kernel/bpf/prog_iter.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2020 Facebook */
   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_prog_info {
  10         u32 prog_id;
  11 };
  12
  13 static void *bpf_prog_seq_start(struct seq_file *seq, loff_t *pos)
  14 {
  15         struct bpf_iter_seq_prog_info *info = seq->private;
  16         struct bpf_prog *prog;
  17
  18         prog = bpf_prog_get_curr_or_next(&info->prog_id);
  19         if (!prog)
  20                 return NULL;
  21
  22         if (*pos == 0)
  23                 ++*pos;
  24         return prog;
  25 }
  26
  27 static void *bpf_prog_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  28 {
  29         struct bpf_iter_seq_prog_info *info = seq->private;
  30
  31         ++*pos;
  32         ++info->prog_id;
  33         bpf_prog_put((struct bpf_prog *)v);
  34         return bpf_prog_get_curr_or_next(&info->prog_id);
  35 }
  36
  37 struct bpf_iter__bpf_prog {
  38         __bpf_md_ptr(struct bpf_iter_meta *, meta);
  39         __bpf_md_ptr(struct bpf_prog *, prog);
  40 };
  41
  42 DEFINE_BPF_ITER_FUNC(bpf_prog, struct bpf_iter_meta *meta, struct bpf_prog *prog)
  43
  44 static int __bpf_prog_seq_show(struct seq_file *seq, void *v, bool in_stop)
  45 {
  46         struct bpf_iter__bpf_prog ctx;
  47         struct bpf_iter_meta meta;
  48         struct bpf_prog *prog;
  49         int ret = 0;
  50
  51         ctx.meta = &meta;
  52         ctx.prog = 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_prog_seq_show(struct seq_file *seq, void *v)
  62 {
  63         return __bpf_prog_seq_show(seq, v, false);
  64 }
  65
  66 static void bpf_prog_seq_stop(struct seq_file *seq, void *v)
  67 {
  68         if (!v)
  69                 (void)__bpf_prog_seq_show(seq, v, true);
  70         else
  71                 bpf_prog_put((struct bpf_prog *)v);
  72 }
  73
  74 static const struct seq_operations bpf_prog_seq_ops = {
  75         .start  = bpf_prog_seq_start,
  76         .next   = bpf_prog_seq_next,
  77         .stop   = bpf_prog_seq_stop,
  78         .show   = bpf_prog_seq_show,
  79 };
  80
  81 BTF_ID_LIST(btf_bpf_prog_id)
  82 BTF_ID(struct, bpf_prog)
  83
  84 static const struct bpf_iter_seq_info bpf_prog_seq_info = {
  85         .seq_ops                = &bpf_prog_seq_ops,
  86         .init_seq_private       = NULL,
  87         .fini_seq_private       = NULL,
  88         .seq_priv_size          = sizeof(struct bpf_iter_seq_prog_info),
  89 };
  90
  91 static struct bpf_iter_reg bpf_prog_reg_info = {
  92         .target                 = "bpf_prog",
  93         .ctx_arg_info_size      = 1,
  94         .ctx_arg_info           = {
  95                 { offsetof(struct bpf_iter__bpf_prog, prog),
  96                   PTR_TO_BTF_ID_OR_NULL },
  97         },
  98         .seq_info               = &bpf_prog_seq_info,
  99 };
 100
 101 static int __init bpf_prog_iter_init(void)
 102 {
 103         bpf_prog_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_prog_id;
 104         return bpf_iter_reg_target(&bpf_prog_reg_info);
 105 }
 106
 107 late_initcall(bpf_prog_iter_init);