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
9 #include <errno.h>
10
11 long ret = 0;
12 int num_subtests = 0;
13 int ran_subtests = 0;
14 bool skip = false;
15
16 #define STRSIZE 2048
17 #define EXPECTED_STRSIZE 256
18
19 #if defined(bpf_target_s390)
20 /* NULL points to a readable struct lowcore on s390, so take the last page */
21 #define BADPTR ((void *)0xFFFFFFFFFFFFF000ULL)
22 #else
23 #define BADPTR 0
24 #endif
25
26 #ifndef ARRAY_SIZE
27 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
28 #endif
29
30 struct {
31 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
32 __uint(max_entries, 1);
33 __type(key, __u32);
34 __type(value, char[STRSIZE]);
35 } strdata SEC(".maps");
36
__strncmp(const void * m1,const void * m2,size_t len)37 static int __strncmp(const void *m1, const void *m2, size_t len)
38 {
39 const unsigned char *s1 = m1;
40 const unsigned char *s2 = m2;
41 int i, delta = 0;
42
43 for (i = 0; i < len; i++) {
44 delta = s1[i] - s2[i];
45 if (delta || s1[i] == 0 || s2[i] == 0)
46 break;
47 }
48 return delta;
49 }
50
51 #if __has_builtin(__builtin_btf_type_id)
52 #define TEST_BTF(_str, _type, _flags, _expected, ...) \
53 do { \
54 static const char _expectedval[EXPECTED_STRSIZE] = \
55 _expected; \
56 __u64 _hflags = _flags | BTF_F_COMPACT; \
57 static _type _ptrdata = __VA_ARGS__; \
58 static struct btf_ptr _ptr = { }; \
59 int _cmp; \
60 \
61 ++num_subtests; \
62 if (ret < 0) \
63 break; \
64 ++ran_subtests; \
65 _ptr.ptr = &_ptrdata; \
66 _ptr.type_id = bpf_core_type_id_kernel(_type); \
67 if (_ptr.type_id <= 0) { \
68 ret = -EINVAL; \
69 break; \
70 } \
71 ret = bpf_snprintf_btf(_str, STRSIZE, \
72 &_ptr, sizeof(_ptr), _hflags); \
73 if (ret) \
74 break; \
75 _cmp = __strncmp(_str, _expectedval, EXPECTED_STRSIZE); \
76 if (_cmp != 0) { \
77 bpf_printk("(%d) got %s", _cmp, _str); \
78 bpf_printk("(%d) expected %s", _cmp, \
79 _expectedval); \
80 ret = -EBADMSG; \
81 break; \
82 } \
83 } while (0)
84 #endif
85
86 /* Use where expected data string matches its stringified declaration */
87 #define TEST_BTF_C(_str, _type, _flags, ...) \
88 TEST_BTF(_str, _type, _flags, "(" #_type ")" #__VA_ARGS__, \
89 __VA_ARGS__)
90
91 /* TRACE_EVENT(netif_receive_skb,
92 * TP_PROTO(struct sk_buff *skb),
93 */
94 SEC("tp_btf/netif_receive_skb")
BPF_PROG(trace_netif_receive_skb,struct sk_buff * skb)95 int BPF_PROG(trace_netif_receive_skb, struct sk_buff *skb)
96 {
97 static __u64 flags[] = { 0, BTF_F_COMPACT, BTF_F_ZERO, BTF_F_PTR_RAW,
98 BTF_F_NONAME, BTF_F_COMPACT | BTF_F_ZERO |
99 BTF_F_PTR_RAW | BTF_F_NONAME };
100 static struct btf_ptr p = { };
101 __u32 key = 0;
102 int i, __ret;
103 char *str;
104
105 #if __has_builtin(__builtin_btf_type_id)
106 str = bpf_map_lookup_elem(&strdata, &key);
107 if (!str)
108 return 0;
109
110 /* Ensure we can write skb string representation */
111 p.type_id = bpf_core_type_id_kernel(struct sk_buff);
112 p.ptr = skb;
113 for (i = 0; i < ARRAY_SIZE(flags); i++) {
114 ++num_subtests;
115 ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0);
116 if (ret < 0)
117 bpf_printk("returned %d when writing skb", ret);
118 ++ran_subtests;
119 }
120
121 /* Check invalid ptr value */
122 p.ptr = BADPTR;
123 __ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0);
124 if (__ret >= 0) {
125 bpf_printk("printing %llx should generate error, got (%d)",
126 (unsigned long long)BADPTR, __ret);
127 ret = -ERANGE;
128 }
129
130 /* Verify type display for various types. */
131
132 /* simple int */
133 TEST_BTF_C(str, int, 0, 1234);
134 TEST_BTF(str, int, BTF_F_NONAME, "1234", 1234);
135 /* zero value should be printed at toplevel */
136 TEST_BTF(str, int, 0, "(int)0", 0);
137 TEST_BTF(str, int, BTF_F_NONAME, "0", 0);
138 TEST_BTF(str, int, BTF_F_ZERO, "(int)0", 0);
139 TEST_BTF(str, int, BTF_F_NONAME | BTF_F_ZERO, "0", 0);
140 TEST_BTF_C(str, int, 0, -4567);
141 TEST_BTF(str, int, BTF_F_NONAME, "-4567", -4567);
142
143 /* simple char */
144 TEST_BTF_C(str, char, 0, 100);
145 TEST_BTF(str, char, BTF_F_NONAME, "100", 100);
146 /* zero value should be printed at toplevel */
147 TEST_BTF(str, char, 0, "(char)0", 0);
148 TEST_BTF(str, char, BTF_F_NONAME, "0", 0);
149 TEST_BTF(str, char, BTF_F_ZERO, "(char)0", 0);
150 TEST_BTF(str, char, BTF_F_NONAME | BTF_F_ZERO, "0", 0);
151
152 /* simple typedef */
153 TEST_BTF_C(str, uint64_t, 0, 100);
154 TEST_BTF(str, u64, BTF_F_NONAME, "1", 1);
155 /* zero value should be printed at toplevel */
156 TEST_BTF(str, u64, 0, "(u64)0", 0);
157 TEST_BTF(str, u64, BTF_F_NONAME, "0", 0);
158 TEST_BTF(str, u64, BTF_F_ZERO, "(u64)0", 0);
159 TEST_BTF(str, u64, BTF_F_NONAME|BTF_F_ZERO, "0", 0);
160
161 /* typedef struct */
162 TEST_BTF_C(str, atomic_t, 0, {.counter = (int)1,});
163 TEST_BTF(str, atomic_t, BTF_F_NONAME, "{1,}", {.counter = 1,});
164 /* typedef with 0 value should be printed at toplevel */
165 TEST_BTF(str, atomic_t, 0, "(atomic_t){}", {.counter = 0,});
166 TEST_BTF(str, atomic_t, BTF_F_NONAME, "{}", {.counter = 0,});
167 TEST_BTF(str, atomic_t, BTF_F_ZERO, "(atomic_t){.counter = (int)0,}",
168 {.counter = 0,});
169 TEST_BTF(str, atomic_t, BTF_F_NONAME|BTF_F_ZERO,
170 "{0,}", {.counter = 0,});
171
172 /* enum where enum value does (and does not) exist */
173 TEST_BTF_C(str, enum bpf_cmd, 0, BPF_MAP_CREATE);
174 TEST_BTF(str, enum bpf_cmd, 0, "(enum bpf_cmd)BPF_MAP_CREATE", 0);
175 TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME, "BPF_MAP_CREATE",
176 BPF_MAP_CREATE);
177 TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME|BTF_F_ZERO,
178 "BPF_MAP_CREATE", 0);
179
180 TEST_BTF(str, enum bpf_cmd, BTF_F_ZERO, "(enum bpf_cmd)BPF_MAP_CREATE",
181 BPF_MAP_CREATE);
182 TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME|BTF_F_ZERO,
183 "BPF_MAP_CREATE", BPF_MAP_CREATE);
184 TEST_BTF_C(str, enum bpf_cmd, 0, 2000);
185 TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME, "2000", 2000);
186
187 /* simple struct */
188 TEST_BTF_C(str, struct btf_enum, 0,
189 {.name_off = (__u32)3,.val = (__s32)-1,});
190 TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{3,-1,}",
191 { .name_off = 3, .val = -1,});
192 TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{-1,}",
193 { .name_off = 0, .val = -1,});
194 TEST_BTF(str, struct btf_enum, BTF_F_NONAME|BTF_F_ZERO, "{0,-1,}",
195 { .name_off = 0, .val = -1,});
196 /* empty struct should be printed */
197 TEST_BTF(str, struct btf_enum, 0, "(struct btf_enum){}",
198 { .name_off = 0, .val = 0,});
199 TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{}",
200 { .name_off = 0, .val = 0,});
201 TEST_BTF(str, struct btf_enum, BTF_F_ZERO,
202 "(struct btf_enum){.name_off = (__u32)0,.val = (__s32)0,}",
203 { .name_off = 0, .val = 0,});
204
205 /* struct with pointers */
206 TEST_BTF(str, struct list_head, BTF_F_PTR_RAW,
207 "(struct list_head){.next = (struct list_head *)0x0000000000000001,}",
208 { .next = (struct list_head *)1 });
209 /* NULL pointer should not be displayed */
210 TEST_BTF(str, struct list_head, BTF_F_PTR_RAW,
211 "(struct list_head){}",
212 { .next = (struct list_head *)0 });
213
214 /* struct with char array */
215 TEST_BTF(str, struct bpf_prog_info, 0,
216 "(struct bpf_prog_info){.name = (char[])['f','o','o',],}",
217 { .name = "foo",});
218 TEST_BTF(str, struct bpf_prog_info, BTF_F_NONAME,
219 "{['f','o','o',],}",
220 {.name = "foo",});
221 /* leading null char means do not display string */
222 TEST_BTF(str, struct bpf_prog_info, 0,
223 "(struct bpf_prog_info){}",
224 {.name = {'\0', 'f', 'o', 'o'}});
225 /* handle non-printable characters */
226 TEST_BTF(str, struct bpf_prog_info, 0,
227 "(struct bpf_prog_info){.name = (char[])[1,2,3,],}",
228 { .name = {1, 2, 3, 0}});
229
230 /* struct with non-char array */
231 TEST_BTF(str, struct __sk_buff, 0,
232 "(struct __sk_buff){.cb = (__u32[])[1,2,3,4,5,],}",
233 { .cb = {1, 2, 3, 4, 5,},});
234 TEST_BTF(str, struct __sk_buff, BTF_F_NONAME,
235 "{[1,2,3,4,5,],}",
236 { .cb = { 1, 2, 3, 4, 5},});
237 /* For non-char, arrays, show non-zero values only */
238 TEST_BTF(str, struct __sk_buff, 0,
239 "(struct __sk_buff){.cb = (__u32[])[1,],}",
240 { .cb = { 0, 0, 1, 0, 0},});
241
242 /* struct with bitfields */
243 TEST_BTF_C(str, struct bpf_insn, 0,
244 {.code = (__u8)1,.dst_reg = (__u8)0x2,.src_reg = (__u8)0x3,.off = (__s16)4,.imm = (__s32)5,});
245 TEST_BTF(str, struct bpf_insn, BTF_F_NONAME, "{1,0x2,0x3,4,5,}",
246 {.code = 1, .dst_reg = 0x2, .src_reg = 0x3, .off = 4,
247 .imm = 5,});
248 #else
249 skip = true;
250 #endif
251
252 return 0;
253 }
254
255 char _license[] SEC("license") = "GPL";
256