1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/third_party/libevent/devpoll.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,306 @@
1.4 +/*
1.5 + * Copyright 2000-2009 Niels Provos <provos@citi.umich.edu>
1.6 + * Copyright 2009-2012 Niels Provos and Nick Mathewson
1.7 + *
1.8 + * Redistribution and use in source and binary forms, with or without
1.9 + * modification, are permitted provided that the following conditions
1.10 + * are met:
1.11 + * 1. Redistributions of source code must retain the above copyright
1.12 + * notice, this list of conditions and the following disclaimer.
1.13 + * 2. Redistributions in binary form must reproduce the above copyright
1.14 + * notice, this list of conditions and the following disclaimer in the
1.15 + * documentation and/or other materials provided with the distribution.
1.16 + * 3. The name of the author may not be used to endorse or promote products
1.17 + * derived from this software without specific prior written permission.
1.18 + *
1.19 + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
1.20 + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1.21 + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
1.22 + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
1.23 + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
1.24 + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.25 + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.26 + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.27 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1.28 + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.29 + */
1.30 +#include "event2/event-config.h"
1.31 +
1.32 +#include <sys/types.h>
1.33 +#include <sys/resource.h>
1.34 +#ifdef _EVENT_HAVE_SYS_TIME_H
1.35 +#include <sys/time.h>
1.36 +#endif
1.37 +#include <sys/queue.h>
1.38 +#include <sys/devpoll.h>
1.39 +#include <signal.h>
1.40 +#include <stdio.h>
1.41 +#include <stdlib.h>
1.42 +#include <string.h>
1.43 +#include <unistd.h>
1.44 +#include <fcntl.h>
1.45 +#include <errno.h>
1.46 +
1.47 +#include "event2/event.h"
1.48 +#include "event2/event_struct.h"
1.49 +#include "event2/thread.h"
1.50 +#include "event-internal.h"
1.51 +#include "evsignal-internal.h"
1.52 +#include "log-internal.h"
1.53 +#include "evmap-internal.h"
1.54 +#include "evthread-internal.h"
1.55 +
1.56 +struct devpollop {
1.57 + struct pollfd *events;
1.58 + int nevents;
1.59 + int dpfd;
1.60 + struct pollfd *changes;
1.61 + int nchanges;
1.62 +};
1.63 +
1.64 +static void *devpoll_init(struct event_base *);
1.65 +static int devpoll_add(struct event_base *, int fd, short old, short events, void *);
1.66 +static int devpoll_del(struct event_base *, int fd, short old, short events, void *);
1.67 +static int devpoll_dispatch(struct event_base *, struct timeval *);
1.68 +static void devpoll_dealloc(struct event_base *);
1.69 +
1.70 +const struct eventop devpollops = {
1.71 + "devpoll",
1.72 + devpoll_init,
1.73 + devpoll_add,
1.74 + devpoll_del,
1.75 + devpoll_dispatch,
1.76 + devpoll_dealloc,
1.77 + 1, /* need reinit */
1.78 + EV_FEATURE_FDS|EV_FEATURE_O1,
1.79 + 0
1.80 +};
1.81 +
1.82 +#define NEVENT 32000
1.83 +
1.84 +static int
1.85 +devpoll_commit(struct devpollop *devpollop)
1.86 +{
1.87 + /*
1.88 + * Due to a bug in Solaris, we have to use pwrite with an offset of 0.
1.89 + * Write is limited to 2GB of data, until it will fail.
1.90 + */
1.91 + if (pwrite(devpollop->dpfd, devpollop->changes,
1.92 + sizeof(struct pollfd) * devpollop->nchanges, 0) == -1)
1.93 + return (-1);
1.94 +
1.95 + devpollop->nchanges = 0;
1.96 + return (0);
1.97 +}
1.98 +
1.99 +static int
1.100 +devpoll_queue(struct devpollop *devpollop, int fd, int events) {
1.101 + struct pollfd *pfd;
1.102 +
1.103 + if (devpollop->nchanges >= devpollop->nevents) {
1.104 + /*
1.105 + * Change buffer is full, must commit it to /dev/poll before
1.106 + * adding more
1.107 + */
1.108 + if (devpoll_commit(devpollop) != 0)
1.109 + return (-1);
1.110 + }
1.111 +
1.112 + pfd = &devpollop->changes[devpollop->nchanges++];
1.113 + pfd->fd = fd;
1.114 + pfd->events = events;
1.115 + pfd->revents = 0;
1.116 +
1.117 + return (0);
1.118 +}
1.119 +
1.120 +static void *
1.121 +devpoll_init(struct event_base *base)
1.122 +{
1.123 + int dpfd, nfiles = NEVENT;
1.124 + struct rlimit rl;
1.125 + struct devpollop *devpollop;
1.126 +
1.127 + if (!(devpollop = mm_calloc(1, sizeof(struct devpollop))))
1.128 + return (NULL);
1.129 +
1.130 + if (getrlimit(RLIMIT_NOFILE, &rl) == 0 &&
1.131 + rl.rlim_cur != RLIM_INFINITY)
1.132 + nfiles = rl.rlim_cur;
1.133 +
1.134 + /* Initialize the kernel queue */
1.135 + if ((dpfd = evutil_open_closeonexec("/dev/poll", O_RDWR, 0)) == -1) {
1.136 + event_warn("open: /dev/poll");
1.137 + mm_free(devpollop);
1.138 + return (NULL);
1.139 + }
1.140 +
1.141 + devpollop->dpfd = dpfd;
1.142 +
1.143 + /* Initialize fields */
1.144 + /* FIXME: allocating 'nfiles' worth of space here can be
1.145 + * expensive and unnecessary. See how epoll.c does it instead. */
1.146 + devpollop->events = mm_calloc(nfiles, sizeof(struct pollfd));
1.147 + if (devpollop->events == NULL) {
1.148 + mm_free(devpollop);
1.149 + close(dpfd);
1.150 + return (NULL);
1.151 + }
1.152 + devpollop->nevents = nfiles;
1.153 +
1.154 + devpollop->changes = mm_calloc(nfiles, sizeof(struct pollfd));
1.155 + if (devpollop->changes == NULL) {
1.156 + mm_free(devpollop->events);
1.157 + mm_free(devpollop);
1.158 + close(dpfd);
1.159 + return (NULL);
1.160 + }
1.161 +
1.162 + evsig_init(base);
1.163 +
1.164 + return (devpollop);
1.165 +}
1.166 +
1.167 +static int
1.168 +devpoll_dispatch(struct event_base *base, struct timeval *tv)
1.169 +{
1.170 + struct devpollop *devpollop = base->evbase;
1.171 + struct pollfd *events = devpollop->events;
1.172 + struct dvpoll dvp;
1.173 + int i, res, timeout = -1;
1.174 +
1.175 + if (devpollop->nchanges)
1.176 + devpoll_commit(devpollop);
1.177 +
1.178 + if (tv != NULL)
1.179 + timeout = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;
1.180 +
1.181 + dvp.dp_fds = devpollop->events;
1.182 + dvp.dp_nfds = devpollop->nevents;
1.183 + dvp.dp_timeout = timeout;
1.184 +
1.185 + EVBASE_RELEASE_LOCK(base, th_base_lock);
1.186 +
1.187 + res = ioctl(devpollop->dpfd, DP_POLL, &dvp);
1.188 +
1.189 + EVBASE_ACQUIRE_LOCK(base, th_base_lock);
1.190 +
1.191 + if (res == -1) {
1.192 + if (errno != EINTR) {
1.193 + event_warn("ioctl: DP_POLL");
1.194 + return (-1);
1.195 + }
1.196 +
1.197 + return (0);
1.198 + }
1.199 +
1.200 + event_debug(("%s: devpoll_wait reports %d", __func__, res));
1.201 +
1.202 + for (i = 0; i < res; i++) {
1.203 + int which = 0;
1.204 + int what = events[i].revents;
1.205 +
1.206 + if (what & POLLHUP)
1.207 + what |= POLLIN | POLLOUT;
1.208 + else if (what & POLLERR)
1.209 + what |= POLLIN | POLLOUT;
1.210 +
1.211 + if (what & POLLIN)
1.212 + which |= EV_READ;
1.213 + if (what & POLLOUT)
1.214 + which |= EV_WRITE;
1.215 +
1.216 + if (!which)
1.217 + continue;
1.218 +
1.219 + /* XXX(niels): not sure if this works for devpoll */
1.220 + evmap_io_active(base, events[i].fd, which);
1.221 + }
1.222 +
1.223 + return (0);
1.224 +}
1.225 +
1.226 +
1.227 +static int
1.228 +devpoll_add(struct event_base *base, int fd, short old, short events, void *p)
1.229 +{
1.230 + struct devpollop *devpollop = base->evbase;
1.231 + int res;
1.232 + (void)p;
1.233 +
1.234 + /*
1.235 + * It's not necessary to OR the existing read/write events that we
1.236 + * are currently interested in with the new event we are adding.
1.237 + * The /dev/poll driver ORs any new events with the existing events
1.238 + * that it has cached for the fd.
1.239 + */
1.240 +
1.241 + res = 0;
1.242 + if (events & EV_READ)
1.243 + res |= POLLIN;
1.244 + if (events & EV_WRITE)
1.245 + res |= POLLOUT;
1.246 +
1.247 + if (devpoll_queue(devpollop, fd, res) != 0)
1.248 + return (-1);
1.249 +
1.250 + return (0);
1.251 +}
1.252 +
1.253 +static int
1.254 +devpoll_del(struct event_base *base, int fd, short old, short events, void *p)
1.255 +{
1.256 + struct devpollop *devpollop = base->evbase;
1.257 + int res;
1.258 + (void)p;
1.259 +
1.260 + res = 0;
1.261 + if (events & EV_READ)
1.262 + res |= POLLIN;
1.263 + if (events & EV_WRITE)
1.264 + res |= POLLOUT;
1.265 +
1.266 + /*
1.267 + * The only way to remove an fd from the /dev/poll monitored set is
1.268 + * to use POLLREMOVE by itself. This removes ALL events for the fd
1.269 + * provided so if we care about two events and are only removing one
1.270 + * we must re-add the other event after POLLREMOVE.
1.271 + */
1.272 +
1.273 + if (devpoll_queue(devpollop, fd, POLLREMOVE) != 0)
1.274 + return (-1);
1.275 +
1.276 + if ((res & (POLLIN|POLLOUT)) != (POLLIN|POLLOUT)) {
1.277 + /*
1.278 + * We're not deleting all events, so we must resubmit the
1.279 + * event that we are still interested in if one exists.
1.280 + */
1.281 +
1.282 + if ((res & POLLIN) && (old & EV_WRITE)) {
1.283 + /* Deleting read, still care about write */
1.284 + devpoll_queue(devpollop, fd, POLLOUT);
1.285 + } else if ((res & POLLOUT) && (old & EV_READ)) {
1.286 + /* Deleting write, still care about read */
1.287 + devpoll_queue(devpollop, fd, POLLIN);
1.288 + }
1.289 + }
1.290 +
1.291 + return (0);
1.292 +}
1.293 +
1.294 +static void
1.295 +devpoll_dealloc(struct event_base *base)
1.296 +{
1.297 + struct devpollop *devpollop = base->evbase;
1.298 +
1.299 + evsig_dealloc(base);
1.300 + if (devpollop->events)
1.301 + mm_free(devpollop->events);
1.302 + if (devpollop->changes)
1.303 + mm_free(devpollop->changes);
1.304 + if (devpollop->dpfd >= 0)
1.305 + close(devpollop->dpfd);
1.306 +
1.307 + memset(devpollop, 0, sizeof(struct devpollop));
1.308 + mm_free(devpollop);
1.309 +}
