From: Mike Yuan <me@yhndnzj.com>
Date: Fri, 29 Nov 2024 16:13:18 +0000 (+0100)
Subject: cgroup-util: explain why cg_pidref_get_path() cannot be ported over to pidfd helpers... 
X-Git-Tag: v258-rc1~1704^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F35242%2Fhead;p=thirdparty%2Fsystemd.git

cgroup-util: explain why cg_pidref_get_path() cannot be ported over to pidfd helpers (yet)

See also: https://github.com/systemd/systemd/pull/35242#issuecomment-2506686806
---

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index 50f1f0e4df2..1d2faa7393f 100644
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -861,6 +861,10 @@ int cg_pidref_get_path(const char *controller, const PidRef *pidref, char **ret_
         if (!pidref_is_set(pidref))
                 return -ESRCH;
 
+        // XXX: Ideally we'd use pidfd_get_cgroupid() + cg_path_from_cgroupid() here, to extract this
+        // bit of information from pidfd directly. However, the latter requires privilege and it's
+        // not entirely clear how to handle cgroups from outer namespace.
+
         r = cg_pid_get_path(controller, pidref->pid, &path);
         if (r < 0)
                 return r;