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 "winnt.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 mutex  *next;
  41     struct mutex  *prev;
  42 };
  43
  44 static void mutex_dump( struct object *obj, int verbose );
  45 static int mutex_signaled( struct object *obj, struct thread *thread );
  46 static int mutex_satisfied( struct object *obj, struct thread *thread );
  47 static void mutex_destroy( struct object *obj );
  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     NULL,                      /* get_poll_events */
  58     NULL,                      /* poll_event */
  59     no_get_fd,                 /* get_fd */
  60     no_flush,                  /* flush */
  61     no_get_file_info,          /* get_file_info */
  62     NULL,                      /* queue_async */
  63     mutex_destroy              /* destroy */
  64 };
  65
  66
  67 static struct mutex *create_mutex( const WCHAR *name, size_t len, int owned )
  68 {
  69     struct mutex *mutex;
  70
  71     if ((mutex = create_named_object( sync_namespace, &mutex_ops, name, len )))
  72     {
  73         if (get_error() != STATUS_OBJECT_NAME_COLLISION)
  74         {
  75             /* initialize it if it didn't already exist */
  76             mutex->count = 0;
  77             mutex->owner = NULL;
  78             mutex->abandoned = 0;
  79             mutex->next = mutex->prev = NULL;
  80             if (owned) mutex_satisfied( &mutex->obj, current );
  81         }
  82     }
  83     return mutex;
  84 }
  85
  86 /* release a mutex once the recursion count is 0 */
  87 static void do_release( struct mutex *mutex )
  88 {
  89     assert( !mutex->count );
  90     /* remove the mutex from the thread list of owned mutexes */
  91     if (mutex->next) mutex->next->prev = mutex->prev;
  92     if (mutex->prev) mutex->prev->next = mutex->next;
  93     else mutex->owner->mutex = mutex->next;
  94     mutex->owner = NULL;
  95     mutex->next = mutex->prev = NULL;
  96     wake_up( &mutex->obj, 0 );
  97 }
  98
  99 void abandon_mutexes( struct thread *thread )
 100 {
 101     while (thread->mutex)
 102     {
 103         struct mutex *mutex = thread->mutex;
 104         assert( mutex->owner == thread );
 105         mutex->count = 0;
 106         mutex->abandoned = 1;
 107         do_release( mutex );
 108     }
 109 }
 110
 111 static void mutex_dump( struct object *obj, int verbose )
 112 {
 113     struct mutex *mutex = (struct mutex *)obj;
 114     assert( obj->ops == &mutex_ops );
 115     fprintf( stderr, "Mutex count=%u owner=%p ", mutex->count, mutex->owner );
 116     dump_object_name( &mutex->obj );
 117     fputc( '\n', stderr );
 118 }
 119
 120 static int mutex_signaled( struct object *obj, struct thread *thread )
 121 {
 122     struct mutex *mutex = (struct mutex *)obj;
 123     assert( obj->ops == &mutex_ops );
 124     return (!mutex->count || (mutex->owner == thread));
 125 }
 126
 127 static int mutex_satisfied( struct object *obj, struct thread *thread )
 128 {
 129     struct mutex *mutex = (struct mutex *)obj;
 130     assert( obj->ops == &mutex_ops );
 131     assert( !mutex->count || (mutex->owner == thread) );
 132
 133     if (!mutex->count++)  /* FIXME: avoid wrap-around */
 134     {
 135         assert( !mutex->owner );
 136         mutex->owner = thread;
 137         mutex->prev  = NULL;
 138         if ((mutex->next = thread->mutex)) mutex->next->prev = mutex;
 139         thread->mutex = mutex;
 140     }
 141     if (!mutex->abandoned) return 0;
 142     mutex->abandoned = 0;
 143     return 1;
 144 }
 145
 146 static void mutex_destroy( struct object *obj )
 147 {
 148     struct mutex *mutex = (struct mutex *)obj;
 149     assert( obj->ops == &mutex_ops );
 150
 151     if (!mutex->count) return;
 152     mutex->count = 0;
 153     do_release( mutex );
 154 }
 155
 156 /* create a mutex */
 157 DECL_HANDLER(create_mutex)
 158 {
 159     struct mutex *mutex;
 160
 161     reply->handle = 0;
 162     if ((mutex = create_mutex( get_req_data(), get_req_data_size(), req->owned )))
 163     {
 164         reply->handle = alloc_handle( current->process, mutex, MUTEX_ALL_ACCESS, req->inherit );
 165         release_object( mutex );
 166     }
 167 }
 168
 169 /* open a handle to a mutex */
 170 DECL_HANDLER(open_mutex)
 171 {
 172     reply->handle = open_object( sync_namespace, get_req_data(), get_req_data_size(),
 173                                  &mutex_ops, req->access, req->inherit );
 174 }
 175
 176 /* release a mutex */
 177 DECL_HANDLER(release_mutex)
 178 {
 179     struct mutex *mutex;
 180
 181     if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
 182                                                  MUTEX_MODIFY_STATE, &mutex_ops )))
 183     {
 184         if (!mutex->count || (mutex->owner != current)) set_error( STATUS_MUTANT_NOT_OWNED );
 185         else if (!--mutex->count) do_release( mutex );
 186         release_object( mutex );
 187     }
 188 }