sys-utils/ctrlaltdel.c

   1 /*
   2  * SPDX-License-Identifier: GPL-2.0-or-later
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Copyright (C) 1992 Peter Orbaek <poe@daimi.aau.dk>
  10  * Copyright (C) 1992-1993 Rickard E. Faith <faith@cs.unc.edu>
  11  *
  12  * Set the function of the Ctrl-Alt-Del combination
  13  */
  14 #include <getopt.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <errno.h>
  19 #include <unistd.h>
  20 #include <sys/reboot.h>
  21 #include "nls.h"
  22 #include "c.h"
  23 #include "closestream.h"
  24 #include "pathnames.h"
  25 #include "path.h"
  26
  27 #define LINUX_REBOOT_CMD_CAD_ON 0x89ABCDEF
  28 #define LINUX_REBOOT_CMD_CAD_OFF 0x00000000
  29
  30 static void __attribute__((__noreturn__)) usage(void)
  31 {
  32         FILE *out = stdout;
  33         fputs(USAGE_HEADER, out);
  34         fprintf(out, _(" %s hard|soft\n"), program_invocation_short_name);
  35
  36         fputs(USAGE_SEPARATOR, out);
  37         fprintf(out, _("Set the function of the Ctrl-Alt-Del combination.\n"));
  38
  39         fputs(USAGE_OPTIONS, out);
  40         fprintf(out, USAGE_HELP_OPTIONS(16));
  41         fprintf(out, USAGE_MAN_TAIL("ctrlaltdel(8)"));
  42         exit(EXIT_SUCCESS);
  43 }
  44
  45 static int get_cad(void)
  46 {
  47         uint64_t val;
  48
  49         if (ul_path_read_u64(NULL, &val, _PATH_PROC_CTRL_ALT_DEL) != 0)
  50                 err(EXIT_FAILURE, _("cannot read %s"), _PATH_PROC_CTRL_ALT_DEL);
  51
  52         switch (val) {
  53         case 0:
  54                 fputs("soft\n", stdout);
  55                 break;
  56         case 1:
  57                 fputs("hard\n", stdout);
  58                 break;
  59         default:
  60                 printf("%s hard\n", _("implicit"));
  61                 warnx(_("unexpected value in %s: %ju"), _PATH_PROC_CTRL_ALT_DEL, val);
  62                 return EXIT_FAILURE;
  63         }
  64         return EXIT_SUCCESS;
  65 }
  66
  67 static int set_cad(const char *arg)
  68 {
  69         unsigned int cmd;
  70
  71         if (geteuid()) {
  72                 warnx(_("You must be root to set the Ctrl-Alt-Del behavior"));
  73                 return EXIT_FAILURE;
  74         }
  75         if (!strcmp("hard", arg))
  76                 cmd = LINUX_REBOOT_CMD_CAD_ON;
  77         else if (!strcmp("soft", arg))
  78                 cmd = LINUX_REBOOT_CMD_CAD_OFF;
  79         else {
  80                 warnx(_("unknown argument: %s"), arg);
  81                 return EXIT_FAILURE;
  82         }
  83         if (reboot(cmd) < 0) {
  84                 warn("reboot");
  85                 return EXIT_FAILURE;
  86         }
  87         return EXIT_SUCCESS;
  88 }
  89
  90 int main(int argc, char **argv)
  91 {
  92         int ch, ret;
  93         static const struct option longopts[] = {
  94                 {"version", no_argument, NULL, 'V'},
  95                 {"help", no_argument, NULL, 'h'},
  96                 {NULL, 0, NULL, 0}
  97         };
  98
  99         setlocale(LC_ALL, "");
 100         bindtextdomain(PACKAGE, LOCALEDIR);
 101         textdomain(PACKAGE);
 102         close_stdout_atexit();
 103
 104         while ((ch = getopt_long(argc, argv, "Vh", longopts, NULL)) != -1)
 105                 switch (ch) {
 106                 case 'V':
 107                         print_version(EXIT_SUCCESS);
 108                 case 'h':
 109                         usage();
 110                 default:
 111                         errtryhelp(EXIT_FAILURE);
 112                 }
 113
 114         if (argc < 2)
 115                 ret = get_cad();
 116         else
 117                 ret = set_cad(argv[1]);
 118         return ret;
 119 }