Re: [Bug-tar] Weird attitude when update flag is used

[Sergey Poznyakoff]

=?UTF-8?B?T3phbiDDh2HEn2xheWFu?= <address@hidden> ha escrit:

> When you try to update a tar archive which doesn't exist, tar exits with 
> an error :

Thanks for reporting.  I have installed the following fix:

Index: src/buffer.c
===================================================================
RCS file: /cvsroot/tar/tar/src/buffer.c,v
retrieving revision 1.115
diff -p -u -r1.115 buffer.c
--- src/buffer.c        31 Oct 2007 13:10:55 -0000      1.115
+++ src/buffer.c        5 Dec 2007 09:43:00 -0000
@@ -229,19 +229,21 @@ static struct zip_magic const magic[] = 
 
 /* Check if the file ARCHIVE is a compressed archive. */
 enum compress_type
-check_compressed_archive ()
+check_compressed_archive (bool *pshort)
 {
   struct zip_magic const *p;
   bool sfr;
-  bool short_file = false;
+  bool temp;
+
+  if (!pshort)
+    pshort = &temp;
   
   /* Prepare global data needed for find_next_block: */
   record_end = record_start; /* set up for 1st record = # 0 */
   sfr = read_full_records;
   read_full_records = true; /* Suppress fatal error on reading a partial
                               record */
-  if (find_next_block () == 0)
-    short_file = true;
+  *pshort = find_next_block () == 0;
   
   /* Restore global values */
   read_full_records = sfr;
@@ -254,9 +256,6 @@ check_compressed_archive ()
     if (memcmp (record_start->buffer, p->magic, p->length) == 0)
       return p->type;
 
-  if (short_file)
-    ERROR ((0, 0, _("This does not look like a tar archive")));
-
   return ct_none;
 }
 
@@ -273,11 +272,16 @@ open_compressed_archive ()
 
   if (!multi_volume_option)
     {
-      enum compress_type type = check_compressed_archive ();
+      bool shortfile;
+      enum compress_type type = check_compressed_archive (&shortfile);
 
       if (type == ct_none)
-       return archive;
-
+       {
+         if (shortfile)
+           ERROR ((0, 0, _("This does not look like a tar archive")));
+         return archive;
+       }
+      
       /* FD is not needed any more */
       rmtclose (archive);
 
@@ -502,15 +506,18 @@ _open_archive (enum access_mode wanted_a
        {
        case ACCESS_READ:
          {
+           bool shortfile;
            enum compress_type type;
 
            archive = STDIN_FILENO;
 
-           type = check_compressed_archive ();
+           type = check_compressed_archive (&shortfile);
            if (type != ct_none)
              FATAL_ERROR ((0, 0,
                            _("Archive is compressed. Use %s option"),
                            compress_option (type)));
+           if (shortfile)
+             ERROR ((0, 0, _("This does not look like a tar archive")));
          }
          break;
 
@@ -554,7 +561,7 @@ _open_archive (enum access_mode wanted_a
                           O_RDWR | O_CREAT | O_BINARY,
                           MODE_RW, rsh_command_option);
 
-       if (check_compressed_archive () != ct_none)
+       if (check_compressed_archive (NULL) != ct_none)
          FATAL_ERROR ((0, 0,
                        _("Cannot update compressed archives")));
        break;