openssh/openbsd-compat/bsd-poll.c
Pierre Ossman d9df5689c2
Avoid assuming layout of fd_set
POSIX doesn't specify the internal layout of the fd_set object, so let's
not assume it is just a bit mask. This increases compatibility with
systems that have a different layout.

The assumption is also worthless as we already refuse to use file
descriptors over FD_SETSIZE anyway. Meaning that the default size of
fd_set is quite sufficient.
2022-11-08 19:33:47 +11:00

116 lines
3.1 KiB
C

/*
* Copyright (c) 2004, 2005, 2007 Darren Tucker (dtucker at zip com au).
*
* 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.
*/
#include "includes.h"
#if !defined(HAVE_PPOLL) || !defined(HAVE_POLL) || defined(BROKEN_POLL)
#include <sys/types.h>
#include <sys/time.h>
#ifdef HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif
#ifdef HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include "bsd-poll.h"
#if !defined(HAVE_PPOLL) || defined(BROKEN_POLL)
/*
* A minimal implementation of ppoll(2), built on top of pselect(2).
*
* Only supports POLLIN, POLLOUT and POLLPRI flags in pfd.events and
* revents. Notably POLLERR, POLLHUP and POLLNVAL are not supported.
*
* Supports pfd.fd = -1 meaning "unused" although it's not standard.
*/
int
ppoll(struct pollfd *fds, nfds_t nfds, const struct timespec *tmoutp,
const sigset_t *sigmask)
{
nfds_t i;
int ret, fd, maxfd = 0;
fd_set readfds, writefds, exceptfds;
for (i = 0; i < nfds; i++) {
fd = fds[i].fd;
if (fd != -1 && fd >= FD_SETSIZE) {
errno = EINVAL;
return -1;
}
maxfd = MAX(maxfd, fd);
}
/* populate event bit vectors for the events we're interested in */
FD_ZERO(&readfds);
FD_ZERO(&writefds);
FD_ZERO(&exceptfds);
for (i = 0; i < nfds; i++) {
fd = fds[i].fd;
if (fd == -1)
continue;
if (fds[i].events & POLLIN)
FD_SET(fd, &readfds);
if (fds[i].events & POLLOUT)
FD_SET(fd, &writefds);
if (fds[i].events & POLLPRI)
FD_SET(fd, &exceptfds);
}
ret = pselect(maxfd + 1, &readfds, &writefds, &exceptfds, tmoutp, sigmask);
/* scan through select results and set poll() flags */
for (i = 0; i < nfds; i++) {
fd = fds[i].fd;
fds[i].revents = 0;
if (fd == -1)
continue;
if ((fds[i].events & POLLIN) && FD_ISSET(fd, &readfds))
fds[i].revents |= POLLIN;
if ((fds[i].events & POLLOUT) && FD_ISSET(fd, &writefds))
fds[i].revents |= POLLOUT;
if ((fds[i].events & POLLPRI) && FD_ISSET(fd, &exceptfds))
fds[i].revents |= POLLPRI;
}
return ret;
}
#endif /* !HAVE_PPOLL || BROKEN_POLL */
#if !defined(HAVE_POLL) || defined(BROKEN_POLL)
int
poll(struct pollfd *fds, nfds_t nfds, int timeout)
{
struct timespec ts, *tsp = NULL;
/* poll timeout is msec, ppoll is timespec (sec + nsec) */
if (timeout >= 0) {
ts.tv_sec = timeout / 1000;
ts.tv_nsec = (timeout % 1000) * 1000000;
tsp = &ts;
}
return ppoll(fds, nfds, tsp, NULL);
}
#endif /* !HAVE_POLL || BROKEN_POLL */
#endif /* !HAVE_PPOLL || !HAVE_POLL || BROKEN_POLL */