libelf/gelf_xlate.c

   1 /* Transformation functions for ELF data types.
   2    Copyright (C) 1998,1999,2000,2002,2004,2005,2006,2007 Red Hat, Inc.
   3    This file is part of elfutils.
   4    Written by Ulrich Drepper <drepper@redhat.com>, 1998.
   5
   6    This file is free software; you can redistribute it and/or modify
   7    it under the terms of either
   8
   9      * the GNU Lesser General Public License as published by the Free
  10        Software Foundation; either version 3 of the License, or (at
  11        your option) any later version
  12
  13    or
  14
  15      * the GNU General Public License as published by the Free
  16        Software Foundation; either version 2 of the License, or (at
  17        your option) any later version
  18
  19    or both in parallel, as here.
  20
  21    elfutils is distributed in the hope that it will be useful, but
  22    WITHOUT ANY WARRANTY; without even the implied warranty of
  23    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  24    General Public License for more details.
  25
  26    You should have received copies of the GNU General Public License and
  27    the GNU Lesser General Public License along with this program.  If
  28    not, see <http://www.gnu.org/licenses/>.  */
  29
  30 #ifdef HAVE_CONFIG_H
  31 # include <config.h>
  32 #endif
  33
  34 #include <byteswap.h>
  35 #include <stdint.h>
  36 #include <string.h>
  37 #include <stdlib.h>
  38
  39 #include "libelfP.h"
  40
  41 #ifndef LIBELFBITS
  42 # define LIBELFBITS     32
  43 #endif
  44
  45
  46 /* Well, what shall I say.  Nothing to do here.  */
  47 #define elf_cvt_Byte(dest, src, n) \
  48   (__builtin_constant_p (n) && (n) == 1                                       \
  49    ? (void) (*((char *) (dest)) = *((char *) (src)))                          \
  50    : Elf32_cvt_Byte (dest, src, n))
  51 static void
  52 (elf_cvt_Byte) (void *dest, const void *src, size_t n,
  53                 int encode __attribute__ ((unused)))
  54 {
  55   memmove (dest, src, n);
  56 }
  57
  58
  59 /* We'll optimize the definition of the conversion functions here a
  60    bit.  We need only functions for 16, 32, and 64 bits.  The
  61    functions referenced in the table will be aliases for one of these
  62    functions.  Which one is decided by the ELFxx_FSZ_type.  */
  63
  64 #if ALLOW_UNALIGNED
  65
  66 #define FETCH(Bits, ptr)        (*(const uint##Bits##_t *) ptr)
  67 #define STORE(Bits, ptr, val)   (*(uint##Bits##_t *) ptr = val)
  68
  69 #else
  70
  71 union unaligned
  72   {
  73     uint16_t u16;
  74     uint32_t u32;
  75     uint64_t u64;
  76   } __attribute__ ((packed));
  77
  78 #define FETCH(Bits, ptr)        (((const union unaligned *) ptr)->u##Bits)
  79 #define STORE(Bits, ptr, val)   (((union unaligned *) ptr)->u##Bits = val)
  80
  81 #endif
  82
  83 /* Now define the conversion functions for the basic types.  We use here
  84    the fact that file and memory types are the same and that we have the
  85    ELFxx_FSZ_* macros.
  86
  87    At the same time we define inline functions which we will use to
  88    convert the complex types.  */
  89 #define FUNDAMENTAL(NAME, Name, Bits) \
  90   INLINE2 (ELFW2(Bits,FSZ_##NAME), ElfW2(Bits,cvt_##Name), ElfW2(Bits,Name))
  91 #define INLINE2(Bytes, FName, TName) \
  92   INLINE3 (Bytes, FName, TName)
  93 #define INLINE3(Bytes, FName, TName)                                          \
  94   static inline void FName##1 (void *dest, const void *ptr)                   \
  95   {                                                                           \
  96     switch (Bytes)                                                            \
  97       {                                                                       \
  98       case 2: STORE (16, dest, bswap_16 (FETCH (16, ptr))); break;            \
  99       case 4: STORE (32, dest, bswap_32 (FETCH (32, ptr))); break;            \
 100       case 8: STORE (64, dest, bswap_64 (FETCH (64, ptr))); break;            \
 101       default:                                                                \
 102         abort ();                                                             \
 103       }                                                                       \
 104   }                                                                           \
 105                                                                               \
 106   static void FName (void *dest, const void *ptr, size_t len,                 \
 107                      int encode __attribute__ ((unused)))                     \
 108   {                                                                           \
 109     size_t n = len / sizeof (TName);                                          \
 110     if (dest < ptr)                                                           \
 111       while (n-- > 0)                                                         \
 112         {                                                                     \
 113           FName##1 (dest, ptr);                                               \
 114           dest += Bytes;                                                      \
 115           ptr += Bytes;                                                       \
 116         }                                                                     \
 117     else                                                                      \
 118       {                                                                       \
 119         dest += len;                                                          \
 120         ptr += len;                                                           \
 121         while (n-- > 0)                                                       \
 122           {                                                                   \
 123             ptr -= Bytes;                                                     \
 124             dest -= Bytes;                                                    \
 125             FName##1 (dest, ptr);                                             \
 126           }                                                                   \
 127       }                                                                       \
 128   }
 129
 130
 131 /* Now the tricky part: define the transformation functions for the
 132    complex types.  We will use the definitions of the types in
 133    abstract.h.  */
 134 #define START(Bits, Name, EName) \
 135   static void                                                                 \
 136   ElfW2 (Bits, cvt_##Name) (void *dest, const void *src, size_t len,          \
 137                             int encode __attribute__ ((unused)))              \
 138   { ElfW2(Bits, Name) *tdest = (ElfW2(Bits, Name) *) dest;                    \
 139     ElfW2(Bits, Name) *tsrc = (ElfW2(Bits, Name) *) src;                      \
 140     size_t n;                                                                 \
 141     for (n = len / sizeof (ElfW2(Bits, Name)); n > 0; ++tdest, ++tsrc, --n) {
 142 #define END(Bits, Name) } }
 143 #define TYPE_EXTRA(Code)
 144 #define TYPE_XLATE(Code) Code
 145 #define TYPE_NAME(Type, Name) TYPE_NAME2 (Type, Name)
 146 #define TYPE_NAME2(Type, Name) Type##1 (&tdest->Name, &tsrc->Name);
 147 #define TYPE(Name, Bits) TYPE2 (Name, Bits)
 148 #define TYPE2(Name, Bits) TYPE3 (Name##Bits)
 149 #define TYPE3(Name) Name (cvt_)
 150
 151 /* Signal that we are generating conversion functions.  */
 152 #define GENERATE_CONVERSION
 153
 154 /* First generate the 32-bit conversion functions.  */
 155 #define LIBELFBITS 32
 156 #include "gelf_xlate.h"
 157
 158 /* Now generate the 64-bit conversion functions.  */
 159 #define LIBELFBITS 64
 160 #include "gelf_xlate.h"
 161
 162
 163 /* We have a few functions which we must create by hand since the sections
 164    do not contain records of only one type.  */
 165 #include "version_xlate.h"
 166 #include "gnuhash_xlate.h"
 167 #include "note_xlate.h"
 168
 169
 170 /* Now the externally visible table with the function pointers.  */
 171 const xfct_t __elf_xfctstom[EV_NUM - 1][EV_NUM - 1][ELFCLASSNUM - 1][ELF_T_NUM] =
 172 {
 173   [EV_CURRENT - 1] = {
 174     [EV_CURRENT - 1] = {
 175       [ELFCLASS32 - 1] = {
 176 #define define_xfcts(Bits) \
 177         [ELF_T_BYTE]    = elf_cvt_Byte,                                       \
 178         [ELF_T_ADDR]    = ElfW2(Bits, cvt_Addr),                              \
 179         [ELF_T_DYN]     = ElfW2(Bits, cvt_Dyn),                               \
 180         [ELF_T_EHDR]    = ElfW2(Bits, cvt_Ehdr),                              \
 181         [ELF_T_HALF]    = ElfW2(Bits, cvt_Half),                              \
 182         [ELF_T_OFF]     = ElfW2(Bits, cvt_Off),                               \
 183         [ELF_T_PHDR]    = ElfW2(Bits, cvt_Phdr),                              \
 184         [ELF_T_RELA]    = ElfW2(Bits, cvt_Rela),                              \
 185         [ELF_T_REL]     = ElfW2(Bits, cvt_Rel),                               \
 186         [ELF_T_SHDR]    = ElfW2(Bits, cvt_Shdr),                              \
 187         [ELF_T_SWORD]   = ElfW2(Bits, cvt_Sword),                             \
 188         [ELF_T_SYM]     = ElfW2(Bits, cvt_Sym),                               \
 189         [ELF_T_WORD]    = ElfW2(Bits, cvt_Word),                              \
 190         [ELF_T_XWORD]   = ElfW2(Bits, cvt_Xword),                             \
 191         [ELF_T_SXWORD]  = ElfW2(Bits, cvt_Sxword),                            \
 192         [ELF_T_VDEF]    = elf_cvt_Verdef,                                     \
 193         [ELF_T_VDAUX]   = elf_cvt_Verdef,                                     \
 194         [ELF_T_VNEED]   = elf_cvt_Verneed,                                    \
 195         [ELF_T_VNAUX]   = elf_cvt_Verneed,                                    \
 196         [ELF_T_NHDR]    = elf_cvt_note,                                       \
 197         [ELF_T_SYMINFO] = ElfW2(Bits, cvt_Syminfo),                           \
 198         [ELF_T_MOVE]    = ElfW2(Bits, cvt_Move),                              \
 199         [ELF_T_LIB]     = ElfW2(Bits, cvt_Lib),                               \
 200         [ELF_T_AUXV]    = ElfW2(Bits, cvt_auxv_t)
 201         define_xfcts (32),
 202         [ELF_T_GNUHASH] = Elf32_cvt_Word
 203       },
 204       [ELFCLASS64 - 1] = {
 205         define_xfcts (64),
 206         [ELF_T_GNUHASH] = elf_cvt_gnuhash
 207       }
 208     }
 209   }
 210 };
 211 /* For now we only handle the case where the memory representation is the
 212    same as the file representation.  Should this change we have to define
 213    separate functions.  For now reuse them.  */
 214 strong_alias (__elf_xfctstom, __elf_xfctstof)