linux/tools/testing/selftests/proc/proc-uptime.h
Frederic Weisbecker 263dda24ff selftests/proc: Assert clock_gettime(CLOCK_BOOTTIME) VS /proc/uptime monotonicity
The first field of /proc/uptime relies on the CLOCK_BOOTTIME clock which
can also be fetched from clock_gettime() API.

Improve the test coverage while verifying the monotonicity of
CLOCK_BOOTTIME accross both interfaces.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230222144649.624380-9-frederic@kernel.org
2023-04-18 16:35:13 +02:00

61 lines
1.6 KiB
C

/*
* Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#undef NDEBUG
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include "proc.h"
static uint64_t clock_boottime(void)
{
struct timespec ts;
int err;
err = clock_gettime(CLOCK_BOOTTIME, &ts);
assert(err >= 0);
return (ts.tv_sec * 100) + (ts.tv_nsec / 10000000);
}
static uint64_t proc_uptime(int fd)
{
uint64_t val1, val2;
char buf[64], *p;
ssize_t rv;
/* save "p < end" checks */
memset(buf, 0, sizeof(buf));
rv = pread(fd, buf, sizeof(buf), 0);
assert(0 <= rv && rv <= sizeof(buf));
buf[sizeof(buf) - 1] = '\0';
p = buf;
val1 = xstrtoull(p, &p);
assert(p[0] == '.');
assert('0' <= p[1] && p[1] <= '9');
assert('0' <= p[2] && p[2] <= '9');
assert(p[3] == ' ');
val2 = (p[1] - '0') * 10 + p[2] - '0';
return val1 * 100 + val2;
}