Revision control
++ // Copyright (C) 2016 The Qt Company Ltd.
++ // Copyright (C) 2016 Intel Corporation.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
++ // Qt-Security score:significant reason:default
++
++ #include <QtCore/private/qglobal_p.h>
++ #include <QtCore/qbasicatomic.h>
++ #include "qcore_unix_p.h"
++
++ #include <stdlib.h>
++
++ #ifdef __GLIBC__
++ # include <sys/syscall.h>
++ # include <pthread.h>
++ # include <unistd.h>
++ #endif
++
++ #ifdef Q_OS_DARWIN
++ #include <mach/mach_time.h>
++ #endif
++
++ QT_BEGIN_NAMESPACE
++
++ void qt_ignore_sigpipe() noexcept // noexcept: sigaction(2) is not a Posix Cancellation Point
++ {
++ // Set to ignore SIGPIPE once only.
++ Q_CONSTINIT static QBasicAtomicInt atom = Q_BASIC_ATOMIC_INITIALIZER(0);
++ if (!atom.loadRelaxed()) {
++ // More than one thread could turn off SIGPIPE at the same time
++ // But that's acceptable because they all would be doing the same
++ // action
++ struct sigaction noaction = {};
++ noaction.sa_handler = SIG_IGN;
++ ::sigaction(SIGPIPE, &noaction, nullptr);
++ atom.storeRelaxed(1);
++ }
++ }
++
++ QByteArray qt_readlink(const char *path)
++ {
++ #ifndef PATH_MAX
++ // suitably large value that won't consume too much memory
++ # define PATH_MAX 1024*1024
++ #endif
++
++ QByteArray buf(256, Qt::Uninitialized);
++
++ ssize_t len = ::readlink(path, buf.data(), buf.size());
++ while (len == buf.size()) {
++ // readlink(2) will fill our buffer and not necessarily terminate with NUL;
++ if (buf.size() >= PATH_MAX) {
++ errno = ENAMETOOLONG;
++ return QByteArray();
++ }
++
++ // double the size and try again
++ buf.resize(buf.size() * 2);
++ len = ::readlink(path, buf.data(), buf.size());
++ }
++
++ if (len == -1)
++ return QByteArray();
++
++ buf.resize(len);
++ return buf;
++ }
++
++ #if defined(Q_PROCESSOR_X86_32) && defined(__GLIBC__)
++ # if !__GLIBC_PREREQ(2, 22)
++ // glibc prior to release 2.22 had a bug that suppresses the third argument to
++ // open() / open64() / openat(), causing file creation with O_TMPFILE to have
++ // the wrong permissions. So we bypass the glibc implementation and go straight
++ // for the syscall. See
++ int qt_open64(const char *pathname, int flags, mode_t mode)
++ {
++ return syscall(SYS_open, pathname, flags | O_LARGEFILE, mode);
++ }
++ # endif
++ #endif
++
++ #ifndef QT_BOOTSTRAPPED
++
++ #if QT_CONFIG(poll_pollts)
++ # define ppoll pollts
++ #endif
++
++ [[maybe_unused]]
++ static inline int timespecToMillisecs(const struct timespec *ts)
++ {
++ using namespace std::chrono;
++ if (!ts)
++ return -1;
++ auto ms = ceil<milliseconds>(timespecToChrono<nanoseconds>(*ts));
++ return int(ms.count());
++ }
++
++ // defined in qpoll.cpp
++ int qt_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout_ts);
++
++ static inline int qt_ppoll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout_ts)
++ {
++ #if QT_CONFIG(poll_ppoll) || QT_CONFIG(poll_pollts)
++ return ::ppoll(fds, nfds, timeout_ts, nullptr);
++ #elif QT_CONFIG(poll_poll)
++ return ::poll(fds, nfds, timespecToMillisecs(timeout_ts));
++ #elif QT_CONFIG(poll_select)
++ return qt_poll(fds, nfds, timeout_ts);
++ #else
++ // configure.json reports an error when everything is not available
++ #endif
++ }
++
++
++ /*!
++ \internal
++
++ Behaves as close to POSIX poll(2) as practical but may be implemented
++ using select(2) where necessary. In that case, returns -1 and sets errno
++ to EINVAL if passed any descriptor greater than or equal to FD_SETSIZE.
++ */
++ int qt_safe_poll(struct pollfd *fds, nfds_t nfds, QDeadlineTimer deadline)
++ {
++ if (deadline.isForever()) {
++ // no timeout -> block forever
++ int ret;
++ QT_EINTR_LOOP(ret, qt_ppoll(fds, nfds, nullptr));
++ return ret;
++ }
++
++ using namespace std::chrono;
++ nanoseconds remaining = deadline.remainingTimeAsDuration();
++ // loop and recalculate the timeout as needed
++ do {
++ timespec ts = durationToTimespec(remaining);
++ const int ret = qt_ppoll(fds, nfds, &ts);
++ if (ret != -1 || errno != EINTR)
++ return ret;
++ remaining = deadline.remainingTimeAsDuration();
++ } while (remaining > 0ns);
++
++ return 0;
++ }
++
++ #endif // QT_BOOTSTRAPPED
++
++ QT_END_NAMESPACE