Make fs_mgr_overlayfs_mount_fstab_entry() available for user builds am: 18a6cc2bac (846c0560) · Commits · e / os / android_system_core

fs_mgr/fs_mgr.cpp

+69 −0

Original line number	Diff line number	Diff line
		@@ -2265,3 +2265,72 @@ std::string fs_mgr_get_super_partition_name(int slot) {
		}
		return LP_METADATA_DEFAULT_PARTITION_NAME;
		}

		bool fs_mgr_mount_overlayfs_fstab_entry(const FstabEntry& entry) {
		auto overlayfs_valid_result = fs_mgr_overlayfs_valid();
		if (overlayfs_valid_result == OverlayfsValidResult::kNotSupported) {
		LERROR << __FUNCTION__ << "(): kernel does not support overlayfs";
		return false;
		}

		#if ALLOW_ADBD_DISABLE_VERITY == 0
		// Allowlist the mount point if user build.
		static const std::vector<const std::string> kAllowedPaths = {
		"/odm", "/odm_dlkm", "/oem", "/product", "/system_ext", "/vendor", "/vendor_dlkm",
		};
		static const std::vector<const std::string> kAllowedPrefixes = {
		"/mnt/product/",
		"/mnt/vendor/",
		};
		if (std::none_of(kAllowedPaths.begin(), kAllowedPaths.end(),
		[&entry](const auto& path) -> bool {
		return entry.mount_point == path \|\|
		StartsWith(entry.mount_point, path + "/");
		}) &&
		std::none_of(kAllowedPrefixes.begin(), kAllowedPrefixes.end(),
		[&entry](const auto& prefix) -> bool {
		return entry.mount_point != prefix &&
		StartsWith(entry.mount_point, prefix);
		})) {
		LERROR << __FUNCTION__
		<< "(): mount point is forbidden on user build: " << entry.mount_point;
		return false;
		}
		#endif // ALLOW_ADBD_DISABLE_VERITY == 0

		// Create the mount point in case it doesn't exist.
		mkdir(entry.mount_point.c_str(), 0755);

		// Ensure that mount point exists and doesn't contain symbolic link or /../.
		std::string mount_point;
		if (!Realpath(entry.mount_point, &mount_point)) {
		PERROR << __FUNCTION__ << "(): failed to realpath " << entry.mount_point;
		return false;
		}
		if (entry.mount_point != mount_point) {
		LERROR << __FUNCTION__ << "(): mount point must be a canonicalized path: realpath "
		<< entry.mount_point << " = " << mount_point;
		return false;
		}

		auto options = "lowerdir=" + entry.lowerdir;
		if (overlayfs_valid_result == OverlayfsValidResult::kOverrideCredsRequired) {
		options += ",override_creds=off";
		}

		// Use "overlay-" + entry.blk_device as the mount() source, so that adb-remout-test don't
		// confuse this with adb remount overlay, whose device name is "overlay".
		// Overlayfs is a pseudo filesystem, so the source device is a symbolic value and isn't used to
		// back the filesystem. However the device name would be shown in /proc/mounts.
		auto source = "overlay-" + entry.blk_device;
		auto report = "__mount(source=" + source + ",target=" + entry.mount_point + ",type=overlay," +
		options + ")=";
		auto ret = mount(source.c_str(), entry.mount_point.c_str(), "overlay", MS_RDONLY \| MS_NOATIME,
		options.c_str());
		if (ret) {
		PERROR << report << ret;
		return false;
		}
		LINFO << report << ret;
		return true;
		}

fs_mgr/fs_mgr_overlayfs.cpp

+0 −32

Original line number	Diff line number	Diff line
		@@ -92,10 +92,6 @@ bool fs_mgr_overlayfs_mount_all(Fstab*) {
		return false;
		}

		bool fs_mgr_overlayfs_mount_fstab_entry(const android::fs_mgr::FstabEntry&) {
		return false;
		}

		std::vector<std::string> fs_mgr_overlayfs_required_devices(Fstab*) {
		return {};
		}
		@@ -1299,34 +1295,6 @@ static void TryMountScratch() {
		}
		}

		bool fs_mgr_overlayfs_mount_fstab_entry(const android::fs_mgr::FstabEntry& entry) {
		if (fs_mgr_overlayfs_invalid()) return false;

		// Create the mount point in case it doesn't exist.
		mkdir(entry.mount_point.c_str(), 0755);

		auto options = kLowerdirOption + entry.lowerdir;
		if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kOverrideCredsRequired) {
		options += ",override_creds=off";
		}

		// Use "overlay-" + entry.blk_device as the mount() source, so that adb-remout-test don't
		// confuse this with adb remount overlay, whose device name is "overlay".
		// Overlayfs is a pseudo filesystem, so the source device is a symbolic value and isn't used to
		// back the filesystem. However the device name would be shown in /proc/mounts.
		auto source = "overlay-" + entry.blk_device;
		auto report = "__mount(source=" + source + ",target=" + entry.mount_point + ",type=overlay," +
		options + ")=";
		auto ret = mount(source.c_str(), entry.mount_point.c_str(), "overlay", MS_RDONLY \| MS_NOATIME,
		options.c_str());
		if (ret) {
		PERROR << report << ret;
		return false;
		}
		LINFO << report << ret;
		return true;
		}

		bool fs_mgr_overlayfs_mount_all(Fstab* fstab) {
		auto ret = false;
		if (fs_mgr_overlayfs_invalid()) return ret;

fs_mgr/include/fs_mgr.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -131,3 +131,8 @@ int fs_mgr_remount_userdata_into_checkpointing(android::fs_mgr::Fstab* fstab);
		// Finds the dm_bow device on which this block device is stacked, or returns
		// empty string
		std::string fs_mgr_find_bow_device(const std::string& block_device);

		// Like fs_mgr_do_mount_one() but for overlayfs fstab entries.
		// Unlike fs_mgr_overlayfs, mount overlayfs without upperdir and workdir, so the
		// filesystem cannot be remount read-write.
		bool fs_mgr_mount_overlayfs_fstab_entry(const android::fs_mgr::FstabEntry& entry);

fs_mgr/include/fs_mgr_overlayfs.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -27,7 +27,6 @@
		android::fs_mgr::Fstab fs_mgr_overlayfs_candidate_list(const android::fs_mgr::Fstab& fstab);

		bool fs_mgr_overlayfs_mount_all(android::fs_mgr::Fstab* fstab);
		bool fs_mgr_overlayfs_mount_fstab_entry(const android::fs_mgr::FstabEntry& entry);
		std::vector<std::string> fs_mgr_overlayfs_required_devices(android::fs_mgr::Fstab* fstab);
		bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_point = nullptr,
		bool* change = nullptr, bool force = true);

init/first_stage_mount.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -574,7 +574,7 @@ bool FirstStageMount::MountPartitions() {

		for (const auto& entry : fstab_) {
		if (entry.fs_type == "overlay") {
		fs_mgr_overlayfs_mount_fstab_entry(entry);
		fs_mgr_mount_overlayfs_fstab_entry(entry);
		}
		}