xref: /freebsd/lib/libc/isc/ev_streams.c (revision 2008043f386721d58158e37e0d7e50df8095942d) 
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 "port_before.h"
28 #ifndef _LIBC
29 #include "fd_setsize.h"
30 #endif
31 
32 #include <sys/types.h>
33 #include <sys/uio.h>
34 
35 #include <errno.h>
36 
37 #include <isc/eventlib.h>
38 #ifndef _LIBC
39 #include <isc/assertions.h>
40 #endif
41 #include "eventlib_p.h"
42 
43 #include "port_after.h"
44 
45 #ifndef _LIBC
46 static int	copyvec(evStream *str, const struct iovec *iov, int iocnt);
47 static void	consume(evStream *str, size_t bytes);
48 static void	done(evContext opaqueCtx, evStream *str);
49 static void	writable(evContext opaqueCtx, void *uap, int fd, int evmask);
50 static void	readable(evContext opaqueCtx, void *uap, int fd, int evmask);
51 #endif
52 
53 struct iovec
54 evConsIovec(void *buf, size_t cnt) {
55 	struct iovec ret;
56 
57 	memset(&ret, 0xf5, sizeof ret);
58 	ret.iov_base = buf;
59 	ret.iov_len = cnt;
60 	return (ret);
61 }
62 
63 #ifndef _LIBC
64 int
65 evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
66 	evStreamFunc func, void *uap, evStreamID *id)
67 {
68 	evContext_p *ctx = opaqueCtx.opaque;
69 	evStream *new;
70 	int save;
71 
72 	OKNEW(new);
73 	new->func = func;
74 	new->uap = uap;
75 	new->fd = fd;
76 	new->flags = 0;
77 	if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
78 		goto free;
79 	if (copyvec(new, iov, iocnt) < 0)
80 		goto free;
81 	new->prevDone = NULL;
82 	new->nextDone = NULL;
83 	if (ctx->streams != NULL)
84 		ctx->streams->prev = new;
85 	new->prev = NULL;
86 	new->next = ctx->streams;
87 	ctx->streams = new;
88 	if (id != NULL)
89 		id->opaque = new;
90 	return (0);
91  free:
92 	save = errno;
93 	FREE(new);
94 	errno = save;
95 	return (-1);
96 }
97 
98 int
99 evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
100        evStreamFunc func, void *uap, evStreamID *id)
101 {
102 	evContext_p *ctx = opaqueCtx.opaque;
103 	evStream *new;
104 	int save;
105 
106 	OKNEW(new);
107 	new->func = func;
108 	new->uap = uap;
109 	new->fd = fd;
110 	new->flags = 0;
111 	if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
112 		goto free;
113 	if (copyvec(new, iov, iocnt) < 0)
114 		goto free;
115 	new->prevDone = NULL;
116 	new->nextDone = NULL;
117 	if (ctx->streams != NULL)
118 		ctx->streams->prev = new;
119 	new->prev = NULL;
120 	new->next = ctx->streams;
121 	ctx->streams = new;
122 	if (id)
123 		id->opaque = new;
124 	return (0);
125  free:
126 	save = errno;
127 	FREE(new);
128 	errno = save;
129 	return (-1);
130 }
131 
132 int
133 evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
134 	evStream *str = id.opaque;
135 
136 	UNUSED(opaqueCtx);
137 
138 	str->timer = timer;
139 	str->flags |= EV_STR_TIMEROK;
140 	return (0);
141 }
142 
143 int
144 evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
145 	evStream *str = id.opaque;
146 
147 	UNUSED(opaqueCtx);
148 
149 	str->flags &= ~EV_STR_TIMEROK;
150 	return (0);
151 }
152 
153 int
154 evCancelRW(evContext opaqueCtx, evStreamID id) {
155 	evContext_p *ctx = opaqueCtx.opaque;
156 	evStream *old = id.opaque;
157 
158 	/*
159 	 * The streams list is doubly threaded.  First, there's ctx->streams
160 	 * that's used by evDestroy() to find and cancel all streams.  Second,
161 	 * there's ctx->strDone (head) and ctx->strLast (tail) which thread
162 	 * through the potentially smaller number of "IO completed" streams,
163 	 * used in evGetNext() to avoid scanning the entire list.
164 	 */
165 
166 	/* Unlink from ctx->streams. */
167 	if (old->prev != NULL)
168 		old->prev->next = old->next;
169 	else
170 		ctx->streams = old->next;
171 	if (old->next != NULL)
172 		old->next->prev = old->prev;
173 
174 	/*
175 	 * If 'old' is on the ctx->strDone list, remove it.  Update
176 	 * ctx->strLast if necessary.
177 	 */
178 	if (old->prevDone == NULL && old->nextDone == NULL) {
179 		/*
180 		 * Either 'old' is the only item on the done list, or it's
181 		 * not on the done list.  If the former, then we unlink it
182 		 * from the list.  If the latter, we leave the list alone.
183 		 */
184 		if (ctx->strDone == old) {
185 			ctx->strDone = NULL;
186 			ctx->strLast = NULL;
187 		}
188 	} else {
189 		if (old->prevDone != NULL)
190 			old->prevDone->nextDone = old->nextDone;
191 		else
192 			ctx->strDone = old->nextDone;
193 		if (old->nextDone != NULL)
194 			old->nextDone->prevDone = old->prevDone;
195 		else
196 			ctx->strLast = old->prevDone;
197 	}
198 
199 	/* Deallocate the stream. */
200 	if (old->file.opaque)
201 		evDeselectFD(opaqueCtx, old->file);
202 	memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
203 	FREE(old);
204 	return (0);
205 }
206 
207 /* Copy a scatter/gather vector and initialize a stream handler's IO. */
208 static int
209 copyvec(evStream *str, const struct iovec *iov, int iocnt) {
210 	int i;
211 
212 	str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
213 	if (str->iovOrig == NULL) {
214 		errno = ENOMEM;
215 		return (-1);
216 	}
217 	str->ioTotal = 0;
218 	for (i = 0; i < iocnt; i++) {
219 		str->iovOrig[i] = iov[i];
220 		str->ioTotal += iov[i].iov_len;
221 	}
222 	str->iovOrigCount = iocnt;
223 	str->iovCur = str->iovOrig;
224 	str->iovCurCount = str->iovOrigCount;
225 	str->ioDone = 0;
226 	return (0);
227 }
228 
229 /* Pull off or truncate lead iovec(s). */
230 static void
231 consume(evStream *str, size_t bytes) {
232 	while (bytes > 0U) {
233 		if (bytes < (size_t)str->iovCur->iov_len) {
234 			str->iovCur->iov_len -= bytes;
235 			str->iovCur->iov_base = (void *)
236 				((u_char *)str->iovCur->iov_base + bytes);
237 			str->ioDone += bytes;
238 			bytes = 0;
239 		} else {
240 			bytes -= str->iovCur->iov_len;
241 			str->ioDone += str->iovCur->iov_len;
242 			str->iovCur++;
243 			str->iovCurCount--;
244 		}
245 	}
246 }
247 
248 /* Add a stream to Done list and deselect the FD. */
249 static void
250 done(evContext opaqueCtx, evStream *str) {
251 	evContext_p *ctx = opaqueCtx.opaque;
252 
253 	if (ctx->strLast != NULL) {
254 		str->prevDone = ctx->strLast;
255 		ctx->strLast->nextDone = str;
256 		ctx->strLast = str;
257 	} else {
258 		INSIST(ctx->strDone == NULL);
259 		ctx->strDone = ctx->strLast = str;
260 	}
261 	evDeselectFD(opaqueCtx, str->file);
262 	str->file.opaque = NULL;
263 	/* evDrop() will call evCancelRW() on us. */
264 }
265 
266 /* Dribble out some bytes on the stream.  (Called by evDispatch().) */
267 static void
268 writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
269 	evStream *str = uap;
270 	int bytes;
271 
272 	UNUSED(evmask);
273 
274 	bytes = writev(fd, str->iovCur, str->iovCurCount);
275 	if (bytes > 0) {
276 		if ((str->flags & EV_STR_TIMEROK) != 0)
277 			evTouchIdleTimer(opaqueCtx, str->timer);
278 		consume(str, bytes);
279 	} else {
280 		if (bytes < 0 && errno != EINTR) {
281 			str->ioDone = -1;
282 			str->ioErrno = errno;
283 		}
284 	}
285 	if (str->ioDone == -1 || str->ioDone == str->ioTotal)
286 		done(opaqueCtx, str);
287 }
288 
289 /* Scoop up some bytes from the stream.  (Called by evDispatch().) */
290 static void
291 readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
292 	evStream *str = uap;
293 	int bytes;
294 
295 	UNUSED(evmask);
296 
297 	bytes = readv(fd, str->iovCur, str->iovCurCount);
298 	if (bytes > 0) {
299 		if ((str->flags & EV_STR_TIMEROK) != 0)
300 			evTouchIdleTimer(opaqueCtx, str->timer);
301 		consume(str, bytes);
302 	} else {
303 		if (bytes == 0)
304 			str->ioDone = 0;
305 		else {
306 			if (errno != EINTR) {
307 				str->ioDone = -1;
308 				str->ioErrno = errno;
309 			}
310 		}
311 	}
312 	if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
313 		done(opaqueCtx, str);
314 }
315 #endif
316 
317 /*! \file */
318