ptrace task state logic cleanup

ptrace task state logic cleanup

[Mark Wielaard]

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Hi Mike,

Yesterday evening on irc we discussed some troubles with Instruction
observers for newly started processes. Going over the ptrace task state
machine for my breakpoint stepping work I cleaned up the logic a little
to have all state transitions into any Running state go through the same
Running.sendContinue() method removing a couple corner cases where the
first continue of a Task might miss the step or signal continue.
LinuxTaskState now also explicitly checks the syscall observers
installed instead of keeping its own state which might (theoretically, I
haven't actually seen this happen) get out of sync, which simplifies the
logic a lot.

This might not actually fix your issue since if I understood correctly
it was that the Task wasn't getting out of the blocked state and none of
the logic changes with respect to that. But the code should be more
clean and consistent which might help tracking down the issue.

Cheers,

Mark

2007-06-19  Mark Wielaard  <mwielaard@redhat.com

    * LinuxTaskState.java (clonedState): No more syscallRunning and
    inSyscallRunningTraced.
    (transitionToRunningState): Use Running.sendContinue() return value.
    (attemptContinue): Likewise.
    (blockedOffspring.handleUnblock): Likewise.
    (Running.syscalltracing): Removed.
    (Running): Removed syscalltracing argument.
    (sendContinue): Return new state. Check number of syscallObservers.
    (handleSignaledEvent): Return sendContinue value.
    (handleStoppedEvent(: Likewise.
    (handleTerminatingEvent): Likewise.
    (handleExecedEvent): Simplify logic, don't check observer, but use
    sendContinue.
    (handleClonedEvent): Return sendContinue value.
    (handleForkedEvent): Likewise.
    (handleTrappedEvent): Likewise.
    (handleSyscalledEvent): Check number of syscallObservers and return
    sendContinue value.
    (syscallRunning): Removed.
    (inSyscallRunningTraced): Removed.
    (BlockedSignal.handleUnblock): Return sendContinue value.


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