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libelf_align.c revision 1.1 
      1 /*-
      2  * Copyright (c) 2006,2008 Joseph Koshy
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     24  * SUCH DAMAGE.
     25  */
     26 
     27 #include <sys/cdefs.h>
     28 
     29 #include <sys/types.h>
     30 
     31 #include <libelf.h>
     32 
     33 #include "_libelf.h"
     34 
     35 ELFTC_VCSID("Id: libelf_align.c 2225 2011-11-26 18:55:54Z jkoshy ");
     36 
     37 struct align {
     38 	int a32;
     39 	int a64;
     40 };
     41 
     42 #ifdef	__GNUC__
     43 #define	MALIGN(N)	{					\
     44 		.a32 = __alignof__(Elf32_##N),			\
     45 		.a64 = __alignof__(Elf64_##N)			\
     46 	}
     47 #define	MALIGN64(V)	  {					\
     48 		.a32 = 0,					\
     49 		.a64 = __alignof__(Elf64_##V)			\
     50 	}
     51 #define	MALIGN_WORD()	{					\
     52 		.a32 = __alignof__(int32_t),			\
     53 		.a64 = __alignof__(int64_t)			\
     54 	    }
     55 #else
     56 #error	Need the __alignof__ builtin.
     57 #endif
     58 #define	UNSUPPORTED()	{					\
     59 		.a32 = 0,					\
     60 		.a64 = 0					\
     61 	}
     62 
     63 static struct align malign[ELF_T_NUM] = {
     64 	[ELF_T_ADDR]	= MALIGN(Addr),
     65 	[ELF_T_BYTE]	= { .a32 = 1, .a64 = 1 },
     66 	[ELF_T_CAP]	= MALIGN(Cap),
     67 	[ELF_T_DYN]	= MALIGN(Dyn),
     68 	[ELF_T_EHDR]	= MALIGN(Ehdr),
     69 	[ELF_T_HALF]	= MALIGN(Half),
     70 	[ELF_T_LWORD]	= MALIGN(Lword),
     71 	[ELF_T_MOVE]	= MALIGN(Move),
     72 	[ELF_T_MOVEP] 	= UNSUPPORTED(),
     73 	[ELF_T_NOTE]	= MALIGN(Nhdr),
     74 	[ELF_T_OFF]	= MALIGN(Off),
     75 	[ELF_T_PHDR]	= MALIGN(Phdr),
     76 	[ELF_T_REL]	= MALIGN(Rel),
     77 	[ELF_T_RELA]	= MALIGN(Rela),
     78 	[ELF_T_SHDR]	= MALIGN(Shdr),
     79 	[ELF_T_SWORD]	= MALIGN(Sword),
     80 	[ELF_T_SXWORD]	= MALIGN64(Sxword),
     81 	[ELF_T_SYM]	= MALIGN(Sym),
     82 	[ELF_T_SYMINFO]	= MALIGN(Syminfo),
     83 	[ELF_T_VDEF]	= MALIGN(Verdef),
     84 	[ELF_T_VNEED]	= MALIGN(Verneed),
     85 	[ELF_T_WORD]	= MALIGN(Word),
     86 	[ELF_T_XWORD]	= MALIGN64(Xword),
     87 	[ELF_T_GNUHASH] = MALIGN_WORD()
     88 };
     89 
     90 int
     91 _libelf_malign(Elf_Type t, int elfclass)
     92 {
     93 	if (t >= ELF_T_NUM || (int) t < 0)
     94 		return (0);
     95 
     96 	return (elfclass == ELFCLASS32 ? malign[t].a32 :
     97 	    malign[t].a64);
     98 }
     99 
    100 #define	FALIGN(A32,A64)	{ .a32 = (A32), .a64 = (A64) }
    101 
    102 static struct align falign[ELF_T_NUM] = {
    103 	[ELF_T_ADDR]	= FALIGN(4,8),
    104 	[ELF_T_BYTE]	= FALIGN(1,1),
    105 	[ELF_T_CAP]	= FALIGN(4,8),
    106 	[ELF_T_DYN]	= FALIGN(4,8),
    107 	[ELF_T_EHDR]	= FALIGN(4,8),
    108 	[ELF_T_HALF]	= FALIGN(2,2),
    109 	[ELF_T_LWORD]	= FALIGN(8,8),
    110 	[ELF_T_MOVE]	= FALIGN(8,8),
    111 	[ELF_T_MOVEP] 	= UNSUPPORTED(),
    112 	[ELF_T_NOTE]	= FALIGN(4,4),
    113 	[ELF_T_OFF]	= FALIGN(4,8),
    114 	[ELF_T_PHDR]	= FALIGN(4,8),
    115 	[ELF_T_REL]	= FALIGN(4,8),
    116 	[ELF_T_RELA]	= FALIGN(4,8),
    117 	[ELF_T_SHDR]	= FALIGN(4,8),
    118 	[ELF_T_SWORD]	= FALIGN(4,4),
    119 	[ELF_T_SXWORD]	= FALIGN(0,8),
    120 	[ELF_T_SYM]	= FALIGN(4,8),
    121 	[ELF_T_SYMINFO]	= FALIGN(2,2),
    122 	[ELF_T_VDEF]	= FALIGN(4,4),
    123 	[ELF_T_VNEED]	= FALIGN(4,4),
    124 	[ELF_T_WORD]	= FALIGN(4,4),
    125 	[ELF_T_XWORD]	= FALIGN(0,8),
    126 	[ELF_T_GNUHASH] = FALIGN(4,8)
    127 };
    128 
    129 int
    130 _libelf_falign(Elf_Type t, int elfclass)
    131 {
    132 	if (t >= ELF_T_NUM || (int) t < 0)
    133 		return (0);
    134 
    135 	return (elfclass == ELFCLASS32 ? falign[t].a32 :
    136 	    falign[t].a64);
    137 }
    138