Read POSIX multivolume archives split at the header boundary.

[chaz/tar] / src / buffer.c

diff --git a/src/buffer.c b/src/buffer.c
index f419dd7bcb357232ca76f254a78417c0a6794142..b47b773ee8ea65c151db1fc8293e52ca8e58a433 100644 (file)
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1165,7 +1165,7 @@ read_header0 (struct tar_stat_info *info)
   enum read_header rc;
 
   tar_stat_init (info);
-  rc = read_header (&current_header, info, false);
+  rc = read_header (&current_header, info, read_header_auto);
   if (rc == HEADER_SUCCESS)
     {
       set_next_block_after (current_header);
@@ -1213,17 +1213,42 @@ try_new_volume ()
     {
     case XGLTYPE:
       {
-        if (!read_header0 (&dummy))
-          return false;
+       tar_stat_init (&dummy);
+       if (read_header (&header, &dummy, read_header_x_global)
+           != HEADER_SUCCESS_EXTENDED)
+         {
+           ERROR ((0, 0, _("This does not look like a tar archive")));
+           return false;
+         }
+       
         xheader_decode (&dummy); /* decodes values from the global header */
         tar_stat_destroy (&dummy);
-        if (!real_s_name)
-          {
-            /* We have read the extended header of the first member in
-               this volume. Put it back, so next read_header works as
-               expected. */
-            current_block = record_start;
-          }
+       
+       /* The initial global header must be immediately followed by
+          an extended PAX header for the first member in this volume.
+          However, in some cases tar may split volumes in the middle
+          of a PAX header. This is incorrect, and should be fixed
+           in the future versions. In the meantime we must be
+          prepared to correctly list and extract such archives.
+
+          If this happens, the following call to read_header returns
+          HEADER_FAILURE, which is ignored.
+
+          See also tests/multiv07.at */
+              
+       switch (read_header (&header, &dummy, read_header_auto))
+         {
+         case HEADER_SUCCESS:
+           set_next_block_after (header);
+           break;
+
+         case HEADER_FAILURE:
+           break;
+
+         default:
+           ERROR ((0, 0, _("This does not look like a tar archive")));
+           return false;
+         }
         break;
       }