Add basic tests for ashmem

Test: CL only adds tests. Ran them to confirm they pass.
Change-Id: Iccc3edaeeabff27f23b3786c3d40b2eb5b02dc83
Signed-off-by: Connor O'Brien <connoro@google.com>
diff --git a/libcutils/tests/Android.bp b/libcutils/tests/Android.bp
index ada7d5f..06d0e28 100644
--- a/libcutils/tests/Android.bp
+++ b/libcutils/tests/Android.bp
@@ -19,6 +19,7 @@
     target: {
         android: {
             srcs: [
+                "AshmemTest.cpp",
                 "MemsetTest.cpp",
                 "PropertiesTest.cpp",
                 "sched_policy_test.cpp",
diff --git a/libcutils/tests/AshmemTest.cpp b/libcutils/tests/AshmemTest.cpp
new file mode 100644
index 0000000..51c679f
--- /dev/null
+++ b/libcutils/tests/AshmemTest.cpp
@@ -0,0 +1,177 @@
+/*
+ * 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/mman.h>
+#include <cutils/ashmem.h>
+#include <gtest/gtest.h>
+#include <android-base/unique_fd.h>
+
+using android::base::unique_fd;
+
+void TestCreateRegion(size_t size, unique_fd &fd, int prot) {
+    fd = unique_fd(ashmem_create_region(nullptr, size));
+    ASSERT_TRUE(fd >= 0);
+    ASSERT_TRUE(ashmem_valid(fd));
+    ASSERT_EQ(size, static_cast<size_t>(ashmem_get_size_region(fd)));
+    ASSERT_EQ(0, ashmem_set_prot_region(fd, prot));
+}
+
+void TestMmap(const unique_fd &fd, size_t size, int prot, void **region) {
+    *region = mmap(nullptr, size, prot, MAP_SHARED, fd, 0);
+    ASSERT_NE(MAP_FAILED, *region);
+}
+
+void TestProtDenied(const unique_fd &fd, size_t size, int prot) {
+    EXPECT_EQ(MAP_FAILED, mmap(nullptr, size, prot, MAP_SHARED, fd, 0));
+}
+
+void FillData(uint8_t* data, size_t dataLen) {
+    for (size_t i = 0; i < dataLen; i++) {
+        data[i] = i & 0xFF;
+    }
+}
+
+TEST(AshmemTest, BasicTest) {
+    constexpr size_t size = PAGE_SIZE;
+    uint8_t data[size];
+    FillData(data, size);
+
+    unique_fd fd;
+    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
+
+    void *region1;
+    ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ | PROT_WRITE, &region1));
+
+    memcpy(region1, &data, size);
+    ASSERT_EQ(0, memcmp(region1, &data, size));
+
+    EXPECT_EQ(0, munmap(region1, size));
+
+    void *region2;
+    ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ, &region2));
+    ASSERT_EQ(0, memcmp(region2, &data, size));
+    EXPECT_EQ(0, munmap(region2, size));
+}
+
+TEST(AshmemTest, ForkTest) {
+    constexpr size_t size = PAGE_SIZE;
+    uint8_t data[size];
+    FillData(data, size);
+
+    unique_fd fd;
+    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
+
+    void *region1;
+    ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ | PROT_WRITE, &region1));
+
+    memcpy(region1, &data, size);
+    ASSERT_EQ(0, memcmp(region1, &data, size));
+    EXPECT_EQ(0, munmap(region1, size));
+
+    ASSERT_EXIT({
+        void *region2 = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+        if (region2 == MAP_FAILED) {
+            _exit(1);
+        }
+        if (memcmp(region2, &data, size) != 0) {
+            _exit(2);
+        }
+        memset(region2, 0, size);
+        munmap(region2, size);
+        _exit(0);
+    }, ::testing::ExitedWithCode(0),"");
+
+    memset(&data, 0, size);
+    void *region2;
+    ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ | PROT_WRITE, &region2));
+    ASSERT_EQ(0, memcmp(region2, &data, size));
+    EXPECT_EQ(0, munmap(region2, size));
+}
+
+TEST(AshmemTest, ProtTest) {
+    unique_fd fd;
+    constexpr size_t size = PAGE_SIZE;
+    void *region;
+
+    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ));
+    TestProtDenied(fd, size, PROT_WRITE);
+    ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ, &region));
+    EXPECT_EQ(0, munmap(region, size));
+
+    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_WRITE));
+    TestProtDenied(fd, size, PROT_READ);
+    ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_WRITE, &region));
+    EXPECT_EQ(0, munmap(region, size));
+}
+
+TEST(AshmemTest, ForkProtTest) {
+    unique_fd fd;
+    constexpr size_t size = PAGE_SIZE;
+
+    int protFlags[] = { PROT_READ, PROT_WRITE };
+    for (int i = 0; i < 2; i++) {
+        ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
+        ASSERT_EXIT({
+            if (ashmem_set_prot_region(fd, protFlags[i]) >= 0) {
+                _exit(0);
+            } else {
+                _exit(1);
+            }
+        }, ::testing::ExitedWithCode(0), "");
+        ASSERT_NO_FATAL_FAILURE(TestProtDenied(fd, size, protFlags[1-i]));
+    }
+}
+
+TEST(AshmemTest, ForkMultiRegionTest) {
+    constexpr size_t size = PAGE_SIZE;
+    uint8_t data[size];
+    FillData(data, size);
+
+    constexpr int nRegions = 16;
+    unique_fd fd[nRegions];
+    for (int i = 0; i < nRegions; i++) {
+        ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd[i], PROT_READ | PROT_WRITE));
+        void *region;
+        ASSERT_NO_FATAL_FAILURE(TestMmap(fd[i], size, PROT_READ | PROT_WRITE, &region));
+        memcpy(region, &data, size);
+        ASSERT_EQ(0, memcmp(region, &data, size));
+        EXPECT_EQ(0, munmap(region, size));
+    }
+
+    ASSERT_EXIT({
+        for (int i = 0; i < nRegions; i++) {
+            void *region = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd[i], 0);
+            if (region == MAP_FAILED) {
+                _exit(1);
+            }
+            if (memcmp(region, &data, size) != 0) {
+                munmap(region, size);
+                _exit(2);
+            }
+            memset(region, 0, size);
+            munmap(region, size);
+        }
+        _exit(0);
+    }, ::testing::ExitedWithCode(0), "");
+
+    memset(&data, 0, size);
+    for (int i = 0; i < nRegions; i++) {
+        void *region;
+        ASSERT_NO_FATAL_FAILURE(TestMmap(fd[i], size, PROT_READ | PROT_WRITE, &region));
+        ASSERT_EQ(0, memcmp(region, &data, size));
+        EXPECT_EQ(0, munmap(region, size));
+    }
+}