mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
248c6d54bb
Added necessary constants (DNS_TYPE_PTR, NI_NUMERICHOST etc.). Implementation of getnameinfo is similar to getaddrinfo, with internal functions: * ResolveDnsReverse: performs rDNS query and parses the PTR record * ResolveHostsReverse: reads /etc/hosts to map hostname to address Earlier, the HOSTS.txt would only need to be sorted at loading time, because the only kind of lookup was name -> address. Now since address -> name lookups are also possible, so the HostsTxt struct, the sorting method (and the related tests) was changed to reflect this.
67 lines
3.3 KiB
C
67 lines
3.3 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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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/alg/alg.h"
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#include "libc/dns/dns.h"
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#include "libc/dns/hoststxt.h"
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/**
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* Compares hostnames in HOSTS.TXT table.
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* @see CompareDnsNames(), ParseHostsTxt()
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*/
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static int cmphoststxt(const struct HostsTxtEntry *e1,
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const struct HostsTxtEntry *e2, const char *strings) {
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if (e1 == e2) return 0;
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return CompareDnsNames(&strings[e1->name], &strings[e2->name]);
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}
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/**
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* Compares addresses in HOSTS.TXT table.
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* @see ResolveHostsReverse()
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*/
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static int cmphostsaddr(const struct HostsTxtEntry *e1,
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const struct HostsTxtEntry *e2) {
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if (e1 == e2) return 0;
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uint32_t v1 = *((uint32_t *)e1->ip), v2 = *((uint32_t *)e2->ip);
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return (v1 == v2 ? 0 : (v1 > v2 ? 1 : -1));
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}
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/**
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* Sorts entries in HOSTS.TXT table.
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*
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* This function enables ResolveHostsTxt() to be called so hard-coded
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* hostname lookups take logarithmic time; you can blackhole all the
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* spam you want, in your /etc/hosts file.
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*
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* The sorted order, defined by CompareDnsNames(), also makes it
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* possible to efficiently search for subdomains, once the initial sort
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* is done.
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*/
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void SortHostsTxt(struct HostsTxt *ht, int sort_by) {
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if (ht->entries.p) {
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if (sort_by == HOSTSTXT_SORTEDBYNAME) {
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qsort_r(ht->entries.p, ht->entries.i, sizeof(*ht->entries.p),
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(void *)cmphoststxt, ht->strings.p);
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ht->sorted_by = HOSTSTXT_SORTEDBYNAME;
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} else {
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qsort(ht->entries.p, ht->entries.i, sizeof(*ht->entries.p),
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(void *)cmphostsaddr);
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ht->sorted_by = HOSTSTXT_SORTEDBYADDR;
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}
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}
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}
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