[libvirt] [PATCH] LXC: workaround machined uncleaned data with containers running systemd.

[Cédric Bosdonnat]

The problem is described by [0] but its effect on libvirt is that
starting a container with a full distro running systemd after having
stopped it simply fails.

The container cleanup now calls the machined Terminate function to make
sure that everything is in order for the next run.

 [0]: https://bugs.freedesktop.org/show_bug.cgi?id=68370
---
 src/Makefile.am       |  4 +++-
 src/lxc/lxc_process.c |  8 ++++++++
 src/util/virsystemd.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/util/virsystemd.h |  4 ++++
 4 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/src/Makefile.am b/src/Makefile.am
index 4375ef7..211b42e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1170,7 +1170,9 @@ EXTRA_DIST += qemu/qemu.conf qemu/libvirtd_qemu.aug \
 if WITH_LXC
 noinst_LTLIBRARIES += libvirt_driver_lxc_impl.la
 libvirt_driver_lxc_la_SOURCES =
-libvirt_driver_lxc_la_LIBADD = libvirt_driver_lxc_impl.la
+libvirt_driver_lxc_la_LIBADD = \
+		libvirt_driver_lxc_impl.la \
+		libvirt_util.la
 if WITH_DRIVER_MODULES
 mod_LTLIBRARIES += libvirt_driver_lxc.la
 libvirt_driver_lxc_la_LIBADD += ../gnulib/lib/libgnu.la
diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c
index 4835bd5..f92c613 100644
--- a/src/lxc/lxc_process.c
+++ b/src/lxc/lxc_process.c
@@ -50,6 +50,7 @@
 #include "virstring.h"
 #include "viratomic.h"
 #include "virprocess.h"
+#include "virsystemd.h"
 
 #define VIR_FROM_THIS VIR_FROM_LXC
 
@@ -210,6 +211,13 @@ static void virLXCProcessCleanup(virLXCDriverPtr driver,
         virCgroupFree(&priv->cgroup);
     }
 
+    /* Get machined to terminate the machine as it may not have cleaned it
+     * properly. See https://bugs.freedesktop.org/show_bug.cgi?id=68370 for
+     * the bug we are working around here.
+     */
+    virSystemdTerminateMachine(vm->def->name, "lxc", true);
+
+
     /* now that we know it's stopped call the hook if present */
     if (virHookPresent(VIR_HOOK_DRIVER_LXC)) {
         char *xml = virDomainDefFormat(vm->def, 0);
diff --git a/src/util/virsystemd.c b/src/util/virsystemd.c
index e72b7f0..3320e53 100644
--- a/src/util/virsystemd.c
+++ b/src/util/virsystemd.c
@@ -242,3 +242,58 @@ cleanup:
     VIR_FREE(slicename);
     return ret;
 }
+
+int virSystemdTerminateMachine(const char *name,
+                               const char *drivername,
+                               bool privileged)
+{
+    int ret;
+    DBusConnection *conn;
+    char *machinename = NULL;
+    char *username = NULL;
+
+    ret = virDBusIsServiceEnabled("org.freedesktop.machine1");
+    if (ret < 0)
+        return ret;
+
+    conn = virDBusGetSystemBus();
+
+    ret = -1;
+    if (privileged) {
+        if (virAsprintf(&machinename, "%s-%s", drivername, name) < 0)
+            goto cleanup;
+    } else {
+        if (!(username = virGetUserName(geteuid())))
+            goto cleanup;
+        if (virAsprintf(&machinename, "%s-%s-%s", username, drivername, name) < 0)
+            goto cleanup;
+    }
+
+    /*
+     * The systemd DBus API we're invoking has the
+     * following signature
+     *
+     * TerminateMachine(in  s name);
+     *
+     * @name a host unique name for the machine. shows up
+     * in 'ps' listing & similar
+     */
+
+    VIR_DEBUG("Attempting to terminate machine via systemd");
+    if (virDBusCallMethod(conn,
+                          NULL,
+                          "org.freedesktop.machine1",
+                          "/org/freedesktop/machine1",
+                          "org.freedesktop.machine1.Manager",
+                          "TerminateMachine",
+                          "s",
+                          machinename) < 0)
+        goto cleanup;
+
+    ret = 0;
+
+cleanup:
+    VIR_FREE(username);
+    VIR_FREE(machinename);
+    return ret;
+}
diff --git a/src/util/virsystemd.h b/src/util/virsystemd.h
index 414ae5a..6c9c6df 100644
--- a/src/util/virsystemd.h
+++ b/src/util/virsystemd.h
@@ -38,4 +38,8 @@ int virSystemdCreateMachine(const char *name,
                             bool iscontainer,
                             const char *partition);
 
+int virSystemdTerminateMachine(const char *name,
+                               const char *drivername,
+                               bool privileged);
+
 #endif /* __VIR_SYSTEMD_H__ */
-- 
1.8.4