/* Implementation of the getrandom system call.

   Copyright (C) 2016-2018 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 Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <sys/random.h>

#include <errno.h>

#include <unistd.h>

#include <sysdep-cancel.h>

#ifdef __NR_getrandom

/* Write up to LENGTH bytes of randomness starting at BUFFER.

   Return the number of bytes written, or -1 on error.  */

ssize_t

getrandom (void *buffer, size_t length, unsigned int flags)

{

  return SYSCALL_CANCEL (getrandom, buffer, length, flags);

}

#else

/* Always provide a definition, even if the kernel headers lack the

   system call number. */

ssize_t

getrandom (void *buffer, size_t length, unsigned int flags)

{

  /* Ideally, we would add a cancellation point here, but we currently

     cannot do so inside libc.  */

  __set_errno (ENOSYS);

  return -1;

}

#endif