1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2020 Facebook */
3
4 #include <errno.h>
5 #include <linux/err.h>
6 #include <net/if.h>
7 #include <stdio.h>
8 #include <unistd.h>
9
10 #include <bpf/bpf.h>
11 #include <bpf/hashmap.h>
12
13 #include "json_writer.h"
14 #include "main.h"
15
16 static struct hashmap *link_table;
17
link_parse_fd(int * argc,char *** argv)18 static int link_parse_fd(int *argc, char ***argv)
19 {
20 int fd;
21
22 if (is_prefix(**argv, "id")) {
23 unsigned int id;
24 char *endptr;
25
26 NEXT_ARGP();
27
28 id = strtoul(**argv, &endptr, 0);
29 if (*endptr) {
30 p_err("can't parse %s as ID", **argv);
31 return -1;
32 }
33 NEXT_ARGP();
34
35 fd = bpf_link_get_fd_by_id(id);
36 if (fd < 0)
37 p_err("failed to get link with ID %d: %s", id, strerror(errno));
38 return fd;
39 } else if (is_prefix(**argv, "pinned")) {
40 char *path;
41
42 NEXT_ARGP();
43
44 path = **argv;
45 NEXT_ARGP();
46
47 return open_obj_pinned_any(path, BPF_OBJ_LINK);
48 }
49
50 p_err("expected 'id' or 'pinned', got: '%s'?", **argv);
51 return -1;
52 }
53
54 static void
show_link_header_json(struct bpf_link_info * info,json_writer_t * wtr)55 show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr)
56 {
57 const char *link_type_str;
58
59 jsonw_uint_field(wtr, "id", info->id);
60 link_type_str = libbpf_bpf_link_type_str(info->type);
61 if (link_type_str)
62 jsonw_string_field(wtr, "type", link_type_str);
63 else
64 jsonw_uint_field(wtr, "type", info->type);
65
66 jsonw_uint_field(json_wtr, "prog_id", info->prog_id);
67 }
68
show_link_attach_type_json(__u32 attach_type,json_writer_t * wtr)69 static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr)
70 {
71 const char *attach_type_str;
72
73 attach_type_str = libbpf_bpf_attach_type_str(attach_type);
74 if (attach_type_str)
75 jsonw_string_field(wtr, "attach_type", attach_type_str);
76 else
77 jsonw_uint_field(wtr, "attach_type", attach_type);
78 }
79
is_iter_map_target(const char * target_name)80 static bool is_iter_map_target(const char *target_name)
81 {
82 return strcmp(target_name, "bpf_map_elem") == 0 ||
83 strcmp(target_name, "bpf_sk_storage_map") == 0;
84 }
85
is_iter_cgroup_target(const char * target_name)86 static bool is_iter_cgroup_target(const char *target_name)
87 {
88 return strcmp(target_name, "cgroup") == 0;
89 }
90
cgroup_order_string(__u32 order)91 static const char *cgroup_order_string(__u32 order)
92 {
93 switch (order) {
94 case BPF_CGROUP_ITER_ORDER_UNSPEC:
95 return "order_unspec";
96 case BPF_CGROUP_ITER_SELF_ONLY:
97 return "self_only";
98 case BPF_CGROUP_ITER_DESCENDANTS_PRE:
99 return "descendants_pre";
100 case BPF_CGROUP_ITER_DESCENDANTS_POST:
101 return "descendants_post";
102 case BPF_CGROUP_ITER_ANCESTORS_UP:
103 return "ancestors_up";
104 default: /* won't happen */
105 return "unknown";
106 }
107 }
108
is_iter_task_target(const char * target_name)109 static bool is_iter_task_target(const char *target_name)
110 {
111 return strcmp(target_name, "task") == 0 ||
112 strcmp(target_name, "task_file") == 0 ||
113 strcmp(target_name, "task_vma") == 0;
114 }
115
show_iter_json(struct bpf_link_info * info,json_writer_t * wtr)116 static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
117 {
118 const char *target_name = u64_to_ptr(info->iter.target_name);
119
120 jsonw_string_field(wtr, "target_name", target_name);
121
122 if (is_iter_map_target(target_name))
123 jsonw_uint_field(wtr, "map_id", info->iter.map.map_id);
124 else if (is_iter_task_target(target_name)) {
125 if (info->iter.task.tid)
126 jsonw_uint_field(wtr, "tid", info->iter.task.tid);
127 else if (info->iter.task.pid)
128 jsonw_uint_field(wtr, "pid", info->iter.task.pid);
129 }
130
131 if (is_iter_cgroup_target(target_name)) {
132 jsonw_lluint_field(wtr, "cgroup_id", info->iter.cgroup.cgroup_id);
133 jsonw_string_field(wtr, "order",
134 cgroup_order_string(info->iter.cgroup.order));
135 }
136 }
137
get_prog_info(int prog_id,struct bpf_prog_info * info)138 static int get_prog_info(int prog_id, struct bpf_prog_info *info)
139 {
140 __u32 len = sizeof(*info);
141 int err, prog_fd;
142
143 prog_fd = bpf_prog_get_fd_by_id(prog_id);
144 if (prog_fd < 0)
145 return prog_fd;
146
147 memset(info, 0, sizeof(*info));
148 err = bpf_prog_get_info_by_fd(prog_fd, info, &len);
149 if (err)
150 p_err("can't get prog info: %s", strerror(errno));
151 close(prog_fd);
152 return err;
153 }
154
show_link_close_json(int fd,struct bpf_link_info * info)155 static int show_link_close_json(int fd, struct bpf_link_info *info)
156 {
157 struct bpf_prog_info prog_info;
158 const char *prog_type_str;
159 int err;
160
161 jsonw_start_object(json_wtr);
162
163 show_link_header_json(info, json_wtr);
164
165 switch (info->type) {
166 case BPF_LINK_TYPE_RAW_TRACEPOINT:
167 jsonw_string_field(json_wtr, "tp_name",
168 u64_to_ptr(info->raw_tracepoint.tp_name));
169 break;
170 case BPF_LINK_TYPE_TRACING:
171 err = get_prog_info(info->prog_id, &prog_info);
172 if (err)
173 return err;
174
175 prog_type_str = libbpf_bpf_prog_type_str(prog_info.type);
176 /* libbpf will return NULL for variants unknown to it. */
177 if (prog_type_str)
178 jsonw_string_field(json_wtr, "prog_type", prog_type_str);
179 else
180 jsonw_uint_field(json_wtr, "prog_type", prog_info.type);
181
182 show_link_attach_type_json(info->tracing.attach_type,
183 json_wtr);
184 break;
185 case BPF_LINK_TYPE_CGROUP:
186 jsonw_lluint_field(json_wtr, "cgroup_id",
187 info->cgroup.cgroup_id);
188 show_link_attach_type_json(info->cgroup.attach_type, json_wtr);
189 break;
190 case BPF_LINK_TYPE_ITER:
191 show_iter_json(info, json_wtr);
192 break;
193 case BPF_LINK_TYPE_NETNS:
194 jsonw_uint_field(json_wtr, "netns_ino",
195 info->netns.netns_ino);
196 show_link_attach_type_json(info->netns.attach_type, json_wtr);
197 break;
198 default:
199 break;
200 }
201
202 if (!hashmap__empty(link_table)) {
203 struct hashmap_entry *entry;
204
205 jsonw_name(json_wtr, "pinned");
206 jsonw_start_array(json_wtr);
207 hashmap__for_each_key_entry(link_table, entry, info->id)
208 jsonw_string(json_wtr, entry->pvalue);
209 jsonw_end_array(json_wtr);
210 }
211
212 emit_obj_refs_json(refs_table, info->id, json_wtr);
213
214 jsonw_end_object(json_wtr);
215
216 return 0;
217 }
218
show_link_header_plain(struct bpf_link_info * info)219 static void show_link_header_plain(struct bpf_link_info *info)
220 {
221 const char *link_type_str;
222
223 printf("%u: ", info->id);
224 link_type_str = libbpf_bpf_link_type_str(info->type);
225 if (link_type_str)
226 printf("%s ", link_type_str);
227 else
228 printf("type %u ", info->type);
229
230 printf("prog %u ", info->prog_id);
231 }
232
show_link_attach_type_plain(__u32 attach_type)233 static void show_link_attach_type_plain(__u32 attach_type)
234 {
235 const char *attach_type_str;
236
237 attach_type_str = libbpf_bpf_attach_type_str(attach_type);
238 if (attach_type_str)
239 printf("attach_type %s ", attach_type_str);
240 else
241 printf("attach_type %u ", attach_type);
242 }
243
show_iter_plain(struct bpf_link_info * info)244 static void show_iter_plain(struct bpf_link_info *info)
245 {
246 const char *target_name = u64_to_ptr(info->iter.target_name);
247
248 printf("target_name %s ", target_name);
249
250 if (is_iter_map_target(target_name))
251 printf("map_id %u ", info->iter.map.map_id);
252 else if (is_iter_task_target(target_name)) {
253 if (info->iter.task.tid)
254 printf("tid %u ", info->iter.task.tid);
255 else if (info->iter.task.pid)
256 printf("pid %u ", info->iter.task.pid);
257 }
258
259 if (is_iter_cgroup_target(target_name)) {
260 printf("cgroup_id %llu ", info->iter.cgroup.cgroup_id);
261 printf("order %s ",
262 cgroup_order_string(info->iter.cgroup.order));
263 }
264 }
265
show_link_close_plain(int fd,struct bpf_link_info * info)266 static int show_link_close_plain(int fd, struct bpf_link_info *info)
267 {
268 struct bpf_prog_info prog_info;
269 const char *prog_type_str;
270 int err;
271
272 show_link_header_plain(info);
273
274 switch (info->type) {
275 case BPF_LINK_TYPE_RAW_TRACEPOINT:
276 printf("\n\ttp '%s' ",
277 (const char *)u64_to_ptr(info->raw_tracepoint.tp_name));
278 break;
279 case BPF_LINK_TYPE_TRACING:
280 err = get_prog_info(info->prog_id, &prog_info);
281 if (err)
282 return err;
283
284 prog_type_str = libbpf_bpf_prog_type_str(prog_info.type);
285 /* libbpf will return NULL for variants unknown to it. */
286 if (prog_type_str)
287 printf("\n\tprog_type %s ", prog_type_str);
288 else
289 printf("\n\tprog_type %u ", prog_info.type);
290
291 show_link_attach_type_plain(info->tracing.attach_type);
292 break;
293 case BPF_LINK_TYPE_CGROUP:
294 printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id);
295 show_link_attach_type_plain(info->cgroup.attach_type);
296 break;
297 case BPF_LINK_TYPE_ITER:
298 show_iter_plain(info);
299 break;
300 case BPF_LINK_TYPE_NETNS:
301 printf("\n\tnetns_ino %u ", info->netns.netns_ino);
302 show_link_attach_type_plain(info->netns.attach_type);
303 break;
304 default:
305 break;
306 }
307
308 if (!hashmap__empty(link_table)) {
309 struct hashmap_entry *entry;
310
311 hashmap__for_each_key_entry(link_table, entry, info->id)
312 printf("\n\tpinned %s", (char *)entry->pvalue);
313 }
314 emit_obj_refs_plain(refs_table, info->id, "\n\tpids ");
315
316 printf("\n");
317
318 return 0;
319 }
320
do_show_link(int fd)321 static int do_show_link(int fd)
322 {
323 struct bpf_link_info info;
324 __u32 len = sizeof(info);
325 char buf[256];
326 int err;
327
328 memset(&info, 0, sizeof(info));
329 again:
330 err = bpf_link_get_info_by_fd(fd, &info, &len);
331 if (err) {
332 p_err("can't get link info: %s",
333 strerror(errno));
334 close(fd);
335 return err;
336 }
337 if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT &&
338 !info.raw_tracepoint.tp_name) {
339 info.raw_tracepoint.tp_name = (unsigned long)&buf;
340 info.raw_tracepoint.tp_name_len = sizeof(buf);
341 goto again;
342 }
343 if (info.type == BPF_LINK_TYPE_ITER &&
344 !info.iter.target_name) {
345 info.iter.target_name = (unsigned long)&buf;
346 info.iter.target_name_len = sizeof(buf);
347 goto again;
348 }
349
350 if (json_output)
351 show_link_close_json(fd, &info);
352 else
353 show_link_close_plain(fd, &info);
354
355 close(fd);
356 return 0;
357 }
358
do_show(int argc,char ** argv)359 static int do_show(int argc, char **argv)
360 {
361 __u32 id = 0;
362 int err, fd;
363
364 if (show_pinned) {
365 link_table = hashmap__new(hash_fn_for_key_as_id,
366 equal_fn_for_key_as_id, NULL);
367 if (IS_ERR(link_table)) {
368 p_err("failed to create hashmap for pinned paths");
369 return -1;
370 }
371 build_pinned_obj_table(link_table, BPF_OBJ_LINK);
372 }
373 build_obj_refs_table(&refs_table, BPF_OBJ_LINK);
374
375 if (argc == 2) {
376 fd = link_parse_fd(&argc, &argv);
377 if (fd < 0)
378 return fd;
379 return do_show_link(fd);
380 }
381
382 if (argc)
383 return BAD_ARG();
384
385 if (json_output)
386 jsonw_start_array(json_wtr);
387 while (true) {
388 err = bpf_link_get_next_id(id, &id);
389 if (err) {
390 if (errno == ENOENT)
391 break;
392 p_err("can't get next link: %s%s", strerror(errno),
393 errno == EINVAL ? " -- kernel too old?" : "");
394 break;
395 }
396
397 fd = bpf_link_get_fd_by_id(id);
398 if (fd < 0) {
399 if (errno == ENOENT)
400 continue;
401 p_err("can't get link by id (%u): %s",
402 id, strerror(errno));
403 break;
404 }
405
406 err = do_show_link(fd);
407 if (err)
408 break;
409 }
410 if (json_output)
411 jsonw_end_array(json_wtr);
412
413 delete_obj_refs_table(refs_table);
414
415 if (show_pinned)
416 delete_pinned_obj_table(link_table);
417
418 return errno == ENOENT ? 0 : -1;
419 }
420
do_pin(int argc,char ** argv)421 static int do_pin(int argc, char **argv)
422 {
423 int err;
424
425 err = do_pin_any(argc, argv, link_parse_fd);
426 if (!err && json_output)
427 jsonw_null(json_wtr);
428 return err;
429 }
430
do_detach(int argc,char ** argv)431 static int do_detach(int argc, char **argv)
432 {
433 int err, fd;
434
435 if (argc != 2) {
436 p_err("link specifier is invalid or missing\n");
437 return 1;
438 }
439
440 fd = link_parse_fd(&argc, &argv);
441 if (fd < 0)
442 return 1;
443
444 err = bpf_link_detach(fd);
445 if (err)
446 err = -errno;
447 close(fd);
448 if (err) {
449 p_err("failed link detach: %s", strerror(-err));
450 return 1;
451 }
452
453 if (json_output)
454 jsonw_null(json_wtr);
455
456 return 0;
457 }
458
do_help(int argc,char ** argv)459 static int do_help(int argc, char **argv)
460 {
461 if (json_output) {
462 jsonw_null(json_wtr);
463 return 0;
464 }
465
466 fprintf(stderr,
467 "Usage: %1$s %2$s { show | list } [LINK]\n"
468 " %1$s %2$s pin LINK FILE\n"
469 " %1$s %2$s detach LINK\n"
470 " %1$s %2$s help\n"
471 "\n"
472 " " HELP_SPEC_LINK "\n"
473 " " HELP_SPEC_OPTIONS " |\n"
474 " {-f|--bpffs} | {-n|--nomount} }\n"
475 "",
476 bin_name, argv[-2]);
477
478 return 0;
479 }
480
481 static const struct cmd cmds[] = {
482 { "show", do_show },
483 { "list", do_show },
484 { "help", do_help },
485 { "pin", do_pin },
486 { "detach", do_detach },
487 { 0 }
488 };
489
do_link(int argc,char ** argv)490 int do_link(int argc, char **argv)
491 {
492 return cmd_select(cmds, argc, argv, do_help);
493 }
494