xnu-4570.71.2.tar.gz

[apple/xnu.git] / osfmk / kern / copyout_shim.c

/*
 * Copyright (c) 2017 Apple 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@
 */
#include <mach/mach_types.h>
#include <mach/vm_param.h>
#include <string.h>
#include <pexpert/pexpert.h>
#include <kern/copyout_shim.h>

#if (DEVELOPMENT || DEBUG)
#define UNUSED_IN_RELEASE(x)
#else
//supress compiler warnings about unused variables
#define UNUSED_IN_RELEASE(x) (void)(x)
#endif /* (DEVELOPMENT || DEBUG) */


#if (DEVELOPMENT || DEBUG)
copyout_shim_fn_t copyout_shim_fn=NULL;
unsigned co_src_flags=0;
#endif

kern_return_t register_copyout_shim(void (*fn)(const void *,user_addr_t,vm_size_t,unsigned co_src),unsigned types)
{
#if (DEVELOPMENT || DEBUG)
    int copyout_shim_enabled=0;
    
    if(!fn)
    {
        /* unregistration is always allowed */
        copyout_shim_fn=NULL;
        return KERN_SUCCESS;
    }
    
    if(copyout_shim_fn)
    {
        //need to unregister first before registering a new one.
        return KERN_FAILURE;
    }
    
    if(!PE_parse_boot_argn("enable_copyout_shim",&copyout_shim_enabled,sizeof(copyout_shim_enabled)) || !copyout_shim_enabled)
    {
        return KERN_FAILURE;
    }
    

    co_src_flags=types;
    copyout_shim_fn=fn;
    return KERN_SUCCESS;
#else
    UNUSED_IN_RELEASE(fn);
    UNUSED_IN_RELEASE(types);
    return KERN_FAILURE;
#endif
}

void *cos_kernel_unslide(const void *ptr)
{
#if (DEVELOPMENT || DEBUG)
    return (void *)(VM_KERNEL_UNSLIDE(ptr));
#else
    UNUSED_IN_RELEASE(ptr);
    return NULL;
#endif
}

void *cos_kernel_reslide(const void *ptr)
{
#if (DEVELOPMENT || DEBUG)
    return (void *)(VM_KERNEL_SLIDE(ptr));
#else
    UNUSED_IN_RELEASE(ptr);
    return NULL;
#endif
}