linux/kernel/bpf/prog_iter.c
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   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
   9struct bpf_iter_seq_prog_info {
  10        u32 prog_id;
  11};
  12
  13static 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
  27static 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
  37struct bpf_iter__bpf_prog {
  38        __bpf_md_ptr(struct bpf_iter_meta *, meta);
  39        __bpf_md_ptr(struct bpf_prog *, prog);
  40};
  41
  42DEFINE_BPF_ITER_FUNC(bpf_prog, struct bpf_iter_meta *meta, struct bpf_prog *prog)
  43
  44static 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
  61static int bpf_prog_seq_show(struct seq_file *seq, void *v)
  62{
  63        return __bpf_prog_seq_show(seq, v, false);
  64}
  65
  66static 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
  74static 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
  81BTF_ID_LIST(btf_bpf_prog_id)
  82BTF_ID(struct, bpf_prog)
  83
  84static 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
  91static 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
 101static 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
 107late_initcall(bpf_prog_iter_init);
 108