xref: /freebsd/lib/libc/isc/ev_streams.c (revision 8c2f6c3be0125142d3c1782e4b0ee0634c584b9e) 
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 #include "port_before.h"
25 #ifndef _LIBC
26 #include "fd_setsize.h"
27 #endif
28 
29 #include <sys/types.h>
30 #include <sys/uio.h>
31 
32 #include <errno.h>
33 
34 #include <isc/eventlib.h>
35 #ifndef _LIBC
36 #include <isc/assertions.h>
37 #endif
38 #include "eventlib_p.h"
39 
40 #include "port_after.h"
41 
42 #ifndef _LIBC
43 static int	copyvec(evStream *str, const struct iovec *iov, int iocnt);
44 static void	consume(evStream *str, size_t bytes);
45 static void	done(evContext opaqueCtx, evStream *str);
46 static void	writable(evContext opaqueCtx, void *uap, int fd, int evmask);
47 static void	readable(evContext opaqueCtx, void *uap, int fd, int evmask);
48 #endif
49 
50 struct iovec
51 evConsIovec(void *buf, size_t cnt) {
52 	struct iovec ret;
53 
54 	memset(&ret, 0xf5, sizeof ret);
55 	ret.iov_base = buf;
56 	ret.iov_len = cnt;
57 	return (ret);
58 }
59 
60 #ifndef _LIBC
61 int
62 evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
63 	evStreamFunc func, void *uap, evStreamID *id)
64 {
65 	evContext_p *ctx = opaqueCtx.opaque;
66 	evStream *new;
67 	int save;
68 
69 	OKNEW(new);
70 	new->func = func;
71 	new->uap = uap;
72 	new->fd = fd;
73 	new->flags = 0;
74 	if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
75 		goto free;
76 	if (copyvec(new, iov, iocnt) < 0)
77 		goto free;
78 	new->prevDone = NULL;
79 	new->nextDone = NULL;
80 	if (ctx->streams != NULL)
81 		ctx->streams->prev = new;
82 	new->prev = NULL;
83 	new->next = ctx->streams;
84 	ctx->streams = new;
85 	if (id != NULL)
86 		id->opaque = new;
87 	return (0);
88  free:
89 	save = errno;
90 	FREE(new);
91 	errno = save;
92 	return (-1);
93 }
94 
95 int
96 evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
97        evStreamFunc func, void *uap, evStreamID *id)
98 {
99 	evContext_p *ctx = opaqueCtx.opaque;
100 	evStream *new;
101 	int save;
102 
103 	OKNEW(new);
104 	new->func = func;
105 	new->uap = uap;
106 	new->fd = fd;
107 	new->flags = 0;
108 	if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
109 		goto free;
110 	if (copyvec(new, iov, iocnt) < 0)
111 		goto free;
112 	new->prevDone = NULL;
113 	new->nextDone = NULL;
114 	if (ctx->streams != NULL)
115 		ctx->streams->prev = new;
116 	new->prev = NULL;
117 	new->next = ctx->streams;
118 	ctx->streams = new;
119 	if (id)
120 		id->opaque = new;
121 	return (0);
122  free:
123 	save = errno;
124 	FREE(new);
125 	errno = save;
126 	return (-1);
127 }
128 
129 int
130 evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
131 	evStream *str = id.opaque;
132 
133 	UNUSED(opaqueCtx);
134 
135 	str->timer = timer;
136 	str->flags |= EV_STR_TIMEROK;
137 	return (0);
138 }
139 
140 int
141 evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
142 	evStream *str = id.opaque;
143 
144 	UNUSED(opaqueCtx);
145 
146 	str->flags &= ~EV_STR_TIMEROK;
147 	return (0);
148 }
149 
150 int
151 evCancelRW(evContext opaqueCtx, evStreamID id) {
152 	evContext_p *ctx = opaqueCtx.opaque;
153 	evStream *old = id.opaque;
154 
155 	/*
156 	 * The streams list is doubly threaded.  First, there's ctx->streams
157 	 * that's used by evDestroy() to find and cancel all streams.  Second,
158 	 * there's ctx->strDone (head) and ctx->strLast (tail) which thread
159 	 * through the potentially smaller number of "IO completed" streams,
160 	 * used in evGetNext() to avoid scanning the entire list.
161 	 */
162 
163 	/* Unlink from ctx->streams. */
164 	if (old->prev != NULL)
165 		old->prev->next = old->next;
166 	else
167 		ctx->streams = old->next;
168 	if (old->next != NULL)
169 		old->next->prev = old->prev;
170 
171 	/*
172 	 * If 'old' is on the ctx->strDone list, remove it.  Update
173 	 * ctx->strLast if necessary.
174 	 */
175 	if (old->prevDone == NULL && old->nextDone == NULL) {
176 		/*
177 		 * Either 'old' is the only item on the done list, or it's
178 		 * not on the done list.  If the former, then we unlink it
179 		 * from the list.  If the latter, we leave the list alone.
180 		 */
181 		if (ctx->strDone == old) {
182 			ctx->strDone = NULL;
183 			ctx->strLast = NULL;
184 		}
185 	} else {
186 		if (old->prevDone != NULL)
187 			old->prevDone->nextDone = old->nextDone;
188 		else
189 			ctx->strDone = old->nextDone;
190 		if (old->nextDone != NULL)
191 			old->nextDone->prevDone = old->prevDone;
192 		else
193 			ctx->strLast = old->prevDone;
194 	}
195 
196 	/* Deallocate the stream. */
197 	if (old->file.opaque)
198 		evDeselectFD(opaqueCtx, old->file);
199 	memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
200 	FREE(old);
201 	return (0);
202 }
203 
204 /* Copy a scatter/gather vector and initialize a stream handler's IO. */
205 static int
206 copyvec(evStream *str, const struct iovec *iov, int iocnt) {
207 	int i;
208 
209 	str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
210 	if (str->iovOrig == NULL) {
211 		errno = ENOMEM;
212 		return (-1);
213 	}
214 	str->ioTotal = 0;
215 	for (i = 0; i < iocnt; i++) {
216 		str->iovOrig[i] = iov[i];
217 		str->ioTotal += iov[i].iov_len;
218 	}
219 	str->iovOrigCount = iocnt;
220 	str->iovCur = str->iovOrig;
221 	str->iovCurCount = str->iovOrigCount;
222 	str->ioDone = 0;
223 	return (0);
224 }
225 
226 /* Pull off or truncate lead iovec(s). */
227 static void
228 consume(evStream *str, size_t bytes) {
229 	while (bytes > 0U) {
230 		if (bytes < (size_t)str->iovCur->iov_len) {
231 			str->iovCur->iov_len -= bytes;
232 			str->iovCur->iov_base = (void *)
233 				((u_char *)str->iovCur->iov_base + bytes);
234 			str->ioDone += bytes;
235 			bytes = 0;
236 		} else {
237 			bytes -= str->iovCur->iov_len;
238 			str->ioDone += str->iovCur->iov_len;
239 			str->iovCur++;
240 			str->iovCurCount--;
241 		}
242 	}
243 }
244 
245 /* Add a stream to Done list and deselect the FD. */
246 static void
247 done(evContext opaqueCtx, evStream *str) {
248 	evContext_p *ctx = opaqueCtx.opaque;
249 
250 	if (ctx->strLast != NULL) {
251 		str->prevDone = ctx->strLast;
252 		ctx->strLast->nextDone = str;
253 		ctx->strLast = str;
254 	} else {
255 		INSIST(ctx->strDone == NULL);
256 		ctx->strDone = ctx->strLast = str;
257 	}
258 	evDeselectFD(opaqueCtx, str->file);
259 	str->file.opaque = NULL;
260 	/* evDrop() will call evCancelRW() on us. */
261 }
262 
263 /* Dribble out some bytes on the stream.  (Called by evDispatch().) */
264 static void
265 writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
266 	evStream *str = uap;
267 	int bytes;
268 
269 	UNUSED(evmask);
270 
271 	bytes = writev(fd, str->iovCur, str->iovCurCount);
272 	if (bytes > 0) {
273 		if ((str->flags & EV_STR_TIMEROK) != 0)
274 			evTouchIdleTimer(opaqueCtx, str->timer);
275 		consume(str, bytes);
276 	} else {
277 		if (bytes < 0 && errno != EINTR) {
278 			str->ioDone = -1;
279 			str->ioErrno = errno;
280 		}
281 	}
282 	if (str->ioDone == -1 || str->ioDone == str->ioTotal)
283 		done(opaqueCtx, str);
284 }
285 
286 /* Scoop up some bytes from the stream.  (Called by evDispatch().) */
287 static void
288 readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
289 	evStream *str = uap;
290 	int bytes;
291 
292 	UNUSED(evmask);
293 
294 	bytes = readv(fd, str->iovCur, str->iovCurCount);
295 	if (bytes > 0) {
296 		if ((str->flags & EV_STR_TIMEROK) != 0)
297 			evTouchIdleTimer(opaqueCtx, str->timer);
298 		consume(str, bytes);
299 	} else {
300 		if (bytes == 0)
301 			str->ioDone = 0;
302 		else {
303 			if (errno != EINTR) {
304 				str->ioDone = -1;
305 				str->ioErrno = errno;
306 			}
307 		}
308 	}
309 	if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
310 		done(opaqueCtx, str);
311 }
312 #endif
313 
314 /*! \file */
315