tiny.c

#include <arpa/inet.h> /* inet_ntoa */
#include <signal.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <time.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sendfile.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#define LISTENQ  1024  /* second argument to listen() */
#define MAXLINE 1024   /* max length of a line */
#define RIO_BUFSIZE 1024

#ifndef DEFAULT_PORT
#define DEFAULT_PORT 9999 /* use this port if none given as arg to main() */
#endif

#ifndef FORK_COUNT
#define FORK_COUNT 4
#endif

#ifndef NO_LOG_ACCESS
#define LOG_ACCESS
#endif

typedef struct {
	int rio_fd;                 /* descriptor for this buf */
	int rio_cnt;                /* unread byte in this buf */
	char *rio_bufptr;           /* next unread byte in this buf */
	char rio_buf[RIO_BUFSIZE];  /* internal buffer */
} rio_t;

/* Simplifies calls to bind(), connect(), and accept() */
typedef struct sockaddr SA;

typedef struct {
	char filename[512];
	off_t offset;              /* for support Range */
	size_t end;
} http_request;

typedef struct {
	const char *extension;
	const char *mime_type;
} mime_map;

//https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types

mime_map meme_types [] = {
	{".aac",  "audio/aac"},
	{".abw",  "application/x-abiword"},
	{".arc",  "application/x-freearc"},
	{".avi",  "video/x-msvideo"},
	{".azw",  "application/vnd.amazon.ebook"},
	{".bin",  "application/octet-stream"},
	{".bmp",  "image/bmp"},
	{".bz",   "application/x-bzip"},
	{".bz2",  "application/x-bzip2"},
	{".csh",  "application/x-csh"},
	{".css",  "text/css"},
	{".csv",  "text/csv"},
	{".doc",  "application/msword"},
	{".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
	{".eot",  "application/vnd.ms-fontobject"},
	{".epub", "application/epub+zip"},
	{".gz",   "application/gzip"},
	{".gif",  "image/gif"},
	{".htm",  "text/html"},
	{".html", "text/html"},
	{".ico",  "image/vnd.microsoft.icon"},
	{".ics",  "text/calendar"},
	{".jar",  "application/java-archive"},
	{".jpeg", "image/jpeg"},
	{".jpg",  "image/jpeg"},
	{".js",   "text/javascript"},
	{".json",  "application/json"},
	{".jsonld", "application/ld+json"},
	{".mid",   "audio/midi audio/x-midi"},
	{".midi",  "audio/midi audio/x-midi"},
	{".mjs",   "text/javascript"},
	{".mp3",   "audio/mpeg"},
	{".mp4",   "video/mp4"},
	{".mpeg",  "video/mpeg"},
	{".mpkg",  "application/vnd.apple.installer+xml"},
	{".odp",   "application/vnd.oasis.opendocument.presentation"},
	{".ods",   "application/vnd.oasis.opendocument.spreadsheet"},
	{".odt",   "application/vnd.oasis.opendocument.text"},
	{".oga",   "audio/ogg"},
	{".ogv",   "video/ogg"},
	{".ogx",   "application/ogg"},
	{".opus",  "audio/opus"},
	{".otf",   "font/otf"},
	{".png",   "image/png"},
	{".pdf",   "application/pdf"},
	{".php",   "application/x-httpd-php"},
	{".ppt",   "application/vnd.ms-powerpoint"},
	{".pptx",  "application/vnd.openxmlformats-officedocument.presentationml.presentation"},
	{".rar",   "application/vnd.rar"},
	{".rtf",   "application/rtf"},
	{".sh",    "application/x-sh"},
	{".svg",   "image/svg+xml"},
	{".swf",   "application/x-shockwave-flash"},
	{".tar",   "application/x-tar"},
	{".tif",   "image/tiff"},
	{".tiff",  "image/tiff"},
	{".ts",    "video/mp2t"},
	{".ttf",   "font/ttf"},
	{".txt",   "text/plain"},
	{".vsd",   "application/vnd.visio"},
	{".wav",   "audio/wav"},
	{".weba",  "audio/webm"},
	{".webm",  "video/webm"},
	{".webp",  "image/webp"},
	{".woff",  "font/woff"},
	{".woff2", "font/woff2"},
	{".xhtml", "application/xhtml+xml"},
	{".xls",   "application/vnd.ms-excel"},
	{".xlsx",  "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
	{".xml",   "text/xml"},
	{".xul",   "application/vnd.mozilla.xul+xml"},
	{".zip",   "application/zip"},
	{".3gp",   "video/3gpp"},
	{".3g2",   "video/3gpp2"},
	{".7z",    "application/x-7z-compressed"},
	{NULL, NULL},
};

char *default_mime_type = "text/plain";

void rio_readinitb(rio_t *rp, int fd) {
	rp->rio_fd = fd;
	rp->rio_cnt = 0;
	rp->rio_bufptr = rp->rio_buf;
}

ssize_t writen(int fd, void *usrbuf, size_t n) {
	size_t nleft = n;
	ssize_t nwritten;
	char *bufp = usrbuf;

	while (nleft > 0) {
		if ((nwritten = write(fd, bufp, nleft)) <= 0) {
			if (errno == EINTR) {  /* interrupted by sig handler return */
				nwritten = 0;    /* and call write() again */
			}
			else{
				return -1;       /* errorno set by write() */
			}
		}
		nleft -= nwritten;
		bufp += nwritten;
	}
	return n;
}


/*
 * rio_read - This is a wrapper for the Unix read() function that
 *    transfers min(n, rio_cnt) bytes from an internal buffer to a user
 *    buffer, where n is the number of bytes requested by the user and
 *    rio_cnt is the number of unread bytes in the internal buffer. On
 *    entry, rio_read() refills the internal buffer via a call to
 *    read() if the internal buffer is empty.
 */
/* $begin rio_read */
static ssize_t rio_read(rio_t *rp, char *usrbuf, size_t n) {
	int cnt;
	while (rp->rio_cnt <= 0) {  /* refill if buf is empty */

		rp->rio_cnt = read(rp->rio_fd, rp->rio_buf,
						   sizeof(rp->rio_buf));
		if (rp->rio_cnt < 0) {
			if (errno != EINTR) { /* interrupted by sig handler return */
				return -1;
			}
		}
		else if (rp->rio_cnt == 0) {  /* EOF */
			return 0;
		}
		else
			rp->rio_bufptr = rp->rio_buf; /* reset buffer ptr */
	}

	/* Copy min(n, rp->rio_cnt) bytes from internal buf to user buf */
	cnt = n;
	if (rp->rio_cnt < n) {
		cnt = rp->rio_cnt;
	}
	memcpy(usrbuf, rp->rio_bufptr, cnt);
	rp->rio_bufptr += cnt;
	rp->rio_cnt -= cnt;
	return cnt;
}

/*
 * rio_readlineb - robustly read a text line (buffered)
 */
ssize_t rio_readlineb(rio_t *rp, void *usrbuf, size_t maxlen) {
	int n, rc;
	char c, *bufp = usrbuf;

	for (n = 1; n < maxlen; n++) {
		if ((rc = rio_read(rp, &c, 1)) == 1) {
			*bufp++ = c;
			if (c == '\n') {
				break;
			}
		} else if (rc == 0) {
			if (n == 1) {
				return 0; /* EOF, no data read */
			}
			else{
				break;    /* EOF, some data was read */
			}
		} else{
			return -1;    /* error */
		}
	}
	*bufp = 0;
	return n;
}

void format_size(char* buf, struct stat *stat) {
	if(S_ISDIR(stat->st_mode)) {
		sprintf(buf, "%s", "[DIR]");
	} else {
		off_t size = stat->st_size;
		if(size < 1024) {
			sprintf(buf, "%lu", size);
		} else if (size < 1024 * 1024) {
			sprintf(buf, "%.1fK", (double)size / 1024);
		} else if (size < 1024 * 1024 * 1024) {
			sprintf(buf, "%.1fM", (double)size / 1024 / 1024);
		} else {
			sprintf(buf, "%.1fG", (double)size / 1024 / 1024 / 1024);
		}
	}
}

void handle_directory_request(int out_fd, int dir_fd, char *filename) {
	char buf[MAXLINE], m_time[32], size[16];
	struct stat statbuf;
	sprintf(buf, "HTTP/1.1 200 OK\r\n%s%s%s%s%s",
			"Content-Type: text/html\r\n\r\n",
			"<html><head><style>",
			"body{font-family: monospace; font-size: 13px;}",
			"td {padding: 1.5px 6px;}",
			"</style></head><body><table>\n");
	writen(out_fd, buf, strlen(buf));
	DIR *d = fdopendir(dir_fd);
	struct dirent *dp;
	int ffd;
	while ((dp = readdir(d)) != NULL) {
		if(!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")) {
			continue;
		}
		if ((ffd = openat(dir_fd, dp->d_name, O_RDONLY)) == -1) {
			perror(dp->d_name);
			continue;
		}
		fstat(ffd, &statbuf);
		strftime(m_time, sizeof(m_time),
				 "%Y-%m-%d %H:%M", localtime(&statbuf.st_mtime));
		format_size(size, &statbuf);
		if(S_ISREG(statbuf.st_mode) || S_ISDIR(statbuf.st_mode)) {
			char *d = S_ISDIR(statbuf.st_mode) ? "/" : "";
			sprintf(buf, "<tr><td><a href=\"%s%s\">%s%s</a></td><td>%s</td><td>%s</td></tr>\n",
					dp->d_name, d, dp->d_name, d, m_time, size);
			writen(out_fd, buf, strlen(buf));
		}
		close(ffd);
	}
	sprintf(buf, "</table></body></html>");
	writen(out_fd, buf, strlen(buf));
	closedir(d);
}

static const char* get_mime_type(char *filename) {
	char *dot = strrchr(filename, '.');
	if(dot) { // strrchar Locate last occurrence of character in string
		mime_map *map = meme_types;
		while(map->extension) {
			if(strcmp(map->extension, dot) == 0) {
				return map->mime_type;
			}
			map++;
		}
	}
	return default_mime_type;
}


int open_listenfd(int port) {
	int listenfd, optval=1;
	struct sockaddr_in serveraddr;

	/* Create a socket descriptor */
	if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
		return -1;
	}

	/* Eliminates "Address already in use" error from bind. */
	if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR,
				   (const void *)&optval , sizeof(int)) < 0) {
		return -1;
	}

	// 6 is TCP's protocol number
	// enable this, much faster : 4000 req/s -> 17000 req/s
	if (setsockopt(listenfd, 6, TCP_CORK,
				   (const void *)&optval , sizeof(int)) < 0) {
		return -1;
	}

	/* Listenfd will be an endpoint for all requests to port
	   on any IP address for this host */
	memset(&serveraddr, 0, sizeof(serveraddr));
	serveraddr.sin_family = AF_INET;
	serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
	serveraddr.sin_port = htons((unsigned short)port);
	if (bind(listenfd, (SA *)&serveraddr, sizeof(serveraddr)) < 0) {
		return -1;
	}

	/* Make it a listening socket ready to accept connection requests */
	if (listen(listenfd, LISTENQ) < 0) {
		return -1;
	}
	return listenfd;
}

void url_decode(char* src, char* dest, int max) {
	char *p = src;
	char code[3] = { 0 };
	while(*p && --max) {
		if(*p == '%') {
			memcpy(code, ++p, 2);
			*dest++ = (char)strtoul(code, NULL, 16);
			p += 2;
		} else {
			*dest++ = *p++;
		}
	}
	*dest = '\0';
}

void parse_request(int fd, http_request *req) {
	rio_t rio;
	char buf[MAXLINE], method[MAXLINE], uri[MAXLINE];
	req->offset = 0;
	req->end = 0;			  /* default */

	rio_readinitb(&rio, fd);
	rio_readlineb(&rio, buf, MAXLINE);
	sscanf(buf, "%s %s", method, uri); /* version is not cared */
	/* read all */
	while(buf[0] != '\n' && buf[1] != '\n') { /* \n || \r\n */
		rio_readlineb(&rio, buf, MAXLINE);
		if(buf[0] == 'R' && buf[1] == 'a' && buf[2] == 'n') {
			sscanf(buf, "Range: bytes=%lu-%lu", &req->offset, &req->end);
			// Range: [start, end]
			if( req->end != 0) {req->end ++;}
		}
	}
	char* filename = uri;
	if(uri[0] == '/') {
		filename = uri + 1;
		int length = strlen(filename);
		if (length == 0) {
			filename = ".";
		} else {
			int i=0;
			for (; i < length; ++ i) {
				if (filename[i] == '?') {
					filename[i] = '\0';
					break;
				}
			}
		}
	}
	url_decode(filename, req->filename, MAXLINE);
}

#ifdef LOG_ACCESS
void log_access(int status, struct sockaddr_in *c_addr, http_request *req) {
	printf("%s:%d %d - '%s' (%s)\n", inet_ntoa(c_addr->sin_addr),
		   ntohs(c_addr->sin_port), status, req->filename, get_mime_type(req->filename));
}
#endif

void client_error(int fd, int status, char *msg, char *longmsg) {
	char buf[MAXLINE];
	sprintf(buf, "HTTP/1.1 %d %s\r\n", status, msg);
	sprintf(buf + strlen(buf),
			"Content-length: %lu\r\n\r\n", strlen(longmsg));
	sprintf(buf + strlen(buf), "%s", longmsg);
	writen(fd, buf, strlen(buf));
}

void serve_static(int out_fd, int in_fd, http_request *req,
				  size_t total_size) {
	char buf[256];
	if (req->offset > 0) {
		sprintf(buf, "HTTP/1.1 206 Partial\r\n");
		sprintf(buf + strlen(buf), "Content-Range: bytes %lu-%lu/%lu\r\n",
				req->offset, req->end, total_size);
	} else {
		sprintf(buf, "HTTP/1.1 200 OK\r\nAccept-Ranges: bytes\r\n");
	}
	sprintf(buf + strlen(buf), "Cache-Control: no-cache\r\n");
	// sprintf(buf + strlen(buf), "Cache-Control: public, max-age=315360000\r\nExpires: Thu, 31 Dec 2037 23:55:55 GMT\r\n");

	sprintf(buf + strlen(buf), "Content-length: %lu\r\n",
			req->end - req->offset);
	sprintf(buf + strlen(buf), "Content-type: %s\r\n\r\n",
			get_mime_type(req->filename));

	writen(out_fd, buf, strlen(buf));
	off_t offset = req->offset; /* copy */
	while(offset < req->end) {
		if(sendfile(out_fd, in_fd, &offset, req->end - req->offset) <= 0) {
			break;
		}
#ifdef LOG_ACCESS
		printf("offset: %d \n\n", (unsigned int)offset);
#endif
		close(out_fd);
		break;
	}
}

void process(int fd, struct sockaddr_in *clientaddr) {
#ifdef LOG_ACCESS
	printf("accept request, fd is %d, pid is %d\n", fd, getpid());
#endif
	http_request req;
	parse_request(fd, &req);

	struct stat sbuf;
	int status = 200, ffd = open(req.filename, O_RDONLY, 0);
	if(ffd <= 0) {
		status = 404;
		char *msg = "File not found";
		client_error(fd, status, "Not found", msg);
	} else {
		fstat(ffd, &sbuf);
		if(S_ISREG(sbuf.st_mode)) {
			if (req.end == 0) {
				req.end = sbuf.st_size;
			}
			if (req.offset > 0) {
				status = 206;
			}
			serve_static(fd, ffd, &req, sbuf.st_size);
		} else if(S_ISDIR(sbuf.st_mode)) {
			status = 200;
			handle_directory_request(fd, ffd, req.filename);
		} else {
			status = 400;
			char *msg = "Unknow Error";
			client_error(fd, status, "Error", msg);
		}
		close(ffd);
	}
#ifdef LOG_ACCESS
	log_access(status, clientaddr, &req);
#endif
}

void print_help()
{
	printf("TINY WEBSERVER HELP\n");
	printf("tiny            #use default port, serve current dir\n");
	printf("tiny /tmp       #use default port, serve given dir\n");
	printf("tiny 1234       #use given port, serve current dir\n");
	printf("tiny /tmp 1234  #use given port, serve given dir\n");
	printf("default port is %d.\n", DEFAULT_PORT);
}

int main(int argc, char** argv) {

	if(argc > 1 && (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")))
	{
		print_help();
		return 0;
	}

	struct sockaddr_in clientaddr;
	int default_port = DEFAULT_PORT,
		listenfd,
		connfd;
	char buf[256];
	char *path = getcwd(buf, 256);
	socklen_t clientlen = sizeof clientaddr;
	if(argc == 2) {
		if(argv[1][0] >= '0' && argv[1][0] <= '9') {
			default_port = atoi(argv[1]);
		} else {
			path = argv[1];
			if(chdir(path) != 0) {
				perror(path);
				exit(1);
			}
		}
	} else if (argc == 3) {
		default_port = atoi(argv[2]);
		path = argv[1];
		if(chdir(path) != 0) {
			perror(path);
			exit(1);
		}
	}
	printf("serve directory '%s'\n", path);

	listenfd = open_listenfd(default_port);
	if (listenfd > 0) {
		printf("listen on port %d, fd is %d\n", default_port, listenfd);
	} else {
		perror("ERROR");
		exit(listenfd);
	}
	// Ignore SIGPIPE signal, so if browser cancels the request, it
	// won't kill the whole process.
	signal(SIGPIPE, SIG_IGN);

	int i=0;
	for(; i < FORK_COUNT; i++) {
		int pid = fork();
		if (pid == 0) {		 //  child
			while(1) {
				connfd = accept(listenfd, (SA *)&clientaddr, &clientlen);
				process(connfd, &clientaddr);
				close(connfd);
			}
		} else if (pid > 0) {   //  parent
			printf("child pid is %d\n", pid);
		} else {
			perror("fork");
		}
	}

	while(1) {
		connfd = accept(listenfd, (SA *)&clientaddr, &clientlen);
		process(connfd, &clientaddr);
		close(connfd);
	}

	return 0;
}