265 lines
9.5 KiB
C
265 lines
9.5 KiB
C
/*
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* Copyright (c) 2006-2008 Apple Inc. All rights reserved.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
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*
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* This file contains Original Code and/or Modifications of Original Code
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* as defined in and that are subject to the Apple Public Source License
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* Version 2.0 (the 'License'). You may not use this file except in
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* compliance with the License. The rights granted to you under the License
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* may not be used to create, or enable the creation or redistribution of,
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* unlawful or unlicensed copies of an Apple operating system, or to
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* circumvent, violate, or enable the circumvention or violation of, any
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* terms of an Apple operating system software license agreement.
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*
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* Please obtain a copy of the License at
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* http://www.opensource.apple.com/apsl/ and read it before using this file.
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*
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* The Original Code and all software distributed under the License are
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* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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* Please see the License for the specific language governing rights and
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* limitations under the License.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
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*
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*
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* Copyright (c) 1999 John D. Polstra
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#ifndef _SYS_LINKER_SET_H_
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#define _SYS_LINKER_SET_H_
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#include <sys/appleapiopts.h>
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#if !defined(KERNEL) || defined(__APPLE_API_PRIVATE)
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/*
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* The following macros are used to declare global sets of objects, which
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* are collected by the linker into a `linker set' as defined below.
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* For Mach-O, this is done by constructing a separate segment inside the
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* __DATA_CONST section for each set. The contents of this segment are an array
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* of pointers to the objects in the set.
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*
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* Note that due to limitations of the Mach-O format, there cannot
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* be more than 255 sections in a segment, so linker set usage should be
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* conserved. Set names may not exceed 16 characters.
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*/
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#include <sys/cdefs.h> /* __unsafe_indexable */
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#ifdef KERNEL
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# include <mach-o/loader.h>
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# include <libkern/kernel_mach_header.h>
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# define MACH_HEADER_TYPE kernel_mach_header_t
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# define GETSECTIONDATA_VARIANT getsectdatafromheader
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# define SECTDATA_SIZE_TYPE unsigned long
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# define MH_EXECUTE_HEADER &_mh_execute_header
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# define IMAGE_SLIDE_CORRECT 0
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#else
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# include <mach-o/ldsyms.h>
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# include <mach-o/getsect.h>
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# include <mach-o/loader.h>
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# include <mach-o/dyld.h>
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# include <crt_externs.h>
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# if __LP64__
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# define MACH_HEADER_TYPE struct mach_header_64
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# define GETSECTIONDATA_VARIANT getsectdatafromheader_64
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# define SECTDATA_SIZE_TYPE uint64_t
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# define MH_EXECUTE_HEADER _NSGetMachExecuteHeader()
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# else
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# define MACH_HEADER_TYPE struct mach_header
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# define GETSECTIONDATA_VARIANT getsectdatafromheader
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# define SECTDATA_SIZE_TYPE uint32_t
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# define MH_EXECUTE_HEADER _NSGetMachExecuteHeader()
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# endif
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#endif
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#if __LP64__
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# define LINKER_SET_ENTRY_PACKED
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# define LINKER_SET_SEGMENT __DATA_CONST
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# define LINKER_SET_SEGMENT_CSTR "__DATA_CONST"
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#else
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# define LINKER_SET_ENTRY_PACKED __attribute__((packed))
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# define LINKER_SET_SEGMENT __DATA
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# define LINKER_SET_SEGMENT_CSTR "__DATA"
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#endif
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/*
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* Private macros, not to be used outside this header file.
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*
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* The objective of this macro stack is to produce the following output,
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* given SET and SYM as arguments:
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*
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* void const * __set_SET_sym_SYM __attribute__((section("__DATA_CONST,SET"))) = & SYM
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*/
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/* Wrap entries in a type that can be blacklisted from KASAN */
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struct linker_set_entry {
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void *ptr;
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} LINKER_SET_ENTRY_PACKED;
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#ifdef __LS_VA_STRINGIFY__
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# undef __LS_VA_STRINGIFY__
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#endif
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#ifdef __LS_VA_STRCONCAT__
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# undef __LS_VA_STRCONCAT__
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#endif
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#define __LS_VA_STRINGIFY(_x ...) #_x
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#define __LS_VA_STRCONCAT(_x, _y) __LS_VA_STRINGIFY(_x,_y)
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#define __LINKER_MAKE_SET(_set, _sym) \
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/*__unused*/ /*static*/ const struct linker_set_entry /*const*/ __set_##_set##_sym_##_sym \
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__attribute__ ((section(__LS_VA_STRCONCAT(LINKER_SET_SEGMENT,_set)),used)) = { (void *)&_sym }
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/* the line above is very fragile - if your compiler breaks linker sets,
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* just play around with "static", "const", "used" etc. :-) */
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/*
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* Public macros.
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*/
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#define LINKER_SET_ENTRY(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
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/*
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* FreeBSD compatibility.
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*/
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#ifdef __APPLE_API_OBSOLETE
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# define TEXT_SET(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
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# define DATA_SET(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
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# define BSS_SET(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
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# define ABS_SET(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
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# define SET_ENTRY(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
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#endif /* __APPLE_API_OBSOLETE */
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/*
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* Extended linker set API.
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*
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* Since linker sets are per-object-file, and we may have multiple
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* object files, we need to be able to specify which object's set
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* to scan.
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*
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* The set itself is a contiguous array of pointers to the objects
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* within the set.
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*/
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/*
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* Public interface.
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*
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* void **LINKER_SET_OBJECT_BEGIN(_object, _set)
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* Preferred interface to linker_set_object_begin(), takes set name unquoted.
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* void **LINKER_SET_OBJECT_LIMIT(_object, _set)
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* Preferred interface to linker_set_object_begin(), takes set name unquoted.
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* LINKER_SET_OBJECT_FOREACH(_object, (set_member_type **)_pvar, _cast, _set)
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* Iterates over the members of _set within _object. Since the set contains
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* pointers to its elements, for a set of elements of type etyp, _pvar must
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* be (etyp **).
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* LINKER_SET_FOREACH((set_member_type **)_pvar, _cast, _set)
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*
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* Example of _cast: For the _pvar "struct sysctl_oid **oidpp", _cast would be
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* "struct sysctl_oid **"
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*
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*/
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#define LINKER_SET_OBJECT_BEGIN(_object, _set) __linker_set_object_begin(_object, _set)
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#define LINKER_SET_OBJECT_LIMIT(_object, _set) __linker_set_object_limit(_object, _set)
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#define LINKER_SET_OBJECT_FOREACH(_object, _pvar, _cast, _set) \
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for (_pvar = (_cast) LINKER_SET_OBJECT_BEGIN(_object, _set); \
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_pvar < (_cast) LINKER_SET_OBJECT_LIMIT(_object, _set); \
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_pvar++)
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#define LINKER_SET_OBJECT_ITEM(_object, _cast, _set, _i) \
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(((_cast)(LINKER_SET_OBJECT_BEGIN(_object, _set)))[_i])
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#define LINKER_SET_FOREACH(_pvar, _cast, _set) \
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LINKER_SET_OBJECT_FOREACH((MACH_HEADER_TYPE *)MH_EXECUTE_HEADER, _pvar, _cast, _set)
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/*
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* Implementation.
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*
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* void **__linker_set_object_begin(_header, _set)
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* Returns a pointer to the first pointer in the linker set.
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* void **__linker_set_object_limi(_header, _set)
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* Returns an upper bound to the linker set (base + size).
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*/
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static __inline intptr_t
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__linker_get_slide(struct mach_header *_header)
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{
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#ifndef KERNEL
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/*
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* Gross.
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*
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* We cannot get the image slide directly from the header, so we need to
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* determine the image's index and ask for the slide of that index.
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*/
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uint32_t i = 0;
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for (i = 0; i < _dyld_image_count(); i++) {
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const struct mach_header *hdr = _dyld_get_image_header(i);
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if (_header == hdr) {
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return _dyld_get_image_vmaddr_slide(i);
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}
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}
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return 0;
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#else
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(void)_header;
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return 0;
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#endif
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}
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static __inline void *__unsafe_indexable *__unsafe_indexable
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__linker_set_object_begin(MACH_HEADER_TYPE *_header, const char *_set)
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__attribute__((__const__));
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static __inline void *__unsafe_indexable *__unsafe_indexable
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__linker_set_object_begin(MACH_HEADER_TYPE *_header, const char *_set)
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{
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char *_set_begin;
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SECTDATA_SIZE_TYPE _size;
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_set_begin = (char *)GETSECTIONDATA_VARIANT(_header, LINKER_SET_SEGMENT_CSTR, _set, &_size);
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_set_begin += __linker_get_slide((struct mach_header *)_header);
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return (void **)(uintptr_t)_set_begin;
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}
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static __inline void *__unsafe_indexable *__unsafe_indexable
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__linker_set_object_limit(MACH_HEADER_TYPE *_header, const char *_set)
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__attribute__((__const__));
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static __inline void *__unsafe_indexable *__unsafe_indexable
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__linker_set_object_limit(MACH_HEADER_TYPE *_header, const char *_set)
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{
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char *_set_begin;
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SECTDATA_SIZE_TYPE _size;
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_set_begin = (char *)GETSECTIONDATA_VARIANT(_header, LINKER_SET_SEGMENT_CSTR, _set, &_size);
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_set_begin += __linker_get_slide((struct mach_header *)_header);
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return (void **) ((uintptr_t) _set_begin + _size);
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}
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#endif /* !KERNEL || __APPLE_API_PRIVATE */
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#endif /* _SYS_LINKER_SET_H_ */
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