path: root/template/gnurl.html.j2

{% extends "common/base.j2" %}
{% block body_content %}
  <article class="container">
    <header>
      <h1>gnurl (libgnurl)</h1>
      <a href="#motivation">motivation</a>
      <a href="#rename">rename</a>
      <a href="#using">using</a>
      <a href="#gotchas">gotchas</a>
      <a href="#source">source</a>
      <a href="#downloads">downloads</a>
      <a href="#building">building</a>
      <a href="#reporting">reporting</a>
      <a href="#maintainer">maintainer</a>
    </header>

    <section class="container">
      <div class="row">
        <div class="col-md">
          <p>
            {% trans %}
              libgnurl is a micro fork of libcurl. The goal of
              libgnurl is to support only HTTP and HTTPS (and only
              HTTP 1.x) with a single crypto backend (GnuTLS) to
              ensure a small footprint and uniform experience for
              developers regardless of how libcurl was compiled.
            {% endtrans %}
          </p>
          <p>
            {% trans %}
              Our main usecase is for GNUnet and Taler, but it might
              be usable for others, hence we&#39;re releasing the code
              to the general public.
            {% endtrans %}
          </p>
          <p>
            {% trans %}
              libgnurl is released under the same license as
              libcurl. Please read the README for instructions, as you
              must supply the correct options to configure to get a
              proper build of libgnurl.
            {% endtrans %}
          </p>
        </div>
      </div>
      <div class="row">
        <div class="col-md">
          <h2>{{ _("About gnurl") }}</h3>
          <p>
            {% trans %}
              Large parts of the following 6 paragraphs are old and need
              to be rewritten.
            {% endtrans %}
          </p>
        </div>
      </div>
      <div class="row">
        <div class="col-md">
          <a name="motivation"></a>
          <h3>{{_("Motivation") }}</h4>
          <p>
            {% trans %}
              cURL supports many crypto backends. GNUnet requires the use of
              GnuTLS, but other variants are used by some distributions. Supporting
              other crypto backends would again expose us to a wider array of
              security issues, may create licensing issues and most importantly
              introduce new bugs as some crypto backends are known to introduce
              subtle runtime issues. While it is possible to have two versions of
              libcurl installed on the same system, this is error-prone, especially
              as if we are linked against the wrong version, the bugs that arise
              might be rather subtle.
            {% endtrans %}
          </p>
          <p>
            {% trans %}
	      For GNUnet, we also need a particularly modern version of
	      GnuTLS. Thus, it would anyway be necessary to recompile cURL for
	      GNUnet. But what happens if one links cURL against this version of
	      GnuTLS? Well, first one would install GnuTLS by hand in the
	      system. Then, we build cURL. cURL will build against it just fine, but
	      the linker will eventually complain bitterly. The reason is that cURL
	      also links against a bunch of other system libraries (gssapi, ldap,
	      ssh2, rtmp, krb5, sasl2, see discussion on obscure protocols above),
	      which --- as they are part of the distribution --- were linked against
	      an older version of GnuTLS. As a result, the same binary would be
	      linked against two different versions of GnuTLS. That is typically a
	      recipe for disaster. Thus, in order to avoid updating a dozen system
	      libraries (and having two versions of those installed), it is
	      necessary to disable all of those cURL features that GNUnet does not
	      use, and there are many of those. For GNUnet, the more obscure
	      protocols supported by cURL are close to dead code --- mostly
	      harmless, but not useful. However, as some application may use one of
	      those features, distributions are typically forced to enable all of
	      those features, and thus including security issues that might arise
	      from that code.
            {% endtrans %}
          </p>
          <p>
            {% trans %}
	      So to use a modern version of GnuTLS, a sane approach is to disable
	      all of the "optional" features of cURL that drag in system libraries
	      that link against the older GnuTLS. That works, except that one should
	      then NEVER install that version of libcurl in say /usr or /usr/local,
	      as that may break other parts of the system that might depend on these
	      features that we just disabled. Libtool versioning doesn't help here,
	      as it is not intended to deal with libraries that have optional
	      features. Naturally, installing cURL somewhere else is also
	      problematic, as we now need to be really careful that the linker will
	      link GNUnet against the right version. Note that none of this can
	      really be trivially fixed by the cURL developers.
            {% endtrans %}
          </p>
        </div>
      </div>
      <div class="row">
        <div class="col-md">
          <a name="rename"></a>
          <h3>{{_("Rename to fix") }}</h4>
          <p>
            {% trans %}
              How does forking fix it? Easy. First, we can get rid of all of the
              compatibility issues --- if you use libgnurl, you state that you don&#39;t
              need anything but HTTP/HTTPS. Those applications that need more,
              should stick with the original cURL. Those that do not, can choose to
              move to something simpler. As the library gets a new name, we do not
              have to worry about tons of packages breaking as soon as one rebuilds
              it. So renaming itself and saying that "libgnurl = libcurl with only
              HTTP/HTTPS support and GnuTLS" fixes 99%% of the problems that darkened
              my mood. Note that this pretty much CANNOT be done without a fork, as
              renaming is an essential part of the fix. Now, there might be creative
              solutions to achieve the same thing within the standard cURL build
              system, but this was deemed to be too much work when
              gnurl was originally started.
              The changes libgnurl makes to curl are miniscule and can
              easily be applied again and again whenever libcurl makes a new
              release.
            {% endtrans %}
          </p>
        </div>
        <div class="col-md">
          <a name="using"></a>
          <h3>{{_("Using libgnurl") }}</h4>
          <p>
            {% trans %}
              Projects that use cURL only for HTTP/HTTPS and that would work
              with GnuTLS should be able to switch to libgnurl by changing
              "-lcurl" to "-lgnurl". That&#39;s it. No changes to the source code
              should be required,
              as libgnurl strives for bug-for-bug compatibility with the
              HTTP/HTTPS/GnuTLS subset of cURL.
              We might add new features relating to this core subset if they
              are proposed, but so far we have kept our changes minimal and
              no additions to the original curl source have been written.
            {% endtrans %}
          </p>
        </div>
      </div>
      <div class="row">
        <div class="col-md">
          <a name="gotchas"></a>
          <h3>{{_("Gotchas") }}</h4>
          <p>
            {% trans %}
              libgnurl and gnurl are not intended to be used as a replacement
              for curl for users:
              <br>
              This does not mean there is no confidence in the work done
              with gnurl, it means that tools which expect curl or libcurl
              will not make use of a different named binary and library.
              If you know what you are doing, you should be able to use
              gnurl as part of your tooling in place of curl. We do not
              recommend to do so however, as the only usage it is tested
              for <em>so far</em> is as part of Taler&#39;s and GNunet&#39;s
              build-system.
              <br>
              Since no conflicts in filenames occur you are not expected
              to remove curl to make use of gnurl and viceversa.
            {% endtrans %}
          </p>
        </div>
      </div>

      <div class="row">
        <div class="col-md">
          <a name="source"></a>
          <h2>{{ _("Source Code") }}</h3>
          <p>
            {% trans %}
	      You can get the gnurl git repository using:
            {% endtrans %}
          </p>
          <ul>
	    <li>
              <code>git clone https://git.taler.net/gnurl.git</code>
            </li>
            <li>
	      <code>git clone git://git.taler.net/gnurl.git</code>
            </li>
          </ul>
          <p>
            {% trans %}
	      The versions are checked in as (signed) git tags.
            {% endtrans %}
          </p>
        </div>

        <div class="col-md">
          <a name="downloads"></a>
          <h2>{{ _("Downloads") }}</h3>
          <p>
            {% trans %}
	      Releases are published on <a href="https://ftpmirror.gnu.org/gnu/gnunet/">ftpmirror.gnu.org/gnu/gnunet</a>.
	      gnurl is available from within a variety of distributions and package managers.
	      Some Package Managers which include gnurl are:
              <a href="https://www.gnu.org/software/guix/">GNU Guix</a> (available as "gnurl"),
	      <a href="https://gentoo.org">Gentoo</a> through the collaborative ebuild collection
	      <a href="https://git.gnunet.org/youbroketheinternet-overlay.git/">youbroketheinternet</a>,
              <a href="https://nixos.org/nix/">Nix</a>, and as www/gnurl in
              <a href="https://pkgsrc.org">pkgsrc</a>.
            {% endtrans %}
          </p>
        </div>
      </div>

      <div class="row">
        <div class="col-md">
          <a name="building"></a>
          <h2>{{ _("Building gnurl") }}</h3>
          <p>
            {% trans %}
              We suggest to closely follow release announcements, as they
              might indicate changes in how gnurl is to be build.
              <br>
              If your package manager provides a binary build or build
              instructions to build gnurl from source automated and
              integrated with your environment, we strongly suggest to use
              this binary build.
              <br>
              There are two ways to build gnurl. The first one builds from
              the most recent git tag, the second one uses the distributed
              tarball. Distributors generally are supposed to build from
              the tarball, but we describe both methods here. Both methods
              are written with a NetBSD 9 userland in mind, substitute tools
              as necessary.
              <br>
              You should <b>avoid</b> building gnurl from the tip of the
              default git branch, as only tags are considered to be stable
              and approved builds.
            {% endtrans %}
          </p>
          <h3>{{ _("Building from the distributed tarball (prefered method)") }}</h4>
          <p>
            {% trans %}
              If you want to verify the signature, install an OpenPGP compatible tool such
              as security/gnupgp2 (and set it up). Assuming you use pkgin:
            {% endtrans %}
          </p>
          <ul>
            <li>
              pkgin update
            </li>
            <li>
              pkgin install gnupg2
            </li>
          </ul>
          <p>
            {% trans %}
              Fetch the signature key from
            {% endtrans %}
            <a href="https://keys.openpgp.org/search?q=nikita%40NetBSD.org">keys.openpgp.org</a>
            {% trans %}
              or via commandline with gnupg2.
            {% endtrans %}
          </p>
          <p>
            {% trans %}
              Fetch the release, the signature, the checksum file as well as its signature:
            {% endtrans %}
          </p>
          <ul>
            <li>
              ftp https://ftpmirror.gnu.org/gnu/gnunet/gnurl-7.65.3.tar.Z
            </li>
            <li>
              ftp https://ftpmirror.gnu.org/gnu/gnunet/gnurl-7.65.3.tar.Z.sig
            </li>
            <li>
              ftp https://ftpmirror.gnu.org/gnu.org/gnunet/gnurl-7.65.3.sum.txt
            </li>
            <li>
              ftp https://ftpmirror.gnu.org/gnu.org/gnunet/gnurl-7.65.3.sum.txt.sig
            </li>
          </ul>
          <p>
            {% trans %}
              verify the signatures, and verify the checksums against the
              checksums in the .sum.txt file.
            {% endtrans %}
          </p>
          <p>
            {% trans %}
              unpack the tarball:
            {% endtrans %}
          </p>
          <ul>
            <li>
              tar -zxf gnurl-7.65.3.tar.Z
            </li>
          </ul>
          <p>
            {% trans %}
              Change into the directory
            {% endtrans %}
          </p>
          <ul>
            <li>
              cd gnurl-7.65.3
            </li>
          </ul>
          <p>
            {% trans %}
              Now you can either run
            {% endtrans %}
          </p>
          <ul>
            <li>
              ./configure
            </li>
          </ul>
          <p>
            {% trans %}
              directly (and read configure-gnurl before you do so) or invoke
            {% endtrans %}
          </p>
          <ul>
            <li>
              ./configure-gnurl
            </li>
          </ul>
          <p>
            {% trans %}
              and pass additional parameters such as a custom PREFIX location.
              Further reference can be the
            {% endtrans %}
            <a href="http://pkgsrc.se/www/gnurl">www/gnurl</a> Makefile.
            {% trans %}
              Now run
            {% endtrans %}
          </p>
          <ul>
            <li>
              make
            </li>
            <li>
              make check
              {% trans %}
                (this is optional)
              {% endtrans %}
            </li>
            <li>
              make install
            </li>
          </ul>
          <p>
            {% trans %}
              and you are done.
            {% endtrans %}
          </p>
          <h3>{{ _("Building from a tagged git commit") }}</h4>
          <p>
            {% trans %}
              Follow the steps above, but instead of downloading the tarball,
              clone the git tag you want to build from.
            {% endtrans %}
          </p>
        </div>
      </div>

      <div class="row">
        <div class="col-md">
          <a name="reporting"></a>
          <h2>{{ _("Reporting Bugs") }}</h3>
          <p>
            {% trans %}
	      You can report bugs on our bug tracker:
	      <a href="https://bugs.gnunet.org/">bugs.gnunet.org</a>. Alternatively
	      you can use our bug mailinglist, but we prefer to track bugs
	      on the bugtracker.
            {% endtrans %}
          </p>
        </div>

        <div class="col-md">
          <a name="maintainer"></a>
          <h2>{{ _("Maintainer and Cryptographic signatures") }}</h3>
          <p>
            {% trans %}
	      gnurl/libgnurl is maintained by Nikita.
	      Releases after version 7.69.1 are signed with the OpenPGP Key
              <b>0xD6B570842F7E7F8D</b> (<a href="https://keys.openpgp.org/search?q=6115012DEA3026F62A98A556D6B570842F7E7F8D">keys.openpgp.org</a>, <a href="https://n0.is/pubkey.asc">n0.is</a>), with the key fingerprint
              <b>6115 012D EA30 26F6 2A98  A556 D6B5 7084 2F7E 7F8D</b>.
            {% endtrans %}
          </p>
        </div>
      </div>
    </section>
  </article> <!-- /container -->
{% endblock body_content %}