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90452c8b69
If the underlying system's select() returns bits that were not in the request set, our ppoll() implementation can return revents for events not requested, which can apparently cause a hang. Only return revents for activity in the requested event set. bz#3416, analysis and fix by yaroslav.kuzmin at vmssoftware com, ok djm@
130 lines
3.5 KiB
C
130 lines
3.5 KiB
C
/*
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* Copyright (c) 2004, 2005, 2007 Darren Tucker (dtucker at zip com au).
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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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#include "includes.h"
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#if !defined(HAVE_PPOLL) || !defined(HAVE_POLL) || defined(BROKEN_POLL)
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#include <sys/types.h>
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#include <sys/time.h>
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#ifdef HAVE_SYS_PARAM_H
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# include <sys/param.h>
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#endif
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#ifdef HAVE_SYS_SELECT_H
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# include <sys/select.h>
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#endif
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#include <errno.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "bsd-poll.h"
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#if !defined(HAVE_PPOLL) || defined(BROKEN_POLL)
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/*
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* A minimal implementation of ppoll(2), built on top of pselect(2).
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*
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* Only supports POLLIN, POLLOUT and POLLPRI flags in pfd.events and
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* revents. Notably POLLERR, POLLHUP and POLLNVAL are not supported.
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*
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* Supports pfd.fd = -1 meaning "unused" although it's not standard.
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*/
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int
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ppoll(struct pollfd *fds, nfds_t nfds, const struct timespec *tmoutp,
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const sigset_t *sigmask)
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{
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nfds_t i;
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int saved_errno, ret, fd, maxfd = 0;
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fd_set *readfds = NULL, *writefds = NULL, *exceptfds = NULL;
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size_t nmemb;
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for (i = 0; i < nfds; i++) {
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fd = fds[i].fd;
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if (fd != -1 && fd >= FD_SETSIZE) {
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errno = EINVAL;
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return -1;
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}
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maxfd = MAX(maxfd, fd);
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}
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nmemb = howmany(maxfd + 1 , NFDBITS);
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if ((readfds = calloc(nmemb, sizeof(fd_mask))) == NULL ||
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(writefds = calloc(nmemb, sizeof(fd_mask))) == NULL ||
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(exceptfds = calloc(nmemb, sizeof(fd_mask))) == NULL) {
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saved_errno = ENOMEM;
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ret = -1;
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goto out;
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}
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/* populate event bit vectors for the events we're interested in */
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for (i = 0; i < nfds; i++) {
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fd = fds[i].fd;
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if (fd == -1)
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continue;
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if (fds[i].events & POLLIN)
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FD_SET(fd, readfds);
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if (fds[i].events & POLLOUT)
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FD_SET(fd, writefds);
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if (fds[i].events & POLLPRI)
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FD_SET(fd, exceptfds);
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}
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ret = pselect(maxfd + 1, readfds, writefds, exceptfds, tmoutp, sigmask);
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saved_errno = errno;
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/* scan through select results and set poll() flags */
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for (i = 0; i < nfds; i++) {
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fd = fds[i].fd;
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fds[i].revents = 0;
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if (fd == -1)
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continue;
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if ((fds[i].events & POLLIN) && FD_ISSET(fd, readfds))
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fds[i].revents |= POLLIN;
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if ((fds[i].events & POLLOUT) && FD_ISSET(fd, writefds))
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fds[i].revents |= POLLOUT;
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if ((fds[i].events & POLLPRI) && FD_ISSET(fd, exceptfds))
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fds[i].revents |= POLLPRI;
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}
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out:
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free(readfds);
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free(writefds);
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free(exceptfds);
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if (ret == -1)
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errno = saved_errno;
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return ret;
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}
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#endif /* !HAVE_PPOLL || BROKEN_POLL */
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#if !defined(HAVE_POLL) || defined(BROKEN_POLL)
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int
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poll(struct pollfd *fds, nfds_t nfds, int timeout)
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{
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struct timespec ts, *tsp = NULL;
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/* poll timeout is msec, ppoll is timespec (sec + nsec) */
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if (timeout >= 0) {
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ts.tv_sec = timeout / 1000;
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ts.tv_nsec = (timeout % 1000) * 1000000;
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tsp = &ts;
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}
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return ppoll(fds, nfds, tsp, NULL);
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}
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#endif /* !HAVE_POLL || BROKEN_POLL */
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#endif /* !HAVE_PPOLL || !HAVE_POLL || BROKEN_POLL */
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