Merge branch 'master' into unary_promotion_with_concurrent_poll

15 files changed, 338 insertions, 28 deletions

diff --git a/src/core/httpcli/httpcli.c b/src/core/httpcli/httpcli.c
index d372e694e9..d2cf09a8df 100644
--- a/src/core/httpcli/httpcli.c
+++ b/src/core/httpcli/httpcli.c
@@ -216,6 +216,7 @@ static void on_resolved(void *arg, grpc_resolved_addresses *addresses) {
   gpr_log(GPR_DEBUG, "%s", __FUNCTION__);
   if (!addresses) {
     finish(req, 0);
+    return;
   }
   req->addresses = addresses;
   req->next_address = 0;
diff --git a/src/core/json/json.c b/src/core/json/json.c
index df7108a94d..96e11eebb1 100644
--- a/src/core/json/json.c
+++ b/src/core/json/json.c
@@ -38,8 +38,8 @@
 #include "src/core/json/json.h"
 
 grpc_json *grpc_json_create(grpc_json_type type) {
-  grpc_json *json = gpr_malloc(sizeof(grpc_json));
-  memset(json, 0, sizeof(grpc_json));
+  grpc_json *json = gpr_malloc(sizeof(*json));
+  memset(json, 0, sizeof(*json));
   json->type = type;
 
   return json;
diff --git a/src/core/json/json_reader.c b/src/core/json/json_reader.c
index 774faa5f23..5ea4e9569c 100644
--- a/src/core/json/json_reader.c
+++ b/src/core/json/json_reader.c
@@ -93,7 +93,7 @@ static void json_reader_set_null(grpc_json_reader* reader) {
 /* Call this function to initialize the reader structure. */
 void grpc_json_reader_init(grpc_json_reader* reader,
                            grpc_json_reader_vtable* vtable, void* userdata) {
-  memset(reader, 0, sizeof(grpc_json_reader));
+  memset(reader, 0, sizeof(*reader));
   reader->vtable = vtable;
   reader->userdata = userdata;
   json_reader_string_clear(reader);
diff --git a/src/core/json/json_writer.c b/src/core/json/json_writer.c
index 4c0bf30780..a40bf1733e 100644
--- a/src/core/json/json_writer.c
+++ b/src/core/json/json_writer.c
@@ -51,7 +51,7 @@ static void json_writer_output_string_with_len(grpc_json_writer* writer, const c
 
 void grpc_json_writer_init(grpc_json_writer* writer, int indent,
                            grpc_json_writer_vtable* vtable, void* userdata) {
-  memset(writer, 0, sizeof(grpc_json_writer));
+  memset(writer, 0, sizeof(*writer));
   writer->container_empty = 1;
   writer->indent = indent;
   writer->vtable = vtable;
@@ -77,7 +77,7 @@ static void json_writer_output_indent(
 
   while (spaces >= (sizeof(spacesstr) - 1)) {
     json_writer_output_string_with_len(writer, spacesstr,
-                                            sizeof(spacesstr) - 1);
+                                       sizeof(spacesstr) - 1);
     spaces -= (sizeof(spacesstr) - 1);
   }
 
@@ -117,10 +117,10 @@ static void json_writer_escape_string(grpc_json_writer* writer,
     gpr_uint8 c = (gpr_uint8)*string++;
     if (c == 0) {
       break;
-    } else if ((c >= 32) && (c <= 127)) {
+    } else if ((c >= 32) && (c <= 126)) {
       if ((c == '\\') || (c == '"')) json_writer_output_char(writer, '\\');
       json_writer_output_char(writer, c);
-    } else if (c < 32) {
+    } else if ((c < 32) || (c == 127)) {
       switch (c) {
         case '\b':
           json_writer_output_string_with_len(writer, "\\b", 2);
@@ -161,6 +161,7 @@ static void json_writer_escape_string(grpc_json_writer* writer,
       for (i = 0; i < extra; i++) {
         utf32 <<= 6;
         c = *string++;
+        /* Breaks out and bail on any invalid UTF-8 sequence, including \0. */
         if ((c & 0xc0) != 0x80) {
           valid = 0;
           break;
diff --git a/src/core/security/auth.c b/src/core/security/auth.c
index 92878e3b7e..9b67d59cb8 100644
--- a/src/core/security/auth.c
+++ b/src/core/security/auth.c
@@ -234,6 +234,9 @@ static void destroy_call_elem(grpc_call_element *elem) {
   if (calld->host != NULL) {
     grpc_mdstr_unref(calld->host);
   }
+  if (calld->method != NULL) {
+    grpc_mdstr_unref(calld->method);
+  }
 }
 
 /* Constructor for channel_data */
@@ -276,6 +279,9 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
   if (channeld->error_msg_key != NULL) {
     grpc_mdstr_unref(channeld->error_msg_key);
   }
+  if (channeld->path_string != NULL) {
+    grpc_mdstr_unref(channeld->path_string);
+  }
 }
 
 const grpc_channel_filter grpc_client_auth_filter = {
diff --git a/src/core/security/credentials.c b/src/core/security/credentials.c
index 42d1a900fc..7e72b238c8 100644
--- a/src/core/security/credentials.c
+++ b/src/core/security/credentials.c
@@ -1076,7 +1076,3 @@ grpc_credentials *grpc_iam_credentials_create(const char *token,
       c->md_ctx, GRPC_IAM_AUTHORITY_SELECTOR_METADATA_KEY, authority_selector);
   return &c->base;
 }
-
-/* -- Default credentials TODO(jboeuf). -- */
-
-grpc_credentials *grpc_default_credentials_create(void) { return NULL; }
diff --git a/src/core/security/credentials.h b/src/core/security/credentials.h
index 7b8929492b..0a0074c1d5 100644
--- a/src/core/security/credentials.h
+++ b/src/core/security/credentials.h
@@ -60,8 +60,15 @@ typedef enum {
   "x-goog-iam-authorization-token"
 #define GRPC_IAM_AUTHORITY_SELECTOR_METADATA_KEY "x-goog-iam-authority-selector"
 
+#define GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY "gcloud"
+#define GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE \
+  "application_default_credentials.json"
+
 /* --- grpc_credentials. --- */
 
+/* It is the caller's responsibility to gpr_free the result if not NULL. */
+char *grpc_get_well_known_google_credentials_file_path(void);
+
 typedef void (*grpc_credentials_metadata_cb)(void *user_data,
                                              grpc_mdelem **md_elems,
                                              size_t num_md,
diff --git a/src/core/security/credentials_posix.c b/src/core/security/credentials_posix.c
new file mode 100644
index 0000000000..79622cb024
--- /dev/null
+++ b/src/core/security/credentials_posix.c
@@ -0,0 +1,60 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_POSIX_FILE
+
+#include "src/core/security/credentials.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/support/env.h"
+#include "src/core/support/string.h"
+
+char *grpc_get_well_known_google_credentials_file_path(void) {
+  char *result = NULL;
+  char *home = gpr_getenv("HOME");
+  if (home == NULL) {
+    gpr_log(GPR_ERROR, "Could not get HOME environment variable.");
+    return NULL;
+  }
+  gpr_asprintf(&result, "%s/.config/%s/%s", home,
+               GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY,
+               GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE);
+  gpr_free(home);
+  return result;
+}
+
+#endif /* GPR_POSIX_FILE */
diff --git a/src/core/security/credentials_win32.c b/src/core/security/credentials_win32.c
new file mode 100644
index 0000000000..ddb310468b
--- /dev/null
+++ b/src/core/security/credentials_win32.c
@@ -0,0 +1,60 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_WIN32
+
+#include "src/core/security/credentials.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/support/env.h"
+#include "src/core/support/string.h"
+
+char *grpc_get_well_known_google_credentials_file_path(void) {
+  char *result = NULL;
+  char *appdata_path = gpr_getenv("APPDATA");
+  if (appdata_path == NULL) {
+    gpr_log(GPR_ERROR, "Could not get APPDATA environment variable.");
+    return NULL;
+  }
+  gpr_asprintf(&result, "%s/%s/%s", appdata_path,
+               GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY,
+               GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE);
+  gpr_free(appdata_path);
+  return result;
+}
+
+#endif /* GPR_WIN32 */
diff --git a/src/core/security/google_default_credentials.c b/src/core/security/google_default_credentials.c
new file mode 100644
index 0000000000..dc0e453b87
--- /dev/null
+++ b/src/core/security/google_default_credentials.c
@@ -0,0 +1,185 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/security/credentials.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+
+#include "src/core/httpcli/httpcli.h"
+#include "src/core/support/env.h"
+#include "src/core/support/file.h"
+
+/* -- Constants. -- */
+
+#define GRPC_COMPUTE_ENGINE_DETECTION_HOST "metadata.google.internal"
+#define GRPC_GOOGLE_CREDENTIALS_ENV_VAR "GOOGLE_APPLICATION_CREDENTIALS"
+
+/* -- Default credentials. -- */
+
+static grpc_credentials *default_credentials = NULL;
+static int compute_engine_detection_done = 0;
+static gpr_mu g_mu;
+static gpr_once g_once = GPR_ONCE_INIT;
+
+static void init_default_credentials(void) {
+  gpr_mu_init(&g_mu);
+}
+
+typedef struct {
+  gpr_cv cv;
+  gpr_mu mu;
+  int is_done;
+  int success;
+} compute_engine_detector;
+
+static void on_compute_engine_detection_http_response(
+    void *user_data, const grpc_httpcli_response *response) {
+  compute_engine_detector *detector = (compute_engine_detector *)user_data;
+  if (response != NULL && response->status == 200 && response->hdr_count > 0) {
+    /* Internet providers can return a generic response to all requests, so
+       it is necessary to check that metadata header is present also. */
+    size_t i;
+    for (i = 0; i < response->hdr_count; i++) {
+      grpc_httpcli_header *header = &response->hdrs[i];
+      if (!strcmp(header->key, "Metadata-Flavor") &&
+          !strcmp(header->value, "Google")) {
+        detector->success = 1;
+        break;
+      }
+    }
+  }
+  gpr_mu_lock(&detector->mu);
+  detector->is_done = 1;
+  gpr_mu_unlock(&detector->mu);
+  gpr_cv_signal(&detector->cv);
+}
+
+static int is_stack_running_on_compute_engine(void) {
+  compute_engine_detector detector;
+  grpc_httpcli_request request;
+
+  /* The http call is local. If it takes more than one sec, it is for sure not
+     on compute engine. */
+  gpr_timespec max_detection_delay = {1, 0};
+
+  gpr_mu_init(&detector.mu);
+  gpr_cv_init(&detector.cv);
+  detector.is_done = 0;
+  detector.success = 0;
+
+  memset(&request, 0, sizeof(grpc_httpcli_request));
+  request.host = GRPC_COMPUTE_ENGINE_DETECTION_HOST;
+  request.path = "/";
+
+  grpc_httpcli_get(&request, gpr_time_add(gpr_now(), max_detection_delay),
+                   on_compute_engine_detection_http_response, &detector);
+
+  /* Block until we get the response. This is not ideal but this should only be
+     called once for the lifetime of the process by the default credentials. */
+  gpr_mu_lock(&detector.mu);
+  while (!detector.is_done) {
+    gpr_cv_wait(&detector.cv, &detector.mu, gpr_inf_future);
+  }
+  gpr_mu_unlock(&detector.mu);
+
+  gpr_mu_destroy(&detector.mu);
+  gpr_cv_destroy(&detector.cv);
+  return detector.success;
+}
+
+/* Takes ownership of creds_path if not NULL. */
+static grpc_credentials *create_jwt_creds_from_path(char *creds_path) {
+  grpc_credentials *result = NULL;
+  gpr_slice creds_data;
+  int file_ok = 0;
+  if (creds_path == NULL) return NULL;
+  creds_data = gpr_load_file(creds_path, &file_ok);
+  gpr_free(creds_path);
+  if (file_ok) {
+    result = grpc_jwt_credentials_create(
+        (const char *)GPR_SLICE_START_PTR(creds_data),
+        grpc_max_auth_token_lifetime);
+    gpr_slice_unref(creds_data);
+  }
+  return result;
+}
+
+grpc_credentials *grpc_google_default_credentials_create(void) {
+  grpc_credentials *result = NULL;
+  int serving_cached_credentials = 0;
+  gpr_once_init(&g_once, init_default_credentials);
+
+  gpr_mu_lock(&g_mu);
+
+  if (default_credentials != NULL) {
+    result = default_credentials;
+    serving_cached_credentials = 1;
+    goto end;
+  }
+
+  /* First, try the environment variable. */
+  result =
+      create_jwt_creds_from_path(gpr_getenv(GRPC_GOOGLE_CREDENTIALS_ENV_VAR));
+  if (result != NULL) goto end;
+
+  /* Then the well-known file. */
+  result = create_jwt_creds_from_path(
+      grpc_get_well_known_google_credentials_file_path());
+  if (result != NULL) goto end;
+
+  /* At last try to see if we're on compute engine (do the detection only once
+     since it requires a network test). */
+  if (!compute_engine_detection_done) {
+    int need_compute_engine_creds = is_stack_running_on_compute_engine();
+    compute_engine_detection_done = 1;
+    if (need_compute_engine_creds) {
+      result = grpc_compute_engine_credentials_create();
+    }
+  }
+
+end:
+  if (!serving_cached_credentials && result != NULL) {
+    /* Blend with default ssl credentials and add a global reference so that it
+       can be cached and re-served. */
+    result = grpc_composite_credentials_create(
+        grpc_ssl_credentials_create(NULL, NULL), result);
+    GPR_ASSERT(result != NULL);
+    default_credentials = grpc_credentials_ref(result);
+  }
+  gpr_mu_unlock(&g_mu);
+  return result;
+}
diff --git a/src/core/security/security_context.c b/src/core/security/security_context.c
index fd8baff539..9dce5af740 100644
--- a/src/core/security/security_context.c
+++ b/src/core/security/security_context.c
@@ -641,9 +641,3 @@ grpc_channel *grpc_secure_channel_create_with_factories(
           creds->type);
   return grpc_lame_client_channel_create();
 }
-
-grpc_channel *grpc_default_secure_channel_create(
-    const char *target, const grpc_channel_args *args) {
-  return grpc_secure_channel_create(grpc_default_credentials_create(), target,
-                                    args);
-}
diff --git a/src/core/support/log_win32.c b/src/core/support/log_win32.c
index cff130ae18..720dc141f5 100644
--- a/src/core/support/log_win32.c
+++ b/src/core/support/log_win32.c
@@ -90,7 +90,7 @@ void gpr_default_log(gpr_log_func_args *args) {
     strcpy(time_buffer, "error:strftime");
   }
 
-  fprintf(stderr, "%s%s.%09u %5u %s:%d: %s\n",
+  fprintf(stderr, "%s%s.%09u %5u %s:%d] %s\n",
           gpr_log_severity_string(args->severity), time_buffer,
           (int)(now.tv_nsec), GetCurrentThreadId(),
           args->file, args->line, args->message);
diff --git a/src/core/support/string_posix.c b/src/core/support/string_posix.c
index 8a678b3103..25c333db4e 100644
--- a/src/core/support/string_posix.c
+++ b/src/core/support/string_posix.c
@@ -51,7 +51,7 @@ int gpr_asprintf(char **strp, const char *format, ...) {
   va_start(args, format);
   ret = vsnprintf(buf, sizeof(buf), format, args);
   va_end(args);
-  if (!(0 <= ret)) {
+  if (ret < 0) {
     *strp = NULL;
     return -1;
   }
diff --git a/src/core/support/sync.c b/src/core/support/sync.c
index 1a5cf57c4f..ccfe1e25f4 100644
--- a/src/core/support/sync.c
+++ b/src/core/support/sync.c
@@ -41,7 +41,7 @@
    Should be a prime. */
 enum { event_sync_partitions = 31 };
 
-/* Event are partitioned by address to avoid lock contention. */
+/* Events are partitioned by address to avoid lock contention. */
 static struct sync_array_s {
   gpr_mu mu;
   gpr_cv cv;
@@ -71,10 +71,10 @@ 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_ASSERT(value != NULL);
   gpr_atm_rel_store(&ev->state, (gpr_atm)value);
   gpr_cv_broadcast(&s->cv);
   gpr_mu_unlock(&s->mu);
+  GPR_ASSERT(value != NULL);
 }
 
 void *gpr_event_get(gpr_event *ev) {
diff --git a/src/core/support/time.c b/src/core/support/time.c
index 67f7665650..7dbf95059f 100644
--- a/src/core/support/time.c
+++ b/src/core/support/time.c
@@ -85,12 +85,12 @@ gpr_timespec gpr_time_from_nanos(long ns) {
   } else if (ns == LONG_MIN) {
     result = gpr_inf_past;
   } else if (ns >= 0) {
-    result.tv_sec = ns / 1000000000;
-    result.tv_nsec = ns - result.tv_sec * 1000000000;
+    result.tv_sec = ns / GPR_NS_PER_SEC;
+    result.tv_nsec = ns - result.tv_sec * GPR_NS_PER_SEC;
   } else {
     /* Calculation carefully formulated to avoid any possible under/overflow. */
-    result.tv_sec = (-(999999999 - (ns + 1000000000)) / 1000000000) - 1;
-    result.tv_nsec = ns - result.tv_sec * 1000000000;
+    result.tv_sec = (-(999999999 - (ns + GPR_NS_PER_SEC)) / GPR_NS_PER_SEC) - 1;
+    result.tv_nsec = ns - result.tv_sec * GPR_NS_PER_SEC;
   }
   return result;
 }
@@ -172,8 +172,8 @@ gpr_timespec gpr_time_add(gpr_timespec a, gpr_timespec b) {
   gpr_timespec sum;
   int inc = 0;
   sum.tv_nsec = a.tv_nsec + b.tv_nsec;
-  if (sum.tv_nsec >= 1000000000) {
-    sum.tv_nsec -= 1000000000;
+  if (sum.tv_nsec >= GPR_NS_PER_SEC) {
+    sum.tv_nsec -= GPR_NS_PER_SEC;
     inc++;
   }
   if (a.tv_sec == TYPE_MAX(time_t) || a.tv_sec == TYPE_MIN(time_t)) {
@@ -200,7 +200,7 @@ gpr_timespec gpr_time_sub(gpr_timespec a, gpr_timespec b) {
   int dec = 0;
   diff.tv_nsec = a.tv_nsec - b.tv_nsec;
   if (diff.tv_nsec < 0) {
-    diff.tv_nsec += 1000000000;
+    diff.tv_nsec += GPR_NS_PER_SEC;
     dec++;
   }
   if (a.tv_sec == TYPE_MAX(time_t) || a.tv_sec == TYPE_MIN(time_t)) {