gdbstub initial code, v7

[Roland McGrath]

> Currently GDB does not do anything special, that is if there is siginfo for
> signal SIGUSR1 but one does $C0B (SIGSEGV) does ptrace reset the siginfo or is
> left the SIGUSR1 siginfo for SIGSEGV?

The kernel considers this sloppy behavior on the debugger's part.  If
you inject a different signal, we expect you should PTRACE_SETSIGINFO
to something appropriate, or else that you really didn't care about
the bits being accurate.  If the resumption signal does not match the
siginfo_t.si_signo, then the kernel resets the siginfo as if the
debugger had just used kill with the new signal (i.e. si_pid, si_uid
point to the ptracer).


Thanks,
Roland