[Lldb-commits] [lldb] Fix a bug with cancelling "attach -w" after you have run a process previously (PR #65822)

[via lldb-commits]

jimingham wrote:

The way interruption works in lldb is that the first time you dispatch an interrupt, it just raises the "voluntary interrupt" flag.  Turns out the process attach part of lldb isn't written in a way that makes checking for the interrupt flag possible, so that doesn't work.  The second time you issue the interrupt, since we've already raised the Debugger interrupt flag, we send the Process level interrupt to any running processes.  That's the one that actually interrupts the attach attempt.

This is a variant of the scheme gdb used (at least back in the day), where the first ^C tries to interrupt the current command, and the second ^C tries to interrupt the process connection.  In gdb, on the second ^C you would get a prompt "I see you pressed ^C twice, did you really want to interrupt the process".  I didn't emulate that part as in my usage I pretty much never answered "no" to this question...

Jim


> On Sep 20, 2023, at 2:16 AM, David Spickett ***@***.***> wrote:
> 
> 
> @DavidSpickett commented on this pull request.
> 
> In lldb/test/API/commands/process/attach/TestProcessAttach.py <https://github.com/llvm/llvm-project/pull/65822#discussion_r1331325797>:
> 
> > +        # No need to track the output
> +        self.stdout_path = self.getBuildArtifact("stdout.txt")
> +        self.out_filehandle = open(self.stdout_path, "w")
> +        self.dbg.SetOutputFileHandle(self.out_filehandle, False)
> +        self.dbg.SetErrorFileHandle(self.out_filehandle, False)
> +
> +        n_errors, quit_req, crashed = self.dbg.RunCommandInterpreter(
> +            True, True, options, 0, False, False)
> +        
> +        while 1:
> +            time.sleep(1)
> +            if target.process.state == lldb.eStateAttaching:
> +                break
> +
> +        self.dbg.DispatchInputInterrupt()
> +        self.dbg.DispatchInputInterrupt()
> Why is this done twice?
> 
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https://github.com/llvm/llvm-project/pull/65822