X-Recipient:	archive-cygwin AT delorie DOT com
X-Spam-Check-By:	sourceware.org
Date:	Sun, 28 Sep 2008 11:25:27 -0400
From:	Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
To:	cygwin AT cygwin DOT com
Subject:	Re: crash if fork(2) from another thread
Message-ID:	<20080928152527.GA2219@ednor.casa.cgf.cx>
Reply-To:	cygwin AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
References:	<003301c92110$336cee20$0200a8c0 AT whiterabc2znlh> <48DF3317 DOT 5060300 AT sh DOT cvut DOT cz>
MIME-Version:	1.0
In-Reply-To:	<48DF3317.5060300@sh.cvut.cz>
User-Agent:	Mutt/1.5.16 (2007-06-09)
Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id:	<cygwin.cygwin.com>
List-Unsubscribe:	<mailto:cygwin-unsubscribe-archive-cygwin=delorie DOT com AT cygwin DOT com>
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sourceware.org/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender:	cygwin-owner AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
Delivered-To:	mailing list cygwin AT cygwin DOT com

On Sun, Sep 28, 2008 at 09:32:39AM +0200, V??clav Haisman wrote:
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA256
>
>Hirokazu Yamamoto wrote, On 28.9.2008 4:16:
>> # I've post mail, but it didn't show up in
>> http://www.nabble.com/Cygwin-f12165.html.
>> # Maybe it was not good to attach a file. So try again...
>> 
>> I'm not familiar with pthread & fork, but I think following code should not
>> crash. Is this expected behavior?
>> 
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <pthread.h>
>> #include <assert.h>
>> 
>> void *thread_func(void* args)
>> {
>>     int ret;
>>     pid_t pid;
>>     pthread_t thread;
>> 
>>     puts("thread_func");
>> 
>>     pid = fork();
>> 
>>     assert(pid != (pid_t)-1);
>> 
>>     if (pid != 0) /* parent process */
>>     {
>>         int status;
>> 
>>         printf("parent process (child pid = %d)\n", pid);
>> 
>>         waitpid(pid, &status, 0);
>> 
>>         puts("parent process end");
>>     }
>>     else /* child process */
>>     {
>>         puts("child process"); /* crash here */
>I think this is not allowed in here.  You can only do async-signal-safe
>stuff in the child.  IO is AFAIK not in that category.  Basically, the
>only thing you can safely do in the child process is to call exec().

I don't see any reason why this shouldn't be allowed.  You should
be able to do anything you want in a child process.

cgf

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

- Raw text -