80 lines
1.5 KiB
C
80 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#include <errno.h>
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#include <limits.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/io.h>
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#define POST_DEFAULT_IO_PORT 0x80
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void usage(char *progname, const char *error, ...)
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{
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printf("Usage: %s <VALUE> [PORT]\n", progname);
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printf("The VALUE argument is an integer between 0x00 and 0xff\n");
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printf("The PORT argument is an integer between 0x00 and 0xffff\n");
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if (error) {
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va_list args;
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va_start(args, error);
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vprintf(error, args);
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va_end(args);
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};
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}
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void check_int(long val, int min, int max, int err, char *string, char *endptr,
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char *progname)
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{
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if (val < min || val > max) {
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usage(progname,
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"\nError: The value has to be between 0x%x and 0x%x\n",
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min, max);
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exit(EXIT_FAILURE);
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}
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if (endptr == string || *endptr != '\0') {
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usage(progname, "\nError: An integer is required\n");
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exit(EXIT_FAILURE);
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}
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if ((err) && (!val)) {
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perror("strtol");
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exit(EXIT_FAILURE);
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}
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}
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int main(int argc, char *argv[])
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{
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unsigned long val;
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unsigned long port = POST_DEFAULT_IO_PORT;
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char *endptr;
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int err;
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if (argc != 2 && argc != 3) {
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usage(argv[0], NULL);
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exit(EXIT_FAILURE);
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}
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val = strtol(argv[1], &endptr, 0);
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err = errno;
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check_int(val, 0x00, 0xff, err, argv[1], endptr, argv[0]);
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if (argc > 2) {
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port = strtol(argv[2], &endptr, 0);
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err = errno;
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check_int(port, 0x0000, 0xffff, err, argv[2], endptr, argv[0]);
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}
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err = iopl(3);
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if (err == -1) {
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perror("Not root");
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exit(EXIT_FAILURE);
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}
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outb(val, port);
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return 0;
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}
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