journal-remote: HTTP(s) support

The whole tool is made dependent on µhttpd availability. It should be
easy to make the µhttpd parts conditional, but since transfer over
HTTP seems to be the primary use case, currently this is not done.

Current implementation uses nested epoll loops: sd-event is used for
the external event loop, and µhttpd uses epoll in its own
loop. Unfortunately µhttpd does not expose enough information to add
the descriptors it uses to the external event loop. This means that
starvation of other events is possible, if one of the inner µhttpd
loops is constantly busy. This means that µhttpd servers should not
be mixed with other sources.

The TLS authentication parts haven't been really tested properly, and
should not be take too seriously.

1 files changed, 18 insertions, 3 deletions

diff --git a/man/systemd-journal-remote.xml b/man/systemd-journal-remote.xml
index 036d0bcb4..ef123ce48 100644
--- a/man/systemd-journal-remote.xml
+++ b/man/systemd-journal-remote.xml
@@ -21,7 +21,7 @@ You should have received a copy of the GNU Lesser General Public License
 along with systemd; If not, see <http://www.gnu.org/licenses/>.
 -->
 
-<refentry id="systemd-journal-remote">
+<refentry id="systemd-journal-remote" conditional='HAVE_MICROHTTPD'>
 
   <refentryinfo>
     <title>systemd-journal-remote</title>
@@ -130,8 +130,8 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
       <varlistentry>
         <term><option>--listen-raw=<replaceable>ADDRESS</replaceable></option></term>
 
-        <listitem><para><option>ADDRESS</option> must be an address
-        suitable for <option>ListenStream=</option> (c.f.
+        <listitem><para><replaceable>ADDRESS</replaceable> must be an
+        address suitable for <option>ListenStream=</option> (c.f.
         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
         <command>systemd-journal-remote</command> will listen on this
         socket for connections. Each connection is expected to be a
@@ -140,6 +140,21 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
       </varlistentry>
 
       <varlistentry>
+        <term><option>--listen-http=<replaceable>ADDRESS</replaceable></option></term>
+        <term><option>--listen-https=<replaceable>ADDRESS</replaceable></option></term>
+
+        <listitem><para><replaceable>ADDRESS</replaceable> must be an
+        address suitable for <option>ListenStream=</option> (c.f.
+        <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
+        HTTP or HTTPS server will be spawned on this port,
+        respectively, for the first and second options. Currenntly
+        Only POST requests to <filename>/upload</filename> with
+        <literal>Content-Type: application/vnd.fdo.journal</literal>
+        are supported.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><varname>$LISTEN_FDS</varname></term>
 
         <listitem><para><command>systemd-journal-remote</command>