blob: 44b14e6bc460387c0e6ec23ed7714808e6934c3a
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 (ask_and_check_password(pw) > 0) { |
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 | } |
120 |