linux-kernel - Re: [PATCH] signalfd: retrieve multiple signals with one read() call

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Message-ID: <Pine.LNX.4.64.0705202112230.22011@alien.or.mcafeemobile.com>
Date:	Sun, 20 May 2007 21:14:38 -0700 (PDT)
From:	Davide Libenzi <davidel@...ilserver.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
cc:	Davi Arnaut <davi@...ent.com.br>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] signalfd: retrieve multiple signals with one read() call

On Sun, 20 May 2007, Andrew Morton wrote:

> If 'count' is not a multiple of sizeof(struct signalfd_siginfo)), the read()
> will return the next smallest multiple of `count'.
> 
> That is, unless `count' happens to be less than 1*sizeof(struct
> signalfd_siginfo)), in which case we return -EINVAL.
> 
> This seems inconsistent.

I think it fits the rule "buffer must be big enough for at least one sigingo".
We use the special return 0; as indicator that the process we were 
monitoring signals, detached the sighand.



> Also, I'm desperately hunting for the place where we zero out that local
> siginfo_t, and I ain't finding it.  Someone please convince me that we're
> not leaking bits of kernel memory out to userspace in that thing.

Hmm, __clear_user()?


- Davide


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