src/kits/network/netresolv/isc/ev_streams.c

   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 #if !defined(LINT) && !defined(CODECENTER)
  23 static const char rcsid[] = "$Id: ev_streams.c,v 1.5 2005/04/27 04:56:36 sra Exp $";
  24 #endif
  25
  26 #include "port_before.h"
  27 #include "fd_setsize.h"
  28
  29 #include <sys/types.h>
  30 #include <sys/uio.h>
  31
  32 #include <errno.h>
  33
  34 #include <isc/eventlib.h>
  35 #include <isc/assertions.h>
  36 #include "eventlib_p.h"
  37
  38 #include "port_after.h"
  39
  40 static int      copyvec(evStream *str, const struct iovec *iov, int iocnt);
  41 static void     consume(evStream *str, size_t bytes);
  42 static void     done(evContext opaqueCtx, evStream *str);
  43 static void     writable(evContext opaqueCtx, void *uap, int fd, int evmask);
  44 static void     readable(evContext opaqueCtx, void *uap, int fd, int evmask);
  45
  46 struct iovec
  47 evConsIovec(void *buf, size_t cnt) {
  48         struct iovec ret;
  49
  50         memset(&ret, 0xf5, sizeof ret);
  51         ret.iov_base = buf;
  52         ret.iov_len = cnt;
  53         return (ret);
  54 }
  55
  56 int
  57 evWrite(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
  58         evStreamFunc func, void *uap, evStreamID *id)
  59 {
  60         evContext_p *ctx = opaqueCtx.opaque;
  61         evStream *new;
  62         int save;
  63
  64         OKNEW(new);
  65         new->func = func;
  66         new->uap = uap;
  67         new->fd = fd;
  68         new->flags = 0;
  69         if (evSelectFD(opaqueCtx, fd, EV_WRITE, writable, new, &new->file) < 0)
  70                 goto free;
  71         if (copyvec(new, iov, iocnt) < 0)
  72                 goto free;
  73         new->prevDone = NULL;
  74         new->nextDone = NULL;
  75         if (ctx->streams != NULL)
  76                 ctx->streams->prev = new;
  77         new->prev = NULL;
  78         new->next = ctx->streams;
  79         ctx->streams = new;
  80         if (id != NULL)
  81                 id->opaque = new;
  82         return (0);
  83  free:
  84         save = errno;
  85         FREE(new);
  86         errno = save;
  87         return (-1);
  88 }
  89
  90 int
  91 evRead(evContext opaqueCtx, int fd, const struct iovec *iov, int iocnt,
  92        evStreamFunc func, void *uap, evStreamID *id)
  93 {
  94         evContext_p *ctx = opaqueCtx.opaque;
  95         evStream *new;
  96         int save;
  97
  98         OKNEW(new);
  99         new->func = func;
 100         new->uap = uap;
 101         new->fd = fd;
 102         new->flags = 0;
 103         if (evSelectFD(opaqueCtx, fd, EV_READ, readable, new, &new->file) < 0)
 104                 goto free;
 105         if (copyvec(new, iov, iocnt) < 0)
 106                 goto free;
 107         new->prevDone = NULL;
 108         new->nextDone = NULL;
 109         if (ctx->streams != NULL)
 110                 ctx->streams->prev = new;
 111         new->prev = NULL;
 112         new->next = ctx->streams;
 113         ctx->streams = new;
 114         if (id)
 115                 id->opaque = new;
 116         return (0);
 117  free:
 118         save = errno;
 119         FREE(new);
 120         errno = save;
 121         return (-1);
 122 }
 123
 124 int
 125 evTimeRW(evContext opaqueCtx, evStreamID id, evTimerID timer) /*ARGSUSED*/ {
 126         evStream *str = id.opaque;
 127
 128         UNUSED(opaqueCtx);
 129
 130         str->timer = timer;
 131         str->flags |= EV_STR_TIMEROK;
 132         return (0);
 133 }
 134
 135 int
 136 evUntimeRW(evContext opaqueCtx, evStreamID id) /*ARGSUSED*/ {
 137         evStream *str = id.opaque;
 138
 139         UNUSED(opaqueCtx);
 140
 141         str->flags &= ~EV_STR_TIMEROK;
 142         return (0);
 143 }
 144
 145 int
 146 evCancelRW(evContext opaqueCtx, evStreamID id) {
 147         evContext_p *ctx = opaqueCtx.opaque;
 148         evStream *old = id.opaque;
 149
 150         /*
 151          * The streams list is doubly threaded.  First, there's ctx->streams
 152          * that's used by evDestroy() to find and cancel all streams.  Second,
 153          * there's ctx->strDone (head) and ctx->strLast (tail) which thread
 154          * through the potentially smaller number of "IO completed" streams,
 155          * used in evGetNext() to avoid scanning the entire list.
 156          */
 157
 158         /* Unlink from ctx->streams. */
 159         if (old->prev != NULL)
 160                 old->prev->next = old->next;
 161         else
 162                 ctx->streams = old->next;
 163         if (old->next != NULL)
 164                 old->next->prev = old->prev;
 165
 166         /*
 167          * If 'old' is on the ctx->strDone list, remove it.  Update
 168          * ctx->strLast if necessary.
 169          */
 170         if (old->prevDone == NULL && old->nextDone == NULL) {
 171                 /*
 172                  * Either 'old' is the only item on the done list, or it's
 173                  * not on the done list.  If the former, then we unlink it
 174                  * from the list.  If the latter, we leave the list alone.
 175                  */
 176                 if (ctx->strDone == old) {
 177                         ctx->strDone = NULL;
 178                         ctx->strLast = NULL;
 179                 }
 180         } else {
 181                 if (old->prevDone != NULL)
 182                         old->prevDone->nextDone = old->nextDone;
 183                 else
 184                         ctx->strDone = old->nextDone;
 185                 if (old->nextDone != NULL)
 186                         old->nextDone->prevDone = old->prevDone;
 187                 else
 188                         ctx->strLast = old->prevDone;
 189         }
 190
 191         /* Deallocate the stream. */
 192         if (old->file.opaque)
 193                 evDeselectFD(opaqueCtx, old->file);
 194         memput(old->iovOrig, sizeof (struct iovec) * old->iovOrigCount);
 195         FREE(old);
 196         return (0);
 197 }
 198
 199 /* Copy a scatter/gather vector and initialize a stream handler's IO. */
 200 static int
 201 copyvec(evStream *str, const struct iovec *iov, int iocnt) {
 202         int i;
 203
 204         str->iovOrig = (struct iovec *)memget(sizeof(struct iovec) * iocnt);
 205         if (str->iovOrig == NULL) {
 206                 errno = ENOMEM;
 207                 return (-1);
 208         }
 209         str->ioTotal = 0;
 210         for (i = 0; i < iocnt; i++) {
 211                 str->iovOrig[i] = iov[i];
 212                 str->ioTotal += iov[i].iov_len;
 213         }
 214         str->iovOrigCount = iocnt;
 215         str->iovCur = str->iovOrig;
 216         str->iovCurCount = str->iovOrigCount;
 217         str->ioDone = 0;
 218         return (0);
 219 }
 220
 221 /* Pull off or truncate lead iovec(s). */
 222 static void
 223 consume(evStream *str, size_t bytes) {
 224         while (bytes > 0U) {
 225                 if (bytes < (size_t)str->iovCur->iov_len) {
 226                         str->iovCur->iov_len -= bytes;
 227                         str->iovCur->iov_base = (void *)
 228                                 ((u_char *)str->iovCur->iov_base + bytes);
 229                         str->ioDone += bytes;
 230                         bytes = 0;
 231                 } else {
 232                         bytes -= str->iovCur->iov_len;
 233                         str->ioDone += str->iovCur->iov_len;
 234                         str->iovCur++;
 235                         str->iovCurCount--;
 236                 }
 237         }
 238 }
 239
 240 /* Add a stream to Done list and deselect the FD. */
 241 static void
 242 done(evContext opaqueCtx, evStream *str) {
 243         evContext_p *ctx = opaqueCtx.opaque;
 244
 245         if (ctx->strLast != NULL) {
 246                 str->prevDone = ctx->strLast;
 247                 ctx->strLast->nextDone = str;
 248                 ctx->strLast = str;
 249         } else {
 250                 INSIST(ctx->strDone == NULL);
 251                 ctx->strDone = ctx->strLast = str;
 252         }
 253         evDeselectFD(opaqueCtx, str->file);
 254         str->file.opaque = NULL;
 255         /* evDrop() will call evCancelRW() on us. */
 256 }
 257
 258 /* Dribble out some bytes on the stream.  (Called by evDispatch().) */
 259 static void
 260 writable(evContext opaqueCtx, void *uap, int fd, int evmask) {
 261         evStream *str = uap;
 262         int bytes;
 263
 264         UNUSED(evmask);
 265
 266         bytes = writev(fd, str->iovCur, str->iovCurCount);
 267         if (bytes > 0) {
 268                 if ((str->flags & EV_STR_TIMEROK) != 0)
 269                         evTouchIdleTimer(opaqueCtx, str->timer);
 270                 consume(str, bytes);
 271         } else {
 272                 if (bytes < 0 && errno != EINTR) {
 273                         str->ioDone = -1;
 274                         str->ioErrno = errno;
 275                 }
 276         }
 277         if (str->ioDone == -1 || str->ioDone == str->ioTotal)
 278                 done(opaqueCtx, str);
 279 }
 280
 281 /* Scoop up some bytes from the stream.  (Called by evDispatch().) */
 282 static void
 283 readable(evContext opaqueCtx, void *uap, int fd, int evmask) {
 284         evStream *str = uap;
 285         int bytes;
 286
 287         UNUSED(evmask);
 288
 289         bytes = readv(fd, str->iovCur, str->iovCurCount);
 290         if (bytes > 0) {
 291                 if ((str->flags & EV_STR_TIMEROK) != 0)
 292                         evTouchIdleTimer(opaqueCtx, str->timer);
 293                 consume(str, bytes);
 294         } else {
 295                 if (bytes == 0)
 296                         str->ioDone = 0;
 297                 else {
 298                         if (errno != EINTR) {
 299                                 str->ioDone = -1;
 300                                 str->ioErrno = errno;
 301                         }
 302                 }
 303         }
 304         if (str->ioDone <= 0 || str->ioDone == str->ioTotal)
 305                 done(opaqueCtx, str);
 306 }
 307
 308 /*! \file */