Refactor common implementation for health storage HAL.

Create a new library, libhealth_storage_impl_common, that's useful
for common health storage HAL implementation.

Test: TH
Change-Id: I07c51d0b9c2e2262bf327dc3deabc7b41c89355d
diff --git a/health/storage/impl_common/Android.bp b/health/storage/impl_common/Android.bp
new file mode 100644
index 0000000..e1149c0
--- /dev/null
+++ b/health/storage/impl_common/Android.bp
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+// Common implementation between HIDL and AIDL HAL.
+cc_library_static {
+    name: "libhealth_storage_impl_common",
+    vendor: true,
+    srcs: [
+        "impl_common.cpp",
+    ],
+    export_include_dirs: [
+        "include",
+    ],
+
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+
+    shared_libs: [
+        "libbase",
+        "libhidlbase",
+        "liblog",
+        "android.hardware.health.storage@1.0",
+    ],
+
+    static_libs: [
+        "libfstab",
+    ],
+
+    export_shared_lib_headers: [
+        "android.hardware.health.storage@1.0",
+    ],
+}
diff --git a/health/storage/impl_common/impl_common.cpp b/health/storage/impl_common/impl_common.cpp
new file mode 100644
index 0000000..6e753d4
--- /dev/null
+++ b/health/storage/impl_common/impl_common.cpp
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2021 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 <health-storage-impl/common.h>
+
+#include <android-base/chrono_utils.h>
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/strings.h>
+#include <fstab/fstab.h>
+
+using ::android::base::ReadFileToString;
+using ::android::base::Timer;
+using ::android::base::Trim;
+using ::android::base::WriteStringToFd;
+using ::android::base::WriteStringToFile;
+using ::android::fs_mgr::Fstab;
+using ::android::fs_mgr::ReadDefaultFstab;
+using ::android::hardware::health::storage::V1_0::Result;
+
+namespace android::hardware::health::storage {
+
+static std::string GetGarbageCollectPath() {
+    Fstab fstab;
+    ReadDefaultFstab(&fstab);
+
+    for (const auto& entry : fstab) {
+        if (!entry.sysfs_path.empty()) {
+            return entry.sysfs_path + "/manual_gc";
+        }
+    }
+
+    return "";
+}
+
+Result GarbageCollect(uint64_t timeout_seconds) {
+    std::string path = GetGarbageCollectPath();
+
+    if (path.empty()) {
+        LOG(WARNING) << "Cannot find Dev GC path";
+        return Result::UNKNOWN_ERROR;
+    }
+
+    Result result = Result::SUCCESS;
+    Timer timer;
+    LOG(INFO) << "Start Dev GC on " << path;
+    while (1) {
+        std::string require;
+        if (!ReadFileToString(path, &require)) {
+            PLOG(WARNING) << "Reading manual_gc failed in " << path;
+            result = Result::IO_ERROR;
+            break;
+        }
+        require = Trim(require);
+        if (require == "" || require == "off" || require == "disabled") {
+            LOG(DEBUG) << "No more to do Dev GC";
+            break;
+        }
+        LOG(DEBUG) << "Trigger Dev GC on " << path;
+        if (!WriteStringToFile("1", path)) {
+            PLOG(WARNING) << "Start Dev GC failed on " << path;
+            result = Result::IO_ERROR;
+            break;
+        }
+        if (timer.duration() >= std::chrono::seconds(timeout_seconds)) {
+            LOG(WARNING) << "Dev GC timeout";
+            // Timeout is not treated as an error. Try next time.
+            break;
+        }
+        sleep(2);
+    }
+    LOG(INFO) << "Stop Dev GC on " << path;
+    if (!WriteStringToFile("0", path)) {
+        PLOG(WARNING) << "Stop Dev GC failed on " << path;
+        result = Result::IO_ERROR;
+    }
+
+    return result;
+}
+
+void DebugDump(int fd) {
+    std::stringstream output;
+
+    std::string path = GetGarbageCollectPath();
+    if (path.empty()) {
+        output << "Cannot find Dev GC path";
+    } else {
+        std::string require;
+
+        if (ReadFileToString(path, &require)) {
+            output << path << ":" << require << std::endl;
+        }
+
+        if (WriteStringToFile("0", path)) {
+            output << "stop success" << std::endl;
+        }
+    }
+
+    if (!WriteStringToFd(output.str(), fd)) {
+        PLOG(WARNING) << "debug: cannot write to fd";
+    }
+
+    fsync(fd);
+}
+
+}  // namespace android::hardware::health::storage
diff --git a/health/storage/impl_common/include/health-storage-impl/common.h b/health/storage/impl_common/include/health-storage-impl/common.h
new file mode 100644
index 0000000..c84a6a9
--- /dev/null
+++ b/health/storage/impl_common/include/health-storage-impl/common.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#pragma once
+
+#include <android/hardware/health/storage/1.0/types.h>
+#include <string>
+
+namespace android::hardware::health::storage {
+
+// Run debug on fd
+void DebugDump(int fd);
+
+// Run garbage collection on GetGarbageCollectPath(). Blocks until garbage
+// collect finishes or |timeout_seconds| has reached.
+V1_0::Result GarbageCollect(uint64_t timeout_seconds);
+
+}  // namespace android::hardware::health::storage