libwebsockets/lib/plat/unix/unix-resolv.c

93 lines
2.7 KiB
C

/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "private-lib-core.h"
#include "private-lib-async-dns.h"
lws_async_dns_server_check_t
lws_plat_asyncdns_init(struct lws_context *context, lws_async_dns_t *dns)
{
lws_async_dns_server_check_t s = LADNS_CONF_SERVER_SAME;
lws_async_dns_server_t *dsrv;
lws_sockaddr46 sa46t;
lws_tokenize_t ts;
char ads[48], *r;
int fd, ns = 0;
ssize_t n;
r = (char *)context->pt[0].serv_buf;
/* grab the first chunk of /etc/resolv.conf */
fd = open("/etc/resolv.conf", LWS_O_RDONLY);
if (fd < 0)
return LADNS_CONF_SERVER_UNKNOWN;
n = read(fd, r, context->pt_serv_buf_size - 1);
close(fd);
if (n < 0)
return LADNS_CONF_SERVER_UNKNOWN;
r[n] = '\0';
lws_tokenize_init(&ts, r, LWS_TOKENIZE_F_DOT_NONTERM |
LWS_TOKENIZE_F_NO_FLOATS |
LWS_TOKENIZE_F_NO_INTEGERS |
LWS_TOKENIZE_F_MINUS_NONTERM |
LWS_TOKENIZE_F_HASH_COMMENT);
do {
ts.e = (int8_t)lws_tokenize(&ts);
if (ts.e != LWS_TOKZE_TOKEN) {
ns = 0;
continue;
}
if (!ns && !strncmp("nameserver", ts.token, ts.token_len)) {
ns = 1;
continue;
}
if (!ns)
continue;
/* we are a token just after the "nameserver" token */
ns = 0;
if (ts.token_len > (int)sizeof(ads) - 1)
continue;
memcpy(ads, ts.token, ts.token_len);
ads[ts.token_len] = '\0';
if (lws_sa46_parse_numeric_address(ads, &sa46t) < 0)
continue;
dsrv = __lws_async_dns_server_find(dns, &sa46t);
if (!dsrv) {
__lws_async_dns_server_add(dns, &sa46t);
s = LADNS_CONF_SERVER_CHANGED;
}
} while (ts.e > 0);
return s;
}