Re: [libvirt] [PATCH 4/9] admin: Add support for connection close callbacks

As we need a client disconnect handler, we need a mechanism to register such handlers for a client. --- include/libvirt/libvirt-admin.h | 19 ++++++ src/datatypes.c | 22 +++++++ src/datatypes.h | 14 +++- src/libvirt-admin.c | 142 ++++++++++++++++++++++++++++++++++++++++ src/libvirt_admin_public.syms | 2 + tools/virt-admin.c | 5 ++ 6 files changed, 203 insertions(+), 1 deletion(-) diff --git a/include/libvirt/libvirt-admin.h b/include/libvirt/libvirt-admin.h index 72671c6..4539ac6 100644 --- a/include/libvirt/libvirt-admin.h +++ b/include/libvirt/libvirt-admin.h @@ -54,6 +54,25 @@ int virAdmConnectClose(virAdmConnectPtr conn); int virAdmConnectRef(virAdmConnectPtr conn); int virAdmConnectIsAlive(virAdmConnectPtr conn); +/** + * virAdmConnectCloseFunc: + * @conn: virAdmConnect connection + * @reason: reason why the connection was closed (see virConnectCloseReason) + * @opaque: opaque client data + * + * A callback to be registered, in case a connection was closed. + */ +typedef void (*virAdmConnectCloseFunc)(virAdmConnectPtr conn, + int reason, + void *opaque); + +int virAdmConnectRegisterCloseCallback(virAdmConnectPtr conn, + virAdmConnectCloseFunc cb, + void *opaque, + virFreeCallback freecb); +int virAdmConnectUnregisterCloseCallback(virAdmConnectPtr conn, + virAdmConnectCloseFunc cb); + # ifdef __cplusplus } # endif diff --git a/src/datatypes.c b/src/datatypes.c index 12bcfc1..9e374e4 100644 --- a/src/datatypes.c +++ b/src/datatypes.c @@ -60,8 +60,10 @@ static void virStorageVolDispose(void *obj); static void virStoragePoolDispose(void *obj); virClassPtr virAdmConnectClass; +virClassPtr virAdmConnectCloseCallbackDataClass; static void virAdmConnectDispose(void *obj); +static void virAdmConnectCloseCallbackDataDispose(void *obj); static int virDataTypesOnceInit(void) @@ -91,6 +93,7 @@ virDataTypesOnceInit(void) DECLARE_CLASS(virStoragePool); DECLARE_CLASS_LOCKABLE(virAdmConnect); + DECLARE_CLASS_LOCKABLE(virAdmConnectCloseCallbackData); #undef DECLARE_CLASS_COMMON #undef DECLARE_CLASS_LOCKABLE @@ -822,6 +825,9 @@ virAdmConnectNew(void) if (!(ret = virObjectLockableNew(virAdmConnectClass))) return NULL; + if (!(ret->closeCallback = virObjectLockableNew(virAdmConnectCloseCallbackDataClass))) + return NULL; + return ret; } @@ -832,4 +838,20 @@ virAdmConnectDispose(void *obj) if (conn->privateDataFreeFunc) conn->privateDataFreeFunc(conn); + + virObjectUnref(conn->closeCallback); +} + +static void +virAdmConnectCloseCallbackDataDispose(void *obj) +{ + virAdmConnectCloseCallbackDataPtr cb_data = obj; + + virObjectLock(cb_data); + + cb_data->callback = NULL;

+ if (cb_data->freeCallback) + cb_data->freeCallback(cb_data->opaque); + + virObjectUnlock(cb_data); } diff --git a/src/datatypes.h b/src/datatypes.h index be108fe..33df476 100644 --- a/src/datatypes.h +++ b/src/datatypes.h @@ -331,9 +331,11 @@ extern virClassPtr virAdmConnectClass; typedef struct _virConnectCloseCallbackData virConnectCloseCallbackData; typedef virConnectCloseCallbackData *virConnectCloseCallbackDataPtr; +typedef struct _virAdmConnectCloseCallbackData virAdmConnectCloseCallbackData; +typedef virAdmConnectCloseCallbackData *virAdmConnectCloseCallbackDataPtr; /** - * Internal structure holding data related to connection close callbacks. + * Internal structures holding data related to connection close callbacks. */ struct _virConnectCloseCallbackData { virObjectLockable parent; @@ -344,6 +346,15 @@ struct _virConnectCloseCallbackData { virFreeCallback freeCallback; }; +struct _virAdmConnectCloseCallbackData { + virObjectLockable parent; + + virAdmConnectPtr conn; + virAdmConnectCloseFunc callback; + void *opaque; + virFreeCallback freeCallback; +}; + /** * _virConnect: * @@ -400,6 +411,7 @@ struct _virAdmConnect { void *privateData; virFreeCallback privateDataFreeFunc; + virAdmConnectCloseCallbackDataPtr closeCallback; }; diff --git a/src/libvirt-admin.c b/src/libvirt-admin.c index e12e2b8..9ad124e 100644 --- a/src/libvirt-admin.c +++ b/src/libvirt-admin.c @@ -64,9 +64,31 @@ remoteAdminPrivDispose(void *opaque) remoteAdminPrivPtr priv = opaque; virObjectUnref(priv->program); + virNetClientClose(priv->client); virObjectUnref(priv->client); } +static void +remoteAdminClientCloseFunc(virNetClientPtr client ATTRIBUTE_UNUSED, + int reason, + void *opaque) +{ + virAdmConnectCloseCallbackDataPtr cbdata = opaque; + + virObjectLock(cbdata); + + if (cbdata->callback) { + VIR_DEBUG("Triggering connection close callback %p reason=%d, opaque=%p", + cbdata->callback, reason, cbdata->opaque); + cbdata->callback(cbdata->conn, reason, cbdata->opaque); + + if (cbdata->freeCallback) + cbdata->freeCallback(cbdata->opaque); + cbdata->callback = NULL; + cbdata->freeCallback = NULL; + } + virObjectUnlock(cbdata); +}

static int callFull(virAdmConnectPtr conn ATTRIBUTE_UNUSED, @@ -137,6 +159,11 @@ remoteAdminConnectOpen(virAdmConnectPtr conn, unsigned int flags) args.flags = flags; + virObjectRef(conn->closeCallback); + virNetClientSetCloseCallback(priv->client, remoteAdminClientCloseFunc, + conn->closeCallback, + virObjectFreeCallback); + if (call(conn, 0, ADMIN_PROC_CONNECT_OPEN, (xdrproc_t)xdr_admin_connect_open_args, (char *)&args, (xdrproc_t)xdr_void, (char *)NULL) == -1) { @@ -164,6 +191,9 @@ remoteAdminConnectClose(virAdmConnectPtr conn) goto done; } + virNetClientSetCloseCallback(priv->client, NULL, conn->closeCallback, + virObjectFreeCallback); + rv = 0; done: @@ -462,3 +492,115 @@ virAdmConnectIsAlive(virAdmConnectPtr conn) else return 0; } + +/** + * virAdmConnectRegisterCloseCallback: + * @conn: connection to admin server + * @cb: callback to be invoked upon connection close + * @opaque: user data to pass to @cb + * @freecb: callback to free @opaque + * + * Registers a callback to be invoked when the connection + * is closed. This callback is invoked when there is any + * condition that causes the socket connection to the + * hypervisor to be closed. + * + * The @freecb must not invoke any other libvirt public + * APIs, since it is not called from a re-entrant safe + * context. + * + * Returns 0 on success, -1 on error + */ +int virAdmConnectRegisterCloseCallback(virAdmConnectPtr conn, + virAdmConnectCloseFunc cb, + void *opaque, + virFreeCallback freecb) +{ + VIR_DEBUG("conn=%p", conn); + + virResetLastError(); + + virCheckAdmConnectReturn(conn, -1); + + virObjectRef(conn); + + virObjectLock(conn); + virObjectLock(conn->closeCallback); + + virCheckNonNullArgGoto(cb, error); + + if (conn->closeCallback->callback) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("A close callback is already registered")); + goto error; + } + + conn->closeCallback->conn = conn; + conn->closeCallback->callback = cb; + conn->closeCallback->opaque = opaque; + conn->closeCallback->freeCallback = freecb; + + virObjectUnlock(conn->closeCallback); + virObjectUnlock(conn); + + return 0; + + error: + virObjectUnlock(conn->closeCallback); + virObjectUnlock(conn); + virDispatchError(NULL); + virObjectUnref(conn); + return -1; + +} + +/** + * virAdmConnectUnregisterCloseCallback: + * @conn: pointer to connection object + * @cb: pointer to the current registered callback + * + * Unregisters the callback previously set with the + * virAdmConnectRegisterCloseCallback method. The callback + * will no longer receive notifications when the connection + * closes. If a virFreeCallback was provided at time of + * registration, it will be invoked. + * + * Returns 0 on success, -1 on error + */ +int virAdmConnectUnregisterCloseCallback(virAdmConnectPtr conn, + virAdmConnectCloseFunc cb) +{ + VIR_DEBUG("conn=%p", conn); + + virResetLastError(); + + virCheckAdmConnectReturn(conn, -1); + + virObjectLock(conn); + virObjectLock(conn->closeCallback); + + virCheckNonNullArgGoto(cb, error); + + if (conn->closeCallback->callback != cb) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("A different callback was requested")); + goto error; + } + + conn->closeCallback->callback = NULL; + if (conn->closeCallback->freeCallback) + conn->closeCallback->freeCallback(conn->closeCallback->opaque); + conn->closeCallback->freeCallback = NULL; + + virObjectUnlock(conn->closeCallback); + virObjectUnlock(conn); + virObjectUnref(conn); + + return 0; + + error: + virObjectUnlock(conn->closeCallback); + virObjectUnlock(conn); + virDispatchError(NULL); + return -1; +} diff --git a/src/libvirt_admin_public.syms b/src/libvirt_admin_public.syms index 16cfd42..5b9ba51 100644 --- a/src/libvirt_admin_public.syms +++ b/src/libvirt_admin_public.syms @@ -16,4 +16,6 @@ LIBVIRT_ADMIN_1.3.0 { virAdmConnectClose; virAdmConnectRef; virAdmConnectIsAlive; + virAdmConnectRegisterCloseCallback; + virAdmConnectUnregisterCloseCallback; }; diff --git a/tools/virt-admin.c b/tools/virt-admin.c index 4964e3d..679ae99 100644 --- a/tools/virt-admin.c +++ b/tools/virt-admin.c @@ -91,6 +91,10 @@ vshAdmConnect(vshControl *ctl, unsigned int flags) vshError(ctl, "%s", _("Failed to connect to the admin server")); return NULL; } else { + if (virAdmConnectRegisterCloseCallback(priv->conn, NULL, NULL, + NULL) < 0) + vshError(ctl, "%s", _("Unable to register disconnect callback")); +

if (priv->wantReconnect) vshPrint(ctl, "%s\n", _("Reconnected to the admin server")); else @@ -108,6 +112,7 @@ vshAdmDisconnectInternal(vshControl *ctl, virAdmConnectPtr *conn) if (!*conn) return ret; + virAdmConnectUnregisterCloseCallback(*conn, NULL); ret = virAdmConnectClose(*conn); if (ret < 0) vshError(ctl, "%s", _("Failed to disconnect from the admin server"));