Commit 6086d29d authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Add bpf_map iterator 



Implement seq_file operations to traverse all bpf_maps.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175909.2476096-1-yhs@fb.com
parent e5158d98

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -1082,6 +1082,7 @@ int generic_map_update_batch(struct bpf_map *map, 
int  generic_map_delete_batch(struct bpf_map *map,

			      const union bpf_attr *attr,

			      union bpf_attr __user *uattr);

struct bpf_map *bpf_map_get_curr_or_next(u32 *id);



extern int sysctl_unprivileged_bpf_disabled;

kernel/bpf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
obj-y := core.o

CFLAGS_core.o += $(call cc-disable-warning, override-init)



obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_iter.o

obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_iter.o map_iter.o

obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o

obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o

obj-$(CONFIG_BPF_SYSCALL) += disasm.o

kernel/bpf/map_iter.c

0 → 100644
+97 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2020 Facebook */

#include <linux/bpf.h>

#include <linux/fs.h>

#include <linux/filter.h>

#include <linux/kernel.h>



struct bpf_iter_seq_map_info {

	u32 mid;

};



static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos)

{

	struct bpf_iter_seq_map_info *info = seq->private;

	struct bpf_map *map;



	map = bpf_map_get_curr_or_next(&info->mid);

	if (!map)

		return NULL;



	++*pos;

	return map;

}



static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)

{

	struct bpf_iter_seq_map_info *info = seq->private;

	struct bpf_map *map;



	++*pos;

	++info->mid;

	bpf_map_put((struct bpf_map *)v);

	map = bpf_map_get_curr_or_next(&info->mid);

	if (!map)

		return NULL;



	return map;

}



struct bpf_iter__bpf_map {

	__bpf_md_ptr(struct bpf_iter_meta *, meta);

	__bpf_md_ptr(struct bpf_map *, map);

};



DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map)



static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop)

{

	struct bpf_iter__bpf_map ctx;

	struct bpf_iter_meta meta;

	struct bpf_prog *prog;

	int ret = 0;



	ctx.meta = &meta;

	ctx.map = v;

	meta.seq = seq;

	prog = bpf_iter_get_info(&meta, in_stop);

	if (prog)

		ret = bpf_iter_run_prog(prog, &ctx);



	return ret;

}



static int bpf_map_seq_show(struct seq_file *seq, void *v)

{

	return __bpf_map_seq_show(seq, v, false);

}



static void bpf_map_seq_stop(struct seq_file *seq, void *v)

{

	if (!v)

		(void)__bpf_map_seq_show(seq, v, true);

	else

		bpf_map_put((struct bpf_map *)v);

}



static const struct seq_operations bpf_map_seq_ops = {

	.start	= bpf_map_seq_start,

	.next	= bpf_map_seq_next,

	.stop	= bpf_map_seq_stop,

	.show	= bpf_map_seq_show,

};



static int __init bpf_map_iter_init(void)

{

	struct bpf_iter_reg reg_info = {

		.target			= "bpf_map",

		.seq_ops		= &bpf_map_seq_ops,

		.init_seq_private	= NULL,

		.fini_seq_private	= NULL,

		.seq_priv_size		= sizeof(struct bpf_iter_seq_map_info),

	};



	return bpf_iter_reg_target(&reg_info);

}



late_initcall(bpf_map_iter_init);

kernel/bpf/syscall.c

+19 −0
Original line number Diff line number Diff line
@@ -2934,6 +2934,25 @@ static int bpf_obj_get_next_id(const union bpf_attr *attr, 
	return err;

}



struct bpf_map *bpf_map_get_curr_or_next(u32 *id)

{

	struct bpf_map *map;



	spin_lock_bh(&map_idr_lock);

again:

	map = idr_get_next(&map_idr, id);

	if (map) {

		map = __bpf_map_inc_not_zero(map, false);

		if (IS_ERR(map)) {

			(*id)++;

			goto again;

		}

	}

	spin_unlock_bh(&map_idr_lock);



	return map;

}



#define BPF_PROG_GET_FD_BY_ID_LAST_FIELD prog_id



struct bpf_prog *bpf_prog_by_id(u32 id)