elf/rtld_static_init.c

   1 /* Partial initialization of ld.so loaded via static dlopen.
   2    Copyright (C) 2021 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20
  21 /* Very special case: This object is built into the static libc, but
  22    must know the layout of _rtld_global_ro.  */
  23 #define SHARED
  24 #include <ldsodefs.h>
  25
  26 #include <rtld_static_init.h>
  27
  28 static const struct dlfcn_hook _dlfcn_hook =
  29   {
  30     .dlopen = __dlopen,
  31     .dlclose = __dlclose,
  32     .dlsym = __dlsym,
  33     .dlvsym = __dlvsym,
  34     .dlerror = __dlerror,
  35     .dladdr = __dladdr,
  36     .dladdr1 = __dladdr1,
  37     .dlinfo = __dlinfo,
  38     .dlmopen = __dlmopen,
  39     .libc_dlopen_mode = __libc_dlopen_mode,
  40     .libc_dlsym = __libc_dlsym,
  41     .libc_dlvsym = __libc_dlvsym,
  42     .libc_dlclose = __libc_dlclose,
  43   };
  44
  45 void
  46 __rtld_static_init (struct link_map *map)
  47 {
  48   const ElfW(Sym) *sym
  49     = _dl_lookup_direct (map, "_rtld_global_ro",
  50                          0x9f28436a, /* dl_new_hash output.  */
  51                          "GLIBC_PRIVATE",
  52                          0x0963cf85); /* _dl_elf_hash output.  */
  53   assert (sym != NULL);
  54   struct rtld_global_ro *dl = DL_SYMBOL_ADDRESS (map, sym);
  55
  56   /* Perform partial initialization here.  Note that this runs before
  57      ld.so is relocated, so only members initialized without
  58      relocations can be written here.  */
  59 #ifdef HAVE_AUX_VECTOR
  60   extern __typeof (dl->_dl_auxv) _dl_auxv attribute_hidden;
  61   dl->_dl_auxv = _dl_auxv;
  62   extern __typeof (dl->_dl_clktck) _dl_clktck attribute_hidden;
  63   dl->_dl_clktck = _dl_clktck;
  64 #endif
  65   dl->_dl_dlfcn_hook = &_dlfcn_hook;
  66   extern __typeof (dl->_dl_hwcap) _dl_hwcap attribute_hidden;
  67   dl->_dl_hwcap = _dl_hwcap;
  68   extern __typeof (dl->_dl_hwcap2) _dl_hwcap2 attribute_hidden;
  69   dl->_dl_hwcap2 = _dl_hwcap2;
  70   extern __typeof (dl->_dl_minsigstacksize) _dl_minsigstacksize
  71     attribute_hidden;
  72   dl->_dl_minsigstacksize = _dl_minsigstacksize;
  73   extern __typeof (dl->_dl_pagesize) _dl_pagesize attribute_hidden;
  74   dl->_dl_pagesize = _dl_pagesize;
  75   extern __typeof (dl->_dl_tls_static_align) _dl_tls_static_align
  76     attribute_hidden;
  77   dl->_dl_tls_static_align = _dl_tls_static_align;
  78   extern __typeof (dl->_dl_tls_static_size) _dl_tls_static_size
  79     attribute_hidden;
  80   dl->_dl_tls_static_size = _dl_tls_static_size;
  81
  82   __rtld_static_init_arch (map, dl);
  83 }