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v5.14.15
  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
 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 | getpeername4 | getpeername6 |\n"   \
 29	"                        getsockname4 | getsockname6 | sendmsg4 |\n"   \
 30	"                        sendmsg6 | recvmsg4 | recvmsg6 |\n"           \
 31	"                        sysctl | getsockopt | setsockopt |\n"	       \
 32	"                        sock_release }"
 33
 34static unsigned int query_flags;
 35
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 36static enum bpf_attach_type parse_attach_type(const char *str)
 37{
 38	enum bpf_attach_type type;
 39
 40	for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
 41		if (attach_type_name[type] &&
 42		    is_prefix(str, attach_type_name[type]))
 43			return type;
 44	}
 45
 46	return __MAX_BPF_ATTACH_TYPE;
 47}
 48
 49static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
 50			 const char *attach_flags_str,
 51			 int level)
 52{
 53	struct bpf_prog_info info = {};
 54	__u32 info_len = sizeof(info);
 55	int prog_fd;
 56
 57	prog_fd = bpf_prog_get_fd_by_id(id);
 58	if (prog_fd < 0)
 59		return -1;
 60
 61	if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) {
 62		close(prog_fd);
 63		return -1;
 64	}
 65
 66	if (json_output) {
 67		jsonw_start_object(json_wtr);
 68		jsonw_uint_field(json_wtr, "id", info.id);
 69		if (attach_type < ARRAY_SIZE(attach_type_name))
 70			jsonw_string_field(json_wtr, "attach_type",
 71					   attach_type_name[attach_type]);
 72		else
 73			jsonw_uint_field(json_wtr, "attach_type", attach_type);
 74		jsonw_string_field(json_wtr, "attach_flags",
 75				   attach_flags_str);
 76		jsonw_string_field(json_wtr, "name", info.name);
 77		jsonw_end_object(json_wtr);
 78	} else {
 79		printf("%s%-8u ", level ? "    " : "", info.id);
 80		if (attach_type < ARRAY_SIZE(attach_type_name))
 81			printf("%-15s", attach_type_name[attach_type]);
 82		else
 83			printf("type %-10u", attach_type);
 84		printf(" %-15s %-15s\n", attach_flags_str, info.name);
 85	}
 86
 87	close(prog_fd);
 88	return 0;
 89}
 90
 91static int count_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
 92{
 93	__u32 prog_cnt = 0;
 94	int ret;
 95
 96	ret = bpf_prog_query(cgroup_fd, type, query_flags, NULL,
 97			     NULL, &prog_cnt);
 98	if (ret)
 99		return -1;
100
101	return prog_cnt;
102}
103
104static int cgroup_has_attached_progs(int cgroup_fd)
105{
106	enum bpf_attach_type type;
107	bool no_prog = true;
108
109	for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
110		int count = count_attached_bpf_progs(cgroup_fd, type);
111
112		if (count < 0 && errno != EINVAL)
113			return -1;
114
115		if (count > 0) {
116			no_prog = false;
117			break;
118		}
119	}
120
121	return no_prog ? 0 : 1;
122}
123static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
124				   int level)
125{
126	const char *attach_flags_str;
127	__u32 prog_ids[1024] = {0};
128	__u32 prog_cnt, iter;
129	__u32 attach_flags;
130	char buf[32];
131	int ret;
132
133	prog_cnt = ARRAY_SIZE(prog_ids);
134	ret = bpf_prog_query(cgroup_fd, type, query_flags, &attach_flags,
135			     prog_ids, &prog_cnt);
136	if (ret)
137		return ret;
138
139	if (prog_cnt == 0)
140		return 0;
141
142	switch (attach_flags) {
143	case BPF_F_ALLOW_MULTI:
144		attach_flags_str = "multi";
145		break;
146	case BPF_F_ALLOW_OVERRIDE:
147		attach_flags_str = "override";
148		break;
149	case 0:
150		attach_flags_str = "";
151		break;
152	default:
153		snprintf(buf, sizeof(buf), "unknown(%x)", attach_flags);
154		attach_flags_str = buf;
155	}
156
157	for (iter = 0; iter < prog_cnt; iter++)
158		show_bpf_prog(prog_ids[iter], type,
159			      attach_flags_str, level);
160
161	return 0;
162}
163
164static int do_show(int argc, char **argv)
165{
166	enum bpf_attach_type type;
167	int has_attached_progs;
168	const char *path;
169	int cgroup_fd;
170	int ret = -1;
171
172	query_flags = 0;
173
174	if (!REQ_ARGS(1))
175		return -1;
176	path = GET_ARG();
177
178	while (argc) {
179		if (is_prefix(*argv, "effective")) {
180			if (query_flags & BPF_F_QUERY_EFFECTIVE) {
181				p_err("duplicated argument: %s", *argv);
182				return -1;
183			}
184			query_flags |= BPF_F_QUERY_EFFECTIVE;
185			NEXT_ARG();
186		} else {
187			p_err("expected no more arguments, 'effective', got: '%s'?",
188			      *argv);
189			return -1;
190		}
191	}
192
193	cgroup_fd = open(path, O_RDONLY);
194	if (cgroup_fd < 0) {
195		p_err("can't open cgroup %s", path);
196		goto exit;
197	}
198
199	has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
200	if (has_attached_progs < 0) {
201		p_err("can't query bpf programs attached to %s: %s",
202		      path, strerror(errno));
203		goto exit_cgroup;
204	} else if (!has_attached_progs) {
205		ret = 0;
206		goto exit_cgroup;
207	}
208
209	if (json_output)
210		jsonw_start_array(json_wtr);
211	else
212		printf("%-8s %-15s %-15s %-15s\n", "ID", "AttachType",
213		       "AttachFlags", "Name");
214
215	for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
216		/*
217		 * Not all attach types may be supported, so it's expected,
218		 * that some requests will fail.
219		 * If we were able to get the show for at least one
220		 * attach type, let's return 0.
221		 */
222		if (show_attached_bpf_progs(cgroup_fd, type, 0) == 0)
223			ret = 0;
224	}
225
226	if (json_output)
227		jsonw_end_array(json_wtr);
228
229exit_cgroup:
230	close(cgroup_fd);
231exit:
232	return ret;
233}
234
235/*
236 * To distinguish nftw() errors and do_show_tree_fn() errors
237 * and avoid duplicating error messages, let's return -2
238 * from do_show_tree_fn() in case of error.
239 */
240#define NFTW_ERR		-1
241#define SHOW_TREE_FN_ERR	-2
242static int do_show_tree_fn(const char *fpath, const struct stat *sb,
243			   int typeflag, struct FTW *ftw)
244{
245	enum bpf_attach_type type;
246	int has_attached_progs;
247	int cgroup_fd;
248
249	if (typeflag != FTW_D)
250		return 0;
251
252	cgroup_fd = open(fpath, O_RDONLY);
253	if (cgroup_fd < 0) {
254		p_err("can't open cgroup %s: %s", fpath, strerror(errno));
255		return SHOW_TREE_FN_ERR;
256	}
257
258	has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
259	if (has_attached_progs < 0) {
260		p_err("can't query bpf programs attached to %s: %s",
261		      fpath, strerror(errno));
262		close(cgroup_fd);
263		return SHOW_TREE_FN_ERR;
264	} else if (!has_attached_progs) {
 
 
 
 
 
 
 
 
 
265		close(cgroup_fd);
266		return 0;
267	}
268
269	if (json_output) {
270		jsonw_start_object(json_wtr);
271		jsonw_string_field(json_wtr, "cgroup", fpath);
272		jsonw_name(json_wtr, "programs");
273		jsonw_start_array(json_wtr);
274	} else {
275		printf("%s\n", fpath);
276	}
277
278	for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++)
279		show_attached_bpf_progs(cgroup_fd, type, ftw->level);
280
281	if (errno == EINVAL)
282		/* Last attach type does not support query.
283		 * Do not report an error for this, especially because batch
284		 * mode would stop processing commands.
285		 */
286		errno = 0;
287
288	if (json_output) {
289		jsonw_end_array(json_wtr);
290		jsonw_end_object(json_wtr);
291	}
292
293	close(cgroup_fd);
294
295	return 0;
296}
297
298static char *find_cgroup_root(void)
299{
300	struct mntent *mnt;
301	FILE *f;
302
303	f = fopen("/proc/mounts", "r");
304	if (f == NULL)
305		return NULL;
306
307	while ((mnt = getmntent(f))) {
308		if (strcmp(mnt->mnt_type, "cgroup2") == 0) {
309			fclose(f);
310			return strdup(mnt->mnt_dir);
311		}
312	}
313
314	fclose(f);
315	return NULL;
316}
317
318static int do_show_tree(int argc, char **argv)
319{
320	char *cgroup_root, *cgroup_alloced = NULL;
321	int ret;
322
323	query_flags = 0;
324
325	if (!argc) {
326		cgroup_alloced = find_cgroup_root();
327		if (!cgroup_alloced) {
328			p_err("cgroup v2 isn't mounted");
329			return -1;
330		}
331		cgroup_root = cgroup_alloced;
332	} else {
333		cgroup_root = GET_ARG();
334
335		while (argc) {
336			if (is_prefix(*argv, "effective")) {
337				if (query_flags & BPF_F_QUERY_EFFECTIVE) {
338					p_err("duplicated argument: %s", *argv);
339					return -1;
340				}
341				query_flags |= BPF_F_QUERY_EFFECTIVE;
342				NEXT_ARG();
343			} else {
344				p_err("expected no more arguments, 'effective', got: '%s'?",
345				      *argv);
346				return -1;
347			}
348		}
349	}
350
351	if (json_output)
352		jsonw_start_array(json_wtr);
353	else
354		printf("%s\n"
355		       "%-8s %-15s %-15s %-15s\n",
356		       "CgroupPath",
357		       "ID", "AttachType", "AttachFlags", "Name");
358
359	switch (nftw(cgroup_root, do_show_tree_fn, 1024, FTW_MOUNT)) {
360	case NFTW_ERR:
361		p_err("can't iterate over %s: %s", cgroup_root,
362		      strerror(errno));
363		ret = -1;
364		break;
365	case SHOW_TREE_FN_ERR:
366		ret = -1;
367		break;
368	default:
369		ret = 0;
370	}
371
372	if (json_output)
373		jsonw_end_array(json_wtr);
374
375	free(cgroup_alloced);
376
377	return ret;
378}
379
380static int do_attach(int argc, char **argv)
381{
382	enum bpf_attach_type attach_type;
383	int cgroup_fd, prog_fd;
384	int attach_flags = 0;
385	int ret = -1;
386	int i;
387
388	if (argc < 4) {
389		p_err("too few parameters for cgroup attach");
390		goto exit;
391	}
392
393	cgroup_fd = open(argv[0], O_RDONLY);
394	if (cgroup_fd < 0) {
395		p_err("can't open cgroup %s", argv[0]);
396		goto exit;
397	}
398
399	attach_type = parse_attach_type(argv[1]);
400	if (attach_type == __MAX_BPF_ATTACH_TYPE) {
401		p_err("invalid attach type");
402		goto exit_cgroup;
403	}
404
405	argc -= 2;
406	argv = &argv[2];
407	prog_fd = prog_parse_fd(&argc, &argv);
408	if (prog_fd < 0)
409		goto exit_cgroup;
410
411	for (i = 0; i < argc; i++) {
412		if (is_prefix(argv[i], "multi")) {
413			attach_flags |= BPF_F_ALLOW_MULTI;
414		} else if (is_prefix(argv[i], "override")) {
415			attach_flags |= BPF_F_ALLOW_OVERRIDE;
416		} else {
417			p_err("unknown option: %s", argv[i]);
418			goto exit_cgroup;
419		}
420	}
421
422	if (bpf_prog_attach(prog_fd, cgroup_fd, attach_type, attach_flags)) {
423		p_err("failed to attach program");
424		goto exit_prog;
425	}
426
427	if (json_output)
428		jsonw_null(json_wtr);
429
430	ret = 0;
431
432exit_prog:
433	close(prog_fd);
434exit_cgroup:
435	close(cgroup_fd);
436exit:
437	return ret;
438}
439
440static int do_detach(int argc, char **argv)
441{
442	enum bpf_attach_type attach_type;
443	int prog_fd, cgroup_fd;
444	int ret = -1;
445
446	if (argc < 4) {
447		p_err("too few parameters for cgroup detach");
448		goto exit;
449	}
450
451	cgroup_fd = open(argv[0], O_RDONLY);
452	if (cgroup_fd < 0) {
453		p_err("can't open cgroup %s", argv[0]);
454		goto exit;
455	}
456
457	attach_type = parse_attach_type(argv[1]);
458	if (attach_type == __MAX_BPF_ATTACH_TYPE) {
459		p_err("invalid attach type");
460		goto exit_cgroup;
461	}
462
463	argc -= 2;
464	argv = &argv[2];
465	prog_fd = prog_parse_fd(&argc, &argv);
466	if (prog_fd < 0)
467		goto exit_cgroup;
468
469	if (bpf_prog_detach2(prog_fd, cgroup_fd, attach_type)) {
470		p_err("failed to detach program");
471		goto exit_prog;
472	}
473
474	if (json_output)
475		jsonw_null(json_wtr);
476
477	ret = 0;
478
479exit_prog:
480	close(prog_fd);
481exit_cgroup:
482	close(cgroup_fd);
483exit:
484	return ret;
485}
486
487static int do_help(int argc, char **argv)
488{
489	if (json_output) {
490		jsonw_null(json_wtr);
491		return 0;
492	}
493
494	fprintf(stderr,
495		"Usage: %1$s %2$s { show | list } CGROUP [**effective**]\n"
496		"       %1$s %2$s tree [CGROUP_ROOT] [**effective**]\n"
497		"       %1$s %2$s attach CGROUP ATTACH_TYPE PROG [ATTACH_FLAGS]\n"
498		"       %1$s %2$s detach CGROUP ATTACH_TYPE PROG\n"
499		"       %1$s %2$s help\n"
500		"\n"
501		HELP_SPEC_ATTACH_TYPES "\n"
502		"       " HELP_SPEC_ATTACH_FLAGS "\n"
503		"       " HELP_SPEC_PROGRAM "\n"
504		"       " HELP_SPEC_OPTIONS "\n"
505		"",
506		bin_name, argv[-2]);
 
 
507
508	return 0;
509}
510
511static const struct cmd cmds[] = {
512	{ "show",	do_show },
513	{ "list",	do_show },
514	{ "tree",       do_show_tree },
515	{ "attach",	do_attach },
516	{ "detach",	do_detach },
517	{ "help",	do_help },
518	{ 0 }
519};
520
521int do_cgroup(int argc, char **argv)
522{
523	return cmd_select(cmds, argc, argv, do_help);
524}
v5.4
  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}