blob: 152c968d694e7af10581138301076a85fd0dab2e (
plain) (
blame)
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
|
/* Copyright (C) 2000-2015 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 <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <not-cancel.h>
static int itc_usable;
static int
has_cpuclock (void)
{
if (__builtin_expect (itc_usable == 0, 0))
{
int newval = 1;
int fd = open_not_cancel_2 ("/proc/sal/itc_drift", O_RDONLY);
if (__builtin_expect (fd != -1, 1))
{
char buf[16];
/* We expect the file to contain a single digit followed by
a newline. If the format changes we better not rely on
the file content. */
if (read_not_cancel (fd, buf, sizeof buf) != 2
|| buf[0] != '0' || buf[1] != '\n')
newval = -1;
close_not_cancel_no_status (fd);
}
itc_usable = newval;
}
return itc_usable;
}
|
