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// 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