selftests/bpf: Add link pinning selftests

Add selftests validating link pinning/unpinning and associated BPF link
(attachment) lifetime.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200303043159.323675-4-andriin@fb.com
This commit is contained in:
Andrii Nakryiko 2020-03-02 20:31:59 -08:00 committed by Alexei Starovoitov
parent c016b68edc
commit 6489b8e1e3
2 changed files with 130 additions and 0 deletions

View File

@ -0,0 +1,105 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <test_progs.h>
#include <sys/stat.h>
#include "test_link_pinning.skel.h"
static int duration = 0;
void test_link_pinning_subtest(struct bpf_program *prog,
struct test_link_pinning__bss *bss)
{
const char *link_pin_path = "/sys/fs/bpf/pinned_link_test";
struct stat statbuf = {};
struct bpf_link *link;
int err, i;
link = bpf_program__attach(prog);
if (CHECK(IS_ERR(link), "link_attach", "err: %ld\n", PTR_ERR(link)))
goto cleanup;
bss->in = 1;
usleep(1);
CHECK(bss->out != 1, "res_check1", "exp %d, got %d\n", 1, bss->out);
/* pin link */
err = bpf_link__pin(link, link_pin_path);
if (CHECK(err, "link_pin", "err: %d\n", err))
goto cleanup;
CHECK(strcmp(link_pin_path, bpf_link__pin_path(link)), "pin_path1",
"exp %s, got %s\n", link_pin_path, bpf_link__pin_path(link));
/* check that link was pinned */
err = stat(link_pin_path, &statbuf);
if (CHECK(err, "stat_link", "err %d errno %d\n", err, errno))
goto cleanup;
bss->in = 2;
usleep(1);
CHECK(bss->out != 2, "res_check2", "exp %d, got %d\n", 2, bss->out);
/* destroy link, pinned link should keep program attached */
bpf_link__destroy(link);
link = NULL;
bss->in = 3;
usleep(1);
CHECK(bss->out != 3, "res_check3", "exp %d, got %d\n", 3, bss->out);
/* re-open link from BPFFS */
link = bpf_link__open(link_pin_path);
if (CHECK(IS_ERR(link), "link_open", "err: %ld\n", PTR_ERR(link)))
goto cleanup;
CHECK(strcmp(link_pin_path, bpf_link__pin_path(link)), "pin_path2",
"exp %s, got %s\n", link_pin_path, bpf_link__pin_path(link));
/* unpin link from BPFFS, program still attached */
err = bpf_link__unpin(link);
if (CHECK(err, "link_unpin", "err: %d\n", err))
goto cleanup;
/* still active, as we have FD open now */
bss->in = 4;
usleep(1);
CHECK(bss->out != 4, "res_check4", "exp %d, got %d\n", 4, bss->out);
bpf_link__destroy(link);
link = NULL;
/* Validate it's finally detached.
* Actual detachment might get delayed a bit, so there is no reliable
* way to validate it immediately here, let's count up for long enough
* and see if eventually output stops being updated
*/
for (i = 5; i < 10000; i++) {
bss->in = i;
usleep(1);
if (bss->out == i - 1)
break;
}
CHECK(i == 10000, "link_attached", "got to iteration #%d\n", i);
cleanup:
if (!IS_ERR(link))
bpf_link__destroy(link);
}
void test_link_pinning(void)
{
struct test_link_pinning* skel;
skel = test_link_pinning__open_and_load();
if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
return;
if (test__start_subtest("pin_raw_tp"))
test_link_pinning_subtest(skel->progs.raw_tp_prog, skel->bss);
if (test__start_subtest("pin_tp_btf"))
test_link_pinning_subtest(skel->progs.tp_btf_prog, skel->bss);
test_link_pinning__destroy(skel);
}

View File

@ -0,0 +1,25 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <stdbool.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
int in = 0;
int out = 0;
SEC("raw_tp/sys_enter")
int raw_tp_prog(const void *ctx)
{
out = in;
return 0;
}
SEC("tp_btf/sys_enter")
int tp_btf_prog(const void *ctx)
{
out = in;
return 0;
}
char _license[] SEC("license") = "GPL";