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, unsigned int attr,
  66                                    int owned )
  67 {
  68     struct mutex *mutex;
  69
  70     if ((mutex = create_named_object( sync_namespace, &mutex_ops, name, len, attr )))
  71     {
  72         if (get_error() != STATUS_OBJECT_NAME_COLLISION)
  73         {
  74             /* initialize it if it didn't already exist */
  75             mutex->count = 0;
  76             mutex->owner = NULL;
  77             mutex->abandoned = 0;
  78             if (owned) mutex_satisfied( &mutex->obj, current );
  79         }
  80     }
  81     return mutex;
  82 }
  83
  84 /* release a mutex once the recursion count is 0 */
  85 static void do_release( struct mutex *mutex )
  86 {
  87     assert( !mutex->count );
  88     /* remove the mutex from the thread list of owned mutexes */
  89     list_remove( &mutex->entry );
  90     mutex->owner = NULL;
  91     wake_up( &mutex->obj, 0 );
  92 }
  93
  94 void abandon_mutexes( struct thread *thread )
  95 {
  96     struct list *ptr;
  97
  98     while ((ptr = list_head( &thread->mutex_list )) != NULL)
  99     {
 100         struct mutex *mutex = LIST_ENTRY( ptr, struct mutex, entry );
 101         assert( mutex->owner == thread );
 102         mutex->count = 0;
 103         mutex->abandoned = 1;
 104         do_release( mutex );
 105     }
 106 }
 107
 108 static void mutex_dump( struct object *obj, int verbose )
 109 {
 110     struct mutex *mutex = (struct mutex *)obj;
 111     assert( obj->ops == &mutex_ops );
 112     fprintf( stderr, "Mutex count=%u owner=%p ", mutex->count, mutex->owner );
 113     dump_object_name( &mutex->obj );
 114     fputc( '\n', stderr );
 115 }
 116
 117 static int mutex_signaled( struct object *obj, struct thread *thread )
 118 {
 119     struct mutex *mutex = (struct mutex *)obj;
 120     assert( obj->ops == &mutex_ops );
 121     return (!mutex->count || (mutex->owner == thread));
 122 }
 123
 124 static int mutex_satisfied( struct object *obj, struct thread *thread )
 125 {
 126     struct mutex *mutex = (struct mutex *)obj;
 127     assert( obj->ops == &mutex_ops );
 128     assert( !mutex->count || (mutex->owner == thread) );
 129
 130     if (!mutex->count++)  /* FIXME: avoid wrap-around */
 131     {
 132         assert( !mutex->owner );
 133         mutex->owner = thread;
 134         list_add_head( &thread->mutex_list, &mutex->entry );
 135     }
 136     if (!mutex->abandoned) return 0;
 137     mutex->abandoned = 0;
 138     return 1;
 139 }
 140
 141 static int mutex_signal( struct object *obj, unsigned int access )
 142 {
 143     struct mutex *mutex = (struct mutex *)obj;
 144     assert( obj->ops == &mutex_ops );
 145
 146     if (!(access & SYNCHRONIZE))  /* FIXME: MUTEX_MODIFY_STATE? */
 147     {
 148         set_error( STATUS_ACCESS_DENIED );
 149         return 0;
 150     }
 151     if (!mutex->count || (mutex->owner != current))
 152     {
 153         set_error( STATUS_MUTANT_NOT_OWNED );
 154         return 0;
 155     }
 156     if (!--mutex->count) do_release( mutex );
 157     return 1;
 158 }
 159
 160 static void mutex_destroy( struct object *obj )
 161 {
 162     struct mutex *mutex = (struct mutex *)obj;
 163     assert( obj->ops == &mutex_ops );
 164
 165     if (!mutex->count) return;
 166     mutex->count = 0;
 167     do_release( mutex );
 168 }
 169
 170 /* create a mutex */
 171 DECL_HANDLER(create_mutex)
 172 {
 173     struct mutex *mutex;
 174
 175     reply->handle = 0;
 176     if ((mutex = create_mutex( get_req_data(), get_req_data_size(), req->attributes,
 177                                req->owned )))
 178     {
 179         reply->handle = alloc_handle( current->process, mutex, req->access,
 180                                       req->attributes & OBJ_INHERIT );
 181         release_object( mutex );
 182     }
 183 }
 184
 185 /* open a handle to a mutex */
 186 DECL_HANDLER(open_mutex)
 187 {
 188     reply->handle = open_object( sync_namespace, get_req_data(), get_req_data_size(),
 189                                  &mutex_ops, req->access, req->attributes );
 190 }
 191
 192 /* release a mutex */
 193 DECL_HANDLER(release_mutex)
 194 {
 195     struct mutex *mutex;
 196
 197     if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
 198                                                  MUTEX_MODIFY_STATE, &mutex_ops )))
 199     {
 200         if (!mutex->count || (mutex->owner != current)) set_error( STATUS_MUTANT_NOT_OWNED );
 201         else
 202         {
 203             reply->prev_count = mutex->count;
 204             if (!--mutex->count) do_release( mutex );
 205         }
 206         release_object( mutex );
 207     }
 208 }