The Tor Browser: ipc/chromium/src/third_party/libevent/evport.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evport.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evport.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
  * Submitted by David Pacheco (dp.spambait@gmail.com)
  *
  * Copyright 2006-2007 Niels Provos
  * Copyright 2007-2012 Niels Provos and Nick Mathewson
  *
  * 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 SUN MICROSYSTEMS, INC. ``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 SUN MICROSYSTEMS, INC. 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.
  */
 /*
  * Copyright (c) 2007 Sun Microsystems. All rights reserved.
  * Use is subject to license terms.
  */
 /*
  * evport.c: event backend using Solaris 10 event ports. See port_create(3C).
  * This implementation is loosely modeled after the one used for select(2) (in
  * select.c).
  *
  * The outstanding events are tracked in a data structure called evport_data.
  * Each entry in the ed_fds array corresponds to a file descriptor, and contains
  * pointers to the read and write events that correspond to that fd. (That is,
  * when the file is readable, the "read" event should handle it, etc.)
  *
  * evport_add and evport_del update this data structure. evport_dispatch uses it
  * to determine where to callback when an event occurs (which it gets from
  * port_getn).
  *
  * Helper functions are used: grow() grows the file descriptor array as
  * necessary when large fd's come in. reassociate() takes care of maintaining
  * the proper file-descriptor/event-port associations.
  *
  * As in the select(2) implementation, signals are handled by evsignal.
  */
 #include "event2/event-config.h"
 #include <sys/time.h>
 #include <sys/queue.h>
 #include <errno.h>
 #include <poll.h>
 #include <port.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
 #include "event2/thread.h"
 #include "evthread-internal.h"
 #include "event-internal.h"
 #include "log-internal.h"
 #include "evsignal-internal.h"
 #include "evmap-internal.h"
 /*
  * Default value for ed_nevents, which is the maximum file descriptor number we
  * can handle. If an event comes in for a file descriptor F > nevents, we will
  * grow the array of file descriptors, doubling its size.
  */
 #define DEFAULT_NFDS	16
 /*
  * EVENTS_PER_GETN is the maximum number of events to retrieve from port_getn on
  * any particular call. You can speed things up by increasing this, but it will
  * (obviously) require more memory.
  */
 #define EVENTS_PER_GETN 8
 /*
  * Per-file-descriptor information about what events we're subscribed to. These
  * fields are NULL if no event is subscribed to either of them.
  */
 struct fd_info {
 	short fdi_what;		/* combinations of EV_READ and EV_WRITE */
 };
 #define FDI_HAS_READ(fdi)  ((fdi)->fdi_what & EV_READ)
 #define FDI_HAS_WRITE(fdi) ((fdi)->fdi_what & EV_WRITE)
 #define FDI_HAS_EVENTS(fdi) (FDI_HAS_READ(fdi) || FDI_HAS_WRITE(fdi))
 #define FDI_TO_SYSEVENTS(fdi) (FDI_HAS_READ(fdi) ? POLLIN : 0) | \
     (FDI_HAS_WRITE(fdi) ? POLLOUT : 0)
 struct evport_data {
 	int		ed_port;	/* event port for system events  */
 	int		ed_nevents;	/* number of allocated fdi's	 */
 	struct fd_info *ed_fds;		/* allocated fdi table		 */
 	/* fdi's that we need to reassoc */
 	int ed_pending[EVENTS_PER_GETN]; /* fd's with pending events */
 };
 static void*	evport_init(struct event_base *);
 static int evport_add(struct event_base *, int fd, short old, short events, void *);
 static int evport_del(struct event_base *, int fd, short old, short events, void *);
 static int	evport_dispatch(struct event_base *, struct timeval *);
 static void	evport_dealloc(struct event_base *);
 const struct eventop evportops = {
 	"evport",
 	evport_init,
 	evport_add,
 	evport_del,
 	evport_dispatch,
 	evport_dealloc,
 , /* need reinit */
 , /* features */
 , /* fdinfo length */
 };
 /*
  * Initialize the event port implementation.
  */
 static void*
 evport_init(struct event_base *base)
 {
 	struct evport_data *evpd;
 	int i;
 	if (!(evpd = mm_calloc(1, sizeof(struct evport_data))))
 		return (NULL);
 	if ((evpd->ed_port = port_create()) == -1) {
 		mm_free(evpd);
 		return (NULL);
 	}
 	/*
 	 * Initialize file descriptor structure
 	 */
 	evpd->ed_fds = mm_calloc(DEFAULT_NFDS, sizeof(struct fd_info));
 	if (evpd->ed_fds == NULL) {
 		close(evpd->ed_port);
 		mm_free(evpd);
 		return (NULL);
 	}
 	evpd->ed_nevents = DEFAULT_NFDS;
 	for (i = 0; i < EVENTS_PER_GETN; i++)
 		evpd->ed_pending[i] = -1;
 	evsig_init(base);
 	return (evpd);
 }
 #ifdef CHECK_INVARIANTS
 /*
  * Checks some basic properties about the evport_data structure. Because it
  * checks all file descriptors, this function can be expensive when the maximum
  * file descriptor ever used is rather large.
  */
 static void
 check_evportop(struct evport_data *evpd)
 {
 	EVUTIL_ASSERT(evpd);
 	EVUTIL_ASSERT(evpd->ed_nevents > 0);
 	EVUTIL_ASSERT(evpd->ed_port > 0);
 	EVUTIL_ASSERT(evpd->ed_fds > 0);
 }
 /*
  * Verifies very basic integrity of a given port_event.
  */
 static void
 check_event(port_event_t* pevt)
 {
 	/*
 	 * We've only registered for PORT_SOURCE_FD events. The only
 	 * other thing we can legitimately receive is PORT_SOURCE_ALERT,
 	 * but since we're not using port_alert either, we can assume
 	 * PORT_SOURCE_FD.
 	 */
 	EVUTIL_ASSERT(pevt->portev_source == PORT_SOURCE_FD);
 	EVUTIL_ASSERT(pevt->portev_user == NULL);
 }
 #else
 #define check_evportop(epop)
 #define check_event(pevt)
 #endif /* CHECK_INVARIANTS */
 /*
  * Doubles the size of the allocated file descriptor array.
  */
 static int
 grow(struct evport_data *epdp, int factor)
 {
 	struct fd_info *tmp;
 	int oldsize = epdp->ed_nevents;
 	int newsize = factor * oldsize;
 	EVUTIL_ASSERT(factor > 1);
 	check_evportop(epdp);
 	tmp = mm_realloc(epdp->ed_fds, sizeof(struct fd_info) * newsize);
 	if (NULL == tmp)
 		return -1;
 	epdp->ed_fds = tmp;
 	memset((char*) (epdp->ed_fds + oldsize), 0,
 	    (newsize - oldsize)*sizeof(struct fd_info));
 	epdp->ed_nevents = newsize;
 	check_evportop(epdp);
 	return 0;
 }
 /*
  * (Re)associates the given file descriptor with the event port. The OS events
  * are specified (implicitly) from the fd_info struct.
  */
 static int
 reassociate(struct evport_data *epdp, struct fd_info *fdip, int fd)
 {
 	int sysevents = FDI_TO_SYSEVENTS(fdip);
 	if (sysevents != 0) {
 		if (port_associate(epdp->ed_port, PORT_SOURCE_FD,
 				   fd, sysevents, NULL) == -1) {
 			event_warn("port_associate");
 			return (-1);
 		}
 	}
 	check_evportop(epdp);
 	return (0);
 }
 /*
  * Main event loop - polls port_getn for some number of events, and processes
  * them.
  */
 static int
 evport_dispatch(struct event_base *base, struct timeval *tv)
 {
 	int i, res;
 	struct evport_data *epdp = base->evbase;
 	port_event_t pevtlist[EVENTS_PER_GETN];
 	/*
 	 * port_getn will block until it has at least nevents events. It will
 	 * also return how many it's given us (which may be more than we asked
 	 * for, as long as it's less than our maximum (EVENTS_PER_GETN)) in
 	 * nevents.
 	 */
 	int nevents = 1;
 	/*
 	 * We have to convert a struct timeval to a struct timespec
 	 * (only difference is nanoseconds vs. microseconds). If no time-based
 	 * events are active, we should wait for I/O (and tv == NULL).
 	 */
 	struct timespec ts;
 	struct timespec *ts_p = NULL;
 	if (tv != NULL) {
 		ts.tv_sec = tv->tv_sec;
 		ts.tv_nsec = tv->tv_usec * 1000;
 		ts_p = &ts;
 	}
 	/*
 	 * Before doing anything else, we need to reassociate the events we hit
 	 * last time which need reassociation. See comment at the end of the
 	 * loop below.
 	 */
 	for (i = 0; i < EVENTS_PER_GETN; ++i) {
 		struct fd_info *fdi = NULL;
 		if (epdp->ed_pending[i] != -1) {
 			fdi = &(epdp->ed_fds[epdp->ed_pending[i]]);
 		}
 		if (fdi != NULL && FDI_HAS_EVENTS(fdi)) {
 			int fd = epdp->ed_pending[i];
 			reassociate(epdp, fdi, fd);
 			epdp->ed_pending[i] = -1;
 		}
 	}
 	EVBASE_RELEASE_LOCK(base, th_base_lock);
 	res = port_getn(epdp->ed_port, pevtlist, EVENTS_PER_GETN,
 	    (unsigned int *) &nevents, ts_p);
 	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
 	if (res == -1) {
 		if (errno == EINTR || errno == EAGAIN) {
 			return (0);
 		} else if (errno == ETIME) {
 			if (nevents == 0)
 				return (0);
 		} else {
 			event_warn("port_getn");
 			return (-1);
 		}
 	}
 	event_debug(("%s: port_getn reports %d events", __func__, nevents));
 	for (i = 0; i < nevents; ++i) {
 		struct fd_info *fdi;
 		port_event_t *pevt = &pevtlist[i];
 		int fd = (int) pevt->portev_object;
 		check_evportop(epdp);
 		check_event(pevt);
 		epdp->ed_pending[i] = fd;
 		/*
 		 * Figure out what kind of event it was
 		 * (because we have to pass this to the callback)
 		 */
 		res = 0;
 		if (pevt->portev_events & (POLLERR|POLLHUP)) {
 			res = EV_READ | EV_WRITE;
 		} else {
 			if (pevt->portev_events & POLLIN)
 				res |= EV_READ;
 			if (pevt->portev_events & POLLOUT)
 				res |= EV_WRITE;
 		}
 		/*
 		 * Check for the error situations or a hangup situation
 		 */
 		if (pevt->portev_events & (POLLERR|POLLHUP|POLLNVAL))
 			res |= EV_READ|EV_WRITE;
 		EVUTIL_ASSERT(epdp->ed_nevents > fd);
 		fdi = &(epdp->ed_fds[fd]);
 		evmap_io_active(base, fd, res);
 	} /* end of all events gotten */
 	check_evportop(epdp);
 	return (0);
 }
 /*
  * Adds the given event (so that you will be notified when it happens via
  * the callback function).
  */
 static int
 evport_add(struct event_base *base, int fd, short old, short events, void *p)
 {
 	struct evport_data *evpd = base->evbase;
 	struct fd_info *fdi;
 	int factor;
 	(void)p;
 	check_evportop(evpd);
 	/*
 	 * If necessary, grow the file descriptor info table
 	 */
 	factor = 1;
 	while (fd >= factor * evpd->ed_nevents)
 		factor *= 2;
 	if (factor > 1) {
 		if (-1 == grow(evpd, factor)) {
 			return (-1);
 		}
 	}
 	fdi = &evpd->ed_fds[fd];
 	fdi->fdi_what |= events;
 	return reassociate(evpd, fdi, fd);
 }
 /*
  * Removes the given event from the list of events to wait for.
  */
 static int
 evport_del(struct event_base *base, int fd, short old, short events, void *p)
 {
 	struct evport_data *evpd = base->evbase;
 	struct fd_info *fdi;
 	int i;
 	int associated = 1;
 	(void)p;
 	check_evportop(evpd);
 	if (evpd->ed_nevents < fd) {
 		return (-1);
 	}
 	for (i = 0; i < EVENTS_PER_GETN; ++i) {
 		if (evpd->ed_pending[i] == fd) {
 			associated = 0;
 			break;
 		}
 	}
 	fdi = &evpd->ed_fds[fd];
 	if (events & EV_READ)
 		fdi->fdi_what &= ~EV_READ;
 	if (events & EV_WRITE)
 		fdi->fdi_what &= ~EV_WRITE;
 	if (associated) {
 		if (!FDI_HAS_EVENTS(fdi) &&
 		    port_dissociate(evpd->ed_port, PORT_SOURCE_FD, fd) == -1) {
 			/*
 			 * Ignore EBADFD error the fd could have been closed
 			 * before event_del() was called.
 			 */
 			if (errno != EBADFD) {
 				event_warn("port_dissociate");
 				return (-1);
 			}
 		} else {
 			if (FDI_HAS_EVENTS(fdi)) {
 				return (reassociate(evpd, fdi, fd));
 			}
 		}
 	} else {
 		if ((fdi->fdi_what & (EV_READ|EV_WRITE)) == 0) {
 			evpd->ed_pending[i] = -1;
 		}
 	}
 	return 0;
 }
 static void
 evport_dealloc(struct event_base *base)
 {
 	struct evport_data *evpd = base->evbase;
 	evsig_dealloc(base);
 	close(evpd->ed_port);
 	if (evpd->ed_fds)
 		mm_free(evpd->ed_fds);
 	mm_free(evpd);
 }

The Tor Browser / annotate

ipc/chromium/src/third_party/libevent/evport.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evport.c