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Commit 699c86d6 authored by Yonghong Song's avatar Yonghong Song Committed by Daniel Borkmann
Browse files

bpf: btf: add pretty print for hash/lru_hash maps 



Commit a26ca7c9 ("bpf: btf: Add pretty print support to
the basic arraymap") added pretty print support to array map.
This patch adds pretty print for hash and lru_hash maps.
The following example shows the pretty-print result of
a pinned hashmap:

    struct map_value {
            int count_a;
            int count_b;
    };

    cat /sys/fs/bpf/pinned_hash_map:

    87907: {87907,87908}
    57354: {37354,57355}
    76625: {76625,76626}
    ...

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent dc1508a5

kernel/bpf/hashtab.c

+44 −0
Original line number Diff line number Diff line
@@ -11,9 +11,11 @@ 
 * General Public License for more details.

 */

#include <linux/bpf.h>

#include <linux/btf.h>

#include <linux/jhash.h>

#include <linux/filter.h>

#include <linux/rculist_nulls.h>

#include <uapi/linux/btf.h>

#include "percpu_freelist.h"

#include "bpf_lru_list.h"

#include "map_in_map.h"
@@ -1162,6 +1164,44 @@ static void htab_map_free(struct bpf_map *map) 
	kfree(htab);

}



static void htab_map_seq_show_elem(struct bpf_map *map, void *key,

				   struct seq_file *m)

{

	void *value;



	rcu_read_lock();



	value = htab_map_lookup_elem(map, key);

	if (!value) {

		rcu_read_unlock();

		return;

	}



	btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);

	seq_puts(m, ": ");

	btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);

	seq_puts(m, "\n");



	rcu_read_unlock();

}



static int htab_map_check_btf(const struct bpf_map *map, const struct btf *btf,

			      u32 btf_key_id, u32 btf_value_id)

{

	const struct btf_type *key_type, *value_type;

	u32 key_size, value_size;



	key_type = btf_type_id_size(btf, &btf_key_id, &key_size);

	if (!key_type || key_size != map->key_size)

		return -EINVAL;



	value_type = btf_type_id_size(btf, &btf_value_id, &value_size);

	if (!value_type || value_size != map->value_size)

		return -EINVAL;



	return 0;

}



const struct bpf_map_ops htab_map_ops = {

	.map_alloc_check = htab_map_alloc_check,

	.map_alloc = htab_map_alloc,
@@ -1171,6 +1211,8 @@ const struct bpf_map_ops htab_map_ops = { 
	.map_update_elem = htab_map_update_elem,

	.map_delete_elem = htab_map_delete_elem,

	.map_gen_lookup = htab_map_gen_lookup,

	.map_seq_show_elem = htab_map_seq_show_elem,

	.map_check_btf = htab_map_check_btf,

};



const struct bpf_map_ops htab_lru_map_ops = {
@@ -1182,6 +1224,8 @@ const struct bpf_map_ops htab_lru_map_ops = { 
	.map_update_elem = htab_lru_map_update_elem,

	.map_delete_elem = htab_lru_map_delete_elem,

	.map_gen_lookup = htab_lru_map_gen_lookup,

	.map_seq_show_elem = htab_map_seq_show_elem,

	.map_check_btf = htab_map_check_btf,

};



/* Called from eBPF program */