Add locking for thread safety to nodedevice drivers

ChangeLog

@@ -1,3 +1,10 @@
+Thu Dec  4 21:48:41 GMT 2008 Daniel P. Berrange <berrange@redhat.com>
+
+	* src/libvirt_sym.version.in, src/node_device.c,
+	src/node_device.h, src/node_device_conf.h,
+	src/node_device_devkit.c, src/node_device_hal.c: Add
+	locking for thread safety of driver APIs
+
 Thu Dec  4 21:46:41 GMT 2008 Daniel P. Berrange <berrange@redhat.com>
 
 	* src/libvirt.c, src/datatypes.h, src/datatypes.c: Cache

src/libvirt_sym.version.in

@@ -510,6 +510,7 @@ LIBVIRT_PRIVATE_@VERSION@ {
 	virNodeDeviceDefFormat;
 	virNodeDeviceObjLock;
 	virNodeDeviceObjUnlock;
+	virNodeDeviceAssignDef;
 
 
 	/* qparams.h */

src/node_device.c

@@ -29,7 +29,7 @@
 #include "virterror_internal.h"
 #include "datatypes.h"
 #include "memory.h"
-
+#include "logging.h"
 #include "node_device_conf.h"
 #include "node_device.h"
 
@@ -45,6 +45,17 @@ static int dev_has_cap(const virNodeDeviceObjPtr dev, const char *cap)
 }
 
 
+void nodeDeviceLock(virDeviceMonitorStatePtr driver)
+{
+    DEBUG("LOCK node %p", driver);
+    pthread_mutex_lock(&driver->lock);
+}
+void nodeDeviceUnlock(virDeviceMonitorStatePtr driver)
+{
+    DEBUG("UNLOCK node %p", driver);
+    pthread_mutex_unlock(&driver->lock);
+}
+
 static int nodeNumOfDevices(virConnectPtr conn,
                             const char *cap,
                             unsigned int flags ATTRIBUTE_UNUSED)
@@ -71,15 +82,24 @@ nodeListDevices(virConnectPtr conn,
     int ndevs = 0;
     unsigned int i;
 
-    for (i = 0; i < driver->devs.count && ndevs < maxnames; i++)
+    nodeDeviceLock(driver);
+    for (i = 0; i < driver->devs.count && ndevs < maxnames; i++) {
+        virNodeDeviceObjLock(driver->devs.objs[i]);
         if (cap == NULL ||
-            dev_has_cap(driver->devs.objs[i], cap))
+            dev_has_cap(driver->devs.objs[i], cap)) {
-            if ((names[ndevs++] = strdup(driver->devs.objs[i]->def->name)) == NULL)
+            if ((names[ndevs++] = strdup(driver->devs.objs[i]->def->name)) == NULL) {
+                virNodeDeviceObjUnlock(driver->devs.objs[i]);
                 goto failure;
+            }
+        }
+        virNodeDeviceObjUnlock(driver->devs.objs[i]);
+    }
+    nodeDeviceUnlock(driver);
 
     return ndevs;
 
  failure:
+    nodeDeviceUnlock(driver);
     --ndevs;
     while (--ndevs >= 0)
         VIR_FREE(names[ndevs]);
@@ -94,7 +114,10 @@ static virNodeDevicePtr nodeDeviceLookupByName(virConnectPtr conn,
     virNodeDeviceObjPtr obj;
     virNodeDevicePtr ret = NULL;
 
+    nodeDeviceLock(driver);
     obj = virNodeDeviceFindByName(&driver->devs, name);
+    nodeDeviceUnlock(driver);
+
     if (!obj) {
         virNodeDeviceReportError(conn, VIR_ERR_INVALID_NODE_DEVICE,
                                  "%s", _("no node device with matching name"));
@@ -104,6 +127,8 @@ static virNodeDevicePtr nodeDeviceLookupByName(virConnectPtr conn,
     ret = virGetNodeDevice(conn, name);
 
 cleanup:
+    if (obj)
+        virNodeDeviceObjUnlock(obj);
     return ret;
 }
 
@@ -114,7 +139,10 @@ static char *nodeDeviceDumpXML(virNodeDevicePtr dev,
     virNodeDeviceObjPtr obj;
     char *ret = NULL;
 
+    nodeDeviceLock(driver);
     obj = virNodeDeviceFindByName(&driver->devs, dev->name);
+    nodeDeviceUnlock(driver);
+
     if (!obj) {
         virNodeDeviceReportError(dev->conn, VIR_ERR_INVALID_NODE_DEVICE,
                               "%s", _("no node device with matching name"));
@@ -124,6 +152,8 @@ static char *nodeDeviceDumpXML(virNodeDevicePtr dev,
     ret = virNodeDeviceDefFormat(dev->conn, obj->def);
 
 cleanup:
+    if (obj)
+        virNodeDeviceObjUnlock(obj);
     return ret;
 }
 
@@ -134,7 +164,10 @@ static char *nodeDeviceGetParent(virNodeDevicePtr dev)
     virNodeDeviceObjPtr obj;
     char *ret = NULL;
 
+    nodeDeviceLock(driver);
     obj = virNodeDeviceFindByName(&driver->devs, dev->name);
+    nodeDeviceUnlock(driver);
+
     if (!obj) {
         virNodeDeviceReportError(dev->conn, VIR_ERR_INVALID_NODE_DEVICE,
                               "%s", _("no node device with matching name"));
@@ -146,6 +179,8 @@ static char *nodeDeviceGetParent(virNodeDevicePtr dev)
         virNodeDeviceReportError(dev->conn, VIR_ERR_NO_MEMORY, NULL);
 
 cleanup:
+    if (obj)
+        virNodeDeviceObjUnlock(obj);
     return ret;
 }
 
@@ -158,7 +193,10 @@ static int nodeDeviceNumOfCaps(virNodeDevicePtr dev)
     int ncaps = 0;
     int ret = -1;
 
+    nodeDeviceLock(driver);
     obj = virNodeDeviceFindByName(&driver->devs, dev->name);
+    nodeDeviceUnlock(driver);
+
     if (!obj) {
         virNodeDeviceReportError(dev->conn, VIR_ERR_INVALID_NODE_DEVICE,
                               "%s", _("no node device with matching name"));
@@ -170,6 +208,8 @@ static int nodeDeviceNumOfCaps(virNodeDevicePtr dev)
     ret = ncaps;
 
 cleanup:
+    if (obj)
+        virNodeDeviceObjUnlock(obj);
     return ret;
 }
 
@@ -183,7 +223,10 @@ nodeDeviceListCaps(virNodeDevicePtr dev, char **const names, int maxnames)
     int ncaps = 0;
     int ret = -1;
 
+    nodeDeviceLock(driver);
     obj = virNodeDeviceFindByName(&driver->devs, dev->name);
+    nodeDeviceUnlock(driver);
+
     if (!obj) {
         virNodeDeviceReportError(dev->conn, VIR_ERR_INVALID_NODE_DEVICE,
                               "%s", _("no node device with matching name"));
@@ -198,6 +241,8 @@ nodeDeviceListCaps(virNodeDevicePtr dev, char **const names, int maxnames)
     ret = ncaps;
 
 cleanup:
+    if (obj)
+        virNodeDeviceObjUnlock(obj);
     if (ret == -1) {
         --ncaps;
         while (--ncaps >= 0)

src/node_device.h

@@ -26,6 +26,7 @@
 
 #include "internal.h"
 #include "driver.h"
+#include "node_device_conf.h"
 
 #ifdef HAVE_HAL
 int halNodeRegister(void);
@@ -34,6 +35,9 @@ int halNodeRegister(void);
 int devkitNodeRegister(void);
 #endif
 
+void nodeDeviceLock(virDeviceMonitorStatePtr driver);
+void nodeDeviceUnlock(virDeviceMonitorStatePtr driver);
+
 void registerCommonNodeFuncs(virDeviceMonitorPtr mon);
 
 int nodedevRegister(void);

src/node_device_conf.h

@@ -158,7 +158,8 @@ struct _virNodeDeviceObjList {
 typedef struct _virDeviceMonitorState virDeviceMonitorState;
 typedef virDeviceMonitorState *virDeviceMonitorStatePtr;
 struct _virDeviceMonitorState {
-    int dbusWatch;
+    PTHREAD_MUTEX_T(lock);
+
     virNodeDeviceObjList devs;		/* currently-known devices */
     void *privateData;			/* driver-specific private data */
 };

src/node_device_devkit.c

@@ -237,6 +237,7 @@ static void dev_create(void *_dkdev, void *_dkclient ATTRIBUTE_UNUSED)
     DevkitDevice *dkdev = _dkdev;
     const char *sysfs_path = devkit_device_get_native_path(dkdev);
     virNodeDeviceObjPtr dev = NULL;
+    virNodeDeviceDefPtr def = NULL;
     const char *name;
     int rv;
 
@@ -250,31 +251,39 @@ static void dev_create(void *_dkdev, void *_dkclient ATTRIBUTE_UNUSED)
     else
         ++name;
 
-    if (VIR_ALLOC(dev) < 0 || VIR_ALLOC(dev->def) < 0)
+    if (VIR_ALLOC(def) < 0)
         goto failure;
 
-    dev->privateData = dkdev;
+    if ((def->name = strdup(name)) == NULL)
-
-    if ((dev->def->name = strdup(name)) == NULL)
         goto failure;
 
     // TODO: Find device parent, if any
 
-    rv = gather_capabilities(dkdev, &dev->def->caps);
+    rv = gather_capabilities(dkdev, &def->caps);
     if (rv != 0) goto failure;
 
-    if (VIR_REALLOC_N(driverState->devs.objs, driverState->devs.count + 1) < 0)
+    nodeDeviceLock(driverState);
-        goto failure;
+    dev = virNodeDeviceAssignDef(NULL,
+                                 &driverState->devs,
+                                 def);
 
-    driverState->devs.objs[driverState->devs.count++] = dev;
+    if (!dev) {
+        nodeDeviceUnlock(driverState);
+        goto failure;
+    }
+
+    dev->privateData = dkdev;
+    dev->privateFree = NULL; /* XXX some free func needed ? */
+    virNodeDeviceObjUnlock(dev);
+
+    nodeDeviceUnlock(driverState);
 
     return;
 
  failure:
     DEBUG("FAILED TO ADD dev %s", name);
-    if (dev)
+    if (def)
-        virNodeDeviceDefFree(dev->def);
+        virNodeDeviceDefFree(def);
-    VIR_FREE(dev);
 }
 
 
@@ -292,8 +301,8 @@ static int devkitDeviceMonitorStartup(void)
     if (VIR_ALLOC(driverState) < 0)
         return -1;
 
-    // TODO: Is it really ok to call this multiple times??
+    pthread_mutex_init(&driverState->lock, NULL);
-    //       Is there something analogous to call on close?
+
     g_type_init();
 
     /* Get new devkit_client and connect to daemon */
@@ -362,10 +371,14 @@ static int devkitDeviceMonitorStartup(void)
 static int devkitDeviceMonitorShutdown(void)
 {
     if (driverState) {
-        DevkitClient *devkit_client = DRV_STATE_DKCLIENT(driverState);
+        DevkitClient *devkit_client;
+
+        nodeDeviceLock(driverState);
+        devkit_client = DRV_STATE_DKCLIENT(driverState);
         virNodeDeviceObjListFree(&driverState->devs);
         if (devkit_client)
             g_object_unref(devkit_client);
+        nodeDeviceLock(driverState);
         VIR_FREE(driverState);
         return 0;
     }
@@ -375,6 +388,8 @@ static int devkitDeviceMonitorShutdown(void)
 
 static int devkitDeviceMonitorReload(void)
 {
+    /* XXX This isn't thread safe because its free'ing the thing
+     * we're locking */
     (void)devkitDeviceMonitorShutdown();
     return devkitDeviceMonitorStartup();
 }

src/node_device_hal.c

@@ -403,53 +403,62 @@ static void free_udi(void *udi)
     VIR_FREE(udi);
 }
 
-static void dev_create(char *udi)
+static void dev_create(const char *udi)
 {
-    LibHalContext *ctx = DRV_STATE_HAL_CTX(driverState);
+    LibHalContext *ctx;
     char *parent_key = NULL;
-    virNodeDeviceObjPtr dev;
+    virNodeDeviceObjPtr dev = NULL;
+    virNodeDeviceDefPtr def = NULL;
     const char *name = hal_name(udi);
     int rv;
+    char *privData = strdup(udi);
 
-    if (VIR_ALLOC(dev) < 0 || VIR_ALLOC(dev->def) < 0)
+    if (!privData)
+        return;
+
+    nodeDeviceLock(driverState);
+    ctx = DRV_STATE_HAL_CTX(driverState);
+
+    if (VIR_ALLOC(def) < 0)
         goto failure;
 
-    dev->privateData = udi;
+    if ((def->name = strdup(name)) == NULL)
-    dev->privateFree = free_udi;
-
-    if ((dev->def->name = strdup(name)) == NULL)
         goto failure;
 
     if (get_str_prop(ctx, udi, "info.parent", &parent_key) == 0) {
-        dev->def->parent = strdup(hal_name(parent_key));
+        def->parent = strdup(hal_name(parent_key));
         VIR_FREE(parent_key);
-        if (dev->def->parent == NULL)
+        if (def->parent == NULL)
             goto failure;
     }
 
-    rv = gather_capabilities(ctx, udi, &dev->def->caps);
+    rv = gather_capabilities(ctx, udi, &def->caps);
     if (rv != 0) goto failure;
 
-    if (dev->def->caps == NULL) {
+    if (def->caps == NULL)
-        virNodeDeviceDefFree(dev->def);
+        goto cleanup;
-        VIR_FREE(dev);
-        VIR_FREE(udi);
-        return;
-    }
 
-    if (VIR_REALLOC_N(driverState->devs.objs, driverState->devs.count + 1) < 0)
+    dev = virNodeDeviceAssignDef(NULL,
+                                 &driverState->devs,
+                                 def);
+
+    if (!dev)
         goto failure;
 
-    driverState->devs.objs[driverState->devs.count++] = dev;
+    dev->privateData = privData;
+    dev->privateFree = free_udi;
+    virNodeDeviceObjUnlock(dev);
 
+    nodeDeviceUnlock(driverState);
     return;
 
  failure:
     DEBUG("FAILED TO ADD dev %s", name);
-    if (dev)
+cleanup:
-        virNodeDeviceDefFree(dev->def);
+    VIR_FREE(privData);
-    VIR_FREE(dev);
+    if (def)
-    VIR_FREE(udi);
+        virNodeDeviceDefFree(def);
+    nodeDeviceUnlock(driverState);
 }
 
 
@@ -457,7 +466,7 @@ static void device_added(LibHalContext *ctx ATTRIBUTE_UNUSED,
                          const char *udi)
 {
     DEBUG0(hal_name(udi));
-    dev_create(strdup(udi));
+    dev_create(udi);
 }
 
 
@@ -465,12 +474,16 @@ static void device_removed(LibHalContext *ctx ATTRIBUTE_UNUSED,
                            const char *udi)
 {
     const char *name = hal_name(udi);
-    virNodeDeviceObjPtr dev = virNodeDeviceFindByName(&driverState->devs,name);
+    virNodeDeviceObjPtr dev;
+
+    nodeDeviceLock(driverState);
+    dev = virNodeDeviceFindByName(&driverState->devs,name);
     DEBUG0(name);
     if (dev)
         virNodeDeviceObjRemove(&driverState->devs, dev);
     else
         DEBUG("no device named %s", name);
+    nodeDeviceUnlock(driverState);
 }
 
 
@@ -478,12 +491,18 @@ static void device_cap_added(LibHalContext *ctx,
                              const char *udi, const char *cap)
 {
     const char *name = hal_name(udi);
-    virNodeDeviceObjPtr dev = virNodeDeviceFindByName(&driverState->devs,name);
+    virNodeDeviceObjPtr dev;
+
+    nodeDeviceLock(driverState);
+    dev = virNodeDeviceFindByName(&driverState->devs,name);
+    nodeDeviceUnlock(driverState);
     DEBUG("%s %s", cap, name);
-    if (dev)
+    if (dev) {
         (void)gather_capability(ctx, udi, cap, &dev->def->caps);
-    else
+        virNodeDeviceObjUnlock(dev);
+    } else {
         DEBUG("no device named %s", name);
+    }
 }
 
 
@@ -492,16 +511,20 @@ static void device_cap_lost(LibHalContext *ctx ATTRIBUTE_UNUSED,
                             const char *cap)
 {
     const char *name = hal_name(udi);
-    virNodeDeviceObjPtr dev = virNodeDeviceFindByName(&driverState->devs,name);
+    virNodeDeviceObjPtr dev;
+
+    nodeDeviceLock(driverState);
+    dev = virNodeDeviceFindByName(&driverState->devs,name);
     DEBUG("%s %s", cap, name);
     if (dev) {
         /* Simply "rediscover" device -- incrementally handling changes
          * to sub-capabilities (like net.80203) is nasty ... so avoid it.
          */
         virNodeDeviceObjRemove(&driverState->devs, dev);
-        dev_create(strdup(udi));
+        dev_create(udi);
     } else
         DEBUG("no device named %s", name);
+    nodeDeviceUnlock(driverState);
 }
 
 
@@ -512,7 +535,10 @@ static void device_prop_modified(LibHalContext *ctx ATTRIBUTE_UNUSED,
                                  dbus_bool_t is_added ATTRIBUTE_UNUSED)
 {
     const char *name = hal_name(udi);
-    virNodeDeviceObjPtr dev = virNodeDeviceFindByName(&driverState->devs,name);
+    virNodeDeviceObjPtr dev;
+
+    nodeDeviceLock(driverState);
+    dev = virNodeDeviceFindByName(&driverState->devs,name);
     DEBUG("%s %s", key, name);
     if (dev) {
         /* Simply "rediscover" device -- incrementally handling changes
@@ -520,9 +546,10 @@ static void device_prop_modified(LibHalContext *ctx ATTRIBUTE_UNUSED,
          * specific ways) is nasty ... so avoid it.
          */
         virNodeDeviceObjRemove(&driverState->devs, dev);
-        dev_create(strdup(udi));
+        dev_create(udi);
     } else
         DEBUG("no device named %s", name);
+    nodeDeviceUnlock(driverState);
 }
 
 
@@ -531,8 +558,8 @@ static void dbus_watch_callback(int fdatch ATTRIBUTE_UNUSED,
                                 int events, void *opaque)
 {
     DBusWatch *watch = opaque;
-    LibHalContext *hal_ctx = DRV_STATE_HAL_CTX(driverState);
+    LibHalContext *hal_ctx;
-    DBusConnection *dbus_conn = libhal_ctx_get_dbus_connection(hal_ctx);
+    DBusConnection *dbus_conn;
     int dbus_flags = 0;
 
     if (events & VIR_EVENT_HANDLE_READABLE)
@@ -546,6 +573,10 @@ static void dbus_watch_callback(int fdatch ATTRIBUTE_UNUSED,
 
     (void)dbus_watch_handle(watch, dbus_flags);
 
+    nodeDeviceLock(driverState);
+    hal_ctx = DRV_STATE_HAL_CTX(driverState);
+    dbus_conn = libhal_ctx_get_dbus_connection(hal_ctx);
+    nodeDeviceUnlock(driverState);
     while (dbus_connection_dispatch(dbus_conn) == DBUS_DISPATCH_DATA_REMAINS)
         /* keep dispatching while data remains */;
 }
@@ -566,42 +597,63 @@ static int xlate_dbus_watch_flags(int dbus_flags)
 }
 
 
+struct nodeDeviceWatchInfo
+{
+    int watch;
+};
+
+static void nodeDeviceWatchFree(void *data) {
+    struct nodeDeviceWatchInfo *info = data;
+    VIR_FREE(info);
+}
+
 static dbus_bool_t add_dbus_watch(DBusWatch *watch,
-                                  void *data)
+                                  void *data ATTRIBUTE_UNUSED)
 {
     int flags = 0;
-    virDeviceMonitorStatePtr state = data;
+    struct nodeDeviceWatchInfo *info;
+
+    if (VIR_ALLOC(info) < 0)
+        return 0;
 
     if (dbus_watch_get_enabled(watch))
         flags = xlate_dbus_watch_flags(dbus_watch_get_flags(watch));
 
-    if ((state->dbusWatch =
+    info->watch = virEventAddHandle(dbus_watch_get_unix_fd(watch), flags,
-         virEventAddHandle(dbus_watch_get_unix_fd(watch), flags,
+                                    dbus_watch_callback, watch, NULL);
-                           dbus_watch_callback, watch, NULL)) < 0)
+    if (info->watch < 0) {
+        VIR_FREE(info);
         return 0;
+    }
+    dbus_watch_set_data(watch, info, nodeDeviceWatchFree);
+
     return 1;
 }
 
 
-static void remove_dbus_watch(DBusWatch *watch ATTRIBUTE_UNUSED,
+static void remove_dbus_watch(DBusWatch *watch,
-                              void *data)
+                              void *data ATTRIBUTE_UNUSED)
 {
-    virDeviceMonitorStatePtr state = data;
+    struct nodeDeviceWatchInfo *info;
 
-    (void)virEventRemoveHandle(state->dbusWatch);
+    info = dbus_watch_get_data(watch);
+
+    (void)virEventRemoveHandle(info->watch);
 }
 
 
 static void toggle_dbus_watch(DBusWatch *watch,
-                              void *data)
+                              void *data ATTRIBUTE_UNUSED)
 {
     int flags = 0;
-    virDeviceMonitorStatePtr state = data;
+    struct nodeDeviceWatchInfo *info;
 
     if (dbus_watch_get_enabled(watch))
         flags = xlate_dbus_watch_flags(dbus_watch_get_flags(watch));
 
-    (void)virEventUpdateHandle(state->dbusWatch, flags);
+    info = dbus_watch_get_data(watch);
+
+    (void)virEventUpdateHandle(info->watch, flags);
 }
 
 
@@ -620,6 +672,9 @@ static int halDeviceMonitorStartup(void)
     if (VIR_ALLOC(driverState) < 0)
         return -1;
 
+    pthread_mutex_init(&driverState->lock, NULL);
+    nodeDeviceLock(driverState);
+
     /* Allocate and initialize a new HAL context */
     dbus_error_init(&err);
     hal_ctx = libhal_ctx_new();
@@ -647,7 +702,7 @@ static int halDeviceMonitorStartup(void)
                                              add_dbus_watch,
                                              remove_dbus_watch,
                                              toggle_dbus_watch,
-                                             driverState, NULL)) {
+                                             NULL, NULL)) {
         fprintf(stderr, "%s: dbus_connection_set_watch_functions failed\n",
                 __FUNCTION__);
         goto failure;
@@ -665,14 +720,18 @@ static int halDeviceMonitorStartup(void)
 
     /* Populate with known devices */
     driverState->privateData = hal_ctx;
+
+    nodeDeviceUnlock(driverState);
     udi = libhal_get_all_devices(hal_ctx, &num_devs, &err);
     if (udi == NULL) {
         fprintf(stderr, "%s: libhal_get_all_devices failed\n", __FUNCTION__);
         goto failure;
     }
-    for (i = 0; i < num_devs; i++)
+    for (i = 0; i < num_devs; i++) {
         dev_create(udi[i]);
-    free(udi);
+        VIR_FREE(udi[i]);
+    }
+    VIR_FREE(udi);
 
     return 0;
 
@@ -686,9 +745,10 @@ static int halDeviceMonitorStartup(void)
         (void)libhal_ctx_free(hal_ctx);
     if (udi) {
         for (i = 0; i < num_devs; i++)
-            free(udi[i]);
+            VIR_FREE(udi[i]);
-        free(udi);
+        VIR_FREE(udi);
     }
+    nodeDeviceUnlock(driverState);
     VIR_FREE(driverState);
 
     return -1;
@@ -698,10 +758,12 @@ static int halDeviceMonitorStartup(void)
 static int halDeviceMonitorShutdown(void)
 {
     if (driverState) {
+        nodeDeviceLock(driverState);
         LibHalContext *hal_ctx = DRV_STATE_HAL_CTX(driverState);
         virNodeDeviceObjListFree(&driverState->devs);
         (void)libhal_ctx_shutdown(hal_ctx, NULL);
         (void)libhal_ctx_free(hal_ctx);
+        nodeDeviceUnlock(driverState);
         VIR_FREE(driverState);
         return 0;
     }
@@ -711,6 +773,8 @@ static int halDeviceMonitorShutdown(void)
 
 static int halDeviceMonitorReload(void)
 {
+    /* XXX This isn't thread safe because its free'ing the thing
+     * we're locking */
     (void)halDeviceMonitorShutdown();
     return halDeviceMonitorStartup();
 }