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1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2// Copyright (C) 2017 Facebook
3// Author: Roman Gushchin <guro@fb.com>
4
5#define _XOPEN_SOURCE 500
6#include <errno.h>
7#include <fcntl.h>
8#include <ftw.h>
9#include <mntent.h>
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>
13#include <sys/stat.h>
14#include <sys/types.h>
15#include <unistd.h>
16
17#include <bpf.h>
18
19#include "main.h"
20
21#define HELP_SPEC_ATTACH_FLAGS \
22 "ATTACH_FLAGS := { multi | override }"
23
24#define HELP_SPEC_ATTACH_TYPES \
25 " ATTACH_TYPE := { ingress | egress | sock_create |\n" \
26 " sock_ops | device | bind4 | bind6 |\n" \
27 " post_bind4 | post_bind6 | connect4 |\n" \
28 " connect6 | sendmsg4 | sendmsg6 |\n" \
29 " recvmsg4 | recvmsg6 | sysctl |\n" \
30 " getsockopt | setsockopt }"
31
32static unsigned int query_flags;
33
34static const char * const attach_type_strings[] = {
35 [BPF_CGROUP_INET_INGRESS] = "ingress",
36 [BPF_CGROUP_INET_EGRESS] = "egress",
37 [BPF_CGROUP_INET_SOCK_CREATE] = "sock_create",
38 [BPF_CGROUP_SOCK_OPS] = "sock_ops",
39 [BPF_CGROUP_DEVICE] = "device",
40 [BPF_CGROUP_INET4_BIND] = "bind4",
41 [BPF_CGROUP_INET6_BIND] = "bind6",
42 [BPF_CGROUP_INET4_CONNECT] = "connect4",
43 [BPF_CGROUP_INET6_CONNECT] = "connect6",
44 [BPF_CGROUP_INET4_POST_BIND] = "post_bind4",
45 [BPF_CGROUP_INET6_POST_BIND] = "post_bind6",
46 [BPF_CGROUP_UDP4_SENDMSG] = "sendmsg4",
47 [BPF_CGROUP_UDP6_SENDMSG] = "sendmsg6",
48 [BPF_CGROUP_SYSCTL] = "sysctl",
49 [BPF_CGROUP_UDP4_RECVMSG] = "recvmsg4",
50 [BPF_CGROUP_UDP6_RECVMSG] = "recvmsg6",
51 [BPF_CGROUP_GETSOCKOPT] = "getsockopt",
52 [BPF_CGROUP_SETSOCKOPT] = "setsockopt",
53 [__MAX_BPF_ATTACH_TYPE] = NULL,
54};
55
56static enum bpf_attach_type parse_attach_type(const char *str)
57{
58 enum bpf_attach_type type;
59
60 for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
61 if (attach_type_strings[type] &&
62 is_prefix(str, attach_type_strings[type]))
63 return type;
64 }
65
66 return __MAX_BPF_ATTACH_TYPE;
67}
68
69static int show_bpf_prog(int id, const char *attach_type_str,
70 const char *attach_flags_str,
71 int level)
72{
73 struct bpf_prog_info info = {};
74 __u32 info_len = sizeof(info);
75 int prog_fd;
76
77 prog_fd = bpf_prog_get_fd_by_id(id);
78 if (prog_fd < 0)
79 return -1;
80
81 if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) {
82 close(prog_fd);
83 return -1;
84 }
85
86 if (json_output) {
87 jsonw_start_object(json_wtr);
88 jsonw_uint_field(json_wtr, "id", info.id);
89 jsonw_string_field(json_wtr, "attach_type",
90 attach_type_str);
91 jsonw_string_field(json_wtr, "attach_flags",
92 attach_flags_str);
93 jsonw_string_field(json_wtr, "name", info.name);
94 jsonw_end_object(json_wtr);
95 } else {
96 printf("%s%-8u %-15s %-15s %-15s\n", level ? " " : "",
97 info.id,
98 attach_type_str,
99 attach_flags_str,
100 info.name);
101 }
102
103 close(prog_fd);
104 return 0;
105}
106
107static int count_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
108{
109 __u32 prog_cnt = 0;
110 int ret;
111
112 ret = bpf_prog_query(cgroup_fd, type, query_flags, NULL,
113 NULL, &prog_cnt);
114 if (ret)
115 return -1;
116
117 return prog_cnt;
118}
119
120static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
121 int level)
122{
123 const char *attach_flags_str;
124 __u32 prog_ids[1024] = {0};
125 __u32 prog_cnt, iter;
126 __u32 attach_flags;
127 char buf[32];
128 int ret;
129
130 prog_cnt = ARRAY_SIZE(prog_ids);
131 ret = bpf_prog_query(cgroup_fd, type, query_flags, &attach_flags,
132 prog_ids, &prog_cnt);
133 if (ret)
134 return ret;
135
136 if (prog_cnt == 0)
137 return 0;
138
139 switch (attach_flags) {
140 case BPF_F_ALLOW_MULTI:
141 attach_flags_str = "multi";
142 break;
143 case BPF_F_ALLOW_OVERRIDE:
144 attach_flags_str = "override";
145 break;
146 case 0:
147 attach_flags_str = "";
148 break;
149 default:
150 snprintf(buf, sizeof(buf), "unknown(%x)", attach_flags);
151 attach_flags_str = buf;
152 }
153
154 for (iter = 0; iter < prog_cnt; iter++)
155 show_bpf_prog(prog_ids[iter], attach_type_strings[type],
156 attach_flags_str, level);
157
158 return 0;
159}
160
161static int do_show(int argc, char **argv)
162{
163 enum bpf_attach_type type;
164 const char *path;
165 int cgroup_fd;
166 int ret = -1;
167
168 query_flags = 0;
169
170 if (!REQ_ARGS(1))
171 return -1;
172 path = GET_ARG();
173
174 while (argc) {
175 if (is_prefix(*argv, "effective")) {
176 if (query_flags & BPF_F_QUERY_EFFECTIVE) {
177 p_err("duplicated argument: %s", *argv);
178 return -1;
179 }
180 query_flags |= BPF_F_QUERY_EFFECTIVE;
181 NEXT_ARG();
182 } else {
183 p_err("expected no more arguments, 'effective', got: '%s'?",
184 *argv);
185 return -1;
186 }
187 }
188
189 cgroup_fd = open(path, O_RDONLY);
190 if (cgroup_fd < 0) {
191 p_err("can't open cgroup %s", path);
192 goto exit;
193 }
194
195 if (json_output)
196 jsonw_start_array(json_wtr);
197 else
198 printf("%-8s %-15s %-15s %-15s\n", "ID", "AttachType",
199 "AttachFlags", "Name");
200
201 for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
202 /*
203 * Not all attach types may be supported, so it's expected,
204 * that some requests will fail.
205 * If we were able to get the show for at least one
206 * attach type, let's return 0.
207 */
208 if (show_attached_bpf_progs(cgroup_fd, type, 0) == 0)
209 ret = 0;
210 }
211
212 if (json_output)
213 jsonw_end_array(json_wtr);
214
215 close(cgroup_fd);
216exit:
217 return ret;
218}
219
220/*
221 * To distinguish nftw() errors and do_show_tree_fn() errors
222 * and avoid duplicating error messages, let's return -2
223 * from do_show_tree_fn() in case of error.
224 */
225#define NFTW_ERR -1
226#define SHOW_TREE_FN_ERR -2
227static int do_show_tree_fn(const char *fpath, const struct stat *sb,
228 int typeflag, struct FTW *ftw)
229{
230 enum bpf_attach_type type;
231 bool skip = true;
232 int cgroup_fd;
233
234 if (typeflag != FTW_D)
235 return 0;
236
237 cgroup_fd = open(fpath, O_RDONLY);
238 if (cgroup_fd < 0) {
239 p_err("can't open cgroup %s: %s", fpath, strerror(errno));
240 return SHOW_TREE_FN_ERR;
241 }
242
243 for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
244 int count = count_attached_bpf_progs(cgroup_fd, type);
245
246 if (count < 0 && errno != EINVAL) {
247 p_err("can't query bpf programs attached to %s: %s",
248 fpath, strerror(errno));
249 close(cgroup_fd);
250 return SHOW_TREE_FN_ERR;
251 }
252 if (count > 0) {
253 skip = false;
254 break;
255 }
256 }
257
258 if (skip) {
259 close(cgroup_fd);
260 return 0;
261 }
262
263 if (json_output) {
264 jsonw_start_object(json_wtr);
265 jsonw_string_field(json_wtr, "cgroup", fpath);
266 jsonw_name(json_wtr, "programs");
267 jsonw_start_array(json_wtr);
268 } else {
269 printf("%s\n", fpath);
270 }
271
272 for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++)
273 show_attached_bpf_progs(cgroup_fd, type, ftw->level);
274
275 if (errno == EINVAL)
276 /* Last attach type does not support query.
277 * Do not report an error for this, especially because batch
278 * mode would stop processing commands.
279 */
280 errno = 0;
281
282 if (json_output) {
283 jsonw_end_array(json_wtr);
284 jsonw_end_object(json_wtr);
285 }
286
287 close(cgroup_fd);
288
289 return 0;
290}
291
292static char *find_cgroup_root(void)
293{
294 struct mntent *mnt;
295 FILE *f;
296
297 f = fopen("/proc/mounts", "r");
298 if (f == NULL)
299 return NULL;
300
301 while ((mnt = getmntent(f))) {
302 if (strcmp(mnt->mnt_type, "cgroup2") == 0) {
303 fclose(f);
304 return strdup(mnt->mnt_dir);
305 }
306 }
307
308 fclose(f);
309 return NULL;
310}
311
312static int do_show_tree(int argc, char **argv)
313{
314 char *cgroup_root, *cgroup_alloced = NULL;
315 int ret;
316
317 query_flags = 0;
318
319 if (!argc) {
320 cgroup_alloced = find_cgroup_root();
321 if (!cgroup_alloced) {
322 p_err("cgroup v2 isn't mounted");
323 return -1;
324 }
325 cgroup_root = cgroup_alloced;
326 } else {
327 cgroup_root = GET_ARG();
328
329 while (argc) {
330 if (is_prefix(*argv, "effective")) {
331 if (query_flags & BPF_F_QUERY_EFFECTIVE) {
332 p_err("duplicated argument: %s", *argv);
333 return -1;
334 }
335 query_flags |= BPF_F_QUERY_EFFECTIVE;
336 NEXT_ARG();
337 } else {
338 p_err("expected no more arguments, 'effective', got: '%s'?",
339 *argv);
340 return -1;
341 }
342 }
343 }
344
345 if (json_output)
346 jsonw_start_array(json_wtr);
347 else
348 printf("%s\n"
349 "%-8s %-15s %-15s %-15s\n",
350 "CgroupPath",
351 "ID", "AttachType", "AttachFlags", "Name");
352
353 switch (nftw(cgroup_root, do_show_tree_fn, 1024, FTW_MOUNT)) {
354 case NFTW_ERR:
355 p_err("can't iterate over %s: %s", cgroup_root,
356 strerror(errno));
357 ret = -1;
358 break;
359 case SHOW_TREE_FN_ERR:
360 ret = -1;
361 break;
362 default:
363 ret = 0;
364 }
365
366 if (json_output)
367 jsonw_end_array(json_wtr);
368
369 free(cgroup_alloced);
370
371 return ret;
372}
373
374static int do_attach(int argc, char **argv)
375{
376 enum bpf_attach_type attach_type;
377 int cgroup_fd, prog_fd;
378 int attach_flags = 0;
379 int ret = -1;
380 int i;
381
382 if (argc < 4) {
383 p_err("too few parameters for cgroup attach");
384 goto exit;
385 }
386
387 cgroup_fd = open(argv[0], O_RDONLY);
388 if (cgroup_fd < 0) {
389 p_err("can't open cgroup %s", argv[0]);
390 goto exit;
391 }
392
393 attach_type = parse_attach_type(argv[1]);
394 if (attach_type == __MAX_BPF_ATTACH_TYPE) {
395 p_err("invalid attach type");
396 goto exit_cgroup;
397 }
398
399 argc -= 2;
400 argv = &argv[2];
401 prog_fd = prog_parse_fd(&argc, &argv);
402 if (prog_fd < 0)
403 goto exit_cgroup;
404
405 for (i = 0; i < argc; i++) {
406 if (is_prefix(argv[i], "multi")) {
407 attach_flags |= BPF_F_ALLOW_MULTI;
408 } else if (is_prefix(argv[i], "override")) {
409 attach_flags |= BPF_F_ALLOW_OVERRIDE;
410 } else {
411 p_err("unknown option: %s", argv[i]);
412 goto exit_cgroup;
413 }
414 }
415
416 if (bpf_prog_attach(prog_fd, cgroup_fd, attach_type, attach_flags)) {
417 p_err("failed to attach program");
418 goto exit_prog;
419 }
420
421 if (json_output)
422 jsonw_null(json_wtr);
423
424 ret = 0;
425
426exit_prog:
427 close(prog_fd);
428exit_cgroup:
429 close(cgroup_fd);
430exit:
431 return ret;
432}
433
434static int do_detach(int argc, char **argv)
435{
436 enum bpf_attach_type attach_type;
437 int prog_fd, cgroup_fd;
438 int ret = -1;
439
440 if (argc < 4) {
441 p_err("too few parameters for cgroup detach");
442 goto exit;
443 }
444
445 cgroup_fd = open(argv[0], O_RDONLY);
446 if (cgroup_fd < 0) {
447 p_err("can't open cgroup %s", argv[0]);
448 goto exit;
449 }
450
451 attach_type = parse_attach_type(argv[1]);
452 if (attach_type == __MAX_BPF_ATTACH_TYPE) {
453 p_err("invalid attach type");
454 goto exit_cgroup;
455 }
456
457 argc -= 2;
458 argv = &argv[2];
459 prog_fd = prog_parse_fd(&argc, &argv);
460 if (prog_fd < 0)
461 goto exit_cgroup;
462
463 if (bpf_prog_detach2(prog_fd, cgroup_fd, attach_type)) {
464 p_err("failed to detach program");
465 goto exit_prog;
466 }
467
468 if (json_output)
469 jsonw_null(json_wtr);
470
471 ret = 0;
472
473exit_prog:
474 close(prog_fd);
475exit_cgroup:
476 close(cgroup_fd);
477exit:
478 return ret;
479}
480
481static int do_help(int argc, char **argv)
482{
483 if (json_output) {
484 jsonw_null(json_wtr);
485 return 0;
486 }
487
488 fprintf(stderr,
489 "Usage: %s %s { show | list } CGROUP [**effective**]\n"
490 " %s %s tree [CGROUP_ROOT] [**effective**]\n"
491 " %s %s attach CGROUP ATTACH_TYPE PROG [ATTACH_FLAGS]\n"
492 " %s %s detach CGROUP ATTACH_TYPE PROG\n"
493 " %s %s help\n"
494 "\n"
495 HELP_SPEC_ATTACH_TYPES "\n"
496 " " HELP_SPEC_ATTACH_FLAGS "\n"
497 " " HELP_SPEC_PROGRAM "\n"
498 " " HELP_SPEC_OPTIONS "\n"
499 "",
500 bin_name, argv[-2],
501 bin_name, argv[-2], bin_name, argv[-2],
502 bin_name, argv[-2], bin_name, argv[-2]);
503
504 return 0;
505}
506
507static const struct cmd cmds[] = {
508 { "show", do_show },
509 { "list", do_show },
510 { "tree", do_show_tree },
511 { "attach", do_attach },
512 { "detach", do_detach },
513 { "help", do_help },
514 { 0 }
515};
516
517int do_cgroup(int argc, char **argv)
518{
519 return cmd_select(cmds, argc, argv, do_help);
520}