1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2022 Red Hat, Inc. */
3 #include <linux/bpf.h>
4 #include <linux/fs.h>
5 #include <linux/filter.h>
6 #include <linux/kernel.h>
7 #include <linux/btf_ids.h>
8
9 struct bpf_iter_seq_link_info {
10 u32 link_id;
11 };
12
13 static void *bpf_link_seq_start(struct seq_file *seq, loff_t *pos)
14 {
15 struct bpf_iter_seq_link_info *info = seq->private;
16 struct bpf_link *link;
17
18 link = bpf_link_get_curr_or_next(&info->link_id);
19 if (!link)
20 return NULL;
21
22 if (*pos == 0)
23 ++*pos;
24 return link;
25 }
26
27 static void *bpf_link_seq_next(struct seq_file *seq, void *v, loff_t *pos)
28 {
29 struct bpf_iter_seq_link_info *info = seq->private;
30
31 ++*pos;
32 ++info->link_id;
33 bpf_link_put((struct bpf_link *)v);
34 return bpf_link_get_curr_or_next(&info->link_id);
35 }
36
37 struct bpf_iter__bpf_link {
38 __bpf_md_ptr(struct bpf_iter_meta *, meta);
39 __bpf_md_ptr(struct bpf_link *, link);
40 };
41
42 DEFINE_BPF_ITER_FUNC(bpf_link, struct bpf_iter_meta *meta, struct bpf_link *link)
43
44 static int __bpf_link_seq_show(struct seq_file *seq, void *v, bool in_stop)
45 {
46 struct bpf_iter__bpf_link ctx;
47 struct bpf_iter_meta meta;
48 struct bpf_prog *prog;
49 int ret = 0;
50
51 ctx.meta = &meta;
52 ctx.link = v;
53 meta.seq = seq;
54 prog = bpf_iter_get_info(&meta, in_stop);
55 if (prog)
56 ret = bpf_iter_run_prog(prog, &ctx);
57
58 return ret;
59 }
60
61 static int bpf_link_seq_show(struct seq_file *seq, void *v)
62 {
63 return __bpf_link_seq_show(seq, v, false);
64 }
65
66 static void bpf_link_seq_stop(struct seq_file *seq, void *v)
67 {
68 if (!v)
69 (void)__bpf_link_seq_show(seq, v, true);
70 else
71 bpf_link_put((struct bpf_link *)v);
72 }
73
74 static const struct seq_operations bpf_link_seq_ops = {
75 .start = bpf_link_seq_start,
76 .next = bpf_link_seq_next,
77 .stop = bpf_link_seq_stop,
78 .show = bpf_link_seq_show,
79 };
80
81 BTF_ID_LIST(btf_bpf_link_id)
82 BTF_ID(struct, bpf_link)
83
84 static const struct bpf_iter_seq_info bpf_link_seq_info = {
85 .seq_ops = &bpf_link_seq_ops,
86 .init_seq_private = NULL,
87 .fini_seq_private = NULL,
88 .seq_priv_size = sizeof(struct bpf_iter_seq_link_info),
89 };
90
91 static struct bpf_iter_reg bpf_link_reg_info = {
92 .target = "bpf_link",
93 .ctx_arg_info_size = 1,
94 .ctx_arg_info = {
95 { offsetof(struct bpf_iter__bpf_link, link),
96 PTR_TO_BTF_ID_OR_NULL },
97 },
98 .seq_info = &bpf_link_seq_info,
99 };
100
101 static int __init bpf_link_iter_init(void)
102 {
103 bpf_link_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_link_id;
104 return bpf_iter_reg_target(&bpf_link_reg_info);
105 }
106
107 late_initcall(bpf_link_iter_init);
108
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