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|
// 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <iterator>
#include <limits>
#include <set>
#include "base/allocator/type_profiler_control.h"
#include "base/command_line.h"
#include "base/compiler_specific.h"
#include "base/debug/debugger.h"
#include "base/debug/stack_trace.h"
#include "base/file_util.h"
#include "base/files/dir_reader_posix.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/posix/eintr_wrapper.h"
#include "base/process_util.h"
#include "base/stringprintf.h"
#include "base/synchronization/waitable_event.h"
#include "base/third_party/dynamic_annotations/dynamic_annotations.h"
#include "base/threading/platform_thread.h"
#include "base/threading/thread_restrictions.h"
#if defined(OS_CHROMEOS)
#include <sys/ioctl.h>
#endif
#if defined(OS_FREEBSD)
#include <sys/event.h>
#include <sys/ucontext.h>
#endif
#if defined(OS_MACOSX)
#include <crt_externs.h>
#include <sys/event.h>
#else
extern char** environ;
#endif
namespace base {
namespace {
// Get the process's "environment" (i.e. the thing that setenv/getenv
// work with).
char** GetEnvironment() {
#if defined(OS_MACOSX)
return *_NSGetEnviron();
#else
return environ;
#endif
}
// Set the process's "environment" (i.e. the thing that setenv/getenv
// work with).
void SetEnvironment(char** env) {
#if defined(OS_MACOSX)
*_NSGetEnviron() = env;
#else
environ = env;
#endif
}
int WaitpidWithTimeout(ProcessHandle handle, int64 wait_milliseconds,
bool* success) {
// This POSIX version of this function only guarantees that we wait no less
// than |wait_milliseconds| for the process to exit. The child process may
// exit sometime before the timeout has ended but we may still block for up
// to 256 milliseconds after the fact.
//
// waitpid() has no direct support on POSIX for specifying a timeout, you can
// either ask it to block indefinitely or return immediately (WNOHANG).
// When a child process terminates a SIGCHLD signal is sent to the parent.
// Catching this signal would involve installing a signal handler which may
// affect other parts of the application and would be difficult to debug.
//
// Our strategy is to call waitpid() once up front to check if the process
// has already exited, otherwise to loop for wait_milliseconds, sleeping for
// at most 256 milliseconds each time using usleep() and then calling
// waitpid(). The amount of time we sleep starts out at 1 milliseconds, and
// we double it every 4 sleep cycles.
//
// usleep() is speced to exit if a signal is received for which a handler
// has been installed. This means that when a SIGCHLD is sent, it will exit
// depending on behavior external to this function.
//
// This function is used primarily for unit tests, if we want to use it in
// the application itself it would probably be best to examine other routes.
int status = -1;
pid_t ret_pid = HANDLE_EINTR(waitpid(handle, &status, WNOHANG));
static const int64 kMaxSleepInMicroseconds = 1 << 18; // ~256 milliseconds.
int64 max_sleep_time_usecs = 1 << 10; // ~1 milliseconds.
int64 double_sleep_time = 0;
// If the process hasn't exited yet, then sleep and try again.
TimeTicks wakeup_time = TimeTicks::Now() +
TimeDelta::FromMilliseconds(wait_milliseconds);
while (ret_pid == 0) {
TimeTicks now = TimeTicks::Now();
if (now > wakeup_time)
break;
// Guaranteed to be non-negative!
int64 sleep_time_usecs = (wakeup_time - now).InMicroseconds();
// Sleep for a bit while we wait for the process to finish.
if (sleep_time_usecs > max_sleep_time_usecs)
sleep_time_usecs = max_sleep_time_usecs;
// usleep() will return 0 and set errno to EINTR on receipt of a signal
// such as SIGCHLD.
usleep(sleep_time_usecs);
ret_pid = HANDLE_EINTR(waitpid(handle, &status, WNOHANG));
if ((max_sleep_time_usecs < kMaxSleepInMicroseconds) &&
(double_sleep_time++ % 4 == 0)) {
max_sleep_time_usecs *= 2;
}
}
if (success)
*success = (ret_pid != -1);
return status;
}
#if !defined(OS_LINUX) || \
(!defined(__i386__) && !defined(__x86_64__) && !defined(__arm__))
void ResetChildSignalHandlersToDefaults() {
// The previous signal handlers are likely to be meaningless in the child's
// context so we reset them to the defaults for now. http://crbug.com/44953
// These signal handlers are set up at least in browser_main_posix.cc:
// BrowserMainPartsPosix::PreEarlyInitialization and stack_trace_posix.cc:
// EnableInProcessStackDumping.
signal(SIGHUP, SIG_DFL);
signal(SIGINT, SIG_DFL);
signal(SIGILL, SIG_DFL);
signal(SIGABRT, SIG_DFL);
signal(SIGFPE, SIG_DFL);
signal(SIGBUS, SIG_DFL);
signal(SIGSEGV, SIG_DFL);
signal(SIGSYS, SIG_DFL);
signal(SIGTERM, SIG_DFL);
}
#else
// TODO(jln): remove the Linux special case once kernels are fixed.
// Internally the kernel makes sigset_t an array of long large enough to have
// one bit per signal.
typedef uint64_t kernel_sigset_t;
// This is what struct sigaction looks like to the kernel at least on X86 and
// ARM. MIPS, for instance, is very different.
struct kernel_sigaction {
void* k_sa_handler; // For this usage it only needs to be a generic pointer.
unsigned long k_sa_flags;
void* k_sa_restorer; // For this usage it only needs to be a generic pointer.
kernel_sigset_t k_sa_mask;
};
// glibc's sigaction() will prevent access to sa_restorer, so we need to roll
// our own.
int sys_rt_sigaction(int sig, const struct kernel_sigaction* act,
struct kernel_sigaction* oact) {
return syscall(SYS_rt_sigaction, sig, act, oact, sizeof(kernel_sigset_t));
}
// This function is intended to be used in between fork() and execve() and will
// reset all signal handlers to the default.
// The motivation for going through all of them is that sa_restorer can leak
// from parents and help defeat ASLR on buggy kernels. We reset it to NULL.
// See crbug.com/177956.
void ResetChildSignalHandlersToDefaults(void) {
for (int signum = 1; ; ++signum) {
struct kernel_sigaction act = {0};
int sigaction_get_ret = sys_rt_sigaction(signum, NULL, &act);
if (sigaction_get_ret && errno == EINVAL) {
#if !defined(NDEBUG)
// Linux supports 32 real-time signals from 33 to 64.
// If the number of signals in the Linux kernel changes, someone should
// look at this code.
const int kNumberOfSignals = 64;
RAW_CHECK(signum == kNumberOfSignals + 1);
#endif // !defined(NDEBUG)
break;
}
// All other failures are fatal.
if (sigaction_get_ret) {
RAW_LOG(FATAL, "sigaction (get) failed.");
}
// The kernel won't allow to re-set SIGKILL or SIGSTOP.
if (signum != SIGSTOP && signum != SIGKILL) {
act.k_sa_handler = reinterpret_cast<void*>(SIG_DFL);
act.k_sa_restorer = NULL;
if (sys_rt_sigaction(signum, &act, NULL)) {
RAW_LOG(FATAL, "sigaction (set) failed.");
}
}
#if !defined(NDEBUG)
// Now ask the kernel again and check that no restorer will leak.
if (sys_rt_sigaction(signum, NULL, &act) || act.k_sa_restorer) {
RAW_LOG(FATAL, "Cound not fix sa_restorer.");
}
#endif // !defined(NDEBUG)
}
}
#endif // !defined(OS_LINUX) ||
// (!defined(__i386__) && !defined(__x86_64__) && !defined(__arm__))
TerminationStatus GetTerminationStatusImpl(ProcessHandle handle,
bool can_block,
int* exit_code) {
int status = 0;
const pid_t result = HANDLE_EINTR(waitpid(handle, &status,
can_block ? 0 : WNOHANG));
if (result == -1) {
DPLOG(ERROR) << "waitpid(" << handle << ")";
if (exit_code)
*exit_code = 0;
return TERMINATION_STATUS_NORMAL_TERMINATION;
} else if (result == 0) {
// the child hasn't exited yet.
if (exit_code)
*exit_code = 0;
return TERMINATION_STATUS_STILL_RUNNING;
}
if (exit_code)
*exit_code = status;
if (WIFSIGNALED(status)) {
switch (WTERMSIG(status)) {
case SIGABRT:
case SIGBUS:
case SIGFPE:
case SIGILL:
case SIGSEGV:
return TERMINATION_STATUS_PROCESS_CRASHED;
case SIGINT:
case SIGKILL:
case SIGTERM:
return TERMINATION_STATUS_PROCESS_WAS_KILLED;
default:
break;
}
}
if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
return TERMINATION_STATUS_ABNORMAL_TERMINATION;
return TERMINATION_STATUS_NORMAL_TERMINATION;
}
} // anonymous namespace
ProcessId GetCurrentProcId() {
return getpid();
}
ProcessHandle GetCurrentProcessHandle() {
return GetCurrentProcId();
}
bool OpenProcessHandle(ProcessId pid, ProcessHandle* handle) {
// On Posix platforms, process handles are the same as PIDs, so we
// don't need to do anything.
*handle = pid;
return true;
}
bool OpenPrivilegedProcessHandle(ProcessId pid, ProcessHandle* handle) {
// On POSIX permissions are checked for each operation on process,
// not when opening a "handle".
return OpenProcessHandle(pid, handle);
}
bool OpenProcessHandleWithAccess(ProcessId pid,
uint32 access_flags,
ProcessHandle* handle) {
// On POSIX permissions are checked for each operation on process,
// not when opening a "handle".
return OpenProcessHandle(pid, handle);
}
void CloseProcessHandle(ProcessHandle process) {
// See OpenProcessHandle, nothing to do.
return;
}
ProcessId GetProcId(ProcessHandle process) {
return process;
}
// Attempts to kill the process identified by the given process
// entry structure. Ignores specified exit_code; posix can't force that.
// Returns true if this is successful, false otherwise.
bool KillProcess(ProcessHandle process_id, int exit_code, bool wait) {
DCHECK_GT(process_id, 1) << " tried to kill invalid process_id";
if (process_id <= 1)
return false;
bool result = kill(process_id, SIGTERM) == 0;
if (result && wait) {
int tries = 60;
if (RunningOnValgrind()) {
// Wait for some extra time when running under Valgrind since the child
// processes may take some time doing leak checking.
tries *= 2;
}
unsigned sleep_ms = 4;
// The process may not end immediately due to pending I/O
bool exited = false;
while (tries-- > 0) {
pid_t pid = HANDLE_EINTR(waitpid(process_id, NULL, WNOHANG));
if (pid == process_id) {
exited = true;
break;
}
if (pid == -1) {
if (errno == ECHILD) {
// The wait may fail with ECHILD if another process also waited for
// the same pid, causing the process state to get cleaned up.
exited = true;
break;
}
DPLOG(ERROR) << "Error waiting for process " << process_id;
}
usleep(sleep_ms * 1000);
const unsigned kMaxSleepMs = 1000;
if (sleep_ms < kMaxSleepMs)
sleep_ms *= 2;
}
// If we're waiting and the child hasn't died by now, force it
// with a SIGKILL.
if (!exited)
result = kill(process_id, SIGKILL) == 0;
}
if (!result)
DPLOG(ERROR) << "Unable to terminate process " << process_id;
return result;
}
bool KillProcessGroup(ProcessHandle process_group_id) {
bool result = kill(-1 * process_group_id, SIGKILL) == 0;
if (!result)
DPLOG(ERROR) << "Unable to terminate process group " << process_group_id;
return result;
}
// A class to handle auto-closing of DIR*'s.
class ScopedDIRClose {
public:
inline void operator()(DIR* x) const {
if (x) {
closedir(x);
}
}
};
typedef scoped_ptr_malloc<DIR, ScopedDIRClose> ScopedDIR;
#if defined(OS_LINUX)
static const rlim_t kSystemDefaultMaxFds = 8192;
static const char kFDDir[] = "/proc/self/fd";
#elif defined(OS_MACOSX)
static const rlim_t kSystemDefaultMaxFds = 256;
static const char kFDDir[] = "/dev/fd";
#elif defined(OS_SOLARIS)
static const rlim_t kSystemDefaultMaxFds = 8192;
static const char kFDDir[] = "/dev/fd";
#elif defined(OS_FREEBSD)
static const rlim_t kSystemDefaultMaxFds = 8192;
static const char kFDDir[] = "/dev/fd";
#elif defined(OS_OPENBSD)
static const rlim_t kSystemDefaultMaxFds = 256;
static const char kFDDir[] = "/dev/fd";
#elif defined(OS_ANDROID)
static const rlim_t kSystemDefaultMaxFds = 1024;
static const char kFDDir[] = "/proc/self/fd";
#endif
size_t GetMaxFds() {
rlim_t max_fds;
struct rlimit nofile;
if (getrlimit(RLIMIT_NOFILE, &nofile)) {
// getrlimit failed. Take a best guess.
max_fds = kSystemDefaultMaxFds;
RAW_LOG(ERROR, "getrlimit(RLIMIT_NOFILE) failed");
} else {
max_fds = nofile.rlim_cur;
}
if (max_fds > INT_MAX)
max_fds = INT_MAX;
return static_cast<size_t>(max_fds);
}
void CloseSuperfluousFds(const base::InjectiveMultimap& saved_mapping) {
// DANGER: no calls to malloc are allowed from now on:
// http://crbug.com/36678
// Get the maximum number of FDs possible.
size_t max_fds = GetMaxFds();
DirReaderPosix fd_dir(kFDDir);
if (!fd_dir.IsValid()) {
// Fallback case: Try every possible fd.
for (size_t i = 0; i < max_fds; ++i) {
const int fd = static_cast<int>(i);
if (fd == STDIN_FILENO || fd == STDOUT_FILENO || fd == STDERR_FILENO)
continue;
InjectiveMultimap::const_iterator j;
for (j = saved_mapping.begin(); j != saved_mapping.end(); j++) {
if (fd == j->dest)
break;
}
if (j != saved_mapping.end())
continue;
// Since we're just trying to close anything we can find,
// ignore any error return values of close().
ignore_result(HANDLE_EINTR(close(fd)));
}
return;
}
const int dir_fd = fd_dir.fd();
for ( ; fd_dir.Next(); ) {
// Skip . and .. entries.
if (fd_dir.name()[0] == '.')
continue;
char *endptr;
errno = 0;
const long int fd = strtol(fd_dir.name(), &endptr, 10);
if (fd_dir.name()[0] == 0 || *endptr || fd < 0 || errno)
continue;
if (fd == STDIN_FILENO || fd == STDOUT_FILENO || fd == STDERR_FILENO)
continue;
InjectiveMultimap::const_iterator i;
for (i = saved_mapping.begin(); i != saved_mapping.end(); i++) {
if (fd == i->dest)
break;
}
if (i != saved_mapping.end())
continue;
if (fd == dir_fd)
continue;
// When running under Valgrind, Valgrind opens several FDs for its
// own use and will complain if we try to close them. All of
// these FDs are >= |max_fds|, so we can check against that here
// before closing. See https://bugs.kde.org/show_bug.cgi?id=191758
if (fd < static_cast<int>(max_fds)) {
int ret = HANDLE_EINTR(close(fd));
DPCHECK(ret == 0);
}
}
}
char** AlterEnvironment(const EnvironmentVector& changes,
const char* const* const env) {
unsigned count = 0;
unsigned size = 0;
// First assume that all of the current environment will be included.
for (unsigned i = 0; env[i]; i++) {
const char *const pair = env[i];
count++;
size += strlen(pair) + 1 /* terminating NUL */;
}
for (EnvironmentVector::const_iterator j = changes.begin();
j != changes.end();
++j) {
bool found = false;
const char *pair;
for (unsigned i = 0; env[i]; i++) {
pair = env[i];
const char *const equals = strchr(pair, '=');
if (!equals)
continue;
const unsigned keylen = equals - pair;
if (keylen == j->first.size() &&
memcmp(pair, j->first.data(), keylen) == 0) {
found = true;
break;
}
}
// if found, we'll either be deleting or replacing this element.
if (found) {
count--;
size -= strlen(pair) + 1;
if (j->second.size())
found = false;
}
// if !found, then we have a new element to add.
if (!found && !j->second.empty()) {
count++;
size += j->first.size() + 1 /* '=' */ + j->second.size() + 1 /* NUL */;
}
}
count++; // for the final NULL
uint8_t *buffer = new uint8_t[sizeof(char*) * count + size];
char **const ret = reinterpret_cast<char**>(buffer);
unsigned k = 0;
char *scratch = reinterpret_cast<char*>(buffer + sizeof(char*) * count);
for (unsigned i = 0; env[i]; i++) {
const char *const pair = env[i];
const char *const equals = strchr(pair, '=');
if (!equals) {
const unsigned len = strlen(pair);
ret[k++] = scratch;
memcpy(scratch, pair, len + 1);
scratch += len + 1;
continue;
}
const unsigned keylen = equals - pair;
bool handled = false;
for (EnvironmentVector::const_iterator
j = changes.begin(); j != changes.end(); j++) {
if (j->first.size() == keylen &&
memcmp(j->first.data(), pair, keylen) == 0) {
if (!j->second.empty()) {
ret[k++] = scratch;
memcpy(scratch, pair, keylen + 1);
scratch += keylen + 1;
memcpy(scratch, j->second.c_str(), j->second.size() + 1);
scratch += j->second.size() + 1;
}
handled = true;
break;
}
}
if (!handled) {
const unsigned len = strlen(pair);
ret[k++] = scratch;
memcpy(scratch, pair, len + 1);
scratch += len + 1;
}
}
// Now handle new elements
for (EnvironmentVector::const_iterator
j = changes.begin(); j != changes.end(); j++) {
if (j->second.empty())
continue;
bool found = false;
for (unsigned i = 0; env[i]; i++) {
const char *const pair = env[i];
const char *const equals = strchr(pair, '=');
if (!equals)
continue;
const unsigned keylen = equals - pair;
if (keylen == j->first.size() &&
memcmp(pair, j->first.data(), keylen) == 0) {
found = true;
break;
}
}
if (!found) {
ret[k++] = scratch;
memcpy(scratch, j->first.data(), j->first.size());
scratch += j->first.size();
*scratch++ = '=';
memcpy(scratch, j->second.c_str(), j->second.size() + 1);
scratch += j->second.size() + 1;
}
}
ret[k] = NULL;
return ret;
}
bool LaunchProcess(const std::vector<std::string>& argv,
const LaunchOptions& options,
ProcessHandle* process_handle) {
size_t fd_shuffle_size = 0;
if (options.fds_to_remap) {
fd_shuffle_size = options.fds_to_remap->size();
}
InjectiveMultimap fd_shuffle1;
InjectiveMultimap fd_shuffle2;
fd_shuffle1.reserve(fd_shuffle_size);
fd_shuffle2.reserve(fd_shuffle_size);
scoped_ptr<char*[]> argv_cstr(new char*[argv.size() + 1]);
scoped_ptr<char*[]> new_environ;
if (options.environ)
new_environ.reset(AlterEnvironment(*options.environ, GetEnvironment()));
pid_t pid;
#if defined(OS_LINUX)
if (options.clone_flags) {
pid = syscall(__NR_clone, options.clone_flags, 0, 0, 0);
} else
#endif
{
pid = fork();
}
if (pid < 0) {
DPLOG(ERROR) << "fork";
return false;
} else if (pid == 0) {
// Child process
// DANGER: fork() rule: in the child, if you don't end up doing exec*(),
// you call _exit() instead of exit(). This is because _exit() does not
// call any previously-registered (in the parent) exit handlers, which
// might do things like block waiting for threads that don't even exist
// in the child.
// If a child process uses the readline library, the process block forever.
// In BSD like OSes including OS X it is safe to assign /dev/null as stdin.
// See http://crbug.com/56596.
int null_fd = HANDLE_EINTR(open("/dev/null", O_RDONLY));
if (null_fd < 0) {
RAW_LOG(ERROR, "Failed to open /dev/null");
_exit(127);
}
file_util::ScopedFD null_fd_closer(&null_fd);
int new_fd = HANDLE_EINTR(dup2(null_fd, STDIN_FILENO));
if (new_fd != STDIN_FILENO) {
RAW_LOG(ERROR, "Failed to dup /dev/null for stdin");
_exit(127);
}
if (options.new_process_group) {
// Instead of inheriting the process group ID of the parent, the child
// starts off a new process group with pgid equal to its process ID.
if (setpgid(0, 0) < 0) {
RAW_LOG(ERROR, "setpgid failed");
_exit(127);
}
}
// Stop type-profiler.
// The profiler should be stopped between fork and exec since it inserts
// locks at new/delete expressions. See http://crbug.com/36678.
base::type_profiler::Controller::Stop();
if (options.maximize_rlimits) {
// Some resource limits need to be maximal in this child.
std::set<int>::const_iterator resource;
for (resource = options.maximize_rlimits->begin();
resource != options.maximize_rlimits->end();
++resource) {
struct rlimit limit;
if (getrlimit(*resource, &limit) < 0) {
RAW_LOG(WARNING, "getrlimit failed");
} else if (limit.rlim_cur < limit.rlim_max) {
limit.rlim_cur = limit.rlim_max;
if (setrlimit(*resource, &limit) < 0) {
RAW_LOG(WARNING, "setrlimit failed");
}
}
}
}
#if defined(OS_MACOSX)
RestoreDefaultExceptionHandler();
#endif // defined(OS_MACOSX)
ResetChildSignalHandlersToDefaults();
#if 0
// When debugging it can be helpful to check that we really aren't making
// any hidden calls to malloc.
void *malloc_thunk =
reinterpret_cast<void*>(reinterpret_cast<intptr_t>(malloc) & ~4095);
mprotect(malloc_thunk, 4096, PROT_READ | PROT_WRITE | PROT_EXEC);
memset(reinterpret_cast<void*>(malloc), 0xff, 8);
#endif // 0
// DANGER: no calls to malloc are allowed from now on:
// http://crbug.com/36678
#if defined(OS_CHROMEOS)
if (options.ctrl_terminal_fd >= 0) {
// Set process' controlling terminal.
if (HANDLE_EINTR(setsid()) != -1) {
if (HANDLE_EINTR(
ioctl(options.ctrl_terminal_fd, TIOCSCTTY, NULL)) == -1) {
RAW_LOG(WARNING, "ioctl(TIOCSCTTY), ctrl terminal not set");
}
} else {
RAW_LOG(WARNING, "setsid failed, ctrl terminal not set");
}
}
#endif // defined(OS_CHROMEOS)
if (options.fds_to_remap) {
for (FileHandleMappingVector::const_iterator
it = options.fds_to_remap->begin();
it != options.fds_to_remap->end(); ++it) {
fd_shuffle1.push_back(InjectionArc(it->first, it->second, false));
fd_shuffle2.push_back(InjectionArc(it->first, it->second, false));
}
}
if (options.environ)
SetEnvironment(new_environ.get());
// fd_shuffle1 is mutated by this call because it cannot malloc.
if (!ShuffleFileDescriptors(&fd_shuffle1))
_exit(127);
CloseSuperfluousFds(fd_shuffle2);
for (size_t i = 0; i < argv.size(); i++)
argv_cstr[i] = const_cast<char*>(argv[i].c_str());
argv_cstr[argv.size()] = NULL;
execvp(argv_cstr[0], argv_cstr.get());
RAW_LOG(ERROR, "LaunchProcess: failed to execvp:");
RAW_LOG(ERROR, argv_cstr[0]);
_exit(127);
} else {
// Parent process
if (options.wait) {
// While this isn't strictly disk IO, waiting for another process to
// finish is the sort of thing ThreadRestrictions is trying to prevent.
base::ThreadRestrictions::AssertIOAllowed();
pid_t ret = HANDLE_EINTR(waitpid(pid, 0, 0));
DPCHECK(ret > 0);
}
if (process_handle)
*process_handle = pid;
}
return true;
}
bool LaunchProcess(const CommandLine& cmdline,
const LaunchOptions& options,
ProcessHandle* process_handle) {
return LaunchProcess(cmdline.argv(), options, process_handle);
}
void RaiseProcessToHighPriority() {
// On POSIX, we don't actually do anything here. We could try to nice() or
// setpriority() or sched_getscheduler, but these all require extra rights.
}
TerminationStatus GetTerminationStatus(ProcessHandle handle, int* exit_code) {
return GetTerminationStatusImpl(handle, false /* can_block */, exit_code);
}
TerminationStatus WaitForTerminationStatus(ProcessHandle handle,
int* exit_code) {
return GetTerminationStatusImpl(handle, true /* can_block */, exit_code);
}
bool WaitForExitCode(ProcessHandle handle, int* exit_code) {
int status;
if (HANDLE_EINTR(waitpid(handle, &status, 0)) == -1) {
NOTREACHED();
return false;
}
if (WIFEXITED(status)) {
*exit_code = WEXITSTATUS(status);
return true;
}
// If it didn't exit cleanly, it must have been signaled.
DCHECK(WIFSIGNALED(status));
return false;
}
bool WaitForExitCodeWithTimeout(ProcessHandle handle, int* exit_code,
base::TimeDelta timeout) {
bool waitpid_success = false;
int status = WaitpidWithTimeout(handle, timeout.InMilliseconds(),
&waitpid_success);
if (status == -1)
return false;
if (!waitpid_success)
return false;
if (WIFSIGNALED(status)) {
*exit_code = -1;
return true;
}
if (WIFEXITED(status)) {
*exit_code = WEXITSTATUS(status);
return true;
}
return false;
}
#if defined(OS_MACOSX)
// Using kqueue on Mac so that we can wait on non-child processes.
// We can't use kqueues on child processes because we need to reap
// our own children using wait.
static bool WaitForSingleNonChildProcess(ProcessHandle handle,
base::TimeDelta wait) {
DCHECK_GT(handle, 0);
DCHECK(wait.InMilliseconds() == base::kNoTimeout || wait > base::TimeDelta());
int kq = kqueue();
if (kq == -1) {
DPLOG(ERROR) << "kqueue";
return false;
}
file_util::ScopedFD kq_closer(&kq);
struct kevent change = {0};
EV_SET(&change, handle, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL);
int result = HANDLE_EINTR(kevent(kq, &change, 1, NULL, 0, NULL));
if (result == -1) {
if (errno == ESRCH) {
// If the process wasn't found, it must be dead.
return true;
}
DPLOG(ERROR) << "kevent (setup " << handle << ")";
return false;
}
// Keep track of the elapsed time to be able to restart kevent if it's
// interrupted.
bool wait_forever = wait.InMilliseconds() == base::kNoTimeout;
base::TimeDelta remaining_delta;
base::TimeTicks deadline;
if (!wait_forever) {
remaining_delta = wait;
deadline = base::TimeTicks::Now() + remaining_delta;
}
result = -1;
struct kevent event = {0};
while (wait_forever || remaining_delta > base::TimeDelta()) {
struct timespec remaining_timespec;
struct timespec* remaining_timespec_ptr;
if (wait_forever) {
remaining_timespec_ptr = NULL;
} else {
remaining_timespec = remaining_delta.ToTimeSpec();
remaining_timespec_ptr = &remaining_timespec;
}
result = kevent(kq, NULL, 0, &event, 1, remaining_timespec_ptr);
if (result == -1 && errno == EINTR) {
if (!wait_forever) {
remaining_delta = deadline - base::TimeTicks::Now();
}
result = 0;
} else {
break;
}
}
if (result < 0) {
DPLOG(ERROR) << "kevent (wait " << handle << ")";
return false;
} else if (result > 1) {
DLOG(ERROR) << "kevent (wait " << handle << "): unexpected result "
<< result;
return false;
} else if (result == 0) {
// Timed out.
return false;
}
DCHECK_EQ(result, 1);
if (event.filter != EVFILT_PROC ||
(event.fflags & NOTE_EXIT) == 0 ||
event.ident != static_cast<uintptr_t>(handle)) {
DLOG(ERROR) << "kevent (wait " << handle
<< "): unexpected event: filter=" << event.filter
<< ", fflags=" << event.fflags
<< ", ident=" << event.ident;
return false;
}
return true;
}
#endif // OS_MACOSX
bool WaitForSingleProcess(ProcessHandle handle, base::TimeDelta wait) {
ProcessHandle parent_pid = GetParentProcessId(handle);
ProcessHandle our_pid = Process::Current().handle();
if (parent_pid != our_pid) {
#if defined(OS_MACOSX)
// On Mac we can wait on non child processes.
return WaitForSingleNonChildProcess(handle, wait);
#else
// Currently on Linux we can't handle non child processes.
NOTIMPLEMENTED();
#endif // OS_MACOSX
}
bool waitpid_success;
int status = -1;
if (wait.InMilliseconds() == base::kNoTimeout) {
waitpid_success = (HANDLE_EINTR(waitpid(handle, &status, 0)) != -1);
} else {
status = WaitpidWithTimeout(
handle, wait.InMilliseconds(), &waitpid_success);
}
if (status != -1) {
DCHECK(waitpid_success);
return WIFEXITED(status);
} else {
return false;
}
}
// Return value used by GetAppOutputInternal to encapsulate the various exit
// scenarios from the function.
enum GetAppOutputInternalResult {
EXECUTE_FAILURE,
EXECUTE_SUCCESS,
GOT_MAX_OUTPUT,
};
// Executes the application specified by |argv| and wait for it to exit. Stores
// the output (stdout) in |output|. If |do_search_path| is set, it searches the
// path for the application; in that case, |envp| must be null, and it will use
// the current environment. If |do_search_path| is false, |argv[0]| should fully
// specify the path of the application, and |envp| will be used as the
// environment. Redirects stderr to /dev/null.
// If we successfully start the application and get all requested output, we
// return GOT_MAX_OUTPUT, or if there is a problem starting or exiting
// the application we return RUN_FAILURE. Otherwise we return EXECUTE_SUCCESS.
// The GOT_MAX_OUTPUT return value exists so a caller that asks for limited
// output can treat this as a success, despite having an exit code of SIG_PIPE
// due to us closing the output pipe.
// In the case of EXECUTE_SUCCESS, the application exit code will be returned
// in |*exit_code|, which should be checked to determine if the application
// ran successfully.
static GetAppOutputInternalResult GetAppOutputInternal(
const std::vector<std::string>& argv,
char* const envp[],
std::string* output,
size_t max_output,
bool do_search_path,
int* exit_code) {
// Doing a blocking wait for another command to finish counts as IO.
base::ThreadRestrictions::AssertIOAllowed();
// exit_code must be supplied so calling function can determine success.
DCHECK(exit_code);
*exit_code = EXIT_FAILURE;
int pipe_fd[2];
pid_t pid;
InjectiveMultimap fd_shuffle1, fd_shuffle2;
scoped_ptr<char*[]> argv_cstr(new char*[argv.size() + 1]);
fd_shuffle1.reserve(3);
fd_shuffle2.reserve(3);
// Either |do_search_path| should be false or |envp| should be null, but not
// both.
DCHECK(!do_search_path ^ !envp);
if (pipe(pipe_fd) < 0)
return EXECUTE_FAILURE;
switch (pid = fork()) {
case -1: // error
close(pipe_fd[0]);
close(pipe_fd[1]);
return EXECUTE_FAILURE;
case 0: // child
{
#if defined(OS_MACOSX)
RestoreDefaultExceptionHandler();
#endif
// DANGER: no calls to malloc are allowed from now on:
// http://crbug.com/36678
// Obscure fork() rule: in the child, if you don't end up doing exec*(),
// you call _exit() instead of exit(). This is because _exit() does not
// call any previously-registered (in the parent) exit handlers, which
// might do things like block waiting for threads that don't even exist
// in the child.
int dev_null = open("/dev/null", O_WRONLY);
if (dev_null < 0)
_exit(127);
// Stop type-profiler.
// The profiler should be stopped between fork and exec since it inserts
// locks at new/delete expressions. See http://crbug.com/36678.
base::type_profiler::Controller::Stop();
fd_shuffle1.push_back(InjectionArc(pipe_fd[1], STDOUT_FILENO, true));
fd_shuffle1.push_back(InjectionArc(dev_null, STDERR_FILENO, true));
fd_shuffle1.push_back(InjectionArc(dev_null, STDIN_FILENO, true));
// Adding another element here? Remeber to increase the argument to
// reserve(), above.
std::copy(fd_shuffle1.begin(), fd_shuffle1.end(),
std::back_inserter(fd_shuffle2));
if (!ShuffleFileDescriptors(&fd_shuffle1))
_exit(127);
CloseSuperfluousFds(fd_shuffle2);
for (size_t i = 0; i < argv.size(); i++)
argv_cstr[i] = const_cast<char*>(argv[i].c_str());
argv_cstr[argv.size()] = NULL;
if (do_search_path)
execvp(argv_cstr[0], argv_cstr.get());
else
execve(argv_cstr[0], argv_cstr.get(), envp);
_exit(127);
}
default: // parent
{
// Close our writing end of pipe now. Otherwise later read would not
// be able to detect end of child's output (in theory we could still
// write to the pipe).
close(pipe_fd[1]);
output->clear();
char buffer[256];
size_t output_buf_left = max_output;
ssize_t bytes_read = 1; // A lie to properly handle |max_output == 0|
// case in the logic below.
while (output_buf_left > 0) {
bytes_read = HANDLE_EINTR(read(pipe_fd[0], buffer,
std::min(output_buf_left, sizeof(buffer))));
if (bytes_read <= 0)
break;
output->append(buffer, bytes_read);
output_buf_left -= static_cast<size_t>(bytes_read);
}
close(pipe_fd[0]);
// Always wait for exit code (even if we know we'll declare
// GOT_MAX_OUTPUT).
bool success = WaitForExitCode(pid, exit_code);
// If we stopped because we read as much as we wanted, we return
// GOT_MAX_OUTPUT (because the child may exit due to |SIGPIPE|).
if (!output_buf_left && bytes_read > 0)
return GOT_MAX_OUTPUT;
else if (success)
return EXECUTE_SUCCESS;
return EXECUTE_FAILURE;
}
}
}
bool GetAppOutput(const CommandLine& cl, std::string* output) {
return GetAppOutput(cl.argv(), output);
}
bool GetAppOutput(const std::vector<std::string>& argv, std::string* output) {
// Run |execve()| with the current environment and store "unlimited" data.
int exit_code;
GetAppOutputInternalResult result = GetAppOutputInternal(
argv, NULL, output, std::numeric_limits<std::size_t>::max(), true,
&exit_code);
return result == EXECUTE_SUCCESS && exit_code == EXIT_SUCCESS;
}
// TODO(viettrungluu): Conceivably, we should have a timeout as well, so we
// don't hang if what we're calling hangs.
bool GetAppOutputRestricted(const CommandLine& cl,
std::string* output, size_t max_output) {
// Run |execve()| with the empty environment.
char* const empty_environ = NULL;
int exit_code;
GetAppOutputInternalResult result = GetAppOutputInternal(
cl.argv(), &empty_environ, output, max_output, false, &exit_code);
return result == GOT_MAX_OUTPUT || (result == EXECUTE_SUCCESS &&
exit_code == EXIT_SUCCESS);
}
bool GetAppOutputWithExitCode(const CommandLine& cl,
std::string* output,
int* exit_code) {
// Run |execve()| with the current environment and store "unlimited" data.
GetAppOutputInternalResult result = GetAppOutputInternal(
cl.argv(), NULL, output, std::numeric_limits<std::size_t>::max(), true,
exit_code);
return result == EXECUTE_SUCCESS;
}
bool WaitForProcessesToExit(const FilePath::StringType& executable_name,
base::TimeDelta wait,
const ProcessFilter* filter) {
bool result = false;
// TODO(port): This is inefficient, but works if there are multiple procs.
// TODO(port): use waitpid to avoid leaving zombies around
base::TimeTicks end_time = base::TimeTicks::Now() + wait;
do {
NamedProcessIterator iter(executable_name, filter);
if (!iter.NextProcessEntry()) {
result = true;
break;
}
base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(100));
} while ((end_time - base::TimeTicks::Now()) > base::TimeDelta());
return result;
}
bool CleanupProcesses(const FilePath::StringType& executable_name,
base::TimeDelta wait,
int exit_code,
const ProcessFilter* filter) {
bool exited_cleanly = WaitForProcessesToExit(executable_name, wait, filter);
if (!exited_cleanly)
KillProcesses(executable_name, exit_code, filter);
return exited_cleanly;
}
#if !defined(OS_MACOSX)
namespace {
// Return true if the given child is dead. This will also reap the process.
// Doesn't block.
static bool IsChildDead(pid_t child) {
const pid_t result = HANDLE_EINTR(waitpid(child, NULL, WNOHANG));
if (result == -1) {
DPLOG(ERROR) << "waitpid(" << child << ")";
NOTREACHED();
} else if (result > 0) {
// The child has died.
return true;
}
return false;
}
// A thread class which waits for the given child to exit and reaps it.
// If the child doesn't exit within a couple of seconds, kill it.
class BackgroundReaper : public PlatformThread::Delegate {
public:
BackgroundReaper(pid_t child, unsigned timeout)
: child_(child),
timeout_(timeout) {
}
// Overridden from PlatformThread::Delegate:
virtual void ThreadMain() OVERRIDE {
WaitForChildToDie();
delete this;
}
void WaitForChildToDie() {
// Wait forever case.
if (timeout_ == 0) {
pid_t r = HANDLE_EINTR(waitpid(child_, NULL, 0));
if (r != child_) {
DPLOG(ERROR) << "While waiting for " << child_
<< " to terminate, we got the following result: " << r;
}
return;
}
// There's no good way to wait for a specific child to exit in a timed
// fashion. (No kqueue on Linux), so we just loop and sleep.
// Wait for 2 * timeout_ 500 milliseconds intervals.
for (unsigned i = 0; i < 2 * timeout_; ++i) {
PlatformThread::Sleep(TimeDelta::FromMilliseconds(500));
if (IsChildDead(child_))
return;
}
if (kill(child_, SIGKILL) == 0) {
// SIGKILL is uncatchable. Since the signal was delivered, we can
// just wait for the process to die now in a blocking manner.
if (HANDLE_EINTR(waitpid(child_, NULL, 0)) < 0)
DPLOG(WARNING) << "waitpid";
} else {
DLOG(ERROR) << "While waiting for " << child_ << " to terminate we"
<< " failed to deliver a SIGKILL signal (" << errno << ").";
}
}
private:
const pid_t child_;
// Number of seconds to wait, if 0 then wait forever and do not attempt to
// kill |child_|.
const unsigned timeout_;
DISALLOW_COPY_AND_ASSIGN(BackgroundReaper);
};
} // namespace
void EnsureProcessTerminated(ProcessHandle process) {
// If the child is already dead, then there's nothing to do.
if (IsChildDead(process))
return;
const unsigned timeout = 2; // seconds
BackgroundReaper* reaper = new BackgroundReaper(process, timeout);
PlatformThread::CreateNonJoinable(0, reaper);
}
void EnsureProcessGetsReaped(ProcessHandle process) {
// If the child is already dead, then there's nothing to do.
if (IsChildDead(process))
return;
BackgroundReaper* reaper = new BackgroundReaper(process, 0);
PlatformThread::CreateNonJoinable(0, reaper);
}
#endif // !defined(OS_MACOSX)
} // namespace base
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