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// Test that values in /proc/uptime increment monotonically
17// while shifting across CPUs.
18#undef NDEBUG
19#include <assert.h>
20#include <errno.h>
21#include <unistd.h>
22#include <sys/syscall.h>
23#include <stdlib.h>
24#include <string.h>
25
26#include <stdint.h>
27#include <sys/types.h>
28#include <sys/stat.h>
29#include <fcntl.h>
30
31#include "proc-uptime.h"
32
33static inline int sys_sched_getaffinity(pid_t pid, unsigned int len, unsigned long *m)
34{
35	return syscall(SYS_sched_getaffinity, pid, len, m);
36}
37
38static inline int sys_sched_setaffinity(pid_t pid, unsigned int len, unsigned long *m)
39{
40	return syscall(SYS_sched_setaffinity, pid, len, m);
41}
42
43int main(void)
44{
45	unsigned int len;
46	unsigned long *m;
47	unsigned int cpu;
48	uint64_t u0, u1, i0, i1;
49	int fd;
50
51	/* find out "nr_cpu_ids" */
52	m = NULL;
53	len = 0;
54	do {
55		len += sizeof(unsigned long);
56		free(m);
57		m = malloc(len);
58	} while (sys_sched_getaffinity(0, len, m) == -1 && errno == EINVAL);
59
60	fd = open("/proc/uptime", O_RDONLY);
61	assert(fd >= 0);
62
63	proc_uptime(fd, &u0, &i0);
64	for (cpu = 0; cpu < len * 8; cpu++) {
65		memset(m, 0, len);
66		m[cpu / (8 * sizeof(unsigned long))] |= 1UL << (cpu % (8 * sizeof(unsigned long)));
67
68		/* CPU might not exist, ignore error */
69		sys_sched_setaffinity(0, len, m);
70
71		proc_uptime(fd, &u1, &i1);
72		assert(u1 >= u0);
73		assert(i1 >= i0);
74		u0 = u1;
75		i0 = i1;
76	}
77
78	return 0;
79}