// Copyright (c) 2012 The Chromium 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 "base/linux_util.h" #include #include #include #include #include #include #include #include #include #include #include "base/base_export.h" #include "base/files/dir_reader_posix.h" #include "base/files/file_util.h" #include "base/files/scoped_file.h" #include "base/strings/safe_sprintf.h" #include "base/strings/string_number_conversions.h" #include "base/strings/string_split.h" #include "base/strings/string_tokenizer.h" #include "base/strings/string_util.h" #include "build/build_config.h" #include "build/chromeos_buildflags.h" namespace base { namespace { #if !BUILDFLAG(IS_CHROMEOS_ASH) std::string GetKeyValueFromOSReleaseFile(const std::string& input, const char* key) { StringPairs key_value_pairs; SplitStringIntoKeyValuePairs(input, '=', '\n', &key_value_pairs); for (const auto& pair : key_value_pairs) { const std::string& key_str = pair.first; const std::string& value_str = pair.second; if (key_str == key) { // It can contain quoted characters. std::stringstream ss; std::string pretty_name; ss << value_str; // Quoted with a single tick? if (value_str[0] == '\'') ss >> std::quoted(pretty_name, '\''); else ss >> std::quoted(pretty_name); return pretty_name; } } return ""; } bool ReadDistroFromOSReleaseFile(const char* file) { static const char kPrettyName[] = "PRETTY_NAME"; std::string os_release_content; if (!ReadFileToString(FilePath(file), &os_release_content)) return false; std::string pretty_name = GetKeyValueFromOSReleaseFile(os_release_content, kPrettyName); if (pretty_name.empty()) return false; SetLinuxDistro(pretty_name); return true; } // https://www.freedesktop.org/software/systemd/man/os-release.html class DistroNameGetter { public: DistroNameGetter() { static const char* const kFilesToCheck[] = {"/etc/os-release", "/usr/lib/os-release"}; for (const char* file : kFilesToCheck) { if (ReadDistroFromOSReleaseFile(file)) return; } } }; #endif // !BUILDFLAG(IS_CHROMEOS_ASH) // Account for the terminating null character. constexpr int kDistroSize = 128 + 1; } // namespace // We use this static string to hold the Linux distro info. If we // crash, the crash handler code will send this in the crash dump. char g_linux_distro[kDistroSize] = #if BUILDFLAG(IS_CHROMEOS_ASH) "CrOS"; #elif BUILDFLAG(IS_ANDROID) "Android"; #else "Unknown"; #endif // This function is only supposed to be used in tests. The declaration in the // header file is guarded by "#if defined(UNIT_TEST)" so that they can be used // by tests but not non-test code. However, this .cc file is compiled as part // of "base" where "UNIT_TEST" is not defined. So we need to specify // "BASE_EXPORT" here again so that they are visible to tests. BASE_EXPORT std::string GetKeyValueFromOSReleaseFileForTesting( const std::string& input, const char* key) { #if !BUILDFLAG(IS_CHROMEOS_ASH) return GetKeyValueFromOSReleaseFile(input, key); #else return ""; #endif // !BUILDFLAG(IS_CHROMEOS_ASH) } std::string GetLinuxDistro() { #if !BUILDFLAG(IS_CHROMEOS_ASH) // We do this check only once per process. If it fails, there's // little reason to believe it will work if we attempt to run it again. static DistroNameGetter distro_name_getter; #endif return g_linux_distro; } void SetLinuxDistro(const std::string& distro) { std::string trimmed_distro; TrimWhitespaceASCII(distro, TRIM_ALL, &trimmed_distro); strlcpy(g_linux_distro, trimmed_distro.c_str(), kDistroSize); } bool GetThreadsForProcess(pid_t pid, std::vector* tids) { // 25 > strlen("/proc//task") + strlen(std::to_string(INT_MAX)) + 1 = 22 char buf[25]; strings::SafeSPrintf(buf, "/proc/%d/task", pid); DirReaderPosix dir_reader(buf); if (!dir_reader.IsValid()) { DLOG(WARNING) << "Cannot open " << buf; return false; } while (dir_reader.Next()) { pid_t tid; if (StringToInt(dir_reader.name(), &tid)) tids->push_back(tid); } return true; } pid_t FindThreadIDWithSyscall(pid_t pid, const std::string& expected_data, bool* syscall_supported) { if (syscall_supported) *syscall_supported = false; std::vector tids; if (!GetThreadsForProcess(pid, &tids)) return -1; std::vector syscall_data(expected_data.size()); for (pid_t tid : tids) { char buf[256]; snprintf(buf, sizeof(buf), "/proc/%d/task/%d/syscall", pid, tid); ScopedFD fd(open(buf, O_RDONLY)); if (!fd.is_valid()) continue; *syscall_supported = true; if (!ReadFromFD(fd.get(), syscall_data.data(), syscall_data.size())) continue; if (0 == strncmp(expected_data.c_str(), syscall_data.data(), expected_data.size())) { return tid; } } return -1; } pid_t FindThreadID(pid_t pid, pid_t ns_tid, bool* ns_pid_supported) { *ns_pid_supported = false; std::vector tids; if (!GetThreadsForProcess(pid, &tids)) return -1; for (pid_t tid : tids) { char buf[256]; snprintf(buf, sizeof(buf), "/proc/%d/task/%d/status", pid, tid); std::string status; if (!ReadFileToString(FilePath(buf), &status)) return -1; StringTokenizer tokenizer(status, "\n"); while (tokenizer.GetNext()) { StringPiece value_str(tokenizer.token_piece()); if (!StartsWith(value_str, "NSpid")) continue; *ns_pid_supported = true; std::vector split_value_str = SplitStringPiece( value_str, "\t", TRIM_WHITESPACE, SPLIT_WANT_NONEMPTY); DCHECK_GE(split_value_str.size(), 2u); int value; // The last value in the list is the PID in the namespace. if (StringToInt(split_value_str.back(), &value) && value == ns_tid) { // The second value in the list is the real PID. if (StringToInt(split_value_str[1], &value)) return value; } break; } } return -1; } } // namespace base