[libvirt] [PATCH] virprocess: make virProcessGetStartTime work on Mac OS X

[Doug Goldstein]

On Tue, Oct 15, 2013 at 12:05 PM, Ryota Ozaki <ozaki.ryota at gmail.com> wrote:
> This patch addresses the following warning output by libvirtd:
>   warning : virProcessGetStartTime:843 : Process start time of
>   pid XXXXX not available on this platform
>
> For Mac OS X, we can use similar instructions to FreeBSD
> to get the start time of a process. The difference between them
> is struct kinfo_proc; kinfo_proc.ki_start is the start time
> of a process for FreeBSD while kinfo_proc.kp_proc.p_starttime
> for Mac OS X.
>
> Note that this patch works for Lion and Mountain Lion, however,
> doesn't work for Snow Leopard for some reason;
> sysctlnametomib("kern.proc.pid", ...) fails on Snow Leopard with
> the following error:
>   error : virProcessGetStartTime:822 : Unable to get MIB of
>   kern.proc.pid: No such file or directory
>
> This is unexpected. man 3 sysctl of Snow Leopard says it
> should work...
>
> Anyway libvirtd is able to launch on Snow Leopard regardless of
> the error.
>
> Signed-off-by: Ryota Ozaki <ozaki.ryota at gmail.com>
> ---
>  src/util/virprocess.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index 9fc3207..5a0ed0d 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -32,7 +32,7 @@
>  #endif
>  #include <sched.h>
>
> -#ifdef __FreeBSD__
> +#if defined(__FreeBSD__) || defined(__APPLE__)
>  # include <sys/param.h>
>  # include <sys/sysctl.h>
>  # include <sys/user.h>
> @@ -809,7 +809,7 @@ cleanup:
>      VIR_FREE(buf);
>      return ret;
>  }
> -#elif defined(__FreeBSD__)
> +#elif defined(__FreeBSD__) || defined(__APPLE__)
>  int virProcessGetStartTime(pid_t pid,
>                             unsigned long long *timestamp)
>  {
> @@ -817,7 +817,12 @@ int virProcessGetStartTime(pid_t pid,
>      int mib[4];
>      size_t len = 4;
>
> -    sysctlnametomib("kern.proc.pid", mib, &len);
> +    /* FIXME: It doesn't work on Snow Leopard for some reason */
> +    if (sysctlnametomib("kern.proc.pid", mib, &len) < 0) {
> +        virReportSystemError(errno, "%s",
> +                             _("Unable to get MIB of kern.proc.pid"));
> +        return -1;
> +    }
>
>      len = sizeof(struct kinfo_proc);
>      mib[3] = pid;
> @@ -828,7 +833,11 @@ int virProcessGetStartTime(pid_t pid,
>          return -1;
>      }
>
> +# if defined(__FreeBSD__)
>      *timestamp = (unsigned long long)p.ki_start.tv_sec;
> +# else
> +    *timestamp = (unsigned long long)p.kp_proc.p_starttime.tv_sec;
> +# endif
>
>      return 0;
>
> --
> 1.8.4

I'm hesitant to ACK this because of the failure you mention on Snow
Leopard. The last time we merged something in that broke Snow Leopard
we got push back from the Homebrew guys so I'd rather let this bake a
bit more and figure out where the Snow Leopard issue is. I'm in the
process of installing Snow Leopard so I should have a chance to look
at it.

Additionally, we'll want to test this on the FreeBSDs (finishing up
installing a FreeBSD machine as well) since there is a behavior change
for FreeBSD in this patch.

-- 
Doug Goldstein