Update some demos

demos/otp/otp-setup.c

@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libgen.h>
+#include <openssl/err.h>
+#include <openssl/bio.h>
+#include <openssl/rand.h>
+#include <openssl/is_gmssl.h>
+
+int main(int argc, char **argv)
+{
+	BIO *bio = NULL;
+	unsigned char key[32];
+
+	if (!RAND_bytes(key, sizeof(key))) {
+		ERR_print_errors_fp(stderr);
+		return -1;
+	}
+
+	if (!(bio = BIO_new_file(".otp_secret", "w"))) {
+		ERR_print_errors_fp(stderr);
+		return -1;
+	}
+
+	if (BIO_write(bio, key, sizeof(key)) != sizeof(key)) {
+		ERR_print_errors_fp(stderr);
+		BIO_free(bio);
+		return -1;
+	}
+
+	printf("generate OTP seed in '.otp_secret'\n");
+
+	BIO_free(bio);
+	OPENSSL_cleanse(key, sizeof(key));
+
+	return 0;
+}

demos/otp/otp.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libgen.h>
+#include <openssl/err.h>
+#include <openssl/otp.h>
+#include <openssl/objects.h>
+#include <openssl/is_gmssl.h>
+
+int main(int argc, char **argv)
+{
+	char *prog = basename(argv[0]);
+	BIO *bio = NULL;
+	OTP_PARAMS params;
+	unsigned char key[32] = {0};
+	unsigned char event[] = "this is a fixed value";
+	unsigned int otp;
+
+	params.type = NID_sm3;
+	params.te = 1;
+	params.option = NULL;
+	params.option_size = 0;
+	params.otp_digits = 6;
+
+	if (!(bio = BIO_new_file(".otp_secret", "r"))) {
+		ERR_print_errors_fp(stderr);
+		return -1;
+	}
+	if (BIO_read(bio, key, sizeof(key)) != sizeof(key)) {
+		ERR_print_errors_fp(stderr);
+		BIO_free(bio);
+		return -1;
+	}
+	BIO_free(bio);
+
+	if (!OTP_generate(&params, event, sizeof(event), &otp, key, sizeof(key))) {
+		ERR_print_errors_fp(stderr);
+		return -1;
+	}
+
+	printf("%06u\n", otp);
+	return 0;
+}