If the ns_cgroup does not exist, we use the clone_children feature.
Everytime a cgroup is created, we set this compatibility flag and we create
the cgroup manually and add the child task to the cgroup.
Signed-off-by: Daniel Lezcano <daniel.lezc...@free.fr>
---
src/lxc/cgroup.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 74 insertions(+), 1 deletions(-)
diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
index b711c64..1c603fc 100644
--- a/src/lxc/cgroup.c
+++ b/src/lxc/cgroup.c
@@ -101,10 +101,56 @@ int lxc_rename_nsgroup(const char *mnt, const char *name,
pid_t pid)
return 0;
}
+static int cgroup_enable_clone_children(const char *path)
+{
+ FILE *f;
+ int ret = 0;
+
+ f = fopen(path, "w");
+ if (!f) {
+ SYSERROR("failed to open '%s'", path);
+ return -1;
+ }
+
+ if (fprintf(f, "1") < 1) {
+ ERROR("failed to write flag to '%s'", path);
+ ret = -1;
+ }
+
+ fclose(f);
+
+ return ret;
+}
+
+static int cgroup_attach(const char *path, pid_t pid)
+{
+ FILE *f;
+ char tasks[MAXPATHLEN];
+ int ret = 0;
+
+ snprintf(tasks, MAXPATHLEN, "%s/tasks", path);
+
+ f = fopen(tasks, "w");
+ if (!f) {
+ SYSERROR("failed to open '%s'", tasks);
+ return -1;
+ }
+
+ if (fprintf(f, "%d", pid) <= 0) {
+ SYSERROR("failed to write pid '%d' to '%s'", pid, tasks);
+ ret = -1;
+ }
+
+ fclose(f);
+
+ return ret;
+}
+
int lxc_cgroup_create(const char *name, pid_t pid)
{
char cgmnt[MAXPATHLEN];
char cgname[MAXPATHLEN];
+ char clonechild[MAXPATHLEN];
if (get_cgroup_mount(MTAB, cgmnt)) {
ERROR("cgroup is not mounted");
@@ -122,7 +168,34 @@ int lxc_cgroup_create(const char *name, pid_t pid)
return -1;
}
- return lxc_rename_nsgroup(cgmnt, cgname, pid);
+ snprintf(clonechild, MAXPATHLEN, "%s/cgroup.clone_children", cgmnt);
+
+ /* we check if the kernel has ns_cgroup or clone_children */
+ if (access(clonechild, F_OK)) {
+ WARN("using deprecated ns_cgroup");
+ return lxc_rename_nsgroup(cgmnt, cgname, pid);
+ }
+
+ /* we enable the clone_children flag of the cgroup */
+ if (cgroup_enable_clone_children(clonechild)) {
+ SYSERROR("failed to enable 'clone_children flag");
+ return -1;
+ }
+
+ /* Let's create the cgroup */
+ if (mkdir(cgname, 0700)) {
+ SYSERROR("failed to create '%s' directory", cgname);
+ return -1;
+ }
+
+ /* Let's add the pid to the 'tasks' file */
+ if (cgroup_attach(cgname, pid)) {
+ SYSERROR("failed to attach pid '%d' to '%s'", pid, cgname);
+ rmdir(cgname);
+ return -1;
+ }
+
+ return 0;
}
int lxc_cgroup_destroy(const char *name)
--
1.7.0.4
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