On Fri, Nov 19, 2004 at 09:41:44PM +0100, Eric Pouech wrote: > >Btw, does wine ever _use_ PTRACE_SINGLESTEP for any of the things it does? > > > >If it does, then that woulc certainly explain why my "fix" made no > >difference: my fix _only_ handles the case where the ptracer never > >actually asks for single-stepping, and single-stepping was started > >entirely by the program being run (ie by setting TF in eflags from within > >the program itself). > > > >But if wine ends up using PTRACE_SINGESTEP because wine actually wants to > >single-step over some instructions, then the kernel will set the PT_DTRACE > >bit, and start tracing through signal handlers too. The way Wine doesn't > >want.. > > wine mixes both approches, we have (to control what's generated inside the > various exception) to ptrace from our NT-kernel-like process (the ptracer) > to get the context of the exception. Restart from the ptracer is done with > PTRACE_SINGLESTEP.
I'm getting the feeling that the question of whether to step into signal handlers is orthogonal to single-stepping; maybe it should be a separate ptrace operation. Platforms which don't implement PTRACE_SINGLESTEP would probably appreciate this. A "single step" which stops you after setting up the signal trampoline and adjusting the PC, before executing any instructions in the handler. -- Daniel Jacobowitz
