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