Merge "Improved libdm and dmctl to handle very large numbers of extents" (083797ad) · Commits · e / os / android_system_core

fs_mgr/libdm/dm.cpp

+18 −17

Original line number	Diff line number	Diff line
		@@ -299,24 +299,25 @@ bool DeviceMapper::GetTableInfo(const std::string& name, std::vector<TargetInfo>
		// private methods of DeviceMapper
		bool DeviceMapper::GetTable(const std::string& name, uint32_t flags,
		std::vector<TargetInfo>* table) {
		char buffer[4096];
		struct dm_ioctl* io = reinterpret_cast<struct dm_ioctl*>(buffer);
		std::vector<char> buffer;
		struct dm_ioctl* io = nullptr;

		for (buffer.resize(4096);; buffer.resize(buffer.size() * 2)) {
		io = reinterpret_cast<struct dm_ioctl*>(&buffer[0]);

		InitIo(io, name);
		io->data_size = sizeof(buffer);
		io->data_size = buffer.size();
		io->data_start = sizeof(*io);
		io->flags = flags;
		if (ioctl(fd_, DM_TABLE_STATUS, io) < 0) {
		PLOG(ERROR) << "DM_TABLE_STATUS failed for " << name;
		return false;
		}
		if (io->flags & DM_BUFFER_FULL_FLAG) {
		PLOG(ERROR) << "DM_TABLE_STATUS result for " << name << " was too large";
		return false;
		if (!(io->flags & DM_BUFFER_FULL_FLAG)) break;
		}

		uint32_t cursor = io->data_start;
		uint32_t data_end = std::min(io->data_size, uint32_t(sizeof(buffer)));
		uint32_t data_end = std::min(io->data_size, uint32_t(buffer.size()));
		for (uint32_t i = 0; i < io->target_count; i++) {
		if (cursor + sizeof(struct dm_target_spec) > data_end) {
		break;
		@@ -324,14 +325,14 @@ bool DeviceMapper::GetTable(const std::string& name, uint32_t flags,
		// After each dm_target_spec is a status string. spec->next is an
		// offset from \|io->data_start\|, and we clamp it to the size of our
		// buffer.
		struct dm_target_spec* spec = reinterpret_cast<struct dm_target_spec*>(buffer + cursor);
		struct dm_target_spec* spec = reinterpret_cast<struct dm_target_spec*>(&buffer[cursor]);
		uint32_t data_offset = cursor + sizeof(dm_target_spec);
		uint32_t next_cursor = std::min(io->data_start + spec->next, data_end);

		std::string data;
		if (next_cursor > data_offset) {
		// Note: we use c_str() to eliminate any extra trailing 0s.
		data = std::string(buffer + data_offset, next_cursor - data_offset).c_str();
		data = std::string(&buffer[data_offset], next_cursor - data_offset).c_str();
		}
		table->emplace_back(*spec, data);
		cursor = next_cursor;

fs_mgr/tools/dmctl.cpp

+32 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include <android-base/unique_fd.h>
		#include <libdm/dm.h>

		#include <fstream>
		#include <functional>
		#include <iomanip>
		#include <ios>
		@@ -50,6 +51,7 @@ using DmBlockDevice = ::android::dm::DeviceMapper::DmBlockDevice;

		static int Usage(void) {
		std::cerr << "usage: dmctl <command> [command options]" << std::endl;
		std::cerr << " dmctl -f file" << std::endl;
		std::cerr << "commands:" << std::endl;
		std::cerr << " create <dm-name> [-ro] <targets...>" << std::endl;
		std::cerr << " delete <dm-name>" << std::endl;
		@@ -58,6 +60,8 @@ static int Usage(void) {
		std::cerr << " table <dm-name>" << std::endl;
		std::cerr << " help" << std::endl;
		std::cerr << std::endl;
		std::cerr << "-f file reads command and all parameters from named file" << std::endl;
		std::cerr << std::endl;
		std::cerr << "Target syntax:" << std::endl;
		std::cerr << " <target_type> <start_sector> <num_sectors> [target_data]" << std::endl;
		return -EINVAL;
		@@ -340,12 +344,40 @@ static std::map<std::string, std::function<int(int, char**)>> cmdmap = {
		// clang-format on
		};

		static bool ReadFile(const char* filename, std::vector<std::string>* args,
		std::vector<char> arg_ptrs) {
		std::ifstream file(filename);
		if (!file) return false;

		std::string arg;
		while (file >> arg) args->push_back(arg);

		for (auto const& i : args) arg_ptrs->push_back(const_cast<char>(i.c_str()));
		return true;
		}

		int main(int argc, char** argv) {
		android::base::InitLogging(argv, &android::base::StderrLogger);
		if (argc < 2) {
		return Usage();
		}

		std::vector<std::string> args;
		std::vector<char*> arg_ptrs;
		if (std::string("-f") == argv[1]) {
		if (argc != 3) {
		return Usage();
		}

		args.push_back(argv[0]);
		if (!ReadFile(argv[2], &args, &arg_ptrs)) {
		return Usage();
		}

		argc = arg_ptrs.size();
		argv = &arg_ptrs[0];
		}

		for (const auto& cmd : cmdmap) {
		if (cmd.first == argv[1]) {
		return cmd.second(argc - 2, argv + 2);