From: "Richard W.M. Jones" <rjones@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: corbet@lwn.net, akpm@linux-foundation.org, vbabka@suse.cz,
mhocko@suse.com, hughd@google.com, koct9i@gmail.com,
chenhanxiao@cn.fujitsu.com, n-horiguchi@ah.jp.nec.com,
ross.zwisler@linux.intel.com, john.stultz@linaro.org,
minchan@kernel.org, jmarchan@redhat.com, hannes@cmpxchg.org,
nathans@redhat.com, andriy.shevchenko@linux.intel.com,
keescook@chromium.org, gorcunov@openvz.org, joe@perches.com,
linux@rasmusvillemoes.dk, mingo@kernel.org, cmetcalf@ezchip.com,
iago@endocode.com, luto@kernel.org, linux-doc@vger.kernel.org,
gorcunov@gmail.com, fw@deneb.enyo.de, walters@verbum.org
Subject: [PATCH v2] procfs: expose umask in /proc/<PID>/status
Date: Thu, 14 Apr 2016 12:08:14 +0100 [thread overview]
Message-ID: <1460632095-434-1-git-send-email-rjones@redhat.com> (raw)
v1 -> v2:
- Change printf format to %#04o.
- Retest and update examples accordingly.
----------
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
Example usage:
$ grep Umask /proc/1/status
Umask: 0022
$ grep Umask /proc/2/status
Umask: 0022
$ grep Umask /proc/self/status
Umask: 0022
$ umask 002
$ grep Umask /proc/self/status
Umask: 0002
Rich.
next reply other threads:[~2016-04-14 11:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-14 11:08 Richard W.M. Jones [this message]
2016-04-14 11:08 ` Richard W.M. Jones
2016-04-14 12:34 ` Konstantin Khlebnikov
2016-04-14 12:41 ` Jerome Marchand
2016-04-15 13:13 ` Michal Hocko
2016-04-15 13:29 ` Richard W.M. Jones
2016-04-15 15:52 ` Theodore Ts'o
2016-04-15 16:43 ` Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1460632095-434-1-git-send-email-rjones@redhat.com \
--to=rjones@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=andriy.shevchenko@linux.intel.com \
--cc=chenhanxiao@cn.fujitsu.com \
--cc=cmetcalf@ezchip.com \
--cc=corbet@lwn.net \
--cc=fw@deneb.enyo.de \
--cc=gorcunov@gmail.com \
--cc=gorcunov@openvz.org \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=iago@endocode.com \
--cc=jmarchan@redhat.com \
--cc=joe@perches.com \
--cc=john.stultz@linaro.org \
--cc=keescook@chromium.org \
--cc=koct9i@gmail.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=luto@kernel.org \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=mingo@kernel.org \
--cc=n-horiguchi@ah.jp.nec.com \
--cc=nathans@redhat.com \
--cc=ross.zwisler@linux.intel.com \
--cc=vbabka@suse.cz \
--cc=walters@verbum.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®