Merge "remount: Refactor partition filtering into helper functions." (89d84e1d) · Commits · e / os / android_system_core

fs_mgr/fs_mgr_remount.cpp

+96 −65

Original line number	Diff line number	Diff line
		@@ -43,6 +43,8 @@
		#include <libgsi/libgsid.h>

		using namespace std::literals;
		using android::fs_mgr::Fstab;
		using android::fs_mgr::FstabEntry;

		namespace {

		@@ -62,22 +64,12 @@ namespace {
		::exit(exit_status);
		}

		bool remountable_partition(const android::fs_mgr::FstabEntry& entry) {
		if (entry.fs_mgr_flags.vold_managed) return false;
		if (entry.fs_mgr_flags.recovery_only) return false;
		if (entry.fs_mgr_flags.slot_select_other) return false;
		if (!(entry.flags & MS_RDONLY)) return false;
		if (entry.fs_type == "vfat") return false;
		return true;
		}

		const std::string system_mount_point(const android::fs_mgr::FstabEntry& entry) {
		if (entry.mount_point == "/") return "/system";
		return entry.mount_point;
		}

		const android::fs_mgr::FstabEntry* is_wrapped(const android::fs_mgr::Fstab& overlayfs_candidates,
		const android::fs_mgr::FstabEntry& entry) {
		const FstabEntry* GetWrappedEntry(const Fstab& overlayfs_candidates, const FstabEntry& entry) {
		auto mount_point = system_mount_point(entry);
		auto it = std::find_if(overlayfs_candidates.begin(), overlayfs_candidates.end(),
		[&mount_point](const auto& entry) {
		@@ -188,6 +180,87 @@ static RemountStatus VerifyCheckpointing() {
		return REMOUNT_SUCCESS;
		}

		static bool IsRemountable(Fstab& candidates, const FstabEntry& entry) {
		if (entry.fs_mgr_flags.vold_managed \|\| entry.fs_mgr_flags.recovery_only \|\|
		entry.fs_mgr_flags.slot_select_other) {
		return false;
		}
		if (!(entry.flags & MS_RDONLY)) {
		return false;
		}
		if (entry.fs_type == "vfat") {
		return false;
		}
		if (GetEntryForMountPoint(&candidates, entry.mount_point)) {
		return true;
		}
		if (GetWrappedEntry(candidates, entry)) {
		return false;
		}
		return true;
		}

		static Fstab::const_iterator FindPartition(const Fstab& fstab, const std::string& partition) {
		for (auto iter = fstab.begin(); iter != fstab.end(); iter++) {
		const auto mount_point = system_mount_point(*iter);
		if (partition == mount_point) {
		return iter;
		}
		if (partition == android::base::Basename(mount_point)) {
		return iter;
		}
		}
		return fstab.end();
		}

		static Fstab GetAllRemountablePartitions(Fstab& fstab) {
		auto candidates = fs_mgr_overlayfs_candidate_list(fstab);

		Fstab partitions;
		for (const auto& entry : fstab) {
		if (IsRemountable(candidates, entry)) {
		partitions.emplace_back(entry);
		}
		}
		return partitions;
		}

		static RemountStatus GetRemountList(const Fstab& fstab, const std::vector<std::string>& argv,
		Fstab* partitions) {
		auto candidates = fs_mgr_overlayfs_candidate_list(fstab);

		for (const auto& arg : argv) {
		std::string partition = arg;
		if (partition == "/") {
		partition = "/system";
		}

		auto it = FindPartition(fstab, partition);
		if (it == fstab.end()) {
		LOG(ERROR) << "Unknown partition " << arg;
		return UNKNOWN_PARTITION;
		}

		const FstabEntry* entry = &*it;
		if (auto wrap = GetWrappedEntry(candidates, *entry); wrap != nullptr) {
		LOG(INFO) << "partition " << arg << " covered by overlayfs for " << wrap->mount_point
		<< ", switching";
		entry = wrap;
		}

		if (!IsRemountable(candidates, *entry)) {
		LOG(ERROR) << "Invalid partition " << arg;
		return INVALID_PARTITION;
		}
		if (GetEntryForMountPoint(partitions, entry->mount_point) != nullptr) {
		continue;
		}
		partitions->emplace_back(*entry);
		}

		return REMOUNT_SUCCESS;
		}

		static int do_remount(int argc, char* argv[]) {
		RemountStatus retval = REMOUNT_SUCCESS;

		@@ -201,6 +274,7 @@ static int do_remount(int argc, char* argv[]) {

		const char* fstab_file = nullptr;
		auto can_reboot = false;
		std::vector<std::string> partition_args;

		struct option longopts[] = {
		{"fstab", required_argument, nullptr, 'T'},
		@@ -237,6 +311,10 @@ static int do_remount(int argc, char* argv[]) {
		}
		}

		for (; argc > optind; ++optind) {
		partition_args.emplace_back(argv[optind]);
		}

		// Make sure we are root.
		if (::getuid() != 0) {
		LOG(ERROR) << "Not running as root. Try \"adb root\" first.";
		@@ -244,7 +322,7 @@ static int do_remount(int argc, char* argv[]) {
		}

		// Read the selected fstab.
		android::fs_mgr::Fstab fstab;
		Fstab fstab;
		if (!ReadFstab(fstab_file, &fstab) \|\| fstab.empty()) {
		PLOG(ERROR) << "Failed to read fstab";
		return NO_FSTAB;
		@@ -254,60 +332,13 @@ static int do_remount(int argc, char* argv[]) {
		return rv;
		}

		// Generate the list of supported overlayfs mount points.
		auto overlayfs_candidates = fs_mgr_overlayfs_candidate_list(fstab);

		// Generate the all remountable partitions sub-list
		android::fs_mgr::Fstab all;
		for (auto const& entry : fstab) {
		if (!remountable_partition(entry)) continue;
		if (overlayfs_candidates.empty() \|\|
		GetEntryForMountPoint(&overlayfs_candidates, entry.mount_point) \|\|
		(is_wrapped(overlayfs_candidates, entry) == nullptr)) {
		all.emplace_back(entry);
		}
		}

		// Parse the unique list of valid partition arguments.
		android::fs_mgr::Fstab partitions;
		for (; argc > optind; ++optind) {
		auto partition = std::string(argv[optind]);
		if (partition.empty()) continue;
		if (partition == "/") partition = "/system";
		auto find_part = [&partition](const auto& entry) {
		const auto mount_point = system_mount_point(entry);
		if (partition == mount_point) return true;
		if (partition == android::base::Basename(mount_point)) return true;
		return false;
		};
		// Do we know about the partition?
		auto it = std::find_if(fstab.begin(), fstab.end(), find_part);
		if (it == fstab.end()) {
		LOG(ERROR) << "Unknown partition " << argv[optind] << ", skipping";
		retval = UNKNOWN_PARTITION;
		continue;
		}
		// Is that one covered by an existing overlayfs?
		auto wrap = is_wrapped(overlayfs_candidates, *it);
		if (wrap) {
		LOG(INFO) << "partition " << argv[optind] << " covered by overlayfs for "
		<< wrap->mount_point << ", switching";
		partition = system_mount_point(*wrap);
		}
		// Is it a remountable partition?
		it = std::find_if(all.begin(), all.end(), find_part);
		if (it == all.end()) {
		LOG(ERROR) << "Invalid partition " << argv[optind] << ", skipping";
		retval = INVALID_PARTITION;
		continue;
		}
		if (GetEntryForMountPoint(&partitions, it->mount_point) == nullptr) {
		partitions.emplace_back(*it);
		}
		Fstab partitions;
		if (partition_args.empty()) {
		partitions = GetAllRemountablePartitions(fstab);
		} else {
		if (auto rv = GetRemountList(fstab, partition_args, &partitions); rv != REMOUNT_SUCCESS) {
		return rv;
		}

		if (partitions.empty() && !retval) {
		partitions = all;
		}

		// Check verity and optionally setup overlayfs backing.