lib/libc/isc/ev_streams.c

   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 */