70 lines
1.0 KiB
C
70 lines
1.0 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <assert.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <signal.h>
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int main(int argc, char *argv[])
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{
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pid_t p;
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int fd[2];
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char c;
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if (pipe(fd) == -1)
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{
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exit(1);
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}
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p = fork();
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assert(p != -1);
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int id = 0;
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if (p == 0)
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{
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id += 2;
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}
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p = fork();
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assert(p != -1);
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if (p == 0)
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{
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id += 1;
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}
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if (id == 0)
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{
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wait(NULL);
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wait(NULL);
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}
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if (id == 2)
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{
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wait(NULL);
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}
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while (id == 1)
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{
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int w = write(fd[1], &p, sizeof(pid_t));
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assert(w == sizeof(pid_t));
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printf("%d sent %d\n", p, p);
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sleep(3);
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}
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while (id == 3)
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{
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int op;
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int r = read(fd[0], &op, sizeof(pid_t));
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assert(r == sizeof(pid_t));
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printf("\t%d received %d\n", p, op);
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sleep(1);
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}
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}
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