more error handling

src/main.c

@@ -6,6 +6,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <stdint.h>
+#include <errno.h>
 
 const char *LOCALHOST = "127.0.0.1";
 
@@ -47,7 +48,12 @@ int rcon_connect(int port) {
     memset(&server_addr, 0, sizeof(server_addr));
     server_addr.sin_family = AF_INET;
     server_addr.sin_port = htons(port);
-    inet_pton(AF_INET, LOCALHOST, &server_addr.sin_addr);
+
+    if (inet_pton(AF_INET, LOCALHOST, &server_addr.sin_addr) <= 0) {
+        perror("invalid address");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
 
     if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
         perror("connection failed");
@@ -61,24 +67,68 @@ int rcon_connect(int port) {
 
 void send_packet(int sockfd, int32_t id, int32_t type, const char *body) {
     int body_len = strlen(body);
-    int32_t size = 10 + body_len; // 4 (id) + 4 (type) + body + 2 (null terminators)
+    int32_t size = 10 + body_len;
 
-    send(sockfd, &size, sizeof(int32_t), 0);
-    send(sockfd, &id, sizeof(int32_t), 0);
-    send(sockfd, &type, sizeof(int32_t), 0);
-    send(sockfd, body, body_len + 1, 0);
+    printf("DEBUG: sending packet - id=%d, type=%d, size=%d, body='%s'\n",
+           id, type, size, body);
+
+    if (send(sockfd, &size, sizeof(int32_t), 0) < 0) {
+        perror("send size failed");
+        return;
+    }
+    if (send(sockfd, &id, sizeof(int32_t), 0) < 0) {
+        perror("send id failed");
+        return;
+    }
+    if (send(sockfd, &type, sizeof(int32_t), 0) < 0) {
+        perror("send type failed");
+        return;
+    }
+    if (send(sockfd, body, body_len + 1, 0) < 0) {
+        perror("send body failed");
+        return;
+    }
     const char null = '\0';
-    send(sockfd, &null, 1, 0);
+    if (send(sockfd, &null, 1, 0) < 0) {
+        perror("send null failed");
+        return;
+    }
+
+    printf("DEBUG: packet sent successfully\n");
 }
 
 int recv_packet(int sockfd, rcon_packet_t *packet) {
-    if (recv(sockfd, &packet->size, sizeof(int32_t), 0) <= 0) { return -1; }
-    if (recv(sockfd, &packet->id, sizeof(int32_t), 0) <= 0) { return -1; }
-    if (recv(sockfd, &packet->type, sizeof(int32_t), 0) <= 0) { return -1; }
+    ssize_t bytes;
+
+    bytes = recv(sockfd, &packet->size, sizeof(int32_t), 0);
+    if (bytes <= 0) {
+        if (bytes == 0) {
+            fprintf(stderr, "connection closed by server (no data received)\n");
+        } else {
+            perror("recv size failed");
+        }
+        return -1;
+    }
+
+    printf("DEBUG: received size=%d\n", packet->size);
+
+    bytes = recv(sockfd, &packet->id, sizeof(int32_t), 0);
+    if (bytes <= 0) {
+        perror("recv id failed");
+        return -1;
+    }
+
+    bytes = recv(sockfd, &packet->type, sizeof(int32_t), 0);
+    if (bytes <= 0) {
+        perror("recv type failed");
+        return -1;
+    }
 
     int body_size = packet->size - 10;
-    if (body_size > 0 && body_size < sizeof(packet->body)) {
-        if (recv(sockfd, packet->body, body_size + 2, 0) <= 0) {
+    if (body_size > 0 && body_size < (int)sizeof(packet->body)) {
+        bytes = recv(sockfd, packet->body, body_size + 2, 0);
+        if (bytes <= 0) {
+            perror("recv body failed");
             return -1;
         }
         packet->body[body_size] = '\0';
@@ -86,20 +136,34 @@ int recv_packet(int sockfd, rcon_packet_t *packet) {
         packet->body[0] = '\0';
     }
 
+    printf("DEBUG: received packet - id=%d, type=%d, body='%s'\n",
+           packet->id, packet->type, packet->body);
+
     return 0;
 }
 
 int rcon_authenticate(int sockfd, const char *password) {
+    printf("authenticating with password: '%s' (length=%zu)\n",
+           password, strlen(password));
+
     send_packet(sockfd, 1, SERVERDATA_AUTH, password);
 
-    rcon_packet_t response;
-    if (recv_packet(sockfd, &response) < 0) {
-        perror("failed to receive auth response\n");
+    printf("waiting for auth responses...\n");
+
+    rcon_packet_t response1;
+    if (recv_packet(sockfd, &response1) < 0) {
+        fprintf(stderr, "failed to receive first auth response\n");
         return -1;
     }
 
-    if (response.id == -1) {
-        perror("authentication failed\n");
+    rcon_packet_t response2;
+    if (recv_packet(sockfd, &response2) < 0) {
+        fprintf(stderr, "failed to receive second auth response\n");
+        return -1;
+    }
+
+    if (response2.id == -1) {
+        fprintf(stderr, "authentication failed - invalid password\n");
         return -1;
     }
 
@@ -117,11 +181,10 @@ char* rcon_command_multipacket(int sockfd, const char *command) {
     send_packet(sockfd, cmd_id, SERVERDATA_EXECCOMMAND, command);
     send_packet(sockfd, dummy_id, SERVERDATA_EXECCOMMAND, "");
 
-    // read packets until we get the dummy response
     while (1) {
         rcon_packet_t response;
         if (recv_packet(sockfd, &response) < 0) {
-            perror("failed to receive command response\n");
+            fprintf(stderr, "failed to receive command response\n");
             return NULL;
         }
         if (response.id == dummy_id) {
@@ -140,11 +203,15 @@ int main(int argc, char **argv) {
     const char *password = getenv("RCON_PASSWORD");
 
     if (password == NULL) {
-        perror("error: RCON_PASSWORD environment variable not set.\n");
+        fprintf(stderr, "error: RCON_PASSWORD environment variable not set.\n");
         exit(EXIT_FAILURE);
     }
 
+    printf("=== RCON Configuration ===\n");
     printf("port: %d\n", PORT_NUM);
+    printf("password: '%s'\n", password);
+    printf("password length: %zu bytes\n", strlen(password));
+    printf("==========================\n\n");
 
     int sockfd = rcon_connect(PORT_NUM);
 
@@ -154,13 +221,14 @@ int main(int argc, char **argv) {
     }
 
     const char *get_player_positions_cmd = "execute as @a run data get entity @s Pos";
+    printf("\nexecuting command: %s\n", get_player_positions_cmd);
     char *response = rcon_command_multipacket(sockfd, get_player_positions_cmd);
 
     if (response) {
         printf("\n=== player positions ===\n");
         printf("%s\n", response);
     } else {
-        perror("failed to get player positions\n");
+        fprintf(stderr, "failed to get player positions\n");
     }
 
     close(sockfd);