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Re: Dynamically inspecting Regex OP-Codes at runtime?

by Anonymous Monk
on Jan 30, 2013 at 11:37 UTC ( #1016040=note: print w/replies, xml ) Need Help??

in reply to Dynamically inspecting Regex OP-Codes at runtime?

I asked in Rx-0.53/ as a module because I wanted it to simplify YAPE::Regex::Explain -- easier to extend if perl does the tokenizing

I did come accross re::engine::Hooks and Devel::RegExp, but couldn't compile either at the time ... and its all perlreguts to me, but t/re-engine-Hooks-TestDist/TestDist.xs does look promising

  • Comment on Re: Dynamically inspecting Regex OP-Codes at runtime?

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Re^2: Dynamically inspecting Regex OP-Codes at runtime?
by LanX (Chancellor) on Jan 30, 2013 at 11:44 UTC
        Thx for the links but thats Chinese for me.

        I'm not a versatile C programmer and AFAIK even C gurus get depressed when diving into perlguts.

        (BTW: the first link is defunc)

        > I imagine you might be able to peek at a regex structure using B,

        that would be nice...

        > but you can't get at the debug messages, they're not stored, and you can't hook DEBUG_COMPILE macros

        What exactly do you mean with "debug messages"? The token tree with commands like OPEN1?

        Or just message like

        anchored "1234" at 0 (checking anchored) minlen 4 Freeing REx: "(?<C>1)(?<D>2)(3)(?<A>4)"

        The latter I don't need! =)

        Cheers Rolf

        forgot the :)

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[davido]: so last -f /var/run/utmp on ubuntu provides similar (though more verbose) info
[oiskuu]: glibc getlogin just does ttyname() and falls back on getutline(); it's not security related at all. (reminds me of sendmail and remote finger services of the naive early spam era)
[Corion]: But yes, "who started this process" is interesting information :)
[tye]: no, I really believe that "login user" was added as a fundamental bit of info about each process in order to enhance the usefulness of auditing
[Corion]: Ah - if that information is saved in a file, then you could theoretically spam that file and confuse getlogin(). So, don't use it for authentication :)
[tye]: that is what getlogin() certainly *used* to do. I don't believe that is what it certainly should do.
[davido]: /var/run/utmp is 664 i think.
[tye]: Note that my "man getlogin" says that it uses stdin when it should use /dev/tty (calling a glibc bug). But that does not appear to be the case when I test it. But maybe Perl's getlogin() is not using glibc's getlogin().
[oiskuu]: well, run a strace and see what the getlogin does for you.... As I said. SELinux probably has those security labels. But not regular linux.
[tye]: for example, read https://unix. questions/146138/ loginuid-should-be -allowed-to-change -or-not-mutable-or -not

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