We aim to save the state of a running process including one file that's being accessed by this process. Afterwards, we should be able to restore the state of this process, even after a reboot has beed made. Therefor we experimented and tried different possibilities to get information about running processes in order to freeze them.
Our main program saves and restores the virtual memory area and registers of a programm called writer. It also backups the file that is used by writer and restores also the file.
We experimented with signals like SIGSTOP.
Another possiblity to freeze a process is to force the kernel to swap it. We do this by assigning the process to a cgroup and limit the memory size of this cgroup, so the kernel saves the process on the harddisk.
cgroup - bash script to put a process by its pid into freezer group and freeze the entire group cgroup_freezer does all of this in one step, letting the terminal sleep for a few seconds. You can use the other scripts to do this step by step.
There is the possibilty to only save the current working directory (cwd) and the command line of a process to restart it again later.