xref: /netbsd/lib/libc/isc/ev_streams.c (revision 6550d01e) 
1 /*	$NetBSD: ev_streams.c,v 1.6 2009/04/12 17:07:17 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5  * Copyright (c) 1996-1999 by Internet Software Consortium
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 /* ev_streams.c - implement asynch stream file IO for the eventlib
21  * vix 04mar96 [initial]
22  */
23 
24 #include <sys/cdefs.h>
25 #if !defined(LINT) && !defined(CODECENTER) && !defined(lint)
26 #ifdef notdef
27 static const char rcsid[] = "Id: ev_streams.c,v 1.5 2005/04/27 04:56:36 sra Exp";
28 #else
29 __RCSID("$NetBSD: ev_streams.c,v 1.6 2009/04/12 17:07:17 christos Exp $");
30 #endif
31 #endif
32 
33 #include "port_before.h"
34 #include "fd_setsize.h"
35 
36 #include <sys/types.h>
37 #include <sys/uio.h>
38 
39 #include <errno.h>
40 
41 #include <isc/eventlib.h>
42 #include <isc/assertions.h>
43 #include "eventlib_p.h"
44 
45 #include "port_after.h"
46 
47 #ifndef _LIBC
48 static int	copyvec(evStream *str, const struct iovec *iov, int iocnt);
49 static void	consume(evStream *str, size_t bytes);
50 static void	done(evContext opaqueCtx, evStream *str);
51 static void	writable(evContext opaqueCtx, void *uap, int fd, int evmask);
52 static void	readable(evContext opaqueCtx, void *uap, int fd, int evmask);
53 #endif
54 
55 struct iovec
56 evConsIovec(void *buf, size_t cnt) {
57 	struct iovec ret;
58 
59 	memset(&ret, 0xf5, sizeof ret);
60 	ret.iov_base = buf;
61 	ret.iov_len = cnt;
62 	return (ret);
63 }
64 
65 #ifndef _LIBC
66 int
67 evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
68 	evStreamFunc func, void *uap, evStreamID *id)
69 {
70 	evContext_p *ctx = opaqueCtx.opaque;
71 	evStream *new;
72 	int save;
73 
74 	OKNEW(new);
75 	new->func = func;
76 	new->uap = uap;
77 	new->fd = fd;
78 	new->flags = 0;
79 	if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
80 		goto free;
81 	if (copyvec(new, iov, iocnt) < 0)
82 		goto free;
83 	new->prevDone = NULL;
84 	new->nextDone = NULL;
85 	if (ctx->streams != NULL)
86 		ctx->streams->prev = new;
87 	new->prev = NULL;
88 	new->next = ctx->streams;
89 	ctx->streams = new;
90 	if (id != NULL)
91 		id->opaque = new;
92 	return (0);
93  free:
94 	save = errno;
95 	FREE(new);
96 	errno = save;
97 	return (-1);
98 }
99 
100 int
101 evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
102        evStreamFunc func, void *uap, evStreamID *id)
103 {
104 	evContext_p *ctx = opaqueCtx.opaque;
105 	evStream *new;
106 	int save;
107 
108 	OKNEW(new);
109 	new->func = func;
110 	new->uap = uap;
111 	new->fd = fd;
112 	new->flags = 0;
113 	if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
114 		goto free;
115 	if (copyvec(new, iov, iocnt) < 0)
116 		goto free;
117 	new->prevDone = NULL;
118 	new->nextDone = NULL;
119 	if (ctx->streams != NULL)
120 		ctx->streams->prev = new;
121 	new->prev = NULL;
122 	new->next = ctx->streams;
123 	ctx->streams = new;
124 	if (id)
125 		id->opaque = new;
126 	return (0);
127  free:
128 	save = errno;
129 	FREE(new);
130 	errno = save;
131 	return (-1);
132 }
133 
134 int
135 evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
136 	evStream *str = id.opaque;
137 
138 	UNUSED(opaqueCtx);
139 
140 	str->timer = timer;
141 	str->flags |= EV_STR_TIMEROK;
142 	return (0);
143 }
144 
145 int
146 evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
147 	evStream *str = id.opaque;
148 
149 	UNUSED(opaqueCtx);
150 
151 	str->flags &= ~EV_STR_TIMEROK;
152 	return (0);
153 }
154 
155 int
156 evCancelRW(evContext opaqueCtx, evStreamID id) {
157 	evContext_p *ctx = opaqueCtx.opaque;
158 	evStream *old = id.opaque;
159 
160 	/*
161 	 * The streams list is doubly threaded.  First, there's ctx->streams
162 	 * that's used by evDestroy() to find and cancel all streams.  Second,
163 	 * there's ctx->strDone (head) and ctx->strLast (tail) which thread
164 	 * through the potentially smaller number of "IO completed" streams,
165 	 * used in evGetNext() to avoid scanning the entire list.
166 	 */
167 
168 	/* Unlink from ctx->streams. */
169 	if (old->prev != NULL)
170 		old->prev->next = old->next;
171 	else
172 		ctx->streams = old->next;
173 	if (old->next != NULL)
174 		old->next->prev = old->prev;
175 
176 	/*
177 	 * If 'old' is on the ctx->strDone list, remove it.  Update
178 	 * ctx->strLast if necessary.
179 	 */
180 	if (old->prevDone == NULL && old->nextDone == NULL) {
181 		/*
182 		 * Either 'old' is the only item on the done list, or it's
183 		 * not on the done list.  If the former, then we unlink it
184 		 * from the list.  If the latter, we leave the list alone.
185 		 */
186 		if (ctx->strDone == old) {
187 			ctx->strDone = NULL;
188 			ctx->strLast = NULL;
189 		}
190 	} else {
191 		if (old->prevDone != NULL)
192 			old->prevDone->nextDone = old->nextDone;
193 		else
194 			ctx->strDone = old->nextDone;
195 		if (old->nextDone != NULL)
196 			old->nextDone->prevDone = old->prevDone;
197 		else
198 			ctx->strLast = old->prevDone;
199 	}
200 
201 	/* Deallocate the stream. */
202 	if (old->file.opaque)
203 		evDeselectFD(opaqueCtx, old->file);
204 	memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
205 	FREE(old);
206 	return (0);
207 }
208 
209 /* Copy a scatter/gather vector and initialize a stream handler's IO. */
210 static int
211 copyvec(evStream *str, const struct iovec *iov, int iocnt) {
212 	int i;
213 
214 	str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
215 	if (str->iovOrig == NULL) {
216 		errno = ENOMEM;
217 		return (-1);
218 	}
219 	str->ioTotal = 0;
220 	for (i = 0; i < iocnt; i++) {
221 		str->iovOrig[i] = iov[i];
222 		str->ioTotal += iov[i].iov_len;
223 	}
224 	str->iovOrigCount = iocnt;
225 	str->iovCur = str->iovOrig;
226 	str->iovCurCount = str->iovOrigCount;
227 	str->ioDone = 0;
228 	return (0);
229 }
230 
231 /* Pull off or truncate lead iovec(s). */
232 static void
233 consume(evStream *str, size_t bytes) {
234 	while (bytes > 0U) {
235 		if (bytes < (size_t)str->iovCur->iov_len) {
236 			str->iovCur->iov_len -= bytes;
237 			str->iovCur->iov_base = (void *)
238 				((u_char *)str->iovCur->iov_base + bytes);
239 			str->ioDone += bytes;
240 			bytes = 0;
241 		} else {
242 			bytes -= str->iovCur->iov_len;
243 			str->ioDone += str->iovCur->iov_len;
244 			str->iovCur++;
245 			str->iovCurCount--;
246 		}
247 	}
248 }
249 
250 /* Add a stream to Done list and deselect the FD. */
251 static void
252 done(evContext opaqueCtx, evStream *str) {
253 	evContext_p *ctx = opaqueCtx.opaque;
254 
255 	if (ctx->strLast != NULL) {
256 		str->prevDone = ctx->strLast;
257 		ctx->strLast->nextDone = str;
258 		ctx->strLast = str;
259 	} else {
260 		INSIST(ctx->strDone == NULL);
261 		ctx->strDone = ctx->strLast = str;
262 	}
263 	evDeselectFD(opaqueCtx, str->file);
264 	str->file.opaque = NULL;
265 	/* evDrop() will call evCancelRW() on us. */
266 }
267 
268 /* Dribble out some bytes on the stream.  (Called by evDispatch().) */
269 static void
270 writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
271 	evStream *str = uap;
272 	int bytes;
273 
274 	UNUSED(evmask);
275 
276 	bytes = writev(fd, str->iovCur, str->iovCurCount);
277 	if (bytes > 0) {
278 		if ((str->flags & EV_STR_TIMEROK) != 0)
279 			evTouchIdleTimer(opaqueCtx, str->timer);
280 		consume(str, bytes);
281 	} else {
282 		if (bytes < 0 && errno != EINTR) {
283 			str->ioDone = -1;
284 			str->ioErrno = errno;
285 		}
286 	}
287 	if (str->ioDone == -1 || str->ioDone == str->ioTotal)
288 		done(opaqueCtx, str);
289 }
290 
291 /* Scoop up some bytes from the stream.  (Called by evDispatch().) */
292 static void
293 readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
294 	evStream *str = uap;
295 	int bytes;
296 
297 	UNUSED(evmask);
298 
299 	bytes = readv(fd, str->iovCur, str->iovCurCount);
300 	if (bytes > 0) {
301 		if ((str->flags & EV_STR_TIMEROK) != 0)
302 			evTouchIdleTimer(opaqueCtx, str->timer);
303 		consume(str, bytes);
304 	} else {
305 		if (bytes == 0)
306 			str->ioDone = 0;
307 		else {
308 			if (errno != EINTR) {
309 				str->ioDone = -1;
310 				str->ioErrno = errno;
311 			}
312 		}
313 	}
314 	if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
315 		done(opaqueCtx, str);
316 }
317 #endif
318 
319 /*! \file */
320