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 async queue list */
  40     struct async_queue  *queue;           /* queue containing this async */
  41     unsigned int         status;          /* current status */
  42     struct timeout_user *timeout;
  43     unsigned int         timeout_status;  /* status to report upon timeout */
  44     struct event        *event;
  45     async_data_t         data;            /* data for async I/O call */
  46 };
  47
  48 static void async_dump( struct object *obj, int verbose );
  49 static void async_destroy( struct object *obj );
  50
  51 static const struct object_ops async_ops =
  52 {
  53     sizeof(struct async),      /* size */
  54     async_dump,                /* dump */
  55     no_add_queue,              /* add_queue */
  56     NULL,                      /* remove_queue */
  57     NULL,                      /* signaled */
  58     NULL,                      /* satisfied */
  59     no_signal,                 /* signal */
  60     no_get_fd,                 /* get_fd */
  61     no_map_access,             /* map_access */
  62     no_lookup_name,            /* lookup_name */
  63     no_open_file,              /* open_file */
  64     no_close_handle,           /* close_handle */
  65     async_destroy              /* destroy */
  66 };
  67
  68
  69 struct async_queue
  70 {
  71     struct object        obj;             /* object header */
  72     struct fd           *fd;              /* file descriptor owning this queue */
  73     struct list          queue;           /* queue of async objects */
  74 };
  75
  76 static void async_queue_dump( struct object *obj, int verbose );
  77
  78 static const struct object_ops async_queue_ops =
  79 {
  80     sizeof(struct async_queue),      /* size */
  81     async_queue_dump,                /* dump */
  82     no_add_queue,                    /* add_queue */
  83     NULL,                            /* remove_queue */
  84     NULL,                            /* signaled */
  85     NULL,                            /* satisfied */
  86     no_signal,                       /* signal */
  87     no_get_fd,                       /* get_fd */
  88     no_map_access,                   /* map_access */
  89     no_lookup_name,                  /* lookup_name */
  90     no_open_file,                    /* open_file */
  91     no_close_handle,                 /* close_handle */
  92     no_destroy                       /* destroy */
  93 };
  94
  95
  96 static inline void async_reselect( struct async *async )
  97 {
  98     if (async->queue->fd) fd_reselect_async( async->queue->fd, async->queue );
  99 }
 100
 101 static void async_dump( struct object *obj, int verbose )
 102 {
 103     struct async *async = (struct async *)obj;
 104     assert( obj->ops == &async_ops );
 105     fprintf( stderr, "Async thread=%p\n", async->thread );
 106 }
 107
 108 static void async_destroy( struct object *obj )
 109 {
 110     struct async *async = (struct async *)obj;
 111     assert( obj->ops == &async_ops );
 112
 113     list_remove( &async->queue_entry );
 114     async_reselect( async );
 115
 116     if (async->timeout) remove_timeout_user( async->timeout );
 117     if (async->event) release_object( async->event );
 118     release_object( async->queue );
 119     release_object( async->thread );
 120 }
 121
 122 static void async_queue_dump( struct object *obj, int verbose )
 123 {
 124     struct async_queue *async_queue = (struct async_queue *)obj;
 125     assert( obj->ops == &async_queue_ops );
 126     fprintf( stderr, "Async queue fd=%p\n", async_queue->fd );
 127 }
 128
 129 /* notifies client thread of new status of its async request */
 130 static void async_terminate( struct async *async, unsigned int status )
 131 {
 132     apc_call_t data;
 133
 134     assert( status != STATUS_PENDING );
 135
 136     if (async->status != STATUS_PENDING)
 137     {
 138         /* already terminated, just update status */
 139         async->status = status;
 140         return;
 141     }
 142
 143     memset( &data, 0, sizeof(data) );
 144     data.type            = APC_ASYNC_IO;
 145     data.async_io.func   = async->data.callback;
 146     data.async_io.user   = async->data.arg;
 147     data.async_io.sb     = async->data.iosb;
 148     data.async_io.status = status;
 149     thread_queue_apc( async->thread, &async->obj, &data );
 150     async->status = status;
 151     async_reselect( async );
 152     release_object( async );  /* so that it gets destroyed when the async is done */
 153 }
 154
 155 /* callback for timeout on an async request */
 156 static void async_timeout( void *private )
 157 {
 158     struct async *async = private;
 159
 160     async->timeout = NULL;
 161     async_terminate( async, async->timeout_status );
 162 }
 163
 164 /* create a new async queue for a given fd */
 165 struct async_queue *create_async_queue( struct fd *fd )
 166 {
 167     struct async_queue *queue = alloc_object( &async_queue_ops );
 168
 169     if (queue)
 170     {
 171         queue->fd = fd;
 172         list_init( &queue->queue );
 173     }
 174     return queue;
 175 }
 176
 177 /* free an async queue, cancelling all async operations */
 178 void free_async_queue( struct async_queue *queue )
 179 {
 180     if (!queue) return;
 181     queue->fd = NULL;
 182     async_wake_up( queue, STATUS_HANDLES_CLOSED );
 183     release_object( queue );
 184 }
 185
 186 /* create an async on a given queue of a fd */
 187 struct async *create_async( struct thread *thread, struct async_queue *queue, const async_data_t *data )
 188 {
 189     struct event *event = NULL;
 190     struct async *async;
 191
 192     if (data->event && !(event = get_event_obj( thread->process, data->event, EVENT_MODIFY_STATE )))
 193         return NULL;
 194
 195     if (!(async = alloc_object( &async_ops )))
 196     {
 197         if (event) release_object( event );
 198         return NULL;
 199     }
 200
 201     async->thread  = (struct thread *)grab_object( thread );
 202     async->event   = event;
 203     async->status  = STATUS_PENDING;
 204     async->data    = *data;
 205     async->timeout = NULL;
 206     async->queue   = (struct async_queue *)grab_object( queue );
 207
 208     list_add_tail( &queue->queue, &async->queue_entry );
 209     grab_object( async );
 210
 211     if (queue->fd) set_fd_signaled( queue->fd, 0 );
 212     if (event) reset_event( event );
 213     return async;
 214 }
 215
 216 /* set the timeout of an async operation */
 217 void async_set_timeout( struct async *async, const struct timeval *timeout, unsigned int status )
 218 {
 219     if (async->timeout) remove_timeout_user( async->timeout );
 220     if (timeout) async->timeout = add_timeout_user( timeout, async_timeout, async );
 221     else async->timeout = NULL;
 222     async->timeout_status = status;
 223 }
 224
 225 /* store the result of the client-side async callback */
 226 void async_set_result( struct object *obj, unsigned int status )
 227 {
 228     struct async *async = (struct async *)obj;
 229
 230     if (obj->ops != &async_ops) return;  /* in case the client messed up the APC results */
 231
 232     assert( async->status != STATUS_PENDING );  /* it must have been woken up if we get a result */
 233
 234     if (status == STATUS_PENDING)  /* restart it */
 235     {
 236         status = async->status;
 237         async->status = STATUS_PENDING;
 238         grab_object( async );
 239
 240         if (status != STATUS_ALERTED)  /* it was terminated in the meantime */
 241             async_terminate( async, status );
 242         else
 243             async_reselect( async );
 244     }
 245     else
 246     {
 247         if (async->timeout) remove_timeout_user( async->timeout );
 248         async->timeout = NULL;
 249         async->status = status;
 250         if (async->data.apc)
 251         {
 252             apc_call_t data;
 253             data.type         = APC_USER;
 254             data.user.func    = async->data.apc;
 255             data.user.args[0] = (unsigned long)async->data.apc_arg;
 256             data.user.args[1] = (unsigned long)async->data.iosb;
 257             data.user.args[2] = 0;
 258             thread_queue_apc( async->thread, NULL, &data );
 259         }
 260         if (async->event) set_event( async->event );
 261         else if (async->queue->fd) set_fd_signaled( async->queue->fd, 1 );
 262     }
 263 }
 264
 265 /* check if an async operation is waiting to be alerted */
 266 int async_waiting( struct async_queue *queue )
 267 {
 268     struct list *ptr;
 269     struct async *async;
 270
 271     if (!queue) return 0;
 272     if (!(ptr = list_head( &queue->queue ))) return 0;
 273     async = LIST_ENTRY( ptr, struct async, queue_entry );
 274     return async->status == STATUS_PENDING;
 275 }
 276
 277 /* wake up async operations on the queue */
 278 void async_wake_up( struct async_queue *queue, unsigned int status )
 279 {
 280     struct list *ptr, *next;
 281
 282     if (!queue) return;
 283
 284     LIST_FOR_EACH_SAFE( ptr, next, &queue->queue )
 285     {
 286         struct async *async = LIST_ENTRY( ptr, struct async, queue_entry );
 287         async_terminate( async, status );
 288         if (status == STATUS_ALERTED) break;  /* only wake up the first one */
 289     }
 290 }