Merge pull request #271 from savoirfairelinux/proxy_client_use_after_free

proxy client: retrieve search from callback

src/dht_proxy_client.cpp

@@ -350,7 +350,7 @@ DhtProxyClient::doPut(const InfoHash& key, Sp<Value> val, DoneCallback cb, time_
     o.thread = std::thread([=](){
         auto ok = std::make_shared<std::atomic_bool>(true);
         restbed::Http::async(req,
-            [this, ok](const std::shared_ptr<restbed::Request>& /*req*/,
+            [ok](const std::shared_ptr<restbed::Request>& /*req*/,
                         const std::shared_ptr<restbed::Response>& reply) {
             auto code = reply->get_status_code();
 
@@ -605,6 +605,12 @@ DhtProxyClient::doListen(const InfoHash& key, ValueCallback cb, Value::Filter fi
         return 0;
     }
 
+    struct State {
+        std::atomic_bool ok {true};
+        std::atomic_bool cancel {false};
+    };
+    auto state = std::make_shared<State>();
+
     auto token = ++listener_token_;
     auto l = search->second.listeners.find(token);
     if (l == search->second.listeners.end()) {
@@ -626,9 +632,18 @@ DhtProxyClient::doListen(const InfoHash& key, ValueCallback cb, Value::Filter fi
         }).first;
     }
 
-    ValueCache& cache = l->second.cache;
-    auto& job = l->second.cacheExpirationJob;
-    l->second.cb = [this,&cache,&job,key,token](const std::vector<Sp<Value>>& values, bool expired) {
+    l->second.cb = [this,key,token,state](const std::vector<Sp<Value>>& values, bool expired) {
+        if (state->cancel)
+            return false;
+        std::lock_guard<std::mutex> lock(searchLock_);
+        auto s = searches_.find(key);
+        if (s == searches_.end()) {
+            return false;
+        }
+        auto l = s->second.listeners.find(token);
+        if (l == s->second.listeners.end()) {
+            return false;
+        }
         const std::vector<Sp<Value>> new_values_empty;
         std::vector<Value::Id> expired_ids;
         if (expired) {
@@ -636,8 +651,8 @@ DhtProxyClient::doListen(const InfoHash& key, ValueCallback cb, Value::Filter fi
             for (const auto& v : values)
                 expired_ids.emplace_back(v->id);
         }
-        auto next = cache.onValues(expired ? new_values_empty : values, std::vector<Value::Id>{}, expired_ids, types, scheduler.time());
-        scheduler.edit(job, next);
+        auto next = l->second.cache.onValues(expired ? new_values_empty : values, std::vector<Value::Id>{}, expired_ids, types, scheduler.time());
+        scheduler.edit(l->second.cacheExpirationJob, next);
         return true;
     };
     std::weak_ptr<bool> isCanceledViaClose(l->second.isCanceledViaClose);
@@ -656,11 +671,6 @@ DhtProxyClient::doListen(const InfoHash& key, ValueCallback cb, Value::Filter fi
                 fillBodyToGetToken(req);
 #endif
 
-            struct State {
-                std::atomic_bool ok {true};
-                std::atomic_bool cancel {false};
-            };
-            auto state = std::make_shared<State>();
             restbed::Http::async(req,
                 [this, filter, vcb, pushNotifToken, state](const std::shared_ptr<restbed::Request>& req,
                                                                const std::shared_ptr<restbed::Response>& reply) {
@@ -928,7 +938,7 @@ DhtProxyClient::resubscribe(const InfoHash& key, Listener& listener)
         auto settings = std::make_shared<restbed::Settings>();
         auto ok = std::make_shared<std::atomic_bool>(true);
         restbed::Http::async(req,
-            [this, pushNotifToken, ok](const std::shared_ptr<restbed::Request>&,
+            [pushNotifToken, ok](const std::shared_ptr<restbed::Request>&,
                                        const std::shared_ptr<restbed::Response>& reply) {
             auto code = reply->get_status_code();
             if (code == 200) {