sudo/lib/util/event_poll.c

237 lines
6.6 KiB
C

/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2013-2015 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <sys/resource.h>
#include <limits.h>
#include <poll.h>
#include <stdlib.h>
#include <time.h>
#include <sudo_compat.h>
#include <sudo_util.h>
#include <sudo_fatal.h>
#include <sudo_debug.h>
#include <sudo_event.h>
#if defined(OPEN_MAX) && OPEN_MAX > 256
# define SUDO_OPEN_MAX OPEN_MAX
#else
# define SUDO_OPEN_MAX 256
#endif
int
sudo_ev_base_alloc_impl(struct sudo_event_base *base)
{
int i;
debug_decl(sudo_ev_base_alloc_impl, SUDO_DEBUG_EVENT);
base->pfd_high = -1;
base->pfd_max = 32;
base->pfds = reallocarray(NULL, (size_t)base->pfd_max, sizeof(struct pollfd));
if (base->pfds == NULL) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"%s: unable to allocate %d pollfds", __func__, base->pfd_max);
base->pfd_max = 0;
debug_return_int(-1);
}
for (i = 0; i < base->pfd_max; i++) {
base->pfds[i].fd = -1;
}
debug_return_int(0);
}
void
sudo_ev_base_free_impl(struct sudo_event_base *base)
{
debug_decl(sudo_ev_base_free_impl, SUDO_DEBUG_EVENT);
free(base->pfds);
debug_return;
}
int
sudo_ev_add_impl(struct sudo_event_base *base, struct sudo_event *ev)
{
static int nofile_max = -1;
struct pollfd *pfd;
debug_decl(sudo_ev_add_impl, SUDO_DEBUG_EVENT);
if (nofile_max == -1) {
struct rlimit rlim;
if (getrlimit(RLIMIT_NOFILE, &rlim) == 0) {
nofile_max = (int)rlim.rlim_cur;
} else {
nofile_max = SUDO_OPEN_MAX;
}
}
/* If out of space in pfds array, realloc. */
if (base->pfd_free == base->pfd_max) {
struct pollfd *pfds;
int i, new_max;
/* Don't allow pfd_max to go over RLIM_NOFILE */
new_max = base->pfd_max * 2;
if (new_max > nofile_max)
new_max = nofile_max;
if (base->pfd_free == new_max) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"%s: out of fds (max %d)", __func__, nofile_max);
debug_return_int(-1);
}
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"%s: pfd_max %d -> %d", __func__, base->pfd_max, new_max);
pfds = reallocarray(base->pfds, (size_t)new_max, sizeof(struct pollfd));
if (pfds == NULL) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
"%s: unable to allocate %d pollfds", __func__, new_max);
debug_return_int(-1);
}
base->pfds = pfds;
base->pfd_max = new_max;
for (i = base->pfd_free; i < base->pfd_max; i++) {
base->pfds[i].fd = -1;
}
}
/* Fill in pfd entry. */
sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
"%s: choosing free slot %d", __func__, base->pfd_free);
ev->pfd_idx = (short)base->pfd_free;
pfd = &base->pfds[ev->pfd_idx];
pfd->fd = ev->fd;
pfd->events = 0;
if (ISSET(ev->events, SUDO_EV_READ))
pfd->events |= POLLIN;
if (ISSET(ev->events, SUDO_EV_WRITE))
pfd->events |= POLLOUT;
/* Update pfd_high and pfd_free. */
if (ev->pfd_idx > base->pfd_high)
base->pfd_high = ev->pfd_idx;
for (;;) {
if (++base->pfd_free == base->pfd_max)
break;
if (base->pfds[base->pfd_free].fd == -1)
break;
}
debug_return_int(0);
}
int
sudo_ev_del_impl(struct sudo_event_base *base, struct sudo_event *ev)
{
debug_decl(sudo_ev_del_impl, SUDO_DEBUG_EVENT);
/* Mark pfd entry unused, add to free list and adjust high slot. */
base->pfds[ev->pfd_idx].fd = -1;
if (ev->pfd_idx < base->pfd_free) {
base->pfd_free = ev->pfd_idx;
sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
"%s: new free slot %d", __func__, base->pfd_free);
}
while (base->pfd_high >= 0 && base->pfds[base->pfd_high].fd == -1)
base->pfd_high--;
debug_return_int(0);
}
#ifdef HAVE_PPOLL
static int
sudo_ev_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timo)
{
return ppoll(fds, nfds, timo, NULL);
}
#else
static int
sudo_ev_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timo)
{
const int timeout =
timo ? (timo->tv_sec * 1000) + (timo->tv_nsec / 1000000) : -1;
return poll(fds, nfds, timeout);
}
#endif /* HAVE_PPOLL */
int
sudo_ev_scan_impl(struct sudo_event_base *base, unsigned int flags)
{
struct timespec now, ts, *timeout;
struct sudo_event *ev;
int nready;
debug_decl(sudo_ev_scan_impl, SUDO_DEBUG_EVENT);
if ((ev = TAILQ_FIRST(&base->timeouts)) != NULL) {
sudo_gettime_mono(&now);
sudo_timespecsub(&ev->timeout, &now, &ts);
if (ts.tv_sec < 0)
sudo_timespecclear(&ts);
timeout = &ts;
} else {
if (ISSET(flags, SUDO_EVLOOP_NONBLOCK)) {
sudo_timespecclear(&ts);
timeout = &ts;
} else {
timeout = NULL;
}
}
nready = sudo_ev_poll(base->pfds, (nfds_t)base->pfd_high + 1, timeout);
switch (nready) {
case -1:
/* Error: EINTR (signal) or EINVAL (nfds > RLIMIT_NOFILE) */
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,
"sudo_ev_poll");
break;
case 0:
/* Front end will activate timeout events. */
sudo_debug_printf(SUDO_DEBUG_INFO, "%s: timeout", __func__);
break;
default:
/* Activate each I/O event that fired. */
sudo_debug_printf(SUDO_DEBUG_INFO, "%s: %d fds ready", __func__,
nready);
TAILQ_FOREACH(ev, &base->events, entries) {
if (ev->pfd_idx != -1 && base->pfds[ev->pfd_idx].revents) {
int what = 0;
if (base->pfds[ev->pfd_idx].revents & (POLLIN|POLLHUP|POLLNVAL|POLLERR))
what |= (ev->events & SUDO_EV_READ);
if (base->pfds[ev->pfd_idx].revents & (POLLOUT|POLLHUP|POLLNVAL|POLLERR))
what |= (ev->events & SUDO_EV_WRITE);
/* Make event active. */
sudo_debug_printf(SUDO_DEBUG_DEBUG,
"%s: polled fd %d, events %d, activating %p",
__func__, ev->fd, what, ev);
ev->revents = (short)what;
sudo_ev_activate(base, ev);
}
}
break;
}
debug_return_int(nready);
}