1 /*
2  * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 #undef NDEBUG
17 #include <assert.h>
18 #include <errno.h>
19 #include <string.h>
20 #include <stdlib.h>
21 #include <unistd.h>
22 
23 #include "proc.h"
24 
proc_uptime(int fd,uint64_t * uptime,uint64_t * idle)25 static void proc_uptime(int fd, uint64_t *uptime, uint64_t *idle)
26 {
27 	uint64_t val1, val2;
28 	char buf[64], *p;
29 	ssize_t rv;
30 
31 	/* save "p < end" checks */
32 	memset(buf, 0, sizeof(buf));
33 	rv = pread(fd, buf, sizeof(buf), 0);
34 	assert(0 <= rv && rv <= sizeof(buf));
35 	buf[sizeof(buf) - 1] = '\0';
36 
37 	p = buf;
38 
39 	val1 = xstrtoull(p, &p);
40 	assert(p[0] == '.');
41 	assert('0' <= p[1] && p[1] <= '9');
42 	assert('0' <= p[2] && p[2] <= '9');
43 	assert(p[3] == ' ');
44 
45 	val2 = (p[1] - '0') * 10 + p[2] - '0';
46 	*uptime = val1 * 100 + val2;
47 
48 	p += 4;
49 
50 	val1 = xstrtoull(p, &p);
51 	assert(p[0] == '.');
52 	assert('0' <= p[1] && p[1] <= '9');
53 	assert('0' <= p[2] && p[2] <= '9');
54 	assert(p[3] == '\n');
55 
56 	val2 = (p[1] - '0') * 10 + p[2] - '0';
57 	*idle = val1 * 100 + val2;
58 
59 	assert(p + 4 == buf + rv);
60 }
61