1  /* Support for relocating static PIE.
       2     Copyright (C) 2017-2023 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  #if ENABLE_STATIC_PIE
      20  /* Mark symbols hidden in static PIE for early self relocation to work.  */
      21  # pragma GCC visibility push(hidden)
      22  #include <assert.h>
      23  #include <unistd.h>
      24  #include <ldsodefs.h>
      25  
      26  #include <dl-machine.h>
      27  #include <dl-debug.h>
      28  
      29  #define RESOLVE_MAP(map, scope, sym, version, flags) map
      30  #include "dynamic-link.h"
      31  #include "get-dynamic-info.h"
      32  
      33  /* Relocate static executable with PIE.  */
      34  
      35  void
      36  _dl_relocate_static_pie (void)
      37  {
      38    struct link_map *main_map = _dl_get_dl_main_map ();
      39  
      40    /* Figure out the run-time load address of static PIE.  */
      41    main_map->l_addr = elf_machine_load_address ();
      42  
      43    /* Read our own dynamic section and fill in the info array.  */
      44    main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ());
      45  
      46    const ElfW(Phdr) *ph, *phdr = GL(dl_phdr);
      47    size_t phnum = GL(dl_phnum);
      48    for (ph = phdr; ph < &phdr[phnum]; ++ph)
      49      if (ph->p_type == PT_DYNAMIC)
      50        {
      51  	main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
      52  	break;
      53        }
      54  
      55    elf_get_dynamic_info (main_map, false, true);
      56  
      57  # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
      58    ELF_MACHINE_BEFORE_RTLD_RELOC (main_map, main_map->l_info);
      59  # endif
      60  
      61    /* Relocate ourselves so we can do normal function calls and
      62       data access using the global offset table.  */
      63    ELF_DYNAMIC_RELOCATE (main_map, NULL, 0, 0, 0);
      64    main_map->l_relocated = 1;
      65  
      66    /* Initialize _r_debug_extended.  */
      67    struct r_debug *r = _dl_debug_initialize (0, LM_ID_BASE);
      68    r->r_state = RT_CONSISTENT;
      69  
      70    /* Set up debugging before the debugger is notified for the first
      71       time.  */
      72    elf_setup_debug_entry (main_map, r);
      73  }
      74  #endif