fix buffer overflow in error handling module

- fixed ring buffer overflow in errcatch module
- fixed naming of commands in sercomm module
- added comments to macro's in consts.h
- properly handle `W2_E_WARN_UNCAUGHT_ERROR` and
  `W2_E_WARN_ERR_BUFFER_FULL` (these used to cause infinite loops)
- added buffer full warning code
- added options to hide some simulation messages
- more boilerplate sercomm module code

7 files changed, 68 insertions, 37 deletions

diff --git a/robot/consts.h b/robot/consts.h
index d74d034..94a161d 100644
--- a/robot/consts.h
+++ b/robot/consts.h
@@ -5,6 +5,11 @@
 #define W2_BUILD_STR ("????????")
 #endif
 
+/** max logic module execution time in milliseconds */
 #define W2_MAX_MODULE_CYCLE_MS (20)
+/** serial baud rate (bit/s) */
 #define W2_SERIAL_BAUD (9600)
-#define W2_E_BUFFER_SIZE (16)
+/** size of the error handling buffer (in errors, not bytes) */
+#define W2_ERROR_BUFFER_SIZE (16)
+/** size of the serial communication buffer (in messages, not bytes) */
+#define W2_SERCOMM_BUFFER_SIZE (16)
diff --git a/robot/errcatch.c b/robot/errcatch.c
index 1262a38..f66b2a1 100644
--- a/robot/errcatch.c
+++ b/robot/errcatch.c
@@ -8,15 +8,25 @@
 #include "modes.h"
 #include "orangutan_shim.h"
 
-w2_s_error *g_w2_error_buffer[W2_E_BUFFER_SIZE] = {};
-uint8_t g_w2_error_index						= 0;
-uint8_t g_w2_error_offset						= 0;
+w2_s_error *g_w2_error_buffer[W2_ERROR_BUFFER_SIZE] = {};
+uint8_t g_w2_error_index							= 0;
+uint8_t g_w2_error_offset							= 0;
+uint8_t g_w2_error_buffer_full						= 0;
+uint8_t g_w2_error_uncaught							= 0;
 
 void w2_errcatch_main() {
 	while (g_w2_error_index != g_w2_error_offset) {
 		w2_s_error *error = g_w2_error_buffer[g_w2_error_offset];
 		w2_errcatch_handle_error(error);
-		g_w2_error_offset = (g_w2_error_offset + 1) % W2_E_BUFFER_SIZE;
+		g_w2_error_offset = (g_w2_error_offset + 1) % W2_ERROR_BUFFER_SIZE;
+	}
+	if (g_w2_error_buffer_full) {
+		w2_errcatch_throw(W2_E_WARN_ERR_BUFFER_FULL);
+		g_w2_error_buffer_full = 0;
+	}
+	if (g_w2_error_uncaught) {
+		w2_errcatch_throw(W2_E_WARN_UNCAUGHT_ERROR);
+		g_w2_error_uncaught = 0;
 	}
 }
 
@@ -30,10 +40,13 @@ w2_s_error *w2_alloc_error(enum w2_e_errorcodes code, uint16_t length, const cha
 
 void w2_errcatch_throw(enum w2_e_errorcodes code) { w2_errcatch_throw_msg(code, 0, ""); }
 void w2_errcatch_throw_msg(enum w2_e_errorcodes code, uint16_t length, const char *message) {
+	uint8_t next_index	   = (g_w2_error_index + 1) % W2_ERROR_BUFFER_SIZE;
+	g_w2_error_buffer_full = next_index == g_w2_error_offset;
 	free(g_w2_error_buffer[g_w2_error_index]);
 	w2_s_error *error					= w2_alloc_error(code, length, message);
 	g_w2_error_buffer[g_w2_error_index] = error;
-	g_w2_error_index					= (g_w2_error_index + 1) % W2_E_BUFFER_SIZE;
+	if (g_w2_error_buffer_full) return;
+	g_w2_error_index = next_index;
 }
 
 void w2_errcatch_handle_error(w2_s_error *error) {
@@ -48,7 +61,7 @@ void w2_errcatch_handle_error(w2_s_error *error) {
 			break;
 		}
 		default: {
-			w2_errcatch_throw(W2_E_WARN_UNCAUGHT_ERROR);
+			g_w2_error_uncaught = 1;
 #ifdef W2_SIM
 			simwarn("Uncaught/unhandled error found with code 0x%02x\n", error->code);
 #endif
diff --git a/robot/errcatch.h b/robot/errcatch.h
index ec4b90f..9f737d8 100644
--- a/robot/errcatch.h
+++ b/robot/errcatch.h
@@ -29,6 +29,7 @@ enum w2_e_errorcodes {
 	W2_E_WARN_OBSTACLE_DETECTED = 0x01 | W2_E_TYPE_WARN,
 	W2_E_WARN_CYCLE_EXPIRED		= 0x02 | W2_E_TYPE_WARN,
 	W2_E_WARN_UNCAUGHT_ERROR	= 0x03 | W2_E_TYPE_WARN,
+	W2_E_WARN_ERR_BUFFER_FULL	= 0x04 | W2_E_TYPE_WARN,
 };
 
 /**
@@ -44,7 +45,7 @@ typedef struct {
 } w2_s_error;
 
 /** error ring buffer */
-extern w2_s_error *g_w2_error_buffer[W2_E_BUFFER_SIZE];
+extern w2_s_error *g_w2_error_buffer[W2_ERROR_BUFFER_SIZE];
 /** stores head of ring buffer */
 extern uint8_t g_w2_error_index;
 /** stores start of ring buffer */
diff --git a/robot/hypervisor.c b/robot/hypervisor.c
index dbdc62a..c558de8 100644
--- a/robot/hypervisor.c
+++ b/robot/hypervisor.c
@@ -1,5 +1,4 @@
 #include "hypervisor.h"
-#include "consts.h"
 #include "errcatch.h"
 #include "io.h"
 #include "modes.h"
@@ -7,6 +6,10 @@
 #include "sercomm.h"
 
 void w2_hypervisor_main() {
+#ifdef W2_SIM
+	siminfo("cycle start\n");
+#endif
+
 	time_reset();
 
 	w2_sercomm_main();
@@ -18,14 +21,10 @@ void w2_hypervisor_main() {
 	w2_modes_main();
 	unsigned long mode_time = get_ms() - io_time;
 
-#ifdef W2_SIM
-	siminfo("sercomm:  %lums\n", sercomm_time);
-	siminfo("errcatch: %lums\n", errcatch_time);
-	siminfo("io:       %lums\n", io_time);
-	siminfo("mode:     %lums\n", mode_time);
+	if (mode_time > W2_MAX_MODULE_CYCLE_MS) w2_errcatch_throw(W2_E_WARN_CYCLE_EXPIRED);
 
+#ifdef W2_SIM
+	siminfo("cycle end\n");
 	usleep(100e3);
 #endif
-
-	if (mode_time > W2_MAX_MODULE_CYCLE_MS) w2_errcatch_throw(W2_E_WARN_CYCLE_EXPIRED);
 }
diff --git a/robot/makefile b/robot/makefile
index 6f50519..ce57090 100644
--- a/robot/makefile
+++ b/robot/makefile
@@ -34,7 +34,7 @@ CFLAGS += -DW2_BUILD_STR="$(BUILD_STR)"
 all: $(if $(SIM), a.out, out.hex)
 
 clean:
-	rm -f *.o out.hex a.out compile_commands.json
+	rm -f *.o out.hex a.out
 
 a.out: $(OBJECTS)
 	$(CC) $(OBJECTS) $(CFLAGS) $(LDFLAGS)
diff --git a/robot/sercomm.h b/robot/sercomm.h
index 1533a4c..d960d0d 100644
--- a/robot/sercomm.h
+++ b/robot/sercomm.h
@@ -1,27 +1,35 @@
 #pragma once
 
 #include "bin.h"
+#include "consts.h"
 
-#define W2_CMD_RX (0)
-#define W2_CMD_TX (1)
+#define W2_CMDDIR_RX (0)
+#define W2_CMDDIR_TX (1)
 
 enum w2_e_serial_commands {
-	W2_E_CMD_PING = 0x00,
-	W2_E_CMD_EXPT = 0x02,
-	W2_E_CMD_MODE = 0x04,
-	W2_E_CMD_SPED = 0x06,
-	W2_E_CMD_DIRC = 0x08,
-	W2_E_CMD_CORD = 0x0a,
-	W2_E_CMD_BOMD = 0x0c,
-	W2_E_CMD_SRES = 0x0e,
-	W2_E_CMD_MCFG = 0x10,
-	W2_E_CMD_SENS = 0x12,
-	W2_E_CMD_INFO = 0x14,
-	W2_E_CMD_DISP = 0x16,
-	W2_E_CMD_PLAY = 0x18,
-	W2_E_CMD_CLED = 0x1a,
+	W2_CMD_PING = 0x00,
+	W2_CMD_EXPT = 0x02,
+	W2_CMD_MODE = 0x04,
+	W2_CMD_SPED = 0x06,
+	W2_CMD_DIRC = 0x08,
+	W2_CMD_CORD = 0x0a,
+	W2_CMD_BOMD = 0x0c,
+	W2_CMD_SRES = 0x0e,
+	W2_CMD_MCFG = 0x10,
+	W2_CMD_SENS = 0x12,
+	W2_CMD_INFO = 0x14,
+	W2_CMD_DISP = 0x16,
+	W2_CMD_PLAY = 0x18,
+	W2_CMD_CLED = 0x1a,
 };
 
+/** sercomm ring buffer */
+extern w2_s_bin *g_w2_sercomm_buffer[W2_SERCOMM_BUFFER_SIZE];
+/** stores head of ring buffer */
+extern uint8_t g_w2_error_index;
+/** stores start of ring buffer */
+extern uint8_t g_w2_error_offset;
+
 /**
  * serial pc-robot communication module
  *
diff --git a/robot/sim.h b/robot/sim.h
index 15a1b4b..9c80ecf 100644
--- a/robot/sim.h
+++ b/robot/sim.h
@@ -4,6 +4,11 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+// debug fine-tuning
+#define DBG_ENABLE_PRINTFUNC (0)
+#define DBG_ENABLE_SIMWARN (1)
+#define DBG_ENABLE_SIMINFO (1)
+
 // debug print options
 #define DBG_BYTES_PER_LINE 16
 
@@ -21,10 +26,10 @@
 // debug stdout print macros
 #define simprintf(message, ...) printf(COL_RED "[SIM] " COL_RST message, ##__VA_ARGS__)
 #define simprint(message) simprintf(message "\n")
-#define simprintfunc(name, fmt, ...) simprintf(COL_BLU "[FUNC] " \
-		COL_CYN name COL_RST "(" COL_YEL fmt COL_RST ")\n", ##__VA_ARGS__)
-#define simwarn(message, ...) simprintf(COL_YEL "[WARN] " COL_RST message, ##__VA_ARGS__)
-#define siminfo(message, ...) simprintf(COL_MAG "[INFO] " COL_RST message, ##__VA_ARGS__)
+#define simprintfunc(name, fmt, ...) if (DBG_ENABLE_PRINTFUNC) { simprintf(COL_BLU "[FUNC] " \
+		COL_CYN name COL_RST "(" COL_YEL fmt COL_RST ")\n", ##__VA_ARGS__); }
+#define simwarn(message, ...) if (DBG_ENABLE_SIMWARN) { simprintf(COL_YEL "[WARN] " COL_RST message, ##__VA_ARGS__); }
+#define siminfo(message, ...) if (DBG_ENABLE_SIMINFO) { simprintf(COL_MAG "[INFO] " COL_RST message, ##__VA_ARGS__); }
 
 /**
  * simulates pololu library functions for local testing