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     no_close_handle,           /* close_handle */
  60     mutex_destroy              /* destroy */
  61 };
  62
  63
  64 static struct mutex *create_mutex( const WCHAR *name, size_t len, int owned )
  65 {
  66     struct mutex *mutex;
  67
  68     if ((mutex = create_named_object( sync_namespace, &mutex_ops, name, len )))
  69     {
  70         if (get_error() != STATUS_OBJECT_NAME_COLLISION)
  71         {
  72             /* initialize it if it didn't already exist */
  73             mutex->count = 0;
  74             mutex->owner = NULL;
  75             mutex->abandoned = 0;
  76             if (owned) mutex_satisfied( &mutex->obj, current );
  77         }
  78     }
  79     return mutex;
  80 }
  81
  82 /* release a mutex once the recursion count is 0 */
  83 static void do_release( struct mutex *mutex )
  84 {
  85     assert( !mutex->count );
  86     /* remove the mutex from the thread list of owned mutexes */
  87     list_remove( &mutex->entry );
  88     mutex->owner = NULL;
  89     wake_up( &mutex->obj, 0 );
  90 }
  91
  92 void abandon_mutexes( struct thread *thread )
  93 {
  94     struct list *ptr;
  95
  96     while ((ptr = list_head( &thread->mutex_list )) != NULL)
  97     {
  98         struct mutex *mutex = LIST_ENTRY( ptr, struct mutex, entry );
  99         assert( mutex->owner == thread );
 100         mutex->count = 0;
 101         mutex->abandoned = 1;
 102         do_release( mutex );
 103     }
 104 }
 105
 106 static void mutex_dump( struct object *obj, int verbose )
 107 {
 108     struct mutex *mutex = (struct mutex *)obj;
 109     assert( obj->ops == &mutex_ops );
 110     fprintf( stderr, "Mutex count=%u owner=%p ", mutex->count, mutex->owner );
 111     dump_object_name( &mutex->obj );
 112     fputc( '\n', stderr );
 113 }
 114
 115 static int mutex_signaled( struct object *obj, struct thread *thread )
 116 {
 117     struct mutex *mutex = (struct mutex *)obj;
 118     assert( obj->ops == &mutex_ops );
 119     return (!mutex->count || (mutex->owner == thread));
 120 }
 121
 122 static int mutex_satisfied( struct object *obj, struct thread *thread )
 123 {
 124     struct mutex *mutex = (struct mutex *)obj;
 125     assert( obj->ops == &mutex_ops );
 126     assert( !mutex->count || (mutex->owner == thread) );
 127
 128     if (!mutex->count++)  /* FIXME: avoid wrap-around */
 129     {
 130         assert( !mutex->owner );
 131         mutex->owner = thread;
 132         list_add_head( &thread->mutex_list, &mutex->entry );
 133     }
 134     if (!mutex->abandoned) return 0;
 135     mutex->abandoned = 0;
 136     return 1;
 137 }
 138
 139 static int mutex_signal( struct object *obj, unsigned int access )
 140 {
 141     struct mutex *mutex = (struct mutex *)obj;
 142     assert( obj->ops == &mutex_ops );
 143
 144     if (!(access & SYNCHRONIZE))  /* FIXME: MUTEX_MODIFY_STATE? */
 145     {
 146         set_error( STATUS_ACCESS_DENIED );
 147         return 0;
 148     }
 149     if (!mutex->count || (mutex->owner != current))
 150     {
 151         set_error( STATUS_MUTANT_NOT_OWNED );
 152         return 0;
 153     }
 154     if (!--mutex->count) do_release( mutex );
 155     return 1;
 156 }
 157
 158 static void mutex_destroy( struct object *obj )
 159 {
 160     struct mutex *mutex = (struct mutex *)obj;
 161     assert( obj->ops == &mutex_ops );
 162
 163     if (!mutex->count) return;
 164     mutex->count = 0;
 165     do_release( mutex );
 166 }
 167
 168 /* create a mutex */
 169 DECL_HANDLER(create_mutex)
 170 {
 171     struct mutex *mutex;
 172
 173     reply->handle = 0;
 174     if ((mutex = create_mutex( get_req_data(), get_req_data_size(), req->owned )))
 175     {
 176         reply->handle = alloc_handle( current->process, mutex, req->access, req->inherit );
 177         release_object( mutex );
 178     }
 179 }
 180
 181 /* open a handle to a mutex */
 182 DECL_HANDLER(open_mutex)
 183 {
 184     reply->handle = open_object( sync_namespace, get_req_data(), get_req_data_size(),
 185                                  &mutex_ops, req->access, req->inherit );
 186 }
 187
 188 /* release a mutex */
 189 DECL_HANDLER(release_mutex)
 190 {
 191     struct mutex *mutex;
 192
 193     if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
 194                                                  MUTEX_MODIFY_STATE, &mutex_ops )))
 195     {
 196         if (!mutex->count || (mutex->owner != current)) set_error( STATUS_MUTANT_NOT_OWNED );
 197         else
 198         {
 199             reply->prev_count = mutex->count;
 200             if (!--mutex->count) do_release( mutex );
 201         }
 202         release_object( mutex );
 203     }
 204 }