sd-journal: introduce has_runtime_files and has_persistent_files

Also introduce sd_journal_has_runtime_files() and
sd_journal_has_persistent_files() to the public API. These functions
can be used to easily find out if the open journal files are runtime
and/or persistent.

2 files changed, 101 insertions, 2 deletions

diff --git a/man/sd-journal.xml b/man/sd-journal.xml
index 9b1a52207f..a1185d372b 100644
--- a/man/sd-journal.xml
+++ b/man/sd-journal.xml
@@ -81,9 +81,11 @@
     <citerefentry><refentrytitle>sd_journal_get_cutoff_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
     <citerefentry><refentrytitle>sd_journal_get_cutoff_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
     <citerefentry><refentrytitle>sd_journal_get_usage</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
-    <citerefentry><refentrytitle>sd_journal_get_catalog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    <citerefentry><refentrytitle>sd_journal_get_catalog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+    <citerefentry><refentrytitle>sd_journal_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+    <citerefentry><refentrytitle>sd_journal_has_runtime_files</refentrytitle><manvolnum>3</manvolnum></citerefentry>
     and
-    <citerefentry><refentrytitle>sd_journal_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    <citerefentry><refentrytitle>sd_journal_has_persistent_files</refentrytitle><manvolnum>3</manvolnum></citerefentry>
     for more information about the functions implemented.</para>
 
     <para>Command line access for submitting entries to the journal is
@@ -116,6 +118,8 @@
       <citerefentry><refentrytitle>sd_journal_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>sd_journal_query_unique</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>sd_journal_get_catalog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_journal_has_runtime_files</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_journal_has_persistent_files</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
       <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
diff --git a/man/sd_journal_has_runtime_files.xml b/man/sd_journal_has_runtime_files.xml
new file mode 100644
index 0000000000..237e649206
--- /dev/null
+++ b/man/sd_journal_has_runtime_files.xml
@@ -0,0 +1,95 @@
+<?xml version='1.0'?> <!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<!--
+  This file is part of systemd.
+
+  Copyright 2016 Jan Synáček
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  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="sd_journal_has_runtime_files">
+
+  <refentryinfo>
+    <title>sd_journal_has_runtime_files</title>
+    <productname>systemd</productname>
+
+    <authorgroup>
+      <author>
+        <contrib>Developer</contrib>
+        <firstname>Jan</firstname>
+        <surname>Synáček</surname>
+        <email>jan.synacek@gmail.com</email>
+      </author>
+    </authorgroup>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>sd_journal_has_runtime_files</refentrytitle>
+    <manvolnum>3</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>sd_journal_has_runtime_files</refname>
+    <refname>sd_journal_has_persistent_files</refname>
+    <refpurpose>Query availability of runtime or persistent journal files.</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;systemd/sd-journal.h&gt;</funcsynopsisinfo>
+
+      <funcprototype>
+        <funcdef>int <function>sd_journal_has_runtime_files</function></funcdef>
+        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_journal_has_persistent_files</function></funcdef>
+        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
+      </funcprototype>
+
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><function>sd_journal_has_runtime_files()</function> returns a positive value
+    if runtime journal files (present in /run/systemd/journal/) have been found.
+    Otherwise returns 0.</para>
+
+    <para><function>sd_journal_has_persistent_files()</function> returns a positive value
+    if persistent journal files (present in /var/log/journal/) have been found.
+    Otherwise returns 0.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Return value</title>
+    <para>Both <function>sd_journal_has_runtime_files()</function>
+    and <function>sd_journal_has_persistent_files()</function> return -EINVAL
+    if their argument is NULL.
+    </para>
+  </refsect1>
+
+  <refsect1>
+    <title>See Also</title>
+    <para>
+      <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>