lib/libelf/libelf_align.c

   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 LIBELF_VCSID("$Id$");
  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 }