From 85dabba53dd65bcf6a5d2df21a19ef9b3fc3ed59 Mon Sep 17 00:00:00 2001
From: Matthias FRANCK <matthias.franck_ext@softathome.com>
Date: Wed, 23 Mar 2022 13:42:48 +0100
Subject: [PATCH] prplOS: procd: LCM: Add patch to fix cgroups mount

Properly mount cgroups in a root tmpfs where every controller is mounted
in a seperate subdirectory, recommended by the kernel documentation of
cgroupsv1.

Signed-off-by: Matthias FRANCK <matthias.franck_ext@softathome.com>
(cherry picked from commit af84ad24a6acd355ec39c8355eccb02e47b3bec6)
---
 ...initd-cgroups-mount-legacy-hierarchy.patch | 61 +++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 package/system/procd/patches/000-initd-cgroups-mount-legacy-hierarchy.patch

diff --git a/package/system/procd/patches/000-initd-cgroups-mount-legacy-hierarchy.patch b/package/system/procd/patches/000-initd-cgroups-mount-legacy-hierarchy.patch
new file mode 100644
index 0000000000..9a14e5c904
--- /dev/null
+++ b/package/system/procd/patches/000-initd-cgroups-mount-legacy-hierarchy.patch
@@ -0,0 +1,61 @@
+--- a/initd/early.c
++++ b/initd/early.c
+@@ -27,6 +27,9 @@
+ #include "../libc-compat.h"
+ #include "../container.h"
+ 
++#define PATH_CGROUP "/sys/fs/cgroup"
++#define PATH_PROC_CGROUPS "/proc/cgroups"
++
+ static void
+ early_dev(void)
+ {
+@@ -53,6 +56,37 @@ early_console(const char *dev)
+ }
+ 
+ static void
++mount_cgroup_controllers(void){
++	char cgroups_line[256] = {0};
++	// Getting supported cgroup controllers from the kernel
++	FILE *filp_cgroups = fopen(PATH_PROC_CGROUPS, "r");
++	if(! filp_cgroups ){
++		ERROR("Failed to open " PATH_PROC_CGROUPS);
++		return;
++	}
++	while( fgets(cgroups_line, 256, filp_cgroups) ){
++		char *space;
++		char fullpath[256] = {0};
++		if(cgroups_line[0] == '#') continue;
++		space = strchr(cgroups_line, '\t');
++		if(! space) continue;
++		*space = '\0';
++
++		if( snprintf(fullpath, 255, PATH_CGROUP "/%s", cgroups_line) < 1){
++			ERROR("Cannot make controller path: %s\n", cgroups_line);
++			continue;
++		}
++		if( mkdir(fullpath, 0777) ){
++			ERROR("Cannot create controller path: %s\n", fullpath);
++			continue;
++		}
++		mount(cgroups_line, fullpath, "cgroup", MS_NOATIME | MS_NODEV | MS_NOEXEC | MS_NOSUID, cgroups_line);
++		LOG("Mounted %s\n", fullpath);
++	}
++	fclose(filp_cgroups);
++}
++
++static void
+ early_mounts(void)
+ {
+ 	unsigned int oldumask = umask(0);
+@@ -60,7 +94,9 @@ early_mounts(void)
+ 	if (!is_container()) {
+ 		mount("proc", "/proc", "proc", MS_NOATIME | MS_NODEV | MS_NOEXEC | MS_NOSUID, 0);
+ 		mount("sysfs", "/sys", "sysfs", MS_NOATIME | MS_NODEV | MS_NOEXEC | MS_NOSUID, 0);
+-		mount("cgroup2", "/sys/fs/cgroup", "cgroup2",  MS_NODEV | MS_NOEXEC | MS_NOSUID | MS_RELATIME, "nsdelegate");
++		LOG("Attempting to mount cgroups (tmpfs + controller subdirs)\n");
++		mount("cgroup2", PATH_CGROUP, "tmpfs", MS_NODEV | MS_NOEXEC | MS_NOSUID, "size=512K");
++		mount_cgroup_controllers();
+ 		mount("tmpfs", "/dev", "tmpfs", MS_NOATIME | MS_NOEXEC | MS_NOSUID, "mode=0755,size=512K");
+ 		ignore(symlink("/tmp/shm", "/dev/shm"));
+ 		mkdir("/dev/pts", 0755);