Add sha256sum(1)

sha256sum.c

@@ -0,0 +1,49 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include "util.h"
+#include "crypt.h"
+#include "sha256.h"
+
+struct sha256 s;
+struct crypt_ops sha256_ops = {
+	sha256_init,
+	sha256_update,
+	sha256_sum,
+	&s,
+};
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [file...]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	FILE *fp;
+	uint8_t md[SHA256_DIGEST_LENGTH];
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc == 0) {
+		cryptsum(&sha256_ops, stdin, "<stdin>", md);
+		mdprint(md, "<stdin>", sizeof(md));
+	} else {
+		for (; argc > 0; argc--) {
+			if ((fp = fopen(*argv, "r")) == NULL)
+				eprintf("fopen %s:", *argv);
+			cryptsum(&sha256_ops, fp, *argv, md);
+			mdprint(md, *argv, sizeof(md));
+			fclose(fp);
+			argv++;
+		}
+	}
+
+	return 0;
+}