Date: Thu, 2 Apr 2009 18:06:17 +0200
From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: execve issues, and execve with cygrunsrv
Message-ID: <20090402160617.GC12738@calimero.vinschen.de>
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References: <49D0B0CD.6050009@pocock.com.au> <20090331112427.GC12738@calimero.vinschen.de> <49D4D802.8040005@pocock.com.au>
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On Apr  2 16:21, Daniel Pocock wrote:
> Corinna Vinschen wrote:
>> Did you try?
>>   
> I have now had a chance to try it under cygrunsrv from Cygwin 1.5.25 and 1.7
>
> Under 1.5.25, it doesn't work because of the sockets issue
>
> Under 1.7, a new issue is revealed: execve doesn't maintain the same  
> process ID, so cygrunsrv thinks the service has actually stopped, and  
> the cygrunsrv process exits.  This is obviously quite bad.

Huh?  The *Windows* PID is not the same after an exec, but the
Cygwin PID is maintained after an exec.  Try this:


    #include <stdio.h>
    #include <unistd.h>
    #include <sys/types.h>
    #include <sys/wait.h>
    #include <windows.h>

    int main(int argc, char **argv)
    {
      int status;

      if (argc > 1)
	{
	  printf ("Execed Child: Cygwin: %d Windows: %lu\n",
		  getpid (), GetCurrentProcessId ());
	  return 0;
	}
      printf ("Parent: Cygwin: %d Windows: %lu\n",
	      getpid (), GetCurrentProcessId ());
      switch (fork ())
	{
	case 0:
	  printf ("Forked Child: Cygwin: %d Windows: %lu\n",
		  getpid (), GetCurrentProcessId ());
	  execl ("./x", "x", "child", NULL);
	  break;
	default:
	  break;
	}
      wait (&status);
      return 0;
    }


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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