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I am designing an application that is using HAM to monitor other processes
on the system. This application must also monitor itself so that if it
terminates due to a fault, it restarts itself. The basic design is as
follows

1. application on startup forks and attached to HAM
2. parent monitors other processes
3. child monitor parent
4. if parent fails, child repeat step 1-3.

I know i have to use fork. what I want suggestions on is how to go about
step 4 when the parent dies. That is when HAM informs the child that the
parent is dead, how to proceed with reforking and restarting the entire
process again. Can I somehow make a recursive call??

I am designing an application that is using HAM to monitor other processes
on the system. This application must also monitor itself so that if it
terminates due to a fault, it restarts itself. The basic design is as
follows

1. application on startup forks and attached to HAM
2. parent monitors other processes
3. child monitor parent
4. if parent fails, child repeat step 1-3.

I know i have to use fork. what I want suggestions on is how to go about
step 4 when the parent dies. That is when HAM informs the child that the
parent is dead, how to proceed with reforking and restarting the entire
process again. Can I somehow make a recursive call??

I think you just need a loop, something like this.

Loop
Fork, Parent monitors 4 processes, child monitors parent (Actually
I think it might be easier the other way around
Wait for parent to die
End Loop

You might want to be careful that you don't fork too often. If
something crucial prevents either the fork from working, or
the forked process from running, you don't want continual calls to
fork. This can really hose up a system that is already
sick.

Sometimes we've used a shellscript with an infinite loop (while true ...)
Inside the loop you can call your program
While your program is active the infinite loop is waiting for the end of
the
launched program
If your program dies the loop will execute next iteration restarting your
program.
You can add an sleep in the loop to prevent collapsing system if the
program
fails continously

To stop your program you have to first stop the shellscript with the
infinite
loop (We use kill command to do that)

sabtain wrote:

I am designing an application that is using HAM to monitor other
processes
on the system. This application must also monitor itself so that if it
terminates due to a fault, it restarts itself. The basic design is as
follows

1. application on startup forks and attached to HAM
2. parent monitors other processes
3. child monitor parent
4. if parent fails, child repeat step 1-3.

I know i have to use fork. what I want suggestions on is how to go about
step 4 when the parent dies. That is when HAM informs the child that the
parent is dead, how to proceed with reforking and restarting the entire
process again. Can I somehow make a recursive call??