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

46 lines
1.6 KiB
C

/* Implementation of the getrandom system call.
Copyright (C) 2016-2020 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
<https://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
libc_hidden_def (__getrandom)
weak_alias (__getrandom, getrandom)