79 lines
1.3 KiB
C
79 lines
1.3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <pthread.h>
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#include "common.h"
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#include "common_threads.h"
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typedef struct {
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int num_loops;
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int thread_id;
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} arg_t;
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sem_t forks[5];
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int left(int p) {
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return p;
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}
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int right(int p) {
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return (p + 1) % 5;
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}
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void get_forks(int p) {
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Sem_wait(&forks[left(p)]);
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Sem_wait(&forks[right(p)]);
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}
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void put_forks(int p) {
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Sem_post(&forks[left(p)]);
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Sem_post(&forks[right(p)]);
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}
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void think() {
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return;
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}
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void eat() {
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return;
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}
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void *philosopher(void *arg) {
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arg_t *args = (arg_t *) arg;
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int i;
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for (i = 0; i < args->num_loops; i++) {
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think();
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get_forks(args->thread_id);
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eat();
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put_forks(args->thread_id);
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}
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return NULL;
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}
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int main(int argc, char *argv[]) {
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if (argc != 2) {
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fprintf(stderr, "usage: dining_philosophers_deadlock <num_loops>\n");
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exit(1);
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}
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printf("dining: started\n");
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int i;
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for (i = 0; i < 5; i++)
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Sem_init(&forks[i], 1);
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pthread_t p[5];
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arg_t a[5];
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for (i = 0; i < 5; i++) {
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a[i].num_loops = atoi(argv[1]);
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a[i].thread_id = i;
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Pthread_create(&p[i], NULL, philosopher, &a[i]);
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}
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for (i = 0; i < 5; i++)
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Pthread_join(p[i], NULL);
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printf("dining: finished\n");
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return 0;
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}
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