xref: /freebsd/lib/libc/isc/ev_streams.c (revision c697fb7f) 
1 /*-
2  * SPDX-License-Identifier: ISC
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 #if !defined(LINT) && !defined(CODECENTER)
25 static const char rcsid[] = "$Id: ev_streams.c,v 1.5 2005/04/27 04:56:36 sra Exp $";
26 #endif
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "port_before.h"
31 #ifndef _LIBC
32 #include "fd_setsize.h"
33 #endif
34 
35 #include <sys/types.h>
36 #include <sys/uio.h>
37 
38 #include <errno.h>
39 
40 #include <isc/eventlib.h>
41 #ifndef _LIBC
42 #include <isc/assertions.h>
43 #endif
44 #include "eventlib_p.h"
45 
46 #include "port_after.h"
47 
48 #ifndef _LIBC
49 static int	copyvec(evStream *str, const struct iovec *iov, int iocnt);
50 static void	consume(evStream *str, size_t bytes);
51 static void	done(evContext opaqueCtx, evStream *str);
52 static void	writable(evContext opaqueCtx, void *uap, int fd, int evmask);
53 static void	readable(evContext opaqueCtx, void *uap, int fd, int evmask);
54 #endif
55 
56 struct iovec
57 evConsIovec(void *buf, size_t cnt) {
58 	struct iovec ret;
59 
60 	memset(&ret, 0xf5, sizeof ret);
61 	ret.iov_base = buf;
62 	ret.iov_len = cnt;
63 	return (ret);
64 }
65 
66 #ifndef _LIBC
67 int
68 evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
69 	evStreamFunc func, void *uap, evStreamID *id)
70 {
71 	evContext_p *ctx = opaqueCtx.opaque;
72 	evStream *new;
73 	int save;
74 
75 	OKNEW(new);
76 	new->func = func;
77 	new->uap = uap;
78 	new->fd = fd;
79 	new->flags = 0;
80 	if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
81 		goto free;
82 	if (copyvec(new, iov, iocnt) < 0)
83 		goto free;
84 	new->prevDone = NULL;
85 	new->nextDone = NULL;
86 	if (ctx->streams != NULL)
87 		ctx->streams->prev = new;
88 	new->prev = NULL;
89 	new->next = ctx->streams;
90 	ctx->streams = new;
91 	if (id != NULL)
92 		id->opaque = new;
93 	return (0);
94  free:
95 	save = errno;
96 	FREE(new);
97 	errno = save;
98 	return (-1);
99 }
100 
101 int
102 evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
103        evStreamFunc func, void *uap, evStreamID *id)
104 {
105 	evContext_p *ctx = opaqueCtx.opaque;
106 	evStream *new;
107 	int save;
108 
109 	OKNEW(new);
110 	new->func = func;
111 	new->uap = uap;
112 	new->fd = fd;
113 	new->flags = 0;
114 	if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
115 		goto free;
116 	if (copyvec(new, iov, iocnt) < 0)
117 		goto free;
118 	new->prevDone = NULL;
119 	new->nextDone = NULL;
120 	if (ctx->streams != NULL)
121 		ctx->streams->prev = new;
122 	new->prev = NULL;
123 	new->next = ctx->streams;
124 	ctx->streams = new;
125 	if (id)
126 		id->opaque = new;
127 	return (0);
128  free:
129 	save = errno;
130 	FREE(new);
131 	errno = save;
132 	return (-1);
133 }
134 
135 int
136 evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
137 	evStream *str = id.opaque;
138 
139 	UNUSED(opaqueCtx);
140 
141 	str->timer = timer;
142 	str->flags |= EV_STR_TIMEROK;
143 	return (0);
144 }
145 
146 int
147 evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
148 	evStream *str = id.opaque;
149 
150 	UNUSED(opaqueCtx);
151 
152 	str->flags &= ~EV_STR_TIMEROK;
153 	return (0);
154 }
155 
156 int
157 evCancelRW(evContext opaqueCtx, evStreamID id) {
158 	evContext_p *ctx = opaqueCtx.opaque;
159 	evStream *old = id.opaque;
160 
161 	/*
162 	 * The streams list is doubly threaded.  First, there's ctx->streams
163 	 * that's used by evDestroy() to find and cancel all streams.  Second,
164 	 * there's ctx->strDone (head) and ctx->strLast (tail) which thread
165 	 * through the potentially smaller number of "IO completed" streams,
166 	 * used in evGetNext() to avoid scanning the entire list.
167 	 */
168 
169 	/* Unlink from ctx->streams. */
170 	if (old->prev != NULL)
171 		old->prev->next = old->next;
172 	else
173 		ctx->streams = old->next;
174 	if (old->next != NULL)
175 		old->next->prev = old->prev;
176 
177 	/*
178 	 * If 'old' is on the ctx->strDone list, remove it.  Update
179 	 * ctx->strLast if necessary.
180 	 */
181 	if (old->prevDone == NULL && old->nextDone == NULL) {
182 		/*
183 		 * Either 'old' is the only item on the done list, or it's
184 		 * not on the done list.  If the former, then we unlink it
185 		 * from the list.  If the latter, we leave the list alone.
186 		 */
187 		if (ctx->strDone == old) {
188 			ctx->strDone = NULL;
189 			ctx->strLast = NULL;
190 		}
191 	} else {
192 		if (old->prevDone != NULL)
193 			old->prevDone->nextDone = old->nextDone;
194 		else
195 			ctx->strDone = old->nextDone;
196 		if (old->nextDone != NULL)
197 			old->nextDone->prevDone = old->prevDone;
198 		else
199 			ctx->strLast = old->prevDone;
200 	}
201 
202 	/* Deallocate the stream. */
203 	if (old->file.opaque)
204 		evDeselectFD(opaqueCtx, old->file);
205 	memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
206 	FREE(old);
207 	return (0);
208 }
209 
210 /* Copy a scatter/gather vector and initialize a stream handler's IO. */
211 static int
212 copyvec(evStream *str, const struct iovec *iov, int iocnt) {
213 	int i;
214 
215 	str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
216 	if (str->iovOrig == NULL) {
217 		errno = ENOMEM;
218 		return (-1);
219 	}
220 	str->ioTotal = 0;
221 	for (i = 0; i < iocnt; i++) {
222 		str->iovOrig[i] = iov[i];
223 		str->ioTotal += iov[i].iov_len;
224 	}
225 	str->iovOrigCount = iocnt;
226 	str->iovCur = str->iovOrig;
227 	str->iovCurCount = str->iovOrigCount;
228 	str->ioDone = 0;
229 	return (0);
230 }
231 
232 /* Pull off or truncate lead iovec(s). */
233 static void
234 consume(evStream *str, size_t bytes) {
235 	while (bytes > 0U) {
236 		if (bytes < (size_t)str->iovCur->iov_len) {
237 			str->iovCur->iov_len -= bytes;
238 			str->iovCur->iov_base = (void *)
239 				((u_char *)str->iovCur->iov_base + bytes);
240 			str->ioDone += bytes;
241 			bytes = 0;
242 		} else {
243 			bytes -= str->iovCur->iov_len;
244 			str->ioDone += str->iovCur->iov_len;
245 			str->iovCur++;
246 			str->iovCurCount--;
247 		}
248 	}
249 }
250 
251 /* Add a stream to Done list and deselect the FD. */
252 static void
253 done(evContext opaqueCtx, evStream *str) {
254 	evContext_p *ctx = opaqueCtx.opaque;
255 
256 	if (ctx->strLast != NULL) {
257 		str->prevDone = ctx->strLast;
258 		ctx->strLast->nextDone = str;
259 		ctx->strLast = str;
260 	} else {
261 		INSIST(ctx->strDone == NULL);
262 		ctx->strDone = ctx->strLast = str;
263 	}
264 	evDeselectFD(opaqueCtx, str->file);
265 	str->file.opaque = NULL;
266 	/* evDrop() will call evCancelRW() on us. */
267 }
268 
269 /* Dribble out some bytes on the stream.  (Called by evDispatch().) */
270 static void
271 writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
272 	evStream *str = uap;
273 	int bytes;
274 
275 	UNUSED(evmask);
276 
277 	bytes = writev(fd, str->iovCur, str->iovCurCount);
278 	if (bytes > 0) {
279 		if ((str->flags & EV_STR_TIMEROK) != 0)
280 			evTouchIdleTimer(opaqueCtx, str->timer);
281 		consume(str, bytes);
282 	} else {
283 		if (bytes < 0 && errno != EINTR) {
284 			str->ioDone = -1;
285 			str->ioErrno = errno;
286 		}
287 	}
288 	if (str->ioDone == -1 || str->ioDone == str->ioTotal)
289 		done(opaqueCtx, str);
290 }
291 
292 /* Scoop up some bytes from the stream.  (Called by evDispatch().) */
293 static void
294 readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
295 	evStream *str = uap;
296 	int bytes;
297 
298 	UNUSED(evmask);
299 
300 	bytes = readv(fd, str->iovCur, str->iovCurCount);
301 	if (bytes > 0) {
302 		if ((str->flags & EV_STR_TIMEROK) != 0)
303 			evTouchIdleTimer(opaqueCtx, str->timer);
304 		consume(str, bytes);
305 	} else {
306 		if (bytes == 0)
307 			str->ioDone = 0;
308 		else {
309 			if (errno != EINTR) {
310 				str->ioDone = -1;
311 				str->ioErrno = errno;
312 			}
313 		}
314 	}
315 	if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
316 		done(opaqueCtx, str);
317 }
318 #endif
319 
320 /*! \file */
321