darling-Libc/os/linker_set.h
2023-04-21 10:18:52 -07:00

264 lines
9.4 KiB
C

/*
* Copyright (c) 2006-2008 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@
*
*
* Copyright (c) 1999 John D. Polstra
* 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 AUTHOR 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 AUTHOR 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.
*
*/
#ifndef _SYS_LINKER_SET_H_
#define _SYS_LINKER_SET_H_
#include <sys/appleapiopts.h>
#if !defined(KERNEL) || defined(__APPLE_API_PRIVATE)
/*
* The following macros are used to declare global sets of objects, which
* are collected by the linker into a `linker set' as defined below.
* For Mach-O, this is done by constructing a separate segment inside the
* __DATA_CONST section for each set. The contents of this segment are an array
* of pointers to the objects in the set.
*
* Note that due to limitations of the Mach-O format, there cannot
* be more than 255 sections in a segment, so linker set usage should be
* conserved. Set names may not exceed 16 characters.
*/
#ifdef KERNEL
# include <mach-o/loader.h>
# include <libkern/kernel_mach_header.h>
# define MACH_HEADER_TYPE kernel_mach_header_t
# define GETSECTIONDATA_VARIANT getsectdatafromheader
# define SECTDATA_SIZE_TYPE unsigned long
# define MH_EXECUTE_HEADER &_mh_execute_header
# define IMAGE_SLIDE_CORRECT 0
#else
# include <mach-o/ldsyms.h>
# include <mach-o/getsect.h>
# include <mach-o/loader.h>
# include <mach-o/dyld.h>
# include <crt_externs.h>
# if __LP64__
# define MACH_HEADER_TYPE struct mach_header_64
# define GETSECTIONDATA_VARIANT getsectdatafromheader_64
# define SECTDATA_SIZE_TYPE uint64_t
# define MH_EXECUTE_HEADER _NSGetMachExecuteHeader()
# else
# define MACH_HEADER_TYPE struct mach_header
# define GETSECTIONDATA_VARIANT getsectdatafromheader
# define SECTDATA_SIZE_TYPE uint32_t
# define MH_EXECUTE_HEADER _NSGetMachExecuteHeader()
# endif
#endif
#if __LP64__ && !(__x86_64__ || __i386__)
# define LINKER_SET_ENTRY_PACKED
# define LINKER_SET_SEGMENT __DATA_CONST
# define LINKER_SET_SEGMENT_CSTR "__DATA_CONST"
#else
# define LINKER_SET_ENTRY_PACKED __attribute__((packed))
# define LINKER_SET_SEGMENT __DATA
# define LINKER_SET_SEGMENT_CSTR "__DATA"
#endif
/*
* Private macros, not to be used outside this header file.
*
* The objective of this macro stack is to produce the following output,
* given SET and SYM as arguments:
*
* void const * __set_SET_sym_SYM __attribute__((section("__DATA_CONST,SET"))) = & SYM
*/
/* Wrap entries in a type that can be blacklisted from KASAN */
struct linker_set_entry {
void *ptr;
} LINKER_SET_ENTRY_PACKED;
#ifdef __LS_VA_STRINGIFY__
# undef __LS_VA_STRINGIFY__
#endif
#ifdef __LS_VA_STRCONCAT__
# undef __LS_VA_STRCONCAT__
#endif
#define __LS_VA_STRINGIFY(_x ...) #_x
#define __LS_VA_STRCONCAT(_x, _y) __LS_VA_STRINGIFY(_x,_y)
#define __LINKER_MAKE_SET(_set, _sym) \
/*__unused*/ /*static*/ const struct linker_set_entry /*const*/ __set_##_set##_sym_##_sym \
__attribute__ ((section(__LS_VA_STRCONCAT(LINKER_SET_SEGMENT,_set)),used)) = { (void *)&_sym }
/* the line above is very fragile - if your compiler breaks linker sets,
* just play around with "static", "const", "used" etc. :-) */
/*
* Public macros.
*/
#define LINKER_SET_ENTRY(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
/*
* FreeBSD compatibility.
*/
#ifdef __APPLE_API_OBSOLETE
# define TEXT_SET(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
# define DATA_SET(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
# define BSS_SET(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
# define ABS_SET(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
# define SET_ENTRY(_set, _sym) __LINKER_MAKE_SET(_set, _sym)
#endif /* __APPLE_API_OBSOLETE */
/*
* Extended linker set API.
*
* Since linker sets are per-object-file, and we may have multiple
* object files, we need to be able to specify which object's set
* to scan.
*
* The set itself is a contiguous array of pointers to the objects
* within the set.
*/
/*
* Public interface.
*
* void **LINKER_SET_OBJECT_BEGIN(_object, _set)
* Preferred interface to linker_set_object_begin(), takes set name unquoted.
* void **LINKER_SET_OBJECT_LIMIT(_object, _set)
* Preferred interface to linker_set_object_begin(), takes set name unquoted.
* LINKER_SET_OBJECT_FOREACH(_object, (set_member_type **)_pvar, _cast, _set)
* Iterates over the members of _set within _object. Since the set contains
* pointers to its elements, for a set of elements of type etyp, _pvar must
* be (etyp **).
* LINKER_SET_FOREACH((set_member_type **)_pvar, _cast, _set)
*
* Example of _cast: For the _pvar "struct sysctl_oid **oidpp", _cast would be
* "struct sysctl_oid **"
*
*/
#define LINKER_SET_OBJECT_BEGIN(_object, _set) __linker_set_object_begin(_object, _set)
#define LINKER_SET_OBJECT_LIMIT(_object, _set) __linker_set_object_limit(_object, _set)
#define LINKER_SET_OBJECT_FOREACH(_object, _pvar, _cast, _set) \
for (_pvar = (_cast) LINKER_SET_OBJECT_BEGIN(_object, _set); \
_pvar < (_cast) LINKER_SET_OBJECT_LIMIT(_object, _set); \
_pvar++)
#define LINKER_SET_OBJECT_ITEM(_object, _cast, _set, _i) \
(((_cast)(LINKER_SET_OBJECT_BEGIN(_object, _set)))[_i])
#define LINKER_SET_FOREACH(_pvar, _cast, _set) \
LINKER_SET_OBJECT_FOREACH((MACH_HEADER_TYPE *)MH_EXECUTE_HEADER, _pvar, _cast, _set)
/*
* Implementation.
*
* void **__linker_set_object_begin(_header, _set)
* Returns a pointer to the first pointer in the linker set.
* void **__linker_set_object_limi(_header, _set)
* Returns an upper bound to the linker set (base + size).
*/
static __inline intptr_t
__linker_get_slide(struct mach_header *_header)
{
#ifndef KERNEL
/*
* Gross.
*
* We cannot get the image slide directly from the header, so we need to
* determine the image's index and ask for the slide of that index.
*/
uint32_t i = 0;
for (i = 0; i < _dyld_image_count(); i++) {
const struct mach_header *hdr = _dyld_get_image_header(i);
if (_header == hdr) {
return _dyld_get_image_vmaddr_slide(i);
}
}
return 0;
#else
(void)_header;
return 0;
#endif
}
static __inline void **
__linker_set_object_begin(MACH_HEADER_TYPE *_header, const char *_set)
__attribute__((__const__));
static __inline void **
__linker_set_object_begin(MACH_HEADER_TYPE *_header, const char *_set)
{
char *_set_begin;
SECTDATA_SIZE_TYPE _size;
_set_begin = (char *)GETSECTIONDATA_VARIANT(_header, LINKER_SET_SEGMENT_CSTR, _set, &_size);
_set_begin += __linker_get_slide((struct mach_header *)_header);
return (void **)(uintptr_t)_set_begin;
}
static __inline void **
__linker_set_object_limit(MACH_HEADER_TYPE *_header, const char *_set)
__attribute__((__const__));
static __inline void **
__linker_set_object_limit(MACH_HEADER_TYPE *_header, const char *_set)
{
char *_set_begin;
SECTDATA_SIZE_TYPE _size;
_set_begin = (char *)GETSECTIONDATA_VARIANT(_header, LINKER_SET_SEGMENT_CSTR, _set, &_size);
_set_begin += __linker_get_slide((struct mach_header *)_header);
return (void **) ((uintptr_t) _set_begin + _size);
}
#endif /* !KERNEL || __APPLE_API_PRIVATE */
#endif /* _SYS_LINKER_SET_H_ */