Bug#904248: Beginnings of a patch to add netbase to build-essential

[Ian Jackson <ijackson@chiark.greenend.org.uk>]

Sean Whitton writes ("Beginnings of a patch to add netbase to build-essential"):
> Ian also thinks that package builds should be able to access the
> information normally contained in /etc/protocols and /etc/services by
> means of the C standard library.

Yes.

> Could you say more about why this is needed, and provide wording for a
> third bullet point in the list in my patch, which describes the
> functionality of /etc/protocols and /etc/services, please?

Sorry for the delay replying to this.

I think this is needed because some build systems look at
/etc/{services,protocols} at build-time to (for example) bake into the
program the default port number, or, in some cases, protocol numbers.
The values in these files are largely fixed or conventional, so this
is quite appropriate.  Expecting programs to add explicit dependencies
on netbase for this seems silly - there is little benefit, since the
files are small and the implementation of the lookup where done via
the libc) is part of the libc.  And of course any notionally-missing
dependencies on netbase would not be discovered.

I suggest this text:

  - for the package build to look up longstanding and conventionally
    available service and protocol names and numbers, either by
    directly reading /etc/services and /etc/protocols or by using the
    corresponding functions from the C standard library.  (If the
    package needs to look up a more recent service or protocol, and
    certainly if the service or protocol was not listed in these files
    in the package's targeted Debian releases, an appropriate
    versioned build-dependency is needed.)

Ian.

-- 
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