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libelf_align.c revision 1.8 
      1 /*	$NetBSD: libelf_align.c,v 1.8 2025/12/26 07:07:35 mrg Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2006,2008 Joseph Koshy
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #if HAVE_NBTOOL_CONFIG_H
     30 # include "nbtool_config.h"
     31 #endif
     32 
     33 #include <sys/cdefs.h>
     34 
     35 #include <sys/types.h>
     36 
     37 #include <libelf.h>
     38 
     39 #include "_libelf.h"
     40 
     41 ELFTC_VCSID("Id: libelf_align.c 4074 2025-01-07 15:34:21Z jkoshy");
     42 
     43 __RCSID("$NetBSD: libelf_align.c,v 1.8 2025/12/26 07:07:35 mrg Exp $");
     44 
     45 struct align {
     46 	unsigned int a32;
     47 	unsigned int a64;
     48 };
     49 
     50 #if defined(__GNUC__) || defined(__lint__)
     51 #define	MALIGN(N)	{					\
     52 		.a32 = __alignof__(Elf32_##N),			\
     53 		.a64 = __alignof__(Elf64_##N)			\
     54 	}
     55 #define	MALIGN64(V)	  {					\
     56 		.a32 = 0,					\
     57 		.a64 = __alignof__(Elf64_##V)			\
     58 	}
     59 #define	MALIGN_WORD()	{					\
     60 		.a32 = __alignof__(int32_t),			\
     61 		.a64 = __alignof__(int64_t)			\
     62 	    }
     63 #elif defined(__lint__)
     64 #define MALIGN(N)	{ .a32 = 0, .a64 = 0 }
     65 #define MALIGN64(N)	{ .a32 = 0, .a64 = 0 }
     66 #define MALIGN_WORD(N)	{ .a32 = 0, .a64 = 0 }
     67 #else
     68 #error	Need the __alignof__ builtin.
     69 #endif
     70 #define	UNSUPPORTED()	{					\
     71 		.a32 = 0,					\
     72 		.a64 = 0					\
     73 	}
     74 
     75 static struct align malign[ELF_T_NUM] = {
     76 	[ELF_T_ADDR]	= MALIGN(Addr),
     77 	[ELF_T_BYTE]	= { .a32 = 1, .a64 = 1 },
     78 	[ELF_T_CAP]	= MALIGN(Cap),
     79 	[ELF_T_DYN]	= MALIGN(Dyn),
     80 	[ELF_T_EHDR]	= MALIGN(Ehdr),
     81 	[ELF_T_HALF]	= MALIGN(Half),
     82 	[ELF_T_LWORD]	= MALIGN(Lword),
     83 	[ELF_T_MOVE]	= MALIGN(Move),
     84 	[ELF_T_MOVEP] 	= UNSUPPORTED(),
     85 	[ELF_T_NOTE]	= MALIGN(Nhdr),
     86 	[ELF_T_OFF]	= MALIGN(Off),
     87 	[ELF_T_PHDR]	= MALIGN(Phdr),
     88 	[ELF_T_REL]	= MALIGN(Rel),
     89 	[ELF_T_RELA]	= MALIGN(Rela),
     90 	[ELF_T_SHDR]	= MALIGN(Shdr),
     91 	[ELF_T_SWORD]	= MALIGN(Sword),
     92 	[ELF_T_SXWORD]	= MALIGN64(Sxword),
     93 	[ELF_T_SYM]	= MALIGN(Sym),
     94 	[ELF_T_SYMINFO]	= MALIGN(Syminfo),
     95 	[ELF_T_VDEF]	= MALIGN(Verdef),
     96 	[ELF_T_VNEED]	= MALIGN(Verneed),
     97 	[ELF_T_WORD]	= MALIGN(Word),
     98 	[ELF_T_XWORD]	= MALIGN64(Xword),
     99 	[ELF_T_GNUHASH] = MALIGN_WORD()
    100 };
    101 
    102 unsigned int
    103 _libelf_malign(Elf_Type t, unsigned int elfclass)
    104 {
    105 	if (t >= ELF_T_NUM || (int) t < 0)
    106 		return (0);
    107 
    108 	return (elfclass == ELFCLASS32 ? malign[t].a32 :
    109 	    malign[t].a64);
    110 }
    111 
    112 #define	FALIGN(A32,A64)	{ .a32 = (A32), .a64 = (A64) }
    113 
    114 static struct align falign[ELF_T_NUM] = {
    115 	[ELF_T_ADDR]	= FALIGN(4,8),
    116 	[ELF_T_BYTE]	= FALIGN(1,1),
    117 	[ELF_T_CAP]	= FALIGN(4,8),
    118 	[ELF_T_DYN]	= FALIGN(4,8),
    119 	[ELF_T_EHDR]	= FALIGN(4,8),
    120 	[ELF_T_HALF]	= FALIGN(2,2),
    121 	[ELF_T_LWORD]	= FALIGN(8,8),
    122 	[ELF_T_MOVE]	= FALIGN(8,8),
    123 	[ELF_T_MOVEP] 	= UNSUPPORTED(),
    124 	[ELF_T_NOTE]	= FALIGN(4,4),
    125 	[ELF_T_OFF]	= FALIGN(4,8),
    126 	[ELF_T_PHDR]	= FALIGN(4,8),
    127 	[ELF_T_REL]	= FALIGN(4,8),
    128 	[ELF_T_RELA]	= FALIGN(4,8),
    129 	[ELF_T_SHDR]	= FALIGN(4,8),
    130 	[ELF_T_SWORD]	= FALIGN(4,4),
    131 	[ELF_T_SXWORD]	= FALIGN(0,8),
    132 	[ELF_T_SYM]	= FALIGN(4,8),
    133 	[ELF_T_SYMINFO]	= FALIGN(2,2),
    134 	[ELF_T_VDEF]	= FALIGN(4,4),
    135 	[ELF_T_VNEED]	= FALIGN(4,4),
    136 	[ELF_T_WORD]	= FALIGN(4,4),
    137 	[ELF_T_XWORD]	= FALIGN(0,8),
    138 	[ELF_T_GNUHASH] = FALIGN(4,8)
    139 };
    140 
    141 unsigned int
    142 _libelf_falign(Elf_Type t, unsigned int elfclass)
    143 {
    144 	if (t >= ELF_T_NUM || (int) t < 0)
    145 		return (0);
    146 
    147 	return (elfclass == ELFCLASS32 ? falign[t].a32 :
    148 	    falign[t].a64);
    149 }
    150