--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <errno.h>
+#include "test_progs.h"
+#include "cgroup_helpers.h"
+#include "dev_cgroup.skel.h"
+
+#define TEST_CGROUP "/test-bpf-based-device-cgroup/"
+#define TEST_BUFFER_SIZE 64
+
+static void test_mknod(const char *path, mode_t mode, int dev_major,
+                      int dev_minor, int expected_ret, int expected_errno)
+{
+       int ret;
+
+       unlink(path);
+       ret = mknod(path, mode, makedev(dev_major, dev_minor));
+       ASSERT_EQ(ret, expected_ret, "mknod");
+       if (expected_ret)
+               ASSERT_EQ(errno, expected_errno, "mknod errno");
+       else
+               unlink(path);
+}
+
+static void test_read(const char *path, char *buf, int buf_size,
+                     int expected_ret, int expected_errno)
+{
+       int ret, fd;
+
+       fd = open(path, O_RDONLY);
+
+       /* A bare open on unauthorized device should fail */
+       if (expected_ret < 0) {
+               ASSERT_EQ(fd, expected_ret, "open ret for read");
+               ASSERT_EQ(errno, expected_errno, "open errno for read");
+               if (fd >= 0)
+                       close(fd);
+               return;
+       }
+
+       if (!ASSERT_OK_FD(fd, "open ret for read"))
+               return;
+
+       ret = read(fd, buf, buf_size);
+       ASSERT_EQ(ret, expected_ret, "read");
+
+       close(fd);
+}
+
+static void test_write(const char *path, char *buf, int buf_size,
+                      int expected_ret, int expected_errno)
+{
+       int ret, fd;
+
+       fd = open(path, O_WRONLY);
+
+       /* A bare open on unauthorized device should fail */
+       if (expected_ret < 0) {
+               ASSERT_EQ(fd, expected_ret, "open ret for write");
+               ASSERT_EQ(errno, expected_errno, "open errno for write");
+               if (fd >= 0)
+                       close(fd);
+               return;
+       }
+
+       if (!ASSERT_OK_FD(fd, "open ret for write"))
+               return;
+
+       ret = write(fd, buf, buf_size);
+       ASSERT_EQ(ret, expected_ret, "write");
+
+       close(fd);
+}
+
+void test_cgroup_dev(void)
+{
+       char buf[TEST_BUFFER_SIZE] = "some random test data";
+       struct dev_cgroup *skel;
+       int cgroup_fd;
+
+       cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
+       if (!ASSERT_OK_FD(cgroup_fd, "cgroup switch"))
+               return;
+
+       skel = dev_cgroup__open_and_load();
+       if (!ASSERT_OK_PTR(skel, "load program"))
+               goto cleanup_cgroup;
+
+       skel->links.bpf_prog1 =
+               bpf_program__attach_cgroup(skel->progs.bpf_prog1, cgroup_fd);
+       if (!ASSERT_OK_PTR(skel->links.bpf_prog1, "attach_program"))
+               goto cleanup_progs;
+
+       if (test__start_subtest("allow-mknod"))
+               test_mknod("/dev/test_dev_cgroup_null", S_IFCHR, 1, 3, 0, 0);
+
+       if (test__start_subtest("allow-read"))
+               test_read("/dev/urandom", buf, TEST_BUFFER_SIZE,
+                         TEST_BUFFER_SIZE, 0);
+
+       if (test__start_subtest("allow-write"))
+               test_write("/dev/null", buf, TEST_BUFFER_SIZE,
+                          TEST_BUFFER_SIZE, 0);
+
+       if (test__start_subtest("deny-mknod"))
+               test_mknod("/dev/test_dev_cgroup_zero", S_IFCHR, 1, 5, -1,
+                          EPERM);
+
+       if (test__start_subtest("deny-read"))
+               test_read("/dev/random", buf, TEST_BUFFER_SIZE, -1, EPERM);
+
+       if (test__start_subtest("deny-write"))
+               test_write("/dev/zero", buf, TEST_BUFFER_SIZE, -1, EPERM);
+
+cleanup_progs:
+       dev_cgroup__destroy(skel);
+cleanup_cgroup:
+       cleanup_cgroup_environment();
+}
 
+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2017 Facebook
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <assert.h>
-#include <sys/time.h>
-
-#include <linux/bpf.h>
-#include <bpf/bpf.h>
-#include <bpf/libbpf.h>
-
-#include "cgroup_helpers.h"
-#include "testing_helpers.h"
-
-#define DEV_CGROUP_PROG "./dev_cgroup.bpf.o"
-
-#define TEST_CGROUP "/test-bpf-based-device-cgroup/"
-
-int main(int argc, char **argv)
-{
-       struct bpf_object *obj;
-       int error = EXIT_FAILURE;
-       int prog_fd, cgroup_fd;
-       __u32 prog_cnt;
-
-       /* Use libbpf 1.0 API mode */
-       libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
-
-       if (bpf_prog_test_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
-                         &obj, &prog_fd)) {
-               printf("Failed to load DEV_CGROUP program\n");
-               goto out;
-       }
-
-       cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
-       if (cgroup_fd < 0) {
-               printf("Failed to create test cgroup\n");
-               goto out;
-       }
-
-       /* Attach bpf program */
-       if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
-               printf("Failed to attach DEV_CGROUP program");
-               goto err;
-       }
-
-       if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
-                          &prog_cnt)) {
-               printf("Failed to query attached programs");
-               goto err;
-       }
-
-       /* All operations with /dev/null and /dev/urandom are allowed,
-        * everything else is forbidden.
-        */
-       assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
-       assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5"));
-       assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
-
-       /* /dev/null is whitelisted */
-       assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
-       assert(system("mknod /tmp/test_dev_cgroup_null c 1 3") == 0);
-       assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
-
-       assert(system("dd if=/dev/urandom of=/dev/null count=64") == 0);
-
-       /* src is allowed, target is forbidden */
-       assert(system("dd if=/dev/urandom of=/dev/full count=64"));
-
-       /* src is forbidden, target is allowed */
-       assert(system("dd if=/dev/random of=/dev/null count=64"));
-
-       error = 0;
-       printf("test_dev_cgroup:PASS\n");
-
-err:
-       cleanup_cgroup_environment();
-
-out:
-       return error;
-}