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