40 lines
656 B
C
40 lines
656 B
C
/*
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* This code is identical to running
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* w | wc -w
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* in bash
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*/
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#include <stdio.h>
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#include <unistd.h>
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void child(int pfd[2]) {
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close(pfd[1]);
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dup2(pfd[0], STDIN_FILENO);
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close(pfd[0]);
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char cmd[] = "/usr/bin/wc";
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char *args[] = {"wc", "-w", NULL};
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execve(cmd, args, NULL);
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}
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void parent(int pfd[2]) {
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close(pfd[0]);
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dup2(pfd[1], STDOUT_FILENO);
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close(pfd[1]);
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char cmd[] = "/usr/bin/w";
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char *args[] = {"wc", NULL};
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execve(cmd, args, NULL);
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}
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int main (void) {
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int pfd[2];
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pipe(pfd);
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int pid = fork();
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if (pid == 0) {
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child(pfd);
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} else {
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parent(pfd);
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}
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}
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