blob: 1f3ae498bc28213ec443f8f937aea5b107abc184 [file] [log] [blame]
// 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <memory>
#include <vector>
#include "base/command_line.h"
#include "base/files/file_util.h"
#include "base/memory/singleton.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 "base/synchronization/lock.h"
#include "build_config.h"
namespace {
// Not needed for OS_CHROMEOS.
#if defined(OS_LINUX)
enum LinuxDistroState {
STATE_DID_NOT_CHECK = 0,
STATE_CHECK_STARTED = 1,
STATE_CHECK_FINISHED = 2,
};
// Helper class for GetLinuxDistro().
class LinuxDistroHelper {
public:
// Retrieves the Singleton.
static LinuxDistroHelper* GetInstance() {
return base::Singleton<LinuxDistroHelper>::get();
}
// The simple state machine goes from:
// STATE_DID_NOT_CHECK -> STATE_CHECK_STARTED -> STATE_CHECK_FINISHED.
LinuxDistroHelper() : state_(STATE_DID_NOT_CHECK) {}
~LinuxDistroHelper() = default;
// Retrieve the current state, if we're in STATE_DID_NOT_CHECK,
// we automatically move to STATE_CHECK_STARTED so nobody else will
// do the check.
LinuxDistroState State() {
base::AutoLock scoped_lock(lock_);
if (STATE_DID_NOT_CHECK == state_) {
state_ = STATE_CHECK_STARTED;
return STATE_DID_NOT_CHECK;
}
return state_;
}
// Indicate the check finished, move to STATE_CHECK_FINISHED.
void CheckFinished() {
base::AutoLock scoped_lock(lock_);
DCHECK_EQ(STATE_CHECK_STARTED, state_);
state_ = STATE_CHECK_FINISHED;
}
private:
base::Lock lock_;
LinuxDistroState state_;
};
#endif // if defined(OS_LINUX)
bool GetTasksForProcess(pid_t pid, std::vector<pid_t>* tids) {
char buf[256];
snprintf(buf, sizeof(buf), "/proc/%d/task", pid);
DIR* task = opendir(buf);
if (!task) {
DLOG(WARNING) << "Cannot open " << buf;
return false;
}
struct dirent* dent;
while ((dent = readdir(task))) {
char* endptr;
const unsigned long int tid_ul = strtoul(dent->d_name, &endptr, 10);
if (tid_ul == ULONG_MAX || *endptr)
continue;
tids->push_back(tid_ul);
}
closedir(task);
return true;
}
} // namespace
namespace base {
// Account for the terminating null character.
static const int kDistroSize = 128 + 1;
// 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] = "Unknown";
std::string GetLinuxDistro() {
LinuxDistroHelper* distro_state_singleton = LinuxDistroHelper::GetInstance();
LinuxDistroState state = distro_state_singleton->State();
if (STATE_CHECK_FINISHED == state)
return g_linux_distro;
if (STATE_CHECK_STARTED == state)
return "Unknown"; // Don't wait for other thread to finish.
DCHECK_EQ(state, STATE_DID_NOT_CHECK);
// 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
// lsb_release again.
std::vector<std::string> argv;
argv.push_back("lsb_release");
argv.push_back("-d");
std::string output;
GetAppOutput(CommandLine(argv), &output);
if (output.length() > 0) {
// lsb_release -d should return: Description:<tab>Distro Info
const char field[] = "Description:\t";
if (output.compare(0, strlen(field), field) == 0) {
SetLinuxDistro(output.substr(strlen(field)));
}
}
distro_state_singleton->CheckFinished();
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);
}
pid_t FindThreadIDWithSyscall(pid_t pid, const std::string& expected_data,
bool* syscall_supported) {
if (syscall_supported != nullptr)
*syscall_supported = false;
std::vector<pid_t> tids;
if (!GetTasksForProcess(pid, &tids))
return -1;
std::unique_ptr<char[]> syscall_data(new char[expected_data.length()]);
for (pid_t tid : tids) {
char buf[256];
snprintf(buf, sizeof(buf), "/proc/%d/task/%d/syscall", pid, tid);
int fd = open(buf, O_RDONLY);
if (fd < 0)
continue;
if (syscall_supported != nullptr)
*syscall_supported = true;
bool read_ret = ReadFromFD(fd, syscall_data.get(), expected_data.length());
close(fd);
if (!read_ret)
continue;
if (0 == strncmp(expected_data.c_str(), syscall_data.get(),
expected_data.length())) {
return tid;
}
}
return -1;
}
pid_t FindThreadID(pid_t pid, pid_t ns_tid, bool* ns_pid_supported) {
if (ns_pid_supported)
*ns_pid_supported = false;
std::vector<pid_t> tids;
if (!GetTasksForProcess(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 (!value_str.starts_with("NSpid"))
continue;
if (ns_pid_supported)
*ns_pid_supported = true;
std::vector<StringPiece> 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