server/mutex.c

   1 /*
   2  * Server-side mutex management
   3  *
   4  * Copyright (C) 1998 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "config.h"
  22 #include "wine/port.h"
  23
  24 #include <assert.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27
  28 #include "windef.h"
  29 #include "winternl.h"
  30
  31 #include "handle.h"
  32 #include "thread.h"
  33 #include "request.h"
  34
  35 struct mutex
  36 {
  37     struct object  obj;             /* object header */
  38     struct thread *owner;           /* mutex owner */
  39     unsigned int   count;           /* recursion count */
  40     int            abandoned;       /* has it been abandoned? */
  41     struct list    entry;           /* entry in owner thread mutex list */
  42 };
  43
  44 static void mutex_dump( struct object *obj, int verbose );
  45 static int mutex_signaled( struct object *obj, struct thread *thread );
  46 static int mutex_satisfied( struct object *obj, struct thread *thread );
  47 static void mutex_destroy( struct object *obj );
  48 static int mutex_signal( struct object *obj, unsigned int access );
  49
  50 static const struct object_ops mutex_ops =
  51 {
  52     sizeof(struct mutex),      /* size */
  53     mutex_dump,                /* dump */
  54     add_queue,                 /* add_queue */
  55     remove_queue,              /* remove_queue */
  56     mutex_signaled,            /* signaled */
  57     mutex_satisfied,           /* satisfied */
  58     mutex_signal,              /* signal */
  59     no_get_fd,                 /* get_fd */
  60     no_close_handle,           /* close_handle */
  61     mutex_destroy              /* destroy */
  62 };
  63
  64
  65 static struct mutex *create_mutex( const WCHAR *name, size_t len, int owned )
  66 {
  67     struct mutex *mutex;
  68
  69     if ((mutex = create_named_object( sync_namespace, &mutex_ops, name, len )))
  70     {
  71         if (get_error() != STATUS_OBJECT_NAME_COLLISION)
  72         {
  73             /* initialize it if it didn't already exist */
  74             mutex->count = 0;
  75             mutex->owner = NULL;
  76             mutex->abandoned = 0;
  77             if (owned) mutex_satisfied( &mutex->obj, current );
  78         }
  79     }
  80     return mutex;
  81 }
  82
  83 /* release a mutex once the recursion count is 0 */
  84 static void do_release( struct mutex *mutex )
  85 {
  86     assert( !mutex->count );
  87     /* remove the mutex from the thread list of owned mutexes */
  88     list_remove( &mutex->entry );
  89     mutex->owner = NULL;
  90     wake_up( &mutex->obj, 0 );
  91 }
  92
  93 void abandon_mutexes( struct thread *thread )
  94 {
  95     struct list *ptr;
  96
  97     while ((ptr = list_head( &thread->mutex_list )) != NULL)
  98     {
  99         struct mutex *mutex = LIST_ENTRY( ptr, struct mutex, entry );
 100         assert( mutex->owner == thread );
 101         mutex->count = 0;
 102         mutex->abandoned = 1;
 103         do_release( mutex );
 104     }
 105 }
 106
 107 static void mutex_dump( struct object *obj, int verbose )
 108 {
 109     struct mutex *mutex = (struct mutex *)obj;
 110     assert( obj->ops == &mutex_ops );
 111     fprintf( stderr, "Mutex count=%u owner=%p ", mutex->count, mutex->owner );
 112     dump_object_name( &mutex->obj );
 113     fputc( '\n', stderr );
 114 }
 115
 116 static int mutex_signaled( struct object *obj, struct thread *thread )
 117 {
 118     struct mutex *mutex = (struct mutex *)obj;
 119     assert( obj->ops == &mutex_ops );
 120     return (!mutex->count || (mutex->owner == thread));
 121 }
 122
 123 static int mutex_satisfied( struct object *obj, struct thread *thread )
 124 {
 125     struct mutex *mutex = (struct mutex *)obj;
 126     assert( obj->ops == &mutex_ops );
 127     assert( !mutex->count || (mutex->owner == thread) );
 128
 129     if (!mutex->count++)  /* FIXME: avoid wrap-around */
 130     {
 131         assert( !mutex->owner );
 132         mutex->owner = thread;
 133         list_add_head( &thread->mutex_list, &mutex->entry );
 134     }
 135     if (!mutex->abandoned) return 0;
 136     mutex->abandoned = 0;
 137     return 1;
 138 }
 139
 140 static int mutex_signal( struct object *obj, unsigned int access )
 141 {
 142     struct mutex *mutex = (struct mutex *)obj;
 143     assert( obj->ops == &mutex_ops );
 144
 145     if (!(access & SYNCHRONIZE))  /* FIXME: MUTEX_MODIFY_STATE? */
 146     {
 147         set_error( STATUS_ACCESS_DENIED );
 148         return 0;
 149     }
 150     if (!mutex->count || (mutex->owner != current))
 151     {
 152         set_error( STATUS_MUTANT_NOT_OWNED );
 153         return 0;
 154     }
 155     if (!--mutex->count) do_release( mutex );
 156     return 1;
 157 }
 158
 159 static void mutex_destroy( struct object *obj )
 160 {
 161     struct mutex *mutex = (struct mutex *)obj;
 162     assert( obj->ops == &mutex_ops );
 163
 164     if (!mutex->count) return;
 165     mutex->count = 0;
 166     do_release( mutex );
 167 }
 168
 169 /* create a mutex */
 170 DECL_HANDLER(create_mutex)
 171 {
 172     struct mutex *mutex;
 173
 174     reply->handle = 0;
 175     if ((mutex = create_mutex( get_req_data(), get_req_data_size(), req->owned )))
 176     {
 177         reply->handle = alloc_handle( current->process, mutex, req->access,
 178                                       req->attributes & OBJ_INHERIT );
 179         release_object( mutex );
 180     }
 181 }
 182
 183 /* open a handle to a mutex */
 184 DECL_HANDLER(open_mutex)
 185 {
 186     reply->handle = open_object( sync_namespace, get_req_data(), get_req_data_size(),
 187                                  &mutex_ops, req->access, req->attributes );
 188 }
 189
 190 /* release a mutex */
 191 DECL_HANDLER(release_mutex)
 192 {
 193     struct mutex *mutex;
 194
 195     if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
 196                                                  MUTEX_MODIFY_STATE, &mutex_ops )))
 197     {
 198         if (!mutex->count || (mutex->owner != current)) set_error( STATUS_MUTANT_NOT_OWNED );
 199         else
 200         {
 201             reply->prev_count = mutex->count;
 202             if (!--mutex->count) do_release( mutex );
 203         }
 204         release_object( mutex );
 205     }
 206 }