pinning_devmap_reuse.c

 1// SPDX-License-Identifier: GPL-2.0
 2
 3#include <sys/types.h>
 4#include <sys/stat.h>
 5#include <unistd.h>
 6#include <test_progs.h>
 7
 8
 9#include "test_pinning_devmap.skel.h"
10
11void test_pinning_devmap_reuse(void)
12{
13	const char *pinpath1 = "/sys/fs/bpf/pinmap1";
14	const char *pinpath2 = "/sys/fs/bpf/pinmap2";
15	struct test_pinning_devmap *skel1 = NULL, *skel2 = NULL;
16	int err;
17	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
18
19	/* load the object a first time */
20	skel1 = test_pinning_devmap__open_and_load();
21	if (!ASSERT_OK_PTR(skel1, "skel_load1"))
22		goto out;
23
24	/* load the object a second time, re-using the pinned map */
25	skel2 = test_pinning_devmap__open_and_load();
26	if (!ASSERT_OK_PTR(skel2, "skel_load2"))
27		goto out;
28
29	/* we can close the reference safely without
30	 * the map's refcount falling to 0
31	 */
32	test_pinning_devmap__destroy(skel1);
33	skel1 = NULL;
34
35	/* now, swap the pins */
36	err = renameat2(0, pinpath1, 0, pinpath2, RENAME_EXCHANGE);
37	if (!ASSERT_OK(err, "swap pins"))
38		goto out;
39
40	/* load the object again, this time the re-use should fail */
41	skel1 = test_pinning_devmap__open_and_load();
42	if (!ASSERT_ERR_PTR(skel1, "skel_load3"))
43		goto out;
44
45out:
46	unlink(pinpath1);
47	unlink(pinpath2);
48	test_pinning_devmap__destroy(skel1);
49	test_pinning_devmap__destroy(skel2);
50}