sysdeps/stub/dl-machine.h

   1 /* Machine-dependent ELF dynamic relocation inline functions.  Stub version.
   2 Copyright (C) 1995 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
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #define ELF_MACHINE_NAME "stub"
  21
  22 #include <assert.h>
  23 #include <string.h>
  24 #include <link.h>
  25
  26
  27 /* Return nonzero iff E_MACHINE is compatible with the running host.  */
  28 static inline int
  29 elf_machine_matches_host (Elf32_Half e_machine)
  30 {
  31   switch (e_machine)
  32     {
  33     default:
  34       return 0;
  35     }
  36 }
  37
  38
  39 /* Return the run-time address of the _GLOBAL_OFFSET_TABLE_.  */
  40 static inline Elf32_Addr *
  41 elf_machine_got (void)
  42 {
  43 #error "GOT not got"
  44 }
  45
  46
  47 /* Return the run-time load address of the shared object.  */
  48 static inline Elf32_Addr
  49 elf_machine_load_address (void)
  50 {
  51 #error "Where am I?"
  52 }
  53
  54 /* This can modify DYNAMIC_INFO to avoid relocating code in
  55    the functions above if they are doing bizarre magic.  */
  56 #define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) /* nothing */
  57
  58 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
  59    LOADADDR is the load address of the object; INFO is an array indexed
  60    by DT_* of the .dynamic section info.  */
  61
  62 static inline void
  63 elf_machine_rel (Elf32_Addr loadaddr, Elf32_Dyn *info[DT_NUM],
  64                  const Elf32_Rel *reloc,
  65                  Elf32_Addr sym_loadaddr, const Elf32_Sym *sym)
  66 {
  67   Elf32_Addr *const reloc_addr = (Elf32_Addr *) reloc->r_offset;
  68   const Elf32_Addr sym_value = sym_loadaddr + sym->st_value;
  69
  70   switch (ELF32_R_TYPE (reloc->r_info))
  71     {
  72     case R_MACHINE_COPY:
  73       memcpy (reloc_addr, (void *) sym_value, sym->st_size);
  74       break;
  75     default:
  76       assert (! "unexpected dynamic reloc type");
  77       break;
  78     }
  79 }
  80
  81
  82 static inline void
  83 elf_machine_rela (Elf32_Addr loadaddr, Elf32_Dyn *info[DT_NUM],
  84                   const Elf32_Rela *reloc,
  85                   Elf32_Addr sym_loadaddr, const Elf32_Sym *sym)
  86 {
  87   _dl_signal_error (0, "Elf32_Rela relocation requested -- unused on "
  88                     ELF_MACHINE_NAME);
  89 }
  90
  91
  92 /* Set up the loaded object described by L so its unrelocated PLT
  93    entries will jump to the on-demand fixup code in dl-runtime.c.  */
  94
  95 static inline void
  96 elf_machine_runtime_setup (struct link_map *l)
  97 {
  98   extern void _dl_runtime_resolve (Elf32_Word);
  99   /* The GOT entries for functions in the PLT have not yet been filled
 100      in.  Their initial contents will arrange when called to push an
 101      offset into the .rel.plt section, push _GLOBAL_OFFSET_TABLE_[1],
 102      and then jump to _GLOBAL_OFFSET_TABLE[2].  */
 103   Elf32_Addr *got = (Elf32_Addr *) l->l_info[DT_PLTGOT]->d_un.d_ptr;
 104   got[1] = (Elf32_Addr) l;      /* Identify this shared object.  */
 105   /* This function will get called to fix up the GOT entry indicated by
 106      the offset on the stack, and then jump to the resolved address.  */
 107   got[2] = (Elf32_Addr) &_dl_runtime_resolve;
 108 }
 109
 110
 111 /* Initial entry point code for the dynamic linker.
 112    The C function `_dl_start' is the real entry point;
 113    its return value is the user program's entry point.  */
 114
 115 #define RTLD_START #error need some startup code