path: root/tinyNET/src/dns/tnet_dns_resolvconf.c

/* #line 1 "./ragel/tnet_dns_resolvconf.rl" */
/*
* Copyright (C) 2010-2015 Mamadou DIOP.
*
* This file is part of Open Source Doubango Framework.
*
* DOUBANGO 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 3 of the License, or
* (at your option) any later version.
*	
* DOUBANGO 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 DOUBANGO.
*
*/
/**@file tnet_dns_resolvconf.c
 * @brief Parser for "/etc/resolv.conf" file to retrive DNS servers.
 */
#include "tnet_dns_resolvconf.h"

#include "tnet_utils.h"

#include "dns/tnet_dns.h"

#include "tsk_string.h"
#include "tsk_memory.h"
#include "tsk_ragel_state.h"
#include "tsk_debug.h"

#include <string.h>


/* ===	Ragel state machine === */

/* #line 75 "./ragel/tnet_dns_resolvconf.rl" */


/** Gets list of DNS servers from a conf file.
* @param path Path of the conf file from which to retrieve the DNS servers.
* should be @a "/etc/resolv.conf". You can adjust the value by modifying @ref TNET_RESOLV_CONF_PATH.<br>
* If you are using <b>Android</b> and the resolv.conf file is missing, then run the following line in a command window: <br>
* <i>ln -s /private/var/run/resolv.conf /etc/resolv.conf</i><br> If this fails, then try to manually add the file.
* @retval List of DNS servers.
*/
tnet_addresses_L_t * tnet_dns_resolvconf_parse(const char* path)
{
	tnet_addresses_L_t* servers = tsk_null;
	tnet_ip_t ip;
	const char* fullpath = path;
	const char* tag_start = tsk_null;
	FILE* fd;
	char* buf = tsk_null;
	
	// Ragel
	int cs = 0;
	const char *p;
	const char *pe;
	const char *eof;

	TSK_RAGEL_DISABLE_WARNINGS_BEGIN()
	
/* #line 69 "./src/dns/tnet_dns_resolvconf.c" */
static const char _tdns_machine_resolvconf_actions[] = {
	0, 1, 0, 1, 1
};

static const char _tdns_machine_resolvconf_key_offsets[] = {
	0, 7, 8, 9, 12, 15, 15, 22, 
	24, 27, 30, 33, 36, 39, 42, 45, 
	48, 51, 52, 53, 56
};

static const char _tdns_machine_resolvconf_trans_keys[] = {
	10, 13, 32, 35, 59, 78, 110, 32, 
	32, 10, 13, 32, 10, 13, 32, 10, 
	13, 32, 35, 59, 78, 110, 10, 13, 
	32, 65, 97, 32, 77, 109, 32, 69, 
	101, 32, 83, 115, 32, 69, 101, 32, 
	82, 114, 32, 86, 118, 32, 69, 101, 
	32, 82, 114, 32, 32, 10, 13, 32, 
	32, 35, 59, 78, 110, 0
};

static const char _tdns_machine_resolvconf_single_lengths[] = {
	7, 1, 1, 3, 3, 0, 7, 2, 
	3, 3, 3, 3, 3, 3, 3, 3, 
	3, 1, 1, 3, 5
};

static const char _tdns_machine_resolvconf_range_lengths[] = {
	0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0
};

static const char _tdns_machine_resolvconf_index_offsets[] = {
	0, 8, 10, 12, 16, 20, 21, 29, 
	32, 36, 40, 44, 48, 52, 56, 60, 
	64, 68, 70, 72, 76
};

static const char _tdns_machine_resolvconf_indicies[] = {
	1, 1, 2, 3, 3, 4, 4, 0, 
	5, 0, 5, 6, 7, 7, 8, 6, 
	7, 7, 8, 9, 9, 1, 1, 5, 
	3, 3, 4, 4, 0, 7, 7, 3, 
	5, 10, 10, 0, 5, 11, 11, 0, 
	5, 12, 12, 0, 5, 13, 13, 0, 
	5, 14, 14, 0, 5, 15, 15, 0, 
	5, 16, 16, 0, 5, 17, 17, 0, 
	5, 18, 18, 0, 19, 0, 19, 20, 
	22, 22, 23, 21, 2, 3, 3, 4, 
	4, 0, 0
};

static const char _tdns_machine_resolvconf_trans_targs[] = {
	1, 6, 20, 7, 8, 2, 3, 0, 
	4, 5, 9, 10, 11, 12, 13, 14, 
	15, 16, 17, 18, 19, 19, 0, 4
};

static const char _tdns_machine_resolvconf_trans_actions[] = {
	0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 0, 0, 0, 0, 
	0, 0, 0, 0, 1, 0, 3, 3
};

static const int tdns_machine_resolvconf_start = 0;
static const int tdns_machine_resolvconf_first_final = 0;
static const int tdns_machine_resolvconf_error = -1;

static const int tdns_machine_resolvconf_en_main = 0;


/* #line 101 "./ragel/tnet_dns_resolvconf.rl" */
	TSK_RAGEL_DISABLE_WARNINGS_END()
	(void)(eof);
	(void)(tdns_machine_resolvconf_first_final);
	(void)(tdns_machine_resolvconf_error);
	(void)(tdns_machine_resolvconf_en_main);

	if(tsk_strnullORempty(fullpath)){
		fullpath = TNET_RESOLV_CONF_PATH;
	}

	/* Open the file and read all data */
	if((fd = fopen(fullpath, "r"))){
		long len;
		fseek(fd, 0L, SEEK_END);
		len = ftell(fd);
		fseek(fd, 0L, SEEK_SET);
		if (!(buf = (char*)tsk_calloc(len + 1, 1))) {
			TSK_DEBUG_ERROR("Failed to allocate buffer with size = %ld", (len + 1));
			goto bail;
		}
		fread(buf, 1, len, fd);
		p = &buf[0];
		pe = p + len + 1/*hack*/;
		eof = pe;
		fclose(fd);
		
		buf[len] = '\n'; // hack to have perfect lines

		servers = tsk_list_create();
	}
	else {
#if ANDROID || defined(__APPLE__) /* TARGET_OS_IPHONE not defined for bsd libraries */
		TSK_DEBUG_INFO("Failed to open [%s]. But don't panic, we have detected that you are using Google Android/iOS Systems.\n"
			"You should look at the Progammer's Guide for more information.\n If you are not using DNS functions, don't worry about this warning.", 
			fullpath);
#else
		TSK_DEBUG_ERROR("Failed to open %s.", fullpath);
#endif
		goto bail;
	}

	TSK_RAGEL_DISABLE_WARNINGS_BEGIN()
	
/* #line 186 "./src/dns/tnet_dns_resolvconf.c" */
	{
	cs = tdns_machine_resolvconf_start;
	}

/* #line 144 "./ragel/tnet_dns_resolvconf.rl" */
	
/* #line 193 "./src/dns/tnet_dns_resolvconf.c" */
	{
	int _klen;
	unsigned int _trans;
	const char *_acts;
	unsigned int _nacts;
	const char *_keys;

	if ( p == pe )
		goto _test_eof;
_resume:
	_keys = _tdns_machine_resolvconf_trans_keys + _tdns_machine_resolvconf_key_offsets[cs];
	_trans = _tdns_machine_resolvconf_index_offsets[cs];

	_klen = _tdns_machine_resolvconf_single_lengths[cs];
	if ( _klen > 0 ) {
		const char *_lower = _keys;
		const char *_mid;
		const char *_upper = _keys + _klen - 1;
		while (1) {
			if ( _upper < _lower )
				break;

			_mid = _lower + ((_upper-_lower) >> 1);
			if ( (*p) < *_mid )
				_upper = _mid - 1;
			else if ( (*p) > *_mid )
				_lower = _mid + 1;
			else {
				_trans += (_mid - _keys);
				goto _match;
			}
		}
		_keys += _klen;
		_trans += _klen;
	}

	_klen = _tdns_machine_resolvconf_range_lengths[cs];
	if ( _klen > 0 ) {
		const char *_lower = _keys;
		const char *_mid;
		const char *_upper = _keys + (_klen<<1) - 2;
		while (1) {
			if ( _upper < _lower )
				break;

			_mid = _lower + (((_upper-_lower) >> 1) & ~1);
			if ( (*p) < _mid[0] )
				_upper = _mid - 2;
			else if ( (*p) > _mid[1] )
				_lower = _mid + 2;
			else {
				_trans += ((_mid - _keys)>>1);
				goto _match;
			}
		}
		_trans += _klen;
	}

_match:
	_trans = _tdns_machine_resolvconf_indicies[_trans];
	cs = _tdns_machine_resolvconf_trans_targs[_trans];

	if ( _tdns_machine_resolvconf_trans_actions[_trans] == 0 )
		goto _again;

	_acts = _tdns_machine_resolvconf_actions + _tdns_machine_resolvconf_trans_actions[_trans];
	_nacts = (unsigned int) *_acts++;
	while ( _nacts-- > 0 )
	{
		switch ( *_acts++ )
		{
	case 0:
/* #line 41 "./ragel/tnet_dns_resolvconf.rl" */
	{
		tag_start = p;
	}
	break;
	case 1:
/* #line 45 "./ragel/tnet_dns_resolvconf.rl" */
	{
		int len = (int)(p  - tag_start);
		if(len && len<=sizeof(ip)){
			tnet_address_t *address;
			memset(ip, '\0', sizeof(ip));
			memcpy(ip, tag_start, len);
			TSK_DEBUG_INFO("Adding DNS server = %s:%d", ip, TNET_DNS_SERVER_PORT_DEFAULT);
			
			address = tnet_address_create(ip);
			address->family = tnet_get_family(ip, TNET_DNS_SERVER_PORT_DEFAULT);
			address->dnsserver = 1;
			tsk_list_push_ascending_data(servers, (void**)&address);
		}
	}
	break;
/* #line 288 "./src/dns/tnet_dns_resolvconf.c" */
		}
	}

_again:
	if ( ++p != pe )
		goto _resume;
	_test_eof: {}
	}

/* #line 145 "./ragel/tnet_dns_resolvconf.rl" */
	TSK_RAGEL_DISABLE_WARNINGS_END()
	
	if (cs < 
/* #line 302 "./src/dns/tnet_dns_resolvconf.c" */
0
/* #line 147 "./ragel/tnet_dns_resolvconf.rl" */
 ) {
		TSK_DEBUG_ERROR("Failed to parse %s.", fullpath);
		TSK_OBJECT_SAFE_FREE(servers);
	}

bail:
	TSK_FREE(buf);
	return servers;
}