[libvirt] [PATCH] Check if systemd is the init before creating machines

[Daniel P. Berrange]

On Thu, Feb 27, 2014 at 09:29:24PM +0100, Ján Tomko wrote:
> If systemd is installed, but not the init system,
> systemd-machined fails with an unhelpful error message:
> Launch helper exited with unknown return code 1
> 
> Fall back to manual cgroup creation if systemd is installed,
> but it's not PID 1.
> 
> [1] https://bugs.freedesktop.org/show_bug.cgi?id=69962
> ---
> 
> (Yes, Gentoo.)
> 
>  src/util/virsystemd.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/src/util/virsystemd.c b/src/util/virsystemd.c
> index 8adf209..0404a63 100644
> --- a/src/util/virsystemd.c
> +++ b/src/util/virsystemd.c
> @@ -30,6 +30,7 @@
>  #include "virstring.h"
>  #include "viralloc.h"
>  #include "virutil.h"
> +#include "virfile.h"
>  #include "virlog.h"
>  #include "virerror.h"
>  
> @@ -142,6 +143,28 @@ cleanup:
>      return machinename;
>  }
>  
> +/*
> + * Returns 0 if systemd is the init, -2 if not
> + * -1 on fatal error
> + */
> +static int
> +virSystemdIsInit(void)
> +{
> +    char *buf = NULL;
> +    int ret = -2;
> +
> +    if (virFileReadAll("/proc/1/comm", sizeof("systemd\n "), &buf) < 0)
> +        return -1;
> +
> +    if (STREQ(buf, "systemd\n"))
> +        ret = 0;
> +    else
> +        VIR_DEBUG("systemd is not the init");
> +
> +    VIR_FREE(buf);
> +    return ret;
> +}
> +
>  /**
>   * virSystemdCreateMachine:
>   * @name: driver unique name of the machine
> @@ -173,6 +196,9 @@ int virSystemdCreateMachine(const char *name,
>      if (ret < 0)
>          return ret;
>  
> +    if ((ret = virSystemdIsInit()) < 0)
> +        return ret;
> +

We already do a call

    ret = virDBusIsServiceEnabled("org.freedesktop.machine1");

I'd suggest that we perhaps also call

    ret = virDBusIsServiceEnabled("org.freedesktop.systemd1");

instead of looking in /proc/1/comm


Regards,
Daniel
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