1/* Internal representation of tunables.
2
3 Copyright (C) 2016-2023 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#ifndef _TUNABLE_TYPES_H_
21#define _TUNABLE_TYPES_H_
22
23/* Note: This header is included in the generated dl-tunables-list.h and
24 only used internally in the tunables implementation in dl-tunables.c. */
25
26#include <stdbool.h>
27#include <stddef.h>
28#include <stdint.h>
29
30typedef enum
31{
32 TUNABLE_TYPE_INT_32,
33 TUNABLE_TYPE_UINT_64,
34 TUNABLE_TYPE_SIZE_T,
35 TUNABLE_TYPE_STRING
36} tunable_type_code_t;
37
38typedef struct
39{
40 tunable_type_code_t type_code;
41 tunable_num_t min;
42 tunable_num_t max;
43} tunable_type_t;
44
45/* Security level for tunables. This decides what to do with individual
46 tunables for AT_SECURE binaries. */
47typedef enum
48{
49 /* Erase the tunable for AT_SECURE binaries so that child processes don't
50 read it. */
51 TUNABLE_SECLEVEL_SXID_ERASE = 0,
52 /* Ignore the tunable for AT_SECURE binaries, but don't erase it, so that
53 child processes can read it. */
54 TUNABLE_SECLEVEL_SXID_IGNORE = 1,
55 /* Read the tunable. */
56 TUNABLE_SECLEVEL_NONE = 2,
57} tunable_seclevel_t;
58
59/* A tunable. */
60struct _tunable
61{
62 const char name[TUNABLE_NAME_MAX]; /* Internal name of the tunable. */
63 tunable_type_t type; /* Data type of the tunable. */
64 tunable_val_t val; /* The value. */
65 bool initialized; /* Flag to indicate that the tunable is
66 initialized. */
67 tunable_seclevel_t security_level; /* Specify the security level for the
68 tunable with respect to AT_SECURE
69 programs. See description of
70 tunable_seclevel_t to see a
71 description of the values.
72
73 Note that even if the tunable is
74 read, it may not get used by the
75 target module if the value is
76 considered unsafe. */
77 /* Compatibility elements. */
78 const char env_alias[TUNABLE_ALIAS_MAX]; /* The compatibility environment
79 variable name. */
80};
81
82typedef struct _tunable tunable_t;
83
84static __always_inline bool
85unsigned_tunable_type (tunable_type_code_t t)
86{
87 switch (t)
88 {
89 case TUNABLE_TYPE_INT_32:
90 return false;
91 case TUNABLE_TYPE_UINT_64:
92 case TUNABLE_TYPE_SIZE_T:
93 return true;
94 case TUNABLE_TYPE_STRING:
95 default:
96 break;
97 }
98 __builtin_unreachable ();
99}
100
101#endif
102