Re: [libvirt] [PATCH] qemu: don't fill in nicindexes for session mode libvirtd

10 Mar 2015

On Tue, Mar 10, 2015 at 02:32:04AM -0400, Laine Stump wrote:
...
Commit 4bbe1029f fixed a problem in commit f7afeddc by moving the call
to virNetDevGetIndex() to a location common to all interface types (so
that the niceindex array would be filled in for macvtap as well as tap
interfaces), but the location was *too* common, as the original call
to virNetDevGetIndex() had been in a section qualified by "if
(cfg->privileged)". The result was that the "fixed" libvirtd would try
to call virNetDevGetIndex() even for session mode libvirtd, and end up
failing with the log message:
Unable to open control socket: Operation not permitted
To remedy that, this patch qualifies the call to virNetDevGetIndex()
in its new location with cfg->privileged.
This resolves https://bugzilla.redhat.com/show_bug.cgi?id=1198244
---
If someone (Rich?) needs this pushed before I am awake, please feel
free to push it. (also push to the 1.2.13-maint branch if you do)
src/qemu/qemu_command.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 1510797..3d1483e 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -7861,6 +7861,7 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd,
     char **tapfdName = NULL;
     char **vhostfdName = NULL;
     int actualType = virDomainNetGetActualType(net);
+    virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     virNetDevBandwidthPtr actualBandwidth;
     size_t i;
@@ -7936,7 +7937,7 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd,
         /* network and bridge use a tap device, and direct uses a
          * macvtap device
          */
-        if (nicindexes && nnicindexes && net->ifname) {
+        if (cfg->privileged && nicindexes && nnicindexes && net->ifname) {
             if (virNetDevGetIndex(net->ifname, &nicindex) < 0 ||
                 VIR_APPEND_ELEMENT(*nicindexes, *nnicindexes, nicindex) < 0)
                 goto cleanup;
Just tested with this patch locally, using Rich's reproducer. Fixes the
issue.

Before applying this patch, tested with version
libvirt-daemon-kvm-1.2.13-1.fc23.x86_64:

  $ whoami
  kashyapc

  $ guestfish -a /dev/null --network run
  libguestfs: error: could not create appliance through libvirt.
  . . .
  Original error from libvirt: Unable to open control socket: Operation not permitted [code=38 domain=0]


After applying this patch (applied on current git):

    $ git describe
    v1.2.13-100-gb7d027b

    $ guestfish -a /dev/null --network run
    $ echo $?
    0


So, FWIW:

    Tested-By: Kashyap Chamarthy <kchamart@redhat.com>

-- 
/kashyap

    