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    SubjectRe: [RFC] [Patch 1/1] [Self Ptrace] System call notification with self_ptrace
    Hi,

    Dave Hansen wrote:
    > On Mon, 2008-08-25 at 09:34 +0200, Pierre Morel wrote:
    >
    >> + if ((current->ptrace & PT_SELF)
    >> + && (regs->orig_ax != __NR_rt_sigreturn)
    >> + && (regs->orig_ax != __NR_ptrace)) {
    >> + if (!entryexit) {
    >> + struct siginfo info;
    >> +
    >> + memset(&info, 0, sizeof(struct siginfo));
    >> + info.si_signo = SIGSYS;
    >> + info.si_code = SYS_SYSCALL;
    >> + info.si_addr = (void *) regs->orig_ax;
    >> + send_sig_info(SIGSYS, &info, current);
    >> + }
    >> + return 1; /* Skip system call, deliver signal. */
    >> + }
    >>
    >
    > The indenting here looks messed up.
    >
    You are right, I will rework the patch and send it again, it has a lot of
    formating errors indeed.
    > Also, there looks to be a pretty substantial amount of copy-and-paste
    > code in those little if()s. It's only going to get worse as we add more
    > architectures. If there's ever a little buglet in that bit of code, or
    > we need to tweak it it some way, it'll be a bitch to fix.
    >
    > For instance, if you have a little arch-independent helper like this:
    >
    > static inline int is_self_ptracing(unsigned long syscall_reg)
    > {
    > if (!(current->ptrace & PT_SELF))
    > return 0;
    > if (syscall_reg == __NR_rt_sigreturn)
    > return 0;
    > if (syscall_reg == __NR_ptrace)
    > return 0;
    > return 1;
    > }
    >
    > You can call it like this:
    >
    > if (is_self_ptracing(regs->gprs[2]))
    > ...
    > if (is_self_ptracing(regs->orig_ax))
    > ...
    > if (is_self_ptracing(regs->orig_rax))
    >
    > Something similar can probably be done for the siginfo construction.
    >
    Yes, thank you it is a good tip.
    > You should basically try and think of ways to abstract this stuff every
    > single time you touch arch code.
    >
    > Why don't you also mention why you really want this feature. That's
    > missing from the description.
    >
    Yes, you are right too, I will rework the patch description too.
    > -- Dave
    >
    >
    Thanks for the comments, I rework the patch.

    Pierre

    --
    =============
    Pierre Morel
    RTOS and Embedded Linux



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