1 files changed, 146 insertions, 0 deletions
diff --git a/util/libreboot-utils/lib/string.c b/util/libreboot-utils/lib/string.c
new file mode 100644
index 00000000..cb37c1ba
--- /dev/null
+++ b/util/libreboot-utils/lib/string.c
@@ -0,0 +1,146 @@
+/* SPDX-License-Identifier: MIT
+ * Copyright (c) 2026 Leah Rowe <leah@libreboot.org>
+ *
+ * String functions
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "../include/common.h"
+
+/* scmp() - strict string comparison
+ *
+ * strict string comparison
+ * similar to strncmp, but null and
+ * unterminated inputs do not produce
+ * a return value; on error, errno is
+ * set and -1 is returned.
+ *
+ * the real return value is stored in
+ * the 4th argument by pointer.
+ *
+ * the value at rval pointer is set,
+ * only upon success. callers should
+ * check the return value accordingly.
+ */
+
+int
+scmp(const char *a,
+    const char *b,
+    size_t maxlen,
+    int *rval)
+{
+	size_t ch;
+	unsigned char ac;
+	unsigned char bc;
+
+	if (a == NULL ||
+	    b == NULL ||
+	    rval == NULL) {
+
+		errno = EFAULT;
+		return -1;
+	}
+
+	for (ch = 0; ch < maxlen; ch++) {
+
+		ac = (unsigned char)a[ch];
+		bc = (unsigned char)b[ch];
+
+		if (ac != bc) {
+			*rval = ac - bc;
+			return 0;
+		}
+
+		if (ac == '\0') {
+			*rval = 0;
+			return 0;
+		}
+	}
+
+	/* block unterminated strings */
+	errno = EFAULT;
+	return -1;
+}
+
+/* slen() - strict strict length
+ *
+ * strict string length calculation
+ * similar to strnlen, but null and
+ * unterminated inputs do not produce
+ * a return value; on error, errno is
+ * set and -1 is returned.
+ *
+ * the real return value is stored in
+ * the 3rd argument by pointer.
+ *
+ * the value at rval pointer is set,
+ * only upon success. callers should
+ * check the return value accordingly.
+ */
+
+int
+slen(const char *s,
+    size_t maxlen,
+    size_t *rval)
+{
+	size_t ch;
+
+	if (s == NULL ||
+	    rval == NULL) {
+
+		errno = EFAULT;
+		return -1;
+	}
+
+	for (ch = 0;
+	    ch < maxlen && s[ch] != '\0';
+	    ch++);
+
+	if (ch == maxlen) {
+		/* unterminated */
+		errno = EFAULT;
+		return -1;
+	}
+
+	*rval = ch;
+	return 0;
+}
+
+/* the one for nvmutil state is in state.c */
+/* this one just exits */
+void
+err_no_cleanup(int nvm_errval, const char *msg, ...)
+{
+	va_list args;
+
+#if defined(__OpenBSD__) && defined(OpenBSD)
+#if (OpenBSD) >= 509
+	if (pledge("stdio", NULL) == -1)
+		fprintf(stderr, "pledge failure during exit");
+#endif
+#endif
+
+	if (!errno)
+		errno = ECANCELED;
+
+	fprintf(stderr, "nvmutil: ");
+
+	va_start(args, msg);
+	vfprintf(stderr, msg, args);
+	va_end(args);
+
+	fprintf(stderr, ": %s\n", strerror(errno));
+
+	exit(EXIT_FAILURE);
+}
+