GNU Linux-libre 6.6.15-gnu
[releases.git] / samples / bpf / task_fd_query_user.c
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
23 static struct bpf_program *progs[2];
24 static 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
41 static __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"
47 static 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"
69 static 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
91 static 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
123 static 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
168 cleanup:
169         bpf_link__destroy(link);
170         return err;
171 }
172
173 static 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
227 static 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
305 cleanup:
306         bpf_link__destroy(link);
307         return err;
308 }
309
310 int 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
417 cleanup:
418         for (i--; i >= 0; i--)
419                 bpf_link__destroy(links[i]);
420
421         bpf_object__close(obj);
422         return err;
423 }