util/post/post.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  */
  12
  13 #include <errno.h>
  14 #include <limits.h>
  15 #include <stdarg.h>
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <sys/io.h>
  19
  20 #define POST_DEFAULT_IO_PORT 0x80
  21
  22 void usage(char *progname, const char *error, ...)
  23 {
  24         printf("Usage: %s <VALUE> [PORT]\n", progname);
  25         printf("The VALUE argument is an integer between 0x00 and 0xff\n");
  26         printf("The PORT argument is an integer between 0x00 and 0xffff\n");
  27
  28         if (error) {
  29                 va_list args;
  30
  31                 va_start(args, error);
  32                 vprintf(error, args);
  33                 va_end(args);
  34         };
  35 }
  36
  37 void check_int(long val, int min, int max, int err, char *string, char *endptr,
  38                char *progname)
  39 {
  40         if (val < min || val > max) {
  41                 usage(progname,
  42                       "\nError: The value has to be between 0x%x and 0x%x\n",
  43                       min, max);
  44                 exit(EXIT_FAILURE);
  45         }
  46
  47         if (endptr == string || *endptr != '\0') {
  48                 usage(progname, "\nError: An integer is required\n");
  49                 exit(EXIT_FAILURE);
  50         }
  51
  52         if ((err) && (!val)) {
  53                 perror("strtol");
  54                 exit(EXIT_FAILURE);
  55         }
  56 }
  57
  58 int main(int argc, char *argv[])
  59 {
  60         unsigned long val;
  61         unsigned long port = POST_DEFAULT_IO_PORT;
  62         char *endptr;
  63         int err;
  64
  65         if (argc != 2 && argc != 3) {
  66                 usage(argv[0], NULL);
  67                 exit(EXIT_FAILURE);
  68         }
  69
  70         val = strtol(argv[1], &endptr, 0);
  71         err = errno;
  72         check_int(val, 0x00, 0xff, err, argv[1], endptr, argv[0]);
  73
  74         if (argc > 2) {
  75                 port = strtol(argv[2], &endptr, 0);
  76                 err = errno;
  77                 check_int(port, 0x0000, 0xffff, err, argv[2], endptr, argv[0]);
  78         }
  79
  80         err = iopl(3);
  81         if (err == -1) {
  82                 perror("Not root");
  83                 exit(EXIT_FAILURE);
  84         }
  85
  86         outb(val, port);
  87
  88         return 0;
  89 }