#include "lookup.h"
#include "stdio_impl.h"
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <netinet/in.h>

int __get_resolv_conf(struct resolvconf* conf, char* search, size_t search_sz) {
  char line[256];
  unsigned char _buf[256];
  FILE *f, _f;
  int nns = 0;

  conf->ndots = 1;
  conf->timeout = 5;
  conf->attempts = 2;
  if (search)
    *search = 0;

  f = __fopen_rb_ca("/etc/resolv.conf", &_f, _buf, sizeof _buf);
  if (!f)
    switch (errno) {
      case ENOENT:
      case ENOTDIR:
      case EACCES:
        goto no_resolv_conf;
      default:
        return -1;
    }

  while (fgets(line, sizeof line, f)) {
    char *p, *z;
    if (!strchr(line, '\n') && !feof(f)) {
      /* Ignore lines that get truncated rather than
       * potentially misinterpreting them. */
      int c;
      do
        c = getc(f);
      while (c != '\n' && c != EOF);
      continue;
    }
    if (!strncmp(line, "options", 7) && isspace(line[7])) {
      p = strstr(line, "ndots:");
      if (p && isdigit(p[6])) {
        p += 6;
        unsigned long x = strtoul(p, &z, 10);
        if (z != p)
          conf->ndots = x > 15 ? 15 : x;
      }
      p = strstr(line, "attempts:");
      if (p && isdigit(p[6])) {
        p += 6;
        unsigned long x = strtoul(p, &z, 10);
        if (z != p)
          conf->attempts = x > 10 ? 10 : x;
      }
      p = strstr(line, "timeout:");
      if (p && (isdigit(p[8]) || p[8] == '.')) {
        p += 8;
        unsigned long x = strtoul(p, &z, 10);
        if (z != p)
          conf->timeout = x > 60 ? 60 : x;
      }
      continue;
    }
    if (!strncmp(line, "nameserver", 10) && isspace(line[10])) {
      if (nns >= MAXNS)
        continue;
      for (p = line + 11; isspace(*p); p++)
        ;
      for (z = p; *z && !isspace(*z); z++)
        ;
      *z = 0;
      if (__lookup_ipliteral(conf->ns + nns, p, AF_UNSPEC) > 0)
        nns++;
      continue;
    }

    if (!search)
      continue;
    if ((strncmp(line, "domain", 6) && strncmp(line, "search", 6)) ||
        !isspace(line[6]))
      continue;
    for (p = line + 7; isspace(*p); p++)
      ;
    size_t l = strlen(p);
    /* This can never happen anyway with chosen buffer sizes. */
    if (l >= search_sz)
      continue;
    memcpy(search, p, l + 1);
  }

  __fclose_ca(f);

no_resolv_conf:
  if (!nns) {
    __lookup_ipliteral(conf->ns, "127.0.0.1", AF_UNSPEC);
    nns = 1;
  }

  conf->nns = nns;

  return 0;
}