Add empty reader implementation that always succeeds

Signed-off-by: Vyacheslav Yurkov <uvv.mail@gmail.com>

Author: UVV-gh

src/libopensc/Makefile.am

@@ -35,7 +35,7 @@ libopensc_la_SOURCES_BASE = \
 	\
 	muscle.c muscle-filesystem.c \
 	\
-	ctbcs.c reader-ctapi.c reader-pcsc.c reader-openct.c reader-tr03119.c \
+	ctbcs.c reader-ctapi.c reader-pcsc.c reader-openct.c reader-tr03119.c reader-empty.c \
 	\
 	card-setcos.c card-flex.c \
 	card-cardos.c card-cardos-common.c card-tcos.c card-default.c \
@@ -117,7 +117,7 @@ TIDY_FILES = \
 	\
 	muscle.c muscle-filesystem.c \
 	\
-	ctbcs.c reader-ctapi.c reader-pcsc.c reader-openct.c reader-tr03119.c \
+	ctbcs.c reader-ctapi.c reader-pcsc.c reader-openct.c reader-tr03119.c reader-empty.c \
 	\
 	card-setcos.c card-flex.c \
 	card-cardos.c card-tcos.c card-default.c \

src/libopensc/ctx.c

@@ -1029,6 +1029,8 @@ int sc_context_create(sc_context_t **ctx_out, const sc_context_param_t *parm)
 	ctx->reader_driver = sc_get_ctapi_driver();
 #elif defined(ENABLE_OPENCT)
 	ctx->reader_driver = sc_get_openct_driver();
+#else
+	ctx->reader_driver = sc_get_empty_driver();
 #endif
 
 	r = ctx->reader_driver->ops->init(ctx);

src/libopensc/internal.h

@@ -295,6 +295,7 @@ extern struct sc_reader_driver *sc_get_pcsc_driver(void);
 extern struct sc_reader_driver *sc_get_ctapi_driver(void);
 extern struct sc_reader_driver *sc_get_openct_driver(void);
 extern struct sc_reader_driver *sc_get_cryptotokenkit_driver(void);
+extern struct sc_reader_driver *sc_get_empty_driver(void);
 
 #ifdef __cplusplus
 }

src/libopensc/reader-empty.c

@@ -0,0 +1,159 @@
+/*
+ * reader-none.c: Reader driver stub with no functionality
+ *
+ * Copyright (C) 2026  Vyacheslav Yurkov <uvv.mail@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "internal.h"
+
+static int
+empty_transmit(sc_reader_t *reader, sc_apdu_t *apdu)
+{
+	return 0;
+}
+
+static int
+empty_detect_card_presence(sc_reader_t *reader)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_connect(sc_reader_t *reader)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_disconnect(sc_reader_t * reader)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_pin_cmd(sc_reader_t *reader, struct sc_pin_cmd_data *data)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_lock(sc_reader_t *reader)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_unlock(sc_reader_t *reader)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_release(sc_reader_t *reader)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_reset(sc_reader_t *reader, int do_cold_reset)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_cancel(sc_context_t *ctx)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_init(sc_context_t *ctx)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_finish(sc_context_t *ctx)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_detect_readers(sc_context_t *ctx)
+{
+	return SC_SUCCESS;
+}
+
+static int
+empty_wait_for_event(sc_context_t *ctx, unsigned int event_mask, sc_reader_t **event_reader, unsigned int *event,
+		int timeout, void **reader_states)
+{
+	return SC_SUCCESS;
+}
+
+int
+empty_perform_pace(struct sc_reader *reader, void *input_pace, void *output_pace)
+{
+	return SC_SUCCESS;
+}
+
+int
+empty_use_reader(sc_context_t *ctx, void *empty_context_handle, void *empty_card_handle)
+{
+	return SC_SUCCESS;
+}
+
+static struct sc_reader_operations empty_ops;
+
+static struct sc_reader_driver empty_drv = {
+	"Empty reader",
+	"none",
+	&empty_ops,
+	NULL
+};
+
+struct sc_reader_driver *
+sc_get_empty_driver(void)
+{
+	empty_ops.init = empty_init;
+	empty_ops.finish = empty_finish;
+	empty_ops.detect_readers = empty_detect_readers;
+	empty_ops.transmit = empty_transmit;
+	empty_ops.detect_card_presence = empty_detect_card_presence;
+	empty_ops.lock = empty_lock;
+	empty_ops.unlock = empty_unlock;
+	empty_ops.release = empty_release;
+	empty_ops.connect = empty_connect;
+	empty_ops.disconnect = empty_disconnect;
+	empty_ops.perform_verify = empty_pin_cmd;
+	empty_ops.wait_for_event = empty_wait_for_event;
+	empty_ops.cancel = empty_cancel;
+	empty_ops.reset = empty_reset;
+	empty_ops.use_reader = empty_use_reader;
+	empty_ops.perform_pace = empty_perform_pace;
+
+	return &empty_drv;
+}