Merge pull request #12928 from kpayson64/forking_take_2

Add thread pool reset on fork with FORKING_SUPPORT_ENABLED

BUILD

@@ -476,6 +476,7 @@ grpc_cc_library(
         "src/core/lib/support/env_linux.c",
         "src/core/lib/support/env_posix.c",
         "src/core/lib/support/env_windows.c",
+        "src/core/lib/support/fork.c",
         "src/core/lib/support/histogram.c",
         "src/core/lib/support/host_port.c",
         "src/core/lib/support/log.c",
@@ -517,6 +518,7 @@ grpc_cc_library(
         "src/core/lib/support/backoff.h",
         "src/core/lib/support/block_annotate.h",
         "src/core/lib/support/env.h",
+        "src/core/lib/support/fork.h",
         "src/core/lib/support/memory.h",
         "src/core/lib/support/mpscq.h",
         "src/core/lib/support/murmur_hash.h",
@@ -524,6 +526,7 @@ grpc_cc_library(
         "src/core/lib/support/stack_lockfree.h",
         "src/core/lib/support/string.h",
         "src/core/lib/support/string_windows.h",
+        "src/core/lib/support/thd_internal.h",
         "src/core/lib/support/time_precise.h",
         "src/core/lib/support/tmpfile.h",
     ],
@@ -542,6 +545,7 @@ grpc_cc_library(
         "include/grpc/impl/codegen/atm_gcc_atomic.h",
         "include/grpc/impl/codegen/atm_gcc_sync.h",
         "include/grpc/impl/codegen/atm_windows.h",
+        "include/grpc/impl/codegen/fork.h",
         "include/grpc/impl/codegen/gpr_slice.h",
         "include/grpc/impl/codegen/gpr_types.h",
         "include/grpc/impl/codegen/port_platform.h",
@@ -597,6 +601,8 @@ grpc_cc_library(
         "src/core/lib/iomgr/ev_windows.c",
         "src/core/lib/iomgr/exec_ctx.c",
         "src/core/lib/iomgr/executor.c",
+        "src/core/lib/iomgr/fork_posix.c",
+        "src/core/lib/iomgr/fork_windows.c",
         "src/core/lib/iomgr/gethostname_fallback.c",
         "src/core/lib/iomgr/gethostname_host_name_max.c",
         "src/core/lib/iomgr/gethostname_sysconf.c",

CMakeLists.txt

@@ -795,6 +795,7 @@ add_library(gpr
   src/core/lib/support/env_linux.c
   src/core/lib/support/env_posix.c
   src/core/lib/support/env_windows.c
+  src/core/lib/support/fork.c
   src/core/lib/support/histogram.c
   src/core/lib/support/host_port.c
   src/core/lib/support/log.c
@@ -889,6 +890,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -988,6 +990,8 @@ add_library(grpc
   src/core/lib/iomgr/ev_windows.c
   src/core/lib/iomgr/exec_ctx.c
   src/core/lib/iomgr/executor.c
+  src/core/lib/iomgr/fork_posix.c
+  src/core/lib/iomgr/fork_windows.c
   src/core/lib/iomgr/gethostname_fallback.c
   src/core/lib/iomgr/gethostname_host_name_max.c
   src/core/lib/iomgr/gethostname_sysconf.c
@@ -1265,6 +1269,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -1277,6 +1282,7 @@ foreach(_hdr
   include/grpc/byte_buffer.h
   include/grpc/byte_buffer_reader.h
   include/grpc/compression.h
+  include/grpc/fork.h
   include/grpc/grpc.h
   include/grpc/grpc_posix.h
   include/grpc/grpc_security_constants.h
@@ -1339,6 +1345,8 @@ add_library(grpc_cronet
   src/core/lib/iomgr/ev_windows.c
   src/core/lib/iomgr/exec_ctx.c
   src/core/lib/iomgr/executor.c
+  src/core/lib/iomgr/fork_posix.c
+  src/core/lib/iomgr/fork_windows.c
   src/core/lib/iomgr/gethostname_fallback.c
   src/core/lib/iomgr/gethostname_host_name_max.c
   src/core/lib/iomgr/gethostname_sysconf.c
@@ -1574,6 +1582,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -1658,6 +1667,8 @@ add_library(grpc_test_util
   src/core/lib/iomgr/ev_windows.c
   src/core/lib/iomgr/exec_ctx.c
   src/core/lib/iomgr/executor.c
+  src/core/lib/iomgr/fork_posix.c
+  src/core/lib/iomgr/fork_windows.c
   src/core/lib/iomgr/gethostname_fallback.c
   src/core/lib/iomgr/gethostname_host_name_max.c
   src/core/lib/iomgr/gethostname_sysconf.c
@@ -1853,6 +1864,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -1921,6 +1933,8 @@ add_library(grpc_test_util_unsecure
   src/core/lib/iomgr/ev_windows.c
   src/core/lib/iomgr/exec_ctx.c
   src/core/lib/iomgr/executor.c
+  src/core/lib/iomgr/fork_posix.c
+  src/core/lib/iomgr/fork_windows.c
   src/core/lib/iomgr/gethostname_fallback.c
   src/core/lib/iomgr/gethostname_host_name_max.c
   src/core/lib/iomgr/gethostname_sysconf.c
@@ -2116,6 +2130,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -2170,6 +2185,8 @@ add_library(grpc_unsecure
   src/core/lib/iomgr/ev_windows.c
   src/core/lib/iomgr/exec_ctx.c
   src/core/lib/iomgr/executor.c
+  src/core/lib/iomgr/fork_posix.c
+  src/core/lib/iomgr/fork_windows.c
   src/core/lib/iomgr/gethostname_fallback.c
   src/core/lib/iomgr/gethostname_host_name_max.c
   src/core/lib/iomgr/gethostname_sysconf.c
@@ -2414,6 +2431,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -2425,6 +2443,7 @@ foreach(_hdr
   include/grpc/byte_buffer.h
   include/grpc/byte_buffer_reader.h
   include/grpc/compression.h
+  include/grpc/fork.h
   include/grpc/grpc.h
   include/grpc/grpc_posix.h
   include/grpc/grpc_security_constants.h
@@ -2692,6 +2711,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -2703,6 +2723,7 @@ foreach(_hdr
   include/grpc/byte_buffer.h
   include/grpc/byte_buffer_reader.h
   include/grpc/compression.h
+  include/grpc/fork.h
   include/grpc/grpc.h
   include/grpc/grpc_posix.h
   include/grpc/grpc_security_constants.h
@@ -2927,6 +2948,8 @@ add_library(grpc++_cronet
   src/core/lib/iomgr/ev_windows.c
   src/core/lib/iomgr/exec_ctx.c
   src/core/lib/iomgr/executor.c
+  src/core/lib/iomgr/fork_posix.c
+  src/core/lib/iomgr/fork_windows.c
   src/core/lib/iomgr/gethostname_fallback.c
   src/core/lib/iomgr/gethostname_host_name_max.c
   src/core/lib/iomgr/gethostname_sysconf.c
@@ -3188,6 +3211,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -3199,6 +3223,7 @@ foreach(_hdr
   include/grpc/byte_buffer.h
   include/grpc/byte_buffer_reader.h
   include/grpc/compression.h
+  include/grpc/fork.h
   include/grpc/grpc.h
   include/grpc/grpc_posix.h
   include/grpc/grpc_security_constants.h
@@ -3620,6 +3645,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -3760,6 +3786,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -3931,6 +3958,7 @@ foreach(_hdr
   include/grpc/impl/codegen/atm_gcc_atomic.h
   include/grpc/impl/codegen/atm_gcc_sync.h
   include/grpc/impl/codegen/atm_windows.h
+  include/grpc/impl/codegen/fork.h
   include/grpc/impl/codegen/gpr_slice.h
   include/grpc/impl/codegen/gpr_types.h
   include/grpc/impl/codegen/port_platform.h
@@ -3942,6 +3970,7 @@ foreach(_hdr
   include/grpc/byte_buffer.h
   include/grpc/byte_buffer_reader.h
   include/grpc/compression.h
+  include/grpc/fork.h
   include/grpc/grpc.h
   include/grpc/grpc_posix.h
   include/grpc/grpc_security_constants.h

Makefile

@@ -2809,6 +2809,7 @@ LIBGPR_SRC = \
     src/core/lib/support/env_linux.c \
     src/core/lib/support/env_posix.c \
     src/core/lib/support/env_windows.c \
+    src/core/lib/support/fork.c \
     src/core/lib/support/histogram.c \
     src/core/lib/support/host_port.c \
     src/core/lib/support/log.c \
@@ -2873,6 +2874,7 @@ PUBLIC_HEADERS_C += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -2979,6 +2981,8 @@ LIBGRPC_SRC = \
     src/core/lib/iomgr/ev_windows.c \
     src/core/lib/iomgr/exec_ctx.c \
     src/core/lib/iomgr/executor.c \
+    src/core/lib/iomgr/fork_posix.c \
+    src/core/lib/iomgr/fork_windows.c \
     src/core/lib/iomgr/gethostname_fallback.c \
     src/core/lib/iomgr/gethostname_host_name_max.c \
     src/core/lib/iomgr/gethostname_sysconf.c \
@@ -3221,6 +3225,7 @@ PUBLIC_HEADERS_C += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -3233,6 +3238,7 @@ PUBLIC_HEADERS_C += \
     include/grpc/byte_buffer.h \
     include/grpc/byte_buffer_reader.h \
     include/grpc/compression.h \
+    include/grpc/fork.h \
     include/grpc/grpc.h \
     include/grpc/grpc_posix.h \
     include/grpc/grpc_security_constants.h \
@@ -3330,6 +3336,8 @@ LIBGRPC_CRONET_SRC = \
     src/core/lib/iomgr/ev_windows.c \
     src/core/lib/iomgr/exec_ctx.c \
     src/core/lib/iomgr/executor.c \
+    src/core/lib/iomgr/fork_posix.c \
+    src/core/lib/iomgr/fork_windows.c \
     src/core/lib/iomgr/gethostname_fallback.c \
     src/core/lib/iomgr/gethostname_host_name_max.c \
     src/core/lib/iomgr/gethostname_sysconf.c \
@@ -3530,6 +3538,7 @@ PUBLIC_HEADERS_C += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -3648,6 +3657,8 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/lib/iomgr/ev_windows.c \
     src/core/lib/iomgr/exec_ctx.c \
     src/core/lib/iomgr/executor.c \
+    src/core/lib/iomgr/fork_posix.c \
+    src/core/lib/iomgr/fork_windows.c \
     src/core/lib/iomgr/gethostname_fallback.c \
     src/core/lib/iomgr/gethostname_host_name_max.c \
     src/core/lib/iomgr/gethostname_sysconf.c \
@@ -3810,6 +3821,7 @@ PUBLIC_HEADERS_C += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -3902,6 +3914,8 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \
     src/core/lib/iomgr/ev_windows.c \
     src/core/lib/iomgr/exec_ctx.c \
     src/core/lib/iomgr/executor.c \
+    src/core/lib/iomgr/fork_posix.c \
+    src/core/lib/iomgr/fork_windows.c \
     src/core/lib/iomgr/gethostname_fallback.c \
     src/core/lib/iomgr/gethostname_host_name_max.c \
     src/core/lib/iomgr/gethostname_sysconf.c \
@@ -4064,6 +4078,7 @@ PUBLIC_HEADERS_C += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -4129,6 +4144,8 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/lib/iomgr/ev_windows.c \
     src/core/lib/iomgr/exec_ctx.c \
     src/core/lib/iomgr/executor.c \
+    src/core/lib/iomgr/fork_posix.c \
+    src/core/lib/iomgr/fork_windows.c \
     src/core/lib/iomgr/gethostname_fallback.c \
     src/core/lib/iomgr/gethostname_host_name_max.c \
     src/core/lib/iomgr/gethostname_sysconf.c \
@@ -4339,6 +4356,7 @@ PUBLIC_HEADERS_C += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -4350,6 +4368,7 @@ PUBLIC_HEADERS_C += \
     include/grpc/byte_buffer.h \
     include/grpc/byte_buffer_reader.h \
     include/grpc/compression.h \
+    include/grpc/fork.h \
     include/grpc/grpc.h \
     include/grpc/grpc_posix.h \
     include/grpc/grpc_security_constants.h \
@@ -4596,6 +4615,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -4607,6 +4627,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/byte_buffer.h \
     include/grpc/byte_buffer_reader.h \
     include/grpc/compression.h \
+    include/grpc/fork.h \
     include/grpc/grpc.h \
     include/grpc/grpc_posix.h \
     include/grpc/grpc_security_constants.h \
@@ -4869,6 +4890,8 @@ LIBGRPC++_CRONET_SRC = \
     src/core/lib/iomgr/ev_windows.c \
     src/core/lib/iomgr/exec_ctx.c \
     src/core/lib/iomgr/executor.c \
+    src/core/lib/iomgr/fork_posix.c \
+    src/core/lib/iomgr/fork_windows.c \
     src/core/lib/iomgr/gethostname_fallback.c \
     src/core/lib/iomgr/gethostname_host_name_max.c \
     src/core/lib/iomgr/gethostname_sysconf.c \
@@ -5093,6 +5116,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -5104,6 +5128,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/byte_buffer.h \
     include/grpc/byte_buffer_reader.h \
     include/grpc/compression.h \
+    include/grpc/fork.h \
     include/grpc/grpc.h \
     include/grpc/grpc_posix.h \
     include/grpc/grpc_security_constants.h \
@@ -5518,6 +5543,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -5635,6 +5661,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -5811,6 +5838,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/impl/codegen/atm_gcc_atomic.h \
     include/grpc/impl/codegen/atm_gcc_sync.h \
     include/grpc/impl/codegen/atm_windows.h \
+    include/grpc/impl/codegen/fork.h \
     include/grpc/impl/codegen/gpr_slice.h \
     include/grpc/impl/codegen/gpr_types.h \
     include/grpc/impl/codegen/port_platform.h \
@@ -5822,6 +5850,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/byte_buffer.h \
     include/grpc/byte_buffer_reader.h \
     include/grpc/compression.h \
+    include/grpc/fork.h \
     include/grpc/grpc.h \
     include/grpc/grpc_posix.h \
     include/grpc/grpc_security_constants.h \

binding.gyp

@@ -608,6 +608,7 @@
         'src/core/lib/support/env_linux.c',
         'src/core/lib/support/env_posix.c',
         'src/core/lib/support/env_windows.c',
+        'src/core/lib/support/fork.c',
         'src/core/lib/support/histogram.c',
         'src/core/lib/support/host_port.c',
         'src/core/lib/support/log.c',
@@ -690,6 +691,8 @@
         'src/core/lib/iomgr/ev_windows.c',
         'src/core/lib/iomgr/exec_ctx.c',
         'src/core/lib/iomgr/executor.c',
+        'src/core/lib/iomgr/fork_posix.c',
+        'src/core/lib/iomgr/fork_windows.c',
         'src/core/lib/iomgr/gethostname_fallback.c',
         'src/core/lib/iomgr/gethostname_host_name_max.c',
         'src/core/lib/iomgr/gethostname_sysconf.c',

build.yaml

@@ -75,6 +75,7 @@ filegroups:
   - src/core/lib/support/env_linux.c
   - src/core/lib/support/env_posix.c
   - src/core/lib/support/env_windows.c
+  - src/core/lib/support/fork.c
   - src/core/lib/support/histogram.c
   - src/core/lib/support/host_port.c
   - src/core/lib/support/log.c
@@ -146,6 +147,7 @@ filegroups:
   - src/core/lib/support/backoff.h
   - src/core/lib/support/block_annotate.h
   - src/core/lib/support/env.h
+  - src/core/lib/support/fork.h
   - src/core/lib/support/memory.h
   - src/core/lib/support/mpscq.h
   - src/core/lib/support/murmur_hash.h
@@ -153,6 +155,7 @@ filegroups:
   - src/core/lib/support/stack_lockfree.h
   - src/core/lib/support/string.h
   - src/core/lib/support/string_windows.h
+  - src/core/lib/support/thd_internal.h
   - src/core/lib/support/time_precise.h
   - src/core/lib/support/tmpfile.h
   uses:
@@ -163,6 +166,7 @@ filegroups:
   - include/grpc/impl/codegen/atm_gcc_atomic.h
   - include/grpc/impl/codegen/atm_gcc_sync.h
   - include/grpc/impl/codegen/atm_windows.h
+  - include/grpc/impl/codegen/fork.h
   - include/grpc/impl/codegen/gpr_slice.h
   - include/grpc/impl/codegen/gpr_types.h
   - include/grpc/impl/codegen/port_platform.h
@@ -218,6 +222,8 @@ filegroups:
   - src/core/lib/iomgr/ev_windows.c
   - src/core/lib/iomgr/exec_ctx.c
   - src/core/lib/iomgr/executor.c
+  - src/core/lib/iomgr/fork_posix.c
+  - src/core/lib/iomgr/fork_windows.c
   - src/core/lib/iomgr/gethostname_fallback.c
   - src/core/lib/iomgr/gethostname_host_name_max.c
   - src/core/lib/iomgr/gethostname_sysconf.c
@@ -328,6 +334,7 @@ filegroups:
   - include/grpc/byte_buffer.h
   - include/grpc/byte_buffer_reader.h
   - include/grpc/compression.h
+  - include/grpc/fork.h
   - include/grpc/grpc.h
   - include/grpc/grpc_posix.h
   - include/grpc/grpc_security_constants.h

config.m4

@@ -54,6 +54,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/support/env_linux.c \
     src/core/lib/support/env_posix.c \
     src/core/lib/support/env_windows.c \
+    src/core/lib/support/fork.c \
     src/core/lib/support/histogram.c \
     src/core/lib/support/host_port.c \
     src/core/lib/support/log.c \
@@ -119,6 +120,8 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/iomgr/ev_windows.c \
     src/core/lib/iomgr/exec_ctx.c \
     src/core/lib/iomgr/executor.c \
+    src/core/lib/iomgr/fork_posix.c \
+    src/core/lib/iomgr/fork_windows.c \
     src/core/lib/iomgr/gethostname_fallback.c \
     src/core/lib/iomgr/gethostname_host_name_max.c \
     src/core/lib/iomgr/gethostname_sysconf.c \

config.w32

@@ -31,6 +31,7 @@ if (PHP_GRPC != "no") {
     "src\\core\\lib\\support\\env_linux.c " +
     "src\\core\\lib\\support\\env_posix.c " +
     "src\\core\\lib\\support\\env_windows.c " +
+    "src\\core\\lib\\support\\fork.c " +
     "src\\core\\lib\\support\\histogram.c " +
     "src\\core\\lib\\support\\host_port.c " +
     "src\\core\\lib\\support\\log.c " +
@@ -96,6 +97,8 @@ if (PHP_GRPC != "no") {
     "src\\core\\lib\\iomgr\\ev_windows.c " +
     "src\\core\\lib\\iomgr\\exec_ctx.c " +
     "src\\core\\lib\\iomgr\\executor.c " +
+    "src\\core\\lib\\iomgr\\fork_posix.c " +
+    "src\\core\\lib\\iomgr\\fork_windows.c " +
     "src\\core\\lib\\iomgr\\gethostname_fallback.c " +
     "src\\core\\lib\\iomgr\\gethostname_host_name_max.c " +
     "src\\core\\lib\\iomgr\\gethostname_sysconf.c " +

gRPC-Core.podspec

@@ -134,6 +134,7 @@ Pod::Spec.new do |s|
                       'include/grpc/impl/codegen/atm_gcc_atomic.h',
                       'include/grpc/impl/codegen/atm_gcc_sync.h',
                       'include/grpc/impl/codegen/atm_windows.h',
+                      'include/grpc/impl/codegen/fork.h',
                       'include/grpc/impl/codegen/gpr_slice.h',
                       'include/grpc/impl/codegen/gpr_types.h',
                       'include/grpc/impl/codegen/port_platform.h',
@@ -155,6 +156,7 @@ Pod::Spec.new do |s|
                       'include/grpc/impl/codegen/atm_gcc_atomic.h',
                       'include/grpc/impl/codegen/atm_gcc_sync.h',
                       'include/grpc/impl/codegen/atm_windows.h',
+                      'include/grpc/impl/codegen/fork.h',
                       'include/grpc/impl/codegen/gpr_slice.h',
                       'include/grpc/impl/codegen/gpr_types.h',
                       'include/grpc/impl/codegen/port_platform.h',
@@ -167,6 +169,7 @@ Pod::Spec.new do |s|
                       'include/grpc/byte_buffer.h',
                       'include/grpc/byte_buffer_reader.h',
                       'include/grpc/compression.h',
+                      'include/grpc/fork.h',
                       'include/grpc/grpc.h',
                       'include/grpc/grpc_posix.h',
                       'include/grpc/grpc_security_constants.h',
@@ -193,6 +196,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/support/backoff.h',
                       'src/core/lib/support/block_annotate.h',
                       'src/core/lib/support/env.h',
+                      'src/core/lib/support/fork.h',
                       'src/core/lib/support/memory.h',
                       'src/core/lib/support/mpscq.h',
                       'src/core/lib/support/murmur_hash.h',
@@ -200,6 +204,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/support/stack_lockfree.h',
                       'src/core/lib/support/string.h',
                       'src/core/lib/support/string_windows.h',
+                      'src/core/lib/support/thd_internal.h',
                       'src/core/lib/support/time_precise.h',
                       'src/core/lib/support/tmpfile.h',
                       'src/core/lib/profiling/basic_timers.c',
@@ -217,6 +222,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/support/env_linux.c',
                       'src/core/lib/support/env_posix.c',
                       'src/core/lib/support/env_windows.c',
+                      'src/core/lib/support/fork.c',
                       'src/core/lib/support/histogram.c',
                       'src/core/lib/support/host_port.c',
                       'src/core/lib/support/log.c',
@@ -505,6 +511,8 @@ Pod::Spec.new do |s|
                       'src/core/lib/iomgr/ev_windows.c',
                       'src/core/lib/iomgr/exec_ctx.c',
                       'src/core/lib/iomgr/executor.c',
+                      'src/core/lib/iomgr/fork_posix.c',
+                      'src/core/lib/iomgr/fork_windows.c',
                       'src/core/lib/iomgr/gethostname_fallback.c',
                       'src/core/lib/iomgr/gethostname_host_name_max.c',
                       'src/core/lib/iomgr/gethostname_sysconf.c',
@@ -738,6 +746,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/support/backoff.h',
                               'src/core/lib/support/block_annotate.h',
                               'src/core/lib/support/env.h',
+                              'src/core/lib/support/fork.h',
                               'src/core/lib/support/memory.h',
                               'src/core/lib/support/mpscq.h',
                               'src/core/lib/support/murmur_hash.h',
@@ -745,6 +754,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/support/stack_lockfree.h',
                               'src/core/lib/support/string.h',
                               'src/core/lib/support/string_windows.h',
+                              'src/core/lib/support/thd_internal.h',
                               'src/core/lib/support/time_precise.h',
                               'src/core/lib/support/tmpfile.h',
                               'src/core/ext/transport/chttp2/transport/bin_decoder.h',

grpc.gemspec

@@ -75,6 +75,7 @@ Gem::Specification.new do |s|
   s.files += %w( include/grpc/impl/codegen/atm_gcc_atomic.h )
   s.files += %w( include/grpc/impl/codegen/atm_gcc_sync.h )
   s.files += %w( include/grpc/impl/codegen/atm_windows.h )
+  s.files += %w( include/grpc/impl/codegen/fork.h )
   s.files += %w( include/grpc/impl/codegen/gpr_slice.h )
   s.files += %w( include/grpc/impl/codegen/gpr_types.h )
   s.files += %w( include/grpc/impl/codegen/port_platform.h )
@@ -91,6 +92,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/support/backoff.h )
   s.files += %w( src/core/lib/support/block_annotate.h )
   s.files += %w( src/core/lib/support/env.h )
+  s.files += %w( src/core/lib/support/fork.h )
   s.files += %w( src/core/lib/support/memory.h )
   s.files += %w( src/core/lib/support/mpscq.h )
   s.files += %w( src/core/lib/support/murmur_hash.h )
@@ -98,6 +100,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/support/stack_lockfree.h )
   s.files += %w( src/core/lib/support/string.h )
   s.files += %w( src/core/lib/support/string_windows.h )
+  s.files += %w( src/core/lib/support/thd_internal.h )
   s.files += %w( src/core/lib/support/time_precise.h )
   s.files += %w( src/core/lib/support/tmpfile.h )
   s.files += %w( src/core/lib/profiling/basic_timers.c )
@@ -115,6 +118,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/support/env_linux.c )
   s.files += %w( src/core/lib/support/env_posix.c )
   s.files += %w( src/core/lib/support/env_windows.c )
+  s.files += %w( src/core/lib/support/fork.c )
   s.files += %w( src/core/lib/support/histogram.c )
   s.files += %w( src/core/lib/support/host_port.c )
   s.files += %w( src/core/lib/support/log.c )
@@ -159,6 +163,7 @@ Gem::Specification.new do |s|
   s.files += %w( include/grpc/impl/codegen/atm_gcc_atomic.h )
   s.files += %w( include/grpc/impl/codegen/atm_gcc_sync.h )
   s.files += %w( include/grpc/impl/codegen/atm_windows.h )
+  s.files += %w( include/grpc/impl/codegen/fork.h )
   s.files += %w( include/grpc/impl/codegen/gpr_slice.h )
   s.files += %w( include/grpc/impl/codegen/gpr_types.h )
   s.files += %w( include/grpc/impl/codegen/port_platform.h )
@@ -171,6 +176,7 @@ Gem::Specification.new do |s|
   s.files += %w( include/grpc/byte_buffer.h )
   s.files += %w( include/grpc/byte_buffer_reader.h )
   s.files += %w( include/grpc/compression.h )
+  s.files += %w( include/grpc/fork.h )
   s.files += %w( include/grpc/grpc.h )
   s.files += %w( include/grpc/grpc_posix.h )
   s.files += %w( include/grpc/grpc_security_constants.h )
@@ -441,6 +447,8 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/iomgr/ev_windows.c )
   s.files += %w( src/core/lib/iomgr/exec_ctx.c )
   s.files += %w( src/core/lib/iomgr/executor.c )
+  s.files += %w( src/core/lib/iomgr/fork_posix.c )
+  s.files += %w( src/core/lib/iomgr/fork_windows.c )
   s.files += %w( src/core/lib/iomgr/gethostname_fallback.c )
   s.files += %w( src/core/lib/iomgr/gethostname_host_name_max.c )
   s.files += %w( src/core/lib/iomgr/gethostname_sysconf.c )

grpc.gyp

@@ -172,6 +172,7 @@
         'src/core/lib/support/env_linux.c',
         'src/core/lib/support/env_posix.c',
         'src/core/lib/support/env_windows.c',
+        'src/core/lib/support/fork.c',
         'src/core/lib/support/histogram.c',
         'src/core/lib/support/host_port.c',
         'src/core/lib/support/log.c',
@@ -256,6 +257,8 @@
         'src/core/lib/iomgr/ev_windows.c',
         'src/core/lib/iomgr/exec_ctx.c',
         'src/core/lib/iomgr/executor.c',
+        'src/core/lib/iomgr/fork_posix.c',
+        'src/core/lib/iomgr/fork_windows.c',
         'src/core/lib/iomgr/gethostname_fallback.c',
         'src/core/lib/iomgr/gethostname_host_name_max.c',
         'src/core/lib/iomgr/gethostname_sysconf.c',
@@ -557,6 +560,8 @@
         'src/core/lib/iomgr/ev_windows.c',
         'src/core/lib/iomgr/exec_ctx.c',
         'src/core/lib/iomgr/executor.c',
+        'src/core/lib/iomgr/fork_posix.c',
+        'src/core/lib/iomgr/fork_windows.c',
         'src/core/lib/iomgr/gethostname_fallback.c',
         'src/core/lib/iomgr/gethostname_host_name_max.c',
         'src/core/lib/iomgr/gethostname_sysconf.c',
@@ -763,6 +768,8 @@
         'src/core/lib/iomgr/ev_windows.c',
         'src/core/lib/iomgr/exec_ctx.c',
         'src/core/lib/iomgr/executor.c',
+        'src/core/lib/iomgr/fork_posix.c',
+        'src/core/lib/iomgr/fork_windows.c',
         'src/core/lib/iomgr/gethostname_fallback.c',
         'src/core/lib/iomgr/gethostname_host_name_max.c',
         'src/core/lib/iomgr/gethostname_sysconf.c',
@@ -954,6 +961,8 @@
         'src/core/lib/iomgr/ev_windows.c',
         'src/core/lib/iomgr/exec_ctx.c',
         'src/core/lib/iomgr/executor.c',
+        'src/core/lib/iomgr/fork_posix.c',
+        'src/core/lib/iomgr/fork_windows.c',
         'src/core/lib/iomgr/gethostname_fallback.c',
         'src/core/lib/iomgr/gethostname_host_name_max.c',
         'src/core/lib/iomgr/gethostname_sysconf.c',

include/grpc/fork.h

@@ -0,0 +1,24 @@
+/*
+ *
+ * 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_FORK_H
+#define GRPC_FORK_H
+
+#include <grpc/impl/codegen/fork.h>
+
+#endif /* GRPC_FORK_H */

include/grpc/impl/codegen/fork.h

@@ -0,0 +1,49 @@
+/*
+ *
+ * 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_IMPL_CODEGEN_FORK_H
+#define GRPC_IMPL_CODEGEN_FORK_H
+
+/**
+ * gRPC applications should call this before calling fork().  There should be no
+ * active gRPC function calls between calling grpc_prefork() and
+ * grpc_postfork_parent()/grpc_postfork_child().
+ *
+ * Returns 1 on success, 0 otherwise.
+ *
+ * Typical use:
+ * assert(grpc_prefork() == 1);
+ * int pid = fork();
+ * if (pid) {
+ *  grpc_postfork_parent();
+ *  // Parent process..
+ * } else {
+ *  grpc_postfork_child();
+ *  // Child process...
+ * }
+ */
+
+int grpc_prefork();
+
+void grpc_postfork_parent();
+
+void grpc_postfork_child();
+
+void grpc_fork_handlers_auto_register();
+
+#endif /* GRPC_IMPL_CODEGEN_FORK_H */

include/grpc/module.modulemap

@@ -21,6 +21,7 @@ framework module grpc {
   header "support/tls.h"
   header "support/useful.h"
   header "impl/codegen/atm.h"
+  header "impl/codegen/fork.h"
   header "impl/codegen/gpr_slice.h"
   header "impl/codegen/gpr_types.h"
   header "impl/codegen/port_platform.h"
@@ -36,6 +37,7 @@ framework module grpc {
   header "impl/codegen/slice.h"
   header "impl/codegen/status.h"
   header "impl/codegen/atm.h"
+  header "impl/codegen/fork.h"
   header "impl/codegen/gpr_slice.h"
   header "impl/codegen/gpr_types.h"
   header "impl/codegen/port_platform.h"
@@ -45,6 +47,7 @@ framework module grpc {
   header "byte_buffer.h"
   header "byte_buffer_reader.h"
   header "compression.h"
+  header "fork.h"
   header "grpc.h"
   header "grpc_posix.h"
   header "grpc_security_constants.h"

package.xml

@@ -87,6 +87,7 @@
     <file baseinstalldir="/" name="include/grpc/impl/codegen/atm_gcc_atomic.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/atm_gcc_sync.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/atm_windows.h" role="src" />
+    <file baseinstalldir="/" name="include/grpc/impl/codegen/fork.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/gpr_slice.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/gpr_types.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/port_platform.h" role="src" />
@@ -103,6 +104,7 @@
     <file baseinstalldir="/" name="src/core/lib/support/backoff.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/block_annotate.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/env.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/support/fork.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/memory.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/mpscq.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/murmur_hash.h" role="src" />
@@ -110,6 +112,7 @@
     <file baseinstalldir="/" name="src/core/lib/support/stack_lockfree.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/string.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/string_windows.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/support/thd_internal.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/time_precise.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/tmpfile.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/profiling/basic_timers.c" role="src" />
@@ -127,6 +130,7 @@
     <file baseinstalldir="/" name="src/core/lib/support/env_linux.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/env_posix.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/env_windows.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/support/fork.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/histogram.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/host_port.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/log.c" role="src" />
@@ -171,6 +175,7 @@
     <file baseinstalldir="/" name="include/grpc/impl/codegen/atm_gcc_atomic.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/atm_gcc_sync.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/atm_windows.h" role="src" />
+    <file baseinstalldir="/" name="include/grpc/impl/codegen/fork.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/gpr_slice.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/gpr_types.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/impl/codegen/port_platform.h" role="src" />
@@ -183,6 +188,7 @@
     <file baseinstalldir="/" name="include/grpc/byte_buffer.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/byte_buffer_reader.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/compression.h" role="src" />
+    <file baseinstalldir="/" name="include/grpc/fork.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/grpc.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/grpc_posix.h" role="src" />
     <file baseinstalldir="/" name="include/grpc/grpc_security_constants.h" role="src" />
@@ -453,6 +459,8 @@
     <file baseinstalldir="/" name="src/core/lib/iomgr/ev_windows.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/exec_ctx.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/executor.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/iomgr/fork_posix.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/iomgr/fork_windows.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/gethostname_fallback.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/gethostname_host_name_max.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/gethostname_sysconf.c" role="src" />

setup.py

@@ -169,7 +169,7 @@ if "win32" in sys.platform:
     # on msvc, but only for 32 bits
     DEFINE_MACROS += (('NTDDI_VERSION', 0x06000000),)
 else:
-  DEFINE_MACROS += (('HAVE_CONFIG_H', 1),)
+  DEFINE_MACROS += (('HAVE_CONFIG_H', 1), ('GRPC_ENABLE_FORK_SUPPORT', 1),)
 
 LDFLAGS = tuple(EXTRA_LINK_ARGS)
 CFLAGS = tuple(EXTRA_COMPILE_ARGS)

src/core/lib/iomgr/fork_posix.c

@@ -0,0 +1,83 @@
+/*
+ *
+ * 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"
+
+/*
+ * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK
+ *       AROUND VERY SPECIFIC USE CASES.
+ */
+
+int 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 0;
+  }
+  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!");
+    return 0;
+  }
+  return 1;
+}
+
+void grpc_postfork_parent() {
+  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() {
+  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

src/core/lib/iomgr/fork_windows.c

@@ -0,0 +1,42 @@
+/*
+ *
+ * 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.
+ */
+
+int grpc_prefork() {
+  gpr_log(GPR_ERROR, "Forking not supported on Windows");
+  return 0;
+}
+
+void grpc_postfork_parent() {}
+
+void grpc_postfork_child() {}
+
+void grpc_fork_handlers_auto_register() {}
+
+#endif  // GRPC_POSIX_FORK

src/core/lib/support/fork.c

@@ -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;
+}

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 */

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 */

src/core/lib/support/thd_posix.c

@@ -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 NULL;
 }
 
@@ -54,6 +66,7 @@ int gpr_thd_new(gpr_thd_id *t, void (*thd_body)(void *arg), void *arg,
   GPR_ASSERT(a != NULL);
   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, NULL); }
 
+/*****************************************
+ * 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 */

src/core/lib/support/thd_windows.c

@@ -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;

src/core/lib/surface/init.c

@@ -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"
@@ -62,9 +65,11 @@ 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();
   g_initializations = 0;
+  grpc_fork_handlers_auto_register();
 }
 
 static bool append_filter(grpc_exec_ctx *exec_ctx,
@@ -121,6 +126,7 @@ 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();

src/python/grpcio/grpc_core_dependencies.py

@@ -30,6 +30,7 @@ CORE_SOURCE_FILES = [
   'src/core/lib/support/env_linux.c',
   'src/core/lib/support/env_posix.c',
   'src/core/lib/support/env_windows.c',
+  'src/core/lib/support/fork.c',
   'src/core/lib/support/histogram.c',
   'src/core/lib/support/host_port.c',
   'src/core/lib/support/log.c',
@@ -95,6 +96,8 @@ CORE_SOURCE_FILES = [
   'src/core/lib/iomgr/ev_windows.c',
   'src/core/lib/iomgr/exec_ctx.c',
   'src/core/lib/iomgr/executor.c',
+  'src/core/lib/iomgr/fork_posix.c',
+  'src/core/lib/iomgr/fork_windows.c',
   'src/core/lib/iomgr/gethostname_fallback.c',
   'src/core/lib/iomgr/gethostname_host_name_max.c',
   'src/core/lib/iomgr/gethostname_sysconf.c',

test/core/surface/public_headers_must_be_c89.c

@@ -20,6 +20,7 @@
 #include <grpc/byte_buffer_reader.h>
 #include <grpc/census.h>
 #include <grpc/compression.h>
+#include <grpc/fork.h>
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
 #include <grpc/grpc_security_constants.h>
@@ -29,6 +30,7 @@
 #include <grpc/impl/codegen/compression_types.h>
 #include <grpc/impl/codegen/connectivity_state.h>
 #include <grpc/impl/codegen/exec_ctx_fwd.h>
+#include <grpc/impl/codegen/fork.h>
 #include <grpc/impl/codegen/gpr_slice.h>
 #include <grpc/impl/codegen/gpr_types.h>
 #include <grpc/impl/codegen/grpc_types.h>

tools/doxygen/Doxyfile.c++

@@ -875,6 +875,7 @@ include/grpc++/support/time.h \
 include/grpc/byte_buffer.h \
 include/grpc/byte_buffer_reader.h \
 include/grpc/compression.h \
+include/grpc/fork.h \
 include/grpc/grpc.h \
 include/grpc/grpc_posix.h \
 include/grpc/grpc_security_constants.h \
@@ -887,6 +888,7 @@ include/grpc/impl/codegen/byte_buffer_reader.h \
 include/grpc/impl/codegen/compression_types.h \
 include/grpc/impl/codegen/connectivity_state.h \
 include/grpc/impl/codegen/exec_ctx_fwd.h \
+include/grpc/impl/codegen/fork.h \
 include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_types.h \
 include/grpc/impl/codegen/grpc_types.h \

tools/doxygen/Doxyfile.c++.internal

@@ -876,6 +876,7 @@ include/grpc++/support/time.h \
 include/grpc/byte_buffer.h \
 include/grpc/byte_buffer_reader.h \
 include/grpc/compression.h \
+include/grpc/fork.h \
 include/grpc/grpc.h \
 include/grpc/grpc_posix.h \
 include/grpc/grpc_security_constants.h \
@@ -888,6 +889,7 @@ include/grpc/impl/codegen/byte_buffer_reader.h \
 include/grpc/impl/codegen/compression_types.h \
 include/grpc/impl/codegen/connectivity_state.h \
 include/grpc/impl/codegen/exec_ctx_fwd.h \
+include/grpc/impl/codegen/fork.h \
 include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_types.h \
 include/grpc/impl/codegen/grpc_types.h \
@@ -1031,6 +1033,7 @@ src/core/lib/support/atomic_with_std.h \
 src/core/lib/support/backoff.h \
 src/core/lib/support/block_annotate.h \
 src/core/lib/support/env.h \
+src/core/lib/support/fork.h \
 src/core/lib/support/memory.h \
 src/core/lib/support/mpscq.h \
 src/core/lib/support/murmur_hash.h \
@@ -1038,6 +1041,7 @@ src/core/lib/support/spinlock.h \
 src/core/lib/support/stack_lockfree.h \
 src/core/lib/support/string.h \
 src/core/lib/support/string_windows.h \
+src/core/lib/support/thd_internal.h \
 src/core/lib/support/time_precise.h \
 src/core/lib/support/tmpfile.h \
 src/core/lib/surface/alarm_internal.h \

tools/doxygen/Doxyfile.core

@@ -799,6 +799,7 @@ include/grpc/byte_buffer.h \
 include/grpc/byte_buffer_reader.h \
 include/grpc/census.h \
 include/grpc/compression.h \
+include/grpc/fork.h \
 include/grpc/grpc.h \
 include/grpc/grpc_posix.h \
 include/grpc/grpc_security.h \
@@ -816,6 +817,8 @@ include/grpc/impl/codegen/byte_buffer_reader.h \
 include/grpc/impl/codegen/compression_types.h \
 include/grpc/impl/codegen/connectivity_state.h \
 include/grpc/impl/codegen/exec_ctx_fwd.h \
+include/grpc/impl/codegen/fork.h \
+include/grpc/impl/codegen/fork.h \
 include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_types.h \

tools/doxygen/Doxyfile.core.internal

@@ -799,6 +799,7 @@ include/grpc/byte_buffer.h \
 include/grpc/byte_buffer_reader.h \
 include/grpc/census.h \
 include/grpc/compression.h \
+include/grpc/fork.h \
 include/grpc/grpc.h \
 include/grpc/grpc_posix.h \
 include/grpc/grpc_security.h \
@@ -816,6 +817,8 @@ include/grpc/impl/codegen/byte_buffer_reader.h \
 include/grpc/impl/codegen/compression_types.h \
 include/grpc/impl/codegen/connectivity_state.h \
 include/grpc/impl/codegen/exec_ctx_fwd.h \
+include/grpc/impl/codegen/fork.h \
+include/grpc/impl/codegen/fork.h \
 include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_types.h \
@@ -1126,6 +1129,8 @@ src/core/lib/iomgr/exec_ctx.c \
 src/core/lib/iomgr/exec_ctx.h \
 src/core/lib/iomgr/executor.c \
 src/core/lib/iomgr/executor.h \
+src/core/lib/iomgr/fork_posix.c \
+src/core/lib/iomgr/fork_windows.c \
 src/core/lib/iomgr/gethostname.h \
 src/core/lib/iomgr/gethostname_fallback.c \
 src/core/lib/iomgr/gethostname_host_name_max.c \
@@ -1313,6 +1318,8 @@ src/core/lib/support/env.h \
 src/core/lib/support/env_linux.c \
 src/core/lib/support/env_posix.c \
 src/core/lib/support/env_windows.c \
+src/core/lib/support/fork.c \
+src/core/lib/support/fork.h \
 src/core/lib/support/histogram.c \
 src/core/lib/support/host_port.c \
 src/core/lib/support/log.c \
@@ -1340,6 +1347,7 @@ src/core/lib/support/sync.c \
 src/core/lib/support/sync_posix.c \
 src/core/lib/support/sync_windows.c \
 src/core/lib/support/thd.c \
+src/core/lib/support/thd_internal.h \
 src/core/lib/support/thd_posix.c \
 src/core/lib/support/thd_windows.c \
 src/core/lib/support/time.c \

tools/run_tests/generated/sources_and_headers.json

@@ -7782,6 +7782,7 @@
       "src/core/lib/support/env_linux.c", 
       "src/core/lib/support/env_posix.c", 
       "src/core/lib/support/env_windows.c", 
+      "src/core/lib/support/fork.c", 
       "src/core/lib/support/histogram.c", 
       "src/core/lib/support/host_port.c", 
       "src/core/lib/support/log.c", 
@@ -7857,6 +7858,7 @@
       "src/core/lib/support/backoff.h", 
       "src/core/lib/support/block_annotate.h", 
       "src/core/lib/support/env.h", 
+      "src/core/lib/support/fork.h", 
       "src/core/lib/support/memory.h", 
       "src/core/lib/support/mpscq.h", 
       "src/core/lib/support/murmur_hash.h", 
@@ -7864,6 +7866,7 @@
       "src/core/lib/support/stack_lockfree.h", 
       "src/core/lib/support/string.h", 
       "src/core/lib/support/string_windows.h", 
+      "src/core/lib/support/thd_internal.h", 
       "src/core/lib/support/time_precise.h", 
       "src/core/lib/support/tmpfile.h"
     ], 
@@ -7906,6 +7909,7 @@
       "src/core/lib/support/backoff.h", 
       "src/core/lib/support/block_annotate.h", 
       "src/core/lib/support/env.h", 
+      "src/core/lib/support/fork.h", 
       "src/core/lib/support/memory.h", 
       "src/core/lib/support/mpscq.h", 
       "src/core/lib/support/murmur_hash.h", 
@@ -7913,6 +7917,7 @@
       "src/core/lib/support/stack_lockfree.h", 
       "src/core/lib/support/string.h", 
       "src/core/lib/support/string_windows.h", 
+      "src/core/lib/support/thd_internal.h", 
       "src/core/lib/support/time_precise.h", 
       "src/core/lib/support/tmpfile.h"
     ], 
@@ -7926,6 +7931,7 @@
       "include/grpc/impl/codegen/atm_gcc_atomic.h", 
       "include/grpc/impl/codegen/atm_gcc_sync.h", 
       "include/grpc/impl/codegen/atm_windows.h", 
+      "include/grpc/impl/codegen/fork.h", 
       "include/grpc/impl/codegen/gpr_slice.h", 
       "include/grpc/impl/codegen/gpr_types.h", 
       "include/grpc/impl/codegen/port_platform.h", 
@@ -7943,6 +7949,7 @@
       "include/grpc/impl/codegen/atm_gcc_atomic.h", 
       "include/grpc/impl/codegen/atm_gcc_sync.h", 
       "include/grpc/impl/codegen/atm_windows.h", 
+      "include/grpc/impl/codegen/fork.h", 
       "include/grpc/impl/codegen/gpr_slice.h", 
       "include/grpc/impl/codegen/gpr_types.h", 
       "include/grpc/impl/codegen/port_platform.h", 
@@ -8030,6 +8037,8 @@
       "src/core/lib/iomgr/ev_windows.c", 
       "src/core/lib/iomgr/exec_ctx.c", 
       "src/core/lib/iomgr/executor.c", 
+      "src/core/lib/iomgr/fork_posix.c", 
+      "src/core/lib/iomgr/fork_windows.c", 
       "src/core/lib/iomgr/gethostname_fallback.c", 
       "src/core/lib/iomgr/gethostname_host_name_max.c", 
       "src/core/lib/iomgr/gethostname_sysconf.c", 
@@ -8142,6 +8151,7 @@
       "include/grpc/byte_buffer.h", 
       "include/grpc/byte_buffer_reader.h", 
       "include/grpc/compression.h", 
+      "include/grpc/fork.h", 
       "include/grpc/grpc.h", 
       "include/grpc/grpc_posix.h", 
       "include/grpc/grpc_security_constants.h", 
@@ -8275,6 +8285,7 @@
       "include/grpc/byte_buffer.h", 
       "include/grpc/byte_buffer_reader.h", 
       "include/grpc/compression.h", 
+      "include/grpc/fork.h", 
       "include/grpc/grpc.h", 
       "include/grpc/grpc_posix.h", 
       "include/grpc/grpc_security_constants.h",