2b1e986572
Both poll(2) and ppoll(2) will return EINVAL if the nfds function argument is larger than the max files per process resource limit. Prevent this by limiting the max number entries in the pfds[] array to the RLIMIT_NOFILE soft limit.
242 lines
6.7 KiB
C
242 lines
6.7 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 2013-2015 Todd C. Miller <Todd.Miller@sudo.ws>
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*
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* Permission to use, copy, modify, and 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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* This is an open source non-commercial project. Dear PVS-Studio, please check it.
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* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
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*/
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#include <config.h>
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#include <sys/types.h>
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#include <sys/resource.h>
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#include <stdio.h>
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#include <stdlib.h>
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#ifdef HAVE_STDBOOL_H
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# include <stdbool.h>
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#else
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# include "compat/stdbool.h"
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#endif /* HAVE_STDBOOL_H */
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#ifdef HAVE_STRING_H
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# include <string.h>
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_STRINGS_H
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# include <strings.h>
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#endif /* HAVE_STRINGS_H */
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#include <time.h>
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#include <unistd.h>
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#include <errno.h>
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#include <poll.h>
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#include "sudo_compat.h"
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#include "sudo_util.h"
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#include "sudo_fatal.h"
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#include "sudo_debug.h"
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#include "sudo_event.h"
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int
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sudo_ev_base_alloc_impl(struct sudo_event_base *base)
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{
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int i;
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debug_decl(sudo_ev_base_alloc_impl, SUDO_DEBUG_EVENT);
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base->pfd_high = -1;
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base->pfd_max = 32;
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base->pfds = reallocarray(NULL, base->pfd_max, sizeof(struct pollfd));
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if (base->pfds == NULL) {
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sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
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"%s: unable to allocate %d pollfds", __func__, base->pfd_max);
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base->pfd_max = 0;
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debug_return_int(-1);
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}
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for (i = 0; i < base->pfd_max; i++) {
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base->pfds[i].fd = -1;
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}
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debug_return_int(0);
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}
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void
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sudo_ev_base_free_impl(struct sudo_event_base *base)
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{
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debug_decl(sudo_ev_base_free_impl, SUDO_DEBUG_EVENT);
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free(base->pfds);
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debug_return;
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}
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int
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sudo_ev_add_impl(struct sudo_event_base *base, struct sudo_event *ev)
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{
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static int nofile_max = -1;
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struct pollfd *pfd;
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debug_decl(sudo_ev_add_impl, SUDO_DEBUG_EVENT);
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if (nofile_max == -1) {
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struct rlimit rlim;
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if (getrlimit(RLIMIT_NOFILE, &rlim) == 0) {
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nofile_max = rlim.rlim_cur;
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}
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}
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/* If out of space in pfds array, realloc. */
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if (base->pfd_free == base->pfd_max) {
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struct pollfd *pfds;
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int i, new_max;
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/* Don't allow pfd_max to go over RLIM_NOFILE */
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new_max = base->pfd_max * 2;
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if (new_max > nofile_max)
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new_max = nofile_max;
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if (base->pfd_free == new_max) {
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sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
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"%s: out of fds (max %d)", __func__, nofile_max);
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debug_return_int(-1);
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}
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sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
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"%s: pfd_max %d -> %d", __func__, base->pfd_max, new_max);
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pfds = reallocarray(base->pfds, new_max, sizeof(struct pollfd));
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if (pfds == NULL) {
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sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
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"%s: unable to allocate %d pollfds", __func__, new_max);
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debug_return_int(-1);
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}
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base->pfds = pfds;
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base->pfd_max = new_max;
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for (i = base->pfd_free; i < base->pfd_max; i++) {
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base->pfds[i].fd = -1;
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}
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}
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/* Fill in pfd entry. */
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sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
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"%s: choosing free slot %d", __func__, base->pfd_free);
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ev->pfd_idx = base->pfd_free;
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pfd = &base->pfds[ev->pfd_idx];
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pfd->fd = ev->fd;
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pfd->events = 0;
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if (ISSET(ev->events, SUDO_EV_READ))
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pfd->events |= POLLIN;
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if (ISSET(ev->events, SUDO_EV_WRITE))
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pfd->events |= POLLOUT;
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/* Update pfd_high and pfd_free. */
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if (ev->pfd_idx > base->pfd_high)
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base->pfd_high = ev->pfd_idx;
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for (;;) {
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if (++base->pfd_free == base->pfd_max)
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break;
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if (base->pfds[base->pfd_free].fd == -1)
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break;
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}
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debug_return_int(0);
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}
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int
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sudo_ev_del_impl(struct sudo_event_base *base, struct sudo_event *ev)
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{
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debug_decl(sudo_ev_del_impl, SUDO_DEBUG_EVENT);
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/* Mark pfd entry unused, add to free list and adjust high slot. */
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base->pfds[ev->pfd_idx].fd = -1;
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if (ev->pfd_idx < base->pfd_free) {
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base->pfd_free = ev->pfd_idx;
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sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
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"%s: new free slot %d", __func__, base->pfd_free);
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}
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while (base->pfd_high >= 0 && base->pfds[base->pfd_high].fd == -1)
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base->pfd_high--;
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debug_return_int(0);
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}
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#ifdef HAVE_PPOLL
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static int
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sudo_ev_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timo)
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{
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return ppoll(fds, nfds, timo, NULL);
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}
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#else
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static int
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sudo_ev_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timo)
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{
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const int timeout =
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timo ? (timo->tv_sec * 1000) + (timo->tv_nsec / 1000000) : -1;
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return poll(fds, nfds, timeout);
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}
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#endif /* HAVE_PPOLL */
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int
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sudo_ev_scan_impl(struct sudo_event_base *base, int flags)
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{
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struct timespec now, ts, *timeout;
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struct sudo_event *ev;
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int nready;
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debug_decl(sudo_ev_scan_impl, SUDO_DEBUG_EVENT);
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if ((ev = TAILQ_FIRST(&base->timeouts)) != NULL) {
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sudo_gettime_mono(&now);
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sudo_timespecsub(&ev->timeout, &now, &ts);
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if (ts.tv_sec < 0)
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sudo_timespecclear(&ts);
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timeout = &ts;
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} else {
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if (ISSET(flags, SUDO_EVLOOP_NONBLOCK)) {
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sudo_timespecclear(&ts);
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timeout = &ts;
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} else {
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timeout = NULL;
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}
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}
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nready = sudo_ev_poll(base->pfds, base->pfd_high + 1, timeout);
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switch (nready) {
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case -1:
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/* Error: EINTR (signal) or EINVAL (nfds > RLIMIT_NOFILE) */
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sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
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"sudo_ev_poll");
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debug_return_int(-1);
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case 0:
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/* Front end will activate timeout events. */
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: timeout", __func__);
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break;
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default:
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/* Activate each I/O event that fired. */
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: %d fds ready", __func__,
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nready);
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TAILQ_FOREACH(ev, &base->events, entries) {
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if (ev->pfd_idx != -1 && base->pfds[ev->pfd_idx].revents) {
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int what = 0;
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if (base->pfds[ev->pfd_idx].revents & (POLLIN|POLLHUP|POLLNVAL|POLLERR))
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what |= (ev->events & SUDO_EV_READ);
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if (base->pfds[ev->pfd_idx].revents & (POLLOUT|POLLHUP|POLLNVAL|POLLERR))
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what |= (ev->events & SUDO_EV_WRITE);
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/* Make event active. */
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sudo_debug_printf(SUDO_DEBUG_DEBUG,
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"%s: polled fd %d, events %d, activating %p",
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__func__, ev->fd, what, ev);
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ev->revents = what;
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sudo_ev_activate(base, ev);
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}
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}
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break;
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}
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debug_return_int(nready);
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}
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