1/* Implementation of the getrandom system call.
2 Copyright (C) 2016-2019 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 <http://www.gnu.org/licenses/>. */
18
19#include <sys/random.h>
20#include <errno.h>
21#include <unistd.h>
22#include <sysdep-cancel.h>
23
24#ifdef __NR_getrandom
25/* Write up to LENGTH bytes of randomness starting at BUFFER.
26 Return the number of bytes written, or -1 on error. */
27ssize_t
28getrandom (void *buffer, size_t length, unsigned int flags)
29{
30 return SYSCALL_CANCEL (getrandom, buffer, length, flags);
31}
32#else
33/* Always provide a definition, even if the kernel headers lack the
34 system call number. */
35ssize_t
36getrandom (void *buffer, size_t length, unsigned int flags)
37{
38 /* Ideally, we would add a cancellation point here, but we currently
39 cannot do so inside libc. */
40 __set_errno (ENOSYS);
41 return -1;
42}
43#endif
44