1 files changed, 41 insertions, 0 deletions
diff --git a/util.h b/util.h
new file mode 100644
index 0000000..5c4a604
--- /dev/null
+++ b/util.h
@@ -0,0 +1,41 @@
+#ifndef UTIL_H
+#define UTIL_H
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "sha2.h"
+
+#define GRND_NONBLOCK 0x01
+#define GRND_RANDOM 0x02
+
+/* The pool size is fixed at 4096 bits since Linux 2.6. */
+#define RAND_POOL_SIZE 512
+/* SHA-256 */
+#define HASH_LEN 32
+/* The salt is the random data */
+#define SALT_LEN RAND_POOL_SIZE
+
+static inline bool streq(const char *s1, const char *s2) {
+    return !strcmp(s1, s2);
+}
+
+static inline ssize_t random_get(void *buf, size_t buflen, unsigned int flags) {
+    long rv = syscall(SYS_getrandom, buf, buflen, flags);
+    if (rv == -1 && errno == ENOSYS) {
+        fputs("getrandom returned ENOSYS. random-seed requires Linux 3.17", stderr);
+        exit(1);
+    }
+    return rv;
+}
+
+size_t hex2mem(unsigned char *dest, size_t size, const char *src);
+void mem2hex(char *dest, const void *src, size_t size);
+void hash(const unsigned char salt[static SALT_LEN], unsigned char *out, const void *in, size_t size);
+bool hash_match(const unsigned char digest[static HASH_LEN], const char *arg);
+
+#endif