1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/* The tunable framework. See the README to know how to use the tunable in
a glibc module.
Copyright (C) 2016-2021 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
<https://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 <stdbool.h>
# include <stddef.h>
# include <stdint.h>
typedef union
{
int64_t numval;
const char *strval;
} tunable_val_t;
typedef void (*tunable_callback_t) (tunable_val_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 __tunables_print (void);
extern void __tunable_get_val (tunable_id_t, void *, tunable_callback_t);
extern void __tunable_set_val (tunable_id_t, void *, void *, void *);
rtld_hidden_proto (__tunables_init)
rtld_hidden_proto (__tunables_print)
rtld_hidden_proto (__tunable_get_val)
rtld_hidden_proto (__tunable_set_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)
# define TUNABLE_SET_WITH_BOUNDS(__id, __type, __val, __min, __max) \
TUNABLE_SET_WITH_BOUNDS_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, \
__type, __val, __min, __max)
#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)
# define TUNABLE_SET_WITH_BOUNDS(__top, __ns, __id, __type, __val, \
__min, __max) \
TUNABLE_SET_WITH_BOUNDS_FULL (__top, __ns, __id, __type, __val, \
__min, __max)
#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}, NULL, NULL); \
})
/* Set a tunable value together with min/max values. */
# define TUNABLE_SET_WITH_BOUNDS_FULL(__top, __ns, __id, __type, __val, \
__min, __max) \
({ \
__tunable_set_val (TUNABLE_ENUM_NAME (__top, __ns, __id), \
& (__type) {__val}, & (__type) {__min}, \
& (__type) {__max}); \
})
/* 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 __always_inline bool
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
|
