X-Git-Url: https://git.brokenzipper.com/gitweb?a=blobdiff_plain;ds=sidebyside;f=src%2Fbuffer.c;h=61310381e88e1a8370431bd18e20cd79a7f56d5d;hb=9a3e8a6f4374901c386821a0e08184f369141df4;hp=ed7530342398c15f316c3c2e372db25a3c81a7f3;hpb=166b7c7d028c3dbcfded5c834b9bf752d2fb41f0;p=chaz%2Ftar

diff --git a/src/buffer.c b/src/buffer.c
index ed75303..6131038 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -36,9 +36,6 @@
 /* Number of retries before giving up on read.  */
 #define READ_ERROR_MAX 10
 
-/* Globbing pattern to append to volume label if initial match failed.  */
-#define VOLUME_LABEL_APPEND " Volume [1-9]*"
-
 /* Variables.  */
 
 static tarlong prev_written;    /* bytes written on previous volumes */
@@ -857,16 +854,16 @@ seek_archive (off_t size)
   off_t start = current_block_ordinal ();
   off_t offset;
   off_t nrec, nblk;
-  off_t skipped = (blocking_factor - (current_block - record_start));
-
-  size -= skipped * BLOCKSIZE;
+  off_t skipped = (blocking_factor - (current_block - record_start))
+                  * BLOCKSIZE;
 
-  if (size < record_size)
+  if (size <= skipped)
     return 0;
-  /* FIXME: flush? */
-
+  
   /* Compute number of records to skip */
-  nrec = size / record_size;
+  nrec = (size - skipped) / record_size;
+  if (nrec == 0)
+    return 0;
   offset = rmtlseek (archive, nrec * record_size, SEEK_CUR);
   if (offset < 0)
     return offset;
@@ -1168,7 +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);
@@ -1216,17 +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;
       }
 
@@ -1313,6 +1335,35 @@ try_new_volume ()
 }
 
 
+#define VOLUME_TEXT " Volume "
+#define VOLUME_TEXT_LEN (sizeof VOLUME_TEXT - 1)
+
+char *
+drop_volume_label_suffix (const char *label)
+{
+  const char *p;
+  size_t len = strlen (label);
+
+  if (len < 1)
+    return NULL;
+  
+  for (p = label + len - 1; p > label && isdigit ((unsigned char) *p); p--)
+    ;
+  if (p > label && p - (VOLUME_TEXT_LEN - 1) > label)
+    {
+      p -= VOLUME_TEXT_LEN - 1;
+      if (memcmp (p, VOLUME_TEXT, VOLUME_TEXT_LEN) == 0)
+	{
+	  char *s = xmalloc ((len = p - label) + 1);
+	  memcpy (s, label, len);
+	  s[len] = 0;
+	  return s;
+	}
+    }
+
+  return NULL;
+}
+      
 /* Check LABEL against the volume label, seen as a globbing
    pattern.  Return true if the pattern matches.  In case of failure,
    retry matching a volume sequence number before giving up in
@@ -1329,12 +1380,12 @@ check_label_pattern (const char *label)
   if (!multi_volume_option)
     return false;
 
-  string = xmalloc (strlen (volume_label_option)
-                    + sizeof VOLUME_LABEL_APPEND + 1);
-  strcpy (string, volume_label_option);
-  strcat (string, VOLUME_LABEL_APPEND);
-  result = fnmatch (string, label, 0) == 0;
-  free (string);
+  string = drop_volume_label_suffix (label);
+  if (string)
+    {
+      result = fnmatch (string, volume_label_option, 0) == 0;
+      free (string);
+    }
   return result;
 }