to p (rather than backing up).
 */
sp = p;

/*
 * find length of p
 */
for (p1 = p; *p1++;)
    continue;
if (*link != '/') {
    /*
     * Relative path, expand it between the "yyy/" and the
     * remainder. First, back sp up to the character past
     * "yyy/".
     */
    while (*--sp != '/')
	continue;
    sp++;
    *sp = 0;
    /*
     * New length is "yyy/" + link + "/.." and rest
     */
    p1 = newcp = xreallocarray(NULL((void *)0),
	  (sp - cp) + cc + (p1 - p), sizeof(Char));
    /*
     * Copy new path into newcp
     */
    for (p2 = cp; (*p1++ = *p2++) != '\0';)
	continue;
    for (p1--, p2 = link; (*p1++ = *p2++) != '\0';)
	continue;
    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
	continue;
    /*
     * Restart canonicalization at expanded "/xxx".
     */
    p = sp - cp - 1 + newcp;
}
else {
    /*
     * New length is link + the rest
     */
    p1 = newcp = xreallocarray(NULL((void *)0), cc + (p1 - p), sizeof(Char));
    /*
     * Copy new path into newcp
     */
    for (p2 = link; (*p1++ = *p2++) != '\0';)
	continue;
    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
	continue;
    /*
     * Restart canonicalization at beginning
     */
    p = newcp;
}
free(cp);
cp = newcp;
continue;	/* canonicalize the link */
   }
   if (slash)
*p = '/';
}
  }

  /*
   * fix home...
   */
  p1 = value(STRhome)value1(STRhome, &shvhed);
  cc = Strlen(p1);
  /*
   * See if we're not in a subdir of STRhome
   */
  if (p1 && *p1 == '/' &&
(Strncmp(p1, cp, cc) != 0 || (cp[cc] != '/' && cp[cc] != '\0'))) {
static ino_t home_ino = -1;
static dev_t home_dev = -1;
static Char *home_ptr = NULL((void *)0);
struct stat statbuf;

/*
* Get dev and ino of STRhome
*/
if (home_ptr != p1 &&
   stat(short2str(p1), &statbuf) != -1) {
   home_dev = statbuf.st_dev;
   home_ino = statbuf.st_ino;
   home_ptr = p1;
}
/*
* Start comparing dev & ino backwards
*/
Strlcpy(link, cp, sizeof link/sizeof(Char));
p2 = link;
for (sp = NULL((void *)0); *p2 && stat(short2str(p2), &statbuf) != -1;) {
   if (statbuf.st_dev == home_dev &&
statbuf.st_ino == home_ino) {
sp = (Char *) - 1;
break;
   }
   if ((sp = Strrchr(p2, '/')) != NULL((void *)0))
*sp = '\0';
}
/*
* See if we found it
*/
if (*p2 && sp == (Char *) -1) {
   /*
    * Use STRhome to make '~' work
    */
   newcp = Strspl(p1, cp + Strlen(p2));
   free(cp);
   cp = newcp;
}
  }
  return cp;
884}


887/*
* dnewcwd - make a new directory in the loop the current one
*/
890static void
891dnewcwd(struct directory *dp)
892{
  dcwd = dp;
  dset(dcwd->di_name);
  if (printd && !(adrof(STRpushdsilent)adrof1(STRpushdsilent, &shvhed)))
printdirs();
897}