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( struct directory *root, const struct unicode_str *name,
  70                                    unsigned int attr, int owned )
  71 {
  72     struct mutex *mutex;
  73
  74     if ((mutex = create_named_object_dir( root, name, attr, &mutex_ops )))
  75     {
  76         if (get_error() != STATUS_OBJECT_NAME_EXISTS)
  77         {
  78             /* initialize it if it didn't already exist */
  79             mutex->count = 0;
  80             mutex->owner = NULL;
  81             mutex->abandoned = 0;
  82             if (owned) mutex_satisfied( &mutex->obj, current );
  83         }
  84     }
  85     return mutex;
  86 }
  87
  88 /* release a mutex once the recursion count is 0 */
  89 static void do_release( struct mutex *mutex )
  90 {
  91     assert( !mutex->count );
  92     /* remove the mutex from the thread list of owned mutexes */
  93     list_remove( &mutex->entry );
  94     mutex->owner = NULL;
  95     wake_up( &mutex->obj, 0 );
  96 }
  97
  98 void abandon_mutexes( struct thread *thread )
  99 {
 100     struct list *ptr;
 101
 102     while ((ptr = list_head( &thread->mutex_list )) != NULL)
 103     {
 104         struct mutex *mutex = LIST_ENTRY( ptr, struct mutex, entry );
 105         assert( mutex->owner == thread );
 106         mutex->count = 0;
 107         mutex->abandoned = 1;
 108         do_release( mutex );
 109     }
 110 }
 111
 112 static void mutex_dump( struct object *obj, int verbose )
 113 {
 114     struct mutex *mutex = (struct mutex *)obj;
 115     assert( obj->ops == &mutex_ops );
 116     fprintf( stderr, "Mutex count=%u owner=%p ", mutex->count, mutex->owner );
 117     dump_object_name( &mutex->obj );
 118     fputc( '\n', stderr );
 119 }
 120
 121 static int mutex_signaled( struct object *obj, struct thread *thread )
 122 {
 123     struct mutex *mutex = (struct mutex *)obj;
 124     assert( obj->ops == &mutex_ops );
 125     return (!mutex->count || (mutex->owner == thread));
 126 }
 127
 128 static int mutex_satisfied( struct object *obj, struct thread *thread )
 129 {
 130     struct mutex *mutex = (struct mutex *)obj;
 131     assert( obj->ops == &mutex_ops );
 132     assert( !mutex->count || (mutex->owner == thread) );
 133
 134     if (!mutex->count++)  /* FIXME: avoid wrap-around */
 135     {
 136         assert( !mutex->owner );
 137         mutex->owner = thread;
 138         list_add_head( &thread->mutex_list, &mutex->entry );
 139     }
 140     if (!mutex->abandoned) return 0;
 141     mutex->abandoned = 0;
 142     return 1;
 143 }
 144
 145 static int mutex_signal( struct object *obj, unsigned int access )
 146 {
 147     struct mutex *mutex = (struct mutex *)obj;
 148     assert( obj->ops == &mutex_ops );
 149
 150     if (!(access & SYNCHRONIZE))  /* FIXME: MUTEX_MODIFY_STATE? */
 151     {
 152         set_error( STATUS_ACCESS_DENIED );
 153         return 0;
 154     }
 155     if (!mutex->count || (mutex->owner != current))
 156     {
 157         set_error( STATUS_MUTANT_NOT_OWNED );
 158         return 0;
 159     }
 160     if (!--mutex->count) do_release( mutex );
 161     return 1;
 162 }
 163
 164 static void mutex_destroy( struct object *obj )
 165 {
 166     struct mutex *mutex = (struct mutex *)obj;
 167     assert( obj->ops == &mutex_ops );
 168
 169     if (!mutex->count) return;
 170     mutex->count = 0;
 171     do_release( mutex );
 172 }
 173
 174 /* create a mutex */
 175 DECL_HANDLER(create_mutex)
 176 {
 177     struct mutex *mutex;
 178     struct unicode_str name;
 179     struct directory *root = NULL;
 180
 181     reply->handle = 0;
 182     get_req_unicode_str( &name );
 183     if (req->rootdir && !(root = get_directory_obj( current->process, req->rootdir, 0 )))
 184         return;
 185
 186     if ((mutex = create_mutex( root, &name, req->attributes, req->owned )))
 187     {
 188         reply->handle = alloc_handle( current->process, mutex, req->access,
 189                                       req->attributes & OBJ_INHERIT );
 190         release_object( mutex );
 191     }
 192
 193     if (root) release_object( root );
 194 }
 195
 196 /* open a handle to a mutex */
 197 DECL_HANDLER(open_mutex)
 198 {
 199     struct unicode_str name;
 200     struct directory *root = NULL;
 201     struct mutex *mutex;
 202
 203     get_req_unicode_str( &name );
 204     if (req->rootdir && !(root = get_directory_obj( current->process, req->rootdir, 0 )))
 205         return;
 206
 207     if ((mutex = open_object_dir( root, &name, req->attributes, &mutex_ops )))
 208     {
 209         reply->handle = alloc_handle( current->process, &mutex->obj, req->access,
 210                                       req->attributes & OBJ_INHERIT );
 211         release_object( mutex );
 212     }
 213
 214     if (root) release_object( root );
 215 }
 216
 217 /* release a mutex */
 218 DECL_HANDLER(release_mutex)
 219 {
 220     struct mutex *mutex;
 221
 222     if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
 223                                                  MUTEX_MODIFY_STATE, &mutex_ops )))
 224     {
 225         if (!mutex->count || (mutex->owner != current)) set_error( STATUS_MUTANT_NOT_OWNED );
 226         else
 227         {
 228             reply->prev_count = mutex->count;
 229             if (!--mutex->count) do_release( mutex );
 230         }
 231         release_object( mutex );
 232     }
 233 }