71 lines
3.7 KiB
C
71 lines
3.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/alg/alg.h"
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#include "libc/dns/consts.h"
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#include "libc/dns/dns.h"
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#include "libc/dns/hoststxt.h"
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#include "libc/sock/sock.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/af.h"
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#include "libc/sysv/errfuns.h"
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static int hoststxtgetcmp(const char *node, const struct HostsTxtEntry *entry,
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const char *strings) {
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return dnsnamecmp(node, &strings[entry->name]);
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}
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/**
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* Finds address associated with name in HOSTS.TXT table.
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*
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* This function performs binary search, so sorthoststxt() must be
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* called on the table beforehand.
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*
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* @param ht can be gethoststxt()
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* @param af can be AF_INET, AF_UNSPEC
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* @param name can be a local or fully-qualified hostname
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* @param addr should point to a struct sockaddr_in; if this function
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* succeeds, its sin_family and sin_addr fields will be modified
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* @param addrsize is the byte size of addr
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* @param canon be used to return a pointer to the canonical name
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* @return number of matches found, or -1 w/ errno
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* @error EAFNOSUPPORT
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*/
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int resolvehoststxt(const struct HostsTxt *ht, int af, const char *name,
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struct sockaddr *addr, uint32_t addrsize,
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const char **canon) {
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struct sockaddr_in *addr4;
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struct HostsTxtEntry *entry;
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if (af != AF_INET && af != AF_UNSPEC) return eafnosupport();
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if ((entry = bsearch_r(name, ht->entries.p, ht->entries.i,
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sizeof(struct HostsTxtEntry), (void *)hoststxtgetcmp,
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ht->strings.p))) {
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if (addr) {
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if (addrsize < kMinSockaddr4Size) return einval();
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addr4 = (struct sockaddr_in *)addr;
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addr4->sin_family = AF_INET;
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memcpy(&addr4->sin_addr.s_addr, &entry->ip[0], 4);
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}
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if (canon) *canon = &ht->strings.p[entry->canon];
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return 1;
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} else {
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return 0;
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}
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}
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