Update CHANGELOG.md

Minecraft servers have a longstanding bug that omits newlines
when sending messages via RCON. This patch manually inserts
newlines to address the issue.

Reference: https://bugs.mojang.com/browse/MC-7569

Fixes #1

CHANGELOG.md

@@ -1,17 +1,20 @@
 #### Version history:
 
-###### 0.7.3
+###### 0.8.0
+ - Implement support for multipacket responses
  - Add support to Valve style rcon authentication
  - Change maximum packet size to correct value (4096 -> 4106)
+ - Attempt to add missing newlines in Minecraft servers
+    * Currently implemented only for the 'help' command
  - Print auth failed message to stderr instead of stdout
  - Fail immediately if received packet size is out of spec
  - Return proper exit code from run_terminal_mode()
  - Add error messages to rcon_command() function
- 
+
 ###### 0.7.2
  - Quit gracefully when Ctrl-D or Ctrl+C is pressed
  - Remove "exit" and "quit" as quitting commands
-    * these are actual rcon commands on some servers
+    * These are actual rcon commands on some servers
  - Suppress compiler warning (strncpy)
  - Fix erroneous string length in packet building function
  - Fix typo in ANSI escape sequence for LCYAN

mcrcon.1

@@ -1,7 +1,7 @@
 .\" Process this file with
 .\" groff -man -Tascii mcrcon.1
 .\"
-.TH MCRCON 1 "November 2024" "Version 0.7.3"
+.TH MCRCON 1 "December 2024" "Version 0.8.0"
 .SH NAME 
 mcrcon \- send rcon commands to a Minecraft server
 .SH SYNOPSIS

mcrcon.c

@@ -41,7 +41,7 @@
     #include <netdb.h>
 #endif
 
-#define VERSION "0.7.3"
+#define VERSION "0.8.0"
 #define IN_NAME "mcrcon"
 #define VER_STR IN_NAME" "VERSION" (built: "__DATE__" "__TIME__")"
 
@@ -95,16 +95,17 @@ void        packet_print(rc_packet *packet);
 bool        rcon_auth(int sock, char *passwd);
 int         rcon_command(int sock, char *command);
 
-
 // =============================================
 //  GLOBAL VARIABLES
 // =============================================
-static int flag_raw_output = 0;
-static int flag_silent_mode = 0;
-static int flag_disable_colors = 0;
-static int flag_wait_seconds = 0;
-static int global_connection_alive = 1;
-static int global_rsock;
+static int  flag_raw_output = 0;
+static int  flag_silent_mode = 0;
+static int  flag_disable_colors = 0;
+static int  flag_wait_seconds = 0;
+static int  global_connection_alive = 1;
+static bool global_valve_protocol = false;
+static bool global_minecraft_newline_fix = false;
+static int  global_rsock;
 
 #ifdef _WIN32
   // console coloring on windows
@@ -166,10 +167,6 @@ int main(int argc, char *argv[])
 	if (!port) port = "25575";
 	if (!host) host = "localhost";
 
-	// disable output buffering (https://github.com/Tiiffi/mcrcon/pull/39)
-	setvbuf(stdout, NULL, _IONBF, 0);
-	setvbuf(stderr, NULL, _IONBF, 0);
-
 	if(argc < 1 && pass == NULL) usage();
 
 	// default getopt error handler enabled
@@ -483,9 +480,7 @@ void packet_print(rc_packet *packet)
 	uint8_t *data = packet->data;
 
 	if (flag_raw_output == 1) {
-		for (int i = 0; data[i] != 0; ++i) {
-			putchar(data[i]);
-		}
+		fputs((char *) data, stdout);
 		return;
 	}
 
@@ -499,34 +494,38 @@ void packet_print(rc_packet *packet)
 		} else default_color = 0x37;
 	#endif
 
-	// colors enabled so try to handle the bukkit colors for terminal
-	if (flag_disable_colors == 0) {
-		for (i = 0; data[i] != 0; ++i) {
-			if (data[i] == 0x0A) print_color(default_color);
-			else if(data[i] == 0xc2 && data[i + 1] == 0xa7) {
-				i += 2;
+	bool slash = false;
+	bool colors_detected = false;
+
+	for (i = 0; data[i] != 0; ++i)
+	{
+		if (data[i] == 0x0A) {
+			print_color(default_color);
+		}
+		else if(data[i] == 0xc2 && data[i + 1] == 0xa7) {
+			// Disable new line fixes if Bukkit colors are detected
+			colors_detected = true;
+			i += 2;
+			if (flag_disable_colors == 0) {
 				print_color(data[i]);
-				continue;
 			}
-			putchar(data[i]);
+			continue;
 		}
-		print_color(default_color); // cancel coloring
-	}
-	// strip colors
-	else {
-		for (i = 0; data[i] != 0; ++i) {
-			if (data[i] == 0xc2 && data[i + 1] == 0xa7) {
-				i += 2;
-				continue;
-			}	
-			putchar(data[i]);
+
+		if (colors_detected == false && global_minecraft_newline_fix && data[i] == '/') {
+			slash ? putchar('\n') : (slash = true);
 		}
+
+		putchar(data[i]);
 	}
+	print_color(default_color); // cancel coloring
 
 	// print newline if string has no newline
-	if (data[i - 1] != 10 && data[i - 1] != 13) {
+	if (data[i - 1] != '\n') {
 		putchar('\n');
 	}
+
+	fflush(stdout);
 }
 
 rc_packet *packet_build(int id, int cmd, char s[static 1])
@@ -573,6 +572,7 @@ receive:
 	 * so we have to check packet type and try again if necessary.
 	 */
 	if (packet->cmd != RCON_AUTH_RESPONSE) {
+		global_valve_protocol = true;
 		goto receive;
 	}
 
@@ -580,9 +580,11 @@ receive:
 	return packet->id == -1 ? false : true;
 }
 
-// TODO: Add proper error handling and reporting!
 int rcon_command(int sock, char *command)
 {
+	if (global_valve_protocol == false && strcasecmp(command, "help") == 0)
+		global_minecraft_newline_fix = true;
+
 	rc_packet *packet = packet_build(RCON_PID, RCON_EXEC_COMMAND, command);
 	if (packet == NULL) {
 		log_error("Error: packet build() failed!\n");
@@ -594,21 +596,60 @@ int rcon_command(int sock, char *command)
 		return 0;
 	}
 
-	packet = net_recv_packet(sock);
+	// Workaround to handle valve multipacket responses
+	// This one does not require using select()
+	packet = packet_build(0xBADA55, 0xBADA55, "");
 	if (packet == NULL) {
-		log_error("Error: net_recv_packet() failed!\n");
+		log_error("Error: packet build() failed!\n");
 		return 0;
 	}
 
-	if (packet->id != RCON_PID) {
-		log_error("Error: invalid packet id!\n");
+	if (!net_send_packet(sock, packet)) {
+		log_error("Error: net_send_packet() failed!\n");
 		return 0;
 	}
 
-	if (!flag_silent_mode) {
-		if (packet->size > 10)
-		packet_print(packet);
+	// initialize stuff for select()
+	fd_set read_fds;
+	FD_ZERO(&read_fds);
+	FD_SET(sock, &read_fds);
+
+	// Set 5 second timeout
+	struct timeval timeout = {0};
+	timeout.tv_sec = 5;
+	timeout.tv_usec = 0;
+
+	int incoming = 0;
+
+	do {
+		packet = net_recv_packet(sock);
+		if (packet == NULL) {
+			log_error("Error: net_recv_packet() failed!\n");
+			return 0;
+		}
+
+		// Check for packet id and multipacket guard id
+		if (packet->id != RCON_PID && packet->id != 0xBADA55) {
+			log_error("Error: invalid packet id!\n");
+			return 0;
+		}
+
+		if (packet->id == 0xBADA55) break;
+
+		if (flag_silent_mode == false) {
+			if (packet->size > 10)
+			packet_print(packet);
+		}
+
+		int result = select(sock + 1, &read_fds, NULL, NULL, &timeout);
+		if (result == -1) {
+			log_error("Error: select() failed!\n");
+			return 0;
+		}
+
+		incoming = (result > 0 && FD_ISSET(sock, &read_fds));
 	}
+	while(incoming);
 
 	return 1;
 }
@@ -645,6 +686,7 @@ int run_terminal_mode(int sock)
 
 	while (global_connection_alive) {
 		putchar('>');
+		fflush(stdout);
 
 		int len = get_line(command, MAX_COMMAND_LENGTH);
 		if (len < 1) continue;