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Re: [PATCH v2 6/7] xfsdump: convert to the POSIX signal API

To: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Subject: Re: [PATCH v2 6/7] xfsdump: convert to the POSIX signal API
From: Bill Kendall <wkendall@xxxxxxx>
Date: Mon, 15 Aug 2011 08:10:48 -0500
Cc: aelder@xxxxxxx, xfs@xxxxxxxxxxx
In-reply-to: <20110812204554.GA30615@xxxxxxxxxxxxx>
References: <1312497011-24840-1-git-send-email-wkendall@xxxxxxx> <1312497011-24840-7-git-send-email-wkendall@xxxxxxx> <1313012883.2865.139.camel@doink> <4E457BEE.7060704@xxxxxxx> <20110812204554.GA30615@xxxxxxxxxxxxx>
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On 08/12/2011 03:45 PM, Christoph Hellwig wrote:
On Fri, Aug 12, 2011 at 02:15:58PM -0500, Bill Kendall wrote:
Is there any requirement that the fields
other than sa_flags and sa_handler should
be zeroed before use?

The sa_sigaction field will only be used if sa_flags
has SA_SIGINFO set, and the sa_restored field is obsolete
and not specified by POSIX. Better to explicitly initialize
everything though, so I'll change that.

sigaction actuall is a rare case where this is harmful.  To quote
the manpage:

        On some architectures a union is involved:  do not assign to both
        sa_handler and sa_sigaction.

Thanks, I do remember reading this now. I'll leave the code as is,
which sets sa_handler instead of sa_sigaction, and does not touch
the obsolete (possibly undefined) sa_restorer. The rest of the
fields are initialized.

Bill

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