diff --git a/src/cgroup.c b/src/cgroup.c
index b7491ba..ebe8c94 100644
--- a/src/cgroup.c
+++ b/src/cgroup.c
@@ -36,10 +36,10 @@
  * TODO:
  * Add more cgroups support.
  */
-static void mount_cgroup_v1_memory(void)
+static void mount_cgroup_v1(const char *_Nonnull controller)
 {
 	/*
-	 * Mount Cgroup v1 memory controller.
+	 * Mount Cgroup v1 _any_ controller.
 	 * Nothing to return because if this function run failed,
 	 * that means cgroup is fully not supported on the device.
 	 */
@@ -49,46 +49,12 @@ static void mount_cgroup_v1_memory(void)
 	// Mount /sys/fs/cgroup as tmpfs.
 	mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, NULL);
 	// Mount memory controller.
-	mkdir("/sys/fs/cgroup/memory", S_IRUSR | S_IWUSR);
+	char cgroup_controller_path[PATH_MAX] = { '\0' };
+	sprintf(cgroup_controller_path, "/sys/fs/cgroup/%s", controller);
+	mkdir(cgroup_controller_path, S_IRUSR | S_IWUSR);
 	usleep(2000);
-	mount("none", "/sys/fs/cgroup/memory", "cgroup", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, "memory");
-	ruri_log("{base}Tried to mount cgroup v1 memory\n");
-}
-static void mount_cgroup_v1_cpu(void)
-{
-	/*
-	 * Mount Cgroup v1 cpu controller.
-	 * Nothing to return because if this function run failed,
-	 * that means cgroup is fully not supported on the device.
-	 */
-	mkdir("/sys/fs/cgroup", S_IRUSR | S_IWUSR);
-	// Maybe needless.
-	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
-	// Mount /sys/fs/cgroup as tmpfs.
-	mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, NULL);
-	// Mount cpu controller.
-	mkdir("/sys/fs/cgroup/cpu", S_IRUSR | S_IWUSR);
-	usleep(2000);
-	mount("none", "/sys/fs/cgroup/cpu", "cgroup", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, "cpu");
-	ruri_log("{base}Tried to mount cgroup v1 cpu\n");
-}
-static void mount_cgroup_v1_cpuset(void)
-{
-	/*
-	 * Mount Cgroup v1 cpuset controller.
-	 * Nothing to return because if this function run failed,
-	 * that means cgroup is fully not supported on the device.
-	 */
-	mkdir("/sys/fs/cgroup", S_IRUSR | S_IWUSR);
-	// Maybe needless.
-	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
-	// Mount /sys/fs/cgroup as tmpfs.
-	mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, NULL);
-	// Mount cpuset controller.
-	mkdir("/sys/fs/cgroup/cpuset", S_IRUSR | S_IWUSR);
-	usleep(2000);
-	mount("none", "/sys/fs/cgroup/cpuset", "cgroup", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, "cpuset");
-	ruri_log("{base}Tried to mount cgroup v1 cpuset\n");
+	mount("none", cgroup_controller_path, "cgroup", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, controller);
+	ruri_log("{base}Tried to mount cgroup v1 %s\n", controller);
 }
 static bool is_cgroupv2_support(const char *_Nonnull type)
 {
@@ -111,10 +77,11 @@ static bool is_cgroupv2_support(const char *_Nonnull type)
 	write(subtree_control_fd, "+cpuset\n", strlen("+cpuset\n"));
 	close(subtree_control_fd);
 	usleep(200);
-	// Check if we have a controlable cgroup for `type`.
+	// Check if we have a controllable cgroup for `type`.
 	mkdir("/sys/fs/cgroup/ruri", S_IRUSR | S_IWUSR);
 	int fd = open("/sys/fs/cgroup/ruri/cgroup.controllers", O_RDONLY | O_CLOEXEC);
 	if (fd < 0) {
+		rmdir("/sys/fs/cgroup/ruri");
 		umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 		ruri_log("{base}Cgroup v2 does not support %s\n", type);
 		ruri_log("{base}cgroup.controllers does not exist\n");
@@ -124,12 +91,7 @@ static bool is_cgroupv2_support(const char *_Nonnull type)
 	ssize_t len = read(fd, buf, 255);
 	if (len <= 0) {
 		close(fd);
-		umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
-		ruri_log("{base}Cgroup v2 does not support %s\n", type);
-		ruri_log("{base}cgroup.controllers read failed\n");
-		return false;
-	}
-	if (len <= 0) {
+		rmdir("/sys/fs/cgroup/ruri");
 		umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 		ruri_log("{base}Cgroup v2 does not support %s\n", type);
 		ruri_log("{base}cgroup.controllers read failed\n");
@@ -143,10 +105,12 @@ static bool is_cgroupv2_support(const char *_Nonnull type)
 	// If str_to_find is in buf and str_to_find+1 is space (' ') or end ('\0').
 	// We return true.
 	if (strstr(buf, str_to_find) != NULL && (strstr(buf, str_to_find)[strlen(str_to_find)] == ' ' || strstr(buf, str_to_find)[strlen(str_to_find)] == '\0')) {
+		rmdir("/sys/fs/cgroup/ruri");
 		umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 		ruri_log("{base}Cgroup v2 supports %s\n", type);
 		return true;
 	}
+	rmdir("/sys/fs/cgroup/ruri");
 	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 	ruri_log("{base}Cgroup v2 does not support %s\n", type);
 	return false;
@@ -178,6 +142,60 @@ static char *memory_to_bytes(const char *_Nonnull memory)
 	free(memory_dup);
 	return ret;
 }
+// Returns 1 for failed open(). //FIXME WIP
+static int cgroup_v1_attach(const struct RURI_CONTAINER *_Nonnull container, const char *_Nonnull controller)
+{
+	pid_t pid = getpid();
+	char buf[128] = { '\0' };
+	char cgroup_path[PATH_MAX] = { '\0' };
+	sprintf(memory_cgroup_path, "/sys/fs/cgroup/%s/%d", controller, container->container_id);
+	mkdir(memory_cgroup_path, S_IRUSR | S_IWUSR);
+	usleep(200);
+	int fd = -1;
+	if (container->memory != NULL) {
+		// Set memory limit.
+		char memory_cgroup_limit_path[PATH_MAX] = { '\0' };
+		sprintf(memory_cgroup_limit_path, "/sys/fs/cgroup/memory/%d/memory.limit_in_bytes", container->container_id);
+		fd = open(memory_cgroup_limit_path, O_RDWR | O_CLOEXEC);
+		if (fd < 0 && !container->no_warnings) {
+			ruri_warning("{yellow}Set memory limit failed{clear}\n");
+			umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
+			return;
+		}
+		char *memory = memory_to_bytes(container->memory);
+		sprintf(buf, "%s\n", memory);
+		if (write(fd, buf, strlen(buf)) < 0 && !container->no_warnings) {
+			ruri_warning("{yellow}Set memory limit failed{clear}\n");
+		}
+		free(memory);
+		close(fd);
+		char memory_oom[PATH_MAX] = { '\0' };
+		sprintf(memory_oom, "/sys/fs/cgroup/memory/%d/memory.oom_control", container->container_id);
+		fd = open(memory_oom, O_RDWR | O_CLOEXEC);
+		if (fd < 0 && !container->no_warnings) {
+			ruri_warning("{yellow}Set memory limit failed{clear}\n");
+			umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
+			return;
+		}
+		sprintf(buf, "1\n");
+		if (write(fd, buf, strlen(buf)) < 0 && !container->no_warnings) {
+			ruri_warning("{yellow}Set memory limit failed{clear}\n");
+		}
+		close(fd);
+	}
+	char memory_cgroup_procs_path[PATH_MAX] = { '\0' };
+	sprintf(memory_cgroup_procs_path, "/sys/fs/cgroup/memory/%d/cgroup.procs", container->container_id);
+	// Add pid to container_id memory cgroup.
+	fd = open(memory_cgroup_procs_path, O_RDWR | O_CLOEXEC);
+	if (fd < 0) {
+		umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
+		return;
+	}
+	sprintf(buf, "%d\n", pid);
+	write(fd, buf, strlen(buf));
+	close(fd);
+	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
+}
 static void set_cgroup_v1_memory(const struct RURI_CONTAINER *_Nonnull container)
 {
 	/*
@@ -186,7 +204,8 @@ static void set_cgroup_v1_memory(const struct RURI_CONTAINER *_Nonnull container
 	 * Control file:
 	 * /sys/fs/cgroup/memory/${container_id}/memory.limit_in_bytes
 	 */
-	mount_cgroup_v1_memory();
+	mount_cgroup_v1("memory");
+
 	pid_t pid = getpid();
 	char buf[128] = { '\0' };
 	char memory_cgroup_path[PATH_MAX] = { '\0' };
@@ -247,7 +266,7 @@ static void set_cgroup_v1_cpu(const struct RURI_CONTAINER *_Nonnull container)
 	 * /sys/fs/cgroup/cpu/${container_id}/cpu.cfs_quota_us
 	 * /sys/fs/cgroup/cpu/${container_id}/cpu.cfs_period_us
 	 */
-	mount_cgroup_v1_cpu();
+	mount_cgroup_v1("cpu");
 	char cpu_cgroup_path[PATH_MAX] = { '\0' };
 	sprintf(cpu_cgroup_path, "/sys/fs/cgroup/cpu/%d", container->container_id);
 	mkdir(cpu_cgroup_path, S_IRUSR | S_IWUSR);
@@ -304,7 +323,7 @@ static void set_cgroup_v1_cpuset(const struct RURI_CONTAINER *_Nonnull container
 	 * Nothing to return, only warnings to show if cgroup is not supported.
 	 * Control file: /sys/fs/cgroup/cpuset/${container_id}/cpuset.cpus
 	 */
-	mount_cgroup_v1_cpuset();
+	mount_cgroup_v1("cpuset");
 	char cpuset_cgroup_path[PATH_MAX] = { '\0' };
 	sprintf(cpuset_cgroup_path, "/sys/fs/cgroup/cpuset/%d", container->container_id);
 	mkdir(cpuset_cgroup_path, S_IRUSR | S_IWUSR);
@@ -354,6 +373,31 @@ static void set_cgroup_v1_cpuset(const struct RURI_CONTAINER *_Nonnull container
 	// Do not keep the apifs mounted.
 	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 }
+// Returns 1 for failed open().
+static int cgroup_v2_attach(const struct RURI_CONTAINER *_Nonnull container)
+{
+	pid_t pid = getpid();
+	char buf[128] = { '\0' };
+	char cgroup_path[PATH_MAX] = { '\0' };
+	sprintf(cgroup_path, "/sys/fs/cgroup/%d", container->container_id);
+	mkdir(cgroup_path, S_IRUSR | S_IWUSR);
+	usleep(200);
+	// Add pid to container_id cgroup.
+	char cgroup_procs_path[PATH_MAX] = { '\0' };
+	sprintf(cgroup_procs_path, "/sys/fs/cgroup/%d/cgroup.procs", container->container_id);
+	int fd = open(cgroup_procs_path, O_RDWR | O_CLOEXEC);
+	if (fd < 0 && !container->no_warnings) {
+		ruri_warning("{yellow}Set cgroup.procs failed{clear}\n");
+		// Report failure for apifs cleanup
+		return 1;
+	}
+	sprintf(buf, "%d\n", pid);
+	if (write(fd, buf, strlen(buf)) < 0 && !container->no_warnings) {
+		ruri_warning("{yellow}Set cgroup.procs failed{clear}\n");
+	}
+	close(fd);
+	return 0;
+}
 static void set_cgroup_v2_memory(const struct RURI_CONTAINER *_Nonnull container)
 {
 	/*
@@ -366,36 +410,24 @@ static void set_cgroup_v2_memory(const struct RURI_CONTAINER *_Nonnull container
 	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 	// Mount /sys/fs/cgroup as cgroup2.
 	mount("none", "/sys/fs/cgroup", "cgroup2", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, NULL);
-	pid_t pid = getpid();
-	char buf[128] = { '\0' };
-	char cgroup_path[PATH_MAX] = { '\0' };
-	sprintf(cgroup_path, "/sys/fs/cgroup/%d", container->container_id);
-	mkdir(cgroup_path, S_IRUSR | S_IWUSR);
-	usleep(200);
-	char cgroup_procs_path[PATH_MAX] = { '\0' };
-	sprintf(cgroup_procs_path, "/sys/fs/cgroup/%d/cgroup.procs", container->container_id);
 	// Add pid to container_id cgroup.
-	int fd = open(cgroup_procs_path, O_RDWR | O_CLOEXEC);
-	if (fd < 0 && !container->no_warnings) {
-		ruri_warning("{yellow}Set cgroup.procs failed{clear}\n");
+	if (cgroup_v2_attach(container)) {
 		// Do not keep the apifs mounted.
 		umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 		return;
 	}
-	sprintf(buf, "%d\n", pid);
-	write(fd, buf, strlen(buf));
-	close(fd);
 	if (container->memory != NULL) {
 		// Set memory limit.
 		char cgroup_memlimit_path[PATH_MAX] = { '\0' };
 		sprintf(cgroup_memlimit_path, "/sys/fs/cgroup/%d/memory.high", container->container_id);
-		fd = open(cgroup_memlimit_path, O_RDWR | O_CLOEXEC);
+		int fd = open(cgroup_memlimit_path, O_RDWR | O_CLOEXEC);
 		if (fd < 0 && !container->no_warnings) {
 			ruri_warning("{yellow}Set memory limit failed{clear}\n");
 			// Do not keep the apifs mounted.
 			umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 			return;
 		}
+		char buf[256] = { '\0' };
 		sprintf(buf, "%s\n", container->memory);
 		if (write(fd, buf, strlen(buf)) < 0 && !container->no_warnings) {
 			ruri_warning("{yellow}Set memory limit failed{clear}\n");
@@ -444,38 +476,24 @@ static void set_cgroup_v2_cpuset(const struct RURI_CONTAINER *_Nonnull container
 	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 	// Mount /sys/fs/cgroup as cgroup2.
 	mount("none", "/sys/fs/cgroup", "cgroup2", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, NULL);
-	pid_t pid = getpid();
-	char buf[128] = { '\0' };
-	char cgroup_path[PATH_MAX] = { '\0' };
-	sprintf(cgroup_path, "/sys/fs/cgroup/%d", container->container_id);
-	mkdir(cgroup_path, S_IRUSR | S_IWUSR);
-	usleep(200);
-	char cgroup_procs_path[PATH_MAX] = { '\0' };
-	sprintf(cgroup_procs_path, "/sys/fs/cgroup/%d/cgroup.procs", container->container_id);
 	// Add pid to container_id cgroup.
-	int fd = open(cgroup_procs_path, O_RDWR | O_CLOEXEC);
-	if (fd < 0 && !container->no_warnings) {
-		ruri_warning("{yellow}Set cgroup.procs failed{clear}\n");
+	if (cgroup_v2_attach(container)) {
 		// Do not keep the apifs mounted.
 		umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 		return;
 	}
-	sprintf(buf, "%d\n", pid);
-	if (write(fd, buf, strlen(buf)) < 0 && !container->no_warnings) {
-		ruri_warning("{yellow}Set cgroup.procs failed{clear}\n");
-	}
-	close(fd);
 	if (container->cpuset != NULL) {
 		// Set cpuset limit.
 		char cgroup_cpuset_path[PATH_MAX] = { '\0' };
 		sprintf(cgroup_cpuset_path, "/sys/fs/cgroup/%d/cpuset.cpus", container->container_id);
-		fd = open(cgroup_cpuset_path, O_RDWR | O_CLOEXEC);
+		int fd = open(cgroup_cpuset_path, O_RDWR | O_CLOEXEC);
 		if (fd < 0 && !container->no_warnings) {
 			ruri_warning("{yellow}Set cpuset limit failed{clear}\n");
 			// Do not keep the apifs mounted.
 			umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 			return;
 		}
+		char buf[256] = { '\0' };
 		sprintf(buf, "%s\n", container->cpuset);
 		if (write(fd, buf, strlen(buf)) < 0 && !container->no_warnings) {
 			ruri_warning("{yellow}Set cpuset limit failed{clear}\n");
@@ -497,38 +515,24 @@ static void set_cgroup_v2_cpu(const struct RURI_CONTAINER *_Nonnull container)
 	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 	// Mount /sys/fs/cgroup as cgroup2.
 	mount("none", "/sys/fs/cgroup", "cgroup2", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, NULL);
-	pid_t pid = getpid();
-	char buf[128] = { '\0' };
-	char cgroup_path[PATH_MAX] = { '\0' };
-	sprintf(cgroup_path, "/sys/fs/cgroup/%d", container->container_id);
-	mkdir(cgroup_path, S_IRUSR | S_IWUSR);
-	usleep(200);
-	char cgroup_procs_path[PATH_MAX] = { '\0' };
-	sprintf(cgroup_procs_path, "/sys/fs/cgroup/%d/cgroup.procs", container->container_id);
 	// Add pid to container_id cgroup.
-	int fd = open(cgroup_procs_path, O_RDWR | O_CLOEXEC);
-	if (fd < 0 && !container->no_warnings) {
-		ruri_warning("{yellow}Set cgroup.procs failed{clear}\n");
+	if (cgroup_v2_attach(container)) {
 		// Do not keep the apifs mounted.
 		umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 		return;
 	}
-	sprintf(buf, "%d\n", pid);
-	if (write(fd, buf, strlen(buf)) < 0 && !container->no_warnings) {
-		ruri_warning("{yellow}Set cgroup.procs failed{clear}\n");
-	}
-	close(fd);
 	if (container->cpupercent > 0) {
 		// Set cpuset limit.
 		char cgroup_cpu_path[PATH_MAX] = { '\0' };
 		sprintf(cgroup_cpu_path, "/sys/fs/cgroup/%d/cpu.max", container->container_id);
-		fd = open(cgroup_cpu_path, O_RDWR | O_CLOEXEC);
+		int fd = open(cgroup_cpu_path, O_RDWR | O_CLOEXEC);
 		if (fd < 0 && !container->no_warnings) {
 			ruri_warning("{yellow}Set cpupercent limit failed{clear}\n");
 			// Do not keep the apifs mounted.
 			umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 			return;
 		}
+		char buf[256] = { '\0' };
 		sprintf(buf, "%d 100000\n", container->cpupercent * 1000);
 		if (write(fd, buf, strlen(buf)) < 0 && !container->no_warnings) {
 			ruri_warning("{yellow}Set cpupercent limit failed{clear}\n");
@@ -538,6 +542,23 @@ static void set_cgroup_v2_cpu(const struct RURI_CONTAINER *_Nonnull container)
 	// Do not keep the apifs mounted.
 	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
 }
+void ruri_attach_cgroup_v2(const struct RURI_CONTAINER *_Nonnull container)
+{
+	/*
+	 * Mount cgroupv2 hierarchy and attach process.
+	 * Nothing to return, only warnings to show if cgroup is not supported.
+	 * Control file: /sys/fs/cgroup/${container_id}/cgroup.procs
+	 */
+	mkdir("/sys/fs/cgroup", S_IRUSR | S_IWUSR);
+	// Maybe needless.
+	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
+	// Mount /sys/fs/cgroup as cgroup2.
+	mount("none", "/sys/fs/cgroup", "cgroup2", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, NULL);
+	// Add pid to container_id cgroup.
+	cgroup_v2_attach(container);
+	// Do not keep the apifs mounted.
+	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
+}
 void ruri_set_limit(const struct RURI_CONTAINER *_Nonnull container)
 {
 	/*
@@ -568,3 +589,43 @@ void ruri_set_limit(const struct RURI_CONTAINER *_Nonnull container)
 		mount("tmpfs", "/sys/fs", "tmpfs", MS_RDONLY, NULL);
 	}
 }
+void ruri_kill_container_with_cgroup_v2(const struct RURI_CONTAINER *_Nonnull container)
+{
+	/*
+	 * Kill all processes in corresponding cgroup v2 structure.
+	 * FIXME what should i return?
+	 */
+	// Umount the mask of /sys/fs
+	if (!container->unmask_dirs) {
+		umount2("/sys/fs", MNT_DETACH | MNT_FORCE);
+	}
+	if (!is_cgroupv2_support("kill")) {
+		; // FIXME
+	}
+	mkdir("/sys/fs/cgroup", S_IRUSR | S_IWUSR);
+	// Maybe needless.
+	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
+	// Mount /sys/fs/cgroup as cgroup2.
+	mount("none", "/sys/fs/cgroup", "cgroup2", MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME, NULL);
+	char cgroup_path[PATH_MAX] = { '\0' };
+	sprintf(cgroup_path, "/sys/fs/cgroup/%d", container->container_id);
+	// FIXME detect dir existence instead of mkdir
+	usleep(200);
+	char cgroup_kill_path[PATH_MAX] = { '\0' };
+	sprintf(cgroup_kill_path, "/sys/fs/cgroup/%d/cgroup.kill", container->container_id);
+	// Pid should be added beforehand.
+	int fd = open(cgroup_kill_path, O_RDWR | O_CLOEXEC);
+	if ((fd < 0 || write(fd, "1\n", strlen("1\n")) < 0) && !container->no_warnings) {
+		ruri_warning("{yellow}Set cgroup.procs failed{clear}\n");
+	}
+	if (fd < 0) {
+		close(fd);
+	}
+	// Do not keep the apifs mounted.
+	umount2("/sys/fs/cgroup", MNT_DETACH | MNT_FORCE);
+	// Mask /sys/fs again.
+	if (!container->unmask_dirs) {
+		mount("tmpfs", "/sys/fs", "tmpfs", MS_RDONLY, NULL);
+	}
+}
+// TODO void container_ps_with_cgroup_v2(const