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+/* The tunable framework. See the README to know how to use the tunable in
+ a glibc module.
+
+ Copyright (C) 2016-2018 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/>. */
+
+#ifndef _TUNABLES_H_
+#define _TUNABLES_H_
+
+#if !HAVE_TUNABLES
+static inline void
+__always_inline
+__tunables_init (char **unused __attribute__ ((unused)))
+{
+ /* This is optimized out if tunables are not enabled. */
+}
+#else
+
+# include <stddef.h>
+# include "dl-tunable-types.h"
+
+/* A tunable. */
+struct _tunable
+{
+ const char *name; /* Internal name of the tunable. */
+ tunable_type_t type; /* Data type of the tunable. */
+ tunable_val_t val; /* The value. */
+ bool initialized; /* Flag to indicate that the tunable is
+ initialized. */
+ tunable_seclevel_t security_level; /* Specify the security level for the
+ tunable with respect to AT_SECURE
+ programs. See description of
+ tunable_seclevel_t to see a
+ description of the values.
+
+ Note that even if the tunable is
+ read, it may not get used by the
+ target module if the value is
+ considered unsafe. */
+ /* Compatibility elements. */
+ const char *env_alias; /* The compatibility environment
+ variable name. */
+};
+
+typedef struct _tunable tunable_t;
+
+/* Full name for a tunable is top_ns.tunable_ns.id. */
+# define TUNABLE_NAME_S(top,ns,id) #top "." #ns "." #id
+
+# define TUNABLE_ENUM_NAME(__top,__ns,__id) TUNABLE_ENUM_NAME1 (__top,__ns,__id)
+# define TUNABLE_ENUM_NAME1(__top,__ns,__id) __top ## _ ## __ns ## _ ## __id
+
+# include "dl-tunable-list.h"
+
+extern void __tunables_init (char **);
+extern void __tunable_get_val (tunable_id_t, void *, tunable_callback_t);
+extern void __tunable_set_val (tunable_id_t, void *);
+rtld_hidden_proto (__tunables_init)
+rtld_hidden_proto (__tunable_get_val)
+
+/* Define TUNABLE_GET and TUNABLE_SET in short form if TOP_NAMESPACE and
+ TUNABLE_NAMESPACE are defined. This is useful shorthand to get and set
+ tunables within a module. */
+#if defined TOP_NAMESPACE && defined TUNABLE_NAMESPACE
+# define TUNABLE_GET(__id, __type, __cb) \
+ TUNABLE_GET_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, __type, __cb)
+# define TUNABLE_SET(__id, __type, __val) \
+ TUNABLE_SET_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, __type, __val)
+#else
+# define TUNABLE_GET(__top, __ns, __id, __type, __cb) \
+ TUNABLE_GET_FULL (__top, __ns, __id, __type, __cb)
+# define TUNABLE_SET(__top, __ns, __id, __type, __val) \
+ TUNABLE_SET_FULL (__top, __ns, __id, __type, __val)
+#endif
+
+/* Get and return a tunable value. If the tunable was set externally and __CB
+ is defined then call __CB before returning the value. */
+# define TUNABLE_GET_FULL(__top, __ns, __id, __type, __cb) \
+({ \
+ tunable_id_t id = TUNABLE_ENUM_NAME (__top, __ns, __id); \
+ __type ret; \
+ __tunable_get_val (id, &ret, __cb); \
+ ret; \
+})
+
+/* Set a tunable value. */
+# define TUNABLE_SET_FULL(__top, __ns, __id, __type, __val) \
+({ \
+ __tunable_set_val (TUNABLE_ENUM_NAME (__top, __ns, __id), \
+ & (__type) {__val}); \
+})
+
+/* Namespace sanity for callback functions. Use this macro to keep the
+ namespace of the modules clean. */
+# define TUNABLE_CALLBACK(__name) _dl_tunable_ ## __name
+
+# define TUNABLES_FRONTEND_valstring 1
+/* The default value for TUNABLES_FRONTEND. */
+# define TUNABLES_FRONTEND_yes TUNABLES_FRONTEND_valstring
+
+/* Compare two name strings, bounded by the name hardcoded in glibc. */
+static inline bool
+__always_inline
+tunable_is_name (const char *orig, const char *envname)
+{
+ for (;*orig != '\0' && *envname != '\0'; envname++, orig++)
+ if (*orig != *envname)
+ break;
+
+ /* The ENVNAME is immediately followed by a value. */
+ if (*orig == '\0' && *envname == '=')
+ return true;
+ else
+ return false;
+}
+
+#endif
+#endif