Commit a228a64f authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

bpf: Add bpf_prog iterator 



It's mostly a copy paste of commit 6086d29d ("bpf: Add bpf_map iterator")
that is use to implement bpf_seq_file opreations to traverse all bpf programs.

v1->v2: Tweak to use build time btf_id

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 3f9969f2

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -1117,6 +1117,7 @@ int generic_map_delete_batch(struct bpf_map *map, 
			      const union bpf_attr *attr,

			      union bpf_attr __user *uattr);

struct bpf_map *bpf_map_get_curr_or_next(u32 *id);

struct bpf_prog *bpf_prog_get_curr_or_next(u32 *id);



extern int sysctl_unprivileged_bpf_disabled;

kernel/bpf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
obj-y := core.o

CFLAGS_core.o += $(call cc-disable-warning, override-init)



obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_iter.o map_iter.o task_iter.o

obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_iter.o map_iter.o task_iter.o prog_iter.o

obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o

obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o

obj-$(CONFIG_BPF_SYSCALL) += disasm.o

kernel/bpf/prog_iter.c

0 → 100644
+103 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2020 Facebook */

#include <linux/bpf.h>

#include <linux/fs.h>

#include <linux/filter.h>

#include <linux/kernel.h>

#include <linux/btf_ids.h>



struct bpf_iter_seq_prog_info {

	u32 prog_id;

};



static void *bpf_prog_seq_start(struct seq_file *seq, loff_t *pos)

{

	struct bpf_iter_seq_prog_info *info = seq->private;

	struct bpf_prog *prog;



	prog = bpf_prog_get_curr_or_next(&info->prog_id);

	if (!prog)

		return NULL;



	if (*pos == 0)

		++*pos;

	return prog;

}



static void *bpf_prog_seq_next(struct seq_file *seq, void *v, loff_t *pos)

{

	struct bpf_iter_seq_prog_info *info = seq->private;



	++*pos;

	++info->prog_id;

	bpf_prog_put((struct bpf_prog *)v);

	return bpf_prog_get_curr_or_next(&info->prog_id);

}



struct bpf_iter__bpf_prog {

	__bpf_md_ptr(struct bpf_iter_meta *, meta);

	__bpf_md_ptr(struct bpf_prog *, prog);

};



DEFINE_BPF_ITER_FUNC(bpf_prog, struct bpf_iter_meta *meta, struct bpf_prog *prog)



static int __bpf_prog_seq_show(struct seq_file *seq, void *v, bool in_stop)

{

	struct bpf_iter__bpf_prog ctx;

	struct bpf_iter_meta meta;

	struct bpf_prog *prog;

	int ret = 0;



	ctx.meta = &meta;

	ctx.prog = v;

	meta.seq = seq;

	prog = bpf_iter_get_info(&meta, in_stop);

	if (prog)

		ret = bpf_iter_run_prog(prog, &ctx);



	return ret;

}



static int bpf_prog_seq_show(struct seq_file *seq, void *v)

{

	return __bpf_prog_seq_show(seq, v, false);

}



static void bpf_prog_seq_stop(struct seq_file *seq, void *v)

{

	if (!v)

		(void)__bpf_prog_seq_show(seq, v, true);

	else

		bpf_prog_put((struct bpf_prog *)v);

}



static const struct seq_operations bpf_prog_seq_ops = {

	.start	= bpf_prog_seq_start,

	.next	= bpf_prog_seq_next,

	.stop	= bpf_prog_seq_stop,

	.show	= bpf_prog_seq_show,

};



BTF_ID_LIST(btf_bpf_prog_id)

BTF_ID(struct, bpf_prog)



static struct bpf_iter_reg bpf_prog_reg_info = {

	.target			= "bpf_prog",

	.seq_ops		= &bpf_prog_seq_ops,

	.init_seq_private	= NULL,

	.fini_seq_private	= NULL,

	.seq_priv_size		= sizeof(struct bpf_iter_seq_prog_info),

	.ctx_arg_info_size	= 1,

	.ctx_arg_info		= {

		{ offsetof(struct bpf_iter__bpf_prog, prog),

		  PTR_TO_BTF_ID_OR_NULL },

	},

};



static int __init bpf_prog_iter_init(void)

{

	bpf_prog_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_prog_id;

	return bpf_iter_reg_target(&bpf_prog_reg_info);

}



late_initcall(bpf_prog_iter_init);

kernel/bpf/syscall.c

+19 −0
Original line number Diff line number Diff line
@@ -3044,6 +3044,25 @@ struct bpf_map *bpf_map_get_curr_or_next(u32 *id) 
	return map;

}



struct bpf_prog *bpf_prog_get_curr_or_next(u32 *id)

{

	struct bpf_prog *prog;



	spin_lock_bh(&prog_idr_lock);

again:

	prog = idr_get_next(&prog_idr, id);

	if (prog) {

		prog = bpf_prog_inc_not_zero(prog);

		if (IS_ERR(prog)) {

			(*id)++;

			goto again;

		}

	}

	spin_unlock_bh(&prog_idr_lock);



	return prog;

}



#define BPF_PROG_GET_FD_BY_ID_LAST_FIELD prog_id



struct bpf_prog *bpf_prog_by_id(u32 id)