libelf/gelf_xlate.c

   1 /* Transformation functions for ELF data types.
   2    Copyright (C) 1998,1999,2000,2002,2004,2005,2006,2007,2015 Red Hat, Inc.
   3    Copyright (C) 2022 Mark J. Wielaard <mark@klomp.org>
   4    This file is part of elfutils.
   5    Written by Ulrich Drepper <drepper@redhat.com>, 1998.
   6
   7    This file is free software; you can redistribute it and/or modify
   8    it under the terms of either
   9
  10      * the GNU Lesser General Public License as published by the Free
  11        Software Foundation; either version 3 of the License, or (at
  12        your option) any later version
  13
  14    or
  15
  16      * the GNU General Public License as published by the Free
  17        Software Foundation; either version 2 of the License, or (at
  18        your option) any later version
  19
  20    or both in parallel, as here.
  21
  22    elfutils is distributed in the hope that it will be useful, but
  23    WITHOUT ANY WARRANTY; without even the implied warranty of
  24    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25    General Public License for more details.
  26
  27    You should have received copies of the GNU General Public License and
  28    the GNU Lesser General Public License along with this program.  If
  29    not, see <http://www.gnu.org/licenses/>.  */
  30
  31 #ifdef HAVE_CONFIG_H
  32 # include <config.h>
  33 #endif
  34
  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   if (n != 0)
  56     memmove (dest, src, n);
  57 }
  58
  59
  60 /* We'll optimize the definition of the conversion functions here a
  61    bit.  We need only functions for 16, 32, and 64 bits.  The
  62    functions referenced in the table will be aliases for one of these
  63    functions.  Which one is decided by the ELFxx_FSZ_type.  */
  64
  65 #if ALLOW_UNALIGNED
  66
  67 #define FETCH(Bits, ptr)        (*(const uint##Bits##_t *) ptr)
  68 #define STORE(Bits, ptr, val)   (*(uint##Bits##_t *) ptr = val)
  69
  70 #else
  71
  72 union unaligned
  73   {
  74     uint16_t u16;
  75     uint32_t u32;
  76     uint64_t u64;
  77   } attribute_packed;
  78
  79 #define FETCH(Bits, ptr)        (((const union unaligned *) ptr)->u##Bits)
  80 #define STORE(Bits, ptr, val)   (((union unaligned *) ptr)->u##Bits = val)
  81
  82 #endif
  83
  84 /* Now define the conversion functions for the basic types.  We use here
  85    the fact that file and memory types are the same and that we have the
  86    ELFxx_FSZ_* macros.
  87
  88    At the same time we define inline functions which we will use to
  89    convert the complex types.  */
  90 #define FUNDAMENTAL(NAME, Name, Bits) \
  91   INLINE2 (ELFW2(Bits,FSZ_##NAME), ElfW2(Bits,cvt_##Name), ElfW2(Bits,Name))
  92 #define INLINE2(Bytes, FName, TName) \
  93   INLINE3 (Bytes, FName, TName)
  94 #define INLINE3(Bytes, FName, TName)                                          \
  95   static inline void FName##1 (void *dest, const void *ptr)                   \
  96   {                                                                           \
  97     switch (Bytes)                                                            \
  98       {                                                                       \
  99       case 2: STORE (16, dest, bswap_16 (FETCH (16, ptr))); break;            \
 100       case 4: STORE (32, dest, bswap_32 (FETCH (32, ptr))); break;            \
 101       case 8: STORE (64, dest, bswap_64 (FETCH (64, ptr))); break;            \
 102       default:                                                                \
 103         abort ();                                                             \
 104       }                                                                       \
 105   }                                                                           \
 106                                                                               \
 107   static void FName (void *dest, const void *ptr, size_t len,                 \
 108                      int encode __attribute__ ((unused)))                     \
 109   {                                                                           \
 110     size_t n = len / sizeof (TName);                                          \
 111     if (dest < ptr)                                                           \
 112       while (n-- > 0)                                                         \
 113         {                                                                     \
 114           FName##1 (dest, ptr);                                               \
 115           dest += Bytes;                                                      \
 116           ptr += Bytes;                                                       \
 117         }                                                                     \
 118     else                                                                      \
 119       {                                                                       \
 120         dest += len;                                                          \
 121         ptr += len;                                                           \
 122         while (n-- > 0)                                                       \
 123           {                                                                   \
 124             ptr -= Bytes;                                                     \
 125             dest -= Bytes;                                                    \
 126             FName##1 (dest, ptr);                                             \
 127           }                                                                   \
 128       }                                                                       \
 129   }
 130
 131
 132 /* Now the tricky part: define the transformation functions for the
 133    complex types.  We will use the definitions of the types in
 134    abstract.h.  */
 135 #define START(Bits, Name, EName) \
 136   static void                                                                 \
 137   ElfW2 (Bits, cvt_##Name) (void *dest, const void *src, size_t len,          \
 138                             int encode __attribute__ ((unused)))              \
 139   { ElfW2(Bits, Name) *tdest = (ElfW2(Bits, Name) *) dest;                    \
 140     ElfW2(Bits, Name) *tsrc = (ElfW2(Bits, Name) *) src;                      \
 141     size_t sz = sizeof (ElfW2(Bits, Name));                                   \
 142     size_t n;                                                                 \
 143     for (n = len / sz; n > 0; ++tdest, ++tsrc, --n) {
 144 #define END(Bits, Name)                                                       \
 145     }                                                                         \
 146     if (len % sz > 0) /* Cannot convert partial structures, just copy. */     \
 147       memmove (dest, src, len % sz);                                          \
 148   }
 149 #define TYPE_EXTRA(Code)
 150 #define TYPE_XLATE(Code) Code
 151 #define TYPE_NAME(Type, Name) TYPE_NAME2 (Type, Name)
 152 #define TYPE_NAME2(Type, Name) Type##1 (&tdest->Name, &tsrc->Name);
 153 #define TYPE(Name, Bits) TYPE2 (Name, Bits)
 154 #define TYPE2(Name, Bits) TYPE3 (Name##Bits)
 155 #define TYPE3(Name) Name (cvt_)
 156
 157 /* Signal that we are generating conversion functions.  */
 158 #define GENERATE_CONVERSION
 159
 160 /* First generate the 32-bit conversion functions.  */
 161 #define LIBELFBITS 32
 162 #include "gelf_xlate.h"
 163
 164 /* Now generate the 64-bit conversion functions.  */
 165 #define LIBELFBITS 64
 166 #include "gelf_xlate.h"
 167
 168
 169 /* We have a few functions which we must create by hand since the sections
 170    do not contain records of only one type.  */
 171 #include "version_xlate.h"
 172 #include "gnuhash_xlate.h"
 173 #include "note_xlate.h"
 174 #include "chdr_xlate.h"
 175
 176
 177 /* Now the externally visible table with the function pointers.  */
 178 const xfct_t __elf_xfctstom[ELFCLASSNUM - 1][ELF_T_NUM] =
 179 {
 180       [ELFCLASS32 - 1] = {
 181 #define define_xfcts(Bits) \
 182         [ELF_T_BYTE]    = elf_cvt_Byte,                                       \
 183         [ELF_T_ADDR]    = ElfW2(Bits, cvt_Addr),                              \
 184         [ELF_T_DYN]     = ElfW2(Bits, cvt_Dyn),                               \
 185         [ELF_T_EHDR]    = ElfW2(Bits, cvt_Ehdr),                              \
 186         [ELF_T_HALF]    = ElfW2(Bits, cvt_Half),                              \
 187         [ELF_T_OFF]     = ElfW2(Bits, cvt_Off),                               \
 188         [ELF_T_PHDR]    = ElfW2(Bits, cvt_Phdr),                              \
 189         [ELF_T_RELA]    = ElfW2(Bits, cvt_Rela),                              \
 190         [ELF_T_REL]     = ElfW2(Bits, cvt_Rel),                               \
 191         [ELF_T_SHDR]    = ElfW2(Bits, cvt_Shdr),                              \
 192         [ELF_T_SWORD]   = ElfW2(Bits, cvt_Sword),                             \
 193         [ELF_T_SYM]     = ElfW2(Bits, cvt_Sym),                               \
 194         [ELF_T_WORD]    = ElfW2(Bits, cvt_Word),                              \
 195         [ELF_T_XWORD]   = ElfW2(Bits, cvt_Xword),                             \
 196         [ELF_T_SXWORD]  = ElfW2(Bits, cvt_Sxword),                            \
 197         [ELF_T_VDEF]    = elf_cvt_Verdef,                                     \
 198         [ELF_T_VDAUX]   = elf_cvt_Verdef,                                     \
 199         [ELF_T_VNEED]   = elf_cvt_Verneed,                                    \
 200         [ELF_T_VNAUX]   = elf_cvt_Verneed,                                    \
 201         [ELF_T_NHDR]    = elf_cvt_note4,                                      \
 202         [ELF_T_NHDR8]   = elf_cvt_note8,                                      \
 203         [ELF_T_SYMINFO] = ElfW2(Bits, cvt_Syminfo),                           \
 204         [ELF_T_MOVE]    = ElfW2(Bits, cvt_Move),                              \
 205         [ELF_T_LIB]     = ElfW2(Bits, cvt_Lib),                               \
 206         [ELF_T_AUXV]    = ElfW2(Bits, cvt_auxv_t),                            \
 207         [ELF_T_CHDR]    = ElfW2(Bits, cvt_chdr),                              \
 208         [ELF_T_RELR]    = ElfW2(Bits, cvt_Relr)
 209         define_xfcts (32),
 210         [ELF_T_GNUHASH] = Elf32_cvt_Word
 211       },
 212       [ELFCLASS64 - 1] = {
 213         define_xfcts (64),
 214         [ELF_T_GNUHASH] = elf_cvt_gnuhash
 215       }
 216 };