gdb: provide [fxsdk gdb] wrapper

fxsdk/fxsdk.sh

@@ -51,6 +51,11 @@ ${R}fxsdk${n} (${R}send${n}|${R}send-fx${n}|${R}send-cg${n})
   externally) for the fx-9860G, and fxlink for the fx-CG. For the G-III series,
   call fxlink directly instead of this command.
 
+${R}fxsdk${n} ${R}gdb${n} [${g}<OPTIONS>${n}...] [${R}--${n} ${g}<GDB OPTIONS>${n}...]
+  Starts the GDB bridge and GDB itself. In general, you'll want at least one
+  GDB option--the path to the executable file to debug.
+  With --bridge-only, don't start GDB and instead enable bridge logs.
+
 ${R}fxsdk${n} ${R}path${n} (${R}sysroot${n}|${R}include${n}|${R}lib${n})
   Prints commonly-used paths in the SuperH sysroot:
     ${R}sysroot${n}    The root folder of the SuperH toolchain and libraries
@@ -335,6 +340,8 @@ case "$1" in
     fxsdk_send_cg;;
 
   # Utilities
+  "gdb")
+    fxsdk-gdb-bridge "${@:2}";;
   "path")
     fxsdk_path "${@:2}";;
 

fxsdk/gdb-bridge.c

@@ -4,7 +4,10 @@
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <sys/wait.h>
 #include <unistd.h>
+#include <getopt.h>
+#include <signal.h>
 
 #include <libusb.h>
 
@@ -50,8 +53,8 @@ static struct fxlink_device *setup_calc(libusb_context *context, bool nostart)
 		struct fxlink_message *msg = fxlink_device_finish_bulk_IN(fdev);
 		if(!msg)
 			continue;
+		hlog("gdb");
 		if(fxlink_message_is_apptype(msg, "gdb", "start")) {
-			hlog("gdb");
 			log_("got start message\n");
 			break;
 		}
@@ -72,6 +75,8 @@ static int setup_socket(char const *listen_path)
 		return -1;
 	}
 
+	unlink(listen_path);
+
 	struct sockaddr_un listen_address = {
 		.sun_family = AF_UNIX,
 		.sun_path = {0},
@@ -92,6 +97,58 @@ static int setup_socket(char const *listen_path)
 
 	hlog("socket");
 	log_("waiting for client on \"%s\"...\n", listen_address.sun_path);
+
+	return listen_socket;
+}
+
+static int volatile gdb_terminated_flag = 0;
+static int volatile interrupted_flag = 0;
+
+void SIGINT_SIGCHLD_handler(int signal)
+{
+	if(signal == SIGCHLD)
+		gdb_terminated_flag = 1;
+	else
+		interrupted_flag = 1;
+}
+
+static pid_t fork_gdb(char **user_argv, char const *socket_path)
+{
+	int n = 0;
+	while(user_argv[n])
+		n++;
+
+	char target_command[256];
+	sprintf(target_command, "target remote %s", socket_path);
+
+	char **argv = malloc((n + 5) * sizeof *argv);
+	argv[0] = "sh-elf-gdb";
+	argv[1] = "-q";
+	argv[2] = "-ex";
+	argv[3] = target_command;
+	memcpy(argv+4, user_argv, (n+1) * sizeof *argv);
+
+	struct sigaction action = {
+		.sa_handler = SIGINT_SIGCHLD_handler,
+	};
+	sigaction(SIGCHLD, &action, NULL);
+
+	pid_t pid = fork();
+
+	/* Child - execvp() only returns if there is an error */
+	if(pid == 0) {
+		execvp("sh-elf-gdb", argv);
+		perror("execvp");
+		exit(1);
+	}
+	/* Parent */
+	if(pid == -1)
+		perror("fork");
+	return pid;
+}
+
+static int accept_gdb(int listen_socket)
+{
 	int client_socket = accept(listen_socket, NULL, NULL);
 	if(client_socket < 0) {
 		close(listen_socket);
@@ -102,17 +159,42 @@ static int setup_socket(char const *listen_path)
 	return client_socket;
 }
 
-int main(int argc, char *argv[])
+struct options {
+	bool bridge_only;
+};
+
+/* Parse options, returns positional arguments to forward to gdb. */
+static char **parse_argv(int argc, char **argv, struct options *opts)
+{
+	int bridge_only = 0;
+	struct option longs[] = {
+		{ "bridge-only", no_argument, &bridge_only, 1 },
+		{ NULL },
+	};
+
+	getopt_long(argc, argv, "", longs, NULL);
+
+	opts->bridge_only = (bridge_only != 0);
+	return argv + optind + (argv[optind] && !strcmp(argv[optind], "--"));
+}
+
+static void noop_log_handler(int display_fmt, char const *str)
+{
+	(void)display_fmt;
+	(void)str;
+}
+
+int main(int argc, char **argv)
 {
 	libusb_context *context = NULL;
 	struct fxlink_device *fdev = NULL;
 	struct fxlink_pollfds fxlink_polled_fds = { 0 };
+	char socket_path[256] = { 0 };
+	pid_t gdb_pid = -1;
 	int ret = 1;
 
-	if(argc != 2) {
+	struct options opts;
-		elog("Usage : %s [listen path]\n", argv[0]);
+	char **gdb_argv = parse_argv(argc, argv, &opts);
-		goto end;
-	}
 
 	int err = libusb_init(&context);
 	if(err != 0) {
@@ -124,17 +206,37 @@ int main(int argc, char *argv[])
 	if(!fdev)
 		goto end;
 
-	int client_socket = setup_socket(argv[1]);
+	sprintf(socket_path, "/tmp/fxsdk-gdb-bridge-%03d-%03d.socket",
+		fdev->busNumber, fdev->deviceAddress);
+
+	int listen_socket = setup_socket(socket_path);
+	if(listen_socket < 0)
+		goto end;
+
+	if(!opts.bridge_only) {
+		gdb_pid = fork_gdb(gdb_argv, socket_path);
+		if(gdb_pid == -1)
+			goto end;
+		/* Cut fxlink logs to not mix in with gdb's output */
+		fxlink_log_set_handler(noop_log_handler);
+	}
+
+	int client_socket = accept_gdb(listen_socket);
 	if(client_socket < 0)
 		goto end;
 
+	struct sigaction action = {
+		.sa_handler = SIGINT_SIGCHLD_handler,
+	};
+	sigaction(SIGINT, &action, NULL);
+
 	/* Track libusb fds as an indirect way to watch the calculator itself */
 	struct pollfd client_socket_pollfd = {
 		.fd = client_socket, .events = POLLIN
 	};
 	fxlink_pollfds_track(&fxlink_polled_fds, context);
 
-	while(true) {
+	while(!interrupted_flag && !gdb_terminated_flag) {
 		int err = fxlink_multipoll(-1,
 			fxlink_polled_fds.fds, fxlink_polled_fds.count,
 			&client_socket_pollfd, 1,
@@ -150,12 +252,14 @@ int main(int argc, char *argv[])
 		struct fxlink_message *msg;
 		while((msg = fxlink_device_finish_bulk_IN(fdev)) != NULL) {
 			if(!fxlink_message_is_apptype(msg, "gdb", "remote")) {
+				hlog("gdb");
 				wlog("dropped a message of type %.16s:%.16s\n",
 					msg->application, msg->type);
 				fxlink_device_start_bulk_IN(fdev);
 				continue;
 			}
-			printf("CAL> %.*s\n", msg->size, (char *)msg->data);
+			if(opts.bridge_only)
+				printf("CAL> %.*s\n", msg->size, (char *)msg->data);
 			ssize_t send_ret = send(client_socket, msg->data, msg->size, 0);
 			if(send_ret != msg->size) {
 				perror("send");
@@ -182,7 +286,8 @@ int main(int argc, char *argv[])
 				perror("recv");
 				goto end;
 			}
-			printf("GDB> %.*s\n", (int)recv_ret, buf);
+			if(opts.bridge_only)
+				printf("GDB> %.*s\n", (int)recv_ret, buf);
 			if(!fxlink_device_start_bulk_OUT(fdev, "gdb", "remote", buf, recv_ret, false)) {
 				elog("unable to start bulk OUT transfer\n");
 				goto end;
@@ -193,8 +298,10 @@ int main(int argc, char *argv[])
 	ret = 0;
 
 end:
-	/* TODO: Close socket at end, including after ^C */
+	if(gdb_pid != -1)
-
+		waitpid(gdb_pid, NULL, 0);
+	if(socket_path[0])
+		unlink(socket_path);
 	if(fxlink_polled_fds.ctx)
 		fxlink_pollfds_stop(&fxlink_polled_fds);
 	if(fdev) {