69 lines
1.4 KiB
C
69 lines
1.4 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include <sys/wait.h>
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int
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main (int argc, char **argv)
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{
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int fd, pid, n;
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int fds[2];
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static char buf[4096];
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close (0);
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if ((fd = open ("/dev/null", O_WRONLY)) != 0)
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{
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fprintf (stderr, "couldn't redirect stdin to /dev/null, fd %d - %s\n", fd, strerror (errno));
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exit (1);
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}
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close (1);
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if ((fd = open ("/dev/null", O_WRONLY)) != 1)
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{
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fprintf (stderr, "couldn't redirect stdout to /dev/null, fd %d - %s\n", fd, strerror (errno));
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exit (1);
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}
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if (pipe (fds))
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{
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fprintf (stderr, "pipe call failed - %s\n", strerror (errno));
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exit (1);
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}
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if ((pid = fork ()) == 0)
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{
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close (fds[0]);
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if (dup2 (fds[1], 2) != 2)
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{
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fprintf (stderr, "couldn't redirect stderr to pipe - %s\n", strerror (errno));
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exit (1);
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}
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exit (system ("ls"));
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}
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else if (pid < 0)
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{
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perror ("couldn't fork");
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exit (1);
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}
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close (fds[1]);
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if (read (fds[0], buf, 4096) != 0)
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{
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fprintf (stderr, "system() call failed?\n%s\n", buf);
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exit (1);
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}
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if (waitpid (pid, &n, 0) < 0)
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{
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perror ("waitpid failed");
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exit (1);
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}
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if (n != 0)
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{
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fprintf (stderr, "system() call returned %p\n", (void *) n);
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exit (1);
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}
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exit (0);
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}
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