mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 04:50:07 +00:00
6f9d4f595e
_res_hconf.initialized was not suitable for use in a multi-threaded environment due to the lack of atomics and memory barriers. Use of it was also unnecessary because _res_hconf_init did the right thing by using __libc_once. This patch fixes the glibc-internal uses by just calling _res_hconf_init unconditionally, and switches to a release MO atomic store for _res_hconf.initialized to fix the glibc side of the synchronization problem (which will maintain backward compatibility, but cannot fix the lack of acquire MO on any glibc-external loads). [BZ #20477] * resolv/res_hconf.c (do_init): Use atomic access. * resolv/res_hconf.h: Add comments. * nscd/aicache.c (addhstaiX): Call _res_hconf_init unconditionally. * nss/getXXbyYY_r.c (REENTRANT_NAME): Likewise. * sysdeps/posix/getaddrinfo.c (gaih_inet): Likewise.
57 lines
2.3 KiB
C
57 lines
2.3 KiB
C
/* Copyright (C) 1993-2016 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by David Mosberger (davidm@azstarnet.com).
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _RES_HCONF_H_
|
|
#define _RES_HCONF_H_
|
|
|
|
#include <netdb.h>
|
|
|
|
#define TRIMDOMAINS_MAX 4
|
|
|
|
struct hconf
|
|
{
|
|
/* We keep the INITIALIZED member only for backwards compatibility. New
|
|
code should just call _res_hconf_init unconditionally. For this field
|
|
to be used safely, users must ensure that either (1) a call to
|
|
_res_hconf_init happens-before any load from INITIALIZED, or (2) an
|
|
assignment of zero to INITIALIZED happens-before any load from it, and
|
|
these loads use acquire MO if the intent is to skip calling
|
|
_res_hconf_init if the load returns a nonzero value. Such acquire MO
|
|
loads will then synchronize with the release MO store to INITIALIZED
|
|
in do_init in res_hconf.c; see pthread_once for more detail. */
|
|
int initialized;
|
|
int unused1;
|
|
int unused2[4];
|
|
int num_trimdomains;
|
|
const char *trimdomain[TRIMDOMAINS_MAX];
|
|
unsigned int flags;
|
|
# define HCONF_FLAG_INITED (1 << 0) /* initialized? */
|
|
# define HCONF_FLAG_SPOOF (1 << 1) /* refuse spoofed addresses */
|
|
# define HCONF_FLAG_SPOOFALERT (1 << 2) /* syslog warning of spoofed */
|
|
# define HCONF_FLAG_REORDER (1 << 3) /* list best address first */
|
|
# define HCONF_FLAG_MULTI (1 << 4) /* see comments for gethtbyname() */
|
|
};
|
|
extern struct hconf _res_hconf;
|
|
|
|
extern void _res_hconf_init (void);
|
|
extern void _res_hconf_trim_domain (char *domain);
|
|
extern void _res_hconf_trim_domains (struct hostent *hp);
|
|
extern void _res_hconf_reorder_addrs (struct hostent *hp);
|
|
|
|
#endif /* _RES_HCONF_H_ */
|