diff -r 000000000000 -r 9d0a04089d22 test/tftpd.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/tftpd.c	Mon Jul 11 16:49:53 2016 +0100
@@ -0,0 +1,231 @@
+/*
+ * Copyright (C) 2016  J. Ali Harlow <ali@juiblex.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <arpa/tftp.h>
+
+/*
+ * A simple TFTP server suitable only for use on the loopback interface
+ * (it has no support for retransmitting lost packets).
+ */
+
+char inbuf[SEGSIZE+4];
+char outbuf[SEGSIZE+4];
+
+int send_error(int s, const struct sockaddr *client, socklen_t client_addr_len,
+	       unsigned short code,const char *message)
+{
+	int r;
+	char *buf;
+	size_t len;
+
+	len = 4 + strlen(message) + 1;
+	buf = malloc(len);
+	((unsigned short *)buf)[0] = htons(ERROR);
+	((unsigned short *)buf)[1] = htons(code);
+	strcpy(buf + 4, message);
+	r = sendto(s, buf, len, 0, client, client_addr_len);
+	free(buf);
+
+	return r;
+}
+
+int send_file(int s, const struct sockaddr *client, socklen_t client_addr_len,
+	       const char *path, const char *mode)
+{
+	const char *dotdot, *p;
+	FILE *fp;
+	size_t nb;
+	int block = 0;
+
+	if (strcasecmp(mode, "octet")) {
+		send_error(s, client, client_addr_len, EBADOP, "Bad mode");
+		return -1;
+	}
+
+	if (!*path || *path == '/') {
+		send_error(s, client, client_addr_len, EACCESS,
+			   "Access denied");
+		return -1;
+	}
+
+	for (p = path; *p;) {
+		dotdot = strstr(p, "..");
+		if (!dotdot)
+			break;
+		if ((dotdot == path || dotdot[-1] == '/') &&
+		    (dotdot[2] == '/' || dotdot[2] == '\0')) {
+			send_error(s, client, client_addr_len, EACCESS,
+				   "Access denied");
+			return -1;
+		}
+		p = dotdot + 2;
+	}
+
+	fp = fopen(path, "rb");
+
+	if (!fp) {
+		if (errno == ENOENT)
+			send_error(s, client, client_addr_len, ENOTFOUND,
+				   strerror(errno));
+		else if (errno == EACCES)
+			send_error(s, client, client_addr_len, EACCESS,
+				   strerror(errno));
+		else
+			send_error(s, client, client_addr_len, EUNDEF,
+				   strerror(errno));
+		return -1;
+	}
+
+	((unsigned short *)outbuf)[0] = htons(DATA);
+
+	while((nb = fread(outbuf + 4, 1, SEGSIZE, fp)) >= 0)
+	{
+		((unsigned short *)outbuf)[1] = htons(++block);
+		if (sendto(s, outbuf, nb + 4, 0, client, client_addr_len) < 0) {
+			perror("sendto");
+			fclose(fp);
+			return -1;
+		}
+
+		/* Discard ACKs */
+		(void)recvfrom(s, inbuf, sizeof(inbuf), 0, NULL, NULL);
+		
+		if (nb < SEGSIZE)
+			break;
+	}
+
+	fclose(fp);
+
+	return 0;
+}
+
+void serve(int s)
+{
+	char *filename, *mode;
+	struct sockaddr_storage client;
+	socklen_t client_addr_len;
+	ssize_t nb;
+
+	for(;;) {
+		client_addr_len = sizeof(client);
+		nb = recvfrom(s, inbuf, sizeof(inbuf), 0,
+			      (struct sockaddr *)&client, &client_addr_len);
+
+		if (nb < 0) {
+			perror("recvfrom");
+			exit(1);
+		}
+
+		if (nb >= 2) {
+			switch (ntohs(*(unsigned short *)inbuf)) {
+			case RRQ:
+				filename = inbuf + 2;
+				mode = memchr(filename, '\0', nb - 2);
+				if (!mode) {
+					send_error(s,
+						   (struct sockaddr *)&client,
+						   client_addr_len, EBADOP,
+						   "Bad request");
+					break;
+				}
+				mode++;
+				if (!memchr(mode, '\0', nb - (mode - inbuf))) {
+					send_error(s,
+						   (struct sockaddr *)&client,
+						   client_addr_len, EBADOP,
+						   "Bad request");
+					break;
+				}
+				send_file(s, (struct sockaddr *)&client,
+					  client_addr_len, filename, mode);
+				break;
+			case WRQ:
+				send_error(s, (struct sockaddr *)&client,
+					   client_addr_len, EACCESS,
+					   "Access denied");
+				break;
+			case DATA:
+			case ACK:
+			case ERROR:
+				break;
+			}
+		}
+	}
+}
+
+main(int argc, char **argv)
+{
+	int s;
+	pid_t pid;
+	FILE *fp;
+	in_port_t port;
+	struct sockaddr_in sin = {0,};
+
+	s = socket(AF_INET, SOCK_DGRAM, 0);
+	if (s < 0) {
+		perror("socket");
+		exit(1);
+	}
+
+	sin.sin_family = AF_INET;
+	sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+
+	for (port = 0;; port++) {
+		sin.sin_port = htons(IPPORT_USERRESERVED + port);
+		if (!bind(s, (struct sockaddr *)&sin, sizeof(sin)))
+			break;
+		if (errno != EADDRINUSE || port >= 1023) {
+			perror("bind");
+			exit(1);
+		}
+	}
+
+	if (argc > 2) {
+		fp = fopen(argv[2], "w");
+		if (fp) {
+			fprintf(fp, "%ld\n", (long)ntohs(sin.sin_port));
+			fclose(fp);
+		}
+
+		pid = fork();
+		if (pid) {
+			fp = fopen(argv[1], "w");
+			if (fp) {
+				fprintf(fp, "%ld\n", (long)pid);
+				fclose(fp);
+			}
+			exit(0);
+		}
+	} else
+		printf("%d\n", ntohs(sin.sin_port));
+
+	serve(s);
+
+	exit(0);
+}