Initial

1 files changed, 171 insertions, 0 deletions

diff --git a/netcatchat.cpp b/netcatchat.cpp
new file mode 100644
index 0000000..8eebda5
--- /dev/null
+++ b/netcatchat.cpp
@@ -0,0 +1,171 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <errno.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+#include <netinet/in.h>
+#include "termio/termio.h"
+
+#include <vector>
+#include <string>
+
+using namespace std;
+
+#define PORT 1234
+
+#define STR_(x) #x
+#define STR(x) STR_(x)
+
+__attribute__((noreturn))
+static void die_perror(const char *msg) {
+	perror(msg);
+	exit(1);
+}
+
+static int create_server_socket(void) {
+	int sock = socket(AF_INET, SOCK_STREAM, 0);
+	if (sock < 0) die_perror("socket");
+
+	int one = 1;
+	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
+
+	struct sockaddr_in name;
+	memset(&name, 0, sizeof name);
+	name.sin_family = AF_INET;
+	name.sin_addr.s_addr = htonl(INADDR_ANY);
+	name.sin_port = htons(PORT);
+	if (bind(sock, (struct sockaddr*)&name, sizeof name) < 0) die_perror("bind");
+
+	if (listen(sock, 16) < 0) die_perror("listen");
+
+	return sock;
+}
+
+static void writeall(int sock, const char *data, size_t len) {
+	size_t cursor = 0;
+	while (cursor < len) {
+		ssize_t nw = write(sock, data + cursor, len - cursor);
+		if (nw <= 0) die_perror("write");
+		cursor += nw;
+	}
+}
+
+static void print_buffer(const char *buffer, size_t len) {
+	Size tsize = querytermsize();
+	if (len + 1 >= tsize.w) {
+		printf("\x1B[2K\x1B[G%s", buffer + len - tsize.w + 1);
+	} else {
+		printf("\x1B[2K\x1B[G%s", buffer);
+	}
+	fflush(stdout);
+}
+
+static void communicate(int sock) {
+	string buffer;
+	string inbuffer;
+
+	initkeyboard(false);
+	atexit(endkeyboard);
+
+	while (true) {
+		Size tsize = querytermsize();
+
+		fd_set inset;
+		FD_ZERO(&inset);
+		FD_SET(0, &inset);
+		FD_SET(sock, &inset);
+		int ret = select(sock + 1, &inset, NULL, NULL, NULL);
+		if (ret < 0) {
+			if (errno == EINTR) continue;
+			die_perror("select");
+		}
+
+		if (FD_ISSET(0, &inset)) {
+			int key = tgetkey();
+			if (key == -1) {  // EOF
+				return;
+			} else if (key == KEY_LF || key == KEY_CR) {
+				buffer.push_back('\n');
+				writeall(sock, buffer.data(), buffer.size());
+				buffer.pop_back();
+				printf("\x1B[2K\x1B[G%s\n", buffer.data());
+				fflush(stdout);
+				buffer.clear();
+			} else if (key == KEY_BACKSPACE) {
+				if (buffer.empty()) {
+					bel();
+				} else {
+					buffer.pop_back();
+					print_buffer(buffer.data(), buffer.size());
+				}
+			} else if (32 <= key) {
+				buffer.push_back(key);
+				print_buffer(buffer.data(), buffer.size());
+			} else {
+				bel();
+			}
+		}
+
+		if (FD_ISSET(sock, &inset)) {
+			size_t prevsize = inbuffer.size();
+			inbuffer.resize(prevsize + 1024);
+
+			ssize_t nr = read(sock, (void*)(inbuffer.data() + prevsize), 1024);
+			if (nr < 0) die_perror("read");
+			if (nr == 0) return;  // eof
+
+			inbuffer.resize(prevsize + nr);
+			for (size_t idx; (idx = inbuffer.find('\n')) != string::npos; ) {
+				inbuffer[idx] = '\0';
+				printf("\x1B[2K\x1B[G%s\n", inbuffer.data());
+				inbuffer.erase(inbuffer.begin(), inbuffer.begin() + idx + 1);
+			}
+
+			print_buffer(buffer.data(), buffer.size());
+		}
+	}
+}
+
+int main(int argc, char **argv) {
+	if (argc == 2 && strcmp(argv[1], "-s") == 0) {
+		int lsock = create_server_socket();
+
+		printf("Listening on port %d\n", PORT);
+		int sock = accept(lsock, NULL, NULL);
+		if (sock == -1) die_perror("accept");
+
+		communicate(sock);
+		close(sock);
+	} else if (argc == 2) {
+		struct addrinfo *addrs;
+		struct addrinfo hints;
+		memset(&hints, 0, sizeof hints);
+		hints.ai_family = AF_UNSPEC;
+		hints.ai_socktype = SOCK_STREAM;
+		hints.ai_protocol = IPPROTO_TCP;
+		if (getaddrinfo(argv[1], STR(PORT), &hints, &addrs) < 0) die_perror("getaddrinfo");
+
+		int sock = socket(AF_INET, SOCK_STREAM, 0);
+		if (sock < 0) die_perror("socket");
+
+		bool success = false;
+		for (struct addrinfo *addr = addrs; addr; addr = addr->ai_next) {
+			if (connect(sock, addr->ai_addr, addr->ai_addrlen) < 0) continue;
+			success = true;
+			break;
+		}
+
+		if (!success) {
+			perror("connect");
+			freeaddrinfo(addrs);
+			exit(1);
+		}
+
+		communicate(sock);
+		close(sock);
+	}
+}