From 629fa5fc565a7c8a67fa7c3eb46babdff10cf19e Mon Sep 17 00:00:00 2001
From: vhaudiquet <vhaudiquet343@hotmail.fr>
Date: Sun, 8 Oct 2023 15:15:34 +0200
Subject: [PATCH] gdbstub: ctrl-c command support

---
 src/gdbstub/gdbstub.c | 56 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 54 insertions(+), 2 deletions(-)

diff --git a/src/gdbstub/gdbstub.c b/src/gdbstub/gdbstub.c
index 5da7480..f98d6bc 100644
--- a/src/gdbstub/gdbstub.c
+++ b/src/gdbstub/gdbstub.c
@@ -24,6 +24,7 @@ socket_t gdbstub_server_socket;
 socket_t gdb_socket;
 
 void gdbstub_thread_gdb();
+static void gdbstub_handle_ctrlc();
 
 /*
  * Receive a packet from client gdb
@@ -35,9 +36,27 @@ static void gdbstub_recv_packet(char* packet, ssize_t* size)
 	recv(gdb_socket, &data, 1, 0);
 
 	// Start of packet symbol is '$'
-	// Skip data that is not packet (should only be ACK '+')
+	// Skip data that is not packet
 	if(data != '$')
-		return gdbstub_recv_packet(packet, size);
+	{
+		switch(data)
+		{
+			case '+':
+				// '+' : ACK
+				// We ignore ACK, so read next
+				return gdbstub_recv_packet(packet, size);
+				break;
+			case 0x3:
+				// 0x3 : COMMAND CTRL-C (interrupt execution)
+				gdbstub_handle_ctrlc();
+				return gdbstub_recv_packet(packet, size);
+				break;
+			default:
+				// Ignore unknown data
+				return gdbstub_recv_packet(packet, size);
+				break;
+		}
+	}
 
 	// Receive packet until end of packet '#' symbol
 	size_t i = 0;
@@ -153,6 +172,7 @@ void gdbstub_thread_gdb()
 		// Analyse packet to respond correctly
 		if(packet[0] == '?')
 		{
+			// Halt Reason : Signal 05 (SIGTRAP)
 			char* resp = "S05";
 			gdbstub_send_packet(resp, 3);
 		}
@@ -198,6 +218,38 @@ void gdbstub_thread_gdb()
 
 			gdbstub_send_packet("OK", 2);
 		}
+		else if(packet[0] == 's')
+		{
+			// s : single-step
+
+			// Send back halt reason
+			// Halt Reason : Signal 05 (SIGTRAP)
+			char* resp = "S05";
+			gdbstub_send_packet(resp, 3);
+		}
+		else if(packet[0] == 'c')
+		{
+			// c : continue until something happens
+
+			// Send an ACK
+			send(gdb_socket, "+", 1, 0);
+
+			// Continue simulation
+		}
 		else gdbstub_send_unsupported();
 	}
 }
+
+/*
+ * Handles the GDB CTRL+C (^C) command, that
+ * should interrupt the simulation
+ */
+static void gdbstub_handle_ctrlc()
+{
+	// Halt the simulation
+
+	// Send back halt signal to gdb
+	// Halt Reason : Signal 05 (SIGTRAP)
+	char* resp = "S05";
+	gdbstub_send_packet(resp, 3);
+}