elf/get-dynamic-info.h

   1 /* Read the dynamic section at DYN and fill in INFO with indices DT_*.
   2    Copyright (C) 2012-2017 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 #include <libc-internal.h>
  21
  22 #ifndef RESOLVE_MAP
  23 static
  24 #else
  25 auto
  26 #endif
  27 inline void __attribute__ ((unused, always_inline))
  28 elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
  29 {
  30   ElfW(Dyn) *dyn = l->l_ld;
  31   ElfW(Dyn) **info;
  32 #if __ELF_NATIVE_CLASS == 32
  33   typedef Elf32_Word d_tag_utype;
  34 #elif __ELF_NATIVE_CLASS == 64
  35   typedef Elf64_Xword d_tag_utype;
  36 #endif
  37
  38 #ifndef RTLD_BOOTSTRAP
  39   if (dyn == NULL)
  40     return;
  41 #endif
  42
  43   info = l->l_info;
  44
  45   while (dyn->d_tag != DT_NULL)
  46     {
  47       if ((d_tag_utype) dyn->d_tag < DT_NUM)
  48         info[dyn->d_tag] = dyn;
  49       else if (dyn->d_tag >= DT_LOPROC &&
  50                dyn->d_tag < DT_LOPROC + DT_THISPROCNUM)
  51         {
  52           /* This does not violate the array bounds of l->l_info, but
  53              gcc 4.6 on sparc somehow does not see this.  */
  54           DIAG_PUSH_NEEDS_COMMENT;
  55           DIAG_IGNORE_NEEDS_COMMENT (4.6,
  56                                      "-Warray-bounds");
  57           info[dyn->d_tag - DT_LOPROC + DT_NUM] = dyn;
  58           DIAG_POP_NEEDS_COMMENT;
  59         }
  60       else if ((d_tag_utype) DT_VERSIONTAGIDX (dyn->d_tag) < DT_VERSIONTAGNUM)
  61         info[VERSYMIDX (dyn->d_tag)] = dyn;
  62       else if ((d_tag_utype) DT_EXTRATAGIDX (dyn->d_tag) < DT_EXTRANUM)
  63         info[DT_EXTRATAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
  64              + DT_VERSIONTAGNUM] = dyn;
  65       else if ((d_tag_utype) DT_VALTAGIDX (dyn->d_tag) < DT_VALNUM)
  66         info[DT_VALTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
  67              + DT_VERSIONTAGNUM + DT_EXTRANUM] = dyn;
  68       else if ((d_tag_utype) DT_ADDRTAGIDX (dyn->d_tag) < DT_ADDRNUM)
  69         info[DT_ADDRTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
  70              + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM] = dyn;
  71       ++dyn;
  72     }
  73
  74 #define DL_RO_DYN_TEMP_CNT      8
  75
  76 #ifndef DL_RO_DYN_SECTION
  77   /* Don't adjust .dynamic unnecessarily.  */
  78   if (l->l_addr != 0)
  79     {
  80       ElfW(Addr) l_addr = l->l_addr;
  81       int cnt = 0;
  82
  83 # define ADJUST_DYN_INFO(tag) \
  84       do                                                                      \
  85         if (info[tag] != NULL)                                                \
  86           {                                                                   \
  87             if (temp)                                                         \
  88               {                                                               \
  89                 temp[cnt].d_tag = info[tag]->d_tag;                           \
  90                 temp[cnt].d_un.d_ptr = info[tag]->d_un.d_ptr + l_addr;        \
  91                 info[tag] = temp + cnt++;                                     \
  92               }                                                               \
  93             else                                                              \
  94               info[tag]->d_un.d_ptr += l_addr;                                \
  95           }                                                                   \
  96       while (0)
  97
  98       ADJUST_DYN_INFO (DT_HASH);
  99       ADJUST_DYN_INFO (DT_PLTGOT);
 100       ADJUST_DYN_INFO (DT_STRTAB);
 101       ADJUST_DYN_INFO (DT_SYMTAB);
 102 # if ! ELF_MACHINE_NO_RELA
 103       ADJUST_DYN_INFO (DT_RELA);
 104 # endif
 105 # if ! ELF_MACHINE_NO_REL
 106       ADJUST_DYN_INFO (DT_REL);
 107 # endif
 108       ADJUST_DYN_INFO (DT_JMPREL);
 109       ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
 110       ADJUST_DYN_INFO (DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + DT_THISPROCNUM
 111                        + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM);
 112 # undef ADJUST_DYN_INFO
 113       assert (cnt <= DL_RO_DYN_TEMP_CNT);
 114     }
 115 #endif
 116   if (info[DT_PLTREL] != NULL)
 117     {
 118 #if ELF_MACHINE_NO_RELA
 119       assert (info[DT_PLTREL]->d_un.d_val == DT_REL);
 120 #elif ELF_MACHINE_NO_REL
 121       assert (info[DT_PLTREL]->d_un.d_val == DT_RELA);
 122 #else
 123       assert (info[DT_PLTREL]->d_un.d_val == DT_REL
 124               || info[DT_PLTREL]->d_un.d_val == DT_RELA);
 125 #endif
 126     }
 127 #if ! ELF_MACHINE_NO_RELA
 128   if (info[DT_RELA] != NULL)
 129     assert (info[DT_RELAENT]->d_un.d_val == sizeof (ElfW(Rela)));
 130 # endif
 131 # if ! ELF_MACHINE_NO_REL
 132   if (info[DT_REL] != NULL)
 133     assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
 134 #endif
 135 #ifdef RTLD_BOOTSTRAP
 136   /* Only the bind now flags are allowed.  */
 137   assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
 138           || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
 139   assert (info[DT_FLAGS] == NULL
 140           || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
 141   /* Flags must not be set for ld.so.  */
 142   assert (info[DT_RUNPATH] == NULL);
 143   assert (info[DT_RPATH] == NULL);
 144 #else
 145   if (info[DT_FLAGS] != NULL)
 146     {
 147       /* Flags are used.  Translate to the old form where available.
 148          Since these l_info entries are only tested for NULL pointers it
 149          is ok if they point to the DT_FLAGS entry.  */
 150       l->l_flags = info[DT_FLAGS]->d_un.d_val;
 151
 152       if (l->l_flags & DF_SYMBOLIC)
 153         info[DT_SYMBOLIC] = info[DT_FLAGS];
 154       if (l->l_flags & DF_TEXTREL)
 155         info[DT_TEXTREL] = info[DT_FLAGS];
 156       if (l->l_flags & DF_BIND_NOW)
 157         info[DT_BIND_NOW] = info[DT_FLAGS];
 158     }
 159   if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
 160     {
 161       l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
 162
 163       /* Only DT_1_SUPPORTED_MASK bits are supported, and we would like
 164          to assert this, but we can't. Users have been setting
 165          unsupported DF_1_* flags for a long time and glibc has ignored
 166          them. Therefore to avoid breaking existing applications the
 167          best we can do is add a warning during debugging with the
 168          intent of notifying the user of the problem.  */
 169       if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0)
 170           && l->l_flags_1 & ~DT_1_SUPPORTED_MASK)
 171         _dl_debug_printf ("\nWARNING: Unsupported flag value(s) of 0x%x in DT_FLAGS_1.\n",
 172                           l->l_flags_1 & ~DT_1_SUPPORTED_MASK);
 173
 174       if (l->l_flags_1 & DF_1_NOW)
 175         info[DT_BIND_NOW] = info[VERSYMIDX (DT_FLAGS_1)];
 176     }
 177   if (info[DT_RUNPATH] != NULL)
 178     /* If both RUNPATH and RPATH are given, the latter is ignored.  */
 179     info[DT_RPATH] = NULL;
 180 #endif
 181 }