zdtm: Check threads are restored into correct threaded controllers

This test creates a process with 2 threads in different threaded controllers and
check if CRIU restores these threads' cgroup controllers properly.

Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>

test/zdtm/static/Makefile

@@ -387,6 +387,7 @@ TST_DIR		=				\
 		cgroup03			\
 		cgroup04			\
 		cgroupv2_00			\
+		cgroupv2_01			\
 		cgroup_ifpriomap		\
 		cgroup_ignore			\
 		cgroup_stray			\
@@ -679,6 +680,8 @@ sk-unix-listen02: CFLAGS += -DSK_UNIX_LISTEN02
 sk-unix-listen03: CFLAGS += -DSK_UNIX_LISTEN03
 sk-unix-listen04: CFLAGS += -DSK_UNIX_LISTEN02 -DSK_UNIX_LISTEN03
 
+cgroupv2_01:		LDLIBS += -pthread
+
 $(LIB):	force
 	$(Q) $(MAKE) -C $(LIBDIR)
 

test/zdtm/static/cgroupv2_01.c

@@ -0,0 +1,180 @@
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <pthread.h>
+#include <syscall.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc = "Check that cgroup-v2 threaded controllers";
+const char *test_author = "Bui Quang Minh <minhquangbui99@gmail.com>";
+
+char *dirname;
+TEST_OPTION(dirname, string, "cgroup-v2 directory name", 1);
+const char *cgname = "subcg01";
+
+task_waiter_t t;
+
+#define gettid(code) syscall(__NR_gettid)
+
+void cleanup(void)
+{
+	char path[1024];
+
+	sprintf(path, "%s/%s/%s", dirname, cgname, "thread2");
+	rmdir(path);
+	sprintf(path, "%s/%s/%s", dirname, cgname, "thread1");
+	rmdir(path);
+	sprintf(path, "%s/%s", dirname, cgname);
+	rmdir(path);
+	sprintf(path, "%s", dirname);
+	umount(path);
+}
+
+int is_in_cgroup(char *cgname)
+{
+	FILE *cgf;
+	char buffer[1024];
+
+	sprintf(buffer, "/proc/self/task/%ld/cgroup", gettid());
+	cgf = fopen(buffer, "r");
+	if (cgf == NULL) {
+		pr_err("Fail to open thread's cgroup procfs\n");
+		return 0;
+	}
+
+	while (fgets(buffer, sizeof(buffer), cgf)) {
+		if (strstr(buffer, cgname)) {
+			fclose(cgf);
+			return 1;
+		}
+	}
+
+	fclose(cgf);
+	return 0;
+}
+
+void *thread_func(void *arg)
+{
+	char path[1024], aux[1024];
+
+	sprintf(path, "%s/%s/%s/%s", dirname, cgname, "thread2", "cgroup.threads");
+	sprintf(aux, "%ld", gettid());
+	if (write_value(path, aux)) {
+		cleanup();
+		exit(1);
+	}
+
+	read_value(path, aux, sizeof(aux));
+
+	task_waiter_complete(&t, 1);
+
+	/* Wait for restore */
+	task_waiter_wait4(&t, 2);
+
+	sprintf(path, "/%s/%s", cgname, "thread2");
+	if (!is_in_cgroup(path)) {
+		fail("Thread2's cgroup is not restored");
+		cleanup();
+		exit(1);
+	}
+
+	return NULL;
+}
+
+int main(int argc, char **argv)
+{
+	char path[1024], aux[1024];
+	pthread_t thread2;
+	int ret = 1;
+
+	test_init(argc, argv);
+	task_waiter_init(&t);
+
+	if (mkdir(dirname, 0700) < 0 && errno != EEXIST) {
+		pr_perror("Can't make dir");
+		return -1;
+	}
+
+	if (mount("cgroup2", dirname, "cgroup2", 0, NULL)) {
+		pr_perror("Can't mount cgroup-v2");
+		return -1;
+	}
+
+	sprintf(path, "%s/%s", dirname, cgname);
+	if (mkdir(path, 0700) < 0 && errno != EEXIST) {
+		pr_perror("Can't make dir");
+		goto out;
+	}
+
+	/* Make cpuset controllers available in children directory */
+	sprintf(path, "%s/%s", dirname, "cgroup.subtree_control");
+	sprintf(aux, "%s", "+cpuset");
+	if (write_value(path, aux))
+		goto out;
+
+	sprintf(path, "%s/%s/%s", dirname, cgname, "cgroup.subtree_control");
+	sprintf(aux, "%s", "+cpuset");
+	if (write_value(path, aux))
+		goto out;
+
+	sprintf(path, "%s/%s/%s", dirname, cgname, "cgroup.procs");
+	sprintf(aux, "%d", getpid());
+	if (write_value(path, aux))
+		goto out;
+
+	sprintf(path, "%s/%s/%s", dirname, cgname, "thread1");
+	if (mkdir(path, 0700) < 0 && errno != EEXIST) {
+		pr_perror("Can't make dir");
+		goto out;
+	}
+
+	sprintf(path, "%s/%s/%s/%s", dirname, cgname, "thread1", "cgroup.type");
+	sprintf(aux, "%s", "threaded");
+	if (write_value(path, aux))
+		goto out;
+
+	sprintf(path, "%s/%s/%s", dirname, cgname, "thread2");
+	if (mkdir(path, 0700) < 0 && errno != EEXIST) {
+		pr_perror("Can't make dir");
+		goto out;
+	}
+
+	sprintf(path, "%s/%s/%s/%s", dirname, cgname, "thread2", "cgroup.type");
+	sprintf(aux, "%s", "threaded");
+	if (write_value(path, aux))
+		goto out;
+
+	ret = pthread_create(&thread2, NULL, thread_func, NULL);
+	if (ret < 0) {
+		pr_err("pthread_create %s\n", strerror(ret));
+		ret = 1;
+		goto out;
+	}
+
+	sprintf(path, "%s/%s/%s/%s", dirname, cgname, "thread1", "cgroup.threads");
+	sprintf(aux, "%ld", gettid());
+	if (write_value(path, aux))
+		goto out;
+
+	task_waiter_wait4(&t, 1);
+
+	test_daemon();
+	test_waitsig();
+
+	task_waiter_complete(&t, 2);
+
+	sprintf(path, "/%s/%s", cgname, "thread1");
+	if (!is_in_cgroup(path)) {
+		fail("Main thread's cgroup is not restored");
+		cleanup();
+		exit(1);
+	}
+	pthread_join(thread2, NULL);
+	pass();
+
+	ret = 0;
+
+out:
+	cleanup();
+	return ret;
+}

test/zdtm/static/cgroupv2_01.checkskip

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+if [ -f /sys/fs/cgroup/cgroup.controllers ]; then
+	grep -q "cpuset" /sys/fs/cgroup/cgroup.controllers && exit 0
+fi
+
+if [ -d /sys/fs/cgroup/unified ]; then
+	grep -q "cpuset" /sys/fs/cgroup/unified/cgroup.controllers && exit 0
+fi
+
+exit 1

test/zdtm/static/cgroupv2_01.desc

@@ -0,0 +1 @@
+{'flavor': 'h ns', 'flags': 'suid', 'opts': '--manage-cgroups=full'}

test/zdtm/static/cgroupv2_01.hook

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+[ "$1" == "--clean" -o "$1" == "--pre-restore" ] || exit 0
+
+set -e
+cgname="subcg01"
+tname=$(mktemp -d cgclean.XXXXXX)
+mount -t cgroup2 cgroup2 $tname
+
+echo "Cleaning $tname"
+
+set +e
+rmdir "$tname/$cgname/thread1"
+
+# When the test finishes, the cleanup() function removes this directory
+# successfully because the thread in this controller exit and no other
+# threads belong to this controller
+if [ "$1" == "--pre-restore" ]; then
+	rmdir "$tname/$cgname/thread2"
+fi
+
+rmdir "$tname/$cgname"
+umount "$tname"
+rmdir "$tname"