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