nptl/pt-system.c

   1 /* ABI compatibility for 'system' symbol in libpthread ABI.
   2    Copyright (C) 2002-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   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
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the 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; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <stdlib.h>
  21 #include <shlib-compat.h>
  22
  23 /* libpthread once had its own 'system', though there was no apparent
  24    reason for it.  There is no use in having a separate symbol in
  25    libpthread, but the historical ABI requires it.  For static linking,
  26    there is no need to provide anything here--the libc version will be
  27    linked in.  For shared library ABI compatibility, there must be a
  28    'system' symbol in libpthread.so.
  29
  30    With an IFUNC resolver, it would be possible to avoid the indirection,
  31    but the IFUNC resolver might run before the __libc_system symbol has
  32    been relocated, in which case the IFUNC resolver would not be able to
  33    provide the correct address.  */
  34
  35 #if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)
  36
  37 static int __attribute__ ((used))
  38 system_compat (const char *line)
  39 {
  40   return __libc_system (line);
  41 }
  42 strong_alias (system_compat, system_alias)
  43 compat_symbol (libpthread, system_alias, system, GLIBC_2_0);
  44
  45 #endif