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/bpf.h>
18 #include <bpf/btf.h>
19
20 #include "main.h"
21
22 #define HELP_SPEC_ATTACH_FLAGS \
23 "ATTACH_FLAGS := { multi | override }"
24
25 #define HELP_SPEC_ATTACH_TYPES \
26 " ATTACH_TYPE := { cgroup_inet_ingress | cgroup_inet_egress |\n" \
27 " cgroup_inet_sock_create | cgroup_sock_ops |\n" \
28 " cgroup_device | cgroup_inet4_bind |\n" \
29 " cgroup_inet6_bind | cgroup_inet4_post_bind |\n" \
30 " cgroup_inet6_post_bind | cgroup_inet4_connect |\n" \
31 " cgroup_inet6_connect | cgroup_inet4_getpeername |\n" \
32 " cgroup_inet6_getpeername | cgroup_inet4_getsockname |\n" \
33 " cgroup_inet6_getsockname | cgroup_udp4_sendmsg |\n" \
34 " cgroup_udp6_sendmsg | cgroup_udp4_recvmsg |\n" \
35 " cgroup_udp6_recvmsg | cgroup_sysctl |\n" \
36 " cgroup_getsockopt | cgroup_setsockopt |\n" \
37 " cgroup_inet_sock_release }"
38
39 static unsigned int query_flags;
40 static struct btf *btf_vmlinux;
41 static __u32 btf_vmlinux_id;
42
parse_attach_type(const char * str)43 static enum bpf_attach_type parse_attach_type(const char *str)
44 {
45 const char *attach_type_str;
46 enum bpf_attach_type type;
47
48 for (type = 0; ; type++) {
49 attach_type_str = libbpf_bpf_attach_type_str(type);
50 if (!attach_type_str)
51 break;
52 if (!strcmp(str, attach_type_str))
53 return type;
54 }
55
56 /* Also check traditionally used attach type strings. For these we keep
57 * allowing prefixed usage.
58 */
59 for (type = 0; ; type++) {
60 attach_type_str = bpf_attach_type_input_str(type);
61 if (!attach_type_str)
62 break;
63 if (is_prefix(str, attach_type_str))
64 return type;
65 }
66
67 return __MAX_BPF_ATTACH_TYPE;
68 }
69
guess_vmlinux_btf_id(__u32 attach_btf_obj_id)70 static void guess_vmlinux_btf_id(__u32 attach_btf_obj_id)
71 {
72 struct bpf_btf_info btf_info = {};
73 __u32 btf_len = sizeof(btf_info);
74 char name[16] = {};
75 int err;
76 int fd;
77
78 btf_info.name = ptr_to_u64(name);
79 btf_info.name_len = sizeof(name);
80
81 fd = bpf_btf_get_fd_by_id(attach_btf_obj_id);
82 if (fd < 0)
83 return;
84
85 err = bpf_obj_get_info_by_fd(fd, &btf_info, &btf_len);
86 if (err)
87 goto out;
88
89 if (btf_info.kernel_btf && strncmp(name, "vmlinux", sizeof(name)) == 0)
90 btf_vmlinux_id = btf_info.id;
91
92 out:
93 close(fd);
94 }
95
show_bpf_prog(int id,enum bpf_attach_type attach_type,const char * attach_flags_str,int level)96 static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
97 const char *attach_flags_str,
98 int level)
99 {
100 char prog_name[MAX_PROG_FULL_NAME];
101 const char *attach_btf_name = NULL;
102 struct bpf_prog_info info = {};
103 const char *attach_type_str;
104 __u32 info_len = sizeof(info);
105 int prog_fd;
106
107 prog_fd = bpf_prog_get_fd_by_id(id);
108 if (prog_fd < 0)
109 return -1;
110
111 if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) {
112 close(prog_fd);
113 return -1;
114 }
115
116 attach_type_str = libbpf_bpf_attach_type_str(attach_type);
117
118 if (btf_vmlinux) {
119 if (!btf_vmlinux_id)
120 guess_vmlinux_btf_id(info.attach_btf_obj_id);
121
122 if (btf_vmlinux_id == info.attach_btf_obj_id &&
123 info.attach_btf_id < btf__type_cnt(btf_vmlinux)) {
124 const struct btf_type *t =
125 btf__type_by_id(btf_vmlinux, info.attach_btf_id);
126 attach_btf_name =
127 btf__name_by_offset(btf_vmlinux, t->name_off);
128 }
129 }
130
131 get_prog_full_name(&info, prog_fd, prog_name, sizeof(prog_name));
132 if (json_output) {
133 jsonw_start_object(json_wtr);
134 jsonw_uint_field(json_wtr, "id", info.id);
135 if (attach_type_str)
136 jsonw_string_field(json_wtr, "attach_type", attach_type_str);
137 else
138 jsonw_uint_field(json_wtr, "attach_type", attach_type);
139 if (!(query_flags & BPF_F_QUERY_EFFECTIVE))
140 jsonw_string_field(json_wtr, "attach_flags", attach_flags_str);
141 jsonw_string_field(json_wtr, "name", prog_name);
142 if (attach_btf_name)
143 jsonw_string_field(json_wtr, "attach_btf_name", attach_btf_name);
144 jsonw_uint_field(json_wtr, "attach_btf_obj_id", info.attach_btf_obj_id);
145 jsonw_uint_field(json_wtr, "attach_btf_id", info.attach_btf_id);
146 jsonw_end_object(json_wtr);
147 } else {
148 printf("%s%-8u ", level ? " " : "", info.id);
149 if (attach_type_str)
150 printf("%-15s", attach_type_str);
151 else
152 printf("type %-10u", attach_type);
153 if (query_flags & BPF_F_QUERY_EFFECTIVE)
154 printf(" %-15s", prog_name);
155 else
156 printf(" %-15s %-15s", attach_flags_str, prog_name);
157 if (attach_btf_name)
158 printf(" %-15s", attach_btf_name);
159 else if (info.attach_btf_id)
160 printf(" attach_btf_obj_id=%d attach_btf_id=%d",
161 info.attach_btf_obj_id, info.attach_btf_id);
162 printf("\n");
163 }
164
165 close(prog_fd);
166 return 0;
167 }
168
count_attached_bpf_progs(int cgroup_fd,enum bpf_attach_type type)169 static int count_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
170 {
171 __u32 prog_cnt = 0;
172 int ret;
173
174 ret = bpf_prog_query(cgroup_fd, type, query_flags, NULL,
175 NULL, &prog_cnt);
176 if (ret)
177 return -1;
178
179 return prog_cnt;
180 }
181
cgroup_has_attached_progs(int cgroup_fd)182 static int cgroup_has_attached_progs(int cgroup_fd)
183 {
184 enum bpf_attach_type type;
185 bool no_prog = true;
186
187 for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
188 int count = count_attached_bpf_progs(cgroup_fd, type);
189
190 if (count < 0 && errno != EINVAL)
191 return -1;
192
193 if (count > 0) {
194 no_prog = false;
195 break;
196 }
197 }
198
199 return no_prog ? 0 : 1;
200 }
201
show_effective_bpf_progs(int cgroup_fd,enum bpf_attach_type type,int level)202 static int show_effective_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
203 int level)
204 {
205 LIBBPF_OPTS(bpf_prog_query_opts, p);
206 __u32 prog_ids[1024] = {0};
207 __u32 iter;
208 int ret;
209
210 p.query_flags = query_flags;
211 p.prog_cnt = ARRAY_SIZE(prog_ids);
212 p.prog_ids = prog_ids;
213
214 ret = bpf_prog_query_opts(cgroup_fd, type, &p);
215 if (ret)
216 return ret;
217
218 if (p.prog_cnt == 0)
219 return 0;
220
221 for (iter = 0; iter < p.prog_cnt; iter++)
222 show_bpf_prog(prog_ids[iter], type, NULL, level);
223
224 return 0;
225 }
226
show_attached_bpf_progs(int cgroup_fd,enum bpf_attach_type type,int level)227 static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
228 int level)
229 {
230 LIBBPF_OPTS(bpf_prog_query_opts, p);
231 __u32 prog_attach_flags[1024] = {0};
232 const char *attach_flags_str;
233 __u32 prog_ids[1024] = {0};
234 char buf[32];
235 __u32 iter;
236 int ret;
237
238 p.query_flags = query_flags;
239 p.prog_cnt = ARRAY_SIZE(prog_ids);
240 p.prog_ids = prog_ids;
241 p.prog_attach_flags = prog_attach_flags;
242
243 ret = bpf_prog_query_opts(cgroup_fd, type, &p);
244 if (ret)
245 return ret;
246
247 if (p.prog_cnt == 0)
248 return 0;
249
250 for (iter = 0; iter < p.prog_cnt; iter++) {
251 __u32 attach_flags;
252
253 attach_flags = prog_attach_flags[iter] ?: p.attach_flags;
254
255 switch (attach_flags) {
256 case BPF_F_ALLOW_MULTI:
257 attach_flags_str = "multi";
258 break;
259 case BPF_F_ALLOW_OVERRIDE:
260 attach_flags_str = "override";
261 break;
262 case 0:
263 attach_flags_str = "";
264 break;
265 default:
266 snprintf(buf, sizeof(buf), "unknown(%x)", attach_flags);
267 attach_flags_str = buf;
268 }
269
270 show_bpf_prog(prog_ids[iter], type,
271 attach_flags_str, level);
272 }
273
274 return 0;
275 }
276
show_bpf_progs(int cgroup_fd,enum bpf_attach_type type,int level)277 static int show_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
278 int level)
279 {
280 return query_flags & BPF_F_QUERY_EFFECTIVE ?
281 show_effective_bpf_progs(cgroup_fd, type, level) :
282 show_attached_bpf_progs(cgroup_fd, type, level);
283 }
284
do_show(int argc,char ** argv)285 static int do_show(int argc, char **argv)
286 {
287 enum bpf_attach_type type;
288 int has_attached_progs;
289 const char *path;
290 int cgroup_fd;
291 int ret = -1;
292
293 query_flags = 0;
294
295 if (!REQ_ARGS(1))
296 return -1;
297 path = GET_ARG();
298
299 while (argc) {
300 if (is_prefix(*argv, "effective")) {
301 if (query_flags & BPF_F_QUERY_EFFECTIVE) {
302 p_err("duplicated argument: %s", *argv);
303 return -1;
304 }
305 query_flags |= BPF_F_QUERY_EFFECTIVE;
306 NEXT_ARG();
307 } else {
308 p_err("expected no more arguments, 'effective', got: '%s'?",
309 *argv);
310 return -1;
311 }
312 }
313
314 cgroup_fd = open(path, O_RDONLY);
315 if (cgroup_fd < 0) {
316 p_err("can't open cgroup %s", path);
317 goto exit;
318 }
319
320 has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
321 if (has_attached_progs < 0) {
322 p_err("can't query bpf programs attached to %s: %s",
323 path, strerror(errno));
324 goto exit_cgroup;
325 } else if (!has_attached_progs) {
326 ret = 0;
327 goto exit_cgroup;
328 }
329
330 if (json_output)
331 jsonw_start_array(json_wtr);
332 else if (query_flags & BPF_F_QUERY_EFFECTIVE)
333 printf("%-8s %-15s %-15s\n", "ID", "AttachType", "Name");
334 else
335 printf("%-8s %-15s %-15s %-15s\n", "ID", "AttachType",
336 "AttachFlags", "Name");
337
338 btf_vmlinux = libbpf_find_kernel_btf();
339 for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
340 /*
341 * Not all attach types may be supported, so it's expected,
342 * that some requests will fail.
343 * If we were able to get the show for at least one
344 * attach type, let's return 0.
345 */
346 if (show_bpf_progs(cgroup_fd, type, 0) == 0)
347 ret = 0;
348 }
349
350 if (json_output)
351 jsonw_end_array(json_wtr);
352
353 exit_cgroup:
354 close(cgroup_fd);
355 exit:
356 return ret;
357 }
358
359 /*
360 * To distinguish nftw() errors and do_show_tree_fn() errors
361 * and avoid duplicating error messages, let's return -2
362 * from do_show_tree_fn() in case of error.
363 */
364 #define NFTW_ERR -1
365 #define SHOW_TREE_FN_ERR -2
do_show_tree_fn(const char * fpath,const struct stat * sb,int typeflag,struct FTW * ftw)366 static int do_show_tree_fn(const char *fpath, const struct stat *sb,
367 int typeflag, struct FTW *ftw)
368 {
369 enum bpf_attach_type type;
370 int has_attached_progs;
371 int cgroup_fd;
372
373 if (typeflag != FTW_D)
374 return 0;
375
376 cgroup_fd = open(fpath, O_RDONLY);
377 if (cgroup_fd < 0) {
378 p_err("can't open cgroup %s: %s", fpath, strerror(errno));
379 return SHOW_TREE_FN_ERR;
380 }
381
382 has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
383 if (has_attached_progs < 0) {
384 p_err("can't query bpf programs attached to %s: %s",
385 fpath, strerror(errno));
386 close(cgroup_fd);
387 return SHOW_TREE_FN_ERR;
388 } else if (!has_attached_progs) {
389 close(cgroup_fd);
390 return 0;
391 }
392
393 if (json_output) {
394 jsonw_start_object(json_wtr);
395 jsonw_string_field(json_wtr, "cgroup", fpath);
396 jsonw_name(json_wtr, "programs");
397 jsonw_start_array(json_wtr);
398 } else {
399 printf("%s\n", fpath);
400 }
401
402 btf_vmlinux = libbpf_find_kernel_btf();
403 for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++)
404 show_bpf_progs(cgroup_fd, type, ftw->level);
405
406 if (errno == EINVAL)
407 /* Last attach type does not support query.
408 * Do not report an error for this, especially because batch
409 * mode would stop processing commands.
410 */
411 errno = 0;
412
413 if (json_output) {
414 jsonw_end_array(json_wtr);
415 jsonw_end_object(json_wtr);
416 }
417
418 close(cgroup_fd);
419
420 return 0;
421 }
422
find_cgroup_root(void)423 static char *find_cgroup_root(void)
424 {
425 struct mntent *mnt;
426 FILE *f;
427
428 f = fopen("/proc/mounts", "r");
429 if (f == NULL)
430 return NULL;
431
432 while ((mnt = getmntent(f))) {
433 if (strcmp(mnt->mnt_type, "cgroup2") == 0) {
434 fclose(f);
435 return strdup(mnt->mnt_dir);
436 }
437 }
438
439 fclose(f);
440 return NULL;
441 }
442
do_show_tree(int argc,char ** argv)443 static int do_show_tree(int argc, char **argv)
444 {
445 char *cgroup_root, *cgroup_alloced = NULL;
446 int ret;
447
448 query_flags = 0;
449
450 if (!argc) {
451 cgroup_alloced = find_cgroup_root();
452 if (!cgroup_alloced) {
453 p_err("cgroup v2 isn't mounted");
454 return -1;
455 }
456 cgroup_root = cgroup_alloced;
457 } else {
458 cgroup_root = GET_ARG();
459
460 while (argc) {
461 if (is_prefix(*argv, "effective")) {
462 if (query_flags & BPF_F_QUERY_EFFECTIVE) {
463 p_err("duplicated argument: %s", *argv);
464 return -1;
465 }
466 query_flags |= BPF_F_QUERY_EFFECTIVE;
467 NEXT_ARG();
468 } else {
469 p_err("expected no more arguments, 'effective', got: '%s'?",
470 *argv);
471 return -1;
472 }
473 }
474 }
475
476 if (json_output)
477 jsonw_start_array(json_wtr);
478 else if (query_flags & BPF_F_QUERY_EFFECTIVE)
479 printf("%s\n"
480 "%-8s %-15s %-15s\n",
481 "CgroupPath",
482 "ID", "AttachType", "Name");
483 else
484 printf("%s\n"
485 "%-8s %-15s %-15s %-15s\n",
486 "CgroupPath",
487 "ID", "AttachType", "AttachFlags", "Name");
488
489 switch (nftw(cgroup_root, do_show_tree_fn, 1024, FTW_MOUNT)) {
490 case NFTW_ERR:
491 p_err("can't iterate over %s: %s", cgroup_root,
492 strerror(errno));
493 ret = -1;
494 break;
495 case SHOW_TREE_FN_ERR:
496 ret = -1;
497 break;
498 default:
499 ret = 0;
500 }
501
502 if (json_output)
503 jsonw_end_array(json_wtr);
504
505 free(cgroup_alloced);
506
507 return ret;
508 }
509
do_attach(int argc,char ** argv)510 static int do_attach(int argc, char **argv)
511 {
512 enum bpf_attach_type attach_type;
513 int cgroup_fd, prog_fd;
514 int attach_flags = 0;
515 int ret = -1;
516 int i;
517
518 if (argc < 4) {
519 p_err("too few parameters for cgroup attach");
520 goto exit;
521 }
522
523 cgroup_fd = open(argv[0], O_RDONLY);
524 if (cgroup_fd < 0) {
525 p_err("can't open cgroup %s", argv[0]);
526 goto exit;
527 }
528
529 attach_type = parse_attach_type(argv[1]);
530 if (attach_type == __MAX_BPF_ATTACH_TYPE) {
531 p_err("invalid attach type");
532 goto exit_cgroup;
533 }
534
535 argc -= 2;
536 argv = &argv[2];
537 prog_fd = prog_parse_fd(&argc, &argv);
538 if (prog_fd < 0)
539 goto exit_cgroup;
540
541 for (i = 0; i < argc; i++) {
542 if (is_prefix(argv[i], "multi")) {
543 attach_flags |= BPF_F_ALLOW_MULTI;
544 } else if (is_prefix(argv[i], "override")) {
545 attach_flags |= BPF_F_ALLOW_OVERRIDE;
546 } else {
547 p_err("unknown option: %s", argv[i]);
548 goto exit_cgroup;
549 }
550 }
551
552 if (bpf_prog_attach(prog_fd, cgroup_fd, attach_type, attach_flags)) {
553 p_err("failed to attach program");
554 goto exit_prog;
555 }
556
557 if (json_output)
558 jsonw_null(json_wtr);
559
560 ret = 0;
561
562 exit_prog:
563 close(prog_fd);
564 exit_cgroup:
565 close(cgroup_fd);
566 exit:
567 return ret;
568 }
569
do_detach(int argc,char ** argv)570 static int do_detach(int argc, char **argv)
571 {
572 enum bpf_attach_type attach_type;
573 int prog_fd, cgroup_fd;
574 int ret = -1;
575
576 if (argc < 4) {
577 p_err("too few parameters for cgroup detach");
578 goto exit;
579 }
580
581 cgroup_fd = open(argv[0], O_RDONLY);
582 if (cgroup_fd < 0) {
583 p_err("can't open cgroup %s", argv[0]);
584 goto exit;
585 }
586
587 attach_type = parse_attach_type(argv[1]);
588 if (attach_type == __MAX_BPF_ATTACH_TYPE) {
589 p_err("invalid attach type");
590 goto exit_cgroup;
591 }
592
593 argc -= 2;
594 argv = &argv[2];
595 prog_fd = prog_parse_fd(&argc, &argv);
596 if (prog_fd < 0)
597 goto exit_cgroup;
598
599 if (bpf_prog_detach2(prog_fd, cgroup_fd, attach_type)) {
600 p_err("failed to detach program");
601 goto exit_prog;
602 }
603
604 if (json_output)
605 jsonw_null(json_wtr);
606
607 ret = 0;
608
609 exit_prog:
610 close(prog_fd);
611 exit_cgroup:
612 close(cgroup_fd);
613 exit:
614 return ret;
615 }
616
do_help(int argc,char ** argv)617 static int do_help(int argc, char **argv)
618 {
619 if (json_output) {
620 jsonw_null(json_wtr);
621 return 0;
622 }
623
624 fprintf(stderr,
625 "Usage: %1$s %2$s { show | list } CGROUP [**effective**]\n"
626 " %1$s %2$s tree [CGROUP_ROOT] [**effective**]\n"
627 " %1$s %2$s attach CGROUP ATTACH_TYPE PROG [ATTACH_FLAGS]\n"
628 " %1$s %2$s detach CGROUP ATTACH_TYPE PROG\n"
629 " %1$s %2$s help\n"
630 "\n"
631 HELP_SPEC_ATTACH_TYPES "\n"
632 " " HELP_SPEC_ATTACH_FLAGS "\n"
633 " " HELP_SPEC_PROGRAM "\n"
634 " " HELP_SPEC_OPTIONS " |\n"
635 " {-f|--bpffs} }\n"
636 "",
637 bin_name, argv[-2]);
638
639 return 0;
640 }
641
642 static const struct cmd cmds[] = {
643 { "show", do_show },
644 { "list", do_show },
645 { "tree", do_show_tree },
646 { "attach", do_attach },
647 { "detach", do_detach },
648 { "help", do_help },
649 { 0 }
650 };
651
do_cgroup(int argc,char ** argv)652 int do_cgroup(int argc, char **argv)
653 {
654 return cmd_select(cmds, argc, argv, do_help);
655 }
656