Messages in this thread | | | Date | Mon, 9 Dec 2019 21:46:35 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH v2 4/4] samples: Add example of using PTRACE_GETFD in conjunction with user trap |
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On 12/09, Christian Brauner wrote: > > >We can > >add PTRACE_DETACH_ASYNC, but this makes me think that PTRACE_GETFD has > >nothing > >to do with ptrace. > > > >May be a new syscall which does ptrace_may_access() + get_task_file() > >will make > >more sense? > > > >Oleg. > > Once more since this annoying app uses html by default... > > But we can already do this right now and this is just an improvement. > That's a bit rich for a new syscall imho...
I agree, and I won't really argue...
but the changelog in 2/4 says
The requirement that the tracer has attached to the tracee prior to the capture of the file descriptor may be lifted at a later point.
so may be we should do this right now?
plus this part
@@ -1265,7 +1295,8 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, } ret = ptrace_check_attach(child, request == PTRACE_KILL || - request == PTRACE_INTERRUPT); + request == PTRACE_INTERRUPT || + request == PTRACE_GETFD);
actually means "we do not need ptrace, but we do not know where else we can add this fd_install(get_task_file()).
Oleg.
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