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version 1.2

/*************************************************************************
* (C) 2014 AITNET ltd - Sofia/Bulgaria - <misho@aitnet.org>
*  by Michael Pounov <misho@elwix.org>
*
* $Author: misho $
* $Id: tftpd.c,v 1.4 2014/02/24 22:28:54 misho Exp $
*
**************************************************************************
The ELWIX and AITNET software is distributed under the following
terms:

All of the documentation and software included in the ELWIX and AITNET
Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>

Copyright 2004 - 2014
	by Michael Pounov <misho@elwix.org>.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software
   must display the following acknowledgement:
This product includes software developed by Michael Pounov <misho@elwix.org>
ELWIX - Embedded LightWeight unIX and its contributors.
4. Neither the name of AITNET nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
*/
#include "global.h"
#include "srv.h"
#include "buf.h"
#include "exec.h"


intptr_t Kill;
struct tagCli cli;
cfg_root_t cfg;
sched_root_task_t *root;
rpack_t *bf;
char RW, szCfgName[PATH_MAX] = DEFAULT_CFGNAME;
struct timespec timeout = { DEFAULT_TIMEOUT, 0 };
extern char compiled[], compiledby[], compilehost[];

const struct tagErr errs[9] = {
	{ 0, "Not defined" }, 
	{ 1, "File not found" }, 
	{ 2, "Access violation" }, 
	{ 3, "Disk full or allocation exceeded" }, 
	{ 4, "Illegal TFTP operation" }, 
	{ 5, "Unknown transfer ID" }, 
	{ 6, "File already exists" }, 
	{ 7, "No such user" }, 
	{ 8, "Option not supported" }, 
};

static void
Usage()
{
	printf(	" -= TFTPd =- ELWIX extended TFTP service\n"
		"=== %s === %s@%s ===\n\n"
		" Syntax: TFTPd [options]\n\n"
		"\t-c <config>\tConfig file [default=/etc/tftpd.conf]\n"
		"\t-w\t\tSwitch to read-write mode [default=read-only]\n"
		"\t-b\t\tRun into batch mode (default is daemon mode)\n"
		"\t-R\t\tReboot after complete write file\n"
		"\t-d\t\tDebug program\n"
		"\t-v\t\tVerbose (more -v, more verbosity ...)\n"
		"\t-h\t\tThis help screen!\n"
		"\n", compiled, compiledby, compilehost);
}

static void *
sigHandler(sched_task_t *task)
{
	int stat;
	const char *str;

	switch (TASK_VAL(task)) {
		case SIGHUP:
			cfgUnloadConfig(&cfg);
			if (cfgLoadConfig(szCfgName, &cfg)) {
				ELIBERR(cfg);
				Kill++;
			} else
				EVERBOSE(1, "Reloading config ...");

			str = cfg_getAttribute(&cfg, "tftpd", "timeout");
			if (str)
				timeout.tv_sec = strtol(str, NULL, 10);

			endBuffer();
			str = cfg_getAttribute(&cfg, "tftpd", "buf_io");
			if (str)
				initBuffer(strtol(str, NULL, 0));
			break;
		case SIGINT:
		case SIGTERM:
			EVERBOSE(1, "Terminate service ...");
			Kill++;
			break;
		case SIGCHLD:
			while (waitpid(-1, &stat, WNOHANG) > 0);
			break;
		default:
			EERROR(EINVAL, "Unknown signal #%lu?", TASK_VAL(task));
			break;
	}

	schedSignalSelf(task);
	taskExit(task, NULL);
}

int
main(int argc, char **argv)
{
	char ch, r = 0, b = 0;
	const char *str;
	int fd, uid = 0, ret = 0;
	struct passwd *pass;
	pid_t pid;
	sockaddr_t sa;
	rpack_t *pkt = NULL;

	while ((ch = getopt(argc, argv, "hvdRbwc:")) != -1)
		switch (ch) {
			case 'c':
				strlcpy(szCfgName, optarg, sizeof szCfgName);
				break;
			case 'w':
				RW = 42;	/* rw mode */
				break;
			case 'v':
				e_incVerbose;
				break;
			case 'd':
				elwix_Debug |= ELWIX_DEBUG_TRACE;
				break;
			case 'b':
				b = 42;
				break;
			case 'R':
				r = 42;
				break;
			case 'h':
			default:
				Usage();
				return 1;
		}
	argc -= optind;
	argv += optind;

	openlog("TFTPd", LOG_PID | LOG_CONS, LOG_FTP);
	if (cfgLoadConfig(szCfgName, &cfg)) {
		ELIBERR(cfg);
		return 2;
	}

	str = cfg_getAttribute(&cfg, "tftpd", "user");
	if (str) {
		pass = getpwnam(str);
		if (!pass) {
			EERROR(EINVAL, "User %s not found!\n", str);
			ret = 2;
			goto end;
		} else
			uid = pass->pw_uid;
		endpwent();
	}

	if (!b)	/* service mode */
		switch ((pid = fork())) {
			case -1:
				ret = 3;
				goto end;
			case 0:
				setsid();
				chdir("/");

				fd = open(_PATH_DEVNULL, O_RDWR);
				if (fd > 2) {
					dup2(fd, STDIN_FILENO);
					dup2(fd, STDOUT_FILENO);
					dup2(fd, STDERR_FILENO);
					close(fd);
				}
				EVERBOSE(1, "Welcome to the shadow-land!\n");
				break;
			default:
				EVERBOSE(1, "Starting service with pid=%d ...\n", pid);
				goto end;
		}

	root = schedBegin();
	if (!root) {
		ELIBERR(sched);
		ret = 3;
		goto end;
	}

	str = cfg_getAttribute(&cfg, "tftpd", "timeout");
	if (str)
		timeout.tv_sec = strtol(str, NULL, 10);

	str = cfg_getAttribute(&cfg, "tftpd", "port");
	if (str)
		fd = strtol(str, NULL, 10);
	else
		fd = 69;
	str = cfg_getAttribute(&cfg, "tftpd", "bind");
	e_gethostbyname(str ? str : "0.0.0.0", fd, &sa);
	fd = socket(sa.sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
	if (fd == -1) {
		ESYSERR(0);
		ret = 4;
		goto end;
	}
	if (bind(fd, &sa.sa, sa.sa.sa_len) == -1) {
		ESYSERR(0);
		close(fd);
		ret = 4;
		goto end;
	}

	str = cfg_getAttribute(&cfg, "tftpd", "chroot");
	if (str && chroot(str) == -1) {
		ESYSERR(0);
		close(fd);
		ret = 3;
		goto end;
	} else {
		setuid(uid);
		str = cfg_getAttribute(&cfg, "tftpd", "dir");
		if (str)
			chdir(str);
	}

	str = cfg_getAttribute(&cfg, "tftpd", "buf_io");
	if (str)
		initBuffer(strtol(str, NULL, 0));

	if (!(pkt = rpack_create(NULL, 0))) {
		ELIBERR(elwix);
		close(fd);
		ret = 5;
		goto end;
	}
	if (rpack_attach(pkt, TFTP_PKT_MAX)) {
		ELIBERR(elwix);
		close(fd);
		ret = 5;
		goto end;
	}

	memset(&cli, 0, sizeof cli);
	if (r)
		schedSuspend(root, Reboot, NULL, 0, NULL, 0);
	schedSignal(root, sigHandler, NULL, SIGHUP, NULL, 0);
	schedSignal(root, sigHandler, NULL, SIGTERM, NULL, 0);
	schedSignal(root, sigHandler, NULL, SIGINT, NULL, 0);
	schedSignal(root, sigHandler, NULL, SIGCHLD, NULL, 0);
	schedRead(root, rxPkt, NULL, fd, pkt, sizeof(rpack_t));
	schedRun(root, &Kill);

	close(fd);
end:
	schedEnd(&root);
	rpack_detach(pkt);
	rpack_destroy(&pkt);
	endBuffer();
	cfgUnloadConfig(&cfg);
	closelog();
	return ret;
}