[libvirt] [PATCH] virUSBDeviceNew: Construct vroot path properly

[Michal Privoznik]

When starting an LXC container, the /dev entries are created
under temp root (/var/run/libvirt/lxc/$name.dev), relabelled and
then the root is pivoted. However, when it comes to USB devices
which keep path to the device in the structure we need a way to
override the default /dev/usb/... path because we want to work
with the one under temp root. That's what @vroot argument is for
in virUSBDeviceNew. However, what is being passed there is:

  vroot = /var/run/libvirt/lxc/lxc_0.dev/bus/usb

Therefore, constructed path is wrong:

  dev->path = //var/run/libvirt/lxc/lxc_0.dev/bus/usb//dev/bus/usb/002/002

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/util/virusb.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/util/virusb.c b/src/util/virusb.c
index 6359235ff..f06639eec 100644
--- a/src/util/virusb.c
+++ b/src/util/virusb.c
@@ -343,9 +343,13 @@ virUSBDeviceNew(unsigned int bus,
         virUSBDeviceFree(dev);
         return NULL;
     }
-    if (virAsprintf(&dev->path, "%s" USB_DEVFS "%03d/%03d",
-                    vroot ? vroot : "",
-                    dev->bus, dev->dev) < 0) {
+
+    if ((vroot &&
+         virAsprintf(&dev->path, "%s/%03d/%03d",
+                     vroot, dev->bus, dev->dev) < 0) ||
+        (!vroot &&
+         virAsprintf(&dev->path, USB_DEVFS "%03d/%03d",
+                     dev->bus, dev->dev) < 0)) {
         virUSBDeviceFree(dev);
         return NULL;
     }
-- 
2.13.6