Enable input/output buffering and fflush only explicitly

As suggested in old pull request: #39

.travis.yml

@@ -1,20 +0,0 @@
-language: c
-sudo: false
-dist: trusty
-cache:
-  ccache: true
-compiler:
-- gcc
-- clang
-env:
-  global:
-  - EXTRAFLAGS='-v'
-  - PREFIX="${HOME}"
-install:
-- 'true'
-script:
-- make
-- ./mcrcon -h
-- ./mcrcon -v
-- make install
-- make uninstall

BUILDING.md

@@ -0,0 +1,29 @@
+Building and installing
+-----------------------
+
+#### Requirements & dependencies:
+- GCC compatible compiler
+- POSIX getopt support from **<unistd.h>**
+
+---
+
+#### Compiling
+
+    cc -std=gnu99 -Wpedantic -Wall -Wextra -Wno-gnu-zero-variadic-macro-arguments -O2 -o mcrcon mcrcon.c
+    
+>[!NOTE]
+>If you are compiling on Windows remember to link with winsock by adding `-lws2_32` to your compiler command line.
+
+---
+
+Or you can run **make**
+
+    make           - compiles mcrcon
+    make install   - installs compiled binaries and manpage to the system
+    make uninstall - removes binaries and manpage from the system
+    
+    file install locations:
+        /usr/local/bin/mcrcon
+        /usr/local/share/man/man1/mcrcon.1
+
+Makefile **install** and **uninstall** rules are not available on Windows.

CHANGELOG.md

@@ -1,5 +1,22 @@
 #### Version history:
 
+###### 0.7.3
+ - Add support to Valve style rcon authentication
+ - Change maximum packet size to correct value (4096 -> 4106)
+ - 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
+ - Suppress compiler warning (strncpy)
+ - Fix erroneous string length in packet building function
+ - Fix typo in ANSI escape sequence for LCYAN
+ - Make stdout and stderr unbuffered
+
 ###### 0.7.1
  - Deprecate `-i` flag for invoking terminal mode
  - Add workaround to prevent server-side bug.

INSTALL.md

@@ -1,22 +0,0 @@
-Building and installing
-------------------------
-
-Only dependency is C library and POSIX getopt support. 
-
-Compiling with GCC or CLANG:
-
-    cc -std=gnu99 -Wpedantic -Wall -Wextra -Os -s -o mcrcon mcrcon.c
-    
-Note: on Windows remember to link with winsock by adding `-lws2_32` to your compiler command line.
-
-Or you can just run "**make**":
-
-    make           - compiles mcrcon
-    make install   - installs compiled binaries and manpage to the system
-    make uninstall - removes binaries and manpage from the system
-    
-    file install locations:
-        /usr/local/bin/mcrcon
-        /usr/local/share/man/man1/mcrcon.1
-
-Makefile "**install**" and "**uninstall**" rules are disabled on windows.

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2012-2020, Tiiffi <tiiffi at gmail>
+Copyright (c) 2012-2024, Tiiffi <tiiffi at gmail>
 
 This software is provided 'as-is', without any express or implied
 warranty. In no event will the authors be held liable for any damages
@@ -18,4 +18,3 @@ freely, subject to the following restrictions:
 
   3. This notice may not be removed or altered from any source
   distribution.
-  

Makefile

@@ -4,7 +4,7 @@
 #   make
 #
 # Windows cross compile:
-#   i686-w64-mingw32-gcc -std=gnu99 -Wall -Wextra -Wpedantic -Os -s -o mcrcon.exe mcrcon.c -lws2_32
+#   x86_64-w64-mingw32-gcc -std=gnu99 -Wall -Wextra -Wpedantic -O2 -fstack-protector-all -o mcrcon.exe mcrcon.c -lws2_32
 
 EXENAME = mcrcon
 PREFIX ?= /usr/local
@@ -13,9 +13,9 @@ INSTALL = install
 LINKER =
 RM = rm -v -f
 
-CC = gcc
+CC ?= gcc
-CFLAGS = -std=gnu99 -Wall -Wextra -Wpedantic -Os -s
+CFLAGS = -std=gnu99 -Wall -Wextra -Wpedantic -Wno-gnu-zero-variadic-macro-arguments -O2
-EXTRAFLAGS ?= -fstack-protector-strong
+EXTRAFLAGS ?= -fstack-protector-all
 
 ifeq ($(OS), Windows_NT)
 	LINKER = -lws2_32
@@ -23,11 +23,6 @@ ifeq ($(OS), Windows_NT)
 	RM = cmd /C del /F
 endif
 
-ifeq ($(shell uname), Darwin)
-	INSTALL = ginstall
-	CFLAGS = -std=gnu99 -Wall -Wextra -Wpedantic -Os
-endif
-
 .PHONY: all
 all: $(EXENAME)
 
@@ -37,8 +32,8 @@ $(EXENAME): mcrcon.c
 ifneq ($(OS), Windows_NT)
 .PHONY: install
 install:
-	$(INSTALL) -vD $(EXENAME) $(DESTDIR)$(PREFIX)/bin/$(EXENAME)
+	$(INSTALL) -v $(EXENAME) $(DESTDIR)$(PREFIX)/bin/$(EXENAME)
-	$(INSTALL) -vD -m 0644 mcrcon.1 $(DESTDIR)$(PREFIX)/share/man/man1/mcrcon.1
+	$(INSTALL) -v -m 0644 mcrcon.1 $(DESTDIR)$(PREFIX)/share/man/man1/mcrcon.1
 	@echo "\nmcrcon installed. Run 'make uninstall' if you want to uninstall.\n"
 
 .PHONY: uninstall
@@ -49,4 +44,4 @@ endif
 
 .PHONY: clean
 clean:
-	$(RM) $(EXENAME)
+	$(RM) $(EXENAME) $(EXENAME).exe

README.md

@@ -1,33 +1,42 @@
 # mcrcon
 
-mcrcon is console based Minecraft [rcon](https://developer.valvesoftware.com/wiki/Source_RCON_Protocol) client for remote administration and server maintenance scripts.
+mcrcon is a command-line [rcon](https://developer.valvesoftware.com/wiki/Source_RCON_Protocol) client intended for remote server administration and maintenance automation.
+
+Though originally developed for Minecraft servers, it also works with a variety of other servers using the Valve or Minecraft-style rcon protocol.
+
 
 ---
 
-### Installing:
+### Installing
 
-##### via packet manager:
+##### Binary releases
-See https://pkgs.org/download/mcrcon for available packages in various Linux distros (note that available packages might be outdated).
 
-- Gentoo Linux: https://packages.gentoo.org/packages/games-util/mcrcon
+Pre-built binaries are provided for Linux and Windows: https://github.com/Tiiffi/mcrcon/releases/latest
-- Arch Linux: https://aur.archlinux.org/packages/mcrcon/
 
-##### building from sources:
+##### Via package manager
+See https://pkgs.org/download/mcrcon and https://repology.org/project/mcrcon/packages for available packages in various Linux distros (note that some packages might be outdated).
+
+- Fedora: https://packages.fedoraproject.org/pkgs/mcrcon/mcrcon/
+- Gentoo: https://packages.gentoo.org/packages/games-util/mcrcon
+- Arch: https://aur.archlinux.org/packages/mcrcon/
+- NixOS: https://search.nixos.org/packages?show=mcrcon
+- Snapcraft: https://snapcraft.io/mcrcon-nsg
+- Scoop: https://scoop.sh/#/apps?q=mcrcon
+
+##### Building from sources
 ```sh
 git clone https://github.com/Tiiffi/mcrcon.git
 cd mcrcon
 make
+
+# install is optional
 sudo make install
 ```
-Check [INSTALL.md](INSTALL.md) for more details.
+_Check [BUILDING.md](BUILDING.md) for more details._
-
-Precompiled binaries (if provided)*: https://github.com/Tiiffi/mcrcon/releases/latest
-
-<sub>*At the moment binaries are provided for Linux and Windows.</sub>
 
 ---
 
-### Usage:
+### Usage
 mcrcon [OPTIONS] [COMMANDS]
 
 Sends rcon commands to Minecraft server.
@@ -56,37 +65,44 @@ MCRCON_PASS
 - Command-line options will override environment variables
 - Rcon commands with spaces must be enclosed in quotes
 
-Example:
+###### Example:
-> Send three commands ("say", "save-all", "stop") and wait five seconds between the commands.
+Send three commands ("say", "save-all", "stop") and wait five seconds between the commands:
 
-  ```mcrcon -H my.minecraft.server -p password -w 5 "say Server is restarting!" save-all stop```
+```sh
+mcrcon -H my.minecraft.server -p password -w 5 "say Server is restarting!" save-all stop
+```
+---
+
+> [!TIP]
+>Enable RCON on Minecraft server by adding following lines to [```server.properties```](https://minecraft.gamepedia.com/Server.properties) configuration file.
+>```
+>enable-rcon=true
+>rcon.port=25575
+>rcon.password=your_rcon_pasword
+>```
 
 ---
 
-##### Enable rcon on server
+### Contact
-Remember to enable rcon by adding following lines to [```server.properties```](https://minecraft.gamepedia.com/Server.properties) file.
-```
-enable-rcon=true
-rcon.port=25575
-rcon.password=your_rcon_pasword
-```
-
----
-
-##### Contact:
 
 * WWW:            https://github.com/Tiiffi/mcrcon/
-* MAIL:           tiiffi at gmail
+* MAIL:           tiiffi+mcrcon at gmail
-* IRC:            tiiffi @ quakenet
+* ISSUES:         https://github.com/Tiiffi/mcrcon/issues/
-* BUG REPORTS:    https://github.com/Tiiffi/mcrcon/issues/
+
+> [!TIP]
+>When reporting issues, please provide the following information:
+>
+>- Version of mcrcon: Please specify the precise version number
+>- Game: Indicate the specific game server you're using (e.g., Minecraft, Valve Source Engine game, ARK, ...)
+>- Server version: Provide the exact version of the game server
+>- Mods and Extensions: List all mods and extensions used, including their versions
+>- Issue Description: Clearly describe the problem you're encountering and the expected behavior.
+>- Steps to reproduce
+>
+>If you're tech-savvy, consider providing a packet capture file (PCAP). Remember to use a fake password.
 
 ---
 
 ### License
 
 This project is licensed under the zlib License - see the [LICENSE](LICENSE) file for details.
-
----
-
-<sub>Master:</sub> ![Master build](https://api.travis-ci.org/Tiiffi/mcrcon.svg?branch=master)
-<sub>Develop:</sub> ![Develop build](https://api.travis-ci.org/Tiiffi/mcrcon.svg?branch=develop)

create_shortcut.bat

@@ -0,0 +1,31 @@
+@echo off
+@cls
+
+@set /p host="Enter host (default: "127.0.0.1"): "
+@if "%host%"=="" set host=127.0.0.1
+
+@set /p port="Enter port (default: 25575): "
+@if "%port%"=="" set port=25575
+
+@set /p passwd="Enter password: "
+@if "%passwd%"=="" set passwd=
+
+set name=connect_%host%-%port%
+
+@set /p name="Enter shortcut name (default: "%name%.bat"): "
+@if "%name%"=="" set name=connect_%host%-%port%
+
+set command=@mcrcon.exe -t -H %host% -P %port% -p %passwd%
+
+@echo %command% >> %name%.bat
+@echo.
+@echo Command: "%command%"
+@echo.
+@echo Shortcut "%name%.bat" created!
+@echo.
+
+@set "host="
+@set "port="
+@set "passwd="
+
+@pause

launch.bat

@@ -0,0 +1,29 @@
+@echo off
+@cls
+
+@if not exist mcrcon.exe (
+  @echo ERROR: Cannot find "mcrcon.exe". Bailing out!
+  @echo.
+  @pause
+  @exit
+)
+
+@set /p host="Enter host (default: 127.0.0.1): "
+@if "%host%"=="" set host=127.0.0.1
+
+@set /p port="Enter port (default: 25575): "
+@if "%port%"=="" set port=25575
+
+@set /p passwd="Enter password: "
+@if "%passwd%"=="" set passwd=
+
+@echo.
+mcrcon.exe -t -H %host% -P %port% -p %passwd%
+@echo.
+
+@set "host="
+@set "port="
+@set "passwd="
+
+@pause
+

mcrcon.1

@@ -1,7 +1,7 @@
 .\" Process this file with
 .\" groff -man -Tascii mcrcon.1
 .\"
-.TH MCRCON 1 "January 2020" "Version 0.7.1"
+.TH MCRCON 1 "November 2024" "Version 0.7.3"
 .SH NAME 
 mcrcon \- send rcon commands to a Minecraft server
 .SH SYNOPSIS
@@ -11,7 +11,7 @@ options
 commands
 .B ]
 .SH DESCRIPTION
-mcrcon is Minecraft rcon client for remote administration and server maintenance scripts.
+mcrcon is a command-line rcon client intended for remote server administration and maintenance automation.
 .SH OPTIONS
 .IP -H
 Server address (default: localhost)

mcrcon.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012-2020, Tiiffi <tiiffi at gmail>
+ * Copyright (c) 2012-2024, Tiiffi <tiiffi at gmail>
  *
  * This software is provided 'as-is', without any express or implied
  * warranty. In no event will the authors be held liable for any damages
@@ -26,28 +26,22 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <string.h>
+#include <strings.h>
 #include <signal.h>
 #include <errno.h>
 #include <unistd.h>
-#include <limits.h>
+
 
 #ifdef _WIN32
-    // for name resolving on windows
-    // enable this if you get compiler whine about getaddrinfo() on windows
-    //#define _WIN32_WINNT 0x0501
-
-    #include <ws2tcpip.h>
 	#include <winsock2.h>
     #include <windows.h>
+    #include <ws2tcpip.h>
 #else
-    #include <sys/types.h>
     #include <sys/socket.h>
-    #include <netinet/in.h>
-    #include <arpa/inet.h>
     #include <netdb.h>
 #endif
 
-#define VERSION "0.7.1"
+#define VERSION "0.7.3"
 #define IN_NAME "mcrcon"
 #define VER_STR IN_NAME" "VERSION" (built: "__DATE__" "__TIME__")"
 
@@ -57,18 +51,22 @@
 #define RCON_AUTH_RESPONSE      2
 #define RCON_PID                0xBADC0DE
 
-#define DATA_BUFFSIZE 4096
+#define MAX_COMMAND_LENGTH 	4096
+#define DATA_BUFFSIZE		MAX_COMMAND_LENGTH + 2 // plus two null terminators
+#define MAX_PACKET_SIZE		4106 // id (4) + cmd (4) + DATA_BUFFSIZE
+#define MIN_PACKET_SIZE		10   // id (4) + cmd (4) + two empty strings (2)
+
+#define log_error(fmt, ...) fprintf(stderr, fmt,  ##__VA_ARGS__);
 
 // rcon packet structure
-typedef struct _rc_packet {
+typedef struct {
-    int size;
+    int32_t size;
-    int id;
+    int32_t id;
-    int cmd;
+    int32_t cmd;
-    char data[DATA_BUFFSIZE];
+    uint8_t data[DATA_BUFFSIZE];
     // ignoring string2 for now
 } rc_packet;
 
-
 // ===================================
 //  FUNCTION DEFINITIONS              
 // ===================================
@@ -79,10 +77,8 @@ void        net_init_WSA(void);
 #endif
 void        net_close(int sd);
 int         net_connect(const char *host, const char *port);
-int         net_send(int sd, const uint8_t *buffer, size_t size);
+bool        net_send_packet(int sd, rc_packet *packet);
-int         net_send_packet(int sd, rc_packet *packet);
 rc_packet*  net_recv_packet(int sd);
-int         net_clean_incoming(int sd, int size);
 
 // Misc stuff
 void        usage(void);
@@ -94,21 +90,21 @@ int         run_terminal_mode(int sock);
 int         run_commands(int argc, char *argv[]);
 
 // Rcon protocol related functions
-rc_packet*  packet_build(int id, int cmd, char *s1);
+rc_packet*  packet_build(int id, int cmd, char s[static 1]);
 void        packet_print(rc_packet *packet);
-int         rcon_auth(int sock, char *passwd);
+bool        rcon_auth(int sock, char *passwd);
 int         rcon_command(int sock, char *command);
 
-
 // =============================================
 //  GLOBAL VARIABLES
 // =============================================
-static int global_raw_output = 0;
+static int  flag_raw_output = 0;
-static int global_silent_mode = 0;
+static int  flag_silent_mode = 0;
-static int global_disable_colors = 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 int  global_rsock;
-static int global_wait_seconds = 0;
 
 #ifdef _WIN32
   // console coloring on windows
@@ -122,9 +118,12 @@ void exit_proc(void)
 		net_close(global_rsock);
 }
 
-// Check windows & linux behaviour !!!
+// TODO: check exact windows and linux behaviour
-void sighandler(/*int sig*/)
+void sighandler(int sig)
 {
+	if (sig == SIGINT)
+		putchar('\n');
+
 	global_connection_alive = 0;
 	#ifndef _WIN32
 	    exit(EXIT_SUCCESS);
@@ -139,17 +138,17 @@ unsigned int mcrcon_parse_seconds(char *str)
 	long result = strtol(str, &end, 10);
 
 	if (errno != 0) {
-		fprintf(stderr, "-w invalid value.\nerror %d: %s\n", errno, strerror(errno));
+		log_error("-w invalid value.\nerror %d: %s\n", errno, strerror(errno));
 		exit(EXIT_FAILURE);
 	}
 
 	if (end == str) {
-		fprintf(stderr, "-w invalid value (not a number?)\n");
+		log_error("-w invalid value (not a number?)\n");
 		exit(EXIT_FAILURE);
 	}
 
 	if (result <= 0 || result > MAX_WAIT_TIME) {
-		fprintf(stderr, "-w value out of range.\nAcceptable value is 1 - %d (seconds).\n", MAX_WAIT_TIME);
+		log_error("-w value out of range.\nAcceptable value is 1 - %d (seconds).\n", MAX_WAIT_TIME);
 		exit(EXIT_FAILURE);
 	}
 
@@ -178,17 +177,17 @@ int main(int argc, char *argv[])
 			case 'H': host = optarg;                 break;
 			case 'P': port = optarg;                 break;
 			case 'p': pass = optarg;                 break;
-			case 'c': global_disable_colors = 1;    break;
+			case 'c': flag_disable_colors = 1;       break;
-			case 's': global_silent_mode = 1;       break;
+			case 's': flag_silent_mode = 1;          break;
 			case 'i': /* reserved for interp mode */ break;
 			case 't': terminal_mode = 1;             break;
-			case 'r': global_raw_output = 1;        break;
+			case 'r': flag_raw_output = 1;           break;
 			case 'w':
-				global_wait_seconds = mcrcon_parse_seconds(optarg);
+				flag_wait_seconds = mcrcon_parse_seconds(optarg);
 			break;
 
 			case 'v':
-				puts(VER_STR" - https://github.com/Tiiffi/mcrcon");
+				puts(VER_STR);
 				puts("Bug reports:\n\ttiiffi+mcrcon at gmail\n\thttps://github.com/Tiiffi/mcrcon/issues/");
 				exit(EXIT_SUCCESS);
 
@@ -202,11 +201,12 @@ int main(int argc, char *argv[])
 
 	if (pass == NULL) {
 		puts("You must give password (-p password).\nTry 'mcrcon -h' or 'man mcrcon' for help.");
-		return 0;
+		exit(EXIT_FAILURE);
 	}
 
-	if(optind == argc && terminal_mode == 0)
+	if(optind == argc && terminal_mode == 0) {
 		terminal_mode = 1;
+	}
 
 	// safety features to prevent "IO: Connection reset" bug on the server side
 	atexit(&exit_proc);
@@ -228,20 +228,15 @@ int main(int argc, char *argv[])
 
 	// auth & commands
 	if (rcon_auth(global_rsock, pass)) {
-		if (terminal_mode)
+		if (terminal_mode) exit_code = run_terminal_mode(global_rsock);
-			run_terminal_mode(global_rsock);
+		else exit_code = run_commands(argc, argv);
-		else
-			exit_code = run_commands(argc, argv);
 	}
 	else { // auth failed
-		fprintf(stdout, "Authentication failed!\n");
+		log_error("Authentication failed!\n");
 		exit_code = EXIT_FAILURE;
 	}
 
-	net_close(global_rsock);
+	exit(exit_code);
-	global_rsock = -1;
-
-	return exit_code;
 }
 
 void usage(void)
@@ -292,7 +287,7 @@ void net_init_WSA(void)
 
 	int err = WSAStartup(version, &wsadata);
 	if (err != 0) {
-		fprintf(stderr, "WSAStartup failed. Error: %d.\n", err);
+		log_error("WSAStartup failed. Error: %d.\n", err);
 		exit(EXIT_FAILURE);
 	}
 }
@@ -309,7 +304,6 @@ void net_close(int sd)
 	#endif
 }
 
-// Opens and connects socket
 // http://man7.org/linux/man-pages/man3/getaddrinfo.3.html
 // https://bugs.chromium.org/p/chromium/issues/detail?id=44489
 int net_connect(const char *host, const char *port)
@@ -330,11 +324,11 @@ int net_connect(const char *host, const char *port)
 
 	int ret = getaddrinfo(host, port, &hints, &server_info);
 	if (ret != 0) {
-		fprintf(stderr, "Name resolution failed.\n");
+		log_error("Name resolution failed.\n");
 		#ifdef _WIN32
-			fprintf(stderr, "Error %d: %s", ret, gai_strerror(ret));
+			log_error("Error %d: %s", ret, gai_strerror(ret));
 		#else
-			fprintf(stderr, "Error %d: %s\n", ret, gai_strerror(ret));
+			log_error("Error %d: %s\n", ret, gai_strerror(ret));
 		#endif
 
 		exit(EXIT_FAILURE);
@@ -358,9 +352,9 @@ int net_connect(const char *host, const char *port)
 
 	if (p == NULL) {
 		/* TODO (Tiiffi): Check why windows does not report errors */
-		fprintf(stderr, "Connection failed.\n");
+		log_error("Connection failed.\n");
 		#ifndef _WIN32
-			fprintf(stderr, "Error %d: %s\n", errno, strerror(errno));
+			log_error("Error %d: %s\n", errno, strerror(errno));
 		#endif
 
 		freeaddrinfo(server_info);
@@ -371,80 +365,59 @@ int net_connect(const char *host, const char *port)
 	return sd;
 }
 
-int net_send(int sd, const uint8_t *buff, size_t size)
+bool net_send_packet(int sd, rc_packet *packet)
 {
 	size_t sent = 0;
+	size_t size = packet->size + sizeof(int32_t);
 	size_t left = size;
 
-	while (sent < size) {
+	char *p = (char *) packet;
-		int result = send(sd, (const char *) buff + sent, left, 0);
 
-		if (result == -1)
+	while (sent < size) {
-			return -1;
+		ssize_t result = send(sd, p + sent, left, 0);
+
+		if (result == -1) return false;
 
 		sent += result;
 		left -= sent;
 	}
 
-	return 0;
+	return true;
-}
-
-int net_send_packet(int sd, rc_packet *packet)
-{
-	int len;
-	int total = 0;	// bytes we've sent
-	int bytesleft;	// bytes left to send 
-	int ret = -1;
-
-	bytesleft = len = packet->size + sizeof(int);
-
-	while (total < len) {
-		ret = send(sd, (char *) packet + total, bytesleft, 0);
-		if(ret == -1) break;
-		total += ret;
-		bytesleft -= ret;
-	}
-
-	return ret == -1 ? -1 : 1;
 }
 
 rc_packet *net_recv_packet(int sd)
 {
-	int psize;
+	int32_t psize;
-	static rc_packet packet = {0, 0, 0, { 0x00 }};
+	static rc_packet packet = {0};
 
-	// packet.size = packet.id = packet.cmd = 0;
+	ssize_t ret = recv(sd, (char *) &psize, sizeof(psize), 0);
-
-	int ret = recv(sd, (char *) &psize, sizeof(int), 0);
 
 	if (ret == 0) {
-		fprintf(stderr, "Connection lost.\n");
+		log_error("Connection lost.\n");
 		global_connection_alive = 0;
 		return NULL;
 	}
 
-	if (ret != sizeof(int)) {
+	if (ret != sizeof(psize)) {
-		fprintf(stderr, "Error: recv() failed. Invalid packet size (%d).\n", ret);
+		log_error("Error: recv() failed.\n");
 		global_connection_alive = 0;
 		return NULL;
 	}
 
-	if (psize < 10 || psize > DATA_BUFFSIZE) {
+	if (psize < MIN_PACKET_SIZE || psize > MAX_PACKET_SIZE) {
-		fprintf(stderr, "Warning: invalid packet size (%d). Must over 10 and less than %d.\n", psize, DATA_BUFFSIZE);
+		log_error("Error: Invalid packet size (%d).\n", psize);
-
+		global_connection_alive = 0;
-		if(psize > DATA_BUFFSIZE  || psize < 0) psize = DATA_BUFFSIZE;
-		net_clean_incoming(sd, psize);
-
 		return NULL;
 	}
 
 	packet.size = psize;
+	char *p = (char *) &packet;
 
 	int received = 0;
 	while (received < psize) {
-		ret = recv(sd, (char *) &packet + sizeof(int) + received, psize - received, 0);
+		ret = recv(sd, p + sizeof(int32_t) + received, psize - received, 0);
-		if (ret == 0) { /* connection closed before completing receving */
+		if (ret == 0) {
-			fprintf(stderr, "Connection lost.\n");
+			log_error("Connection lost.\n");
 			global_connection_alive = 0;
 			return NULL;
 		}
@@ -455,19 +428,6 @@ rc_packet *net_recv_packet(int sd)
 	return &packet;
 }
 
-int net_clean_incoming(int sd, int size)
-{
-	char tmp[size];
-	int ret = recv(sd, tmp, size, 0);
-
-	if(ret == 0) {
-		fprintf(stderr, "Connection lost.\n");
-		global_connection_alive = 0;
-	}
-
-	return ret;
-}
-
 void print_color(int color)
 {
 	// sh compatible color array
@@ -484,7 +444,7 @@ void print_color(int color)
 		"\033[0;1;30m", /* 08 DGREY     0x38 */
 		"\033[0;1;34m", /* 09 LBLUE     0x39 */
 		"\033[0;1;32m", /* 10 LGREEN    0x61 */
-		"\033[0:1;36m", /* 11 LCYAN     0x62 */
+		"\033[0;1;36m", /* 11 LCYAN     0x62 */
 		"\033[0;1;31m", /* 12 LRED      0x63 */
 		"\033[0;1;35m", /* 13 LPURPLE   0x64 */
 		"\033[0;1;33m", /* 14 YELLOW    0x65 */
@@ -492,8 +452,9 @@ void print_color(int color)
 		"\033[4m"       /* 16 UNDERLINE 0x6e */
 	};
 
-	/* 0x72: 'r' */
+	if (color == 0 || color == 0x72) {
-	if (color == 0 || color == 0x72) fputs("\033[0m", stdout); /* CANCEL COLOR */
+		fputs("\033[0m", stdout); // cancel color
+	}
 	else
 	#endif
 	{
@@ -501,7 +462,7 @@ void print_color(int color)
 		else if (color >= 0x30 && color <= 0x39)
 			color -= 0x30;
 		else if (color == 0x6e)
-			color = 16; /* 0x6e: 'n' */
+			color = 16;
 		else return;
 
 		#ifndef _WIN32
@@ -515,111 +476,177 @@ void print_color(int color)
 // this hacky mess might use some optimizing
 void packet_print(rc_packet *packet)
 {
-	if (global_raw_output == 1) {
+	uint8_t *data = packet->data;
-		for (int i = 0; packet->data[i] != 0; ++i)
-			putchar(packet->data[i]);
 
+	if (flag_raw_output == 1) {
+		for (int i = 0; data[i] != 0; ++i) {
+			putchar(data[i]);
+		}
 		return;
 	}
 
 	int i;
-	int def_color = 0;
+	int default_color = 0;
 
 	#ifdef _WIN32
 		CONSOLE_SCREEN_BUFFER_INFO console_info;
 		if (GetConsoleScreenBufferInfo(console_handle, &console_info) != 0) {
-			def_color = console_info.wAttributes + 0x30;
+			default_color = console_info.wAttributes + 0x30;
-		} else def_color = 0x37;
+		} else default_color = 0x37;
 	#endif
 
 	// colors enabled so try to handle the bukkit colors for terminal
-	if (global_disable_colors == 0) {
+	if (flag_disable_colors == 0) {
-		for (i = 0; (unsigned char) packet->data[i] != 0; ++i) {
+		for (i = 0; data[i] != 0; ++i) {
-			if (packet->data[i] == 0x0A) print_color(def_color);
+			if (data[i] == 0x0A) print_color(default_color);
-			else if((unsigned char) packet->data[i] == 0xc2 && (unsigned char) packet->data[i+1] == 0xa7) {
+			else if(data[i] == 0xc2 && data[i + 1] == 0xa7) {
-				print_color(packet->data[i+=2]);
+				i += 2;
+				print_color(data[i]);
 				continue;
 			}
-			putchar(packet->data[i]);
+			putchar(data[i]);
 		}
-		print_color(def_color); // cancel coloring
+		print_color(default_color); // cancel coloring
 	}
 	// strip colors
 	else {
-		for (i = 0; (unsigned char) packet->data[i] != 0; ++i) {
+		for (i = 0; data[i] != 0; ++i) {
-			if ((unsigned char) packet->data[i] == 0xc2 && (unsigned char) packet->data[i+1] == 0xa7) {
+			if (data[i] == 0xc2 && data[i + 1] == 0xa7) {
 				i += 2;
 				continue;
 			}	
-			putchar(packet->data[i]);
+			putchar(data[i]);
 		}
 	}
 
 	// print newline if string has no newline
-	if (packet->data[i-1] != 10 && packet->data[i-1] != 13) putchar('\n');
+	if (data[i - 1] != 10 && data[i - 1] != 13) {
+		putchar('\n');
+	}
+	fflush(stdout);
 }
 
-rc_packet *packet_build(int id, int cmd, char *s1)
+rc_packet *packet_build(int id, int cmd, char s[static 1])
 {
-	static rc_packet packet = {0, 0, 0, { 0x00 }};
+	static rc_packet packet = {0};
 
-	// size + id + cmd + s1 + s2 NULL terminator
+	// NOTE(Tiiffi): Issue report states that maximum command packet size is 1460 bytes:
-	int s1_len = strlen(s1);
+	//				 https://github.com/Tiiffi/mcrcon/issues/45#issuecomment-1000940814
-	if (s1_len > DATA_BUFFSIZE) {
+	//				 https://mctools.readthedocs.io/en/master/rcon.html
-		fprintf(stderr, "Warning: Command string too long (%d). Maximum allowed: %d.\n", s1_len, DATA_BUFFSIZE);
+	//				 Have to do some testing to confirm!
+
+	int len = strlen(s);
+	if (len > MAX_COMMAND_LENGTH) {
+		log_error("Warning: Command string too long (%d). Maximum allowed: %d.\n", len, MAX_COMMAND_LENGTH);
 		return NULL;
 	}
 
-	packet.size = sizeof(int) * 2 + s1_len + 2;
+	packet.size = sizeof packet.id + sizeof packet.cmd + len + 2;
 	packet.id = id;
 	packet.cmd = cmd;
-	strncpy(packet.data, s1, DATA_BUFFSIZE);
+	if (packet.size > 0) memcpy(packet.data, s, len);
+	packet.data[len] = 0;
+	packet.data[len + 1] = 0;
 
 	return &packet;
 }
 
-int rcon_auth(int sock, char *passwd)
+bool rcon_auth(int sock, char *passwd)
 {
-	int ret;
-
 	rc_packet *packet = packet_build(RCON_PID, RCON_AUTHENTICATE, passwd);
 	if (packet == NULL)
 		return 0;
 
-	ret = net_send_packet(sock, packet);
+	if (!net_send_packet(sock, packet)) {
-	if (!ret)
 		return 0; // send failed
+	}
 
+receive:
 	packet = net_recv_packet(sock);
 	if (packet == NULL)
 		return 0;
 
-	// return 1 if authentication OK
+	/* Valve rcon sends empty "RCON_RESPONSEVALUE" packet before real auth response
-	return packet->id == -1 ? 0 : 1;
+	 * so we have to check packet type and try again if necessary.
+	 */
+	if (packet->cmd != RCON_AUTH_RESPONSE) {
+		global_valve_protocol = true;
+		goto receive;
 	}
 
+	// return true if authentication OK
+	return packet->id == -1 ? false : true;
+}
+
+// TODO: Create function that sends two packets in one send() call
+//       This is important so multipacket guard packet is sent right after real packet
 int rcon_command(int sock, char *command)
 {
 	rc_packet *packet = packet_build(RCON_PID, RCON_EXEC_COMMAND, command);
 	if (packet == NULL) {
-		global_connection_alive = 0;
+		log_error("Error: packet build() failed!\n");
 		return 0;
 	}
 
-	net_send_packet(sock, packet);
+	if (!net_send_packet(sock, packet)) {
+		log_error("Error: net_send_packet() failed!\n");
+		return 0;
+	}
 
+	// Workaround to handle valve multipacket responses
+	// This one does not require using select()
+	packet = packet_build(0xBADA55, 0xBADA55, "");
+	if (packet == NULL) {
+		log_error("Error: packet build() failed!\n");
+		return 0;
+	}
+
+	if (!net_send_packet(sock, packet)) {
+		log_error("Error: net_send_packet() failed!\n");
+		return 0;
+	}
+
+	// initialize stuff for select()
+	fd_set read_fds;
+	FD_ZERO(&read_fds);
+	FD_SET(sock, &read_fds);
+
+	// Set 1.5 second timeout in case there is no response for multipacket guard
+	struct timeval timeout = {0};
+	timeout.tv_sec = 1;
+	timeout.tv_usec = 500000;
+
+	int incoming = 0;
+
+	do {
 		packet = net_recv_packet(sock);
-	if (packet == NULL)
+		if (packet == NULL) {
+			log_error("Error: net_recv_packet() failed!\n");
 			return 0;
+		}
 
-	if (packet->id != RCON_PID)
+		// 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 (!global_silent_mode) {
+		if (packet->id == 0xBADA55) break;
+
+		if (!flag_silent_mode) {
 			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;
 }
 
@@ -631,39 +658,42 @@ int run_commands(int argc, char *argv[])
 		if (!rcon_command(global_rsock, argv[i]))
 			return EXIT_FAILURE;
 
-		if (++i >= argc)
+		i++;
+
+		if (i >= argc)
 			return EXIT_SUCCESS;
 
-		if (global_wait_seconds > 0) {
+		if (flag_wait_seconds > 0) {
 			#ifdef _WIN32
-				Sleep(global_wait_seconds * 1000);
+				Sleep(flag_wait_seconds * 1000);
 			#else
-				sleep(global_wait_seconds);
+				sleep(flag_wait_seconds);
 			#endif
 		}
 	}
 }
 
-// interactive terminal mode
+// terminal mode
 int run_terminal_mode(int sock)
 {
-	int ret = 0;
+	char command[MAX_COMMAND_LENGTH] = {0};
-	char command[DATA_BUFFSIZE] = {0x00};
 
-	puts("Logged in. Type 'quit' or 'exit' to quit.");
+	puts("Logged in.\nType 'Q' or press Ctrl-D / Ctrl-C to disconnect.");
 
 	while (global_connection_alive) {
 		putchar('>');
-		int len = get_line(command, DATA_BUFFSIZE);
+		fflush(stdout);
 
-		if ((strcasecmp(command, "exit") && strcasecmp(command, "quit")) == 0)
+		int len = get_line(command, MAX_COMMAND_LENGTH);
-			break;
+		if (len < 1) continue; 
 	
-		if(command[0] == 'Q' && command[1] == 0)
+		if (strcasecmp(command, "Q") == 0) break;
-			break;
 
-		if(len > 0 && global_connection_alive)
+		if (len > 0 && global_connection_alive) {
-			ret += rcon_command(sock, command);
+			if (!rcon_command(sock, command)) {
+				return EXIT_FAILURE;
+			}
+		}
 
 		/* Special case for "stop" command to prevent server-side bug.
 		 * https://bugs.mojang.com/browse/MC-154617
@@ -675,22 +705,23 @@ int run_terminal_mode(int sock)
 		if (strcasecmp(command, "stop") == 0) {
 			break;
 		}
-
-		command[0] = len = 0;
 	}
 
-	return ret;
+	return EXIT_SUCCESS;
 }
 
 // gets line from stdin and deals with rubbish left in the input buffer
 int get_line(char *buffer, int bsize)
 {
 	char *ret = fgets(buffer, bsize, stdin);
-	if (ret == NULL)
+	if (ret == NULL) {
+		if (ferror(stdin)) {
+			log_error("Error %d: %s\n", errno, strerror(errno));
 			exit(EXIT_FAILURE);
-
+		}
-	if (buffer[0] == 0)
+		putchar('\n');
-		global_connection_alive = 0;
+		exit(EXIT_SUCCESS);
+	}
 
 	// remove unwanted characters from the buffer
 	buffer[strcspn(buffer, "\r\n")] = '\0';