[PATCH] Tar with transformer (gzip, bzip2, ...) on NOMMU

[Denys Vlasenko]

On Wednesday 05 September 2007 12:12, Alex Landau wrote:
> The attached patch makes "tar -xzf" work on NOMMU.
> 
> - The main part is the open_transformer function that instead of forking and running a
> "transformation" function (that should decompress the archive), vforks and execs the
> appropriate decompressor.
> - A bit of preprocessor magic (include/unarchive.h) removes the unused arguments at the
> time of call (the transformer function is unused on NOMMU, and the external helper to
> exec is unused on MMU).
> - Changed components and how thorough they were tested:
>   * tar -xzf - fullly tested on MMU and NOMMU.
>   * tar -xjf - same.
>   * tar -xaf (LZMA) - same.
>   * LZMA (archival/bbunzip.c) - added -f option (same meaning as for gunzip).
>       It was present in the usage message, seems to be implemented by the
>       common function bbunpack(), but just was not passed to getopt32().
>   * tar -xZf (uncompress) - compile-tested only (both MMU and NOMMU).
>       I don't have .Z files to test on... Should work as long as uncompress can be
>       invoked as "uncompress -cf -".
>   * rpm - compile-tested on both MMU and NOMMU. Sort of runtime tested on MMU.
>       I downloaded an rpm file and ran ./busybox rpm -i <the-file>.rpm. It
>       complained that it can't create some file under /etc. That's normal since
>       I'm not root. The files it tried to create have the correct names, so it should
>       work (tm).
> - The patch should change nothing on MMU machines. Someone using rpm and compress, please
> verify that...
> - gzip, bzip2 and lzma work for me on NOMMU (and on MMU too, of course).
> - The patch touches quite a lot of files, but the changes are minor in most cases (except
> open_transformer that is at the core). Diffstat below.
> 
>  archival/bbunzip.c                          |    2 +-
>  archival/libunarchive/Kbuild                |    1 -
>  archival/libunarchive/get_header_tar_bz2.c  |    2 +-
>  archival/libunarchive/get_header_tar_gz.c   |    9 ++++++++-
>  archival/libunarchive/get_header_tar_lzma.c |    2 +-
>  archival/libunarchive/open_transformer.c    |   22 +++++++++++++++++++++-
>  archival/rpm.c                              |   26 +++++++++++++++++++++++---
>  archival/tar.c                              |    2 +-
>  include/unarchive.h                         |    6 ++++++
>  9 files changed, 62 insertions(+), 10 deletions(-)

Applied with very minor changes, many thanks!

(bloatcheck says 0 bytes difference for MMU)
--
vda