1 | /* The tunable framework. See the README to know how to use the tunable in |
2 | a glibc module. |
3 | |
4 | Copyright (C) 2016-2017 Free Software Foundation, Inc. |
5 | This file is part of the GNU C Library. |
6 | |
7 | The GNU C Library is free software; you can redistribute it and/or |
8 | modify it under the terms of the GNU Lesser General Public |
9 | License as published by the Free Software Foundation; either |
10 | version 2.1 of the License, or (at your option) any later version. |
11 | |
12 | The GNU C Library is distributed in the hope that it will be useful, |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | Lesser General Public License for more details. |
16 | |
17 | You should have received a copy of the GNU Lesser General Public |
18 | License along with the GNU C Library; if not, see |
19 | <http://www.gnu.org/licenses/>. */ |
20 | |
21 | #ifndef _TUNABLES_H_ |
22 | #define _TUNABLES_H_ |
23 | |
24 | #if !HAVE_TUNABLES |
25 | static inline void |
26 | __always_inline |
27 | __tunables_init (char **unused __attribute__ ((unused))) |
28 | { |
29 | /* This is optimized out if tunables are not enabled. */ |
30 | } |
31 | #else |
32 | |
33 | # include <stddef.h> |
34 | # include "dl-tunable-types.h" |
35 | |
36 | /* A tunable. */ |
37 | struct _tunable |
38 | { |
39 | const char *name; /* Internal name of the tunable. */ |
40 | tunable_type_t type; /* Data type of the tunable. */ |
41 | tunable_val_t val; /* The value. */ |
42 | const char *strval; /* The string containing the value, |
43 | points into envp. */ |
44 | tunable_seclevel_t security_level; /* Specify the security level for the |
45 | tunable with respect to AT_SECURE |
46 | programs. See description of |
47 | tunable_seclevel_t to see a |
48 | description of the values. |
49 | |
50 | Note that even if the tunable is |
51 | read, it may not get used by the |
52 | target module if the value is |
53 | considered unsafe. */ |
54 | /* Compatibility elements. */ |
55 | const char *env_alias; /* The compatibility environment |
56 | variable name. */ |
57 | }; |
58 | |
59 | typedef struct _tunable tunable_t; |
60 | |
61 | /* Full name for a tunable is top_ns.tunable_ns.id. */ |
62 | # define TUNABLE_NAME_S(top,ns,id) #top "." #ns "." #id |
63 | |
64 | # define TUNABLE_ENUM_NAME(top,ns,id) TUNABLE_ENUM_NAME1 (top,ns,id) |
65 | # define TUNABLE_ENUM_NAME1(top,ns,id) top ## _ ## ns ## _ ## id |
66 | |
67 | # include "dl-tunable-list.h" |
68 | |
69 | extern void __tunables_init (char **); |
70 | extern void __tunable_set_val (tunable_id_t, void *, tunable_callback_t); |
71 | |
72 | /* Check if the tunable has been set to a non-default value and if it is, copy |
73 | it over into __VAL. */ |
74 | # define TUNABLE_SET_VAL(__id,__val) \ |
75 | ({ \ |
76 | __tunable_set_val \ |
77 | (TUNABLE_ENUM_NAME (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id), (__val), \ |
78 | NULL); \ |
79 | }) |
80 | |
81 | /* Same as TUNABLE_SET_VAL, but also call the callback function __CB. */ |
82 | # define TUNABLE_SET_VAL_WITH_CALLBACK(__id,__val,__cb) \ |
83 | ({ \ |
84 | __tunable_set_val \ |
85 | (TUNABLE_ENUM_NAME (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id), (__val), \ |
86 | DL_TUNABLE_CALLBACK (__cb)); \ |
87 | }) |
88 | |
89 | /* Namespace sanity for callback functions. Use this macro to keep the |
90 | namespace of the modules clean. */ |
91 | # define DL_TUNABLE_CALLBACK(__name) _dl_tunable_ ## __name |
92 | |
93 | # define TUNABLES_FRONTEND_valstring 1 |
94 | /* The default value for TUNABLES_FRONTEND. */ |
95 | # define TUNABLES_FRONTEND_yes TUNABLES_FRONTEND_valstring |
96 | #endif |
97 | #endif |
98 | |