[libvirt] [PATCH] Honor blacklist for modprobe command
Daniel P. Berrange
berrange at redhat.com
Wed Jan 29 10:40:39 UTC 2014
On Tue, Jan 28, 2014 at 07:00:16PM -0500, John Ferlan wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1045124
>
> When loading modules, libvirt does not honor the modprobe blacklist.
> By adding a "-b" to the modprobe command libvirt will fail to load a
> module if it's on the blacklist
>
> Check if the failure to load a driver was due to it being on the blacklist
> using the output of a "modprobe -c" searching for "blacklist <driver_Name>"
> where driver_Name is possibly a modified string of the input driver changing
> all '-' into '_' since that's what modprobe does.
>
> Signed-off-by: John Ferlan <jferlan at redhat.com>
> ---
> src/util/virpci.c | 48 ++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 42 insertions(+), 6 deletions(-)
>
> diff --git a/src/util/virpci.c b/src/util/virpci.c
> index e2d222e..18b85f2 100644
> --- a/src/util/virpci.c
> +++ b/src/util/virpci.c
> @@ -979,6 +979,10 @@ virPCIProbeStubDriver(const char *driver)
> {
> char *drvpath = NULL;
> bool probed = false;
> + size_t i;
> + char *drvblklst = NULL;
> + char *outbuf = NULL;
> + virCommandPtr cmd = NULL;
>
> recheck:
> if (virPCIDriverDir(&drvpath, driver) == 0 && virFileExists(drvpath)) {
> @@ -990,18 +994,49 @@ recheck:
> VIR_FREE(drvpath);
>
> if (!probed) {
> - const char *const probecmd[] = { MODPROBE, driver, NULL };
> + cmd = virCommandNewArgList(MODPROBE, "-b", driver, NULL);
> probed = true;
> - if (virRun(probecmd, NULL) < 0) {
> + if (virCommandRun(cmd, NULL) < 0) {
> char ebuf[1024];
> VIR_WARN("failed to load driver %s: %s", driver,
> virStrerror(errno, ebuf, sizeof(ebuf)));
> - return -1;
> + goto cleanup;
> }
> + virCommandFree(cmd);
> + cmd = NULL;
>
> goto recheck;
> }
>
> + /* All error path code - purpose is to determine whether the failure
> + * occurs because device is on blacklist in order to add an error
> + * message to help detect why load failed
> + */
> + if (virAsprintfQuiet(&drvblklst, "blacklist %s", driver) < 0)
> + goto cleanup;
> +
> + /* Although driver may have dash, 'modprobe -c' adjusts to use underscore */
> + for (i = 0; i < drvblklst[i]; i++)
> + if (drvblklst[i] == '-')
> + drvblklst[i] = '_';
> +
> + cmd = virCommandNewArgList(MODPROBE, "-c", NULL);
> + virCommandSetOutputBuffer(cmd, &outbuf);
> + if (virCommandRun(cmd, NULL) < 0)
> + goto cleanup;
> +
> + /* Find driver on blacklist? */
> + if (strstr(outbuf, drvblklst)) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Failed to load PCI stub module %s: "
> + "administratively prohibited"),
> + driver);
> + }
> +
> +cleanup:
> + virCommandFree(cmd);
> + VIR_FREE(drvblklst);
> + VIR_FREE(outbuf);
> return -1;
> }
This is getting complex enough that I think we ought introduce
a src/util/virkmod.{c,h} and have some helper APIs in there
for loading and unload modules. eg virKModLoad, virKModUnload
etc
Regards,
Daniel
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