From 23b3d0e2a69287673431925987497ac64964595b Mon Sep 17 00:00:00 2001
From: Kunhoon Baik <knhoon.baik@samsung.com>
Date: Mon, 6 Sep 2021 16:41:04 +0900
Subject: [PATCH] Add cgroup_remount program for target using old-resourced

Old Tizen resourced used "resourced" cgroup folder for controlling memory instead of "memory"
To apply nsjail(+malort) for such target, memory folder should be created.

For the compatibility, cgroup_mount is provided.

cf) provide mount prgoram because some targets cannot use mount program freely.
---
 Makefile              |  6 +++-
 cgroup_remount.cc     | 76 +++++++++++++++++++++++++++++++++++++++++++
 packaging/nsjail.sh   |  6 ++++
 packaging/nsjail.spec |  2 ++
 4 files changed, 89 insertions(+), 1 deletion(-)
 create mode 100644 cgroup_remount.cc

diff --git a/Makefile b/Makefile
index 7722452..cb22a93 100644
--- a/Makefile
+++ b/Makefile
@@ -59,7 +59,11 @@ endif
 .cc.o: %.cc
 	$(CXX) $(CXXFLAGS) $< -o $@
 
-all: $(BIN)
+all: $(BIN) cgroup_remount
+
+cgroup_remount :
+	$(CXX) $(CXXFLAGS) cgroup_remount.cc -o cgroup_remount.o
+	$(CXX) -o cgroup_remount cgroup_remount.o $(LDFLAGS)
 
 $(BIN): $(LIBS) $(OBJS)
 ifneq ($(NL3_EXISTS), yes)
diff --git a/cgroup_remount.cc b/cgroup_remount.cc
new file mode 100644
index 0000000..6534fac
--- /dev/null
+++ b/cgroup_remount.cc
@@ -0,0 +1,76 @@
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mount.h>
+
+#define DEFAULT_CGROUP	"/sys/fs/cgroup"
+#define MAX_PATH_LENGTH	512
+
+static bool cgroup_is_exists(const char *cgroup_full_path)
+{
+	struct stat stat_buf;
+	return stat(cgroup_full_path, &stat_buf) == 0;
+}
+
+int cgroup_make_subdir(const char* parentdir, const char* new_name, const char* target_name)
+{
+	char buf[MAX_PATH_LENGTH];
+	char new_buf[MAX_PATH_LENGTH];
+	bool cgroup_exists;
+	bool cgroup_remount = false;
+	int ret = 0;
+
+	if (!parentdir || !new_name || !target_name) 
+		return -1;
+
+	snprintf(buf, sizeof(buf), "%s/%s", parentdir, target_name);
+	snprintf(new_buf, sizeof(new_buf), "%s/%s", parentdir, new_name);
+
+	cgroup_exists = cgroup_is_exists(new_buf);
+	if (!cgroup_exists) {
+		if (!strncmp(parentdir, DEFAULT_CGROUP, sizeof(DEFAULT_CGROUP))) {
+			ret = mount("tmpfs", DEFAULT_CGROUP, "tmpfs",
+					MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, "mode=755");
+			if (ret < 0){ 
+				printf("rw remount failed\n");
+				return -1;
+			}
+			cgroup_remount = true;
+		}
+
+		ret = symlink(buf, new_buf);
+		if(ret < 0){
+			printf("symlink failed\n");
+			return -1;
+		}
+
+		if (cgroup_remount) {
+			ret = mount("tmpfs", DEFAULT_CGROUP, "tmpfs",
+					MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755");
+			if (ret < 0){
+				printf("ro remount failed\n");
+				return -1;
+			}
+		}
+	}
+	else
+		printf("the cgroup is already existed\n");
+
+	return 0;
+}
+
+int main()
+{
+	int ret;
+	ret = cgroup_make_subdir(DEFAULT_CGROUP, "memory", "resourced");
+	if (ret < 0)
+		printf("creation failed\n");
+	else
+		printf("creation success or already created\n");
+	return ret;
+}
+
diff --git a/packaging/nsjail.sh b/packaging/nsjail.sh
index 89d6068..a74456e 100644
--- a/packaging/nsjail.sh
+++ b/packaging/nsjail.sh
@@ -5,6 +5,12 @@ OWNER_ID=`id -u owner`
 
 if [ x$1 == "xstart" ]
 then
+	while [ ! -d "/sys/fs/cgroup/memory" ]
+	do
+		/usr/bin/cgroup_remount
+		sleep 1;
+	done
+
 	mkdir /sys/fs/cgroup/memory/malort
 	chown -R owner:users /sys/fs/cgroup/memory/malort
 
diff --git a/packaging/nsjail.spec b/packaging/nsjail.spec
index 1957a34..e9e7c81 100644
--- a/packaging/nsjail.spec
+++ b/packaging/nsjail.spec
@@ -60,6 +60,7 @@ mkdir -p %{buildroot}/usr/share/
 mkdir -p %{buildroot}/%{_unitdir}
 
 install -m 0755 nsjail %{buildroot}/%{_bindir}/
+install -m 0755 cgroup_remount %{buildroot}/%{_bindir}/
 install -m 0755 nsjail.sh %{buildroot}/%{_bindir}/
 install -m 0644 nsjail.service %{buildroot}/%{_unitdir}/
 %install_service multi-user.target.wants nsjail.service
@@ -71,6 +72,7 @@ cp -a test/*.cfg %{buildroot}/usr/share/
 %manifest %{name}.manifest
 %license LICENSE
 %{_bindir}/nsjail*
+%{_bindir}/cgroup_remount*
 %{_unitdir}/nsjail.service
 %{_unitdir}/multi-user.target.wants/nsjail.service
 
-- 
2.34.1