Repo created

TMessagesProj/jni/voip/webrtc/base/third_party/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.
+ */
+
+#include "config.h"
+
+#include <sys/types.h>
+#include <sys/resource.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#else
+#include <sys/_libevent_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 (evutil_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);
+}