hal-lock can be used to acquire a lock on a given interface either on a given device or globally. For more information about both the big picture and the semantics of HAL locks, refer to the HAL spec which can be found in /usr/share/doc/hal-doc/spec/hal-spec.html depending on the distribution.
This program will attempt to grab a lock on a given interface. Unless, a specific UDI is given, the global lock will be tried. If the lock was succesfully acquired the program specified by the option --run will be run and upon termination this program will exit with exit code 0. If the lock wasn't acquired or an error occured while taking the lock, this program will exit with a non-zero exit code and the given program will not be run.
This program is only useful for launching software that doesn't use HAL at all (since such software launched using hal-lock would be locked out itself); for example a partition table editor part-foo may use wrapper script like this
hal-lock --interface org.freedesktop.Hal.Device.Storage --exclusive --run /path/to/part-foo-program
Please send bug reports to either the distribution or the HAL mailing list, see http://lists.freedesktop.org/mailman/listinfo/hal on how to subscribe.