[libvirt] [PATCH 11/12] vz: acquire a pidfile in the driver root directory
When we allow multiple instances of the driver for the same user
account, using a separate root directory, we need to ensure mutual
exclusion. Use a pidfile to guarantee this.
In privileged libvirtd this ends up locking
/var/run/libvirt/vz/driver.pid
In unprivileged libvirtd this ends up locking
/run/user/$UID/libvirt/vz/run/driver.pid
NB, the latter can vary depending on $XDG_RUNTIME_DIR
Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com>
---
src/vz/vz_driver.c | 40 +++++++++++++++++++++++++++++++++++-----
1 file changed, 35 insertions(+), 5 deletions(-)
diff --git a/src/vz/vz_driver.c b/src/vz/vz_driver.c
index 2286f9a04f..c5152c309c 100644
--- a/src/vz/vz_driver.c
+++ b/src/vz/vz_driver.c
@@ -41,6 +41,7 @@
#include "vircommand.h"
#include "configmake.h"
#include "virfile.h"
+#include "virpidfile.h"
#include "virstoragefile.h"
#include "virstring.h"
#include "cpu/cpu.h"
@@ -59,8 +60,13 @@ VIR_LOG_INIT("parallels.parallels_driver");
#define PRLCTL "prlctl"
+#define VZ_STATEDIR LOCALSTATEDIR "/run/libvirt/vz"
+
static virClassPtr vzDriverClass;
+static bool vz_driver_privileged;
+/* pid file FD, ensures two copies of the driver can't use the same root */
+static int vz_driver_lock_fd = -1;
static virMutex vz_driver_lock;
static vzDriverPtr vz_driver;
static vzConnPtr vz_conn_list;
@@ -166,6 +172,11 @@ VIR_ONCE_GLOBAL_INIT(vzDriver);
vzDriverPtr
vzGetDriverConnection(void)
{
+ if (!vz_driver_privileged) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ "%s", _("vz state driver is not active"));
+ return NULL;
+ }
virMutexLock(&vz_driver_lock);
if (!vz_driver)
vz_driver = vzDriverObjNew();
@@ -4087,18 +4098,37 @@ static virConnectDriver vzConnectDriver = {
static int
vzStateCleanup(void)
{
- virObjectUnref(vz_driver);
- vz_driver = NULL;
- virMutexDestroy(&vz_driver_lock);
- prlsdkDeinit();
+ if (vz_driver_privileged) {
+ virObjectUnref(vz_driver);
+ vz_driver = NULL;
+ if (vz_driver_lock_fd != -1)
+ virPidFileRelease(VZ_STATEDIR, "driver", vz_driver_lock_fd);
+ virMutexDestroy(&vz_driver_lock);
+ prlsdkDeinit();
+ }
return 0;
}
static int
-vzStateInitialize(bool privileged ATTRIBUTE_UNUSED,
+vzStateInitialize(bool privileged,
virStateInhibitCallback callback ATTRIBUTE_UNUSED,
void *opaque ATTRIBUTE_UNUSED)
{
+ if (!privileged)
+ return 0;
+
+ vz_driver_privileged = privileged;
+
+ if (virFileMakePathWithMode(VZ_STATEDIR, S_IRWXU) < 0) {
+ virReportSystemError(errno, _("cannot create state directory
'%s'"),
+ VZ_STATEDIR);
+ return -1;
+ }
+
+ if ((vz_driver_lock_fd =
+ virPidFileAcquire(VZ_STATEDIR, "driver", true, getpid())) < 0)
+ return -1;
+
if (prlsdkInit() < 0) {
VIR_DEBUG("%s", _("Can't initialize Parallels SDK"));
return -1;
--
2.21.0