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hesiod: Always use thread-local resolver state [BZ #19573]

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The Hesiod implementation imported into glibc was enhanced
to support caller-supplied resolver states.  But its only
consumer is nss_hesiod, and it supplies the thread-local
resolver state.  Therefore, this commit changes the Hesiod
implementation to use the thread-local resolver state (_res)
directly.  This fixes bug 19573 because the Hesiod
implementation no longer has to initialize and free any
resolver state.

To avoid any risk of interposition of ABI-incompatible Hesiod
function implementations, this commit marks the Hesiod functions
as hidden.  (They were already hidden using a linker version
script.)
This commit is contained in:
Florian Weimer
2016-05-02 15:25:20 +02:00
parent 46cb402c6d
commit 5018f16c62
11 changed files with 89 additions and 156 deletions
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85
hesiod/hesiod.c
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@@ -1,3 +1,20 @@
/* Copyright (C) 1997-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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/>. */
/*
* Copyright (c) 1996,1999 by Internet Software Consortium.
*
@@ -47,18 +64,9 @@
/* Forward */
int hesiod_init(void **context);
void hesiod_end(void *context);
char * hesiod_to_bind(void *context, const char *name,
const char *type);
char ** hesiod_resolve(void *context, const char *name,
const char *type);
void hesiod_free_list(void *context, char **list);
static int parse_config_file(struct hesiod_p *ctx, const char *filename);
static char ** get_txt_records(struct hesiod_p *ctx, int class,
const char *name);
static int init(struct hesiod_p *ctx);
/* Public */
@@ -77,7 +85,6 @@ hesiod_init(void **context) {
ctx->LHS = NULL;
ctx->RHS = NULL;
ctx->res = NULL;
/* Set default query classes. */
ctx->classes[0] = C_IN;
ctx->classes[1] = C_HS;
@@ -114,11 +121,6 @@ hesiod_init(void **context) {
goto cleanup;
}
#if 0
if (res_ninit(ctx->res) < 0)
goto cleanup;
#endif
*context = ctx;
return (0);
@@ -135,12 +137,8 @@ hesiod_end(void *context) {
struct hesiod_p *ctx = (struct hesiod_p *) context;
int save_errno = errno;
if (ctx->res)
res_nclose(ctx->res);
free(ctx->RHS);
free(ctx->LHS);
if (ctx->res && ctx->free_res)
(*ctx->free_res)(ctx->res);
free(ctx);
__set_errno(save_errno);
}
@@ -215,10 +213,6 @@ hesiod_resolve(void *context, const char *name, const char *type) {
if (bindname == NULL)
return (NULL);
if (init(ctx) == -1) {
free(bindname);
return (NULL);
}
retvec = get_txt_records(ctx, ctx->classes[0], bindname);
@@ -348,13 +342,13 @@ get_txt_records(struct hesiod_p *ctx, int class, const char *name) {
/*
* Construct the query and send it.
*/
n = res_nmkquery(ctx->res, QUERY, name, class, T_TXT, NULL, 0,
n = res_mkquery(QUERY, name, class, T_TXT, NULL, 0,
NULL, qbuf, MAX_HESRESP);
if (n < 0) {
__set_errno(EMSGSIZE);
return (NULL);
}
n = res_nsend(ctx->res, qbuf, n, abuf, MAX_HESRESP);
n = res_send(qbuf, n, abuf, MAX_HESRESP);
if (n < 0) {
__set_errno(ECONNREFUSED);
return (NULL);
@@ -447,44 +441,3 @@ get_txt_records(struct hesiod_p *ctx, int class, const char *name) {
free(list);
return (NULL);
}
struct __res_state *
__hesiod_res_get(void *context) {
struct hesiod_p *ctx = context;
if (!ctx->res) {
struct __res_state *res;
res = (struct __res_state *)calloc(1, sizeof *res);
if (res == NULL)
return (NULL);
__hesiod_res_set(ctx, res, free);
}
return (ctx->res);
}
void
__hesiod_res_set(void *context, struct __res_state *res,
void (*free_res)(void *)) {
struct hesiod_p *ctx = context;
if (ctx->res && ctx->free_res) {
res_nclose(ctx->res);
(*ctx->free_res)(ctx->res);
}
ctx->res = res;
ctx->free_res = free_res;
}
static int
init(struct hesiod_p *ctx) {
if (!ctx->res && !__hesiod_res_get(ctx))
return (-1);
if (__res_maybe_init (ctx->res, 0) == -1)
return (-1);
return (0);
}