Merge "Allow mapping of raw block devices to partition names" am: 18a9324e3f (43fede94) · Commits · e / os / android_system_core

init/block_dev_initializer.cpp

+7 −1

Original line number	Original line	Diff line number	Diff line
	@@ -86,9 +86,15 @@ ListenerAction BlockDevInitializer::HandleUevent(const Uevent& uevent,
	}		}

	auto iter = devices->find(name);		auto iter = devices->find(name);
			if (iter == devices->end()) {
			auto partition_name = DeviceHandler::GetPartitionNameForDevice(uevent.device_name);
			if (!partition_name.empty()) {
			iter = devices->find(partition_name);
			}
	if (iter == devices->end()) {		if (iter == devices->end()) {
	return ListenerAction::kContinue;		return ListenerAction::kContinue;
	}		}
			}

	LOG(VERBOSE) << __PRETTY_FUNCTION__ << ": found partition: " << name;		LOG(VERBOSE) << __PRETTY_FUNCTION__ << ": found partition: " << name;

init/devices.cpp

+35 −0

Original line number	Original line	Diff line number	Diff line
	@@ -46,6 +46,7 @@ using android::base::Dirname;
	using android::base::ReadFileToString;		using android::base::ReadFileToString;
	using android::base::Readlink;		using android::base::Readlink;
	using android::base::Realpath;		using android::base::Realpath;
			using android::base::Split;
	using android::base::StartsWith;		using android::base::StartsWith;
	using android::base::StringPrintf;		using android::base::StringPrintf;
	using android::base::Trim;		using android::base::Trim;
	@@ -187,6 +188,36 @@ void SysfsPermissions::SetPermissions(const std::string& path) const {
	}		}
	}		}

			std::string DeviceHandler::GetPartitionNameForDevice(const std::string& query_device) {
			static const auto partition_map = [] {
			std::vector<std::pair<std::string, std::string>> partition_map;
			auto parser = [&partition_map](const std::string& key, const std::string& value) {
			if (key != "androidboot.partition_map") {
			return;
			}
			for (const auto& map : Split(value, ";")) {
			auto map_pieces = Split(map, ",");
			if (map_pieces.size() != 2) {
			LOG(ERROR) << "Expected a comma separated device,partition mapping, but found '"
			<< map << "'";
			continue;
			}
			partition_map.emplace_back(map_pieces[0], map_pieces[1]);
			}
			};
			ImportKernelCmdline(parser);
			ImportBootconfig(parser);
			return partition_map;
			}();

			for (const auto& [device, partition] : partition_map) {
			if (query_device == device) {
			return partition;
			}
			}
			return {};
			}

	// Given a path that may start with a platform device, find the parent platform device by finding a		// Given a path that may start with a platform device, find the parent platform device by finding a
	// parent directory with a 'subsystem' symlink that points to the platform bus.		// parent directory with a 'subsystem' symlink that points to the platform bus.
	// If it doesn't start with a platform device, return false		// If it doesn't start with a platform device, return false
	@@ -389,6 +420,10 @@ std::vector<std::string> DeviceHandler::GetBlockDeviceSymlinks(const Uevent& uev
	// If we don't have a partition name but we are a partition on a boot device, create a		// If we don't have a partition name but we are a partition on a boot device, create a
	// symlink of /dev/block/by-name/<device_name> for symmetry.		// symlink of /dev/block/by-name/<device_name> for symmetry.
	links.emplace_back("/dev/block/by-name/" + uevent.device_name);		links.emplace_back("/dev/block/by-name/" + uevent.device_name);
			auto partition_name = GetPartitionNameForDevice(uevent.device_name);
			if (!partition_name.empty()) {
			links.emplace_back("/dev/block/by-name/" + partition_name);
			}
	}		}

	auto last_slash = uevent.path.rfind('/');		auto last_slash = uevent.path.rfind('/');

init/devices.h

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -122,6 +122,12 @@ class DeviceHandler : public UeventHandler {

	std::vector<std::string> GetBlockDeviceSymlinks(const Uevent& uevent) const;		std::vector<std::string> GetBlockDeviceSymlinks(const Uevent& uevent) const;

			// `androidboot.partition_map` allows associating a partition name for a raw block device
			// through a comma separated and semicolon deliminated list. For example,
			// `androidboot.partition_map=vdb,metadata;vdc,userdata` maps `vdb` to `metadata` and `vdc` to
			// `userdata`.
			static std::string GetPartitionNameForDevice(const std::string& device);

	private:		private:
	bool FindPlatformDevice(std::string path, std::string* platform_device_path) const;		bool FindPlatformDevice(std::string path, std::string* platform_device_path) const;
	std::tuple<mode_t, uid_t, gid_t> GetDevicePermissions(		std::tuple<mode_t, uid_t, gid_t> GetDevicePermissions(