Bug 429559

Summary:	Man page of "kill(1)" is missing a description of "kill -0" (and so does bash)
Product:	Red Hat Enterprise Linux 4	Reporter:	David Tonhofer <bughunt>
Component:	util-linux	Assignee:	Karel Zak <kzak>
Status:	CLOSED ERRATA	QA Contact:	Ben Levenson <benl>
Severity:	low	Docs Contact:
Priority:	low
Version:	4.6
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	RHBA-2008-0751	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2008-07-24 20:01:45 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:

Description David Tonhofer 2008-01-21 17:20:37 UTC

The "kill -0 $pid" (kill ZERO) option is apparently not to send a signal to 
some process but to test whether the process is alive.

A quick look at the source code of kill(1) shows that if 0 is given as signal
number, the kill(2) system call is performed with 0 (simple passthrough). The
man page of kill(2) says "If sig is 0, then no signal is sent, but error
checking is still performed."

--> So, a remark to that effect should be in the kill(1) manpage.

Note that the called "kill" will probably rarely be "/bin/kill" but instead the
bash-builtin "kill". The bash manpage has the same problem as described.

Comment 1 Karel Zak 2008-01-28 14:19:42 UTC

Fixed in util-linux-ng upstream code. Thanks for your report.

Comment 2 RHEL Program Management 2008-03-26 22:27:52 UTC

This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.

Comment 7 errata-xmlrpc 2008-07-24 20:01:45 UTC

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2008-0751.html