Re: [Qemu-trivial] [PATCH] keep the PID file locked for the lifetime of the process

[Stefan Hajnoczi]

On Thu, Jan 26, 2012 at 10:36:41PM +0100, Laszlo Ersek wrote:
> The lockf() call in qemu_create_pidfile() aims at ensuring mutual
> exclusion. We shouldn't close the pidfile on success, because that drops
> the lock as well [1]:
> 
>     "File locks shall be released on first close by the locking process
>     of any file descriptor for the file."
> 
> Coverity may complain again about the leaked file descriptor; let's
> worry about that later.
> 
> [1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/lockf.html
> 
> Signed-off-by: Laszlo Ersek <address@hidden>
> ---

Isn't the normal way to do pidfiles O_CREAT | O_EXCL?  It may not work
on all NFS versions but putting the pidfile on NFS doesn't really make
sense.

Then we can drop the lockf(3) completely.

Stefan