The Tor Browser: ipc/chromium/src/third_party/libevent/buffer

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

ipc/chromium/src/third_party/libevent/buffer_iocp.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.

 /*
  * Copyright (c) 2009-2012 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 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.
  */
 /**
    @file buffer_iocp.c
    This module implements overlapped read and write functions for evbuffer
    objects on Windows.
 */
 #include "event2/buffer.h"
 #include "event2/buffer_compat.h"
 #include "event2/util.h"
 #include "event2/thread.h"
 #include "event2/event-config.h"
 #include "util-internal.h"
 #include "evthread-internal.h"
 #include "evbuffer-internal.h"
 #include "iocp-internal.h"
 #include "mm-internal.h"
 #include <winsock2.h>
 #include <windows.h>
 #include <stdio.h>
 #define MAX_WSABUFS 16
 /** An evbuffer that can handle overlapped IO. */
 struct evbuffer_overlapped {
 	struct evbuffer buffer;
 	/** The socket that we're doing overlapped IO on. */
 	evutil_socket_t fd;
 	/** pending I/O type */
 	unsigned read_in_progress : 1;
 	unsigned write_in_progress : 1;
 	/** The first pinned chain in the buffer. */
 	struct evbuffer_chain *first_pinned;
 	/** How many chains are pinned; how many of the fields in buffers
 	 * are we using. */
 	int n_buffers;
 	WSABUF buffers[MAX_WSABUFS];
 };
 /** Given an evbuffer, return the correponding evbuffer structure, or NULL if
  * the evbuffer isn't overlapped. */
 static inline struct evbuffer_overlapped *
 upcast_evbuffer(struct evbuffer *buf)
 {
 	if (!buf || !buf->is_overlapped)
 		return NULL;
 	return EVUTIL_UPCAST(buf, struct evbuffer_overlapped, buffer);
 }
 /** Unpin all the chains noted as pinned in 'eo'. */
 static void
 pin_release(struct evbuffer_overlapped *eo, unsigned flag)
 {
 	int i;
 	struct evbuffer_chain *next, *chain = eo->first_pinned;
 	for (i = 0; i < eo->n_buffers; ++i) {
 		EVUTIL_ASSERT(chain);
 		next = chain->next;
 		_evbuffer_chain_unpin(chain, flag);
 		chain = next;
 	}
 }
 void
 evbuffer_commit_read(struct evbuffer *evbuf, ev_ssize_t nBytes)
 {
 	struct evbuffer_overlapped *buf = upcast_evbuffer(evbuf);
 	struct evbuffer_chain **chainp;
 	size_t remaining, len;
 	unsigned i;
 	EVBUFFER_LOCK(evbuf);
 	EVUTIL_ASSERT(buf->read_in_progress && !buf->write_in_progress);
 	EVUTIL_ASSERT(nBytes >= 0); /* XXXX Can this be false? */
 	evbuffer_unfreeze(evbuf, 0);
 	chainp = evbuf->last_with_datap;
 	if (!((*chainp)->flags & EVBUFFER_MEM_PINNED_R))
 		chainp = &(*chainp)->next;
 	remaining = nBytes;
 	for (i = 0; remaining > 0 && i < (unsigned)buf->n_buffers; ++i) {
 		EVUTIL_ASSERT(*chainp);
 		len = buf->buffers[i].len;
 		if (remaining < len)
 			len = remaining;
 		(*chainp)->off += len;
 		evbuf->last_with_datap = chainp;
 		remaining -= len;
 		chainp = &(*chainp)->next;
 	}
 	pin_release(buf, EVBUFFER_MEM_PINNED_R);
 	buf->read_in_progress = 0;
 	evbuf->total_len += nBytes;
 	evbuf->n_add_for_cb += nBytes;
 	evbuffer_invoke_callbacks(evbuf);
 	_evbuffer_decref_and_unlock(evbuf);
 }
 void
 evbuffer_commit_write(struct evbuffer *evbuf, ev_ssize_t nBytes)
 {
 	struct evbuffer_overlapped *buf = upcast_evbuffer(evbuf);
 	EVBUFFER_LOCK(evbuf);
 	EVUTIL_ASSERT(buf->write_in_progress && !buf->read_in_progress);
 	evbuffer_unfreeze(evbuf, 1);
 	evbuffer_drain(evbuf, nBytes);
 	pin_release(buf,EVBUFFER_MEM_PINNED_W);
 	buf->write_in_progress = 0;
 	_evbuffer_decref_and_unlock(evbuf);
 }
 struct evbuffer *
 evbuffer_overlapped_new(evutil_socket_t fd)
 {
 	struct evbuffer_overlapped *evo;
 	evo = mm_calloc(1, sizeof(struct evbuffer_overlapped));
 	if (!evo)
 		return NULL;
 	TAILQ_INIT(&evo->buffer.callbacks);
 	evo->buffer.refcnt = 1;
 	evo->buffer.last_with_datap = &evo->buffer.first;
 	evo->buffer.is_overlapped = 1;
 	evo->fd = fd;
 	return &evo->buffer;
 }
 int
 evbuffer_launch_write(struct evbuffer *buf, ev_ssize_t at_most,
 		struct event_overlapped *ol)
 {
 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
 	int r = -1;
 	int i;
 	struct evbuffer_chain *chain;
 	DWORD bytesSent;
 	if (!buf) {
 		/* No buffer, or it isn't overlapped */
 		return -1;
 	}
 	EVBUFFER_LOCK(buf);
 	EVUTIL_ASSERT(!buf_o->read_in_progress);
 	if (buf->freeze_start || buf_o->write_in_progress)
 		goto done;
 	if (!buf->total_len) {
 		/* Nothing to write */
 		r = 0;
 		goto done;
 	} else if (at_most < 0 || (size_t)at_most > buf->total_len) {
 		at_most = buf->total_len;
 	}
 	evbuffer_freeze(buf, 1);
 	buf_o->first_pinned = NULL;
 	buf_o->n_buffers = 0;
 	memset(buf_o->buffers, 0, sizeof(buf_o->buffers));
 	chain = buf_o->first_pinned = buf->first;
 	for (i=0; i < MAX_WSABUFS && chain; ++i, chain=chain->next) {
 		WSABUF *b = &buf_o->buffers[i];
 		b->buf = (char*)( chain->buffer + chain->misalign );
 		_evbuffer_chain_pin(chain, EVBUFFER_MEM_PINNED_W);
 		if ((size_t)at_most > chain->off) {
 			/* XXXX Cast is safe for now, since win32 has no
 			   mmaped chains.  But later, we need to have this
 			   add more WSAbufs if chain->off is greater than
 			   ULONG_MAX */
 			b->len = (unsigned long)chain->off;
 			at_most -= chain->off;
 		} else {
 			b->len = (unsigned long)at_most;
 			++i;
 			break;
 		}
 	}
 	buf_o->n_buffers = i;
 	_evbuffer_incref(buf);
 	if (WSASend(buf_o->fd, buf_o->buffers, i, &bytesSent, 0,
 		&ol->overlapped, NULL)) {
 		int error = WSAGetLastError();
 		if (error != WSA_IO_PENDING) {
 			/* An actual error. */
 			pin_release(buf_o, EVBUFFER_MEM_PINNED_W);
 			evbuffer_unfreeze(buf, 1);
 			evbuffer_free(buf); /* decref */
 			goto done;
 		}
 	}
 	buf_o->write_in_progress = 1;
 	r = 0;
 done:
 	EVBUFFER_UNLOCK(buf);
 	return r;
 }
 int
 evbuffer_launch_read(struct evbuffer *buf, size_t at_most,
 		struct event_overlapped *ol)
 {
 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
 	int r = -1, i;
 	int nvecs;
 	int npin=0;
 	struct evbuffer_chain *chain=NULL, **chainp;
 	DWORD bytesRead;
 	DWORD flags = 0;
 	struct evbuffer_iovec vecs[MAX_WSABUFS];
 	if (!buf_o)
 		return -1;
 	EVBUFFER_LOCK(buf);
 	EVUTIL_ASSERT(!buf_o->write_in_progress);
 	if (buf->freeze_end || buf_o->read_in_progress)
 		goto done;
 	buf_o->first_pinned = NULL;
 	buf_o->n_buffers = 0;
 	memset(buf_o->buffers, 0, sizeof(buf_o->buffers));
 	if (_evbuffer_expand_fast(buf, at_most, MAX_WSABUFS) == -1)
 		goto done;
 	evbuffer_freeze(buf, 0);
 	nvecs = _evbuffer_read_setup_vecs(buf, at_most,
 	    vecs, MAX_WSABUFS, &chainp, 1);
 	for (i=0;i<nvecs;++i) {
 		WSABUF_FROM_EVBUFFER_IOV(
 			&buf_o->buffers[i],
 			&vecs[i]);
 	}
 	buf_o->n_buffers = nvecs;
 	buf_o->first_pinned = chain = *chainp;
 	npin=0;
 	for ( ; chain; chain = chain->next) {
 		_evbuffer_chain_pin(chain, EVBUFFER_MEM_PINNED_R);
 		++npin;
 	}
 	EVUTIL_ASSERT(npin == nvecs);
 	_evbuffer_incref(buf);
 	if (WSARecv(buf_o->fd, buf_o->buffers, nvecs, &bytesRead, &flags,
 		    &ol->overlapped, NULL)) {
 		int error = WSAGetLastError();
 		if (error != WSA_IO_PENDING) {
 			/* An actual error. */
 			pin_release(buf_o, EVBUFFER_MEM_PINNED_R);
 			evbuffer_unfreeze(buf, 0);
 			evbuffer_free(buf); /* decref */
 			goto done;
 		}
 	}
 	buf_o->read_in_progress = 1;
 	r = 0;
 done:
 	EVBUFFER_UNLOCK(buf);
 	return r;
 }
 evutil_socket_t
 _evbuffer_overlapped_get_fd(struct evbuffer *buf)
 {
 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
 	return buf_o ? buf_o->fd : -1;
 }
 void
 _evbuffer_overlapped_set_fd(struct evbuffer *buf, evutil_socket_t fd)
 {
 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
 	EVBUFFER_LOCK(buf);
 	/* XXX is this right?, should it cancel current I/O operations? */
 	if (buf_o)
 		buf_o->fd = fd;
 	EVBUFFER_UNLOCK(buf);
 }

The Tor Browser / annotate

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

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