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-rw-r--r--libevent/devpoll.c417
1 files changed, 417 insertions, 0 deletions
diff --git a/libevent/devpoll.c b/libevent/devpoll.c
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--- /dev/null
+++ b/libevent/devpoll.c
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+/*
+ * Copyright 2000-2004 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <sys/types.h>
+#include <sys/resource.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#else
+#include <sys/_time.h>
+#endif
+#include <sys/queue.h>
+#include <sys/devpoll.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <assert.h>
+
+#include "event.h"
+#include "event-internal.h"
+#include "evsignal.h"
+#include "log.h"
+
+/* due to limitations in the devpoll interface, we need to keep track of
+ * all file descriptors outself.
+ */
+struct evdevpoll {
+ struct event *evread;
+ struct event *evwrite;
+};
+
+struct devpollop {
+ struct evdevpoll *fds;
+ int nfds;
+ struct pollfd *events;
+ int nevents;
+ int dpfd;
+ struct pollfd *changes;
+ int nchanges;
+};
+
+static void *devpoll_init (struct event_base *);
+static int devpoll_add (void *, struct event *);
+static int devpoll_del (void *, struct event *);
+static int devpoll_dispatch (struct event_base *, void *, struct timeval *);
+static void devpoll_dealloc (struct event_base *, void *);
+
+const struct eventop devpollops = {
+ "devpoll",
+ devpoll_init,
+ devpoll_add,
+ devpoll_del,
+ devpoll_dispatch,
+ devpoll_dealloc,
+ 1 /* need reinit */
+};
+
+#define NEVENT 32000
+
+static int
+devpoll_commit(struct devpollop *devpollop)
+{
+ /*
+ * Due to a bug in Solaris, we have to use pwrite with an offset of 0.
+ * Write is limited to 2GB of data, until it will fail.
+ */
+ if (pwrite(devpollop->dpfd, devpollop->changes,
+ sizeof(struct pollfd) * devpollop->nchanges, 0) == -1)
+ return(-1);
+
+ devpollop->nchanges = 0;
+ return(0);
+}
+
+static int
+devpoll_queue(struct devpollop *devpollop, int fd, int events) {
+ struct pollfd *pfd;
+
+ if (devpollop->nchanges >= devpollop->nevents) {
+ /*
+ * Change buffer is full, must commit it to /dev/poll before
+ * adding more
+ */
+ if (devpoll_commit(devpollop) != 0)
+ return(-1);
+ }
+
+ pfd = &devpollop->changes[devpollop->nchanges++];
+ pfd->fd = fd;
+ pfd->events = events;
+ pfd->revents = 0;
+
+ return(0);
+}
+
+static void *
+devpoll_init(struct event_base *base)
+{
+ int dpfd, nfiles = NEVENT;
+ struct rlimit rl;
+ struct devpollop *devpollop;
+
+ /* Disable devpoll when this environment variable is set */
+ if (getenv("EVENT_NODEVPOLL"))
+ return (NULL);
+
+ if (!(devpollop = calloc(1, sizeof(struct devpollop))))
+ return (NULL);
+
+ if (getrlimit(RLIMIT_NOFILE, &rl) == 0 &&
+ rl.rlim_cur != RLIM_INFINITY)
+ nfiles = rl.rlim_cur;
+
+ /* Initialize the kernel queue */
+ if ((dpfd = open("/dev/poll", O_RDWR)) == -1) {
+ event_warn("open: /dev/poll");
+ free(devpollop);
+ return (NULL);
+ }
+
+ devpollop->dpfd = dpfd;
+
+ /* Initialize fields */
+ devpollop->events = calloc(nfiles, sizeof(struct pollfd));
+ if (devpollop->events == NULL) {
+ free(devpollop);
+ close(dpfd);
+ return (NULL);
+ }
+ devpollop->nevents = nfiles;
+
+ devpollop->fds = calloc(nfiles, sizeof(struct evdevpoll));
+ if (devpollop->fds == NULL) {
+ free(devpollop->events);
+ free(devpollop);
+ close(dpfd);
+ return (NULL);
+ }
+ devpollop->nfds = nfiles;
+
+ devpollop->changes = calloc(nfiles, sizeof(struct pollfd));
+ if (devpollop->changes == NULL) {
+ free(devpollop->fds);
+ free(devpollop->events);
+ free(devpollop);
+ close(dpfd);
+ return (NULL);
+ }
+
+ evsignal_init(base);
+
+ return (devpollop);
+}
+
+static int
+devpoll_recalc(struct event_base *base, void *arg, int max)
+{
+ struct devpollop *devpollop = arg;
+
+ if (max >= devpollop->nfds) {
+ struct evdevpoll *fds;
+ int nfds;
+
+ nfds = devpollop->nfds;
+ while (nfds <= max)
+ nfds <<= 1;
+
+ fds = realloc(devpollop->fds, nfds * sizeof(struct evdevpoll));
+ if (fds == NULL) {
+ event_warn("realloc");
+ return (-1);
+ }
+ devpollop->fds = fds;
+ memset(fds + devpollop->nfds, 0,
+ (nfds - devpollop->nfds) * sizeof(struct evdevpoll));
+ devpollop->nfds = nfds;
+ }
+
+ return (0);
+}
+
+static int
+devpoll_dispatch(struct event_base *base, void *arg, struct timeval *tv)
+{
+ struct devpollop *devpollop = arg;
+ struct pollfd *events = devpollop->events;
+ struct dvpoll dvp;
+ struct evdevpoll *evdp;
+ int i, res, timeout = -1;
+
+ if (devpollop->nchanges)
+ devpoll_commit(devpollop);
+
+ if (tv != NULL)
+ timeout = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;
+
+ dvp.dp_fds = devpollop->events;
+ dvp.dp_nfds = devpollop->nevents;
+ dvp.dp_timeout = timeout;
+
+ res = ioctl(devpollop->dpfd, DP_POLL, &dvp);
+
+ if (res == -1) {
+ if (errno != EINTR) {
+ event_warn("ioctl: DP_POLL");
+ return (-1);
+ }
+
+ evsignal_process(base);
+ return (0);
+ } else if (base->sig.evsignal_caught) {
+ evsignal_process(base);
+ }
+
+ event_debug(("%s: devpoll_wait reports %d", __func__, res));
+
+ for (i = 0; i < res; i++) {
+ int which = 0;
+ int what = events[i].revents;
+ struct event *evread = NULL, *evwrite = NULL;
+
+ assert(events[i].fd < devpollop->nfds);
+ evdp = &devpollop->fds[events[i].fd];
+
+ if (what & POLLHUP)
+ what |= POLLIN | POLLOUT;
+ else if (what & POLLERR)
+ what |= POLLIN | POLLOUT;
+
+ if (what & POLLIN) {
+ evread = evdp->evread;
+ which |= EV_READ;
+ }
+
+ if (what & POLLOUT) {
+ evwrite = evdp->evwrite;
+ which |= EV_WRITE;
+ }
+
+ if (!which)
+ continue;
+
+ if (evread != NULL && !(evread->ev_events & EV_PERSIST))
+ event_del(evread);
+ if (evwrite != NULL && evwrite != evread &&
+ !(evwrite->ev_events & EV_PERSIST))
+ event_del(evwrite);
+
+ if (evread != NULL)
+ event_active(evread, EV_READ, 1);
+ if (evwrite != NULL)
+ event_active(evwrite, EV_WRITE, 1);
+ }
+
+ return (0);
+}
+
+
+static int
+devpoll_add(void *arg, struct event *ev)
+{
+ struct devpollop *devpollop = arg;
+ struct evdevpoll *evdp;
+ int fd, events;
+
+ if (ev->ev_events & EV_SIGNAL)
+ return (evsignal_add(ev));
+
+ fd = ev->ev_fd;
+ if (fd >= devpollop->nfds) {
+ /* Extend the file descriptor array as necessary */
+ if (devpoll_recalc(ev->ev_base, devpollop, fd) == -1)
+ return (-1);
+ }
+ evdp = &devpollop->fds[fd];
+
+ /*
+ * It's not necessary to OR the existing read/write events that we
+ * are currently interested in with the new event we are adding.
+ * The /dev/poll driver ORs any new events with the existing events
+ * that it has cached for the fd.
+ */
+
+ events = 0;
+ if (ev->ev_events & EV_READ) {
+ if (evdp->evread && evdp->evread != ev) {
+ /* There is already a different read event registered */
+ return(-1);
+ }
+ events |= POLLIN;
+ }
+
+ if (ev->ev_events & EV_WRITE) {
+ if (evdp->evwrite && evdp->evwrite != ev) {
+ /* There is already a different write event registered */
+ return(-1);
+ }
+ events |= POLLOUT;
+ }
+
+ if (devpoll_queue(devpollop, fd, events) != 0)
+ return(-1);
+
+ /* Update events responsible */
+ if (ev->ev_events & EV_READ)
+ evdp->evread = ev;
+ if (ev->ev_events & EV_WRITE)
+ evdp->evwrite = ev;
+
+ return (0);
+}
+
+static int
+devpoll_del(void *arg, struct event *ev)
+{
+ struct devpollop *devpollop = arg;
+ struct evdevpoll *evdp;
+ int fd, events;
+ int needwritedelete = 1, needreaddelete = 1;
+
+ if (ev->ev_events & EV_SIGNAL)
+ return (evsignal_del(ev));
+
+ fd = ev->ev_fd;
+ if (fd >= devpollop->nfds)
+ return (0);
+ evdp = &devpollop->fds[fd];
+
+ events = 0;
+ if (ev->ev_events & EV_READ)
+ events |= POLLIN;
+ if (ev->ev_events & EV_WRITE)
+ events |= POLLOUT;
+
+ /*
+ * The only way to remove an fd from the /dev/poll monitored set is
+ * to use POLLREMOVE by itself. This removes ALL events for the fd
+ * provided so if we care about two events and are only removing one
+ * we must re-add the other event after POLLREMOVE.
+ */
+
+ if (devpoll_queue(devpollop, fd, POLLREMOVE) != 0)
+ return(-1);
+
+ if ((events & (POLLIN|POLLOUT)) != (POLLIN|POLLOUT)) {
+ /*
+ * We're not deleting all events, so we must resubmit the
+ * event that we are still interested in if one exists.
+ */
+
+ if ((events & POLLIN) && evdp->evwrite != NULL) {
+ /* Deleting read, still care about write */
+ devpoll_queue(devpollop, fd, POLLOUT);
+ needwritedelete = 0;
+ } else if ((events & POLLOUT) && evdp->evread != NULL) {
+ /* Deleting write, still care about read */
+ devpoll_queue(devpollop, fd, POLLIN);
+ needreaddelete = 0;
+ }
+ }
+
+ if (needreaddelete)
+ evdp->evread = NULL;
+ if (needwritedelete)
+ evdp->evwrite = NULL;
+
+ return (0);
+}
+
+static void
+devpoll_dealloc(struct event_base *base, void *arg)
+{
+ struct devpollop *devpollop = arg;
+
+ evsignal_dealloc(base);
+ if (devpollop->fds)
+ free(devpollop->fds);
+ if (devpollop->events)
+ free(devpollop->events);
+ if (devpollop->changes)
+ free(devpollop->changes);
+ if (devpollop->dpfd >= 0)
+ close(devpollop->dpfd);
+
+ memset(devpollop, 0, sizeof(struct devpollop));
+ free(devpollop);
+}
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