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dateshift.o - Kernel module for system time shifting
Introduction
Are you tired from changing system date every time you want to run some trial
applications for more time, or just want to install an old demo program? Or do you
code your new super-system and want to test it with various dates and
times? If so, this module for you. It shifts time to the past or the future from
the current system time for some programms, leaving normal time for all other processes.
The author does not pretend for this idea to be new, - he wrote it for his
own use and fun. All wishes, ideas or patches are welcome. This module should work with all 2.x
kernel versions (although it has not been tested with all of them; also it is completely untested
with the 2.5.x line of kernels ).
How it works
The module overtakes time(3) system call and checks the name of every
process according to /etc/dateshift.conf file. If the name matches, the process
pid is registering in the internal list of processes. Then each time() call is checked in sequence.
If it lies in the required
from-to diapazone, process receives a new (shifted) time (in seconds from the Epoch).
The shift value may be absolute (=), positive (+) or negative (-). By default this
shift is absolute (=). On very busy systems there could be a lot of processes
launched, which require such a shift, so module also takes care of exit(3) system call, when
per-process memory structure is freed. In such way module tries not to use much
of kernel memory. ("Freeing" in the module means using memory reusably).
Installation
- Download this tarball: dateshift-0.98.tar.gz
- Unzip and untar it to your source directory (e.g. /usr/src)
- Type 'make' to get loadable (with 'insmod') dateshift.o kernel module
Disclaimer (non-std)
Author does not take any responsibility for using module for illegal
actions (and no responsibility for everything else).
License
This module was born with GPL license, because it uses the Linux kernel structures
Author
Vladas Saulis
vladas@prodata.lt
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Lithuanian
