Commit 831a0aaf authored by Quentin Monnet's avatar Quentin Monnet Committed by David S. Miller
Browse files

tools: bpftool: add JSON output for `bpftool map *` commands 



Reuse the json_writer API introduced in an earlier commit to make
bpftool able to generate JSON output on
`bpftool map { show | dump | lookup | getnext }` commands. Remaining
commands produce no output.

Some functions have been spit into plain-output and JSON versions in
order to remain readable.

Outputs for sample maps have been successfully tested against a JSON
validator.

Signed-off-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f05e2c32

tools/bpf/bpftool/map.c

+129 −20
Original line number Diff line number Diff line
@@ -205,7 +205,44 @@ map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len) 
	return fd;

}



static void print_entry(struct bpf_map_info *info, unsigned char *key,

static void print_entry_json(struct bpf_map_info *info, unsigned char *key,

			     unsigned char *value)

{

	jsonw_start_object(json_wtr);



	if (!map_is_per_cpu(info->type)) {

		jsonw_name(json_wtr, "key");

		print_hex_data_json(key, info->key_size);

		jsonw_name(json_wtr, "value");

		print_hex_data_json(value, info->value_size);

	} else {

		unsigned int i, n;



		n = get_possible_cpus();



		jsonw_name(json_wtr, "key");

		print_hex_data_json(key, info->key_size);



		jsonw_name(json_wtr, "values");

		jsonw_start_array(json_wtr);

		for (i = 0; i < n; i++) {

			jsonw_start_object(json_wtr);



			jsonw_int_field(json_wtr, "cpu", i);



			jsonw_name(json_wtr, "value");

			print_hex_data_json(value + i * info->value_size,

					    info->value_size);



			jsonw_end_object(json_wtr);

		}

		jsonw_end_array(json_wtr);

	}



	jsonw_end_object(json_wtr);

}



static void print_entry_plain(struct bpf_map_info *info, unsigned char *key,

			      unsigned char *value)

{

	if (!map_is_per_cpu(info->type)) {
@@ -370,7 +407,41 @@ static int parse_elem(char **argv, struct bpf_map_info *info, 
	return -1;

}



static int show_map_close(int fd, struct bpf_map_info *info)

static int show_map_close_json(int fd, struct bpf_map_info *info)

{

	char *memlock;



	memlock = get_fdinfo(fd, "memlock");

	close(fd);



	jsonw_start_object(json_wtr);



	jsonw_uint_field(json_wtr, "id", info->id);

	if (info->type < ARRAY_SIZE(map_type_name))

		jsonw_string_field(json_wtr, "type",

				   map_type_name[info->type]);

	else

		jsonw_uint_field(json_wtr, "type", info->type);



	if (*info->name)

		jsonw_string_field(json_wtr, "name", info->name);



	jsonw_name(json_wtr, "flags");

	jsonw_printf(json_wtr, "%#x", info->map_flags);

	jsonw_uint_field(json_wtr, "bytes_key", info->key_size);

	jsonw_uint_field(json_wtr, "bytes_value", info->value_size);

	jsonw_uint_field(json_wtr, "max_entries", info->max_entries);



	if (memlock)

		jsonw_int_field(json_wtr, "bytes_memlock", atoi(memlock));

	free(memlock);



	jsonw_end_object(json_wtr);



	return 0;

}



static int show_map_close_plain(int fd, struct bpf_map_info *info)

{

	char *memlock;
@@ -412,12 +483,17 @@ static int do_show(int argc, char **argv) 
		if (fd < 0)

			return -1;



		return show_map_close(fd, &info);

		if (json_output)

			return show_map_close_json(fd, &info);

		else

			return show_map_close_plain(fd, &info);

	}



	if (argc)

		return BAD_ARG();



	if (json_output)

		jsonw_start_array(json_wtr);

	while (true) {

		err = bpf_map_get_next_id(id, &id);

		if (err) {
@@ -443,8 +519,13 @@ static int do_show(int argc, char **argv) 
			return -1;

		}



		show_map_close(fd, &info);

		if (json_output)

			show_map_close_json(fd, &info);

		else

			show_map_close_plain(fd, &info);

	}

	if (json_output)

		jsonw_end_array(json_wtr);



	return errno == ENOENT ? 0 : -1;

}
@@ -480,6 +561,8 @@ static int do_dump(int argc, char **argv) 
	}



	prev_key = NULL;

	if (json_output)

		jsonw_start_array(json_wtr);

	while (true) {

		err = bpf_map_get_next_key(fd, prev_key, key);

		if (err) {
@@ -489,7 +572,10 @@ static int do_dump(int argc, char **argv) 
		}



		if (!bpf_map_lookup_elem(fd, key, value)) {

			print_entry(&info, key, value);

			if (json_output)

				print_entry_json(&info, key, value);

			else

				print_entry_plain(&info, key, value);

		} else {

			info("can't lookup element with key: ");

			fprint_hex(stderr, key, info.key_size, " ");
@@ -500,7 +586,11 @@ static int do_dump(int argc, char **argv) 
		num_elems++;

	}



	printf("Found %u element%s\n", num_elems, num_elems != 1 ? "s" : "");

	if (json_output)

		jsonw_end_array(json_wtr);

	else

		printf("Found %u element%s\n", num_elems,

		       num_elems != 1 ? "s" : "");



exit_free:

	free(key);
@@ -584,11 +674,18 @@ static int do_lookup(int argc, char **argv) 


	err = bpf_map_lookup_elem(fd, key, value);

	if (!err) {

		print_entry(&info, key, value);

		if (json_output)

			print_entry_json(&info, key, value);

		else

			print_entry_plain(&info, key, value);

	} else if (errno == ENOENT) {

		if (json_output) {

			jsonw_null(json_wtr);

		} else {

			printf("key:\n");

			fprint_hex(stdout, key, info.key_size, " ");

			printf("\n\nNot found\n");

		}

	} else {

		err("lookup failed: %s\n", strerror(errno));

	}
@@ -640,6 +737,18 @@ static int do_getnext(int argc, char **argv) 
		goto exit_free;

	}



	if (json_output) {

		jsonw_start_object(json_wtr);

		if (key) {

			jsonw_name(json_wtr, "key");

			print_hex_data_json(key, info.key_size);

		} else {

			jsonw_null_field(json_wtr, "key");

		}

		jsonw_name(json_wtr, "next_key");

		print_hex_data_json(nextkey, info.key_size);

		jsonw_end_object(json_wtr);

	} else {

		if (key) {

			printf("key:\n");

			fprint_hex(stdout, key, info.key_size, " ");
@@ -647,10 +756,10 @@ static int do_getnext(int argc, char **argv) 
		} else {

			printf("key: None\n");

		}



		printf("next key:\n");

		fprint_hex(stdout, nextkey, info.key_size, " ");

		printf("\n");

	}



exit_free:

	free(nextkey);

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