On Wednesday 14 September 2005 13:48, Bodo Stroesser wrote: > Bodo Stroesser wrote: > > OTOH, if the new API would reuse the same ptrace code, check_sysemu of > > the old > > binaries will fail on i386
> > (and I hope on x86_64, too). Nobody implemented sysemu for x86_64, at least to my knowledge. I hoped to finish skas first, but stopped on that problem. > > That means, > > sysemu again > > will be disabled. AFAICS, it will not refuse to run at all. (Not tested, > > taken from > > the code only) > > On s390 the check even might succeed accidentally, but that's no > > problem, as s390 > > isn't mainline yet, we can change check_sysemu() to avoid problems. > > There will > > never be an old binary for s390. > Some more points: > The new API must have PTRACE_SYSEMU _and_ PTRACE_SYSEMU_SINGLESTEP. Granted. > While with the old API SYSEMU_SINGLESTEP was inserted to improve security, > with the new one it will be necessary to allow singlestepping of processes > in UML-SKAS at all. Suppose a singlestepped userspace is stopped at a > syscall interception. Now UML needs to restart it with SYSEMU for syscall > emulation, but also wants to proceed with singlestepping. PTRACE_SYSEMU > wouldn't do the job, as it starts userspace in "normal" mode, no > singlestepping. Hmm, I hadn't looked at this detail... > Also, in tt new API's PTRACE_SYSEMU behaves as PTRACE_SYSCALL does, because > tracer uses PTRACE_CONT after syscall interception. So tt (do_syscall(), > ...) needs to be changed. PTRACE_SYSEMU_SINGLESTEP still should be used, as > if it's name were PTRACE_SYSCALL_SINGLESTEP. Ok, I think it's enough to warrant keeping the current behaviour and adding later an option, and/or removing it for now and merging it later. Unless somebody manages to fix all this in time. I don't think I'm likely to accomplish this, sorry. > Bodo -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade ___________________________________ Yahoo! Mail: gratis 1GB per i messaggi e allegati da 10MB http://mail.yahoo.it ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ User-mode-linux-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
