4e3a47a4cb
Fix a race condition when do_sigchld, uloop_cancelled were set just before epoll_wait(timeout=-1), resulting the loop stuck in the syscall without noticing the events just happened Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com> Signed-off-by: Felix Fietkau <nbd@nbd.name>
108 lines
2.5 KiB
C
108 lines
2.5 KiB
C
/*
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* uloop - event loop implementation
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*
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* Copyright (C) 2010-2016 Felix Fietkau <nbd@openwrt.org>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/**
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* FIXME: uClibc < 0.9.30.3 does not define EPOLLRDHUP for Linux >= 2.6.17
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*/
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#ifndef EPOLLRDHUP
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#define EPOLLRDHUP 0x2000
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#endif
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static int uloop_init_pollfd(void)
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{
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if (poll_fd >= 0)
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return 0;
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poll_fd = epoll_create(32);
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if (poll_fd < 0)
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return -1;
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fcntl(poll_fd, F_SETFD, fcntl(poll_fd, F_GETFD) | FD_CLOEXEC);
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return 0;
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}
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static int register_poll(struct uloop_fd *fd, unsigned int flags)
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{
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struct epoll_event ev;
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int op = fd->registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
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memset(&ev, 0, sizeof(struct epoll_event));
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if (flags & ULOOP_READ)
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ev.events |= EPOLLIN | EPOLLRDHUP;
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if (flags & ULOOP_WRITE)
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ev.events |= EPOLLOUT;
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if (flags & ULOOP_EDGE_TRIGGER)
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ev.events |= EPOLLET;
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ev.data.fd = fd->fd;
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ev.data.ptr = fd;
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fd->flags = flags;
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return epoll_ctl(poll_fd, op, fd->fd, &ev);
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}
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static struct epoll_event events[ULOOP_MAX_EVENTS];
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static int __uloop_fd_delete(struct uloop_fd *sock)
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{
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sock->flags = 0;
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return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
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}
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static int uloop_fetch_events(int timeout)
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{
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int n, nfds;
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nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
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for (n = 0; n < nfds; ++n) {
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struct uloop_fd_event *cur = &cur_fds[n];
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struct uloop_fd *u = events[n].data.ptr;
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unsigned int ev = 0;
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cur->fd = u;
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if (!u)
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continue;
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if (events[n].events & (EPOLLERR|EPOLLHUP)) {
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u->error = true;
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if (!(u->flags & ULOOP_ERROR_CB))
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uloop_fd_delete(u);
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}
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if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP))) {
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cur->fd = NULL;
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continue;
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}
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if(events[n].events & EPOLLRDHUP)
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u->eof = true;
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if(events[n].events & EPOLLIN)
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ev |= ULOOP_READ;
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if(events[n].events & EPOLLOUT)
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ev |= ULOOP_WRITE;
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cur->events = ev;
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}
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return nfds;
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}
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