commands/tee/tee.c

   1 /* tee - pipe fitting                   Author: Paul Polderman */
   2
   3 #include <sys/types.h>
   4 #include <fcntl.h>
   5 #include <signal.h>
   6 #include <unistd.h>
   7 #include <stdlib.h>
   8 #include <minix/minlib.h>
   9
  10 #define MAXFD   18
  11 #define CHUNK_SIZE      4096
  12
  13 int fd[MAXFD];
  14
  15 int main(int argc, char **argv);
  16
  17 int main(argc, argv)
  18 int argc;
  19 char **argv;
  20 {
  21   char iflag = 0, aflag = 0;
  22   char buf[CHUNK_SIZE];
  23   int i, s, n;
  24
  25   argv++;
  26   --argc;
  27   while (argc > 0 && argv[0][0] == '-') {
  28         switch (argv[0][1]) {
  29             case 'i':           /* Interrupt turned off. */
  30                 iflag++;
  31                 break;
  32             case 'a':           /* Append to outputfile(s), instead of
  33                          * overwriting them. */
  34                 aflag++;
  35                 break;
  36             default:
  37                 std_err("Usage: tee [-i] [-a] [files].\n");
  38                 exit(1);
  39         }
  40         argv++;
  41         --argc;
  42   }
  43   fd[0] = 1;                    /* Always output to stdout. */
  44   for (s = 1; s < MAXFD && argc > 0; --argc, argv++, s++) {
  45         if (aflag && (fd[s] = open(*argv, O_RDWR)) >= 0) {
  46                 lseek(fd[s], 0L, SEEK_END);
  47                 continue;
  48         } else {
  49                 if ((fd[s] = creat(*argv, 0666)) >= 0) continue;
  50         }
  51         std_err("Cannot open output file: ");
  52         std_err(*argv);
  53         std_err("\n");
  54         exit(2);
  55   }
  56
  57   if (iflag) signal(SIGINT, SIG_IGN);
  58
  59   while ((n = read(0, buf, CHUNK_SIZE)) > 0) {
  60         for (i = 0; i < s; i++) write(fd[i], buf, n);
  61   }
  62
  63   for (i = 0; i < s; i++)       /* Close all fd's */
  64         close(fd[i]);
  65   return(0);
  66 }