/*-*- 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│
╞══════════════════════════════════════════════════════════════════════════════╡
│ This is free and unencumbered software released into the public domain.      │
│                                                                              │
│ Anyone is free to copy, modify, publish, use, compile, sell, or              │
│ distribute this software, either in source code form or as a compiled        │
│ binary, for any purpose, commercial or non-commercial, and by any            │
│ means.                                                                       │
│                                                                              │
│ In jurisdictions that recognize copyright laws, the author or authors        │
│ of this software dedicate any and all copyright interest in the              │
│ software to the public domain. We make this dedication for the benefit       │
│ of the public at large and to the detriment of our heirs and                 │
│ successors. We intend this dedication to be an overt act of                  │
│ relinquishment in perpetuity of all present and future rights to this        │
│ software under copyright law.                                                │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,              │
│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF           │
│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.       │
│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR            │
│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,        │
│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR        │
│ OTHER DEALINGS IN THE SOFTWARE.                                              │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/dns/ent.h"
#include "libc/dns/servicestxt.h"
#include "libc/mem/mem.h"
#include "libc/str/str.h"

struct servent *getservbyport(int port, const char *proto) {
  static struct servent *ptr1, se1;
  static char s_name[DNS_NAME_MAX + 1];
  static char localproto[DNS_NAME_MAX + 1];
  if (!ptr1) {
    se1.s_name = s_name;
    if (!(se1.s_aliases = calloc(1, sizeof(char *)))) return NULL;
    se1.s_port = 0;
    se1.s_proto = localproto;
    ptr1 = &se1;
  }
  if (proto) {
    if (!memccpy(localproto, proto, '\0', DNS_NAME_MAX)) return NULL;
  } else
    strcpy(localproto, "");
  if (LookupServicesByPort(ntohs(port), ptr1->s_proto, DNS_NAME_MAX,
                           ptr1->s_name, DNS_NAME_MAX, NULL) == -1) {
    return NULL;
  }
  ptr1->s_port = port;
  return ptr1;
}