mirror of
https://github.com/torvalds/linux.git
synced 2024-12-11 13:41:55 +00:00
9f88361273
Implement bpf_link iterator to traverse links via bpf_seq_file
operations. The changeset is mostly shamelessly copied from
commit a228a64fc1 ("bpf: Add bpf_prog iterator")
Signed-off-by: Dmitrii Dolgov <9erthalion6@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220510155233.9815-2-9erthalion6@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
108 lines
2.4 KiB
C
108 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/* Copyright (c) 2022 Red Hat, Inc. */
|
|
#include <linux/bpf.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/filter.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/btf_ids.h>
|
|
|
|
struct bpf_iter_seq_link_info {
|
|
u32 link_id;
|
|
};
|
|
|
|
static void *bpf_link_seq_start(struct seq_file *seq, loff_t *pos)
|
|
{
|
|
struct bpf_iter_seq_link_info *info = seq->private;
|
|
struct bpf_link *link;
|
|
|
|
link = bpf_link_get_curr_or_next(&info->link_id);
|
|
if (!link)
|
|
return NULL;
|
|
|
|
if (*pos == 0)
|
|
++*pos;
|
|
return link;
|
|
}
|
|
|
|
static void *bpf_link_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
|
{
|
|
struct bpf_iter_seq_link_info *info = seq->private;
|
|
|
|
++*pos;
|
|
++info->link_id;
|
|
bpf_link_put((struct bpf_link *)v);
|
|
return bpf_link_get_curr_or_next(&info->link_id);
|
|
}
|
|
|
|
struct bpf_iter__bpf_link {
|
|
__bpf_md_ptr(struct bpf_iter_meta *, meta);
|
|
__bpf_md_ptr(struct bpf_link *, link);
|
|
};
|
|
|
|
DEFINE_BPF_ITER_FUNC(bpf_link, struct bpf_iter_meta *meta, struct bpf_link *link)
|
|
|
|
static int __bpf_link_seq_show(struct seq_file *seq, void *v, bool in_stop)
|
|
{
|
|
struct bpf_iter__bpf_link ctx;
|
|
struct bpf_iter_meta meta;
|
|
struct bpf_prog *prog;
|
|
int ret = 0;
|
|
|
|
ctx.meta = &meta;
|
|
ctx.link = 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_link_seq_show(struct seq_file *seq, void *v)
|
|
{
|
|
return __bpf_link_seq_show(seq, v, false);
|
|
}
|
|
|
|
static void bpf_link_seq_stop(struct seq_file *seq, void *v)
|
|
{
|
|
if (!v)
|
|
(void)__bpf_link_seq_show(seq, v, true);
|
|
else
|
|
bpf_link_put((struct bpf_link *)v);
|
|
}
|
|
|
|
static const struct seq_operations bpf_link_seq_ops = {
|
|
.start = bpf_link_seq_start,
|
|
.next = bpf_link_seq_next,
|
|
.stop = bpf_link_seq_stop,
|
|
.show = bpf_link_seq_show,
|
|
};
|
|
|
|
BTF_ID_LIST(btf_bpf_link_id)
|
|
BTF_ID(struct, bpf_link)
|
|
|
|
static const struct bpf_iter_seq_info bpf_link_seq_info = {
|
|
.seq_ops = &bpf_link_seq_ops,
|
|
.init_seq_private = NULL,
|
|
.fini_seq_private = NULL,
|
|
.seq_priv_size = sizeof(struct bpf_iter_seq_link_info),
|
|
};
|
|
|
|
static struct bpf_iter_reg bpf_link_reg_info = {
|
|
.target = "bpf_link",
|
|
.ctx_arg_info_size = 1,
|
|
.ctx_arg_info = {
|
|
{ offsetof(struct bpf_iter__bpf_link, link),
|
|
PTR_TO_BTF_ID_OR_NULL },
|
|
},
|
|
.seq_info = &bpf_link_seq_info,
|
|
};
|
|
|
|
static int __init bpf_link_iter_init(void)
|
|
{
|
|
bpf_link_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_link_id;
|
|
return bpf_iter_reg_target(&bpf_link_reg_info);
|
|
}
|
|
|
|
late_initcall(bpf_link_iter_init);
|