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