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 #include <stdarg.h>
  28
  29 #include "ntstatus.h"
  30 #define WIN32_NO_STATUS
  31 #include "windef.h"
  32 #include "winternl.h"
  33
  34 #include "handle.h"
  35 #include "thread.h"
  36 #include "request.h"
  37
  38 struct mutex
  39 {
  40     struct object  obj;             /* object header */
  41     struct thread *owner;           /* mutex owner */
  42     unsigned int   count;           /* recursion count */
  43     int            abandoned;       /* has it been abandoned? */
  44     struct list    entry;           /* entry in owner thread mutex list */
  45 };
  46
  47 static void mutex_dump( struct object *obj, int verbose );
  48 static int mutex_signaled( struct object *obj, struct thread *thread );
  49 static int mutex_satisfied( struct object *obj, struct thread *thread );
  50 static void mutex_destroy( struct object *obj );
  51 static int mutex_signal( struct object *obj, unsigned int access );
  52
  53 static const struct object_ops mutex_ops =
  54 {
  55     sizeof(struct mutex),      /* size */
  56     mutex_dump,                /* dump */
  57     add_queue,                 /* add_queue */
  58     remove_queue,              /* remove_queue */
  59     mutex_signaled,            /* signaled */
  60     mutex_satisfied,           /* satisfied */
  61     mutex_signal,              /* signal */
  62     no_get_fd,                 /* get_fd */
  63     no_lookup_name,            /* lookup_name */
  64     no_close_handle,           /* close_handle */
  65     mutex_destroy              /* destroy */
  66 };
  67
  68
  69 static struct mutex *create_mutex( const struct unicode_str *name, unsigned int attr, int owned )
  70 {
  71     struct mutex *mutex;
  72
  73     if ((mutex = create_named_object( sync_namespace, &mutex_ops, name, attr )))
  74     {
  75         if (get_error() != STATUS_OBJECT_NAME_EXISTS)
  76         {
  77             /* initialize it if it didn't already exist */
  78             mutex->count = 0;
  79             mutex->owner = NULL;
  80             mutex->abandoned = 0;
  81             if (owned) mutex_satisfied( &mutex->obj, current );
  82         }
  83     }
  84     return mutex;
  85 }
  86
  87 /* release a mutex once the recursion count is 0 */
  88 static void do_release( struct mutex *mutex )
  89 {
  90     assert( !mutex->count );
  91     /* remove the mutex from the thread list of owned mutexes */
  92     list_remove( &mutex->entry );
  93     mutex->owner = NULL;
  94     wake_up( &mutex->obj, 0 );
  95 }
  96
  97 void abandon_mutexes( struct thread *thread )
  98 {
  99     struct list *ptr;
 100
 101     while ((ptr = list_head( &thread->mutex_list )) != NULL)
 102     {
 103         struct mutex *mutex = LIST_ENTRY( ptr, struct mutex, entry );
 104         assert( mutex->owner == thread );
 105         mutex->count = 0;
 106         mutex->abandoned = 1;
 107         do_release( mutex );
 108     }
 109 }
 110
 111 static void mutex_dump( struct object *obj, int verbose )
 112 {
 113     struct mutex *mutex = (struct mutex *)obj;
 114     assert( obj->ops == &mutex_ops );
 115     fprintf( stderr, "Mutex count=%u owner=%p ", mutex->count, mutex->owner );
 116     dump_object_name( &mutex->obj );
 117     fputc( '\n', stderr );
 118 }
 119
 120 static int mutex_signaled( struct object *obj, struct thread *thread )
 121 {
 122     struct mutex *mutex = (struct mutex *)obj;
 123     assert( obj->ops == &mutex_ops );
 124     return (!mutex->count || (mutex->owner == thread));
 125 }
 126
 127 static int mutex_satisfied( struct object *obj, struct thread *thread )
 128 {
 129     struct mutex *mutex = (struct mutex *)obj;
 130     assert( obj->ops == &mutex_ops );
 131     assert( !mutex->count || (mutex->owner == thread) );
 132
 133     if (!mutex->count++)  /* FIXME: avoid wrap-around */
 134     {
 135         assert( !mutex->owner );
 136         mutex->owner = thread;
 137         list_add_head( &thread->mutex_list, &mutex->entry );
 138     }
 139     if (!mutex->abandoned) return 0;
 140     mutex->abandoned = 0;
 141     return 1;
 142 }
 143
 144 static int mutex_signal( struct object *obj, unsigned int access )
 145 {
 146     struct mutex *mutex = (struct mutex *)obj;
 147     assert( obj->ops == &mutex_ops );
 148
 149     if (!(access & SYNCHRONIZE))  /* FIXME: MUTEX_MODIFY_STATE? */
 150     {
 151         set_error( STATUS_ACCESS_DENIED );
 152         return 0;
 153     }
 154     if (!mutex->count || (mutex->owner != current))
 155     {
 156         set_error( STATUS_MUTANT_NOT_OWNED );
 157         return 0;
 158     }
 159     if (!--mutex->count) do_release( mutex );
 160     return 1;
 161 }
 162
 163 static void mutex_destroy( struct object *obj )
 164 {
 165     struct mutex *mutex = (struct mutex *)obj;
 166     assert( obj->ops == &mutex_ops );
 167
 168     if (!mutex->count) return;
 169     mutex->count = 0;
 170     do_release( mutex );
 171 }
 172
 173 /* create a mutex */
 174 DECL_HANDLER(create_mutex)
 175 {
 176     struct mutex *mutex;
 177     struct unicode_str name;
 178
 179     reply->handle = 0;
 180     get_req_unicode_str( &name );
 181     if ((mutex = create_mutex( &name, req->attributes, req->owned )))
 182     {
 183         reply->handle = alloc_handle( current->process, mutex, req->access,
 184                                       req->attributes & OBJ_INHERIT );
 185         release_object( mutex );
 186     }
 187 }
 188
 189 /* open a handle to a mutex */
 190 DECL_HANDLER(open_mutex)
 191 {
 192     struct unicode_str name;
 193
 194     get_req_unicode_str( &name );
 195     reply->handle = open_object( sync_namespace, &name, &mutex_ops, req->access, req->attributes );
 196 }
 197
 198 /* release a mutex */
 199 DECL_HANDLER(release_mutex)
 200 {
 201     struct mutex *mutex;
 202
 203     if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
 204                                                  MUTEX_MODIFY_STATE, &mutex_ops )))
 205     {
 206         if (!mutex->count || (mutex->owner != current)) set_error( STATUS_MUTANT_NOT_OWNED );
 207         else
 208         {
 209             reply->prev_count = mutex->count;
 210             if (!--mutex->count) do_release( mutex );
 211         }
 212         release_object( mutex );
 213     }
 214 }