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From: Colin Walters <walters-gPq2gbYjIk8dnm+yROfE0A@public.gmane.org>
To: "Richard W.M. Jones"
	<rjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
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Subject: Re: [PATCH v2 0/2] vfs: Define new syscall getumask.
Date: Wed, 13 Apr 2016 11:41:45 -0400	[thread overview]
Message-ID: <1460562105.353100.577697153.013DF466@webmail.messagingengine.com> (raw)
In-Reply-To: <1460552272-15985-1-git-send-email-rjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

On Wed, Apr 13, 2016, at 08:57 AM, 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.

I assume you just want to do this from a shared library so you can
determine whether or not you need to call fchown() after making files
and the like?  If that's the case it'd be good to note it in the commit
message.

BTW...it might be a good idea to add a flags argument:
https://lwn.net/Articles/585415/

Did you consider calling this `umask2`, having the initial version only support
retrieving it via a UMASK_GET flag, and lay the groundwork to support
setting a threadsafe umask with a UMASK_SET_THREAD flag?

  parent reply	other threads:[~2016-04-13 15:41 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-13 12:57 [PATCH v2 0/2] vfs: Define new syscall getumask Richard W.M. Jones
2016-04-13 12:57 ` [PATCH v2 1/2] " Richard W.M. Jones
     [not found]   ` <1460552272-15985-2-git-send-email-rjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-04-13 13:20     ` Cyrill Gorcunov
2016-04-13 13:57       ` Richard W.M. Jones
     [not found]         ` <20160413135708.GG11600-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-04-13 14:02           ` Christoph Hellwig
2016-04-13 15:27           ` Mathieu Desnoyers
     [not found] ` <1460552272-15985-1-git-send-email-rjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-04-13 12:57   ` [PATCH v2 2/2] x86: Wire up new getumask system call on x86 Richard W.M. Jones
2016-04-13 13:59   ` [PATCH v2 0/2] vfs: Define new syscall getumask Greg KH
2016-04-14  3:47     ` Steven Rostedt
2016-04-14 19:26       ` Greg KH
2016-04-13 15:39   ` Mathieu Desnoyers
     [not found]     ` <2143735451.55767.1460561962122.JavaMail.zimbra-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>
2016-04-13 21:01       ` Mathieu Desnoyers
     [not found]         ` <1736004700.56566.1460581285951.JavaMail.zimbra-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>
2016-04-14  2:13           ` Theodore Ts'o
     [not found]             ` <20160414021348.GB16656-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2016-04-18  0:38               ` H. Peter Anvin
     [not found]                 ` <57142C80.6070005-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2016-04-18  1:09                   ` Greg KH
     [not found]                     ` <20160418010925.GA7800-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2016-04-18  2:02                       ` H. Peter Anvin
2016-04-18  2:12                       ` Josh Triplett
2016-04-18  2:15                         ` H. Peter Anvin
2016-04-18  2:37                           ` Josh Triplett
2016-04-18  3:00                             ` H. Peter Anvin
     [not found]                               ` <57144DE6.9050409-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2016-04-18 11:39                                 ` Theodore Ts'o
2016-04-14 17:56           ` Andy Lutomirski
2016-04-13 15:41   ` Colin Walters [this message]
     [not found]     ` <1460562105.353100.577697153.013DF466-2RFepEojUI2N1INw9kWLP6GC3tUn3ZHUQQ4Iyu8u01E@public.gmane.org>
2016-04-13 16:03       ` Richard W.M. Jones
2016-04-18  1:42       ` H. Peter Anvin
     [not found]         ` <57143B74.3070302-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2016-04-18  1:57           ` Josh Triplett
2016-04-18  9:14             ` Richard W.M. Jones
2016-04-18 10:04               ` H. Peter Anvin

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