cosmopolitan/libc/dns/resolvehoststxt.c
Jōshin e16a7d8f3b
flip et / noet in modelines
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

63 lines
3.3 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/dns/consts.h"
#include "libc/dns/dns.h"
#include "libc/dns/hoststxt.h"
#include "libc/mem/alg.h"
#include "libc/sock/sock.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/af.h"
#include "libc/sysv/errfuns.h"
/**
* Finds address associated with name in HOSTS.TXT table.
*
* @param ht can be GetHostsTxt()
* @param af can be AF_INET, AF_UNSPEC
* @param name can be a local or fully-qualified hostname
* @param addr should point to a struct sockaddr_in; if this function
* succeeds, its sin_family and sin_addr fields will be modified
* @param addrsize is the byte size of addr
* @param canon be used to return a pointer to the canonical name
* @return number of matches found, or -1 w/ errno
* @error EAFNOSUPPORT
*/
int ResolveHostsTxt(const struct HostsTxt *ht, int af, const char *name,
struct sockaddr *addr, uint32_t addrsize,
const char **canon) {
size_t i;
struct sockaddr_in *addr4;
if (af != AF_INET && af != AF_UNSPEC) return eafnosupport();
for (i = 0; i < ht->entries.i; ++i) {
if (!CompareDnsNames(name, ht->strings.p + ht->entries.p[i].name)) {
if (addr) {
if (addrsize < kMinSockaddr4Size) return einval();
addr4 = (struct sockaddr_in *)addr;
addr4->sin_family = AF_INET;
memcpy(&addr4->sin_addr.s_addr, &ht->entries.p[i].ip[0], 4);
}
if (canon) {
*canon = ht->strings.p + ht->entries.p[i].canon;
}
return 1;
}
}
return 0;
}