Verification infrastructure

Similar model to enrollment.

examples/verify.c

@@ -85,10 +85,45 @@ struct fp_print_data *enroll(struct fp_dev *dev) {
 		return NULL;
 	}
 
-	printf("Enrollment completed!\n");
+	printf("Enrollment completed!\n\n");
 	return enrolled_print;
 }
 
+int verify(struct fp_dev *dev, struct fp_print_data *data)
+{
+	int r;
+
+	do {
+		sleep(1);
+		printf("\nScan your finger now.\n");
+		r = fp_verify_finger(dev, data);
+		if (r < 0) {
+			printf("verification failed with error %d :(\n", r);
+			return r;
+		}
+		switch (r) {
+		case FP_VERIFY_NO_MATCH:
+			printf("NO MATCH!\n");
+			return 0;
+		case FP_VERIFY_MATCH:
+			printf("MATCH!\n");
+			return 0;
+		case FP_VERIFY_RETRY:
+			printf("Scan didn't quite work. Please try again.\n");
+			break;
+		case FP_VERIFY_RETRY_TOO_SHORT:
+			printf("Swipe was too short, please try again.\n");
+			break;
+		case FP_VERIFY_RETRY_CENTER_FINGER:
+			printf("Please center your finger on the sensor and try again.\n");
+			break;
+		case FP_VERIFY_RETRY_REMOVE_FINGER:
+			printf("Please remove finger from the sensor and try again.\n");
+			break;
+		}
+	} while (1);
+}
+
 int main(void)
 {
 	int r;
@@ -128,7 +163,24 @@ int main(void)
 	if (!data)
 		goto out_close;
 
-	ret = 0;
+
+	printf("Normally we'd save that print to disk, and recall it at some "
+		"point later when we want to authenticate the user who just "
+		"enrolled. In the interests of demonstration, we'll authenticate "
+		"that user immediately.\n");
+
+	do {
+		char buffer[20];
+
+		verify(dev, data);
+		printf("Verify again? [Y/n]? ");
+		fgets(buffer, sizeof(buffer), stdin);
+		buffer[sizeof(buffer) - 1] = 0; /* null-terminate */
+		if (buffer[0] != '\n' && buffer[0] != 'y' && buffer[0] != 'Y')
+			break;
+	} while (1);
+
+	fp_print_data_free(data);
 out_close:
 	fp_dev_close(dev);
 	return ret;

libfprint/core.c

@@ -295,6 +295,39 @@ API_EXPORTED int fp_enroll_finger(struct fp_dev *dev,
 	return ret;
 }
 
+API_EXPORTED int fp_verify_finger(struct fp_dev *dev,
+	struct fp_print_data *enrolled_print)
+{
+	const struct fp_driver *drv = dev->drv;
+	int r;
+
+	if (!enrolled_print) {
+		fp_err("no print given");
+		return -EINVAL;
+	}
+
+	if (!drv->verify) {
+		fp_err("driver %s has no verify func", drv->name);
+		return -EINVAL;
+	}
+
+	if (!fpi_print_data_compatible(dev, enrolled_print)) {
+		fp_err("print is not compatible with device");
+		return -EINVAL;
+	}
+
+	fp_dbg("to be handled by %s", drv->name);
+	r = drv->verify(dev, enrolled_print);
+	if (r < 0)
+		fp_dbg("verify error %d", r);
+	else if (r == 0)
+		fp_dbg("result: no match");
+	else
+		fp_dbg("result: match");
+
+	return r;
+}
+
 API_EXPORTED int fp_init(void)
 {
 	fp_dbg("");

libfprint/fp_internal.h

@@ -98,6 +98,7 @@ struct fp_driver {
 	void (*exit)(struct fp_dev *dev);
 	int (*enroll)(struct fp_dev *dev, gboolean initial, int stage,
 		struct fp_print_data **print_data);
+	int (*verify)(struct fp_dev *dev, struct fp_print_data *data);
 };
 
 extern const struct fp_driver upekts_driver;

libfprint/fprint.h

@@ -54,6 +54,18 @@ enum fp_enroll_result {
 
 int fp_enroll_finger(struct fp_dev *dev, struct fp_print_data **print_data);
 
+/* Verification */
+enum fp_verify_result {
+	FP_VERIFY_NO_MATCH = 0,
+	FP_VERIFY_MATCH = 1,
+	FP_VERIFY_RETRY = FP_ENROLL_RETRY,
+	FP_VERIFY_RETRY_TOO_SHORT = FP_ENROLL_RETRY_TOO_SHORT,
+	FP_VERIFY_RETRY_CENTER_FINGER = FP_ENROLL_RETRY_CENTER_FINGER,
+	FP_VERIFY_RETRY_REMOVE_FINGER = FP_ENROLL_RETRY_REMOVE_FINGER,
+};
+
+int fp_verify_finger(struct fp_dev *dev, struct fp_print_data *enrolled_print);
+
 /* Data handling */
 void fp_print_data_free(struct fp_print_data *data);