lib/libc/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  * $Id: ev_streams.c,v 1.5 2005/04/27 04:56:36 sra Exp $
  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 /* !_LIBC */
 313
 314 /*! \file */