10:47 a.m.
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/interface/driver.pid
In unprivileged libvirtd this ends up locking
/run/user/$UID/libvirt/interface/run/driver.pid
NB, the latter can vary depending on $XDG_RUNTIME_DIR
Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com>
---
src/interface/interface_backend_netcf.c | 45 +++++++++++++++++++++++--
src/interface/interface_backend_udev.c | 44 +++++++++++++++++++++++-
2 files changed, 85 insertions(+), 4 deletions(-)
diff --git a/src/interface/interface_backend_netcf.c
b/src/interface/interface_backend_netcf.c
index cf8eb9488d..868e49c56e 100644
--- a/src/interface/interface_backend_netcf.c
+++ b/src/interface/interface_backend_netcf.c
@@ -29,10 +29,14 @@
#include "interface_conf.h"
#include "viralloc.h"
#include "virlog.h"
+#include "virfile.h"
+#include "virpidfile.h"
#include "virstring.h"
#include "viraccessapicheck.h"
#include "virinterfaceobj.h"
+#include "configmake.h"
+
#define VIR_FROM_THIS VIR_FROM_INTERFACE
VIR_LOG_INIT("interface.interface_backend_netcf");
@@ -43,6 +47,10 @@ VIR_LOG_INIT("interface.interface_backend_netcf");
typedef struct
{
virObjectLockable parent;
+ /* pid file FD, ensures two copies of the driver can't use the same root */
+ int lockFD;
+
+ char *stateDir;
struct netcf *netcf;
bool privileged;
} virNetcfDriverState, *virNetcfDriverStatePtr;
@@ -71,6 +79,11 @@ virNetcfDriverStateDispose(void *obj)
if (_driver->netcf)
ncf_close(_driver->netcf);
+
+ if (_driver->lockFD != -1)
+ virPidFileRelease(_driver->stateDir, "driver", _driver->lockFD);
+
+ VIR_FREE(_driver->stateDir);
}
@@ -87,15 +100,41 @@ netcfStateInitialize(bool privileged,
driver->privileged = privileged;
+ if (privileged) {
+ if (virAsprintf(&driver->stateDir,
+ "%s/run/libvirt/nodedev", LOCALSTATEDIR) < 0)
+ goto error;
+ } else {
+ VIR_AUTOFREE(char *) rundir = NULL;
+
+ if (!(rundir = virGetUserRuntimeDirectory()))
+ goto error;
+ if (virAsprintf(&driver->stateDir, "%s/nodedev/run", rundir)
< 0)
+ goto error;
+ }
+
+ if (virFileMakePathWithMode(driver->stateDir, S_IRWXU) < 0) {
+ virReportSystemError(errno, _("cannot create state directory
'%s'"),
+ driver->stateDir);
+ goto error;
+ }
+
+ if ((driver->lockFD =
+ virPidFileAcquire(driver->stateDir, "driver", true, getpid())) <
0)
+ goto error;
+
/* open netcf */
if (ncf_init(&driver->netcf, NULL) != 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to initialize netcf"));
- virObjectUnref(driver);
- driver = NULL;
- return -1;
+ goto error;
}
return 0;
+
+ error:
+ virObjectUnref(driver);
+ driver = NULL;
+ return -1;
}
diff --git a/src/interface/interface_backend_udev.c
b/src/interface/interface_backend_udev.c
index 1373356246..fcd7f1c04a 100644
--- a/src/interface/interface_backend_udev.c
+++ b/src/interface/interface_backend_udev.c
@@ -32,14 +32,21 @@
#include "interface_conf.h"
#include "viralloc.h"
#include "virstring.h"
+#include "virpidfile.h"
#include "viraccessapicheck.h"
#include "virinterfaceobj.h"
#include "virnetdev.h"
+#include "configmake.h"
+
#define VIR_FROM_THIS VIR_FROM_INTERFACE
struct udev_iface_driver {
struct udev *udev;
+ /* pid file FD, ensures two copies of the driver can't use the same root */
+ int lockFD;
+
+ char *stateDir;
bool privileged;
};
@@ -1157,6 +1164,9 @@ udevInterfaceIsActive(virInterfacePtr ifinfo)
}
+static int
+udevStateCleanup(void);
+
static int
udevStateInitialize(bool privileged,
virStateInhibitCallback callback ATTRIBUTE_UNUSED,
@@ -1167,6 +1177,31 @@ udevStateInitialize(bool privileged,
if (VIR_ALLOC(driver) < 0)
goto cleanup;
+ driver->lockFD = -1;
+
+ if (privileged) {
+ if (virAsprintf(&driver->stateDir,
+ "%s/run/libvirt/nodedev", LOCALSTATEDIR) < 0)
+ goto cleanup;
+ } else {
+ VIR_AUTOFREE(char *) rundir = NULL;
+
+ if (!(rundir = virGetUserRuntimeDirectory()))
+ goto cleanup;
+ if (virAsprintf(&driver->stateDir, "%s/nodedev/run", rundir)
< 0)
+ goto cleanup;
+ }
+
+ if (virFileMakePathWithMode(driver->stateDir, S_IRWXU) < 0) {
+ virReportSystemError(errno, _("cannot create state directory
'%s'"),
+ driver->stateDir);
+ goto cleanup;
+ }
+
+ if ((driver->lockFD =
+ virPidFileAcquire(driver->stateDir, "driver", true, getpid())) <
0)
+ goto cleanup;
+
driver->udev = udev_new();
if (!driver->udev) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
@@ -1178,6 +1213,8 @@ udevStateInitialize(bool privileged,
ret = 0;
cleanup:
+ if (ret < 0)
+ udevStateCleanup();
return ret;
}
@@ -1187,8 +1224,13 @@ udevStateCleanup(void)
if (!driver)
return -1;
- udev_unref(driver->udev);
+ if (driver->udev)
+ udev_unref(driver->udev);
+
+ if (driver->lockFD != -1)
+ virPidFileRelease(driver->stateDir, "driver", driver->lockFD);
+ VIR_FREE(driver->stateDir);
VIR_FREE(driver);
return 0;
}
--
2.21.0