From 38ab21ee0996a54c682488bcf43ecf5ba0f7f24a Mon Sep 17 00:00:00 2001
From: kpayson64 <kpayson@google.com>
Date: Thu, 8 Mar 2018 15:47:40 -0800
Subject: [PATCH 1/6] Add exec_ctx check to fork handlers

---
 CMakeLists.txt                                |  30 +++
 Makefile                                      |  36 ++++
 build.yaml                                    |  12 ++
 src/core/lib/gpr/fork.cc                      | 185 ++++++++++++++++--
 src/core/lib/gpr/fork.h                       |  57 +++++-
 src/core/lib/gprpp/thd.h                      |   3 -
 src/core/lib/gprpp/thd_posix.cc               |  55 +-----
 src/core/lib/gprpp/thd_windows.cc             |   7 -
 src/core/lib/iomgr/exec_ctx.h                 |  12 +-
 src/core/lib/iomgr/fork_posix.cc              |  44 +++--
 src/core/lib/surface/init.cc                  |   6 +-
 test/core/gpr/BUILD                           |  10 +
 test/core/gpr/fork_test.cc                    | 136 +++++++++++++
 .../generated/sources_and_headers.json        |  15 ++
 tools/run_tests/generated/tests.json          |  20 ++
 15 files changed, 528 insertions(+), 100 deletions(-)
 create mode 100644 test/core/gpr/fork_test.cc

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5dfbdcb85a0..aa4dbb4f9b3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -263,6 +263,9 @@ endif()
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_c fling_test)
 endif()
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC)
+add_dependencies(buildtests_c fork_test)
+endif()
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_c goaway_server_test)
 endif()
@@ -6152,6 +6155,33 @@ target_link_libraries(fling_test
   gpr
 )
 
+endif()
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC)
+
+add_executable(fork_test
+  test/core/gpr/fork_test.cc
+)
+
+
+target_include_directories(fork_test
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${_gRPC_SSL_INCLUDE_DIR}
+  PRIVATE ${_gRPC_PROTOBUF_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ZLIB_INCLUDE_DIR}
+  PRIVATE ${_gRPC_BENCHMARK_INCLUDE_DIR}
+  PRIVATE ${_gRPC_CARES_INCLUDE_DIR}
+  PRIVATE ${_gRPC_GFLAGS_INCLUDE_DIR}
+)
+
+target_link_libraries(fork_test
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  gpr_test_util
+  gpr
+)
+
 endif()
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
diff --git a/Makefile b/Makefile
index 7bc2c829385..631ecf9f96e 100644
--- a/Makefile
+++ b/Makefile
@@ -988,6 +988,7 @@ fling_client: $(BINDIR)/$(CONFIG)/fling_client
 fling_server: $(BINDIR)/$(CONFIG)/fling_server
 fling_stream_test: $(BINDIR)/$(CONFIG)/fling_stream_test
 fling_test: $(BINDIR)/$(CONFIG)/fling_test
+fork_test: $(BINDIR)/$(CONFIG)/fork_test
 goaway_server_test: $(BINDIR)/$(CONFIG)/goaway_server_test
 gpr_cpu_test: $(BINDIR)/$(CONFIG)/gpr_cpu_test
 gpr_env_test: $(BINDIR)/$(CONFIG)/gpr_env_test
@@ -1423,6 +1424,7 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/fling_server \
   $(BINDIR)/$(CONFIG)/fling_stream_test \
   $(BINDIR)/$(CONFIG)/fling_test \
+  $(BINDIR)/$(CONFIG)/fork_test \
   $(BINDIR)/$(CONFIG)/goaway_server_test \
   $(BINDIR)/$(CONFIG)/gpr_cpu_test \
   $(BINDIR)/$(CONFIG)/gpr_env_test \
@@ -1929,6 +1931,8 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/fling_stream_test || ( echo test fling_stream_test failed ; exit 1 )
 	$(E) "[RUN]     Testing fling_test"
 	$(Q) $(BINDIR)/$(CONFIG)/fling_test || ( echo test fling_test failed ; exit 1 )
+	$(E) "[RUN]     Testing fork_test"
+	$(Q) $(BINDIR)/$(CONFIG)/fork_test || ( echo test fork_test failed ; exit 1 )
 	$(E) "[RUN]     Testing goaway_server_test"
 	$(Q) $(BINDIR)/$(CONFIG)/goaway_server_test || ( echo test goaway_server_test failed ; exit 1 )
 	$(E) "[RUN]     Testing gpr_cpu_test"
@@ -10954,6 +10958,38 @@ endif
 endif
 
 
+FORK_TEST_SRC = \
+    test/core/gpr/fork_test.cc \
+
+FORK_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(FORK_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/fork_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/fork_test: $(FORK_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(FORK_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/fork_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/gpr/fork_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_fork_test: $(FORK_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(FORK_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 GOAWAY_SERVER_TEST_SRC = \
     test/core/end2end/goaway_server_test.cc \
 
diff --git a/build.yaml b/build.yaml
index e2bb8bfa9ff..0d8846bcd1c 100644
--- a/build.yaml
+++ b/build.yaml
@@ -2316,6 +2316,18 @@ targets:
   - mac
   - linux
   - posix
+- name: fork_test
+  build: test
+  language: c
+  src:
+  - test/core/gpr/fork_test.cc
+  deps:
+  - gpr_test_util
+  - gpr
+  platforms:
+  - mac
+  - linux
+  uses_polling: false
 - name: goaway_server_test
   cpu_cost: 0.1
   build: test
diff --git a/src/core/lib/gpr/fork.cc b/src/core/lib/gpr/fork.cc
index 812522b058a..ec25848bd02 100644
--- a/src/core/lib/gpr/fork.cc
+++ b/src/core/lib/gpr/fork.cc
@@ -23,6 +23,8 @@
 #include <string.h>
 
 #include <grpc/support/alloc.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/time.h>
 
 #include "src/core/lib/gpr/env.h"
 #include "src/core/lib/gpr/useful.h"
@@ -32,14 +34,120 @@
  *       AROUND VERY SPECIFIC USE CASES.
  */
 
-static int override_fork_support_enabled = -1;
-static int fork_support_enabled;
+// The exec_ctx_count has 2 modes, blocked and unblocked.
+// When unblocked, the count is 2-indexed; exec_ctx_count=2 indicates
+// 0 active ExecCtxs, exex_ctx_count=3 indicates 1 active ExecCtxs...
 
-void grpc_fork_support_init() {
+// When blocked, the exec_ctx_count is 0-indexed.  Note that ExecCtx
+// creation can only be blocked if there is exactly 1 outstanding ExecCtx,
+// meaning that BLOCKED and UNBLOCKED counts partition the integers
+#define UNBLOCKED(n) (n + 2)
+#define BLOCKED(n) (n)
+
+class ExecCtxState {
+  public:
+    ExecCtxState() : fork_complete_(true) {
+      gpr_mu_init(&mu_);
+      gpr_cv_init(&cv_);
+      gpr_atm_no_barrier_store(&count_, UNBLOCKED(0));
+    }
+
+  void IncExecCtxCount() {
+    intptr_t count = static_cast<intptr_t>(
+        gpr_atm_no_barrier_load(&count_));
+    while (true) {
+      if (count <= BLOCKED(1)) {
+        // This only occurs if we are trying to fork.  Wait until the fork()
+        // operation completes before allowing new ExecCtxs.
+        gpr_mu_lock(&mu_);
+        if (gpr_atm_no_barrier_load(&count_) <= BLOCKED(1)) {
+          while (!fork_complete_) {
+            gpr_cv_wait(&cv_, &mu_,
+                        gpr_inf_future(GPR_CLOCK_REALTIME));
+          }
+        }
+        gpr_mu_unlock(&mu_);
+      } else if (gpr_atm_no_barrier_cas(&count_, count,
+                                        count + 1)) {
+        break;
+      }
+      count = gpr_atm_no_barrier_load(&count_);
+    }
+  }
+
+  void DecExecCtxCount() {
+    gpr_atm_no_barrier_fetch_add(&count_, -1);
+  }
+
+  bool BlockExecCtx() {
+    // Assumes there is an active ExecCtx when this function is called
+    if (gpr_atm_no_barrier_cas(&count_, UNBLOCKED(1),
+                               BLOCKED(1))) {
+      fork_complete_ = false;
+      return true;
+    }
+    return false;
+  }
+
+  void AllowExecCtx() {
+    gpr_mu_lock(&mu_);
+    gpr_atm_no_barrier_store(&count_, UNBLOCKED(0));
+    fork_complete_ = true;
+    gpr_cv_broadcast(&cv_);
+    gpr_mu_unlock(&g_mu);
+  }
+
+  void ~ExecCtxState() {
+    gpr_mu_destroy(&mu_);
+    gpr_cv_destroy(&cv_);
+  }
+}
+
+class ThreadState {
+  public:
+    ThreadState() : awaiting_threads_(false), threads_done_(false), count_(0) {
+      gpr_mu_init(&mu_);
+      gpr_cv_init(&cv_);
+    }
+
+  void IncThreadCount() {
+    gpr_mu_lock(&mu_);
+    count_++;
+    gpr_mu_unlock(&mu_);
+  }
+
+  void DecThreadCount() {
+    gpr_mu_lock(&mu_);
+    count_--;
+    if (awaiting_threads_ && count_ == 0) {
+      threads_done = true;
+      gpr_cv_signal(&cv_);
+    }
+    gpr_mu_unlock(&mu_);
+  }
+  void AwaitThreads() {
+    gpr_mu_lock(&mu_);
+    awaiting_threads_ = true;
+    threads_done_ = (count_ == 0);
+    while (!threads_done_) {
+      gpr_cv_wait(&cv_, &mu_,
+                  gpr_inf_future(GPR_CLOCK_REALTIME));
+    }
+    awaiting_threads_ = true;
+    gpr_mu_unlock(&mu_);
+  }
+
+  ~ThreadState() {
+    gpr_mu_destroy(&mu_);
+    gpr_cv_destroy(&cv_);
+  }
+}
+
+static void Fork::GlobalInit() {
 #ifdef GRPC_ENABLE_FORK_SUPPORT
-  fork_support_enabled = 1;
+  bool supportEnabled_ = true;
 #else
-  fork_support_enabled = 0;
+  bool supportEnabled_ = false;
 #endif
   bool env_var_set = false;
   char* env = gpr_getenv("GRPC_ENABLE_FORK_SUPPORT");
@@ -50,7 +158,7 @@ void grpc_fork_support_init() {
                                    "False", "FALSE", "0"};
     for (size_t i = 0; i < GPR_ARRAY_SIZE(truthy); i++) {
       if (0 == strcmp(env, truthy[i])) {
-        fork_support_enabled = 1;
+        supportEnabled_ = true;
         env_var_set = true;
         break;
       }
@@ -58,7 +166,7 @@ void grpc_fork_support_init() {
     if (!env_var_set) {
       for (size_t i = 0; i < GPR_ARRAY_SIZE(falsey); i++) {
         if (0 == strcmp(env, falsey[i])) {
-          fork_support_enabled = 0;
+          supportEnabled_ = false;
           env_var_set = true;
           break;
         }
@@ -66,13 +174,66 @@ void grpc_fork_support_init() {
     }
     gpr_free(env);
   }
-  if (override_fork_support_enabled != -1) {
-    fork_support_enabled = override_fork_support_enabled;
+  if (overrideEnabled_ != -1) {
+    supportEnabled_ = (overrideEnabled_ == 1);
+  }
+  if (supportEnabled_) {
+    execCtxState_ = grpc_core::New<ExecCtxState>();
+    threadState_ = grpc_core::New<ThreadState>();
   }
 }
 
-int grpc_fork_support_enabled() { return fork_support_enabled; }
+  static void Fork::GlobalShutdown() {
+    if (supportEnabled_) {
+      grpc_core::Delete(execCtxState_);
+      grpc_core::Delete(threadState_);
+    }
+  }
+
+  static bool Fork::Enabled() {
+    return supportEnabled_;
+  }
+
+  // Testing Only
+  static void Fork::Enable(bool enable) {
+    overrideEnabled_ = enable ? 1 : 0;
+  }
+
+  static void Fork::IncExecCtxCount() {
+    if(supportEnabled_) {
+      execCtxState->IncExecCtxCount();
+    }
+  }
+
+  static void Fork::DecExecCtxCount() {
+    if(supportEnabled_) {
+      execCtxState->DecExecCtxCount();
+    }
+  }
+
+  static bool Fork::BlockExecCtx() {
+    if(supportEnabled_) {
+      return execCtxState->BlockExecCtx();
+    }
+    return false;
+  }
+
+  static void Fork::AllowExecCtx() {
+    execCtxState->AllowExecCtx();
+  }
+
+  static void Fork::IncThreadCount() {
+    threadState->IncThreadCount();
+  }
+
+  static void Fork::DecThreadCount() {
+    threadState_->DecThreadCount();
+  }
+  static void Fork::AwaitThreads() {
+    threadState_->AwaitThreads();
+  }
 
-void grpc_enable_fork_support(int enable) {
-  override_fork_support_enabled = enable;
+private:
+  ExecCtxState* execCtxState_;
+  ThreadState* threadState_;
 }
diff --git a/src/core/lib/gpr/fork.h b/src/core/lib/gpr/fork.h
index 94c61bb836b..bf5acc3292d 100644
--- a/src/core/lib/gpr/fork.h
+++ b/src/core/lib/gpr/fork.h
@@ -24,12 +24,59 @@
  *       AROUND VERY SPECIFIC USE CASES.
  */
 
-void grpc_fork_support_init(void);
+namespace grpc_core {
 
-int grpc_fork_support_enabled(void);
+namespace {
+  class ExecCtxState;
+  class ThreadState;
+}
 
-// Test only:  Must be called before grpc_init(), and overrides
-// environment variables/compile flags
-void grpc_enable_fork_support(int enable);
+namespace internal {
+
+class ForkSupport {
+ public:
+  static void GlobalInit();
+  static void GlobalShutdown();
+
+  // Returns true if fork suppport is enabled, false otherwise
+  static bool Enabled();
+
+  // Increment the count of active ExecCtxs.
+  // Will block until a pending fork is complete if one is in progress.
+  void IncExecCtxCount();
+
+  // Decrement the count of active ExecCtxs
+  void DecExecCtxCount();
+
+  // Check if there is a single active ExecCtx
+  // (the one used to invoke this function).  If there are more,
+  // return false.  Otherwise, return true and block creation of
+  // more ExecCtx s until AlloWExecCtx() is called
+  //
+  bool BlockExecCtx();
+  void AllowExecCtx();
+
+  // Increment the count of active threads.
+  void IncThreadCount();
+
+  // Decrement the count of active threads.
+  void DecThreadCount();
+
+  // Await all core threads to be joined.
+  void AwaitThreads();
+
+  // Test only: overrides environment variables/compile flags
+  // Must be called before grpc_init()
+  void Enable(bool enable);
+
+ private:
+  static ExecCtxState* execCtxState_ = nullptr;
+  static ThreadState* threadState_ = nullptr;
+  static bool supportEnabled_ = false;
+  static int overrideEnabled_ = -1;
+}
+
+} // namespace internal
+} // namespace grpc_core
 
 #endif /* GRPC_CORE_LIB_GPR_FORK_H */
diff --git a/src/core/lib/gprpp/thd.h b/src/core/lib/gprpp/thd.h
index 05c7ded45fc..caf0652c1a7 100644
--- a/src/core/lib/gprpp/thd.h
+++ b/src/core/lib/gprpp/thd.h
@@ -111,9 +111,6 @@ class Thread {
     }
   };
 
-  static void Init();
-  static bool AwaitAll(gpr_timespec deadline);
-
  private:
   Thread(const Thread&) = delete;
   Thread& operator=(const Thread&) = delete;
diff --git a/src/core/lib/gprpp/thd_posix.cc b/src/core/lib/gprpp/thd_posix.cc
index 2f6c2edcae1..1a20a0bbc34 100644
--- a/src/core/lib/gprpp/thd_posix.cc
+++ b/src/core/lib/gprpp/thd_posix.cc
@@ -38,11 +38,6 @@
 
 namespace grpc_core {
 namespace {
-gpr_mu g_mu;
-gpr_cv g_cv;
-int g_thread_count;
-int g_awaiting_threads;
-
 class ThreadInternalsPosix;
 struct thd_arg {
   ThreadInternalsPosix* thread;
@@ -68,7 +63,7 @@ class ThreadInternalsPosix
     info->body = thd_body;
     info->arg = arg;
     info->name = thd_name;
-    inc_thd_count();
+    grpc_fork_inc_thd_count();
 
     GPR_ASSERT(pthread_attr_init(&attr) == 0);
     GPR_ASSERT(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE) ==
@@ -103,7 +98,7 @@ class ThreadInternalsPosix
                           gpr_mu_unlock(&arg.thread->mu_);
 
                           (*arg.body)(arg.arg);
-                          dec_thd_count();
+                          grpc_fork_dec_thd_count();
                           return nullptr;
                         },
                         info) == 0);
@@ -113,7 +108,7 @@ class ThreadInternalsPosix
     if (!success) {
       /* don't use gpr_free, as this was allocated using malloc (see above) */
       free(info);
-      dec_thd_count();
+      grpc_fork_dec_thd_count();
     }
   };
 
@@ -132,29 +127,6 @@ class ThreadInternalsPosix
   void Join() override { pthread_join(pthread_id_, nullptr); }
 
  private:
-  /*****************************************
-   * Only used when fork support is enabled
-   */
-
-  static void inc_thd_count() {
-    if (grpc_fork_support_enabled()) {
-      gpr_mu_lock(&g_mu);
-      g_thread_count++;
-      gpr_mu_unlock(&g_mu);
-    }
-  }
-
-  static void dec_thd_count() {
-    if (grpc_fork_support_enabled()) {
-      gpr_mu_lock(&g_mu);
-      g_thread_count--;
-      if (g_awaiting_threads && g_thread_count == 0) {
-        gpr_cv_signal(&g_cv);
-      }
-      gpr_mu_unlock(&g_mu);
-    }
-  }
-
   gpr_mu mu_;
   gpr_cv ready_;
   bool started_;
@@ -180,27 +152,6 @@ Thread::Thread(const char* thd_name, void (*thd_body)(void* arg), void* arg,
     *success = outcome;
   }
 }
-
-void Thread::Init() {
-  gpr_mu_init(&g_mu);
-  gpr_cv_init(&g_cv);
-  g_thread_count = 0;
-  g_awaiting_threads = 0;
-}
-
-bool Thread::AwaitAll(gpr_timespec deadline) {
-  gpr_mu_lock(&g_mu);
-  g_awaiting_threads = 1;
-  int res = 0;
-  while ((g_thread_count > 0) &&
-         (gpr_time_cmp(gpr_now(GPR_CLOCK_REALTIME), deadline) < 0)) {
-    res = gpr_cv_wait(&g_cv, &g_mu, deadline);
-  }
-  g_awaiting_threads = 0;
-  gpr_mu_unlock(&g_mu);
-  return res == 0;
-}
-
 }  // namespace grpc_core
 
 // The following is in the external namespace as it is exposed as C89 API
diff --git a/src/core/lib/gprpp/thd_windows.cc b/src/core/lib/gprpp/thd_windows.cc
index 59ea02f3d22..71584fd358e 100644
--- a/src/core/lib/gprpp/thd_windows.cc
+++ b/src/core/lib/gprpp/thd_windows.cc
@@ -131,13 +131,6 @@ class ThreadInternalsWindows
 
 namespace grpc_core {
 
-void Thread::Init() {}
-
-bool Thread::AwaitAll(gpr_timespec deadline) {
-  // TODO: Consider adding this if needed
-  return false;
-}
-
 Thread::Thread(const char* thd_name, void (*thd_body)(void* arg), void* arg,
                bool* success) {
   bool outcome = false;
diff --git a/src/core/lib/iomgr/exec_ctx.h b/src/core/lib/iomgr/exec_ctx.h
index de97164f02c..b5b59621f9e 100644
--- a/src/core/lib/iomgr/exec_ctx.h
+++ b/src/core/lib/iomgr/exec_ctx.h
@@ -25,6 +25,7 @@
 #include <grpc/support/cpu.h>
 #include <grpc/support/log.h>
 
+#include "src/core/lib/gpr/fork.h"
 #include "src/core/lib/gpr/tls.h"
 #include "src/core/lib/iomgr/closure.h"
 
@@ -76,16 +77,23 @@ class ExecCtx {
  public:
   /** Default Constructor */
 
-  ExecCtx() : flags_(GRPC_EXEC_CTX_FLAG_IS_FINISHED) { Set(this); }
+  ExecCtx() : flags_(GRPC_EXEC_CTX_FLAG_IS_FINISHED) {
+    grpc_fork_inc_exec_ctx_count();
+    Set(this);
+  }
 
   /** Parameterised Constructor */
-  ExecCtx(uintptr_t fl) : flags_(fl) { Set(this); }
+  ExecCtx(uintptr_t fl) : flags_(fl) {
+    grpc_fork_inc_exec_ctx_count();
+    Set(this);
+  }
 
   /** Destructor */
   virtual ~ExecCtx() {
     flags_ |= GRPC_EXEC_CTX_FLAG_IS_FINISHED;
     Flush();
     Set(last_exec_ctx_);
+    grpc_fork_dec_exec_ctx_count();
   }
 
   /** Disallow copy and assignment operators */
diff --git a/src/core/lib/iomgr/fork_posix.cc b/src/core/lib/iomgr/fork_posix.cc
index f8645ab157e..dd0f9f612f7 100644
--- a/src/core/lib/iomgr/fork_posix.cc
+++ b/src/core/lib/iomgr/fork_posix.cc
@@ -41,47 +41,59 @@
  *       AROUND VERY SPECIFIC USE CASES.
  */
 
+namespace {
+bool skipped_handler = true;
+bool registered_handlers = false;
+}  // namespace
+
 void grpc_prefork() {
+  grpc_core::ExecCtx exec_ctx;
+  skipped_handler = true;
+  if (!grpc_is_initialized()) {
+    return;
+  }
   if (!grpc_fork_support_enabled()) {
     gpr_log(GPR_ERROR,
             "Fork support not enabled; try running with the "
             "environment variable GRPC_ENABLE_FORK_SUPPORT=1");
     return;
   }
-  if (grpc_is_initialized()) {
-    grpc_core::ExecCtx exec_ctx;
-    grpc_timer_manager_set_threading(false);
-    grpc_executor_set_threading(false);
-    grpc_core::ExecCtx::Get()->Flush();
-    if (!grpc_core::Thread::AwaitAll(
-            gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
-                         gpr_time_from_seconds(3, GPR_TIMESPAN)))) {
-      gpr_log(GPR_ERROR, "gRPC thread still active! Cannot fork!");
-    }
+  if (!grpc_fork_block_exec_ctx()) {
+    gpr_log(GPR_INFO,
+            "Other threads are currently calling into gRPC, skipping fork() "
+            "handlers");
+    return;
   }
+  grpc_timer_manager_set_threading(false);
+  grpc_executor_set_threading(false);
+  grpc_core::ExecCtx::Get()->Flush();
+  grpc_fork_await_thds();
+  skipped_handler = false;
 }
 
 void grpc_postfork_parent() {
-  if (grpc_is_initialized()) {
-    grpc_timer_manager_set_threading(true);
+  if (!skipped_handler) {
+    grpc_fork_allow_exec_ctx();
     grpc_core::ExecCtx exec_ctx;
+    grpc_timer_manager_set_threading(true);
     grpc_executor_set_threading(true);
   }
 }
 
 void grpc_postfork_child() {
-  if (grpc_is_initialized()) {
-    grpc_timer_manager_set_threading(true);
+  if (!skipped_handler) {
+    grpc_fork_allow_exec_ctx();
     grpc_core::ExecCtx exec_ctx;
+    grpc_timer_manager_set_threading(true);
     grpc_executor_set_threading(true);
-    grpc_core::ExecCtx::Get()->Flush();
   }
 }
 
 void grpc_fork_handlers_auto_register() {
-  if (grpc_fork_support_enabled()) {
+  if (grpc_fork_support_enabled() & !registered_handlers) {
 #ifdef GRPC_POSIX_FORK_ALLOW_PTHREAD_ATFORK
     pthread_atfork(grpc_prefork, grpc_postfork_parent, grpc_postfork_child);
+    registered_handlers = true;
 #endif  // GRPC_POSIX_FORK_ALLOW_PTHREAD_ATFORK
   }
 }
diff --git a/src/core/lib/surface/init.cc b/src/core/lib/surface/init.cc
index ac9f9e6066f..285e6f7ddc7 100644
--- a/src/core/lib/surface/init.cc
+++ b/src/core/lib/surface/init.cc
@@ -64,12 +64,10 @@ static int g_initializations;
 
 static void do_basic_init(void) {
   gpr_log_verbosity_init();
-  grpc_fork_support_init();
   gpr_mu_init(&g_init_mu);
   grpc_register_built_in_plugins();
   grpc_cq_global_init();
   g_initializations = 0;
-  grpc_fork_handlers_auto_register();
 }
 
 static bool append_filter(grpc_channel_stack_builder* builder, void* arg) {
@@ -122,8 +120,9 @@ void grpc_init(void) {
 
   gpr_mu_lock(&g_init_mu);
   if (++g_initializations == 1) {
+    grpc_fork_support_init();
+    grpc_fork_handlers_auto_register();
     gpr_time_init();
-    grpc_core::Thread::Init();
     grpc_stats_init();
     grpc_slice_intern_init();
     grpc_mdctx_global_init();
@@ -177,6 +176,7 @@ void grpc_shutdown(void) {
       grpc_handshaker_factory_registry_shutdown();
       grpc_slice_intern_shutdown();
       grpc_stats_shutdown();
+      grpc_fork_support_destroy();
     }
     grpc_core::ExecCtx::GlobalShutdown();
   }
diff --git a/test/core/gpr/BUILD b/test/core/gpr/BUILD
index 5308ea09348..2aeccc0a0f7 100644
--- a/test/core/gpr/BUILD
+++ b/test/core/gpr/BUILD
@@ -58,6 +58,16 @@ grpc_cc_test(
     ],
 )
 
+grpc_cc_test(
+    name = "fork_test",
+    srcs = ["fork_test.cc"],
+    language = "C++",
+    deps = [
+        "//:gpr",
+        "//test/core/util:gpr_test_util",
+    ],
+)
+
 grpc_cc_test(
     name = "host_port_test",
     srcs = ["host_port_test.cc"],
diff --git a/test/core/gpr/fork_test.cc b/test/core/gpr/fork_test.cc
new file mode 100644
index 00000000000..bc388c4a77f
--- /dev/null
+++ b/test/core/gpr/fork_test.cc
@@ -0,0 +1,136 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "src/core/lib/gpr/fork.h"
+
+#include "src/core/lib/gprpp/thd.h"
+#include "test/core/util/test_config.h"
+
+static void test_init() {
+  GPR_ASSERT(!grpc_fork_support_enabled());
+
+  // Default fork support (disabled)
+  grpc_fork_support_init();
+  GPR_ASSERT(!grpc_fork_support_enabled());
+  grpc_fork_support_destroy();
+
+  // Explicitly disabled fork support
+  grpc_enable_fork_support(false);
+  grpc_fork_support_init();
+  GPR_ASSERT(!grpc_fork_support_enabled());
+  grpc_fork_support_destroy();
+
+  // Explicitly enabled fork support
+  grpc_enable_fork_support(true);
+  grpc_fork_support_init();
+  GPR_ASSERT(grpc_fork_support_enabled());
+  grpc_fork_support_destroy();
+}
+
+#define THREAD_DELAY_MS 3000
+#define THREAD_DELAY_EPSILON 500
+#define CONCURRENT_TEST_THREADS 100
+
+static void sleeping_thd(void* arg) {
+  int64_t sleep_ms = (int64_t)arg;
+  gpr_sleep_until(gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                               gpr_time_from_millis(sleep_ms, GPR_TIMESPAN)));
+}
+
+static void test_thd_count() {
+  // Test no active threads
+  grpc_enable_fork_support(true);
+  grpc_fork_support_init();
+  grpc_fork_await_thds();
+  grpc_fork_support_destroy();
+
+  grpc_enable_fork_support(true);
+  grpc_fork_support_init();
+  grpc_core::Thread thds[CONCURRENT_TEST_THREADS];
+  gpr_timespec est_end_time =
+      gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                   gpr_time_from_millis(THREAD_DELAY_MS, GPR_TIMESPAN));
+  gpr_timespec tolerance =
+      gpr_time_from_millis(THREAD_DELAY_EPSILON, GPR_TIMESPAN);
+  for (int i = 0; i < CONCURRENT_TEST_THREADS; i++) {
+    intptr_t sleep_time_ms =
+        (i * THREAD_DELAY_MS) / (CONCURRENT_TEST_THREADS - 1);
+    thds[i] =
+        grpc_core::Thread("grpc_fork_test", sleeping_thd, (void*)sleep_time_ms);
+    thds[i].Start();
+  }
+  grpc_fork_await_thds();
+  gpr_timespec end_time = gpr_now(GPR_CLOCK_REALTIME);
+  for (auto& thd : thds) {
+    thd.Join();
+  }
+  GPR_ASSERT(gpr_time_similar(end_time, est_end_time, tolerance));
+  grpc_fork_support_destroy();
+}
+
+static void exec_ctx_thread(void* arg) {
+  bool* exec_ctx_created = (bool*)arg;
+  grpc_fork_inc_exec_ctx_count();
+  *exec_ctx_created = true;
+}
+
+static void test_exec_count() {
+  grpc_fork_inc_exec_ctx_count();
+  grpc_enable_fork_support(true);
+  grpc_fork_support_init();
+
+  grpc_fork_inc_exec_ctx_count();
+  GPR_ASSERT(grpc_fork_block_exec_ctx());
+  grpc_fork_dec_exec_ctx_count();
+  grpc_fork_allow_exec_ctx();
+
+  grpc_fork_inc_exec_ctx_count();
+  grpc_fork_inc_exec_ctx_count();
+  GPR_ASSERT(!grpc_fork_block_exec_ctx());
+  grpc_fork_dec_exec_ctx_count();
+  grpc_fork_dec_exec_ctx_count();
+
+  grpc_fork_inc_exec_ctx_count();
+  GPR_ASSERT(grpc_fork_block_exec_ctx());
+  grpc_fork_dec_exec_ctx_count();
+  grpc_fork_allow_exec_ctx();
+
+  // Test that block_exec_ctx() blocks grpc_fork_inc_exec_ctx_count
+  bool exec_ctx_created = false;
+  grpc_core::Thread thd =
+      grpc_core::Thread("grpc_fork_test", exec_ctx_thread, &exec_ctx_created);
+  grpc_fork_inc_exec_ctx_count();
+  GPR_ASSERT(grpc_fork_block_exec_ctx());
+  grpc_fork_dec_exec_ctx_count();
+  thd.Start();
+  gpr_sleep_until(gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                               gpr_time_from_seconds(1, GPR_TIMESPAN)));
+  GPR_ASSERT(!exec_ctx_created);
+  grpc_fork_allow_exec_ctx();
+  thd.Join();  // This ensure that the call got un-blocked
+  grpc_fork_support_destroy();
+}
+
+int main(int argc, char* argv[]) {
+  grpc_test_init(argc, argv);
+  test_init();
+  test_thd_count();
+  test_exec_count();
+
+  return 0;
+}
diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json
index 724967145ea..0ddecffa5f6 100644
--- a/tools/run_tests/generated/sources_and_headers.json
+++ b/tools/run_tests/generated/sources_and_headers.json
@@ -602,6 +602,21 @@
     "third_party": false, 
     "type": "target"
   }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c", 
+    "name": "fork_test", 
+    "src": [
+      "test/core/gpr/fork_test.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
   {
     "deps": [
       "gpr", 
diff --git a/tools/run_tests/generated/tests.json b/tools/run_tests/generated/tests.json
index b7fdb6f5794..c50fe073416 100644
--- a/tools/run_tests/generated/tests.json
+++ b/tools/run_tests/generated/tests.json
@@ -743,6 +743,26 @@
     ], 
     "uses_polling": true
   }, 
+  {
+    "args": [], 
+    "benchmark": false, 
+    "ci_platforms": [
+      "linux", 
+      "mac"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "gtest": false, 
+    "language": "c", 
+    "name": "fork_test", 
+    "platforms": [
+      "linux", 
+      "mac"
+    ], 
+    "uses_polling": false
+  }, 
   {
     "args": [], 
     "benchmark": false, 

From 701e70da071ef91152c30aad813e2ed405c05c59 Mon Sep 17 00:00:00 2001
From: kpayson64 <kpayson@google.com>
Date: Mon, 30 Apr 2018 17:40:00 -0700
Subject: [PATCH 2/6] c++ify

---
 BUILD                                         |   4 +-
 CMakeLists.txt                                |   4 +-
 Makefile                                      |   6 +-
 build.yaml                                    |   6 +-
 config.m4                                     |   2 +-
 config.w32                                    |   2 +-
 gRPC-C++.podspec                              |   4 +-
 gRPC-Core.podspec                             |   6 +-
 grpc.gemspec                                  |   4 +-
 grpc.gyp                                      |   2 +-
 package.xml                                   |   4 +-
 src/core/lib/{gpr => gprpp}/fork.cc           | 153 +++++++++---------
 src/core/lib/{gpr => gprpp}/fork.h            |  41 +++--
 src/core/lib/gprpp/thd_posix.cc               |   8 +-
 src/core/lib/iomgr/exec_ctx.h                 |   8 +-
 src/core/lib/iomgr/fork_posix.cc              |  14 +-
 src/core/lib/surface/init.cc                  |   7 +-
 src/python/grpcio/grpc_core_dependencies.py   |   2 +-
 test/core/{gpr => gprpp}/fork_test.cc         |  96 +++++------
 tools/doxygen/Doxyfile.c++.internal           |   2 +-
 tools/doxygen/Doxyfile.core.internal          |   4 +-
 .../generated/sources_and_headers.json        |   8 +-
 22 files changed, 192 insertions(+), 195 deletions(-)
 rename src/core/lib/{gpr => gprpp}/fork.cc (62%)
 rename src/core/lib/{gpr => gprpp}/fork.h (76%)
 rename test/core/{gpr => gprpp}/fork_test.cc (60%)

diff --git a/BUILD b/BUILD
index 9c99f95fcdf..45c8f406927 100644
--- a/BUILD
+++ b/BUILD
@@ -511,7 +511,6 @@ grpc_cc_library(
         "src/core/lib/gpr/env_linux.cc",
         "src/core/lib/gpr/env_posix.cc",
         "src/core/lib/gpr/env_windows.cc",
-        "src/core/lib/gpr/fork.cc",
         "src/core/lib/gpr/host_port.cc",
         "src/core/lib/gpr/log.cc",
         "src/core/lib/gpr/log_android.cc",
@@ -536,6 +535,7 @@ grpc_cc_library(
         "src/core/lib/gpr/tmpfile_posix.cc",
         "src/core/lib/gpr/tmpfile_windows.cc",
         "src/core/lib/gpr/wrap_memcpy.cc",
+        "src/core/lib/gprpp/fork.cc",
         "src/core/lib/gprpp/thd_posix.cc",
         "src/core/lib/gprpp/thd_windows.cc",
         "src/core/lib/profiling/basic_timers.cc",
@@ -544,7 +544,6 @@ grpc_cc_library(
     hdrs = [
         "src/core/lib/gpr/arena.h",
         "src/core/lib/gpr/env.h",
-        "src/core/lib/gpr/fork.h",
         "src/core/lib/gpr/host_port.h",
         "src/core/lib/gpr/mpscq.h",
         "src/core/lib/gpr/murmur_hash.h",
@@ -559,6 +558,7 @@ grpc_cc_library(
         "src/core/lib/gpr/tmpfile.h",
         "src/core/lib/gpr/useful.h",
         "src/core/lib/gprpp/abstract.h",
+        "src/core/lib/gprpp/fork.h",
         "src/core/lib/gprpp/manual_constructor.h",
         "src/core/lib/gprpp/memory.h",
         "src/core/lib/gprpp/thd.h",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index aa4dbb4f9b3..b58065b1119 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -703,7 +703,6 @@ add_library(gpr
   src/core/lib/gpr/env_linux.cc
   src/core/lib/gpr/env_posix.cc
   src/core/lib/gpr/env_windows.cc
-  src/core/lib/gpr/fork.cc
   src/core/lib/gpr/host_port.cc
   src/core/lib/gpr/log.cc
   src/core/lib/gpr/log_android.cc
@@ -728,6 +727,7 @@ add_library(gpr
   src/core/lib/gpr/tmpfile_posix.cc
   src/core/lib/gpr/tmpfile_windows.cc
   src/core/lib/gpr/wrap_memcpy.cc
+  src/core/lib/gprpp/fork.cc
   src/core/lib/gprpp/thd_posix.cc
   src/core/lib/gprpp/thd_windows.cc
   src/core/lib/profiling/basic_timers.cc
@@ -6161,7 +6161,7 @@ if (gRPC_BUILD_TESTS)
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC)
 
 add_executable(fork_test
-  test/core/gpr/fork_test.cc
+  test/core/gprpp/fork_test.cc
 )
 
 
diff --git a/Makefile b/Makefile
index 631ecf9f96e..83941022698 100644
--- a/Makefile
+++ b/Makefile
@@ -3035,7 +3035,6 @@ LIBGPR_SRC = \
     src/core/lib/gpr/env_linux.cc \
     src/core/lib/gpr/env_posix.cc \
     src/core/lib/gpr/env_windows.cc \
-    src/core/lib/gpr/fork.cc \
     src/core/lib/gpr/host_port.cc \
     src/core/lib/gpr/log.cc \
     src/core/lib/gpr/log_android.cc \
@@ -3060,6 +3059,7 @@ LIBGPR_SRC = \
     src/core/lib/gpr/tmpfile_posix.cc \
     src/core/lib/gpr/tmpfile_windows.cc \
     src/core/lib/gpr/wrap_memcpy.cc \
+    src/core/lib/gprpp/fork.cc \
     src/core/lib/gprpp/thd_posix.cc \
     src/core/lib/gprpp/thd_windows.cc \
     src/core/lib/profiling/basic_timers.cc \
@@ -10959,7 +10959,7 @@ endif
 
 
 FORK_TEST_SRC = \
-    test/core/gpr/fork_test.cc \
+    test/core/gprpp/fork_test.cc \
 
 FORK_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(FORK_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@@ -10979,7 +10979,7 @@ $(BINDIR)/$(CONFIG)/fork_test: $(FORK_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgpr_test
 
 endif
 
-$(OBJDIR)/$(CONFIG)/test/core/gpr/fork_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gprpp/fork_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
 
 deps_fork_test: $(FORK_TEST_OBJS:.o=.dep)
 
diff --git a/build.yaml b/build.yaml
index 0d8846bcd1c..890ebb06c48 100644
--- a/build.yaml
+++ b/build.yaml
@@ -121,7 +121,6 @@ filegroups:
   - src/core/lib/gpr/env_linux.cc
   - src/core/lib/gpr/env_posix.cc
   - src/core/lib/gpr/env_windows.cc
-  - src/core/lib/gpr/fork.cc
   - src/core/lib/gpr/host_port.cc
   - src/core/lib/gpr/log.cc
   - src/core/lib/gpr/log_android.cc
@@ -146,6 +145,7 @@ filegroups:
   - src/core/lib/gpr/tmpfile_posix.cc
   - src/core/lib/gpr/tmpfile_windows.cc
   - src/core/lib/gpr/wrap_memcpy.cc
+  - src/core/lib/gprpp/fork.cc
   - src/core/lib/gprpp/thd_posix.cc
   - src/core/lib/gprpp/thd_windows.cc
   - src/core/lib/profiling/basic_timers.cc
@@ -174,7 +174,6 @@ filegroups:
   headers:
   - src/core/lib/gpr/arena.h
   - src/core/lib/gpr/env.h
-  - src/core/lib/gpr/fork.h
   - src/core/lib/gpr/host_port.h
   - src/core/lib/gpr/mpscq.h
   - src/core/lib/gpr/murmur_hash.h
@@ -192,6 +191,7 @@ filegroups:
   - src/core/lib/gprpp/atomic.h
   - src/core/lib/gprpp/atomic_with_atm.h
   - src/core/lib/gprpp/atomic_with_std.h
+  - src/core/lib/gprpp/fork.h
   - src/core/lib/gprpp/manual_constructor.h
   - src/core/lib/gprpp/memory.h
   - src/core/lib/gprpp/thd.h
@@ -2320,7 +2320,7 @@ targets:
   build: test
   language: c
   src:
-  - test/core/gpr/fork_test.cc
+  - test/core/gprpp/fork_test.cc
   deps:
   - gpr_test_util
   - gpr
diff --git a/config.m4 b/config.m4
index 57fc2dbab92..17d2f9c1a65 100644
--- a/config.m4
+++ b/config.m4
@@ -49,7 +49,6 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/gpr/env_linux.cc \
     src/core/lib/gpr/env_posix.cc \
     src/core/lib/gpr/env_windows.cc \
-    src/core/lib/gpr/fork.cc \
     src/core/lib/gpr/host_port.cc \
     src/core/lib/gpr/log.cc \
     src/core/lib/gpr/log_android.cc \
@@ -74,6 +73,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/gpr/tmpfile_posix.cc \
     src/core/lib/gpr/tmpfile_windows.cc \
     src/core/lib/gpr/wrap_memcpy.cc \
+    src/core/lib/gprpp/fork.cc \
     src/core/lib/gprpp/thd_posix.cc \
     src/core/lib/gprpp/thd_windows.cc \
     src/core/lib/profiling/basic_timers.cc \
diff --git a/config.w32 b/config.w32
index 580607dd3de..7c5a76acef9 100644
--- a/config.w32
+++ b/config.w32
@@ -26,7 +26,6 @@ if (PHP_GRPC != "no") {
     "src\\core\\lib\\gpr\\env_linux.cc " +
     "src\\core\\lib\\gpr\\env_posix.cc " +
     "src\\core\\lib\\gpr\\env_windows.cc " +
-    "src\\core\\lib\\gpr\\fork.cc " +
     "src\\core\\lib\\gpr\\host_port.cc " +
     "src\\core\\lib\\gpr\\log.cc " +
     "src\\core\\lib\\gpr\\log_android.cc " +
@@ -51,6 +50,7 @@ if (PHP_GRPC != "no") {
     "src\\core\\lib\\gpr\\tmpfile_posix.cc " +
     "src\\core\\lib\\gpr\\tmpfile_windows.cc " +
     "src\\core\\lib\\gpr\\wrap_memcpy.cc " +
+    "src\\core\\lib\\gprpp\\fork.cc " +
     "src\\core\\lib\\gprpp\\thd_posix.cc " +
     "src\\core\\lib\\gprpp\\thd_windows.cc " +
     "src\\core\\lib\\profiling\\basic_timers.cc " +
diff --git a/gRPC-C++.podspec b/gRPC-C++.podspec
index 65a5dc66b4c..22428cc03db 100644
--- a/gRPC-C++.podspec
+++ b/gRPC-C++.podspec
@@ -213,7 +213,6 @@ Pod::Spec.new do |s|
                       'src/cpp/codegen/codegen_init.cc',
                       'src/core/lib/gpr/arena.h',
                       'src/core/lib/gpr/env.h',
-                      'src/core/lib/gpr/fork.h',
                       'src/core/lib/gpr/host_port.h',
                       'src/core/lib/gpr/mpscq.h',
                       'src/core/lib/gpr/murmur_hash.h',
@@ -231,6 +230,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/gprpp/atomic.h',
                       'src/core/lib/gprpp/atomic_with_atm.h',
                       'src/core/lib/gprpp/atomic_with_std.h',
+                      'src/core/lib/gprpp/fork.h',
                       'src/core/lib/gprpp/manual_constructor.h',
                       'src/core/lib/gprpp/memory.h',
                       'src/core/lib/gprpp/thd.h',
@@ -495,7 +495,6 @@ Pod::Spec.new do |s|
                               'src/cpp/thread_manager/thread_manager.h',
                               'src/core/lib/gpr/arena.h',
                               'src/core/lib/gpr/env.h',
-                              'src/core/lib/gpr/fork.h',
                               'src/core/lib/gpr/host_port.h',
                               'src/core/lib/gpr/mpscq.h',
                               'src/core/lib/gpr/murmur_hash.h',
@@ -513,6 +512,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/gprpp/atomic.h',
                               'src/core/lib/gprpp/atomic_with_atm.h',
                               'src/core/lib/gprpp/atomic_with_std.h',
+                              'src/core/lib/gprpp/fork.h',
                               'src/core/lib/gprpp/manual_constructor.h',
                               'src/core/lib/gprpp/memory.h',
                               'src/core/lib/gprpp/thd.h',
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index 7f61719cb16..631dfed013a 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -185,7 +185,6 @@ Pod::Spec.new do |s|
     # To save you from scrolling, this is the last part of the podspec.
     ss.source_files = 'src/core/lib/gpr/arena.h',
                       'src/core/lib/gpr/env.h',
-                      'src/core/lib/gpr/fork.h',
                       'src/core/lib/gpr/host_port.h',
                       'src/core/lib/gpr/mpscq.h',
                       'src/core/lib/gpr/murmur_hash.h',
@@ -203,6 +202,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/gprpp/atomic.h',
                       'src/core/lib/gprpp/atomic_with_atm.h',
                       'src/core/lib/gprpp/atomic_with_std.h',
+                      'src/core/lib/gprpp/fork.h',
                       'src/core/lib/gprpp/manual_constructor.h',
                       'src/core/lib/gprpp/memory.h',
                       'src/core/lib/gprpp/thd.h',
@@ -217,7 +217,6 @@ Pod::Spec.new do |s|
                       'src/core/lib/gpr/env_linux.cc',
                       'src/core/lib/gpr/env_posix.cc',
                       'src/core/lib/gpr/env_windows.cc',
-                      'src/core/lib/gpr/fork.cc',
                       'src/core/lib/gpr/host_port.cc',
                       'src/core/lib/gpr/log.cc',
                       'src/core/lib/gpr/log_android.cc',
@@ -242,6 +241,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/gpr/tmpfile_posix.cc',
                       'src/core/lib/gpr/tmpfile_windows.cc',
                       'src/core/lib/gpr/wrap_memcpy.cc',
+                      'src/core/lib/gprpp/fork.cc',
                       'src/core/lib/gprpp/thd_posix.cc',
                       'src/core/lib/gprpp/thd_windows.cc',
                       'src/core/lib/profiling/basic_timers.cc',
@@ -778,7 +778,6 @@ Pod::Spec.new do |s|
 
     ss.private_header_files = 'src/core/lib/gpr/arena.h',
                               'src/core/lib/gpr/env.h',
-                              'src/core/lib/gpr/fork.h',
                               'src/core/lib/gpr/host_port.h',
                               'src/core/lib/gpr/mpscq.h',
                               'src/core/lib/gpr/murmur_hash.h',
@@ -796,6 +795,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/gprpp/atomic.h',
                               'src/core/lib/gprpp/atomic_with_atm.h',
                               'src/core/lib/gprpp/atomic_with_std.h',
+                              'src/core/lib/gprpp/fork.h',
                               'src/core/lib/gprpp/manual_constructor.h',
                               'src/core/lib/gprpp/memory.h',
                               'src/core/lib/gprpp/thd.h',
diff --git a/grpc.gemspec b/grpc.gemspec
index 3df7cea33fb..d85d7af4eb6 100644
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -76,7 +76,6 @@ Gem::Specification.new do |s|
   s.files += %w( include/grpc/impl/codegen/sync_windows.h )
   s.files += %w( src/core/lib/gpr/arena.h )
   s.files += %w( src/core/lib/gpr/env.h )
-  s.files += %w( src/core/lib/gpr/fork.h )
   s.files += %w( src/core/lib/gpr/host_port.h )
   s.files += %w( src/core/lib/gpr/mpscq.h )
   s.files += %w( src/core/lib/gpr/murmur_hash.h )
@@ -94,6 +93,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/gprpp/atomic.h )
   s.files += %w( src/core/lib/gprpp/atomic_with_atm.h )
   s.files += %w( src/core/lib/gprpp/atomic_with_std.h )
+  s.files += %w( src/core/lib/gprpp/fork.h )
   s.files += %w( src/core/lib/gprpp/manual_constructor.h )
   s.files += %w( src/core/lib/gprpp/memory.h )
   s.files += %w( src/core/lib/gprpp/thd.h )
@@ -108,7 +108,6 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/gpr/env_linux.cc )
   s.files += %w( src/core/lib/gpr/env_posix.cc )
   s.files += %w( src/core/lib/gpr/env_windows.cc )
-  s.files += %w( src/core/lib/gpr/fork.cc )
   s.files += %w( src/core/lib/gpr/host_port.cc )
   s.files += %w( src/core/lib/gpr/log.cc )
   s.files += %w( src/core/lib/gpr/log_android.cc )
@@ -133,6 +132,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/gpr/tmpfile_posix.cc )
   s.files += %w( src/core/lib/gpr/tmpfile_windows.cc )
   s.files += %w( src/core/lib/gpr/wrap_memcpy.cc )
+  s.files += %w( src/core/lib/gprpp/fork.cc )
   s.files += %w( src/core/lib/gprpp/thd_posix.cc )
   s.files += %w( src/core/lib/gprpp/thd_windows.cc )
   s.files += %w( src/core/lib/profiling/basic_timers.cc )
diff --git a/grpc.gyp b/grpc.gyp
index 38597a5b4f3..d1acde001b3 100644
--- a/grpc.gyp
+++ b/grpc.gyp
@@ -182,7 +182,6 @@
         'src/core/lib/gpr/env_linux.cc',
         'src/core/lib/gpr/env_posix.cc',
         'src/core/lib/gpr/env_windows.cc',
-        'src/core/lib/gpr/fork.cc',
         'src/core/lib/gpr/host_port.cc',
         'src/core/lib/gpr/log.cc',
         'src/core/lib/gpr/log_android.cc',
@@ -207,6 +206,7 @@
         'src/core/lib/gpr/tmpfile_posix.cc',
         'src/core/lib/gpr/tmpfile_windows.cc',
         'src/core/lib/gpr/wrap_memcpy.cc',
+        'src/core/lib/gprpp/fork.cc',
         'src/core/lib/gprpp/thd_posix.cc',
         'src/core/lib/gprpp/thd_windows.cc',
         'src/core/lib/profiling/basic_timers.cc',
diff --git a/package.xml b/package.xml
index c4a6f6fc92d..83ad34ee66a 100644
--- a/package.xml
+++ b/package.xml
@@ -83,7 +83,6 @@
     <file baseinstalldir="/" name="include/grpc/impl/codegen/sync_windows.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/arena.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/env.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/gpr/fork.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/host_port.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/mpscq.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/murmur_hash.h" role="src" />
@@ -101,6 +100,7 @@
     <file baseinstalldir="/" name="src/core/lib/gprpp/atomic.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gprpp/atomic_with_atm.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gprpp/atomic_with_std.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/fork.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gprpp/manual_constructor.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gprpp/memory.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gprpp/thd.h" role="src" />
@@ -115,7 +115,6 @@
     <file baseinstalldir="/" name="src/core/lib/gpr/env_linux.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/env_posix.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/env_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/gpr/fork.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/host_port.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/log.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/log_android.cc" role="src" />
@@ -140,6 +139,7 @@
     <file baseinstalldir="/" name="src/core/lib/gpr/tmpfile_posix.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/tmpfile_windows.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gpr/wrap_memcpy.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/fork.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gprpp/thd_posix.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/gprpp/thd_windows.cc" role="src" />
     <file baseinstalldir="/" name="src/core/lib/profiling/basic_timers.cc" role="src" />
diff --git a/src/core/lib/gpr/fork.cc b/src/core/lib/gprpp/fork.cc
similarity index 62%
rename from src/core/lib/gpr/fork.cc
rename to src/core/lib/gprpp/fork.cc
index ec25848bd02..78f6a2fa0d2 100644
--- a/src/core/lib/gpr/fork.cc
+++ b/src/core/lib/gprpp/fork.cc
@@ -18,7 +18,7 @@
 
 #include <grpc/support/port_platform.h>
 
-#include "src/core/lib/gpr/fork.h"
+#include "src/core/lib/gprpp/fork.h"
 
 #include <string.h>
 
@@ -28,12 +28,15 @@
 
 #include "src/core/lib/gpr/env.h"
 #include "src/core/lib/gpr/useful.h"
+#include "src/core/lib/gprpp/memory.h"
 
 /*
  * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK
  *       AROUND VERY SPECIFIC USE CASES.
  */
 
+namespace grpc_core {
+namespace internal {
 // The exec_ctx_count has 2 modes, blocked and unblocked.
 // When unblocked, the count is 2-indexed; exec_ctx_count=2 indicates
 // 0 active ExecCtxs, exex_ctx_count=3 indicates 1 active ExecCtxs...
@@ -45,16 +48,15 @@
 #define BLOCKED(n) (n)
 
 class ExecCtxState {
-  public:
-    ExecCtxState() : fork_complete_(true) {
-      gpr_mu_init(&mu_);
-      gpr_cv_init(&cv_);
-      gpr_atm_no_barrier_store(&count_, UNBLOCKED(0));
-    }
+ public:
+  ExecCtxState() : fork_complete_(true) {
+    gpr_mu_init(&mu_);
+    gpr_cv_init(&cv_);
+    gpr_atm_no_barrier_store(&count_, UNBLOCKED(0));
+  }
 
   void IncExecCtxCount() {
-    intptr_t count = static_cast<intptr_t>(
-        gpr_atm_no_barrier_load(&count_));
+    intptr_t count = static_cast<intptr_t>(gpr_atm_no_barrier_load(&count_));
     while (true) {
       if (count <= BLOCKED(1)) {
         // This only occurs if we are trying to fork.  Wait until the fork()
@@ -62,27 +64,22 @@ class ExecCtxState {
         gpr_mu_lock(&mu_);
         if (gpr_atm_no_barrier_load(&count_) <= BLOCKED(1)) {
           while (!fork_complete_) {
-            gpr_cv_wait(&cv_, &mu_,
-                        gpr_inf_future(GPR_CLOCK_REALTIME));
+            gpr_cv_wait(&cv_, &mu_, gpr_inf_future(GPR_CLOCK_REALTIME));
           }
         }
         gpr_mu_unlock(&mu_);
-      } else if (gpr_atm_no_barrier_cas(&count_, count,
-                                        count + 1)) {
+      } else if (gpr_atm_no_barrier_cas(&count_, count, count + 1)) {
         break;
       }
       count = gpr_atm_no_barrier_load(&count_);
     }
   }
 
-  void DecExecCtxCount() {
-    gpr_atm_no_barrier_fetch_add(&count_, -1);
-  }
+  void DecExecCtxCount() { gpr_atm_no_barrier_fetch_add(&count_, -1); }
 
   bool BlockExecCtx() {
     // Assumes there is an active ExecCtx when this function is called
-    if (gpr_atm_no_barrier_cas(&count_, UNBLOCKED(1),
-                               BLOCKED(1))) {
+    if (gpr_atm_no_barrier_cas(&count_, UNBLOCKED(1), BLOCKED(1))) {
       fork_complete_ = false;
       return true;
     }
@@ -94,21 +91,27 @@ class ExecCtxState {
     gpr_atm_no_barrier_store(&count_, UNBLOCKED(0));
     fork_complete_ = true;
     gpr_cv_broadcast(&cv_);
-    gpr_mu_unlock(&g_mu);
+    gpr_mu_unlock(&mu_);
   }
 
-  void ~ExecCtxState() {
+  ~ExecCtxState() {
     gpr_mu_destroy(&mu_);
     gpr_cv_destroy(&cv_);
   }
-}
+
+ private:
+  bool fork_complete_;
+  gpr_mu mu_;
+  gpr_cv cv_;
+  gpr_atm count_;
+};
 
 class ThreadState {
-  public:
-    ThreadState() : awaiting_threads_(false), threads_done_(false), count_(0) {
-      gpr_mu_init(&mu_);
-      gpr_cv_init(&cv_);
-    }
+ public:
+  ThreadState() : awaiting_threads_(false), threads_done_(false), count_(0) {
+    gpr_mu_init(&mu_);
+    gpr_cv_init(&cv_);
+  }
 
   void IncThreadCount() {
     gpr_mu_lock(&mu_);
@@ -120,7 +123,7 @@ class ThreadState {
     gpr_mu_lock(&mu_);
     count_--;
     if (awaiting_threads_ && count_ == 0) {
-      threads_done = true;
+      threads_done_ = true;
       gpr_cv_signal(&cv_);
     }
     gpr_mu_unlock(&mu_);
@@ -130,8 +133,7 @@ class ThreadState {
     awaiting_threads_ = true;
     threads_done_ = (count_ == 0);
     while (!threads_done_) {
-      gpr_cv_wait(&cv_, &mu_,
-                  gpr_inf_future(GPR_CLOCK_REALTIME));
+      gpr_cv_wait(&cv_, &mu_, gpr_inf_future(GPR_CLOCK_REALTIME));
     }
     awaiting_threads_ = true;
     gpr_mu_unlock(&mu_);
@@ -141,13 +143,22 @@ class ThreadState {
     gpr_mu_destroy(&mu_);
     gpr_cv_destroy(&cv_);
   }
-}
 
-static void Fork::GlobalInit() {
+ private:
+  bool awaiting_threads_;
+  bool threads_done_;
+  gpr_mu mu_;
+  gpr_cv cv_;
+  int count_;
+};
+
+}  // namespace
+
+void Fork::GlobalInit() {
 #ifdef GRPC_ENABLE_FORK_SUPPORT
-  bool supportEnabled_ = true;
+  supportEnabled_ = true;
 #else
-  bool supportEnabled_ = false;
+  supportEnabled_ = false;
 #endif
   bool env_var_set = false;
   char* env = gpr_getenv("GRPC_ENABLE_FORK_SUPPORT");
@@ -178,62 +189,52 @@ static void Fork::GlobalInit() {
     supportEnabled_ = (overrideEnabled_ == 1);
   }
   if (supportEnabled_) {
-    execCtxState_ = grpc_core::New<ExecCtxState>();
-    threadState_ = grpc_core::New<ThreadState>();
+    execCtxState_ = grpc_core::New<internal::ExecCtxState>();
+    threadState_ = grpc_core::New<internal::ThreadState>();
   }
 }
 
-  static void Fork::GlobalShutdown() {
-    if (supportEnabled_) {
-      grpc_core::Delete(execCtxState_);
-      grpc_core::Delete(threadState_);
-    }
+void Fork::GlobalShutdown() {
+  if (supportEnabled_) {
+    grpc_core::Delete(execCtxState_);
+    grpc_core::Delete(threadState_);
   }
+}
 
-  static bool Fork::Enabled() {
-    return supportEnabled_;
-  }
+bool Fork::Enabled() { return supportEnabled_; }
 
-  // Testing Only
-  static void Fork::Enable(bool enable) {
-    overrideEnabled_ = enable ? 1 : 0;
-  }
+// Testing Only
+void Fork::Enable(bool enable) { overrideEnabled_ = enable ? 1 : 0; }
 
-  static void Fork::IncExecCtxCount() {
-    if(supportEnabled_) {
-      execCtxState->IncExecCtxCount();
-    }
+void Fork::IncExecCtxCount() {
+  if (supportEnabled_) {
+    execCtxState_->IncExecCtxCount();
   }
+}
 
-  static void Fork::DecExecCtxCount() {
-    if(supportEnabled_) {
-      execCtxState->DecExecCtxCount();
-    }
+void Fork::DecExecCtxCount() {
+  if (supportEnabled_) {
+    execCtxState_->DecExecCtxCount();
   }
+}
 
-  static bool Fork::BlockExecCtx() {
-    if(supportEnabled_) {
-      return execCtxState->BlockExecCtx();
-    }
-    return false;
+bool Fork::BlockExecCtx() {
+  if (supportEnabled_) {
+    return execCtxState_->BlockExecCtx();
   }
+  return false;
+}
 
-  static void Fork::AllowExecCtx() {
-    execCtxState->AllowExecCtx();
-  }
+void Fork::AllowExecCtx() { execCtxState_->AllowExecCtx(); }
 
-  static void Fork::IncThreadCount() {
-    threadState->IncThreadCount();
-  }
+void Fork::IncThreadCount() { threadState_->IncThreadCount(); }
 
-  static void Fork::DecThreadCount() {
-    threadState_->DecThreadCount();
-  }
-  static void Fork::AwaitThreads() {
-    threadState_->AwaitThreads();
-  }
+void Fork::DecThreadCount() { threadState_->DecThreadCount(); }
+void Fork::AwaitThreads() { threadState_->AwaitThreads(); }
 
-private:
-  ExecCtxState* execCtxState_;
-  ThreadState* threadState_;
-}
+internal::ExecCtxState* Fork::execCtxState_ = nullptr;
+internal::ThreadState* Fork::threadState_ = nullptr;
+bool Fork::supportEnabled_ = false;
+int Fork::overrideEnabled_ = -1;
+
+}  // namespace grpc_core
diff --git a/src/core/lib/gpr/fork.h b/src/core/lib/gprpp/fork.h
similarity index 76%
rename from src/core/lib/gpr/fork.h
rename to src/core/lib/gprpp/fork.h
index bf5acc3292d..830bb6b5050 100644
--- a/src/core/lib/gpr/fork.h
+++ b/src/core/lib/gprpp/fork.h
@@ -26,14 +26,12 @@
 
 namespace grpc_core {
 
-namespace {
-  class ExecCtxState;
-  class ThreadState;
-}
-
 namespace internal {
+class ExecCtxState;
+class ThreadState;
+}  // namespace internal
 
-class ForkSupport {
+class Fork {
  public:
   static void GlobalInit();
   static void GlobalShutdown();
@@ -43,40 +41,39 @@ class ForkSupport {
 
   // Increment the count of active ExecCtxs.
   // Will block until a pending fork is complete if one is in progress.
-  void IncExecCtxCount();
+  static void IncExecCtxCount();
 
   // Decrement the count of active ExecCtxs
-  void DecExecCtxCount();
+  static void DecExecCtxCount();
 
   // Check if there is a single active ExecCtx
   // (the one used to invoke this function).  If there are more,
   // return false.  Otherwise, return true and block creation of
   // more ExecCtx s until AlloWExecCtx() is called
   //
-  bool BlockExecCtx();
-  void AllowExecCtx();
+  static bool BlockExecCtx();
+  static void AllowExecCtx();
 
   // Increment the count of active threads.
-  void IncThreadCount();
+  static void IncThreadCount();
 
   // Decrement the count of active threads.
-  void DecThreadCount();
+  static void DecThreadCount();
 
   // Await all core threads to be joined.
-  void AwaitThreads();
+  static void AwaitThreads();
 
   // Test only: overrides environment variables/compile flags
   // Must be called before grpc_init()
-  void Enable(bool enable);
+  static void Enable(bool enable);
 
  private:
-  static ExecCtxState* execCtxState_ = nullptr;
-  static ThreadState* threadState_ = nullptr;
-  static bool supportEnabled_ = false;
-  static int overrideEnabled_ = -1;
-}
-
-} // namespace internal
-} // namespace grpc_core
+  static internal::ExecCtxState* execCtxState_;
+  static internal::ThreadState* threadState_;
+  static bool supportEnabled_;
+  static int overrideEnabled_;
+};
+
+}  // namespace grpc_core
 
 #endif /* GRPC_CORE_LIB_GPR_FORK_H */
diff --git a/src/core/lib/gprpp/thd_posix.cc b/src/core/lib/gprpp/thd_posix.cc
index 1a20a0bbc34..533c07e7d88 100644
--- a/src/core/lib/gprpp/thd_posix.cc
+++ b/src/core/lib/gprpp/thd_posix.cc
@@ -32,8 +32,8 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "src/core/lib/gpr/fork.h"
 #include "src/core/lib/gpr/useful.h"
+#include "src/core/lib/gprpp/fork.h"
 #include "src/core/lib/gprpp/memory.h"
 
 namespace grpc_core {
@@ -63,7 +63,7 @@ class ThreadInternalsPosix
     info->body = thd_body;
     info->arg = arg;
     info->name = thd_name;
-    grpc_fork_inc_thd_count();
+    grpc_core::Fork::IncThreadCount();
 
     GPR_ASSERT(pthread_attr_init(&attr) == 0);
     GPR_ASSERT(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE) ==
@@ -98,7 +98,7 @@ class ThreadInternalsPosix
                           gpr_mu_unlock(&arg.thread->mu_);
 
                           (*arg.body)(arg.arg);
-                          grpc_fork_dec_thd_count();
+                          grpc_core::Fork::DecThreadCount();
                           return nullptr;
                         },
                         info) == 0);
@@ -108,7 +108,7 @@ class ThreadInternalsPosix
     if (!success) {
       /* don't use gpr_free, as this was allocated using malloc (see above) */
       free(info);
-      grpc_fork_dec_thd_count();
+      grpc_core::Fork::DecThreadCount();
     }
   };
 
diff --git a/src/core/lib/iomgr/exec_ctx.h b/src/core/lib/iomgr/exec_ctx.h
index b5b59621f9e..5eb4faaea37 100644
--- a/src/core/lib/iomgr/exec_ctx.h
+++ b/src/core/lib/iomgr/exec_ctx.h
@@ -25,8 +25,8 @@
 #include <grpc/support/cpu.h>
 #include <grpc/support/log.h>
 
-#include "src/core/lib/gpr/fork.h"
 #include "src/core/lib/gpr/tls.h"
+#include "src/core/lib/gprpp/fork.h"
 #include "src/core/lib/iomgr/closure.h"
 
 typedef gpr_atm grpc_millis;
@@ -78,13 +78,13 @@ class ExecCtx {
   /** Default Constructor */
 
   ExecCtx() : flags_(GRPC_EXEC_CTX_FLAG_IS_FINISHED) {
-    grpc_fork_inc_exec_ctx_count();
+    grpc_core::Fork::IncExecCtxCount();
     Set(this);
   }
 
   /** Parameterised Constructor */
   ExecCtx(uintptr_t fl) : flags_(fl) {
-    grpc_fork_inc_exec_ctx_count();
+    grpc_core::Fork::IncExecCtxCount();
     Set(this);
   }
 
@@ -93,7 +93,7 @@ class ExecCtx {
     flags_ |= GRPC_EXEC_CTX_FLAG_IS_FINISHED;
     Flush();
     Set(last_exec_ctx_);
-    grpc_fork_dec_exec_ctx_count();
+    grpc_core::Fork::DecExecCtxCount();
   }
 
   /** Disallow copy and assignment operators */
diff --git a/src/core/lib/iomgr/fork_posix.cc b/src/core/lib/iomgr/fork_posix.cc
index dd0f9f612f7..b37384b8db7 100644
--- a/src/core/lib/iomgr/fork_posix.cc
+++ b/src/core/lib/iomgr/fork_posix.cc
@@ -28,7 +28,7 @@
 #include <grpc/support/log.h>
 
 #include "src/core/lib/gpr/env.h"
-#include "src/core/lib/gpr/fork.h"
+#include "src/core/lib/gprpp/fork.h"
 #include "src/core/lib/gprpp/thd.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/executor.h"
@@ -52,13 +52,13 @@ void grpc_prefork() {
   if (!grpc_is_initialized()) {
     return;
   }
-  if (!grpc_fork_support_enabled()) {
+  if (!grpc_core::Fork::Enabled()) {
     gpr_log(GPR_ERROR,
             "Fork support not enabled; try running with the "
             "environment variable GRPC_ENABLE_FORK_SUPPORT=1");
     return;
   }
-  if (!grpc_fork_block_exec_ctx()) {
+  if (!grpc_core::Fork::BlockExecCtx()) {
     gpr_log(GPR_INFO,
             "Other threads are currently calling into gRPC, skipping fork() "
             "handlers");
@@ -67,13 +67,13 @@ void grpc_prefork() {
   grpc_timer_manager_set_threading(false);
   grpc_executor_set_threading(false);
   grpc_core::ExecCtx::Get()->Flush();
-  grpc_fork_await_thds();
+  grpc_core::Fork::AwaitThreads();
   skipped_handler = false;
 }
 
 void grpc_postfork_parent() {
   if (!skipped_handler) {
-    grpc_fork_allow_exec_ctx();
+    grpc_core::Fork::AllowExecCtx();
     grpc_core::ExecCtx exec_ctx;
     grpc_timer_manager_set_threading(true);
     grpc_executor_set_threading(true);
@@ -82,7 +82,7 @@ void grpc_postfork_parent() {
 
 void grpc_postfork_child() {
   if (!skipped_handler) {
-    grpc_fork_allow_exec_ctx();
+    grpc_core::Fork::AllowExecCtx();
     grpc_core::ExecCtx exec_ctx;
     grpc_timer_manager_set_threading(true);
     grpc_executor_set_threading(true);
@@ -90,7 +90,7 @@ void grpc_postfork_child() {
 }
 
 void grpc_fork_handlers_auto_register() {
-  if (grpc_fork_support_enabled() & !registered_handlers) {
+  if (grpc_core::Fork::Enabled() & !registered_handlers) {
 #ifdef GRPC_POSIX_FORK_ALLOW_PTHREAD_ATFORK
     pthread_atfork(grpc_prefork, grpc_postfork_parent, grpc_postfork_child);
     registered_handlers = true;
diff --git a/src/core/lib/surface/init.cc b/src/core/lib/surface/init.cc
index 285e6f7ddc7..8bbcef467ad 100644
--- a/src/core/lib/surface/init.cc
+++ b/src/core/lib/surface/init.cc
@@ -31,8 +31,7 @@
 #include "src/core/lib/channel/handshaker_registry.h"
 #include "src/core/lib/debug/stats.h"
 #include "src/core/lib/debug/trace.h"
-#include "src/core/lib/gpr/fork.h"
-#include "src/core/lib/gprpp/thd.h"
+#include "src/core/lib/gprpp/fork.h"
 #include "src/core/lib/http/parser.h"
 #include "src/core/lib/iomgr/call_combiner.h"
 #include "src/core/lib/iomgr/combiner.h"
@@ -120,7 +119,7 @@ void grpc_init(void) {
 
   gpr_mu_lock(&g_init_mu);
   if (++g_initializations == 1) {
-    grpc_fork_support_init();
+    grpc_core::Fork::GlobalInit();
     grpc_fork_handlers_auto_register();
     gpr_time_init();
     grpc_stats_init();
@@ -176,7 +175,7 @@ void grpc_shutdown(void) {
       grpc_handshaker_factory_registry_shutdown();
       grpc_slice_intern_shutdown();
       grpc_stats_shutdown();
-      grpc_fork_support_destroy();
+      grpc_core::Fork::GlobalShutdown();
     }
     grpc_core::ExecCtx::GlobalShutdown();
   }
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index dd3a8f963f8..c1654358a38 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -25,7 +25,6 @@ CORE_SOURCE_FILES = [
     'src/core/lib/gpr/env_linux.cc',
     'src/core/lib/gpr/env_posix.cc',
     'src/core/lib/gpr/env_windows.cc',
-    'src/core/lib/gpr/fork.cc',
     'src/core/lib/gpr/host_port.cc',
     'src/core/lib/gpr/log.cc',
     'src/core/lib/gpr/log_android.cc',
@@ -50,6 +49,7 @@ CORE_SOURCE_FILES = [
     'src/core/lib/gpr/tmpfile_posix.cc',
     'src/core/lib/gpr/tmpfile_windows.cc',
     'src/core/lib/gpr/wrap_memcpy.cc',
+    'src/core/lib/gprpp/fork.cc',
     'src/core/lib/gprpp/thd_posix.cc',
     'src/core/lib/gprpp/thd_windows.cc',
     'src/core/lib/profiling/basic_timers.cc',
diff --git a/test/core/gpr/fork_test.cc b/test/core/gprpp/fork_test.cc
similarity index 60%
rename from test/core/gpr/fork_test.cc
rename to test/core/gprpp/fork_test.cc
index bc388c4a77f..c4a8a4e5f5b 100644
--- a/test/core/gpr/fork_test.cc
+++ b/test/core/gprpp/fork_test.cc
@@ -16,30 +16,30 @@
  *
  */
 
-#include "src/core/lib/gpr/fork.h"
+#include "src/core/lib/gprpp/fork.h"
 
 #include "src/core/lib/gprpp/thd.h"
 #include "test/core/util/test_config.h"
 
 static void test_init() {
-  GPR_ASSERT(!grpc_fork_support_enabled());
+  GPR_ASSERT(!grpc_core::Fork::Enabled());
 
   // Default fork support (disabled)
-  grpc_fork_support_init();
-  GPR_ASSERT(!grpc_fork_support_enabled());
-  grpc_fork_support_destroy();
+  grpc_core::Fork::GlobalInit();
+  GPR_ASSERT(!grpc_core::Fork::Enabled());
+  grpc_core::Fork::GlobalShutdown();
 
   // Explicitly disabled fork support
-  grpc_enable_fork_support(false);
-  grpc_fork_support_init();
-  GPR_ASSERT(!grpc_fork_support_enabled());
-  grpc_fork_support_destroy();
+  grpc_core::Fork::Enable(false);
+  grpc_core::Fork::GlobalInit();
+  GPR_ASSERT(!grpc_core::Fork::Enabled());
+  grpc_core::Fork::GlobalShutdown();
 
   // Explicitly enabled fork support
-  grpc_enable_fork_support(true);
-  grpc_fork_support_init();
-  GPR_ASSERT(grpc_fork_support_enabled());
-  grpc_fork_support_destroy();
+  grpc_core::Fork::Enable(true);
+  grpc_core::Fork::GlobalInit();
+  GPR_ASSERT(grpc_core::Fork::Enabled());
+  grpc_core::Fork::GlobalShutdown();
 }
 
 #define THREAD_DELAY_MS 3000
@@ -54,13 +54,13 @@ static void sleeping_thd(void* arg) {
 
 static void test_thd_count() {
   // Test no active threads
-  grpc_enable_fork_support(true);
-  grpc_fork_support_init();
-  grpc_fork_await_thds();
-  grpc_fork_support_destroy();
+  grpc_core::Fork::Enable(true);
+  grpc_core::Fork::GlobalInit();
+  grpc_core::Fork::AwaitThreads();
+  grpc_core::Fork::GlobalShutdown();
 
-  grpc_enable_fork_support(true);
-  grpc_fork_support_init();
+  grpc_core::Fork::Enable(true);
+  grpc_core::Fork::GlobalInit();
   grpc_core::Thread thds[CONCURRENT_TEST_THREADS];
   gpr_timespec est_end_time =
       gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
@@ -74,56 +74,56 @@ static void test_thd_count() {
         grpc_core::Thread("grpc_fork_test", sleeping_thd, (void*)sleep_time_ms);
     thds[i].Start();
   }
-  grpc_fork_await_thds();
+  grpc_core::Fork::AwaitThreads();
   gpr_timespec end_time = gpr_now(GPR_CLOCK_REALTIME);
   for (auto& thd : thds) {
     thd.Join();
   }
   GPR_ASSERT(gpr_time_similar(end_time, est_end_time, tolerance));
-  grpc_fork_support_destroy();
+  grpc_core::Fork::GlobalShutdown();
 }
 
 static void exec_ctx_thread(void* arg) {
   bool* exec_ctx_created = (bool*)arg;
-  grpc_fork_inc_exec_ctx_count();
+  grpc_core::Fork::IncExecCtxCount();
   *exec_ctx_created = true;
 }
 
 static void test_exec_count() {
-  grpc_fork_inc_exec_ctx_count();
-  grpc_enable_fork_support(true);
-  grpc_fork_support_init();
-
-  grpc_fork_inc_exec_ctx_count();
-  GPR_ASSERT(grpc_fork_block_exec_ctx());
-  grpc_fork_dec_exec_ctx_count();
-  grpc_fork_allow_exec_ctx();
-
-  grpc_fork_inc_exec_ctx_count();
-  grpc_fork_inc_exec_ctx_count();
-  GPR_ASSERT(!grpc_fork_block_exec_ctx());
-  grpc_fork_dec_exec_ctx_count();
-  grpc_fork_dec_exec_ctx_count();
-
-  grpc_fork_inc_exec_ctx_count();
-  GPR_ASSERT(grpc_fork_block_exec_ctx());
-  grpc_fork_dec_exec_ctx_count();
-  grpc_fork_allow_exec_ctx();
-
-  // Test that block_exec_ctx() blocks grpc_fork_inc_exec_ctx_count
+  grpc_core::Fork::IncExecCtxCount();
+  grpc_core::Fork::Enable(true);
+  grpc_core::Fork::GlobalInit();
+
+  grpc_core::Fork::IncExecCtxCount();
+  GPR_ASSERT(grpc_core::Fork::BlockExecCtx());
+  grpc_core::Fork::DecExecCtxCount();
+  grpc_core::Fork::AllowExecCtx();
+
+  grpc_core::Fork::IncExecCtxCount();
+  grpc_core::Fork::IncExecCtxCount();
+  GPR_ASSERT(!grpc_core::Fork::BlockExecCtx());
+  grpc_core::Fork::DecExecCtxCount();
+  grpc_core::Fork::DecExecCtxCount();
+
+  grpc_core::Fork::IncExecCtxCount();
+  GPR_ASSERT(grpc_core::Fork::BlockExecCtx());
+  grpc_core::Fork::DecExecCtxCount();
+  grpc_core::Fork::AllowExecCtx();
+
+  // Test that block_exec_ctx() blocks grpc_core::Fork::IncExecCtxCount
   bool exec_ctx_created = false;
   grpc_core::Thread thd =
       grpc_core::Thread("grpc_fork_test", exec_ctx_thread, &exec_ctx_created);
-  grpc_fork_inc_exec_ctx_count();
-  GPR_ASSERT(grpc_fork_block_exec_ctx());
-  grpc_fork_dec_exec_ctx_count();
+  grpc_core::Fork::IncExecCtxCount();
+  GPR_ASSERT(grpc_core::Fork::BlockExecCtx());
+  grpc_core::Fork::DecExecCtxCount();
   thd.Start();
   gpr_sleep_until(gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
                                gpr_time_from_seconds(1, GPR_TIMESPAN)));
   GPR_ASSERT(!exec_ctx_created);
-  grpc_fork_allow_exec_ctx();
+  grpc_core::Fork::AllowExecCtx();
   thd.Join();  // This ensure that the call got un-blocked
-  grpc_fork_support_destroy();
+  grpc_core::Fork::GlobalShutdown();
 }
 
 int main(int argc, char* argv[]) {
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index ff5abc679d8..095c3c3dcb3 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -1023,7 +1023,6 @@ src/core/lib/debug/stats_data.h \
 src/core/lib/debug/trace.h \
 src/core/lib/gpr/arena.h \
 src/core/lib/gpr/env.h \
-src/core/lib/gpr/fork.h \
 src/core/lib/gpr/host_port.h \
 src/core/lib/gpr/mpscq.h \
 src/core/lib/gpr/murmur_hash.h \
@@ -1042,6 +1041,7 @@ src/core/lib/gprpp/atomic.h \
 src/core/lib/gprpp/atomic_with_atm.h \
 src/core/lib/gprpp/atomic_with_std.h \
 src/core/lib/gprpp/debug_location.h \
+src/core/lib/gprpp/fork.h \
 src/core/lib/gprpp/inlined_vector.h \
 src/core/lib/gprpp/manual_constructor.h \
 src/core/lib/gprpp/memory.h \
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index e7e9e04979e..688ec34abf1 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -1074,8 +1074,6 @@ src/core/lib/gpr/env.h \
 src/core/lib/gpr/env_linux.cc \
 src/core/lib/gpr/env_posix.cc \
 src/core/lib/gpr/env_windows.cc \
-src/core/lib/gpr/fork.cc \
-src/core/lib/gpr/fork.h \
 src/core/lib/gpr/host_port.cc \
 src/core/lib/gpr/host_port.h \
 src/core/lib/gpr/log.cc \
@@ -1119,6 +1117,8 @@ src/core/lib/gprpp/atomic.h \
 src/core/lib/gprpp/atomic_with_atm.h \
 src/core/lib/gprpp/atomic_with_std.h \
 src/core/lib/gprpp/debug_location.h \
+src/core/lib/gprpp/fork.cc \
+src/core/lib/gprpp/fork.h \
 src/core/lib/gprpp/inlined_vector.h \
 src/core/lib/gprpp/manual_constructor.h \
 src/core/lib/gprpp/memory.h \
diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json
index 0ddecffa5f6..f609f8de7cf 100644
--- a/tools/run_tests/generated/sources_and_headers.json
+++ b/tools/run_tests/generated/sources_and_headers.json
@@ -612,7 +612,7 @@
     "language": "c", 
     "name": "fork_test", 
     "src": [
-      "test/core/gpr/fork_test.cc"
+      "test/core/gprpp/fork_test.cc"
     ], 
     "third_party": false, 
     "type": "target"
@@ -8779,7 +8779,6 @@
       "src/core/lib/gpr/env_linux.cc", 
       "src/core/lib/gpr/env_posix.cc", 
       "src/core/lib/gpr/env_windows.cc", 
-      "src/core/lib/gpr/fork.cc", 
       "src/core/lib/gpr/host_port.cc", 
       "src/core/lib/gpr/log.cc", 
       "src/core/lib/gpr/log_android.cc", 
@@ -8804,6 +8803,7 @@
       "src/core/lib/gpr/tmpfile_posix.cc", 
       "src/core/lib/gpr/tmpfile_windows.cc", 
       "src/core/lib/gpr/wrap_memcpy.cc", 
+      "src/core/lib/gprpp/fork.cc", 
       "src/core/lib/gprpp/thd_posix.cc", 
       "src/core/lib/gprpp/thd_windows.cc", 
       "src/core/lib/profiling/basic_timers.cc", 
@@ -8836,7 +8836,6 @@
       "include/grpc/support/time.h", 
       "src/core/lib/gpr/arena.h", 
       "src/core/lib/gpr/env.h", 
-      "src/core/lib/gpr/fork.h", 
       "src/core/lib/gpr/host_port.h", 
       "src/core/lib/gpr/mpscq.h", 
       "src/core/lib/gpr/murmur_hash.h", 
@@ -8854,6 +8853,7 @@
       "src/core/lib/gprpp/atomic.h", 
       "src/core/lib/gprpp/atomic_with_atm.h", 
       "src/core/lib/gprpp/atomic_with_std.h", 
+      "src/core/lib/gprpp/fork.h", 
       "src/core/lib/gprpp/manual_constructor.h", 
       "src/core/lib/gprpp/memory.h", 
       "src/core/lib/gprpp/thd.h", 
@@ -8882,7 +8882,6 @@
       "include/grpc/support/time.h", 
       "src/core/lib/gpr/arena.h", 
       "src/core/lib/gpr/env.h", 
-      "src/core/lib/gpr/fork.h", 
       "src/core/lib/gpr/host_port.h", 
       "src/core/lib/gpr/mpscq.h", 
       "src/core/lib/gpr/murmur_hash.h", 
@@ -8900,6 +8899,7 @@
       "src/core/lib/gprpp/atomic.h", 
       "src/core/lib/gprpp/atomic_with_atm.h", 
       "src/core/lib/gprpp/atomic_with_std.h", 
+      "src/core/lib/gprpp/fork.h", 
       "src/core/lib/gprpp/manual_constructor.h", 
       "src/core/lib/gprpp/memory.h", 
       "src/core/lib/gprpp/thd.h", 

From 3cced83d2cace449485498537f5ec01a2432cdce Mon Sep 17 00:00:00 2001
From: kpayson64 <kpayson@google.com>
Date: Fri, 11 May 2018 10:51:46 -0700
Subject: [PATCH 3/6] Test failure fixes

---
 src/core/lib/gprpp/fork.cc | 24 ++++++++++++++++++++----
 src/core/lib/gprpp/fork.h  |  6 +++---
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/src/core/lib/gprpp/fork.cc b/src/core/lib/gprpp/fork.cc
index 78f6a2fa0d2..ddc95f26eb2 100644
--- a/src/core/lib/gprpp/fork.cc
+++ b/src/core/lib/gprpp/fork.cc
@@ -225,12 +225,28 @@ bool Fork::BlockExecCtx() {
   return false;
 }
 
-void Fork::AllowExecCtx() { execCtxState_->AllowExecCtx(); }
+void Fork::AllowExecCtx() {
+  if (supportEnabled_) {
+    execCtxState_->AllowExecCtx();
+  }
+}
 
-void Fork::IncThreadCount() { threadState_->IncThreadCount(); }
+void Fork::IncThreadCount() {
+  if (supportEnabled_) {
+    threadState_->IncThreadCount();
+  }
+}
 
-void Fork::DecThreadCount() { threadState_->DecThreadCount(); }
-void Fork::AwaitThreads() { threadState_->AwaitThreads(); }
+void Fork::DecThreadCount() {
+  if (supportEnabled_) {
+    threadState_->DecThreadCount();
+  }
+}
+void Fork::AwaitThreads() {
+  if (supportEnabled_) {
+    threadState_->AwaitThreads();
+  }
+}
 
 internal::ExecCtxState* Fork::execCtxState_ = nullptr;
 internal::ThreadState* Fork::threadState_ = nullptr;
diff --git a/src/core/lib/gprpp/fork.h b/src/core/lib/gprpp/fork.h
index 830bb6b5050..60ed74b1fbb 100644
--- a/src/core/lib/gprpp/fork.h
+++ b/src/core/lib/gprpp/fork.h
@@ -16,8 +16,8 @@
  *
  */
 
-#ifndef GRPC_CORE_LIB_GPR_FORK_H
-#define GRPC_CORE_LIB_GPR_FORK_H
+#ifndef GRPC_CORE_LIB_GPRPP_FORK_H
+#define GRPC_CORE_LIB_GPRPP_FORK_H
 
 /*
  * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK
@@ -76,4 +76,4 @@ class Fork {
 
 }  // namespace grpc_core
 
-#endif /* GRPC_CORE_LIB_GPR_FORK_H */
+#endif /* GRPC_CORE_LIB_GPRPP_FORK_H */

From ec445cc2bb270ed4acb1c710c3533fca14a50019 Mon Sep 17 00:00:00 2001
From: kpayson64 <kpayson@google.com>
Date: Fri, 11 May 2018 11:25:55 -0700
Subject: [PATCH 4/6] BUILD fixes

---
 test/core/gpr/BUILD   | 10 ----------
 test/core/gprpp/BUILD | 10 ++++++++++
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/test/core/gpr/BUILD b/test/core/gpr/BUILD
index 2aeccc0a0f7..5308ea09348 100644
--- a/test/core/gpr/BUILD
+++ b/test/core/gpr/BUILD
@@ -58,16 +58,6 @@ grpc_cc_test(
     ],
 )
 
-grpc_cc_test(
-    name = "fork_test",
-    srcs = ["fork_test.cc"],
-    language = "C++",
-    deps = [
-        "//:gpr",
-        "//test/core/util:gpr_test_util",
-    ],
-)
-
 grpc_cc_test(
     name = "host_port_test",
     srcs = ["host_port_test.cc"],
diff --git a/test/core/gprpp/BUILD b/test/core/gprpp/BUILD
index a8a57395521..e7232d9df81 100644
--- a/test/core/gprpp/BUILD
+++ b/test/core/gprpp/BUILD
@@ -18,6 +18,16 @@ licenses(["notice"])  # Apache v2
 
 grpc_package(name = "test/core/gprpp")
 
+grpc_cc_test(
+    name = "fork_test",
+    srcs = ["fork_test.cc"],
+    language = "C++",
+    deps = [
+        "//:gpr",
+        "//test/core/util:gpr_test_util",
+    ],
+)
+
 grpc_cc_test(
     name = "manual_constructor_test",
     srcs = ["manual_constructor_test.cc"],

From c934a2e25d403c21aeef9bacf37260bea9e0ca57 Mon Sep 17 00:00:00 2001
From: kpayson64 <kpayson@google.com>
Date: Fri, 11 May 2018 12:22:47 -0700
Subject: [PATCH 5/6] Regenerate projects

---
 CMakeLists.txt               | 1 +
 test/core/gprpp/fork_test.cc | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d1933c4b046..f53f4e384c2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6434,6 +6434,7 @@ target_include_directories(fork_test
   PRIVATE ${_gRPC_BENCHMARK_INCLUDE_DIR}
   PRIVATE ${_gRPC_CARES_INCLUDE_DIR}
   PRIVATE ${_gRPC_GFLAGS_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ADDRESS_SORTING_INCLUDE_DIR}
 )
 
 target_link_libraries(fork_test
diff --git a/test/core/gprpp/fork_test.cc b/test/core/gprpp/fork_test.cc
index c4a8a4e5f5b..05820eb8855 100644
--- a/test/core/gprpp/fork_test.cc
+++ b/test/core/gprpp/fork_test.cc
@@ -90,7 +90,6 @@ static void exec_ctx_thread(void* arg) {
 }
 
 static void test_exec_count() {
-  grpc_core::Fork::IncExecCtxCount();
   grpc_core::Fork::Enable(true);
   grpc_core::Fork::GlobalInit();
 

From 40c93b6387571121979428035f2376e1e8f010d6 Mon Sep 17 00:00:00 2001
From: kpayson64 <kpayson@google.com>
Date: Fri, 11 May 2018 13:04:30 -0700
Subject: [PATCH 6/6] Review changes

---
 src/core/lib/gprpp/fork.cc | 58 ++++++++++++++++++++------------------
 src/core/lib/gprpp/fork.h  |  2 +-
 2 files changed, 32 insertions(+), 28 deletions(-)

diff --git a/src/core/lib/gprpp/fork.cc b/src/core/lib/gprpp/fork.cc
index ddc95f26eb2..f6d9a87d2c1 100644
--- a/src/core/lib/gprpp/fork.cc
+++ b/src/core/lib/gprpp/fork.cc
@@ -56,7 +56,7 @@ class ExecCtxState {
   }
 
   void IncExecCtxCount() {
-    intptr_t count = static_cast<intptr_t>(gpr_atm_no_barrier_load(&count_));
+    gpr_atm count = gpr_atm_no_barrier_load(&count_);
     while (true) {
       if (count <= BLOCKED(1)) {
         // This only occurs if we are trying to fork.  Wait until the fork()
@@ -80,7 +80,9 @@ class ExecCtxState {
   bool BlockExecCtx() {
     // Assumes there is an active ExecCtx when this function is called
     if (gpr_atm_no_barrier_cas(&count_, UNBLOCKED(1), BLOCKED(1))) {
+      gpr_mu_lock(&mu_);
       fork_complete_ = false;
+      gpr_mu_unlock(&mu_);
       return true;
     }
     return false;
@@ -155,38 +157,37 @@ class ThreadState {
 }  // namespace
 
 void Fork::GlobalInit() {
+  if (!overrideEnabled_) {
 #ifdef GRPC_ENABLE_FORK_SUPPORT
-  supportEnabled_ = true;
+    supportEnabled_ = true;
 #else
-  supportEnabled_ = false;
+    supportEnabled_ = false;
 #endif
-  bool env_var_set = false;
-  char* env = gpr_getenv("GRPC_ENABLE_FORK_SUPPORT");
-  if (env != nullptr) {
-    static const char* truthy[] = {"yes",  "Yes",  "YES", "true",
-                                   "True", "TRUE", "1"};
-    static const char* falsey[] = {"no",    "No",    "NO", "false",
-                                   "False", "FALSE", "0"};
-    for (size_t i = 0; i < GPR_ARRAY_SIZE(truthy); i++) {
-      if (0 == strcmp(env, truthy[i])) {
-        supportEnabled_ = true;
-        env_var_set = true;
-        break;
-      }
-    }
-    if (!env_var_set) {
-      for (size_t i = 0; i < GPR_ARRAY_SIZE(falsey); i++) {
-        if (0 == strcmp(env, falsey[i])) {
-          supportEnabled_ = false;
+    bool env_var_set = false;
+    char* env = gpr_getenv("GRPC_ENABLE_FORK_SUPPORT");
+    if (env != nullptr) {
+      static const char* truthy[] = {"yes",  "Yes",  "YES", "true",
+                                     "True", "TRUE", "1"};
+      static const char* falsey[] = {"no",    "No",    "NO", "false",
+                                     "False", "FALSE", "0"};
+      for (size_t i = 0; i < GPR_ARRAY_SIZE(truthy); i++) {
+        if (0 == strcmp(env, truthy[i])) {
+          supportEnabled_ = true;
           env_var_set = true;
           break;
         }
       }
+      if (!env_var_set) {
+        for (size_t i = 0; i < GPR_ARRAY_SIZE(falsey); i++) {
+          if (0 == strcmp(env, falsey[i])) {
+            supportEnabled_ = false;
+            env_var_set = true;
+            break;
+          }
+        }
+      }
+      gpr_free(env);
     }
-    gpr_free(env);
-  }
-  if (overrideEnabled_ != -1) {
-    supportEnabled_ = (overrideEnabled_ == 1);
   }
   if (supportEnabled_) {
     execCtxState_ = grpc_core::New<internal::ExecCtxState>();
@@ -204,7 +205,10 @@ void Fork::GlobalShutdown() {
 bool Fork::Enabled() { return supportEnabled_; }
 
 // Testing Only
-void Fork::Enable(bool enable) { overrideEnabled_ = enable ? 1 : 0; }
+void Fork::Enable(bool enable) {
+  overrideEnabled_ = true;
+  supportEnabled_ = enable;
+}
 
 void Fork::IncExecCtxCount() {
   if (supportEnabled_) {
@@ -251,6 +255,6 @@ void Fork::AwaitThreads() {
 internal::ExecCtxState* Fork::execCtxState_ = nullptr;
 internal::ThreadState* Fork::threadState_ = nullptr;
 bool Fork::supportEnabled_ = false;
-int Fork::overrideEnabled_ = -1;
+bool Fork::overrideEnabled_ = false;
 
 }  // namespace grpc_core
diff --git a/src/core/lib/gprpp/fork.h b/src/core/lib/gprpp/fork.h
index 60ed74b1fbb..123e22c4c6f 100644
--- a/src/core/lib/gprpp/fork.h
+++ b/src/core/lib/gprpp/fork.h
@@ -71,7 +71,7 @@ class Fork {
   static internal::ExecCtxState* execCtxState_;
   static internal::ThreadState* threadState_;
   static bool supportEnabled_;
-  static int overrideEnabled_;
+  static bool overrideEnabled_;
 };
 
 }  // namespace grpc_core