xref: /aosp_15_r20/external/libevent/buffer_iocp.c (revision 663afb9b963571284e0f0a60f257164ab54f64bf)
1*663afb9bSAndroid Build Coastguard Worker /*
2*663afb9bSAndroid Build Coastguard Worker  * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson
3*663afb9bSAndroid Build Coastguard Worker  *
4*663afb9bSAndroid Build Coastguard Worker  * Redistribution and use in source and binary forms, with or without
5*663afb9bSAndroid Build Coastguard Worker  * modification, are permitted provided that the following conditions
6*663afb9bSAndroid Build Coastguard Worker  * are met:
7*663afb9bSAndroid Build Coastguard Worker  * 1. Redistributions of source code must retain the above copyright
8*663afb9bSAndroid Build Coastguard Worker  *    notice, this list of conditions and the following disclaimer.
9*663afb9bSAndroid Build Coastguard Worker  * 2. Redistributions in binary form must reproduce the above copyright
10*663afb9bSAndroid Build Coastguard Worker  *    notice, this list of conditions and the following disclaimer in the
11*663afb9bSAndroid Build Coastguard Worker  *    documentation and/or other materials provided with the distribution.
12*663afb9bSAndroid Build Coastguard Worker  * 3. The name of the author may not be used to endorse or promote products
13*663afb9bSAndroid Build Coastguard Worker  *    derived from this software without specific prior written permission.
14*663afb9bSAndroid Build Coastguard Worker  *
15*663afb9bSAndroid Build Coastguard Worker  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16*663afb9bSAndroid Build Coastguard Worker  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17*663afb9bSAndroid Build Coastguard Worker  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18*663afb9bSAndroid Build Coastguard Worker  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19*663afb9bSAndroid Build Coastguard Worker  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20*663afb9bSAndroid Build Coastguard Worker  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21*663afb9bSAndroid Build Coastguard Worker  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22*663afb9bSAndroid Build Coastguard Worker  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23*663afb9bSAndroid Build Coastguard Worker  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24*663afb9bSAndroid Build Coastguard Worker  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25*663afb9bSAndroid Build Coastguard Worker  */
26*663afb9bSAndroid Build Coastguard Worker 
27*663afb9bSAndroid Build Coastguard Worker /**
28*663afb9bSAndroid Build Coastguard Worker    @file buffer_iocp.c
29*663afb9bSAndroid Build Coastguard Worker 
30*663afb9bSAndroid Build Coastguard Worker    This module implements overlapped read and write functions for evbuffer
31*663afb9bSAndroid Build Coastguard Worker    objects on Windows.
32*663afb9bSAndroid Build Coastguard Worker */
33*663afb9bSAndroid Build Coastguard Worker #include "event2/event-config.h"
34*663afb9bSAndroid Build Coastguard Worker #include "evconfig-private.h"
35*663afb9bSAndroid Build Coastguard Worker 
36*663afb9bSAndroid Build Coastguard Worker #include "event2/buffer.h"
37*663afb9bSAndroid Build Coastguard Worker #include "event2/buffer_compat.h"
38*663afb9bSAndroid Build Coastguard Worker #include "event2/util.h"
39*663afb9bSAndroid Build Coastguard Worker #include "event2/thread.h"
40*663afb9bSAndroid Build Coastguard Worker #include "util-internal.h"
41*663afb9bSAndroid Build Coastguard Worker #include "evthread-internal.h"
42*663afb9bSAndroid Build Coastguard Worker #include "evbuffer-internal.h"
43*663afb9bSAndroid Build Coastguard Worker #include "iocp-internal.h"
44*663afb9bSAndroid Build Coastguard Worker #include "mm-internal.h"
45*663afb9bSAndroid Build Coastguard Worker 
46*663afb9bSAndroid Build Coastguard Worker #include <winsock2.h>
47*663afb9bSAndroid Build Coastguard Worker #include <winerror.h>
48*663afb9bSAndroid Build Coastguard Worker #include <windows.h>
49*663afb9bSAndroid Build Coastguard Worker #include <stdio.h>
50*663afb9bSAndroid Build Coastguard Worker 
51*663afb9bSAndroid Build Coastguard Worker #define MAX_WSABUFS 16
52*663afb9bSAndroid Build Coastguard Worker 
53*663afb9bSAndroid Build Coastguard Worker /** An evbuffer that can handle overlapped IO. */
54*663afb9bSAndroid Build Coastguard Worker struct evbuffer_overlapped {
55*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer buffer;
56*663afb9bSAndroid Build Coastguard Worker 	/** The socket that we're doing overlapped IO on. */
57*663afb9bSAndroid Build Coastguard Worker 	evutil_socket_t fd;
58*663afb9bSAndroid Build Coastguard Worker 
59*663afb9bSAndroid Build Coastguard Worker 	/** pending I/O type */
60*663afb9bSAndroid Build Coastguard Worker 	unsigned read_in_progress : 1;
61*663afb9bSAndroid Build Coastguard Worker 	unsigned write_in_progress : 1;
62*663afb9bSAndroid Build Coastguard Worker 
63*663afb9bSAndroid Build Coastguard Worker 	/** The first pinned chain in the buffer. */
64*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_chain *first_pinned;
65*663afb9bSAndroid Build Coastguard Worker 
66*663afb9bSAndroid Build Coastguard Worker 	/** How many chains are pinned; how many of the fields in buffers
67*663afb9bSAndroid Build Coastguard Worker 	 * are we using. */
68*663afb9bSAndroid Build Coastguard Worker 	int n_buffers;
69*663afb9bSAndroid Build Coastguard Worker 	WSABUF buffers[MAX_WSABUFS];
70*663afb9bSAndroid Build Coastguard Worker };
71*663afb9bSAndroid Build Coastguard Worker 
72*663afb9bSAndroid Build Coastguard Worker /** Given an evbuffer, return the correponding evbuffer structure, or NULL if
73*663afb9bSAndroid Build Coastguard Worker  * the evbuffer isn't overlapped. */
74*663afb9bSAndroid Build Coastguard Worker static inline struct evbuffer_overlapped *
upcast_evbuffer(struct evbuffer * buf)75*663afb9bSAndroid Build Coastguard Worker upcast_evbuffer(struct evbuffer *buf)
76*663afb9bSAndroid Build Coastguard Worker {
77*663afb9bSAndroid Build Coastguard Worker 	if (!buf || !buf->is_overlapped)
78*663afb9bSAndroid Build Coastguard Worker 		return NULL;
79*663afb9bSAndroid Build Coastguard Worker 	return EVUTIL_UPCAST(buf, struct evbuffer_overlapped, buffer);
80*663afb9bSAndroid Build Coastguard Worker }
81*663afb9bSAndroid Build Coastguard Worker 
82*663afb9bSAndroid Build Coastguard Worker /** Unpin all the chains noted as pinned in 'eo'. */
83*663afb9bSAndroid Build Coastguard Worker static void
pin_release(struct evbuffer_overlapped * eo,unsigned flag)84*663afb9bSAndroid Build Coastguard Worker pin_release(struct evbuffer_overlapped *eo, unsigned flag)
85*663afb9bSAndroid Build Coastguard Worker {
86*663afb9bSAndroid Build Coastguard Worker 	int i;
87*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_chain *next, *chain = eo->first_pinned;
88*663afb9bSAndroid Build Coastguard Worker 
89*663afb9bSAndroid Build Coastguard Worker 	for (i = 0; i < eo->n_buffers; ++i) {
90*663afb9bSAndroid Build Coastguard Worker 		EVUTIL_ASSERT(chain);
91*663afb9bSAndroid Build Coastguard Worker 		next = chain->next;
92*663afb9bSAndroid Build Coastguard Worker 		evbuffer_chain_unpin_(chain, flag);
93*663afb9bSAndroid Build Coastguard Worker 		chain = next;
94*663afb9bSAndroid Build Coastguard Worker 	}
95*663afb9bSAndroid Build Coastguard Worker }
96*663afb9bSAndroid Build Coastguard Worker 
97*663afb9bSAndroid Build Coastguard Worker void
evbuffer_commit_read_(struct evbuffer * evbuf,ev_ssize_t nBytes)98*663afb9bSAndroid Build Coastguard Worker evbuffer_commit_read_(struct evbuffer *evbuf, ev_ssize_t nBytes)
99*663afb9bSAndroid Build Coastguard Worker {
100*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_overlapped *buf = upcast_evbuffer(evbuf);
101*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_chain **chainp;
102*663afb9bSAndroid Build Coastguard Worker 	size_t remaining, len;
103*663afb9bSAndroid Build Coastguard Worker 	unsigned i;
104*663afb9bSAndroid Build Coastguard Worker 
105*663afb9bSAndroid Build Coastguard Worker 	EVBUFFER_LOCK(evbuf);
106*663afb9bSAndroid Build Coastguard Worker 	EVUTIL_ASSERT(buf->read_in_progress && !buf->write_in_progress);
107*663afb9bSAndroid Build Coastguard Worker 	EVUTIL_ASSERT(nBytes >= 0); /* XXXX Can this be false? */
108*663afb9bSAndroid Build Coastguard Worker 
109*663afb9bSAndroid Build Coastguard Worker 	evbuffer_unfreeze(evbuf, 0);
110*663afb9bSAndroid Build Coastguard Worker 
111*663afb9bSAndroid Build Coastguard Worker 	chainp = evbuf->last_with_datap;
112*663afb9bSAndroid Build Coastguard Worker 	if (!((*chainp)->flags & EVBUFFER_MEM_PINNED_R))
113*663afb9bSAndroid Build Coastguard Worker 		chainp = &(*chainp)->next;
114*663afb9bSAndroid Build Coastguard Worker 	remaining = nBytes;
115*663afb9bSAndroid Build Coastguard Worker 	for (i = 0; remaining > 0 && i < (unsigned)buf->n_buffers; ++i) {
116*663afb9bSAndroid Build Coastguard Worker 		EVUTIL_ASSERT(*chainp);
117*663afb9bSAndroid Build Coastguard Worker 		len = buf->buffers[i].len;
118*663afb9bSAndroid Build Coastguard Worker 		if (remaining < len)
119*663afb9bSAndroid Build Coastguard Worker 			len = remaining;
120*663afb9bSAndroid Build Coastguard Worker 		(*chainp)->off += len;
121*663afb9bSAndroid Build Coastguard Worker 		evbuf->last_with_datap = chainp;
122*663afb9bSAndroid Build Coastguard Worker 		remaining -= len;
123*663afb9bSAndroid Build Coastguard Worker 		chainp = &(*chainp)->next;
124*663afb9bSAndroid Build Coastguard Worker 	}
125*663afb9bSAndroid Build Coastguard Worker 
126*663afb9bSAndroid Build Coastguard Worker 	pin_release(buf, EVBUFFER_MEM_PINNED_R);
127*663afb9bSAndroid Build Coastguard Worker 
128*663afb9bSAndroid Build Coastguard Worker 	buf->read_in_progress = 0;
129*663afb9bSAndroid Build Coastguard Worker 
130*663afb9bSAndroid Build Coastguard Worker 	evbuf->total_len += nBytes;
131*663afb9bSAndroid Build Coastguard Worker 	evbuf->n_add_for_cb += nBytes;
132*663afb9bSAndroid Build Coastguard Worker 
133*663afb9bSAndroid Build Coastguard Worker 	evbuffer_invoke_callbacks_(evbuf);
134*663afb9bSAndroid Build Coastguard Worker 
135*663afb9bSAndroid Build Coastguard Worker 	evbuffer_decref_and_unlock_(evbuf);
136*663afb9bSAndroid Build Coastguard Worker }
137*663afb9bSAndroid Build Coastguard Worker 
138*663afb9bSAndroid Build Coastguard Worker void
evbuffer_commit_write_(struct evbuffer * evbuf,ev_ssize_t nBytes)139*663afb9bSAndroid Build Coastguard Worker evbuffer_commit_write_(struct evbuffer *evbuf, ev_ssize_t nBytes)
140*663afb9bSAndroid Build Coastguard Worker {
141*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_overlapped *buf = upcast_evbuffer(evbuf);
142*663afb9bSAndroid Build Coastguard Worker 
143*663afb9bSAndroid Build Coastguard Worker 	EVBUFFER_LOCK(evbuf);
144*663afb9bSAndroid Build Coastguard Worker 	EVUTIL_ASSERT(buf->write_in_progress && !buf->read_in_progress);
145*663afb9bSAndroid Build Coastguard Worker 	evbuffer_unfreeze(evbuf, 1);
146*663afb9bSAndroid Build Coastguard Worker 	evbuffer_drain(evbuf, nBytes);
147*663afb9bSAndroid Build Coastguard Worker 	pin_release(buf,EVBUFFER_MEM_PINNED_W);
148*663afb9bSAndroid Build Coastguard Worker 	buf->write_in_progress = 0;
149*663afb9bSAndroid Build Coastguard Worker 	evbuffer_decref_and_unlock_(evbuf);
150*663afb9bSAndroid Build Coastguard Worker }
151*663afb9bSAndroid Build Coastguard Worker 
152*663afb9bSAndroid Build Coastguard Worker struct evbuffer *
evbuffer_overlapped_new_(evutil_socket_t fd)153*663afb9bSAndroid Build Coastguard Worker evbuffer_overlapped_new_(evutil_socket_t fd)
154*663afb9bSAndroid Build Coastguard Worker {
155*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_overlapped *evo;
156*663afb9bSAndroid Build Coastguard Worker 
157*663afb9bSAndroid Build Coastguard Worker 	evo = mm_calloc(1, sizeof(struct evbuffer_overlapped));
158*663afb9bSAndroid Build Coastguard Worker 	if (!evo)
159*663afb9bSAndroid Build Coastguard Worker 		return NULL;
160*663afb9bSAndroid Build Coastguard Worker 
161*663afb9bSAndroid Build Coastguard Worker 	LIST_INIT(&evo->buffer.callbacks);
162*663afb9bSAndroid Build Coastguard Worker 	evo->buffer.refcnt = 1;
163*663afb9bSAndroid Build Coastguard Worker 	evo->buffer.last_with_datap = &evo->buffer.first;
164*663afb9bSAndroid Build Coastguard Worker 
165*663afb9bSAndroid Build Coastguard Worker 	evo->buffer.is_overlapped = 1;
166*663afb9bSAndroid Build Coastguard Worker 	evo->fd = fd;
167*663afb9bSAndroid Build Coastguard Worker 
168*663afb9bSAndroid Build Coastguard Worker 	return &evo->buffer;
169*663afb9bSAndroid Build Coastguard Worker }
170*663afb9bSAndroid Build Coastguard Worker 
171*663afb9bSAndroid Build Coastguard Worker int
evbuffer_launch_write_(struct evbuffer * buf,ev_ssize_t at_most,struct event_overlapped * ol)172*663afb9bSAndroid Build Coastguard Worker evbuffer_launch_write_(struct evbuffer *buf, ev_ssize_t at_most,
173*663afb9bSAndroid Build Coastguard Worker 		struct event_overlapped *ol)
174*663afb9bSAndroid Build Coastguard Worker {
175*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
176*663afb9bSAndroid Build Coastguard Worker 	int r = -1;
177*663afb9bSAndroid Build Coastguard Worker 	int i;
178*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_chain *chain;
179*663afb9bSAndroid Build Coastguard Worker 	DWORD bytesSent;
180*663afb9bSAndroid Build Coastguard Worker 
181*663afb9bSAndroid Build Coastguard Worker 	if (!buf) {
182*663afb9bSAndroid Build Coastguard Worker 		/* No buffer, or it isn't overlapped */
183*663afb9bSAndroid Build Coastguard Worker 		return -1;
184*663afb9bSAndroid Build Coastguard Worker 	}
185*663afb9bSAndroid Build Coastguard Worker 
186*663afb9bSAndroid Build Coastguard Worker 	EVBUFFER_LOCK(buf);
187*663afb9bSAndroid Build Coastguard Worker 	EVUTIL_ASSERT(!buf_o->read_in_progress);
188*663afb9bSAndroid Build Coastguard Worker 	if (buf->freeze_start || buf_o->write_in_progress)
189*663afb9bSAndroid Build Coastguard Worker 		goto done;
190*663afb9bSAndroid Build Coastguard Worker 	if (!buf->total_len) {
191*663afb9bSAndroid Build Coastguard Worker 		/* Nothing to write */
192*663afb9bSAndroid Build Coastguard Worker 		r = 0;
193*663afb9bSAndroid Build Coastguard Worker 		goto done;
194*663afb9bSAndroid Build Coastguard Worker 	} else if (at_most < 0 || (size_t)at_most > buf->total_len) {
195*663afb9bSAndroid Build Coastguard Worker 		at_most = buf->total_len;
196*663afb9bSAndroid Build Coastguard Worker 	}
197*663afb9bSAndroid Build Coastguard Worker 	evbuffer_freeze(buf, 1);
198*663afb9bSAndroid Build Coastguard Worker 
199*663afb9bSAndroid Build Coastguard Worker 	buf_o->first_pinned = NULL;
200*663afb9bSAndroid Build Coastguard Worker 	buf_o->n_buffers = 0;
201*663afb9bSAndroid Build Coastguard Worker 	memset(buf_o->buffers, 0, sizeof(buf_o->buffers));
202*663afb9bSAndroid Build Coastguard Worker 
203*663afb9bSAndroid Build Coastguard Worker 	chain = buf_o->first_pinned = buf->first;
204*663afb9bSAndroid Build Coastguard Worker 
205*663afb9bSAndroid Build Coastguard Worker 	for (i=0; i < MAX_WSABUFS && chain; ++i, chain=chain->next) {
206*663afb9bSAndroid Build Coastguard Worker 		WSABUF *b = &buf_o->buffers[i];
207*663afb9bSAndroid Build Coastguard Worker 		b->buf = (char*)( chain->buffer + chain->misalign );
208*663afb9bSAndroid Build Coastguard Worker 		evbuffer_chain_pin_(chain, EVBUFFER_MEM_PINNED_W);
209*663afb9bSAndroid Build Coastguard Worker 
210*663afb9bSAndroid Build Coastguard Worker 		if ((size_t)at_most > chain->off) {
211*663afb9bSAndroid Build Coastguard Worker 			/* XXXX Cast is safe for now, since win32 has no
212*663afb9bSAndroid Build Coastguard Worker 			   mmaped chains.  But later, we need to have this
213*663afb9bSAndroid Build Coastguard Worker 			   add more WSAbufs if chain->off is greater than
214*663afb9bSAndroid Build Coastguard Worker 			   ULONG_MAX */
215*663afb9bSAndroid Build Coastguard Worker 			b->len = (unsigned long)chain->off;
216*663afb9bSAndroid Build Coastguard Worker 			at_most -= chain->off;
217*663afb9bSAndroid Build Coastguard Worker 		} else {
218*663afb9bSAndroid Build Coastguard Worker 			b->len = (unsigned long)at_most;
219*663afb9bSAndroid Build Coastguard Worker 			++i;
220*663afb9bSAndroid Build Coastguard Worker 			break;
221*663afb9bSAndroid Build Coastguard Worker 		}
222*663afb9bSAndroid Build Coastguard Worker 	}
223*663afb9bSAndroid Build Coastguard Worker 
224*663afb9bSAndroid Build Coastguard Worker 	buf_o->n_buffers = i;
225*663afb9bSAndroid Build Coastguard Worker 	evbuffer_incref_(buf);
226*663afb9bSAndroid Build Coastguard Worker 	if (WSASend(buf_o->fd, buf_o->buffers, i, &bytesSent, 0,
227*663afb9bSAndroid Build Coastguard Worker 		&ol->overlapped, NULL)) {
228*663afb9bSAndroid Build Coastguard Worker 		int error = WSAGetLastError();
229*663afb9bSAndroid Build Coastguard Worker 		if (error != WSA_IO_PENDING) {
230*663afb9bSAndroid Build Coastguard Worker 			/* An actual error. */
231*663afb9bSAndroid Build Coastguard Worker 			pin_release(buf_o, EVBUFFER_MEM_PINNED_W);
232*663afb9bSAndroid Build Coastguard Worker 			evbuffer_unfreeze(buf, 1);
233*663afb9bSAndroid Build Coastguard Worker 			evbuffer_free(buf); /* decref */
234*663afb9bSAndroid Build Coastguard Worker 			goto done;
235*663afb9bSAndroid Build Coastguard Worker 		}
236*663afb9bSAndroid Build Coastguard Worker 	}
237*663afb9bSAndroid Build Coastguard Worker 
238*663afb9bSAndroid Build Coastguard Worker 	buf_o->write_in_progress = 1;
239*663afb9bSAndroid Build Coastguard Worker 	r = 0;
240*663afb9bSAndroid Build Coastguard Worker done:
241*663afb9bSAndroid Build Coastguard Worker 	EVBUFFER_UNLOCK(buf);
242*663afb9bSAndroid Build Coastguard Worker 	return r;
243*663afb9bSAndroid Build Coastguard Worker }
244*663afb9bSAndroid Build Coastguard Worker 
245*663afb9bSAndroid Build Coastguard Worker int
evbuffer_launch_read_(struct evbuffer * buf,size_t at_most,struct event_overlapped * ol)246*663afb9bSAndroid Build Coastguard Worker evbuffer_launch_read_(struct evbuffer *buf, size_t at_most,
247*663afb9bSAndroid Build Coastguard Worker 		struct event_overlapped *ol)
248*663afb9bSAndroid Build Coastguard Worker {
249*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
250*663afb9bSAndroid Build Coastguard Worker 	int r = -1, i;
251*663afb9bSAndroid Build Coastguard Worker 	int nvecs;
252*663afb9bSAndroid Build Coastguard Worker 	int npin=0;
253*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_chain *chain=NULL, **chainp;
254*663afb9bSAndroid Build Coastguard Worker 	DWORD bytesRead;
255*663afb9bSAndroid Build Coastguard Worker 	DWORD flags = 0;
256*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_iovec vecs[MAX_WSABUFS];
257*663afb9bSAndroid Build Coastguard Worker 
258*663afb9bSAndroid Build Coastguard Worker 	if (!buf_o)
259*663afb9bSAndroid Build Coastguard Worker 		return -1;
260*663afb9bSAndroid Build Coastguard Worker 	EVBUFFER_LOCK(buf);
261*663afb9bSAndroid Build Coastguard Worker 	EVUTIL_ASSERT(!buf_o->write_in_progress);
262*663afb9bSAndroid Build Coastguard Worker 	if (buf->freeze_end || buf_o->read_in_progress)
263*663afb9bSAndroid Build Coastguard Worker 		goto done;
264*663afb9bSAndroid Build Coastguard Worker 
265*663afb9bSAndroid Build Coastguard Worker 	buf_o->first_pinned = NULL;
266*663afb9bSAndroid Build Coastguard Worker 	buf_o->n_buffers = 0;
267*663afb9bSAndroid Build Coastguard Worker 	memset(buf_o->buffers, 0, sizeof(buf_o->buffers));
268*663afb9bSAndroid Build Coastguard Worker 
269*663afb9bSAndroid Build Coastguard Worker 	if (evbuffer_expand_fast_(buf, at_most, MAX_WSABUFS) == -1)
270*663afb9bSAndroid Build Coastguard Worker 		goto done;
271*663afb9bSAndroid Build Coastguard Worker 	evbuffer_freeze(buf, 0);
272*663afb9bSAndroid Build Coastguard Worker 
273*663afb9bSAndroid Build Coastguard Worker 	nvecs = evbuffer_read_setup_vecs_(buf, at_most,
274*663afb9bSAndroid Build Coastguard Worker 	    vecs, MAX_WSABUFS, &chainp, 1);
275*663afb9bSAndroid Build Coastguard Worker 	for (i=0;i<nvecs;++i) {
276*663afb9bSAndroid Build Coastguard Worker 		WSABUF_FROM_EVBUFFER_IOV(
277*663afb9bSAndroid Build Coastguard Worker 			&buf_o->buffers[i],
278*663afb9bSAndroid Build Coastguard Worker 			&vecs[i]);
279*663afb9bSAndroid Build Coastguard Worker 	}
280*663afb9bSAndroid Build Coastguard Worker 
281*663afb9bSAndroid Build Coastguard Worker 	buf_o->n_buffers = nvecs;
282*663afb9bSAndroid Build Coastguard Worker 	buf_o->first_pinned = chain = *chainp;
283*663afb9bSAndroid Build Coastguard Worker 
284*663afb9bSAndroid Build Coastguard Worker 	npin=0;
285*663afb9bSAndroid Build Coastguard Worker 	for ( ; chain; chain = chain->next) {
286*663afb9bSAndroid Build Coastguard Worker 		evbuffer_chain_pin_(chain, EVBUFFER_MEM_PINNED_R);
287*663afb9bSAndroid Build Coastguard Worker 		++npin;
288*663afb9bSAndroid Build Coastguard Worker 	}
289*663afb9bSAndroid Build Coastguard Worker 	EVUTIL_ASSERT(npin == nvecs);
290*663afb9bSAndroid Build Coastguard Worker 
291*663afb9bSAndroid Build Coastguard Worker 	evbuffer_incref_(buf);
292*663afb9bSAndroid Build Coastguard Worker 	if (WSARecv(buf_o->fd, buf_o->buffers, nvecs, &bytesRead, &flags,
293*663afb9bSAndroid Build Coastguard Worker 		    &ol->overlapped, NULL)) {
294*663afb9bSAndroid Build Coastguard Worker 		int error = WSAGetLastError();
295*663afb9bSAndroid Build Coastguard Worker 		if (error != WSA_IO_PENDING) {
296*663afb9bSAndroid Build Coastguard Worker 			/* An actual error. */
297*663afb9bSAndroid Build Coastguard Worker 			pin_release(buf_o, EVBUFFER_MEM_PINNED_R);
298*663afb9bSAndroid Build Coastguard Worker 			evbuffer_unfreeze(buf, 0);
299*663afb9bSAndroid Build Coastguard Worker 			evbuffer_free(buf); /* decref */
300*663afb9bSAndroid Build Coastguard Worker 			goto done;
301*663afb9bSAndroid Build Coastguard Worker 		}
302*663afb9bSAndroid Build Coastguard Worker 	}
303*663afb9bSAndroid Build Coastguard Worker 
304*663afb9bSAndroid Build Coastguard Worker 	buf_o->read_in_progress = 1;
305*663afb9bSAndroid Build Coastguard Worker 	r = 0;
306*663afb9bSAndroid Build Coastguard Worker done:
307*663afb9bSAndroid Build Coastguard Worker 	EVBUFFER_UNLOCK(buf);
308*663afb9bSAndroid Build Coastguard Worker 	return r;
309*663afb9bSAndroid Build Coastguard Worker }
310*663afb9bSAndroid Build Coastguard Worker 
311*663afb9bSAndroid Build Coastguard Worker evutil_socket_t
evbuffer_overlapped_get_fd_(struct evbuffer * buf)312*663afb9bSAndroid Build Coastguard Worker evbuffer_overlapped_get_fd_(struct evbuffer *buf)
313*663afb9bSAndroid Build Coastguard Worker {
314*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
315*663afb9bSAndroid Build Coastguard Worker 	return buf_o ? buf_o->fd : -1;
316*663afb9bSAndroid Build Coastguard Worker }
317*663afb9bSAndroid Build Coastguard Worker 
318*663afb9bSAndroid Build Coastguard Worker void
evbuffer_overlapped_set_fd_(struct evbuffer * buf,evutil_socket_t fd)319*663afb9bSAndroid Build Coastguard Worker evbuffer_overlapped_set_fd_(struct evbuffer *buf, evutil_socket_t fd)
320*663afb9bSAndroid Build Coastguard Worker {
321*663afb9bSAndroid Build Coastguard Worker 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
322*663afb9bSAndroid Build Coastguard Worker 	EVBUFFER_LOCK(buf);
323*663afb9bSAndroid Build Coastguard Worker 	/* XXX is this right?, should it cancel current I/O operations? */
324*663afb9bSAndroid Build Coastguard Worker 	if (buf_o)
325*663afb9bSAndroid Build Coastguard Worker 		buf_o->fd = fd;
326*663afb9bSAndroid Build Coastguard Worker 	EVBUFFER_UNLOCK(buf);
327*663afb9bSAndroid Build Coastguard Worker }
328