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     void                *apc;             /* apc function to call when alerted */
  42     void                *user;            /* user-private argument for apc */
  43     void                *sb;              /* pointer to I/O status block in client addr space */
  44 };
  45
  46 static void async_dump( struct object *obj, int verbose );
  47 static void async_destroy( struct object *obj );
  48
  49 static const struct object_ops async_ops =
  50 {
  51     sizeof(struct async),      /* size */
  52     async_dump,                /* dump */
  53     no_add_queue,              /* add_queue */
  54     NULL,                      /* remove_queue */
  55     NULL,                      /* signaled */
  56     NULL,                      /* satisfied */
  57     no_signal,                 /* signal */
  58     no_get_fd,                 /* get_fd */
  59     no_map_access,             /* map_access */
  60     no_lookup_name,            /* lookup_name */
  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     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->apc;
  90     data.async_io.user   = async->user;
  91     data.async_io.sb     = async->sb;
  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, void *io_apc, void *io_user, void *io_sb )
 113 {
 114     struct async *async = alloc_object( &async_ops );
 115
 116     if (!async) return NULL;
 117
 118     async->thread = (struct thread *)grab_object( thread );
 119     async->apc = io_apc;
 120     async->user = io_user;
 121     async->sb = io_sb;
 122
 123     list_add_tail( queue, &async->queue_entry );
 124
 125     if (timeout) async->timeout = add_timeout_user( timeout, async_timeout, async );
 126     else async->timeout = NULL;
 127
 128     return async;
 129 }
 130
 131 /* terminate the async operation at the head of the queue */
 132 void async_terminate_head( struct list *queue, unsigned int status )
 133 {
 134     struct list *ptr = list_head( queue );
 135     if (ptr) async_terminate( LIST_ENTRY( ptr, struct async, queue_entry ), status );
 136 }
 137
 138 /* terminate all async operations on the queue */
 139 void async_terminate_queue( struct list *queue, unsigned int status )
 140 {
 141     struct list *ptr, *next;
 142
 143     LIST_FOR_EACH_SAFE( ptr, next, queue )
 144     {
 145         struct async *async = LIST_ENTRY( ptr, struct async, queue_entry );
 146         async_terminate( async, status );
 147     }
 148 }