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From: David Newall <glibc@davidnewall.com>
To: Rich Felker <dalias@libc.org>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
	libc-alpha@sourceware.org
Subject: Re: [PATCH 2/3] posix: Use posix_spawn on popen
Date: Tue, 18 Sep 2018 01:31:00 -0000	[thread overview]
Message-ID: <87797b78-a951-f80b-553f-b9e6d208c073@davidnewall.com> (raw)
In-Reply-To: <20180917145025.GJ17995@brightrain.aerifal.cx>

On 18/09/18 00:20, Rich Felker wrote:
> The historical contract of vfork is that you can basically do nothing
> after it returns in the child except for exec or _exit
Yes, that is true.  My  understanding is that vfork was intended only as 
a fast way of doing fork/exec sequence.

> One thing to note is that vfork is completely unsafe to use as
> documented if any signal handlers are installed, unless you block all
> signals before calling vfork, in which case the exec'd process will
> inherit a fully-blocked signal mask which is probably not what you
> want. Otherwise signal handlers may wrongly run in the child that's
> sharing memory with the parent.

You're saying that kernel will deliver a signal to child pid when it was 
parent pid that was signalled.  Can that really happen?

  parent reply	other threads:[~2018-09-18  1:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-15 15:18 [PATCH 1/3] posix: Add internal symbols for posix_spawn interface Adhemerval Zanella
2018-09-15 15:16 ` [PATCH 2/3] posix: Use posix_spawn on popen Adhemerval Zanella
2018-09-16  5:13   ` David Newall
2018-09-17 14:50     ` Rich Felker
2018-09-17 17:32       ` Adhemerval Zanella
2018-09-18  1:31       ` David Newall [this message]
2018-09-18  3:12         ` Rich Felker
2018-09-18 18:01     ` Zack Weinberg
2018-09-19  5:18       ` Rich Felker
2018-09-19 15:53         ` Adhemerval Zanella
2018-10-17 17:20   ` Adhemerval Zanella
2018-10-19 22:08     ` Adhemerval Zanella
2018-09-15 15:18 ` [PATCH 3/3] posix: Use posix_spawn on system Adhemerval Zanella
2018-10-17 20:13   ` Adhemerval Zanella
2018-09-17 12:12 ` [PATCH 1/3] posix: Add internal symbols for posix_spawn interface Florian Weimer
2018-09-17 19:10   ` Adhemerval Zanella
2018-09-21 13:09     ` Florian Weimer
2018-10-17 17:11 ` Adhemerval Zanella

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