A very messy demo of a broadcast

2026-01-04 16:24:36 +01:00
commit 36ae15c320
5 changed files with 369 additions and 0 deletions
@@ -0,0 +1,177 @@
+#include "commands.h"
+#include "sys/ipc.h"
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/msg.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define send(queue_id, msgbuf_ptr)                                             \
+  msgsnd(queue_id, msgbuf_ptr, sizeof(*(msgbuf_ptr)) - sizeof(long), 0)
+
+typedef struct {
+  char *id;
+  bool logged_in;
+  char *muted_clients;
+  char nickname[16];
+  int queue_id;
+} Client;
+
+typedef struct {
+  Client **clients;
+  char name[16];
+  int client_count;
+} Group;
+
+int main(int argc, char **argv) {
+  // TODO: Load config file with clients and groups
+  int client_count = 1;
+  int group_count = 3;
+  Client *clients = malloc(sizeof(Client) * 9);
+  Group *groups = malloc(sizeof(Group) * 3);
+
+  clients[0] = (Client){
+      .id = "the_only_one",
+      .logged_in = false,
+      .muted_clients = NULL,
+      .nickname = "Kregielnia",
+  };
+
+  // key_t key = ftok(argv[0], 555);
+  int server_queue_id = msgget(IPC_PRIVATE, 0666 | IPC_CREAT);
+
+  if (server_queue_id == -1) {
+    perror("msgget failed");
+    return 1;
+  }
+
+  int id_file_handle =
+      open("/home/piotr/server_queue_id", O_WRONLY | O_CREAT | O_TRUNC, 0666);
+  if (!id_file_handle) {
+    perror("Failed to open file");
+    return 1;
+  }
+
+  if (write(id_file_handle, &server_queue_id, sizeof(int)) == -1) {
+    perror("Failed to write server queue id to file");
+    return 1;
+  }
+  close(id_file_handle);
+
+  // TODO: Fork here, for the heartbeat process than can sleep
+  msgbuf_t msgbuf;
+  while (1) {
+    // Read from the ipc, then handle the command
+    int read_status =
+        msgrcv(server_queue_id, &msgbuf, sizeof(msgbuf) - sizeof(long), 0, 0);
+
+    switch (msgbuf.mtype) {
+    case Login:
+      printf("Received login request for id: %s\n", msgbuf.command);
+      Client *client = NULL;
+      for (int i = 0; i < 1; i++) {
+        if (strncmp(clients[i].id, msgbuf.command, COMMAND_LENGTH) == 0) {
+          client = &clients[i];
+          break;
+        }
+      }
+
+      // Reuse the buffer to get the client's message queue id
+      int msg_queue_id = atoi(msgbuf.message);
+      if (client == NULL) {
+        printf("User not found: %s\n", msgbuf.command);
+        msgbuf_t response = {
+            .mtype = Login,
+            .stype = ERR_USER_NOT_FOUND,
+        };
+
+        send(msg_queue_id, &response);
+        continue;
+      }
+
+      if (client->logged_in) {
+        printf("User already logged in: %s\n", msgbuf.command);
+        msgbuf_t response = {
+            .mtype = Login,
+            .stype = ERR_ALREADY_LOGGED_IN,
+        };
+
+        send(msg_queue_id, &response);
+        continue;
+      }
+
+      client->logged_in = true;
+      client->queue_id = msg_queue_id;
+      msgbuf_t response = {
+          .mtype = Login,
+          .stype = ACK_ACCEPTED,
+      };
+      printf("User accepted: %s\n", msgbuf.command);
+      send(msg_queue_id, &response);
+      break;
+    case Message:
+
+      printf("Recieved message, checking which client\n");
+      // Find the client that sent the message then forward it to all the
+      // specified recipients
+      client = NULL;
+      for (int i = 0; i < client_count; i++) {
+          if (strncmp(clients[i].id, msgbuf.sender, COMMAND_LENGTH) == 0) {
+            client = &clients[i];
+            break;
+          }
+      }
+
+      printf("Received message from client id %s: %s\n", msgbuf.sender,
+             msgbuf.message);
+
+      if (client == NULL || !client->logged_in) {
+        // Client not found or not logged in
+        printf("Client not found or not logged in");
+        msgbuf_t response = {
+            .mtype = Message,
+            .stype = ERR_NOT_LOGGED_IN,
+        };
+        send(read_status, &response);
+        continue;
+      }
+
+      printf("Forwarding message: %s\n", msgbuf.message);
+
+      // TODO: Find the actual recipients, for now broadcast
+      msgbuf_t forward_msg = {
+          .mtype = Message,
+      };
+      strncpy(forward_msg.message, msgbuf.message, MESSAGE_LENGTH);
+      // Yes, the client sending the message also receives it
+      for (int i = 0; i < client_count; i++) {
+        if (clients[i].logged_in) {
+          send(clients[i].queue_id, &forward_msg);
+        }
+      }
+
+      forward_msg.stype = ACK_ACCEPTED;
+      forward_msg.mtype = Signal;
+      send(client->queue_id, &forward_msg);
+
+      // TODO: Accepted and Delivered ack
+      break;
+    case Logout:
+    case Hearbeat:
+    case List_clients:
+      break;
+    case Mute:
+    case Unmute:
+      break;
+    case Signal:
+      // Signals are sent from server to client, not the other way around
+      // so we ignore them here lol
+      break;
+    }
+  }
+
+  return 0;
+}