From: Rafal Walczyna <r.walczyna@samsung.com>
Date: Tue, 25 Aug 2020 07:29:53 +0000 (+0200)
Subject: [MediaController] Add locks for variable used in different threads
X-Git-Tag: accepted/tizen/5.5/unified/20201103.003327~3^2^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=099689384c7ac05b782accc6c82c7edca052b8ff;p=platform%2Fcore%2Fapi%2Fwebapi-plugins.git

[MediaController] Add locks for variable used in different threads

Handles for client and server can be used in different threads.
It may cause segmentation fault when already freed handle will be used.

Verification: Build successful

Change-Id: Iba90d1a85be51710ccda169389ce393f5ce1d1a3
Signed-off-by: Rafal Walczyna <r.walczyna@samsung.com>
---

diff --git a/src/mediacontroller/mediacontroller_client.cc b/src/mediacontroller/mediacontroller_client.cc
index cce90a2..429f141 100644
--- a/src/mediacontroller/mediacontroller_client.cc
+++ b/src/mediacontroller/mediacontroller_client.cc
@@ -46,8 +46,12 @@ MediaControllerClient::~MediaControllerClient() {
     LoggerE("Failed to unset playback info listener");
   }
 
-  if (nullptr != handle_ && MEDIA_CONTROLLER_ERROR_NONE != mc_client_destroy(handle_)) {
-    LoggerE("Unable to destroy media controller client");
+  {
+    std::lock_guard<std::mutex> lock(handle_mutex_);
+    if (nullptr != handle_ && MEDIA_CONTROLLER_ERROR_NONE != mc_client_destroy(handle_)) {
+      LoggerE("Unable to destroy media controller client");
+    }
+    handle_ = nullptr;
   }
 }
 
@@ -66,8 +70,10 @@ PlatformResult MediaControllerClient::Init() {
 PlatformResult MediaControllerClient::FindServers(picojson::array* servers) {
   ScopeLogger();
   int ret;
-
-  ret = mc_client_foreach_server(handle_, FindServersCallback, servers);
+  {
+    std::lock_guard<std::mutex> lock(handle_mutex_);
+    ret = mc_client_foreach_server(handle_, FindServersCallback, servers);
+  }
   if (MEDIA_CONTROLLER_ERROR_NONE != ret) {
     return LogAndCreateResult(
         ErrorCode::UNKNOWN_ERR, "Unable to fetch active servers, error",
@@ -125,7 +131,10 @@ PlatformResult MediaControllerClient::GetLatestServerInfo(picojson::value* serve
     free(name);
   };
   mc_server_state_e state;
-  ret = mc_client_get_latest_server_info(handle_, &name, &state);
+  {
+    std::lock_guard<std::mutex> lock(handle_mutex_);
+    ret = mc_client_get_latest_server_info(handle_, &name, &state);
+  }
   if (MEDIA_CONTROLLER_ERROR_NONE != ret) {
     return LogAndCreateResult(
         ErrorCode::UNKNOWN_ERR, "Error getting latest server info",
@@ -547,6 +556,7 @@ PlatformResult MediaControllerClient::SendPlaybackState(const std::string& serve
   }
 
   int ret;
+  std::lock_guard<std::mutex> lock(handle_mutex_);
   ret = mc_client_send_playback_state_command(handle_, server_name.c_str(),
                                               static_cast<mc_playback_states_e>(state_e));
   if (MEDIA_CONTROLLER_ERROR_NONE != ret) {
@@ -566,6 +576,7 @@ PlatformResult MediaControllerClient::SendPlaybackPosition(const std::string& se
   SCOPE_EXIT {
     free(request_id);
   };*/
+  std::lock_guard<std::mutex> lock(handle_mutex_);
   int ret = mc_client_send_playback_position_cmd(handle_, server_name.c_str(),
                                                  static_cast<unsigned long long>(position),
                                                  /*&request_id*/ nullptr);
@@ -585,6 +596,7 @@ PlatformResult MediaControllerClient::SendShuffleMode(const std::string& server_
   SCOPE_EXIT {
     free(request_id);
   };*/
+  std::lock_guard<std::mutex> lock(handle_mutex_);
   int ret = mc_client_send_shuffle_mode_cmd(handle_, server_name.c_str(),
                                             mode ? MC_SHUFFLE_MODE_ON : MC_SHUFFLE_MODE_OFF,
                                             /*&request_id*/ nullptr);
diff --git a/src/mediacontroller/mediacontroller_client.h b/src/mediacontroller/mediacontroller_client.h
index bb7cb8a..f1aa8c4 100644
--- a/src/mediacontroller/mediacontroller_client.h
+++ b/src/mediacontroller/mediacontroller_client.h
@@ -18,6 +18,7 @@
 #define MEDIACONTROLLER_MEDIACONTROLLER_CLIENT_H_
 
 #include <media_controller_client.h>
+#include <mutex>
 #include <string>
 
 #include "common/platform_result.h"
@@ -58,6 +59,11 @@ class MediaControllerClient {
  private:
   mc_client_h handle_;
 
+  // This mutex is used to guard handle_ usage in TaskQueue
+  // and its destruction, but there is no need to
+  // guard every call on main thread.
+  std::mutex handle_mutex_;
+
   JsonCallback playback_info_listener_;
   JsonCallback server_status_listener_;
   JsonCallback command_reply_callback_;
diff --git a/src/mediacontroller/mediacontroller_server.cc b/src/mediacontroller/mediacontroller_server.cc
index b2a3e83..86204fb 100644
--- a/src/mediacontroller/mediacontroller_server.cc
+++ b/src/mediacontroller/mediacontroller_server.cc
@@ -56,6 +56,7 @@ MediaControllerServer::~MediaControllerServer() {
   if (nullptr != handle_ && MEDIA_CONTROLLER_ERROR_NONE != mc_server_destroy(handle_)) {
     LoggerE("Unable to destroy media controller server");
   }
+  handle_ = nullptr;
 }
 
 PlatformResult MediaControllerServer::Init() {