91 lines
1.6 KiB
C
91 lines
1.6 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <signal.h>
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#include <assert.h>
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void filter(int p)
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{
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while (1)
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{
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int n;
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ssize_t nb_read = read(0, &n, sizeof(int));
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if (nb_read <= 0)
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break;
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if ((n % p) != 0)
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write(1, &n, sizeof(int));
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}
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}
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void seq(int n)
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{
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for (int i = 2; i <= n; i++)
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write(1, &i, sizeof(int));
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}
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void chef(void)
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{
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while (1)
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{
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int p;
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pid_t f;
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int t[2];
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ssize_t nb_read = read(0, &p, sizeof(int));
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if (nb_read <= 0)
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break;
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printf("new prime %d\n", p);
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pipe(t);
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f = fork();
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if (f == 0)
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{
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close(t[0]);
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dup2(t[1], 1);
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close(t[1]);
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filter(p);
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exit(0);
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}
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close(t[1]);
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dup2(t[0], 0);
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close(t[0]);
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}
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}
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int main(int argc, char *argv[])
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{
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if (argc < 2)
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{
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printf("Usage: %s <N>\n", argv[0]);
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return EXIT_FAILURE;
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}
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struct sigaction sa = {0};
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_NOCLDWAIT;
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sigaction(SIGCHLD, &sa, NULL);
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int t[2];
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int N = strtol(argv[1], NULL, 0);
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pipe(t);
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pid_t p = fork();
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assert(p != -1);
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if (p == 0)
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{
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close(t[0]);
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dup2(t[1], 1);
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close(t[1]);
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seq(N);
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exit(0);
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}
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close(t[1]);
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dup2(t[0], 0);
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close(t[0]);
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chef();
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return 0;
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} |