Patch Name: PHCO_26907

Patch Description: s700_800 11.11 diff(1) patch

Creation Date: 02/06/17

Post Date:  02/06/20

Hardware Platforms - OS Releases:
	s700: 11.11
	s800: 11.11

Products: N/A

Filesets:
	OS-Core.CMDS-AUX,fr=B.11.11,fa=HP-UX_B.11.11_32/64,v=HP

Automatic Reboot?: No

Status: General Release

Critical: No

Category Tags:
	defect_repair general_release

Path Name: /hp-ux_patches/s700_800/11.X/PHCO_26907

Symptoms:
	PHCO_26907:
	( SR:8606254124 CR:JAGae18456 )
	diff(1) is not handling the incomplete/illegal multibyte
	characters properly in multibyte environment.

	( SR:8606192634 CR:JAGad61846 )
	diff(1) command  does not return the proper exit value when
	comparing sub-directories.

	( SR:8606251084 CR:JAGae17150 )
	diff(1) command in few cases does not report minimal
	results.

Defect Description:
	PHCO_26907:
	( SR:8606254124 CR:JAGae18456 )
	diff(1) command misbehaves in multi-byte environment for
	files containing invalid multi-byte characters. The problem
	can be reproduced as follows:

	- Generate a file(file1) with few invalid multi-byte
	characters.
	$cp file1 file2
	$export LANG=<Some multi-byte locale e.g. zh_CN.gb18030>
	$vi file2
	 :wq

	<Note that vi generates the message that this file has some
	 invalid multi-byte characters>

	 - ls -l file1 file2
	shows that files have different size.
	$diff file1 file2
	$
	Note that diff(1) should have shown the difference between
	the two files.
	$export LANG=C
	$diff file1 file2
	<shows the difference>
	$

	Resolution:
	In the multibyte environment, while comparing the two
	characters, diff(1) tries to match their wide character
	representation. Now along with this comparison, diff(1) also
	compares the validity of the two characters.

	( SR:8606192634 CR:JAGad61846 )
	diff(1) command returns wrong exit value in some cases when
	comparing the directories i.e. if the sub-directories of the
	two input directories differ, diff(1) command reports the
	correct differences, but it returns with an exit value "0".
	The expected(documented) behavior is to return with an exit
	value "1" for any differences (files, directories or sub
	directories).
	The problem can be reproduced as follows:

	$mkdir -p dir1/subdir1 dir2/subdir1
	$touch dir1/subdir1/file1
	$diff -r dir1 dir2
	Common subdirectories: dir1/subdir1 and dir2/subdir1
	Only in dir1/subdir1: file1
	$echo $?
	0          <--- This is wrong. Expected exit value is 1.
	$

	Resolution:
	Initially the status of child process was not properly
	trapped in the parent process. Now the code is modified to
	capture the exit status of the child process also. So if
	the subdirectories differ, then diff(1) will return with
	an exit value "1".

	( SR:8606251084 CR:JAGae17150 )
	diff(1) command for some files does not report minimal
	differences.
	The problem can be reproduced as follows:

	$cat file1
	12345678
	01081679
	$cat file2
	01081679
	$diff file1 file2
	1,2c1
	< 12345678
	< 01081679
	---
	> 01081679
	$

	The expected output is

	$diff file1 file2
	1d0
	< 12345678
	$

	diff(1) command uses the hashing algorithm to compare the
	files. A hash value is generated for each line in the two
	files specified. diff(1) used to generate 16 bit hashing
	values. Because of this, the possibilities of having hash
	collisions(having the same hash values for two different
	lines) were high. If mth line of file1 and nth line of file2
	computes to same hash value, then diff(1) assumes the two
	lines could be identical and hence applies the character-
	wise comparison on these two lines only. On finding them
	different, it just outputs them as the difference, without
	considering the situation that there could be an another
	line in file2 which is identical to mth line of file1. Hence
	diff(1) is not able to report minimal difference. The output
	differs depending on the ordering of lines in the input
	files.

	Resolution:
	The problem is addressed by modifying diff(1) command to
	generate 32bit hash values instead of 16bit values. This fix
	only minimizes the hash collisions. Even after this fix,
	there could be rare possibilities of getting hash value
	collisions in which case one could again see the command not
	generating minimal output.

SR:
	8606192634 8606251084 8606254124

Patch Files:
	
	OS-Core.CMDS-AUX,fr=B.11.11,fa=HP-UX_B.11.11_32/64,v=HP:
	/usr/bin/diff

what(1) Output:
	
	OS-Core.CMDS-AUX,fr=B.11.11,fa=HP-UX_B.11.11_32/64,v=HP:
	/usr/bin/diff:
		diff.c $Date: 2002/06/03 03:20:39 $Revision: r11.11/
			2 PATCH_11.11 (PHCO_26907)
		diffdir.c $Date: 2002/06/03 03:20:03 $Revision: r11.
			11/3 PATCH_11.11 (PHCO_26907)
		diffreg.c $Date: 2002/06/03 03:18:35 $Revision: r11.
			11/3 PATCH_11.11 (PHCO_26907)
		$Revision: @(#) diff CUP11.11_BL2002_0617_2 PATCH_11
			.11 PHCO_26907
		Mon Jun 17 05:04:06 PDT 2002 $

cksum(1) Output:
	
	OS-Core.CMDS-AUX,fr=B.11.11,fa=HP-UX_B.11.11_32/64,v=HP:
	2027264724 36864 /usr/bin/diff

Patch Conflicts: None

Patch Dependencies: None

Hardware Dependencies: None

Other Dependencies: None

Supersedes: None

Equivalent Patches:
	PHCO_27012:
	s700: 11.00
	s800: 11.00

Patch Package Size: 60 KBytes

Installation Instructions:
	Please review all instructions and the Hewlett-Packard
	SupportLine User Guide or your Hewlett-Packard support terms
	and conditions for precautions, scope of license,
	restrictions, and, limitation of liability and warranties,
	before installing this patch.
	------------------------------------------------------------
	1. Back up your system before installing a patch.

	2. Login as root.

	3. Copy the patch to the /tmp directory.

	4. Move to the /tmp directory and unshar the patch:

		cd /tmp
		sh PHCO_26907

	5. Run swinstall to install the patch:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -s /tmp/PHCO_26907.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/save/PHCO_26907.  If you do not wish to retain a
	copy of the original software, include the patch_save_files
	option in the swinstall command above:

		-x patch_save_files=false

	WARNING: If patch_save_files is false when a patch is installed,
		 the patch cannot be deinstalled.  Please be careful
		 when using this feature.

	For future reference, the contents of the PHCO_26907.text file is 
	available in the product readme:

		swlist -l product -a readme -d @ /tmp/PHCO_26907.depot

	To put this patch on a magnetic tape and install from the
	tape drive, use the command:

		dd if=/tmp/PHCO_26907.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions: None