1
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/resource.h>
14#include <sys/types.h>
15#include <sys/stat.h>
16#include <linux/perf_event.h>
17
18#include <bpf/bpf.h>
19#include <bpf/libbpf.h>
20#include "bpf_util.h"
21#include "perf-sys.h"
22#include "trace_helpers.h"
23
24static struct bpf_program *progs[2];
25static struct bpf_link *links[2];
26
27#define CHECK_PERROR_RET(condition) ({ \
28 int __ret = !!(condition); \
29 if (__ret) { \
30 printf("FAIL: %s:\n", __func__); \
31 perror(" "); \
32 return -1; \
33 } \
34})
35
36#define CHECK_AND_RET(condition) ({ \
37 int __ret = !!(condition); \
38 if (__ret) \
39 return -1; \
40})
41
42static __u64 ptr_to_u64(void *ptr)
43{
44 return (__u64) (unsigned long) ptr;
45}
46
47#define PMU_TYPE_FILE "/sys/bus/event_source/devices/%s/type"
48static int bpf_find_probe_type(const char *event_type)
49{
50 char buf[256];
51 int fd, ret;
52
53 ret = snprintf(buf, sizeof(buf), PMU_TYPE_FILE, event_type);
54 CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf));
55
56 fd = open(buf, O_RDONLY);
57 CHECK_PERROR_RET(fd < 0);
58
59 ret = read(fd, buf, sizeof(buf));
60 close(fd);
61 CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf));
62
63 errno = 0;
64 ret = (int)strtol(buf, NULL, 10);
65 CHECK_PERROR_RET(errno);
66 return ret;
67}
68
69#define PMU_RETPROBE_FILE "/sys/bus/event_source/devices/%s/format/retprobe"
70static int bpf_get_retprobe_bit(const char *event_type)
71{
72 char buf[256];
73 int fd, ret;
74
75 ret = snprintf(buf, sizeof(buf), PMU_RETPROBE_FILE, event_type);
76 CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf));
77
78 fd = open(buf, O_RDONLY);
79 CHECK_PERROR_RET(fd < 0);
80
81 ret = read(fd, buf, sizeof(buf));
82 close(fd);
83 CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf));
84 CHECK_PERROR_RET(strlen(buf) < strlen("config:"));
85
86 errno = 0;
87 ret = (int)strtol(buf + strlen("config:"), NULL, 10);
88 CHECK_PERROR_RET(errno);
89 return ret;
90}
91
92static int test_debug_fs_kprobe(int link_idx, const char *fn_name,
93 __u32 expected_fd_type)
94{
95 __u64 probe_offset, probe_addr;
96 __u32 len, prog_id, fd_type;
97 int err, event_fd;
98 char buf[256];
99
100 len = sizeof(buf);
101 event_fd = bpf_link__fd(links[link_idx]);
102 err = bpf_task_fd_query(getpid(), event_fd, 0, buf, &len,
103 &prog_id, &fd_type, &probe_offset,
104 &probe_addr);
105 if (err < 0) {
106 printf("FAIL: %s, for event_fd idx %d, fn_name %s\n",
107 __func__, link_idx, fn_name);
108 perror(" :");
109 return -1;
110 }
111 if (strcmp(buf, fn_name) != 0 ||
112 fd_type != expected_fd_type ||
113 probe_offset != 0x0 || probe_addr != 0x0) {
114 printf("FAIL: bpf_trace_event_query(event_fd[%d]):\n",
115 link_idx);
116 printf("buf: %s, fd_type: %u, probe_offset: 0x%llx,"
117 " probe_addr: 0x%llx\n",
118 buf, fd_type, probe_offset, probe_addr);
119 return -1;
120 }
121 return 0;
122}
123
124static int test_nondebug_fs_kuprobe_common(const char *event_type,
125 const char *name, __u64 offset, __u64 addr, bool is_return,
126 char *buf, __u32 *buf_len, __u32 *prog_id, __u32 *fd_type,
127 __u64 *probe_offset, __u64 *probe_addr)
128{
129 int is_return_bit = bpf_get_retprobe_bit(event_type);
130 int type = bpf_find_probe_type(event_type);
131 struct perf_event_attr attr = {};
132 struct bpf_link *link;
133 int fd, err = -1;
134
135 if (type < 0 || is_return_bit < 0) {
136 printf("FAIL: %s incorrect type (%d) or is_return_bit (%d)\n",
137 __func__, type, is_return_bit);
138 return err;
139 }
140
141 attr.sample_period = 1;
142 attr.wakeup_events = 1;
143 if (is_return)
144 attr.config |= 1 << is_return_bit;
145
146 if (name) {
147 attr.config1 = ptr_to_u64((void *)name);
148 attr.config2 = offset;
149 } else {
150 attr.config1 = 0;
151 attr.config2 = addr;
152 }
153 attr.size = sizeof(attr);
154 attr.type = type;
155
156 fd = sys_perf_event_open(&attr, -1, 0, -1, 0);
157 link = bpf_program__attach_perf_event(progs[0], fd);
158 if (libbpf_get_error(link)) {
159 printf("ERROR: bpf_program__attach_perf_event failed\n");
160 link = NULL;
161 close(fd);
162 goto cleanup;
163 }
164
165 CHECK_PERROR_RET(bpf_task_fd_query(getpid(), fd, 0, buf, buf_len,
166 prog_id, fd_type, probe_offset, probe_addr) < 0);
167 err = 0;
168
169cleanup:
170 bpf_link__destroy(link);
171 return err;
172}
173
174static int test_nondebug_fs_probe(const char *event_type, const char *name,
175 __u64 offset, __u64 addr, bool is_return,
176 __u32 expected_fd_type,
177 __u32 expected_ret_fd_type,
178 char *buf, __u32 buf_len)
179{
180 __u64 probe_offset, probe_addr;
181 __u32 prog_id, fd_type;
182 int err;
183
184 err = test_nondebug_fs_kuprobe_common(event_type, name,
185 offset, addr, is_return,
186 buf, &buf_len, &prog_id,
187 &fd_type, &probe_offset,
188 &probe_addr);
189 if (err < 0) {
190 printf("FAIL: %s, "
191 "for name %s, offset 0x%llx, addr 0x%llx, is_return %d\n",
192 __func__, name ? name : "", offset, addr, is_return);
193 perror(" :");
194 return -1;
195 }
196 if ((is_return && fd_type != expected_ret_fd_type) ||
197 (!is_return && fd_type != expected_fd_type)) {
198 printf("FAIL: %s, incorrect fd_type %u\n",
199 __func__, fd_type);
200 return -1;
201 }
202 if (name) {
203 if (strcmp(name, buf) != 0) {
204 printf("FAIL: %s, incorrect buf %s\n", __func__, buf);
205 return -1;
206 }
207 if (probe_offset != offset) {
208 printf("FAIL: %s, incorrect probe_offset 0x%llx\n",
209 __func__, probe_offset);
210 return -1;
211 }
212 } else {
213 if (buf_len != 0) {
214 printf("FAIL: %s, incorrect buf %p\n",
215 __func__, buf);
216 return -1;
217 }
218
219 if (probe_addr != addr) {
220 printf("FAIL: %s, incorrect probe_addr 0x%llx\n",
221 __func__, probe_addr);
222 return -1;
223 }
224 }
225 return 0;
226}
227
228static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return)
229{
230 char buf[256], event_alias[sizeof("test_1234567890")];
231 const char *event_type = "uprobe";
232 struct perf_event_attr attr = {};
233 __u64 probe_offset, probe_addr;
234 __u32 len, prog_id, fd_type;
235 int err = -1, res, kfd, efd;
236 struct bpf_link *link;
237 ssize_t bytes;
238
239 snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/%s_events",
240 event_type);
241 kfd = open(buf, O_WRONLY | O_TRUNC, 0);
242 CHECK_PERROR_RET(kfd < 0);
243
244 res = snprintf(event_alias, sizeof(event_alias), "test_%d", getpid());
245 CHECK_PERROR_RET(res < 0 || res >= sizeof(event_alias));
246
247 res = snprintf(buf, sizeof(buf), "%c:%ss/%s %s:0x%lx",
248 is_return ? 'r' : 'p', event_type, event_alias,
249 binary_path, offset);
250 CHECK_PERROR_RET(res < 0 || res >= sizeof(buf));
251 CHECK_PERROR_RET(write(kfd, buf, strlen(buf)) < 0);
252
253 close(kfd);
254 kfd = -1;
255
256 snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s/id",
257 event_type, event_alias);
258 efd = open(buf, O_RDONLY, 0);
259 CHECK_PERROR_RET(efd < 0);
260
261 bytes = read(efd, buf, sizeof(buf));
262 CHECK_PERROR_RET(bytes <= 0 || bytes >= sizeof(buf));
263 close(efd);
264 buf[bytes] = '\0';
265
266 attr.config = strtol(buf, NULL, 0);
267 attr.type = PERF_TYPE_TRACEPOINT;
268 attr.sample_period = 1;
269 attr.wakeup_events = 1;
270
271 kfd = sys_perf_event_open(&attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
272 link = bpf_program__attach_perf_event(progs[0], kfd);
273 if (libbpf_get_error(link)) {
274 printf("ERROR: bpf_program__attach_perf_event failed\n");
275 link = NULL;
276 close(kfd);
277 goto cleanup;
278 }
279
280 len = sizeof(buf);
281 err = bpf_task_fd_query(getpid(), kfd, 0, buf, &len,
282 &prog_id, &fd_type, &probe_offset,
283 &probe_addr);
284 if (err < 0) {
285 printf("FAIL: %s, binary_path %s\n", __func__, binary_path);
286 perror(" :");
287 return -1;
288 }
289 if ((is_return && fd_type != BPF_FD_TYPE_URETPROBE) ||
290 (!is_return && fd_type != BPF_FD_TYPE_UPROBE)) {
291 printf("FAIL: %s, incorrect fd_type %u\n", __func__,
292 fd_type);
293 return -1;
294 }
295 if (strcmp(binary_path, buf) != 0) {
296 printf("FAIL: %s, incorrect buf %s\n", __func__, buf);
297 return -1;
298 }
299 if (probe_offset != offset) {
300 printf("FAIL: %s, incorrect probe_offset 0x%llx\n", __func__,
301 probe_offset);
302 return -1;
303 }
304 err = 0;
305
306cleanup:
307 bpf_link__destroy(link);
308 return err;
309}
310
311int main(int argc, char **argv)
312{
313 extern char __executable_start;
314 char filename[256], buf[256];
315 __u64 uprobe_file_offset;
316 struct bpf_program *prog;
317 struct bpf_object *obj;
318 int i = 0, err = -1;
319
320 if (load_kallsyms()) {
321 printf("failed to process /proc/kallsyms\n");
322 return err;
323 }
324
325 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
326 obj = bpf_object__open_file(filename, NULL);
327 if (libbpf_get_error(obj)) {
328 fprintf(stderr, "ERROR: opening BPF object file failed\n");
329 return err;
330 }
331
332
333 if (bpf_object__load(obj)) {
334 fprintf(stderr, "ERROR: loading BPF object file failed\n");
335 goto cleanup;
336 }
337
338 bpf_object__for_each_program(prog, obj) {
339 progs[i] = prog;
340 links[i] = bpf_program__attach(progs[i]);
341 if (libbpf_get_error(links[i])) {
342 fprintf(stderr, "ERROR: bpf_program__attach failed\n");
343 links[i] = NULL;
344 goto cleanup;
345 }
346 i++;
347 }
348
349
350 CHECK_AND_RET(test_debug_fs_kprobe(0, "blk_mq_start_request",
351 BPF_FD_TYPE_KPROBE));
352 CHECK_AND_RET(test_debug_fs_kprobe(1, "blk_account_io_done",
353 BPF_FD_TYPE_KRETPROBE));
354
355
356 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x0, 0x0,
357 false, BPF_FD_TYPE_KPROBE,
358 BPF_FD_TYPE_KRETPROBE,
359 buf, sizeof(buf)));
360#ifdef __x86_64__
361
362 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x5, 0x0,
363 false, BPF_FD_TYPE_KPROBE,
364 BPF_FD_TYPE_KRETPROBE,
365 buf, sizeof(buf)));
366#endif
367 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x0, 0x0,
368 true, BPF_FD_TYPE_KPROBE,
369 BPF_FD_TYPE_KRETPROBE,
370 buf, sizeof(buf)));
371 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0,
372 ksym_get_addr("bpf_check"), false,
373 BPF_FD_TYPE_KPROBE,
374 BPF_FD_TYPE_KRETPROBE,
375 buf, sizeof(buf)));
376 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0,
377 ksym_get_addr("bpf_check"), false,
378 BPF_FD_TYPE_KPROBE,
379 BPF_FD_TYPE_KRETPROBE,
380 NULL, 0));
381 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0,
382 ksym_get_addr("bpf_check"), true,
383 BPF_FD_TYPE_KPROBE,
384 BPF_FD_TYPE_KRETPROBE,
385 buf, sizeof(buf)));
386 CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0,
387 ksym_get_addr("bpf_check"), true,
388 BPF_FD_TYPE_KPROBE,
389 BPF_FD_TYPE_KRETPROBE,
390 0, 0));
391
392
393
394
395
396
397
398
399 uprobe_file_offset = (unsigned long)main - (unsigned long)&__executable_start;
400 CHECK_AND_RET(test_nondebug_fs_probe("uprobe", (char *)argv[0],
401 uprobe_file_offset, 0x0, false,
402 BPF_FD_TYPE_UPROBE,
403 BPF_FD_TYPE_URETPROBE,
404 buf, sizeof(buf)));
405 CHECK_AND_RET(test_nondebug_fs_probe("uprobe", (char *)argv[0],
406 uprobe_file_offset, 0x0, true,
407 BPF_FD_TYPE_UPROBE,
408 BPF_FD_TYPE_URETPROBE,
409 buf, sizeof(buf)));
410
411
412 CHECK_AND_RET(test_debug_fs_uprobe((char *)argv[0], uprobe_file_offset,
413 false));
414 CHECK_AND_RET(test_debug_fs_uprobe((char *)argv[0], uprobe_file_offset,
415 true));
416 err = 0;
417
418cleanup:
419 for (i--; i >= 0; i--)
420 bpf_link__destroy(links[i]);
421
422 bpf_object__close(obj);
423 return err;
424}
425
