xref: /linux/tools/testing/selftests/bpf/prog_tests/modify_return.c (revision 7a0e692a0381254b2f77c54dec100cd3325a6fdf)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 /*
4  * Copyright 2020 Google LLC.
5  */
6 
7 #include <test_progs.h>
8 #include <unistd.h>
9 #include "modify_return.skel.h"
10 
11 #define LOWER(x) ((x) & 0xffff)
12 #define UPPER(x) ((x) >> 16)
13 
14 
15 static void run_test(__u32 input_retval, __u16 want_side_effect, __s16 want_ret)
16 {
17 	struct modify_return *skel = NULL;
18 	int err, prog_fd;
19 	__u16 side_effect;
20 	__s16 ret;
21 	LIBBPF_OPTS(bpf_test_run_opts, topts);
22 
23 	skel = modify_return__open_and_load();
24 	if (!ASSERT_OK_PTR(skel, "skel_load"))
25 		goto cleanup;
26 
27 	skel->bss->input_retval = input_retval;
28 	skel->bss->test_pid = getpid();
29 
30 	err = modify_return__attach(skel);
31 	if (!ASSERT_OK(err, "modify_return__attach failed"))
32 		goto cleanup;
33 
34 	prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
35 	err = bpf_prog_test_run_opts(prog_fd, &topts);
36 	ASSERT_OK(err, "test_run");
37 
38 	side_effect = UPPER(topts.retval);
39 	ret = LOWER(topts.retval);
40 
41 	ASSERT_EQ(ret, want_ret, "test_run ret");
42 	ASSERT_EQ(side_effect, want_side_effect, "modify_return side_effect");
43 	ASSERT_EQ(skel->bss->fentry_result, 1, "modify_return fentry_result");
44 	ASSERT_EQ(skel->bss->fexit_result, 1, "modify_return fexit_result");
45 	ASSERT_EQ(skel->bss->fmod_ret_result, 1, "modify_return fmod_ret_result");
46 
47 	ASSERT_EQ(skel->bss->fentry_result2, 1, "modify_return fentry_result2");
48 	ASSERT_EQ(skel->bss->fexit_result2, 1, "modify_return fexit_result2");
49 	ASSERT_EQ(skel->bss->fmod_ret_result2, 1, "modify_return fmod_ret_result2");
50 
51 cleanup:
52 	modify_return__destroy(skel);
53 }
54 
55 void test_modify_return(void)
56 {
57 	run_test(0 /* input_retval */,
58 		 2 /* want_side_effect */,
59 		 33 /* want_ret */);
60 	run_test(-EINVAL /* input_retval */,
61 		 0 /* want_side_effect */,
62 		 -EINVAL * 2 /* want_ret */);
63 }
64