35 lines
884 B
C
35 lines
884 B
C
#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <fcntl.h>
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#include <assert.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 rc = fork();
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if (rc < 0) {
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// fork failed; exit
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fprintf(stderr, "fork failed\n");
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exit(1);
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} else if (rc == 0) {
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// child: redirect standard output to a file
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close(STDOUT_FILENO);
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open("./p4.output", O_CREAT|O_WRONLY|O_TRUNC, S_IRWXU);
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// now exec "wc"...
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char *myargs[3];
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myargs[0] = strdup("wc"); // program: "wc" (word count)
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myargs[1] = strdup("p4.c"); // argument: file to count
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myargs[2] = NULL; // marks end of array
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execvp(myargs[0], myargs); // runs word count
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} else {
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// parent goes down this path (original process)
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int wc = wait(NULL);
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assert(wc >= 0);
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}
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return 0;
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}
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