Upgrade Cwd.xs to the Cwd.xs in PathTools 3.26_01:
authorNicholas Clark <nick@ccl4.org>
Mon, 27 Oct 2008 20:29:54 +0000 (20:29 +0000)
committerNicholas Clark <nick@ccl4.org>
Mon, 27 Oct 2008 20:29:54 +0000 (20:29 +0000)
- abs_path() on Unix(ish) platforms has been upgraded to a much later
  version of the underlying C code from BSD. [Michael Schwern]

- If strlcpy() and strlcat() aren't available on the user's system,
  we now use ppport.h to provide them, so our C code works. [Steve
  Peters]

This unwinds change 32710 (consting from Robin Barker of the old code)

p4raw-id: //depot/perl@34606

ext/Cwd/Cwd.xs

index 4864ba1..949b94c 100644 (file)
  */
 static
 char *
-bsd_realpath(const char *path, char *resolved)
+bsd_realpath(const char *path, char resolved[MAXPATHLEN])
 {
 #ifdef VMS
        dTHX;
        return Perl_rmsexpand(aTHX_ (char*)path, resolved, NULL, 0);
 #else
-       int rootd, serrno;
-       const char *p;
-       char *q, wbuf[MAXPATHLEN];
-       int symlinks = 0;
-
-       /* Save the starting point. */
-#ifdef HAS_FCHDIR
-       int fd;
-
-       if ((fd = open(".", O_RDONLY)) < 0) {
-               (void)strcpy(resolved, ".");
+       char *p, *q, *s;
+       size_t left_len, resolved_len;
+       unsigned symlinks;
+       int serrno;
+       char left[MAXPATHLEN], next_token[MAXPATHLEN], symlink[MAXPATHLEN];
+
+       serrno = errno;
+       symlinks = 0;
+       if (path[0] == '/') {
+               resolved[0] = '/';
+               resolved[1] = '\0';
+               if (path[1] == '\0')
+                       return (resolved);
+               resolved_len = 1;
+               left_len = my_strlcpy(left, path + 1, sizeof(left));
+       } else {
+               if (getcwd(resolved, MAXPATHLEN) == NULL) {
+                       my_strlcpy(resolved, ".", MAXPATHLEN);
                return (NULL);
        }
-#else
-       char wd[MAXPATHLEN];
-
-       if (getcwd(wd, MAXPATHLEN - 1) == NULL) {
-               (void)strcpy(resolved, ".");
+               resolved_len = strlen(resolved);
+               left_len = my_strlcpy(left, path, sizeof(left));
+       }
+       if (left_len >= sizeof(left) || resolved_len >= MAXPATHLEN) {
+               errno = ENAMETOOLONG;
                return (NULL);
        }
-#endif
 
        /*
-        * Find the dirname and basename from the path to be resolved.
-        * Change directory to the dirname component.
-        * lstat the basename part.
-        *     if it is a symlink, read in the value and loop.
-        *     if it is a directory, then change to that directory.
-        * get the current directory name and append the basename.
+        * Iterate over path components in `left'.
         */
-       (void)strncpy(resolved, path, MAXPATHLEN - 1);
-       resolved[MAXPATHLEN - 1] = '\0';
-loop:
-       q = strrchr(resolved, '/');
-       if (q != NULL) {
-               const char *dir;
-               p = q + 1;
-               if (q == resolved)
-                       dir = "/";
-               else {
-                       do {
-                               --q;
-                       } while (q > resolved && *q == '/');
-                       q[1] = '\0';
-                       dir = resolved;
-               }
-               if (chdir(dir) < 0)
-                       goto err1;
-       } else
-               p = resolved;
-
-#if defined(HAS_LSTAT) && defined(HAS_READLINK) && defined(HAS_SYMLINK)
-    {
-       struct stat sb;
-       /* Deal with the last component. */
-       if (lstat(p, &sb) == 0) {
-               if (S_ISLNK(sb.st_mode)) {
-                       int n;
-                       if (++symlinks > MAXSYMLINKS) {
-                               errno = ELOOP;
-                               goto err1;
+       while (left_len != 0) {
+               /*
+                * Extract the next path component and adjust `left'
+                * and its length.
+                */
+               p = strchr(left, '/');
+               s = p ? p : left + left_len;
+               if (s - left >= sizeof(next_token)) {
+                       errno = ENAMETOOLONG;
+                       return (NULL);
                        }
-                       n = readlink(p, resolved, MAXPATHLEN-1);
-                       if (n < 0)
-                               goto err1;
-                       resolved[n] = '\0';
-                       goto loop;
-               }
-               if (S_ISDIR(sb.st_mode)) {
-                       if (chdir(p) < 0)
-                               goto err1;
-                       p = "";
+               memcpy(next_token, left, s - left);
+               next_token[s - left] = '\0';
+               left_len -= s - left;
+               if (p != NULL)
+                       memmove(left, s + 1, left_len + 1);
+               if (resolved[resolved_len - 1] != '/') {
+                       if (resolved_len + 1 >= MAXPATHLEN) {
+                               errno = ENAMETOOLONG;
+                               return (NULL);
                }
+                       resolved[resolved_len++] = '/';
+                       resolved[resolved_len] = '\0';
        }
+               if (next_token[0] == '\0')
+                       continue;
+               else if (strcmp(next_token, ".") == 0)
+                       continue;
+               else if (strcmp(next_token, "..") == 0) {
+                       /*
+                        * Strip the last path component except when we have
+                        * single "/"
+                        */
+                       if (resolved_len > 1) {
+                               resolved[resolved_len - 1] = '\0';
+                               q = strrchr(resolved, '/') + 1;
+                               *q = '\0';
+                               resolved_len = q - resolved;
+                       }
+                       continue;
     }
-#endif
 
        /*
-        * Save the last component name and get the full pathname of
-        * the current directory.
+                * Append the next path component and lstat() it. If
+                * lstat() fails we still can return successfully if
+                * there are no more path components left.
         */
-       (void)strcpy(wbuf, p);
-       if (getcwd(resolved, MAXPATHLEN) == 0)
-               goto err1;
+               resolved_len = my_strlcat(resolved, next_token, MAXPATHLEN);
+               if (resolved_len >= MAXPATHLEN) {
+                       errno = ENAMETOOLONG;
+                       return (NULL);
+               }
+       #if defined(HAS_LSTAT) && defined(HAS_READLINK) && defined(HAS_SYMLINK)
+               {
+                       struct stat sb;
+                       if (lstat(resolved, &sb) != 0) {
+                               if (errno == ENOENT && p == NULL) {
+                                       errno = serrno;
+                                       return (resolved);
+                               }
+                               return (NULL);
+                       }
+                       if (S_ISLNK(sb.st_mode)) {
+                               int slen;
+                               
+                               if (symlinks++ > MAXSYMLINKS) {
+                                       errno = ELOOP;
+                                       return (NULL);
+                               }
+                               slen = readlink(resolved, symlink, sizeof(symlink) - 1);
+                               if (slen < 0)
+                                       return (NULL);
+                               symlink[slen] = '\0';
+                               if (symlink[0] == '/') {
+                                       resolved[1] = 0;
+                                       resolved_len = 1;
+                               } else if (resolved_len > 1) {
+                                       /* Strip the last path component. */
+                                       resolved[resolved_len - 1] = '\0';
+                                       q = strrchr(resolved, '/') + 1;
+                                       *q = '\0';
+                                       resolved_len = q - resolved;
+                               }
 
        /*
-        * Join the two strings together, ensuring that the right thing
-        * happens if the last component is empty, or the dirname is root.
+                                * If there are any path components left, then
+                                * append them to symlink. The result is placed
+                                * in `left'.
         */
-       if (resolved[0] == '/' && resolved[1] == '\0')
-               rootd = 1;
-       else
-               rootd = 0;
-
-       if (*wbuf) {
-               if (strlen(resolved) + strlen(wbuf) + (1 - rootd) + 1 > MAXPATHLEN) {
+                               if (p != NULL) {
+                                       if (symlink[slen - 1] != '/') {
+                                               if (slen + 1 >= sizeof(symlink)) {
                        errno = ENAMETOOLONG;
-                       goto err1;
+                                                       return (NULL);
                }
-               if (rootd == 0)
-                       (void)strcat(resolved, "/");
-               (void)strcat(resolved, wbuf);
+                                               symlink[slen] = '/';
+                                               symlink[slen + 1] = 0;
        }
-
-       /* Go back to where we came from. */
-#ifdef HAS_FCHDIR
-       if (fchdir(fd) < 0) {
-               serrno = errno;
-               goto err2;
+                                       left_len = my_strlcat(symlink, left, sizeof(left));
+                                       if (left_len >= sizeof(left)) {
+                                               errno = ENAMETOOLONG;
+                                               return (NULL);
        }
-#else
-       if (chdir(wd) < 0) {
-               serrno = errno;
-               goto err2;
        }
-#endif
+                               left_len = my_strlcpy(left, symlink, sizeof(left));
+                       }
+               }
+       #endif
+       }
 
-       /* It's okay if the close fails, what's an fd more or less? */
-#ifdef HAS_FCHDIR
-       (void)close(fd);
-#endif
+       /*
+        * Remove trailing slash except when the resolved pathname
+        * is a single "/".
+        */
+       if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
+               resolved[resolved_len - 1] = '\0';
        return (resolved);
-
-err1:  serrno = errno;
-#ifdef HAS_FCHDIR
-       (void)fchdir(fd);
-#else
-       (void)chdir(wd);
-#endif
-
-err2:
-#ifdef HAS_FCHDIR
-       (void)close(fd);
-#endif
-       errno = serrno;
-       return (NULL);
 #endif
 }