release/src/router/busybox/loginutils/vlock.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * vlock implementation for busybox
   4  *
   5  * Copyright (C) 2000 by spoon <spoon@ix.netcom.com>
   6  * Written by spoon <spon@ix.netcom.com>
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9  */
  10
  11 /* Shoutz to Michael K. Johnson <johnsonm@redhat.com>, author of the
  12  * original vlock.  I snagged a bunch of his code to write this
  13  * minimalistic vlock.
  14  */
  15 /* Fixed by Erik Andersen to do passwords the tinylogin way...
  16  * It now works with md5, sha1, etc passwords. */
  17
  18 //usage:#define vlock_trivial_usage
  19 //usage:       "[-a]"
  20 //usage:#define vlock_full_usage "\n\n"
  21 //usage:       "Lock a virtual terminal. A password is required to unlock.\n"
  22 //usage:     "\n        -a      Lock all VTs"
  23
  24 #include "libbb.h"
  25
  26 #ifdef __linux__
  27 #include <sys/vt.h>
  28
  29 static void release_vt(int signo UNUSED_PARAM)
  30 {
  31         /* If -a, param is 0, which means:
  32          * "no, kernel, we don't allow console switch away from us!" */
  33         ioctl(STDIN_FILENO, VT_RELDISP, (unsigned long) !option_mask32);
  34 }
  35
  36 static void acquire_vt(int signo UNUSED_PARAM)
  37 {
  38         /* ACK to kernel that switch to console is successful */
  39         ioctl(STDIN_FILENO, VT_RELDISP, VT_ACKACQ);
  40 }
  41 #endif
  42
  43 int vlock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  44 int vlock_main(int argc UNUSED_PARAM, char **argv)
  45 {
  46 #ifdef __linux__
  47         struct vt_mode vtm;
  48         struct vt_mode ovtm;
  49 #endif
  50         struct termios term;
  51         struct termios oterm;
  52         struct passwd *pw;
  53
  54         pw = xgetpwuid(getuid());
  55         opt_complementary = "=0"; /* no params! */
  56         getopt32(argv, "a");
  57
  58         /* Ignore some signals so that we don't get killed by them */
  59         bb_signals(0
  60                 + (1 << SIGTSTP)
  61                 + (1 << SIGTTIN)
  62                 + (1 << SIGTTOU)
  63                 + (1 << SIGHUP )
  64                 + (1 << SIGCHLD) /* paranoia :) */
  65                 + (1 << SIGQUIT)
  66                 + (1 << SIGINT )
  67                 , SIG_IGN);
  68
  69 #ifdef __linux__
  70         /* We will use SIGUSRx for console switch control: */
  71         /* 1: set handlers */
  72         signal_SA_RESTART_empty_mask(SIGUSR1, release_vt);
  73         signal_SA_RESTART_empty_mask(SIGUSR2, acquire_vt);
  74         /* 2: unmask them */
  75         sig_unblock(SIGUSR1);
  76         sig_unblock(SIGUSR2);
  77 #endif
  78
  79         /* Revert stdin/out to our controlling tty
  80          * (or die if we have none) */
  81         xmove_fd(xopen(CURRENT_TTY, O_RDWR), STDIN_FILENO);
  82         xdup2(STDIN_FILENO, STDOUT_FILENO);
  83
  84 #ifdef __linux__
  85         xioctl(STDIN_FILENO, VT_GETMODE, &vtm);
  86         ovtm = vtm;
  87         /* "console switches are controlled by us, not kernel!" */
  88         vtm.mode = VT_PROCESS;
  89         vtm.relsig = SIGUSR1;
  90         vtm.acqsig = SIGUSR2;
  91         ioctl(STDIN_FILENO, VT_SETMODE, &vtm);
  92 #endif
  93
  94         tcgetattr(STDIN_FILENO, &oterm);
  95         term = oterm;
  96         term.c_iflag &= ~BRKINT;
  97         term.c_iflag |= IGNBRK;
  98         term.c_lflag &= ~ISIG;
  99         term.c_lflag &= ~(ECHO | ECHOCTL);
 100         tcsetattr_stdin_TCSANOW(&term);
 101
 102         while (1) {
 103                 printf("Virtual console%s locked by %s.\n",
 104                                 /* "s" if -a, else "": */ "s" + !option_mask32,
 105                                 pw->pw_name
 106                 );
 107                 if (correct_password(pw)) {
 108                         break;
 109                 }
 110                 bb_do_delay(LOGIN_FAIL_DELAY);
 111                 puts("Incorrect password");
 112         }
 113
 114 #ifdef __linux__
 115         ioctl(STDIN_FILENO, VT_SETMODE, &ovtm);
 116 #endif
 117         tcsetattr_stdin_TCSANOW(&oterm);
 118         fflush_stdout_and_exit(EXIT_SUCCESS);
 119 }