blob: d1897fa530c4049c8e5f6bedbd406865aeb93d22 [file] [log] [blame]
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "platform/globals.h"
#if defined(HOST_OS_LINUX)
#include "bin/process.h"
#include <errno.h> // NOLINT
#include <fcntl.h> // NOLINT
#include <poll.h> // NOLINT
#include <stdio.h> // NOLINT
#include <stdlib.h> // NOLINT
#include <string.h> // NOLINT
#include <sys/resource.h> // NOLINT
#include <sys/wait.h> // NOLINT
#include <unistd.h> // NOLINT
#include "bin/dartutils.h"
#include "bin/directory.h"
#include "bin/fdutils.h"
#include "bin/file.h"
#include "bin/lockers.h"
#include "bin/reference_counting.h"
#include "bin/thread.h"
#include "platform/syslog.h"
#include "platform/signal_blocker.h"
#include "platform/utils.h"
extern char** environ;
namespace dart {
namespace bin {
int Process::global_exit_code_ = 0;
Mutex* Process::global_exit_code_mutex_ = nullptr;
Process::ExitHook Process::exit_hook_ = NULL;
// ProcessInfo is used to map a process id to the file descriptor for
// the pipe used to communicate the exit code of the process to Dart.
// ProcessInfo objects are kept in the static singly-linked
// ProcessInfoList.
class ProcessInfo {
public:
ProcessInfo(pid_t pid, intptr_t fd) : pid_(pid), fd_(fd) {}
~ProcessInfo() {
int closed = close(fd_);
if (closed != 0) {
FATAL("Failed to close process exit code pipe");
}
}
pid_t pid() { return pid_; }
intptr_t fd() { return fd_; }
ProcessInfo* next() { return next_; }
void set_next(ProcessInfo* info) { next_ = info; }
private:
pid_t pid_;
intptr_t fd_;
ProcessInfo* next_;
DISALLOW_COPY_AND_ASSIGN(ProcessInfo);
};
// Singly-linked list of ProcessInfo objects for all active processes
// started from Dart.
class ProcessInfoList {
public:
static void Init();
static void Cleanup();
static void AddProcess(pid_t pid, intptr_t fd) {
MutexLocker locker(mutex_);
ProcessInfo* info = new ProcessInfo(pid, fd);
info->set_next(active_processes_);
active_processes_ = info;
}
static intptr_t LookupProcessExitFd(pid_t pid) {
MutexLocker locker(mutex_);
ProcessInfo* current = active_processes_;
while (current != NULL) {
if (current->pid() == pid) {
return current->fd();
}
current = current->next();
}
return 0;
}
static void RemoveProcess(pid_t pid) {
MutexLocker locker(mutex_);
ProcessInfo* prev = NULL;
ProcessInfo* current = active_processes_;
while (current != NULL) {
if (current->pid() == pid) {
if (prev == NULL) {
active_processes_ = current->next();
} else {
prev->set_next(current->next());
}
delete current;
return;
}
prev = current;
current = current->next();
}
}
private:
// Linked list of ProcessInfo objects for all active processes
// started from Dart code.
static ProcessInfo* active_processes_;
// Mutex protecting all accesses to the linked list of active
// processes.
static Mutex* mutex_;
DISALLOW_ALLOCATION();
DISALLOW_IMPLICIT_CONSTRUCTORS(ProcessInfoList);
};
ProcessInfo* ProcessInfoList::active_processes_ = NULL;
Mutex* ProcessInfoList::mutex_ = nullptr;
// The exit code handler sets up a separate thread which waits for child
// processes to terminate. That separate thread can then get the exit code from
// processes that have exited and communicate it to Dart through the
// event loop.
class ExitCodeHandler {
public:
static void Init();
static void Cleanup();
// Notify the ExitCodeHandler that another process exists.
static void ProcessStarted() {
// Multiple isolates could be starting processes at the same
// time. Make sure that only one ExitCodeHandler thread exists.
MonitorLocker locker(monitor_);
process_count_++;
monitor_->Notify();
if (running_) {
return;
}
// Start thread that handles process exits when wait returns.
int result =
Thread::Start("dart:io Process.start", ExitCodeHandlerEntry, 0);
if (result != 0) {
FATAL1("Failed to start exit code handler worker thread %d", result);
}
running_ = true;
}
static void TerminateExitCodeThread() {
MonitorLocker locker(monitor_);
if (!running_) {
return;
}
// Set terminate_done_ to false, so we can use it as a guard for our
// monitor.
running_ = false;
// Wake up the [ExitCodeHandler] thread which is blocked on `wait()` (see
// [ExitCodeHandlerEntry]).
if (TEMP_FAILURE_RETRY(fork()) == 0) {
// We avoid running through registered atexit() handlers because that is
// unnecessary work.
_exit(0);
}
monitor_->Notify();
while (!terminate_done_) {
monitor_->Wait(Monitor::kNoTimeout);
}
}
private:
// Entry point for the separate exit code handler thread started by
// the ExitCodeHandler.
static void ExitCodeHandlerEntry(uword param) {
pid_t pid = 0;
int status = 0;
while (true) {
{
MonitorLocker locker(monitor_);
while (running_ && process_count_ == 0) {
monitor_->Wait(Monitor::kNoTimeout);
}
if (!running_) {
terminate_done_ = true;
monitor_->Notify();
return;
}
}
if ((pid = TEMP_FAILURE_RETRY(wait(&status))) > 0) {
int exit_code = 0;
int negative = 0;
if (WIFEXITED(status)) {
exit_code = WEXITSTATUS(status);
}
if (WIFSIGNALED(status)) {
exit_code = WTERMSIG(status);
negative = 1;
}
intptr_t exit_code_fd = ProcessInfoList::LookupProcessExitFd(pid);
if (exit_code_fd != 0) {
int message[2] = {exit_code, negative};
ssize_t result =
FDUtils::WriteToBlocking(exit_code_fd, &message, sizeof(message));
// If the process has been closed, the read end of the exit
// pipe has been closed. It is therefore not a problem that
// write fails with a broken pipe error. Other errors should
// not happen.
if ((result != -1) && (result != sizeof(message))) {
FATAL("Failed to write entire process exit message");
} else if ((result == -1) && (errno != EPIPE)) {
FATAL1("Failed to write exit code: %d", errno);
}
ProcessInfoList::RemoveProcess(pid);
{
MonitorLocker locker(monitor_);
process_count_--;
}
}
} else if (pid < 0) {
FATAL1("Wait for process exit failed: %d", errno);
}
}
}
static bool terminate_done_;
static int process_count_;
static bool running_;
static Monitor* monitor_;
DISALLOW_ALLOCATION();
DISALLOW_IMPLICIT_CONSTRUCTORS(ExitCodeHandler);
};
bool ExitCodeHandler::running_ = false;
int ExitCodeHandler::process_count_ = 0;
bool ExitCodeHandler::terminate_done_ = false;
Monitor* ExitCodeHandler::monitor_ = nullptr;
class ProcessStarter {
public:
ProcessStarter(Namespace* namespc,
const char* path,
char* arguments[],
intptr_t arguments_length,
const char* working_directory,
char* environment[],
intptr_t environment_length,
ProcessStartMode mode,
intptr_t* in,
intptr_t* out,
intptr_t* err,
intptr_t* id,
intptr_t* exit_event,
char** os_error_message)
: namespc_(namespc),
path_(path),
working_directory_(working_directory),
mode_(mode),
in_(in),
out_(out),
err_(err),
id_(id),
exit_event_(exit_event),
os_error_message_(os_error_message) {
read_in_[0] = -1;
read_in_[1] = -1;
read_err_[0] = -1;
read_err_[1] = -1;
write_out_[0] = -1;
write_out_[1] = -1;
exec_control_[0] = -1;
exec_control_[1] = -1;
program_arguments_ = reinterpret_cast<char**>(Dart_ScopeAllocate(
(arguments_length + 2) * sizeof(*program_arguments_)));
program_arguments_[0] = const_cast<char*>(path_);
for (int i = 0; i < arguments_length; i++) {
program_arguments_[i + 1] = arguments[i];
}
program_arguments_[arguments_length + 1] = NULL;
program_environment_ = NULL;
if (environment != NULL) {
program_environment_ = reinterpret_cast<char**>(Dart_ScopeAllocate(
(environment_length + 1) * sizeof(*program_environment_)));
for (int i = 0; i < environment_length; i++) {
program_environment_[i] = environment[i];
}
program_environment_[environment_length] = NULL;
}
}
int Start() {
// Create pipes required.
int err = CreatePipes();
if (err != 0) {
return err;
}
// Fork to create the new process.
pid_t pid = TEMP_FAILURE_RETRY(fork());
if (pid < 0) {
// Failed to fork.
return CleanupAndReturnError();
} else if (pid == 0) {
// This runs in the new process.
NewProcess();
}
// This runs in the original process.
// If the child process is not started in detached mode, be sure to
// listen for exit-codes, now that we have a non detached child process
// and also Register this child process.
if (Process::ModeIsAttached(mode_)) {
ExitCodeHandler::ProcessStarted();
err = RegisterProcess(pid);
if (err != 0) {
return err;
}
}
// Notify child process to start. This is done to delay the call to exec
// until the process is registered above, and we are ready to receive the
// exit code.
char msg = '1';
int bytes_written =
FDUtils::WriteToBlocking(read_in_[1], &msg, sizeof(msg));
if (bytes_written != sizeof(msg)) {
return CleanupAndReturnError();
}
// Read the result of executing the child process.
close(exec_control_[1]);
exec_control_[1] = -1;
if (Process::ModeIsAttached(mode_)) {
err = ReadExecResult();
} else {
err = ReadDetachedExecResult(&pid);
}
close(exec_control_[0]);
exec_control_[0] = -1;
// Return error code if any failures.
if (err != 0) {
if (Process::ModeIsAttached(mode_)) {
// Since exec() failed, we're not interested in the exit code.
// We close the reading side of the exit code pipe here.
// GetProcessExitCodes will get a broken pipe error when it
// tries to write to the writing side of the pipe and it will
// ignore the error.
close(*exit_event_);
*exit_event_ = -1;
}
CloseAllPipes();
return err;
}
if (Process::ModeHasStdio(mode_)) {
// Connect stdio, stdout and stderr.
FDUtils::SetNonBlocking(read_in_[0]);
*in_ = read_in_[0];
close(read_in_[1]);
FDUtils::SetNonBlocking(write_out_[1]);
*out_ = write_out_[1];
close(write_out_[0]);
FDUtils::SetNonBlocking(read_err_[0]);
*err_ = read_err_[0];
close(read_err_[1]);
} else {
// Close all fds.
close(read_in_[0]);
close(read_in_[1]);
ASSERT(write_out_[0] == -1);
ASSERT(write_out_[1] == -1);
ASSERT(read_err_[0] == -1);
ASSERT(read_err_[1] == -1);
}
ASSERT(exec_control_[0] == -1);
ASSERT(exec_control_[1] == -1);
*id_ = pid;
return 0;
}
private:
static constexpr int kErrorBufferSize = 1024;
int CreatePipes() {
int result;
result = TEMP_FAILURE_RETRY(pipe2(exec_control_, O_CLOEXEC));
if (result < 0) {
return CleanupAndReturnError();
}
// For a detached process the pipe to connect stdout is still used for
// signaling when to do the first fork.
result = TEMP_FAILURE_RETRY(pipe2(read_in_, O_CLOEXEC));
if (result < 0) {
return CleanupAndReturnError();
}
// For detached processes the pipe to connect stderr and stdin are not used.
if (Process::ModeHasStdio(mode_)) {
result = TEMP_FAILURE_RETRY(pipe2(read_err_, O_CLOEXEC));
if (result < 0) {
return CleanupAndReturnError();
}
result = TEMP_FAILURE_RETRY(pipe2(write_out_, O_CLOEXEC));
if (result < 0) {
return CleanupAndReturnError();
}
}
return 0;
}
void NewProcess() {
// Wait for parent process before setting up the child process.
char msg;
int bytes_read = FDUtils::ReadFromBlocking(read_in_[0], &msg, sizeof(msg));
if (bytes_read != sizeof(msg)) {
perror("Failed receiving notification message");
exit(1);
}
if (Process::ModeIsAttached(mode_)) {
ExecProcess();
} else {
ExecDetachedProcess();
}
}
// Tries to find path_ relative to the current namespace unless it should be
// searched in the PATH.
// The path that should be passed to exec is returned in realpath.
// Returns true on success, and false if there was an error that should
// be reported to the parent.
bool FindPathInNamespace(char* realpath, intptr_t realpath_size) {
// Perform a PATH search if there's no slash in the path.
if (strchr(path_, '/') == NULL) {
// TODO(zra): If there is a non-default namespace, the entries in PATH
// should be treated as relative to the namespace.
strncpy(realpath, path_, realpath_size);
realpath[realpath_size - 1] = '\0';
return true;
}
NamespaceScope ns(namespc_, path_);
const int fd =
TEMP_FAILURE_RETRY(openat64(ns.fd(), ns.path(), O_RDONLY | O_CLOEXEC));
if (fd == -1) {
return false;
}
char procpath[PATH_MAX];
snprintf(procpath, PATH_MAX, "/proc/self/fd/%d", fd);
const intptr_t length =
TEMP_FAILURE_RETRY(readlink(procpath, realpath, realpath_size));
if (length < 0) {
FDUtils::SaveErrorAndClose(fd);
return false;
}
realpath[length] = '\0';
FDUtils::SaveErrorAndClose(fd);
return true;
}
void ExecProcess() {
if (mode_ == kNormal) {
if (TEMP_FAILURE_RETRY(dup2(write_out_[0], STDIN_FILENO)) == -1) {
ReportChildError();
}
if (TEMP_FAILURE_RETRY(dup2(read_in_[1], STDOUT_FILENO)) == -1) {
ReportChildError();
}
if (TEMP_FAILURE_RETRY(dup2(read_err_[1], STDERR_FILENO)) == -1) {
ReportChildError();
}
} else {
ASSERT(mode_ == kInheritStdio);
}
if (working_directory_ != NULL &&
!Directory::SetCurrent(namespc_, working_directory_)) {
ReportChildError();
}
if (program_environment_ != NULL) {
environ = program_environment_;
}
char realpath[PATH_MAX];
if (!FindPathInNamespace(realpath, PATH_MAX)) {
ReportChildError();
}
// TODO(dart:io) Test for the existence of execveat, and use it instead.
execvp(realpath, const_cast<char* const*>(program_arguments_));
ReportChildError();
}
void ExecDetachedProcess() {
if (mode_ == kDetached) {
ASSERT(write_out_[0] == -1);
ASSERT(write_out_[1] == -1);
ASSERT(read_err_[0] == -1);
ASSERT(read_err_[1] == -1);
// For a detached process the pipe to connect stdout is only used for
// signaling when to do the first fork.
close(read_in_[0]);
read_in_[0] = -1;
close(read_in_[1]);
read_in_[1] = -1;
} else {
// Don't close any fds if keeping stdio open to the detached process.
ASSERT(mode_ == kDetachedWithStdio);
}
// Fork once more to start a new session.
pid_t pid = TEMP_FAILURE_RETRY(fork());
if (pid < 0) {
ReportChildError();
} else if (pid == 0) {
// Start a new session.
if (TEMP_FAILURE_RETRY(setsid()) == -1) {
ReportChildError();
} else {
// Do a final fork to not be the session leader.
pid = TEMP_FAILURE_RETRY(fork());
if (pid < 0) {
ReportChildError();
} else if (pid == 0) {
if (mode_ == kDetached) {
SetupDetached();
} else {
SetupDetachedWithStdio();
}
if ((working_directory_ != NULL) &&
!Directory::SetCurrent(namespc_, working_directory_)) {
ReportChildError();
}
if (program_environment_ != NULL) {
environ = program_environment_;
}
// Report the final PID and do the exec.
ReportPid(getpid()); // getpid cannot fail.
char realpath[PATH_MAX];
if (!FindPathInNamespace(realpath, PATH_MAX)) {
ReportChildError();
}
// TODO(dart:io) Test for the existence of execveat, and use it
// instead.
execvp(realpath, const_cast<char* const*>(program_arguments_));
ReportChildError();
} else {
// Exit the intermediate process.
exit(0);
}
}
} else {
// Exit the intermediate process.
exit(0);
}
}
int RegisterProcess(pid_t pid) {
int result;
int event_fds[2];
result = TEMP_FAILURE_RETRY(pipe2(event_fds, O_CLOEXEC));
if (result < 0) {
return CleanupAndReturnError();
}
ProcessInfoList::AddProcess(pid, event_fds[1]);
*exit_event_ = event_fds[0];
FDUtils::SetNonBlocking(event_fds[0]);
return 0;
}
int ReadExecResult() {
int child_errno;
int bytes_read = -1;
// Read exec result from child. If no data is returned the exec was
// successful and the exec call closed the pipe. Otherwise the errno
// is written to the pipe.
bytes_read = FDUtils::ReadFromBlocking(exec_control_[0], &child_errno,
sizeof(child_errno));
if (bytes_read == sizeof(child_errno)) {
ReadChildError();
return child_errno;
} else if (bytes_read == -1) {
return errno;
}
return 0;
}
int ReadDetachedExecResult(pid_t* pid) {
int child_errno;
int bytes_read = -1;
// Read exec result from child. If only pid data is returned the exec was
// successful and the exec call closed the pipe. Otherwise the errno
// is written to the pipe as well.
int result[2];
bytes_read =
FDUtils::ReadFromBlocking(exec_control_[0], result, sizeof(result));
if (bytes_read == sizeof(int)) {
*pid = result[0];
} else if (bytes_read == 2 * sizeof(int)) {
*pid = result[0];
child_errno = result[1];
ReadChildError();
return child_errno;
} else if (bytes_read == -1) {
return errno;
}
return 0;
}
void SetupDetached() {
ASSERT(mode_ == kDetached);
// Close all open file descriptors except for exec_control_[1].
int max_fds = sysconf(_SC_OPEN_MAX);
if (max_fds == -1) {
max_fds = _POSIX_OPEN_MAX;
}
for (int fd = 0; fd < max_fds; fd++) {
if (fd != exec_control_[1]) {
close(fd);
}
}
// Re-open stdin, stdout and stderr and connect them to /dev/null.
// The loop above should already have closed all of them, so
// creating new file descriptors should start at STDIN_FILENO.
int fd = TEMP_FAILURE_RETRY(open("/dev/null", O_RDWR));
if (fd != STDIN_FILENO) {
ReportChildError();
}
if (TEMP_FAILURE_RETRY(dup2(STDIN_FILENO, STDOUT_FILENO)) !=
STDOUT_FILENO) {
ReportChildError();
}
if (TEMP_FAILURE_RETRY(dup2(STDIN_FILENO, STDERR_FILENO)) !=
STDERR_FILENO) {
ReportChildError();
}
}
void SetupDetachedWithStdio() {
// Close all open file descriptors except for
// exec_control_[1], write_out_[0], read_in_[1] and
// read_err_[1].
int max_fds = sysconf(_SC_OPEN_MAX);
if (max_fds == -1) {
max_fds = _POSIX_OPEN_MAX;
}
for (int fd = 0; fd < max_fds; fd++) {
if ((fd != exec_control_[1]) && (fd != write_out_[0]) &&
(fd != read_in_[1]) && (fd != read_err_[1])) {
close(fd);
}
}
if (TEMP_FAILURE_RETRY(dup2(write_out_[0], STDIN_FILENO)) == -1) {
ReportChildError();
}
close(write_out_[0]);
if (TEMP_FAILURE_RETRY(dup2(read_in_[1], STDOUT_FILENO)) == -1) {
ReportChildError();
}
close(read_in_[1]);
if (TEMP_FAILURE_RETRY(dup2(read_err_[1], STDERR_FILENO)) == -1) {
ReportChildError();
}
close(read_err_[1]);
}
int CleanupAndReturnError() {
int actual_errno = errno;
// If CleanupAndReturnError is called without an actual errno make
// sure to return an error anyway.
if (actual_errno == 0) {
actual_errno = EPERM;
}
SetChildOsErrorMessage();
CloseAllPipes();
return actual_errno;
}
void SetChildOsErrorMessage() {
char* error_message = DartUtils::ScopedCString(kErrorBufferSize);
Utils::StrError(errno, error_message, kErrorBufferSize);
*os_error_message_ = error_message;
}
void ReportChildError() {
// In the case of failure in the child process write the errno and
// the OS error message to the exec control pipe and exit.
int child_errno = errno;
char error_buf[kErrorBufferSize];
char* os_error_message =
Utils::StrError(errno, error_buf, kErrorBufferSize);
int bytes_written = FDUtils::WriteToBlocking(exec_control_[1], &child_errno,
sizeof(child_errno));
if (bytes_written == sizeof(child_errno)) {
FDUtils::WriteToBlocking(exec_control_[1], os_error_message,
strlen(os_error_message) + 1);
}
close(exec_control_[1]);
// We avoid running through registered atexit() handlers because that is
// unnecessary work.
_exit(1);
}
void ReportPid(int pid) {
// In the case of starting a detached process the actual pid of that process
// is communicated using the exec control pipe.
int bytes_written =
FDUtils::WriteToBlocking(exec_control_[1], &pid, sizeof(pid));
ASSERT(bytes_written == sizeof(int));
USE(bytes_written);
}
void ReadChildError() {
char* message = DartUtils::ScopedCString(kErrorBufferSize);
if (message != NULL) {
FDUtils::ReadFromBlocking(exec_control_[0], message, kErrorBufferSize);
message[kErrorBufferSize - 1] = '\0';
*os_error_message_ = message;
} else {
// Could not get error message. It will be NULL.
ASSERT(*os_error_message_ == NULL);
}
}
void ClosePipe(int* fds) {
for (int i = 0; i < 2; i++) {
if (fds[i] != -1) {
close(fds[i]);
fds[i] = -1;
}
}
}
void CloseAllPipes() {
ClosePipe(exec_control_);
ClosePipe(read_in_);
ClosePipe(read_err_);
ClosePipe(write_out_);
}
int read_in_[2]; // Pipe for stdout to child process.
int read_err_[2]; // Pipe for stderr to child process.
int write_out_[2]; // Pipe for stdin to child process.
int exec_control_[2]; // Pipe to get the result from exec.
char** program_arguments_;
char** program_environment_;
Namespace* namespc_;
const char* path_;
const char* working_directory_;
ProcessStartMode mode_;
intptr_t* in_;
intptr_t* out_;
intptr_t* err_;
intptr_t* id_;
intptr_t* exit_event_;
char** os_error_message_;
DISALLOW_ALLOCATION();
DISALLOW_IMPLICIT_CONSTRUCTORS(ProcessStarter);
};
int Process::Start(Namespace* namespc,
const char* path,
char* arguments[],
intptr_t arguments_length,
const char* working_directory,
char* environment[],
intptr_t environment_length,
ProcessStartMode mode,
intptr_t* in,
intptr_t* out,
intptr_t* err,
intptr_t* id,
intptr_t* exit_event,
char** os_error_message) {
ProcessStarter starter(namespc, path, arguments, arguments_length,
working_directory, environment, environment_length,
mode, in, out, err, id, exit_event, os_error_message);
return starter.Start();
}
static bool CloseProcessBuffers(struct pollfd* fds, int alive) {
int e = errno;
for (int i = 0; i < alive; i++) {
close(fds[i].fd);
}
errno = e;
return false;
}
bool Process::Wait(intptr_t pid,
intptr_t in,
intptr_t out,
intptr_t err,
intptr_t exit_event,
ProcessResult* result) {
// Close input to the process right away.
close(in);
// There is no return from this function using Dart_PropagateError
// as memory used by the buffer lists is freed through their
// destructors.
BufferList out_data;
BufferList err_data;
union {
uint8_t bytes[8];
int32_t ints[2];
} exit_code_data;
struct pollfd fds[3];
fds[0].fd = out;
fds[1].fd = err;
fds[2].fd = exit_event;
for (int i = 0; i < 3; i++) {
fds[i].events = POLLIN;
}
int alive = 3;
while (alive > 0) {
// Blocking call waiting for events from the child process.
if (TEMP_FAILURE_RETRY(poll(fds, alive, -1)) <= 0) {
return CloseProcessBuffers(fds, alive);
}
// Process incoming data.
for (int i = 0; i < alive; i++) {
if ((fds[i].revents & (POLLNVAL | POLLERR)) != 0) {
return CloseProcessBuffers(fds, alive);
}
if ((fds[i].revents & POLLIN) != 0) {
intptr_t avail = FDUtils::AvailableBytes(fds[i].fd);
if (fds[i].fd == out) {
if (!out_data.Read(out, avail)) {
return CloseProcessBuffers(fds, alive);
}
} else if (fds[i].fd == err) {
if (!err_data.Read(err, avail)) {
return CloseProcessBuffers(fds, alive);
}
} else if (fds[i].fd == exit_event) {
if (avail == 8) {
intptr_t b =
TEMP_FAILURE_RETRY(read(exit_event, exit_code_data.bytes, 8));
if (b != 8) {
return CloseProcessBuffers(fds, alive);
}
}
} else {
UNREACHABLE();
}
}
if ((fds[i].revents & POLLHUP) != 0) {
// Remove the pollfd from the list of pollfds.
close(fds[i].fd);
alive--;
if (i < alive) {
fds[i] = fds[alive];
}
// Process the same index again.
i--;
continue;
}
}
}
// All handles closed and all data read.
result->set_stdout_data(out_data.GetData());
result->set_stderr_data(err_data.GetData());
DEBUG_ASSERT(out_data.IsEmpty());
DEBUG_ASSERT(err_data.IsEmpty());
// Calculate the exit code.
intptr_t exit_code = exit_code_data.ints[0];
intptr_t negative = exit_code_data.ints[1];
if (negative != 0) {
exit_code = -exit_code;
}
result->set_exit_code(exit_code);
return true;
}
bool Process::Kill(intptr_t id, int signal) {
return (TEMP_FAILURE_RETRY(kill(id, signal)) != -1);
}
void Process::TerminateExitCodeHandler() {
ExitCodeHandler::TerminateExitCodeThread();
}
intptr_t Process::CurrentProcessId() {
return static_cast<intptr_t>(getpid());
}
static void SaveErrorAndClose(FILE* file) {
int actual_errno = errno;
fclose(file);
errno = actual_errno;
}
int64_t Process::CurrentRSS() {
// The second value in /proc/self/statm is the current RSS in pages.
// It is not possible to use getrusage() because the interested fields are not
// implemented by the linux kernel.
FILE* statm = fopen("/proc/self/statm", "r");
if (statm == NULL) {
return -1;
}
int64_t current_rss_pages = 0;
int matches = fscanf(statm, "%*s%" Pd64 "", &current_rss_pages);
if (matches != 1) {
SaveErrorAndClose(statm);
return -1;
}
fclose(statm);
return current_rss_pages * getpagesize();
}
int64_t Process::MaxRSS() {
struct rusage usage;
usage.ru_maxrss = 0;
int r = getrusage(RUSAGE_SELF, &usage);
if (r < 0) {
return -1;
}
return usage.ru_maxrss * KB;
}
static Mutex* signal_mutex = nullptr;
static SignalInfo* signal_handlers = NULL;
static const int kSignalsCount = 7;
static const int kSignals[kSignalsCount] = {
SIGHUP, SIGINT, SIGTERM, SIGUSR1, SIGUSR2, SIGWINCH,
SIGQUIT // Allow VMService to listen on SIGQUIT.
};
SignalInfo::~SignalInfo() {
close(fd_);
}
static void SignalHandler(int signal) {
MutexLocker lock(signal_mutex);
const SignalInfo* handler = signal_handlers;
while (handler != NULL) {
if (handler->signal() == signal) {
int value = 0;
VOID_TEMP_FAILURE_RETRY(write(handler->fd(), &value, 1));
}
handler = handler->next();
}
}
intptr_t Process::SetSignalHandler(intptr_t signal) {
bool found = false;
for (int i = 0; i < kSignalsCount; i++) {
if (kSignals[i] == signal) {
found = true;
break;
}
}
if (!found) {
return -1;
}
int fds[2];
if (NO_RETRY_EXPECTED(pipe2(fds, O_CLOEXEC)) != 0) {
return -1;
}
ThreadSignalBlocker blocker(kSignalsCount, kSignals);
MutexLocker lock(signal_mutex);
SignalInfo* handler = signal_handlers;
bool listen = true;
sa_handler_t oldact_handler = nullptr;
while (handler != NULL) {
if (handler->signal() == signal) {
oldact_handler = handler->oldact();
listen = false;
break;
}
handler = handler->next();
}
if (listen) {
struct sigaction act = {};
act.sa_handler = SignalHandler;
sigemptyset(&act.sa_mask);
for (int i = 0; i < kSignalsCount; i++) {
sigaddset(&act.sa_mask, kSignals[i]);
}
struct sigaction oldact = {};
int status = NO_RETRY_EXPECTED(sigaction(signal, &act, &oldact));
if (status < 0) {
int err = errno;
close(fds[0]);
close(fds[1]);
errno = err;
return -1;
}
oldact_handler = oldact.sa_handler;
}
signal_handlers =
new SignalInfo(fds[1], signal, oldact_handler, signal_handlers);
return fds[0];
}
void Process::ClearSignalHandler(intptr_t signal, Dart_Port port) {
ThreadSignalBlocker blocker(kSignalsCount, kSignals);
MutexLocker lock(signal_mutex);
SignalInfo* handler = signal_handlers;
sa_handler_t oldact_handler = SIG_DFL;
bool any_removed = false;
bool any_remaining = false;
while (handler != NULL) {
bool remove = false;
if (handler->signal() == signal) {
if ((port == ILLEGAL_PORT) || (handler->port() == port)) {
if (signal_handlers == handler) {
signal_handlers = handler->next();
}
handler->Unlink();
remove = true;
oldact_handler = handler->oldact();
any_removed = true;
} else {
any_remaining = true;
}
}
SignalInfo* next = handler->next();
if (remove) {
delete handler;
}
handler = next;
}
if (any_removed && !any_remaining) {
struct sigaction act = {};
act.sa_handler = oldact_handler;
VOID_NO_RETRY_EXPECTED(sigaction(signal, &act, NULL));
}
}
void Process::ClearSignalHandlerByFd(intptr_t fd, Dart_Port port) {
ThreadSignalBlocker blocker(kSignalsCount, kSignals);
MutexLocker lock(signal_mutex);
SignalInfo* handler = signal_handlers;
sa_handler_t oldact_handler = SIG_DFL;
bool any_remaining = false;
intptr_t signal = -1;
while (handler != NULL) {
bool remove = false;
if (handler->fd() == fd) {
if ((port == ILLEGAL_PORT) || (handler->port() == port)) {
if (signal_handlers == handler) {
signal_handlers = handler->next();
}
handler->Unlink();
remove = true;
signal = handler->signal();
} else {
any_remaining = true;
}
}
SignalInfo* next = handler->next();
if (remove) {
delete handler;
}
handler = next;
}
if ((signal != -1) && !any_remaining) {
struct sigaction act = {};
act.sa_handler = oldact_handler;
VOID_NO_RETRY_EXPECTED(sigaction(signal, &act, NULL));
}
}
void ProcessInfoList::Init() {
ASSERT(ProcessInfoList::mutex_ == nullptr);
ProcessInfoList::mutex_ = new Mutex();
}
void ProcessInfoList::Cleanup() {
ASSERT(ProcessInfoList::mutex_ != nullptr);
delete ProcessInfoList::mutex_;
ProcessInfoList::mutex_ = nullptr;
}
void ExitCodeHandler::Init() {
ASSERT(ExitCodeHandler::monitor_ == nullptr);
ExitCodeHandler::monitor_ = new Monitor();
}
void ExitCodeHandler::Cleanup() {
ASSERT(ExitCodeHandler::monitor_ != nullptr);
delete ExitCodeHandler::monitor_;
ExitCodeHandler::monitor_ = nullptr;
}
void Process::Init() {
ExitCodeHandler::Init();
ProcessInfoList::Init();
ASSERT(signal_mutex == nullptr);
signal_mutex = new Mutex();
ASSERT(Process::global_exit_code_mutex_ == nullptr);
Process::global_exit_code_mutex_ = new Mutex();
}
void Process::Cleanup() {
ClearAllSignalHandlers();
ASSERT(signal_mutex != nullptr);
delete signal_mutex;
signal_mutex = nullptr;
ASSERT(Process::global_exit_code_mutex_ != nullptr);
delete Process::global_exit_code_mutex_;
Process::global_exit_code_mutex_ = nullptr;
ProcessInfoList::Cleanup();
ExitCodeHandler::Cleanup();
}
} // namespace bin
} // namespace dart
#endif // defined(HOST_OS_LINUX)