From mboxrd@z Thu Jan  1 00:00:00 1970
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH] libxl: Be more careful with error handling
 in libxl__dm_runas_helper()
Date: Tue, 1 Dec 2015 10:32:29 -0500
Message-ID: <565DBD8D.2040204@oracle.com>
References: <1448488569-3003-1-git-send-email-boris.ostrovsky@oracle.com>
	<22103.17713.650054.585156@mariner.uk.xensource.com>
	<1448617231.13576.56.camel@citrix.com> <565C9440.1030408@oracle.com>
	<1448980733.15768.137.camel@citrix.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <1448980733.15768.137.camel@citrix.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Ian Campbell <ian.campbell@citrix.com>, Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: xen-devel@lists.xen.org, wei.liu2@citrix.com, stefano.stabellini@eu.citrix.com
List-Id: xen-devel@lists.xenproject.org

On 12/01/2015 09:38 AM, Ian Campbell wrote:
> On Mon, 2015-11-30 at 13:24 -0500, Boris Ostrovsky wrote:
>>       root@orochi-c> cat /etc/redhat-release
>>       Fedora release 20 (Heisenbug)
>>       root@orochi-c> ./a.out foobar
>>       s = 2 errno = 2 result = (nil)
>>       getpwnam_r: No such file or directory
>>       root@orochi-c>
>>
>> which does look like a bug in F20 since the code above is taken from man
>> pages' EXAMPLE and doesn't look like it works as intended (which was to
>> produce "Not found" string)
> https://bugzilla.redhat.com/show_bug.cgi?id=988068 seems related (although
> is blaming "sssd" rather than glibc it seems).

This too:

https://sourceware.org/bugzilla/show_bug.cgi?id=17922

They claim that glibc v2.20 fails (i.e. returns non-zero/ENOENT) but in 
my case on fedora 21 with 2.20-8 I get 0. My "failing" fedora 20 uses 2.18.

I don't know whether it's really a bug in glibc since Linux man pages do 
allow ENOENT (and some other codes) to indicate absence of entry. (But 
then if this is not a bug in glibc then there is a bug in man pages' 
example code).

In any case, I think we need to account for this in libxl.

-boris