> Ok, this gives us a definite proposal, which I finally like: > > * to exclude sys_tee: > > bitmask = 0; > set_bit(__NR_tee, bitmask); > ptrace(PTRACE_SET_NOTRACE, bitmask); > > * to trace only sys_tee: > > bitmask = 0; > set_bit(__NR_tee, bitmask); > ptrace(PTRACE_SET_TRACEONLY, bitmask); > > Semantics: > > in both cases, the mask is first zero-extended to the right (for syscalls not > known to userspace), bits for syscall not known to the kernel are checked and > the call fails if any of them is 1, and in the failure case E2BIG or > EOVERFLOW is returned (I want to avoid EINVAL and ENOSYS to avoid confusion) > and the part of the mask known to the kernel is 0-ed. > > In case of success, for NOTRACE (which was DEFAULT_TRACE) the mask is > reversed > before copying in the kernel syscall mask, for TRACEONLY it's copied there > directly.
IMHO this is way too complicated. Introducing a ptrace call that returns the number of syscalls and forcing user space to pass a complete bitmask is much easier. Also the semantics are much easier to understand. In addition your proposal would already introduce a rather complicated interface to figure out how many syscalls the kernel has. I'm sure this will be (mis)used sooner or later. ------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
