elf/get-dynamic-info.h

   1 /* Read the dynamic section at DYN and fill in INFO with indices DT_*.
   2    Copyright (C) 2012-2013 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20
  21 #ifndef RESOLVE_MAP
  22 static
  23 #else
  24 auto
  25 #endif
  26 inline void __attribute__ ((unused, always_inline))
  27 elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
  28 {
  29   ElfW(Dyn) *dyn = l->l_ld;
  30   ElfW(Dyn) **info;
  31 #if __ELF_NATIVE_CLASS == 32
  32   typedef Elf32_Word d_tag_utype;
  33 #elif __ELF_NATIVE_CLASS == 64
  34   typedef Elf64_Xword d_tag_utype;
  35 #endif
  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 ((d_tag_utype) 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 ((d_tag_utype) DT_VERSIONTAGIDX (dyn->d_tag) < DT_VERSIONTAGNUM)
  52         info[VERSYMIDX (dyn->d_tag)] = dyn;
  53       else if ((d_tag_utype) 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 ((d_tag_utype) 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 ((d_tag_utype) 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
  65 #define DL_RO_DYN_TEMP_CNT      8
  66
  67 #ifndef DL_RO_DYN_SECTION
  68   /* Don't adjust .dynamic unnecessarily.  */
  69   if (l->l_addr != 0)
  70     {
  71       ElfW(Addr) l_addr = l->l_addr;
  72       int cnt = 0;
  73
  74 # define ADJUST_DYN_INFO(tag) \
  75       do                                                                      \
  76         if (info[tag] != NULL)                                                \
  77           {                                                                   \
  78             if (temp)                                                         \
  79               {                                                               \
  80                 temp[cnt].d_tag = info[tag]->d_tag;                           \
  81                 temp[cnt].d_un.d_ptr = info[tag]->d_un.d_ptr + l_addr;        \
  82                 info[tag] = temp + cnt++;                                     \
  83               }                                                               \
  84             else                                                              \
  85               info[tag]->d_un.d_ptr += l_addr;                                \
  86           }                                                                   \
  87       while (0)
  88
  89       ADJUST_DYN_INFO (DT_HASH);
  90       ADJUST_DYN_INFO (DT_PLTGOT);
  91       ADJUST_DYN_INFO (DT_STRTAB);
  92       ADJUST_DYN_INFO (DT_SYMTAB);
  93 # if ! ELF_MACHINE_NO_RELA
  94       ADJUST_DYN_INFO (DT_RELA);
  95 # endif
  96 # if ! ELF_MACHINE_NO_REL
  97       ADJUST_DYN_INFO (DT_REL);
  98 # endif
  99       ADJUST_DYN_INFO (DT_JMPREL);
 100       ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
 101       ADJUST_DYN_INFO (DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + DT_THISPROCNUM
 102                        + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM);
 103 # undef ADJUST_DYN_INFO
 104       assert (cnt <= DL_RO_DYN_TEMP_CNT);
 105     }
 106 #endif
 107   if (info[DT_PLTREL] != NULL)
 108     {
 109 #if ELF_MACHINE_NO_RELA
 110       assert (info[DT_PLTREL]->d_un.d_val == DT_REL);
 111 #elif ELF_MACHINE_NO_REL
 112       assert (info[DT_PLTREL]->d_un.d_val == DT_RELA);
 113 #else
 114       assert (info[DT_PLTREL]->d_un.d_val == DT_REL
 115               || info[DT_PLTREL]->d_un.d_val == DT_RELA);
 116 #endif
 117     }
 118 #if ! ELF_MACHINE_NO_RELA
 119   if (info[DT_RELA] != NULL)
 120     assert (info[DT_RELAENT]->d_un.d_val == sizeof (ElfW(Rela)));
 121 # endif
 122 # if ! ELF_MACHINE_NO_REL
 123   if (info[DT_REL] != NULL)
 124     assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
 125 #endif
 126 #ifdef RTLD_BOOTSTRAP
 127   /* Only the bind now flags are allowed.  */
 128   assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
 129           || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
 130   assert (info[DT_FLAGS] == NULL
 131           || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
 132   /* Flags must not be set for ld.so.  */
 133   assert (info[DT_RUNPATH] == NULL);
 134   assert (info[DT_RPATH] == NULL);
 135 #else
 136   if (info[DT_FLAGS] != NULL)
 137     {
 138       /* Flags are used.  Translate to the old form where available.
 139          Since these l_info entries are only tested for NULL pointers it
 140          is ok if they point to the DT_FLAGS entry.  */
 141       l->l_flags = info[DT_FLAGS]->d_un.d_val;
 142
 143       if (l->l_flags & DF_SYMBOLIC)
 144         info[DT_SYMBOLIC] = info[DT_FLAGS];
 145       if (l->l_flags & DF_TEXTREL)
 146         info[DT_TEXTREL] = info[DT_FLAGS];
 147       if (l->l_flags & DF_BIND_NOW)
 148         info[DT_BIND_NOW] = info[DT_FLAGS];
 149     }
 150   if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
 151     {
 152       l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
 153
 154       /* Only DT_1_SUPPORTED_MASK bits are supported, and we would like
 155          to assert this, but we can't. Users have been setting
 156          unsupported DF_1_* flags for a long time and glibc has ignored
 157          them. Therefore to avoid breaking existing applications the
 158          best we can do is add a warning during debugging with the
 159          intent of notifying the user of the problem.  */
 160       if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0)
 161           && l->l_flags_1 & ~DT_1_SUPPORTED_MASK)
 162         _dl_debug_printf ("\nWARNING: Unsupported flag value(s) of 0x%x in DT_FLAGS_1.\n",
 163                           l->l_flags_1 & ~DT_1_SUPPORTED_MASK);
 164
 165       if (l->l_flags_1 & DF_1_NOW)
 166         info[DT_BIND_NOW] = info[VERSYMIDX (DT_FLAGS_1)];
 167     }
 168   if (info[DT_RUNPATH] != NULL)
 169     /* If both RUNPATH and RPATH are given, the latter is ignored.  */
 170     info[DT_RPATH] = NULL;
 171 #endif
 172 }