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