blob: 49df773ca11a2fd31108c67573ef185644c4f69f [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 <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <vector>
#include "base/command_line.h"
#include "base/file_util.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/singleton.h"
#include "base/path_service.h"
#include "base/process_util.h"
#include "base/string_util.h"
#include "base/synchronization/lock.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 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() {}
// 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)
// expected prefix of the target of the /proc/self/fd/%d link for a socket
const char kSocketLinkPrefix[] = "socket:[";
// Parse a symlink in /proc/pid/fd/$x and return the inode number of the
// socket.
// inode_out: (output) set to the inode number on success
// path: e.g. /proc/1234/fd/5 (must be a UNIX domain socket descriptor)
// log: if true, log messages about failure details
bool ProcPathGetInode(ino_t* inode_out, const char* path, bool log = false) {
DCHECK(inode_out);
DCHECK(path);
char buf[256];
const ssize_t n = readlink(path, buf, sizeof(buf) - 1);
if (n == -1) {
if (log) {
DLOG(WARNING) << "Failed to read the inode number for a socket from /proc"
"(" << errno << ")";
}
return false;
}
buf[n] = 0;
if (memcmp(kSocketLinkPrefix, buf, sizeof(kSocketLinkPrefix) - 1)) {
if (log) {
DLOG(WARNING) << "The descriptor passed from the crashing process wasn't "
" a UNIX domain socket.";
}
return false;
}
char* endptr;
const unsigned long long int inode_ul =
strtoull(buf + sizeof(kSocketLinkPrefix) - 1, &endptr, 10);
if (*endptr != ']')
return false;
if (inode_ul == ULLONG_MAX) {
if (log) {
DLOG(WARNING) << "Failed to parse a socket's inode number: the number "
"was too large. Please report this bug: " << buf;
}
return false;
}
*inode_out = inode_ul;
return true;
}
} // namespace
namespace base {
const char kFindInodeSwitch[] = "--find-inode";
// 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] =
#if defined(OS_CHROMEOS)
"CrOS";
#elif defined(OS_ANDROID)
"Android";
#else // if defined(OS_LINUX)
"Unknown";
#endif
std::string GetLinuxDistro() {
#if defined(OS_CHROMEOS) || defined(OS_ANDROID)
return g_linux_distro;
#elif defined(OS_LINUX)
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;
base::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;
#else
NOTIMPLEMENTED();
return "Unknown";
#endif
}
void SetLinuxDistro(const std::string& distro) {
std::string trimmed_distro;
TrimWhitespaceASCII(distro, TRIM_ALL, &trimmed_distro);
base::strlcpy(g_linux_distro, trimmed_distro.c_str(), kDistroSize);
}
bool FileDescriptorGetInode(ino_t* inode_out, int fd) {
DCHECK(inode_out);
struct stat buf;
if (fstat(fd, &buf) < 0)
return false;
if (!S_ISSOCK(buf.st_mode))
return false;
*inode_out = buf.st_ino;
return true;
}
bool FindProcessHoldingSocket(pid_t* pid_out, ino_t socket_inode) {
DCHECK(pid_out);
bool already_found = false;
DIR* proc = opendir("/proc");
if (!proc) {
DLOG(WARNING) << "Cannot open /proc";
return false;
}
std::vector<pid_t> pids;
struct dirent* dent;
while ((dent = readdir(proc))) {
char* endptr;
const unsigned long int pid_ul = strtoul(dent->d_name, &endptr, 10);
if (pid_ul == ULONG_MAX || *endptr)
continue;
pids.push_back(pid_ul);
}
closedir(proc);
for (std::vector<pid_t>::const_iterator
i = pids.begin(); i != pids.end(); ++i) {
const pid_t current_pid = *i;
char buf[256];
snprintf(buf, sizeof(buf), "/proc/%d/fd", current_pid);
DIR* fd = opendir(buf);
if (!fd)
continue;
while ((dent = readdir(fd))) {
if (snprintf(buf, sizeof(buf), "/proc/%d/fd/%s", current_pid,
dent->d_name) >= static_cast<int>(sizeof(buf))) {
continue;
}
ino_t fd_inode;
if (ProcPathGetInode(&fd_inode, buf)) {
if (fd_inode == socket_inode) {
if (already_found) {
closedir(fd);
return false;
}
already_found = true;
*pid_out = current_pid;
break;
}
}
}
closedir(fd);
}
return already_found;
}
pid_t FindThreadIDWithSyscall(pid_t pid, const std::string& expected_data,
bool* syscall_supported) {
char buf[256];
snprintf(buf, sizeof(buf), "/proc/%d/task", pid);
if (syscall_supported != NULL)
*syscall_supported = false;
DIR* task = opendir(buf);
if (!task) {
DLOG(WARNING) << "Cannot open " << buf;
return -1;
}
std::vector<pid_t> tids;
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);
scoped_array<char> syscall_data(new char[expected_data.length()]);
for (std::vector<pid_t>::const_iterator
i = tids.begin(); i != tids.end(); ++i) {
const pid_t current_tid = *i;
snprintf(buf, sizeof(buf), "/proc/%d/task/%d/syscall", pid, current_tid);
int fd = open(buf, O_RDONLY);
if (fd < 0)
continue;
if (syscall_supported != NULL)
*syscall_supported = true;
bool read_ret =
file_util::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 current_tid;
}
}
return -1;
}
} // namespace base