[libvirt] [PATCH v2] libxl: load on FreeBSD

[Roman Bogorodskiy]

  Jim Fehlig wrote:

> On 05/27/2015 09:06 AM, Martin Kletzander wrote:
> > On Sun, May 24, 2015 at 06:45:02PM +0300, Roman Bogorodskiy wrote:
> >> The libxl tries to check if it's running in dom0 by parsing
> >> /proc/xen/capabilities and if that fails it doesn't load.
> >>
> >> There's no procfs interface in Xen on FreeBSD, so this check always
> >> fails.
> >>
> >> In addition to checking procfs, check if /dev/xen/xenstored, that's enough to
> >> check if we're running in dom0 in FreeBSD case.
> >> ---
> >> src/libxl/libxl_driver.c | 42 ++++++++++++++++++++++--------------------
> >> 1 file changed, 22 insertions(+), 20 deletions(-)
> >>
> >> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
> >> index 12be816..fddafa1 100644
> >> --- a/src/libxl/libxl_driver.c
> >> +++ b/src/libxl/libxl_driver.c
> >> @@ -74,6 +74,7 @@ VIR_LOG_INIT("libxl.libxl_driver");
> >> #define LIBXL_CONFIG_FORMAT_SEXPR "xen-sxpr"
> >>
> >> #define HYPERVISOR_CAPABILITIES "/proc/xen/capabilities"
> >> +#define HYPERVISOR_XENSTORED "/dev/xen/xenstored"
> >>
> >> /* Number of Xen scheduler parameters */
> >> #define XEN_SCHED_CREDIT_NPARAM   2
> >> @@ -427,8 +428,6 @@ static bool
> >> libxlDriverShouldLoad(bool privileged)
> >> {
> >>     bool ret = false;
> >> -    int status;
> >> -    char *output = NULL;
> >>
> >>     /* Don't load if non-root */
> >>     if (!privileged) {
> >> @@ -436,24 +435,27 @@ libxlDriverShouldLoad(bool privileged)
> >>         return ret;
> >>     }
> >>
> >> -    if (!virFileExists(HYPERVISOR_CAPABILITIES)) {
> >> -        VIR_INFO("Disabling driver as " HYPERVISOR_CAPABILITIES
> >> -                 " does not exist");
> >> -        return ret;
> >> -    }
> >> -    /*
> >> -     * Don't load if not running on a Xen control domain (dom0). It is not
> >> -     * sufficient to check for the file to exist as any guest can mount
> >> -     * xenfs to /proc/xen.
> >> -     */
> >> -    status = virFileReadAll(HYPERVISOR_CAPABILITIES, 10, &output);
> >> -    if (status >= 0)
> >> -        status = strncmp(output, "control_d", 9);
> >> -    VIR_FREE(output);
> >> -    if (status) {
> >> -        VIR_INFO("No Xen capabilities detected, probably not running "
> >> -                 "in a Xen Dom0.  Disabling libxenlight driver");
> >> -
> >> +    if (virFileExists(HYPERVISOR_CAPABILITIES)) {
> >> +        int status;
> >> +        char *output = NULL;
> >> +        /*
> >> +         * Don't load if not running on a Xen control domain (dom0). It is not
> >> +         * sufficient to check for the file to exist as any guest can mount
> >> +         * xenfs to /proc/xen.
> >> +         */
> >> +        status = virFileReadAll(HYPERVISOR_CAPABILITIES, 10, &output);
> >> +        if (status >= 0)
> >> +            status = strncmp(output, "control_d", 9);
> >> +        VIR_FREE(output);
> >> +        if (status) {
> >> +            VIR_INFO("No Xen capabilities detected, probably not running "
> >> +                     "in a Xen Dom0.  Disabling libxenlight driver");
> >> +
> >> +            return ret;
> >> +        }
> >> +    } else if (!virFileExists(HYPERVISOR_XENSTORED)) {
> >> +        VIR_INFO("Disabling driver as neither " HYPERVISOR_CAPABILITIES
> >> +                 " nor " HYPERVISOR_CAPABILITIES " exist");
> >
> > s/HYPERVISOR_CAPABILITIES/HYPERVISOR_XENSTORED/
> >
> > ACK with that changed.
> 
> For the record, I tested this on Linux.  Looks good with Martin's comment addressed.
> 
> Regards,
> Jim

Thanks for giving it a test!

Is this safe to push during the freeze?

Roman Bogorodskiy