server/async.c

   1 /*
   2  * Server-side support for async i/o operations
   3  *
   4  * Copyright (C) 1998 Alexandre Julliard
   5  * Copyright (C) 2000 Mike McCormack
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include "config.h"
  23
  24 #include <assert.h>
  25 #include <string.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28 #include <stdio.h>
  29
  30 #include "handle.h"
  31 #include "thread.h"
  32 #include "request.h"
  33
  34 #include "async.h"
  35
  36 void destroy_async( struct async *async )
  37 {
  38     struct async_queue *aq = async->q;
  39
  40     /*fprintf(stderr,"destroyed async %p\n",async->overlapped); */
  41
  42     if(async->timeout)
  43         remove_timeout_user(async->timeout);
  44     async->timeout = NULL;
  45
  46     if(async->prev)
  47         async->prev->next = async->next;
  48     else
  49         aq->head = async->next;
  50
  51     if(async->next)
  52         async->next->prev = async->prev;
  53     else
  54         aq->tail = async->prev;
  55
  56     async->q = NULL;
  57     async->next = NULL;
  58     async->prev = NULL;
  59
  60     free(async);
  61 }
  62
  63 void async_notify(struct async *async, int status)
  64 {
  65     /* fprintf(stderr,"notifying %p!\n",async->overlapped); */
  66     async->status = status;
  67     thread_queue_apc(async->thread, NULL, NULL, APC_ASYNC_IO, 1, 2, async->overlapped, status);
  68 }
  69
  70 void destroy_async_queue( struct async_queue *q )
  71 {
  72     while(q->head)
  73     {
  74         async_notify(q->head, STATUS_CANCELLED);
  75         destroy_async(q->head);
  76     }
  77 }
  78
  79 struct async *find_async(struct async_queue *q, struct thread *thread, void *overlapped)
  80 {
  81     struct async *async;
  82
  83     /* fprintf(stderr,"find_async: %p\n",overlapped); */
  84
  85     if(!q)
  86         return NULL;
  87
  88     for(async = q->head; async; async = async->next)
  89         if((async->overlapped==overlapped) && (async->thread == thread))
  90              return async;
  91
  92     return NULL;
  93 }
  94
  95 void async_insert(struct async_queue *q, struct async *async)
  96 {
  97     async->q = q;
  98     async->prev = q->tail;
  99     async->next = NULL;
 100
 101     if(q->tail)
 102         q->tail->next = async;
 103     else
 104         q->head = async;
 105
 106     q->tail = async;
 107 }
 108
 109 static void async_callback(void *private)
 110 {
 111     struct async *async = (struct async *)private;
 112
 113     /* fprintf(stderr,"%p timeout out\n",async->overlapped); */
 114     async->timeout = NULL;
 115     async_notify(async, STATUS_TIMEOUT);
 116     destroy_async(async);
 117 }
 118
 119 struct async *create_async(struct object *obj, struct thread *thread,
 120                            void *overlapped)
 121 {
 122     struct async *async = (struct async *) malloc(sizeof(struct async));
 123     if(!async)
 124     {
 125         set_error(STATUS_NO_MEMORY);
 126         return NULL;
 127     }
 128
 129     async->obj = obj;
 130     async->thread = thread;
 131     async->overlapped = overlapped;
 132     async->next = NULL;
 133     async->prev = NULL;
 134     async->q = NULL;
 135     async->status = STATUS_PENDING;
 136     async->timeout = NULL;
 137
 138     return async;
 139 }
 140
 141 void async_add_timeout(struct async *async, int timeout)
 142 {
 143     if(timeout)
 144     {
 145         gettimeofday( &async->when, 0 );
 146         add_timeout( &async->when, timeout );
 147         async->timeout = add_timeout_user( &async->when, async_callback, async );
 148     }
 149 }
 150
 151 DECL_HANDLER(register_async)
 152 {
 153     struct object *obj = get_handle_obj( current->process, req->handle, 0, NULL);
 154
 155     if ( !(obj) || !obj->ops->queue_async )
 156     {
 157         set_error(STATUS_INVALID_HANDLE);
 158         return;
 159     }
 160
 161 /*
 162  * The queue_async method must do the following:
 163  *
 164  * 1. Get the async_queue for the request of given type.
 165  * 2. Call find_async() to look for the specific client request in the queue (=> NULL if not found).
 166  * 3. If status is STATUS_PENDING:
 167  *      a) If no async request found in step 2 (new request): call create_async() to initialize one.
 168  *      b) Set request's status to STATUS_PENDING.
 169  *      c) If the "queue" field of the async request is NULL: call async_insert() to put it into the queue.
 170  *    Otherwise:
 171  *      If the async request was found in step 2, destroy it by calling destroy_async().
 172  * 4. Carry out any operations necessary to adjust the object's poll events
 173  *    Usually: set_elect_events (obj, obj->ops->get_poll_events()).
 174  *
 175  * See also the implementations in file.c, serial.c, and sock.c.
 176 */
 177
 178     obj->ops->queue_async (obj, req->overlapped, req->status, req->type, req->count);
 179     release_object(obj);
 180 }
 181