elf/dynamic-link.h

   1 /* Inline functions for dynamic linking.
   2    Copyright (C) 1995,96,97,98,99,2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <elf.h>
  21 #include <dl-machine.h>
  22 #include <assert.h>
  23
  24 #ifndef VERSYMIDX
  25 # define VERSYMIDX(sym) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (sym))
  26 #endif
  27
  28
  29 /* Global read-only variable defined in rtld.c which is nonzero if we
  30    shall give more warning messages.  */
  31 extern int _dl_verbose __attribute__ ((unused));
  32
  33
  34 /* Read the dynamic section at DYN and fill in INFO with indices DT_*.  */
  35
  36 static inline void __attribute__ ((unused))
  37 elf_get_dynamic_info (struct link_map *l)
  38 {
  39   ElfW(Dyn) *dyn = l->l_ld;
  40   ElfW(Addr) l_addr;
  41   ElfW(Dyn) **info;
  42
  43   if (! dyn)
  44     return;
  45
  46   l_addr = l->l_addr;
  47   info = l->l_info;
  48
  49   while (dyn->d_tag != DT_NULL)
  50     {
  51       if (dyn->d_tag < DT_NUM)
  52         info[dyn->d_tag] = dyn;
  53       else if (dyn->d_tag >= DT_LOPROC &&
  54                dyn->d_tag < DT_LOPROC + DT_THISPROCNUM)
  55         info[dyn->d_tag - DT_LOPROC + DT_NUM] = dyn;
  56       else if ((Elf32_Word) DT_VERSIONTAGIDX (dyn->d_tag) < DT_VERSIONTAGNUM)
  57         info[VERSYMIDX (dyn->d_tag)] = dyn;
  58       else if ((Elf32_Word) DT_EXTRATAGIDX (dyn->d_tag) < DT_EXTRANUM)
  59         info[DT_EXTRATAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
  60              + DT_VERSIONTAGNUM] = dyn;
  61       else
  62         assert (! "bad dynamic tag");
  63       ++dyn;
  64     }
  65 #ifndef DL_RO_DYN_SECTION
  66   if (info[DT_PLTGOT] != NULL)
  67     info[DT_PLTGOT]->d_un.d_ptr += l_addr;
  68   if (info[DT_STRTAB] != NULL)
  69     info[DT_STRTAB]->d_un.d_ptr += l_addr;
  70   if (info[DT_SYMTAB] != NULL)
  71     info[DT_SYMTAB]->d_un.d_ptr += l_addr;
  72 # if ! ELF_MACHINE_NO_RELA
  73   if (info[DT_RELA] != NULL)
  74     {
  75       assert (info[DT_RELAENT]->d_un.d_val == sizeof (ElfW(Rela)));
  76       info[DT_RELA]->d_un.d_ptr += l_addr;
  77     }
  78 # endif
  79 # if ! ELF_MACHINE_NO_REL
  80   if (info[DT_REL] != NULL)
  81     {
  82       assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
  83       info[DT_REL]->d_un.d_ptr += l_addr;
  84     }
  85 # endif
  86 #endif
  87   if (info[DT_PLTREL] != NULL)
  88     {
  89 # if ELF_MACHINE_NO_RELA
  90       assert (info[DT_PLTREL]->d_un.d_val == DT_REL);
  91 # elif ELF_MACHINE_NO_REL
  92       assert (info[DT_PLTREL]->d_un.d_val == DT_RELA);
  93 # else
  94       assert (info[DT_PLTREL]->d_un.d_val == DT_REL
  95               || info[DT_PLTREL]->d_un.d_val == DT_RELA);
  96 # endif
  97     }
  98 #ifndef DL_RO_DYN_SECTION
  99   if (info[DT_JMPREL] != NULL)
 100     info[DT_JMPREL]->d_un.d_ptr += l_addr;
 101   if (info[VERSYMIDX (DT_VERSYM)] != NULL)
 102     info[VERSYMIDX (DT_VERSYM)]->d_un.d_ptr += l_addr;
 103 #endif
 104   if (info[DT_FLAGS] != NULL)
 105     {
 106       /* Flags are used.  Translate to the old form where available.
 107          Since these l_info entries are only tested for NULL pointers it
 108          is ok if they point to the DT_FLAGS entry.  */
 109       ElfW(Word) flags = info[DT_FLAGS]->d_un.d_val;
 110       if (flags & DF_SYMBOLIC)
 111         info[DT_SYMBOLIC] = info[DT_FLAGS];
 112       if (flags & DF_TEXTREL)
 113         info[DT_TEXTREL] = info[DT_FLAGS];
 114       if (flags & DF_BIND_NOW)
 115         info[DT_BIND_NOW] = info[DT_FLAGS];
 116     }
 117   if (info[DT_RUNPATH] != NULL)
 118     /* If both RUNPATH and RPATH are given, the latter is ignored.  */
 119     info[DT_RPATH] = NULL;
 120 }
 121
 122 #ifdef RESOLVE
 123
 124 /* Get the definitions of `elf_dynamic_do_rel' and `elf_dynamic_do_rela'.
 125    These functions are almost identical, so we use cpp magic to avoid
 126    duplicating their code.  It cannot be done in a more general function
 127    because we must be able to completely inline.  */
 128
 129 /* On some machines, notably SPARC, DT_REL* includes DT_JMPREL in its
 130    range.  Note that according to the ELF spec, this is completely legal!
 131    But conditionally define things so that on machines we know this will
 132    not happen we do something more optimal.  */
 133
 134 # ifdef ELF_MACHINE_PLTREL_OVERLAP
 135 #  define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, do_lazy, test_rel) \
 136   do {                                                                        \
 137     struct { ElfW(Addr) start, size; int lazy; } ranges[3];                   \
 138     int ranges_index;                                                         \
 139                                                                               \
 140     ranges[0].lazy = ranges[2].lazy = 0;                                      \
 141     ranges[1].lazy = 1;                                                       \
 142     ranges[0].size = ranges[1].size = ranges[2].size = 0;                     \
 143                                                                               \
 144     if ((map)->l_info[DT_##RELOC])                                            \
 145       {                                                                       \
 146         ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]);                  \
 147         ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val;           \
 148       }                                                                       \
 149                                                                               \
 150      if ((do_lazy)                                                            \
 151         && (map)->l_info[DT_PLTREL]                                           \
 152         && (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
 153       {                                                                       \
 154         ranges[1].start = D_PTR ((map), l_info[DT_JMPREL]);                   \
 155         ranges[1].size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val;              \
 156         ranges[2].start = ranges[1].start + ranges[1].size;                   \
 157         ranges[2].size = ranges[0].start + ranges[0].size - ranges[2].start;  \
 158         ranges[0].size = ranges[1].start - ranges[0].start;                   \
 159       }                                                                       \
 160                                                                               \
 161     for (ranges_index = 0; ranges_index < 3; ++ranges_index)                  \
 162       elf_dynamic_do_##reloc ((map),                                          \
 163                               ranges[ranges_index].start,                     \
 164                               ranges[ranges_index].size,                      \
 165                               ranges[ranges_index].lazy);                     \
 166   } while (0)
 167 # else
 168 #  define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, do_lazy, test_rel) \
 169   do {                                                                        \
 170     struct { ElfW(Addr) start, size; int lazy; } ranges[2];                   \
 171     int ranges_index;                                                         \
 172     ranges[0].lazy = 0;                                                       \
 173     ranges[0].size = ranges[1].size = 0;                                      \
 174     ranges[0].start = 0;                                                      \
 175                                                                               \
 176     if ((map)->l_info[DT_##RELOC])                                            \
 177       {                                                                       \
 178         ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]);                  \
 179         ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val;           \
 180       }                                                                       \
 181     if ((map)->l_info[DT_PLTREL]                                              \
 182         && (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
 183       {                                                                       \
 184         ElfW(Addr) start = D_PTR ((map), l_info[DT_JMPREL]);                  \
 185                                                                               \
 186         if ((do_lazy)                                                         \
 187             /* This test does not only detect whether the relocation          \
 188                sections are in the right order, it also checks whether        \
 189                there is a DT_REL/DT_RELA section.  */                         \
 190             || ranges[0].start + ranges[0].size != start)                     \
 191           {                                                                   \
 192             ranges[1].start = start;                                          \
 193             ranges[1].size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val;          \
 194             ranges[1].lazy = (do_lazy);                                       \
 195           }                                                                   \
 196         else                                                                  \
 197           /* Combine processing the sections.  */                             \
 198           ranges[0].size += (map)->l_info[DT_PLTRELSZ]->d_un.d_val;           \
 199       }                                                                       \
 200                                                                               \
 201     for (ranges_index = 0; ranges_index < 2; ++ranges_index)                  \
 202       elf_dynamic_do_##reloc ((map),                                          \
 203                               ranges[ranges_index].start,                     \
 204                               ranges[ranges_index].size,                      \
 205                               ranges[ranges_index].lazy);                     \
 206   } while (0)
 207 # endif
 208
 209 # if ELF_MACHINE_NO_REL || ELF_MACHINE_NO_RELA
 210 #  define _ELF_CHECK_REL 0
 211 # else
 212 #  define _ELF_CHECK_REL 1
 213 # endif
 214
 215 # if ! ELF_MACHINE_NO_REL
 216 #  include "do-rel.h"
 217 #  define ELF_DYNAMIC_DO_REL(map, lazy) \
 218   _ELF_DYNAMIC_DO_RELOC (REL, rel, map, lazy, _ELF_CHECK_REL)
 219 # else
 220 #  define ELF_DYNAMIC_DO_REL(map, lazy) /* Nothing to do.  */
 221 # endif
 222
 223 # if ! ELF_MACHINE_NO_RELA
 224 #  define DO_RELA
 225 #  include "do-rel.h"
 226 #  define ELF_DYNAMIC_DO_RELA(map, lazy) \
 227   _ELF_DYNAMIC_DO_RELOC (RELA, rela, map, lazy, _ELF_CHECK_REL)
 228 # else
 229 #  define ELF_DYNAMIC_DO_RELA(map, lazy) /* Nothing to do.  */
 230 # endif
 231
 232 /* This can't just be an inline function because GCC is too dumb
 233    to inline functions containing inlines themselves.  */
 234 # define ELF_DYNAMIC_RELOCATE(map, lazy, consider_profile) \
 235   do {                                                                        \
 236     int edr_lazy = elf_machine_runtime_setup ((map), (lazy),                  \
 237                                               (consider_profile));            \
 238     ELF_DYNAMIC_DO_REL ((map), edr_lazy);                                     \
 239     ELF_DYNAMIC_DO_RELA ((map), edr_lazy);                                    \
 240   } while (0)
 241
 242 #endif