external/bsd/libbind/dist/isc/ev_streams.c

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