libdm: Add unit tests for dm-linear.

Bug: 110035986
Test: libdm_test gtest
Change-Id: I83fb978931aa36b83880c4d44745cc45ee516fc4

fs_mgr/libdm/Android.bp

@@ -49,5 +49,6 @@ cc_test {
     srcs: [
         "dm_test.cpp",
         "loop_control_test.cpp",
+        "test_util.cpp",
     ]
 }

fs_mgr/libdm/dm_test.cpp

@@ -14,13 +14,29 @@
  * limitations under the License.
  */
 
-#include <map>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
 
+#include <chrono>
+#include <ctime>
+#include <map>
+#include <thread>
+
+#include <android-base/file.h>
+#include <android-base/unique_fd.h>
 #include <gtest/gtest.h>
 #include <libdm/dm.h>
+#include <libdm/loop_control.h>
+#include "test_util.h"
 
 using namespace std;
 using namespace android::dm;
+using unique_fd = android::base::unique_fd;
 
 TEST(libdm, HasMinimumTargets) {
     DeviceMapper& dm = DeviceMapper::Instance();
@@ -35,3 +51,116 @@ TEST(libdm, HasMinimumTargets) {
     auto iter = by_name.find("linear");
     EXPECT_NE(iter, by_name.end());
 }
+
+// Helper to ensure that device mapper devices are released.
+class TempDevice {
+  public:
+    TempDevice(const std::string& name, const DmTable& table)
+        : dm_(DeviceMapper::Instance()), name_(name), valid_(false) {
+        valid_ = dm_.CreateDevice(name, table);
+    }
+    TempDevice(TempDevice&& other) : dm_(other.dm_), name_(other.name_), valid_(other.valid_) {
+        other.valid_ = false;
+    }
+    ~TempDevice() {
+        if (valid_) {
+            dm_.DeleteDevice(name_);
+        }
+    }
+    bool Destroy() {
+        if (!valid_) {
+            return false;
+        }
+        valid_ = false;
+        return dm_.DeleteDevice(name_);
+    }
+    bool WaitForUdev() const {
+        auto start_time = std::chrono::steady_clock::now();
+        while (true) {
+            if (!access(path().c_str(), F_OK)) {
+                return true;
+            }
+            if (errno != ENOENT) {
+                return false;
+            }
+            std::this_thread::sleep_for(50ms);
+            std::chrono::duration elapsed = std::chrono::steady_clock::now() - start_time;
+            if (elapsed >= 5s) {
+                return false;
+            }
+        }
+    }
+    std::string path() const {
+        std::string device_path;
+        if (!dm_.GetDmDevicePathByName(name_, &device_path)) {
+            return "";
+        }
+        return device_path;
+    }
+    const std::string& name() const { return name_; }
+    bool valid() const { return valid_; }
+
+    TempDevice(const TempDevice&) = delete;
+    TempDevice& operator=(const TempDevice&) = delete;
+
+    TempDevice& operator=(TempDevice&& other) {
+        name_ = other.name_;
+        valid_ = other.valid_;
+        other.valid_ = false;
+        return *this;
+    }
+
+  private:
+    DeviceMapper& dm_;
+    std::string name_;
+    bool valid_;
+};
+
+TEST(libdm, DmLinear) {
+    unique_fd tmp1(CreateTempFile("file_1", 4096));
+    ASSERT_GE(tmp1, 0);
+    unique_fd tmp2(CreateTempFile("file_2", 4096));
+    ASSERT_GE(tmp2, 0);
+
+    // Create two different files. These will back two separate loop devices.
+    const char message1[] = "Hello! This is sector 1.";
+    const char message2[] = "Goodbye. This is sector 2.";
+    ASSERT_TRUE(android::base::WriteFully(tmp1, message1, sizeof(message1)));
+    ASSERT_TRUE(android::base::WriteFully(tmp2, message2, sizeof(message2)));
+
+    LoopDevice loop_a(tmp1);
+    ASSERT_TRUE(loop_a.valid());
+    LoopDevice loop_b(tmp2);
+    ASSERT_TRUE(loop_b.valid());
+
+    // Define a 2-sector device, with each sector mapping to the first sector
+    // of one of our loop devices.
+    DmTable table;
+    ASSERT_TRUE(table.AddTarget(make_unique<DmTargetLinear>(0, 1, loop_a.device(), 0)));
+    ASSERT_TRUE(table.AddTarget(make_unique<DmTargetLinear>(1, 1, loop_b.device(), 0)));
+    ASSERT_TRUE(table.valid());
+
+    TempDevice dev("libdm-test-dm-linear", table);
+    ASSERT_TRUE(dev.valid());
+    ASSERT_FALSE(dev.path().empty());
+    ASSERT_TRUE(dev.WaitForUdev());
+
+    // Note: a scope is needed to ensure that there are no open descriptors
+    // when we go to close the device.
+    {
+        unique_fd dev_fd(open(dev.path().c_str(), O_RDWR));
+        ASSERT_GE(dev_fd, 0);
+
+        // Test that each sector of our device is correctly mapped to each loop
+        // device.
+        char sector[512];
+        ASSERT_TRUE(android::base::ReadFully(dev_fd, sector, sizeof(sector)));
+        ASSERT_EQ(strncmp(sector, message1, sizeof(message1)), 0);
+        ASSERT_TRUE(android::base::ReadFully(dev_fd, sector, sizeof(sector)));
+        ASSERT_EQ(strncmp(sector, message2, sizeof(message2)), 0);
+    }
+
+    // Normally the TestDevice destructor would delete this, but at least one
+    // test should ensure that device deletion works.
+    ASSERT_TRUE(dev.Destroy());
+}

fs_mgr/libdm/loop_control_test.cpp

@@ -17,17 +17,16 @@
 #include "libdm/loop_control.h"
 
 #include <fcntl.h>
-#include <linux/memfd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/stat.h>
-#include <sys/syscall.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include <android-base/file.h>
 #include <android-base/unique_fd.h>
 #include <gtest/gtest.h>
+#include "test_util.h"
 
 using namespace std;
 using namespace android::dm;
@@ -36,7 +35,7 @@ using unique_fd = android::base::unique_fd;
 static unique_fd TempFile() {
     // A loop device needs to be at least one sector to actually work, so fill
     // up the file with a message.
-    unique_fd fd(syscall(__NR_memfd_create, "fake_disk", 0));
+    unique_fd fd(CreateTempFile("temp", 0));
     if (fd < 0) {
         return {};
     }

fs_mgr/libdm/test_util.cpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2018 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 <fcntl.h>
+#include <linux/memfd.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "test_util.h"
+
+namespace android {
+namespace dm {
+
+using unique_fd = android::base::unique_fd;
+
+// Create a temporary in-memory file. If size is non-zero, the file will be
+// created with a fixed size.
+unique_fd CreateTempFile(const std::string& name, size_t size) {
+    unique_fd fd(syscall(__NR_memfd_create, name.c_str(), MFD_ALLOW_SEALING));
+    if (fd < 0) {
+        return {};
+    }
+    if (size) {
+        if (ftruncate(fd, size) < 0) {
+            perror("ftruncate");
+            return {};
+        }
+        if (fcntl(fd, F_ADD_SEALS, F_SEAL_GROW | F_SEAL_SHRINK) < 0) {
+            perror("fcntl");
+            return {};
+        }
+    }
+    return fd;
+}
+
+}  // namespace dm
+}  // namespace android

fs_mgr/libdm/test_util.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#ifndef _LIBDM_TEST_UTILS_H_
+#define _LIBDM_TEST_UTILS_H_
+
+#include <android-base/unique_fd.h>
+#include <stddef.h>
+
+#include <string>
+
+namespace android {
+namespace dm {
+
+// Create a temporary in-memory file. If size is non-zero, the file will be
+// created with a fixed size.
+android::base::unique_fd CreateTempFile(const std::string& name, size_t size);
+
+}  // namespace dm
+}  // namespace android
+
+#endif  // _LIBDM_TEST_UTILS_H_