[gnome-software/wip/hughsie/plugin-fedora-liveusb] Add a plugin to disable updates when running on a Fedora LiveUSB image

[Richard Hughes <rhughes src gnome org>]

commit cb946dcae33eb66a38f80c9040af1f62a217c207
Author: Richard Hughes <richard hughsie com>
Date:   Mon Oct 31 09:08:58 2016 +0000

    Add a plugin to disable updates when running on a Fedora LiveUSB image

 contrib/gnome-software.spec.in         |    1 +
 src/plugins/Makefile.am                |    6 ++++
 src/plugins/gs-plugin-fedora-liveusb.c |   45 ++++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 0 deletions(-)
---
diff --git a/contrib/gnome-software.spec.in b/contrib/gnome-software.spec.in
index f60586b..ae08821 100644
--- a/contrib/gnome-software.spec.in
+++ b/contrib/gnome-software.spec.in
@@ -158,6 +158,7 @@ glib-compile-schemas %{_datadir}/glib-2.0/schemas &> /dev/null || :
 %{_libdir}/gs-plugins-%{gs_plugin_version}/libgs_plugin_external-appstream.so
 %{_libdir}/gs-plugins-%{gs_plugin_version}/libgs_plugin_fedora-distro-upgrades.so
 %{_libdir}/gs-plugins-%{gs_plugin_version}/libgs_plugin_fedora-tagger-usage.so
+%{_libdir}/gs-plugins-%{gs_plugin_version}/libgs_plugin_fedora-liveusb.so
 %{_libdir}/gs-plugins-%{gs_plugin_version}/libgs_plugin_flatpak-system.so
 %{_libdir}/gs-plugins-%{gs_plugin_version}/libgs_plugin_flatpak-user.so
 %{_libdir}/gs-plugins-%{gs_plugin_version}/libgs_plugin_fwupd.so
diff --git a/src/plugins/Makefile.am b/src/plugins/Makefile.am
index de0782e..9c7241a 100644
--- a/src/plugins/Makefile.am
+++ b/src/plugins/Makefile.am
@@ -42,6 +42,7 @@ plugin_LTLIBRARIES =                                  \
        libgs_plugin_hardcoded-popular.la               \
        libgs_plugin_hardcoded-featured.la              \
        libgs_plugin_fedora-distro-upgrades.la          \
+       libgs_plugin_fedora-liveusb.la                  \
        libgs_plugin_provenance.la                      \
        libgs_plugin_provenance-license.la              \
        libgs_plugin_repos.la                           \
@@ -161,6 +162,11 @@ libgs_plugin_fedora_distro_upgrades_la_LIBADD = $(GS_PLUGIN_LIBS) $(JSON_GLIB_LI
 libgs_plugin_fedora_distro_upgrades_la_LDFLAGS = -module -avoid-version
 libgs_plugin_fedora_distro_upgrades_la_CFLAGS = $(GS_PLUGIN_CFLAGS) $(JSON_GLIB_CFLAGS) $(WARN_CFLAGS)
 
+libgs_plugin_fedora_liveusb_la_SOURCES = gs-plugin-fedora-liveusb.c
+libgs_plugin_fedora_liveusb_la_LIBADD = $(GS_PLUGIN_LIBS) $(JSON_GLIB_LIBS) $(SOUP_LIBS)
+libgs_plugin_fedora_liveusb_la_LDFLAGS = -module -avoid-version
+libgs_plugin_fedora_liveusb_la_CFLAGS = $(GS_PLUGIN_CFLAGS) $(JSON_GLIB_CFLAGS) $(WARN_CFLAGS)
+
 if HAVE_GUDEV
 libgs_plugin_modalias_la_SOURCES = gs-plugin-modalias.c
 libgs_plugin_modalias_la_LIBADD = $(GS_PLUGIN_LIBS) $(GUDEV_LIBS)
diff --git a/src/plugins/gs-plugin-fedora-liveusb.c b/src/plugins/gs-plugin-fedora-liveusb.c
new file mode 100644
index 0000000..f9d04bd
--- /dev/null
+++ b/src/plugins/gs-plugin-fedora-liveusb.c
@@ -0,0 +1,45 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2016 Richard Hughes <richard hughsie com>
+ *
+ * Licensed under the GNU General Public License Version 2
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <config.h>
+
+#include <gnome-software.h>
+
+void
+gs_plugin_initialize (GsPlugin *plugin)
+{
+       if (!gs_plugin_check_distro_id (plugin, "fedora"))
+               gs_plugin_set_enabled (plugin, FALSE);
+}
+
+gboolean
+gs_plugin_setup (GsPlugin *plugin, GCancellable *cancellable, GError **error)
+{
+       g_autofree gchar *data = NULL;
+       if (!g_file_get_contents ("/proc/cmdline", &data, NULL, error)) {
+               g_prefix_error (error, "failed to get kernel command line: ");
+               return FALSE;
+       }
+       g_debug ("kernel command line: %s", data);
+       if (g_strstr_len (data, -1, "root=live") != NULL)
+               gs_plugin_set_allow_updates (plugin, FALSE);
+       return TRUE;
+}