| /* |
| * Copyright (C) 2008 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 "util.h" |
| |
| #include <ctype.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <pwd.h> |
| #include <signal.h> |
| #include <stdarg.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/socket.h> |
| #include <sys/un.h> |
| #include <time.h> |
| #include <unistd.h> |
| |
| #include <thread> |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/properties.h> |
| #include <android-base/scopeguard.h> |
| #include <android-base/strings.h> |
| #include <android-base/unique_fd.h> |
| #include <cutils/sockets.h> |
| #include <selinux/android.h> |
| |
| #ifdef INIT_FULL_SOURCES |
| #include <android/api-level.h> |
| #include <sys/system_properties.h> |
| |
| #include "reboot_utils.h" |
| #include "selabel.h" |
| #include "selinux.h" |
| #else |
| #include "host_init_stubs.h" |
| #endif |
| |
| using android::base::boot_clock; |
| using android::base::StartsWith; |
| using namespace std::literals::string_literals; |
| |
| namespace android { |
| namespace init { |
| |
| const std::string kDefaultAndroidDtDir("/proc/device-tree/firmware/android/"); |
| |
| void (*trigger_shutdown)(const std::string& command) = nullptr; |
| |
| // DecodeUid() - decodes and returns the given string, which can be either the |
| // numeric or name representation, into the integer uid or gid. |
| Result<uid_t> DecodeUid(const std::string& name) { |
| if (isalpha(name[0])) { |
| passwd* pwd = getpwnam(name.c_str()); |
| if (!pwd) return ErrnoError() << "getpwnam failed"; |
| |
| return pwd->pw_uid; |
| } |
| |
| errno = 0; |
| uid_t result = static_cast<uid_t>(strtoul(name.c_str(), 0, 0)); |
| if (errno) return ErrnoError() << "strtoul failed"; |
| |
| return result; |
| } |
| |
| /* |
| * CreateSocket - creates a Unix domain socket in ANDROID_SOCKET_DIR |
| * ("/dev/socket") as dictated in init.rc. This socket is inherited by the |
| * daemon. We communicate the file descriptor's value via the environment |
| * variable ANDROID_SOCKET_ENV_PREFIX<name> ("ANDROID_SOCKET_foo"). |
| */ |
| Result<int> CreateSocket(const std::string& name, int type, bool passcred, mode_t perm, uid_t uid, |
| gid_t gid, const std::string& socketcon) { |
| if (!socketcon.empty()) { |
| if (setsockcreatecon(socketcon.c_str()) == -1) { |
| return ErrnoError() << "setsockcreatecon(\"" << socketcon << "\") failed"; |
| } |
| } |
| |
| android::base::unique_fd fd(socket(PF_UNIX, type, 0)); |
| if (fd < 0) { |
| return ErrnoError() << "Failed to open socket '" << name << "'"; |
| } |
| |
| if (!socketcon.empty()) setsockcreatecon(nullptr); |
| |
| struct sockaddr_un addr; |
| memset(&addr, 0 , sizeof(addr)); |
| addr.sun_family = AF_UNIX; |
| snprintf(addr.sun_path, sizeof(addr.sun_path), ANDROID_SOCKET_DIR "/%s", name.c_str()); |
| |
| if ((unlink(addr.sun_path) != 0) && (errno != ENOENT)) { |
| return ErrnoError() << "Failed to unlink old socket '" << name << "'"; |
| } |
| |
| std::string secontext; |
| if (SelabelLookupFileContext(addr.sun_path, S_IFSOCK, &secontext) && !secontext.empty()) { |
| setfscreatecon(secontext.c_str()); |
| } |
| |
| if (passcred) { |
| int on = 1; |
| if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) { |
| return ErrnoError() << "Failed to set SO_PASSCRED '" << name << "'"; |
| } |
| } |
| |
| int ret = bind(fd, (struct sockaddr *) &addr, sizeof (addr)); |
| int savederrno = errno; |
| |
| if (!secontext.empty()) { |
| setfscreatecon(nullptr); |
| } |
| |
| auto guard = android::base::make_scope_guard([&addr] { unlink(addr.sun_path); }); |
| |
| if (ret) { |
| errno = savederrno; |
| return ErrnoError() << "Failed to bind socket '" << name << "'"; |
| } |
| |
| if (lchown(addr.sun_path, uid, gid)) { |
| return ErrnoError() << "Failed to lchown socket '" << addr.sun_path << "'"; |
| } |
| if (fchmodat(AT_FDCWD, addr.sun_path, perm, AT_SYMLINK_NOFOLLOW)) { |
| return ErrnoError() << "Failed to fchmodat socket '" << addr.sun_path << "'"; |
| } |
| |
| LOG(INFO) << "Created socket '" << addr.sun_path << "'" |
| << ", mode " << std::oct << perm << std::dec |
| << ", user " << uid |
| << ", group " << gid; |
| |
| guard.Disable(); |
| return fd.release(); |
| } |
| |
| Result<std::string> ReadFile(const std::string& path) { |
| android::base::unique_fd fd( |
| TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC))); |
| if (fd == -1) { |
| return ErrnoError() << "open() failed"; |
| } |
| |
| // For security reasons, disallow world-writable |
| // or group-writable files. |
| struct stat sb; |
| if (fstat(fd, &sb) == -1) { |
| return ErrnoError() << "fstat failed()"; |
| } |
| if ((sb.st_mode & (S_IWGRP | S_IWOTH)) != 0) { |
| return Error() << "Skipping insecure file"; |
| } |
| |
| std::string content; |
| if (!android::base::ReadFdToString(fd, &content)) { |
| return ErrnoError() << "Unable to read file contents"; |
| } |
| return content; |
| } |
| |
| static int OpenFile(const std::string& path, int flags, mode_t mode) { |
| std::string secontext; |
| if (SelabelLookupFileContext(path, mode, &secontext) && !secontext.empty()) { |
| setfscreatecon(secontext.c_str()); |
| } |
| |
| int rc = open(path.c_str(), flags, mode); |
| |
| if (!secontext.empty()) { |
| int save_errno = errno; |
| setfscreatecon(nullptr); |
| errno = save_errno; |
| } |
| |
| return rc; |
| } |
| |
| Result<void> WriteFile(const std::string& path, const std::string& content) { |
| android::base::unique_fd fd(TEMP_FAILURE_RETRY( |
| OpenFile(path, O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC | O_CLOEXEC, 0600))); |
| if (fd == -1) { |
| return ErrnoError() << "open() failed"; |
| } |
| if (!android::base::WriteStringToFd(content, fd)) { |
| return ErrnoError() << "Unable to write file contents"; |
| } |
| return {}; |
| } |
| |
| bool mkdir_recursive(const std::string& path, mode_t mode) { |
| std::string::size_type slash = 0; |
| while ((slash = path.find('/', slash + 1)) != std::string::npos) { |
| auto directory = path.substr(0, slash); |
| struct stat info; |
| if (stat(directory.c_str(), &info) != 0) { |
| auto ret = make_dir(directory, mode); |
| if (!ret && errno != EEXIST) return false; |
| } |
| } |
| auto ret = make_dir(path, mode); |
| if (!ret && errno != EEXIST) return false; |
| return true; |
| } |
| |
| int wait_for_file(const char* filename, std::chrono::nanoseconds timeout) { |
| android::base::Timer t; |
| while (t.duration() < timeout) { |
| struct stat sb; |
| if (stat(filename, &sb) != -1) { |
| LOG(INFO) << "wait for '" << filename << "' took " << t; |
| return 0; |
| } |
| std::this_thread::sleep_for(10ms); |
| } |
| LOG(WARNING) << "wait for '" << filename << "' timed out and took " << t; |
| return -1; |
| } |
| |
| void ImportKernelCmdline(const std::function<void(const std::string&, const std::string&)>& fn) { |
| std::string cmdline; |
| android::base::ReadFileToString("/proc/cmdline", &cmdline); |
| |
| for (const auto& entry : android::base::Split(android::base::Trim(cmdline), " ")) { |
| std::vector<std::string> pieces = android::base::Split(entry, "="); |
| if (pieces.size() == 2) { |
| fn(pieces[0], pieces[1]); |
| } |
| } |
| } |
| |
| bool make_dir(const std::string& path, mode_t mode) { |
| std::string secontext; |
| if (SelabelLookupFileContext(path, mode, &secontext) && !secontext.empty()) { |
| setfscreatecon(secontext.c_str()); |
| } |
| |
| int rc = mkdir(path.c_str(), mode); |
| |
| if (!secontext.empty()) { |
| int save_errno = errno; |
| setfscreatecon(nullptr); |
| errno = save_errno; |
| } |
| |
| return rc == 0; |
| } |
| |
| /* |
| * Returns true is pathname is a directory |
| */ |
| bool is_dir(const char* pathname) { |
| struct stat info; |
| if (stat(pathname, &info) == -1) { |
| return false; |
| } |
| return S_ISDIR(info.st_mode); |
| } |
| |
| Result<std::string> ExpandProps(const std::string& src) { |
| const char* src_ptr = src.c_str(); |
| |
| std::string dst; |
| |
| /* - variables can either be $x.y or ${x.y}, in case they are only part |
| * of the string. |
| * - will accept $$ as a literal $. |
| * - no nested property expansion, i.e. ${foo.${bar}} is not supported, |
| * bad things will happen |
| * - ${x.y:-default} will return default value if property empty. |
| */ |
| while (*src_ptr) { |
| const char* c; |
| |
| c = strchr(src_ptr, '$'); |
| if (!c) { |
| dst.append(src_ptr); |
| return dst; |
| } |
| |
| dst.append(src_ptr, c); |
| c++; |
| |
| if (*c == '$') { |
| dst.push_back(*(c++)); |
| src_ptr = c; |
| continue; |
| } else if (*c == '\0') { |
| return dst; |
| } |
| |
| std::string prop_name; |
| std::string def_val; |
| if (*c == '{') { |
| c++; |
| const char* end = strchr(c, '}'); |
| if (!end) { |
| // failed to find closing brace, abort. |
| return Error() << "unexpected end of string in '" << src << "', looking for }"; |
| } |
| prop_name = std::string(c, end); |
| c = end + 1; |
| size_t def = prop_name.find(":-"); |
| if (def < prop_name.size()) { |
| def_val = prop_name.substr(def + 2); |
| prop_name = prop_name.substr(0, def); |
| } |
| } else { |
| prop_name = c; |
| if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_R__) { |
| return Error() << "using deprecated syntax for specifying property '" << c |
| << "', use ${name} instead"; |
| } else { |
| LOG(ERROR) << "using deprecated syntax for specifying property '" << c |
| << "', use ${name} instead"; |
| } |
| c += prop_name.size(); |
| } |
| |
| if (prop_name.empty()) { |
| return Error() << "invalid zero-length property name in '" << src << "'"; |
| } |
| |
| std::string prop_val = android::base::GetProperty(prop_name, ""); |
| if (prop_val.empty()) { |
| if (def_val.empty()) { |
| return Error() << "property '" << prop_name << "' doesn't exist while expanding '" |
| << src << "'"; |
| } |
| prop_val = def_val; |
| } |
| |
| dst.append(prop_val); |
| src_ptr = c; |
| } |
| |
| return dst; |
| } |
| |
| static std::string init_android_dt_dir() { |
| // Use the standard procfs-based path by default |
| std::string android_dt_dir = kDefaultAndroidDtDir; |
| // The platform may specify a custom Android DT path in kernel cmdline |
| ImportKernelCmdline([&](const std::string& key, const std::string& value) { |
| if (key == "androidboot.android_dt_dir") { |
| android_dt_dir = value; |
| } |
| }); |
| LOG(INFO) << "Using Android DT directory " << android_dt_dir; |
| return android_dt_dir; |
| } |
| |
| // FIXME: The same logic is duplicated in system/core/fs_mgr/ |
| const std::string& get_android_dt_dir() { |
| // Set once and saves time for subsequent calls to this function |
| static const std::string kAndroidDtDir = init_android_dt_dir(); |
| return kAndroidDtDir; |
| } |
| |
| // Reads the content of device tree file under the platform's Android DT directory. |
| // Returns true if the read is success, false otherwise. |
| bool read_android_dt_file(const std::string& sub_path, std::string* dt_content) { |
| const std::string file_name = get_android_dt_dir() + sub_path; |
| if (android::base::ReadFileToString(file_name, dt_content)) { |
| if (!dt_content->empty()) { |
| dt_content->pop_back(); // Trims the trailing '\0' out. |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| bool is_android_dt_value_expected(const std::string& sub_path, const std::string& expected_content) { |
| std::string dt_content; |
| if (read_android_dt_file(sub_path, &dt_content)) { |
| if (dt_content == expected_content) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| bool IsLegalPropertyName(const std::string& name) { |
| size_t namelen = name.size(); |
| |
| if (namelen < 1) return false; |
| if (name[0] == '.') return false; |
| if (name[namelen - 1] == '.') return false; |
| |
| /* Only allow alphanumeric, plus '.', '-', '@', ':', or '_' */ |
| /* Don't allow ".." to appear in a property name */ |
| for (size_t i = 0; i < namelen; i++) { |
| if (name[i] == '.') { |
| // i=0 is guaranteed to never have a dot. See above. |
| if (name[i - 1] == '.') return false; |
| continue; |
| } |
| if (name[i] == '_' || name[i] == '-' || name[i] == '@' || name[i] == ':') continue; |
| if (name[i] >= 'a' && name[i] <= 'z') continue; |
| if (name[i] >= 'A' && name[i] <= 'Z') continue; |
| if (name[i] >= '0' && name[i] <= '9') continue; |
| return false; |
| } |
| |
| return true; |
| } |
| |
| Result<void> IsLegalPropertyValue(const std::string& name, const std::string& value) { |
| if (value.size() >= PROP_VALUE_MAX && !StartsWith(name, "ro.")) { |
| return Error() << "Property value too long"; |
| } |
| |
| if (mbstowcs(nullptr, value.data(), 0) == static_cast<std::size_t>(-1)) { |
| return Error() << "Value is not a UTF8 encoded string"; |
| } |
| |
| return {}; |
| } |
| |
| static FscryptAction FscryptInferAction(const std::string& dir) { |
| const std::string prefix = "/data/"; |
| |
| if (!android::base::StartsWith(dir, prefix)) { |
| return FscryptAction::kNone; |
| } |
| |
| // Special-case /data/media/obb per b/64566063 |
| if (dir == "/data/media/obb") { |
| // Try to set policy on this directory, but if it is non-empty this may fail. |
| return FscryptAction::kAttempt; |
| } |
| |
| // Only set policy on first level /data directories |
| // To make this less restrictive, consider using a policy file. |
| // However this is overkill for as long as the policy is simply |
| // to apply a global policy to all /data folders created via makedir |
| if (dir.find_first_of('/', prefix.size()) != std::string::npos) { |
| return FscryptAction::kNone; |
| } |
| |
| // Special case various directories that must not be encrypted, |
| // often because their subdirectories must be encrypted. |
| // This isn't a nice way to do this, see b/26641735 |
| std::vector<std::string> directories_to_exclude = { |
| "lost+found", "system_ce", "system_de", "misc_ce", "misc_de", |
| "vendor_ce", "vendor_de", "media", "data", "user", |
| "user_de", "apex", "preloads", "app-staging", "gsi", |
| }; |
| for (const auto& d : directories_to_exclude) { |
| if ((prefix + d) == dir) { |
| return FscryptAction::kNone; |
| } |
| } |
| // Empty these directories if policy setting fails. |
| std::vector<std::string> wipe_on_failure = { |
| "rollback", "rollback-observer", // b/139193659 |
| }; |
| for (const auto& d : wipe_on_failure) { |
| if ((prefix + d) == dir) { |
| return FscryptAction::kDeleteIfNecessary; |
| } |
| } |
| return FscryptAction::kRequire; |
| } |
| |
| Result<MkdirOptions> ParseMkdir(const std::vector<std::string>& args) { |
| mode_t mode = 0755; |
| Result<uid_t> uid = -1; |
| Result<gid_t> gid = -1; |
| FscryptAction fscrypt_inferred_action = FscryptInferAction(args[1]); |
| FscryptAction fscrypt_action = fscrypt_inferred_action; |
| std::string ref_option = "ref"; |
| bool set_option_encryption = false; |
| bool set_option_key = false; |
| |
| for (size_t i = 2; i < args.size(); i++) { |
| switch (i) { |
| case 2: |
| mode = std::strtoul(args[2].c_str(), 0, 8); |
| break; |
| case 3: |
| uid = DecodeUid(args[3]); |
| if (!uid.ok()) { |
| return Error() |
| << "Unable to decode UID for '" << args[3] << "': " << uid.error(); |
| } |
| break; |
| case 4: |
| gid = DecodeUid(args[4]); |
| if (!gid.ok()) { |
| return Error() |
| << "Unable to decode GID for '" << args[4] << "': " << gid.error(); |
| } |
| break; |
| default: |
| auto parts = android::base::Split(args[i], "="); |
| if (parts.size() != 2) { |
| return Error() << "Can't parse option: '" << args[i] << "'"; |
| } |
| auto optname = parts[0]; |
| auto optval = parts[1]; |
| if (optname == "encryption") { |
| if (set_option_encryption) { |
| return Error() << "Duplicated option: '" << optname << "'"; |
| } |
| if (optval == "Require") { |
| fscrypt_action = FscryptAction::kRequire; |
| } else if (optval == "None") { |
| fscrypt_action = FscryptAction::kNone; |
| } else if (optval == "Attempt") { |
| fscrypt_action = FscryptAction::kAttempt; |
| } else if (optval == "DeleteIfNecessary") { |
| fscrypt_action = FscryptAction::kDeleteIfNecessary; |
| } else { |
| return Error() << "Unknown encryption option: '" << optval << "'"; |
| } |
| set_option_encryption = true; |
| } else if (optname == "key") { |
| if (set_option_key) { |
| return Error() << "Duplicated option: '" << optname << "'"; |
| } |
| if (optval == "ref" || optval == "per_boot_ref") { |
| ref_option = optval; |
| } else { |
| return Error() << "Unknown key option: '" << optval << "'"; |
| } |
| set_option_key = true; |
| } else { |
| return Error() << "Unknown option: '" << args[i] << "'"; |
| } |
| } |
| } |
| if (set_option_key && fscrypt_action == FscryptAction::kNone) { |
| return Error() << "Key option set but encryption action is none"; |
| } |
| const std::string prefix = "/data/"; |
| if (StartsWith(args[1], prefix) && |
| args[1].find_first_of('/', prefix.size()) == std::string::npos) { |
| if (!set_option_encryption) { |
| LOG(WARNING) << "Top-level directory needs encryption action, eg mkdir " << args[1] |
| << " <mode> <uid> <gid> encryption=Require"; |
| } |
| if (fscrypt_action == FscryptAction::kNone) { |
| LOG(INFO) << "Not setting encryption policy on: " << args[1]; |
| } |
| } |
| if (fscrypt_action != fscrypt_inferred_action) { |
| LOG(WARNING) << "Inferred action different from explicit one, expected " |
| << static_cast<int>(fscrypt_inferred_action) << " but got " |
| << static_cast<int>(fscrypt_action); |
| } |
| |
| return MkdirOptions{args[1], mode, *uid, *gid, fscrypt_action, ref_option}; |
| } |
| |
| Result<MountAllOptions> ParseMountAll(const std::vector<std::string>& args) { |
| bool compat_mode = false; |
| bool import_rc = false; |
| if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) { |
| if (args.size() <= 1) { |
| return Error() << "mount_all requires at least 1 argument"; |
| } |
| compat_mode = true; |
| import_rc = true; |
| } |
| |
| std::size_t first_option_arg = args.size(); |
| enum mount_mode mode = MOUNT_MODE_DEFAULT; |
| |
| // If we are <= Q, then stop looking for non-fstab arguments at slot 2. |
| // Otherwise, stop looking at slot 1 (as the fstab path argument is optional >= R). |
| for (std::size_t na = args.size() - 1; na > (compat_mode ? 1 : 0); --na) { |
| if (args[na] == "--early") { |
| first_option_arg = na; |
| mode = MOUNT_MODE_EARLY; |
| } else if (args[na] == "--late") { |
| first_option_arg = na; |
| mode = MOUNT_MODE_LATE; |
| import_rc = false; |
| } |
| } |
| |
| std::string fstab_path; |
| if (first_option_arg > 1) { |
| fstab_path = args[1]; |
| } else if (compat_mode) { |
| return Error() << "mount_all argument 1 must be the fstab path"; |
| } |
| |
| std::vector<std::string> rc_paths; |
| for (std::size_t na = 2; na < first_option_arg; ++na) { |
| rc_paths.push_back(args[na]); |
| } |
| |
| return MountAllOptions{rc_paths, fstab_path, mode, import_rc}; |
| } |
| |
| Result<std::pair<int, std::vector<std::string>>> ParseRestorecon( |
| const std::vector<std::string>& args) { |
| struct flag_type { |
| const char* name; |
| int value; |
| }; |
| static const flag_type flags[] = { |
| {"--recursive", SELINUX_ANDROID_RESTORECON_RECURSE}, |
| {"--skip-ce", SELINUX_ANDROID_RESTORECON_SKIPCE}, |
| {"--cross-filesystems", SELINUX_ANDROID_RESTORECON_CROSS_FILESYSTEMS}, |
| {0, 0}}; |
| |
| int flag = 0; |
| std::vector<std::string> paths; |
| |
| bool in_flags = true; |
| for (size_t i = 1; i < args.size(); ++i) { |
| if (android::base::StartsWith(args[i], "--")) { |
| if (!in_flags) { |
| return Error() << "flags must precede paths"; |
| } |
| bool found = false; |
| for (size_t j = 0; flags[j].name; ++j) { |
| if (args[i] == flags[j].name) { |
| flag |= flags[j].value; |
| found = true; |
| break; |
| } |
| } |
| if (!found) { |
| return Error() << "bad flag " << args[i]; |
| } |
| } else { |
| in_flags = false; |
| paths.emplace_back(args[i]); |
| } |
| } |
| return std::pair(flag, paths); |
| } |
| |
| Result<std::string> ParseSwaponAll(const std::vector<std::string>& args) { |
| if (args.size() <= 1) { |
| if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) { |
| return Error() << "swapon_all requires at least 1 argument"; |
| } |
| return {}; |
| } |
| return args[1]; |
| } |
| |
| Result<std::string> ParseUmountAll(const std::vector<std::string>& args) { |
| if (args.size() <= 1) { |
| if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) { |
| return Error() << "umount_all requires at least 1 argument"; |
| } |
| return {}; |
| } |
| return args[1]; |
| } |
| |
| static void InitAborter(const char* abort_message) { |
| // When init forks, it continues to use this aborter for LOG(FATAL), but we want children to |
| // simply abort instead of trying to reboot the system. |
| if (getpid() != 1) { |
| android::base::DefaultAborter(abort_message); |
| return; |
| } |
| |
| InitFatalReboot(SIGABRT); |
| } |
| |
| // The kernel opens /dev/console and uses that fd for stdin/stdout/stderr if there is a serial |
| // console enabled and no initramfs, otherwise it does not provide any fds for stdin/stdout/stderr. |
| // SetStdioToDevNull() is used to close these existing fds if they exist and replace them with |
| // /dev/null regardless. |
| // |
| // In the case that these fds are provided by the kernel, the exec of second stage init causes an |
| // SELinux denial as it does not have access to /dev/console. In the case that they are not |
| // provided, exec of any further process is potentially dangerous as the first fd's opened by that |
| // process will take the stdin/stdout/stderr fileno's, which can cause issues if printf(), etc is |
| // then used by that process. |
| // |
| // Lastly, simply calling SetStdioToDevNull() in first stage init is not enough, since first |
| // stage init still runs in kernel context, future child processes will not have permissions to |
| // access any fds that it opens, including the one opened below for /dev/null. Therefore, |
| // SetStdioToDevNull() must be called again in second stage init. |
| void SetStdioToDevNull(char** argv) { |
| // Make stdin/stdout/stderr all point to /dev/null. |
| int fd = open("/dev/null", O_RDWR); // NOLINT(android-cloexec-open) |
| if (fd == -1) { |
| int saved_errno = errno; |
| android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter); |
| errno = saved_errno; |
| PLOG(FATAL) << "Couldn't open /dev/null"; |
| } |
| dup2(fd, STDIN_FILENO); |
| dup2(fd, STDOUT_FILENO); |
| dup2(fd, STDERR_FILENO); |
| if (fd > STDERR_FILENO) close(fd); |
| } |
| |
| void InitKernelLogging(char** argv) { |
| SetFatalRebootTarget(); |
| android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter); |
| } |
| |
| bool IsRecoveryMode() { |
| return access("/system/bin/recovery", F_OK) == 0; |
| } |
| |
| } // namespace init |
| } // namespace android |