[libvirt] [PATCH] qemu: pass "-1" as uid/gid for unprivileged qemu

[Guido Günther]

so we don't try to change uid/git to 0 when probing capabilities.
---

On Fri, Feb 15, 2013 at 11:20:17PM -0600, Doug Goldstein wrote:
> The following error bisect's down to this commit when running out of
> my local checkout for testing.
> 
> 2013-02-16 05:16:55.102+0000: 29992: error : virCommandWait:2270 :
> internal error Child process (LC_ALL=C
> LD_LIBRARY_PATH=/home/cardoe/work/libvirt/src/.libs
> PATH=/usr/local/bin:/usr/bin:/bin:/opt/bin:/usr/x86_64-pc-linux-gnu/gcc-bin/4.6.3:/usr/games/bin
> HOME=/home/cardoe USER=cardoe LOGNAME=cardoe /usr/bin/qemu-kvm -help)
> unexpected exit status 1: libvir:  error : internal error cannot apply
> process capabilities -1

This is due to:

debug : virExec:641 : Setting child uid:gid to 0:0 with caps 0

We're trying to change capabilities even on qemu:///session. This
unbreaks the libvirt-tck jenkins test suite as well.

 src/qemu/qemu_driver.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 23499ef..dc35b91 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -556,6 +556,8 @@ qemuStartup(bool privileged,
     char *membase = NULL;
     char *mempath = NULL;
     virQEMUDriverConfigPtr cfg;
+    uid_t run_uid = -1;
+    gid_t run_gid = -1;
 
     if (VIR_ALLOC(qemu_driver) < 0)
         return -1;
@@ -707,11 +709,13 @@ qemuStartup(bool privileged,
                                  cfg->snapshotDir, cfg->user, cfg->group);
             goto error;
         }
+        run_uid = cfg->user;
+        run_gid = cfg->group;
     }
 
     qemu_driver->qemuCapsCache = virQEMUCapsCacheNew(cfg->libDir,
-                                                     cfg->user,
-                                                     cfg->group);
+                                                     run_uid,
+                                                     run_gid);
     if (!qemu_driver->qemuCapsCache)
         goto error;
 
-- 
1.7.10.4