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
134
135
136
137
138
139
140
141
142
143
144
145
146
|
/* Get file-specific information about a file. Linux version.
Copyright (C) 2003-2015 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/>. */
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sysdep.h>
#include <time.h>
#include <unistd.h>
#include <sys/resource.h>
#include <sys/param.h>
#include <not-cancel.h>
#include <ldsodefs.h>
/* Legacy value of ARG_MAX. The macro is now not defined since the
actual value varies based on the stack size. */
#define legacy_ARG_MAX 131072
static long int posix_sysconf (int name);
#ifndef HAS_CPUCLOCK
static long int
has_cpuclock (int name)
{
# if defined __NR_clock_getres || HP_TIMING_AVAIL
/* If we have HP_TIMING, we will fall back on that if the system
call does not work, so we support it either way. */
# if !HP_TIMING_AVAIL
/* Check using the clock_getres system call. */
struct timespec ts;
INTERNAL_SYSCALL_DECL (err);
int r = INTERNAL_SYSCALL (clock_getres, err, 2,
(name == _SC_CPUTIME
? CLOCK_PROCESS_CPUTIME_ID
: CLOCK_THREAD_CPUTIME_ID),
&ts);
if (INTERNAL_SYSCALL_ERROR_P (r, err))
return -1;
# endif
return _POSIX_VERSION;
# else
return -1;
# endif
}
# define HAS_CPUCLOCK(name) has_cpuclock (name)
#endif
/* Get the value of the system variable NAME. */
long int
__sysconf (int name)
{
const char *procfname = NULL;
switch (name)
{
struct rlimit rlimit;
#ifdef __NR_clock_getres
case _SC_MONOTONIC_CLOCK:
/* Check using the clock_getres system call. */
{
struct timespec ts;
INTERNAL_SYSCALL_DECL (err);
int r;
r = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
return INTERNAL_SYSCALL_ERROR_P (r, err) ? -1 : _POSIX_VERSION;
}
#endif
case _SC_CPUTIME:
case _SC_THREAD_CPUTIME:
return HAS_CPUCLOCK (name);
case _SC_ARG_MAX:
/* Use getrlimit to get the stack limit. */
if (__getrlimit (RLIMIT_STACK, &rlimit) == 0)
return MAX (legacy_ARG_MAX, rlimit.rlim_cur / 4);
return legacy_ARG_MAX;
case _SC_NGROUPS_MAX:
/* Try to read the information from the /proc/sys/kernel/ngroups_max
file. */
procfname = "/proc/sys/kernel/ngroups_max";
break;
case _SC_SIGQUEUE_MAX:
if (__getrlimit (RLIMIT_SIGPENDING, &rlimit) == 0)
return rlimit.rlim_cur;
/* The /proc/sys/kernel/rtsig-max file contains the answer. */
procfname = "/proc/sys/kernel/rtsig-max";
break;
default:
break;
}
if (procfname != NULL)
{
int fd = open_not_cancel_2 (procfname, O_RDONLY);
if (fd != -1)
{
/* This is more than enough, the file contains a single integer. */
char buf[32];
ssize_t n;
n = TEMP_FAILURE_RETRY (read_not_cancel (fd, buf, sizeof (buf) - 1));
close_not_cancel_no_status (fd);
if (n > 0)
{
/* Terminate the string. */
buf[n] = '\0';
char *endp;
long int res = strtol (buf, &endp, 10);
if (endp != buf && (*endp == '\0' || *endp == '\n'))
return res;
}
}
}
return posix_sysconf (name);
}
/* Now the POSIX version. */
#undef __sysconf
#define __sysconf static posix_sysconf
#include <sysdeps/posix/sysconf.c>
|
