1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/bpf.h>
  3#include <bpf/bpf_helpers.h>
  4#include <bpf/bpf_tracing.h>
  5#include <errno.h>
  6
  7char _license[] SEC("license") = "GPL";
  8
  9__u64 test1_result = 0;
 10SEC("fentry/bpf_fentry_test1")
 11int BPF_PROG(test1)
 12{
 13	__u64 cnt = bpf_get_func_arg_cnt(ctx);
 14	__u64 a = 0, z = 0, ret = 0;
 15	__s64 err;
 16
 17	test1_result = cnt == 1;
 18
 19	/* valid arguments */
 20	err = bpf_get_func_arg(ctx, 0, &a);
 21
 22	/* We need to cast access to traced function argument values with
 23	 * proper type cast, because trampoline uses type specific instruction
 24	 * to save it, like for 'int a' with 32-bit mov like:
 25	 *
 26	 *   mov %edi,-0x8(%rbp)
 27	 *
 28	 * so the upper 4 bytes are not zeroed.
 29	 */
 30	test1_result &= err == 0 && ((int) a == 1);
 31
 32	/* not valid argument */
 33	err = bpf_get_func_arg(ctx, 1, &z);
 34	test1_result &= err == -EINVAL;
 35
 36	/* return value fails in fentry */
 37	err = bpf_get_func_ret(ctx, &ret);
 38	test1_result &= err == -EOPNOTSUPP;
 39	return 0;
 40}
 41
 42__u64 test2_result = 0;
 43SEC("fexit/bpf_fentry_test2")
 44int BPF_PROG(test2)
 45{
 46	__u64 cnt = bpf_get_func_arg_cnt(ctx);
 47	__u64 a = 0, b = 0, z = 0, ret = 0;
 48	__s64 err;
 49
 50	test2_result = cnt == 2;
 51
 52	/* valid arguments */
 53	err = bpf_get_func_arg(ctx, 0, &a);
 54	test2_result &= err == 0 && (int) a == 2;
 55
 56	err = bpf_get_func_arg(ctx, 1, &b);
 57	test2_result &= err == 0 && b == 3;
 58
 59	/* not valid argument */
 60	err = bpf_get_func_arg(ctx, 2, &z);
 61	test2_result &= err == -EINVAL;
 62
 63	/* return value */
 64	err = bpf_get_func_ret(ctx, &ret);
 65	test2_result &= err == 0 && ret == 5;
 66	return 0;
 67}
 68
 69__u64 test3_result = 0;
 70SEC("fmod_ret/bpf_modify_return_test")
 71int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
 72{
 73	__u64 cnt = bpf_get_func_arg_cnt(ctx);
 74	__u64 a = 0, b = 0, z = 0, ret = 0;
 75	__s64 err;
 76
 77	test3_result = cnt == 2;
 78
 79	/* valid arguments */
 80	err = bpf_get_func_arg(ctx, 0, &a);
 81	test3_result &= err == 0 && ((int) a == 1);
 82
 83	err = bpf_get_func_arg(ctx, 1, &b);
 84	test3_result &= err == 0 && ((int *) b == _b);
 85
 86	/* not valid argument */
 87	err = bpf_get_func_arg(ctx, 2, &z);
 88	test3_result &= err == -EINVAL;
 89
 90	/* return value */
 91	err = bpf_get_func_ret(ctx, &ret);
 92	test3_result &= err == 0 && ret == 0;
 93
 94	/* change return value, it's checked in fexit_test program */
 95	return 1234;
 96}
 97
 98__u64 test4_result = 0;
 99SEC("fexit/bpf_modify_return_test")
100int BPF_PROG(fexit_test, int _a, int *_b, int _ret)
101{
102	__u64 cnt = bpf_get_func_arg_cnt(ctx);
103	__u64 a = 0, b = 0, z = 0, ret = 0;
104	__s64 err;
105
106	test4_result = cnt == 2;
107
108	/* valid arguments */
109	err = bpf_get_func_arg(ctx, 0, &a);
110	test4_result &= err == 0 && ((int) a == 1);
111
112	err = bpf_get_func_arg(ctx, 1, &b);
113	test4_result &= err == 0 && ((int *) b == _b);
114
115	/* not valid argument */
116	err = bpf_get_func_arg(ctx, 2, &z);
117	test4_result &= err == -EINVAL;
118
119	/* return value */
120	err = bpf_get_func_ret(ctx, &ret);
121	test4_result &= err == 0 && ret == 1234;
122	return 0;
123}