xnu-4903.270.47.tar.gz

[apple/xnu.git] / libkern / kmod / c_start.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 *   Subtle combination of files and libraries make up the C++ runtime system for kernel modules.  We are dependant on the KernelModule kmod.make and CreateKModInfo.perl scripts to be exactly instep with both this library module and the libkmod module as well.
 *
 *   If you do any maintenance on any of the following files make sure great care is taken to keep them in Sync.
 *   KernelModule.bproj/kmod.make
 *   KernelModule.bproj/CreateKModInfo.perl
 *   KernelModule.bproj/kmodc++/pure.c
 *   KernelModule.bproj/kmodc++/cplus_start.c
 *   KernelModule.bproj/kmodc++/cplus_start.c
 *   KernelModule.bproj/kmodc/c_start.c
 *   KernelModule.bproj/kmodc/c_stop.c
 *
 *   The trick is that the linkline links all of the developers modules.  If any static constructors are used .constructors_used will be left as an undefined symbol.  This symbol is exported by the cplus_start.c routine which automatically brings in the appropriate C++ _start routine.  However the actual _start symbol is only required by the kmod_info structure that is created and initialized by the CreateKModInfo.perl script.  If no C++ was used the _start will be an undefined symbol that is finally satisfied by the c_start module in the kmod library.
 *
 *   The linkline must look like this.
 *.o -lkmodc++ kmod_info.o -lkmod
 */
#include <mach/mach_types.h>
#include <libkern/OSKextLib.h>

// These global symbols will be defined by CreateInfo script's info.c file.
extern kmod_start_func_t *_realmain;
extern kmod_info_t KMOD_INFO_NAME;

/*********************************************************************
*********************************************************************/
__private_extern__ kern_return_t
_start(kmod_info_t *ki, void *data)
{
	if (_realmain) {
		return (*_realmain)(ki, data);
	} else {
		return KERN_SUCCESS;
	}
}

/*********************************************************************
*********************************************************************/
__private_extern__ const char *
OSKextGetCurrentIdentifier(void)
{
	return KMOD_INFO_NAME.name;
}

/*********************************************************************
*********************************************************************/
__private_extern__ const char *
OSKextGetCurrentVersionString(void)
{
	return KMOD_INFO_NAME.version;
}

/*********************************************************************
*********************************************************************/
__private_extern__ OSKextLoadTag
OSKextGetCurrentLoadTag(void)
{
	return (OSKextLoadTag)KMOD_INFO_NAME.id;
}