56 lines
1 KiB
C
56 lines
1 KiB
C
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/* cat.c
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Copies one file to another. */
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#include <stdio.h>
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#include <syscall.h>
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int
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main (int argc, char *argv[])
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{
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int in_fd, out_fd;
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if (argc != 3)
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{
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printf ("usage: cp OLD NEW\n");
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return EXIT_FAILURE;
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}
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/* Open input file. */
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in_fd = open (argv[1]);
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if (in_fd < 0)
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{
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printf ("%s: open failed\n", argv[1]);
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return EXIT_FAILURE;
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}
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/* Create and open output file. */
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if (!create (argv[2], filesize (in_fd)))
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{
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printf ("%s: create failed\n", argv[2]);
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return EXIT_FAILURE;
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}
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out_fd = open (argv[2]);
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if (out_fd < 0)
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{
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printf ("%s: open failed\n", argv[2]);
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return EXIT_FAILURE;
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}
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/* Copy data. */
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for (;;)
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{
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char buffer[1024];
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int bytes_read = read (in_fd, buffer, sizeof buffer);
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if (bytes_read == 0)
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break;
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if (write (out_fd, buffer, bytes_read) != bytes_read)
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{
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printf ("%s: write failed\n", argv[2]);
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return EXIT_FAILURE;
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}
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}
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return EXIT_SUCCESS;
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}
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