From: Jose Bollo Date: Mon, 20 Aug 2018 15:30:55 +0000 (+0200) Subject: afb-stub-ws: Safe handling of deconnections X-Git-Tag: flounder_5.99.4~2 X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?p=src%2Fapp-framework-binder.git;a=commitdiff_plain;h=7b6940f1524cac6172e71529a989424ff18fb850 afb-stub-ws: Safe handling of deconnections This commit also include many comments and improvements in naming of functions. Bug-AGL: SPEC-1668 Change-Id: I1b5dd95678d94e9edfca1c598c5697e90bb9e5bf Signed-off-by: Jose Bollo --- diff --git a/src/afb-evt.c b/src/afb-evt.c index ed3e4672..e06d06e1 100644 --- a/src/afb-evt.c +++ b/src/afb-evt.c @@ -537,7 +537,7 @@ void afb_evt_listener_unref(struct afb_evt_listener *listener) struct afb_evt_listener **prv; struct afb_evtid *evtid; - if (!__atomic_sub_fetch(&listener->refcount, 1, __ATOMIC_RELAXED)) { + if (listener && !__atomic_sub_fetch(&listener->refcount, 1, __ATOMIC_RELAXED)) { /* unlink the listener */ pthread_rwlock_wrlock(&listeners_rwlock); diff --git a/src/afb-proto-ws.c b/src/afb-proto-ws.c index 89d4522c..86112a32 100644 --- a/src/afb-proto-ws.c +++ b/src/afb-proto-ws.c @@ -1022,7 +1022,7 @@ struct afb_proto_ws *afb_proto_ws_create_server(struct fdev *fdev, const struct void afb_proto_ws_unref(struct afb_proto_ws *protows) { - if (!__atomic_sub_fetch(&protows->refcount, 1, __ATOMIC_RELAXED)) { + if (protows && !__atomic_sub_fetch(&protows->refcount, 1, __ATOMIC_RELAXED)) { afb_proto_ws_hangup(protows); afb_ws_destroy(protows->ws); pthread_mutex_destroy(&protows->mutex); diff --git a/src/afb-stub-ws.c b/src/afb-stub-ws.c index 5000f9f9..19b9b618 100644 --- a/src/afb-stub-ws.c +++ b/src/afb-stub-ws.c @@ -50,37 +50,37 @@ struct afb_stub_ws; -/* - * structure for a ws request +/** + * structure for a ws request: requests on server side */ struct server_req { - struct afb_xreq xreq; /* the xreq */ - struct afb_stub_ws *stubws; /* the client of the request */ - struct afb_proto_ws_call *call; /* the incoming call */ + struct afb_xreq xreq; /**< the xreq */ + struct afb_stub_ws *stubws; /**< the client of the request */ + struct afb_proto_ws_call *call; /**< the incoming call */ }; -/* +/** * structure for recording events on client side */ struct client_event { - struct client_event *next; - struct afb_event_x2 *event; - int id; - int refcount; + struct client_event *next; /**< link to the next */ + struct afb_event_x2 *event; /**< the local event */ + int id; /**< the identifier */ + int refcount; /**< a reference count */ }; -/* - * structure for recording describe requests +/** + * structure for recording describe requests on the client side */ struct client_describe { - struct afb_stub_ws *stubws; - struct jobloop *jobloop; - struct json_object *result; + struct afb_stub_ws *stubws; /**< the stub */ + struct jobloop *jobloop; /**< the jobloop to leave */ + struct json_object *result; /**< result */ }; -/* +/** * structure for jobs of describing */ struct server_describe @@ -89,7 +89,7 @@ struct server_describe struct afb_proto_ws_describe *describe; }; -/* +/** * structure for recording sessions */ struct server_session @@ -102,33 +102,41 @@ struct server_session struct afb_stub_ws { - /* count of references */ - int refcount; - - /* resource control */ - pthread_mutex_t mutex; - /* protocol */ struct afb_proto_ws *proto; - /* listener for events (server side) */ - struct afb_evt_listener *listener; - - /* event replica (client side) */ - struct client_event *events; - - /* credentials of the client (server side) */ - struct afb_cred *cred; - - /* sessions (server side) */ - struct server_session *sessions; - /* apiset */ struct afb_apiset *apiset; /* on hangup callback */ void (*on_hangup)(struct afb_stub_ws *); + union { + /* server side */ + struct { + /* listener for events */ + struct afb_evt_listener *listener; + + /* sessions */ + struct server_session *sessions; + + /* credentials of the client */ + struct afb_cred *cred; + }; + + /* client side */ + struct { + /* event replica */ + struct client_event *events; + }; + }; + + /* count of references */ + unsigned refcount; + + /* type of the stub: 0=server, 1=client */ + uint8_t is_client; + /* the api name */ char apiname[1]; }; @@ -195,6 +203,20 @@ static const struct afb_xreq_query_itf server_req_xreq_itf = { /******************* client part **********************************/ +/* destroy all events */ +static void client_drop_all_events(struct afb_stub_ws *stubws) +{ + struct client_event *ev, *nxt; + + nxt = __atomic_exchange_n(&stubws->events, NULL, __ATOMIC_RELAXED); + while (nxt) { + ev = nxt; + nxt = ev->next; + afb_evt_event_x2_unref(ev->event); + free(ev); + } +} + /* search the event */ static struct client_event *client_event_search(struct afb_stub_ws *stubws, uint32_t eventid, const char *name) { @@ -208,11 +230,16 @@ static struct client_event *client_event_search(struct afb_stub_ws *stubws, uint } /* on call, propagate it to the ws service */ -static void client_call_cb(void * closure, struct afb_xreq *xreq) +static void client_api_call_cb(void * closure, struct afb_xreq *xreq) { int rc; struct afb_stub_ws *stubws = closure; + if (stubws->proto == NULL) { + afb_xreq_reply(xreq, NULL, "disconnected", "server hung up"); + return; + } + rc = afb_proto_ws_client_call( stubws->proto, xreq->request.called_verb, @@ -238,7 +265,7 @@ static void client_send_describe_cb(int signum, void *closure, struct jobloop *j { struct client_describe *desc = closure; - if (signum) + if (signum || desc->stubws->proto == NULL) jobs_leave(jobloop); else { desc->jobloop = jobloop; @@ -247,7 +274,7 @@ static void client_send_describe_cb(int signum, void *closure, struct jobloop *j } /* get the description */ -static struct json_object *client_describe_cb(void * closure) +static struct json_object *client_api_describe_cb(void * closure) { struct client_describe desc; @@ -260,39 +287,43 @@ static struct json_object *client_describe_cb(void * closure) /******************* server part: manage events **********************************/ -static void server_event_add(void *closure, const char *event, int eventid) +static void server_event_add_cb(void *closure, const char *event, int eventid) { struct afb_stub_ws *stubws = closure; - afb_proto_ws_server_event_create(stubws->proto, event, eventid); + if (stubws->proto != NULL) + afb_proto_ws_server_event_create(stubws->proto, event, eventid); } -static void server_event_remove(void *closure, const char *event, int eventid) +static void server_event_remove_cb(void *closure, const char *event, int eventid) { struct afb_stub_ws *stubws = closure; - afb_proto_ws_server_event_remove(stubws->proto, event, eventid); + if (stubws->proto != NULL) + afb_proto_ws_server_event_remove(stubws->proto, event, eventid); } -static void server_event_push(void *closure, const char *event, int eventid, struct json_object *object) +static void server_event_push_cb(void *closure, const char *event, int eventid, struct json_object *object) { struct afb_stub_ws *stubws = closure; - afb_proto_ws_server_event_push(stubws->proto, event, eventid, object); + if (stubws->proto != NULL) + afb_proto_ws_server_event_push(stubws->proto, event, eventid, object); json_object_put(object); } -static void server_event_broadcast(void *closure, const char *event, int eventid, struct json_object *object) +static void server_event_broadcast_cb(void *closure, const char *event, int eventid, struct json_object *object) { struct afb_stub_ws *stubws = closure; - afb_proto_ws_server_event_broadcast(stubws->proto, event, object); + if (stubws->proto != NULL) + afb_proto_ws_server_event_broadcast(stubws->proto, event, object); json_object_put(object); } /*****************************************************/ -static void on_reply(void *closure, void *request, struct json_object *object, const char *error, const char *info) +static void client_on_reply_cb(void *closure, void *request, struct json_object *object, const char *error, const char *info) { struct afb_xreq *xreq = request; @@ -300,7 +331,7 @@ static void on_reply(void *closure, void *request, struct json_object *object, c afb_xreq_unhooked_unref(xreq); } -static void on_event_create(void *closure, const char *event_name, int event_id) +static void client_on_event_create_cb(void *closure, const char *event_name, int event_id) { struct afb_stub_ws *stubws = closure; struct client_event *ev; @@ -308,7 +339,7 @@ static void on_event_create(void *closure, const char *event_name, int event_id) /* check conflicts */ ev = client_event_search(stubws, event_id, event_name); if (ev != NULL) { - ev->refcount++; + __atomic_add_fetch(&ev->refcount, 1, __ATOMIC_RELAXED); return; } @@ -328,7 +359,7 @@ static void on_event_create(void *closure, const char *event_name, int event_id) ERROR("can't create event %s, out of memory", event_name); } -static void on_event_remove(void *closure, const char *event_name, int event_id) +static void client_on_event_remove_cb(void *closure, const char *event_name, int event_id) { struct afb_stub_ws *stubws = closure; struct client_event *ev, **prv; @@ -339,7 +370,8 @@ static void on_event_remove(void *closure, const char *event_name, int event_id) return; /* decrease the reference count */ - if (--ev->refcount) + + if (__atomic_sub_fetch(&ev->refcount, 1, __ATOMIC_RELAXED)) return; /* unlinks the event */ @@ -353,7 +385,7 @@ static void on_event_remove(void *closure, const char *event_name, int event_id) free(ev); } -static void on_event_subscribe(void *closure, void *request, const char *event_name, int event_id) +static void client_on_event_subscribe_cb(void *closure, void *request, const char *event_name, int event_id) { struct afb_stub_ws *stubws = closure; struct afb_xreq *xreq = request; @@ -368,7 +400,7 @@ static void on_event_subscribe(void *closure, void *request, const char *event_n ERROR("can't subscribe: %m"); } -static void on_event_unsubscribe(void *closure, void *request, const char *event_name, int event_id) +static void client_on_event_unsubscribe_cb(void *closure, void *request, const char *event_name, int event_id) { struct afb_stub_ws *stubws = closure; struct afb_xreq *xreq = request; @@ -383,7 +415,7 @@ static void on_event_unsubscribe(void *closure, void *request, const char *event ERROR("can't unsubscribe: %m"); } -static void on_event_push(void *closure, const char *event_name, int event_id, struct json_object *data) +static void client_on_event_push_cb(void *closure, const char *event_name, int event_id, struct json_object *data) { struct afb_stub_ws *stubws = closure; struct client_event *ev; @@ -396,14 +428,14 @@ static void on_event_push(void *closure, const char *event_name, int event_id, s ERROR("unreadable push event"); } -static void on_event_broadcast(void *closure, const char *event_name, struct json_object *data) +static void client_on_event_broadcast_cb(void *closure, const char *event_name, struct json_object *data) { afb_evt_broadcast(event_name, data); } /*****************************************************/ -static void record_session(struct afb_stub_ws *stubws, struct afb_session *session) +static void server_record_session(struct afb_stub_ws *stubws, struct afb_session *session) { struct server_session *s, **prv; @@ -430,22 +462,22 @@ static void record_session(struct afb_stub_ws *stubws, struct afb_session *sessi } } -static void release_all_sessions(struct afb_stub_ws *stubws) +static void server_release_all_sessions(struct afb_stub_ws *stubws) { - struct server_session *s, *n; + struct server_session *ses, *nses; - s = __atomic_exchange_n(&stubws->sessions, NULL, __ATOMIC_RELAXED); - while(s) { - n = s->next; - afb_session_unref(s->session); - free(s); - s = n; + nses = __atomic_exchange_n(&stubws->sessions, NULL, __ATOMIC_RELAXED); + while(nses) { + ses = nses; + nses = ses->next; + afb_session_unref(ses->session); + free(ses); } } /*****************************************************/ -static void on_call(void *closure, struct afb_proto_ws_call *call, const char *verb, struct json_object *args, const char *sessionid, const char *user_creds) +static void server_on_call_cb(void *closure, struct afb_proto_ws_call *call, const char *verb, struct json_object *args, const char *sessionid, const char *user_creds) { struct afb_stub_ws *stubws = closure; struct server_req *wreq; @@ -465,7 +497,7 @@ static void on_call(void *closure, struct afb_proto_ws_call *call, const char *v if (afb_context_connect(&wreq->xreq.context, sessionid, NULL) < 0) goto unconnected; wreq->xreq.context.validated = 1; - record_session(stubws, wreq->xreq.context.session); + server_record_session(stubws, wreq->xreq.context.session); if (wreq->xreq.context.created) afb_session_set_autoclose(wreq->xreq.context.session, 1); @@ -486,7 +518,7 @@ out_of_memory: afb_proto_ws_call_unref(call); } -static void server_describe_sjob(int signum, void *closure) +static void server_describe_cb(int signum, void *closure) { struct json_object *obj; struct server_describe *desc = closure; @@ -502,11 +534,11 @@ static void server_describe_sjob(int signum, void *closure) static void server_describe_job(int signum, void *closure) { - server_describe_sjob(signum, closure); + server_describe_cb(signum, closure); free(closure); } -static void on_describe(void *closure, struct afb_proto_ws_describe *describe) +static void server_on_describe_cb(void *closure, struct afb_proto_ws_describe *describe) { struct server_describe *desc, sdesc; struct afb_stub_ws *stubws = closure; @@ -520,74 +552,70 @@ static void on_describe(void *closure, struct afb_proto_ws_describe *describe) afb_stub_ws_addref(stubws); /* process */ - if (desc == &sdesc) - jobs_call(NULL, 0, server_describe_sjob, desc); - else { - if (jobs_queue(NULL, 0, server_describe_job, desc) < 0) - jobs_call(NULL, 0, server_describe_job, desc); - } + if (desc == &sdesc || jobs_queue(NULL, 0, server_describe_job, desc) < 0) + jobs_call(NULL, 0, server_describe_cb, desc); } /*****************************************************/ static const struct afb_proto_ws_client_itf client_itf = { - .on_reply = on_reply, - .on_event_create = on_event_create, - .on_event_remove = on_event_remove, - .on_event_subscribe = on_event_subscribe, - .on_event_unsubscribe = on_event_unsubscribe, - .on_event_push = on_event_push, - .on_event_broadcast = on_event_broadcast, + .on_reply = client_on_reply_cb, + .on_event_create = client_on_event_create_cb, + .on_event_remove = client_on_event_remove_cb, + .on_event_subscribe = client_on_event_subscribe_cb, + .on_event_unsubscribe = client_on_event_unsubscribe_cb, + .on_event_push = client_on_event_push_cb, + .on_event_broadcast = client_on_event_broadcast_cb, }; -static const struct afb_proto_ws_server_itf server_itf = -{ - .on_call = on_call, - .on_describe = on_describe +static struct afb_api_itf client_api_itf = { + .call = client_api_call_cb, + .describe = client_api_describe_cb }; -static struct afb_api_itf ws_api_itf = { - .call = client_call_cb, - .describe = client_describe_cb +static const struct afb_proto_ws_server_itf server_itf = +{ + .on_call = server_on_call_cb, + .on_describe = server_on_describe_cb }; /* the interface for events pushing */ -static const struct afb_evt_itf server_evt_itf = { - .broadcast = server_event_broadcast, - .push = server_event_push, - .add = server_event_add, - .remove = server_event_remove +static const struct afb_evt_itf server_event_itf = { + .broadcast = server_event_broadcast_cb, + .push = server_event_push_cb, + .add = server_event_add_cb, + .remove = server_event_remove_cb }; /*****************************************************/ -static void drop_all_events(struct afb_stub_ws *stubws) +/* disconnect */ +static void disconnect(struct afb_stub_ws *stubws) { - struct client_event *ev, *nxt; - - ev = stubws->events; - stubws->events = NULL; - - while (ev) { - nxt = ev->next; - afb_evt_event_x2_unref(ev->event); - free(ev); - ev = nxt; + afb_proto_ws_unref(__atomic_exchange_n(&stubws->proto, NULL, __ATOMIC_RELAXED)); + if (stubws->is_client) + client_drop_all_events(stubws); + else { + afb_evt_listener_unref(__atomic_exchange_n(&stubws->listener, NULL, __ATOMIC_RELAXED)); + afb_cred_unref(__atomic_exchange_n(&stubws->cred, NULL, __ATOMIC_RELAXED)); + server_release_all_sessions(stubws); } } + /* callback when receiving a hangup */ static void on_hangup(void *closure) { struct afb_stub_ws *stubws = closure; - afb_stub_ws_addref(stubws); - if (stubws->on_hangup) - stubws->on_hangup(stubws); - - release_all_sessions(stubws); - afb_stub_ws_unref(stubws); + if (stubws->proto) { + afb_stub_ws_addref(stubws); + disconnect(stubws); + if (stubws->on_hangup) + stubws->on_hangup(stubws); + afb_stub_ws_unref(stubws); + } } static int enqueue_processing(void (*callback)(int signum, void* arg), void *arg) @@ -597,7 +625,22 @@ static int enqueue_processing(void (*callback)(int signum, void* arg), void *arg /*****************************************************/ -static struct afb_stub_ws *afb_stub_ws_create(struct fdev *fdev, const char *apiname, struct afb_apiset *apiset, int client) +static struct afb_proto_ws *afb_stub_ws_create_proto(struct afb_stub_ws *stubws, struct fdev *fdev, uint8_t is_client) +{ + struct afb_proto_ws *proto; + + stubws->proto = proto = is_client + ? afb_proto_ws_create_client(fdev, &client_itf, stubws) + : afb_proto_ws_create_server(fdev, &server_itf, stubws); + if (proto) { + afb_proto_ws_on_hangup(proto, on_hangup); + afb_proto_ws_set_queuing(proto, enqueue_processing); + } + + return proto; +} + +static struct afb_stub_ws *afb_stub_ws_create(struct fdev *fdev, const char *apiname, struct afb_apiset *apiset, uint8_t is_client) { struct afb_stub_ws *stubws; @@ -605,17 +648,11 @@ static struct afb_stub_ws *afb_stub_ws_create(struct fdev *fdev, const char *api if (stubws == NULL) errno = ENOMEM; else { - if (client) - stubws->proto = afb_proto_ws_create_client(fdev, &client_itf, stubws); - else - stubws->proto = afb_proto_ws_create_server(fdev, &server_itf, stubws); - - if (stubws->proto) { + if (afb_stub_ws_create_proto(stubws, fdev, is_client)) { + stubws->refcount = 1; + stubws->is_client = is_client; strcpy(stubws->apiname, apiname); stubws->apiset = afb_apiset_addref(apiset); - stubws->refcount = 1; - afb_proto_ws_on_hangup(stubws->proto, on_hangup); - afb_proto_ws_set_queuing(stubws->proto, enqueue_processing); return stubws; } free(stubws); @@ -636,7 +673,7 @@ struct afb_stub_ws *afb_stub_ws_create_server(struct fdev *fdev, const char *api stubws = afb_stub_ws_create(fdev, apiname, apiset, 0); if (stubws) { stubws->cred = afb_cred_create_for_socket(fdev_fd(fdev)); - stubws->listener = afb_evt_listener_create(&server_evt_itf, stubws); + stubws->listener = afb_evt_listener_create(&server_event_itf, stubws); if (stubws->listener != NULL) return stubws; afb_stub_ws_unref(stubws); @@ -646,13 +683,9 @@ struct afb_stub_ws *afb_stub_ws_create_server(struct fdev *fdev, const char *api void afb_stub_ws_unref(struct afb_stub_ws *stubws) { - if (!__atomic_sub_fetch(&stubws->refcount, 1, __ATOMIC_RELAXED)) { - drop_all_events(stubws); - if (stubws->listener) - afb_evt_listener_unref(stubws->listener); - release_all_sessions(stubws); - afb_proto_ws_unref(stubws->proto); - afb_cred_unref(stubws->cred); + if (stubws && !__atomic_sub_fetch(&stubws->refcount, 1, __ATOMIC_RELAXED)) { + + disconnect(stubws); afb_apiset_unref(stubws->apiset); free(stubws); } @@ -677,9 +710,9 @@ struct afb_api_item afb_stub_ws_client_api(struct afb_stub_ws *stubws) { struct afb_api_item api; - assert(!stubws->listener); /* check client */ + assert(stubws->is_client); /* check client */ api.closure = stubws; - api.itf = &ws_api_itf; + api.itf = &client_api_itf; api.group = NULL; return api; } @@ -688,4 +721,3 @@ int afb_stub_ws_client_add(struct afb_stub_ws *stubws, struct afb_apiset *apiset { return afb_apiset_add(apiset, stubws->apiname, afb_stub_ws_client_api(stubws)); } -