[libvirt] [PATCH] Make virInitialize thread safe
Daniel P. Berrange
berrange at redhat.com
Wed Oct 10 15:13:35 UTC 2012
From: "Daniel P. Berrange" <berrange at redhat.com>
Currently there is a restriction that multi-threaded applications
must manually call virInitialize, before threads start using
libvirt, because it is not thread-safe. By switching it to use
a virOnceControl initializer we gain thread safety, and thus
applications no longer need to manually call it. They can rely
on virConnectOpen invoking it for them.
Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
src/libvirt.c | 139 ++++++++++++++++++++++++++++++----------------------------
1 file changed, 71 insertions(+), 68 deletions(-)
diff --git a/src/libvirt.c b/src/libvirt.c
index 76e4401..b616f41 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -59,6 +59,7 @@
#include "command.h"
#include "virrandom.h"
#include "viruri.h"
+#include "threads.h"
#ifdef WITH_TEST
# include "test/test_driver.h"
@@ -119,7 +120,7 @@ static int virNWFilterDriverTabCount = 0;
static virStateDriverPtr virStateDriverTab[MAX_DRIVERS];
static int virStateDriverTabCount = 0;
#endif
-static int initialized = 0;
+
#if defined(POLKIT_AUTH)
static int virConnectAuthGainPolkit(const char *privilege) {
@@ -391,29 +392,16 @@ static struct gcry_thread_cbs virTLSThreadImpl = {
} \
} while (0)
-/**
- * virInitialize:
- *
- * Initialize the library. It's better to call this routine at startup
- * in multithreaded applications to avoid potential race when initializing
- * the library.
- *
- * Calling virInitialize is mandatory, unless your first API call is one of
- * virConnectOpen*.
- *
- * Returns 0 in case of success, -1 in case of error
- */
-int
-virInitialize(void)
-{
- if (initialized)
- return 0;
- initialized = 1;
+static bool virGlobalError = false;
+static virOnceControl virGlobalOnce = VIR_ONCE_CONTROL_INITIALIZER;
+static void
+virGlobalInit(void)
+{
if (virThreadInitialize() < 0 ||
virErrorInitialize() < 0)
- return -1;
+ goto error;
gcry_control(GCRYCTL_SET_THREAD_CBS, &virTLSThreadImpl);
gcry_check_version(NULL);
@@ -429,47 +417,87 @@ virInitialize(void)
VIR_DEBUG("register drivers");
#if HAVE_WINSOCK2_H
- if (winsock_init () == -1) return -1;
+ if (winsock_init () == -1)
+ goto error;
#endif
if (!bindtextdomain(PACKAGE, LOCALEDIR))
- return -1;
+ goto error;
/*
* Note that the order is important: the first ones have a higher
* priority when calling virConnectOpen.
*/
#ifdef WITH_TEST
- if (testRegister() == -1) return -1;
+ if (testRegister() == -1)
+ goto error;
#endif
#ifdef WITH_OPENVZ
- if (openvzRegister() == -1) return -1;
+ if (openvzRegister() == -1)
+ goto error;
#endif
#ifdef WITH_VMWARE
- if (vmwareRegister() == -1) return -1;
+ if (vmwareRegister() == -1)
+ goto error;
#endif
#ifdef WITH_PHYP
- if (phypRegister() == -1) return -1;
+ if (phypRegister() == -1)
+ goto error;
#endif
#ifdef WITH_VBOX
- if (vboxRegister() == -1) return -1;
+ if (vboxRegister() == -1)
+ goto error;
#endif
#ifdef WITH_ESX
- if (esxRegister() == -1) return -1;
+ if (esxRegister() == -1)
+ goto error;
#endif
#ifdef WITH_HYPERV
- if (hypervRegister() == -1) return -1;
+ if (hypervRegister() == -1)
+ goto error;
#endif
#ifdef WITH_XENAPI
- if (xenapiRegister() == -1) return -1;
+ if (xenapiRegister() == -1)
+ goto error;
#endif
#ifdef WITH_PARALLELS
- if (parallelsRegister() == -1) return -1;
+ if (parallelsRegister() == -1)
+ goto error;
#endif
#ifdef WITH_REMOTE
- if (remoteRegister () == -1) return -1;
+ if (remoteRegister () == -1)
+ goto error;
#endif
+ return;
+
+error:
+ virGlobalError = true;
+}
+
+/**
+ * virInitialize:
+ *
+ * Initialize the library.
+ *
+ * This method is invoked automatically by any of the virConnectOpen API
+ * calls. Since release 1.0.0, there is no need to call this method even
+ * in a multithreaded application, since initialization is performed in
+ * a thread safe manner.
+ *
+ * The only time it would be neccessary to call virInitialize is if the
+ * application did not invoke virConnectOpen as its first API call.
+ *
+ * Returns 0 in case of success, -1 in case of error
+ */
+int
+virInitialize(void)
+{
+ if (virOnce(&virGlobalOnce, virGlobalInit) < 0)
+ return -1;
+
+ if (virGlobalError)
+ return -1;
return 0;
}
@@ -553,9 +581,6 @@ DllMain (HINSTANCE instance ATTRIBUTE_UNUSED,
int
virRegisterNetworkDriver(virNetworkDriverPtr driver)
{
- if (virInitialize() < 0)
- return -1;
-
virCheckNonNullArgReturn(driver, -1);
if (virNetworkDriverTabCount >= MAX_DRIVERS) {
@@ -583,9 +608,6 @@ virRegisterNetworkDriver(virNetworkDriverPtr driver)
int
virRegisterInterfaceDriver(virInterfaceDriverPtr driver)
{
- if (virInitialize() < 0)
- return -1;
-
virCheckNonNullArgReturn(driver, -1);
if (virInterfaceDriverTabCount >= MAX_DRIVERS) {
@@ -613,9 +635,6 @@ virRegisterInterfaceDriver(virInterfaceDriverPtr driver)
int
virRegisterStorageDriver(virStorageDriverPtr driver)
{
- if (virInitialize() < 0)
- return -1;
-
virCheckNonNullArgReturn(driver, -1);
if (virStorageDriverTabCount >= MAX_DRIVERS) {
@@ -643,9 +662,6 @@ virRegisterStorageDriver(virStorageDriverPtr driver)
int
virRegisterDeviceMonitor(virDeviceMonitorPtr driver)
{
- if (virInitialize() < 0)
- return -1;
-
virCheckNonNullArgReturn(driver, -1);
if (virDeviceMonitorTabCount >= MAX_DRIVERS) {
@@ -673,9 +689,6 @@ virRegisterDeviceMonitor(virDeviceMonitorPtr driver)
int
virRegisterSecretDriver(virSecretDriverPtr driver)
{
- if (virInitialize() < 0)
- return -1;
-
virCheckNonNullArgReturn(driver, -1);
if (virSecretDriverTabCount >= MAX_DRIVERS) {
@@ -703,9 +716,6 @@ virRegisterSecretDriver(virSecretDriverPtr driver)
int
virRegisterNWFilterDriver(virNWFilterDriverPtr driver)
{
- if (virInitialize() < 0)
- return -1;
-
virCheckNonNullArgReturn(driver, -1);
if (virNWFilterDriverTabCount >= MAX_DRIVERS) {
@@ -736,9 +746,6 @@ virRegisterDriver(virDriverPtr driver)
{
VIR_DEBUG("driver=%p name=%s", driver, driver ? NULLSTR(driver->name) : "(null)");
- if (virInitialize() < 0)
- return -1;
-
virCheckNonNullArgReturn(driver, -1);
if (virDriverTabCount >= MAX_DRIVERS) {
@@ -767,9 +774,6 @@ virRegisterDriver(virDriverPtr driver)
int
virRegisterStateDriver(virStateDriverPtr driver)
{
- if (virInitialize() < 0)
- return -1;
-
virCheckNonNullArgReturn(driver, -1);
if (virStateDriverTabCount >= MAX_DRIVERS) {
@@ -895,9 +899,8 @@ virGetVersion(unsigned long *libVer, const char *type ATTRIBUTE_UNUSED,
{
VIR_DEBUG("libVir=%p, type=%s, typeVer=%p", libVer, type, typeVer);
- if (!initialized)
- if (virInitialize() < 0)
- goto error;
+ if (virInitialize() < 0)
+ goto error;
if (libVer == NULL)
goto error;
@@ -1332,9 +1335,9 @@ virConnectPtr
virConnectOpen (const char *name)
{
virConnectPtr ret = NULL;
- if (!initialized)
- if (virInitialize() < 0)
- goto error;
+
+ if (virInitialize() < 0)
+ goto error;
VIR_DEBUG("name=%s", name);
virResetLastError();
@@ -1367,9 +1370,9 @@ virConnectPtr
virConnectOpenReadOnly(const char *name)
{
virConnectPtr ret = NULL;
- if (!initialized)
- if (virInitialize() < 0)
- goto error;
+
+ if (virInitialize() < 0)
+ goto error;
VIR_DEBUG("name=%s", name);
virResetLastError();
@@ -1406,9 +1409,9 @@ virConnectOpenAuth(const char *name,
unsigned int flags)
{
virConnectPtr ret = NULL;
- if (!initialized)
- if (virInitialize() < 0)
- goto error;
+
+ if (virInitialize() < 0)
+ goto error;
VIR_DEBUG("name=%s, auth=%p, flags=%x", NULLSTR(name), auth, flags);
virResetLastError();
--
1.7.11.2
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