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_open_file,              /* open_file */
  61     no_close_handle,           /* close_handle */
  62     async_destroy              /* destroy */
  63 };
  64
  65 static void async_dump( struct object *obj, int verbose )
  66 {
  67     struct async *async = (struct async *)obj;
  68     assert( obj->ops == &async_ops );
  69     fprintf( stderr, "Async thread=%p\n", async->thread );
  70 }
  71
  72 static void async_destroy( struct object *obj )
  73 {
  74     struct async *async = (struct async *)obj;
  75     assert( obj->ops == &async_ops );
  76
  77     if (async->timeout) remove_timeout_user( async->timeout );
  78     if (async->event) release_object( async->event );
  79     release_object( async->thread );
  80 }
  81
  82 /* notifies client thread of new status of its async request */
  83 /* destroys the server side of it */
  84 static void async_terminate( struct async *async, unsigned int status )
  85 {
  86     apc_call_t data;
  87
  88     memset( &data, 0, sizeof(data) );
  89     data.type            = APC_ASYNC_IO;
  90     data.async_io.func   = async->data.callback;
  91     data.async_io.user   = async->data.arg;
  92     data.async_io.sb     = async->data.iosb;
  93     data.async_io.status = status;
  94     thread_queue_apc( async->thread, &async->obj, &data );
  95
  96     if (async->timeout) remove_timeout_user( async->timeout );
  97     async->timeout = NULL;
  98     list_remove( &async->queue_entry );
  99     release_object( async );
 100 }
 101
 102 /* callback for timeout on an async request */
 103 static void async_timeout( void *private )
 104 {
 105     struct async *async = private;
 106
 107     async->timeout = NULL;
 108     async_terminate( async, STATUS_TIMEOUT );
 109 }
 110
 111 /* create an async on a given queue of a fd */
 112 struct async *create_async( struct thread *thread, const struct timeval *timeout,
 113                             struct list *queue, const async_data_t *data )
 114 {
 115     struct event *event = NULL;
 116     struct async *async;
 117
 118     if (data->event && !(event = get_event_obj( thread->process, data->event, EVENT_MODIFY_STATE )))
 119         return NULL;
 120
 121     if (!(async = alloc_object( &async_ops )))
 122     {
 123         if (event) release_object( event );
 124         return NULL;
 125     }
 126
 127     async->thread = (struct thread *)grab_object( thread );
 128     async->event = event;
 129     async->data = *data;
 130
 131     list_add_tail( queue, &async->queue_entry );
 132
 133     if (timeout) async->timeout = add_timeout_user( timeout, async_timeout, async );
 134     else async->timeout = NULL;
 135
 136     if (event) reset_event( event );
 137     return async;
 138 }
 139
 140 /* store the result of the client-side async callback */
 141 void async_set_result( struct object *obj, unsigned int status )
 142 {
 143     struct async *async = (struct async *)obj;
 144
 145     if (obj->ops != &async_ops) return;  /* in case the client messed up the APC results */
 146
 147     if (status == STATUS_PENDING)
 148     {
 149         /* FIXME: restart the async operation */
 150     }
 151     else
 152     {
 153         if (async->event) set_event( async->event );
 154     }
 155 }
 156
 157 /* terminate the async operation at the head of the queue */
 158 void async_terminate_head( struct list *queue, unsigned int status )
 159 {
 160     struct list *ptr = list_head( queue );
 161     if (ptr) async_terminate( LIST_ENTRY( ptr, struct async, queue_entry ), status );
 162 }
 163
 164 /* terminate all async operations on the queue */
 165 void async_terminate_queue( struct list *queue, unsigned int status )
 166 {
 167     struct list *ptr, *next;
 168
 169     LIST_FOR_EACH_SAFE( ptr, next, queue )
 170     {
 171         struct async *async = LIST_ENTRY( ptr, struct async, queue_entry );
 172         async_terminate( async, status );
 173     }
 174 }