kernel/bpf/map_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
   8 struct bpf_iter_seq_map_info {
   9         u32 mid;
  10 };
  11
  12 static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos)
  13 {
  14         struct bpf_iter_seq_map_info *info = seq->private;
  15         struct bpf_map *map;
  16
  17         map = bpf_map_get_curr_or_next(&info->mid);
  18         if (!map)
  19                 return NULL;
  20
  21         ++*pos;
  22         return map;
  23 }
  24
  25 static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  26 {
  27         struct bpf_iter_seq_map_info *info = seq->private;
  28         struct bpf_map *map;
  29
  30         ++*pos;
  31         ++info->mid;
  32         bpf_map_put((struct bpf_map *)v);
  33         map = bpf_map_get_curr_or_next(&info->mid);
  34         if (!map)
  35                 return NULL;
  36
  37         return map;
  38 }
  39
  40 struct bpf_iter__bpf_map {
  41         __bpf_md_ptr(struct bpf_iter_meta *, meta);
  42         __bpf_md_ptr(struct bpf_map *, map);
  43 };
  44
  45 DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map)
  46
  47 static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop)
  48 {
  49         struct bpf_iter__bpf_map ctx;
  50         struct bpf_iter_meta meta;
  51         struct bpf_prog *prog;
  52         int ret = 0;
  53
  54         ctx.meta = &meta;
  55         ctx.map = v;
  56         meta.seq = seq;
  57         prog = bpf_iter_get_info(&meta, in_stop);
  58         if (prog)
  59                 ret = bpf_iter_run_prog(prog, &ctx);
  60
  61         return ret;
  62 }
  63
  64 static int bpf_map_seq_show(struct seq_file *seq, void *v)
  65 {
  66         return __bpf_map_seq_show(seq, v, false);
  67 }
  68
  69 static void bpf_map_seq_stop(struct seq_file *seq, void *v)
  70 {
  71         if (!v)
  72                 (void)__bpf_map_seq_show(seq, v, true);
  73         else
  74                 bpf_map_put((struct bpf_map *)v);
  75 }
  76
  77 static const struct seq_operations bpf_map_seq_ops = {
  78         .start  = bpf_map_seq_start,
  79         .next   = bpf_map_seq_next,
  80         .stop   = bpf_map_seq_stop,
  81         .show   = bpf_map_seq_show,
  82 };
  83
  84 static const struct bpf_iter_reg bpf_map_reg_info = {
  85         .target                 = "bpf_map",
  86         .seq_ops                = &bpf_map_seq_ops,
  87         .init_seq_private       = NULL,
  88         .fini_seq_private       = NULL,
  89         .seq_priv_size          = sizeof(struct bpf_iter_seq_map_info),
  90         .ctx_arg_info_size      = 1,
  91         .ctx_arg_info           = {
  92                 { offsetof(struct bpf_iter__bpf_map, map),
  93                   PTR_TO_BTF_ID_OR_NULL },
  94         },
  95 };
  96
  97 static int __init bpf_map_iter_init(void)
  98 {
  99         return bpf_iter_reg_target(&bpf_map_reg_info);
 100 }
 101
 102 late_initcall(bpf_map_iter_init);