Licensing check in a loadable .so

Discussion in 'C++' started by Sandeep Srinivasa, Apr 7, 2005.

  1. hi,
    I have a software which has licensing (enabled through flexlm).
    Now, an end user can build apps (As loadable modules) using this base
    software.
    I am introducing a new feature, which I am providing as a .so . The
    development teams, release schedules, etc. are completely different
    for the base software and the new .so .

    1. Is it possible for me to enable licensing for the loadable .so ?

    The problem is that as soon as the .so is loaded, all functions become
    visible to the end-user who has a license for the base-app, but not
    the .so .

    I could of course use the dlopen method, but my .so has a thousand
    different functions, all of which need to dlsym-ed . Rather than doing
    this, I would like a check right when the .so is loaded and forget
    about it later.

    2. Is there a way to check for licensing in the .init section of
    the .so ?

    3. Will this be portable across platforms (Linux, Sun, HP 11.11) .

    regards and thanks in advance
    -Sandeep
     
    Sandeep Srinivasa, Apr 7, 2005
    #1
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  2. [answering in comp.lang.c++, keeping the OP's cross-post]
    Sandeep Srinivasa wrote:
    > hi,
    > I have a software which has licensing (enabled through flexlm).
    > Now, [...]


    Please don't cross-post this to comp.lang.c++, it's off-topic here.
    Thanks!
     
    Victor Bazarov, Apr 7, 2005
    #2
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  3. Sandeep Srinivasa

    Alvin Beach Guest

    Re: Licensing check in a loadable .so [OT?]

    Sandeep Srinivasa wrote:

    > hi,
    > I have a software which has licensing (enabled through flexlm).
    > Now, an end user can build apps (As loadable modules) using this base
    > software.
    >

    (snip)
    > 2. Is there a way to check for licensing in the .init section of
    > the .so ?


    This may be slightly off topic, but:

    How do you access the .init section of a .so that isn't loaded by dlopen?
    I'm curious because I have tend to make .so libraries for my apps[1] and
    let the OS load the .so when the app starts.

    I've always thought of .so files like .a (static libraries) except, the OS
    just links the .so at runtime (instead of compile time).


    [1] I make the libraries using -shared -fPIC switches for gcc.

    --
    Alvin
     
    Alvin Beach, Apr 7, 2005
    #3
  4. Sandeep Srinivasa

    Guest

    , Apr 8, 2005
    #4
  5. Re: Licensing check in a loadable .so [OT?]

    I'm not entirely sure, but I guess it could be possible through the
    "constructor" attribute of gcc.
    -regards
    SSS

    Alvin Beach <reply@in_newsgroup.ca> wrote in message news:<Bac5e.6862$vt1.6616@edtnps90>...
    > Sandeep Srinivasa wrote:
    >
    > > hi,
    > > I have a software which has licensing (enabled through flexlm).
    > > Now, an end user can build apps (As loadable modules) using this base
    > > software.
    > >

    > (snip)
    > > 2. Is there a way to check for licensing in the .init section of
    > > the .so ?

    >
    > This may be slightly off topic, but:
    >
    > How do you access the .init section of a .so that isn't loaded by dlopen?
    > I'm curious because I have tend to make .so libraries for my apps[1] and
    > let the OS load the .so when the app starts.
    >
    > I've always thought of .so files like .a (static libraries) except, the OS
    > just links the .so at runtime (instead of compile time).
    >
    >
    > [1] I make the libraries using -shared -fPIC switches for gcc.
     
    Sandeep Srinivasa, Apr 8, 2005
    #5
  6. Sandeep Srinivasa

    Guest

    Jan Kandziora wrote:
    > Sandeep Srinivasa schrieb:
    >
    > > hi,
    > > I have a software which has licensing (enabled through flexlm).
    > > Now, an end user can build apps (As loadable modules) using this

    base
    > > software.
    > >

    > I can't think of any software mechanism for licensing/copy protection

    that
    > can't easily be bypassed by any advanced programmer.
    >
    > You are just annoying paying customers, who will switch to a

    "cracked"
    > version very soon, as the don't like the whole hassle with your

    licensing
    > scheme. The will pay for your software, but think you are dumb - like

    they
    > hate Microsoft for their "product activation".
    >
    > Don't put too much effort into this "licensing enforcement", as it

    isn't
    > worth the work. There is a whole herd of people out there who will

    break
    > into your software just because it annoys them. You can't win.
    > --
    > Jan



    The license check can be as difficult to disable as you like; some
    folks
    enjoy this game. Just make sure that the product does nothing worse
    than
    nag the user if he doesn't appear to have the correct license. That
    way, when
    their license server craps out, or they have to replace their machine
    on Friday
    evening before a monday deadline, your licensing check isn't the reason
    they
    didn't make their deadlines.

    Nothing worse than having your distrust of your customer be the reason
    they don't make
    their quarter.

    - Bart
     
    , Apr 9, 2005
    #6
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