119 lines
2.6 KiB
C
119 lines
2.6 KiB
C
/* dnsmasq is Copyright (c) 2000-2024 Simon Kelley
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 dated June, 1991, or
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(at your option) version 3 dated 29 June, 2007.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "dnsmasq.h"
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/* Wrapper for poll(). Allocates and extends array of struct pollfds,
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keeps them in fd order so that we can set and test conditions on
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fd using a simple but efficient binary chop. */
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/* poll_reset()
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poll_listen(fd, event)
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.
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.
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poll_listen(fd, event);
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hits = do_poll(timeout);
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if (poll_check(fd, event)
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.
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.
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if (poll_check(fd, event)
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.
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.
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event is OR of POLLIN, POLLOUT, POLLERR, etc
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*/
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static struct pollfd *pollfds = NULL;
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static nfds_t nfds, arrsize = 0;
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/* Binary search. Returns either the pollfd with fd, or
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if the fd doesn't match, or return equals nfds, the entry
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to the left of which a new record should be inserted. */
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static nfds_t fd_search(int fd)
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{
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nfds_t left, right, mid;
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if ((right = nfds) == 0)
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return 0;
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left = 0;
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while (1)
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{
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if (right == left + 1)
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return (pollfds[left].fd >= fd) ? left : right;
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mid = (left + right)/2;
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if (pollfds[mid].fd > fd)
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right = mid;
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else
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left = mid;
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}
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}
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void poll_reset(void)
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{
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nfds = 0;
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}
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int do_poll(int timeout)
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{
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return poll(pollfds, nfds, timeout);
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}
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int poll_check(int fd, short event)
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{
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nfds_t i = fd_search(fd);
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if (i < nfds && pollfds[i].fd == fd)
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return pollfds[i].revents & event;
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return 0;
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}
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void poll_listen(int fd, short event)
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{
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nfds_t i = fd_search(fd);
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if (i < nfds && pollfds[i].fd == fd)
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pollfds[i].events |= event;
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else
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{
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if (arrsize == nfds)
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{
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/* Array too small, extend. */
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struct pollfd *new;
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arrsize = (arrsize == 0) ? 64 : arrsize * 2;
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if (!(new = whine_realloc(pollfds, arrsize * sizeof(struct pollfd))))
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return;
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pollfds = new;
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}
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memmove(&pollfds[i+1], &pollfds[i], (nfds - i) * sizeof(struct pollfd));
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pollfds[i].fd = fd;
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pollfds[i].events = event;
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nfds++;
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}
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}
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