support/xclone.c

   1 /* Auxiliary functions to issue the clone syscall.
   2    Copyright (C) 2021 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 #ifdef __linux__
  20 # include <support/check.h>
  21 # include <stackinfo.h>  /* For _STACK_GROWS_{UP,DOWN}.  */
  22 # include <xsched.h>
  23
  24 pid_t
  25 xclone (int (*fn) (void *arg), void *arg, void *stack, size_t stack_size,
  26         int flags)
  27 {
  28   pid_t r = -1;
  29
  30 # ifdef __ia64__
  31   extern int __clone2 (int (*fn) (void *arg), void *stack, size_t stack_size,
  32                        int flags, void *arg, ...);
  33   r = __clone2 (fn, stack, stack_size, flags, arg, /* ptid */ NULL,
  34                 /* tls */ NULL, /* ctid  */ NULL);
  35 # else
  36 #  if _STACK_GROWS_DOWN
  37   r = clone (fn, stack + stack_size, flags, arg, /* ptid */ NULL,
  38              /* tls */ NULL, /* ctid */  NULL);
  39 #  elif _STACK_GROWS_UP
  40   r = clone (fn, stack, flags, arg, /* ptid */ NULL, /* tls */ NULL, NULL);
  41 #  endif
  42 # endif
  43
  44   if (r < 0)
  45     FAIL_EXIT1 ("clone: %m");
  46
  47   return r;
  48 }
  49 #endif