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1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2020, Oracle and/or its affiliates. */
3
4#include "btf_ptr.h"
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7#include <bpf/bpf_core_read.h>
8#include "bpf_misc.h"
9
10#include <errno.h>
11
12long ret = 0;
13int num_subtests = 0;
14int ran_subtests = 0;
15bool skip = false;
16
17#define STRSIZE 2048
18#define EXPECTED_STRSIZE 256
19
20#if defined(bpf_target_s390)
21/* NULL points to a readable struct lowcore on s390, so take the last page */
22#define BADPTR ((void *)0xFFFFFFFFFFFFF000ULL)
23#else
24#define BADPTR 0
25#endif
26
27struct {
28 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
29 __uint(max_entries, 1);
30 __type(key, __u32);
31 __type(value, char[STRSIZE]);
32} strdata SEC(".maps");
33
34static int __strncmp(const void *m1, const void *m2, size_t len)
35{
36 const unsigned char *s1 = m1;
37 const unsigned char *s2 = m2;
38 int i, delta = 0;
39
40 for (i = 0; i < len; i++) {
41 delta = s1[i] - s2[i];
42 if (delta || s1[i] == 0 || s2[i] == 0)
43 break;
44 }
45 return delta;
46}
47
48#if __has_builtin(__builtin_btf_type_id)
49#define TEST_BTF(_str, _type, _flags, _expected, ...) \
50 do { \
51 static const char _expectedval[EXPECTED_STRSIZE] = \
52 _expected; \
53 __u64 _hflags = _flags | BTF_F_COMPACT; \
54 static _type _ptrdata = __VA_ARGS__; \
55 static struct btf_ptr _ptr = { }; \
56 int _cmp; \
57 \
58 ++num_subtests; \
59 if (ret < 0) \
60 break; \
61 ++ran_subtests; \
62 _ptr.ptr = &_ptrdata; \
63 _ptr.type_id = bpf_core_type_id_kernel(_type); \
64 if (_ptr.type_id <= 0) { \
65 ret = -EINVAL; \
66 break; \
67 } \
68 ret = bpf_snprintf_btf(_str, STRSIZE, \
69 &_ptr, sizeof(_ptr), _hflags); \
70 if (ret) \
71 break; \
72 _cmp = __strncmp(_str, _expectedval, EXPECTED_STRSIZE); \
73 if (_cmp != 0) { \
74 bpf_printk("(%d) got %s", _cmp, _str); \
75 bpf_printk("(%d) expected %s", _cmp, \
76 _expectedval); \
77 ret = -EBADMSG; \
78 break; \
79 } \
80 } while (0)
81#endif
82
83/* Use where expected data string matches its stringified declaration */
84#define TEST_BTF_C(_str, _type, _flags, ...) \
85 TEST_BTF(_str, _type, _flags, "(" #_type ")" #__VA_ARGS__, \
86 __VA_ARGS__)
87
88/* TRACE_EVENT(netif_receive_skb,
89 * TP_PROTO(struct sk_buff *skb),
90 */
91SEC("tp_btf/netif_receive_skb")
92int BPF_PROG(trace_netif_receive_skb, struct sk_buff *skb)
93{
94 static __u64 flags[] = { 0, BTF_F_COMPACT, BTF_F_ZERO, BTF_F_PTR_RAW,
95 BTF_F_NONAME, BTF_F_COMPACT | BTF_F_ZERO |
96 BTF_F_PTR_RAW | BTF_F_NONAME };
97 static struct btf_ptr p = { };
98 __u32 key = 0;
99 int i, __ret;
100 char *str;
101
102#if __has_builtin(__builtin_btf_type_id)
103 str = bpf_map_lookup_elem(&strdata, &key);
104 if (!str)
105 return 0;
106
107 /* Ensure we can write skb string representation */
108 p.type_id = bpf_core_type_id_kernel(struct sk_buff);
109 p.ptr = skb;
110 for (i = 0; i < ARRAY_SIZE(flags); i++) {
111 ++num_subtests;
112 ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0);
113 if (ret < 0)
114 bpf_printk("returned %d when writing skb", ret);
115 ++ran_subtests;
116 }
117
118 /* Check invalid ptr value */
119 p.ptr = BADPTR;
120 __ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0);
121 if (__ret >= 0) {
122 bpf_printk("printing %llx should generate error, got (%d)",
123 (unsigned long long)BADPTR, __ret);
124 ret = -ERANGE;
125 }
126
127 /* Verify type display for various types. */
128
129 /* simple int */
130 TEST_BTF_C(str, int, 0, 1234);
131 TEST_BTF(str, int, BTF_F_NONAME, "1234", 1234);
132 /* zero value should be printed at toplevel */
133 TEST_BTF(str, int, 0, "(int)0", 0);
134 TEST_BTF(str, int, BTF_F_NONAME, "0", 0);
135 TEST_BTF(str, int, BTF_F_ZERO, "(int)0", 0);
136 TEST_BTF(str, int, BTF_F_NONAME | BTF_F_ZERO, "0", 0);
137 TEST_BTF_C(str, int, 0, -4567);
138 TEST_BTF(str, int, BTF_F_NONAME, "-4567", -4567);
139
140 /* simple char */
141 TEST_BTF_C(str, char, 0, 100);
142 TEST_BTF(str, char, BTF_F_NONAME, "100", 100);
143 /* zero value should be printed at toplevel */
144 TEST_BTF(str, char, 0, "(char)0", 0);
145 TEST_BTF(str, char, BTF_F_NONAME, "0", 0);
146 TEST_BTF(str, char, BTF_F_ZERO, "(char)0", 0);
147 TEST_BTF(str, char, BTF_F_NONAME | BTF_F_ZERO, "0", 0);
148
149 /* simple typedef */
150 TEST_BTF_C(str, uint64_t, 0, 100);
151 TEST_BTF(str, u64, BTF_F_NONAME, "1", 1);
152 /* zero value should be printed at toplevel */
153 TEST_BTF(str, u64, 0, "(u64)0", 0);
154 TEST_BTF(str, u64, BTF_F_NONAME, "0", 0);
155 TEST_BTF(str, u64, BTF_F_ZERO, "(u64)0", 0);
156 TEST_BTF(str, u64, BTF_F_NONAME|BTF_F_ZERO, "0", 0);
157
158 /* typedef struct */
159 TEST_BTF_C(str, atomic_t, 0, {.counter = (int)1,});
160 TEST_BTF(str, atomic_t, BTF_F_NONAME, "{1,}", {.counter = 1,});
161 /* typedef with 0 value should be printed at toplevel */
162 TEST_BTF(str, atomic_t, 0, "(atomic_t){}", {.counter = 0,});
163 TEST_BTF(str, atomic_t, BTF_F_NONAME, "{}", {.counter = 0,});
164 TEST_BTF(str, atomic_t, BTF_F_ZERO, "(atomic_t){.counter = (int)0,}",
165 {.counter = 0,});
166 TEST_BTF(str, atomic_t, BTF_F_NONAME|BTF_F_ZERO,
167 "{0,}", {.counter = 0,});
168
169 /* enum where enum value does (and does not) exist */
170 TEST_BTF_C(str, enum bpf_cmd, 0, BPF_MAP_CREATE);
171 TEST_BTF(str, enum bpf_cmd, 0, "(enum bpf_cmd)BPF_MAP_CREATE", 0);
172 TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME, "BPF_MAP_CREATE",
173 BPF_MAP_CREATE);
174 TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME|BTF_F_ZERO,
175 "BPF_MAP_CREATE", 0);
176
177 TEST_BTF(str, enum bpf_cmd, BTF_F_ZERO, "(enum bpf_cmd)BPF_MAP_CREATE",
178 BPF_MAP_CREATE);
179 TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME|BTF_F_ZERO,
180 "BPF_MAP_CREATE", BPF_MAP_CREATE);
181 TEST_BTF_C(str, enum bpf_cmd, 0, 2000);
182 TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME, "2000", 2000);
183
184 /* simple struct */
185 TEST_BTF_C(str, struct btf_enum, 0,
186 {.name_off = (__u32)3,.val = (__s32)-1,});
187 TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{3,-1,}",
188 { .name_off = 3, .val = -1,});
189 TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{-1,}",
190 { .name_off = 0, .val = -1,});
191 TEST_BTF(str, struct btf_enum, BTF_F_NONAME|BTF_F_ZERO, "{0,-1,}",
192 { .name_off = 0, .val = -1,});
193 /* empty struct should be printed */
194 TEST_BTF(str, struct btf_enum, 0, "(struct btf_enum){}",
195 { .name_off = 0, .val = 0,});
196 TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{}",
197 { .name_off = 0, .val = 0,});
198 TEST_BTF(str, struct btf_enum, BTF_F_ZERO,
199 "(struct btf_enum){.name_off = (__u32)0,.val = (__s32)0,}",
200 { .name_off = 0, .val = 0,});
201
202 /* struct with pointers */
203 TEST_BTF(str, struct list_head, BTF_F_PTR_RAW,
204 "(struct list_head){.next = (struct list_head *)0x0000000000000001,}",
205 { .next = (struct list_head *)1 });
206 /* NULL pointer should not be displayed */
207 TEST_BTF(str, struct list_head, BTF_F_PTR_RAW,
208 "(struct list_head){}",
209 { .next = (struct list_head *)0 });
210
211 /* struct with char array */
212 TEST_BTF(str, struct bpf_prog_info, 0,
213 "(struct bpf_prog_info){.name = (char[])['f','o','o',],}",
214 { .name = "foo",});
215 TEST_BTF(str, struct bpf_prog_info, BTF_F_NONAME,
216 "{['f','o','o',],}",
217 {.name = "foo",});
218 /* leading null char means do not display string */
219 TEST_BTF(str, struct bpf_prog_info, 0,
220 "(struct bpf_prog_info){}",
221 {.name = {'\0', 'f', 'o', 'o'}});
222 /* handle non-printable characters */
223 TEST_BTF(str, struct bpf_prog_info, 0,
224 "(struct bpf_prog_info){.name = (char[])[1,2,3,],}",
225 { .name = {1, 2, 3, 0}});
226
227 /* struct with non-char array */
228 TEST_BTF(str, struct __sk_buff, 0,
229 "(struct __sk_buff){.cb = (__u32[])[1,2,3,4,5,],}",
230 { .cb = {1, 2, 3, 4, 5,},});
231 TEST_BTF(str, struct __sk_buff, BTF_F_NONAME,
232 "{[1,2,3,4,5,],}",
233 { .cb = { 1, 2, 3, 4, 5},});
234 /* For non-char, arrays, show non-zero values only */
235 TEST_BTF(str, struct __sk_buff, 0,
236 "(struct __sk_buff){.cb = (__u32[])[1,],}",
237 { .cb = { 0, 0, 1, 0, 0},});
238
239 /* struct with bitfields */
240 TEST_BTF_C(str, struct bpf_insn, 0,
241 {.code = (__u8)1,.dst_reg = (__u8)0x2,.src_reg = (__u8)0x3,.off = (__s16)4,.imm = (__s32)5,});
242 TEST_BTF(str, struct bpf_insn, BTF_F_NONAME, "{1,0x2,0x3,4,5,}",
243 {.code = 1, .dst_reg = 0x2, .src_reg = 0x3, .off = 4,
244 .imm = 5,});
245#else
246 skip = true;
247#endif
248
249 return 0;
250}
251
252char _license[] SEC("license") = "GPL";