remount: Refactor remounting into a helper function. (584fe256) · Commits · e / os / android_system_core

fs_mgr/fs_mgr_remount.cpp

+63 −67

Original line number	Diff line number	Diff line
		@@ -364,9 +364,65 @@ static RemountStatus EnableDsuIfNeeded() {
		return REMOUNT_SUCCESS;
		}

		static int do_remount(int argc, char* argv[]) {
		RemountStatus retval = REMOUNT_SUCCESS;
		static RemountStatus RemountPartition(Fstab& fstab, Fstab& mounts, FstabEntry& entry) {
		// unlock the r/o key for the mount point device
		if (entry.fs_mgr_flags.logical) {
		fs_mgr_update_logical_partition(&entry);
		}
		auto blk_device = entry.blk_device;
		auto mount_point = entry.mount_point;

		auto found = false;
		for (auto it = mounts.rbegin(); it != mounts.rend(); ++it) {
		auto& rentry = *it;
		if (mount_point == rentry.mount_point) {
		blk_device = rentry.blk_device;
		found = true;
		break;
		}
		// Find overlayfs mount point?
		if ((mount_point == "/" && rentry.mount_point == "/system") \|\|
		(mount_point == "/system" && rentry.mount_point == "/")) {
		blk_device = rentry.blk_device;
		mount_point = "/system";
		found = true;
		break;
		}
		}
		if (!found) {
		PLOG(INFO) << "skip unmounted partition dev:" << blk_device << " mnt:" << mount_point;
		return REMOUNT_SUCCESS;
		}
		if (blk_device == "/dev/root") {
		auto from_fstab = GetEntryForMountPoint(&fstab, mount_point);
		if (from_fstab) blk_device = from_fstab->blk_device;
		}
		fs_mgr_set_blk_ro(blk_device, false);

		// Find system-as-root mount point?
		if ((mount_point == "/system") && !GetEntryForMountPoint(&mounts, mount_point) &&
		GetEntryForMountPoint(&mounts, "/")) {
		mount_point = "/";
		}

		// Now remount!
		if (::mount(blk_device.c_str(), mount_point.c_str(), entry.fs_type.c_str(), MS_REMOUNT,
		nullptr) == 0) {
		return REMOUNT_SUCCESS;
		}
		if ((errno == EINVAL) && (mount_point != entry.mount_point)) {
		mount_point = entry.mount_point;
		if (::mount(blk_device.c_str(), mount_point.c_str(), entry.fs_type.c_str(), MS_REMOUNT,
		nullptr) == 0) {
		return REMOUNT_SUCCESS;
		}
		}

		PLOG(ERROR) << "failed to remount partition dev:" << blk_device << " mnt:" << mount_point;
		return REMOUNT_FAILED;
		}

		static int do_remount(int argc, char* argv[]) {
		// If somehow this executable is delivered on a "user" build, it can
		// not function, so providing a clear message to the caller rather than
		// letting if fall through and provide a lot of confusing failure messages.
		@@ -446,7 +502,7 @@ static int do_remount(int argc, char* argv[]) {

		// Check verity and optionally setup overlayfs backing.
		RemountCheckResult check_result;
		retval = CheckVerityAndOverlayfs(&partitions, &check_result);
		auto retval = CheckVerityAndOverlayfs(&partitions, &check_result);

		bool auto_reboot = check_result.reboot_later && can_reboot;

		@@ -474,88 +530,28 @@ static int do_remount(int argc, char* argv[]) {
		// Mount overlayfs.
		errno = 0;
		if (!fs_mgr_overlayfs_mount_all(&partitions) && errno) {
		retval = BAD_OVERLAY;
		PLOG(ERROR) << "Can not mount overlayfs for partitions";
		return BAD_OVERLAY;
		}

		// Get actual mounts _after_ overlayfs has been added.
		android::fs_mgr::Fstab mounts;
		if (!android::fs_mgr::ReadFstabFromFile("/proc/mounts", &mounts) \|\| mounts.empty()) {
		PLOG(ERROR) << "Failed to read /proc/mounts";
		retval = NO_MOUNTS;
		return NO_MOUNTS;
		}

		// Remount selected partitions.
		for (auto& entry : partitions) {
		// unlock the r/o key for the mount point device
		if (entry.fs_mgr_flags.logical) {
		fs_mgr_update_logical_partition(&entry);
		}
		auto blk_device = entry.blk_device;
		auto mount_point = entry.mount_point;

		auto found = false;
		for (auto it = mounts.rbegin(); it != mounts.rend(); ++it) {
		auto& rentry = *it;
		if (mount_point == rentry.mount_point) {
		blk_device = rentry.blk_device;
		found = true;
		break;
		}
		// Find overlayfs mount point?
		if ((mount_point == "/" && rentry.mount_point == "/system") \|\|
		(mount_point == "/system" && rentry.mount_point == "/")) {
		blk_device = rentry.blk_device;
		mount_point = "/system";
		found = true;
		break;
		}
		}
		if (!found) {
		PLOG(INFO) << "skip unmounted partition dev:" << blk_device << " mnt:" << mount_point;
		continue;
		if (auto rv = RemountPartition(fstab, mounts, entry); rv != REMOUNT_SUCCESS) {
		retval = rv;
		}
		if (blk_device == "/dev/root") {
		auto from_fstab = GetEntryForMountPoint(&fstab, mount_point);
		if (from_fstab) blk_device = from_fstab->blk_device;
		}
		fs_mgr_set_blk_ro(blk_device, false);

		// Find system-as-root mount point?
		if ((mount_point == "/system") && !GetEntryForMountPoint(&mounts, mount_point) &&
		GetEntryForMountPoint(&mounts, "/")) {
		mount_point = "/";
		}

		// Now remount!
		if (::mount(blk_device.c_str(), mount_point.c_str(), entry.fs_type.c_str(), MS_REMOUNT,
		nullptr) == 0) {
		continue;
		}
		if ((errno == EINVAL) && (mount_point != entry.mount_point)) {
		mount_point = entry.mount_point;
		if (::mount(blk_device.c_str(), mount_point.c_str(), entry.fs_type.c_str(), MS_REMOUNT,
		nullptr) == 0) {
		continue;
		}
		}
		PLOG(ERROR) << "failed to remount partition dev:" << blk_device << " mnt:" << mount_point;
		// If errno is EROFS at this point, we are dealing with r/o
		// filesystem types like squashfs, erofs or ext4 dedupe. We will
		// consider such a device that does not have CONFIG_OVERLAY_FS
		// in the kernel as a misconfigured.
		if (errno == EROFS) {
		LOG(ERROR) << "Consider providing all the dependencies to enable overlayfs";
		}
		retval = REMOUNT_FAILED;
		}

		if (auto_reboot) reboot(check_result.setup_overlayfs);
		if (check_result.reboot_later) {
		LOG(INFO) << "Now reboot your device for settings to take effect";
		return 0;
		}

		return retval;
		}