afb-xreq: Detection of self locks due to 'noconcurrency'

Change-Id: I112526f315d861ebb6d0d12edea06372f902db2c
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

diff --git a/src/afb-xreq.c b/src/afb-xreq.c
index de0710d..ea830d9 100644 (file)
--- a/src/afb-xreq.c
+++ b/src/afb-xreq.c
@@ -52,6 +52,8 @@ static inline void xreq_unref(struct afb_xreq *xreq)
                        afb_xreq_fail(xreq, "error", "no reply");
                if (xreq->hookflags)
                        afb_hook_xreq_end(xreq);
+               if (xreq->caller)
+                       xreq_unref(xreq->caller);
                xreq->queryitf->unref(xreq);
        }
 }
@@ -71,7 +73,6 @@ static inline struct afb_req to_req(struct afb_xreq *xreq)
 struct subcall
 {
        struct afb_xreq xreq;
-       struct afb_xreq *caller;
 
        void (*completion)(struct subcall*, int, struct json_object*);
 
@@ -95,14 +96,14 @@ static int subcall_subscribe_cb(struct afb_xreq *xreq, struct afb_event event)
 {
        struct subcall *subcall = CONTAINER_OF_XREQ(struct subcall, xreq);
 
-       return afb_xreq_subscribe(subcall->caller, event);
+       return afb_xreq_subscribe(subcall->xreq.caller, event);
 }
 
 static int subcall_unsubscribe_cb(struct afb_xreq *xreq, struct afb_event event)
 {
        struct subcall *subcall = CONTAINER_OF_XREQ(struct subcall, xreq);
 
-       return afb_xreq_unsubscribe(subcall->caller, event);
+       return afb_xreq_unsubscribe(subcall->xreq.caller, event);
 }
 
 static void subcall_reply_cb(struct afb_xreq *xreq, int status, struct json_object *result)
@@ -120,7 +121,6 @@ static void subcall_destroy_cb(struct afb_xreq *xreq)
 
        json_object_put(subcall->xreq.json);
        afb_cred_unref(subcall->xreq.cred);
-       xreq_unref(subcall->caller);
        free(subcall);
 }
 
@@ -161,7 +161,7 @@ static struct subcall *subcall_alloc(
                subcall->xreq.json = args;
                subcall->xreq.api = api;
                subcall->xreq.verb = verb;
-               subcall->caller = caller;
+               subcall->xreq.caller = caller;
                xreq_addref(caller);
        }
        return subcall;
@@ -175,18 +175,18 @@ static void subcall_on_reply(struct subcall *subcall, int status, struct json_ob
 
 static void subcall_req_on_reply(struct subcall *subcall, int status, struct json_object *result)
 {
-       subcall->callback2(subcall->closure, status, result, to_req(subcall->caller));
+       subcall->callback2(subcall->closure, status, result, to_req(subcall->xreq.caller));
 }
 
 static void subcall_hooked_on_reply(struct subcall *subcall, int status, struct json_object *result)
 {
-       afb_hook_xreq_subcall_result(subcall->caller, status, result);
+       afb_hook_xreq_subcall_result(subcall->xreq.caller, status, result);
        subcall_on_reply(subcall, status, result);
 }
 
 static void subcall_req_hooked_on_reply(struct subcall *subcall, int status, struct json_object *result)
 {
-       afb_hook_xreq_subcall_req_result(subcall->caller, status, result);
+       afb_hook_xreq_subcall_req_result(subcall->xreq.caller, status, result);
        subcall_req_on_reply(subcall, status, result);
 }
 
@@ -206,13 +206,13 @@ static void subcall_reply_direct_cb(void *closure, int status, struct json_objec
 static void subcall_process(struct subcall *subcall, void (*completion)(struct subcall*, int, struct json_object*))
 {
        subcall->completion = completion;
-       if (subcall->caller->queryitf->subcall) {
-               subcall->caller->queryitf->subcall(
-                       subcall->caller, subcall->xreq.api, subcall->xreq.verb,
+       if (subcall->xreq.caller->queryitf->subcall) {
+               subcall->xreq.caller->queryitf->subcall(
+                       subcall->xreq.caller, subcall->xreq.api, subcall->xreq.verb,
                        subcall->xreq.json, subcall_reply_direct_cb, &subcall->xreq);
        } else {
                afb_xreq_addref(&subcall->xreq);
-               afb_xreq_process(&subcall->xreq, subcall->caller->apiset);
+               afb_xreq_process(&subcall->xreq, subcall->xreq.caller->apiset);
        }
 }
 
@@ -982,19 +982,37 @@ static void process_async(int signum, void *arg)
 
 void afb_xreq_process(struct afb_xreq *xreq, struct afb_apiset *apiset)
 {
+       const void *jobkey;
        const struct afb_api *api;
+       struct afb_xreq *caller;
 
        xreq->apiset = apiset;
        api = afb_apiset_lookup_started(apiset, xreq->api, 1);
-       xreq->context.api_key = (void*)api;
+       xreq->context.api_key = api;
 
+       if (!api || !api->noconcurrency)
+               jobkey = NULL;
+       else {
+               caller = xreq->caller;
+               while (caller) {
+                       if (caller->context.api_key == api) {
+                               /* noconcurrency lock detected */
+                               ERROR("self-lock detected in call stack for API %s", xreq->api);
+                               afb_xreq_fail_f(xreq, "cancelled", "recursive self lock, API %s", xreq->api);
+                               goto end;
+                       }
+                       caller = caller->caller;
+               }
+               jobkey = api;
+       }
        xreq_addref(xreq);
-       if (jobs_queue(api && api->noconcurrency ? (void*)api : NULL, afb_apiset_timeout_get(apiset), process_async, xreq) < 0) {
+       if (jobs_queue(jobkey, afb_apiset_timeout_get(apiset), process_async, xreq) < 0) {
                /* TODO: allows or not to proccess it directly as when no threading? (see above) */
                ERROR("can't process job with threads: %m");
                afb_xreq_fail_f(xreq, "cancelled", "not able to create a job for the task");
                xreq_unref(xreq);
        }
+end:
        xreq_unref(xreq);
 }
 

diff --git a/src/afb-xreq.h b/src/afb-xreq.h
index 77f843f..ae71147 100644 (file)
--- a/src/afb-xreq.h
+++ b/src/afb-xreq.h
@@ -65,6 +65,7 @@ struct afb_xreq
        int hookindex;                  /**< index for hooking */
        struct afb_evt_listener *listener; /**< event listener for the request */
        struct afb_cred *cred;          /**< client credential if revelant */
+       struct afb_xreq *caller;        /**< caller request if any */
 };
 
 /**