1 /* 2 * 3 * Copyright 2017 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 #ifndef GRPC_CORE_LIB_GPRPP_FORK_H 20 #define GRPC_CORE_LIB_GPRPP_FORK_H 21 22 /* 23 * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK 24 * AROUND VERY SPECIFIC USE CASES. 25 */ 26 27 namespace grpc_core { 28 29 namespace internal { 30 class ExecCtxState; 31 class ThreadState; 32 } // namespace internal 33 34 class Fork { 35 public: 36 typedef void (*child_postfork_func)(void); 37 38 static void GlobalInit(); 39 static void GlobalShutdown(); 40 41 // Returns true if fork suppport is enabled, false otherwise 42 static bool Enabled(); 43 44 // Increment the count of active ExecCtxs. 45 // Will block until a pending fork is complete if one is in progress. 46 static void IncExecCtxCount(); 47 48 // Decrement the count of active ExecCtxs 49 static void DecExecCtxCount(); 50 51 // Provide a function that will be invoked in the child's postfork handler to 52 // reset the polling engine's internal state. 53 static void SetResetChildPollingEngineFunc( 54 child_postfork_func reset_child_polling_engine); 55 static child_postfork_func GetResetChildPollingEngineFunc(); 56 57 // Check if there is a single active ExecCtx 58 // (the one used to invoke this function). If there are more, 59 // return false. Otherwise, return true and block creation of 60 // more ExecCtx s until AlloWExecCtx() is called 61 // 62 static bool BlockExecCtx(); 63 static void AllowExecCtx(); 64 65 // Increment the count of active threads. 66 static void IncThreadCount(); 67 68 // Decrement the count of active threads. 69 static void DecThreadCount(); 70 71 // Await all core threads to be joined. 72 static void AwaitThreads(); 73 74 // Test only: overrides environment variables/compile flags 75 // Must be called before grpc_init() 76 static void Enable(bool enable); 77 78 private: 79 static internal::ExecCtxState* exec_ctx_state_; 80 static internal::ThreadState* thread_state_; 81 static bool support_enabled_; 82 static bool override_enabled_; 83 static child_postfork_func reset_child_polling_engine_; 84 }; 85 86 } // namespace grpc_core 87 88 #endif /* GRPC_CORE_LIB_GPRPP_FORK_H */ 89
