1 files changed, 82 insertions, 0 deletions
diff --git a/util/libreboot-utils/lib/num.c b/util/libreboot-utils/lib/num.c
new file mode 100644
index 00000000..79d6b409
--- /dev/null
+++ b/util/libreboot-utils/lib/num.c
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: MIT
+ * Copyright (c) 2026 Leah Rowe <leah@libreboot.org>
+ *
+ * Non-randomisation-related numerical functions.
+ * For rand functions, see: rand.c
+ */
+
+#ifdef __OpenBSD__
+#include <sys/param.h>
+#endif
+#include <sys/types.h>
+
+#include <errno.h>
+#if !((defined(__OpenBSD__) && (OpenBSD) >= 201) || \
+    defined(__FreeBSD__) || \
+    defined(__NetBSD__) || defined(__APPLE__))
+#include <fcntl.h> /* if not arc4random: /dev/urandom */
+#endif
+#include <limits.h>
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "../include/common.h"
+
+unsigned short
+hextonum(char ch_s)
+{
+	int saved_errno = errno;
+
+	unsigned char ch;
+	size_t rval;
+
+	ch = (unsigned char)ch_s;
+
+	if ((unsigned int)(ch - '0') <= 9) {
+
+		rval = ch - '0';
+		goto hextonum_success;
+	}
+
+	ch |= 0x20;
+
+	if ((unsigned int)(ch - 'a') <= 5) {
+
+		rval = ch - 'a' + 10;
+		goto hextonum_success;
+	}
+
+	if (ch == '?' || ch == 'x') {
+
+		rset(&rval, sizeof(rval));
+
+		goto hextonum_success;
+	}
+
+	goto err_hextonum;
+
+hextonum_success:
+
+	errno = saved_errno;
+	return (unsigned short)rval & 0xf;
+
+err_hextonum:
+
+	if (errno == saved_errno)
+		errno = EINVAL;
+	else
+		return 17; /* 17 indicates getrandom/urandom fail */
+
+	return 16; /* invalid character */
+
+	/* caller just checks >15. */
+}
+
+void
+check_bin(size_t a, const char *a_name)
+{
+	if (a > 1)
+		err_no_cleanup(0, EINVAL, "%s must be 0 or 1, but is %lu",
+		    a_name, (size_t)a);
+}