Add selftests validating link pinning/unpinning and associated BPF link
(attachment) lifetime.
Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
---
.../selftests/bpf/prog_tests/link_pinning.c | 105 ++++++++++++++++++
.../selftests/bpf/progs/test_link_pinning.c | 25 +++++
2 files changed, 130 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/link_pinning.c
create mode 100644 tools/testing/selftests/bpf/progs/test_link_pinning.c
diff --git a/tools/testing/selftests/bpf/prog_tests/link_pinning.c b/tools/testing/selftests/bpf/prog_tests/link_pinning.c
new file mode 100644
index 000000000000..a743288cf384
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/link_pinning.c
@@ -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);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_link_pinning.c b/tools/testing/selftests/bpf/progs/test_link_pinning.c
new file mode 100644
index 000000000000..bbf2a5264dc0
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_link_pinning.c
@@ -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";
--
2.17.1
