TheCloneArmy/mcrcon
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Perform endianness conversion when running on a big-endian host

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Tiiffi
2025-11-27 06:58:04 +02:00
parent cabddcb185
commit 8963c9c2a7
1 changed files with 64 additions and 68 deletions
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112
mcrcon.c
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@@ -62,8 +62,6 @@
#define MAX_WAIT_TIME 600
#define log_error(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__);
// rcon packet structure
typedef struct {
int32_t size;
@@ -94,6 +92,14 @@ int get_line(char *buffer, int len);
int run_terminal_mode(int sock);
int run_commands(int argc, char *argv[]);
// NOTE: These are GCC and Clang specific macros.
#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define MACHINE_IS_BIG_ENDIAN 1
static inline uint32_t bswap32(uint32_t n);
#else
#define bswap32(x) (x)
#endif
// Rcon protocol related functions
rc_packet* packet_build(int id, int cmd, char s[static 1]);
void packet_print(rc_packet *packet);
@@ -106,7 +112,7 @@ int rcon_command(int sock, char *command);
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 unsigned int flag_wait_seconds = 0;
static int global_connection_alive = 1;
static bool global_valve_protocol = false;
static bool global_minecraft_newline_fix = false;
@@ -151,19 +157,16 @@ 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));
fprintf(stderr, "-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");
fprintf(stderr, "-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);
fprintf(stderr, "-w value out of range.\nAcceptable value is 1 - %d (seconds).\n", MAX_WAIT_TIME);
exit(EXIT_FAILURE);
}
@@ -235,7 +238,6 @@ int main(int argc, char *argv[])
console_input_handle = GetStdHandle(STD_INPUT_HANDLE);
if (console_input_handle == INVALID_HANDLE_VALUE || console_input_handle == NULL) {
fprintf(stderr, "Error: Failed to get console input handle.\n");
fprintf(stderr, "Error: Failed to get console input handle.\n");
exit(EXIT_FAILURE);
}
@@ -263,7 +265,6 @@ int main(int argc, char *argv[])
else exit_code = run_commands(argc, argv);
}
else { // auth failed
fprintf(stderr, "Authentication failed!\n");
fprintf(stderr, "Authentication failed!\n");
exit_code = EXIT_FAILURE;
}
@@ -319,7 +320,6 @@ void net_init_WSA(void)
int err = WSAStartup(version, &wsadata);
if (err != 0) {
fprintf(stderr, "WSAStartup failed. Error: %d.\n", err);
fprintf(stderr, "WSAStartup failed. Error: %d.\n", err);
exit(EXIT_FAILURE);
}
@@ -357,13 +357,10 @@ 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");
fprintf(stderr, "Name resolution failed.\n");
#ifdef _WIN32
fprintf(stderr, "Error %d: %s", ret, gai_strerror(ret));
fprintf(stderr, "Error %d: %s", ret, gai_strerror(ret));
#else
fprintf(stderr, "Error %d: %s\n", ret, gai_strerror(ret));
fprintf(stderr, "Error %d: %s\n", ret, gai_strerror(ret));
#endif
@@ -388,10 +385,8 @@ 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");
fprintf(stderr, "Connection failed.\n");
#ifndef _WIN32
fprintf(stderr, "Error %d: %s\n", errno, strerror(errno));
fprintf(stderr, "Error %d: %s\n", errno, strerror(errno));
#endif
@@ -406,17 +401,15 @@ int net_connect(const char *host, const char *port)
bool net_send_packet(int sd, rc_packet *packet)
{
size_t sent = 0;
size_t size = packet->size + sizeof(int32_t);
size_t size = (size_t) packet->size + (ssize_t) sizeof(int32_t);
size_t left = size;
char *p = (char *) packet;
while (sent < size) {
ssize_t result = send(sd, p + sent, left, 0);
if (result == -1) return false;
sent += result;
sent += (size_t) result;
left -= sent;
}
@@ -443,27 +436,21 @@ rc_packet *net_recv_packet(int sd)
int32_t psize;
static rc_packet packet = {0};
ssize_t ret = recv(sd, (char *) &psize, sizeof(psize), 0);
ssize_t ret = net_recv_all(sd, &psize, sizeof(psize));
if (ret == 0) {
fprintf(stderr, "Connection lost.\n");
fprintf(stderr, "Connection lost.\n");
global_connection_alive = 0;
return NULL;
}
else if (ret < 0) {
fprintf(stderr, "Error: recv() failed with errno: %d.\n", errno);
global_connection_alive = 0;
return NULL;
}
// TODO: Handle -1 return value which indicates error
// Data may also be fragmented so it's not guaranteed that
// we receive 4 bytes in one recv() call
if (ret != sizeof(psize)) {
fprintf(stderr, "Error: recv() failed.");
fprintf(stderr, "Error: recv() failed.");
global_connection_alive = 0;
return NULL;
}
psize = bswap32(psize);
if (psize < MIN_PACKET_SIZE || psize > MAX_PACKET_SIZE) {
fprintf(stderr, "Error: Invalid packet size (%d).\n", psize);
fprintf(stderr, "Error: Invalid packet size (%d).\n", psize);
global_connection_alive = 0;
return NULL;
@@ -472,24 +459,26 @@ rc_packet *net_recv_packet(int sd)
packet.size = psize;
char *p = (char *) &packet;
int received = 0;
while (received < psize) {
ret = recv(sd, p + sizeof(int32_t) + received, psize - received, 0);
ret = net_recv_all(sd, p + sizeof(int32_t), packet.size);
if (ret == 0) {
log_error("Connection lost.\n");
fprintf(stderr, "Connection lost.\n");
global_connection_alive = 0;
return NULL;
}
else if (ret < 0) {
fprintf(stderr, "Error: recv() failed with errno: %d\n", errno);
global_connection_alive = 0;
return NULL;
}
received += ret;
}
packet.id = bswap32(packet.id);
packet.cmd = bswap32(packet.cmd);
return &packet;
}
/* NOTE: At least Bukkit/Spigot servers are sending formatting via rcon but not sure how common this
* behaviour is. This implementation tries to print colors but is omitting "bold" in "bright" colors
* because bold tag should be manually reset and Bukkit/Spigot is not doing this.
* behaviour is. This implementation tries to print colors correctly.
* References: https://minecraft.fandom.com/wiki/Formatting_codes
* https://en.wikipedia.org/wiki/ANSI_escape_code
*/
@@ -614,19 +603,19 @@ rc_packet *packet_build(int id, int cmd, char s[static 1])
// https://mctools.readthedocs.io/en/master/rcon.html
// Have to do some testing to confirm!
int len = strlen(s);
size_t len = strlen(s);
if (len > MAX_COMMAND_LENGTH) {
log_error("Warning: Command string too long (%d). Maximum allowed: %d.\n", len, MAX_COMMAND_LENGTH);
fprintf(stderr, "Warning: Command string too long (%zu). Maximum allowed: %d.\n", len, MAX_COMMAND_LENGTH);
return NULL;
}
packet.size = sizeof packet.id + sizeof packet.cmd + len + 2;
packet.id = id;
packet.cmd = cmd;
if (packet.size > 0) memcpy(packet.data, s, len);
int32_t packet_size = (int32_t) (sizeof packet.id + sizeof packet.cmd + len + 2);
if (packet_size > 0) memcpy(packet.data, s, len);
packet.data[len] = 0;
packet.data[len + 1] = 0;
packet.size = bswap32(packet_size);
packet.id = bswap32(id);
packet.cmd = bswap32(cmd);
return &packet;
}
@@ -665,13 +654,11 @@ int rcon_command(int sock, char *command)
rc_packet *packet = packet_build(RCON_PID, RCON_EXEC_COMMAND, command);
if (packet == NULL) {
fprintf(stderr, "Error: packet build() failed!\n");
fprintf(stderr, "Error: packet build() failed!\n");
return 0;
}
if (!net_send_packet(sock, packet)) {
fprintf(stderr, "Error: net_send_packet() failed!\n");
fprintf(stderr, "Error: net_send_packet() failed!\n");
return 0;
}
@@ -679,13 +666,11 @@ int rcon_command(int sock, char *command)
// workaround to handle valve style multipacket responses
packet = packet_build(0xBADA55, 0xBADA55, "");
if (packet == NULL) {
fprintf(stderr, "Error: packet build() failed!\n");
fprintf(stderr, "Error: packet build() failed!\n");
return 0;
}
if (!net_send_packet(sock, packet)) {
fprintf(stderr, "Error: net_send_packet() failed!\n");
fprintf(stderr, "Error: net_send_packet() failed!\n");
return 0;
}
@@ -706,14 +691,12 @@ int rcon_command(int sock, char *command)
do {
packet = net_recv_packet(sock);
if (packet == NULL) {
fprintf(stderr, "Error: net_recv_packet() failed!\n");
fprintf(stderr, "Error: net_recv_packet() failed!\n");
return 0;
}
// Check for packet id and multipacket guard id
if (packet->id != RCON_PID && packet->id != 0xBADA55) {
fprintf(stderr, "Error: invalid packet id!\n");
fprintf(stderr, "Error: invalid packet id!\n");
return 0;
}
@@ -736,7 +719,6 @@ int rcon_command(int sock, char *command)
int result = select(sock + 1, &read_fds, NULL, NULL, &timeout);
if (result == -1) {
fprintf(stderr, "Error: select() failed!\n");
fprintf(stderr, "Error: select() failed!\n");
return 0;
}
@@ -809,12 +791,15 @@ int run_terminal_mode(int sock)
// TODO: More Windows side testing!
int result = recv(sock, tmp, sizeof(tmp), MSG_PEEK | 0);
#else
int result = recv(sock, tmp, sizeof(tmp), MSG_PEEK | MSG_DONTWAIT);
ssize_t result = recv(sock, tmp, sizeof(tmp), MSG_PEEK | MSG_DONTWAIT);
#endif
if (result == 0) {
break; // Connection closed
}
// TODO: Check for return values and errors!
if (result < 0) { // NOTE: Maybe more detailed error handling?
fprintf(stderr, "Error: recv() failed with errno: %d\n", errno);
exit(EXIT_FAILURE);
}
}
}
@@ -852,14 +837,12 @@ char *windows_getline(char *buf, int size)
int bytes_needed = WideCharToMultiByte(CP_UTF8, 0, wide_buffer, -1, NULL, 0, NULL, NULL);
if (bytes_needed <= 0 || bytes_needed > size) {
fprintf(stderr, "Widechar to UTF-8 conversion failed.\n");
fprintf(stderr, "Widechar to UTF-8 conversion failed.\n");
exit(EXIT_FAILURE);
}
int result = WideCharToMultiByte(CP_UTF8, 0, wide_buffer, -1, buf, size, NULL, NULL);
if (result == 0) {
fprintf(stderr, "Widechar to UTF-8 conversion failed.\n");
fprintf(stderr, "Widechar to UTF-8 conversion failed.\n");
exit(EXIT_FAILURE);
}
@@ -879,7 +862,6 @@ int get_line(char *buffer, int bsize)
if (ret == NULL) {
if (ferror(stdin)) {
fprintf(stderr, "Error %d: %s\n", errno, strerror(errno));
fprintf(stderr, "Error %d: %s\n", errno, strerror(errno));
exit(EXIT_FAILURE);
}
@@ -890,7 +872,7 @@ int get_line(char *buffer, int bsize)
// remove unwanted characters from the buffer
buffer[strcspn(buffer, "\r\n")] = '\0';
int len = strlen(buffer);
int len = (int) strlen(buffer);
if (len == bsize - 1) {
int ch;
@@ -899,3 +881,17 @@ int get_line(char *buffer, int bsize)
return len;
}
#if MACHINE_IS_BIG_ENDIAN
static inline uint32_t bswap32(uint32_t n)
{
#if defined(__GNUC__) || defined(__clang__)
return __builtin_bswap32(n);
#else
return ((n & 0xFF000000u) >> 24) |
((n & 0x00FF0000u) >> 8) |
((n & 0x0000FF00u) << 8) |
((n & 0x000000FFu) << 24);
#endif
}
#endif