/*      $NetBSD: db_syncobj.c,v 1.3 2023/10/15 10:27:25 riastradh Exp $ */

/*-
* Copyright (c) 2023 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#define __MUTEX_PRIVATE
#define __RWLOCK_PRIVATE

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: db_syncobj.c,v 1.3 2023/10/15 10:27:25 riastradh Exp $");

#include <sys/types.h>

#include <sys/mutex.h>
#include <sys/null.h>
#include <sys/rwlock.h>
#include <sys/syncobj.h>

#include <ddb/ddb.h>

struct lwp *
db_syncobj_owner(const struct syncobj *sobj, wchan_t wchan)
{
       db_expr_t mutex_syncobj_;
       db_expr_t rw_syncobj_;

       if (db_value_of_name("mutex_syncobj", &mutex_syncobj_) &&
           (db_expr_t)(uintptr_t)sobj == mutex_syncobj_) {
               volatile const struct kmutex *mtx = wchan;
               uintptr_t owner;

               db_read_bytes((db_addr_t)&mtx->mtx_owner, sizeof(owner),
                   (char *)&owner);
               return (struct lwp *)(owner & MUTEX_THREAD);

       } else if (db_value_of_name("rw_syncobj", &rw_syncobj_) &&
           (db_expr_t)(uintptr_t)sobj == rw_syncobj_) {
               volatile const struct krwlock *rw = wchan;
               uintptr_t owner;

               db_read_bytes((db_addr_t)&rw->rw_owner, sizeof(owner),
                   (char *)&owner);
               if (owner & RW_WRITE_LOCKED)
                       return (struct lwp *)(owner & RW_THREAD);
               return NULL;

       } else {
               return NULL;
       }
}