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/* Fill a buffer with random bytes.
Copyright 2020-2021 Free Software Foundation, Inc.
This file 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 3 of the
License, or (at your option) any later version.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert. */
#include <config.h>
#include <unistd.h>
#include <errno.h>
#include <sys/random.h>
/* Overwrite BUFFER with random data. BUFFER contains LENGTH bytes.
LENGTH must be at most 256. Return 0 on success, -1 (setting
errno) on failure. */
int
getentropy (void *buffer, size_t length)
{
char *buf = buffer;
if (length <= 256)
for (;;)
{
ssize_t bytes;
if (length == 0)
return 0;
while ((bytes = getrandom (buf, length, 0)) < 0)
if (errno != EINTR)
return -1;
if (bytes == 0)
break;
buf += bytes;
length -= bytes;
}
errno = EIO;
return -1;
}
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