/*

 *  Unix SMB/CIFS implementation.

 *  Internal DNS query structures

 *  Copyright (C) Volker Lendecke 2018

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 3 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, see <http://www.gnu.org/licenses/>.

 */

#include "replace.h"

#include <stdio.h>

#include <errno.h>

#include "libcli/dns/resolvconf.h"

#include "lib/util/memory.h"

int parse_resolvconf_fp(

  FILE *fp,

  TALLOC_CTX *mem_ctx,

  char ***pnameservers,

  size_t *pnum_nameservers)

{

  char *line = NULL;

  size_t len = 0;

  char **nameservers = NULL;

  size_t num_nameservers = 0;

  int ret = 0;

  while (true) {

    char *saveptr = NULL, *option = NULL, *ns = NULL;

    char **tmp = NULL;

    ssize_t n = 0;

    n = getline(&line, &len, fp);

    if (n < 0) {

      if (!feof(fp)) {

        /* real error */

        ret = errno;

      }

      break;

    }

    if ((n > 0) && (line[n-1] == '\n')) {

      line[n-1] = '\0';

    }

    if ((line[0] == '#') || (line[0] == ';')) {

      continue;

    }

    option = strtok_r(line, " \t", &saveptr);

    if (option == NULL) {

      continue;

    }

    if (strcmp(option, "nameserver") != 0) {

      continue;

    }

    ns = strtok_r(NULL, " \t", &saveptr);

    if (ns == NULL) {

      continue;

    }

    tmp = talloc_realloc(

      mem_ctx,

      nameservers,

      char *,

      num_nameservers+1);

    if (tmp == NULL) {

      ret = ENOMEM;

      break;

    }

    nameservers = tmp;

    nameservers[num_nameservers] = talloc_strdup(nameservers, ns);

    if (nameservers[num_nameservers] == NULL) {

      ret = ENOMEM;

      break;

    }

    num_nameservers += 1;

  }

  SAFE_FREE(line);

  if (ret == 0) {

    *pnameservers = nameservers;

    *pnum_nameservers = num_nameservers;

  } else {

    TALLOC_FREE(nameservers);

  }

  return ret;

}

int parse_resolvconf(

  const char *resolvconf,

  TALLOC_CTX *mem_ctx,

  char ***pnameservers,

  size_t *pnum_nameservers)

{

  FILE *fp;

  int ret;

  fp = fopen(resolvconf ? resolvconf : "/etc/resolv.conf", "r");

  if (fp == NULL) {

    return errno;

  }

  ret = parse_resolvconf_fp(fp, mem_ctx, pnameservers, pnum_nameservers);

  fclose(fp);

  return ret;

}