120 lines
2.5 KiB
C
120 lines
2.5 KiB
C
/*
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* SPDX-License-Identifier: MIT
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*/
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#include <sys/types.h>
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#include <time.h>
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#include <stdbool.h>
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#include <unistd.h>
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#include <pthread.h>
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#include <stdlib.h>
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#include <evl/thread.h>
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#include <evl/mutex.h>
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#include <evl/clock.h>
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#include <evl/sem.h>
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#include "helpers.h"
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#define LOW_PRIO 1
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#define HIGH_PRIO 2
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struct test_context {
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struct evl_mutex lock;
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struct evl_sem start;
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bool acquired;
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};
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static void *victim(void *arg)
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{
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struct test_context *p = arg;
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int ret, tfd;
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if (!__Tcall(tfd, evl_attach_self("monitor-victim:%d", getpid())))
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return (void *)(long)tfd;
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/*
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* Drop the only fileref on this thread so that its resources
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* are released right after it exits.
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*/
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close(tfd);
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if (!__Tcall(ret, evl_get_sem(&p->start)))
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return (void *)(long)ret;
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if (!__Tcall(ret, evl_lock_mutex(&p->lock)))
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return (void *)(long)ret;
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p->acquired = true;
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if (!__Tcall(ret, evl_unlock_mutex(&p->lock)))
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return (void *)(long)ret;
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return NULL;
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}
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static void test_steal(bool do_steal)
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{
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struct test_context c;
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pthread_t contender;
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void *status = NULL;
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int gfd, sfd, ret;
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char *name;
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name = get_unique_name(EVL_MONITOR_DEV, 0);
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__Tcall_assert(gfd, evl_new_mutex(&c.lock, name));
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name = get_unique_name(EVL_MONITOR_DEV, 1);
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__Tcall_assert(sfd, evl_new_sem(&c.start, name));
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c.acquired = false;
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new_thread(&contender, SCHED_FIFO, LOW_PRIO, victim, &c);
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__Tcall_assert(ret, evl_lock_mutex(&c.lock));
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__Tcall_assert(ret, evl_put_sem(&c.start));
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/*
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* Wait for the victim to block on the lock. Sleep for 200ms
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* (for slow VMs)
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*/
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evl_usleep(200000);
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/*
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* Pass the lock ownership to the victim, but we have higher
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* priority so it can't resume just yet. If @do_steal is true,
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* we should be able to steal the lock from it.
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*/
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__Tcall_assert(ret, evl_unlock_mutex(&c.lock));
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if (do_steal) {
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__Tcall_assert(ret, evl_lock_mutex(&c.lock)); /* Steal it. */
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__Fexpr_assert(c.acquired);
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} else {
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evl_usleep(200000);
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__Tcall_assert(ret, evl_lock_mutex(&c.lock));
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__Texpr_assert(c.acquired);
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}
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__Tcall_assert(ret, evl_unlock_mutex(&c.lock));
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__Texpr_assert(pthread_join(contender, &status) == 0);
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__Texpr_assert(status == NULL);
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evl_close_sem(&c.start);
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evl_close_mutex(&c.lock);
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}
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int main(int argc, char *argv[])
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{
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struct sched_param param;
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int tfd;
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param.sched_priority = HIGH_PRIO;
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__Texpr_assert(pthread_setschedparam(pthread_self(),
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SCHED_FIFO, ¶m) == 0);
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__Tcall_assert(tfd, evl_attach_self("monitor-steal:%d", getpid()));
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test_steal(true);
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test_steal(false);
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return 0;
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}
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