tar: fix bug with -C and delayed setting of metadata

* src/common.h (chdir_current): New decl.
* src/extract.c (struct delayed_set_stat, struct delayed_link):
New member change_dir.
(delay_set_stat, create_placeholder_file): Set it.
(apply_nonancestor_delayed_set_stat, apply_delayed_links): Use it.
(extract_link): Check that the links are all relative to the same
directory.
(extract_archive): Restore the current directory after
apply_nonancestor_delayed_set_stat has possibly changed it.
* src/misc.c (chdir_current): New external var; this used to
be the private static variable 'previous' inside chdir_dir.
All uses changed.
* tests/Makefile.am (TESTSUITE_AT): New test extrac10.at.
* tests/extrac10.at: New file.
* tests/testsuite.at: Include it.

src/common.h

@@ -603,6 +603,7 @@ void undo_last_backup (void);
 
 int deref_stat (bool deref, char const *name, struct stat *buf);
 
+extern int chdir_current;
 int chdir_arg (char const *dir);
 void chdir_do (int dir);
 int chdir_count (void);

src/extract.c

@@ -69,6 +69,7 @@ struct delayed_set_stat
     mode_t invert_permissions;
     enum permstatus permstatus;
     bool after_links;
+    int change_dir;
     char file_name[1];
   };
 
@@ -94,6 +95,9 @@ struct delayed_link
     uid_t uid;
     gid_t gid;
 
+    /* The directory that the sources and target are relative to.  */
+    int change_dir;
+
     /* A list of sources for this link.  The sources are all to be
        hard-linked together.  */
     struct string_list *sources;
@@ -373,6 +377,7 @@ delay_set_stat (char const *file_name, struct tar_stat_info const *st,
   data->invert_permissions = invert_permissions;
   data->permstatus = permstatus;
   data->after_links = 0;
+  data->change_dir = chdir_current;
   strcpy (data->file_name, file_name);
   delayed_set_stat_head = data;
 }
@@ -606,6 +611,8 @@ apply_nonancestor_delayed_set_stat (char const *file_name, bool after_links)
 	      && memcmp (file_name, data->file_name, data->file_name_len) == 0))
 	break;
 
+      chdir_do (data->change_dir);
+
       if (check_for_renamed_directories)
 	{
 	  cur_info = &st;
@@ -933,6 +940,7 @@ create_placeholder_file (char *file_name, bool is_symlink, bool *interdir_made)
 	  p->uid = current_stat_info.stat.st_uid;
 	  p->gid = current_stat_info.stat.st_gid;
 	}
+      p->change_dir = chdir_current;
       p->sources = xmalloc (offsetof (struct string_list, string)
 			    + strlen (file_name) + 1);
       p->sources->next = 0;
@@ -990,7 +998,8 @@ extract_link (char *file_name, int typeflag)
 	  struct delayed_link *ds = delayed_link_head;
 	  if (ds && lstat (link_name, &st1) == 0)
 	    for (; ds; ds = ds->next)
-	      if (ds->dev == st1.st_dev
+	      if (ds->change_dir == chdir_current
+		  && ds->dev == st1.st_dev
 		  && ds->ino == st1.st_ino
 		  && timespec_cmp (ds->ctime, get_stat_ctime (&st1)) == 0)
 		{
@@ -1297,7 +1306,11 @@ extract_archive (void)
      it is an incremental archive.
      (see NOTICE in the comment to delay_set_stat above) */
   if (!delay_directory_restore_option)
-    apply_nonancestor_delayed_set_stat (current_stat_info.file_name, 0);
+    {
+      int dir = chdir_current;
+      apply_nonancestor_delayed_set_stat (current_stat_info.file_name, 0);
+      chdir_do (dir);
+    }
 
   /* Take a safety backup of a previously existing file.  */
 
@@ -1327,7 +1340,7 @@ extract_archive (void)
 
 }
 
-/* Extract the symbolic links whose final extraction were delayed.  */
+/* Extract the links whose final extraction were delayed.  */
 static void
 apply_delayed_links (void)
 {
@@ -1338,6 +1351,8 @@ apply_delayed_links (void)
       struct string_list *sources = ds->sources;
       char const *valid_source = 0;
 
+      chdir_do (ds->change_dir);
+
       for (sources = ds->sources; sources; sources = sources->next)
 	{
 	  char const *source = sources->string;

src/misc.c

@@ -712,16 +712,17 @@ chdir_arg (char const *dir)
   return wd_count++;
 }
 
+/* Index of current directory.  */
+int chdir_current;
+
 /* Change to directory I.  If I is 0, change to the initial working
    directory; otherwise, I must be a value returned by chdir_arg.  */
 void
 chdir_do (int i)
 {
-  static int previous;
-
-  if (previous != i)
+  if (chdir_current != i)
     {
-      struct wd *prev = &wd[previous];
+      struct wd *prev = &wd[chdir_current];
       struct wd *curr = &wd[i];
 
       if (prev->err < 0)
@@ -766,7 +767,7 @@ chdir_do (int i)
 	    chdir_fatal (curr->name);
 	}
 
-      previous = i;
+      chdir_current = i;
     }
 }