linux-zen-server/tools/testing/selftests/bpf/prog_tests/custom_sec_handlers.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Facebook */

#include <test_progs.h>
#include "test_custom_sec_handlers.skel.h"

#define COOKIE_ABC1 1
#define COOKIE_ABC2 2
#define COOKIE_CUSTOM 3
#define COOKIE_FALLBACK 4
#define COOKIE_KPROBE 5

static int custom_setup_prog(struct bpf_program *prog, long cookie)
{
	if (cookie == COOKIE_ABC1)
		bpf_program__set_autoload(prog, false);

	return 0;
}

static int custom_prepare_load_prog(struct bpf_program *prog,
				    struct bpf_prog_load_opts *opts, long cookie)
{
	if (cookie == COOKIE_FALLBACK)
		opts->prog_flags |= BPF_F_SLEEPABLE;
	else if (cookie == COOKIE_ABC1)
		ASSERT_FALSE(true, "unexpected preload for abc");

	return 0;
}

static int custom_attach_prog(const struct bpf_program *prog, long cookie,
			      struct bpf_link **link)
{
	switch (cookie) {
	case COOKIE_ABC2:
		*link = bpf_program__attach_raw_tracepoint(prog, "sys_enter");
		return libbpf_get_error(*link);
	case COOKIE_CUSTOM:
		*link = bpf_program__attach_tracepoint(prog, "syscalls", "sys_enter_nanosleep");
		return libbpf_get_error(*link);
	case COOKIE_KPROBE:
	case COOKIE_FALLBACK:
		/* no auto-attach for SEC("xyz") and SEC("kprobe") */
		*link = NULL;
		return 0;
	default:
		ASSERT_FALSE(true, "unexpected cookie");
		return -EINVAL;
	}
}

static int abc1_id;
static int abc2_id;
static int custom_id;
static int fallback_id;
static int kprobe_id;

__attribute__((constructor))
static void register_sec_handlers(void)
{
	LIBBPF_OPTS(libbpf_prog_handler_opts, abc1_opts,
		.cookie = COOKIE_ABC1,
		.prog_setup_fn = custom_setup_prog,
		.prog_prepare_load_fn = custom_prepare_load_prog,
		.prog_attach_fn = NULL,
	);
	LIBBPF_OPTS(libbpf_prog_handler_opts, abc2_opts,
		.cookie = COOKIE_ABC2,
		.prog_setup_fn = custom_setup_prog,
		.prog_prepare_load_fn = custom_prepare_load_prog,
		.prog_attach_fn = custom_attach_prog,
	);
	LIBBPF_OPTS(libbpf_prog_handler_opts, custom_opts,
		.cookie = COOKIE_CUSTOM,
		.prog_setup_fn = NULL,
		.prog_prepare_load_fn = NULL,
		.prog_attach_fn = custom_attach_prog,
	);

	abc1_id = libbpf_register_prog_handler("abc", BPF_PROG_TYPE_RAW_TRACEPOINT, 0, &abc1_opts);
	abc2_id = libbpf_register_prog_handler("abc/", BPF_PROG_TYPE_RAW_TRACEPOINT, 0, &abc2_opts);
	custom_id = libbpf_register_prog_handler("custom+", BPF_PROG_TYPE_TRACEPOINT, 0, &custom_opts);
}

__attribute__((destructor))
static void unregister_sec_handlers(void)
{
	libbpf_unregister_prog_handler(abc1_id);
	libbpf_unregister_prog_handler(abc2_id);
	libbpf_unregister_prog_handler(custom_id);
}

void test_custom_sec_handlers(void)
{
	LIBBPF_OPTS(libbpf_prog_handler_opts, opts,
		.prog_setup_fn = custom_setup_prog,
		.prog_prepare_load_fn = custom_prepare_load_prog,
		.prog_attach_fn = custom_attach_prog,
	);
	struct test_custom_sec_handlers* skel;
	int err;

	ASSERT_GT(abc1_id, 0, "abc1_id");
	ASSERT_GT(abc2_id, 0, "abc2_id");
	ASSERT_GT(custom_id, 0, "custom_id");

	/* override libbpf's handle of SEC("kprobe/...") but also allow pure
	 * SEC("kprobe") due to "kprobe+" specifier. Register it as
	 * TRACEPOINT, just for fun.
	 */
	opts.cookie = COOKIE_KPROBE;
	kprobe_id = libbpf_register_prog_handler("kprobe+", BPF_PROG_TYPE_TRACEPOINT, 0, &opts);
	/* fallback treats everything as BPF_PROG_TYPE_SYSCALL program to test
	 * setting custom BPF_F_SLEEPABLE bit in preload handler
	 */
	opts.cookie = COOKIE_FALLBACK;
	fallback_id = libbpf_register_prog_handler(NULL, BPF_PROG_TYPE_SYSCALL, 0, &opts);

	if (!ASSERT_GT(fallback_id, 0, "fallback_id") /* || !ASSERT_GT(kprobe_id, 0, "kprobe_id")*/) {
		if (fallback_id > 0)
			libbpf_unregister_prog_handler(fallback_id);
		if (kprobe_id > 0)
			libbpf_unregister_prog_handler(kprobe_id);
		return;
	}

	/* open skeleton and validate assumptions */
	skel = test_custom_sec_handlers__open();
	if (!ASSERT_OK_PTR(skel, "skel_open"))
		goto cleanup;

	ASSERT_EQ(bpf_program__type(skel->progs.abc1), BPF_PROG_TYPE_RAW_TRACEPOINT, "abc1_type");
	ASSERT_FALSE(bpf_program__autoload(skel->progs.abc1), "abc1_autoload");

	ASSERT_EQ(bpf_program__type(skel->progs.abc2), BPF_PROG_TYPE_RAW_TRACEPOINT, "abc2_type");
	ASSERT_EQ(bpf_program__type(skel->progs.custom1), BPF_PROG_TYPE_TRACEPOINT, "custom1_type");
	ASSERT_EQ(bpf_program__type(skel->progs.custom2), BPF_PROG_TYPE_TRACEPOINT, "custom2_type");
	ASSERT_EQ(bpf_program__type(skel->progs.kprobe1), BPF_PROG_TYPE_TRACEPOINT, "kprobe1_type");
	ASSERT_EQ(bpf_program__type(skel->progs.xyz), BPF_PROG_TYPE_SYSCALL, "xyz_type");

	skel->rodata->my_pid = getpid();

	/* now attempt to load everything */
	err = test_custom_sec_handlers__load(skel);
	if (!ASSERT_OK(err, "skel_load"))
		goto cleanup;

	/* now try to auto-attach everything */
	err = test_custom_sec_handlers__attach(skel);
	if (!ASSERT_OK(err, "skel_attach"))
		goto cleanup;

	skel->links.xyz = bpf_program__attach(skel->progs.kprobe1);
	ASSERT_EQ(errno, EOPNOTSUPP, "xyz_attach_err");
	ASSERT_ERR_PTR(skel->links.xyz, "xyz_attach");

	/* trigger programs */
	usleep(1);

	/* SEC("abc") is set to not auto-loaded */
	ASSERT_FALSE(skel->bss->abc1_called, "abc1_called");
	ASSERT_TRUE(skel->bss->abc2_called, "abc2_called");
	ASSERT_TRUE(skel->bss->custom1_called, "custom1_called");
	ASSERT_TRUE(skel->bss->custom2_called, "custom2_called");
	/* SEC("kprobe") shouldn't be auto-attached */
	ASSERT_FALSE(skel->bss->kprobe1_called, "kprobe1_called");
	/* SEC("xyz") shouldn't be auto-attached */
	ASSERT_FALSE(skel->bss->xyz_called, "xyz_called");

cleanup:
	test_custom_sec_handlers__destroy(skel);

	ASSERT_OK(libbpf_unregister_prog_handler(fallback_id), "unregister_fallback");
	ASSERT_OK(libbpf_unregister_prog_handler(kprobe_id), "unregister_kprobe");
}