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/*
* Copyright (c) 2021 Yubico AB. All rights reserved.
* Use of this source code is governed by a BSD-style
* license that can be found in the LICENSE file.
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <stdint.h>
#include <time.h>
#include "mutator_aux.h"
/*
* A pseudo-random monotonic clock with a probabilistic discontinuity to
* the end of time (as measured by struct timespec).
*/
extern int prng_up;
extern int __wrap_clock_gettime(clockid_t, struct timespec *);
extern int __real_clock_gettime(clockid_t, struct timespec *);
extern int __wrap_usleep(unsigned int);
static TLS struct timespec fuzz_clock;
static void
tick(unsigned int usec)
{
long long drift;
/*
* Simulate a jump to the end of time with 0.125% probability.
* This condition should be gracefully handled by callers of
* clock_gettime().
*/
if (uniform_random(800) < 1) {
fuzz_clock.tv_sec = LLONG_MAX;
fuzz_clock.tv_nsec = LONG_MAX;
return;
}
drift = usec * 1000LL + (long long)uniform_random(10000000); /* 10ms */
if (LLONG_MAX - drift < (long long)fuzz_clock.tv_nsec) {
fuzz_clock_reset(); /* Not much we can do here. */
} else if (drift + (long long)fuzz_clock.tv_nsec < 1000000000) {
fuzz_clock.tv_nsec += (long)(drift);
} else {
fuzz_clock.tv_sec += (long)(drift / 1000000000);
fuzz_clock.tv_nsec += (long)(drift % 1000000000);
}
}
int
__wrap_clock_gettime(clockid_t clk_id, struct timespec *tp)
{
if (!prng_up || clk_id != CLOCK_MONOTONIC)
return __real_clock_gettime(clk_id, tp);
if (uniform_random(400) < 1)
return -1;
tick(0);
*tp = fuzz_clock;
return 0;
}
int
__wrap_usleep(unsigned int usec)
{
if (uniform_random(400) < 1)
return -1;
tick(usec);
return 0;
}
void
fuzz_clock_reset(void)
{
memset(&fuzz_clock, 0, sizeof(fuzz_clock));
}
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