/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"

#include "hostpid.h"

#include <unistd.h>

#include <netdb.h>

#define HOSTNAME_DISALLOWED_CHARS "/\r\n\t"

const char *my_hostname = NULL;

const char *my_pid = NULL;

static char *my_hostname_dup = NULL;

static char *my_domain = NULL;

void hostpid_init(void)

{

  static char pid[MAX_INT_STRLEN];

  char hostname[256];

  const char *value;

  /* allow calling hostpid_init() multiple times to reset hostname */

  i_free_and_null(my_hostname_dup);

  i_free_and_null(my_domain);

  value = getenv(MY_HOSTNAME_ENV);

  if (value == NULL) {

    if (gethostname(hostname, sizeof(hostname)-1) < 0)

      i_fatal("gethostname() failed: %m");

    hostname[sizeof(hostname)-1] = '\0';

    value = hostname;

  }

  if (value[0] == '\0' ||

      strcspn(value, HOSTNAME_DISALLOWED_CHARS) != strlen(value))

    i_fatal("Invalid system hostname: '%s'", value);

  my_hostname_dup = i_strdup(value);

  my_hostname = my_hostname_dup;

  i_snprintf(pid, sizeof(pid), "%lld", (long long)getpid());

  my_pid = pid;

}

void hostpid_deinit(void)

{

  i_free(my_hostname_dup);

  i_free(my_domain);

}

const char *my_hostdomain(void)

{

  const char *name;

  const struct addrinfo hints = {

    .ai_family = AF_UNSPEC,

    .ai_socktype = SOCK_STREAM,

    .ai_flags = AI_CANONNAME,

  };

  struct addrinfo *res;

  if (my_domain != NULL)

    return my_domain;

  name = getenv(MY_HOSTDOMAIN_ENV);

  if (name != NULL) {

    my_domain = i_strdup(name);

    return my_domain;

  }

  if (getaddrinfo(my_hostname, NULL, &hints, &res) == 0) {

    my_domain = i_strdup(res->ai_canonname);

    freeaddrinfo(res);

    return my_domain;

  }

  /* failed, use just the hostname */

  my_domain = i_strdup(my_hostname);

  return my_domain;

}