delorie.com/archives/browse.cgi   search  
Mail Archives: djgpp/2015/12/28/21:23:21

X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f
Message-Id: <201512290222.tBT2MwNi009221@delorie.com>
Date: Tue, 29 Dec 2015 01:51:51 +0100
From: "Juan Manuel Guerrero (juan DOT guerrero AT gmx DOT de) [via djgpp-announce AT delorie DOT com]" <djgpp-announce AT delorie DOT com>
To: djgpp-announce AT delorie DOT com
Subject: ANNOUNCE: DJGPP port of GNU patch 2.7.5 uploaded.
Reply-To: djgpp AT delorie DOT com

This is a port of GNU patch 2.7.5 to MSDOS/DJGPP.

   GNU patch is a program to apply patches to files.  It accepts a "patch script",
   usually produced by file-comparison utility such as Diff, and produces
   modified files by applying this script to old versions of files.

   More often than not, Patch is used with text, usually source, files.
   But it can also patch binary files, although the patch scripts for binary
   files tend to be large.



   DJGPP specific changes.
   =======================

   The port offers the same djgpp specific functionality than the previous
   port.  These are:
   - support for numbered backups even on 8+3 file systems;

   - Patch can now ignore the CR characters at the end of each line
     of the patch script, so patching Unix-style text files does not
     convert them to DOS-style files anymore (if you use the --binary
     switch).

   To build this port you will need:
   - to have an OS with LFN support to configure and compile the source
     package.  I have no plans to support SFN systems to build the patch
     binaries.
   - to run the test suite you will need to install the latest mktmpNNb.zip


   As usual, all djgpp specific files (config.bat, diffs, README files, etc.)
   are stored in the /djgpp directory.

   Please note that there is a directory called /pc/djgpp that contains files
   that are part of the official FSF patch distribution.  I have inspected those
   files but I have never used them nor I have plans to change this in the future.
   Due to the massive use of gnulib code it is no longer possible to compile the
   official FSF distribution out-of-the-box.  So I will neither try to use those
   files nor to keep them up to date.  I will only use my own ones.  If someone
   else would like to keep those files up to date it will be OK with me.

   Please also note that some of the tests of the test suite will fail.  This is
   not a port issue but a test suite issue.  The test suite is very posix centric
   so that some test will fail in an environment like DOS/Windows.  The most
   notorious test to fail is crlf-handling.  Here the behaviour of patch in a
   posix environment is tested and how it works when files to patch or the diffs
   file has DOS style EOL.  This is not the same behaviour than a DOS/DJGPP port
   of patch to work in a DOS/WINDOWS environment.  Not all those test will fail
   but some of them.  It makes no sense to try to adjust them because they test
   for a behaviour that the port will not offer.  Other tests that will fully
   or  partially fail are preserve-mode-and-timestamp, file-modes and fifo.

   One of the most notorious change between this patch version and the previous
   one is that this one uses a hash table to administrate the names of the files
   it wants to modify or create.  The hash keys are created using the st_dev and
   st_ino values.  Especially DJGPP creates the st_ino value using the starting
   cluster of the file.  This has the consequence that every time the file is
   changed by the patch program by appending some new contents it gets a new
   st_ino.  This has the consequence that stat()ing again produces a different
   st_ino for the same file and indeed a new hash key that makes it impossible
   to find the already existing entry for this file in the hash table.  This has
   the nasty consequence, that when patch appends something new to this file, it
   does not see that the file already exists and instead of appending to it, it
   creates a new one at the same location with the same name overwriting the old
   one with the new contains.  To solve this issue it was necessary to create
   unique and persistent inode numbers for every file produced by patch.
   Wrapper functions to stat, fstat, open, fopen, close and fclose have been
   written that will keep in sync file name, file descriptor and invented inode
   number for every file produced by patch.  See /pc/pc_inode.c for details
   concerning the implementation.

   Another change is that the patch program relaies on some explicit values of
   the file type bits stored in the st_mode member of stat.  Especially it is
   assumed that every S_IF* bit is encoded by 1 and not by 0.  But unfortunately
   this is the case in DJGPP.  DJGPP encodes S_IFREG with zero.  This makes the
   code fail.  To avoid to have to change alot of code lines, S_IFREG is mapped
   to another value different from zero before used.

   This port supports git-style of patch files.  Unfortunately this type of
   patches encode the file type (like regular file or symlink) of the files
   to be patched as number in the header of the patch file.  This means that
   the patch program reads a git-style patch file and parses the header and
   tries to determinate if the file to be patched will be a regular file
   (S_IFREG) or a symlink (S_IFLNK) or something else.  This means that the
   values of S_IFREG or S_IFLNK are not stored as some kind of symbols but as
   those real numbers used to encode them on the OS where the patch file has
   been produced.  This has the consequence that if on a different OS/compiler
   this encoding does not match, the patch program will not work properly.  An
   inspection of sys/stat.h of linux, bsd and cygwin shows that they all use
   the same encodings for all values stored in the st_mode member of the stat
   structure.  Unfortunately DJGPP encodes these values in an incompatible way.
   When this port parses that file type number, it _ALWAYS_ interprets it as
   linux/bsd/cygwin encoding of the S_IF* bits and maps it to the DJGPP specifc
   values of those bits.  Please note, that the port has no way to determinate
   if the number really represents linux/bsd/cygwin encoding or not.  If the
   number is not a linux/bsd/cygwin encoding, the mapping will fail an the
   patch cannot be applied.  The port assumes that the following encoding for
   the S_IF* bits is valid:
     /* Encoding of the file mode.  */

     #define S_IFMT    0170000  /* These bits determine file type.  */

     /* File types.  */
     #define S_IFDIR   0040000  /* Directory.  */
     #define S_IFCHR   0020000  /* Character device.  */
     #define S_IFBLK   0060000  /* Block device.  */
     #define S_IFREG   0100000  /* Regular file.  */
     #define S_IFIFO   0010000  /* FIFO.  */
     #define S_IFLNK   0120000  /* Symbolic link.  */
     #define S_IFSOCK  0140000  /* Socket.  */
   If this assumption is not true, the mapping to DJGPP values of S_IF* bits
   will fail.

   Please note that the FSF distribution of patch no longer can be compiled with
   DJGPP out-of-the-box.  If something seems not to work with this port, please
   report it first at c.o.m.d. and not at bug-patch AT gnu DOT org.  The maintainer
   will have no idea about what I have done.

   The source package is configured to be build in the "_build" directory.

   The DJGPP 2.05 version of the port has been compiled using gcc530 and bnu225br2.

   The port has been configured and compiled on WinXP SP3.  There is no guarantee
   that this may be possible with any other DOS-like OS.  Due to the use of long
   file names it will not be possible to configure and compile without LFN support.



   For further information about GNU patch please read the info docs and NEWS
   file.


   Here is an extract of the NEWS file showing the user visible changes from
   the last port (GNU patch 2.7.1) to this one:

-------------------------------------------------------------------------------

Changes in version 2.7.5:

* There are users which expect patch to follow symbolic links in the working
   directory, so patch now again follows symbolic links as long as they do not
   leave the working directory.

Changes until version 2.7.4:

* When a file isn't being deleted because the file contents don't match the
   patch, the resulting message is now "Not deleting file ... as content
   differs from patch" instead of "File ... is not empty after patch; not
   deleting".
* Function names in hunks (from diff -p) are now preserved in reject files.
* Patch no longer follows symbolic links to input and output files.  This
   ensures that symbolic links created by git-style patches cannot cause
   patch to write outside the working directory (CVE-2015-1196).
* Various fixes.

-------------------------------------------------------------------------------




   The port consists of the usual two packages produced using djdev205
   that can be downloaded from ftp.delorie.com and mirrors as (time stamp 2015-12-24):

     Patch 2.7.5 binary and man format documentation:
     ftp://ftp.delorie.com/pub/djgpp/beta/v2gnu/pat275b.zip

     Patch 2.7.5 source:
     ftp://ftp.delorie.com/pub/djgpp/beta/v2gnu/pat275s.zip



   Send Patch specific bug reports to <bug-patch AT gnu DOT org>.
   Send suggestions and bug reports concerning the DJGPP port
   to comp.os.msdos.djgpp or <djgpp AT delorie DOT com>.

Enjoy.

       Guerrero, Juan Manuel <juan DOT guerrero AT gmx DOT de>

- Raw text -


  webmaster     delorie software   privacy  
  Copyright © 2019   by DJ Delorie     Updated Jul 2019