LXC driver: started implementing connectDomainXMLFromNative

This function aims at converting LXC configuration into a libvirt
domain XML description to help users migrate from LXC to libvirt.

Here is an example of how the lxc configuration works:
virsh -c lxc:/// domxml-from-native lxc-tools /var/lib/lxc/migrate_test/config

It is possible that some parts couldn't be properly mapped into a
domain XML fragment, so users should carefully review the result
before creating the domain.

fstab files in lxc.mount lines will need to be merged into the
configuration file as lxc.mount.entry.

As we can't know the amount of memory of the host, we have to set a
default value for max_balloon that users will probably want to adjust.

.gitignore

@@ -157,6 +157,7 @@
 /tests/hashtest
 /tests/jsontest
 /tests/libvirtdconftest
+/tests/lxcconf2xmltest
 /tests/metadatatest
 /tests/networkxml2argvtest
 /tests/nodeinfotest

po/POTFILES.in

@@ -62,6 +62,7 @@ src/locking/sanlock_helper.c
 src/lxc/lxc_cgroup.c
 src/lxc/lxc_fuse.c
 src/lxc/lxc_hostdev.c
+src/lxc/lxc_native.c
 src/lxc/lxc_container.c
 src/lxc/lxc_conf.c
 src/lxc/lxc_controller.c

src/Makefile.am

@@ -619,6 +619,7 @@ LXC_DRIVER_SOURCES =						\
 		lxc/lxc_monitor.c lxc/lxc_monitor.h		\
 		lxc/lxc_process.c lxc/lxc_process.h		\
 		lxc/lxc_fuse.c lxc/lxc_fuse.h			\
+		lxc/lxc_native.c lxc/lxc_native.h		\
 		lxc/lxc_driver.c lxc/lxc_driver.h
 
 LXC_CONTROLLER_SOURCES =					\

src/lxc/lxc_driver.c

@@ -44,6 +44,7 @@
 #include "lxc_container.h"
 #include "lxc_domain.h"
 #include "lxc_driver.h"
+#include "lxc_native.h"
 #include "lxc_process.h"
 #include "viralloc.h"
 #include "virnetdevbridge.h"
@@ -988,6 +989,35 @@ cleanup:
     return ret;
 }
 
+static char *lxcConnectDomainXMLFromNative(virConnectPtr conn,
+                                           const char *nativeFormat,
+                                           const char *nativeConfig,
+                                           unsigned int flags)
+{
+    char *xml = NULL;
+    virDomainDefPtr def = NULL;
+
+    virCheckFlags(0, NULL);
+
+    if (virConnectDomainXMLFromNativeEnsureACL(conn) < 0)
+        goto cleanup;
+
+    if (STRNEQ(nativeFormat, LXC_CONFIG_FORMAT)) {
+        virReportError(VIR_ERR_INVALID_ARG,
+                       _("unsupported config type %s"), nativeFormat);
+        goto cleanup;
+    }
+
+    if (!(def = lxcParseConfigString(nativeConfig)))
+        goto cleanup;
+
+    xml = virDomainDefFormat(def, 0);
+
+cleanup:
+    virDomainDefFree(def);
+    return xml;
+}
+
 /**
  * lxcDomainCreateWithFiles:
  * @dom: domain to start
@@ -5374,6 +5404,7 @@ static virDriver lxcDriver = {
     .domainGetSecurityLabel = lxcDomainGetSecurityLabel, /* 0.9.10 */
     .nodeGetSecurityModel = lxcNodeGetSecurityModel, /* 0.9.10 */
     .domainGetXMLDesc = lxcDomainGetXMLDesc, /* 0.4.2 */
+    .connectDomainXMLFromNative = lxcConnectDomainXMLFromNative, /* 1.2.2 */
     .connectListDefinedDomains = lxcConnectListDefinedDomains, /* 0.4.2 */
     .connectNumOfDefinedDomains = lxcConnectNumOfDefinedDomains, /* 0.4.2 */
     .domainCreate = lxcDomainCreate, /* 0.4.4 */

src/lxc/lxc_native.c

+/*
+ * lxc_native.c: LXC native configuration import
+ *
+ * Copyright (c) 2013 SUSE LINUX Products GmbH, Nuernberg, Germany.
+ *
+ * This library 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.
+ *
+ * This library 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 this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Cedric Bosdonnat <cbosdonnat@suse.com>
+ */
+
+#include <config.h>
+
+#include "internal.h"
+#include "lxc_native.h"
+#include "util/viralloc.h"
+#include "util/virlog.h"
+#include "util/virstring.h"
+#include "util/virconf.h"
+
+#define VIR_FROM_THIS VIR_FROM_LXC
+
+virDomainDefPtr
+lxcParseConfigString(const char *config)
+{
+    virDomainDefPtr vmdef = NULL;
+    virConfPtr properties = NULL;
+    virConfValuePtr value;
+
+    if (!(properties = virConfReadMem(config, 0, VIR_CONF_FLAG_LXC_FORMAT)))
+        return NULL;
+
+    if (VIR_ALLOC(vmdef) < 0)
+        goto error;
+
+    if (virUUIDGenerate(vmdef->uuid) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("failed to generate uuid"));
+        goto error;
+    }
+    vmdef->id = -1;
+    vmdef->mem.max_balloon = 64 * 1024;
+
+    vmdef->onReboot = VIR_DOMAIN_LIFECYCLE_RESTART;
+    vmdef->onCrash = VIR_DOMAIN_LIFECYCLE_DESTROY;
+    vmdef->onPoweroff = VIR_DOMAIN_LIFECYCLE_DESTROY;
+    vmdef->virtType = VIR_DOMAIN_VIRT_LXC;
+
+    /* Value not handled by the LXC driver, setting to
+     * minimum required to make XML parsing pass */
+    vmdef->maxvcpus = 1;
+
+    if (VIR_STRDUP(vmdef->os.type, "exe") < 0)
+        goto error;
+
+    if (VIR_STRDUP(vmdef->os.init, "/sbin/init") < 0)
+        goto error;
+
+    if (!(value = virConfGetValue(properties, "lxc.utsname")) ||
+            !value->str || (VIR_STRDUP(vmdef->name, value->str) < 0))
+        goto error;
+    if (!vmdef->name && (VIR_STRDUP(vmdef->name, "unnamed") < 0))
+        goto error;
+
+    goto cleanup;
+
+error:
+    virDomainDefFree(vmdef);
+    vmdef = NULL;
+
+cleanup:
+    virConfFree(properties);
+
+    return vmdef;
+}

src/lxc/lxc_native.h

+/*
+ * lxc_native.h: LXC native configuration import
+ *
+ * Copyright (c) 2013 SUSE LINUX Products GmbH, Nuernberg, Germany.
+ *
+ * This library 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.
+ *
+ * This library 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 this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Cedric Bosdonnat <cbosdonnat@suse.com>
+ */
+
+#ifndef __LXC_NATIVE_H__
+# define __LXC_NATIVE_H__
+
+# include "domain_conf.h"
+
+# define LXC_CONFIG_FORMAT "lxc-tools"
+
+virDomainDefPtr lxcParseConfigString(const char *config);
+
+#endif /* __LXC_NATIVE_H__ */

tests/Makefile.am

@@ -200,7 +200,7 @@ test_programs += qemuxml2argvtest qemuxml2xmltest qemuxmlnstest \
 endif WITH_QEMU
 
 if WITH_LXC
-test_programs += lxcxml2xmltest
+test_programs += lxcxml2xmltest lxcconf2xmltest
 endif WITH_LXC
 
 if WITH_OPENVZ
@@ -523,6 +523,11 @@ lxcxml2xmltest_SOURCES = \
 	lxcxml2xmltest.c testutilslxc.c testutilslxc.h \
 	testutils.c testutils.h
 lxcxml2xmltest_LDADD = $(lxc_LDADDS)
+
+lxcconf2xmltest_SOURCES = \
+	lxcconf2xmltest.c \
+	testutils.c testutils.h
+lxcconf2xmltest_LDADD = $(lxc_LDADDS)
 else ! WITH_LXC
 EXTRA_DIST += lxcxml2xmltest.c testutilslxc.c testutilslxc.h
 endif ! WITH_LXC

tests/lxcconf2xmldata/lxcconf2xml-simple.config

+# Template used to create this container: opensuse
+# Template script checksum (SHA-1): 27307e0a95bd81b2c0bd82d6f87fdbe83be075ef
+
+lxc.network.type = veth
+lxc.network.flags = up
+lxc.network.link = virbr0
+lxc.network.hwaddr = 02:00:15:8f:05:c1
+lxc.network.name = eth0
+
+#remove next line if host DNS configuration should not be available to container
+lxc.mount.entry = /etc/resolv.conf etc/resolv.conf none bind,ro 0 0
+lxc.rootfs = /var/lib/lxc/migrate_test/rootfs
+lxc.utsname = migrate_test
+lxc.autodev=1
+lxc.tty = 2
+lxc.pts = 1024
+lxc.mount = /var/lib/lxc/migrate_test/fstab
+lxc.cap.drop = sys_module mac_admin mac_override mknod
+
+# When using LXC with apparmor, uncomment the next line to run unconfined:
+#lxc.aa_profile = unconfined
+
+lxc.cgroup.devices.deny = a
+# /dev/null and zero
+lxc.cgroup.devices.allow = c 1:3 rwm
+lxc.cgroup.devices.allow = c 1:5 rwm
+# consoles
+lxc.cgroup.devices.allow = c 5:1 rwm
+lxc.cgroup.devices.allow = c 5:0 rwm
+lxc.cgroup.devices.allow = c 4:0 rwm
+lxc.cgroup.devices.allow = c 4:1 rwm
+# /dev/{,u}random
+lxc.cgroup.devices.allow = c 1:9 rwm
+lxc.cgroup.devices.allow = c 1:8 rwm
+lxc.cgroup.devices.allow = c 136:* rwm
+lxc.cgroup.devices.allow = c 5:2 rwm
+# rtc
+lxc.cgroup.devices.allow = c 254:0 rwm

tests/lxcconf2xmldata/lxcconf2xml-simple.xml

+<domain type='lxc'>
+  <name>migrate_test</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>65536</memory>
+  <currentMemory unit='KiB'>0</currentMemory>
+  <vcpu placement='static' current='0'>1</vcpu>
+  <os>
+    <type>exe</type>
+    <init>/sbin/init</init>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+  </devices>
+</domain>

tests/lxcconf2xmltest.c

+#include <config.h>
+
+#include "testutils.h"
+
+#ifdef WITH_LXC
+
+# include "lxc/lxc_native.h"
+
+# define VIR_FROM_THIS VIR_FROM_NONE
+
+static int
+blankProblemElements(char *data)
+{
+    if (virtTestClearLineRegex("<uuid>([[:alnum:]]|-)+</uuid>", data) < 0)
+        return -1;
+    return 0;
+}
+
+static int
+testCompareXMLToConfigFiles(const char *xml,
+                            const char *configfile)
+{
+    int ret = -1;
+    char *config = NULL;
+    char *expectxml = NULL;
+    char *actualxml = NULL;
+    virDomainDefPtr vmdef = NULL;
+
+    if (virtTestLoadFile(configfile, &config) < 0)
+        goto fail;
+    if (virtTestLoadFile(xml, &expectxml) < 0)
+        goto fail;
+
+    if (!(vmdef = lxcParseConfigString(config)))
+        goto fail;
+
+    if (!(actualxml = virDomainDefFormat(vmdef, 0)))
+        goto fail;
+
+    if (blankProblemElements(expectxml) < 0 ||
+        blankProblemElements(actualxml) < 0)
+        goto fail;
+
+    if (STRNEQ(expectxml, actualxml)) {
+        virtTestDifference(stderr, expectxml, actualxml);
+        goto fail;
+    }
+
+    ret = 0;
+
+fail:
+    VIR_FREE(expectxml);
+    VIR_FREE(actualxml);
+    VIR_FREE(config);
+    virDomainDefFree(vmdef);
+    return ret;
+}
+
+static int
+testCompareXMLToConfigHelper(const void *data)
+{
+    int result = -1;
+    const char *name = data;
+    char *xml = NULL;
+    char *config = NULL;
+
+    if (virAsprintf(&xml, "%s/lxcconf2xmldata/lxcconf2xml-%s.xml",
+                    abs_srcdir, name) < 0 ||
+        virAsprintf(&config, "%s/lxcconf2xmldata/lxcconf2xml-%s.config",
+                    abs_srcdir, name) < 0)
+        goto cleanup;
+
+    result = testCompareXMLToConfigFiles(xml, config);
+
+cleanup:
+    VIR_FREE(xml);
+    VIR_FREE(config);
+    return result;
+}
+
+static int
+mymain(void)
+{
+    int ret = EXIT_SUCCESS;
+
+# define DO_TEST(name)                                  \
+    if (virtTestRun("LXC Native-2-XML " name,           \
+                    testCompareXMLToConfigHelper,       \
+                    name) < 0)                          \
+        ret = EXIT_FAILURE
+
+    DO_TEST("simple");
+
+    return ret;
+}
+
+VIRT_TEST_MAIN(mymain)
+
+#else
+
+int
+main(void)
+{
+    return EXIT_AM_SKIP;
+}
+
+#endif /* WITH_LXC */