selftests/bpf: Add set_attach_target() API selftest for module target

Add test for bpf_program__set_attach_target() API, validating it can find
kernel module fentry target.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201211215825.3646154-3-andrii@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/module_attach.c b/tools/testing/selftests/bpf/prog_tests/module_attach.c
index 4b65e99..50796b6 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/module_attach.c
+++ b/tools/testing/selftests/bpf/prog_tests/module_attach.c
@@ -28,10 +28,18 @@ void test_module_attach(void)
        struct test_module_attach__bss *bss;
        int err;
 
-       skel = test_module_attach__open_and_load();
+       skel = test_module_attach__open();
        if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
                return;
 
+       err = bpf_program__set_attach_target(skel->progs.handle_fentry_manual,
+                                            0, "bpf_testmod_test_read");
+       ASSERT_OK(err, "set_attach_target");
+
+       err = test_module_attach__load(skel);
+       if (CHECK(err, "skel_load", "failed to load skeleton\n"))
+               return;
+
        bss = skel->bss;
 
        err = test_module_attach__attach(skel);
@@ -44,6 +52,7 @@ void test_module_attach(void)
        ASSERT_EQ(bss->raw_tp_read_sz, READ_SZ, "raw_tp");
        ASSERT_EQ(bss->tp_btf_read_sz, READ_SZ, "tp_btf");
        ASSERT_EQ(bss->fentry_read_sz, READ_SZ, "fentry");
+       ASSERT_EQ(bss->fentry_manual_read_sz, READ_SZ, "fentry_manual");
        ASSERT_EQ(bss->fexit_read_sz, READ_SZ, "fexit");
        ASSERT_EQ(bss->fexit_ret, -EIO, "fexit_tet");
        ASSERT_EQ(bss->fmod_ret_read_sz, READ_SZ, "fmod_ret");

diff --git a/tools/testing/selftests/bpf/progs/test_module_attach.c b/tools/testing/selftests/bpf/progs/test_module_attach.c
index b563563..efd1e28 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_module_attach.c
+++ b/tools/testing/selftests/bpf/progs/test_module_attach.c
@@ -38,6 +38,17 @@ int BPF_PROG(handle_fentry,
        return 0;
 }
 
+__u32 fentry_manual_read_sz = 0;
+
+SEC("fentry/placeholder")
+int BPF_PROG(handle_fentry_manual,
+            struct file *file, struct kobject *kobj,
+            struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
+{
+       fentry_manual_read_sz = len;
+       return 0;
+}
+
 __u32 fexit_read_sz = 0;
 int fexit_ret = 0;