lkml.org 
[lkml]   [2016]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] procfs: expose umask in /proc/<PID>/status (formerly umask2, formerly getumask)
On Thu, Apr 14, 2016 at 10:34:48AM +0100, Richard W.M. Jones wrote:
> It's not possible to read the process umask without also modifying it,
> which is what umask(2) does. A library cannot read umask safely,
> especially if the main program might be multithreaded.
>
> Add a new status line ("Umask") in /proc/<PID>/status. It contains
> the file mode creation mask (umask) in octal. It is only shown for
> tasks which have task->fs.
>
> For the library this allows me to read the umask from
> /proc/self/status.
>
> This patch is adapted from one originally written by Pierre Carrier:
> https://lkml.org/lkml/2012/5/4/451

Sorry, I meant to add an example of what this looks like:

$ grep Umask /proc/1/status
Umask: 022
$ grep Umask /proc/2/status
Umask: 022
$ grep Umask /proc/self/status
Umask: 022
$ umask 002
$ grep Umask /proc/self/status
Umask: 02

Rich.

--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines. Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top

\
 
 \ /
  Last update: 2016-04-14 11:41    [W:0.055 / U:0.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site