[libvirt] [PATCH] Make virInitialize thread safe

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; 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(a)redhat.com&gt; --- 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