cosmopolitan/libc/dns/getntnameservers.c
Justine Tunney 3e4fd4b0ad Add epoll and do more release readiness changes
This change also pays off some of the remaining technical debt with
stdio, file descriptors, and memory managemnt polyfills.
2020-11-28 12:01:51 -08:00

89 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;
int64_t hkInterfaces = kNtInvalidHandleValue;
uint32_t keycount = 0;
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)) {
struct sockaddr_in nameserver;
nameserver.sin_family = AF_INET;
nameserver.sin_port = htons(DNS_PORT);
rc = 0;
for (uint32_t i = 0; i < keycount; ++i) {
char16_t value[128], ifaceuuid[64];
uint32_t valuebytes, 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)))) {
char value8[128];
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;
}