Merge "Refactor MountEmulatedStorage()." (5426a637) · Commits · e / os / android_frameworks_base

core/jni/com_android_internal_os_Zygote.cpp

+41 −29

Original line number	Diff line number	Diff line
		@@ -292,6 +292,7 @@ static std::array<UsapTableEntry, USAP_POOL_SIZE_MAX_LIMIT> gUsapTable;
		static FileDescriptorTable* gOpenFdTable = nullptr;

		// Must match values in com.android.internal.os.Zygote.
		// The order of entries here must be kept in sync with ExternalStorageViews array values.
		enum MountExternalKind {
		MOUNT_EXTERNAL_NONE = 0,
		MOUNT_EXTERNAL_DEFAULT = 1,
		@@ -300,6 +301,18 @@ enum MountExternalKind {
		MOUNT_EXTERNAL_LEGACY = 4,
		MOUNT_EXTERNAL_INSTALLER = 5,
		MOUNT_EXTERNAL_FULL = 6,
		MOUNT_EXTERNAL_COUNT = 7
		};

		// The order of entries here must be kept in sync with MountExternalKind enum values.
		static const std::array<const std::string, MOUNT_EXTERNAL_COUNT> ExternalStorageViews = {
		"", // MOUNT_EXTERNAL_NONE
		"/mnt/runtime/default", // MOUNT_EXTERNAL_DEFAULT
		"/mnt/runtime/read", // MOUNT_EXTERNAL_READ
		"/mnt/runtime/write", // MOUNT_EXTERNAL_WRITE
		"/mnt/runtime/write", // MOUNT_EXTERNAL_LEGACY
		"/mnt/runtime/write", // MOUNT_EXTERNAL_INSTALLER
		"/mnt/runtime/full", // MOUNT_EXTERNAL_FULL
		};

		// Must match values in com.android.internal.os.Zygote.
		@@ -633,6 +646,23 @@ static int UnmountTree(const char* path) {
		return 0;
		}

		static void CreateDir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid,
		fail_fn_t fail_fn) {
		if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) {
		fail_fn(CREATE_ERROR("fs_prepare_dir failed on %s: %s",
		dir.c_str(), strerror(errno)));
		}
		}

		static void BindMount(const std::string& source_dir, const std::string& target_dir,
		fail_fn_t fail_fn) {
		if (TEMP_FAILURE_RETRY(mount(source_dir.c_str(), target_dir.c_str(), nullptr,
		MS_BIND \| MS_REC, nullptr)) == -1) {
		fail_fn(CREATE_ERROR("Failed to mount %s to %s: %s",
		source_dir.c_str(), target_dir.c_str(), strerror(errno)));
		}
		}

		// Create a private mount namespace and bind mount appropriate emulated
		// storage for the given user.
		static void MountEmulatedStorage(uid_t uid, jint mount_mode,
		@@ -641,18 +671,11 @@ static void MountEmulatedStorage(uid_t uid, jint mount_mode,
		// See storage config details at http://source.android.com/tech/storage/
		ATRACE_CALL();

		String8 storage_source;
		if (mount_mode == MOUNT_EXTERNAL_DEFAULT) {
		storage_source = "/mnt/runtime/default";
		} else if (mount_mode == MOUNT_EXTERNAL_READ) {
		storage_source = "/mnt/runtime/read";
		} else if (mount_mode == MOUNT_EXTERNAL_WRITE
		\|\| mount_mode == MOUNT_EXTERNAL_LEGACY
		\|\| mount_mode == MOUNT_EXTERNAL_INSTALLER) {
		storage_source = "/mnt/runtime/write";
		} else if (mount_mode == MOUNT_EXTERNAL_FULL) {
		storage_source = "/mnt/runtime/full";
		} else if (mount_mode == MOUNT_EXTERNAL_NONE && !force_mount_namespace) {
		if (mount_mode < 0 \|\| mount_mode >= MOUNT_EXTERNAL_COUNT) {
		fail_fn(CREATE_ERROR("Unknown mount_mode: %d", mount_mode));
		}

		if (mount_mode == MOUNT_EXTERNAL_NONE && !force_mount_namespace) {
		// Sane default of no storage visible
		return;
		}
		@@ -667,26 +690,15 @@ static void MountEmulatedStorage(uid_t uid, jint mount_mode,
		return;
		}

		if (TEMP_FAILURE_RETRY(mount(storage_source.string(), "/storage", nullptr,
		MS_BIND \| MS_REC \| MS_SLAVE, nullptr)) == -1) {
		fail_fn(CREATE_ERROR("Failed to mount %s to /storage: %s",
		storage_source.string(),
		strerror(errno)));
		}
		const std::string& storage_source = ExternalStorageViews[mount_mode];

		BindMount(storage_source, "/storage", fail_fn);

		// Mount user-specific symlink helper into place
		userid_t user_id = multiuser_get_user_id(uid);
		const String8 user_source(String8::format("/mnt/user/%d", user_id));
		if (fs_prepare_dir(user_source.string(), 0751, 0, 0) == -1) {
		fail_fn(CREATE_ERROR("fs_prepare_dir failed on %s",
		user_source.string()));
		}

		if (TEMP_FAILURE_RETRY(mount(user_source.string(), "/storage/self",
		nullptr, MS_BIND, nullptr)) == -1) {
		fail_fn(CREATE_ERROR("Failed to mount %s to /storage/self: %s",
		user_source.string(), strerror(errno)));
		}
		const std::string user_source = StringPrintf("/mnt/user/%d", user_id);
		CreateDir(user_source, 0751, AID_ROOT, AID_ROOT, fail_fn);
		BindMount(user_source, "/storage/self", fail_fn);
		}

		static bool NeedsNoRandomizeWorkaround() {