From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wei Liu <wei.liu2@citrix.com>
Subject: Re: [PATCH v2] tools/xenconsoled: Increase file
	descriptor limit
Date: Tue, 17 Feb 2015 16:48:11 +0000
Message-ID: <20150217164811.GI2159@zion.uk.xensource.com>
References: <1424190084-9922-1-git-send-email-andrew.cooper3@citrix.com>
	<20150217162831.GH2159@zion.uk.xensource.com>
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To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>, Wei Liu <wei.liu2@citrix.com>, Ian Campbell <Ian.Campbell@citrix.com>, Xen-devel <xen-devel@lists.xen.org>
List-Id: xen-devel@lists.xenproject.org

On Tue, Feb 17, 2015 at 04:37:08PM +0000, Andrew Cooper wrote:
[...]
> >> +
> > This function looks Linux centric (/proc and CAP_SYSRESOURCE). Please be
> > considerate to other Unices. :-)
> >
> > Also you might want to log failures along the line.
> >
> > Wei.
> 
> setrlimit() is posix.  From the manpage:
> 
> CONFORMING TO
>        getrlimit(), setrlimit(): SVr4, 4.3BSD, POSIX.1-2001.
> 

True.

> "/proc/sys/fs/nr_open" is likely Linux only, but not fatal, and doesn't
> prevent an arbitrary grab for 4096 descriptors.
> 

Please use

  #if defined(__linux__)

for Linux specific code.

> 
> I am not sure what an admin could usefully do with a logged failure
> message here.  Xenconsoled will most likely not function in an
> environment where it is not sufficiently privileged to make this limit
> adjustment (use of privcmd and /dev/ptmx).
> 

Does xenconsoled requires CAP_SYS_RESOURCE to make use of privcmd and
/dev/ptmx? If not, there is a case that your setrlimit fails
while other parts can still be functional, right?

Wei.

> ~Andrew