1/* Get system load averages. Linux (/proc/loadavg) version.
2 Copyright (C) 1999-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <fcntl.h>
21#include <locale.h>
22#include <stdlib.h>
23#include <unistd.h>
24#include <not-cancel.h>
25
26/* Put the 1 minute, 5 minute and 15 minute load averages
27 into the first NELEM elements of LOADAVG.
28 Return the number written (never more than 3, but may be less than NELEM),
29 or -1 if an error occurred. */
30
31int
32getloadavg (double loadavg[], int nelem)
33{
34 int fd;
35
36 fd = __open_nocancel ("/proc/loadavg", O_RDONLY);
37 if (fd < 0)
38 return -1;
39 else
40 {
41 char buf[65], *p;
42 ssize_t nread;
43 int i;
44
45 nread = __read_nocancel (fd, buf, sizeof buf - 1);
46 __close_nocancel_nostatus (fd);
47 if (nread <= 0)
48 return -1;
49 buf[nread - 1] = '\0';
50
51 if (nelem > 3)
52 nelem = 3;
53 p = buf;
54 for (i = 0; i < nelem; ++i)
55 {
56 char *endp;
57 loadavg[i] = __strtod_l (p, &endp, _nl_C_locobj_ptr);
58 if (endp == p)
59 /* This should not happen. The format of /proc/loadavg
60 must have changed. Don't return with what we have,
61 signal an error. */
62 return -1;
63 p = endp;
64 }
65
66 return i;
67 }
68}
69