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 #include "port_before.h"
23 #include "fd_setsize.h"
24 
25 #include <sys/types.h>
26 #include <sys/uio.h>
27 
28 #include <errno.h>
29 
30 #include <isc/eventlib.h>
31 #include <isc/assertions.h>
32 #include "eventlib_p.h"
33 
34 #include "port_after.h"
35 
36 static int	copyvec(evStream *str, const struct iovec *iov, int iocnt);
37 static void	consume(evStream *str, size_t bytes);
38 static void	done(evContext opaqueCtx, evStream *str);
39 static void	writable(evContext opaqueCtx, void *uap, int fd, int evmask);
40 static void	readable(evContext opaqueCtx, void *uap, int fd, int evmask);
41 
42 struct iovec
evConsIovec(void * buf,size_t cnt)43 evConsIovec(void *buf, size_t cnt) {
44 	struct iovec ret;
45 
46 	memset(&ret, 0xf5, sizeof ret);
47 	ret.iov_base = buf;
48 	ret.iov_len = cnt;
49 	return (ret);
50 }
51 
52 int
evWrite(evContext opaqueCtx,int fd,const struct iovec * iov,int iocnt,evStreamFunc func,void * uap,evStreamID * id)53 evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
54 	evStreamFunc func, void *uap, evStreamID *id)
55 {
56 	evContext_p *ctx = opaqueCtx.opaque;
57 	evStream *new;
58 	int save;
59 
60 	OKNEW(new);
61 	new->func = func;
62 	new->uap = uap;
63 	new->fd = fd;
64 	new->flags = 0;
65 	if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
66 		goto free;
67 	if (copyvec(new, iov, iocnt) < 0)
68 		goto free;
69 	new->prevDone = NULL;
70 	new->nextDone = NULL;
71 	if (ctx->streams != NULL)
72 		ctx->streams->prev = new;
73 	new->prev = NULL;
74 	new->next = ctx->streams;
75 	ctx->streams = new;
76 	if (id != NULL)
77 		id->opaque = new;
78 	return (0);
79  free:
80 	save = errno;
81 	FREE(new);
82 	errno = save;
83 	return (-1);
84 }
85 
86 int
evRead(evContext opaqueCtx,int fd,const struct iovec * iov,int iocnt,evStreamFunc func,void * uap,evStreamID * id)87 evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
88        evStreamFunc func, void *uap, evStreamID *id)
89 {
90 	evContext_p *ctx = opaqueCtx.opaque;
91 	evStream *new;
92 	int save;
93 
94 	OKNEW(new);
95 	new->func = func;
96 	new->uap = uap;
97 	new->fd = fd;
98 	new->flags = 0;
99 	if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
100 		goto free;
101 	if (copyvec(new, iov, iocnt) < 0)
102 		goto free;
103 	new->prevDone = NULL;
104 	new->nextDone = NULL;
105 	if (ctx->streams != NULL)
106 		ctx->streams->prev = new;
107 	new->prev = NULL;
108 	new->next = ctx->streams;
109 	ctx->streams = new;
110 	if (id)
111 		id->opaque = new;
112 	return (0);
113  free:
114 	save = errno;
115 	FREE(new);
116 	errno = save;
117 	return (-1);
118 }
119 
120 int
evTimeRW(evContext opaqueCtx,evStreamID id,evTimerID timer)121 evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
122 	evStream *str = id.opaque;
123 
124 	UNUSED(opaqueCtx);
125 
126 	str->timer = timer;
127 	str->flags |= EV_STR_TIMEROK;
128 	return (0);
129 }
130 
131 int
evUntimeRW(evContext opaqueCtx,evStreamID id)132 evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
133 	evStream *str = id.opaque;
134 
135 	UNUSED(opaqueCtx);
136 
137 	str->flags &= ~EV_STR_TIMEROK;
138 	return (0);
139 }
140 
141 int
evCancelRW(evContext opaqueCtx,evStreamID id)142 evCancelRW(evContext opaqueCtx, evStreamID id) {
143 	evContext_p *ctx = opaqueCtx.opaque;
144 	evStream *old = id.opaque;
145 
146 	/*
147 	 * The streams list is doubly threaded.  First, there's ctx->streams
148 	 * that's used by evDestroy() to find and cancel all streams.  Second,
149 	 * there's ctx->strDone (head) and ctx->strLast (tail) which thread
150 	 * through the potentially smaller number of "IO completed" streams,
151 	 * used in evGetNext() to avoid scanning the entire list.
152 	 */
153 
154 	/* Unlink from ctx->streams. */
155 	if (old->prev != NULL)
156 		old->prev->next = old->next;
157 	else
158 		ctx->streams = old->next;
159 	if (old->next != NULL)
160 		old->next->prev = old->prev;
161 
162 	/*
163 	 * If 'old' is on the ctx->strDone list, remove it.  Update
164 	 * ctx->strLast if necessary.
165 	 */
166 	if (old->prevDone == NULL && old->nextDone == NULL) {
167 		/*
168 		 * Either 'old' is the only item on the done list, or it's
169 		 * not on the done list.  If the former, then we unlink it
170 		 * from the list.  If the latter, we leave the list alone.
171 		 */
172 		if (ctx->strDone == old) {
173 			ctx->strDone = NULL;
174 			ctx->strLast = NULL;
175 		}
176 	} else {
177 		if (old->prevDone != NULL)
178 			old->prevDone->nextDone = old->nextDone;
179 		else
180 			ctx->strDone = old->nextDone;
181 		if (old->nextDone != NULL)
182 			old->nextDone->prevDone = old->prevDone;
183 		else
184 			ctx->strLast = old->prevDone;
185 	}
186 
187 	/* Deallocate the stream. */
188 	if (old->file.opaque)
189 		evDeselectFD(opaqueCtx, old->file);
190 	memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
191 	FREE(old);
192 	return (0);
193 }
194 
195 /* Copy a scatter/gather vector and initialize a stream handler's IO. */
196 static int
copyvec(evStream * str,const struct iovec * iov,int iocnt)197 copyvec(evStream *str, const struct iovec *iov, int iocnt) {
198 	int i;
199 
200 	str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
201 	if (str->iovOrig == NULL) {
202 		errno = ENOMEM;
203 		return (-1);
204 	}
205 	str->ioTotal = 0;
206 	for (i = 0; i < iocnt; i++) {
207 		str->iovOrig[i] = iov[i];
208 		str->ioTotal += iov[i].iov_len;
209 	}
210 	str->iovOrigCount = iocnt;
211 	str->iovCur = str->iovOrig;
212 	str->iovCurCount = str->iovOrigCount;
213 	str->ioDone = 0;
214 	return (0);
215 }
216 
217 /* Pull off or truncate lead iovec(s). */
218 static void
consume(evStream * str,size_t bytes)219 consume(evStream *str, size_t bytes) {
220 	while (bytes > 0U) {
221 		if (bytes < (size_t)str->iovCur->iov_len) {
222 			str->iovCur->iov_len -= bytes;
223 			str->iovCur->iov_base = (void *)
224 				((u_char *)str->iovCur->iov_base + bytes);
225 			str->ioDone += bytes;
226 			bytes = 0;
227 		} else {
228 			bytes -= str->iovCur->iov_len;
229 			str->ioDone += str->iovCur->iov_len;
230 			str->iovCur++;
231 			str->iovCurCount--;
232 		}
233 	}
234 }
235 
236 /* Add a stream to Done list and deselect the FD. */
237 static void
done(evContext opaqueCtx,evStream * str)238 done(evContext opaqueCtx, evStream *str) {
239 	evContext_p *ctx = opaqueCtx.opaque;
240 
241 	if (ctx->strLast != NULL) {
242 		str->prevDone = ctx->strLast;
243 		ctx->strLast->nextDone = str;
244 		ctx->strLast = str;
245 	} else {
246 		INSIST(ctx->strDone == NULL);
247 		ctx->strDone = ctx->strLast = str;
248 	}
249 	evDeselectFD(opaqueCtx, str->file);
250 	str->file.opaque = NULL;
251 	/* evDrop() will call evCancelRW() on us. */
252 }
253 
254 /* Dribble out some bytes on the stream.  (Called by evDispatch().) */
255 static void
writable(evContext opaqueCtx,void * uap,int fd,int evmask)256 writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
257 	evStream *str = uap;
258 	int bytes;
259 
260 	UNUSED(evmask);
261 
262 	bytes = writev(fd, str->iovCur, str->iovCurCount);
263 	if (bytes > 0) {
264 		if ((str->flags & EV_STR_TIMEROK) != 0)
265 			evTouchIdleTimer(opaqueCtx, str->timer);
266 		consume(str, bytes);
267 	} else {
268 		if (bytes < 0 && errno != EINTR) {
269 			str->ioDone = -1;
270 			str->ioErrno = errno;
271 		}
272 	}
273 	if (str->ioDone == -1 || str->ioDone == str->ioTotal)
274 		done(opaqueCtx, str);
275 }
276 
277 /* Scoop up some bytes from the stream.  (Called by evDispatch().) */
278 static void
readable(evContext opaqueCtx,void * uap,int fd,int evmask)279 readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
280 	evStream *str = uap;
281 	int bytes;
282 
283 	UNUSED(evmask);
284 
285 	bytes = readv(fd, str->iovCur, str->iovCurCount);
286 	if (bytes > 0) {
287 		if ((str->flags & EV_STR_TIMEROK) != 0)
288 			evTouchIdleTimer(opaqueCtx, str->timer);
289 		consume(str, bytes);
290 	} else {
291 		if (bytes == 0)
292 			str->ioDone = 0;
293 		else {
294 			if (errno != EINTR) {
295 				str->ioDone = -1;
296 				str->ioErrno = errno;
297 			}
298 		}
299 	}
300 	if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
301 		done(opaqueCtx, str);
302 }
303 
304 /*! \file */
305