primes.c

td/td5/primes.c

@@ -0,0 +1,85 @@
+#include <math.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <sys/wait.h>
+
+void filter(int p)
+{
+	while(1){
+		int n;
+		ssize_t nb_read = read(STDIN_FILENO,&n,sizeof(int));
+		if (nb_read <= 0)
+			break;
+		if ((n%p) !=0)
+			write(STDOUT_FILENO,&n,sizeof(int));
+	}
+	exit(0);
+}
+
+void seq(int N)
+{
+	for(int i = 2;i <= N; i++)
+		write(STDOUT_FILENO,&i,sizeof(i));
+	exit(0);
+}
+
+int master()
+{
+	int count_primes = 0;
+	while(1){
+		ssize_t nb_read;
+		pid_t p;
+		int t[2];
+		int prime;
+		nb_read = read(STDIN_FILENO,&prime,sizeof(int));
+		if (nb_read <=0)
+			break;
+		printf("prime = %d\n",prime);
+		count_primes  ++;
+		assert(pipe(t) == 0);
+		p = fork();
+		if (p == 0){
+			close(t[0]);
+			dup2(t[1],STDOUT_FILENO);
+			close(t[1]);
+			filter(prime);
+
+		}
+		close(t[1]);
+		dup2(t[0],STDIN_FILENO);
+		close(t[0]);
+
+	}
+	return count_primes;
+}
+
+int main(int argc, char *argv[])
+{
+	int t[2];
+	pid_t p;
+	struct sigaction sa = {0};
+
+	int max = (int)strtol(argv[1],NULL,0);
+	sa.sa_flags = SA_NOCLDWAIT;
+	sigemptyset(&sa.sa_mask);
+
+	sigaction(SIGCHLD, &sa , NULL);
+	assert(pipe(t) == 0);
+
+	p = fork();
+
+	if (p == 0){
+		close(t[0]);
+		dup2(t[1],STDOUT_FILENO);
+		close(t[1]);
+		seq(max);
+	}
+	close(t[1]);
+	dup2(t[0],STDIN_FILENO);
+	close(t[0]);
+	printf("densité = %lf\n",master()*1.0/max);
+	return 0;
+}