Merge "liblp: Add a helper to differentiate empty from non-empty images." (878930be) · Commits · e / os / android_system_core

fs_mgr/liblp/images.cpp

+34 −0

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@
		#include "images.h"

		#include <limits.h>
		#include <sys/stat.h>

		#include <android-base/file.h>

		@@ -27,12 +28,45 @@
		namespace android {
		namespace fs_mgr {

		using android::base::borrowed_fd;
		using android::base::unique_fd;

		#if defined(_WIN32)
		static const int O_NOFOLLOW = 0;
		#endif

		static bool IsEmptySuperImage(borrowed_fd fd) {
		struct stat s;
		if (fstat(fd.get(), &s) < 0) {
		PERROR << __PRETTY_FUNCTION__ << " fstat failed";
		return false;
		}
		if (s.st_size < LP_METADATA_GEOMETRY_SIZE) {
		return false;
		}

		// Rewind back to the start, read the geometry struct.
		LpMetadataGeometry geometry = {};
		if (SeekFile64(fd.get(), 0, SEEK_SET) < 0) {
		PERROR << __PRETTY_FUNCTION__ << " lseek failed";
		return false;
		}
		if (!android::base::ReadFully(fd, &geometry, sizeof(geometry))) {
		PERROR << __PRETTY_FUNCTION__ << " read failed";
		return false;
		}
		return geometry.magic == LP_METADATA_GEOMETRY_MAGIC;
		}

		bool IsEmptySuperImage(const std::string& file) {
		unique_fd fd = GetControlFileOrOpen(file, O_RDONLY \| O_CLOEXEC);
		if (fd < 0) {
		PERROR << __PRETTY_FUNCTION__ << " open failed";
		return false;
		}
		return IsEmptySuperImage(fd);
		}

		std::unique_ptr<LpMetadata> ReadFromImageFile(int fd) {
		std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(LP_METADATA_GEOMETRY_SIZE);
		if (SeekFile64(fd, 0, SEEK_SET) < 0) {

+8 −1

Original line number	Diff line number	Diff line
		@@ -70,8 +70,15 @@ bool UpdatePartitionTable(const std::string& super_partition, const LpMetadata&
		uint32_t slot_number);
		std::unique_ptr<LpMetadata> ReadMetadata(const std::string& super_partition, uint32_t slot_number);

		// Returns whether an image is an "empty" image or not. An empty image contains
		// only metadata. Unlike a flashed block device, there are no reserved bytes or
		// backup sections, and only one slot is stored (even if multiple slots are
		// supported). It is a format specifically for storing only metadata.
		bool IsEmptySuperImage(const std::string& file);

		// Read/Write logical partition metadata to an image file, for diagnostics or
		// flashing.
		// flashing. If no partition images are specified, the file will be in the
		// empty format.
		bool WriteToImageFile(const std::string& file, const LpMetadata& metadata, uint32_t block_size,
		const std::map<std::string, std::string>& images, bool sparsify);
		bool WriteToImageFile(const std::string& file, const LpMetadata& metadata);

+3 −3

Original line number	Diff line number	Diff line
		@@ -205,9 +205,9 @@ bool SetBlockReadonly(int fd, bool readonly) {
		#endif
		}

		base::unique_fd GetControlFileOrOpen(const char* path, int flags) {
		base::unique_fd GetControlFileOrOpen(std::string_view path, int flags) {
		#if defined(__ANDROID__)
		int fd = android_get_control_file(path);
		int fd = android_get_control_file(path.data());
		if (fd >= 0) {
		int newfd = TEMP_FAILURE_RETRY(dup(fd));
		if (newfd >= 0) {
		@@ -216,7 +216,7 @@ base::unique_fd GetControlFileOrOpen(const char* path, int flags) {
		PERROR << "Cannot dup fd for already controlled file: " << path << ", reopening...";
		}
		#endif
		return base::unique_fd(open(path, flags));
		return base::unique_fd(open(path.data(), flags));
		}

		bool UpdateMetadataForInPlaceSnapshot(LpMetadata* metadata, uint32_t source_slot_number,

+4 −1

Original line number	Diff line number	Diff line
		@@ -21,6 +21,9 @@
		#include <stdint.h>
		#include <sys/types.h>

		#include <string>
		#include <string_view>

		#include <android-base/logging.h>
		#include <android-base/unique_fd.h>

		@@ -94,7 +97,7 @@ bool UpdatePartitionName(LpMetadataPartition* partition, const std::string& name
		// Call BLKROSET ioctl on fd so that fd is readonly / read-writable.
		bool SetBlockReadonly(int fd, bool readonly);

		::android::base::unique_fd GetControlFileOrOpen(const char* path, int flags);
		::android::base::unique_fd GetControlFileOrOpen(std::string_view path, int flags);

		// For Virtual A/B updates, modify \|metadata\| so that it can be written to \|target_slot_number\|.
		bool UpdateMetadataForInPlaceSnapshot(LpMetadata* metadata, uint32_t source_slot_number,