sws_q7.cpp

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sys/sendfile.h>
#include <sys/stat.h>
#include <sys/timerfd.h>
#include <sys/epoll.h>
#include <signal.h>
#include <map>
#include <ctime>

#include "utility.h"
#include "inet_socket.h"

#define BUF_SIZE 300
#define LISTEN_PORT "8080"
#define BACKLOG 5
#define EPOLL_SIZE 10
#define MAX_EVENTS 10

using std::map;

int main(int argc, char *argv[])
{
	if (argc < 2) {
		errExit("invalid number of arguments");
		return EXIT_FAILURE;
	}

	int listen_fd = inetListen(LISTEN_PORT, BACKLOG, NULL);
	if (listen_fd == -1)
		errExit("inetListen");

	signal(SIGPIPE, SIG_IGN);

	// Turn on non-blocking mode on the passive socket
	int flags = fcntl(listen_fd, F_GETFL);

	if (fcntl(listen_fd, F_SETFL, flags | O_NONBLOCK) == -1)
		errExit("listen fd non block");

	// Initialize the epoll instance
	int epfd;
	epfd = epoll_create(EPOLL_SIZE);

	if (epfd == -1)
		errExit("epoll_create");

	struct epoll_event ev;
	ev.events = EPOLLIN; // event : data can be read

	// add listen_fd to the interest list
	ev.data = {};
	ev.data.fd = listen_fd;

	if (epoll_ctl(epfd, EPOLL_CTL_ADD, listen_fd, &ev) == -1)
		errExit("epoll_ctl");

	// the event list used with epoll_wait()
	struct epoll_event evlist[MAX_EVENTS];
	map<int, int> connections;
	for (;; ) {
		int nb_fd_ready = epoll_wait(epfd, evlist, MAX_EVENTS, 0);
		if (nb_fd_ready == -1) {
			if (errno == EINTR) // restart if interrupted by signal
				continue;
			else
				errExit("epoll");
		}

		for (int i = 0; i < nb_fd_ready; ++i) {
			int fd_ready = evlist[i].data.fd;
			if (fd_ready == listen_fd) {
				int client_fd = accept(listen_fd, NULL, NULL);
				printf("Accept a new connection... \n");
				int timerfd = timerfd_create(CLOCK_REALTIME, 0);
				if (epoll_ctl(epfd, EPOLL_CTL_ADD, timerfd, &ev) == -1)
					errExit("epoll_ctl");
				connections[timerfd] = client_fd;
				struct itimerspec timerspec = {};
				timerspec.it_value.tv_sec = 5;
				timerfd_settime(timerfd, 0, &timerspec, NULL);
				flags = fcntl(client_fd, F_GETFL);

				if (fcntl(client_fd, F_SETFL, flags | O_NONBLOCK) == -1) {
					close(client_fd);
					printf("Closed connection...\n");
				} else {
					ev.data.fd = client_fd;
					if (epoll_ctl(epfd, EPOLL_CTL_ADD, client_fd, &ev) == -1) {
						close(client_fd);
						printf("Closed connection...\n");
					}
				}
			} else if (connections.count(fd_ready) == 1) {
				close(connections[fd_ready]);
				printf("Closed connection because of timeout...\n");
				if (epoll_ctl(epfd, EPOLL_CTL_DEL, fd_ready, &ev) == -1)
					errExit("epoll_ctl");
			} else {
				char buf[BUF_SIZE];
				int numRead = read(fd_ready, buf, BUF_SIZE);

				if (numRead == 0) {
					close(fd_ready);
					printf("Closed connection...\n");
				}

				if (write(STDOUT_FILENO, buf, numRead) != numRead)
					errExit("partial/failed write");

				char *request = strtok(buf, " ");
				request = strtok(NULL, " ");
				char path[BUF_SIZE];
				snprintf(path, BUF_SIZE, "%s%s", argv[1], request);
				struct stat sb;

				if (stat(path, &sb) == 0 && S_ISDIR(sb.st_mode)) {
					char path2[BUF_SIZE];
					strcpy(path2, path);
					snprintf(path, BUF_SIZE, "%sindex.html", path2);
					printf("PATH = %s\n", path);
				}

				int fd = open(path, O_RDONLY);

				if (fd < 0) {
					char headers[BUF_SIZE];
					ssize_t nbBytes = snprintf(headers, BUF_SIZE, "HTTP/1.x 404 NOT FOUND\r\nConnection: keep-alive\r\n\r\n");
					write(fd_ready, headers, nbBytes);
				} else {
					struct stat stat_buf;
					fstat(fd, &stat_buf);
					char headers[BUF_SIZE];
					ssize_t nbBytes = snprintf(headers, BUF_SIZE, "HTTP/1.x 200 OK\r\nContent-Type: text/html;\r\nContent-Length: %i\r\ncharset=UTF-8\r\nConnection: keep-alive\r\n\r\n", stat_buf.st_size);
					write(fd_ready, headers, nbBytes);
					sendfile(fd_ready, fd, 0, stat_buf.st_size);
					close(fd);
				}
			}
		}
	}
	close(listen_fd);
	return EXIT_SUCCESS;
}