1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2020 Facebook */
3
4#include <linux/bpf.h>
5#include <stdint.h>
6#include <bpf/bpf_helpers.h>
7#include <bpf/bpf_core_read.h>
8
9char _license[] SEC("license") = "GPL";
10
11/* fields of exactly the same size */
12struct test_struct___samesize {
13	void *ptr;
14	unsigned long long val1;
15	unsigned int val2;
16	unsigned short val3;
17	unsigned char val4;
18} __attribute((preserve_access_index));
19
20/* unsigned fields that have to be downsized by libbpf */
21struct test_struct___downsize {
22	void *ptr;
23	unsigned long val1;
24	unsigned long val2;
25	unsigned long val3;
26	unsigned long val4;
27	/* total sz: 40 */
28} __attribute__((preserve_access_index));
29
30/* fields with signed integers of wrong size, should be rejected */
31struct test_struct___signed {
32	void *ptr;
33	long val1;
34	long val2;
35	long val3;
36	long val4;
37} __attribute((preserve_access_index));
38
39/* real layout and sizes according to test's (32-bit) BTF */
40struct test_struct___real {
41	unsigned int ptr; /* can't use `void *`, it is always 8 byte in BPF target */
42	unsigned int val2;
43	unsigned long long val1;
44	unsigned short val3;
45	unsigned char val4;
46	unsigned char _pad;
47	/* total sz: 20 */
48};
49
50struct test_struct___real input = {
51	.ptr = 0x01020304,
52	.val1 = 0x1020304050607080,
53	.val2 = 0x0a0b0c0d,
54	.val3 = 0xfeed,
55	.val4 = 0xb9,
56	._pad = 0xff, /* make sure no accidental zeros are present */
57};
58
59unsigned long long ptr_samesized = 0;
60unsigned long long val1_samesized = 0;
61unsigned long long val2_samesized = 0;
62unsigned long long val3_samesized = 0;
63unsigned long long val4_samesized = 0;
64struct test_struct___real output_samesized = {};
65
66unsigned long long ptr_downsized = 0;
67unsigned long long val1_downsized = 0;
68unsigned long long val2_downsized = 0;
69unsigned long long val3_downsized = 0;
70unsigned long long val4_downsized = 0;
71struct test_struct___real output_downsized = {};
72
73unsigned long long ptr_probed = 0;
74unsigned long long val1_probed = 0;
75unsigned long long val2_probed = 0;
76unsigned long long val3_probed = 0;
77unsigned long long val4_probed = 0;
78
79unsigned long long ptr_signed = 0;
80unsigned long long val1_signed = 0;
81unsigned long long val2_signed = 0;
82unsigned long long val3_signed = 0;
83unsigned long long val4_signed = 0;
84struct test_struct___real output_signed = {};
85
86SEC("raw_tp/sys_exit")
87int handle_samesize(void *ctx)
88{
89	struct test_struct___samesize *in = (void *)&input;
90	struct test_struct___samesize *out = (void *)&output_samesized;
91
92	ptr_samesized = (unsigned long long)in->ptr;
93	val1_samesized = in->val1;
94	val2_samesized = in->val2;
95	val3_samesized = in->val3;
96	val4_samesized = in->val4;
97
98	out->ptr = in->ptr;
99	out->val1 = in->val1;
100	out->val2 = in->val2;
101	out->val3 = in->val3;
102	out->val4 = in->val4;
103
104	return 0;
105}
106
107SEC("raw_tp/sys_exit")
108int handle_downsize(void *ctx)
109{
110	struct test_struct___downsize *in = (void *)&input;
111	struct test_struct___downsize *out = (void *)&output_downsized;
112
113	ptr_downsized = (unsigned long long)in->ptr;
114	val1_downsized = in->val1;
115	val2_downsized = in->val2;
116	val3_downsized = in->val3;
117	val4_downsized = in->val4;
118
119	out->ptr = in->ptr;
120	out->val1 = in->val1;
121	out->val2 = in->val2;
122	out->val3 = in->val3;
123	out->val4 = in->val4;
124
125	return 0;
126}
127
128#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
129#define bpf_core_read_int bpf_core_read
130#else
131#define bpf_core_read_int(dst, sz, src) ({ \
132	/* Prevent "subtraction from stack pointer prohibited" */ \
133	volatile long __off = sizeof(*dst) - (sz); \
134	bpf_core_read((char *)(dst) + __off, sz, src); \
135})
136#endif
137
138SEC("raw_tp/sys_enter")
139int handle_probed(void *ctx)
140{
141	struct test_struct___downsize *in = (void *)&input;
142	__u64 tmp;
143
144	tmp = 0;
145	bpf_core_read_int(&tmp, bpf_core_field_size(in->ptr), &in->ptr);
146	ptr_probed = tmp;
147
148	tmp = 0;
149	bpf_core_read_int(&tmp, bpf_core_field_size(in->val1), &in->val1);
150	val1_probed = tmp;
151
152	tmp = 0;
153	bpf_core_read_int(&tmp, bpf_core_field_size(in->val2), &in->val2);
154	val2_probed = tmp;
155
156	tmp = 0;
157	bpf_core_read_int(&tmp, bpf_core_field_size(in->val3), &in->val3);
158	val3_probed = tmp;
159
160	tmp = 0;
161	bpf_core_read_int(&tmp, bpf_core_field_size(in->val4), &in->val4);
162	val4_probed = tmp;
163
164	return 0;
165}
166
167SEC("raw_tp/sys_enter")
168int handle_signed(void *ctx)
169{
170	struct test_struct___signed *in = (void *)&input;
171	struct test_struct___signed *out = (void *)&output_signed;
172
173	val2_signed = in->val2;
174	val3_signed = in->val3;
175	val4_signed = in->val4;
176
177	out->val2= in->val2;
178	out->val3= in->val3;
179	out->val4= in->val4;
180
181	return 0;
182}
183