Updated: SEPTEMBER 2009
is a setgid binary,
which provides a reliable way to put an exclusive lock
in /var/lock to devices (e.g. ttyS0) using both FSSTND and SVr4 methods,
so regular users don't need write access there.
This task is achieved through calls to the liblockdev(3) API.
command can perform one of the following operations (calls to liblockdev
-l - lock device with dev_lock() function
-u - unlock device with dev_unlock() function
no operation - test lock with dev_testlock() function
Value dev_lock dev_unlock dev_testlock
0 OK OK not locked
1 locked other locked other locked
255 error error error