cosmopolitan/libc/dns/getntnameservers.c

92 lines
4.8 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ 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; version 2 of the License. │
│ │
│ 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 "libc/alg/arraylist.internal.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/dns/dns.h"
#include "libc/dns/resolvconf.h"
#include "libc/nt/enum/keyaccess.h"
#include "libc/nt/enum/reggetvalueflags.h"
#include "libc/nt/registry.h"
#include "libc/nt/runtime.h"
#include "libc/runtime/runtime.h"
#include "libc/sock/sock.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/af.h"
/**
* Extracts DNS nameserver IPs from Windows Registry.
*
* @param resolv points to a ResolvConf object, which should be zero
* initialized by the caller; or if it already contains items,
* this function will append
* @return number of nameservers appended, or -1 w/ errno
*/
textwindows int getntnameservers(struct ResolvConf *resolv) {
int rc;
char value8[128];
int64_t hkInterfaces;
struct sockaddr_in nameserver;
char16_t value[128], ifaceuuid[64];
uint32_t i, keycount, valuebytes, ifaceuuidlen;
keycount = 0;
hkInterfaces = kNtInvalidHandleValue;
if (!RegOpenKeyEx(
kNtHkeyLocalMachine,
u"SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces",
0, kNtKeyRead, &hkInterfaces) &&
!RegQueryInfoKey(hkInterfaces, NULL, NULL, NULL, &keycount, NULL, NULL,
NULL, NULL, NULL, NULL, NULL)) {
nameserver.sin_family = AF_INET;
nameserver.sin_port = htons(DNS_PORT);
rc = 0;
for (i = 0; i < keycount; ++i) {
ifaceuuidlen = sizeof(ifaceuuid);
if (!RegEnumKeyEx(hkInterfaces, i, ifaceuuid, &ifaceuuidlen, NULL, NULL,
NULL, NULL) &&
((!RegGetValue(hkInterfaces, ifaceuuid, u"DhcpIpAddress",
kNtRrfRtRegSz | kNtRrfRtRegMultiSz, NULL, value,
((valuebytes = sizeof(value)), &valuebytes)) &&
valuebytes > 2 * sizeof(char16_t)) ||
(!RegGetValue(hkInterfaces, ifaceuuid, u"IpAddress",
kNtRrfRtRegSz | kNtRrfRtRegMultiSz, NULL, value,
((valuebytes = sizeof(value)), &valuebytes)) &&
valuebytes > 2 * sizeof(char16_t))) &&
((!RegGetValue(hkInterfaces, ifaceuuid, u"DhcpNameServer",
kNtRrfRtRegSz | kNtRrfRtRegMultiSz, NULL, value,
((valuebytes = sizeof(value)), &valuebytes)) &&
valuebytes > 2 * sizeof(char16_t)) ||
(!RegGetValue(hkInterfaces, ifaceuuid, u"NameServer",
kNtRrfRtRegSz | kNtRrfRtRegMultiSz, NULL, value,
((valuebytes = sizeof(value)), &valuebytes)) &&
valuebytes > 2 * sizeof(char16_t)))) {
tprecode16to8(value8, sizeof(value8), value);
if (inet_pton(AF_INET, value8, &nameserver.sin_addr.s_addr) == 1) {
if (append(&resolv->nameservers, &nameserver) != -1) ++rc;
}
}
}
} else {
rc = __winerr();
}
RegCloseKey(hkInterfaces);
return rc;
}