[libvirt] [PATCH] Fix a potential race in pciInitDevice.

[Chris Lalancette]

If detecting the FLR flag of a pci device fails, then we
could run into the situation of trying to close a file
descriptor twice, once in pciInitDevice() and once in pciFreeDevice().
Fix that by removing the pciCloseConfig() in pciInitDevice() and
just letting pciFreeDevice() handle it.

Thanks to Chris Wright for pointing out this problem.

While we are at it, fix an error check.  While it would actually
work as-is (since success returns 0), it's still more clear to
check for < 0 (as the rest of the code does).

Signed-off-by: Chris Lalancette <clalance at redhat.com>
---
 src/qemu/qemu_driver.c |    2 +-
 src/util/pci.c         |    8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index b4c468a..9436e2a 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -8010,7 +8010,7 @@ static int qemudDomainAttachHostPciDevice(struct qemud_driver *driver,
         return -1;
     }
 
-    if (qemuPrepareHostdevPCIDevices(driver, &hostdev, 1))
+    if (qemuPrepareHostdevPCIDevices(driver, &hostdev, 1) < 0)
         return -1;
 
     if (qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE) {
diff --git a/src/util/pci.c b/src/util/pci.c
index 14ef058..26d55b8 100644
--- a/src/util/pci.c
+++ b/src/util/pci.c
@@ -189,8 +189,10 @@ pciCloseConfig(pciDevice *dev)
     if (!dev)
         return;
 
-    if (dev->fd >= 0)
+    if (dev->fd >= 0) {
         close(dev->fd);
+        dev->fd = -1;
+    }
 }
 
 static int
@@ -673,10 +675,8 @@ pciInitDevice(pciDevice *dev)
     dev->pcie_cap_pos   = pciFindCapabilityOffset(dev, PCI_CAP_ID_EXP);
     dev->pci_pm_cap_pos = pciFindCapabilityOffset(dev, PCI_CAP_ID_PM);
     flr = pciDetectFunctionLevelReset(dev);
-    if (flr < 0) {
-        pciCloseConfig(dev);
+    if (flr < 0)
         return flr;
-    }
     dev->has_flr        = flr;
     dev->has_pm_reset   = pciDetectPowerManagementReset(dev);
     dev->initted        = 1;
-- 
1.7.1.1