/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2020 Oxide Computer Company
 */

/*
 * Basic program that reads random sensors, mostly ignoring errors. This is in
 * support of the stress test program.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/sensors.h>
#include <unistd.h>
#include <string.h>
#include <err.h>
#include <limits.h>
#include <strings.h>

/*
 * Wait for a random amount in 1500 ms, but make sure to wait at least 10ms.
 */
static uint32_t timeout = 1500;
static uint32_t skew = 10;

int
main(int argc, const char *argv[])
{
        int nsensors = 0, ninst = 0;
        uint32_t ms;

        if (argc != 3) {
                errx(EXIT_FAILURE, "missing required args: ninstance, "
                    "nsensors");
        }

        nsensors = atoi(argv[1]);
        ninst = atoi(argv[2]);
        if (nsensors <= 0 || ninst <= 0) {
                errx(EXIT_FAILURE, "got bad values for some of nesnsors (%u), "
                    "ninst (%u)", nsensors, ninst);
        }

        for (;;) {
                int fd;
                char buf[PATH_MAX];
                uint32_t sens, inst;
                struct timespec ts;
                sensor_ioctl_scalar_t scalar;

                /* 0s based */
                sens = arc4random_uniform(nsensors);
                /* 1s based */
                inst = arc4random_uniform(ninst) + 1;
                (void) snprintf(buf, sizeof (buf),
                    "/dev/sensors/test/test.temp.%u.%u", sens, inst);

                fd = open(buf, O_RDONLY);
                if (fd < 0) {
                        warn("failed to open %s", buf);
                        goto wait;
                }

                bzero(&scalar, sizeof (scalar));
                if (ioctl(fd, SENSOR_IOCTL_SCALAR, &scalar) != 0) {
                        warn("failed to get sensor temperature on %s", buf);
                }

                if (scalar.sis_unit != SENSOR_UNIT_CELSIUS) {
                        warnx("data from sensor %s looks off, expected sensor "
                            "to indicate Celsius, but instead %u", buf,
                            scalar.sis_unit);
                }

                (void) close(fd);
wait:
                ms = arc4random_uniform(timeout) + skew;
                ts.tv_sec = ms / 1000;
                ts.tv_nsec = (ms % 1000) * (NANOSEC / MILLISEC);
                (void) nanosleep(&ts, NULL);
        }
        return (0);
}