[lxc-devel] [PATCH] c/r: teach criu about cgmanager's socket

[Tycho Andersen]

CRIU needs to be told when something is bind mounted into the container from
the outside as cgmanager's socket is.

Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
---
 src/lxc/cgfs.c         |  1 +
 src/lxc/cgmanager.c    |  1 +
 src/lxc/cgroup.c       |  5 +++++
 src/lxc/cgroup.h       |  7 +++++++
 src/lxc/lxccontainer.c | 16 ++++++++++++++++
 5 files changed, 30 insertions(+)

diff --git a/src/lxc/cgfs.c b/src/lxc/cgfs.c
index 20325fa..11a5925 100644
--- a/src/lxc/cgfs.c
+++ b/src/lxc/cgfs.c
@@ -2403,4 +2403,5 @@ static struct cgroup_ops cgfs_ops = {
 	.chown = NULL,
 	.mount_cgroup = cgroupfs_mount_cgroup,
 	.nrtasks = cgfs_nrtasks,
+	.driver = CGFS,
 };
diff --git a/src/lxc/cgmanager.c b/src/lxc/cgmanager.c
index 0932d96..080e382 100644
--- a/src/lxc/cgmanager.c
+++ b/src/lxc/cgmanager.c
@@ -1396,5 +1396,6 @@ static struct cgroup_ops cgmanager_ops = {
 	.mount_cgroup = cgm_mount_cgroup,
 	.nrtasks = cgm_get_nrtasks,
 	.disconnect = NULL,
+	.driver = CGMANAGER,
 };
 #endif
diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
index a413832..2362ad8 100644
--- a/src/lxc/cgroup.c
+++ b/src/lxc/cgroup.c
@@ -189,3 +189,8 @@ void cgroup_disconnect(void)
 	if (ops && ops->disconnect)
 		ops->disconnect();
 }
+
+cgroup_driver_t cgroup_driver(void)
+{
+	return ops->driver;
+}
diff --git a/src/lxc/cgroup.h b/src/lxc/cgroup.h
index 281f404..6706939 100644
--- a/src/lxc/cgroup.h
+++ b/src/lxc/cgroup.h
@@ -32,6 +32,11 @@ struct lxc_handler;
 struct lxc_conf;
 struct lxc_list;
 
+typedef enum {
+	CGFS,
+	CGMANAGER,
+} cgroup_driver_t;
+
 struct cgroup_ops {
 	const char *name;
 
@@ -51,6 +56,7 @@ struct cgroup_ops {
 	bool (*mount_cgroup)(void *hdata, const char *root, int type);
 	int (*nrtasks)(void *hdata);
 	void (*disconnect)(void);
+	cgroup_driver_t driver;
 };
 
 extern bool cgroup_attach(const char *name, const char *lxcpath, pid_t pid);
@@ -72,5 +78,6 @@ extern const char *cgroup_get_cgroup(struct lxc_handler *handler, const char *su
 extern const char *cgroup_canonical_path(struct lxc_handler *handler);
 extern bool cgroup_unfreeze(struct lxc_handler *handler);
 extern void cgroup_disconnect(void);
+extern cgroup_driver_t cgroup_driver(void);
 
 #endif
diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index c3369cd..d84543f 100644
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -3548,6 +3548,11 @@ static void exec_criu(struct criu_opts *opts)
 		return;
 	}
 
+	// We need to tell criu where cgmanager's socket is bind mounted from
+	// if it exists since it's external.
+	if (cgroup_driver() == CGMANAGER)
+		static_args+=2;
+
 	argv = malloc(static_args * sizeof(*argv));
 	if (!argv)
 		return;
@@ -3590,6 +3595,11 @@ static void exec_criu(struct criu_opts *opts)
 	if (strcmp(opts->action, "dump") == 0) {
 		char pid[32];
 
+		if (cgroup_driver() == CGMANAGER) {
+			DECLARE_ARG("--ext-mount-map");
+			DECLARE_ARG("/sys/fs/cgroup/cgmanager:cgmanager");
+		}
+
 		if (sprintf(pid, "%d", lxcapi_init_pid(opts->c)) < 0)
 			goto err;
 
@@ -3598,6 +3608,12 @@ static void exec_criu(struct criu_opts *opts)
 		if (!opts->stop)
 			DECLARE_ARG("--leave-running");
 	} else if (strcmp(opts->action, "restore") == 0) {
+
+		if (cgroup_driver() == CGMANAGER) {
+			DECLARE_ARG("--ext-mount-map");
+			DECLARE_ARG("cgmanager:/sys/fs/cgroup/cgmanager");
+		}
+
 		DECLARE_ARG("--root");
 		DECLARE_ARG(opts->c->lxc_conf->rootfs.mount);
 		DECLARE_ARG("--restore-detached");
-- 
2.1.0