elf/dynamic-link.h

   1 /* Inline functions for dynamic linking.
   2    Copyright (C) 1995,96,97,98,99,2000,2001,2002 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    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 /* Read the dynamic section at DYN and fill in INFO with indices DT_*.  */
  30
  31 static inline void __attribute__ ((unused))
  32 elf_get_dynamic_info (struct link_map *l)
  33 {
  34   ElfW(Dyn) *dyn = l->l_ld;
  35   ElfW(Dyn) **info;
  36
  37 #ifndef RTLD_BOOTSTRAP
  38   if (dyn == NULL)
  39     return;
  40 #endif
  41
  42   info = l->l_info;
  43
  44   while (dyn->d_tag != DT_NULL)
  45     {
  46       if (dyn->d_tag < DT_NUM)
  47         info[dyn->d_tag] = dyn;
  48       else if (dyn->d_tag >= DT_LOPROC &&
  49                dyn->d_tag < DT_LOPROC + DT_THISPROCNUM)
  50         info[dyn->d_tag - DT_LOPROC + DT_NUM] = dyn;
  51       else if ((Elf32_Word) DT_VERSIONTAGIDX (dyn->d_tag) < DT_VERSIONTAGNUM)
  52         info[VERSYMIDX (dyn->d_tag)] = dyn;
  53       else if ((Elf32_Word) DT_EXTRATAGIDX (dyn->d_tag) < DT_EXTRANUM)
  54         info[DT_EXTRATAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
  55              + DT_VERSIONTAGNUM] = dyn;
  56       else if ((Elf32_Word) DT_VALTAGIDX (dyn->d_tag) < DT_VALNUM)
  57         info[DT_VALTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
  58              + DT_VERSIONTAGNUM + DT_EXTRANUM] = dyn;
  59       else if ((Elf32_Word) DT_ADDRTAGIDX (dyn->d_tag) < DT_ADDRNUM)
  60         info[DT_ADDRTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
  61              + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM] = dyn;
  62       ++dyn;
  63     }
  64 #ifndef DL_RO_DYN_SECTION
  65   /* Don't adjust .dynamic unnecessarily.  */
  66   if (l->l_addr != 0)
  67     {
  68       ElfW(Addr) l_addr = l->l_addr;
  69
  70       if (info[DT_PLTGOT] != NULL)
  71         info[DT_PLTGOT]->d_un.d_ptr += l_addr;
  72       if (info[DT_STRTAB] != NULL)
  73         info[DT_STRTAB]->d_un.d_ptr += l_addr;
  74       if (info[DT_SYMTAB] != NULL)
  75         info[DT_SYMTAB]->d_un.d_ptr += l_addr;
  76 # if ! ELF_MACHINE_NO_RELA
  77       if (info[DT_RELA] != NULL)
  78         info[DT_RELA]->d_un.d_ptr += l_addr;
  79 # endif
  80 # if ! ELF_MACHINE_NO_REL
  81       if (info[DT_REL] != NULL)
  82         info[DT_REL]->d_un.d_ptr += l_addr;
  83 # endif
  84       if (info[DT_JMPREL] != NULL)
  85         info[DT_JMPREL]->d_un.d_ptr += l_addr;
  86       if (info[VERSYMIDX (DT_VERSYM)] != NULL)
  87         info[VERSYMIDX (DT_VERSYM)]->d_un.d_ptr += l_addr;
  88     }
  89 #endif
  90   if (info[DT_PLTREL] != NULL)
  91     {
  92 #if ELF_MACHINE_NO_RELA
  93       assert (info[DT_PLTREL]->d_un.d_val == DT_REL);
  94 #elif ELF_MACHINE_NO_REL
  95       assert (info[DT_PLTREL]->d_un.d_val == DT_RELA);
  96 #else
  97       assert (info[DT_PLTREL]->d_un.d_val == DT_REL
  98               || info[DT_PLTREL]->d_un.d_val == DT_RELA);
  99 #endif
 100     }
 101 #if ! ELF_MACHINE_NO_RELA
 102   if (info[DT_RELA] != NULL)
 103     assert (info[DT_RELAENT]->d_un.d_val == sizeof (ElfW(Rela)));
 104 # endif
 105 # if ! ELF_MACHINE_NO_REL
 106   if (info[DT_REL] != NULL)
 107     assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
 108 #endif
 109   if (info[DT_FLAGS] != NULL)
 110     {
 111       /* Flags are used.  Translate to the old form where available.
 112          Since these l_info entries are only tested for NULL pointers it
 113          is ok if they point to the DT_FLAGS entry.  */
 114       l->l_flags = info[DT_FLAGS]->d_un.d_val;
 115 #ifdef RTLD_BOOTSTRAP
 116       /* These three flags must not be set for ld.so.  */
 117       assert ((l->l_flags & (DF_SYMBOLIC | DF_TEXTREL | DF_BIND_NOW)) == 0);
 118 #else
 119       if (l->l_flags & DF_SYMBOLIC)
 120         info[DT_SYMBOLIC] = info[DT_FLAGS];
 121       if (l->l_flags & DF_TEXTREL)
 122         info[DT_TEXTREL] = info[DT_FLAGS];
 123       if (l->l_flags & DF_BIND_NOW)
 124         info[DT_BIND_NOW] = info[DT_FLAGS];
 125 #endif
 126     }
 127   if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
 128     l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
 129 #ifdef RTLD_BOOTSTRAP
 130   /* The dynamic linker should have none of these set.  */
 131   assert (info[DT_RUNPATH] == NULL);
 132   assert (info[DT_RPATH] == NULL);
 133 #else
 134   if (info[DT_RUNPATH] != NULL)
 135     /* If both RUNPATH and RPATH are given, the latter is ignored.  */
 136     info[DT_RPATH] = NULL;
 137 #endif
 138 }
 139
 140 #ifdef RESOLVE
 141
 142 # ifdef RTLD_BOOTSTRAP
 143 #  define ELF_DURING_STARTUP (1)
 144 # else
 145 #  define ELF_DURING_STARTUP (0)
 146 # endif
 147
 148 /* Get the definitions of `elf_dynamic_do_rel' and `elf_dynamic_do_rela'.
 149    These functions are almost identical, so we use cpp magic to avoid
 150    duplicating their code.  It cannot be done in a more general function
 151    because we must be able to completely inline.  */
 152
 153 /* On some machines, notably SPARC, DT_REL* includes DT_JMPREL in its
 154    range.  Note that according to the ELF spec, this is completely legal!
 155    But conditionally define things so that on machines we know this will
 156    not happen we do something more optimal.  */
 157
 158 # ifdef ELF_MACHINE_PLTREL_OVERLAP
 159 #  define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, do_lazy, test_rel) \
 160   do {                                                                        \
 161     struct { ElfW(Addr) start, size; int lazy; } ranges[3];                   \
 162     int ranges_index;                                                         \
 163                                                                               \
 164     ranges[0].lazy = ranges[2].lazy = 0;                                      \
 165     ranges[1].lazy = 1;                                                       \
 166     ranges[0].size = ranges[1].size = ranges[2].size = 0;                     \
 167                                                                               \
 168     if ((map)->l_info[DT_##RELOC])                                            \
 169       {                                                                       \
 170         ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]);                  \
 171         ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val;           \
 172       }                                                                       \
 173                                                                               \
 174     if ((do_lazy)                                                             \
 175         && (map)->l_info[DT_PLTREL]                                           \
 176         && (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
 177       {                                                                       \
 178         ranges[1].start = D_PTR ((map), l_info[DT_JMPREL]);                   \
 179         ranges[1].size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val;              \
 180         ranges[2].start = ranges[1].start + ranges[1].size;                   \
 181         ranges[2].size = ranges[0].start + ranges[0].size - ranges[2].start;  \
 182         ranges[0].size = ranges[1].start - ranges[0].start;                   \
 183       }                                                                       \
 184                                                                               \
 185     for (ranges_index = 0; ranges_index < 3; ++ranges_index)                  \
 186       elf_dynamic_do_##reloc ((map),                                          \
 187                               ranges[ranges_index].start,                     \
 188                               ranges[ranges_index].size,                      \
 189                               ranges[ranges_index].lazy);                     \
 190   } while (0)
 191 # else
 192 #  define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, do_lazy, test_rel) \
 193   do {                                                                        \
 194     struct { ElfW(Addr) start, size; int lazy; } ranges[2];                   \
 195     ranges[0].lazy = 0;                                                       \
 196     ranges[0].size = ranges[1].size = 0;                                      \
 197     ranges[0].start = 0;                                                      \
 198                                                                               \
 199     if ((map)->l_info[DT_##RELOC])                                            \
 200       {                                                                       \
 201         ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]);                  \
 202         ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val;           \
 203       }                                                                       \
 204     if ((map)->l_info[DT_PLTREL]                                              \
 205         && (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
 206       {                                                                       \
 207         ElfW(Addr) start = D_PTR ((map), l_info[DT_JMPREL]);                  \
 208                                                                               \
 209         if (! ELF_DURING_STARTUP                                              \
 210             && ((do_lazy)                                                     \
 211                 /* This test does not only detect whether the relocation      \
 212                    sections are in the right order, it also checks whether    \
 213                    there is a DT_REL/DT_RELA section.  */                     \
 214                 || ranges[0].start + ranges[0].size != start))                \
 215           {                                                                   \
 216             ranges[1].start = start;                                          \
 217             ranges[1].size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val;          \
 218             ranges[1].lazy = (do_lazy);                                       \
 219           }                                                                   \
 220         else                                                                  \
 221           {                                                                   \
 222             /* Combine processing the sections.  */                           \
 223             assert (ranges[0].start + ranges[0].size == start);               \
 224             ranges[0].size += (map)->l_info[DT_PLTRELSZ]->d_un.d_val;         \
 225           }                                                                   \
 226       }                                                                       \
 227                                                                               \
 228     if (ELF_DURING_STARTUP)                                                   \
 229       elf_dynamic_do_##reloc ((map), ranges[0].start, ranges[0].size, 0);     \
 230     else                                                                      \
 231       {                                                                       \
 232         int ranges_index;                                                     \
 233         for (ranges_index = 0; ranges_index < 2; ++ranges_index)              \
 234           elf_dynamic_do_##reloc ((map),                                      \
 235                                   ranges[ranges_index].start,                 \
 236                                   ranges[ranges_index].size,                  \
 237                                   ranges[ranges_index].lazy);                 \
 238       }                                                                       \
 239   } while (0)
 240 # endif
 241
 242 # if ELF_MACHINE_NO_REL || ELF_MACHINE_NO_RELA
 243 #  define _ELF_CHECK_REL 0
 244 # else
 245 #  define _ELF_CHECK_REL 1
 246 # endif
 247
 248 # if ! ELF_MACHINE_NO_REL
 249 #  include "do-rel.h"
 250 #  define ELF_DYNAMIC_DO_REL(map, lazy) \
 251   _ELF_DYNAMIC_DO_RELOC (REL, rel, map, lazy, _ELF_CHECK_REL)
 252 # else
 253 #  define ELF_DYNAMIC_DO_REL(map, lazy) /* Nothing to do.  */
 254 # endif
 255
 256 # if ! ELF_MACHINE_NO_RELA
 257 #  define DO_RELA
 258 #  include "do-rel.h"
 259 #  define ELF_DYNAMIC_DO_RELA(map, lazy) \
 260   _ELF_DYNAMIC_DO_RELOC (RELA, rela, map, lazy, _ELF_CHECK_REL)
 261 # else
 262 #  define ELF_DYNAMIC_DO_RELA(map, lazy) /* Nothing to do.  */
 263 # endif
 264
 265 /* This can't just be an inline function because GCC is too dumb
 266    to inline functions containing inlines themselves.  */
 267 # define ELF_DYNAMIC_RELOCATE(map, lazy, consider_profile) \
 268   do {                                                                        \
 269     int edr_lazy = elf_machine_runtime_setup ((map), (lazy),                  \
 270                                               (consider_profile));            \
 271     ELF_DYNAMIC_DO_REL ((map), edr_lazy);                                     \
 272     ELF_DYNAMIC_DO_RELA ((map), edr_lazy);                                    \
 273   } while (0)
 274
 275 #endif