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bpf: Add bpf_prog iterator

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It's mostly a copy paste of commit 6086d29def ("bpf: Add bpf_map iterator")
that is use to implement bpf_seq_file opreations to traverse all bpf programs.

v1->v2: Tweak to use build time btf_id

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Alexei Starovoitov
2020-07-01 18:10:18 -07:00
parent 3f9969f2c0
commit a228a64fc1
4 changed files with 124 additions and 1 deletions
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103
kernel/bpf/prog_iter.c Normal file
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@@ -0,0 +1,103 @@
// 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>
#include <linux/btf_ids.h>
struct bpf_iter_seq_prog_info {
u32 prog_id;
};
static void *bpf_prog_seq_start(struct seq_file *seq, loff_t *pos)
{
struct bpf_iter_seq_prog_info *info = seq->private;
struct bpf_prog *prog;
prog = bpf_prog_get_curr_or_next(&info->prog_id);
if (!prog)
return NULL;
if (*pos == 0)
++*pos;
return prog;
}
static void *bpf_prog_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct bpf_iter_seq_prog_info *info = seq->private;
++*pos;
++info->prog_id;
bpf_prog_put((struct bpf_prog *)v);
return bpf_prog_get_curr_or_next(&info->prog_id);
}
struct bpf_iter__bpf_prog {
__bpf_md_ptr(struct bpf_iter_meta *, meta);
__bpf_md_ptr(struct bpf_prog *, prog);
};
DEFINE_BPF_ITER_FUNC(bpf_prog, struct bpf_iter_meta *meta, struct bpf_prog *prog)
static int __bpf_prog_seq_show(struct seq_file *seq, void *v, bool in_stop)
{
struct bpf_iter__bpf_prog ctx;
struct bpf_iter_meta meta;
struct bpf_prog *prog;
int ret = 0;
ctx.meta = &meta;
ctx.prog = 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_prog_seq_show(struct seq_file *seq, void *v)
{
return __bpf_prog_seq_show(seq, v, false);
}
static void bpf_prog_seq_stop(struct seq_file *seq, void *v)
{
if (!v)
(void)__bpf_prog_seq_show(seq, v, true);
else
bpf_prog_put((struct bpf_prog *)v);
}
static const struct seq_operations bpf_prog_seq_ops = {
.start = bpf_prog_seq_start,
.next = bpf_prog_seq_next,
.stop = bpf_prog_seq_stop,
.show = bpf_prog_seq_show,
};
BTF_ID_LIST(btf_bpf_prog_id)
BTF_ID(struct, bpf_prog)
static struct bpf_iter_reg bpf_prog_reg_info = {
.target = "bpf_prog",
.seq_ops = &bpf_prog_seq_ops,
.init_seq_private = NULL,
.fini_seq_private = NULL,
.seq_priv_size = sizeof(struct bpf_iter_seq_prog_info),
.ctx_arg_info_size = 1,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__bpf_prog, prog),
PTR_TO_BTF_ID_OR_NULL },
},
};
static int __init bpf_prog_iter_init(void)
{
bpf_prog_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_prog_id;
return bpf_iter_reg_target(&bpf_prog_reg_info);
}
late_initcall(bpf_prog_iter_init);