elf/dl-iteratephdr.c

   1 /* Get loaded objects program headers.
   2    Copyright (C) 2001-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Jakub Jelinek <jakub@redhat.com>, 2001.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public License as
   8    published by the Free Software Foundation; either version 2.1 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If
  18    not, see <https://www.gnu.org/licenses/>.  */
  19
  20 #include <errno.h>
  21 #include <ldsodefs.h>
  22 #include <stddef.h>
  23 #include <libc-lock.h>
  24
  25 static void
  26 cancel_handler (void *arg __attribute__((unused)))
  27 {
  28   __rtld_lock_unlock_recursive (GL(dl_load_write_lock));
  29 }
  30
  31 int
  32 __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
  33                                     size_t size, void *data), void *data)
  34 {
  35   struct link_map *l;
  36   struct dl_phdr_info info;
  37   int ret = 0;
  38
  39   /* Make sure nobody modifies the list of loaded objects.  */
  40   __rtld_lock_lock_recursive (GL(dl_load_write_lock));
  41   __libc_cleanup_push (cancel_handler, NULL);
  42
  43   /* We have to determine the namespace of the caller since this determines
  44      which namespace is reported.  */
  45   size_t nloaded = GL(dl_ns)[0]._ns_nloaded;
  46   Lmid_t ns = 0;
  47 #ifdef SHARED
  48   const void *caller = RETURN_ADDRESS (0);
  49   for (Lmid_t cnt = GL(dl_nns) - 1; cnt > 0; --cnt)
  50     for (struct link_map *l = GL(dl_ns)[cnt]._ns_loaded; l; l = l->l_next)
  51       {
  52         /* We have to count the total number of loaded objects.  */
  53         nloaded += GL(dl_ns)[cnt]._ns_nloaded;
  54
  55         if (caller >= (const void *) l->l_map_start
  56             && caller < (const void *) l->l_map_end
  57             && (l->l_contiguous
  58                 || _dl_addr_inside_object (l, (ElfW(Addr)) caller)))
  59           ns = cnt;
  60       }
  61 #endif
  62
  63   for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
  64     {
  65       info.dlpi_addr = l->l_real->l_addr;
  66       info.dlpi_name = l->l_real->l_name;
  67       info.dlpi_phdr = l->l_real->l_phdr;
  68       info.dlpi_phnum = l->l_real->l_phnum;
  69       info.dlpi_adds = GL(dl_load_adds);
  70       info.dlpi_subs = GL(dl_load_adds) - nloaded;
  71       info.dlpi_tls_data = NULL;
  72       info.dlpi_tls_modid = l->l_real->l_tls_modid;
  73       if (info.dlpi_tls_modid != 0)
  74         info.dlpi_tls_data = GLRO(dl_tls_get_addr_soft) (l->l_real);
  75       ret = callback (&info, sizeof (struct dl_phdr_info), data);
  76       if (ret)
  77         break;
  78     }
  79
  80   /* Release the lock.  */
  81   __libc_cleanup_pop (0);
  82   __rtld_lock_unlock_recursive (GL(dl_load_write_lock));
  83
  84   return ret;
  85 }
  86 hidden_def (__dl_iterate_phdr)
  87
  88 weak_alias (__dl_iterate_phdr, dl_iterate_phdr);