1  /* Inline functions for dynamic linking.
       2     Copyright (C) 1995-2023 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  #ifndef _DL_STATIC_TLS_H
      20  #define _DL_STATIC_TLS_H
      21  
      22  /* This macro is used as a callback from elf_machine_rel{a,} when a
      23     static TLS reloc is about to be performed.  Since (in dl-load.c) we
      24     permit dynamic loading of objects that might use such relocs, we
      25     have to check whether each use is actually doable.  If the object
      26     whose TLS segment the reference resolves to was allocated space in
      27     the static TLS block at startup, then it's ok.  Otherwise, we make
      28     an attempt to allocate it in surplus space on the fly.  If that
      29     can't be done, we fall back to the error that DF_STATIC_TLS is
      30     intended to produce.  */
      31  #define HAVE_STATIC_TLS(map, sym_map)					\
      32      (__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET		\
      33  		       && ((sym_map)->l_tls_offset			\
      34  			   != FORCED_DYNAMIC_TLS_OFFSET), 1))
      35  
      36  #define CHECK_STATIC_TLS(map, sym_map)					\
      37      do {								\
      38        if (!HAVE_STATIC_TLS (map, sym_map))				\
      39  	_dl_allocate_static_tls (sym_map);				\
      40      } while (0)
      41  
      42  #define TRY_STATIC_TLS(map, sym_map)					\
      43      (__builtin_expect ((sym_map)->l_tls_offset				\
      44  		       != FORCED_DYNAMIC_TLS_OFFSET, 1)			\
      45       && (__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET, 1)	\
      46  	 || _dl_try_allocate_static_tls (sym_map, true) == 0))
      47  
      48  int _dl_try_allocate_static_tls (struct link_map *map, bool optional)
      49    attribute_hidden;
      50  
      51  #endif