resolv/res_hconf.h

   1 /* Copyright (C) 1993-2020 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by David Mosberger (davidm@azstarnet.com).
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _RES_HCONF_H_
  20 #define _RES_HCONF_H_
  21
  22 #include <netdb.h>
  23
  24 #define TRIMDOMAINS_MAX 4
  25
  26 struct hconf
  27 {
  28   /* We keep the INITIALIZED member only for backwards compatibility.  New
  29      code should just call _res_hconf_init unconditionally.  For this field
  30      to be used safely, users must ensure that either (1) a call to
  31      _res_hconf_init happens-before any load from INITIALIZED, or (2) an
  32      assignment of zero to INITIALIZED happens-before any load from it, and
  33      these loads use acquire MO if the intent is to skip calling
  34      _res_hconf_init if the load returns a nonzero value.  Such acquire MO
  35      loads will then synchronize with the release MO store to INITIALIZED
  36      in do_init in res_hconf.c; see pthread_once for more detail.  */
  37   int initialized;
  38   int unused1;
  39   int unused2[4];
  40   int num_trimdomains;
  41   const char *trimdomain[TRIMDOMAINS_MAX];
  42   unsigned int flags;
  43 #  define HCONF_FLAG_INITED     (1 << 0) /* initialized? */
  44 #  define HCONF_FLAG_REORDER    (1 << 3) /* list best address first */
  45 #  define HCONF_FLAG_MULTI      (1 << 4) /* see comments for gethtbyname() */
  46 };
  47 extern struct hconf _res_hconf;
  48
  49 extern void _res_hconf_init (void) attribute_hidden;
  50 extern void _res_hconf_trim_domain (char *domain);
  51 extern void _res_hconf_trim_domains (struct hostent *hp);
  52 extern void _res_hconf_reorder_addrs (struct hostent *hp);
  53
  54 #endif /* _RES_HCONF_H_ */