src/examples/cp.c

   1 /* cat.c
   2
   3 Copies one file to another. */
   4
   5 #include <stdio.h>
   6 #include <syscall.h>
   7
   8 int
   9 main (int argc, char *argv[])
  10 {
  11   int in_fd, out_fd;
  12
  13   if (argc != 3)
  14     {
  15       printf ("usage: cp OLD NEW\n");
  16       return 1;
  17     }
  18
  19   /* Open input file. */
  20   in_fd = open (argv[1]);
  21   if (in_fd < 0)
  22     {
  23       printf ("%s: open failed\n", argv[1]);
  24       return 1;
  25     }
  26
  27   /* Create and open output file. */
  28   if (!create (argv[2], filesize (in_fd)))
  29     {
  30       printf ("%s: create failed\n", argv[2]);
  31       return 1;
  32     }
  33   out_fd = open (argv[2]);
  34   if (out_fd < 0)
  35     {
  36       printf ("%s: open failed\n", argv[2]);
  37       return 1;
  38     }
  39
  40   /* Copy data. */
  41   for (;;)
  42     {
  43       char buffer[1024];
  44       int bytes_read = read (in_fd, buffer, sizeof buffer);
  45       if (bytes_read == 0)
  46         break;
  47       if (write (out_fd, buffer, bytes_read) != bytes_read)
  48         {
  49           printf ("%s: write failed\n", argv[2]);
  50           return 1;
  51         }
  52     }
  53
  54   return 0;
  55 }