massive feat: added a GDB stub for debugging

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

src/util/tcp_server.cc

@@ -0,0 +1,80 @@
+#include "tcp_server.hh"
+
+#include <cstring>
+#include <format>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+namespace net {
+TcpServer::TcpServer()
+  : server_fd(0)
+  , client_fd(0) {}
+
+TcpServer::~TcpServer() {
+    close(server_fd);
+    close(client_fd);
+}
+
+bool
+TcpServer::client_waiting() {
+    int count = 0;
+    ioctl(client_fd, FIONREAD, &count);
+    return static_cast<bool>(count);
+}
+
+void
+TcpServer::run() {
+    socklen_t cli_addr_size = sizeof(client_addr);
+
+    client_fd = ::accept(
+      server_fd, reinterpret_cast<sockaddr*>(&client_addr), &cli_addr_size);
+
+    if (client_fd == -1)
+        throw std::runtime_error("accept failed");
+}
+
+void
+TcpServer::start(uint port) {
+    server_fd = socket(PF_INET, SOCK_STREAM, 0);
+    if (server_fd == -1) {
+        throw std::runtime_error("creating socket failed");
+    }
+
+    int option = 1;
+    setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
+
+    std::memset(&server_addr, 0, sizeof(server_addr));
+    server_addr.sin_family      = PF_INET;
+    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
+    server_addr.sin_port        = htons(port);
+
+    if (::bind(server_fd,
+               reinterpret_cast<sockaddr*>(&server_addr),
+               sizeof(server_addr)) == -1) {
+        throw std::runtime_error("binding socket failed");
+    }
+    if (::listen(server_fd, 1) == -1) {
+        throw std::runtime_error("listening failed");
+    }
+}
+
+void
+TcpServer::send(std::string msg) {
+    if (::send(client_fd, msg.data(), msg.length(), 0) == -1) {
+        throw std::runtime_error(
+          std::format("failed to send message: {}\n", strerror(errno)));
+    }
+}
+
+std::string
+TcpServer::receive(uint length) {
+    char msg[MAX_PACKET_SIZE];
+    ssize_t num_bytes = recv(client_fd, msg, length, 0);
+    msg[length]       = '\0';
+    if (num_bytes < 0) {
+        throw std::runtime_error(
+          std::format("failed to receive messages: {}\n", strerror(errno)));
+    }
+    return std::string(msg);
+}
+}