VLOCK(1) | Linux User's Manual | VLOCK(1) |
vlock - Virtual Console lock program
vlock [ -hv ]
vlock [ -acns ] [ -t <timeout> ] [ plugins... ]
vlock is a program to lock one or more sessions on the Linux console. This is especially useful for Linux machines which have multiple users with access to the console. One user may lock his or her session(s) while still allowing other users to use the system on other virtual consoles. If desired, the entire console may be locked and virtual console switching disabled.
By default, only the current VC (virtual console) is locked. With the -a,--all option all VCs are locked. The locked VCs cannot be unlocked without the invoker's password or the root password. The root password will always be able to unlock any or all sessions, unless disabled at compile time.
Please note that it is entirely possible to completely lock yourself out of the console with the -a,--all option if you cannot remember your password! Unless you are able to kill vlock by logging in remotely via a serial terminal or network, a hard reset is the only method of ``unlocking'' the display.
When locking the entire console display it is sometimes still possible to kill vlock using the Secure Access Key (SAK) or other commands that are available through the SysRq mechanism. When the -s,--disable-sysrq and -a,--all options are given the SysRq mechanism is disabled while vlock is running. See /usr/src/linux/Documentation/sysrq.txt for more details.
vlock works for console sessions primarily. To lock the entire console display from an X session use the -n,--new option. This will make vlock switch to an empty virtual console to lock the display.
The options -n,--new, -s,--disable-sysrq, and -t,--timeout only work if vlock is compiled with plugin support. See the PLUGINS section for more information.
-a,--all
-c,--current
-n,--new
-s,--disable-sysrq
-t,--timeout <seconds>
-h,--help
-v,--version
The following environment variables can be used to change vlock's behavior:
USER
VLOCK_ALL_MESSAGE
VLOCK_CURRENT_MESSAGE
VLOCK_MESSAGE
VLOCK_PLUGINS
VLOCK_TIMEOUT
VLOCK_PROMPT_TIMEOUT
~/.vlockrc
See the SECURITY file in the vlock distribution for more information.
Michael K. Johnson <http://danlj.org/mkj/>
Frank Benkstein <frank-vlock@benkstein.net>
28 July 2007 | Linux |