Merge branch 'master' into cmake-export-fix

54 files changed, 4853 insertions, 0 deletions

diff --git a/src/core/lib/gpr/README.md b/src/core/lib/gpr/README.md
new file mode 100644
index 0000000000..21fb0c796d
--- /dev/null
+++ b/src/core/lib/gpr/README.md
@@ -0,0 +1,8 @@
+# GPR - Google Portable Runtime for C
+
+The files in this directory contain basic utility code and platform
+abstractions for C code.  None of this code is gRPC-specific; anything
+here may also be useful for other open source projects written in C.
+
+Note that this is one of the few places in src/core where we allow
+the use of portability macros.
diff --git a/src/core/lib/gpr/alloc.cc b/src/core/lib/gpr/alloc.cc
new file mode 100644
index 0000000000..518bdb99f7
--- /dev/null
+++ b/src/core/lib/gpr/alloc.cc
@@ -0,0 +1,102 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/alloc.h>
+
+#include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
+#include <stdlib.h>
+#include <string.h>
+#include "src/core/lib/profiling/timers.h"
+
+static void* zalloc_with_calloc(size_t sz) { return calloc(sz, 1); }
+
+static void* zalloc_with_gpr_malloc(size_t sz) {
+  void* p = gpr_malloc(sz);
+  memset(p, 0, sz);
+  return p;
+}
+
+static gpr_allocation_functions g_alloc_functions = {malloc, zalloc_with_calloc,
+                                                     realloc, free};
+
+gpr_allocation_functions gpr_get_allocation_functions() {
+  return g_alloc_functions;
+}
+
+void gpr_set_allocation_functions(gpr_allocation_functions functions) {
+  GPR_ASSERT(functions.malloc_fn != nullptr);
+  GPR_ASSERT(functions.realloc_fn != nullptr);
+  GPR_ASSERT(functions.free_fn != nullptr);
+  if (functions.zalloc_fn == nullptr) {
+    functions.zalloc_fn = zalloc_with_gpr_malloc;
+  }
+  g_alloc_functions = functions;
+}
+
+void* gpr_malloc(size_t size) {
+  void* p;
+  if (size == 0) return nullptr;
+  GPR_TIMER_BEGIN("gpr_malloc", 0);
+  p = g_alloc_functions.malloc_fn(size);
+  if (!p) {
+    abort();
+  }
+  GPR_TIMER_END("gpr_malloc", 0);
+  return p;
+}
+
+void* gpr_zalloc(size_t size) {
+  void* p;
+  if (size == 0) return nullptr;
+  GPR_TIMER_BEGIN("gpr_zalloc", 0);
+  p = g_alloc_functions.zalloc_fn(size);
+  if (!p) {
+    abort();
+  }
+  GPR_TIMER_END("gpr_zalloc", 0);
+  return p;
+}
+
+void gpr_free(void* p) {
+  GPR_TIMER_BEGIN("gpr_free", 0);
+  g_alloc_functions.free_fn(p);
+  GPR_TIMER_END("gpr_free", 0);
+}
+
+void* gpr_realloc(void* p, size_t size) {
+  if ((size == 0) && (p == nullptr)) return nullptr;
+  GPR_TIMER_BEGIN("gpr_realloc", 0);
+  p = g_alloc_functions.realloc_fn(p, size);
+  if (!p) {
+    abort();
+  }
+  GPR_TIMER_END("gpr_realloc", 0);
+  return p;
+}
+
+void* gpr_malloc_aligned(size_t size, size_t alignment_log) {
+  size_t alignment = ((size_t)1) << alignment_log;
+  size_t extra = alignment - 1 + sizeof(void*);
+  void* p = gpr_malloc(size + extra);
+  void** ret = (void**)(((uintptr_t)p + extra) & ~(alignment - 1));
+  ret[-1] = p;
+  return (void*)ret;
+}
+
+void gpr_free_aligned(void* ptr) { gpr_free(((void**)ptr)[-1]); }
diff --git a/src/core/lib/gpr/arena.cc b/src/core/lib/gpr/arena.cc
new file mode 100644
index 0000000000..177c176732
--- /dev/null
+++ b/src/core/lib/gpr/arena.cc
@@ -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/gpr/arena.h"
+#include <grpc/support/alloc.h>
+#include <grpc/support/atm.h>
+#include <grpc/support/log.h>
+#include <grpc/support/useful.h>
+
+#define ROUND_UP_TO_ALIGNMENT_SIZE(x) \
+  (((x) + GPR_MAX_ALIGNMENT - 1u) & ~(GPR_MAX_ALIGNMENT - 1u))
+
+typedef struct zone {
+  size_t size_begin;
+  size_t size_end;
+  gpr_atm next_atm;
+} zone;
+
+struct gpr_arena {
+  gpr_atm size_so_far;
+  zone initial_zone;
+};
+
+gpr_arena* gpr_arena_create(size_t initial_size) {
+  initial_size = ROUND_UP_TO_ALIGNMENT_SIZE(initial_size);
+  gpr_arena* a = (gpr_arena*)gpr_zalloc(sizeof(gpr_arena) + initial_size);
+  a->initial_zone.size_end = initial_size;
+  return a;
+}
+
+size_t gpr_arena_destroy(gpr_arena* arena) {
+  gpr_atm size = gpr_atm_no_barrier_load(&arena->size_so_far);
+  zone* z = (zone*)gpr_atm_no_barrier_load(&arena->initial_zone.next_atm);
+  gpr_free(arena);
+  while (z) {
+    zone* next_z = (zone*)gpr_atm_no_barrier_load(&z->next_atm);
+    gpr_free(z);
+    z = next_z;
+  }
+  return (size_t)size;
+}
+
+void* gpr_arena_alloc(gpr_arena* arena, size_t size) {
+  size = ROUND_UP_TO_ALIGNMENT_SIZE(size);
+  size_t start =
+      (size_t)gpr_atm_no_barrier_fetch_add(&arena->size_so_far, size);
+  zone* z = &arena->initial_zone;
+  while (start > z->size_end) {
+    zone* next_z = (zone*)gpr_atm_acq_load(&z->next_atm);
+    if (next_z == nullptr) {
+      size_t next_z_size = (size_t)gpr_atm_no_barrier_load(&arena->size_so_far);
+      next_z = (zone*)gpr_zalloc(sizeof(zone) + next_z_size);
+      next_z->size_begin = z->size_end;
+      next_z->size_end = z->size_end + next_z_size;
+      if (!gpr_atm_rel_cas(&z->next_atm, (gpr_atm)NULL, (gpr_atm)next_z)) {
+        gpr_free(next_z);
+        next_z = (zone*)gpr_atm_acq_load(&z->next_atm);
+      }
+    }
+    z = next_z;
+  }
+  if (start + size > z->size_end) {
+    return gpr_arena_alloc(arena, size);
+  }
+  GPR_ASSERT(start >= z->size_begin);
+  GPR_ASSERT(start + size <= z->size_end);
+  return ((char*)(z + 1)) + start - z->size_begin;
+}
diff --git a/src/core/lib/gpr/arena.h b/src/core/lib/gpr/arena.h
new file mode 100644
index 0000000000..339771c0e3
--- /dev/null
+++ b/src/core/lib/gpr/arena.h
@@ -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.
+ *
+ */
+
+// \file Arena based allocator
+// Allows very fast allocation of memory, but that memory cannot be freed until
+// the arena as a whole is freed
+// Tracks the total memory allocated against it, so that future arenas can
+// pre-allocate the right amount of memory
+
+#ifndef GRPC_CORE_LIB_GPR_ARENA_H
+#define GRPC_CORE_LIB_GPR_ARENA_H
+
+#include <stddef.h>
+
+typedef struct gpr_arena gpr_arena;
+
+// Create an arena, with \a initial_size bytes in the first allocated buffer
+gpr_arena* gpr_arena_create(size_t initial_size);
+// Allocate \a size bytes from the arena
+void* gpr_arena_alloc(gpr_arena* arena, size_t size);
+// Destroy an arena, returning the total number of bytes allocated
+size_t gpr_arena_destroy(gpr_arena* arena);
+
+#endif /* GRPC_CORE_LIB_GPR_ARENA_H */
diff --git a/src/core/lib/gpr/atm.cc b/src/core/lib/gpr/atm.cc
new file mode 100644
index 0000000000..15bfe52d64
--- /dev/null
+++ b/src/core/lib/gpr/atm.cc
@@ -0,0 +1,32 @@
+/*
+ *
+ * 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 <grpc/support/atm.h>
+#include <grpc/support/useful.h>
+
+gpr_atm gpr_atm_no_barrier_clamped_add(gpr_atm* value, gpr_atm delta,
+                                       gpr_atm min, gpr_atm max) {
+  gpr_atm current_value;
+  gpr_atm new_value;
+  do {
+    current_value = gpr_atm_no_barrier_load(value);
+    new_value = GPR_CLAMP(current_value + delta, min, max);
+    if (new_value == current_value) break;
+  } while (!gpr_atm_no_barrier_cas(value, current_value, new_value));
+  return new_value;
+}
diff --git a/src/core/lib/gpr/avl.cc b/src/core/lib/gpr/avl.cc
new file mode 100644
index 0000000000..0b67a21f2f
--- /dev/null
+++ b/src/core/lib/gpr/avl.cc
@@ -0,0 +1,300 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/avl.h>
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
+
+gpr_avl gpr_avl_create(const gpr_avl_vtable* vtable) {
+  gpr_avl out;
+  out.vtable = vtable;
+  out.root = nullptr;
+  return out;
+}
+
+static gpr_avl_node* ref_node(gpr_avl_node* node) {
+  if (node) {
+    gpr_ref(&node->refs);
+  }
+  return node;
+}
+
+static void unref_node(const gpr_avl_vtable* vtable, gpr_avl_node* node,
+                       void* user_data) {
+  if (node == nullptr) {
+    return;
+  }
+  if (gpr_unref(&node->refs)) {
+    vtable->destroy_key(node->key, user_data);
+    vtable->destroy_value(node->value, user_data);
+    unref_node(vtable, node->left, user_data);
+    unref_node(vtable, node->right, user_data);
+    gpr_free(node);
+  }
+}
+
+static long node_height(gpr_avl_node* node) {
+  return node == nullptr ? 0 : node->height;
+}
+
+#ifndef NDEBUG
+static long calculate_height(gpr_avl_node* node) {
+  return node == nullptr ? 0
+                         : 1 + GPR_MAX(calculate_height(node->left),
+                                       calculate_height(node->right));
+}
+
+static gpr_avl_node* assert_invariants(gpr_avl_node* n) {
+  if (n == nullptr) return nullptr;
+  assert_invariants(n->left);
+  assert_invariants(n->right);
+  assert(calculate_height(n) == n->height);
+  assert(labs(node_height(n->left) - node_height(n->right)) <= 1);
+  return n;
+}
+#else
+static gpr_avl_node* assert_invariants(gpr_avl_node* n) { return n; }
+#endif
+
+gpr_avl_node* new_node(void* key, void* value, gpr_avl_node* left,
+                       gpr_avl_node* right) {
+  gpr_avl_node* node = (gpr_avl_node*)gpr_malloc(sizeof(*node));
+  gpr_ref_init(&node->refs, 1);
+  node->key = key;
+  node->value = value;
+  node->left = assert_invariants(left);
+  node->right = assert_invariants(right);
+  node->height = 1 + GPR_MAX(node_height(left), node_height(right));
+  return node;
+}
+
+static gpr_avl_node* get(const gpr_avl_vtable* vtable, gpr_avl_node* node,
+                         void* key, void* user_data) {
+  long cmp;
+
+  if (node == nullptr) {
+    return nullptr;
+  }
+
+  cmp = vtable->compare_keys(node->key, key, user_data);
+  if (cmp == 0) {
+    return node;
+  } else if (cmp > 0) {
+    return get(vtable, node->left, key, user_data);
+  } else {
+    return get(vtable, node->right, key, user_data);
+  }
+}
+
+void* gpr_avl_get(gpr_avl avl, void* key, void* user_data) {
+  gpr_avl_node* node = get(avl.vtable, avl.root, key, user_data);
+  return node ? node->value : nullptr;
+}
+
+int gpr_avl_maybe_get(gpr_avl avl, void* key, void** value, void* user_data) {
+  gpr_avl_node* node = get(avl.vtable, avl.root, key, user_data);
+  if (node != nullptr) {
+    *value = node->value;
+    return 1;
+  }
+  return 0;
+}
+
+static gpr_avl_node* rotate_left(const gpr_avl_vtable* vtable, void* key,
+                                 void* value, gpr_avl_node* left,
+                                 gpr_avl_node* right, void* user_data) {
+  gpr_avl_node* n = new_node(vtable->copy_key(right->key, user_data),
+                             vtable->copy_value(right->value, user_data),
+                             new_node(key, value, left, ref_node(right->left)),
+                             ref_node(right->right));
+  unref_node(vtable, right, user_data);
+  return n;
+}
+
+static gpr_avl_node* rotate_right(const gpr_avl_vtable* vtable, void* key,
+                                  void* value, gpr_avl_node* left,
+                                  gpr_avl_node* right, void* user_data) {
+  gpr_avl_node* n =
+      new_node(vtable->copy_key(left->key, user_data),
+               vtable->copy_value(left->value, user_data), ref_node(left->left),
+               new_node(key, value, ref_node(left->right), right));
+  unref_node(vtable, left, user_data);
+  return n;
+}
+
+static gpr_avl_node* rotate_left_right(const gpr_avl_vtable* vtable, void* key,
+                                       void* value, gpr_avl_node* left,
+                                       gpr_avl_node* right, void* user_data) {
+  /* rotate_right(..., rotate_left(left), right) */
+  gpr_avl_node* n =
+      new_node(vtable->copy_key(left->right->key, user_data),
+               vtable->copy_value(left->right->value, user_data),
+               new_node(vtable->copy_key(left->key, user_data),
+                        vtable->copy_value(left->value, user_data),
+                        ref_node(left->left), ref_node(left->right->left)),
+               new_node(key, value, ref_node(left->right->right), right));
+  unref_node(vtable, left, user_data);
+  return n;
+}
+
+static gpr_avl_node* rotate_right_left(const gpr_avl_vtable* vtable, void* key,
+                                       void* value, gpr_avl_node* left,
+                                       gpr_avl_node* right, void* user_data) {
+  /* rotate_left(..., left, rotate_right(right)) */
+  gpr_avl_node* n =
+      new_node(vtable->copy_key(right->left->key, user_data),
+               vtable->copy_value(right->left->value, user_data),
+               new_node(key, value, left, ref_node(right->left->left)),
+               new_node(vtable->copy_key(right->key, user_data),
+                        vtable->copy_value(right->value, user_data),
+                        ref_node(right->left->right), ref_node(right->right)));
+  unref_node(vtable, right, user_data);
+  return n;
+}
+
+static gpr_avl_node* rebalance(const gpr_avl_vtable* vtable, void* key,
+                               void* value, gpr_avl_node* left,
+                               gpr_avl_node* right, void* user_data) {
+  switch (node_height(left) - node_height(right)) {
+    case 2:
+      if (node_height(left->left) - node_height(left->right) == -1) {
+        return assert_invariants(
+            rotate_left_right(vtable, key, value, left, right, user_data));
+      } else {
+        return assert_invariants(
+            rotate_right(vtable, key, value, left, right, user_data));
+      }
+    case -2:
+      if (node_height(right->left) - node_height(right->right) == 1) {
+        return assert_invariants(
+            rotate_right_left(vtable, key, value, left, right, user_data));
+      } else {
+        return assert_invariants(
+            rotate_left(vtable, key, value, left, right, user_data));
+      }
+    default:
+      return assert_invariants(new_node(key, value, left, right));
+  }
+}
+
+static gpr_avl_node* add_key(const gpr_avl_vtable* vtable, gpr_avl_node* node,
+                             void* key, void* value, void* user_data) {
+  long cmp;
+  if (node == nullptr) {
+    return new_node(key, value, nullptr, nullptr);
+  }
+  cmp = vtable->compare_keys(node->key, key, user_data);
+  if (cmp == 0) {
+    return new_node(key, value, ref_node(node->left), ref_node(node->right));
+  } else if (cmp > 0) {
+    return rebalance(vtable, vtable->copy_key(node->key, user_data),
+                     vtable->copy_value(node->value, user_data),
+                     add_key(vtable, node->left, key, value, user_data),
+                     ref_node(node->right), user_data);
+  } else {
+    return rebalance(
+        vtable, vtable->copy_key(node->key, user_data),
+        vtable->copy_value(node->value, user_data), ref_node(node->left),
+        add_key(vtable, node->right, key, value, user_data), user_data);
+  }
+}
+
+gpr_avl gpr_avl_add(gpr_avl avl, void* key, void* value, void* user_data) {
+  gpr_avl_node* old_root = avl.root;
+  avl.root = add_key(avl.vtable, avl.root, key, value, user_data);
+  assert_invariants(avl.root);
+  unref_node(avl.vtable, old_root, user_data);
+  return avl;
+}
+
+static gpr_avl_node* in_order_head(gpr_avl_node* node) {
+  while (node->left != nullptr) {
+    node = node->left;
+  }
+  return node;
+}
+
+static gpr_avl_node* in_order_tail(gpr_avl_node* node) {
+  while (node->right != nullptr) {
+    node = node->right;
+  }
+  return node;
+}
+
+static gpr_avl_node* remove_key(const gpr_avl_vtable* vtable,
+                                gpr_avl_node* node, void* key,
+                                void* user_data) {
+  long cmp;
+  if (node == nullptr) {
+    return nullptr;
+  }
+  cmp = vtable->compare_keys(node->key, key, user_data);
+  if (cmp == 0) {
+    if (node->left == nullptr) {
+      return ref_node(node->right);
+    } else if (node->right == nullptr) {
+      return ref_node(node->left);
+    } else if (node->left->height < node->right->height) {
+      gpr_avl_node* h = in_order_head(node->right);
+      return rebalance(
+          vtable, vtable->copy_key(h->key, user_data),
+          vtable->copy_value(h->value, user_data), ref_node(node->left),
+          remove_key(vtable, node->right, h->key, user_data), user_data);
+    } else {
+      gpr_avl_node* h = in_order_tail(node->left);
+      return rebalance(vtable, vtable->copy_key(h->key, user_data),
+                       vtable->copy_value(h->value, user_data),
+                       remove_key(vtable, node->left, h->key, user_data),
+                       ref_node(node->right), user_data);
+    }
+  } else if (cmp > 0) {
+    return rebalance(vtable, vtable->copy_key(node->key, user_data),
+                     vtable->copy_value(node->value, user_data),
+                     remove_key(vtable, node->left, key, user_data),
+                     ref_node(node->right), user_data);
+  } else {
+    return rebalance(
+        vtable, vtable->copy_key(node->key, user_data),
+        vtable->copy_value(node->value, user_data), ref_node(node->left),
+        remove_key(vtable, node->right, key, user_data), user_data);
+  }
+}
+
+gpr_avl gpr_avl_remove(gpr_avl avl, void* key, void* user_data) {
+  gpr_avl_node* old_root = avl.root;
+  avl.root = remove_key(avl.vtable, avl.root, key, user_data);
+  assert_invariants(avl.root);
+  unref_node(avl.vtable, old_root, user_data);
+  return avl;
+}
+
+gpr_avl gpr_avl_ref(gpr_avl avl, void* user_data) {
+  ref_node(avl.root);
+  return avl;
+}
+
+void gpr_avl_unref(gpr_avl avl, void* user_data) {
+  unref_node(avl.vtable, avl.root, user_data);
+}
+
+int gpr_avl_is_empty(gpr_avl avl) { return avl.root == nullptr; }
diff --git a/src/core/lib/gpr/cmdline.cc b/src/core/lib/gpr/cmdline.cc
new file mode 100644
index 0000000000..4118f9a72a
--- /dev/null
+++ b/src/core/lib/gpr/cmdline.cc
@@ -0,0 +1,330 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/cmdline.h>
+
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include "src/core/lib/gpr/string.h"
+
+typedef enum { ARGTYPE_INT, ARGTYPE_BOOL, ARGTYPE_STRING } argtype;
+
+typedef struct arg {
+  const char* name;
+  const char* help;
+  argtype type;
+  void* value;
+  struct arg* next;
+} arg;
+
+struct gpr_cmdline {
+  const char* description;
+  arg* args;
+  const char* argv0;
+
+  const char* extra_arg_name;
+  const char* extra_arg_help;
+  void (*extra_arg)(void* user_data, const char* arg);
+  void* extra_arg_user_data;
+
+  int (*state)(gpr_cmdline* cl, char* arg);
+  arg* cur_arg;
+
+  int survive_failure;
+};
+
+static int normal_state(gpr_cmdline* cl, char* arg);
+
+gpr_cmdline* gpr_cmdline_create(const char* description) {
+  gpr_cmdline* cl = (gpr_cmdline*)gpr_zalloc(sizeof(gpr_cmdline));
+
+  cl->description = description;
+  cl->state = normal_state;
+
+  return cl;
+}
+
+void gpr_cmdline_set_survive_failure(gpr_cmdline* cl) {
+  cl->survive_failure = 1;
+}
+
+void gpr_cmdline_destroy(gpr_cmdline* cl) {
+  while (cl->args) {
+    arg* a = cl->args;
+    cl->args = a->next;
+    gpr_free(a);
+  }
+  gpr_free(cl);
+}
+
+static void add_arg(gpr_cmdline* cl, const char* name, const char* help,
+                    argtype type, void* value) {
+  arg* a;
+
+  for (a = cl->args; a; a = a->next) {
+    GPR_ASSERT(0 != strcmp(a->name, name));
+  }
+
+  a = (arg*)gpr_zalloc(sizeof(arg));
+  a->name = name;
+  a->help = help;
+  a->type = type;
+  a->value = value;
+  a->next = cl->args;
+  cl->args = a;
+}
+
+void gpr_cmdline_add_int(gpr_cmdline* cl, const char* name, const char* help,
+                         int* value) {
+  add_arg(cl, name, help, ARGTYPE_INT, value);
+}
+
+void gpr_cmdline_add_flag(gpr_cmdline* cl, const char* name, const char* help,
+                          int* value) {
+  add_arg(cl, name, help, ARGTYPE_BOOL, value);
+}
+
+void gpr_cmdline_add_string(gpr_cmdline* cl, const char* name, const char* help,
+                            const char** value) {
+  add_arg(cl, name, help, ARGTYPE_STRING, value);
+}
+
+void gpr_cmdline_on_extra_arg(
+    gpr_cmdline* cl, const char* name, const char* help,
+    void (*on_extra_arg)(void* user_data, const char* arg), void* user_data) {
+  GPR_ASSERT(!cl->extra_arg);
+  GPR_ASSERT(on_extra_arg);
+
+  cl->extra_arg = on_extra_arg;
+  cl->extra_arg_user_data = user_data;
+  cl->extra_arg_name = name;
+  cl->extra_arg_help = help;
+}
+
+/* recursively descend argument list, adding the last element
+   to s first - so that arguments are added in the order they were
+   added to the list by api calls */
+static void add_args_to_usage(gpr_strvec* s, arg* a) {
+  char* tmp;
+
+  if (!a) return;
+  add_args_to_usage(s, a->next);
+
+  switch (a->type) {
+    case ARGTYPE_BOOL:
+      gpr_asprintf(&tmp, " [--%s|--no-%s]", a->name, a->name);
+      gpr_strvec_add(s, tmp);
+      break;
+    case ARGTYPE_STRING:
+      gpr_asprintf(&tmp, " [--%s=string]", a->name);
+      gpr_strvec_add(s, tmp);
+      break;
+    case ARGTYPE_INT:
+      gpr_asprintf(&tmp, " [--%s=int]", a->name);
+      gpr_strvec_add(s, tmp);
+      break;
+  }
+}
+
+char* gpr_cmdline_usage_string(gpr_cmdline* cl, const char* argv0) {
+  /* TODO(ctiller): make this prettier */
+  gpr_strvec s;
+  char* tmp;
+  const char* name = strrchr(argv0, '/');
+
+  if (name) {
+    name++;
+  } else {
+    name = argv0;
+  }
+
+  gpr_strvec_init(&s);
+
+  gpr_asprintf(&tmp, "Usage: %s", name);
+  gpr_strvec_add(&s, tmp);
+  add_args_to_usage(&s, cl->args);
+  if (cl->extra_arg) {
+    gpr_asprintf(&tmp, " [%s...]", cl->extra_arg_name);
+    gpr_strvec_add(&s, tmp);
+  }
+  gpr_strvec_add(&s, gpr_strdup("\n"));
+
+  tmp = gpr_strvec_flatten(&s, nullptr);
+  gpr_strvec_destroy(&s);
+  return tmp;
+}
+
+static int print_usage_and_die(gpr_cmdline* cl) {
+  char* usage = gpr_cmdline_usage_string(cl, cl->argv0);
+  fprintf(stderr, "%s", usage);
+  gpr_free(usage);
+  if (!cl->survive_failure) {
+    exit(1);
+  }
+  return 0;
+}
+
+static int extra_state(gpr_cmdline* cl, char* str) {
+  if (!cl->extra_arg) {
+    return print_usage_and_die(cl);
+  }
+  cl->extra_arg(cl->extra_arg_user_data, str);
+  return 1;
+}
+
+static arg* find_arg(gpr_cmdline* cl, char* name) {
+  arg* a;
+
+  for (a = cl->args; a; a = a->next) {
+    if (0 == strcmp(a->name, name)) {
+      break;
+    }
+  }
+
+  if (!a) {
+    fprintf(stderr, "Unknown argument: %s\n", name);
+    return nullptr;
+  }
+
+  return a;
+}
+
+static int value_state(gpr_cmdline* cl, char* str) {
+  long intval;
+  char* end;
+
+  GPR_ASSERT(cl->cur_arg);
+
+  switch (cl->cur_arg->type) {
+    case ARGTYPE_INT:
+      intval = strtol(str, &end, 0);
+      if (*end || intval < INT_MIN || intval > INT_MAX) {
+        fprintf(stderr, "expected integer, got '%s' for %s\n", str,
+                cl->cur_arg->name);
+        return print_usage_and_die(cl);
+      }
+      *(int*)cl->cur_arg->value = (int)intval;
+      break;
+    case ARGTYPE_BOOL:
+      if (0 == strcmp(str, "1") || 0 == strcmp(str, "true")) {
+        *(int*)cl->cur_arg->value = 1;
+      } else if (0 == strcmp(str, "0") || 0 == strcmp(str, "false")) {
+        *(int*)cl->cur_arg->value = 0;
+      } else {
+        fprintf(stderr, "expected boolean, got '%s' for %s\n", str,
+                cl->cur_arg->name);
+        return print_usage_and_die(cl);
+      }
+      break;
+    case ARGTYPE_STRING:
+      *(char**)cl->cur_arg->value = str;
+      break;
+  }
+
+  cl->state = normal_state;
+  return 1;
+}
+
+static int normal_state(gpr_cmdline* cl, char* str) {
+  char* eq = nullptr;
+  char* tmp = nullptr;
+  char* arg_name = nullptr;
+  int r = 1;
+
+  if (0 == strcmp(str, "-help") || 0 == strcmp(str, "--help") ||
+      0 == strcmp(str, "-h")) {
+    return print_usage_and_die(cl);
+  }
+
+  cl->cur_arg = nullptr;
+
+  if (str[0] == '-') {
+    if (str[1] == '-') {
+      if (str[2] == 0) {
+        /* handle '--' to move to just extra args */
+        cl->state = extra_state;
+        return 1;
+      }
+      str += 2;
+    } else {
+      str += 1;
+    }
+    /* first byte of str is now past the leading '-' or '--' */
+    if (str[0] == 'n' && str[1] == 'o' && str[2] == '-') {
+      /* str is of the form '--no-foo' - it's a flag disable */
+      str += 3;
+      cl->cur_arg = find_arg(cl, str);
+      if (cl->cur_arg == nullptr) {
+        return print_usage_and_die(cl);
+      }
+      if (cl->cur_arg->type != ARGTYPE_BOOL) {
+        fprintf(stderr, "%s is not a flag argument\n", str);
+        return print_usage_and_die(cl);
+      }
+      *(int*)cl->cur_arg->value = 0;
+      return 1; /* early out */
+    }
+    eq = strchr(str, '=');
+    if (eq != nullptr) {
+      /* copy the string into a temp buffer and extract the name */
+      tmp = arg_name = (char*)gpr_malloc((size_t)(eq - str + 1));
+      memcpy(arg_name, str, (size_t)(eq - str));
+      arg_name[eq - str] = 0;
+    } else {
+      arg_name = str;
+    }
+    cl->cur_arg = find_arg(cl, arg_name);
+    if (cl->cur_arg == nullptr) {
+      return print_usage_and_die(cl);
+    }
+    if (eq != nullptr) {
+      /* str was of the type --foo=value, parse the value */
+      r = value_state(cl, eq + 1);
+    } else if (cl->cur_arg->type != ARGTYPE_BOOL) {
+      /* flag types don't have a '--foo value' variant, other types do */
+      cl->state = value_state;
+    } else {
+      /* flag parameter: just set the value */
+      *(int*)cl->cur_arg->value = 1;
+    }
+  } else {
+    r = extra_state(cl, str);
+  }
+
+  gpr_free(tmp);
+  return r;
+}
+
+int gpr_cmdline_parse(gpr_cmdline* cl, int argc, char** argv) {
+  int i;
+
+  GPR_ASSERT(argc >= 1);
+  cl->argv0 = argv[0];
+
+  for (i = 1; i < argc; i++) {
+    if (!cl->state(cl, argv[i])) {
+      return 0;
+    }
+  }
+  return 1;
+}
diff --git a/src/core/lib/gpr/cpu_iphone.cc b/src/core/lib/gpr/cpu_iphone.cc
new file mode 100644
index 0000000000..2847e03ba5
--- /dev/null
+++ b/src/core/lib/gpr/cpu_iphone.cc
@@ -0,0 +1,36 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include <grpc/support/cpu.h>
+
+#ifdef GPR_CPU_IPHONE
+
+/* Probably 2 instead of 1, but see comment on gpr_cpu_current_cpu. */
+unsigned gpr_cpu_num_cores(void) { return 1; }
+
+/* Most code that's using this is using it to shard across work queues. So
+   unless profiling shows it's a problem or there appears a way to detect the
+   currently running CPU core, let's have it shard the default way.
+   Note that the interface in cpu.h lets gpr_cpu_num_cores return 0, but doing
+   it makes it impossible for gpr_cpu_current_cpu to satisfy its stated range,
+   and some code might be relying on it. */
+unsigned gpr_cpu_current_cpu(void) { return 0; }
+
+#endif /* GPR_CPU_IPHONE */
diff --git a/src/core/lib/gpr/cpu_linux.cc b/src/core/lib/gpr/cpu_linux.cc
new file mode 100644
index 0000000000..21b1a71dc9
--- /dev/null
+++ b/src/core/lib/gpr/cpu_linux.cc
@@ -0,0 +1,78 @@
+/*
+ *
+ * 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 _GNU_SOURCE
+#define _GNU_SOURCE
+#endif /* _GNU_SOURCE */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_CPU_LINUX
+
+#include <errno.h>
+#include <sched.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <grpc/support/cpu.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+
+static int ncpus = 0;
+
+static void init_num_cpus() {
+#ifndef GPR_MUSL_LIBC_COMPAT
+  if (sched_getcpu() < 0) {
+    gpr_log(GPR_ERROR, "Error determining current CPU: %s\n", strerror(errno));
+    ncpus = 1;
+    return;
+  }
+#endif
+  /* This must be signed. sysconf returns -1 when the number cannot be
+     determined */
+  ncpus = (int)sysconf(_SC_NPROCESSORS_ONLN);
+  if (ncpus < 1) {
+    gpr_log(GPR_ERROR, "Cannot determine number of CPUs: assuming 1");
+    ncpus = 1;
+  }
+}
+
+unsigned gpr_cpu_num_cores(void) {
+  static gpr_once once = GPR_ONCE_INIT;
+  gpr_once_init(&once, init_num_cpus);
+  return (unsigned)ncpus;
+}
+
+unsigned gpr_cpu_current_cpu(void) {
+#ifdef GPR_MUSL_LIBC_COMPAT
+  // sched_getcpu() is undefined on musl
+  return 0;
+#else
+  if (gpr_cpu_num_cores() == 1) {
+    return 0;
+  }
+  int cpu = sched_getcpu();
+  if (cpu < 0) {
+    gpr_log(GPR_ERROR, "Error determining current CPU: %s\n", strerror(errno));
+    return 0;
+  }
+  return (unsigned)cpu;
+#endif
+}
+
+#endif /* GPR_CPU_LINUX */
diff --git a/src/core/lib/gpr/cpu_posix.cc b/src/core/lib/gpr/cpu_posix.cc
new file mode 100644
index 0000000000..bca14a0c12
--- /dev/null
+++ b/src/core/lib/gpr/cpu_posix.cc
@@ -0,0 +1,80 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#if defined(GPR_CPU_POSIX)
+
+#include <errno.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/cpu.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/useful.h>
+
+static long ncpus = 0;
+
+static pthread_key_t thread_id_key;
+
+static void init_ncpus() {
+  ncpus = sysconf(_SC_NPROCESSORS_ONLN);
+  if (ncpus < 1 || ncpus > INT32_MAX) {
+    gpr_log(GPR_ERROR, "Cannot determine number of CPUs: assuming 1");
+    ncpus = 1;
+  }
+}
+
+unsigned gpr_cpu_num_cores(void) {
+  static gpr_once once = GPR_ONCE_INIT;
+  gpr_once_init(&once, init_ncpus);
+  return (unsigned)ncpus;
+}
+
+static void delete_thread_id(void* value) {
+  if (value) {
+    gpr_free(value);
+  }
+}
+
+static void init_thread_id_key(void) {
+  pthread_key_create(&thread_id_key, delete_thread_id);
+}
+
+unsigned gpr_cpu_current_cpu(void) {
+  /* NOTE: there's no way I know to return the actual cpu index portably...
+     most code that's using this is using it to shard across work queues though,
+     so here we use thread identity instead to achieve a similar though not
+     identical effect */
+  static gpr_once once = GPR_ONCE_INIT;
+  gpr_once_init(&once, init_thread_id_key);
+
+  unsigned int* thread_id =
+      static_cast<unsigned int*>(pthread_getspecific(thread_id_key));
+  if (thread_id == nullptr) {
+    thread_id = static_cast<unsigned int*>(gpr_malloc(sizeof(unsigned int)));
+    pthread_setspecific(thread_id_key, thread_id);
+  }
+
+  return (unsigned)GPR_HASH_POINTER(thread_id, gpr_cpu_num_cores());
+}
+
+#endif /* GPR_CPU_POSIX */
diff --git a/src/core/lib/gpr/cpu_windows.cc b/src/core/lib/gpr/cpu_windows.cc
new file mode 100644
index 0000000000..8d89453403
--- /dev/null
+++ b/src/core/lib/gpr/cpu_windows.cc
@@ -0,0 +1,33 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS
+#include <grpc/support/cpu.h>
+#include <grpc/support/log.h>
+
+unsigned gpr_cpu_num_cores(void) {
+  SYSTEM_INFO si;
+  GetSystemInfo(&si);
+  return si.dwNumberOfProcessors;
+}
+
+unsigned gpr_cpu_current_cpu(void) { return GetCurrentProcessorNumber(); }
+
+#endif /* GPR_WINDOWS */
diff --git a/src/core/lib/gpr/env.h b/src/core/lib/gpr/env.h
new file mode 100644
index 0000000000..7f35104be3
--- /dev/null
+++ b/src/core/lib/gpr/env.h
@@ -0,0 +1,41 @@
+/*
+ *
+ * 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_GPR_ENV_H
+#define GRPC_CORE_LIB_GPR_ENV_H
+
+#include <stdio.h>
+
+/* Env utility functions */
+
+/* Gets the environment variable value with the specified name.
+   Returns a newly allocated string. It is the responsability of the caller to
+   gpr_free the return value if not NULL (which means that the environment
+   variable exists). */
+char* gpr_getenv(const char* name);
+
+/* Sets the the environment with the specified name to the specified value. */
+void gpr_setenv(const char* name, const char* value);
+
+/* This is a version of gpr_getenv that does not produce any output if it has to
+   use an insecure version of the function. It is ONLY to be used to solve the
+   problem in which we need to check an env variable to configure the verbosity
+   level of logging. So DO NOT USE THIS. */
+const char* gpr_getenv_silent(const char* name, char** dst);
+
+#endif /* GRPC_CORE_LIB_GPR_ENV_H */
diff --git a/src/core/lib/gpr/env_linux.cc b/src/core/lib/gpr/env_linux.cc
new file mode 100644
index 0000000000..17902c3d0b
--- /dev/null
+++ b/src/core/lib/gpr/env_linux.cc
@@ -0,0 +1,82 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* for secure_getenv. */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_LINUX_ENV
+
+#include "src/core/lib/gpr/env.h"
+
+#include <dlfcn.h>
+#include <features.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
+
+#include "src/core/lib/gpr/string.h"
+
+const char* gpr_getenv_silent(const char* name, char** dst) {
+  const char* insecure_func_used = nullptr;
+  char* result = nullptr;
+#if defined(GPR_BACKWARDS_COMPATIBILITY_MODE)
+  typedef char* (*getenv_type)(const char*);
+  static getenv_type getenv_func = NULL;
+  /* Check to see which getenv variant is supported (go from most
+   * to least secure) */
+  const char* names[] = {"secure_getenv", "__secure_getenv", "getenv"};
+  for (size_t i = 0; getenv_func == NULL && i < GPR_ARRAY_SIZE(names); i++) {
+    getenv_func = (getenv_type)dlsym(RTLD_DEFAULT, names[i]);
+    if (getenv_func != NULL && strstr(names[i], "secure") == NULL) {
+      insecure_func_used = names[i];
+    }
+  }
+  result = getenv_func(name);
+#elif __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 17)
+  result = secure_getenv(name);
+#else
+  result = getenv(name);
+  insecure_func_used = "getenv";
+#endif
+  *dst = result == nullptr ? result : gpr_strdup(result);
+  return insecure_func_used;
+}
+
+char* gpr_getenv(const char* name) {
+  char* result = nullptr;
+  const char* insecure_func_used = gpr_getenv_silent(name, &result);
+  if (insecure_func_used != nullptr) {
+    gpr_log(GPR_DEBUG, "Warning: insecure environment read function '%s' used",
+            insecure_func_used);
+  }
+  return result;
+}
+
+void gpr_setenv(const char* name, const char* value) {
+  int res = setenv(name, value, 1);
+  GPR_ASSERT(res == 0);
+}
+
+#endif /* GPR_LINUX_ENV */
diff --git a/src/core/lib/gpr/env_posix.cc b/src/core/lib/gpr/env_posix.cc
new file mode 100644
index 0000000000..599f85aa72
--- /dev/null
+++ b/src/core/lib/gpr/env_posix.cc
@@ -0,0 +1,47 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_ENV
+
+#include "src/core/lib/gpr/env.h"
+
+#include <stdlib.h>
+
+#include <grpc/support/log.h>
+
+#include <grpc/support/string_util.h>
+#include "src/core/lib/gpr/string.h"
+
+const char* gpr_getenv_silent(const char* name, char** dst) {
+  *dst = gpr_getenv(name);
+  return nullptr;
+}
+
+char* gpr_getenv(const char* name) {
+  char* result = getenv(name);
+  return result == nullptr ? result : gpr_strdup(result);
+}
+
+void gpr_setenv(const char* name, const char* value) {
+  int res = setenv(name, value, 1);
+  GPR_ASSERT(res == 0);
+}
+
+#endif /* GPR_POSIX_ENV */
diff --git a/src/core/lib/gpr/env_windows.cc b/src/core/lib/gpr/env_windows.cc
new file mode 100644
index 0000000000..9ca1e02d03
--- /dev/null
+++ b/src/core/lib/gpr/env_windows.cc
@@ -0,0 +1,72 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS_ENV
+
+#include <windows.h>
+
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gpr/string_windows.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+
+const char* gpr_getenv_silent(const char* name, char** dst) {
+  *dst = gpr_getenv(name);
+  return NULL;
+}
+
+char* gpr_getenv(const char* name) {
+  char* result = NULL;
+  DWORD size;
+  LPTSTR tresult = NULL;
+  LPTSTR tname = gpr_char_to_tchar(name);
+  DWORD ret;
+
+  ret = GetEnvironmentVariable(tname, NULL, 0);
+  if (ret == 0) {
+    gpr_free(tname);
+    return NULL;
+  }
+  size = ret * (DWORD)sizeof(TCHAR);
+  tresult = (LPTSTR)gpr_malloc(size);
+  ret = GetEnvironmentVariable(tname, tresult, size);
+  gpr_free(tname);
+  if (ret == 0) {
+    gpr_free(tresult);
+    return NULL;
+  }
+  result = gpr_tchar_to_char(tresult);
+  gpr_free(tresult);
+  return result;
+}
+
+void gpr_setenv(const char* name, const char* value) {
+  LPTSTR tname = gpr_char_to_tchar(name);
+  LPTSTR tvalue = gpr_char_to_tchar(value);
+  BOOL res = SetEnvironmentVariable(tname, tvalue);
+  gpr_free(tname);
+  gpr_free(tvalue);
+  GPR_ASSERT(res);
+}
+
+#endif /* GPR_WINDOWS_ENV */
diff --git a/src/core/lib/gpr/fork.cc b/src/core/lib/gpr/fork.cc
new file mode 100644
index 0000000000..c47e686378
--- /dev/null
+++ b/src/core/lib/gpr/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/gpr/fork.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/useful.h>
+
+#include "src/core/lib/gpr/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 != nullptr) {
+    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/gpr/fork.h b/src/core/lib/gpr/fork.h
new file mode 100644
index 0000000000..94c61bb836
--- /dev/null
+++ b/src/core/lib/gpr/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_GPR_FORK_H
+#define GRPC_CORE_LIB_GPR_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_GPR_FORK_H */
diff --git a/src/core/lib/gpr/host_port.cc b/src/core/lib/gpr/host_port.cc
new file mode 100644
index 0000000000..29178279d3
--- /dev/null
+++ b/src/core/lib/gpr/host_port.cc
@@ -0,0 +1,95 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/host_port.h>
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include "src/core/lib/gpr/string.h"
+
+int gpr_join_host_port(char** out, const char* host, int port) {
+  if (host[0] != '[' && strchr(host, ':') != nullptr) {
+    /* IPv6 literals must be enclosed in brackets. */
+    return gpr_asprintf(out, "[%s]:%d", host, port);
+  } else {
+    /* Ordinary non-bracketed host:port. */
+    return gpr_asprintf(out, "%s:%d", host, port);
+  }
+}
+
+int gpr_split_host_port(const char* name, char** host, char** port) {
+  const char* host_start;
+  size_t host_len;
+  const char* port_start;
+
+  *host = nullptr;
+  *port = nullptr;
+
+  if (name[0] == '[') {
+    /* Parse a bracketed host, typically an IPv6 literal. */
+    const char* rbracket = strchr(name, ']');
+    if (rbracket == nullptr) {
+      /* Unmatched [ */
+      return 0;
+    }
+    if (rbracket[1] == '\0') {
+      /* ]<end> */
+      port_start = nullptr;
+    } else if (rbracket[1] == ':') {
+      /* ]:<port?> */
+      port_start = rbracket + 2;
+    } else {
+      /* ]<invalid> */
+      return 0;
+    }
+    host_start = name + 1;
+    host_len = (size_t)(rbracket - host_start);
+    if (memchr(host_start, ':', host_len) == nullptr) {
+      /* Require all bracketed hosts to contain a colon, because a hostname or
+         IPv4 address should never use brackets. */
+      return 0;
+    }
+  } else {
+    const char* colon = strchr(name, ':');
+    if (colon != nullptr && strchr(colon + 1, ':') == nullptr) {
+      /* Exactly 1 colon.  Split into host:port. */
+      host_start = name;
+      host_len = (size_t)(colon - name);
+      port_start = colon + 1;
+    } else {
+      /* 0 or 2+ colons.  Bare hostname or IPv6 litearal. */
+      host_start = name;
+      host_len = strlen(name);
+      port_start = nullptr;
+    }
+  }
+
+  /* Allocate return values. */
+  *host = (char*)gpr_malloc(host_len + 1);
+  memcpy(*host, host_start, host_len);
+  (*host)[host_len] = '\0';
+
+  if (port_start != nullptr) {
+    *port = gpr_strdup(port_start);
+  }
+
+  return 1;
+}
diff --git a/src/core/lib/gpr/log.cc b/src/core/lib/gpr/log.cc
new file mode 100644
index 0000000000..19c0f6c34d
--- /dev/null
+++ b/src/core/lib/gpr/log.cc
@@ -0,0 +1,94 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/atm.h>
+#include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
+
+#include <stdio.h>
+#include <string.h>
+
+void gpr_default_log(gpr_log_func_args* args);
+static gpr_atm g_log_func = (gpr_atm)gpr_default_log;
+static gpr_atm g_min_severity_to_print = GPR_LOG_VERBOSITY_UNSET;
+
+const char* gpr_log_severity_string(gpr_log_severity severity) {
+  switch (severity) {
+    case GPR_LOG_SEVERITY_DEBUG:
+      return "D";
+    case GPR_LOG_SEVERITY_INFO:
+      return "I";
+    case GPR_LOG_SEVERITY_ERROR:
+      return "E";
+  }
+  GPR_UNREACHABLE_CODE(return "UNKNOWN");
+}
+
+void gpr_log_message(const char* file, int line, gpr_log_severity severity,
+                     const char* message) {
+  if ((gpr_atm)severity < gpr_atm_no_barrier_load(&g_min_severity_to_print)) {
+    return;
+  }
+
+  gpr_log_func_args lfargs;
+  memset(&lfargs, 0, sizeof(lfargs));
+  lfargs.file = file;
+  lfargs.line = line;
+  lfargs.severity = severity;
+  lfargs.message = message;
+  ((gpr_log_func)gpr_atm_no_barrier_load(&g_log_func))(&lfargs);
+}
+
+void gpr_set_log_verbosity(gpr_log_severity min_severity_to_print) {
+  gpr_atm_no_barrier_store(&g_min_severity_to_print,
+                           (gpr_atm)min_severity_to_print);
+}
+
+void gpr_log_verbosity_init() {
+  char* verbosity = nullptr;
+  const char* insecure_getenv = gpr_getenv_silent("GRPC_VERBOSITY", &verbosity);
+
+  gpr_atm min_severity_to_print = GPR_LOG_SEVERITY_ERROR;
+  if (verbosity != nullptr) {
+    if (gpr_stricmp(verbosity, "DEBUG") == 0) {
+      min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_DEBUG;
+    } else if (gpr_stricmp(verbosity, "INFO") == 0) {
+      min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_INFO;
+    } else if (gpr_stricmp(verbosity, "ERROR") == 0) {
+      min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_ERROR;
+    }
+    gpr_free(verbosity);
+  }
+  if ((gpr_atm_no_barrier_load(&g_min_severity_to_print)) ==
+      GPR_LOG_VERBOSITY_UNSET) {
+    gpr_atm_no_barrier_store(&g_min_severity_to_print, min_severity_to_print);
+  }
+
+  if (insecure_getenv != nullptr) {
+    gpr_log(GPR_DEBUG, "Warning: insecure environment read function '%s' used",
+            insecure_getenv);
+  }
+}
+
+void gpr_set_log_function(gpr_log_func f) {
+  gpr_atm_no_barrier_store(&g_log_func, (gpr_atm)(f ? f : gpr_default_log));
+}
diff --git a/src/core/lib/gpr/log_android.cc b/src/core/lib/gpr/log_android.cc
new file mode 100644
index 0000000000..0d3ac0fe52
--- /dev/null
+++ b/src/core/lib/gpr/log_android.cc
@@ -0,0 +1,72 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_ANDROID
+
+#include <android/log.h>
+#include <grpc/support/log.h>
+#include <grpc/support/time.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+static android_LogPriority severity_to_log_priority(gpr_log_severity severity) {
+  switch (severity) {
+    case GPR_LOG_SEVERITY_DEBUG:
+      return ANDROID_LOG_DEBUG;
+    case GPR_LOG_SEVERITY_INFO:
+      return ANDROID_LOG_INFO;
+    case GPR_LOG_SEVERITY_ERROR:
+      return ANDROID_LOG_ERROR;
+  }
+  return ANDROID_LOG_DEFAULT;
+}
+
+void gpr_log(const char* file, int line, gpr_log_severity severity,
+             const char* format, ...) {
+  char* message = NULL;
+  va_list args;
+  va_start(args, format);
+  vasprintf(&message, format, args);
+  va_end(args);
+  gpr_log_message(file, line, severity, message);
+  free(message);
+}
+
+void gpr_default_log(gpr_log_func_args* args) {
+  const char* final_slash;
+  const char* display_file;
+  char* output = NULL;
+
+  final_slash = strrchr(args->file, '/');
+  if (final_slash == NULL)
+    display_file = args->file;
+  else
+    display_file = final_slash + 1;
+
+  asprintf(&output, "%s:%d] %s", display_file, args->line, args->message);
+
+  __android_log_write(severity_to_log_priority(args->severity), "GRPC", output);
+
+  /* allocated by asprintf => use free, not gpr_free */
+  free(output);
+}
+
+#endif /* GPR_ANDROID */
diff --git a/src/core/lib/gpr/log_linux.cc b/src/core/lib/gpr/log_linux.cc
new file mode 100644
index 0000000000..6b1f1c71e4
--- /dev/null
+++ b/src/core/lib/gpr/log_linux.cc
@@ -0,0 +1,92 @@
+/*
+ *
+ * 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 _POSIX_SOURCE
+#define _POSIX_SOURCE
+#endif
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_LINUX_LOG
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/time.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <time.h>
+#include <unistd.h>
+
+static long gettid(void) { return syscall(__NR_gettid); }
+
+void gpr_log(const char* file, int line, gpr_log_severity severity,
+             const char* format, ...) {
+  char* message = nullptr;
+  va_list args;
+  va_start(args, format);
+  if (vasprintf(&message, format, args) == -1) {
+    va_end(args);
+    return;
+  }
+  va_end(args);
+  gpr_log_message(file, line, severity, message);
+  /* message has been allocated by vasprintf above, and needs free */
+  free(message);
+}
+
+void gpr_default_log(gpr_log_func_args* args) {
+  const char* final_slash;
+  char* prefix;
+  const char* display_file;
+  char time_buffer[64];
+  time_t timer;
+  gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
+  struct tm tm;
+  static __thread long tid = 0;
+  if (tid == 0) tid = gettid();
+
+  timer = (time_t)now.tv_sec;
+  final_slash = strrchr(args->file, '/');
+  if (final_slash == nullptr)
+    display_file = args->file;
+  else
+    display_file = final_slash + 1;
+
+  if (!localtime_r(&timer, &tm)) {
+    strcpy(time_buffer, "error:localtime");
+  } else if (0 ==
+             strftime(time_buffer, sizeof(time_buffer), "%m%d %H:%M:%S", &tm)) {
+    strcpy(time_buffer, "error:strftime");
+  }
+
+  gpr_asprintf(&prefix, "%s%s.%09" PRId32 " %7ld %s:%d]",
+               gpr_log_severity_string(args->severity), time_buffer,
+               now.tv_nsec, tid, display_file, args->line);
+
+  fprintf(stderr, "%-60s %s\n", prefix, args->message);
+  gpr_free(prefix);
+}
+
+#endif /* GPR_LINUX_LOG */
diff --git a/src/core/lib/gpr/log_posix.cc b/src/core/lib/gpr/log_posix.cc
new file mode 100644
index 0000000000..6f93cdefcd
--- /dev/null
+++ b/src/core/lib/gpr/log_posix.cc
@@ -0,0 +1,90 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_LOG
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/time.h>
+#include <pthread.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+static intptr_t gettid(void) { return (intptr_t)pthread_self(); }
+
+void gpr_log(const char* file, int line, gpr_log_severity severity,
+             const char* format, ...) {
+  char buf[64];
+  char* allocated = nullptr;
+  char* message = nullptr;
+  int ret;
+  va_list args;
+  va_start(args, format);
+  ret = vsnprintf(buf, sizeof(buf), format, args);
+  va_end(args);
+  if (ret < 0) {
+    message = nullptr;
+  } else if ((size_t)ret <= sizeof(buf) - 1) {
+    message = buf;
+  } else {
+    message = allocated = (char*)gpr_malloc((size_t)ret + 1);
+    va_start(args, format);
+    vsnprintf(message, (size_t)(ret + 1), format, args);
+    va_end(args);
+  }
+  gpr_log_message(file, line, severity, message);
+  gpr_free(allocated);
+}
+
+void gpr_default_log(gpr_log_func_args* args) {
+  const char* final_slash;
+  const char* display_file;
+  char time_buffer[64];
+  time_t timer;
+  gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
+  struct tm tm;
+
+  timer = (time_t)now.tv_sec;
+  final_slash = strrchr(args->file, '/');
+  if (final_slash == nullptr)
+    display_file = args->file;
+  else
+    display_file = final_slash + 1;
+
+  if (!localtime_r(&timer, &tm)) {
+    strcpy(time_buffer, "error:localtime");
+  } else if (0 ==
+             strftime(time_buffer, sizeof(time_buffer), "%m%d %H:%M:%S", &tm)) {
+    strcpy(time_buffer, "error:strftime");
+  }
+
+  char* prefix;
+  gpr_asprintf(&prefix, "%s%s.%09d %7tu %s:%d]",
+               gpr_log_severity_string(args->severity), time_buffer,
+               (int)(now.tv_nsec), gettid(), display_file, args->line);
+
+  fprintf(stderr, "%-70s %s\n", prefix, args->message);
+  gpr_free(prefix);
+}
+
+#endif /* defined(GPR_POSIX_LOG) */
diff --git a/src/core/lib/gpr/log_windows.cc b/src/core/lib/gpr/log_windows.cc
new file mode 100644
index 0000000000..caaa973f5a
--- /dev/null
+++ b/src/core/lib/gpr/log_windows.cc
@@ -0,0 +1,97 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS_LOG
+
+#include <stdarg.h>
+#include <stdio.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/log_windows.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/time.h>
+
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gpr/string_windows.h"
+
+void gpr_log(const char* file, int line, gpr_log_severity severity,
+             const char* format, ...) {
+  char* message = NULL;
+  va_list args;
+  int ret;
+
+  /* Determine the length. */
+  va_start(args, format);
+  ret = _vscprintf(format, args);
+  va_end(args);
+  if (ret < 0) {
+    message = NULL;
+  } else {
+    /* Allocate a new buffer, with space for the NUL terminator. */
+    size_t strp_buflen = (size_t)ret + 1;
+    message = (char*)gpr_malloc(strp_buflen);
+
+    /* Print to the buffer. */
+    va_start(args, format);
+    ret = vsnprintf_s(message, strp_buflen, _TRUNCATE, format, args);
+    va_end(args);
+    if ((size_t)ret != strp_buflen - 1) {
+      /* This should never happen. */
+      gpr_free(message);
+      message = NULL;
+    }
+  }
+
+  gpr_log_message(file, line, severity, message);
+  gpr_free(message);
+}
+
+/* Simple starter implementation */
+void gpr_default_log(gpr_log_func_args* args) {
+  const char* final_slash;
+  const char* display_file;
+  char time_buffer[64];
+  time_t timer;
+  gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
+  struct tm tm;
+
+  timer = (time_t)now.tv_sec;
+  final_slash = strrchr(args->file, '\\');
+  if (final_slash == NULL)
+    display_file = args->file;
+  else
+    display_file = final_slash + 1;
+
+  if (localtime_s(&tm, &timer)) {
+    strcpy(time_buffer, "error:localtime");
+  } else if (0 ==
+             strftime(time_buffer, sizeof(time_buffer), "%m%d %H:%M:%S", &tm)) {
+    strcpy(time_buffer, "error:strftime");
+  }
+
+  fprintf(stderr, "%s%s.%09u %5lu %s:%d] %s\n",
+          gpr_log_severity_string(args->severity), time_buffer,
+          (int)(now.tv_nsec), GetCurrentThreadId(), display_file, args->line,
+          args->message);
+  fflush(stderr);
+}
+
+#endif /* GPR_WINDOWS_LOG */
diff --git a/src/core/lib/gpr/mpscq.cc b/src/core/lib/gpr/mpscq.cc
new file mode 100644
index 0000000000..34fc050a11
--- /dev/null
+++ b/src/core/lib/gpr/mpscq.cc
@@ -0,0 +1,114 @@
+/*
+ *
+ * Copyright 2016 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/mpscq.h"
+
+#include <grpc/support/log.h>
+
+void gpr_mpscq_init(gpr_mpscq* q) {
+  gpr_atm_no_barrier_store(&q->head, (gpr_atm)&q->stub);
+  q->tail = &q->stub;
+  gpr_atm_no_barrier_store(&q->stub.next, (gpr_atm)NULL);
+}
+
+void gpr_mpscq_destroy(gpr_mpscq* q) {
+  GPR_ASSERT(gpr_atm_no_barrier_load(&q->head) == (gpr_atm)&q->stub);
+  GPR_ASSERT(q->tail == &q->stub);
+}
+
+bool gpr_mpscq_push(gpr_mpscq* q, gpr_mpscq_node* n) {
+  gpr_atm_no_barrier_store(&n->next, (gpr_atm)NULL);
+  gpr_mpscq_node* prev =
+      (gpr_mpscq_node*)gpr_atm_full_xchg(&q->head, (gpr_atm)n);
+  gpr_atm_rel_store(&prev->next, (gpr_atm)n);
+  return prev == &q->stub;
+}
+
+gpr_mpscq_node* gpr_mpscq_pop(gpr_mpscq* q) {
+  bool empty;
+  return gpr_mpscq_pop_and_check_end(q, &empty);
+}
+
+gpr_mpscq_node* gpr_mpscq_pop_and_check_end(gpr_mpscq* q, bool* empty) {
+  gpr_mpscq_node* tail = q->tail;
+  gpr_mpscq_node* next = (gpr_mpscq_node*)gpr_atm_acq_load(&tail->next);
+  if (tail == &q->stub) {
+    // indicates the list is actually (ephemerally) empty
+    if (next == nullptr) {
+      *empty = true;
+      return nullptr;
+    }
+    q->tail = next;
+    tail = next;
+    next = (gpr_mpscq_node*)gpr_atm_acq_load(&tail->next);
+  }
+  if (next != nullptr) {
+    *empty = false;
+    q->tail = next;
+    return tail;
+  }
+  gpr_mpscq_node* head = (gpr_mpscq_node*)gpr_atm_acq_load(&q->head);
+  if (tail != head) {
+    *empty = false;
+    // indicates a retry is in order: we're still adding
+    return nullptr;
+  }
+  gpr_mpscq_push(q, &q->stub);
+  next = (gpr_mpscq_node*)gpr_atm_acq_load(&tail->next);
+  if (next != nullptr) {
+    q->tail = next;
+    return tail;
+  }
+  // indicates a retry is in order: we're still adding
+  *empty = false;
+  return nullptr;
+}
+
+void gpr_locked_mpscq_init(gpr_locked_mpscq* q) {
+  gpr_mpscq_init(&q->queue);
+  gpr_mu_init(&q->mu);
+}
+
+void gpr_locked_mpscq_destroy(gpr_locked_mpscq* q) {
+  gpr_mpscq_destroy(&q->queue);
+  gpr_mu_destroy(&q->mu);
+}
+
+bool gpr_locked_mpscq_push(gpr_locked_mpscq* q, gpr_mpscq_node* n) {
+  return gpr_mpscq_push(&q->queue, n);
+}
+
+gpr_mpscq_node* gpr_locked_mpscq_try_pop(gpr_locked_mpscq* q) {
+  if (gpr_mu_trylock(&q->mu)) {
+    gpr_mpscq_node* n = gpr_mpscq_pop(&q->queue);
+    gpr_mu_unlock(&q->mu);
+    return n;
+  }
+  return nullptr;
+}
+
+gpr_mpscq_node* gpr_locked_mpscq_pop(gpr_locked_mpscq* q) {
+  gpr_mu_lock(&q->mu);
+  bool empty = false;
+  gpr_mpscq_node* n;
+  do {
+    n = gpr_mpscq_pop_and_check_end(&q->queue, &empty);
+  } while (n == nullptr && !empty);
+  gpr_mu_unlock(&q->mu);
+  return n;
+}
diff --git a/src/core/lib/gpr/mpscq.h b/src/core/lib/gpr/mpscq.h
new file mode 100644
index 0000000000..4409c5c9f5
--- /dev/null
+++ b/src/core/lib/gpr/mpscq.h
@@ -0,0 +1,84 @@
+/*
+ *
+ * Copyright 2016 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_GPR_MPSCQ_H
+#define GRPC_CORE_LIB_GPR_MPSCQ_H
+
+#include <grpc/support/atm.h>
+#include <grpc/support/sync.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+// Multiple-producer single-consumer lock free queue, based upon the
+// implementation from Dmitry Vyukov here:
+// http://www.1024cores.net/home/lock-free-algorithms/queues/intrusive-mpsc-node-based-queue
+
+// List node (include this in a data structure at the top, and add application
+// fields after it - to simulate inheritance)
+typedef struct gpr_mpscq_node {
+  gpr_atm next;
+} gpr_mpscq_node;
+
+// Actual queue type
+typedef struct gpr_mpscq {
+  gpr_atm head;
+  // make sure head & tail don't share a cacheline
+  char padding[GPR_CACHELINE_SIZE];
+  gpr_mpscq_node* tail;
+  gpr_mpscq_node stub;
+} gpr_mpscq;
+
+void gpr_mpscq_init(gpr_mpscq* q);
+void gpr_mpscq_destroy(gpr_mpscq* q);
+// Push a node
+// Thread safe - can be called from multiple threads concurrently
+// Returns true if this was possibly the first node (may return true
+// sporadically, will not return false sporadically)
+bool gpr_mpscq_push(gpr_mpscq* q, gpr_mpscq_node* n);
+// Pop a node (returns NULL if no node is ready - which doesn't indicate that
+// the queue is empty!!)
+// Thread compatible - can only be called from one thread at a time
+gpr_mpscq_node* gpr_mpscq_pop(gpr_mpscq* q);
+// Pop a node; sets *empty to true if the queue is empty, or false if it is not
+gpr_mpscq_node* gpr_mpscq_pop_and_check_end(gpr_mpscq* q, bool* empty);
+
+// An mpscq with a lock: it's safe to pop from multiple threads, but doing
+// only one thread will succeed concurrently
+typedef struct gpr_locked_mpscq {
+  gpr_mpscq queue;
+  gpr_mu mu;
+} gpr_locked_mpscq;
+
+void gpr_locked_mpscq_init(gpr_locked_mpscq* q);
+void gpr_locked_mpscq_destroy(gpr_locked_mpscq* q);
+// Push a node
+// Thread safe - can be called from multiple threads concurrently
+// Returns true if this was possibly the first node (may return true
+// sporadically, will not return false sporadically)
+bool gpr_locked_mpscq_push(gpr_locked_mpscq* q, gpr_mpscq_node* n);
+
+// Pop a node (returns NULL if no node is ready - which doesn't indicate that
+// the queue is empty!!)
+// Thread safe - can be called from multiple threads concurrently
+gpr_mpscq_node* gpr_locked_mpscq_try_pop(gpr_locked_mpscq* q);
+
+// Pop a node.  Returns NULL only if the queue was empty at some point after
+// calling this function
+gpr_mpscq_node* gpr_locked_mpscq_pop(gpr_locked_mpscq* q);
+
+#endif /* GRPC_CORE_LIB_GPR_MPSCQ_H */
diff --git a/src/core/lib/gpr/murmur_hash.cc b/src/core/lib/gpr/murmur_hash.cc
new file mode 100644
index 0000000000..3f5e04d211
--- /dev/null
+++ b/src/core/lib/gpr/murmur_hash.cc
@@ -0,0 +1,78 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include "src/core/lib/gpr/murmur_hash.h"
+
+#include <string.h>
+
+#define ROTL32(x, r) ((x) << (r)) | ((x) >> (32 - (r)))
+
+#define FMIX32(h)    \
+  (h) ^= (h) >> 16;  \
+  (h) *= 0x85ebca6b; \
+  (h) ^= (h) >> 13;  \
+  (h) *= 0xc2b2ae35; \
+  (h) ^= (h) >> 16;
+
+uint32_t gpr_murmur_hash3(const void* key, size_t len, uint32_t seed) {
+  uint32_t h1 = seed;
+  uint32_t k1;
+
+  const uint32_t c1 = 0xcc9e2d51;
+  const uint32_t c2 = 0x1b873593;
+
+  const uint8_t* keyptr = (const uint8_t*)key;
+  const size_t bsize = sizeof(k1);
+  const size_t nblocks = len / bsize;
+
+  /* body */
+  for (size_t i = 0; i < nblocks; i++, keyptr += bsize) {
+    memcpy(&k1, keyptr, bsize);
+
+    k1 *= c1;
+    k1 = ROTL32(k1, 15);
+    k1 *= c2;
+
+    h1 ^= k1;
+    h1 = ROTL32(h1, 13);
+    h1 = h1 * 5 + 0xe6546b64;
+  }
+
+  k1 = 0;
+
+  /* tail */
+  switch (len & 3) {
+    case 3:
+      k1 ^= ((uint32_t)keyptr[2]) << 16;
+    /* fallthrough */
+    case 2:
+      k1 ^= ((uint32_t)keyptr[1]) << 8;
+    /* fallthrough */
+    case 1:
+      k1 ^= keyptr[0];
+      k1 *= c1;
+      k1 = ROTL32(k1, 15);
+      k1 *= c2;
+      h1 ^= k1;
+  };
+
+  /* finalization */
+  h1 ^= (uint32_t)len;
+  FMIX32(h1);
+  return h1;
+}
diff --git a/src/core/lib/gpr/murmur_hash.h b/src/core/lib/gpr/murmur_hash.h
new file mode 100644
index 0000000000..8004889a9a
--- /dev/null
+++ b/src/core/lib/gpr/murmur_hash.h
@@ -0,0 +1,29 @@
+/*
+ *
+ * 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_GPR_MURMUR_HASH_H
+#define GRPC_CORE_LIB_GPR_MURMUR_HASH_H
+
+#include <grpc/support/port_platform.h>
+
+#include <stddef.h>
+
+/* compute the hash of key (length len) */
+uint32_t gpr_murmur_hash3(const void* key, size_t len, uint32_t seed);
+
+#endif /* GRPC_CORE_LIB_GPR_MURMUR_HASH_H */
diff --git a/src/core/lib/gpr/spinlock.h b/src/core/lib/gpr/spinlock.h
new file mode 100644
index 0000000000..f03be1d791
--- /dev/null
+++ b/src/core/lib/gpr/spinlock.h
@@ -0,0 +1,44 @@
+/*
+ *
+ * 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_GPR_SPINLOCK_H
+#define GRPC_CORE_LIB_GPR_SPINLOCK_H
+
+#include <grpc/support/atm.h>
+
+/* Simple spinlock. No backoff strategy, gpr_spinlock_lock is almost always
+   a concurrency code smell. */
+typedef struct {
+  gpr_atm atm;
+} gpr_spinlock;
+
+#ifdef __cplusplus
+#define GPR_SPINLOCK_INITIALIZER (gpr_spinlock{0})
+#else
+#define GPR_SPINLOCK_INITIALIZER ((gpr_spinlock){0})
+#endif
+#define GPR_SPINLOCK_STATIC_INITIALIZER \
+  { 0 }
+
+#define gpr_spinlock_trylock(lock) (gpr_atm_acq_cas(&(lock)->atm, 0, 1))
+#define gpr_spinlock_unlock(lock) (gpr_atm_rel_store(&(lock)->atm, 0))
+#define gpr_spinlock_lock(lock) \
+  do {                          \
+  } while (!gpr_spinlock_trylock((lock)))
+
+#endif /* GRPC_CORE_LIB_GPR_SPINLOCK_H */
diff --git a/src/core/lib/gpr/string.cc b/src/core/lib/gpr/string.cc
new file mode 100644
index 0000000000..919d957d1b
--- /dev/null
+++ b/src/core/lib/gpr/string.cc
@@ -0,0 +1,315 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include "src/core/lib/gpr/string.h"
+
+#include <ctype.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
+
+char* gpr_strdup(const char* src) {
+  char* dst;
+  size_t len;
+
+  if (!src) {
+    return nullptr;
+  }
+
+  len = strlen(src) + 1;
+  dst = (char*)gpr_malloc(len);
+
+  memcpy(dst, src, len);
+
+  return dst;
+}
+
+typedef struct {
+  size_t capacity;
+  size_t length;
+  char* data;
+} dump_out;
+
+static dump_out dump_out_create(void) {
+  dump_out r = {0, 0, nullptr};
+  return r;
+}
+
+static void dump_out_append(dump_out* out, char c) {
+  if (out->length == out->capacity) {
+    out->capacity = GPR_MAX(8, 2 * out->capacity);
+    out->data = (char*)gpr_realloc(out->data, out->capacity);
+  }
+  out->data[out->length++] = c;
+}
+
+static void hexdump(dump_out* out, const char* buf, size_t len) {
+  static const char* hex = "0123456789abcdef";
+
+  const uint8_t* const beg = (const uint8_t*)buf;
+  const uint8_t* const end = beg + len;
+  const uint8_t* cur;
+
+  for (cur = beg; cur != end; ++cur) {
+    if (cur != beg) dump_out_append(out, ' ');
+    dump_out_append(out, hex[*cur >> 4]);
+    dump_out_append(out, hex[*cur & 0xf]);
+  }
+}
+
+static void asciidump(dump_out* out, const char* buf, size_t len) {
+  const uint8_t* const beg = (const uint8_t*)buf;
+  const uint8_t* const end = beg + len;
+  const uint8_t* cur;
+  int out_was_empty = (out->length == 0);
+  if (!out_was_empty) {
+    dump_out_append(out, ' ');
+    dump_out_append(out, '\'');
+  }
+  for (cur = beg; cur != end; ++cur) {
+    dump_out_append(out, (char)(isprint(*cur) ? *(char*)cur : '.'));
+  }
+  if (!out_was_empty) {
+    dump_out_append(out, '\'');
+  }
+}
+
+char* gpr_dump(const char* buf, size_t len, uint32_t flags) {
+  dump_out out = dump_out_create();
+  if (flags & GPR_DUMP_HEX) {
+    hexdump(&out, buf, len);
+  }
+  if (flags & GPR_DUMP_ASCII) {
+    asciidump(&out, buf, len);
+  }
+  dump_out_append(&out, 0);
+  return out.data;
+}
+
+int gpr_parse_bytes_to_uint32(const char* buf, size_t len, uint32_t* result) {
+  uint32_t out = 0;
+  uint32_t new_val;
+  size_t i;
+
+  if (len == 0) return 0; /* must have some bytes */
+
+  for (i = 0; i < len; i++) {
+    if (buf[i] < '0' || buf[i] > '9') return 0; /* bad char */
+    new_val = 10 * out + (uint32_t)(buf[i] - '0');
+    if (new_val < out) return 0; /* overflow */
+    out = new_val;
+  }
+
+  *result = out;
+  return 1;
+}
+
+void gpr_reverse_bytes(char* str, int len) {
+  char *p1, *p2;
+  for (p1 = str, p2 = str + len - 1; p2 > p1; ++p1, --p2) {
+    char temp = *p1;
+    *p1 = *p2;
+    *p2 = temp;
+  }
+}
+
+int gpr_ltoa(long value, char* string) {
+  long sign;
+  int i = 0;
+
+  if (value == 0) {
+    string[0] = '0';
+    string[1] = 0;
+    return 1;
+  }
+
+  sign = value < 0 ? -1 : 1;
+  while (value) {
+    string[i++] = (char)('0' + sign * (value % 10));
+    value /= 10;
+  }
+  if (sign < 0) string[i++] = '-';
+  gpr_reverse_bytes(string, i);
+  string[i] = 0;
+  return i;
+}
+
+int int64_ttoa(int64_t value, char* string) {
+  int64_t sign;
+  int i = 0;
+
+  if (value == 0) {
+    string[0] = '0';
+    string[1] = 0;
+    return 1;
+  }
+
+  sign = value < 0 ? -1 : 1;
+  while (value) {
+    string[i++] = (char)('0' + sign * (value % 10));
+    value /= 10;
+  }
+  if (sign < 0) string[i++] = '-';
+  gpr_reverse_bytes(string, i);
+  string[i] = 0;
+  return i;
+}
+
+int gpr_parse_nonnegative_int(const char* value) {
+  char* end;
+  long result = strtol(value, &end, 0);
+  if (*end != '\0' || result < 0 || result > INT_MAX) return -1;
+  return (int)result;
+}
+
+char* gpr_leftpad(const char* str, char flag, size_t length) {
+  const size_t str_length = strlen(str);
+  const size_t out_length = str_length > length ? str_length : length;
+  char* out = (char*)gpr_malloc(out_length + 1);
+  memset(out, flag, out_length - str_length);
+  memcpy(out + out_length - str_length, str, str_length);
+  out[out_length] = 0;
+  return out;
+}
+
+char* gpr_strjoin(const char** strs, size_t nstrs, size_t* final_length) {
+  return gpr_strjoin_sep(strs, nstrs, "", final_length);
+}
+
+char* gpr_strjoin_sep(const char** strs, size_t nstrs, const char* sep,
+                      size_t* final_length) {
+  const size_t sep_len = strlen(sep);
+  size_t out_length = 0;
+  size_t i;
+  char* out;
+  for (i = 0; i < nstrs; i++) {
+    out_length += strlen(strs[i]);
+  }
+  out_length += 1; /* null terminator */
+  if (nstrs > 0) {
+    out_length += sep_len * (nstrs - 1); /* separators */
+  }
+  out = (char*)gpr_malloc(out_length);
+  out_length = 0;
+  for (i = 0; i < nstrs; i++) {
+    const size_t slen = strlen(strs[i]);
+    if (i != 0) {
+      memcpy(out + out_length, sep, sep_len);
+      out_length += sep_len;
+    }
+    memcpy(out + out_length, strs[i], slen);
+    out_length += slen;
+  }
+  out[out_length] = 0;
+  if (final_length != nullptr) {
+    *final_length = out_length;
+  }
+  return out;
+}
+
+void gpr_strvec_init(gpr_strvec* sv) { memset(sv, 0, sizeof(*sv)); }
+
+void gpr_strvec_destroy(gpr_strvec* sv) {
+  size_t i;
+  for (i = 0; i < sv->count; i++) {
+    gpr_free(sv->strs[i]);
+  }
+  gpr_free(sv->strs);
+}
+
+void gpr_strvec_add(gpr_strvec* sv, char* str) {
+  if (sv->count == sv->capacity) {
+    sv->capacity = GPR_MAX(sv->capacity + 8, sv->capacity * 2);
+    sv->strs = (char**)gpr_realloc(sv->strs, sizeof(char*) * sv->capacity);
+  }
+  sv->strs[sv->count++] = str;
+}
+
+char* gpr_strvec_flatten(gpr_strvec* sv, size_t* final_length) {
+  return gpr_strjoin((const char**)sv->strs, sv->count, final_length);
+}
+
+int gpr_stricmp(const char* a, const char* b) {
+  int ca, cb;
+  do {
+    ca = tolower(*a);
+    cb = tolower(*b);
+    ++a;
+    ++b;
+  } while (ca == cb && ca && cb);
+  return ca - cb;
+}
+
+static void add_string_to_split(const char* beg, const char* end, char*** strs,
+                                size_t* nstrs, size_t* capstrs) {
+  char* out = (char*)gpr_malloc((size_t)(end - beg) + 1);
+  memcpy(out, beg, (size_t)(end - beg));
+  out[end - beg] = 0;
+  if (*nstrs == *capstrs) {
+    *capstrs = GPR_MAX(8, 2 * *capstrs);
+    *strs = (char**)gpr_realloc(*strs, sizeof(*strs) * *capstrs);
+  }
+  (*strs)[*nstrs] = out;
+  ++*nstrs;
+}
+
+void gpr_string_split(const char* input, const char* sep, char*** strs,
+                      size_t* nstrs) {
+  const char* next;
+  *strs = nullptr;
+  *nstrs = 0;
+  size_t capstrs = 0;
+  while ((next = strstr(input, sep))) {
+    add_string_to_split(input, next, strs, nstrs, &capstrs);
+    input = next + strlen(sep);
+  }
+  add_string_to_split(input, input + strlen(input), strs, nstrs, &capstrs);
+}
+
+void* gpr_memrchr(const void* s, int c, size_t n) {
+  if (s == nullptr) return nullptr;
+  char* b = (char*)s;
+  size_t i;
+  for (i = 0; i < n; i++) {
+    if (b[n - i - 1] == c) {
+      return &b[n - i - 1];
+    }
+  }
+  return nullptr;
+}
+
+bool gpr_is_true(const char* s) {
+  size_t i;
+  if (s == nullptr) {
+    return false;
+  }
+  static const char* truthy[] = {"yes", "true", "1"};
+  for (i = 0; i < GPR_ARRAY_SIZE(truthy); i++) {
+    if (0 == gpr_stricmp(s, truthy[i])) {
+      return true;
+    }
+  }
+  return false;
+}
diff --git a/src/core/lib/gpr/string.h b/src/core/lib/gpr/string.h
new file mode 100644
index 0000000000..ef3a8c6086
--- /dev/null
+++ b/src/core/lib/gpr/string.h
@@ -0,0 +1,109 @@
+/*
+ *
+ * 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_GPR_STRING_H
+#define GRPC_CORE_LIB_GPR_STRING_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#include <grpc/support/port_platform.h>
+
+/* String utility functions */
+
+/* Flags for gpr_dump function. */
+#define GPR_DUMP_HEX 0x00000001
+#define GPR_DUMP_ASCII 0x00000002
+
+/* Converts array buf, of length len, into a C string  according to the flags.
+   Result should be freed with gpr_free() */
+char* gpr_dump(const char* buf, size_t len, uint32_t flags);
+
+/* Parses an array of bytes into an integer (base 10). Returns 1 on success,
+   0 on failure. */
+int gpr_parse_bytes_to_uint32(const char* data, size_t length,
+                              uint32_t* result);
+
+/* Minimum buffer size for calling ltoa */
+#define GPR_LTOA_MIN_BUFSIZE (3 * sizeof(long))
+
+/* Convert a long to a string in base 10; returns the length of the
+   output string (or 0 on failure).
+   output must be at least GPR_LTOA_MIN_BUFSIZE bytes long. */
+int gpr_ltoa(long value, char* output);
+
+/* Minimum buffer size for calling int64toa */
+#define GPR_INT64TOA_MIN_BUFSIZE (3 * sizeof(int64_t))
+
+/* Convert an int64 to a string in base 10; returns the length of the
+output string (or 0 on failure).
+output must be at least GPR_INT64TOA_MIN_BUFSIZE bytes long.
+NOTE: This function ensures sufficient bit width even on Win x64,
+where long is 32bit is size.*/
+int int64_ttoa(int64_t value, char* output);
+
+// Parses a non-negative number from a value string.  Returns -1 on error.
+int gpr_parse_nonnegative_int(const char* value);
+
+/* Reverse a run of bytes */
+void gpr_reverse_bytes(char* str, int len);
+
+/* Pad a string with flag characters. The given length specifies the minimum
+   field width. The input string is never truncated. */
+char* gpr_leftpad(const char* str, char flag, size_t length);
+
+/* Join a set of strings, returning the resulting string.
+   Total combined length (excluding null terminator) is returned in total_length
+   if it is non-null. */
+char* gpr_strjoin(const char** strs, size_t nstrs, size_t* total_length);
+
+/* Join a set of strings using a separator, returning the resulting string.
+   Total combined length (excluding null terminator) is returned in total_length
+   if it is non-null. */
+char* gpr_strjoin_sep(const char** strs, size_t nstrs, const char* sep,
+                      size_t* total_length);
+
+void gpr_string_split(const char* input, const char* sep, char*** strs,
+                      size_t* nstrs);
+
+/* A vector of strings... for building up a final string one piece at a time */
+typedef struct {
+  char** strs;
+  size_t count;
+  size_t capacity;
+} gpr_strvec;
+
+/* Initialize/destroy */
+void gpr_strvec_init(gpr_strvec* strs);
+void gpr_strvec_destroy(gpr_strvec* strs);
+/* Add a string to a strvec, takes ownership of the string */
+void gpr_strvec_add(gpr_strvec* strs, char* add);
+/* Return a joined string with all added substrings, optionally setting
+   total_length as per gpr_strjoin */
+char* gpr_strvec_flatten(gpr_strvec* strs, size_t* total_length);
+
+/** Case insensitive string comparison... return <0 if lower(a)<lower(b), ==0 if
+    lower(a)==lower(b), >0 if lower(a)>lower(b) */
+int gpr_stricmp(const char* a, const char* b);
+
+void* gpr_memrchr(const void* s, int c, size_t n);
+
+/** Return true if lower(s) equals "true", "yes" or "1", otherwise false. */
+bool gpr_is_true(const char* s);
+
+#endif /* GRPC_CORE_LIB_GPR_STRING_H */
diff --git a/src/core/lib/gpr/string_posix.cc b/src/core/lib/gpr/string_posix.cc
new file mode 100644
index 0000000000..8b818e39b9
--- /dev/null
+++ b/src/core/lib/gpr/string_posix.cc
@@ -0,0 +1,72 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_STRING
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+int gpr_asprintf(char** strp, const char* format, ...) {
+  va_list args;
+  int ret;
+  char buf[64];
+  size_t strp_buflen;
+
+  /* Use a constant-sized buffer to determine the length. */
+  va_start(args, format);
+  ret = vsnprintf(buf, sizeof(buf), format, args);
+  va_end(args);
+  if (ret < 0) {
+    *strp = nullptr;
+    return -1;
+  }
+
+  /* Allocate a new buffer, with space for the NUL terminator. */
+  strp_buflen = (size_t)ret + 1;
+  if ((*strp = (char*)gpr_malloc(strp_buflen)) == nullptr) {
+    /* This shouldn't happen, because gpr_malloc() calls abort(). */
+    return -1;
+  }
+
+  /* Return early if we have all the bytes. */
+  if (strp_buflen <= sizeof(buf)) {
+    memcpy(*strp, buf, strp_buflen);
+    return ret;
+  }
+
+  /* Try again using the larger buffer. */
+  va_start(args, format);
+  ret = vsnprintf(*strp, strp_buflen, format, args);
+  va_end(args);
+  if ((size_t)ret == strp_buflen - 1) {
+    return ret;
+  }
+
+  /* This should never happen. */
+  gpr_free(*strp);
+  *strp = nullptr;
+  return -1;
+}
+
+#endif /* GPR_POSIX_STRING */
diff --git a/src/core/lib/gpr/string_util_windows.cc b/src/core/lib/gpr/string_util_windows.cc
new file mode 100644
index 0000000000..8c8c99cd21
--- /dev/null
+++ b/src/core/lib/gpr/string_util_windows.cc
@@ -0,0 +1,82 @@
+/*
+ *
+ * Copyright 2016 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.
+ *
+ */
+
+/* Posix code for gpr snprintf support. */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS
+
+/* Some platforms (namely msys) need wchar to be included BEFORE
+   anything else, especially strsafe.h. */
+#include <wchar.h>
+
+#include <inttypes.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <strsafe.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log_windows.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gpr/string_windows.h"
+
+#if defined UNICODE || defined _UNICODE
+LPTSTR
+gpr_char_to_tchar(LPCSTR input) {
+  LPTSTR ret;
+  int needed = MultiByteToWideChar(CP_UTF8, 0, input, -1, NULL, 0);
+  if (needed <= 0) return NULL;
+  ret = (LPTSTR)gpr_malloc((unsigned)needed * sizeof(TCHAR));
+  MultiByteToWideChar(CP_UTF8, 0, input, -1, ret, needed);
+  return ret;
+}
+
+LPSTR
+gpr_tchar_to_char(LPCTSTR input) {
+  LPSTR ret;
+  int needed = WideCharToMultiByte(CP_UTF8, 0, input, -1, NULL, 0, NULL, NULL);
+  if (needed <= 0) return NULL;
+  ret = (LPSTR)gpr_malloc((unsigned)needed);
+  WideCharToMultiByte(CP_UTF8, 0, input, -1, ret, needed, NULL, NULL);
+  return ret;
+}
+#else
+LPSTR gpr_tchar_to_char(LPCTSTR input) { return (LPSTR)gpr_strdup(input); }
+
+LPTSTR gpr_char_to_tchar(LPCTSTR input) { return (LPTSTR)gpr_strdup(input); }
+#endif
+
+char* gpr_format_message(int messageid) {
+  LPTSTR tmessage;
+  char* message;
+  DWORD status = FormatMessage(
+      FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+          FORMAT_MESSAGE_IGNORE_INSERTS,
+      NULL, (DWORD)messageid, MAKELANGID(LANG_ENGLISH, SUBLANG_DEFAULT),
+      (LPTSTR)(&tmessage), 0, NULL);
+  if (status == 0) return gpr_strdup("Unable to retrieve error string");
+  message = gpr_tchar_to_char(tmessage);
+  LocalFree(tmessage);
+  return message;
+}
+
+#endif /* GPR_WINDOWS */
diff --git a/src/core/lib/gpr/string_windows.cc b/src/core/lib/gpr/string_windows.cc
new file mode 100644
index 0000000000..25bfd412e4
--- /dev/null
+++ b/src/core/lib/gpr/string_windows.cc
@@ -0,0 +1,69 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* Windows code for gpr snprintf support. */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS_STRING
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/gpr/string.h"
+
+int gpr_asprintf(char** strp, const char* format, ...) {
+  va_list args;
+  int ret;
+  size_t strp_buflen;
+
+  /* Determine the length. */
+  va_start(args, format);
+  ret = _vscprintf(format, args);
+  va_end(args);
+  if (ret < 0) {
+    *strp = NULL;
+    return -1;
+  }
+
+  /* Allocate a new buffer, with space for the NUL terminator. */
+  strp_buflen = (size_t)ret + 1;
+  if ((*strp = (char*)gpr_malloc(strp_buflen)) == NULL) {
+    /* This shouldn't happen, because gpr_malloc() calls abort(). */
+    return -1;
+  }
+
+  /* Print to the buffer. */
+  va_start(args, format);
+  ret = vsnprintf_s(*strp, strp_buflen, _TRUNCATE, format, args);
+  va_end(args);
+  if ((size_t)ret == strp_buflen - 1) {
+    return ret;
+  }
+
+  /* This should never happen. */
+  gpr_free(*strp);
+  *strp = NULL;
+  return -1;
+}
+
+#endif /* GPR_WINDOWS_STRING */
diff --git a/src/core/lib/gpr/string_windows.h b/src/core/lib/gpr/string_windows.h
new file mode 100644
index 0000000000..e370f802cf
--- /dev/null
+++ b/src/core/lib/gpr/string_windows.h
@@ -0,0 +1,32 @@
+/*
+ *
+ * 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_GPR_STRING_WINDOWS_H
+#define GRPC_CORE_LIB_GPR_STRING_WINDOWS_H
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS
+
+/* These allocate new strings using gpr_malloc to convert from and to utf-8. */
+LPTSTR gpr_char_to_tchar(LPCSTR input);
+LPSTR gpr_tchar_to_char(LPCTSTR input);
+
+#endif /* GPR_WINDOWS */
+
+#endif /* GRPC_CORE_LIB_GPR_STRING_WINDOWS_H */
diff --git a/src/core/lib/gpr/subprocess_posix.cc b/src/core/lib/gpr/subprocess_posix.cc
new file mode 100644
index 0000000000..dc046b6499
--- /dev/null
+++ b/src/core/lib/gpr/subprocess_posix.cc
@@ -0,0 +1,99 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_SUBPROCESS
+
+#include <grpc/support/subprocess.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+struct gpr_subprocess {
+  int pid;
+  bool joined;
+};
+
+const char* gpr_subprocess_binary_extension() { return ""; }
+
+gpr_subprocess* gpr_subprocess_create(int argc, const char** argv) {
+  gpr_subprocess* r;
+  int pid;
+  char** exec_args;
+
+  pid = fork();
+  if (pid == -1) {
+    return nullptr;
+  } else if (pid == 0) {
+    exec_args = (char**)gpr_malloc(((size_t)argc + 1) * sizeof(char*));
+    memcpy(exec_args, argv, (size_t)argc * sizeof(char*));
+    exec_args[argc] = nullptr;
+    execv(exec_args[0], exec_args);
+    /* if we reach here, an error has occurred */
+    gpr_log(GPR_ERROR, "execv '%s' failed: %s", exec_args[0], strerror(errno));
+    _exit(1);
+    return nullptr;
+  } else {
+    r = (gpr_subprocess*)gpr_zalloc(sizeof(gpr_subprocess));
+    r->pid = pid;
+    return r;
+  }
+}
+
+void gpr_subprocess_destroy(gpr_subprocess* p) {
+  if (!p->joined) {
+    kill(p->pid, SIGKILL);
+    gpr_subprocess_join(p);
+  }
+  gpr_free(p);
+}
+
+int gpr_subprocess_join(gpr_subprocess* p) {
+  int status;
+retry:
+  if (waitpid(p->pid, &status, 0) == -1) {
+    if (errno == EINTR) {
+      goto retry;
+    }
+    gpr_log(GPR_ERROR, "waitpid failed for pid %d: %s", p->pid,
+            strerror(errno));
+    return -1;
+  }
+  p->joined = true;
+  return status;
+}
+
+void gpr_subprocess_interrupt(gpr_subprocess* p) {
+  if (!p->joined) {
+    kill(p->pid, SIGINT);
+  }
+}
+
+#endif /* GPR_POSIX_SUBPROCESS */
diff --git a/src/core/lib/gpr/subprocess_windows.cc b/src/core/lib/gpr/subprocess_windows.cc
new file mode 100644
index 0000000000..1947d475e3
--- /dev/null
+++ b/src/core/lib/gpr/subprocess_windows.cc
@@ -0,0 +1,126 @@
+/*
+ *
+ * Copyright 2016 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 <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS_SUBPROCESS
+
+#include <string.h>
+#include <tchar.h>
+#include <windows.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/subprocess.h>
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gpr/string_windows.h"
+
+struct gpr_subprocess {
+  PROCESS_INFORMATION pi;
+  int joined;
+  int interrupted;
+};
+
+const char* gpr_subprocess_binary_extension() { return ".exe"; }
+
+gpr_subprocess* gpr_subprocess_create(int argc, const char** argv) {
+  gpr_subprocess* r;
+
+  STARTUPINFO si;
+  PROCESS_INFORMATION pi;
+
+  char* args = gpr_strjoin_sep(argv, (size_t)argc, " ", NULL);
+  TCHAR* args_tchar;
+
+  args_tchar = gpr_char_to_tchar(args);
+  gpr_free(args);
+
+  memset(&si, 0, sizeof(si));
+  si.cb = sizeof(si);
+  memset(&pi, 0, sizeof(pi));
+
+  if (!CreateProcess(NULL, args_tchar, NULL, NULL, FALSE,
+                     CREATE_NEW_PROCESS_GROUP, NULL, NULL, &si, &pi)) {
+    gpr_free(args_tchar);
+    return NULL;
+  }
+  gpr_free(args_tchar);
+
+  r = (gpr_subprocess*)gpr_malloc(sizeof(gpr_subprocess));
+  memset(r, 0, sizeof(*r));
+  r->pi = pi;
+  return r;
+}
+
+void gpr_subprocess_destroy(gpr_subprocess* p) {
+  if (p) {
+    if (!p->joined) {
+      gpr_subprocess_interrupt(p);
+      gpr_subprocess_join(p);
+    }
+    if (p->pi.hProcess) {
+      CloseHandle(p->pi.hProcess);
+    }
+    if (p->pi.hThread) {
+      CloseHandle(p->pi.hThread);
+    }
+    gpr_free(p);
+  }
+}
+
+int gpr_subprocess_join(gpr_subprocess* p) {
+  DWORD dwExitCode;
+  if (GetExitCodeProcess(p->pi.hProcess, &dwExitCode)) {
+    if (dwExitCode == STILL_ACTIVE) {
+      if (WaitForSingleObject(p->pi.hProcess, INFINITE) == WAIT_OBJECT_0) {
+        p->joined = 1;
+        goto getExitCode;
+      }
+      return -1;  // failed to join
+    } else {
+      goto getExitCode;
+    }
+  } else {
+    return -1;  // failed to get exit code
+  }
+
+getExitCode:
+  if (p->interrupted) {
+    return 0;
+  }
+  if (GetExitCodeProcess(p->pi.hProcess, &dwExitCode)) {
+    return (int)dwExitCode;
+  } else {
+    return -1;  // failed to get exit code
+  }
+}
+
+void gpr_subprocess_interrupt(gpr_subprocess* p) {
+  DWORD dwExitCode;
+  if (GetExitCodeProcess(p->pi.hProcess, &dwExitCode)) {
+    if (dwExitCode == STILL_ACTIVE) {
+      gpr_log(GPR_INFO, "sending ctrl-break");
+      GenerateConsoleCtrlEvent(CTRL_BREAK_EVENT, p->pi.dwProcessId);
+      p->joined = 1;
+      p->interrupted = 1;
+    }
+  }
+  return;
+}
+
+#endif /* GPR_WINDOWS_SUBPROCESS */
diff --git a/src/core/lib/gpr/sync.cc b/src/core/lib/gpr/sync.cc
new file mode 100644
index 0000000000..347ffcd00e
--- /dev/null
+++ b/src/core/lib/gpr/sync.cc
@@ -0,0 +1,122 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* Generic implementation of synchronization primitives. */
+
+#include <grpc/support/atm.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+
+#include <assert.h>
+
+/* Number of mutexes to allocate for events, to avoid lock contention.
+   Should be a prime. */
+enum { event_sync_partitions = 31 };
+
+/* Events are partitioned by address to avoid lock contention. */
+static struct sync_array_s {
+  gpr_mu mu;
+  gpr_cv cv;
+} sync_array[event_sync_partitions];
+
+/* This routine is executed once on first use, via event_once */
+static gpr_once event_once = GPR_ONCE_INIT;
+static void event_initialize(void) {
+  int i;
+  for (i = 0; i != event_sync_partitions; i++) {
+    gpr_mu_init(&sync_array[i].mu);
+    gpr_cv_init(&sync_array[i].cv);
+  }
+}
+
+/* Hash ev into an element of sync_array[]. */
+static struct sync_array_s* hash(gpr_event* ev) {
+  return &sync_array[((uintptr_t)ev) % event_sync_partitions];
+}
+
+void gpr_event_init(gpr_event* ev) {
+  gpr_once_init(&event_once, &event_initialize);
+  ev->state = 0;
+}
+
+void gpr_event_set(gpr_event* ev, void* value) {
+  struct sync_array_s* s = hash(ev);
+  gpr_mu_lock(&s->mu);
+  GPR_ASSERT(gpr_atm_acq_load(&ev->state) == 0);
+  gpr_atm_rel_store(&ev->state, (gpr_atm)value);
+  gpr_cv_broadcast(&s->cv);
+  gpr_mu_unlock(&s->mu);
+  GPR_ASSERT(value != nullptr);
+}
+
+void* gpr_event_get(gpr_event* ev) {
+  return (void*)gpr_atm_acq_load(&ev->state);
+}
+
+void* gpr_event_wait(gpr_event* ev, gpr_timespec abs_deadline) {
+  void* result = (void*)gpr_atm_acq_load(&ev->state);
+  if (result == nullptr) {
+    struct sync_array_s* s = hash(ev);
+    gpr_mu_lock(&s->mu);
+    do {
+      result = (void*)gpr_atm_acq_load(&ev->state);
+    } while (result == nullptr && !gpr_cv_wait(&s->cv, &s->mu, abs_deadline));
+    gpr_mu_unlock(&s->mu);
+  }
+  return result;
+}
+
+void gpr_ref_init(gpr_refcount* r, int n) { gpr_atm_rel_store(&r->count, n); }
+
+void gpr_ref(gpr_refcount* r) { gpr_atm_no_barrier_fetch_add(&r->count, 1); }
+
+void gpr_ref_non_zero(gpr_refcount* r) {
+#ifndef NDEBUG
+  gpr_atm prior = gpr_atm_no_barrier_fetch_add(&r->count, 1);
+  assert(prior > 0);
+#else
+  gpr_ref(r);
+#endif
+}
+
+void gpr_refn(gpr_refcount* r, int n) {
+  gpr_atm_no_barrier_fetch_add(&r->count, n);
+}
+
+int gpr_unref(gpr_refcount* r) {
+  gpr_atm prior = gpr_atm_full_fetch_add(&r->count, -1);
+  GPR_ASSERT(prior > 0);
+  return prior == 1;
+}
+
+int gpr_ref_is_unique(gpr_refcount* r) {
+  return gpr_atm_acq_load(&r->count) == 1;
+}
+
+void gpr_stats_init(gpr_stats_counter* c, intptr_t n) {
+  gpr_atm_rel_store(&c->value, n);
+}
+
+void gpr_stats_inc(gpr_stats_counter* c, intptr_t inc) {
+  gpr_atm_no_barrier_fetch_add(&c->value, inc);
+}
+
+intptr_t gpr_stats_read(const gpr_stats_counter* c) {
+  /* don't need acquire-load, but we have no no-barrier load yet */
+  return gpr_atm_acq_load(&c->value);
+}
diff --git a/src/core/lib/gpr/sync_posix.cc b/src/core/lib/gpr/sync_posix.cc
new file mode 100644
index 0000000000..c3f6b10463
--- /dev/null
+++ b/src/core/lib/gpr/sync_posix.cc
@@ -0,0 +1,111 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_SYNC
+
+#include <errno.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/time.h>
+#include <time.h>
+#include "src/core/lib/profiling/timers.h"
+
+#ifdef GPR_LOW_LEVEL_COUNTERS
+gpr_atm gpr_mu_locks = 0;
+gpr_atm gpr_counter_atm_cas = 0;
+gpr_atm gpr_counter_atm_add = 0;
+#endif
+
+void gpr_mu_init(gpr_mu* mu) {
+  GPR_ASSERT(pthread_mutex_init(mu, nullptr) == 0);
+}
+
+void gpr_mu_destroy(gpr_mu* mu) { GPR_ASSERT(pthread_mutex_destroy(mu) == 0); }
+
+void gpr_mu_lock(gpr_mu* mu) {
+#ifdef GPR_LOW_LEVEL_COUNTERS
+  GPR_ATM_INC_COUNTER(gpr_mu_locks);
+#endif
+  GPR_TIMER_BEGIN("gpr_mu_lock", 0);
+  GPR_ASSERT(pthread_mutex_lock(mu) == 0);
+  GPR_TIMER_END("gpr_mu_lock", 0);
+}
+
+void gpr_mu_unlock(gpr_mu* mu) {
+  GPR_TIMER_BEGIN("gpr_mu_unlock", 0);
+  GPR_ASSERT(pthread_mutex_unlock(mu) == 0);
+  GPR_TIMER_END("gpr_mu_unlock", 0);
+}
+
+int gpr_mu_trylock(gpr_mu* mu) {
+  int err;
+  GPR_TIMER_BEGIN("gpr_mu_trylock", 0);
+  err = pthread_mutex_trylock(mu);
+  GPR_ASSERT(err == 0 || err == EBUSY);
+  GPR_TIMER_END("gpr_mu_trylock", 0);
+  return err == 0;
+}
+
+/*----------------------------------------*/
+
+void gpr_cv_init(gpr_cv* cv) {
+  pthread_condattr_t attr;
+  GPR_ASSERT(pthread_condattr_init(&attr) == 0);
+#if GPR_LINUX
+  GPR_ASSERT(pthread_condattr_setclock(&attr, CLOCK_MONOTONIC) == 0);
+#endif  // GPR_LINUX
+  GPR_ASSERT(pthread_cond_init(cv, &attr) == 0);
+}
+
+void gpr_cv_destroy(gpr_cv* cv) { GPR_ASSERT(pthread_cond_destroy(cv) == 0); }
+
+int gpr_cv_wait(gpr_cv* cv, gpr_mu* mu, gpr_timespec abs_deadline) {
+  int err = 0;
+  if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) ==
+      0) {
+    err = pthread_cond_wait(cv, mu);
+  } else {
+    struct timespec abs_deadline_ts;
+#if GPR_LINUX
+    abs_deadline = gpr_convert_clock_type(abs_deadline, GPR_CLOCK_MONOTONIC);
+#else
+    abs_deadline = gpr_convert_clock_type(abs_deadline, GPR_CLOCK_REALTIME);
+#endif  // GPR_LINUX
+    abs_deadline_ts.tv_sec = (time_t)abs_deadline.tv_sec;
+    abs_deadline_ts.tv_nsec = abs_deadline.tv_nsec;
+    err = pthread_cond_timedwait(cv, mu, &abs_deadline_ts);
+  }
+  GPR_ASSERT(err == 0 || err == ETIMEDOUT || err == EAGAIN);
+  return err == ETIMEDOUT;
+}
+
+void gpr_cv_signal(gpr_cv* cv) { GPR_ASSERT(pthread_cond_signal(cv) == 0); }
+
+void gpr_cv_broadcast(gpr_cv* cv) {
+  GPR_ASSERT(pthread_cond_broadcast(cv) == 0);
+}
+
+/*----------------------------------------*/
+
+void gpr_once_init(gpr_once* once, void (*init_function)(void)) {
+  GPR_ASSERT(pthread_once(once, init_function) == 0);
+}
+
+#endif /* GRP_POSIX_SYNC */
diff --git a/src/core/lib/gpr/sync_windows.cc b/src/core/lib/gpr/sync_windows.cc
new file mode 100644
index 0000000000..7cd41633d5
--- /dev/null
+++ b/src/core/lib/gpr/sync_windows.cc
@@ -0,0 +1,118 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* Win32 code for gpr synchronization support. */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS
+
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/time.h>
+
+void gpr_mu_init(gpr_mu* mu) {
+  InitializeCriticalSection(&mu->cs);
+  mu->locked = 0;
+}
+
+void gpr_mu_destroy(gpr_mu* mu) { DeleteCriticalSection(&mu->cs); }
+
+void gpr_mu_lock(gpr_mu* mu) {
+  EnterCriticalSection(&mu->cs);
+  GPR_ASSERT(!mu->locked);
+  mu->locked = 1;
+}
+
+void gpr_mu_unlock(gpr_mu* mu) {
+  mu->locked = 0;
+  LeaveCriticalSection(&mu->cs);
+}
+
+int gpr_mu_trylock(gpr_mu* mu) {
+  int result = TryEnterCriticalSection(&mu->cs);
+  if (result) {
+    if (mu->locked) {                /* This thread already holds the lock. */
+      LeaveCriticalSection(&mu->cs); /* Decrement lock count. */
+      result = 0;                    /* Indicate failure */
+    }
+    mu->locked = 1;
+  }
+  return result;
+}
+
+/*----------------------------------------*/
+
+void gpr_cv_init(gpr_cv* cv) { InitializeConditionVariable(cv); }
+
+void gpr_cv_destroy(gpr_cv* cv) {
+  /* Condition variables don't need destruction in Win32. */
+}
+
+int gpr_cv_wait(gpr_cv* cv, gpr_mu* mu, gpr_timespec abs_deadline) {
+  int timeout = 0;
+  DWORD timeout_max_ms;
+  mu->locked = 0;
+  if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) ==
+      0) {
+    SleepConditionVariableCS(cv, &mu->cs, INFINITE);
+  } else {
+    abs_deadline = gpr_convert_clock_type(abs_deadline, GPR_CLOCK_REALTIME);
+    gpr_timespec now = gpr_now(abs_deadline.clock_type);
+    int64_t now_ms = (int64_t)now.tv_sec * 1000 + now.tv_nsec / 1000000;
+    int64_t deadline_ms =
+        (int64_t)abs_deadline.tv_sec * 1000 + abs_deadline.tv_nsec / 1000000;
+    if (now_ms >= deadline_ms) {
+      timeout = 1;
+    } else {
+      if ((deadline_ms - now_ms) >= INFINITE) {
+        timeout_max_ms = INFINITE - 1;
+      } else {
+        timeout_max_ms = (DWORD)(deadline_ms - now_ms);
+      }
+      timeout = (SleepConditionVariableCS(cv, &mu->cs, timeout_max_ms) == 0 &&
+                 GetLastError() == ERROR_TIMEOUT);
+    }
+  }
+  mu->locked = 1;
+  return timeout;
+}
+
+void gpr_cv_signal(gpr_cv* cv) { WakeConditionVariable(cv); }
+
+void gpr_cv_broadcast(gpr_cv* cv) { WakeAllConditionVariable(cv); }
+
+/*----------------------------------------*/
+
+static void* dummy;
+struct run_once_func_arg {
+  void (*init_function)(void);
+};
+static BOOL CALLBACK run_once_func(gpr_once* once, void* v, void** pv) {
+  struct run_once_func_arg* arg = (struct run_once_func_arg*)v;
+  (*arg->init_function)();
+  return 1;
+}
+
+void gpr_once_init(gpr_once* once, void (*init_function)(void)) {
+  struct run_once_func_arg arg;
+  arg.init_function = init_function;
+  InitOnceExecuteOnce(once, run_once_func, &arg, &dummy);
+}
+
+#endif /* GPR_WINDOWS */
diff --git a/src/core/lib/gpr/thd.cc b/src/core/lib/gpr/thd.cc
new file mode 100644
index 0000000000..ca62615d65
--- /dev/null
+++ b/src/core/lib/gpr/thd.cc
@@ -0,0 +1,49 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* Posix implementation for gpr threads. */
+
+#include <string.h>
+
+#include <grpc/support/thd.h>
+
+enum { GPR_THD_JOINABLE = 1 };
+
+gpr_thd_options gpr_thd_options_default(void) {
+  gpr_thd_options options;
+  memset(&options, 0, sizeof(options));
+  return options;
+}
+
+void gpr_thd_options_set_detached(gpr_thd_options* options) {
+  options->flags &= ~GPR_THD_JOINABLE;
+}
+
+void gpr_thd_options_set_joinable(gpr_thd_options* options) {
+  options->flags |= GPR_THD_JOINABLE;
+}
+
+int gpr_thd_options_is_detached(const gpr_thd_options* options) {
+  if (!options) return 1;
+  return (options->flags & GPR_THD_JOINABLE) == 0;
+}
+
+int gpr_thd_options_is_joinable(const gpr_thd_options* options) {
+  if (!options) return 0;
+  return (options->flags & GPR_THD_JOINABLE) == GPR_THD_JOINABLE;
+}
diff --git a/src/core/lib/gpr/thd_internal.h b/src/core/lib/gpr/thd_internal.h
new file mode 100644
index 0000000000..692c00c8e1
--- /dev/null
+++ b/src/core/lib/gpr/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_GPR_THD_INTERNAL_H
+#define GRPC_CORE_LIB_GPR_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_GPR_THD_INTERNAL_H */
diff --git a/src/core/lib/gpr/thd_posix.cc b/src/core/lib/gpr/thd_posix.cc
new file mode 100644
index 0000000000..cfff0df6de
--- /dev/null
+++ b/src/core/lib/gpr/thd_posix.cc
@@ -0,0 +1,152 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* Posix implementation for gpr threads. */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_SYNC
+
+#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/gpr/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 */
+  const char* name;        /* name of thread. Can be nullptr. */
+};
+
+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);
+  if (a.name != nullptr) {
+#if GPR_APPLE_PTHREAD_NAME
+    /* Apple supports 64 characters, and will truncate if it's longer. */
+    pthread_setname_np(a.name);
+#elif GPR_LINUX_PTHREAD_NAME
+    /* Linux supports 16 characters max, and will error if it's longer. */
+    char buf[16];
+    size_t buf_len = GPR_ARRAY_SIZE(buf) - 1;
+    strncpy(buf, a.name, buf_len);
+    buf[buf_len] = '\0';
+    pthread_setname_np(pthread_self(), buf);
+#endif  // GPR_APPLE_PTHREAD_NAME
+  }
+  (*a.body)(a.arg);
+  dec_thd_count();
+  return nullptr;
+}
+
+int gpr_thd_new(gpr_thd_id* t, const char* thd_name,
+                void (*thd_body)(void* arg), void* arg,
+                const gpr_thd_options* options) {
+  int thread_started;
+  pthread_attr_t attr;
+  pthread_t p;
+  /* don't use gpr_malloc as we may cause an infinite recursion with
+   * the profiling code */
+  struct thd_arg* a = (struct thd_arg*)malloc(sizeof(*a));
+  GPR_ASSERT(a != nullptr);
+  a->body = thd_body;
+  a->arg = arg;
+  a->name = thd_name;
+  inc_thd_count();
+
+  GPR_ASSERT(pthread_attr_init(&attr) == 0);
+  if (gpr_thd_options_is_detached(options)) {
+    GPR_ASSERT(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) ==
+               0);
+  } else {
+    GPR_ASSERT(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE) ==
+               0);
+  }
+  thread_started = (pthread_create(&p, &attr, &thread_body, a) == 0);
+  GPR_ASSERT(pthread_attr_destroy(&attr) == 0);
+  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;
+}
+
+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/gpr/thd_windows.cc b/src/core/lib/gpr/thd_windows.cc
new file mode 100644
index 0000000000..f920770f32
--- /dev/null
+++ b/src/core/lib/gpr/thd_windows.cc
@@ -0,0 +1,105 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* Windows implementation for gpr threads. */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/thd.h>
+#include <string.h>
+
+#if defined(_MSC_VER)
+#define thread_local __declspec(thread)
+#elif defined(__GNUC__)
+#define thread_local __thread
+#else
+#error "Unknown compiler - please file a bug report"
+#endif
+
+struct thd_info {
+  void (*body)(void* arg); /* body of a thread */
+  void* arg;               /* argument to a thread */
+  HANDLE join_event;       /* if joinable, the join event */
+  int joinable;            /* true if not detached */
+};
+
+static thread_local struct thd_info* g_thd_info;
+
+/* Destroys a thread info */
+static void destroy_thread(struct thd_info* t) {
+  if (t->joinable) CloseHandle(t->join_event);
+  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;
+  g_thd_info->body(g_thd_info->arg);
+  if (g_thd_info->joinable) {
+    BOOL ret = SetEvent(g_thd_info->join_event);
+    GPR_ASSERT(ret);
+  } else {
+    destroy_thread(g_thd_info);
+  }
+  return 0;
+}
+
+int gpr_thd_new(gpr_thd_id* t, const char* thd_name,
+                void (*thd_body)(void* arg), void* arg,
+                const gpr_thd_options* options) {
+  HANDLE handle;
+  struct thd_info* info = (struct thd_info*)gpr_malloc(sizeof(*info));
+  info->body = thd_body;
+  info->arg = arg;
+  *t = 0;
+  if (gpr_thd_options_is_joinable(options)) {
+    info->joinable = 1;
+    info->join_event = CreateEvent(NULL, FALSE, FALSE, NULL);
+    if (info->join_event == NULL) {
+      gpr_free(info);
+      return 0;
+    }
+  } else {
+    info->joinable = 0;
+  }
+  handle = CreateThread(NULL, 64 * 1024, thread_body, info, 0, NULL);
+  if (handle == NULL) {
+    destroy_thread(info);
+  } else {
+    *t = (gpr_thd_id)info;
+    CloseHandle(handle);
+  }
+  return handle != NULL;
+}
+
+gpr_thd_id gpr_thd_currentid(void) { return (gpr_thd_id)g_thd_info; }
+
+void gpr_thd_join(gpr_thd_id t) {
+  struct thd_info* info = (struct thd_info*)t;
+  DWORD ret = WaitForSingleObject(info->join_event, INFINITE);
+  GPR_ASSERT(ret == WAIT_OBJECT_0);
+  destroy_thread(info);
+}
+
+#endif /* GPR_WINDOWS */
diff --git a/src/core/lib/gpr/time.cc b/src/core/lib/gpr/time.cc
new file mode 100644
index 0000000000..6903674d75
--- /dev/null
+++ b/src/core/lib/gpr/time.cc
@@ -0,0 +1,247 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* Generic implementation of time calls. */
+
+#include <grpc/support/log.h>
+#include <grpc/support/time.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+int gpr_time_cmp(gpr_timespec a, gpr_timespec b) {
+  int cmp = (a.tv_sec > b.tv_sec) - (a.tv_sec < b.tv_sec);
+  GPR_ASSERT(a.clock_type == b.clock_type);
+  if (cmp == 0 && a.tv_sec != INT64_MAX && a.tv_sec != INT64_MIN) {
+    cmp = (a.tv_nsec > b.tv_nsec) - (a.tv_nsec < b.tv_nsec);
+  }
+  return cmp;
+}
+
+gpr_timespec gpr_time_min(gpr_timespec a, gpr_timespec b) {
+  return gpr_time_cmp(a, b) < 0 ? a : b;
+}
+
+gpr_timespec gpr_time_max(gpr_timespec a, gpr_timespec b) {
+  return gpr_time_cmp(a, b) > 0 ? a : b;
+}
+
+gpr_timespec gpr_time_0(gpr_clock_type type) {
+  gpr_timespec out;
+  out.tv_sec = 0;
+  out.tv_nsec = 0;
+  out.clock_type = type;
+  return out;
+}
+
+gpr_timespec gpr_inf_future(gpr_clock_type type) {
+  gpr_timespec out;
+  out.tv_sec = INT64_MAX;
+  out.tv_nsec = 0;
+  out.clock_type = type;
+  return out;
+}
+
+gpr_timespec gpr_inf_past(gpr_clock_type type) {
+  gpr_timespec out;
+  out.tv_sec = INT64_MIN;
+  out.tv_nsec = 0;
+  out.clock_type = type;
+  return out;
+}
+
+static gpr_timespec to_seconds_from_sub_second_time(int64_t time_in_units,
+                                                    int64_t units_per_sec,
+                                                    gpr_clock_type type) {
+  gpr_timespec out;
+  if (time_in_units == INT64_MAX) {
+    out = gpr_inf_future(type);
+  } else if (time_in_units == INT64_MIN) {
+    out = gpr_inf_past(type);
+  } else {
+    if (time_in_units >= 0) {
+      out.tv_sec = time_in_units / units_per_sec;
+    } else {
+      out.tv_sec = (-((units_per_sec - 1) - (time_in_units + units_per_sec)) /
+                    units_per_sec) -
+                   1;
+    }
+    out.tv_nsec = (int32_t)((time_in_units - out.tv_sec * units_per_sec) *
+                            GPR_NS_PER_SEC / units_per_sec);
+    out.clock_type = type;
+  }
+  return out;
+}
+
+static gpr_timespec to_seconds_from_above_second_time(int64_t time_in_units,
+                                                      int64_t secs_per_unit,
+                                                      gpr_clock_type type) {
+  gpr_timespec out;
+  if (time_in_units >= INT64_MAX / secs_per_unit) {
+    out = gpr_inf_future(type);
+  } else if (time_in_units <= INT64_MIN / secs_per_unit) {
+    out = gpr_inf_past(type);
+  } else {
+    out.tv_sec = time_in_units * secs_per_unit;
+    out.tv_nsec = 0;
+    out.clock_type = type;
+  }
+  return out;
+}
+
+gpr_timespec gpr_time_from_nanos(int64_t ns, gpr_clock_type type) {
+  return to_seconds_from_sub_second_time(ns, GPR_NS_PER_SEC, type);
+}
+
+gpr_timespec gpr_time_from_micros(int64_t us, gpr_clock_type type) {
+  return to_seconds_from_sub_second_time(us, GPR_US_PER_SEC, type);
+}
+
+gpr_timespec gpr_time_from_millis(int64_t ms, gpr_clock_type type) {
+  return to_seconds_from_sub_second_time(ms, GPR_MS_PER_SEC, type);
+}
+
+gpr_timespec gpr_time_from_seconds(int64_t s, gpr_clock_type type) {
+  return to_seconds_from_sub_second_time(s, 1, type);
+}
+
+gpr_timespec gpr_time_from_minutes(int64_t m, gpr_clock_type type) {
+  return to_seconds_from_above_second_time(m, 60, type);
+}
+
+gpr_timespec gpr_time_from_hours(int64_t h, gpr_clock_type type) {
+  return to_seconds_from_above_second_time(h, 3600, type);
+}
+
+gpr_timespec gpr_time_add(gpr_timespec a, gpr_timespec b) {
+  gpr_timespec sum;
+  int64_t inc = 0;
+  GPR_ASSERT(b.clock_type == GPR_TIMESPAN);
+  sum.clock_type = a.clock_type;
+  sum.tv_nsec = a.tv_nsec + b.tv_nsec;
+  if (sum.tv_nsec >= GPR_NS_PER_SEC) {
+    sum.tv_nsec -= GPR_NS_PER_SEC;
+    inc++;
+  }
+  if (a.tv_sec == INT64_MAX || a.tv_sec == INT64_MIN) {
+    sum = a;
+  } else if (b.tv_sec == INT64_MAX ||
+             (b.tv_sec >= 0 && a.tv_sec >= INT64_MAX - b.tv_sec)) {
+    sum = gpr_inf_future(sum.clock_type);
+  } else if (b.tv_sec == INT64_MIN ||
+             (b.tv_sec <= 0 && a.tv_sec <= INT64_MIN - b.tv_sec)) {
+    sum = gpr_inf_past(sum.clock_type);
+  } else {
+    sum.tv_sec = a.tv_sec + b.tv_sec;
+    if (inc != 0 && sum.tv_sec == INT64_MAX - 1) {
+      sum = gpr_inf_future(sum.clock_type);
+    } else {
+      sum.tv_sec += inc;
+    }
+  }
+  return sum;
+}
+
+gpr_timespec gpr_time_sub(gpr_timespec a, gpr_timespec b) {
+  gpr_timespec diff;
+  int64_t dec = 0;
+  if (b.clock_type == GPR_TIMESPAN) {
+    diff.clock_type = a.clock_type;
+  } else {
+    GPR_ASSERT(a.clock_type == b.clock_type);
+    diff.clock_type = GPR_TIMESPAN;
+  }
+  diff.tv_nsec = a.tv_nsec - b.tv_nsec;
+  if (diff.tv_nsec < 0) {
+    diff.tv_nsec += GPR_NS_PER_SEC;
+    dec++;
+  }
+  if (a.tv_sec == INT64_MAX || a.tv_sec == INT64_MIN) {
+    diff = a;
+  } else if (b.tv_sec == INT64_MIN ||
+             (b.tv_sec <= 0 && a.tv_sec >= INT64_MAX + b.tv_sec)) {
+    diff = gpr_inf_future(GPR_CLOCK_REALTIME);
+  } else if (b.tv_sec == INT64_MAX ||
+             (b.tv_sec >= 0 && a.tv_sec <= INT64_MIN + b.tv_sec)) {
+    diff = gpr_inf_past(GPR_CLOCK_REALTIME);
+  } else {
+    diff.tv_sec = a.tv_sec - b.tv_sec;
+    if (dec != 0 && diff.tv_sec == INT64_MIN + 1) {
+      diff = gpr_inf_past(GPR_CLOCK_REALTIME);
+    } else {
+      diff.tv_sec -= dec;
+    }
+  }
+  return diff;
+}
+
+int gpr_time_similar(gpr_timespec a, gpr_timespec b, gpr_timespec threshold) {
+  int cmp_ab;
+
+  GPR_ASSERT(a.clock_type == b.clock_type);
+  GPR_ASSERT(threshold.clock_type == GPR_TIMESPAN);
+
+  cmp_ab = gpr_time_cmp(a, b);
+  if (cmp_ab == 0) return 1;
+  if (cmp_ab < 0) {
+    return gpr_time_cmp(gpr_time_sub(b, a), threshold) <= 0;
+  } else {
+    return gpr_time_cmp(gpr_time_sub(a, b), threshold) <= 0;
+  }
+}
+
+int32_t gpr_time_to_millis(gpr_timespec t) {
+  if (t.tv_sec >= 2147483) {
+    if (t.tv_sec == 2147483 && t.tv_nsec < 648 * GPR_NS_PER_MS) {
+      return 2147483 * GPR_MS_PER_SEC + t.tv_nsec / GPR_NS_PER_MS;
+    }
+    return 2147483647;
+  } else if (t.tv_sec <= -2147483) {
+    /* TODO(ctiller): correct handling here (it's so far in the past do we
+       care?) */
+    return -2147483647;
+  } else {
+    return (int32_t)(t.tv_sec * GPR_MS_PER_SEC + t.tv_nsec / GPR_NS_PER_MS);
+  }
+}
+
+double gpr_timespec_to_micros(gpr_timespec t) {
+  return (double)t.tv_sec * GPR_US_PER_SEC + t.tv_nsec * 1e-3;
+}
+
+gpr_timespec gpr_convert_clock_type(gpr_timespec t, gpr_clock_type clock_type) {
+  if (t.clock_type == clock_type) {
+    return t;
+  }
+
+  if (t.tv_sec == INT64_MAX || t.tv_sec == INT64_MIN) {
+    t.clock_type = clock_type;
+    return t;
+  }
+
+  if (clock_type == GPR_TIMESPAN) {
+    return gpr_time_sub(t, gpr_now(t.clock_type));
+  }
+
+  if (t.clock_type == GPR_TIMESPAN) {
+    return gpr_time_add(gpr_now(clock_type), t);
+  }
+
+  return gpr_time_add(gpr_now(clock_type),
+                      gpr_time_sub(t, gpr_now(t.clock_type)));
+}
diff --git a/src/core/lib/gpr/time_posix.cc b/src/core/lib/gpr/time_posix.cc
new file mode 100644
index 0000000000..9c7e86b080
--- /dev/null
+++ b/src/core/lib/gpr/time_posix.cc
@@ -0,0 +1,166 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+#include "src/core/lib/gpr/time_precise.h"
+
+#ifdef GPR_POSIX_TIME
+
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#ifdef __linux__
+#include <sys/syscall.h>
+#endif
+#include <grpc/support/atm.h>
+#include <grpc/support/log.h>
+#include <grpc/support/time.h>
+
+static struct timespec timespec_from_gpr(gpr_timespec gts) {
+  struct timespec rv;
+  if (sizeof(time_t) < sizeof(int64_t)) {
+    /* fine to assert, as this is only used in gpr_sleep_until */
+    GPR_ASSERT(gts.tv_sec <= INT32_MAX && gts.tv_sec >= INT32_MIN);
+  }
+  rv.tv_sec = (time_t)gts.tv_sec;
+  rv.tv_nsec = gts.tv_nsec;
+  return rv;
+}
+
+#if _POSIX_TIMERS > 0 || defined(__OpenBSD__)
+static gpr_timespec gpr_from_timespec(struct timespec ts,
+                                      gpr_clock_type clock_type) {
+  /*
+   * timespec.tv_sec can have smaller size than gpr_timespec.tv_sec,
+   * but we are only using this function to implement gpr_now
+   * so there's no need to handle "infinity" values.
+   */
+  gpr_timespec rv;
+  rv.tv_sec = ts.tv_sec;
+  rv.tv_nsec = (int32_t)ts.tv_nsec;
+  rv.clock_type = clock_type;
+  return rv;
+}
+
+/** maps gpr_clock_type --> clockid_t for clock_gettime */
+static const clockid_t clockid_for_gpr_clock[] = {CLOCK_MONOTONIC,
+                                                  CLOCK_REALTIME};
+
+void gpr_time_init(void) { gpr_precise_clock_init(); }
+
+static gpr_timespec now_impl(gpr_clock_type clock_type) {
+  struct timespec now;
+  GPR_ASSERT(clock_type != GPR_TIMESPAN);
+  if (clock_type == GPR_CLOCK_PRECISE) {
+    gpr_timespec ret;
+    gpr_precise_clock_now(&ret);
+    return ret;
+  } else {
+#if defined(GPR_BACKWARDS_COMPATIBILITY_MODE) && defined(__linux__)
+    /* avoid ABI problems by invoking syscalls directly */
+    syscall(SYS_clock_gettime, clockid_for_gpr_clock[clock_type], &now);
+#else
+    clock_gettime(clockid_for_gpr_clock[clock_type], &now);
+#endif
+    return gpr_from_timespec(now, clock_type);
+  }
+}
+#else
+  /* For some reason Apple's OSes haven't implemented clock_gettime. */
+
+#include <mach/mach.h>
+#include <mach/mach_time.h>
+#include <sys/time.h>
+
+static double g_time_scale;
+static uint64_t g_time_start;
+
+void gpr_time_init(void) {
+  mach_timebase_info_data_t tb = {0, 1};
+  gpr_precise_clock_init();
+  mach_timebase_info(&tb);
+  g_time_scale = tb.numer;
+  g_time_scale /= tb.denom;
+  g_time_start = mach_absolute_time();
+}
+
+static gpr_timespec now_impl(gpr_clock_type clock) {
+  gpr_timespec now;
+  struct timeval now_tv;
+  double now_dbl;
+
+  now.clock_type = clock;
+  switch (clock) {
+    case GPR_CLOCK_REALTIME:
+      gettimeofday(&now_tv, nullptr);
+      now.tv_sec = now_tv.tv_sec;
+      now.tv_nsec = now_tv.tv_usec * 1000;
+      break;
+    case GPR_CLOCK_MONOTONIC:
+      now_dbl = ((double)(mach_absolute_time() - g_time_start)) * g_time_scale;
+      now.tv_sec = (int64_t)(now_dbl * 1e-9);
+      now.tv_nsec = (int32_t)(now_dbl - ((double)now.tv_sec) * 1e9);
+      break;
+    case GPR_CLOCK_PRECISE:
+      gpr_precise_clock_now(&now);
+      break;
+    case GPR_TIMESPAN:
+      abort();
+  }
+
+  return now;
+}
+#endif
+
+gpr_timespec (*gpr_now_impl)(gpr_clock_type clock_type) = now_impl;
+
+#ifdef GPR_LOW_LEVEL_COUNTERS
+gpr_atm gpr_now_call_count;
+#endif
+
+gpr_timespec gpr_now(gpr_clock_type clock_type) {
+#ifdef GPR_LOW_LEVEL_COUNTERS
+  __atomic_fetch_add(&gpr_now_call_count, 1, __ATOMIC_RELAXED);
+#endif
+  return gpr_now_impl(clock_type);
+}
+
+void gpr_sleep_until(gpr_timespec until) {
+  gpr_timespec now;
+  gpr_timespec delta;
+  struct timespec delta_ts;
+  int ns_result;
+
+  for (;;) {
+    /* We could simplify by using clock_nanosleep instead, but it might be
+     * slightly less portable. */
+    now = gpr_now(until.clock_type);
+    if (gpr_time_cmp(until, now) <= 0) {
+      return;
+    }
+
+    delta = gpr_time_sub(until, now);
+    delta_ts = timespec_from_gpr(delta);
+    ns_result = nanosleep(&delta_ts, nullptr);
+    if (ns_result == 0) {
+      break;
+    }
+  }
+}
+
+#endif /* GPR_POSIX_TIME */
diff --git a/src/core/lib/gpr/time_precise.cc b/src/core/lib/gpr/time_precise.cc
new file mode 100644
index 0000000000..3c7aaabc40
--- /dev/null
+++ b/src/core/lib/gpr/time_precise.cc
@@ -0,0 +1,76 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/log.h>
+#include <grpc/support/time.h>
+#include <stdio.h>
+
+#include "src/core/lib/gpr/time_precise.h"
+
+#ifdef GRPC_TIMERS_RDTSC
+#if defined(__i386__)
+static void gpr_get_cycle_counter(int64_t int* clk) {
+  int64_t int ret;
+  __asm__ volatile("rdtsc" : "=A"(ret));
+  *clk = ret;
+}
+
+// ----------------------------------------------------------------
+#elif defined(__x86_64__) || defined(__amd64__)
+static void gpr_get_cycle_counter(int64_t* clk) {
+  uint64_t low, high;
+  __asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
+  *clk = (int64_t)(high << 32) | (int64_t)low;
+}
+#endif
+
+static double cycles_per_second = 0;
+static int64_t start_cycle;
+void gpr_precise_clock_init(void) {
+  time_t start;
+  int64_t end_cycle;
+  gpr_log(GPR_DEBUG, "Calibrating timers");
+  start = time(NULL);
+  while (time(NULL) == start)
+    ;
+  gpr_get_cycle_counter(&start_cycle);
+  while (time(NULL) <= start + 10)
+    ;
+  gpr_get_cycle_counter(&end_cycle);
+  cycles_per_second = (double)(end_cycle - start_cycle) / 10.0;
+  gpr_log(GPR_DEBUG, "... cycles_per_second = %f\n", cycles_per_second);
+}
+
+void gpr_precise_clock_now(gpr_timespec* clk) {
+  int64_t counter;
+  double secs;
+  gpr_get_cycle_counter(&counter);
+  secs = (double)(counter - start_cycle) / cycles_per_second;
+  clk->clock_type = GPR_CLOCK_PRECISE;
+  clk->tv_sec = (int64_t)secs;
+  clk->tv_nsec = (int32_t)(1e9 * (secs - (double)clk->tv_sec));
+}
+
+#else  /* GRPC_TIMERS_RDTSC */
+void gpr_precise_clock_init(void) {}
+
+void gpr_precise_clock_now(gpr_timespec* clk) {
+  *clk = gpr_now(GPR_CLOCK_REALTIME);
+  clk->clock_type = GPR_CLOCK_PRECISE;
+}
+#endif /* GRPC_TIMERS_RDTSC */
diff --git a/src/core/lib/gpr/time_precise.h b/src/core/lib/gpr/time_precise.h
new file mode 100644
index 0000000000..acc4ee3d1b
--- /dev/null
+++ b/src/core/lib/gpr/time_precise.h
@@ -0,0 +1,27 @@
+/*
+ *
+ * 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_GPR_TIME_PRECISE_H
+#define GRPC_CORE_LIB_GPR_TIME_PRECISE_H
+
+#include <grpc/support/time.h>
+
+void gpr_precise_clock_init(void);
+void gpr_precise_clock_now(gpr_timespec* clk);
+
+#endif /* GRPC_CORE_LIB_GPR_TIME_PRECISE_H */
diff --git a/src/core/lib/gpr/time_windows.cc b/src/core/lib/gpr/time_windows.cc
new file mode 100644
index 0000000000..247cc16468
--- /dev/null
+++ b/src/core/lib/gpr/time_windows.cc
@@ -0,0 +1,98 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/* Win32 code for gpr time support. */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS_TIME
+
+#include <grpc/support/log.h>
+#include <grpc/support/time.h>
+#include <limits.h>
+#include <process.h>
+#include <sys/timeb.h>
+
+#include "src/core/lib/gpr/time_precise.h"
+
+static LARGE_INTEGER g_start_time;
+static double g_time_scale;
+
+void gpr_time_init(void) {
+  LARGE_INTEGER frequency;
+  QueryPerformanceFrequency(&frequency);
+  QueryPerformanceCounter(&g_start_time);
+  g_time_scale = 1.0 / (double)frequency.QuadPart;
+}
+
+static gpr_timespec now_impl(gpr_clock_type clock) {
+  gpr_timespec now_tv;
+  LONGLONG diff;
+  struct _timeb now_tb;
+  LARGE_INTEGER timestamp;
+  double now_dbl;
+  now_tv.clock_type = clock;
+  switch (clock) {
+    case GPR_CLOCK_REALTIME:
+      _ftime_s(&now_tb);
+      now_tv.tv_sec = (int64_t)now_tb.time;
+      now_tv.tv_nsec = now_tb.millitm * 1000000;
+      break;
+    case GPR_CLOCK_MONOTONIC:
+    case GPR_CLOCK_PRECISE:
+      QueryPerformanceCounter(&timestamp);
+      diff = timestamp.QuadPart - g_start_time.QuadPart;
+      now_dbl = (double)diff * g_time_scale;
+      now_tv.tv_sec = (int64_t)now_dbl;
+      now_tv.tv_nsec = (int32_t)((now_dbl - (double)now_tv.tv_sec) * 1e9);
+      break;
+    case GPR_TIMESPAN:
+      abort();
+      break;
+  }
+  return now_tv;
+}
+
+gpr_timespec (*gpr_now_impl)(gpr_clock_type clock_type) = now_impl;
+
+gpr_timespec gpr_now(gpr_clock_type clock_type) {
+  return gpr_now_impl(clock_type);
+}
+
+void gpr_sleep_until(gpr_timespec until) {
+  gpr_timespec now;
+  gpr_timespec delta;
+  int64_t sleep_millis;
+
+  for (;;) {
+    /* We could simplify by using clock_nanosleep instead, but it might be
+     * slightly less portable. */
+    now = gpr_now(until.clock_type);
+    if (gpr_time_cmp(until, now) <= 0) {
+      return;
+    }
+
+    delta = gpr_time_sub(until, now);
+    sleep_millis =
+        delta.tv_sec * GPR_MS_PER_SEC + delta.tv_nsec / GPR_NS_PER_MS;
+    GPR_ASSERT((sleep_millis >= 0) && (sleep_millis <= INT_MAX));
+    Sleep((DWORD)sleep_millis);
+  }
+}
+
+#endif /* GPR_WINDOWS_TIME */
diff --git a/src/core/lib/gpr/tls_pthread.cc b/src/core/lib/gpr/tls_pthread.cc
new file mode 100644
index 0000000000..ebeef2a8c2
--- /dev/null
+++ b/src/core/lib/gpr/tls_pthread.cc
@@ -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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_PTHREAD_TLS
+
+#include <grpc/support/tls.h>
+
+intptr_t gpr_tls_set(struct gpr_pthread_thread_local* tls, intptr_t value) {
+  GPR_ASSERT(0 == pthread_setspecific(tls->key, (void*)value));
+  return value;
+}
+
+#endif /* GPR_PTHREAD_TLS */
diff --git a/src/core/lib/gpr/tmpfile.h b/src/core/lib/gpr/tmpfile.h
new file mode 100644
index 0000000000..f47ec7aa63
--- /dev/null
+++ b/src/core/lib/gpr/tmpfile.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_GPR_TMPFILE_H
+#define GRPC_CORE_LIB_GPR_TMPFILE_H
+
+#include <stdio.h>
+
+/* Creates a temporary file from a prefix.
+   If tmp_filename is not NULL, *tmp_filename is assigned the name of the
+   created file and it is the responsibility of the caller to gpr_free it
+   unless an error occurs in which case it will be set to NULL. */
+FILE* gpr_tmpfile(const char* prefix, char** tmp_filename);
+
+#endif /* GRPC_CORE_LIB_GPR_TMPFILE_H */
diff --git a/src/core/lib/gpr/tmpfile_msys.cc b/src/core/lib/gpr/tmpfile_msys.cc
new file mode 100644
index 0000000000..76cd886f3a
--- /dev/null
+++ b/src/core/lib/gpr/tmpfile_msys.cc
@@ -0,0 +1,58 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_MSYS_TMPFILE
+
+#include <io.h>
+#include <stdio.h>
+#include <string.h>
+#include <tchar.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/gpr/string_windows.h"
+#include "src/core/lib/gpr/tmpfile.h"
+
+FILE* gpr_tmpfile(const char* prefix, char** tmp_filename_out) {
+  FILE* result = NULL;
+  char tmp_filename[MAX_PATH];
+  UINT success;
+
+  if (tmp_filename_out != NULL) *tmp_filename_out = NULL;
+
+  /* Generate a unique filename with our template + temporary path. */
+  success = GetTempFileNameA(".", prefix, 0, tmp_filename);
+  fprintf(stderr, "success = %d\n", success);
+
+  if (success) {
+    /* Open a file there. */
+    result = fopen(tmp_filename, "wb+");
+    fprintf(stderr, "result = %p\n", result);
+  }
+  if (result != NULL && tmp_filename_out) {
+    *tmp_filename_out = gpr_strdup(tmp_filename);
+  }
+
+  return result;
+}
+
+#endif /* GPR_MSYS_TMPFILE */
diff --git a/src/core/lib/gpr/tmpfile_posix.cc b/src/core/lib/gpr/tmpfile_posix.cc
new file mode 100644
index 0000000000..ffdad335d6
--- /dev/null
+++ b/src/core/lib/gpr/tmpfile_posix.cc
@@ -0,0 +1,70 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_TMPFILE
+
+#include "src/core/lib/gpr/tmpfile.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/gpr/string.h"
+
+FILE* gpr_tmpfile(const char* prefix, char** tmp_filename) {
+  FILE* result = nullptr;
+  char* filename_template;
+  int fd;
+
+  if (tmp_filename != nullptr) *tmp_filename = nullptr;
+
+  gpr_asprintf(&filename_template, "/tmp/%s_XXXXXX", prefix);
+  GPR_ASSERT(filename_template != nullptr);
+
+  fd = mkstemp(filename_template);
+  if (fd == -1) {
+    gpr_log(GPR_ERROR, "mkstemp failed for filename_template %s with error %s.",
+            filename_template, strerror(errno));
+    goto end;
+  }
+  result = fdopen(fd, "w+");
+  if (result == nullptr) {
+    gpr_log(GPR_ERROR, "Could not open file %s from fd %d (error = %s).",
+            filename_template, fd, strerror(errno));
+    unlink(filename_template);
+    close(fd);
+    goto end;
+  }
+
+end:
+  if (result != nullptr && tmp_filename != nullptr) {
+    *tmp_filename = filename_template;
+  } else {
+    gpr_free(filename_template);
+  }
+  return result;
+}
+
+#endif /* GPR_POSIX_TMPFILE */
diff --git a/src/core/lib/gpr/tmpfile_windows.cc b/src/core/lib/gpr/tmpfile_windows.cc
new file mode 100644
index 0000000000..d486808418
--- /dev/null
+++ b/src/core/lib/gpr/tmpfile_windows.cc
@@ -0,0 +1,69 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WINDOWS_TMPFILE
+
+#include <io.h>
+#include <stdio.h>
+#include <string.h>
+#include <tchar.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/gpr/string_windows.h"
+#include "src/core/lib/gpr/tmpfile.h"
+
+FILE* gpr_tmpfile(const char* prefix, char** tmp_filename_out) {
+  FILE* result = NULL;
+  LPTSTR template_string = NULL;
+  TCHAR tmp_path[MAX_PATH];
+  TCHAR tmp_filename[MAX_PATH];
+  DWORD status;
+  UINT success;
+
+  if (tmp_filename_out != NULL) *tmp_filename_out = NULL;
+
+  /* Convert our prefix to TCHAR. */
+  template_string = gpr_char_to_tchar(prefix);
+  GPR_ASSERT(template_string);
+
+  /* Get the path to the best temporary folder available. */
+  status = GetTempPath(MAX_PATH, tmp_path);
+  if (status == 0 || status > MAX_PATH) goto end;
+
+  /* Generate a unique filename with our template + temporary path. */
+  success = GetTempFileName(tmp_path, template_string, 0, tmp_filename);
+  if (!success) goto end;
+
+  /* Open a file there. */
+  if (_tfopen_s(&result, tmp_filename, TEXT("wb+")) != 0) goto end;
+
+end:
+  if (result && tmp_filename_out) {
+    *tmp_filename_out = gpr_tchar_to_char(tmp_filename);
+  }
+
+  gpr_free(template_string);
+  return result;
+}
+
+#endif /* GPR_WINDOWS_TMPFILE */
diff --git a/src/core/lib/gpr/wrap_memcpy.cc b/src/core/lib/gpr/wrap_memcpy.cc
new file mode 100644
index 0000000000..9b8608e056
--- /dev/null
+++ b/src/core/lib/gpr/wrap_memcpy.cc
@@ -0,0 +1,42 @@
+/*
+ *
+ * Copyright 2016 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 <grpc/support/port_platform.h>
+
+#include <string.h>
+
+/* Provide a wrapped memcpy for targets that need to be backwards
+ * compatible with older libc's.
+ *
+ * Enable by setting LDFLAGS=-Wl,-wrap,memcpy when linking.
+ */
+
+extern "C" {
+#ifdef __linux__
+#if defined(__x86_64__) && !defined(GPR_MUSL_LIBC_COMPAT)
+__asm__(".symver memcpy,memcpy@GLIBC_2.2.5");
+void* __wrap_memcpy(void* destination, const void* source, size_t num) {
+  return memcpy(destination, source, num);
+}
+#else /* !__x86_64__ */
+void* __wrap_memcpy(void* destination, const void* source, size_t num) {
+  return memmove(destination, source, num);
+}
+#endif
+#endif
+}