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