glibc/sysdeps/unix/sysv/linux/ptrace.c

/* Copyright (C) 1995, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include <errno.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <stdarg.h>

extern int __syscall_ptrace (int, pid_t, void *, void *);

int
ptrace (enum __ptrace_request request, ...)
{
  int res, ret;
  va_list ap;
  pid_t pid;
  void *addr, *data;

  va_start (ap, request);
  pid = va_arg (ap, pid_t);
  addr = va_arg (ap, void *);
  data = va_arg (ap, void *);
  va_end (ap);

  if (request > 0 && request < 4)
    data = &ret;

  res = __syscall_ptrace (request, pid, addr, data);

  if (res >= 0)
    {
      if (request > 0 && request < 4)
	{
	  errno = 0;
	  return ret;
	}
      return res;
    }

  errno = -res;
  return -1;
}