ev_streams.c revision 270838 
1/*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996-1999 by Internet Software Consortium
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* ev_streams.c - implement asynch stream file IO for the eventlib
19 * vix 04mar96 [initial]
20 */
21
22#if !defined(LINT) && !defined(CODECENTER)
23static const char rcsid[] = "$Id: ev_streams.c,v 1.5 2005/04/27 04:56:36 sra Exp $";
24#endif
25#include <sys/cdefs.h>
26__FBSDID("$FreeBSD: stable/10/lib/libc/isc/ev_streams.c 270838 2014-08-30 10:16:25Z ume $");
27
28#include "port_before.h"
29#ifndef _LIBC
30#include "fd_setsize.h"
31#endif
32
33#include <sys/types.h>
34#include <sys/uio.h>
35
36#include <errno.h>
37
38#include <isc/eventlib.h>
39#ifndef _LIBC
40#include <isc/assertions.h>
41#endif
42#include "eventlib_p.h"
43
44#include "port_after.h"
45
46#ifndef _LIBC
47static int	copyvec(evStream *str, const struct iovec *iov, int iocnt);
48static void	consume(evStream *str, size_t bytes);
49static void	done(evContext opaqueCtx, evStream *str);
50static void	writable(evContext opaqueCtx, void *uap, int fd, int evmask);
51static void	readable(evContext opaqueCtx, void *uap, int fd, int evmask);
52#endif
53
54struct iovec
55evConsIovec(void *buf, size_t cnt) {
56	struct iovec ret;
57
58	memset(&ret, 0xf5, sizeof ret);
59	ret.iov_base = buf;
60	ret.iov_len = cnt;
61	return (ret);
62}
63
64#ifndef _LIBC
65int
66evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
67	evStreamFunc func, void *uap, evStreamID *id)
68{
69	evContext_p *ctx = opaqueCtx.opaque;
70	evStream *new;
71	int save;
72
73	OKNEW(new);
74	new->func = func;
75	new->uap = uap;
76	new->fd = fd;
77	new->flags = 0;
78	if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
79		goto free;
80	if (copyvec(new, iov, iocnt) < 0)
81		goto free;
82	new->prevDone = NULL;
83	new->nextDone = NULL;
84	if (ctx->streams != NULL)
85		ctx->streams->prev = new;
86	new->prev = NULL;
87	new->next = ctx->streams;
88	ctx->streams = new;
89	if (id != NULL)
90		id->opaque = new;
91	return (0);
92 free:
93	save = errno;
94	FREE(new);
95	errno = save;
96	return (-1);
97}
98
99int
100evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
101       evStreamFunc func, void *uap, evStreamID *id)
102{
103	evContext_p *ctx = opaqueCtx.opaque;
104	evStream *new;
105	int save;
106
107	OKNEW(new);
108	new->func = func;
109	new->uap = uap;
110	new->fd = fd;
111	new->flags = 0;
112	if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
113		goto free;
114	if (copyvec(new, iov, iocnt) < 0)
115		goto free;
116	new->prevDone = NULL;
117	new->nextDone = NULL;
118	if (ctx->streams != NULL)
119		ctx->streams->prev = new;
120	new->prev = NULL;
121	new->next = ctx->streams;
122	ctx->streams = new;
123	if (id)
124		id->opaque = new;
125	return (0);
126 free:
127	save = errno;
128	FREE(new);
129	errno = save;
130	return (-1);
131}
132
133int
134evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
135	evStream *str = id.opaque;
136
137	UNUSED(opaqueCtx);
138
139	str->timer = timer;
140	str->flags |= EV_STR_TIMEROK;
141	return (0);
142}
143
144int
145evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
146	evStream *str = id.opaque;
147
148	UNUSED(opaqueCtx);
149
150	str->flags &= ~EV_STR_TIMEROK;
151	return (0);
152}
153
154int
155evCancelRW(evContext opaqueCtx, evStreamID id) {
156	evContext_p *ctx = opaqueCtx.opaque;
157	evStream *old = id.opaque;
158
159	/*
160	 * The streams list is doubly threaded.  First, there's ctx->streams
161	 * that's used by evDestroy() to find and cancel all streams.  Second,
162	 * there's ctx->strDone (head) and ctx->strLast (tail) which thread
163	 * through the potentially smaller number of "IO completed" streams,
164	 * used in evGetNext() to avoid scanning the entire list.
165	 */
166
167	/* Unlink from ctx->streams. */
168	if (old->prev != NULL)
169		old->prev->next = old->next;
170	else
171		ctx->streams = old->next;
172	if (old->next != NULL)
173		old->next->prev = old->prev;
174
175	/*
176	 * If 'old' is on the ctx->strDone list, remove it.  Update
177	 * ctx->strLast if necessary.
178	 */
179	if (old->prevDone == NULL && old->nextDone == NULL) {
180		/*
181		 * Either 'old' is the only item on the done list, or it's
182		 * not on the done list.  If the former, then we unlink it
183		 * from the list.  If the latter, we leave the list alone.
184		 */
185		if (ctx->strDone == old) {
186			ctx->strDone = NULL;
187			ctx->strLast = NULL;
188		}
189	} else {
190		if (old->prevDone != NULL)
191			old->prevDone->nextDone = old->nextDone;
192		else
193			ctx->strDone = old->nextDone;
194		if (old->nextDone != NULL)
195			old->nextDone->prevDone = old->prevDone;
196		else
197			ctx->strLast = old->prevDone;
198	}
199
200	/* Deallocate the stream. */
201	if (old->file.opaque)
202		evDeselectFD(opaqueCtx, old->file);
203	memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
204	FREE(old);
205	return (0);
206}
207
208/* Copy a scatter/gather vector and initialize a stream handler's IO. */
209static int
210copyvec(evStream *str, const struct iovec *iov, int iocnt) {
211	int i;
212
213	str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
214	if (str->iovOrig == NULL) {
215		errno = ENOMEM;
216		return (-1);
217	}
218	str->ioTotal = 0;
219	for (i = 0; i < iocnt; i++) {
220		str->iovOrig[i] = iov[i];
221		str->ioTotal += iov[i].iov_len;
222	}
223	str->iovOrigCount = iocnt;
224	str->iovCur = str->iovOrig;
225	str->iovCurCount = str->iovOrigCount;
226	str->ioDone = 0;
227	return (0);
228}
229
230/* Pull off or truncate lead iovec(s). */
231static void
232consume(evStream *str, size_t bytes) {
233	while (bytes > 0U) {
234		if (bytes < (size_t)str->iovCur->iov_len) {
235			str->iovCur->iov_len -= bytes;
236			str->iovCur->iov_base = (void *)
237				((u_char *)str->iovCur->iov_base + bytes);
238			str->ioDone += bytes;
239			bytes = 0;
240		} else {
241			bytes -= str->iovCur->iov_len;
242			str->ioDone += str->iovCur->iov_len;
243			str->iovCur++;
244			str->iovCurCount--;
245		}
246	}
247}
248
249/* Add a stream to Done list and deselect the FD. */
250static void
251done(evContext opaqueCtx, evStream *str) {
252	evContext_p *ctx = opaqueCtx.opaque;
253
254	if (ctx->strLast != NULL) {
255		str->prevDone = ctx->strLast;
256		ctx->strLast->nextDone = str;
257		ctx->strLast = str;
258	} else {
259		INSIST(ctx->strDone == NULL);
260		ctx->strDone = ctx->strLast = str;
261	}
262	evDeselectFD(opaqueCtx, str->file);
263	str->file.opaque = NULL;
264	/* evDrop() will call evCancelRW() on us. */
265}
266
267/* Dribble out some bytes on the stream.  (Called by evDispatch().) */
268static void
269writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
270	evStream *str = uap;
271	int bytes;
272
273	UNUSED(evmask);
274
275	bytes = writev(fd, str->iovCur, str->iovCurCount);
276	if (bytes > 0) {
277		if ((str->flags & EV_STR_TIMEROK) != 0)
278			evTouchIdleTimer(opaqueCtx, str->timer);
279		consume(str, bytes);
280	} else {
281		if (bytes < 0 && errno != EINTR) {
282			str->ioDone = -1;
283			str->ioErrno = errno;
284		}
285	}
286	if (str->ioDone == -1 || str->ioDone == str->ioTotal)
287		done(opaqueCtx, str);
288}
289
290/* Scoop up some bytes from the stream.  (Called by evDispatch().) */
291static void
292readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
293	evStream *str = uap;
294	int bytes;
295
296	UNUSED(evmask);
297
298	bytes = readv(fd, str->iovCur, str->iovCurCount);
299	if (bytes > 0) {
300		if ((str->flags & EV_STR_TIMEROK) != 0)
301			evTouchIdleTimer(opaqueCtx, str->timer);
302		consume(str, bytes);
303	} else {
304		if (bytes == 0)
305			str->ioDone = 0;
306		else {
307			if (errno != EINTR) {
308				str->ioDone = -1;
309				str->ioErrno = errno;
310			}
311		}
312	}
313	if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
314		done(opaqueCtx, str);
315}
316#endif
317
318/*! \file */
319