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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include "config.h"
  22
  23 #include <assert.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <stdarg.h>
  27 #include <sys/types.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 #include "security.h"
  38
  39 static const WCHAR mutex_name[] = {'M','u','t','a','n','t'};
  40
  41 struct type_descr mutex_type =
  42 {
  43     { mutex_name, sizeof(mutex_name) },   /* name */
  44     MUTANT_ALL_ACCESS,                    /* valid_access */
  45     {                                     /* mapping */
  46         STANDARD_RIGHTS_READ | MUTANT_QUERY_STATE,
  47         STANDARD_RIGHTS_WRITE,
  48         STANDARD_RIGHTS_EXECUTE | SYNCHRONIZE,
  49         MUTANT_ALL_ACCESS
  50     },
  51 };
  52
  53 struct mutex
  54 {
  55     struct object  obj;             /* object header */
  56     struct thread *owner;           /* mutex owner */
  57     unsigned int   count;           /* recursion count */
  58     int            abandoned;       /* has it been abandoned? */
  59     struct list    entry;           /* entry in owner thread mutex list */
  60 };
  61
  62 static void mutex_dump( struct object *obj, int verbose );
  63 static int mutex_signaled( struct object *obj, struct wait_queue_entry *entry );
  64 static void mutex_satisfied( struct object *obj, struct wait_queue_entry *entry );
  65 static void mutex_destroy( struct object *obj );
  66 static int mutex_signal( struct object *obj, unsigned int access );
  67
  68 static const struct object_ops mutex_ops =
  69 {
  70     sizeof(struct mutex),      /* size */
  71     &mutex_type,               /* type */
  72     mutex_dump,                /* dump */
  73     add_queue,                 /* add_queue */
  74     remove_queue,              /* remove_queue */
  75     mutex_signaled,            /* signaled */
  76     mutex_satisfied,           /* satisfied */
  77     mutex_signal,              /* signal */
  78     no_get_fd,                 /* get_fd */
  79     default_map_access,        /* map_access */
  80     default_get_sd,            /* get_sd */
  81     default_set_sd,            /* set_sd */
  82     default_get_full_name,     /* get_full_name */
  83     no_lookup_name,            /* lookup_name */
  84     directory_link_name,       /* link_name */
  85     default_unlink_name,       /* unlink_name */
  86     no_open_file,              /* open_file */
  87     no_kernel_obj_list,        /* get_kernel_obj_list */
  88     no_close_handle,           /* close_handle */
  89     mutex_destroy              /* destroy */
  90 };
  91
  92
  93 /* grab a mutex for a given thread */
  94 static void do_grab( struct mutex *mutex, struct thread *thread )
  95 {
  96     assert( !mutex->count || (mutex->owner == thread) );
  97
  98     if (!mutex->count++)  /* FIXME: avoid wrap-around */
  99     {
 100         assert( !mutex->owner );
 101         mutex->owner = thread;
 102         list_add_head( &thread->mutex_list, &mutex->entry );
 103     }
 104 }
 105
 106 /* release a mutex once the recursion count is 0 */
 107 static void do_release( struct mutex *mutex )
 108 {
 109     assert( !mutex->count );
 110     /* remove the mutex from the thread list of owned mutexes */
 111     list_remove( &mutex->entry );
 112     mutex->owner = NULL;
 113     wake_up( &mutex->obj, 0 );
 114 }
 115
 116 static struct mutex *create_mutex( struct object *root, const struct unicode_str *name,
 117                                    unsigned int attr, int owned, const struct security_descriptor *sd )
 118 {
 119     struct mutex *mutex;
 120
 121     if ((mutex = create_named_object( root, &mutex_ops, name, attr, sd )))
 122     {
 123         if (get_error() != STATUS_OBJECT_NAME_EXISTS)
 124         {
 125             /* initialize it if it didn't already exist */
 126             mutex->count = 0;
 127             mutex->owner = NULL;
 128             mutex->abandoned = 0;
 129             if (owned) do_grab( mutex, current );
 130         }
 131     }
 132     return mutex;
 133 }
 134
 135 void abandon_mutexes( struct thread *thread )
 136 {
 137     struct list *ptr;
 138
 139     while ((ptr = list_head( &thread->mutex_list )) != NULL)
 140     {
 141         struct mutex *mutex = LIST_ENTRY( ptr, struct mutex, entry );
 142         assert( mutex->owner == thread );
 143         mutex->count = 0;
 144         mutex->abandoned = 1;
 145         do_release( mutex );
 146     }
 147 }
 148
 149 static void mutex_dump( struct object *obj, int verbose )
 150 {
 151     struct mutex *mutex = (struct mutex *)obj;
 152     assert( obj->ops == &mutex_ops );
 153     fprintf( stderr, "Mutex count=%u owner=%p\n", mutex->count, mutex->owner );
 154 }
 155
 156 static int mutex_signaled( struct object *obj, struct wait_queue_entry *entry )
 157 {
 158     struct mutex *mutex = (struct mutex *)obj;
 159     assert( obj->ops == &mutex_ops );
 160     return (!mutex->count || (mutex->owner == get_wait_queue_thread( entry )));
 161 }
 162
 163 static void mutex_satisfied( struct object *obj, struct wait_queue_entry *entry )
 164 {
 165     struct mutex *mutex = (struct mutex *)obj;
 166     assert( obj->ops == &mutex_ops );
 167
 168     do_grab( mutex, get_wait_queue_thread( entry ));
 169     if (mutex->abandoned) make_wait_abandoned( entry );
 170     mutex->abandoned = 0;
 171 }
 172
 173 static int mutex_signal( struct object *obj, unsigned int access )
 174 {
 175     struct mutex *mutex = (struct mutex *)obj;
 176     assert( obj->ops == &mutex_ops );
 177
 178     if (!(access & SYNCHRONIZE))
 179     {
 180         set_error( STATUS_ACCESS_DENIED );
 181         return 0;
 182     }
 183     if (!mutex->count || (mutex->owner != current))
 184     {
 185         set_error( STATUS_MUTANT_NOT_OWNED );
 186         return 0;
 187     }
 188     if (!--mutex->count) do_release( mutex );
 189     return 1;
 190 }
 191
 192 static void mutex_destroy( struct object *obj )
 193 {
 194     struct mutex *mutex = (struct mutex *)obj;
 195     assert( obj->ops == &mutex_ops );
 196
 197     if (!mutex->count) return;
 198     mutex->count = 0;
 199     do_release( mutex );
 200 }
 201
 202 /* create a mutex */
 203 DECL_HANDLER(create_mutex)
 204 {
 205     struct mutex *mutex;
 206     struct unicode_str name;
 207     struct object *root;
 208     const struct security_descriptor *sd;
 209     const struct object_attributes *objattr = get_req_object_attributes( &sd, &name, &root );
 210
 211     if (!objattr) return;
 212
 213     if ((mutex = create_mutex( root, &name, objattr->attributes, req->owned, sd )))
 214     {
 215         if (get_error() == STATUS_OBJECT_NAME_EXISTS)
 216             reply->handle = alloc_handle( current->process, mutex, req->access, objattr->attributes );
 217         else
 218             reply->handle = alloc_handle_no_access_check( current->process, mutex,
 219                                                           req->access, objattr->attributes );
 220         release_object( mutex );
 221     }
 222
 223     if (root) release_object( root );
 224 }
 225
 226 /* open a handle to a mutex */
 227 DECL_HANDLER(open_mutex)
 228 {
 229     struct unicode_str name = get_req_unicode_str();
 230
 231     reply->handle = open_object( current->process, req->rootdir, req->access,
 232                                  &mutex_ops, &name, req->attributes );
 233 }
 234
 235 /* release a mutex */
 236 DECL_HANDLER(release_mutex)
 237 {
 238     struct mutex *mutex;
 239
 240     if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
 241                                                  0, &mutex_ops )))
 242     {
 243         if (!mutex->count || (mutex->owner != current)) set_error( STATUS_MUTANT_NOT_OWNED );
 244         else
 245         {
 246             reply->prev_count = mutex->count;
 247             if (!--mutex->count) do_release( mutex );
 248         }
 249         release_object( mutex );
 250     }
 251 }
 252
 253 /* return details about the mutex */
 254 DECL_HANDLER(query_mutex)
 255 {
 256     struct mutex *mutex;
 257
 258     if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle,
 259                                                  MUTANT_QUERY_STATE, &mutex_ops )))
 260     {
 261         reply->count = mutex->count;
 262         reply->owned = (mutex->owner == current);
 263         reply->abandoned = mutex->abandoned;
 264
 265         release_object( mutex );
 266     }
 267 }