commit 72f97117e73bee6ec6785245e615405abe7d5538
Author: Masahiko AMANO <hiko-19@ya.ru>
Date:   Fri Oct 18 20:28:30 2024 +0300

    init

diff --git a/aiken.c b/aiken.c
new file mode 100644
index 0000000..14ce11d
--- /dev/null
+++ b/aiken.c
@@ -0,0 +1,318 @@
+#include <stdlib.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+#include <getopt.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#define PORT_UDP 46226
+#define PORT_TCP 46227
+
+#define BUF_SIZE 1024
+
+char *basename(const char *path) {
+	char *res = strrchr(path, '/');
+	return (res == NULL) ? path : (res + 1);
+}
+
+void token_generate(char *dst) {
+	sprintf(dst, "%04x", (uint16_t) time(NULL));
+}
+
+void share(const char *path) {
+	FILE *file = fopen(path, "rb");
+	if (file == NULL) {
+		perror("Failed to open file");
+		exit(errno);
+	}
+	char token[5];
+	int udp_sock = socket(AF_INET, SOCK_DGRAM, 0), sock_option = 1;
+	if (udp_sock < 0) {
+		perror("Failed to initialize UDP socket");
+		fclose(file);
+		exit(errno);
+	}
+	if (setsockopt(udp_sock, SOL_SOCKET, SO_REUSEADDR, &sock_option, sizeof(sock_option)) < 0) {
+		perror("Failed to set UDP socket options");
+		exit(errno);
+	}
+	struct sockaddr_in listen_addr, receiver_addr;
+	socklen_t addr_len = sizeof(receiver_addr);
+	bzero(&listen_addr, sizeof(listen_addr));
+	listen_addr.sin_family = AF_INET;
+	listen_addr.sin_addr.s_addr = INADDR_ANY;
+	listen_addr.sin_port = htons(PORT_UDP);
+	if (bind(udp_sock, (struct sockaddr *) &listen_addr, sizeof(listen_addr)) < 0) {
+		perror("Failed to bind UDP socket");
+		fclose(file);
+		close(udp_sock);
+		exit(errno);
+	}
+	token_generate(token);
+	printf("Successfully shared!\nToken: %s\n\n", token);
+	char buffer[BUF_SIZE];
+	char *filename = basename(path);
+	int tcp_server_sock, tcp_client_sock;
+	printf("Waiting for request...\n");
+	// recieve request from receiver
+	if (recvfrom(udp_sock, buffer, 4, 0, (struct sockaddr *) &receiver_addr, &addr_len) < 4) {
+		printf("Got invalid request from %s\n", inet_ntoa(receiver_addr.sin_addr));
+		fclose(file);
+		close(udp_sock);
+		exit(errno);
+	}
+	// check request token
+	if (memcmp(buffer, token, 4) != 0) {
+		printf("Got invalid token from %s\n", inet_ntoa(receiver_addr.sin_addr));
+		// send NO packet which tells that request is rejected
+		if (sendto(udp_sock, "NO", 2, 0, (struct sockaddr *) &receiver_addr, addr_len) < 2) {
+			perror("Failed to send NO packet");
+		}
+		fclose(file);
+		close(udp_sock);
+		exit(errno);
+	}
+	printf("Got request from %s\n", inet_ntoa(receiver_addr.sin_addr));
+	// create a TCP socket to send file
+	tcp_server_sock = socket(AF_INET, SOCK_STREAM, 0);
+	if (tcp_server_sock < 0) {
+		perror("Failed to initialize TCP socket");
+		fclose(file);
+		close(udp_sock);
+		exit(errno);
+	}
+	if (setsockopt(tcp_server_sock, SOL_SOCKET, SO_REUSEADDR, &sock_option, sizeof(sock_option)) < 0) {
+		perror("Failed to set TCP socket options");
+		exit(errno);
+	}
+	listen_addr.sin_port = htons(PORT_TCP);
+	if (bind(tcp_server_sock, (struct sockaddr *) &listen_addr, addr_len) < 0) {
+		perror("Failed to bind TCP socket");
+		fclose(file);
+		close(udp_sock);
+		close(tcp_server_sock);
+		exit(errno);
+	}
+	if (listen(tcp_server_sock, 1) < 0) {
+		perror("Failed to listen to TCP socket");
+		fclose(file);
+		close(udp_sock);
+		close(tcp_server_sock);
+		exit(errno);
+	}
+	// send OK packet which tells that we are ready to send file
+	if (sendto(udp_sock, "OK", 2, 0, (struct sockaddr *) &receiver_addr, addr_len) < 2) {
+		perror("Failed to send OK packet");
+		fclose(file);
+		close(udp_sock);
+		close(tcp_server_sock);
+		exit(errno);
+	}
+	close(udp_sock);
+	printf("Waiting for reciever connection...\n");
+	// wait for receiver connection
+	if ((tcp_client_sock = accept(tcp_server_sock, (struct sockaddr *) &receiver_addr, &addr_len)) < 0) {
+		perror("Failed to accept receiver connection");
+		fclose(file);
+		close(tcp_server_sock);
+		exit(errno);
+	}
+	printf("Receiver connected, sending...\n");
+	// send file name
+	if (send(tcp_client_sock, filename, strlen(filename) + 1, 0) < strlen(filename) + 1) {
+		perror("Failed to send file name");
+		fclose(file);
+		close(tcp_client_sock);
+		close(tcp_server_sock);
+		exit(errno);
+	}
+	// send file data
+	ssize_t rcount;
+	while ((rcount = fread(buffer, 1, BUF_SIZE, file)) > 0) {
+		if (send(tcp_client_sock, buffer, rcount, 0) != rcount) {
+			perror("Failed to send file data");
+			fclose(file);
+			close(tcp_client_sock);
+			close(tcp_server_sock);
+			exit(errno);
+		}
+	}
+	close(tcp_client_sock);
+	close(tcp_server_sock);
+	printf("Sending complete!\n");
+}
+
+void get(const char *token, const char *path) {
+	size_t abspath_len = strlen(path) + 1;
+	if (abspath_len > PATH_MAX) {
+		printf("Invalid path: too long\n");
+		exit(1);
+	}
+	char abspath[PATH_MAX];
+	strcpy(abspath, path);
+	char fname[FILENAME_MAX];
+	size_t fname_len;
+	struct stat stat_buf;
+	int udp_sock = socket(AF_INET, SOCK_DGRAM, 0);
+	if (udp_sock < 0) {
+		perror("Failed to initialize UDP socket");
+		exit(errno);
+	}
+	int sock_option = 1;
+	if (setsockopt(udp_sock, SOL_SOCKET, SO_BROADCAST, &sock_option, sizeof(sock_option)) < 0) {
+		perror("Failed to set UDP socket options");
+		exit(errno);
+	}
+	struct sockaddr_in broadcast_addr, server_addr;
+	socklen_t addr_len = sizeof(server_addr);
+	bzero(&broadcast_addr, sizeof(broadcast_addr));
+	broadcast_addr.sin_family = AF_INET;
+	broadcast_addr.sin_addr.s_addr = INADDR_BROADCAST;
+	broadcast_addr.sin_port = htons(PORT_UDP);
+	server_addr.sin_family = AF_INET;
+	server_addr.sin_addr.s_addr = INADDR_ANY;
+	server_addr.sin_port = htons(PORT_TCP);
+	int tcp_sock = socket(AF_INET, SOCK_STREAM, 0);
+	if (tcp_sock < 0) {
+		perror("Failed to initialize TCP socket");
+		exit(errno);
+	}
+	if (setsockopt(tcp_sock, SOL_SOCKET, SO_REUSEADDR, &sock_option, sizeof(sock_option)) < 0) {
+		perror("Failed to set TCP socket options");
+		exit(errno);
+	}
+	if (bind(tcp_sock, (struct sockaddr *) &server_addr, addr_len) < 0) {
+		perror("Failed to bind TCP socket");
+		exit(errno);
+	}
+	char buffer[BUF_SIZE];
+	printf("Searching server... ");
+	// send broadcast with the token
+	if (sendto(udp_sock, token, strlen(token), 0, (struct sockaddr *) &broadcast_addr, sizeof(broadcast_addr)) < strlen(token)) {
+		perror("Failed to broadcast request");
+		exit(errno);
+	}
+	// receive response from server
+	if (recvfrom(udp_sock, (void *) buffer, 2, 0, (struct sockaddr  *) &server_addr, &addr_len) < 2) {
+		perror("Failed to receive response");
+		exit(errno);
+	}
+	// check server response
+	printf("Server found, response: %.2s\n", buffer);
+	if (memcmp(buffer, "OK", 2) != 0) {
+		if (memcmp(buffer, "NO", 2) != 0) {
+			printf("Error: Got unexpected response from server\n");
+		} else {
+			printf("Request was rejected by server\n");
+		}
+		exit(1);
+	}
+	// connect to server
+	server_addr.sin_port = htons(PORT_TCP);
+	if (connect(tcp_sock, (struct sockaddr *) &server_addr, addr_len) < 0) {
+		perror("Failed to connect to server");
+		exit(errno);
+	}
+	printf("Getting file...\n");
+	// get file name
+	ssize_t rcount;
+	if ((rcount = read(tcp_sock, buffer, BUF_SIZE)) <= 0) {
+		perror("Failed to get file name");
+		exit(errno);
+	}
+	fname_len = strlen(buffer) + 1;
+	strcpy(fname, buffer);
+	// if path is a directory, append file name to it
+	if (stat(abspath, &stat_buf) == 0 && S_ISDIR(stat_buf.st_mode)) {
+		abspath[abspath_len - 1] = '/';
+		abspath[abspath_len] = 0;
+		strcat(abspath, fname);
+	}
+	FILE *file = fopen(abspath, "wb");
+	if (file == NULL) {
+		perror("Failed to open file");
+		exit(errno);
+	}
+	if (rcount > fname_len) {
+		fwrite(buffer + fname_len, 1, rcount - fname_len, file);
+	}
+	// get file data
+	for (;;) {
+		rcount = read(tcp_sock, buffer, BUF_SIZE);
+		if (rcount == 0) {
+			break;
+		}
+		if (rcount < 0) {
+			perror("Failed to get file");
+			exit(errno);
+		}
+		fwrite(buffer, 1, rcount, file);
+	}
+	fclose(file);
+	printf("Success!\nFile path: %s\n", realpath(abspath, abspath));
+}
+
+int main(int argc, char **argv) {
+	if (argc == 1) {
+		printf("Use '-h' to view help.\n");
+		return 0;
+	}
+	char *path = NULL,
+		 *token = NULL;
+	int mode_share;
+	int opt;
+	while ((opt = getopt(argc, argv, "hs:g:o:V")) != -1) {
+		switch (opt) {
+			case 'h':
+				printf(
+					"(C) Masahiko AMANO aka H1K0, 2024—present\n"
+					"(https://github.com/H1K0/aiken)\n\n"
+					"Usage:\n"
+					"  aiken <options> [arguments]\n\n"
+					"Options:\n"
+					"  -h           Print this help and exit\n"
+					"  -s <path>    Share the file of the specified <path>\n"
+					"  -g <token>   Get the file by its token\n"
+					"  -o <path>    Specify output path when getting file\n"
+					"               (defaults to current working directory and\n"
+					"               the initial file name)\n"
+					"  -V           Print version info and exit\n"
+				);
+				return 0;
+			case 'V':
+				printf("Aiken 0.1\n");
+				return 0;
+			case 's':
+				mode_share = 1;
+				path = realpath(optarg, path);
+				if (path == NULL) {
+					perror("Invalid share path");
+					return errno;
+				}
+				break;
+			case 'g':
+				mode_share = 0;
+				token = optarg;
+				break;
+			case 'o':
+				if (mode_share) {
+					fprintf(stderr, "Warning: The option '-o' is ignored when sharing.\n");
+					break;
+				}
+				path = optarg;
+				break;
+		}
+	}
+	if (mode_share) {
+		share(path);
+	} else {
+		get(token, path);
+	}
+	return 0;
+}