Re: [Xen-devel] [PATCH 1/3] Make xenstored manage its own pidfile

[Muli Ben-Yehuda <mulix@xxxxxxxxx>]

On Thu, Aug 04, 2005 at 11:03:11AM -0500, Anthony Liguori wrote:

> The following patch makes xenstored manage its own pidfile which makes 
> it impossible for it to be started multiple times.
> 
> Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx
> 
> Regards,
> 
> Anthony Liguori

> diff -r 1d240086de52 tools/xenstore/utils.c
> --- a/tools/xenstore/utils.c  Thu Aug  4 15:02:09 2005
> +++ b/tools/xenstore/utils.c  Thu Aug  4 10:54:13 2005
> @@ -84,6 +84,9 @@
>  void daemonize(void)
>  {
>       pid_t pid;
> +     int fd;
> +     size_t len;
> +     char buf[100];
>  
>       /* Separate from our parent via fork, so init inherits us. */
>       if ((pid = fork()) < 0)
> @@ -101,6 +104,18 @@
>       chdir("/");
>       /* Discard our parent's old-fashioned umask prejudices. */
>       umask(0);
> +
> +     fd = open("/var/run/xenstored.pid", O_RDWR | O_CREAT);
> +     if (fd == -1) {
> +             exit(1);

How about exit(errno), with or without a descriptive message?

> +     }
> +
> +     if (lockf(fd, F_TLOCK, 0) == -1) {
> +             exit(1);

Likewise?

> +
> +     len = sprintf(buf, "%d\n", getpid());
> +     write(fd, buf, len);

Check returen value from write?

Cheers,
Muli
-- 
Muli Ben-Yehuda
http://www.mulix.org | http://mulix.livejournal.com/


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