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qtbase/src/corelib/io/qprocess_unix.cpp
Marc Mutz 80b6bcc385 Short live Q_CONSTINIT! 
It expands to the first available of

- constinit (C++20)
- [[clang::require_constant_initialization]] (Clang)
- __constinit (GCC >= 10)

Use it around the code (on and near static QBasicAtomic; this patch
makes no attempt to find all statics in qtbase).

[ChangeLog][QtCore][QtGlobal] Added macro Q_CONSTINIT.

Fixes: QTBUG-100484
Change-Id: I11e0363a7acb3464476859d12ec7f94319d82be7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
2022-03-26 17:15:02 +01:00

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/****************************************************************************
**
** Copyright (C) 2020 The Qt Company Ltd.
** Copyright (C) 2022 Intel Corporation.
** Copyright (C) 2021 Alex Trotsenko.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
//#define QPROCESS_DEBUG
#include "qdebug.h"
#include <private/qdebug_p.h>
#include "qplatformdefs.h"
#include "qprocess.h"
#include "qprocess_p.h"
#include "qstandardpaths.h"
#include "private/qcore_unix_p.h"
#include "private/qlocking_p.h"
#ifdef Q_OS_MAC
#include <private/qcore_mac_p.h>
#endif
#include <private/qcoreapplication_p.h>
#include <private/qthread_p.h>
#include <qfile.h>
#include <qfileinfo.h>
#include <qdir.h>
#include <qlist.h>
#include <qmutex.h>
#include <qsocketnotifier.h>
#include <qthread.h>
#ifdef Q_OS_QNX
# include <sys/neutrino.h>
#endif
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#if QT_CONFIG(process)
#include <forkfd.h>
#endif
QT_BEGIN_NAMESPACE
using namespace Qt::StringLiterals;
#if !defined(Q_OS_DARWIN)
QT_BEGIN_INCLUDE_NAMESPACE
extern char **environ;
QT_END_INCLUDE_NAMESPACE
QProcessEnvironment QProcessEnvironment::systemEnvironment()
{
QProcessEnvironment env;
const char *entry;
for (int count = 0; (entry = environ[count]); ++count) {
const char *equal = strchr(entry, '=');
if (!equal)
continue;
QByteArray name(entry, equal - entry);
QByteArray value(equal + 1);
env.d->vars.insert(QProcessEnvironmentPrivate::Key(name),
QProcessEnvironmentPrivate::Value(value));
}
return env;
}
#endif // !defined(Q_OS_DARWIN)
#if QT_CONFIG(process)
namespace {
struct AutoPipe
{
int pipe[2] = { -1, -1 };
AutoPipe(int flags = 0)
{
qt_safe_pipe(pipe, flags);
}
~AutoPipe()
{
for (int fd : pipe) {
if (fd >= 0)
qt_safe_close(fd);
}
}
explicit operator bool() const { return pipe[0] >= 0; }
int &operator[](int idx) { return pipe[idx]; }
int operator[](int idx) const { return pipe[idx]; }
};
struct ChildError
{
qint64 code;
char function[8];
};
// Used for argv and envp arguments to execve()
struct CharPointerList
{
std::unique_ptr<char *[]> pointers;
CharPointerList(const QString &argv0, const QStringList &args);
explicit CharPointerList(const QProcessEnvironmentPrivate *env);
private:
QByteArray data;
void updatePointers(qsizetype count);
};
struct QProcessPoller
{
QProcessPoller(const QProcessPrivate &proc);
int poll(const QDeadlineTimer &deadline);
pollfd &stdinPipe() { return pfds[0]; }
pollfd &stdoutPipe() { return pfds[1]; }
pollfd &stderrPipe() { return pfds[2]; }
pollfd &forkfd() { return pfds[3]; }
enum { n_pfds = 4 };
pollfd pfds[n_pfds];
};
QProcessPoller::QProcessPoller(const QProcessPrivate &proc)
{
for (int i = 0; i < n_pfds; i++)
pfds[i] = qt_make_pollfd(-1, POLLIN);
stdoutPipe().fd = proc.stdoutChannel.pipe[0];
stderrPipe().fd = proc.stderrChannel.pipe[0];
if (!proc.writeBuffer.isEmpty()) {
stdinPipe().fd = proc.stdinChannel.pipe[1];
stdinPipe().events = POLLOUT;
}
forkfd().fd = proc.forkfd;
}
int QProcessPoller::poll(const QDeadlineTimer &deadline)
{
return qt_poll_msecs(pfds, n_pfds, deadline.remainingTime());
}
CharPointerList::CharPointerList(const QString &program, const QStringList &args)
{
qsizetype count = 1 + args.size();
pointers.reset(new char *[count + 1]);
pointers[count] = nullptr;
// we abuse the pointer array to store offsets first (QByteArray will
// reallocate, after all)
pointers[0] = reinterpret_cast<char *>(0);
data = QFile::encodeName(program);
data += '\0';
const auto end = args.end();
auto it = args.begin();
for (qsizetype i = 1; it != end; ++it, ++i) {
pointers[i] = reinterpret_cast<char *>(data.size());
data += QFile::encodeName(*it);
data += '\0';
}
updatePointers(count);
}
CharPointerList::CharPointerList(const QProcessEnvironmentPrivate *environment)
{
if (!environment)
return;
const QProcessEnvironmentPrivate::Map &env = environment->vars;
qsizetype count = env.size();
pointers.reset(new char *[count + 1]);
pointers[count] = nullptr;
const auto end = env.end();
auto it = env.begin();
for (qsizetype i = 0; it != end; ++it, ++i) {
// we abuse the pointer array to store offsets first (QByteArray will
// reallocate, after all)
pointers[i] = reinterpret_cast<char *>(data.size());
data += it.key();
data += '=';
data += it->bytes();
data += '\0';
}
updatePointers(count);
}
void CharPointerList::updatePointers(qsizetype count)
{
char *const base = const_cast<char *>(data.constBegin());
for (qsizetype i = 0; i < count; ++i)
pointers[i] = base + qptrdiff(pointers[i]);
}
} // anonymous namespace
static bool qt_pollfd_check(const pollfd &pfd, short revents)
{
return pfd.fd >= 0 && (pfd.revents & (revents | POLLHUP | POLLERR | POLLNVAL)) != 0;
}
static int qt_create_pipe(int *pipe)
{
if (pipe[0] != -1)
qt_safe_close(pipe[0]);
if (pipe[1] != -1)
qt_safe_close(pipe[1]);
int pipe_ret = qt_safe_pipe(pipe);
if (pipe_ret != 0) {
qErrnoWarning("QProcessPrivate::createPipe: Cannot create pipe %p", pipe);
}
return pipe_ret;
}
void QProcessPrivate::destroyPipe(int *pipe)
{
if (pipe[1] != -1) {
qt_safe_close(pipe[1]);
pipe[1] = -1;
}
if (pipe[0] != -1) {
qt_safe_close(pipe[0]);
pipe[0] = -1;
}
}
void QProcessPrivate::closeChannel(Channel *channel)
{
delete channel->notifier;
channel->notifier = nullptr;
destroyPipe(channel->pipe);
}
void QProcessPrivate::cleanup()
{
q_func()->setProcessState(QProcess::NotRunning);
closeChannels();
delete stateNotifier;
stateNotifier = nullptr;
destroyPipe(childStartedPipe);
pid = 0;
if (forkfd != -1) {
qt_safe_close(forkfd);
forkfd = -1;
}
}
/*
Create the pipes to a QProcessPrivate::Channel.
*/
bool QProcessPrivate::openChannel(Channel &channel)
{
Q_Q(QProcess);
if (channel.type == Channel::Normal) {
// we're piping this channel to our own process
if (qt_create_pipe(channel.pipe) != 0)
return false;
// create the socket notifiers
if (threadData.loadRelaxed()->hasEventDispatcher()) {
if (&channel == &stdinChannel) {
channel.notifier = new QSocketNotifier(QSocketNotifier::Write, q);
channel.notifier->setSocket(channel.pipe[1]);
QObject::connect(channel.notifier, SIGNAL(activated(QSocketDescriptor)),
q, SLOT(_q_canWrite()));
} else {
channel.notifier = new QSocketNotifier(QSocketNotifier::Read, q);
channel.notifier->setSocket(channel.pipe[0]);
const char *receiver;
if (&channel == &stdoutChannel)
receiver = SLOT(_q_canReadStandardOutput());
else
receiver = SLOT(_q_canReadStandardError());
QObject::connect(channel.notifier, SIGNAL(activated(QSocketDescriptor)),
q, receiver);
}
}
return true;
} else if (channel.type == Channel::Redirect) {
// we're redirecting the channel to/from a file
QByteArray fname = QFile::encodeName(channel.file);
if (&channel == &stdinChannel) {
// try to open in read-only mode
channel.pipe[1] = -1;
if ( (channel.pipe[0] = qt_safe_open(fname, O_RDONLY)) != -1)
return true; // success
setErrorAndEmit(QProcess::FailedToStart,
QProcess::tr("Could not open input redirection for reading"));
} else {
int mode = O_WRONLY | O_CREAT;
if (channel.append)
mode |= O_APPEND;
else
mode |= O_TRUNC;
channel.pipe[0] = -1;
if ( (channel.pipe[1] = qt_safe_open(fname, mode, 0666)) != -1)
return true; // success
setErrorAndEmit(QProcess::FailedToStart,
QProcess::tr("Could not open input redirection for reading"));
}
cleanup();
return false;
} else {
Q_ASSERT_X(channel.process, "QProcess::start", "Internal error");
Channel *source;
Channel *sink;
if (channel.type == Channel::PipeSource) {
// we are the source
source = &channel;
sink = &channel.process->stdinChannel;
Q_ASSERT(source == &stdoutChannel);
Q_ASSERT(sink->process == this && sink->type == Channel::PipeSink);
} else {
// we are the sink;
source = &channel.process->stdoutChannel;
sink = &channel;
Q_ASSERT(sink == &stdinChannel);
Q_ASSERT(source->process == this && source->type == Channel::PipeSource);
}
if (source->pipe[1] != INVALID_Q_PIPE || sink->pipe[0] != INVALID_Q_PIPE) {
// already created, do nothing
return true;
} else {
Q_ASSERT(source->pipe[0] == INVALID_Q_PIPE && source->pipe[1] == INVALID_Q_PIPE);
Q_ASSERT(sink->pipe[0] == INVALID_Q_PIPE && sink->pipe[1] == INVALID_Q_PIPE);
Q_PIPE pipe[2] = { -1, -1 };
if (qt_create_pipe(pipe) != 0)
return false;
sink->pipe[0] = pipe[0];
source->pipe[1] = pipe[1];
return true;
}
}
}
void QProcessPrivate::commitChannels()
{
// copy the stdin socket if asked to (without closing on exec)
if (stdinChannel.pipe[0] != INVALID_Q_PIPE)
qt_safe_dup2(stdinChannel.pipe[0], STDIN_FILENO, 0);
// copy the stdout and stderr if asked to
if (stdoutChannel.pipe[1] != INVALID_Q_PIPE)
qt_safe_dup2(stdoutChannel.pipe[1], STDOUT_FILENO, 0);
if (stderrChannel.pipe[1] != INVALID_Q_PIPE) {
qt_safe_dup2(stderrChannel.pipe[1], STDERR_FILENO, 0);
} else {
// merge stdout and stderr if asked to
if (processChannelMode == QProcess::MergedChannels)
qt_safe_dup2(STDOUT_FILENO, STDERR_FILENO, 0);
}
}
static QString resolveExecutable(const QString &program)
{
#ifdef Q_OS_DARWIN
// allow invoking of .app bundles on the Mac.
QFileInfo fileInfo(program);
if (program.endsWith(".app"_L1) && fileInfo.isDir()) {
QCFType<CFURLRef> url = CFURLCreateWithFileSystemPath(0,
QCFString(fileInfo.absoluteFilePath()),
kCFURLPOSIXPathStyle, true);
{
// CFBundle is not reentrant, since CFBundleCreate might return a reference
// to a cached bundle object. Protect the bundle calls with a mutex lock.
Q_CONSTINIT static QBasicMutex cfbundleMutex;
const auto locker = qt_scoped_lock(cfbundleMutex);
QCFType<CFBundleRef> bundle = CFBundleCreate(0, url);
// 'executableURL' can be either relative or absolute ...
QCFType<CFURLRef> executableURL = CFBundleCopyExecutableURL(bundle);
// not to depend on caching - make sure it's always absolute.
url = CFURLCopyAbsoluteURL(executableURL);
}
if (url) {
const QCFString str = CFURLCopyFileSystemPath(url, kCFURLPOSIXPathStyle);
return QString::fromCFString(str);
}
}
#endif
if (!program.contains(u'/')) {
// findExecutable() returns its argument if it's an absolute path,
// otherwise it searches $PATH; returns empty if not found (we handle
// that case much later)
return QStandardPaths::findExecutable(program);
}
return program;
}
void QProcessPrivate::startProcess()
{
Q_Q(QProcess);
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::startProcess()");
#endif
// Initialize pipes
if (!openChannels() || qt_create_pipe(childStartedPipe) != 0) {
setErrorAndEmit(QProcess::FailedToStart, qt_error_string(errno));
cleanup();
return;
}
if (threadData.loadRelaxed()->hasEventDispatcher()) {
// Set up to notify about startup completion (and premature death).
// Once the process has started successfully, we reconfigure the
// notifier to watch the fork_fd for expected death.
stateNotifier = new QSocketNotifier(childStartedPipe[0],
QSocketNotifier::Read, q);
QObject::connect(stateNotifier, SIGNAL(activated(QSocketDescriptor)),
q, SLOT(_q_startupNotification()));
}
// Start the process (platform dependent)
q->setProcessState(QProcess::Starting);
// Prepare the arguments and the environment
const CharPointerList argv(resolveExecutable(program), arguments);
const CharPointerList envp(environment.d.constData());
// Encode the working directory if it's non-empty, otherwise just pass 0.
const char *workingDirPtr = nullptr;
QByteArray encodedWorkingDirectory;
if (!workingDirectory.isEmpty()) {
encodedWorkingDirectory = QFile::encodeName(workingDirectory);
workingDirPtr = encodedWorkingDirectory.constData();
}
int ffdflags = FFD_CLOEXEC;
// QTBUG-86285
#if !QT_CONFIG(forkfd_pidfd)
ffdflags |= FFD_USE_FORK;
#endif
pid_t childPid;
forkfd = ::forkfd(ffdflags , &childPid);
int lastForkErrno = errno;
if (forkfd == -1) {
// Cleanup, report error and return
#if defined (QPROCESS_DEBUG)
qDebug("fork failed: %ls", qUtf16Printable(qt_error_string(lastForkErrno)));
#endif
q->setProcessState(QProcess::NotRunning);
setErrorAndEmit(QProcess::FailedToStart,
QProcess::tr("Resource error (fork failure): %1").arg(qt_error_string(lastForkErrno)));
cleanup();
return;
}
// Start the child.
if (forkfd == FFD_CHILD_PROCESS) {
execChild(workingDirPtr, argv.pointers.get(), envp.pointers.get());
::_exit(-1);
}
pid = qint64(childPid);
Q_ASSERT(pid > 0);
// parent
// close the ends we don't use and make all pipes non-blocking
qt_safe_close(childStartedPipe[1]);
childStartedPipe[1] = -1;
if (stdinChannel.pipe[0] != -1) {
qt_safe_close(stdinChannel.pipe[0]);
stdinChannel.pipe[0] = -1;
}
if (stdinChannel.pipe[1] != -1)
::fcntl(stdinChannel.pipe[1], F_SETFL, ::fcntl(stdinChannel.pipe[1], F_GETFL) | O_NONBLOCK);
if (stdoutChannel.pipe[1] != -1) {
qt_safe_close(stdoutChannel.pipe[1]);
stdoutChannel.pipe[1] = -1;
}
if (stdoutChannel.pipe[0] != -1)
::fcntl(stdoutChannel.pipe[0], F_SETFL, ::fcntl(stdoutChannel.pipe[0], F_GETFL) | O_NONBLOCK);
if (stderrChannel.pipe[1] != -1) {
qt_safe_close(stderrChannel.pipe[1]);
stderrChannel.pipe[1] = -1;
}
if (stderrChannel.pipe[0] != -1)
::fcntl(stderrChannel.pipe[0], F_SETFL, ::fcntl(stderrChannel.pipe[0], F_GETFL) | O_NONBLOCK);
}
void QProcessPrivate::execChild(const char *workingDir, char **argv, char **envp)
{
::signal(SIGPIPE, SIG_DFL); // reset the signal that we ignored
ChildError error = { 0, {} }; // force zeroing of function[8]
// Render channels configuration.
commitChannels();
// make sure this fd is closed if execv() succeeds
qt_safe_close(childStartedPipe[0]);
// enter the working directory
if (workingDir && QT_CHDIR(workingDir) == -1) {
// failed, stop the process
strcpy(error.function, "chdir");
goto report_errno;
}
if (childProcessModifier)
childProcessModifier();
// execute the process
if (!envp) {
qt_safe_execv(argv[0], argv);
strcpy(error.function, "execvp");
} else {
#if defined (QPROCESS_DEBUG)
fprintf(stderr, "QProcessPrivate::execChild() starting %s\n", argv[0]);
#endif
qt_safe_execve(argv[0], argv, envp);
strcpy(error.function, "execve");
}
// notify failure
// don't use strerror or any other routines that may allocate memory, since
// some buggy libc versions can deadlock on locked mutexes.
report_errno:
error.code = errno;
qt_safe_write(childStartedPipe[1], &error, sizeof(error));
childStartedPipe[1] = -1;
}
bool QProcessPrivate::processStarted(QString *errorMessage)
{
Q_Q(QProcess);
ChildError buf;
int ret = qt_safe_read(childStartedPipe[0], &buf, sizeof(buf));
if (stateNotifier) {
stateNotifier->setEnabled(false);
stateNotifier->disconnect(q);
}
qt_safe_close(childStartedPipe[0]);
childStartedPipe[0] = -1;
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::processStarted() == %s", ret <= 0 ? "true" : "false");
#endif
if (ret <= 0) { // process successfully started
if (stateNotifier) {
QObject::connect(stateNotifier, SIGNAL(activated(QSocketDescriptor)),
q, SLOT(_q_processDied()));
stateNotifier->setSocket(forkfd);
stateNotifier->setEnabled(true);
}
if (stdoutChannel.notifier)
stdoutChannel.notifier->setEnabled(true);
if (stderrChannel.notifier)
stderrChannel.notifier->setEnabled(true);
return true;
}
// did we read an error message?
if (errorMessage)
*errorMessage = QLatin1StringView(buf.function) + ": "_L1 + qt_error_string(buf.code);
return false;
}
qint64 QProcessPrivate::bytesAvailableInChannel(const Channel *channel) const
{
Q_ASSERT(channel->pipe[0] != INVALID_Q_PIPE);
int nbytes = 0;
qint64 available = 0;
if (::ioctl(channel->pipe[0], FIONREAD, (char *) &nbytes) >= 0)
available = (qint64) nbytes;
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::bytesAvailableInChannel(%d) == %lld", int(channel - &stdinChannel), available);
#endif
return available;
}
qint64 QProcessPrivate::readFromChannel(const Channel *channel, char *data, qint64 maxlen)
{
Q_ASSERT(channel->pipe[0] != INVALID_Q_PIPE);
qint64 bytesRead = qt_safe_read(channel->pipe[0], data, maxlen);
#if defined QPROCESS_DEBUG
int save_errno = errno;
qDebug("QProcessPrivate::readFromChannel(%d, %p \"%s\", %lld) == %lld",
int(channel - &stdinChannel),
data, QtDebugUtils::toPrintable(data, bytesRead, 16).constData(), maxlen, bytesRead);
errno = save_errno;
#endif
if (bytesRead == -1 && errno == EWOULDBLOCK)
return -2;
return bytesRead;
}
/*! \reimp
*/
qint64 QProcess::writeData(const char *data, qint64 len)
{
Q_D(QProcess);
if (d->stdinChannel.closed) {
#if defined QPROCESS_DEBUG
qDebug("QProcess::writeData(%p \"%s\", %lld) == 0 (write channel closing)",
data, QtDebugUtils::toPrintable(data, len, 16).constData(), len);
#endif
return 0;
}
d->write(data, len);
if (d->stdinChannel.notifier)
d->stdinChannel.notifier->setEnabled(true);
#if defined QPROCESS_DEBUG
qDebug("QProcess::writeData(%p \"%s\", %lld) == %lld (written to buffer)",
data, QtDebugUtils::toPrintable(data, len, 16).constData(), len, len);
#endif
return len;
}
bool QProcessPrivate::_q_canWrite()
{
if (writeBuffer.isEmpty()) {
if (stdinChannel.notifier)
stdinChannel.notifier->setEnabled(false);
#if defined QPROCESS_DEBUG
qDebug("QProcessPrivate::canWrite(), not writing anything (empty write buffer).");
#endif
return false;
}
const bool writeSucceeded = writeToStdin();
if (writeBuffer.isEmpty() && stdinChannel.closed)
closeWriteChannel();
else if (stdinChannel.notifier)
stdinChannel.notifier->setEnabled(!writeBuffer.isEmpty());
return writeSucceeded;
}
bool QProcessPrivate::writeToStdin()
{
const char *data = writeBuffer.readPointer();
const qint64 bytesToWrite = writeBuffer.nextDataBlockSize();
qint64 written = qt_safe_write_nosignal(stdinChannel.pipe[1], data, bytesToWrite);
#if defined QPROCESS_DEBUG
qDebug("QProcessPrivate::writeToStdin(), write(%p \"%s\", %lld) == %lld", data,
QtDebugUtils::toPrintable(data, bytesToWrite, 16).constData(), bytesToWrite, written);
if (written == -1)
qDebug("QProcessPrivate::writeToStdin(), failed to write (%ls)", qUtf16Printable(qt_error_string(errno)));
#endif
if (written == -1) {
// If the O_NONBLOCK flag is set and If some data can be written without blocking
// the process, write() will transfer what it can and return the number of bytes written.
// Otherwise, it will return -1 and set errno to EAGAIN
if (errno == EAGAIN)
return true;
closeChannel(&stdinChannel);
setErrorAndEmit(QProcess::WriteError);
return false;
}
writeBuffer.free(written);
if (!emittedBytesWritten && written != 0) {
emittedBytesWritten = true;
emit q_func()->bytesWritten(written);
emittedBytesWritten = false;
}
return true;
}
void QProcessPrivate::terminateProcess()
{
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::terminateProcess() pid=%jd", intmax_t(pid));
#endif
if (pid > 0)
::kill(pid_t(pid), SIGTERM);
}
void QProcessPrivate::killProcess()
{
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::killProcess() pid=%jd", intmax_t(pid));
#endif
if (pid > 0)
::kill(pid_t(pid), SIGKILL);
}
bool QProcessPrivate::waitForStarted(const QDeadlineTimer &deadline)
{
const qint64 msecs = deadline.remainingTime();
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::waitForStarted(%lld) waiting for child to start (fd = %d)",
msecs, childStartedPipe[0]);
#endif
pollfd pfd = qt_make_pollfd(childStartedPipe[0], POLLIN);
if (qt_poll_msecs(&pfd, 1, msecs) == 0) {
setError(QProcess::Timedout);
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::waitForStarted(%lld) == false (timed out)", msecs);
#endif
return false;
}
bool startedEmitted = _q_startupNotification();
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::waitForStarted() == %s", startedEmitted ? "true" : "false");
#endif
return startedEmitted;
}
bool QProcessPrivate::waitForReadyRead(const QDeadlineTimer &deadline)
{
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::waitForReadyRead(%lld)", deadline.remainingTime());
#endif
forever {
QProcessPoller poller(*this);
int ret = poller.poll(deadline);
if (ret < 0) {
break;
}
if (ret == 0) {
setError(QProcess::Timedout);
return false;
}
// This calls QProcessPrivate::tryReadFromChannel(), which returns true
// if we emitted readyRead() signal on the current read channel.
bool readyReadEmitted = false;
if (qt_pollfd_check(poller.stdoutPipe(), POLLIN) && _q_canReadStandardOutput())
readyReadEmitted = true;
if (qt_pollfd_check(poller.stderrPipe(), POLLIN) && _q_canReadStandardError())
readyReadEmitted = true;
if (readyReadEmitted)
return true;
if (qt_pollfd_check(poller.stdinPipe(), POLLOUT))
_q_canWrite();
// Signals triggered by I/O may have stopped this process:
if (processState == QProcess::NotRunning)
return false;
// We do this after checking the pipes, so we cannot reach it as long
// as there is any data left to be read from an already dead process.
if (qt_pollfd_check(poller.forkfd(), POLLIN)) {
processFinished();
return false;
}
}
return false;
}
bool QProcessPrivate::waitForBytesWritten(const QDeadlineTimer &deadline)
{
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::waitForBytesWritten(%lld)", deadline.remainingTime());
#endif
while (!writeBuffer.isEmpty()) {
QProcessPoller poller(*this);
int ret = poller.poll(deadline);
if (ret < 0) {
break;
}
if (ret == 0) {
setError(QProcess::Timedout);
return false;
}
if (qt_pollfd_check(poller.stdinPipe(), POLLOUT))
return _q_canWrite();
if (qt_pollfd_check(poller.stdoutPipe(), POLLIN))
_q_canReadStandardOutput();
if (qt_pollfd_check(poller.stderrPipe(), POLLIN))
_q_canReadStandardError();
// Signals triggered by I/O may have stopped this process:
if (processState == QProcess::NotRunning)
return false;
if (qt_pollfd_check(poller.forkfd(), POLLIN)) {
processFinished();
return false;
}
}
return false;
}
bool QProcessPrivate::waitForFinished(const QDeadlineTimer &deadline)
{
#if defined (QPROCESS_DEBUG)
qDebug("QProcessPrivate::waitForFinished(%lld)", deadline.remainingTime());
#endif
forever {
QProcessPoller poller(*this);
int ret = poller.poll(deadline);
if (ret < 0) {
break;
}
if (ret == 0) {
setError(QProcess::Timedout);
return false;
}
if (qt_pollfd_check(poller.stdinPipe(), POLLOUT))
_q_canWrite();
if (qt_pollfd_check(poller.stdoutPipe(), POLLIN))
_q_canReadStandardOutput();
if (qt_pollfd_check(poller.stderrPipe(), POLLIN))
_q_canReadStandardError();
// Signals triggered by I/O may have stopped this process:
if (processState == QProcess::NotRunning)
return true;
if (qt_pollfd_check(poller.forkfd(), POLLIN)) {
processFinished();
return true;
}
}
return false;
}
void QProcessPrivate::waitForDeadChild()
{
Q_ASSERT(forkfd != -1);
// read the process information from our fd
forkfd_info info;
int ret;
EINTR_LOOP(ret, forkfd_wait(forkfd, &info, nullptr));
exitCode = info.status;
crashed = info.code != CLD_EXITED;
delete stateNotifier;
stateNotifier = nullptr;
EINTR_LOOP(ret, forkfd_close(forkfd));
forkfd = -1; // Child is dead, don't try to kill it anymore
#if defined QPROCESS_DEBUG
qDebug() << "QProcessPrivate::waitForDeadChild() dead with exitCode"
<< exitCode << ", crashed?" << crashed;
#endif
}
bool QProcessPrivate::startDetached(qint64 *pid)
{
QByteArray encodedWorkingDirectory = QFile::encodeName(workingDirectory);
#ifdef PIPE_BUF
static_assert(PIPE_BUF >= sizeof(ChildError));
#else
static_assert(_POSIX_PIPE_BUF >= sizeof(ChildError));
#endif
ChildError childStatus = { 0, {} };
AutoPipe startedPipe, pidPipe;
if (!startedPipe || !pidPipe) {
setErrorAndEmit(QProcess::FailedToStart, "pipe: "_L1 + qt_error_string(errno));
return false;
}
if (!openChannelsForDetached()) {
// openChannel sets the error string
closeChannels();
return false;
}
const CharPointerList argv(resolveExecutable(program), arguments);
const CharPointerList envp(environment.d.constData());
pid_t childPid = fork();
if (childPid == 0) {
::signal(SIGPIPE, SIG_DFL); // reset the signal that we ignored
::setsid();
qt_safe_close(startedPipe[0]);
qt_safe_close(pidPipe[0]);
auto reportFailed = [&](const char *function) {
childStatus.code = errno;
strcpy(childStatus.function, function);
qt_safe_write(startedPipe[1], &childStatus, sizeof(childStatus));
::_exit(1);
};
if (!encodedWorkingDirectory.isEmpty()) {
if (QT_CHDIR(encodedWorkingDirectory.constData()) < 0)
reportFailed("chdir: ");
}
pid_t doubleForkPid = fork();
if (doubleForkPid == 0) {
// Render channels configuration.
commitChannels();
if (envp.pointers)
qt_safe_execve(argv.pointers[0], argv.pointers.get(), envp.pointers.get());
else
qt_safe_execv(argv.pointers[0], argv.pointers.get());
reportFailed("execv: ");
} else if (doubleForkPid == -1) {
reportFailed("fork: ");
}
// success
qt_safe_write(pidPipe[1], &doubleForkPid, sizeof(pid_t));
::_exit(1);
}
int savedErrno = errno;
closeChannels();
if (childPid == -1) {
setErrorAndEmit(QProcess::FailedToStart, "fork: "_L1 + qt_error_string(savedErrno));
return false;
}
// close the writing ends of the pipes so we can properly get EOFs
qt_safe_close(pidPipe[1]);
qt_safe_close(startedPipe[1]);
pidPipe[1] = startedPipe[1] = -1;
// This read() will block until we're cleared to proceed. If it returns 0
// (EOF), it means the direct child has exited and the grandchild
// successfully execve()'d the target process. If it returns any positive
// result, it means one of the two children wrote an error result. Negative
// values should not happen.
ssize_t startResult = qt_safe_read(startedPipe[0], &childStatus, sizeof(childStatus));
// reap the intermediate child
int result;
qt_safe_waitpid(childPid, &result, 0);
bool success = (startResult == 0); // nothing written -> no error
if (success && pid) {
pid_t actualPid;
if (qt_safe_read(pidPipe[0], &actualPid, sizeof(pid_t)) != sizeof(pid_t))
actualPid = 0; // this shouldn't happen!
*pid = actualPid;
} else if (!success) {
if (pid)
*pid = -1;
QString msg;
if (startResult == sizeof(childStatus))
msg = QLatin1StringView(childStatus.function) + qt_error_string(childStatus.code);
setErrorAndEmit(QProcess::FailedToStart, msg);
}
return success;
}
#endif // QT_CONFIG(process)
QT_END_NAMESPACE
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