Bug 750336

Summary: RFE: add wrapper executable package for 2.6 personality feature
Product: Red Hat Enterprise MRG Reporter: Clark Williams <williams>
Component: realtime-utilitiesAssignee: Clark Williams <williams>
Status: CLOSED ERRATA QA Contact: David Sommerseth <davids>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 2.1CC: bhu, jkodak, jneedle, lgoncalv, ovasik
Target Milestone: 2.1   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Some applications use flawed versioning logic that cannot recognize new Linux kernel versions in the format of "3.x.y". As a workaround to this bug in external applications, the new uname26 utility has been added to MRG Realtime 2.1 kernel. This utility activates the 2.6 personality kernel patch to transform data returned by the uname(2) system call to the format of "2.6.40.[minor_release_number]", and then executes the actual application. (BZ#750336)
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-01-23 17:57:20 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 749575    
Bug Blocks:    
Attachments:
Description Flags
source code for uname26 wrapper program none

Description Clark Williams 2011-10-31 18:36:41 UTC
Description of problem:

Some applications cannot deal with a Linux kernel version of the form 3.x.y. A 2.6 personality patch has been added to the MRG Realtime kernel which alters the data returned by the uname(2) system call, such that the the revision string gets transformed to:

         2.6.40 + (minor release number)

Using the personality patch, a process running on a 3.1.0 kernel would get a uname -r report of:

         2.6.41

Activating the personality patch requires a wrapper program that calls into the kernel to turn on the 2.6 personality, then execs the actual application. An upstream wrapper executable has been created named uname26.c. This BZ is a request to package uname26 for inclusion with the MRG 2.1 release (for use by the MRG realtime kernel). 

The source for uname26.c is attached.

Comment 1 Clark Williams 2011-10-31 18:38:38 UTC
Created attachment 531013 [details]
source code for uname26 wrapper program

Comment 3 David Sommerseth 2011-11-09 21:27:13 UTC
Verified in bug #749575

Comment 4 Beth Uptagrafft 2011-12-02 14:55:01 UTC
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Some applications use flawed versioning logic that cannot recognize new Linux kernel versions in the format of "3.x.y". As a workaround to this bug in external applications, the new uname26 utility has been added to MRG Realtime 2.1 kernel. This utility activates the 2.6 personality kernel patch to transform data returned by the uname(2) system call to the format of "2.6.40.[minor_release_number]", and then executes the actual application. (BZ#750336)

Comment 5 Clark Williams 2011-12-02 15:22:51 UTC
(In reply to comment #4)
. This utility activates the 2.6 personality kernel patch to
> transform data returned by the uname(2) system call to the format of
> "2.6.40.[minor_release_number]", and then executes the actual application.
> (BZ#750336)

More correctly, it returns a version of the form:

     2.6.40 + minor_release_number

so a 3.0 kernel becomes 2.6.40, a 3.1 kernel becomes 2.6.41, a 3.2 kernel becomes 2.6.42, etc.

Comment 6 errata-xmlrpc 2012-01-23 17:57:20 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHEA-2012-0047.html