src/kits/network/netresolv/isc/ev_waits.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_waits.c - implement deferred function calls for the eventlib
  19  * vix 05dec95 [initial]
  20  */
  21
  22 #if !defined(LINT) && !defined(CODECENTER)
  23 static const char rcsid[] = "$Id: ev_waits.c,v 1.4 2005/04/27 04:56:36 sra Exp $";
  24 #endif
  25
  26 #include "port_before.h"
  27 #include "fd_setsize.h"
  28
  29 #include <errno.h>
  30
  31 #include <isc/eventlib.h>
  32 #include <isc/assertions.h>
  33 #include "eventlib_p.h"
  34
  35 #include "port_after.h"
  36
  37 /* Forward. */
  38
  39 static void             print_waits(evContext_p *ctx);
  40 static evWaitList *     evNewWaitList(evContext_p *);
  41 static void             evFreeWaitList(evContext_p *, evWaitList *);
  42 static evWaitList *     evGetWaitList(evContext_p *, const void *, int);
  43
  44
  45 /* Public. */
  46
  47 /*%
  48  * Enter a new wait function on the queue.
  49  */
  50 int
  51 evWaitFor(evContext opaqueCtx, const void *tag,
  52           evWaitFunc func, void *uap, evWaitID *id)
  53 {
  54         evContext_p *ctx = opaqueCtx.opaque;
  55         evWait *new;
  56         evWaitList *wl = evGetWaitList(ctx, tag, 1);
  57
  58         OKNEW(new);
  59         new->func = func;
  60         new->uap = uap;
  61         new->tag = tag;
  62         new->next = NULL;
  63         if (wl->last != NULL)
  64                 wl->last->next = new;
  65         else
  66                 wl->first = new;
  67         wl->last = new;
  68         if (id != NULL)
  69                 id->opaque = new;
  70         if (ctx->debug >= 9)
  71                 print_waits(ctx);
  72         return (0);
  73 }
  74
  75 /*%
  76  * Mark runnable all waiting functions having a certain tag.
  77  */
  78 int
  79 evDo(evContext opaqueCtx, const void *tag) {
  80         evContext_p *ctx = opaqueCtx.opaque;
  81         evWaitList *wl = evGetWaitList(ctx, tag, 0);
  82         evWait *first;
  83
  84         if (!wl) {
  85                 errno = ENOENT;
  86                 return (-1);
  87         }
  88
  89         first = wl->first;
  90         INSIST(first != NULL);
  91
  92         if (ctx->waitDone.last != NULL)
  93                 ctx->waitDone.last->next = first;
  94         else
  95                 ctx->waitDone.first = first;
  96         ctx->waitDone.last = wl->last;
  97         evFreeWaitList(ctx, wl);
  98
  99         return (0);
 100 }
 101
 102 /*%
 103  * Remove a waiting (or ready to run) function from the queue.
 104  */
 105 int
 106 evUnwait(evContext opaqueCtx, evWaitID id) {
 107         evContext_p *ctx = opaqueCtx.opaque;
 108         evWait *this, *prev;
 109         evWaitList *wl;
 110         int found = 0;
 111
 112         this = id.opaque;
 113         INSIST(this != NULL);
 114         wl = evGetWaitList(ctx, this->tag, 0);
 115         if (wl != NULL) {
 116                 for (prev = NULL, this = wl->first;
 117                      this != NULL;
 118                      prev = this, this = this->next)
 119                         if (this == (evWait *)id.opaque) {
 120                                 found = 1;
 121                                 if (prev != NULL)
 122                                         prev->next = this->next;
 123                                 else
 124                                         wl->first = this->next;
 125                                 if (wl->last == this)
 126                                         wl->last = prev;
 127                                 if (wl->first == NULL)
 128                                         evFreeWaitList(ctx, wl);
 129                                 break;
 130                         }
 131         }
 132
 133         if (!found) {
 134                 /* Maybe it's done */
 135                 for (prev = NULL, this = ctx->waitDone.first;
 136                      this != NULL;
 137                      prev = this, this = this->next)
 138                         if (this == (evWait *)id.opaque) {
 139                                 found = 1;
 140                                 if (prev != NULL)
 141                                         prev->next = this->next;
 142                                 else
 143                                         ctx->waitDone.first = this->next;
 144                                 if (ctx->waitDone.last == this)
 145                                         ctx->waitDone.last = prev;
 146                                 break;
 147                         }
 148         }
 149
 150         if (!found) {
 151                 errno = ENOENT;
 152                 return (-1);
 153         }
 154
 155         FREE(this);
 156
 157         if (ctx->debug >= 9)
 158                 print_waits(ctx);
 159
 160         return (0);
 161 }
 162
 163 int
 164 evDefer(evContext opaqueCtx, evWaitFunc func, void *uap) {
 165         evContext_p *ctx = opaqueCtx.opaque;
 166         evWait *new;
 167
 168         OKNEW(new);
 169         new->func = func;
 170         new->uap = uap;
 171         new->tag = NULL;
 172         new->next = NULL;
 173         if (ctx->waitDone.last != NULL)
 174                 ctx->waitDone.last->next = new;
 175         else
 176                 ctx->waitDone.first = new;
 177         ctx->waitDone.last = new;
 178         if (ctx->debug >= 9)
 179                 print_waits(ctx);
 180         return (0);
 181 }
 182
 183 /* Private. */
 184
 185 static void
 186 print_waits(evContext_p *ctx) {
 187         evWaitList *wl;
 188         evWait *this;
 189
 190         evPrintf(ctx, 9, "wait waiting:\n");
 191         for (wl = ctx->waitLists; wl != NULL; wl = wl->next) {
 192                 INSIST(wl->first != NULL);
 193                 evPrintf(ctx, 9, "  tag %p:", wl->first->tag);
 194                 for (this = wl->first; this != NULL; this = this->next)
 195                         evPrintf(ctx, 9, " %p", this);
 196                 evPrintf(ctx, 9, "\n");
 197         }
 198         evPrintf(ctx, 9, "wait done:");
 199         for (this = ctx->waitDone.first; this != NULL; this = this->next)
 200                 evPrintf(ctx, 9, " %p", this);
 201         evPrintf(ctx, 9, "\n");
 202 }
 203
 204 static evWaitList *
 205 evNewWaitList(evContext_p *ctx) {
 206         evWaitList *new;
 207
 208         NEW(new);
 209         if (new == NULL)
 210                 return (NULL);
 211         new->first = new->last = NULL;
 212         new->prev = NULL;
 213         new->next = ctx->waitLists;
 214         if (new->next != NULL)
 215                 new->next->prev = new;
 216         ctx->waitLists = new;
 217         return (new);
 218 }
 219
 220 static void
 221 evFreeWaitList(evContext_p *ctx, evWaitList *this) {
 222
 223         INSIST(this != NULL);
 224
 225         if (this->prev != NULL)
 226                 this->prev->next = this->next;
 227         else
 228                 ctx->waitLists = this->next;
 229         if (this->next != NULL)
 230                 this->next->prev = this->prev;
 231         FREE(this);
 232 }
 233
 234 static evWaitList *
 235 evGetWaitList(evContext_p *ctx, const void *tag, int should_create) {
 236         evWaitList *this;
 237
 238         for (this = ctx->waitLists; this != NULL; this = this->next) {
 239                 if (this->first != NULL && this->first->tag == tag)
 240                         break;
 241         }
 242         if (this == NULL && should_create)
 243                 this = evNewWaitList(ctx);
 244         return (this);
 245 }
 246
 247 /*! \file */