Skip to content

Commit 076a95f

Browse files
alan-maguireAlexei Starovoitov
alan-maguire
authored and
Alexei Starovoitov
committed
selftests/bpf: Add bpf_snprintf_btf helper tests
Tests verifying snprintf()ing of various data structures, flags combinations using a tp_btf program. Tests are skipped if __builtin_btf_type_id is not available to retrieve BTF type ids. Signed-off-by: Alan Maguire <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
1 parent c4d0bfb commit 076a95f

File tree

2 files changed

+309
-0
lines changed

2 files changed

+309
-0
lines changed

‎tools/testing/selftests/bpf/prog_tests/snprintf_btf.c

Lines changed: 60 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,60 @@
1+
// SPDX-License-Identifier: GPL-2.0
2+
#include <test_progs.h>
3+
#include <linux/btf.h>
4+
#include "netif_receive_skb.skel.h"
5+
6+
/* Demonstrate that bpf_snprintf_btf succeeds and that various data types
7+
* are formatted correctly.
8+
*/
9+
void test_snprintf_btf(void)
10+
{
11+
struct netif_receive_skb *skel;
12+
struct netif_receive_skb__bss *bss;
13+
int err, duration = 0;
14+
15+
skel = netif_receive_skb__open();
16+
if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
17+
return;
18+
19+
err = netif_receive_skb__load(skel);
20+
if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
21+
goto cleanup;
22+
23+
bss = skel->bss;
24+
25+
err = netif_receive_skb__attach(skel);
26+
if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
27+
goto cleanup;
28+
29+
/* generate receive event */
30+
system("ping -c 1 127.0.0.1 > /dev/null");
31+
32+
if (bss->skip) {
33+
printf("%s:SKIP:no __builtin_btf_type_id\n", __func__);
34+
test__skip();
35+
goto cleanup;
36+
}
37+
38+
/*
39+
* Make sure netif_receive_skb program was triggered
40+
* and it set expected return values from bpf_trace_printk()s
41+
* and all tests ran.
42+
*/
43+
if (CHECK(bss->ret <= 0,
44+
"bpf_snprintf_btf: got return value",
45+
"ret <= 0 %ld test %d\n", bss->ret, bss->ran_subtests))
46+
goto cleanup;
47+
48+
if (CHECK(bss->ran_subtests == 0, "check if subtests ran",
49+
"no subtests ran, did BPF program run?"))
50+
goto cleanup;
51+
52+
if (CHECK(bss->num_subtests != bss->ran_subtests,
53+
"check all subtests ran",
54+
"only ran %d of %d tests\n", bss->num_subtests,
55+
bss->ran_subtests))
56+
goto cleanup;
57+
58+
cleanup:
59+
netif_receive_skb__destroy(skel);
60+
}

‎tools/testing/selftests/bpf/progs/netif_receive_skb.c

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

0 commit comments

Comments
 (0)