elf/dl-iteratephdr.c

   1 /* Get loaded objects program headers.
   2    Copyright (C) 2001-2024 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 License as
   7    published by the Free Software Foundation; either version 2.1 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    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; see the file COPYING.LIB.  If
  17    not, see <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <ldsodefs.h>
  21 #include <stddef.h>
  22 #include <libc-lock.h>
  23
  24 static void
  25 cancel_handler (void *arg __attribute__((unused)))
  26 {
  27   __rtld_lock_unlock_recursive (GL(dl_load_write_lock));
  28 }
  29
  30 int
  31 __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
  32                                     size_t size, void *data), void *data)
  33 {
  34   struct link_map *l;
  35   struct dl_phdr_info info;
  36   int ret = 0;
  37
  38   /* Make sure nobody modifies the list of loaded objects.  */
  39   __rtld_lock_lock_recursive (GL(dl_load_write_lock));
  40   __libc_cleanup_push (cancel_handler, NULL);
  41
  42   /* We have to determine the namespace of the caller since this determines
  43      which namespace is reported.  */
  44   size_t nloaded = GL(dl_ns)[0]._ns_nloaded;
  45   Lmid_t ns = 0;
  46 #ifdef SHARED
  47   const void *caller = RETURN_ADDRESS (0);
  48   for (Lmid_t cnt = GL(dl_nns) - 1; cnt > 0; --cnt)
  49     for (struct link_map *l = GL(dl_ns)[cnt]._ns_loaded; l; l = l->l_next)
  50       {
  51         /* We have to count the total number of loaded objects.  */
  52         nloaded += GL(dl_ns)[cnt]._ns_nloaded;
  53
  54         if (caller >= (const void *) l->l_map_start
  55             && caller < (const void *) l->l_map_end
  56             && (l->l_contiguous
  57                 || _dl_addr_inside_object (l, (ElfW(Addr)) caller)))
  58           ns = cnt;
  59       }
  60 #endif
  61
  62   for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
  63     {
  64       info.dlpi_addr = l->l_real->l_addr;
  65       info.dlpi_name = l->l_real->l_name;
  66       info.dlpi_phdr = l->l_real->l_phdr;
  67       info.dlpi_phnum = l->l_real->l_phnum;
  68       info.dlpi_adds = GL(dl_load_adds);
  69       info.dlpi_subs = GL(dl_load_adds) - nloaded;
  70       info.dlpi_tls_data = NULL;
  71       info.dlpi_tls_modid = l->l_real->l_tls_modid;
  72       if (info.dlpi_tls_modid != 0)
  73         info.dlpi_tls_data = GLRO(dl_tls_get_addr_soft) (l->l_real);
  74       ret = callback (&info, sizeof (struct dl_phdr_info), data);
  75       if (ret)
  76         break;
  77     }
  78
  79   /* Release the lock.  */
  80   __libc_cleanup_pop (0);
  81   __rtld_lock_unlock_recursive (GL(dl_load_write_lock));
  82
  83   return ret;
  84 }
  85 hidden_def (__dl_iterate_phdr)
  86
  87 weak_alias (__dl_iterate_phdr, dl_iterate_phdr);