tar: work around NetBSD and Tru64 symlink incompatibility with POSIX

[chaz/tar] / src / extract.c

diff --git a/src/extract.c b/src/extract.c
index 0a1a032989d3d59a1aeb989f3bd6a3fe08ea1422..aaea56ed3abcfcfb2bfde356715f6133e22e4fae 100644 (file)
--- a/src/extract.c
+++ b/src/extract.c
@@ -478,20 +478,20 @@ repair_delayed_set_stat (char const *dir,
 
 /* After a file/link/directory creation has failed, see if
    it's because some required directory was not present, and if so,
-   create all required directories.  Return non-zero if a directory
-   was created.  */
+   create all required directories.  Return zero if all the required
+   directories were created, nonzero (issuing a diagnostic) otherwise.
+   Set *INTERDIR_MADE if at least one directory was created.  */
 static int
-make_directories (char *file_name)
+make_directories (char *file_name, bool *interdir_made)
 {
   char *cursor0 = file_name + FILE_SYSTEM_PREFIX_LEN (file_name);
   char *cursor;                        /* points into the file name */
-  int did_something = 0;       /* did we do anything yet? */
-  int status;
 
   for (cursor = cursor0; *cursor; cursor++)
     {
       mode_t mode;
       mode_t desired_mode;
+      int status;
 
       if (! ISSLASH (*cursor))
        continue;
@@ -524,28 +524,32 @@ make_directories (char *file_name)
                          desired_mode, AT_SYMLINK_NOFOLLOW);
 
          print_for_mkdir (file_name, cursor - file_name, desired_mode);
-         did_something = 1;
-
-         *cursor = '/';
-         continue;
+         *interdir_made = true;
+       }
+      else if (errno == EEXIST)
+       status = 0;
+      else
+       {
+         /* Check whether the desired file exists.  Even when the
+            file exists, mkdir can fail with some errno value E other
+            than EEXIST, so long as E describes an error condition
+            that also applies.  */
+         int e = errno;
+         struct stat st;
+         status = fstatat (chdir_fd, file_name, &st, 0);
+         if (status)
+           {
+             errno = e;
+             mkdir_error (file_name);
+           }
        }
 
       *cursor = '/';
-
-      if (errno == EEXIST)
-       continue;               /* Directory already exists.  */
-      else if ((errno == ENOSYS /* Automounted dirs on Solaris return
-                                  this. Reported by Warren Hyde
-                                  <Warren.Hyde@motorola.com> */
-              || ERRNO_IS_EACCES)  /* Turbo C mkdir gives a funny errno.  */
-              && faccessat (chdir_fd, file_name, W_OK, AT_EACCESS) == 0)
-       continue;
-
-      /* Some other error in the mkdir.  We return to the caller.  */
-      break;
+      if (status)
+       return status;
     }
 
-  return did_something;                /* tell them to retry if we made one */
+  return 0;
 }
 
 /* Return true if FILE_NAME (with status *STP, if STP) is not a
@@ -605,6 +609,18 @@ maybe_recoverable (char *file_name, bool regular, bool *interdir_made)
   switch (e)
     {
     case ELOOP:
+
+      /* With open ("symlink", O_NOFOLLOW|...), POSIX says errno == ELOOP,
+        but some operating systems do not conform to the standard.  */
+#ifdef EFTYPE
+      /* NetBSD uses errno == EFTYPE; see <http://gnats.netbsd.org/43154>.  */
+    case EFTYPE:
+#endif
+      /* FreeBSD 8.1 uses errno == EMLINK.  */
+    case EMLINK:
+      /* Tru64 5.1B uses errno == ENOTSUP.  */
+    case ENOTSUP:
+
       if (! regular
          || old_files_option != OVERWRITE_OLD_FILES || dereference_option)
        break;
@@ -644,11 +660,8 @@ maybe_recoverable (char *file_name, bool regular, bool *interdir_made)
 
     case ENOENT:
       /* Attempt creating missing intermediate directories.  */
-      if (make_directories (file_name))
-       {
-         *interdir_made = true;
-         return RECOVER_OK;
-       }
+      if (make_directories (file_name, interdir_made) == 0 && *interdir_made)
+       return RECOVER_OK;
       break;
 
     default:
@@ -776,7 +789,7 @@ extract_dir (char *file_name, int typeflag)
 
   for (;;)
     {
-      status = mkdir (file_name, mode);
+      status = mkdirat (chdir_fd, file_name, mode);
       if (status == 0)
        {
          current_mode = mode & ~ current_umask;
@@ -863,6 +876,20 @@ open_output_file (char const *file_name, int typeflag, mode_t mode,
        }
     }
 
+  /* If O_NOFOLLOW is needed but does not work, check for a symlink
+     separately.  There's a race condition, but that cannot be avoided
+     on hosts lacking O_NOFOLLOW.  */
+  if (! O_NOFOLLOW && overwriting_old_files && ! dereference_option)
+    {
+      struct stat st;
+      if (fstatat (chdir_fd, file_name, &st, AT_SYMLINK_NOFOLLOW) == 0
+         && S_ISLNK (st.st_mode))
+       {
+         errno = ELOOP;
+         return -1;
+       }
+    }
+
   fd = openat (chdir_fd, file_name, openflag, mode);
   if (0 <= fd)
     {
@@ -1190,7 +1217,7 @@ static int
 extract_node (char *file_name, int typeflag)
 {
   bool interdir_made = false;
-  mode_t mode = (current_stat_info.stat.st_mode & MODE_RWX
+  mode_t mode = (current_stat_info.stat.st_mode & (MODE_RWX | S_IFBLK | S_IFCHR)
                 & ~ (0 < same_owner_option ? S_IRWXG | S_IRWXO : 0));
 
   while (mknodat (chdir_fd, file_name, mode, current_stat_info.stat.st_rdev)
@@ -1544,11 +1571,12 @@ rename_directory (char *src, char *dst)
   if (renameat (chdir_fd, src, chdir_fd, dst) != 0)
     {
       int e = errno;
+      bool interdir_made;
 
       switch (e)
        {
        case ENOENT:
-         if (make_directories (dst))
+         if (make_directories (dst, &interdir_made) == 0)
            {
              if (renameat (chdir_fd, src, chdir_fd, dst) == 0)
                return true;