server/async.c

   1 /*
   2  * Server-side async I/O support
   3  *
   4  * Copyright (C) 2007 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include <assert.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <stdarg.h>
  25
  26 #include "ntstatus.h"
  27 #define WIN32_NO_STATUS
  28 #include "windef.h"
  29 #include "winternl.h"
  30
  31 #include "object.h"
  32 #include "file.h"
  33 #include "request.h"
  34
  35 struct async
  36 {
  37     struct object        obj;             /* object header */
  38     struct thread       *thread;          /* owning thread */
  39     struct list          queue_entry;     /* entry in file descriptor queue */
  40     struct timeout_user *timeout;
  41     struct event        *event;
  42     async_data_t         data;            /* data for async I/O call */
  43 };
  44
  45 static void async_dump( struct object *obj, int verbose );
  46 static void async_destroy( struct object *obj );
  47
  48 static const struct object_ops async_ops =
  49 {
  50     sizeof(struct async),      /* size */
  51     async_dump,                /* dump */
  52     no_add_queue,              /* add_queue */
  53     NULL,                      /* remove_queue */
  54     NULL,                      /* signaled */
  55     NULL,                      /* satisfied */
  56     no_signal,                 /* signal */
  57     no_get_fd,                 /* get_fd */
  58     no_map_access,             /* map_access */
  59     no_lookup_name,            /* lookup_name */
  60     no_close_handle,           /* close_handle */
  61     async_destroy              /* destroy */
  62 };
  63
  64 static void async_dump( struct object *obj, int verbose )
  65 {
  66     struct async *async = (struct async *)obj;
  67     assert( obj->ops == &async_ops );
  68     fprintf( stderr, "Async thread=%p\n", async->thread );
  69 }
  70
  71 static void async_destroy( struct object *obj )
  72 {
  73     struct async *async = (struct async *)obj;
  74     assert( obj->ops == &async_ops );
  75
  76     if (async->timeout) remove_timeout_user( async->timeout );
  77     if (async->event) release_object( async->event );
  78     release_object( async->thread );
  79 }
  80
  81 /* notifies client thread of new status of its async request */
  82 /* destroys the server side of it */
  83 static void async_terminate( struct async *async, unsigned int status )
  84 {
  85     apc_call_t data;
  86
  87     memset( &data, 0, sizeof(data) );
  88     data.type            = APC_ASYNC_IO;
  89     data.async_io.func   = async->data.callback;
  90     data.async_io.user   = async->data.arg;
  91     data.async_io.sb     = async->data.iosb;
  92     data.async_io.status = status;
  93     thread_queue_apc( async->thread, &async->obj, &data );
  94
  95     if (async->timeout) remove_timeout_user( async->timeout );
  96     async->timeout = NULL;
  97     list_remove( &async->queue_entry );
  98     release_object( async );
  99 }
 100
 101 /* callback for timeout on an async request */
 102 static void async_timeout( void *private )
 103 {
 104     struct async *async = private;
 105
 106     async->timeout = NULL;
 107     async_terminate( async, STATUS_TIMEOUT );
 108 }
 109
 110 /* create an async on a given queue of a fd */
 111 struct async *create_async( struct thread *thread, const struct timeval *timeout,
 112                             struct list *queue, const async_data_t *data )
 113 {
 114     struct event *event = NULL;
 115     struct async *async;
 116
 117     if (data->event && !(event = get_event_obj( thread->process, data->event, EVENT_MODIFY_STATE )))
 118         return NULL;
 119
 120     if (!(async = alloc_object( &async_ops )))
 121     {
 122         if (event) release_object( event );
 123         return NULL;
 124     }
 125
 126     async->thread = (struct thread *)grab_object( thread );
 127     async->event = event;
 128     async->data = *data;
 129
 130     list_add_tail( queue, &async->queue_entry );
 131
 132     if (timeout) async->timeout = add_timeout_user( timeout, async_timeout, async );
 133     else async->timeout = NULL;
 134
 135     if (event) reset_event( event );
 136     return async;
 137 }
 138
 139 /* store the result of the client-side async callback */
 140 void async_set_result( struct object *obj, unsigned int status )
 141 {
 142     struct async *async = (struct async *)obj;
 143
 144     if (obj->ops != &async_ops) return;  /* in case the client messed up the APC results */
 145
 146     if (status == STATUS_PENDING)
 147     {
 148         /* FIXME: restart the async operation */
 149     }
 150     else
 151     {
 152         if (async->event) set_event( async->event );
 153     }
 154 }
 155
 156 /* terminate the async operation at the head of the queue */
 157 void async_terminate_head( struct list *queue, unsigned int status )
 158 {
 159     struct list *ptr = list_head( queue );
 160     if (ptr) async_terminate( LIST_ENTRY( ptr, struct async, queue_entry ), status );
 161 }
 162
 163 /* terminate all async operations on the queue */
 164 void async_terminate_queue( struct list *queue, unsigned int status )
 165 {
 166     struct list *ptr, *next;
 167
 168     LIST_FOR_EACH_SAFE( ptr, next, queue )
 169     {
 170         struct async *async = LIST_ENTRY( ptr, struct async, queue_entry );
 171         async_terminate( async, status );
 172     }
 173 }