| // Copyright (c) 2012 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "login_manager/system_utils_impl.h" |
| |
| #include <errno.h> |
| #include <signal.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <sys/errno.h> |
| #include <sys/stat.h> |
| #include <sys/wait.h> |
| #include <time.h> |
| #include <unistd.h> |
| |
| #include <limits> |
| #include <string> |
| #include <vector> |
| |
| #include <base/files/file_path.h> |
| #include <base/files/file_util.h> |
| #include <base/files/important_file_writer.h> |
| #include <base/files/scoped_temp_dir.h> |
| #include <base/logging.h> |
| #include <base/process/launch.h> |
| #include <base/strings/string_util.h> |
| #include <base/sys_info.h> |
| #include <base/time/time.h> |
| #include <brillo/process.h> |
| #include <chromeos/dbus/service_constants.h> |
| |
| using std::string; |
| using std::vector; |
| |
| namespace login_manager { |
| |
| namespace { |
| |
| bool LaunchAndWait(const vector<string>& argv, int* out_exit_code) { |
| base::Process process(base::LaunchProcess(argv, base::LaunchOptions())); |
| if (!process.IsValid()) { |
| PLOG(ERROR) << "Failed to create a process for '" |
| << base::JoinString(argv, " ") << "'"; |
| return false; |
| } |
| if (!process.WaitForExit(out_exit_code)) { |
| PLOG(ERROR) << "Failed to wait for '" << base::JoinString(argv, " ") |
| << "' to exit"; |
| return false; |
| } |
| return true; |
| } |
| |
| } // namespace |
| |
| SystemUtilsImpl::SystemUtilsImpl() |
| : dev_mode_state_(DevModeState::DEV_MODE_UNKNOWN), |
| vm_state_(VmState::UNKNOWN) { |
| } |
| |
| SystemUtilsImpl::~SystemUtilsImpl() { |
| } |
| |
| DevModeState SystemUtilsImpl::GetDevModeState() { |
| // Return the cached result when possible. There is no reason to run |
| // crossytem twice as cros_debug is always read-only. |
| if (dev_mode_state_ == DevModeState::DEV_MODE_UNKNOWN) { |
| int exit_code = -1; |
| if (LaunchAndWait({"crossystem", "cros_debug?0"}, &exit_code)) { |
| switch (exit_code) { |
| case 0: |
| dev_mode_state_ = DevModeState::DEV_MODE_OFF; |
| break; |
| case 1: |
| dev_mode_state_ = DevModeState::DEV_MODE_ON; |
| break; |
| default: |
| LOG(ERROR) << "Unexpected exit code from crossystem: " << exit_code; |
| break; |
| } |
| } |
| } |
| return dev_mode_state_; |
| } |
| |
| VmState SystemUtilsImpl::GetVmState() { |
| // Return the cached result when possible. There is no reason to run |
| // crossystem twice as inside_vm is always read-only. |
| if (vm_state_ == VmState::UNKNOWN) { |
| int exit_code = -1; |
| if (LaunchAndWait({"crossystem", "inside_vm?0"}, &exit_code)) { |
| switch (exit_code) { |
| case 0: |
| vm_state_ = VmState::OUTSIDE_VM; |
| break; |
| case 1: |
| vm_state_ = VmState::INSIDE_VM; |
| break; |
| default: |
| LOG(ERROR) << "Unexpected exit code from crossystem: " << exit_code; |
| break; |
| } |
| } |
| } |
| return vm_state_; |
| } |
| |
| int SystemUtilsImpl::kill(pid_t pid, uid_t owner, int signal) { |
| LOG(INFO) << "Sending " << signal << " to " << pid << " as " << owner; |
| uid_t uid, euid, suid; |
| getresuid(&uid, &euid, &suid); |
| if (setresuid(owner, owner, -1)) { |
| PLOG(ERROR) << "Couldn't assume uid " << owner; |
| return -1; |
| } |
| int ret = ::kill(pid, signal); |
| if (setresuid(uid, euid, -1)) { |
| PLOG(ERROR) << "Couldn't return to root"; |
| return -1; |
| } |
| return ret; |
| } |
| |
| time_t SystemUtilsImpl::time(time_t* t) { |
| return ::time(t); |
| } |
| |
| pid_t SystemUtilsImpl::fork() { |
| return ::fork(); |
| } |
| |
| bool SystemUtilsImpl::ProcessGroupIsGone(pid_t child_spec, |
| base::TimeDelta timeout) { |
| base::TimeTicks start = base::TimeTicks::Now(); |
| base::TimeDelta elapsed; |
| int ret; |
| |
| DCHECK_GE(timeout.InSeconds(), 0); |
| DCHECK_LE(timeout.InSeconds(), |
| static_cast<int64_t>(std::numeric_limits<int>::max())); |
| alarm(static_cast<int32_t>(timeout.InSeconds())); |
| do { |
| errno = 0; |
| ret = ::waitpid(-child_spec, NULL, 0); |
| elapsed = base::TimeTicks::Now() - start; |
| } while (ret > 0 || (errno == EINTR && elapsed < timeout)); |
| |
| // Once we exit the loop, we know there was an error. |
| alarm(0); |
| return errno == ECHILD; // EINTR means we timed out. |
| } |
| |
| bool SystemUtilsImpl::EnsureAndReturnSafeFileSize(const base::FilePath& file, |
| int32_t* file_size_32) { |
| const base::FilePath file_in_base_dir = PutInsideBaseDir(file); |
| // Get the file size (must fit in a 32 bit int for NSS). |
| int64_t file_size; |
| if (!base::GetFileSize(file_in_base_dir, &file_size)) { |
| LOG(ERROR) << "Could not get size of " << file_in_base_dir.value(); |
| return false; |
| } |
| if (file_size > static_cast<int64_t>(std::numeric_limits<int32_t>::max())) { |
| LOG(ERROR) << file_in_base_dir.value() << "is " << file_size |
| << "bytes!!! Too big!"; |
| return false; |
| } |
| *file_size_32 = static_cast<int32_t>(file_size); |
| return true; |
| } |
| |
| bool SystemUtilsImpl::Exists(const base::FilePath& file) { |
| return base::PathExists(PutInsideBaseDir(file)); |
| } |
| |
| bool SystemUtilsImpl::CreateReadOnlyFileInTempDir(base::FilePath* temp_file) { |
| if (!temp_dir_.IsValid() && !temp_dir_.CreateUniqueTempDir()) |
| return false; |
| base::FilePath local_temp_file; |
| if (base::CreateTemporaryFileInDir(temp_dir_.path(), &local_temp_file)) { |
| if (chmod(local_temp_file.value().c_str(), 0644) == 0) { |
| *temp_file = local_temp_file; |
| return true; |
| } else { |
| PLOG(ERROR) << "Can't chmod " << local_temp_file.value() << " to 0644."; |
| } |
| RemoveFile(local_temp_file); |
| } |
| return false; |
| } |
| |
| bool SystemUtilsImpl::GetUniqueFilenameInWriteOnlyTempDir( |
| base::FilePath* temp_file_path) { |
| // Create a temporary directory to put the testing channel in. |
| // It will be made write-only below; we need to be able to read it |
| // when trying to create a unique name inside it. |
| base::FilePath temp_dir_path; |
| if (!base::CreateNewTempDirectory(FILE_PATH_LITERAL(""), &temp_dir_path)) { |
| PLOG(ERROR) << "Can't create temp dir"; |
| return false; |
| } |
| // Create a temporary file in the temporary directory, to be deleted later. |
| // This ensures a unique name. |
| if (!base::CreateTemporaryFileInDir(temp_dir_path, temp_file_path)) { |
| PLOG(ERROR) << "Can't get temp file name in " << temp_dir_path.value(); |
| return false; |
| } |
| // Now, allow access to non-root processes. |
| if (chmod(temp_dir_path.value().c_str(), 0333)) { |
| PLOG(ERROR) << "Can't chmod " << temp_file_path->value() << " to 0333."; |
| return false; |
| } |
| if (!RemoveFile(*temp_file_path)) { |
| PLOG(ERROR) << "Can't clear temp file in " << temp_file_path->value(); |
| return false; |
| } |
| return true; |
| } |
| |
| bool SystemUtilsImpl::RemoveDirTree(const base::FilePath& dir) { |
| const base::FilePath dir_in_base_dir = PutInsideBaseDir(dir); |
| if (!base::DirectoryExists(dir_in_base_dir)) |
| return false; |
| return base::DeleteFile(dir_in_base_dir, true); |
| } |
| |
| bool SystemUtilsImpl::RemoveFile(const base::FilePath& filename) { |
| const base::FilePath filename_in_base_dir = PutInsideBaseDir(filename); |
| if (base::DirectoryExists(filename_in_base_dir)) |
| return false; |
| return base::DeleteFile(filename_in_base_dir, false); |
| } |
| |
| bool SystemUtilsImpl::AtomicFileWrite(const base::FilePath& filename, |
| const std::string& data) { |
| const base::FilePath filename_in_base_dir = PutInsideBaseDir(filename); |
| return ( |
| base::ImportantFileWriter::WriteFileAtomically( |
| filename_in_base_dir, data) && |
| base::SetPosixFilePermissions( |
| filename_in_base_dir, (S_IRUSR | S_IWUSR | S_IROTH))); |
| } |
| |
| bool SystemUtilsImpl::DirectoryExists(const base::FilePath& dir) { |
| return base::DirectoryExists(PutInsideBaseDir(dir)); |
| } |
| |
| bool SystemUtilsImpl::CreateTemporaryDirIn(const base::FilePath& parent_dir, |
| base::FilePath* out_dir) { |
| return base::CreateTemporaryDirInDir( |
| PutInsideBaseDir(parent_dir), "temp", out_dir); |
| } |
| |
| bool SystemUtilsImpl::RenameDir(const base::FilePath& source, |
| const base::FilePath& target) { |
| const base::FilePath source_in_base_dir = PutInsideBaseDir(source); |
| if (!base::DirectoryExists(source_in_base_dir)) |
| return false; |
| return base::ReplaceFile( |
| source_in_base_dir, PutInsideBaseDir(target), nullptr); |
| } |
| |
| bool SystemUtilsImpl::CreateDir(const base::FilePath& dir) { |
| return base::CreateDirectoryAndGetError(PutInsideBaseDir(dir), nullptr); |
| } |
| |
| bool SystemUtilsImpl::IsDirectoryEmpty(const base::FilePath& dir) { |
| const base::FilePath dir_in_base_dir = PutInsideBaseDir(dir); |
| return !base::DirectoryExists(dir_in_base_dir) || |
| base::IsDirectoryEmpty(dir_in_base_dir); |
| } |
| |
| int64_t SystemUtilsImpl::AmountOfFreeDiskSpace(const base::FilePath& path) { |
| return base::SysInfo::AmountOfFreeDiskSpace(path); |
| } |
| |
| base::FilePath SystemUtilsImpl::PutInsideBaseDirForTesting( |
| const base::FilePath& path) { |
| return PutInsideBaseDir(path); |
| } |
| |
| base::FilePath SystemUtilsImpl::PutInsideBaseDir(const base::FilePath& path) { |
| if (base_dir_for_testing_.empty()) |
| return path; // for production, this function does nothing. |
| |
| if (base_dir_for_testing_.IsParent(path)) |
| return path; // already chroot'ed. |
| |
| base::FilePath to_append(path); |
| while (to_append.IsAbsolute()) { |
| std::string ascii(path.MaybeAsASCII()); |
| to_append = base::FilePath(ascii.substr(1, std::string::npos)); |
| } |
| return base_dir_for_testing_.Append(to_append); |
| } |
| |
| } // namespace login_manager |