Bug 594536

Summary: Extra fork when tcsh processes backquotes
Product: Red Hat Enterprise Linux 5 Reporter: Bryan Mason <bmason>
Component: tcshAssignee: Jaromír Končický <jkoncick>
Status: CLOSED CURRENTRELEASE QA Contact: BaseOS QE - Apps <qe-baseos-apps>
Severity: high Docs Contact:
Priority: high    
Version: 5.5CC: bnater, ovasik, pbatkowski, rbinkhor, rvokal, tao
Target Milestone: rcKeywords: Patch, ZStream
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
: 689383 (view as bug list) Environment:
Last Closed: 2013-09-23 11:04:39 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 640251, 673556, 688170, 689383    
Attachments:
Description Flags
Proposed Patch none

Description Bryan Mason 2010-05-20 23:42:51 UTC 
Description of problem:

    When tcsh-6.14 performs command substitution within backquotes, an
    extra fork() is performed.  this can cause issues when a command
    run within the backquotes wants to find the PID of the main tcsh
    process from which it was fork()ed.

Version-Release number of selected component (if applicable):

    tcsh-6.14-17.el5

How reproducible:

    100%

Steps to Reproduce:

    1. Run "echo `pstree -p $$`"
  
Actual results:

    tcsh(4343)---tcsh(4344)---pstree(4345)

    (note that tcsh forks twice)
    
Expected results:

    tcsh(4346)---pstree(4347)

    (note that tcsh only forks once to run pstree)

Additional info:

    This has been reported and accepted upstream:

        http://mx.gw.com/pipermail/tcsh-bugs/2010-May/000679.html

    This was not a problem with tcsh-6.13
Comment 1 Bryan Mason 2010-05-20 23:45:07 UTC 
Created attachment 415541 [details]
Proposed Patch

This patch assumes that the patch in Bug 531353 has already been applied.