Merge "Allow mapping of raw block devices to partition names" (18a9324e) · Commits · e / os / android_system_core

init/block_dev_initializer.cpp

+7 −1

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

		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()) {
		return ListenerAction::kContinue;
		}
		}

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

init/devices.cpp

+35 −0

Original line number	Diff line number	Diff line
		@@ -46,6 +46,7 @@ using android::base::Dirname;
		using android::base::ReadFileToString;
		using android::base::Readlink;
		using android::base::Realpath;
		using android::base::Split;
		using android::base::StartsWith;
		using android::base::StringPrintf;
		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
		// parent directory with a 'subsystem' symlink that points to the platform bus.
		// 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
		// symlink of /dev/block/by-name/<device_name> for symmetry.
		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('/');

init/devices.h

+6 −0

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

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