| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "first_stage_init.h" |
| |
| #include <dirent.h> |
| #include <fcntl.h> |
| #include <paths.h> |
| #include <stdlib.h> |
| #include <sys/mount.h> |
| #include <sys/stat.h> |
| #include <sys/sysmacros.h> |
| #include <sys/types.h> |
| #include <sys/utsname.h> |
| #include <unistd.h> |
| |
| #include <chrono> |
| #include <filesystem> |
| #include <string> |
| #include <vector> |
| |
| #include <android-base/chrono_utils.h> |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/stringprintf.h> |
| #include <modprobe/modprobe.h> |
| #include <private/android_filesystem_config.h> |
| |
| #include "debug_ramdisk.h" |
| #include "first_stage_console.h" |
| #include "first_stage_mount.h" |
| #include "reboot_utils.h" |
| #include "second_stage_resources.h" |
| #include "snapuserd_transition.h" |
| #include "switch_root.h" |
| #include "util.h" |
| |
| using android::base::boot_clock; |
| |
| using namespace std::literals; |
| |
| namespace fs = std::filesystem; |
| |
| namespace android { |
| namespace init { |
| |
| namespace { |
| |
| enum class BootMode { |
| NORMAL_MODE, |
| RECOVERY_MODE, |
| CHARGER_MODE, |
| }; |
| |
| void FreeRamdisk(DIR* dir, dev_t dev) { |
| int dfd = dirfd(dir); |
| |
| dirent* de = nullptr; |
| while ((de = readdir(dir)) != nullptr) { |
| if (de->d_name == "."s || de->d_name == ".."s) { |
| continue; |
| } |
| |
| bool is_dir = false; |
| |
| if (de->d_type == DT_DIR || de->d_type == DT_UNKNOWN) { |
| struct stat info {}; |
| if (fstatat(dfd, de->d_name, &info, AT_SYMLINK_NOFOLLOW) != 0) { |
| continue; |
| } |
| |
| if (info.st_dev != dev) { |
| continue; |
| } |
| |
| if (S_ISDIR(info.st_mode)) { |
| is_dir = true; |
| auto fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY | O_CLOEXEC); |
| if (fd >= 0) { |
| auto subdir = |
| std::unique_ptr<DIR, decltype(&closedir)>{fdopendir(fd), closedir}; |
| if (subdir) { |
| FreeRamdisk(subdir.get(), dev); |
| } else { |
| close(fd); |
| } |
| } |
| } |
| } else if (de->d_type == DT_REG) { |
| // Do not free snapuserd if we will need the ramdisk copy during the |
| // selinux transition. |
| if (de->d_name == "snapuserd"s && IsFirstStageSnapuserdRunning()) { |
| continue; |
| } |
| } |
| unlinkat(dfd, de->d_name, is_dir ? AT_REMOVEDIR : 0); |
| } |
| } |
| |
| bool ForceNormalBoot(const std::string& cmdline, const std::string& bootconfig) { |
| return bootconfig.find("androidboot.force_normal_boot = \"1\"") != std::string::npos || |
| cmdline.find("androidboot.force_normal_boot=1") != std::string::npos; |
| } |
| |
| static void Copy(const char* src, const char* dst) { |
| if (link(src, dst) == 0) { |
| LOG(INFO) << "hard linking " << src << " to " << dst << " succeeded"; |
| return; |
| } |
| PLOG(FATAL) << "hard linking " << src << " to " << dst << " failed"; |
| } |
| |
| // Move snapuserd before switching root, so that it is available at the same path |
| // after switching root. |
| void PrepareSwitchRoot() { |
| static constexpr const auto& snapuserd = "/system/bin/snapuserd"; |
| static constexpr const auto& snapuserd_ramdisk = "/system/bin/snapuserd_ramdisk"; |
| static constexpr const auto& dst = "/first_stage_ramdisk/system/bin/snapuserd"; |
| |
| if (access(dst, X_OK) == 0) { |
| LOG(INFO) << dst << " already exists and it can be executed"; |
| return; |
| } |
| auto dst_dir = android::base::Dirname(dst); |
| std::error_code ec; |
| if (access(dst_dir.c_str(), F_OK) != 0) { |
| if (!fs::create_directories(dst_dir, ec)) { |
| LOG(FATAL) << "Cannot create " << dst_dir << ": " << ec.message(); |
| } |
| } |
| |
| // prefer the generic ramdisk copy of snapuserd, because that's on system side of treble |
| // boundary, and therefore is more likely to be updated along with the Android platform. |
| // The vendor ramdisk copy might be under vendor freeze, or vendor might choose not to update |
| // it. |
| if (access(snapuserd_ramdisk, F_OK) == 0) { |
| LOG(INFO) << "Using generic ramdisk copy of snapuserd " << snapuserd_ramdisk; |
| Copy(snapuserd_ramdisk, dst); |
| } else if (access(snapuserd, F_OK) == 0) { |
| LOG(INFO) << "Using vendor ramdisk copy of snapuserd " << snapuserd; |
| Copy(snapuserd, dst); |
| } |
| } |
| |
| std::string GetPageSizeSuffix() { |
| static const size_t page_size = sysconf(_SC_PAGE_SIZE); |
| if (page_size <= 4096) { |
| return ""; |
| } |
| return android::base::StringPrintf("_%zuk", page_size / 1024); |
| } |
| |
| constexpr bool EndsWith(const std::string_view str, const std::string_view suffix) { |
| return str.size() >= suffix.size() && |
| 0 == str.compare(str.size() - suffix.size(), suffix.size(), suffix); |
| } |
| |
| constexpr std::string_view GetPageSizeSuffix(std::string_view dirname) { |
| if (EndsWith(dirname, "_16k")) { |
| return "_16k"; |
| } |
| if (EndsWith(dirname, "_64k")) { |
| return "_64k"; |
| } |
| return ""; |
| } |
| |
| } // namespace |
| |
| std::string GetModuleLoadList(BootMode boot_mode, const std::string& dir_path) { |
| std::string module_load_file; |
| |
| switch (boot_mode) { |
| case BootMode::NORMAL_MODE: |
| module_load_file = "modules.load"; |
| break; |
| case BootMode::RECOVERY_MODE: |
| module_load_file = "modules.load.recovery"; |
| break; |
| case BootMode::CHARGER_MODE: |
| module_load_file = "modules.load.charger"; |
| break; |
| } |
| |
| if (module_load_file != "modules.load") { |
| struct stat fileStat {}; |
| std::string load_path = dir_path + "/" + module_load_file; |
| // Fall back to modules.load if the other files aren't accessible |
| if (stat(load_path.c_str(), &fileStat)) { |
| module_load_file = "modules.load"; |
| } |
| } |
| |
| return module_load_file; |
| } |
| |
| #define MODULE_BASE_DIR "/lib/modules" |
| bool LoadKernelModules(BootMode boot_mode, bool want_console, bool want_parallel, |
| int& modules_loaded) { |
| struct utsname uts {}; |
| if (uname(&uts)) { |
| LOG(FATAL) << "Failed to get kernel version."; |
| } |
| int major = 0, minor = 0; |
| if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) { |
| LOG(FATAL) << "Failed to parse kernel version " << uts.release; |
| } |
| |
| std::unique_ptr<DIR, decltype(&closedir)> base_dir(opendir(MODULE_BASE_DIR), closedir); |
| if (!base_dir) { |
| LOG(INFO) << "Unable to open /lib/modules, skipping module loading."; |
| return true; |
| } |
| dirent* entry = nullptr; |
| std::vector<std::string> module_dirs; |
| const auto page_size_suffix = GetPageSizeSuffix(); |
| const std::string release_specific_module_dir = uts.release + page_size_suffix; |
| while ((entry = readdir(base_dir.get()))) { |
| if (entry->d_type != DT_DIR) { |
| continue; |
| } |
| if (entry->d_name == release_specific_module_dir) { |
| LOG(INFO) << "Release specific kernel module dir " << release_specific_module_dir |
| << " found, loading modules from here with no fallbacks."; |
| module_dirs.clear(); |
| module_dirs.emplace_back(entry->d_name); |
| break; |
| } |
| // Ignore _16k/_64k module dirs on 4K kernels |
| if (GetPageSizeSuffix(entry->d_name) != page_size_suffix) { |
| continue; |
| } |
| int dir_major = 0, dir_minor = 0; |
| if (sscanf(entry->d_name, "%d.%d", &dir_major, &dir_minor) != 2 || dir_major != major || |
| dir_minor != minor) { |
| continue; |
| } |
| module_dirs.emplace_back(entry->d_name); |
| } |
| |
| // Sort the directories so they are iterated over during module loading |
| // in a consistent order. Alphabetical sorting is fine here because the |
| // kernel version at the beginning of the directory name must match the |
| // current kernel version, so the sort only applies to a label that |
| // follows the kernel version, for example /lib/modules/5.4 vs. |
| // /lib/modules/5.4-gki. |
| std::sort(module_dirs.begin(), module_dirs.end()); |
| |
| for (const auto& module_dir : module_dirs) { |
| std::string dir_path = MODULE_BASE_DIR "/"; |
| dir_path.append(module_dir); |
| Modprobe m({dir_path}, GetModuleLoadList(boot_mode, dir_path)); |
| bool retval = m.LoadListedModules(!want_console); |
| modules_loaded = m.GetModuleCount(); |
| if (modules_loaded > 0) { |
| LOG(INFO) << "Loaded " << modules_loaded << " modules from " << dir_path; |
| return retval; |
| } |
| } |
| |
| Modprobe m({MODULE_BASE_DIR}, GetModuleLoadList(boot_mode, MODULE_BASE_DIR)); |
| bool retval = (want_parallel) ? m.LoadModulesParallel(std::thread::hardware_concurrency()) |
| : m.LoadListedModules(!want_console); |
| modules_loaded = m.GetModuleCount(); |
| if (modules_loaded > 0) { |
| LOG(INFO) << "Loaded " << modules_loaded << " modules from " << MODULE_BASE_DIR; |
| return retval; |
| } |
| return true; |
| } |
| |
| static bool IsChargerMode(const std::string& cmdline, const std::string& bootconfig) { |
| return bootconfig.find("androidboot.mode = \"charger\"") != std::string::npos || |
| cmdline.find("androidboot.mode=charger") != std::string::npos; |
| } |
| |
| static BootMode GetBootMode(const std::string& cmdline, const std::string& bootconfig) |
| { |
| if (IsChargerMode(cmdline, bootconfig)) |
| return BootMode::CHARGER_MODE; |
| else if (IsRecoveryMode() && !ForceNormalBoot(cmdline, bootconfig)) |
| return BootMode::RECOVERY_MODE; |
| |
| return BootMode::NORMAL_MODE; |
| } |
| |
| static std::unique_ptr<FirstStageMount> CreateFirstStageMount(const std::string& cmdline) { |
| auto ret = FirstStageMount::Create(cmdline); |
| if (ret.ok()) { |
| return std::move(*ret); |
| } else { |
| LOG(ERROR) << "Failed to create FirstStageMount : " << ret.error(); |
| return nullptr; |
| } |
| } |
| |
| int FirstStageMain(int argc, char** argv) { |
| if (REBOOT_BOOTLOADER_ON_PANIC) { |
| InstallRebootSignalHandlers(); |
| } |
| |
| boot_clock::time_point start_time = boot_clock::now(); |
| |
| std::vector<std::pair<std::string, int>> errors; |
| #define CHECKCALL(x) \ |
| if ((x) != 0) errors.emplace_back(#x " failed", errno); |
| |
| // Clear the umask. |
| umask(0); |
| |
| CHECKCALL(clearenv()); |
| CHECKCALL(setenv("PATH", _PATH_DEFPATH, 1)); |
| // Get the basic filesystem setup we need put together in the initramdisk |
| // on / and then we'll let the rc file figure out the rest. |
| CHECKCALL(mount("tmpfs", "/dev", "tmpfs", MS_NOSUID, "mode=0755")); |
| CHECKCALL(mkdir("/dev/pts", 0755)); |
| CHECKCALL(mkdir("/dev/socket", 0755)); |
| CHECKCALL(mkdir("/dev/dm-user", 0755)); |
| CHECKCALL(mount("devpts", "/dev/pts", "devpts", 0, NULL)); |
| #define MAKE_STR(x) __STRING(x) |
| CHECKCALL(mount("proc", "/proc", "proc", 0, "hidepid=2,gid=" MAKE_STR(AID_READPROC))); |
| #undef MAKE_STR |
| // Don't expose the raw commandline to unprivileged processes. |
| CHECKCALL(chmod("/proc/cmdline", 0440)); |
| std::string cmdline; |
| android::base::ReadFileToString("/proc/cmdline", &cmdline); |
| // Don't expose the raw bootconfig to unprivileged processes. |
| chmod("/proc/bootconfig", 0440); |
| std::string bootconfig; |
| android::base::ReadFileToString("/proc/bootconfig", &bootconfig); |
| gid_t groups[] = {AID_READPROC}; |
| CHECKCALL(setgroups(arraysize(groups), groups)); |
| CHECKCALL(mount("sysfs", "/sys", "sysfs", 0, NULL)); |
| CHECKCALL(mount("selinuxfs", "/sys/fs/selinux", "selinuxfs", 0, NULL)); |
| |
| CHECKCALL(mknod("/dev/kmsg", S_IFCHR | 0600, makedev(1, 11))); |
| |
| if constexpr (WORLD_WRITABLE_KMSG) { |
| CHECKCALL(mknod("/dev/kmsg_debug", S_IFCHR | 0622, makedev(1, 11))); |
| } |
| |
| CHECKCALL(mknod("/dev/random", S_IFCHR | 0666, makedev(1, 8))); |
| CHECKCALL(mknod("/dev/urandom", S_IFCHR | 0666, makedev(1, 9))); |
| |
| // This is needed for log wrapper, which gets called before ueventd runs. |
| CHECKCALL(mknod("/dev/ptmx", S_IFCHR | 0666, makedev(5, 2))); |
| CHECKCALL(mknod("/dev/null", S_IFCHR | 0666, makedev(1, 3))); |
| |
| // These below mounts are done in first stage init so that first stage mount can mount |
| // subdirectories of /mnt/{vendor,product}/. Other mounts, not required by first stage mount, |
| // should be done in rc files. |
| // Mount staging areas for devices managed by vold |
| // See storage config details at http://source.android.com/devices/storage/ |
| CHECKCALL(mount("tmpfs", "/mnt", "tmpfs", MS_NOEXEC | MS_NOSUID | MS_NODEV, |
| "mode=0755,uid=0,gid=1000")); |
| // /mnt/vendor is used to mount vendor-specific partitions that can not be |
| // part of the vendor partition, e.g. because they are mounted read-write. |
| CHECKCALL(mkdir("/mnt/vendor", 0755)); |
| // /mnt/product is used to mount product-specific partitions that can not be |
| // part of the product partition, e.g. because they are mounted read-write. |
| CHECKCALL(mkdir("/mnt/product", 0755)); |
| |
| // /debug_ramdisk is used to preserve additional files from the debug ramdisk |
| CHECKCALL(mount("tmpfs", "/debug_ramdisk", "tmpfs", MS_NOEXEC | MS_NOSUID | MS_NODEV, |
| "mode=0755,uid=0,gid=0")); |
| |
| // /second_stage_resources is used to preserve files from first to second |
| // stage init |
| CHECKCALL(mount("tmpfs", kSecondStageRes, "tmpfs", MS_NOEXEC | MS_NOSUID | MS_NODEV, |
| "mode=0755,uid=0,gid=0")) |
| #undef CHECKCALL |
| |
| SetStdioToDevNull(argv); |
| // Now that tmpfs is mounted on /dev and we have /dev/kmsg, we can actually |
| // talk to the outside world... |
| InitKernelLogging(argv); |
| |
| if (!errors.empty()) { |
| for (const auto& [error_string, error_errno] : errors) { |
| LOG(ERROR) << error_string << " " << strerror(error_errno); |
| } |
| LOG(FATAL) << "Init encountered errors starting first stage, aborting"; |
| } |
| |
| LOG(INFO) << "init first stage started!"; |
| |
| // We only allow /vendor partition in debuggable Microdrod until it is verified during boot. |
| // TODO(b/285855436): remove this check. |
| if (IsMicrodroid()) { |
| bool mount_vendor = |
| cmdline.find("androidboot.microdroid.mount_vendor=1") != std::string::npos; |
| bool debuggable = |
| bootconfig.find("androidboot.microdroid.debuggable = \"1\"") != std::string::npos; |
| if (mount_vendor && !debuggable) { |
| LOG(FATAL) << "Attempted to mount /vendor partition for non-debuggable Microdroid VM"; |
| } |
| } |
| |
| auto old_root_dir = std::unique_ptr<DIR, decltype(&closedir)>{opendir("/"), closedir}; |
| if (!old_root_dir) { |
| PLOG(ERROR) << "Could not opendir(\"/\"), not freeing ramdisk"; |
| } |
| |
| struct stat old_root_info {}; |
| if (stat("/", &old_root_info) != 0) { |
| PLOG(ERROR) << "Could not stat(\"/\"), not freeing ramdisk"; |
| old_root_dir.reset(); |
| } |
| |
| auto want_console = ALLOW_FIRST_STAGE_CONSOLE ? FirstStageConsole(cmdline, bootconfig) : 0; |
| auto want_parallel = |
| bootconfig.find("androidboot.load_modules_parallel = \"true\"") != std::string::npos; |
| |
| boot_clock::time_point module_start_time = boot_clock::now(); |
| int module_count = 0; |
| BootMode boot_mode = GetBootMode(cmdline, bootconfig); |
| if (!LoadKernelModules(boot_mode, want_console, |
| want_parallel, module_count)) { |
| if (want_console != FirstStageConsoleParam::DISABLED) { |
| LOG(ERROR) << "Failed to load kernel modules, starting console"; |
| } else { |
| LOG(FATAL) << "Failed to load kernel modules"; |
| } |
| } |
| if (module_count > 0) { |
| auto module_elapse_time = std::chrono::duration_cast<std::chrono::milliseconds>( |
| boot_clock::now() - module_start_time); |
| setenv(kEnvInitModuleDurationMs, std::to_string(module_elapse_time.count()).c_str(), 1); |
| LOG(INFO) << "Loaded " << module_count << " kernel modules took " |
| << module_elapse_time.count() << " ms"; |
| } |
| |
| std::unique_ptr<FirstStageMount> fsm; |
| |
| bool created_devices = false; |
| if (want_console == FirstStageConsoleParam::CONSOLE_ON_FAILURE) { |
| if (!IsRecoveryMode()) { |
| fsm = CreateFirstStageMount(cmdline); |
| if (fsm) { |
| created_devices = fsm->DoCreateDevices(); |
| if (!created_devices) { |
| LOG(ERROR) << "Failed to create device nodes early"; |
| } |
| } |
| } |
| StartConsole(cmdline); |
| } |
| |
| if (access(kBootImageRamdiskProp, F_OK) == 0) { |
| std::string dest = GetRamdiskPropForSecondStage(); |
| std::string dir = android::base::Dirname(dest); |
| std::error_code ec; |
| if (!fs::create_directories(dir, ec) && !!ec) { |
| LOG(FATAL) << "Can't mkdir " << dir << ": " << ec.message(); |
| } |
| if (!fs::copy_file(kBootImageRamdiskProp, dest, ec)) { |
| LOG(FATAL) << "Can't copy " << kBootImageRamdiskProp << " to " << dest << ": " |
| << ec.message(); |
| } |
| LOG(INFO) << "Copied ramdisk prop to " << dest; |
| } |
| |
| // If "/force_debuggable" is present, the second-stage init will use a userdebug |
| // sepolicy and load adb_debug.prop to allow adb root, if the device is unlocked. |
| if (access("/force_debuggable", F_OK) == 0) { |
| constexpr const char adb_debug_prop_src[] = "/adb_debug.prop"; |
| constexpr const char userdebug_plat_sepolicy_cil_src[] = "/userdebug_plat_sepolicy.cil"; |
| std::error_code ec; // to invoke the overloaded copy_file() that won't throw. |
| if (access(adb_debug_prop_src, F_OK) == 0 && |
| !fs::copy_file(adb_debug_prop_src, kDebugRamdiskProp, ec)) { |
| LOG(WARNING) << "Can't copy " << adb_debug_prop_src << " to " << kDebugRamdiskProp |
| << ": " << ec.message(); |
| } |
| if (access(userdebug_plat_sepolicy_cil_src, F_OK) == 0 && |
| !fs::copy_file(userdebug_plat_sepolicy_cil_src, kDebugRamdiskSEPolicy, ec)) { |
| LOG(WARNING) << "Can't copy " << userdebug_plat_sepolicy_cil_src << " to " |
| << kDebugRamdiskSEPolicy << ": " << ec.message(); |
| } |
| // setenv for second-stage init to read above kDebugRamdisk* files. |
| setenv("INIT_FORCE_DEBUGGABLE", "true", 1); |
| } |
| |
| if (ForceNormalBoot(cmdline, bootconfig)) { |
| mkdir("/first_stage_ramdisk", 0755); |
| PrepareSwitchRoot(); |
| // SwitchRoot() must be called with a mount point as the target, so we bind mount the |
| // target directory to itself here. |
| if (mount("/first_stage_ramdisk", "/first_stage_ramdisk", nullptr, MS_BIND, nullptr) != 0) { |
| PLOG(FATAL) << "Could not bind mount /first_stage_ramdisk to itself"; |
| } |
| SwitchRoot("/first_stage_ramdisk"); |
| } |
| |
| if (IsRecoveryMode()) { |
| LOG(INFO) << "First stage mount skipped (recovery mode)"; |
| } else { |
| if (!fsm) { |
| fsm = CreateFirstStageMount(cmdline); |
| } |
| if (!fsm) { |
| LOG(FATAL) << "FirstStageMount not available"; |
| } |
| |
| if (!created_devices && !fsm->DoCreateDevices()) { |
| LOG(FATAL) << "Failed to create devices required for first stage mount"; |
| } |
| |
| if (!fsm->DoFirstStageMount()) { |
| LOG(FATAL) << "Failed to mount required partitions early ..."; |
| } |
| } |
| |
| struct stat new_root_info {}; |
| if (stat("/", &new_root_info) != 0) { |
| PLOG(ERROR) << "Could not stat(\"/\"), not freeing ramdisk"; |
| old_root_dir.reset(); |
| } |
| |
| if (old_root_dir && old_root_info.st_dev != new_root_info.st_dev) { |
| FreeRamdisk(old_root_dir.get(), old_root_info.st_dev); |
| } |
| |
| SetInitAvbVersionInRecovery(); |
| |
| setenv(kEnvFirstStageStartedAt, std::to_string(start_time.time_since_epoch().count()).c_str(), |
| 1); |
| |
| const char* path = "/system/bin/init"; |
| const char* args[] = {path, "selinux_setup", nullptr}; |
| auto fd = open("/dev/kmsg", O_WRONLY | O_CLOEXEC); |
| dup2(fd, STDOUT_FILENO); |
| dup2(fd, STDERR_FILENO); |
| close(fd); |
| execv(path, const_cast<char**>(args)); |
| |
| // execv() only returns if an error happened, in which case we |
| // panic and never fall through this conditional. |
| PLOG(FATAL) << "execv(\"" << path << "\") failed"; |
| |
| return 1; |
| } |
| |
| } // namespace init |
| } // namespace android |