/* * Server-side mutex management * * Copyright (C) 1998 Alexandre Julliard * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA */ #include "config.h" #include #include #include #include #include "ntstatus.h" #define WIN32_NO_STATUS #include "windef.h" #include "winternl.h" #include "handle.h" #include "thread.h" #include "request.h" #include "security.h" static const WCHAR mutex_name[] = {'M','u','t','a','n','t'}; struct type_descr mutex_type = { { mutex_name, sizeof(mutex_name) }, /* name */ MUTANT_ALL_ACCESS, /* valid_access */ { /* mapping */ STANDARD_RIGHTS_READ | MUTANT_QUERY_STATE, STANDARD_RIGHTS_WRITE, STANDARD_RIGHTS_EXECUTE | SYNCHRONIZE, MUTANT_ALL_ACCESS }, }; struct mutex { struct object obj; /* object header */ struct thread *owner; /* mutex owner */ unsigned int count; /* recursion count */ int abandoned; /* has it been abandoned? */ struct list entry; /* entry in owner thread mutex list */ }; static void mutex_dump( struct object *obj, int verbose ); static int mutex_signaled( struct object *obj, struct wait_queue_entry *entry ); static void mutex_satisfied( struct object *obj, struct wait_queue_entry *entry ); static void mutex_destroy( struct object *obj ); static int mutex_signal( struct object *obj, unsigned int access ); static const struct object_ops mutex_ops = { sizeof(struct mutex), /* size */ &mutex_type, /* type */ mutex_dump, /* dump */ add_queue, /* add_queue */ remove_queue, /* remove_queue */ mutex_signaled, /* signaled */ mutex_satisfied, /* satisfied */ mutex_signal, /* signal */ no_get_fd, /* get_fd */ default_map_access, /* map_access */ default_get_sd, /* get_sd */ default_set_sd, /* set_sd */ default_get_full_name, /* get_full_name */ no_lookup_name, /* lookup_name */ directory_link_name, /* link_name */ default_unlink_name, /* unlink_name */ no_open_file, /* open_file */ no_kernel_obj_list, /* get_kernel_obj_list */ no_close_handle, /* close_handle */ mutex_destroy /* destroy */ }; /* grab a mutex for a given thread */ static void do_grab( struct mutex *mutex, struct thread *thread ) { assert( !mutex->count || (mutex->owner == thread) ); if (!mutex->count++) /* FIXME: avoid wrap-around */ { assert( !mutex->owner ); mutex->owner = thread; list_add_head( &thread->mutex_list, &mutex->entry ); } } /* release a mutex once the recursion count is 0 */ static void do_release( struct mutex *mutex ) { assert( !mutex->count ); /* remove the mutex from the thread list of owned mutexes */ list_remove( &mutex->entry ); mutex->owner = NULL; wake_up( &mutex->obj, 0 ); } static struct mutex *create_mutex( struct object *root, const struct unicode_str *name, unsigned int attr, int owned, const struct security_descriptor *sd ) { struct mutex *mutex; if ((mutex = create_named_object( root, &mutex_ops, name, attr, sd ))) { if (get_error() != STATUS_OBJECT_NAME_EXISTS) { /* initialize it if it didn't already exist */ mutex->count = 0; mutex->owner = NULL; mutex->abandoned = 0; if (owned) do_grab( mutex, current ); } } return mutex; } void abandon_mutexes( struct thread *thread ) { struct list *ptr; while ((ptr = list_head( &thread->mutex_list )) != NULL) { struct mutex *mutex = LIST_ENTRY( ptr, struct mutex, entry ); assert( mutex->owner == thread ); mutex->count = 0; mutex->abandoned = 1; do_release( mutex ); } } static void mutex_dump( struct object *obj, int verbose ) { struct mutex *mutex = (struct mutex *)obj; assert( obj->ops == &mutex_ops ); fprintf( stderr, "Mutex count=%u owner=%p\n", mutex->count, mutex->owner ); } static int mutex_signaled( struct object *obj, struct wait_queue_entry *entry ) { struct mutex *mutex = (struct mutex *)obj; assert( obj->ops == &mutex_ops ); return (!mutex->count || (mutex->owner == get_wait_queue_thread( entry ))); } static void mutex_satisfied( struct object *obj, struct wait_queue_entry *entry ) { struct mutex *mutex = (struct mutex *)obj; assert( obj->ops == &mutex_ops ); do_grab( mutex, get_wait_queue_thread( entry )); if (mutex->abandoned) make_wait_abandoned( entry ); mutex->abandoned = 0; } static int mutex_signal( struct object *obj, unsigned int access ) { struct mutex *mutex = (struct mutex *)obj; assert( obj->ops == &mutex_ops ); if (!(access & SYNCHRONIZE)) { set_error( STATUS_ACCESS_DENIED ); return 0; } if (!mutex->count || (mutex->owner != current)) { set_error( STATUS_MUTANT_NOT_OWNED ); return 0; } if (!--mutex->count) do_release( mutex ); return 1; } static void mutex_destroy( struct object *obj ) { struct mutex *mutex = (struct mutex *)obj; assert( obj->ops == &mutex_ops ); if (!mutex->count) return; mutex->count = 0; do_release( mutex ); } /* create a mutex */ DECL_HANDLER(create_mutex) { struct mutex *mutex; struct unicode_str name; struct object *root; const struct security_descriptor *sd; const struct object_attributes *objattr = get_req_object_attributes( &sd, &name, &root ); if (!objattr) return; if ((mutex = create_mutex( root, &name, objattr->attributes, req->owned, sd ))) { if (get_error() == STATUS_OBJECT_NAME_EXISTS) reply->handle = alloc_handle( current->process, mutex, req->access, objattr->attributes ); else reply->handle = alloc_handle_no_access_check( current->process, mutex, req->access, objattr->attributes ); release_object( mutex ); } if (root) release_object( root ); } /* open a handle to a mutex */ DECL_HANDLER(open_mutex) { struct unicode_str name = get_req_unicode_str(); reply->handle = open_object( current->process, req->rootdir, req->access, &mutex_ops, &name, req->attributes ); } /* release a mutex */ DECL_HANDLER(release_mutex) { struct mutex *mutex; if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle, 0, &mutex_ops ))) { if (!mutex->count || (mutex->owner != current)) set_error( STATUS_MUTANT_NOT_OWNED ); else { reply->prev_count = mutex->count; if (!--mutex->count) do_release( mutex ); } release_object( mutex ); } } /* return details about the mutex */ DECL_HANDLER(query_mutex) { struct mutex *mutex; if ((mutex = (struct mutex *)get_handle_obj( current->process, req->handle, MUTANT_QUERY_STATE, &mutex_ops ))) { reply->count = mutex->count; reply->owned = (mutex->owner == current); reply->abandoned = mutex->abandoned; release_object( mutex ); } }