Re: [Bug-tar] bug tar

[Sergey Poznyakoff]

Hi Thomas,

Thank you for writing to the list:^) 

> tar --strip-components=100   -xvf 000.tar
>  no warning/error code is given when nothing happend

It is perfectly normal if --strip-components results in
some or all member names being reduced to empty strings and therefore
not extracted. There's nothing to warn about in this case.

>  tar hangs:

This has already been fixed. See commit b60e56fd.

> ### start: critical error
> $ tar -rf no_tar_file dir
> tar: This does not look like a tar archive
> tar: Skipping to next header
> tar: Exiting with failure status due to previous errors
> 
> But it appends to ... (no_tar_file was > 512 bytes)

That's a bug indeed. A patch is attached.

> tar -cf some.tar dir -V "/"
> tar -tvf some.tar
> tarr: Removing leading `/' from member names
> 
> tar -xvf some.tar
> tarr: Removing leading `/' from member names
> 
>  it's only the volume ;-))

A patch is attached.

Regards,
Sergey

>From 5aa7046f1de9e27bfd57c583aff647c348a47285 Mon Sep 17 00:00:00 2001
From: Sergey Poznyakoff <address@hidden>
Date: Sun, 22 Aug 2010 05:08:56 +0300
Subject: [PATCH] Safety checking in update mode.

* src/tar.c (decode_options): Display a usage error if one of
-Aru is used, but no file list is given.
* src/update.c (update_archive): Don't write end-of-archive
marker if nothing was appended to it.
Exit with error if the archive is not a valid tar one.
---
 src/tar.c    |    6 +++++-
 src/update.c |   12 ++++++++----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/tar.c b/src/tar.c
index 10ba8a9..5c2a617 100644
--- a/src/tar.c
+++ b/src/tar.c
@@ -2512,13 +2512,17 @@ decode_options (int argc, char **argv)
     case CAT_SUBCOMMAND:
     case UPDATE_SUBCOMMAND:
     case APPEND_SUBCOMMAND:
+      if (!args.input_files && !files_from_option)
+       USAGE_ERROR ((0, 0,
+                     _("The %s option is meaningless without a file list"),
+                     subcommand_string (subcommand_option)));
       for (archive_name_cursor = archive_name_array;
           archive_name_cursor < archive_name_array + archive_names;
           archive_name_cursor++)
        if (!strcmp (*archive_name_cursor, "-"))
          USAGE_ERROR ((0, 0,
                        _("Options `-Aru' are incompatible with `-f -'")));
-
+      
     default:
       break;
     }
diff --git a/src/update.c b/src/update.c
index b015175..fe29bd4 100644
--- a/src/update.c
+++ b/src/update.c
@@ -107,7 +107,8 @@ update_archive (void)
 {
   enum read_header previous_status = HEADER_STILL_UNREAD;
   bool found_end = false;
-
+  bool updated_archive = false;
+  
   name_gather ();
   open_archive (ACCESS_UPDATE);
   buffer_write_global_xheader ();
@@ -186,8 +187,9 @@ update_archive (void)
          switch (previous_status)
            {
            case HEADER_STILL_UNREAD:
-             WARN ((0, 0, _("This does not look like a tar archive")));
-             /* Fall through.  */
+             ERROR ((0, 0, _("This does not look like a tar archive")));
+             close_archive ();
+             return;
 
            case HEADER_SUCCESS:
            case HEADER_ZERO_BLOCK:
@@ -221,6 +223,7 @@ update_archive (void)
          continue;
        if (interactive_option && !confirm ("add", file_name))
          continue;
+       updated_archive = true;
        if (subcommand_option == CAT_SUBCOMMAND)
          append_file (file_name);
        else
@@ -228,7 +231,8 @@ update_archive (void)
       }
   }
 
-  write_eot ();
+  if (updated_archive)
+    write_eot ();
   close_archive ();
   names_notfound ();
 }
-- 
1.6.0.3

>From 1d039d692ec3f0bdf65563550a2848fd9ededb31 Mon Sep 17 00:00:00 2001
From: Sergey Poznyakoff <address@hidden>
Date: Sun, 22 Aug 2010 05:25:46 +0300
Subject: [PATCH] Don't apply file transformations to volume names.

* src/list.c (decode_header): Don't apply file transformations to volume names.
---
 src/list.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/src/list.c b/src/list.c
index 9184bea..60ce91f 100644
--- a/src/list.c
+++ b/src/list.c
@@ -642,6 +642,10 @@ decode_header (union block *header, struct tar_stat_info 
*stat_info,
        stat_info->is_dumpdir = true;
     }
 
+  if (header->header.typeflag == GNUTYPE_VOLHDR)
+    /* Name transformations don't apply to volume headers. */
+    return;
+  
   transform_member_name (&stat_info->file_name, XFORM_REGFILE);
   switch (header->header.typeflag)
     {
-- 
1.6.0.3