xref: /linux/tools/bpf/bpftool/map.c (revision 0c90f2243ec67eeacf9624ae52ab43c734fe0e93)
1 /*
2  * Copyright (C) 2017 Netronome Systems, Inc.
3  *
4  * This software is dual licensed under the GNU General License Version 2,
5  * June 1991 as shown in the file COPYING in the top-level directory of this
6  * source tree or the BSD 2-Clause License provided below.  You have the
7  * option to license this software under the complete terms of either license.
8  *
9  * The BSD 2-Clause License:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      1. Redistributions of source code must retain the above
16  *         copyright notice, this list of conditions and the following
17  *         disclaimer.
18  *
19  *      2. Redistributions in binary form must reproduce the above
20  *         copyright notice, this list of conditions and the following
21  *         disclaimer in the documentation and/or other materials
22  *         provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33 
34 /* Author: Jakub Kicinski <kubakici@wp.pl> */
35 
36 #include <assert.h>
37 #include <ctype.h>
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <stdbool.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <unistd.h>
45 #include <sys/types.h>
46 #include <sys/stat.h>
47 
48 #include <bpf.h>
49 
50 #include "main.h"
51 
52 static const char * const map_type_name[] = {
53 	[BPF_MAP_TYPE_UNSPEC]		= "unspec",
54 	[BPF_MAP_TYPE_HASH]		= "hash",
55 	[BPF_MAP_TYPE_ARRAY]		= "array",
56 	[BPF_MAP_TYPE_PROG_ARRAY]	= "prog_array",
57 	[BPF_MAP_TYPE_PERF_EVENT_ARRAY]	= "perf_event_array",
58 	[BPF_MAP_TYPE_PERCPU_HASH]	= "percpu_hash",
59 	[BPF_MAP_TYPE_PERCPU_ARRAY]	= "percpu_array",
60 	[BPF_MAP_TYPE_STACK_TRACE]	= "stack_trace",
61 	[BPF_MAP_TYPE_CGROUP_ARRAY]	= "cgroup_array",
62 	[BPF_MAP_TYPE_LRU_HASH]		= "lru_hash",
63 	[BPF_MAP_TYPE_LRU_PERCPU_HASH]	= "lru_percpu_hash",
64 	[BPF_MAP_TYPE_LPM_TRIE]		= "lpm_trie",
65 	[BPF_MAP_TYPE_ARRAY_OF_MAPS]	= "array_of_maps",
66 	[BPF_MAP_TYPE_HASH_OF_MAPS]	= "hash_of_maps",
67 	[BPF_MAP_TYPE_DEVMAP]		= "devmap",
68 	[BPF_MAP_TYPE_SOCKMAP]		= "sockmap",
69 	[BPF_MAP_TYPE_CPUMAP]		= "cpumap",
70 };
71 
72 static unsigned int get_possible_cpus(void)
73 {
74 	static unsigned int result;
75 	char buf[128];
76 	long int n;
77 	char *ptr;
78 	int fd;
79 
80 	if (result)
81 		return result;
82 
83 	fd = open("/sys/devices/system/cpu/possible", O_RDONLY);
84 	if (fd < 0) {
85 		p_err("can't open sysfs possible cpus");
86 		exit(-1);
87 	}
88 
89 	n = read(fd, buf, sizeof(buf));
90 	if (n < 2) {
91 		p_err("can't read sysfs possible cpus");
92 		exit(-1);
93 	}
94 	close(fd);
95 
96 	if (n == sizeof(buf)) {
97 		p_err("read sysfs possible cpus overflow");
98 		exit(-1);
99 	}
100 
101 	ptr = buf;
102 	n = 0;
103 	while (*ptr && *ptr != '\n') {
104 		unsigned int a, b;
105 
106 		if (sscanf(ptr, "%u-%u", &a, &b) == 2) {
107 			n += b - a + 1;
108 
109 			ptr = strchr(ptr, '-') + 1;
110 		} else if (sscanf(ptr, "%u", &a) == 1) {
111 			n++;
112 		} else {
113 			assert(0);
114 		}
115 
116 		while (isdigit(*ptr))
117 			ptr++;
118 		if (*ptr == ',')
119 			ptr++;
120 	}
121 
122 	result = n;
123 
124 	return result;
125 }
126 
127 static bool map_is_per_cpu(__u32 type)
128 {
129 	return type == BPF_MAP_TYPE_PERCPU_HASH ||
130 	       type == BPF_MAP_TYPE_PERCPU_ARRAY ||
131 	       type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
132 }
133 
134 static bool map_is_map_of_maps(__u32 type)
135 {
136 	return type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
137 	       type == BPF_MAP_TYPE_HASH_OF_MAPS;
138 }
139 
140 static bool map_is_map_of_progs(__u32 type)
141 {
142 	return type == BPF_MAP_TYPE_PROG_ARRAY;
143 }
144 
145 static void *alloc_value(struct bpf_map_info *info)
146 {
147 	if (map_is_per_cpu(info->type))
148 		return malloc(info->value_size * get_possible_cpus());
149 	else
150 		return malloc(info->value_size);
151 }
152 
153 static int map_parse_fd(int *argc, char ***argv)
154 {
155 	int fd;
156 
157 	if (is_prefix(**argv, "id")) {
158 		unsigned int id;
159 		char *endptr;
160 
161 		NEXT_ARGP();
162 
163 		id = strtoul(**argv, &endptr, 0);
164 		if (*endptr) {
165 			p_err("can't parse %s as ID", **argv);
166 			return -1;
167 		}
168 		NEXT_ARGP();
169 
170 		fd = bpf_map_get_fd_by_id(id);
171 		if (fd < 0)
172 			p_err("get map by id (%u): %s", id, strerror(errno));
173 		return fd;
174 	} else if (is_prefix(**argv, "pinned")) {
175 		char *path;
176 
177 		NEXT_ARGP();
178 
179 		path = **argv;
180 		NEXT_ARGP();
181 
182 		return open_obj_pinned_any(path, BPF_OBJ_MAP);
183 	}
184 
185 	p_err("expected 'id' or 'pinned', got: '%s'?", **argv);
186 	return -1;
187 }
188 
189 static int
190 map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len)
191 {
192 	int err;
193 	int fd;
194 
195 	fd = map_parse_fd(argc, argv);
196 	if (fd < 0)
197 		return -1;
198 
199 	err = bpf_obj_get_info_by_fd(fd, info, info_len);
200 	if (err) {
201 		p_err("can't get map info: %s", strerror(errno));
202 		close(fd);
203 		return err;
204 	}
205 
206 	return fd;
207 }
208 
209 static void print_entry_json(struct bpf_map_info *info, unsigned char *key,
210 			     unsigned char *value)
211 {
212 	jsonw_start_object(json_wtr);
213 
214 	if (!map_is_per_cpu(info->type)) {
215 		jsonw_name(json_wtr, "key");
216 		print_hex_data_json(key, info->key_size);
217 		jsonw_name(json_wtr, "value");
218 		print_hex_data_json(value, info->value_size);
219 	} else {
220 		unsigned int i, n;
221 
222 		n = get_possible_cpus();
223 
224 		jsonw_name(json_wtr, "key");
225 		print_hex_data_json(key, info->key_size);
226 
227 		jsonw_name(json_wtr, "values");
228 		jsonw_start_array(json_wtr);
229 		for (i = 0; i < n; i++) {
230 			jsonw_start_object(json_wtr);
231 
232 			jsonw_int_field(json_wtr, "cpu", i);
233 
234 			jsonw_name(json_wtr, "value");
235 			print_hex_data_json(value + i * info->value_size,
236 					    info->value_size);
237 
238 			jsonw_end_object(json_wtr);
239 		}
240 		jsonw_end_array(json_wtr);
241 	}
242 
243 	jsonw_end_object(json_wtr);
244 }
245 
246 static void print_entry_plain(struct bpf_map_info *info, unsigned char *key,
247 			      unsigned char *value)
248 {
249 	if (!map_is_per_cpu(info->type)) {
250 		bool single_line, break_names;
251 
252 		break_names = info->key_size > 16 || info->value_size > 16;
253 		single_line = info->key_size + info->value_size <= 24 &&
254 			!break_names;
255 
256 		printf("key:%c", break_names ? '\n' : ' ');
257 		fprint_hex(stdout, key, info->key_size, " ");
258 
259 		printf(single_line ? "  " : "\n");
260 
261 		printf("value:%c", break_names ? '\n' : ' ');
262 		fprint_hex(stdout, value, info->value_size, " ");
263 
264 		printf("\n");
265 	} else {
266 		unsigned int i, n;
267 
268 		n = get_possible_cpus();
269 
270 		printf("key:\n");
271 		fprint_hex(stdout, key, info->key_size, " ");
272 		printf("\n");
273 		for (i = 0; i < n; i++) {
274 			printf("value (CPU %02d):%c",
275 			       i, info->value_size > 16 ? '\n' : ' ');
276 			fprint_hex(stdout, value + i * info->value_size,
277 				   info->value_size, " ");
278 			printf("\n");
279 		}
280 	}
281 }
282 
283 static char **parse_bytes(char **argv, const char *name, unsigned char *val,
284 			  unsigned int n)
285 {
286 	unsigned int i = 0, base = 0;
287 	char *endptr;
288 
289 	if (is_prefix(*argv, "hex")) {
290 		base = 16;
291 		argv++;
292 	}
293 
294 	while (i < n && argv[i]) {
295 		val[i] = strtoul(argv[i], &endptr, base);
296 		if (*endptr) {
297 			p_err("error parsing byte: %s", argv[i]);
298 			return NULL;
299 		}
300 		i++;
301 	}
302 
303 	if (i != n) {
304 		p_err("%s expected %d bytes got %d", name, n, i);
305 		return NULL;
306 	}
307 
308 	return argv + i;
309 }
310 
311 static int parse_elem(char **argv, struct bpf_map_info *info,
312 		      void *key, void *value, __u32 key_size, __u32 value_size,
313 		      __u32 *flags, __u32 **value_fd)
314 {
315 	if (!*argv) {
316 		if (!key && !value)
317 			return 0;
318 		p_err("did not find %s", key ? "key" : "value");
319 		return -1;
320 	}
321 
322 	if (is_prefix(*argv, "key")) {
323 		if (!key) {
324 			if (key_size)
325 				p_err("duplicate key");
326 			else
327 				p_err("unnecessary key");
328 			return -1;
329 		}
330 
331 		argv = parse_bytes(argv + 1, "key", key, key_size);
332 		if (!argv)
333 			return -1;
334 
335 		return parse_elem(argv, info, NULL, value, key_size, value_size,
336 				  flags, value_fd);
337 	} else if (is_prefix(*argv, "value")) {
338 		int fd;
339 
340 		if (!value) {
341 			if (value_size)
342 				p_err("duplicate value");
343 			else
344 				p_err("unnecessary value");
345 			return -1;
346 		}
347 
348 		argv++;
349 
350 		if (map_is_map_of_maps(info->type)) {
351 			int argc = 2;
352 
353 			if (value_size != 4) {
354 				p_err("value smaller than 4B for map in map?");
355 				return -1;
356 			}
357 			if (!argv[0] || !argv[1]) {
358 				p_err("not enough value arguments for map in map");
359 				return -1;
360 			}
361 
362 			fd = map_parse_fd(&argc, &argv);
363 			if (fd < 0)
364 				return -1;
365 
366 			*value_fd = value;
367 			**value_fd = fd;
368 		} else if (map_is_map_of_progs(info->type)) {
369 			int argc = 2;
370 
371 			if (value_size != 4) {
372 				p_err("value smaller than 4B for map of progs?");
373 				return -1;
374 			}
375 			if (!argv[0] || !argv[1]) {
376 				p_err("not enough value arguments for map of progs");
377 				return -1;
378 			}
379 
380 			fd = prog_parse_fd(&argc, &argv);
381 			if (fd < 0)
382 				return -1;
383 
384 			*value_fd = value;
385 			**value_fd = fd;
386 		} else {
387 			argv = parse_bytes(argv, "value", value, value_size);
388 			if (!argv)
389 				return -1;
390 		}
391 
392 		return parse_elem(argv, info, key, NULL, key_size, value_size,
393 				  flags, NULL);
394 	} else if (is_prefix(*argv, "any") || is_prefix(*argv, "noexist") ||
395 		   is_prefix(*argv, "exist")) {
396 		if (!flags) {
397 			p_err("flags specified multiple times: %s", *argv);
398 			return -1;
399 		}
400 
401 		if (is_prefix(*argv, "any"))
402 			*flags = BPF_ANY;
403 		else if (is_prefix(*argv, "noexist"))
404 			*flags = BPF_NOEXIST;
405 		else if (is_prefix(*argv, "exist"))
406 			*flags = BPF_EXIST;
407 
408 		return parse_elem(argv + 1, info, key, value, key_size,
409 				  value_size, NULL, value_fd);
410 	}
411 
412 	p_err("expected key or value, got: %s", *argv);
413 	return -1;
414 }
415 
416 static int show_map_close_json(int fd, struct bpf_map_info *info)
417 {
418 	char *memlock;
419 
420 	memlock = get_fdinfo(fd, "memlock");
421 	close(fd);
422 
423 	jsonw_start_object(json_wtr);
424 
425 	jsonw_uint_field(json_wtr, "id", info->id);
426 	if (info->type < ARRAY_SIZE(map_type_name))
427 		jsonw_string_field(json_wtr, "type",
428 				   map_type_name[info->type]);
429 	else
430 		jsonw_uint_field(json_wtr, "type", info->type);
431 
432 	if (*info->name)
433 		jsonw_string_field(json_wtr, "name", info->name);
434 
435 	jsonw_name(json_wtr, "flags");
436 	jsonw_printf(json_wtr, "%d", info->map_flags);
437 
438 	print_dev_json(info->ifindex, info->netns_dev, info->netns_ino);
439 
440 	jsonw_uint_field(json_wtr, "bytes_key", info->key_size);
441 	jsonw_uint_field(json_wtr, "bytes_value", info->value_size);
442 	jsonw_uint_field(json_wtr, "max_entries", info->max_entries);
443 
444 	if (memlock)
445 		jsonw_int_field(json_wtr, "bytes_memlock", atoi(memlock));
446 	free(memlock);
447 
448 	if (!hash_empty(map_table.table)) {
449 		struct pinned_obj *obj;
450 
451 		jsonw_name(json_wtr, "pinned");
452 		jsonw_start_array(json_wtr);
453 		hash_for_each_possible(map_table.table, obj, hash, info->id) {
454 			if (obj->id == info->id)
455 				jsonw_string(json_wtr, obj->path);
456 		}
457 		jsonw_end_array(json_wtr);
458 	}
459 
460 	jsonw_end_object(json_wtr);
461 
462 	return 0;
463 }
464 
465 static int show_map_close_plain(int fd, struct bpf_map_info *info)
466 {
467 	char *memlock;
468 
469 	memlock = get_fdinfo(fd, "memlock");
470 	close(fd);
471 
472 	printf("%u: ", info->id);
473 	if (info->type < ARRAY_SIZE(map_type_name))
474 		printf("%s  ", map_type_name[info->type]);
475 	else
476 		printf("type %u  ", info->type);
477 
478 	if (*info->name)
479 		printf("name %s  ", info->name);
480 
481 	printf("flags 0x%x", info->map_flags);
482 	print_dev_plain(info->ifindex, info->netns_dev, info->netns_ino);
483 	printf("\n");
484 	printf("\tkey %uB  value %uB  max_entries %u",
485 	       info->key_size, info->value_size, info->max_entries);
486 
487 	if (memlock)
488 		printf("  memlock %sB", memlock);
489 	free(memlock);
490 
491 	printf("\n");
492 	if (!hash_empty(map_table.table)) {
493 		struct pinned_obj *obj;
494 
495 		hash_for_each_possible(map_table.table, obj, hash, info->id) {
496 			if (obj->id == info->id)
497 				printf("\tpinned %s\n", obj->path);
498 		}
499 	}
500 	return 0;
501 }
502 
503 static int do_show(int argc, char **argv)
504 {
505 	struct bpf_map_info info = {};
506 	__u32 len = sizeof(info);
507 	__u32 id = 0;
508 	int err;
509 	int fd;
510 
511 	if (show_pinned)
512 		build_pinned_obj_table(&map_table, BPF_OBJ_MAP);
513 
514 	if (argc == 2) {
515 		fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
516 		if (fd < 0)
517 			return -1;
518 
519 		if (json_output)
520 			return show_map_close_json(fd, &info);
521 		else
522 			return show_map_close_plain(fd, &info);
523 	}
524 
525 	if (argc)
526 		return BAD_ARG();
527 
528 	if (json_output)
529 		jsonw_start_array(json_wtr);
530 	while (true) {
531 		err = bpf_map_get_next_id(id, &id);
532 		if (err) {
533 			if (errno == ENOENT)
534 				break;
535 			p_err("can't get next map: %s%s", strerror(errno),
536 			      errno == EINVAL ? " -- kernel too old?" : "");
537 			break;
538 		}
539 
540 		fd = bpf_map_get_fd_by_id(id);
541 		if (fd < 0) {
542 			if (errno == ENOENT)
543 				continue;
544 			p_err("can't get map by id (%u): %s",
545 			      id, strerror(errno));
546 			break;
547 		}
548 
549 		err = bpf_obj_get_info_by_fd(fd, &info, &len);
550 		if (err) {
551 			p_err("can't get map info: %s", strerror(errno));
552 			close(fd);
553 			break;
554 		}
555 
556 		if (json_output)
557 			show_map_close_json(fd, &info);
558 		else
559 			show_map_close_plain(fd, &info);
560 	}
561 	if (json_output)
562 		jsonw_end_array(json_wtr);
563 
564 	return errno == ENOENT ? 0 : -1;
565 }
566 
567 static int do_dump(int argc, char **argv)
568 {
569 	void *key, *value, *prev_key;
570 	unsigned int num_elems = 0;
571 	struct bpf_map_info info = {};
572 	__u32 len = sizeof(info);
573 	int err;
574 	int fd;
575 
576 	if (argc != 2)
577 		usage();
578 
579 	fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
580 	if (fd < 0)
581 		return -1;
582 
583 	if (map_is_map_of_maps(info.type) || map_is_map_of_progs(info.type)) {
584 		p_err("Dumping maps of maps and program maps not supported");
585 		close(fd);
586 		return -1;
587 	}
588 
589 	key = malloc(info.key_size);
590 	value = alloc_value(&info);
591 	if (!key || !value) {
592 		p_err("mem alloc failed");
593 		err = -1;
594 		goto exit_free;
595 	}
596 
597 	prev_key = NULL;
598 	if (json_output)
599 		jsonw_start_array(json_wtr);
600 	while (true) {
601 		err = bpf_map_get_next_key(fd, prev_key, key);
602 		if (err) {
603 			if (errno == ENOENT)
604 				err = 0;
605 			break;
606 		}
607 
608 		if (!bpf_map_lookup_elem(fd, key, value)) {
609 			if (json_output)
610 				print_entry_json(&info, key, value);
611 			else
612 				print_entry_plain(&info, key, value);
613 		} else {
614 			if (json_output) {
615 				jsonw_name(json_wtr, "key");
616 				print_hex_data_json(key, info.key_size);
617 				jsonw_name(json_wtr, "value");
618 				jsonw_start_object(json_wtr);
619 				jsonw_string_field(json_wtr, "error",
620 						   "can't lookup element");
621 				jsonw_end_object(json_wtr);
622 			} else {
623 				p_info("can't lookup element with key: ");
624 				fprint_hex(stderr, key, info.key_size, " ");
625 				fprintf(stderr, "\n");
626 			}
627 		}
628 
629 		prev_key = key;
630 		num_elems++;
631 	}
632 
633 	if (json_output)
634 		jsonw_end_array(json_wtr);
635 	else
636 		printf("Found %u element%s\n", num_elems,
637 		       num_elems != 1 ? "s" : "");
638 
639 exit_free:
640 	free(key);
641 	free(value);
642 	close(fd);
643 
644 	return err;
645 }
646 
647 static int do_update(int argc, char **argv)
648 {
649 	struct bpf_map_info info = {};
650 	__u32 len = sizeof(info);
651 	__u32 *value_fd = NULL;
652 	__u32 flags = BPF_ANY;
653 	void *key, *value;
654 	int fd, err;
655 
656 	if (argc < 2)
657 		usage();
658 
659 	fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
660 	if (fd < 0)
661 		return -1;
662 
663 	key = malloc(info.key_size);
664 	value = alloc_value(&info);
665 	if (!key || !value) {
666 		p_err("mem alloc failed");
667 		err = -1;
668 		goto exit_free;
669 	}
670 
671 	err = parse_elem(argv, &info, key, value, info.key_size,
672 			 info.value_size, &flags, &value_fd);
673 	if (err)
674 		goto exit_free;
675 
676 	err = bpf_map_update_elem(fd, key, value, flags);
677 	if (err) {
678 		p_err("update failed: %s", strerror(errno));
679 		goto exit_free;
680 	}
681 
682 exit_free:
683 	if (value_fd)
684 		close(*value_fd);
685 	free(key);
686 	free(value);
687 	close(fd);
688 
689 	if (!err && json_output)
690 		jsonw_null(json_wtr);
691 	return err;
692 }
693 
694 static int do_lookup(int argc, char **argv)
695 {
696 	struct bpf_map_info info = {};
697 	__u32 len = sizeof(info);
698 	void *key, *value;
699 	int err;
700 	int fd;
701 
702 	if (argc < 2)
703 		usage();
704 
705 	fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
706 	if (fd < 0)
707 		return -1;
708 
709 	key = malloc(info.key_size);
710 	value = alloc_value(&info);
711 	if (!key || !value) {
712 		p_err("mem alloc failed");
713 		err = -1;
714 		goto exit_free;
715 	}
716 
717 	err = parse_elem(argv, &info, key, NULL, info.key_size, 0, NULL, NULL);
718 	if (err)
719 		goto exit_free;
720 
721 	err = bpf_map_lookup_elem(fd, key, value);
722 	if (!err) {
723 		if (json_output)
724 			print_entry_json(&info, key, value);
725 		else
726 			print_entry_plain(&info, key, value);
727 	} else if (errno == ENOENT) {
728 		if (json_output) {
729 			jsonw_null(json_wtr);
730 		} else {
731 			printf("key:\n");
732 			fprint_hex(stdout, key, info.key_size, " ");
733 			printf("\n\nNot found\n");
734 		}
735 	} else {
736 		p_err("lookup failed: %s", strerror(errno));
737 	}
738 
739 exit_free:
740 	free(key);
741 	free(value);
742 	close(fd);
743 
744 	return err;
745 }
746 
747 static int do_getnext(int argc, char **argv)
748 {
749 	struct bpf_map_info info = {};
750 	__u32 len = sizeof(info);
751 	void *key, *nextkey;
752 	int err;
753 	int fd;
754 
755 	if (argc < 2)
756 		usage();
757 
758 	fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
759 	if (fd < 0)
760 		return -1;
761 
762 	key = malloc(info.key_size);
763 	nextkey = malloc(info.key_size);
764 	if (!key || !nextkey) {
765 		p_err("mem alloc failed");
766 		err = -1;
767 		goto exit_free;
768 	}
769 
770 	if (argc) {
771 		err = parse_elem(argv, &info, key, NULL, info.key_size, 0,
772 				 NULL, NULL);
773 		if (err)
774 			goto exit_free;
775 	} else {
776 		free(key);
777 		key = NULL;
778 	}
779 
780 	err = bpf_map_get_next_key(fd, key, nextkey);
781 	if (err) {
782 		p_err("can't get next key: %s", strerror(errno));
783 		goto exit_free;
784 	}
785 
786 	if (json_output) {
787 		jsonw_start_object(json_wtr);
788 		if (key) {
789 			jsonw_name(json_wtr, "key");
790 			print_hex_data_json(key, info.key_size);
791 		} else {
792 			jsonw_null_field(json_wtr, "key");
793 		}
794 		jsonw_name(json_wtr, "next_key");
795 		print_hex_data_json(nextkey, info.key_size);
796 		jsonw_end_object(json_wtr);
797 	} else {
798 		if (key) {
799 			printf("key:\n");
800 			fprint_hex(stdout, key, info.key_size, " ");
801 			printf("\n");
802 		} else {
803 			printf("key: None\n");
804 		}
805 		printf("next key:\n");
806 		fprint_hex(stdout, nextkey, info.key_size, " ");
807 		printf("\n");
808 	}
809 
810 exit_free:
811 	free(nextkey);
812 	free(key);
813 	close(fd);
814 
815 	return err;
816 }
817 
818 static int do_delete(int argc, char **argv)
819 {
820 	struct bpf_map_info info = {};
821 	__u32 len = sizeof(info);
822 	void *key;
823 	int err;
824 	int fd;
825 
826 	if (argc < 2)
827 		usage();
828 
829 	fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
830 	if (fd < 0)
831 		return -1;
832 
833 	key = malloc(info.key_size);
834 	if (!key) {
835 		p_err("mem alloc failed");
836 		err = -1;
837 		goto exit_free;
838 	}
839 
840 	err = parse_elem(argv, &info, key, NULL, info.key_size, 0, NULL, NULL);
841 	if (err)
842 		goto exit_free;
843 
844 	err = bpf_map_delete_elem(fd, key);
845 	if (err)
846 		p_err("delete failed: %s", strerror(errno));
847 
848 exit_free:
849 	free(key);
850 	close(fd);
851 
852 	if (!err && json_output)
853 		jsonw_null(json_wtr);
854 	return err;
855 }
856 
857 static int do_pin(int argc, char **argv)
858 {
859 	int err;
860 
861 	err = do_pin_any(argc, argv, bpf_map_get_fd_by_id);
862 	if (!err && json_output)
863 		jsonw_null(json_wtr);
864 	return err;
865 }
866 
867 static int do_help(int argc, char **argv)
868 {
869 	if (json_output) {
870 		jsonw_null(json_wtr);
871 		return 0;
872 	}
873 
874 	fprintf(stderr,
875 		"Usage: %s %s { show | list }   [MAP]\n"
876 		"       %s %s dump    MAP\n"
877 		"       %s %s update  MAP  key [hex] BYTES value [hex] VALUE [UPDATE_FLAGS]\n"
878 		"       %s %s lookup  MAP  key [hex] BYTES\n"
879 		"       %s %s getnext MAP [key [hex] BYTES]\n"
880 		"       %s %s delete  MAP  key [hex] BYTES\n"
881 		"       %s %s pin     MAP  FILE\n"
882 		"       %s %s help\n"
883 		"\n"
884 		"       MAP := { id MAP_ID | pinned FILE }\n"
885 		"       " HELP_SPEC_PROGRAM "\n"
886 		"       VALUE := { BYTES | MAP | PROG }\n"
887 		"       UPDATE_FLAGS := { any | exist | noexist }\n"
888 		"       " HELP_SPEC_OPTIONS "\n"
889 		"",
890 		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
891 		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
892 		bin_name, argv[-2], bin_name, argv[-2]);
893 
894 	return 0;
895 }
896 
897 static const struct cmd cmds[] = {
898 	{ "show",	do_show },
899 	{ "list",	do_show },
900 	{ "help",	do_help },
901 	{ "dump",	do_dump },
902 	{ "update",	do_update },
903 	{ "lookup",	do_lookup },
904 	{ "getnext",	do_getnext },
905 	{ "delete",	do_delete },
906 	{ "pin",	do_pin },
907 	{ 0 }
908 };
909 
910 int do_map(int argc, char **argv)
911 {
912 	return cmd_select(cmds, argc, argv, do_help);
913 }
914