Subject: [PATCH] util/selinux: try opening the status page
  
Try opening the selinux status page for faster access to selinux status
values. If running on older kernels without the status page, simply
avoid using it.

Signed-off-by: David Rheinsberg <david@readahead.eu>
---
 src/util/selinux.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/util/selinux.c b/src/util/selinux.c
index 0264ea7..ea6af75 100644
--- a/src/util/selinux.c
+++ b/src/util/selinux.c
@@ -27,6 +27,7 @@ struct BusSELinuxName {
 typedef struct BusSELinuxName BusSELinuxName;
 
 static bool bus_selinux_avc_open;
+static bool bus_selinux_status_open;
 
 /** bus_selinux_is_enabled() - checks if SELinux is currently enabled
  *
@@ -360,6 +361,29 @@ int bus_selinux_init_global(void) {
                 bus_selinux_avc_open = true;
         }
 
+        if (!bus_selinux_status_open) {
+                r = selinux_status_open(0);
+                if (r == 0) {
+                        /*
+                         * The status page was successfully opened and can now
+                         * be used for faster selinux status-checks.
+                         */
+                        bus_selinux_status_open = true;
+                } else if (r > 0) {
+                        /*
+                         * >0 indicates success but with the netlink-fallback.
+                         * We didn't request the netlink-fallback, so close the
+                         * status-page again and treat it as unavailable.
+                         */
+                        selinux_status_close();
+                } else {
+                        /*
+                         * If the status page could not be opened, treat it as
+                         * unavailable and use the slower fallback functions.
+                         */
+                }
+        }
+
         selinux_set_callback(SELINUX_CB_LOG, (union selinux_callback)bus_selinux_log);
 
         /* XXX: set audit callback to get more metadata in the audit log? */
@@ -378,6 +402,11 @@ void bus_selinux_deinit_global(void) {
         if (!is_selinux_enabled())
                 return;
 
+        if (bus_selinux_status_open) {
+                selinux_status_close();
+                bus_selinux_status_open = false;
+        }
+
         if (bus_selinux_avc_open) {
                 avc_destroy();
                 bus_selinux_avc_open = false;
-- 
2.33.0