Merge branch 'v1.7.x' of https://github.com/grpc/grpc

10 files changed, 324 insertions, 2 deletions

diff --git a/src/core/lib/iomgr/fork_posix.cc b/src/core/lib/iomgr/fork_posix.cc
new file mode 100644
index 0000000000..a55b3a349a
--- /dev/null
+++ b/src/core/lib/iomgr/fork_posix.cc
@@ -0,0 +1,88 @@
+/*
+ *
+ * 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/iomgr/port.h"
+
+#ifdef GRPC_POSIX_FORK
+
+#include <string.h>
+
+#include <grpc/fork.h>
+#include <grpc/support/log.h>
+#include <grpc/support/thd.h>
+#include <grpc/support/useful.h>
+
+#include "src/core/lib/iomgr/ev_posix.h"
+#include "src/core/lib/iomgr/executor.h"
+#include "src/core/lib/iomgr/timer_manager.h"
+#include "src/core/lib/iomgr/wakeup_fd_posix.h"
+#include "src/core/lib/support/env.h"
+#include "src/core/lib/support/fork.h"
+#include "src/core/lib/support/thd_internal.h"
+#include "src/core/lib/surface/init.h"
+
+/*
+ * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK
+ *       AROUND VERY SPECIFIC USE CASES.
+ */
+
+void grpc_prefork() {
+  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_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    grpc_timer_manager_set_threading(false);
+    grpc_executor_set_threading(&exec_ctx, false);
+    grpc_exec_ctx_finish(&exec_ctx);
+    if (!gpr_await_threads(
+            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!");
+    }
+  }
+}
+
+void grpc_postfork_parent() {
+  if (grpc_is_initialized()) {
+    grpc_timer_manager_set_threading(true);
+    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    grpc_executor_set_threading(&exec_ctx, true);
+    grpc_exec_ctx_finish(&exec_ctx);
+  }
+}
+
+void grpc_postfork_child() {
+  if (grpc_is_initialized()) {
+    grpc_timer_manager_set_threading(true);
+    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    grpc_executor_set_threading(&exec_ctx, true);
+    grpc_exec_ctx_finish(&exec_ctx);
+  }
+}
+
+void grpc_fork_handlers_auto_register() {
+  if (grpc_fork_support_enabled()) {
+    pthread_atfork(grpc_prefork, grpc_postfork_parent, grpc_postfork_child);
+  }
+}
+
+#endif  // GRPC_POSIX_FORK
diff --git a/src/core/lib/iomgr/fork_windows.cc b/src/core/lib/iomgr/fork_windows.cc
new file mode 100644
index 0000000000..f9986f33c7
--- /dev/null
+++ b/src/core/lib/iomgr/fork_windows.cc
@@ -0,0 +1,39 @@
+/*
+ *
+ * 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/iomgr/port.h"
+
+#ifndef GRPC_POSIX_FORK
+
+#include <grpc/fork.h>
+#include <grpc/support/log.h>
+
+/*
+ * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK
+ *       AROUND VERY SPECIFIC USE CASES.
+ */
+
+void grpc_prefork() { gpr_log(GPR_ERROR, "Forking not supported on Windows"); }
+
+void grpc_postfork_parent() {}
+
+void grpc_postfork_child() {}
+
+void grpc_fork_handlers_auto_register() {}
+
+#endif  // GRPC_POSIX_FORK
diff --git a/src/core/lib/iomgr/port.h b/src/core/lib/iomgr/port.h
index 1cc6d98491..9fae8c0052 100644
--- a/src/core/lib/iomgr/port.h
+++ b/src/core/lib/iomgr/port.h
@@ -30,6 +30,7 @@
 #define GRPC_HAVE_IP_PKTINFO 1
 #define GRPC_HAVE_MSG_NOSIGNAL 1
 #define GRPC_HAVE_UNIX_SOCKET 1
+#define GRPC_POSIX_FORK 1
 #define GRPC_POSIX_NO_SPECIAL_WAKEUP_FD 1
 #define GRPC_POSIX_SOCKET 1
 #define GRPC_POSIX_SOCKETADDR 1
@@ -59,6 +60,7 @@
 #define GRPC_HAVE_MSG_NOSIGNAL 1
 #define GRPC_HAVE_UNIX_SOCKET 1
 #define GRPC_LINUX_MULTIPOLL_WITH_EPOLL 1
+#define GRPC_POSIX_FORK 1
 #define GRPC_POSIX_HOST_NAME_MAX 1
 #define GRPC_POSIX_SOCKET 1
 #define GRPC_POSIX_SOCKETADDR 1
@@ -90,6 +92,7 @@
 #define GRPC_HAVE_SO_NOSIGPIPE 1
 #define GRPC_HAVE_UNIX_SOCKET 1
 #define GRPC_MSG_IOVLEN_TYPE int
+#define GRPC_POSIX_FORK 1
 #define GRPC_POSIX_NO_SPECIAL_WAKEUP_FD 1
 #define GRPC_POSIX_SOCKET 1
 #define GRPC_POSIX_SOCKETADDR 1
@@ -103,6 +106,7 @@
 #define GRPC_HAVE_IPV6_RECVPKTINFO 1
 #define GRPC_HAVE_SO_NOSIGPIPE 1
 #define GRPC_HAVE_UNIX_SOCKET 1
+#define GRPC_POSIX_FORK 1
 #define GRPC_POSIX_NO_SPECIAL_WAKEUP_FD 1
 #define GRPC_POSIX_SOCKET 1
 #define GRPC_POSIX_SOCKETADDR 1
diff --git a/src/core/lib/support/fork.cc b/src/core/lib/support/fork.cc
new file mode 100644
index 0000000000..2f29af899d
--- /dev/null
+++ b/src/core/lib/support/fork.cc
@@ -0,0 +1,62 @@
+/*
+ *
+ * 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/support/fork.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/useful.h>
+
+#include "src/core/lib/support/env.h"
+
+/*
+ * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK
+ *       AROUND VERY SPECIFIC USE CASES.
+ */
+
+static int override_fork_support_enabled = -1;
+static int fork_support_enabled;
+
+void grpc_fork_support_init() {
+#ifdef GRPC_ENABLE_FORK_SUPPORT
+  fork_support_enabled = 1;
+#else
+  fork_support_enabled = 0;
+  char *env = gpr_getenv("GRPC_ENABLE_FORK_SUPPORT");
+  if (env != NULL) {
+    static const char *truthy[] = {"yes",  "Yes",  "YES", "true",
+                                   "True", "TRUE", "1"};
+    for (size_t i = 0; i < GPR_ARRAY_SIZE(truthy); i++) {
+      if (0 == strcmp(env, truthy[i])) {
+        fork_support_enabled = 1;
+      }
+    }
+    gpr_free(env);
+  }
+#endif
+  if (override_fork_support_enabled != -1) {
+    fork_support_enabled = override_fork_support_enabled;
+  }
+}
+
+int grpc_fork_support_enabled() { return fork_support_enabled; }
+
+void grpc_enable_fork_support(int enable) {
+  override_fork_support_enabled = enable;
+}
diff --git a/src/core/lib/support/fork.h b/src/core/lib/support/fork.h
new file mode 100644
index 0000000000..215d4214a6
--- /dev/null
+++ b/src/core/lib/support/fork.h
@@ -0,0 +1,35 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SUPPORT_FORK_H
+#define GRPC_CORE_LIB_SUPPORT_FORK_H
+
+/*
+ * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK
+ *       AROUND VERY SPECIFIC USE CASES.
+ */
+
+void grpc_fork_support_init(void);
+
+int grpc_fork_support_enabled(void);
+
+// Test only:  Must be called before grpc_init(), and overrides
+// environment variables/compile flags
+void grpc_enable_fork_support(int enable);
+
+#endif /* GRPC_CORE_LIB_SUPPORT_FORK_H */
diff --git a/src/core/lib/support/thd_internal.h b/src/core/lib/support/thd_internal.h
new file mode 100644
index 0000000000..38bffc847d
--- /dev/null
+++ b/src/core/lib/support/thd_internal.h
@@ -0,0 +1,30 @@
+/*
+ *
+ * Copyright 2015 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.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SUPPORT_THD_INTERNAL_H
+#define GRPC_CORE_LIB_SUPPORT_THD_INTERNAL_H
+
+#include <grpc/support/time.h>
+
+/* Internal interfaces between modules within the gpr support library.  */
+void gpr_thd_init();
+
+/* Wait for all outstanding threads to finish, up to deadline */
+int gpr_await_threads(gpr_timespec deadline);
+
+#endif /* GRPC_CORE_LIB_SUPPORT_THD_INTERNAL_H */
diff --git a/src/core/lib/support/thd_posix.cc b/src/core/lib/support/thd_posix.cc
index 02e3846be1..c2a4f4198f 100644
--- a/src/core/lib/support/thd_posix.cc
+++ b/src/core/lib/support/thd_posix.cc
@@ -24,22 +24,34 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/sync.h>
 #include <grpc/support/thd.h>
 #include <grpc/support/useful.h>
 #include <pthread.h>
 #include <stdlib.h>
 #include <string.h>
 
+#include "src/core/lib/support/fork.h"
+
+static gpr_mu g_mu;
+static gpr_cv g_cv;
+static int g_thread_count;
+static int g_awaiting_threads;
+
 struct thd_arg {
   void (*body)(void* arg); /* body of a thread */
   void* arg;               /* argument to a thread */
 };
 
+static void inc_thd_count();
+static void dec_thd_count();
+
 /* Body of every thread started via gpr_thd_new. */
 static void* thread_body(void* v) {
   struct thd_arg a = *(struct thd_arg*)v;
   free(v);
   (*a.body)(a.arg);
+  dec_thd_count();
   return nullptr;
 }
 
@@ -54,6 +66,7 @@ int gpr_thd_new(gpr_thd_id* t, void (*thd_body)(void* arg), void* arg,
   GPR_ASSERT(a != nullptr);
   a->body = thd_body;
   a->arg = arg;
+  inc_thd_count();
 
   GPR_ASSERT(pthread_attr_init(&attr) == 0);
   if (gpr_thd_options_is_detached(options)) {
@@ -68,6 +81,7 @@ int gpr_thd_new(gpr_thd_id* t, void (*thd_body)(void* arg), void* arg,
   if (!thread_started) {
     /* don't use gpr_free, as this was allocated using malloc (see above) */
     free(a);
+    dec_thd_count();
   }
   *t = (gpr_thd_id)p;
   return thread_started;
@@ -77,4 +91,46 @@ gpr_thd_id gpr_thd_currentid(void) { return (gpr_thd_id)pthread_self(); }
 
 void gpr_thd_join(gpr_thd_id t) { pthread_join((pthread_t)t, nullptr); }
 
+/*****************************************
+ * 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);
+  }
+}
+
+void gpr_thd_init() {
+  gpr_mu_init(&g_mu);
+  gpr_cv_init(&g_cv);
+  g_thread_count = 0;
+  g_awaiting_threads = 0;
+}
+
+int gpr_await_threads(gpr_timespec deadline) {
+  gpr_mu_lock(&g_mu);
+  g_awaiting_threads = 1;
+  int res = 0;
+  if (g_thread_count > 0) {
+    res = gpr_cv_wait(&g_cv, &g_mu, deadline);
+  }
+  g_awaiting_threads = 0;
+  gpr_mu_unlock(&g_mu);
+  return res == 0;
+}
+
 #endif /* GPR_POSIX_SYNC */
diff --git a/src/core/lib/support/thd_windows.cc b/src/core/lib/support/thd_windows.cc
index 5bda7f440c..0875c2f03e 100644
--- a/src/core/lib/support/thd_windows.cc
+++ b/src/core/lib/support/thd_windows.cc
@@ -50,6 +50,8 @@ static void destroy_thread(struct thd_info* t) {
   gpr_free(t);
 }
 
+void gpr_thd_init(void) {}
+
 /* Body of every thread started via gpr_thd_new. */
 static DWORD WINAPI thread_body(void* v) {
   g_thd_info = (struct thd_info*)v;
diff --git a/src/core/lib/surface/init.cc b/src/core/lib/surface/init.cc
index c6d2f0a192..8ee1383fb8 100644
--- a/src/core/lib/surface/init.cc
+++ b/src/core/lib/surface/init.cc
@@ -21,6 +21,7 @@
 #include <limits.h>
 #include <memory.h>
 
+#include <grpc/fork.h>
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
@@ -39,6 +40,8 @@
 #include "src/core/lib/iomgr/timer_manager.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/support/fork.h"
+#include "src/core/lib/support/thd_internal.h"
 #include "src/core/lib/surface/alarm_internal.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/call.h"
@@ -62,10 +65,12 @@ 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_exec_ctx* exec_ctx,
@@ -122,6 +127,7 @@ void grpc_init(void) {
   gpr_mu_lock(&g_init_mu);
   if (++g_initializations == 1) {
     gpr_time_init();
+    gpr_thd_init();
     grpc_stats_init();
     grpc_slice_intern_init();
     grpc_mdctx_global_init();
diff --git a/src/core/lib/surface/version.cc b/src/core/lib/surface/version.cc
index f4feadc640..5c06c66d0c 100644
--- a/src/core/lib/surface/version.cc
+++ b/src/core/lib/surface/version.cc
@@ -21,6 +21,6 @@
 
 #include <grpc/grpc.h>
 
-const char* grpc_version_string(void) { return "5.0.0-dev"; }
+const char* grpc_version_string(void) { return "5.0.0"; }
 
-const char* grpc_g_stands_for(void) { return "generous"; }
+const char* grpc_g_stands_for(void) { return "gambit"; }