From a228a64fc1e4428e2b96dc68e9ad3c447095c9e7 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 1 Jul 2020 18:10:18 -0700 Subject: [PATCH] bpf: Add bpf_prog iterator It's mostly a copy paste of commit 6086d29def80 ("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: Alexei Starovoitov Acked-by: Yonghong Song Acked-by: Daniel Borkmann --- include/linux/bpf.h | 1 + kernel/bpf/Makefile | 2 +- kernel/bpf/prog_iter.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 19 +++++++++ 4 files changed, 124 insertions(+), 1 deletion(-) create mode 100644 kernel/bpf/prog_iter.c diff --git a/include/linux/bpf.h b/include/linux/bpf.h index bae557ff2da8..72221aea1c60 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -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; diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 1131a921e1a6..e6eb9c0402da 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -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 diff --git a/kernel/bpf/prog_iter.c b/kernel/bpf/prog_iter.c new file mode 100644 index 000000000000..6541b577d69f --- /dev/null +++ b/kernel/bpf/prog_iter.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2020 Facebook */ +#include +#include +#include +#include +#include + +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); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index d07417d17712..ee290b1f2d9e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3044,6 +3044,25 @@ again: 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) -- 2.11.0