nptl/sysdeps/unix/sysv/linux/i386/vfork.S

   1 /* Copyright (C) 1999,2002,2004,2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 /* We want an #include_next, but we are the main source file.
  19    So, #include ourselves and in that incarnation we can use #include_next.  */
  20 #ifndef INCLUDED_SELF
  21 # define INCLUDED_SELF
  22 # include <vfork.S>
  23 #else
  24
  25 # include <tcb-offsets.h>
  26
  27 /* Save the PID value.  */
  28 # define SAVE_PID \
  29         movl    %gs:PID, %edx;                                                \
  30         movl    %edx, %eax;                                                   \
  31         negl    %eax;                                                         \
  32         jne     1f;                                                           \
  33         movl    $0x80000000, %eax;                                            \
  34 1:      movl    %eax, %gs:PID
  35
  36 /* Restore the old PID value in the parent.  */
  37 # define RESTORE_PID \
  38         testl   %eax, %eax;                                                   \
  39         je      1f;                                                           \
  40         movl    %edx, %gs:PID;                                                \
  41 1:
  42
  43 # include_next <vfork.S>
  44 #endif