nptl/pt-fork.c

   1 /* ABI compatibility for 'fork' 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 <unistd.h>
  21 #include <shlib-compat.h>
  22
  23 /* libpthread once had its own fork, though there was no apparent reason
  24    for it.  There is no use in having a separate symbol in libpthread, but
  25    the historical ABI requires it.  For static linking, there is no need to
  26    provide anything here--the libc version will be linked in.  For shared
  27    library ABI compatibility, there must be __fork and fork symbols in
  28    libpthread.so.
  29
  30    With an IFUNC resolver, it would be possible to avoid the
  31    indirection, but the IFUNC resolver might run before the
  32    __libc_fork symbol has been relocated, in which case the IFUNC
  33    resolver would not be able to provide the correct address.  */
  34
  35 #if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)
  36
  37 static pid_t __attribute__ ((used))
  38 fork_compat (void)
  39 {
  40   return __libc_fork ();
  41 }
  42
  43 strong_alias (fork_compat, fork_alias)
  44 compat_symbol (libpthread, fork_alias, fork, GLIBC_2_0);
  45
  46 strong_alias (fork_compat, __fork_alias)
  47 compat_symbol (libpthread, __fork_alias, __fork, GLIBC_2_0);
  48
  49 #endif