Re: setproctitle()

[Jim Meyering]

Peter Seebach wrote:

> In message <address@hidden>, Jim Meyering writes:
>>Thanks for volunteering.  Yes, this would be useful.
>>There are many implementations floating around.
>
> There are indeed a ton.
>
>>Can you assign copyright to the FSF?
>
> I think I can.  There is some ambiguity about the IP agreement at $dayjob,
> but we do in general contribute some stuff to the FSF, so I can probably
> route it through the open source contribution mechanism.
>
> My thought is that the first step towards a setproctitle() implementation
> is a pure stub.  The function returns void anyway, and I'm not aware of any
> usage where anyone but a human user scanning the 'ps' list cares whether it
> worked.  Then, specific implementations can be tweaked.
>
> For BSD libc, of course, no implementation is needed.
>
> For glibc, there is a beautiful bit of trickery available.  The

On Linux-based systems, it looks like prctl (PR_SET_NAME, ...
could be an option.

> program invocation name really *is* argv[0], apparently.  You can
> thus scan consecutive strings from there, until you find something
> that aligns with environ[0], and have a pretty good guess that
> you've found the length of the arguments...  If nothing's moved.
> I'm not sure how to cleanly check whether anything has moved.  (The
> key to this all is that you are allowed to generate a pointer one
> past the end of an array, and even though you can't dereference
> it, you can compare it to other pointers for equality/inequality,
> though not for less-than/greater-than.  So if the address just past
> the end of argv[argc-1] is the same address as environ[0], you can
> iterate through a bit further checking for values that can be known
> to be part of a contiguous block...
>
> The alternative is to have something like setproctitle_init().  My
> guess is that the ideal case would be to use setproctitle_init()
> if possible, but if someone calls setproctitle() without doing so,
> make reasonable guesses.
>
> My original plan had been to release the ensuing code into the public domain
> so that people could use it arbitrarily; in particular, I wanted to use it
> with a hunk of code where I really don't want to create any license
> interdependency issues...  I'm sort of torn here, because on the one hand,
> I would love to see this in gnulib so people will stop needing to reinvent
> it so much, but that does imply losing the right to use the code in
> conjunction with, say, any of the proprietary stuff we sometimes ship.
> Which would be inconvenient.  (More concretely, the program for which I
> need this is LGPLv*2*.)

Can you simply declare the copyright to be LGPLv2+?
Many modules are already LGPLv2+ (see modules/*).