diff --git a/libcutils/tests/Android.mk b/libcutils/tests/Android.mk
index 4da5ed6..52cf5f4 100644
--- a/libcutils/tests/Android.mk
+++ b/libcutils/tests/Android.mk
@@ -23,8 +23,9 @@
 test_target_only_src_files := \
     MemsetTest.cpp \
     PropertiesTest.cpp \
+    trace-dev_test.cpp \
 
-test_libraries := libcutils liblog
+test_libraries := libcutils liblog libbase
 
 
 #
diff --git a/libcutils/tests/trace-dev_test.cpp b/libcutils/tests/trace-dev_test.cpp
new file mode 100644
index 0000000..edf981b
--- /dev/null
+++ b/libcutils/tests/trace-dev_test.cpp
@@ -0,0 +1,295 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * 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 <sys/types.h>
+#include <unistd.h>
+
+#include <memory>
+#include <string>
+
+#include <android-base/file.h>
+#include <android-base/stringprintf.h>
+#include <android-base/test_utils.h>
+#include <gtest/gtest.h>
+
+#include "../trace-dev.c"
+
+class TraceDevTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    lseek(tmp_file_.fd, 0, SEEK_SET);
+    atrace_marker_fd = tmp_file_.fd;
+  }
+
+  void TearDown() override {
+    atrace_marker_fd = -1;
+  }
+
+  TemporaryFile tmp_file_;
+
+  static std::string MakeName(size_t length) {
+    std::string name;
+    for (size_t i = 0; i < length; i++) {
+      name += '0' + (i % 10);
+    }
+    return name;
+  }
+};
+
+TEST_F(TraceDevTest, atrace_begin_body_normal) {
+  atrace_begin_body("fake_name");
+
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  std::string expected = android::base::StringPrintf("B|%d|fake_name", getpid());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_begin_body_exact) {
+  std::string expected = android::base::StringPrintf("B|%d|", getpid());
+  std::string name = MakeName(ATRACE_MESSAGE_LENGTH - expected.length() - 1);
+  atrace_begin_body(name.c_str());
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  expected += name;
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+
+  // Add a single character and verify we get the exact same value as before.
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  name += '*';
+  atrace_begin_body(name.c_str());
+  EXPECT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_begin_body_truncated) {
+  std::string expected = android::base::StringPrintf("B|%d|", getpid());
+  std::string name = MakeName(2 * ATRACE_MESSAGE_LENGTH);
+  atrace_begin_body(name.c_str());
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  int expected_len = ATRACE_MESSAGE_LENGTH - expected.length() - 1;
+  expected += android::base::StringPrintf("%.*s", expected_len, name.c_str());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_async_begin_body_normal) {
+  atrace_async_begin_body("fake_name", 12345);
+
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  std::string expected = android::base::StringPrintf("S|%d|fake_name|12345", getpid());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_async_begin_body_exact) {
+  std::string expected = android::base::StringPrintf("S|%d|", getpid());
+  std::string name = MakeName(ATRACE_MESSAGE_LENGTH - expected.length() - 7);
+  atrace_async_begin_body(name.c_str(), 12345);
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  expected += name + "|12345";
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+
+  // Add a single character and verify we get the exact same value as before.
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  name += '*';
+  atrace_async_begin_body(name.c_str(), 12345);
+  EXPECT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_async_begin_body_truncated) {
+  std::string expected = android::base::StringPrintf("S|%d|", getpid());
+  std::string name = MakeName(2 * ATRACE_MESSAGE_LENGTH);
+  atrace_async_begin_body(name.c_str(), 12345);
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  int expected_len = ATRACE_MESSAGE_LENGTH - expected.length() - 7;
+  expected += android::base::StringPrintf("%.*s|12345", expected_len, name.c_str());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_async_end_body_normal) {
+  atrace_async_end_body("fake_name", 12345);
+
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  std::string expected = android::base::StringPrintf("F|%d|fake_name|12345", getpid());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_async_end_body_exact) {
+  std::string expected = android::base::StringPrintf("F|%d|", getpid());
+  std::string name = MakeName(ATRACE_MESSAGE_LENGTH - expected.length() - 7);
+  atrace_async_end_body(name.c_str(), 12345);
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  expected += name + "|12345";
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+
+  // Add a single character and verify we get the exact same value as before.
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  name += '*';
+  atrace_async_end_body(name.c_str(), 12345);
+  EXPECT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_async_end_body_truncated) {
+  std::string expected = android::base::StringPrintf("F|%d|", getpid());
+  std::string name = MakeName(2 * ATRACE_MESSAGE_LENGTH);
+  atrace_async_end_body(name.c_str(), 12345);
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  int expected_len = ATRACE_MESSAGE_LENGTH - expected.length() - 7;
+  expected += android::base::StringPrintf("%.*s|12345", expected_len, name.c_str());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_int_body_normal) {
+  atrace_int_body("fake_name", 12345);
+
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  std::string expected = android::base::StringPrintf("C|%d|fake_name|12345", getpid());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_int_body_exact) {
+  std::string expected = android::base::StringPrintf("C|%d|", getpid());
+  std::string name = MakeName(ATRACE_MESSAGE_LENGTH - expected.length() - 7);
+  atrace_int_body(name.c_str(), 12345);
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  expected += name + "|12345";
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+
+  // Add a single character and verify we get the exact same value as before.
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  name += '*';
+  atrace_int_body(name.c_str(), 12345);
+  EXPECT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_int_body_truncated) {
+  std::string expected = android::base::StringPrintf("C|%d|", getpid());
+  std::string name = MakeName(2 * ATRACE_MESSAGE_LENGTH);
+  atrace_int_body(name.c_str(), 12345);
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  int expected_len = ATRACE_MESSAGE_LENGTH - expected.length() - 7;
+  expected += android::base::StringPrintf("%.*s|12345", expected_len, name.c_str());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_int64_body_normal) {
+  atrace_int64_body("fake_name", 17179869183L);
+
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  std::string expected = android::base::StringPrintf("C|%d|fake_name|17179869183", getpid());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_int64_body_exact) {
+  std::string expected = android::base::StringPrintf("C|%d|", getpid());
+  std::string name = MakeName(ATRACE_MESSAGE_LENGTH - expected.length() - 13);
+  atrace_int64_body(name.c_str(), 17179869183L);
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  expected += name + "|17179869183";
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+
+  // Add a single character and verify we get the exact same value as before.
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  name += '*';
+  atrace_int64_body(name.c_str(), 17179869183L);
+  EXPECT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
+
+TEST_F(TraceDevTest, atrace_int64_body_truncated) {
+  std::string expected = android::base::StringPrintf("C|%d|", getpid());
+  std::string name = MakeName(2 * ATRACE_MESSAGE_LENGTH);
+  atrace_int64_body(name.c_str(), 17179869183L);
+
+  ASSERT_EQ(ATRACE_MESSAGE_LENGTH - 1, lseek(atrace_marker_fd, 0, SEEK_CUR));
+  ASSERT_EQ(0, lseek(atrace_marker_fd, 0, SEEK_SET));
+
+  std::string actual;
+  ASSERT_TRUE(android::base::ReadFdToString(atrace_marker_fd, &actual));
+  int expected_len = ATRACE_MESSAGE_LENGTH - expected.length() - 13;
+  expected += android::base::StringPrintf("%.*s|17179869183", expected_len, name.c_str());
+  ASSERT_STREQ(expected.c_str(), actual.c_str());
+}
diff --git a/libcutils/trace-dev.c b/libcutils/trace-dev.c
index f025256..5df1c5a 100644
--- a/libcutils/trace-dev.c
+++ b/libcutils/trace-dev.c
@@ -194,49 +194,47 @@
 void atrace_begin_body(const char* name)
 {
     char buf[ATRACE_MESSAGE_LENGTH];
-    size_t len;
 
-    len = snprintf(buf, ATRACE_MESSAGE_LENGTH, "B|%d|%s", getpid(), name);
+    int len = snprintf(buf, sizeof(buf), "B|%d|%s", getpid(), name);
+    if (len >= (int) sizeof(buf)) {
+        ALOGW("Truncated name in %s: %s\n", __FUNCTION__, name);
+        len = sizeof(buf) - 1;
+    }
     write(atrace_marker_fd, buf, len);
 }
 
+#define WRITE_MSG(format_begin, format_end, pid, name, value) { \
+    char buf[ATRACE_MESSAGE_LENGTH]; \
+    int len = snprintf(buf, sizeof(buf), format_begin "%s" format_end, pid, \
+        name, value); \
+    if (len >= (int) sizeof(buf)) { \
+        /* Given the sizeof(buf), and all of the current format buffers, \
+         * it is impossible for name_len to be < 0 if len >= sizeof(buf). */ \
+        int name_len = strlen(name) - (len - sizeof(buf)) - 1; \
+        /* Truncate the name to make the message fit. */ \
+        ALOGW("Truncated name in %s: %s\n", __FUNCTION__, name); \
+        len = snprintf(buf, sizeof(buf), format_begin "%.*s" format_end, pid, \
+            name_len, name, value); \
+    } \
+    write(atrace_marker_fd, buf, len); \
+}
 
 void atrace_async_begin_body(const char* name, int32_t cookie)
 {
-    char buf[ATRACE_MESSAGE_LENGTH];
-    size_t len;
-
-    len = snprintf(buf, ATRACE_MESSAGE_LENGTH, "S|%d|%s|%" PRId32,
-            getpid(), name, cookie);
-    write(atrace_marker_fd, buf, len);
+    WRITE_MSG("S|%d|", "|%" PRId32, getpid(), name, cookie);
 }
 
 void atrace_async_end_body(const char* name, int32_t cookie)
 {
-    char buf[ATRACE_MESSAGE_LENGTH];
-    size_t len;
-
-    len = snprintf(buf, ATRACE_MESSAGE_LENGTH, "F|%d|%s|%" PRId32,
-            getpid(), name, cookie);
-    write(atrace_marker_fd, buf, len);
+    WRITE_MSG("F|%d|", "|%" PRId32, getpid(), name, cookie);
 }
 
 void atrace_int_body(const char* name, int32_t value)
 {
-    char buf[ATRACE_MESSAGE_LENGTH];
-    size_t len;
-
-    len = snprintf(buf, ATRACE_MESSAGE_LENGTH, "C|%d|%s|%" PRId32,
-            getpid(), name, value);
-    write(atrace_marker_fd, buf, len);
+    WRITE_MSG("C|%d|", "|%" PRId32, getpid(), name, value);
 }
 
 void atrace_int64_body(const char* name, int64_t value)
 {
-    char buf[ATRACE_MESSAGE_LENGTH];
-    size_t len;
-
-    len = snprintf(buf, ATRACE_MESSAGE_LENGTH, "C|%d|%s|%" PRId64,
-            getpid(), name, value);
-    write(atrace_marker_fd, buf, len);
+    WRITE_MSG("C|%d|", "|%" PRId64, getpid(), name, value);
 }