osfmk/kern/copyout_shim.c

   1 /*
   2  * Copyright (c) 2017 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <mach/mach_types.h>
  29 #include <mach/vm_param.h>
  30 #include <string.h>
  31 #include <pexpert/pexpert.h>
  32 #include <kern/copyout_shim.h>
  33
  34 #if (DEVELOPMENT || DEBUG)
  35 #define UNUSED_IN_RELEASE(x)
  36 #else
  37 //supress compiler warnings about unused variables
  38 #define UNUSED_IN_RELEASE(x) (void)(x)
  39 #endif /* (DEVELOPMENT || DEBUG) */
  40
  41
  42 #if (DEVELOPMENT || DEBUG)
  43 copyout_shim_fn_t copyout_shim_fn = NULL;
  44 unsigned co_src_flags = 0;
  45 #endif
  46
  47 kern_return_t
  48 register_copyout_shim(void (*fn)(const void *, user_addr_t, vm_size_t, unsigned co_src), unsigned types)
  49 {
  50 #if (DEVELOPMENT || DEBUG)
  51         int copyout_shim_enabled = 0;
  52
  53         if (!fn) {
  54                 /* unregistration is always allowed */
  55                 copyout_shim_fn = NULL;
  56                 return KERN_SUCCESS;
  57         }
  58
  59         if (copyout_shim_fn) {
  60                 //need to unregister first before registering a new one.
  61                 return KERN_FAILURE;
  62         }
  63
  64         if (!PE_parse_boot_argn("enable_copyout_shim", &copyout_shim_enabled, sizeof(copyout_shim_enabled)) || !copyout_shim_enabled) {
  65                 return KERN_FAILURE;
  66         }
  67
  68
  69         co_src_flags = types;
  70         copyout_shim_fn = fn;
  71         return KERN_SUCCESS;
  72 #else
  73         UNUSED_IN_RELEASE(fn);
  74         UNUSED_IN_RELEASE(types);
  75         return KERN_FAILURE;
  76 #endif
  77 }
  78
  79 void *
  80 cos_kernel_unslide(const void *ptr)
  81 {
  82 #if (DEVELOPMENT || DEBUG)
  83         return (void *)(VM_KERNEL_UNSLIDE(ptr));
  84 #else
  85         UNUSED_IN_RELEASE(ptr);
  86         return NULL;
  87 #endif
  88 }
  89
  90 void *
  91 cos_kernel_reslide(const void *ptr)
  92 {
  93 #if (DEVELOPMENT || DEBUG)
  94         return (void *)(VM_KERNEL_SLIDE(ptr));
  95 #else
  96         UNUSED_IN_RELEASE(ptr);
  97         return NULL;
  98 #endif
  99 }