Re: [Qemu-devel] [PATCH v2 2/8] qemu-ga: move channel/transport functionalit

[Michael Roth <mdroth@linux.vnet.ibm.com>]

On 02/02/2012 10:25 PM, MATSUDA, Daiki wrote:
> Hi, Michael!
> Thank you for your working.
>
> And I have a question the process id written in pid file.
> If qemu-ga is ran as daemon, the parent process id not child is written
> in pid file. So, id gotten by 'ps' command is different. Is it correct
> work? Many other daemon writes child process id.
>
> Regards
> MATSUDA Daiki
>

Hi Matsuda,

Thank you for testing!

In the become_daemon() function, the parent exits immediately after the 
fork(), so only the child has the opportunity to write to the pid file. 
It calls getpid() to get the pid to write, which should be it's own 
lwpid. So I'm not seeing where there's an opportunity for the parent pid 
to be written.

Can you confirm? It seems to behave as expected for me:

[root@vm ~]# /home/mdroth/w/qemu-build/qemu-ga -d
** (process:7441): DEBUG: starting daemon
[root@vm ~]# ps aux | grep qemu-ga
root      7442  0.0  0.0  13792   348 ?        Ss   10:56   0:00 
/home/mdroth/w/qemu-build/qemu-ga -d
root      7471  0.0  0.1 109108   816 pts/2    R+   11:00   0:00 grep 
--color=auto qemu-ga
[root@vm ~]# cat /var/run/qemu-ga.pid
7442