add function linuxnamespaces.populate_sys

1 files changed, 5 insertions, 22 deletions

diff --git a/examples/cgroup.py b/examples/cgroup.py
index 0c52efb..baacf35 100755
--- a/examples/cgroup.py
+++ b/examples/cgroup.py
@@ -78,17 +78,16 @@ def start_transient_unit_with_ravel(pid: int) -> None:
 
 def main() -> None:
     mycgroup = get_cgroup()
-    mycgroupdir = pathlib.Path("/sys/fs/cgroup") / mycgroup.relative_to("/")
-    if not os.access(mycgroupdir, os.W_OK):
+    if not os.access(
+        pathlib.Path("/sys/fs/cgroup") / mycgroup.relative_to("/"),
+        os.W_OK,
+    ):
         # For some shells - notably from graphical desktop environments, the
         # hiearchy is immediatly writeable. For others, we may create a scope
         # unit.
         if ravel is not None:
             start_transient_unit_with_ravel(os.getpid())
             mycgroup = get_cgroup()
-            mycgroupdir = pathlib.Path(
-                "/sys/fs/cgroup"
-            ) / mycgroup.relative_to("/")
         else:
             # Re-execute ourselves via systemd-run.
             if (
@@ -111,23 +110,7 @@ def main() -> None:
         | linuxnamespaces.CloneFlags.NEWNS
         | linuxnamespaces.CloneFlags.NEWCGROUP,
     )
-    cgroupfd = linuxnamespaces.open_tree(
-        mycgroupdir,
-        linuxnamespaces.OpenTreeFlags.OPEN_TREE_CLONE
-        | linuxnamespaces.OpenTreeFlags.AT_RECURSIVE,
-    )
-    linuxnamespaces.mount("tmpfs", "/sys", "tmpfs", data="mode=0755")
-    os.mkdir("/sys/fs")
-    os.mkdir("/sys/fs/cgroup")
-    linuxnamespaces.mount(
-        "tmpfs",
-        "/sys",
-        "tmpfs", 
-        linuxnamespaces.MountFlags.fromstr("remount,ro,noexec,nosuid,nodev"),
-        "mode=0755",
-    )
-    linuxnamespaces.move_mount(cgroupfd, "/sys/fs/cgroup")
-    cgroupfd.close()
+    linuxnamespaces.populate_sys("/", "/", mycgroup)
     os.execlp(os.environ["SHELL"], os.environ["SHELL"])