Commit ba7499bc authored by Alan Maguire's avatar Alan Maguire Committed by Andrii Nakryiko
Browse files

selftests/bpf: Add tests for u[ret]probe attach by name 



add tests that verify attaching by name for

1. local functions in a program
2. library functions in a shared object

...succeed for uprobe and uretprobes using new "func_name"
option for bpf_program__attach_uprobe_opts().  Also verify
auto-attach works where uprobe, path to binary and function
name are specified, but fails with -EOPNOTSUPP with a SEC
name that does not specify binary path/function.

Signed-off-by: default avatarAlan Maguire <alan.maguire@oracle.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1648654000-21758-5-git-send-email-alan.maguire@oracle.com
parent 39f8dc43

tools/testing/selftests/bpf/prog_tests/attach_probe.c

+70 −15
Original line number Diff line number Diff line
@@ -11,15 +11,22 @@ static void trigger_func(void) 
	asm volatile ("");

}



/* attach point for byname uprobe */

static void trigger_func2(void)

{

	asm volatile ("");

}



void test_attach_probe(void)

{

	DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);

	int duration = 0;

	struct bpf_link *kprobe_link, *kretprobe_link;

	struct bpf_link *uprobe_link, *uretprobe_link;

	struct test_attach_probe* skel;

	ssize_t uprobe_offset, ref_ctr_offset;

	struct bpf_link *uprobe_err_link;

	bool legacy;

	char *mem;



	/* Check if new-style kprobe/uprobe API is supported.

	 * Kernels that support new FD-based kprobe and uprobe BPF attachment
@@ -43,9 +50,9 @@ void test_attach_probe(void) 
		return;



	skel = test_attach_probe__open_and_load();

	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))

	if (!ASSERT_OK_PTR(skel, "skel_open"))

		return;

	if (CHECK(!skel->bss, "check_bss", ".bss wasn't mmap()-ed\n"))

	if (!ASSERT_OK_PTR(skel->bss, "check_bss"))

		goto cleanup;



	kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe,
@@ -90,25 +97,73 @@ void test_attach_probe(void) 
		goto cleanup;

	skel->links.handle_uretprobe = uretprobe_link;



	/* trigger & validate kprobe && kretprobe */

	usleep(1);

	/* verify auto-attach fails for old-style uprobe definition */

	uprobe_err_link = bpf_program__attach(skel->progs.handle_uprobe_byname);

	if (!ASSERT_EQ(libbpf_get_error(uprobe_err_link), -EOPNOTSUPP,

		       "auto-attach should fail for old-style name"))

		goto cleanup;



	uprobe_opts.func_name = "trigger_func2";

	uprobe_opts.retprobe = false;

	uprobe_opts.ref_ctr_offset = 0;

	skel->links.handle_uprobe_byname =

			bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname,

							0 /* this pid */,

							"/proc/self/exe",

							0, &uprobe_opts);

	if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname, "attach_uprobe_byname"))

		goto cleanup;



	/* verify auto-attach works */

	skel->links.handle_uretprobe_byname =

			bpf_program__attach(skel->progs.handle_uretprobe_byname);

	if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname, "attach_uretprobe_byname"))

		goto cleanup;



	if (CHECK(skel->bss->kprobe_res != 1, "check_kprobe_res",

		  "wrong kprobe res: %d\n", skel->bss->kprobe_res))

	/* test attach by name for a library function, using the library

	 * as the binary argument. libc.so.6 will be resolved via dlopen()/dlinfo().

	 */

	uprobe_opts.func_name = "malloc";

	uprobe_opts.retprobe = false;

	skel->links.handle_uprobe_byname2 =

			bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_byname2,

							0 /* this pid */,

							"libc.so.6",

							0, &uprobe_opts);

	if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname2, "attach_uprobe_byname2"))

		goto cleanup;

	if (CHECK(skel->bss->kretprobe_res != 2, "check_kretprobe_res",

		  "wrong kretprobe res: %d\n", skel->bss->kretprobe_res))



	uprobe_opts.func_name = "free";

	uprobe_opts.retprobe = true;

	skel->links.handle_uretprobe_byname2 =

			bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe_byname2,

							-1 /* any pid */,

							"libc.so.6",

							0, &uprobe_opts);

	if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname2, "attach_uretprobe_byname2"))

		goto cleanup;



	/* trigger & validate kprobe && kretprobe */

	usleep(1);



	/* trigger & validate shared library u[ret]probes attached by name */

	mem = malloc(1);

	free(mem);



	/* trigger & validate uprobe & uretprobe */

	trigger_func();



	if (CHECK(skel->bss->uprobe_res != 3, "check_uprobe_res",

		  "wrong uprobe res: %d\n", skel->bss->uprobe_res))

		goto cleanup;

	if (CHECK(skel->bss->uretprobe_res != 4, "check_uretprobe_res",

		  "wrong uretprobe res: %d\n", skel->bss->uretprobe_res))

		goto cleanup;

	/* trigger & validate uprobe attached by name */

	trigger_func2();



	ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res");

	ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res");

	ASSERT_EQ(skel->bss->uprobe_res, 3, "check_uprobe_res");

	ASSERT_EQ(skel->bss->uretprobe_res, 4, "check_uretprobe_res");

	ASSERT_EQ(skel->bss->uprobe_byname_res, 5, "check_uprobe_byname_res");

	ASSERT_EQ(skel->bss->uretprobe_byname_res, 6, "check_uretprobe_byname_res");

	ASSERT_EQ(skel->bss->uprobe_byname2_res, 7, "check_uprobe_byname2_res");

	ASSERT_EQ(skel->bss->uretprobe_byname2_res, 8, "check_uretprobe_byname2_res");



cleanup:

	test_attach_probe__destroy(skel);

tools/testing/selftests/bpf/progs/test_attach_probe.c

+39 −2
Original line number Diff line number Diff line
@@ -10,6 +10,10 @@ int kprobe_res = 0; 
int kretprobe_res = 0;

int uprobe_res = 0;

int uretprobe_res = 0;

int uprobe_byname_res = 0;

int uretprobe_byname_res = 0;

int uprobe_byname2_res = 0;

int uretprobe_byname2_res = 0;



SEC("kprobe/sys_nanosleep")

int handle_kprobe(struct pt_regs *ctx)
@@ -25,18 +29,51 @@ int BPF_KRETPROBE(handle_kretprobe) 
	return 0;

}



SEC("uprobe/trigger_func")

SEC("uprobe")

int handle_uprobe(struct pt_regs *ctx)

{

	uprobe_res = 3;

	return 0;

}



SEC("uretprobe/trigger_func")

SEC("uretprobe")

int handle_uretprobe(struct pt_regs *ctx)

{

	uretprobe_res = 4;

	return 0;

}



SEC("uprobe")

int handle_uprobe_byname(struct pt_regs *ctx)

{

	uprobe_byname_res = 5;

	return 0;

}



/* use auto-attach format for section definition. */

SEC("uretprobe//proc/self/exe:trigger_func2")

int handle_uretprobe_byname(struct pt_regs *ctx)

{

	uretprobe_byname_res = 6;

	return 0;

}



SEC("uprobe")

int handle_uprobe_byname2(struct pt_regs *ctx)

{

	unsigned int size = PT_REGS_PARM1(ctx);



	/* verify malloc size */

	if (size == 1)

		uprobe_byname2_res = 7;

	return 0;

}



SEC("uretprobe")

int handle_uretprobe_byname2(struct pt_regs *ctx)

{

	uretprobe_byname2_res = 8;

	return 0;

}



char _license[] SEC("license") = "GPL";