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- /* vim: set expandtab ts=4 sw=4: */
- /*
- * You may redistribute this program and/or modify it under the terms of
- * the GNU General Public License as published by the Free Software Foundation,
- * either version 3 of the License, or (at your option) any later version.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <https://www.gnu.org/licenses/>.
- */
- #define _GNU_SOURCE
- #include "crypto/random/seed/GetEntropyRandomSeed.h"
- #include "util/Identity.h"
- #include "util/Bits.h"
- #include <unistd.h>
- #include <errno.h>
- #include <sys/syscall.h>
- #if defined(__OPENBSD__)
- // just use the builtin getentropy
- #define getEntropy getentropy
- #else
- // getentropy is available in glibc >= 2.25
- // to avoid a whole bunch of edgecases we shim this anyway
- // we can drop this when every major system with SYS_getrandom
- // has getentropy in its libc
- static int getEntropy(void *buf, size_t buflen)
- {
- int ret;
- if (buflen > 256) {
- goto failure;
- }
- ret = syscall(SYS_getrandom, buf, buflen, 0);
- if (ret < 0) {
- return ret;
- }
- if ((size_t)ret == buflen) {
- return 0;
- }
- failure:
- errno = EIO;
- return -1;
- }
- #endif
- static int get(RandomSeed_t* randomSeed, uint64_t output[8])
- {
- if (getEntropy(output, 64) < 0) {
- return -1;
- } else {
- return 0;
- }
- }
- RandomSeed_t* GetEntropyRandomSeed_new(struct Allocator* alloc)
- {
- return Allocator_clone(alloc, (&(RandomSeed_t) {
- .get = get,
- .name = "getentropy(2)"
- }));
- }
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