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Diffstat (limited to 'src/corelib/kernel/qpoll.cpp')
| -rw-r--r-- | src/corelib/kernel/qpoll.cpp | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/corelib/kernel/qpoll.cpp b/src/corelib/kernel/qpoll.cpp new file mode 100644 index 0000000000..8e93c4d363 --- /dev/null +++ b/src/corelib/kernel/qpoll.cpp @@ -0,0 +1,226 @@ +/**************************************************************************** +** +** Copyright (C) 2016 The Qt Company Ltd. +** 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. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qcore_unix_p.h" + +QT_BEGIN_NAMESPACE + +#define QT_POLL_READ_MASK (POLLIN | POLLRDNORM) +#define QT_POLL_WRITE_MASK (POLLOUT | POLLWRNORM | POLLWRBAND) +#define QT_POLL_EXCEPT_MASK (POLLPRI | POLLRDBAND) +#define QT_POLL_ERROR_MASK (POLLERR | POLLNVAL) +#define QT_POLL_EVENTS_MASK (QT_POLL_READ_MASK | QT_POLL_WRITE_MASK | QT_POLL_EXCEPT_MASK) + +static inline int qt_poll_prepare(struct pollfd *fds, nfds_t nfds, + fd_set *read_fds, fd_set *write_fds, fd_set *except_fds) +{ + int max_fd = -1; + + FD_ZERO(read_fds); + FD_ZERO(write_fds); + FD_ZERO(except_fds); + + for (nfds_t i = 0; i < nfds; i++) { + if (fds[i].fd >= FD_SETSIZE) { + errno = EINVAL; + return -1; + } + + if ((fds[i].fd < 0) || (fds[i].revents & QT_POLL_ERROR_MASK)) + continue; + + if (fds[i].events & QT_POLL_READ_MASK) + FD_SET(fds[i].fd, read_fds); + + if (fds[i].events & QT_POLL_WRITE_MASK) + FD_SET(fds[i].fd, write_fds); + + if (fds[i].events & QT_POLL_EXCEPT_MASK) + FD_SET(fds[i].fd, except_fds); + + if (fds[i].events & QT_POLL_EVENTS_MASK) + max_fd = qMax(max_fd, fds[i].fd); + } + + return max_fd + 1; +} + +static inline void qt_poll_examine_ready_read(struct pollfd &pfd) +{ + int res; + char data; + + EINTR_LOOP(res, ::recv(pfd.fd, &data, sizeof(data), MSG_PEEK)); + const int error = (res < 0) ? errno : 0; + + if (res == 0) { + pfd.revents |= POLLHUP; + } else if (res > 0 || error == ENOTSOCK || error == ENOTCONN) { + pfd.revents |= QT_POLL_READ_MASK & pfd.events; + } else { + switch (error) { + case ESHUTDOWN: + case ECONNRESET: + case ECONNABORTED: + case ENETRESET: + pfd.revents |= POLLHUP; + break; + default: + pfd.revents |= POLLERR; + break; + } + } +} + +static inline int qt_poll_sweep(struct pollfd *fds, nfds_t nfds, + fd_set *read_fds, fd_set *write_fds, fd_set *except_fds) +{ + int result = 0; + + for (nfds_t i = 0; i < nfds; i++) { + if (fds[i].fd < 0) + continue; + + if (FD_ISSET(fds[i].fd, read_fds)) + qt_poll_examine_ready_read(fds[i]); + + if (FD_ISSET(fds[i].fd, write_fds)) + fds[i].revents |= QT_POLL_WRITE_MASK & fds[i].events; + + if (FD_ISSET(fds[i].fd, except_fds)) + fds[i].revents |= QT_POLL_EXCEPT_MASK & fds[i].events; + + if (fds[i].revents != 0) + result++; + } + + return result; +} + +static inline bool qt_poll_is_bad_fd(int fd) +{ + int ret; + EINTR_LOOP(ret, fcntl(fd, F_GETFD)); + return (ret == -1 && errno == EBADF); +} + +static inline int qt_poll_mark_bad_fds(struct pollfd *fds, const nfds_t nfds) +{ + int n_marked = 0; + + for (nfds_t i = 0; i < nfds; i++) { + if (fds[i].fd < 0) + continue; + + if (fds[i].revents & QT_POLL_ERROR_MASK) + continue; + + if (qt_poll_is_bad_fd(fds[i].fd)) { + fds[i].revents |= POLLNVAL; + n_marked++; + } + } + + return n_marked; +} + +int qt_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout_ts) +{ + if (!fds && nfds) { + errno = EFAULT; + return -1; + } + + fd_set read_fds, write_fds, except_fds; + struct timeval tv, *ptv = 0; + + if (timeout_ts) { + tv = timespecToTimeval(*timeout_ts); + ptv = &tv; + } + + int n_bad_fds = 0; + + for (nfds_t i = 0; i < nfds; i++) { + fds[i].revents = 0; + + if (fds[i].fd < 0) + continue; + + if (fds[i].events & QT_POLL_EVENTS_MASK) + continue; + + if (qt_poll_is_bad_fd(fds[i].fd)) { + // Mark bad file descriptors that have no event flags set + // here, as we won't be passing them to select below and therefore + // need to do the check ourselves + fds[i].revents = POLLNVAL; + n_bad_fds++; + } + } + + forever { + const int max_fd = qt_poll_prepare(fds, nfds, &read_fds, &write_fds, &except_fds); + + if (max_fd < 0) + return max_fd; + + if (n_bad_fds > 0) { + tv.tv_sec = 0; + tv.tv_usec = 0; + ptv = &tv; + } + + const int ret = ::select(max_fd, &read_fds, &write_fds, &except_fds, ptv); + + if (ret == 0) + return n_bad_fds; + + if (ret > 0) + return qt_poll_sweep(fds, nfds, &read_fds, &write_fds, &except_fds); + + if (errno != EBADF) + return -1; + + // We have at least one bad file descriptor that we waited on, find out which and try again + n_bad_fds += qt_poll_mark_bad_fds(fds, nfds); + } +} + +QT_END_NAMESPACE |