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Diffstat (limited to 'base/pollevent.cc')
| -rw-r--r-- | base/pollevent.cc | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/base/pollevent.cc b/base/pollevent.cc new file mode 100644 index 000000000..fd08d4c4c --- /dev/null +++ b/base/pollevent.cc @@ -0,0 +1,254 @@ +/* + * Copyright (c) 2003 The Regents of The University of Michigan + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * 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; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "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 COPYRIGHT + * OWNER OR CONTRIBUTORS 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 <sys/ioctl.h> +#include <sys/types.h> + +#include <fcntl.h> +#include <signal.h> +#include <unistd.h> + +#include "async.hh" +#include "host.hh" +#include "misc.hh" +#include "pollevent.hh" +#include "universe.hh" + +PollQueue pollQueue; + +///////////////////////////////////////////////////// +// +PollEvent::PollEvent(int _fd, int _events) + : queue(NULL), enabled(true) +{ + pfd.fd = _fd; + pfd.events = _events; +} + +PollEvent::~PollEvent() +{ + if (queue) + queue->remove(this); +} + +void +PollEvent::disable() +{ + if (!enabled) return; + enabled = false; + + if (queue) + queue->copy(); +} + +void +PollEvent::enable() +{ + if (enabled) return; + enabled = true; + + if (queue) + queue->copy(); +} + +///////////////////////////////////////////////////// +// +PollQueue::PollQueue() + : poll_fds(NULL), max_size(0), num_fds(0) +{ } + +PollQueue::~PollQueue() +{ + removeHandler(); + for (int i = 0; i < num_fds; i++) + setupAsyncIO(poll_fds[0].fd, false); + + delete [] poll_fds; +} + +void +PollQueue::copy() +{ + eventvec_t::iterator i = events.begin(); + eventvec_t::iterator end = events.end(); + + num_fds = 0; + + while (i < end) { + if ((*i)->enabled) + poll_fds[num_fds++] = (*i)->pfd; + ++i; + } +} + +void +PollQueue::remove(PollEvent *event) +{ + eventvec_t::iterator i = events.begin(); + eventvec_t::iterator end = events.end(); + + while (i < end) { + if (*i == event) { + events.erase(i); + copy(); + event->queue = NULL; + return; + } + + ++i; + } + + panic("Event does not exist. Cannot remove."); +} + +void +PollQueue::schedule(PollEvent *event) +{ + if (event->queue) + panic("Event already scheduled!"); + + event->queue = this; + events.push_back(event); + setupAsyncIO(event->pfd.fd, true); + + // if we ran out of space in the fd array, double the capacity + // if this is the first time that we've scheduled an event, create + // the array with an initial size of 16 + if (++num_fds > max_size) { + if (max_size > 0) { + delete [] poll_fds; + max_size *= 2; + } else { + max_size = 16; + setupHandler(); + } + + poll_fds = new pollfd[max_size]; + } + + copy(); +} + +void +PollQueue::service() +{ + int ret = poll(poll_fds, num_fds, 0); + + if (ret <= 0) + return; + + for (int i = 0; i < num_fds; i++) { + int revents = poll_fds[i].revents; + if (revents) { + events[i]->process(revents); + if (--ret <= 0) + break; + } + } +} + +struct sigaction PollQueue::oldio; +struct sigaction PollQueue::oldalrm; +bool PollQueue::handler = false; + +void +PollQueue::setupAsyncIO(int fd, bool set) +{ + int flags = fcntl(fd, F_GETFL); + if (flags == -1) + panic("Could not set up async IO"); + + if (set) + flags |= FASYNC; + else + flags &= ~(FASYNC); + + if (fcntl(fd, F_SETFL, flags) == -1) + panic("Could not set up async IO"); + + if (set) { + if (fcntl(fd, F_SETOWN, getpid()) == -1) + panic("Could not set up async IO"); + } +} + +void +PollQueue::setupHandler() +{ + struct sigaction act; + + act.sa_handler = handleIO; + sigemptyset(&act.sa_mask); + act.sa_flags = 0; + + if (sigaction(SIGIO, &act, &oldio) == -1) + panic("could not do sigaction"); + + act.sa_handler = handleALRM; + sigemptyset(&act.sa_mask); + act.sa_flags = 0; + + if (sigaction(SIGALRM, &act, &oldalrm) == -1) + panic("could not do sigaction"); + + alarm(1); + + handler = true; +} + +void +PollQueue::removeHandler() +{ + if (sigaction(SIGIO, &oldio, NULL) == -1) + panic("could not remove handler"); + + if (sigaction(SIGIO, &oldalrm, NULL) == -1) + panic("could not remove handler"); +} + +void +PollQueue::handleIO(int sig) +{ + if (sig != SIGIO) + panic("Wrong Handler"); + + async_event = true; + async_io = true; +} + +void +PollQueue::handleALRM(int sig) +{ + if (sig != SIGALRM) + panic("Wrong Handler"); + + async_event = true; + async_alarm = true; + alarm(1); +} + |