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1// SPDX-License-Identifier: GPL-2.0
2
3#include <stdio.h>
4#include <stdlib.h>
5#include <signal.h>
6#include <unistd.h>
7#include <stdbool.h>
8#include <string.h>
9#include <stdint.h>
10#include <fcntl.h>
11#include <linux/bpf.h>
12#include <sys/ioctl.h>
13#include <sys/types.h>
14#include <sys/stat.h>
15#include <linux/perf_event.h>
16
17#include <bpf/bpf.h>
18#include <bpf/libbpf.h>
19#include "bpf_util.h"
20#include "perf-sys.h"
21#include "trace_helpers.h"
22
23static struct bpf_program *progs[2];
24static struct bpf_link *links[2];
25
26#define CHECK_PERROR_RET(condition) ({ \
27 int __ret = !!(condition); \
28 if (__ret) { \
29 printf("FAIL: %s:\n", __func__); \
30 perror(" "); \
31 return -1; \
32 } \
33})
34
35#define CHECK_AND_RET(condition) ({ \
36 int __ret = !!(condition); \
37 if (__ret) \
38 return -1; \
39})
40
41static __u64 ptr_to_u64(void *ptr)
42{
43 return (__u64) (unsigned long) ptr;
44}
45
46#define PMU_TYPE_FILE "/sys/bus/event_source/devices/%s/type"
47static int bpf_find_probe_type(const char *event_type)
48{
49 char buf[256];
50 int fd, ret;
51
52 ret = snprintf(buf, sizeof(buf), PMU_TYPE_FILE, event_type);
53 CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf));
54
55 fd = open(buf, O_RDONLY);
56 CHECK_PERROR_RET(fd < 0);
57
58 ret = read(fd, buf, sizeof(buf));
59 close(fd);
60 CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf));
61
62 errno = 0;
63 ret = (int)strtol(buf, NULL, 10);
64 CHECK_PERROR_RET(errno);
65 return ret;
66}
67
68#define PMU_RETPROBE_FILE "/sys/bus/event_source/devices/%s/format/retprobe"
69static int bpf_get_retprobe_bit(const char *event_type)
70{
71 char buf[256];
72 int fd, ret;
73
74 ret = snprintf(buf, sizeof(buf), PMU_RETPROBE_FILE, event_type);
75 CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf));
76
77 fd = open(buf, O_RDONLY);
78 CHECK_PERROR_RET(fd < 0);
79
80 ret = read(fd, buf, sizeof(buf));
81 close(fd);
82 CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf));
83 CHECK_PERROR_RET(strlen(buf) < strlen("config:"));
84
85 errno = 0;
86 ret = (int)strtol(buf + strlen("config:"), NULL, 10);
87 CHECK_PERROR_RET(errno);
88 return ret;
89}
90
91static int test_debug_fs_kprobe(int link_idx, const char *fn_name,
92 __u32 expected_fd_type)
93{
94 __u64 probe_offset, probe_addr;
95 __u32 len, prog_id, fd_type;
96 int err, event_fd;
97 char buf[256];
98
99 len = sizeof(buf);
100 event_fd = bpf_link__fd(links[link_idx]);
101 err = bpf_task_fd_query(getpid(), event_fd, 0, buf, &len,
102 &prog_id, &fd_type, &probe_offset,
103 &probe_addr);
104 if (err < 0) {
105 printf("FAIL: %s, for event_fd idx %d, fn_name %s\n",
106 __func__, link_idx, fn_name);
107 perror(" :");
108 return -1;
109 }
110 if (strcmp(buf, fn_name) != 0 ||
111 fd_type != expected_fd_type ||
112 probe_offset != 0x0 || probe_addr != 0x0) {
113 printf("FAIL: bpf_trace_event_query(event_fd[%d]):\n",
114 link_idx);
115 printf("buf: %s, fd_type: %u, probe_offset: 0x%llx,"
116 " probe_addr: 0x%llx\n",
117 buf, fd_type, probe_offset, probe_addr);
118 return -1;
119 }
120 return 0;
121}
122
123static int test_nondebug_fs_kuprobe_common(const char *event_type,
124 const char *name, __u64 offset, __u64 addr, bool is_return,
125 char *buf, __u32 *buf_len, __u32 *prog_id, __u32 *fd_type,
126 __u64 *probe_offset, __u64 *probe_addr)
127{
128 int is_return_bit = bpf_get_retprobe_bit(event_type);
129 int type = bpf_find_probe_type(event_type);
130 struct perf_event_attr attr = {};
131 struct bpf_link *link;
132 int fd, err = -1;
133
134 if (type < 0 || is_return_bit < 0) {
135 printf("FAIL: %s incorrect type (%d) or is_return_bit (%d)\n",
136 __func__, type, is_return_bit);
137 return err;
138 }
139
140 attr.sample_period = 1;
141 attr.wakeup_events = 1;
142 if (is_return)
143 attr.config |= 1 << is_return_bit;
144
145 if (name) {
146 attr.config1 = ptr_to_u64((void *)name);
147 attr.config2 = offset;
148 } else {
149 attr.config1 = 0;
150 attr.config2 = addr;
151 }
152 attr.size = sizeof(attr);
153 attr.type = type;
154
155 fd = sys_perf_event_open(&attr, -1, 0, -1, 0);
156 link = bpf_program__attach_perf_event(progs[0], fd);
157 if (libbpf_get_error(link)) {
158 printf("ERROR: bpf_program__attach_perf_event failed\n");
159 link = NULL;
160 close(fd);
161 goto cleanup;
162 }
163
164 CHECK_PERROR_RET(bpf_task_fd_query(getpid(), fd, 0, buf, buf_len,
165 prog_id, fd_type, probe_offset, probe_addr) < 0);
166 err = 0;
167
168cleanup:
169 bpf_link__destroy(link);
170 return err;
171}
172
173static int test_nondebug_fs_probe(const char *event_type, const char *name,
174 __u64 offset, __u64 addr, bool is_return,
175 __u32 expected_fd_type,
176 __u32 expected_ret_fd_type,
177 char *buf, __u32 buf_len)
178{
179 __u64 probe_offset, probe_addr;
180 __u32 prog_id, fd_type;
181 int err;
182
183 err = test_nondebug_fs_kuprobe_common(event_type, name,
184 offset, addr, is_return,
185 buf, &buf_len, &prog_id,
186 &fd_type, &probe_offset,
187 &probe_addr);
188 if (err < 0) {
189 printf("FAIL: %s, "
190 "for name %s, offset 0x%llx, addr 0x%llx, is_return %d\n",
191 __func__, name ? name : "", offset, addr, is_return);
192 perror(" :");
193 return -1;
194 }
195 if ((is_return && fd_type != expected_ret_fd_type) ||
196 (!is_return && fd_type != expected_fd_type)) {
197 printf("FAIL: %s, incorrect fd_type %u\n",
198 __func__, fd_type);
199 return -1;
200 }
201 if (name) {
202 if (strcmp(name, buf) != 0) {
203 printf("FAIL: %s, incorrect buf %s\n", __func__, buf);
204 return -1;
205 }
206 if (probe_offset != offset) {
207 printf("FAIL: %s, incorrect probe_offset 0x%llx\n",
208 __func__, probe_offset);
209 return -1;
210 }
211 } else {
212 if (buf_len != 0) {
213 printf("FAIL: %s, incorrect buf %p\n",
214 __func__, buf);
215 return -1;
216 }
217
218 if (probe_addr != addr) {
219 printf("FAIL: %s, incorrect probe_addr 0x%llx\n",
220 __func__, probe_addr);
221 return -1;
222 }
223 }
224 return 0;
225}
226
227static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return)
228{
229 char buf[256], event_alias[sizeof("test_1234567890")];
230 const char *event_type = "uprobe";
231 struct perf_event_attr attr = {};
232 __u64 probe_offset, probe_addr;
233 __u32 len, prog_id, fd_type;
234 int err = -1, res, kfd, efd;
235 struct bpf_link *link;
236 ssize_t bytes;
237
238 snprintf(buf, sizeof(buf), "/sys/kernel/tracing/%s_events",
239 event_type);
240 kfd = open(buf, O_WRONLY | O_TRUNC, 0);
241 CHECK_PERROR_RET(kfd < 0);
242
243 res = snprintf(event_alias, sizeof(event_alias), "test_%d", getpid());
244 CHECK_PERROR_RET(res < 0 || res >= sizeof(event_alias));
245
246 res = snprintf(buf, sizeof(buf), "%c:%ss/%s %s:0x%lx",
247 is_return ? 'r' : 'p', event_type, event_alias,
248 binary_path, offset);
249 CHECK_PERROR_RET(res < 0 || res >= sizeof(buf));
250 CHECK_PERROR_RET(write(kfd, buf, strlen(buf)) < 0);
251
252 close(kfd);
253 kfd = -1;
254
255 snprintf(buf, sizeof(buf), "/sys/kernel/tracing/events/%ss/%s/id",
256 event_type, event_alias);
257 efd = open(buf, O_RDONLY, 0);
258 CHECK_PERROR_RET(efd < 0);
259
260 bytes = read(efd, buf, sizeof(buf));
261 CHECK_PERROR_RET(bytes <= 0 || bytes >= sizeof(buf));
262 close(efd);
263 buf[bytes] = '\0';
264
265 attr.config = strtol(buf, NULL, 0);
266 attr.type = PERF_TYPE_TRACEPOINT;
267 attr.sample_period = 1;
268 attr.wakeup_events = 1;
269
270 kfd = sys_perf_event_open(&attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
271 link = bpf_program__attach_perf_event(progs[0], kfd);
272 if (libbpf_get_error(link)) {
273 printf("ERROR: bpf_program__attach_perf_event failed\n");
274 link = NULL;
275 close(kfd);
276 goto cleanup;
277 }
278
279 len = sizeof(buf);
280 err = bpf_task_fd_query(getpid(), kfd, 0, buf, &len,
281 &prog_id, &fd_type, &probe_offset,
282 &probe_addr);
283 if (err < 0) {
284 printf("FAIL: %s, binary_path %s\n", __func__, binary_path);
285 perror(" :");
286 return -1;
287 }
288 if ((is_return && fd_type != BPF_FD_TYPE_URETPROBE) ||
289 (!is_return && fd_type != BPF_FD_TYPE_UPROBE)) {
290 printf("FAIL: %s, incorrect fd_type %u\n", __func__,
291 fd_type);
292 return -1;
293 }
294 if (strcmp(binary_path, buf) != 0) {
295 printf("FAIL: %s, incorrect buf %s\n", __func__, buf);
296 return -1;
297 }
298 if (probe_offset != offset) {
299 printf("FAIL: %s, incorrect probe_offset 0x%llx\n", __func__,
300 probe_offset);
301 return -1;
302 }
303 err = 0;
304
305cleanup:
306 bpf_link__destroy(link);
307 return err;
308}
309
310int main(int argc, char **argv)
311{
312 extern char __executable_start;
313 char filename[256], buf[256];
314 __u64 uprobe_file_offset;
315 struct bpf_program *prog;
316 struct bpf_object *obj;
317 int i = 0, err = -1;
318
319 if (load_kallsyms()) {
320 printf("failed to process /proc/kallsyms\n");
321 return err;
322 }
323
324 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
325 obj = bpf_object__open_file(filename, NULL);
326 if (libbpf_get_error(obj)) {
327 fprintf(stderr, "ERROR: opening BPF object file failed\n");
328 return err;
329 }
330
331 /* load BPF program */
332 if (bpf_object__load(obj)) {
333 fprintf(stderr, "ERROR: loading BPF object file failed\n");
334 goto cleanup;
335 }
336
337 bpf_object__for_each_program(prog, obj) {
338 progs[i] = prog;
339 links[i] = bpf_program__attach(progs[i]);
340 if (libbpf_get_error(links[i])) {
341 fprintf(stderr, "ERROR: bpf_program__attach failed\n");
342 links[i] = NULL;
343 goto cleanup;
344 }
345 i++;
346 }
347
348 /* test two functions in the corresponding *_kern.c file */
349 CHECK_AND_RET(test_debug_fs_kprobe(0, "blk_mq_start_request",
350 BPF_FD_TYPE_KPROBE));
351 CHECK_AND_RET(test_debug_fs_kprobe(1, "__blk_account_io_done",
352 BPF_FD_TYPE_KRETPROBE));
353
354 /* test nondebug fs kprobe */
355 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x0, 0x0,
356 false, BPF_FD_TYPE_KPROBE,
357 BPF_FD_TYPE_KRETPROBE,
358 buf, sizeof(buf)));
359#ifdef __x86_64__
360 /* set a kprobe on "bpf_check + 0x5", which is x64 specific */
361 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x5, 0x0,
362 false, BPF_FD_TYPE_KPROBE,
363 BPF_FD_TYPE_KRETPROBE,
364 buf, sizeof(buf)));
365#endif
366 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x0, 0x0,
367 true, BPF_FD_TYPE_KPROBE,
368 BPF_FD_TYPE_KRETPROBE,
369 buf, sizeof(buf)));
370 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0,
371 ksym_get_addr("bpf_check"), false,
372 BPF_FD_TYPE_KPROBE,
373 BPF_FD_TYPE_KRETPROBE,
374 buf, sizeof(buf)));
375 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0,
376 ksym_get_addr("bpf_check"), false,
377 BPF_FD_TYPE_KPROBE,
378 BPF_FD_TYPE_KRETPROBE,
379 NULL, 0));
380 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0,
381 ksym_get_addr("bpf_check"), true,
382 BPF_FD_TYPE_KPROBE,
383 BPF_FD_TYPE_KRETPROBE,
384 buf, sizeof(buf)));
385 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0,
386 ksym_get_addr("bpf_check"), true,
387 BPF_FD_TYPE_KPROBE,
388 BPF_FD_TYPE_KRETPROBE,
389 0, 0));
390
391 /* test nondebug fs uprobe */
392 /* the calculation of uprobe file offset is based on gcc 7.3.1 on x64
393 * and the default linker script, which defines __executable_start as
394 * the start of the .text section. The calculation could be different
395 * on different systems with different compilers. The right way is
396 * to parse the ELF file. We took a shortcut here.
397 */
398 uprobe_file_offset = (unsigned long)main - (unsigned long)&__executable_start;
399 CHECK_AND_RET(test_nondebug_fs_probe("uprobe", (char *)argv[0],
400 uprobe_file_offset, 0x0, false,
401 BPF_FD_TYPE_UPROBE,
402 BPF_FD_TYPE_URETPROBE,
403 buf, sizeof(buf)));
404 CHECK_AND_RET(test_nondebug_fs_probe("uprobe", (char *)argv[0],
405 uprobe_file_offset, 0x0, true,
406 BPF_FD_TYPE_UPROBE,
407 BPF_FD_TYPE_URETPROBE,
408 buf, sizeof(buf)));
409
410 /* test debug fs uprobe */
411 CHECK_AND_RET(test_debug_fs_uprobe((char *)argv[0], uprobe_file_offset,
412 false));
413 CHECK_AND_RET(test_debug_fs_uprobe((char *)argv[0], uprobe_file_offset,
414 true));
415 err = 0;
416
417cleanup:
418 for (i--; i >= 0; i--)
419 bpf_link__destroy(links[i]);
420
421 bpf_object__close(obj);
422 return err;
423}