fxlink: add --sockin and --sockout options to fxlink -i

fxlink/fxlink.h

@@ -8,6 +8,7 @@
 #pragma once
 #include <fxlink/filter.h>
 #include <libusb.h>
+#include <sys/un.h>
 
 /* Global and command-line options. */
 struct fxlink_options {
@@ -33,7 +34,9 @@ int main_send(struct fxlink_filter *filter, delay_t *delay, char **files,
 
 /* Main function for -i */
 int main_interactive(struct fxlink_filter *filter, delay_t *delay,
-	libusb_context *context);
+	libusb_context *context,
+	const struct sockaddr_un *sockin_addr,
+	const struct sockaddr_un *sockout_addr);
 
 /* Main function for -t */
 int main_tui_interactive(libusb_context *context);

fxlink/main.c

@@ -13,6 +13,8 @@
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <sys/socket.h>
+#include <sys/un.h>
 #include <errno.h>
 #include <locale.h>
 
@@ -47,6 +49,10 @@ static const char *help_string =
 "  --fxlink-log[=FILE] -i: Append fxlink text messages to FILE. Without\n"
 "                          argument, a unique name is generated.\n"
 "  -r, --repeat        -i: Reconnect if the calc disconnects (implies -w)\n"
+"  --sockin=SOCKET     -i: Send messages read from the datagram Unix socket\n"
+"                          SOCKET to the calculator as fxlink text messages.\n"
+"  --sockout=SOCKET    -i: Send fxlink text messages read from the calculator\n"
+"                          to the datagram Unix socket SOCKET.\n"
 "  --folder=FOLDER     -s: Select destination folder for files\n"
 "\n"
 "Device filters:\n"
@@ -69,6 +75,8 @@ int main(int argc, char **argv)
 	struct fxlink_filter *filter = NULL;
 	bool repeat = false;
 	char *outfolder = NULL;
+	struct sockaddr_un sockin_addr = { AF_UNSPEC };
+	struct sockaddr_un sockout_addr = { AF_UNSPEC };
 
 	options.log_file = NULL;
 	options.verbose = false;
@@ -79,7 +87,7 @@ int main(int argc, char **argv)
 	// Command-line argument parsing
 	//---
 
-	enum { LIBUSB_LOG=1, LOG_TO_FILE=2, OUT_FOLDER=3 };
+	enum { LIBUSB_LOG=1, LOG_TO_FILE=2, OUT_FOLDER=3, SOCKIN=4, SOCKOUT=5 };
 	const struct option longs[] = {
 		{ "help",        no_argument,       NULL, 'h' },
 		{ "list",        no_argument,       NULL, 'l' },
@@ -93,6 +101,8 @@ int main(int argc, char **argv)
 		{ "repeat",      no_argument,       NULL, 'r' },
 		{ "verbose",     no_argument,       NULL, 'v' },
 		{ "folder",      required_argument, NULL, OUT_FOLDER },
+		{ "sockin",      required_argument, NULL, SOCKIN },
+		{ "sockout",     required_argument, NULL, SOCKOUT },
 		/* Deprecated options ignored for compatibility: */
 		{ "quiet",       no_argument,       NULL, 'q' },
 		{ "unmount",     no_argument,       NULL, 'u' },
@@ -171,6 +181,14 @@ int main(int argc, char **argv)
 	case OUT_FOLDER:
 		outfolder = strdup(optarg);
 		break;
+	case SOCKIN:
+		sockin_addr.sun_family = AF_UNIX;
+		strncpy(sockin_addr.sun_path, optarg, sizeof(sockin_addr.sun_path) - 1);
+		break;
+	case SOCKOUT:
+		sockout_addr.sun_family = AF_UNIX;
+		strncpy(sockout_addr.sun_path, optarg, sizeof(sockout_addr.sun_path) - 1);
+		break;
 	case '?':
 		error = 1;
 	}
@@ -232,7 +250,9 @@ int main(int argc, char **argv)
 	}
 	else if(mode == 'i') {
 		do {
-			rc = main_interactive(filter, &delay, context);
+			rc = main_interactive(filter, &delay, context,
+					      sockin_addr.sun_family == AF_UNSPEC ? NULL : &sockin_addr,
+					      sockout_addr.sun_family == AF_UNSPEC ? NULL : &sockout_addr);
 		}
 		while(repeat);
 	}

fxlink/modes/interactive.c

@@ -15,9 +15,15 @@
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
 
 static void handle_new_message(struct fxlink_device *fdev,
-	struct fxlink_message *msg)
+	struct fxlink_message *msg,
+	int socket_fd,
+	const struct sockaddr_un *sockout_addr)
 {
 	char const *path = ".";
 
@@ -41,6 +47,11 @@ static void handle_new_message(struct fxlink_device *fdev,
 	if(fxlink_message_is_fxlink_text(msg)) {
 		char const *str = msg->data;
 
+		if(socket_fd >= 0 && sockout_addr != NULL &&
+		   sendto(socket_fd, msg->data, msg->size, 0, sockout_addr, sizeof(*sockout_addr)) < 0) {
+			perror("sendto");
+		}
+
 		if(options.verbose)
 			printf("------------------\n");
 		fwrite(str, 1, msg->size, stdout);
@@ -95,8 +106,77 @@ static void handle_new_message(struct fxlink_device *fdev,
     free(filename);
 }
 
+static int setup_socket(const struct sockaddr_un *sockin_addr,
+	const struct sockaddr_un *sockout_addr)
+{
+	if(sockin_addr == NULL && sockout_addr == NULL) {
+		/* -1 is used to indicate that no fd were opened but it's not a fatal error */
+		return -1;
+	}
+
+	int socket_fd = socket(AF_UNIX, SOCK_DGRAM, 0);
+	if(socket_fd < 0) {
+		perror("socket");
+		/* -2 is used to indicate an error */
+		return -2;
+	}
+
+	if(sockin_addr != NULL) {
+		unlink(sockin_addr->sun_path);
+
+		if (bind(socket_fd, (struct sockaddr*)sockin_addr, sizeof(*sockin_addr)) < 0) {
+			perror("bind");
+			close(socket_fd);
+			/* -2 is used to indicate an error */
+			return -2;
+		}
+	}
+
+	return socket_fd;
+}
+
+static void handle_input_socket(struct fxlink_device *fdev, int socket_fd)
+{
+	if(socket_fd < 0) {
+		return;
+	}
+
+	/* Don't start an OUT transfer if there's one in progress */
+	if(fdev->comm->ftransfer_OUT) {
+		return;
+	}
+
+	int dgram_len;
+	if(ioctl(socket_fd, FIONREAD, &dgram_len) < 0) {
+		perror("ioctl");
+		return;
+	}
+	if(dgram_len <= 0) {
+		return;
+	}
+
+	/* We need to use a static buffer as libfxlink will use it in it's main loop,
+	 * outside of this stack frame
+	 */
+	static uint8_t* dgram_buf = NULL;
+	static ssize_t dgram_buf_len = 0;
+	if (dgram_buf_len < dgram_len) {
+		dgram_buf = realloc(dgram_buf, dgram_len);
+		dgram_buf_len = dgram_len;
+	}
+
+	ssize_t recv_ret = recvfrom(socket_fd, dgram_buf, dgram_buf_len, 0, NULL, NULL);
+	if(recv_ret < 0) {
+		perror("recvfrom");
+	} else if(recv_ret > 0) {
+		fxlink_device_start_bulk_OUT(fdev, "fxlink", "text", dgram_buf, recv_ret, false);
+	}
+}
+
 int main_interactive(struct fxlink_filter *filter, delay_t *delay,
-	libusb_context *ctx)
+	libusb_context *ctx,
+	const struct sockaddr_un *sockin_addr,
+	const struct sockaddr_un *sockout_addr)
 {
 	/* Wait for a device to be connected */
 	fxlink_filter_clean_libusb(filter);
@@ -113,6 +193,14 @@ int main_interactive(struct fxlink_filter *filter, delay_t *delay,
 		return 1;
 	}
 
+	/* socket used by sockin and sockout options */
+	int socket_fd = setup_socket(sockin_addr, sockout_addr);
+	if(socket_fd <= -2) {
+		fxlink_device_cleanup(fdev);
+		free(fdev);
+		return 1;
+	}
+
 	hlog("interactive");
 	log_("connected to %s\n", fxlink_device_id(fdev));
 
@@ -124,6 +212,8 @@ int main_interactive(struct fxlink_filter *filter, delay_t *delay,
 	while(1) {
 		fxlink_sdl2_handle_events();
 
+		handle_input_socket(fdev, socket_fd);
+
 		int transferred = -1;
 		int rc = libusb_bulk_transfer(fdev->dh, fdev->comm->ep_bulk_IN, buffer,
 			sizeof buffer, &transferred, 500 /* ms */);
@@ -150,7 +240,7 @@ int main_interactive(struct fxlink_filter *filter, delay_t *delay,
 		if(tr && fxlink_transfer_complete(tr)) {
 			struct fxlink_message *msg = fxlink_transfer_finish_IN(tr);
 			if(msg) {
-				handle_new_message(fdev, msg);
+				handle_new_message(fdev, msg, socket_fd, sockout_addr);
 				fxlink_message_free(msg, true);
 			}
 			tr = NULL;
@@ -163,6 +253,10 @@ int main_interactive(struct fxlink_filter *filter, delay_t *delay,
 		fxlink_transfer_free(tr);
 	}
 
+	if(socket_fd >= 0) {
+		close(socket_fd);
+	}
+
 	fxlink_device_cleanup(fdev);
 	free(fdev);
 	return 0;