f0fdfefb2d
The program and map iterators work similar to seq_file-s. Once the program is pinned in bpffs it can be read with "cat" tool to print human readable output. In this case about BPF programs and maps. For example: $ cat /sys/fs/bpf/progs.debug id name attached 5 dump_bpf_map bpf_iter_bpf_map 6 dump_bpf_prog bpf_iter_bpf_prog $ cat /sys/fs/bpf/maps.debug id name max_entries 3 iterator.rodata 1 To avoid kernel build dependency on clang 10 separate bpf skeleton generation into manual "make" step and instead check-in generated .skel.h into git. Unlike 'bpftool prog show' in-kernel BTF name is used (when available) to print full name of BPF program instead of 16-byte truncated name. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200819042759.51280-3-alexei.starovoitov@gmail.com
114 lines
2.3 KiB
C
114 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Facebook */
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)
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struct seq_file;
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struct bpf_iter_meta {
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struct seq_file *seq;
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__u64 session_id;
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__u64 seq_num;
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};
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struct bpf_map {
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__u32 id;
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char name[16];
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__u32 max_entries;
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};
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struct bpf_iter__bpf_map {
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struct bpf_iter_meta *meta;
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struct bpf_map *map;
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};
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struct btf_type {
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__u32 name_off;
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};
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struct btf_header {
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__u32 str_len;
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};
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struct btf {
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const char *strings;
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struct btf_type **types;
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struct btf_header hdr;
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};
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struct bpf_prog_aux {
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__u32 id;
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char name[16];
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const char *attach_func_name;
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struct bpf_prog *linked_prog;
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struct bpf_func_info *func_info;
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struct btf *btf;
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};
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struct bpf_prog {
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struct bpf_prog_aux *aux;
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};
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struct bpf_iter__bpf_prog {
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struct bpf_iter_meta *meta;
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struct bpf_prog *prog;
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};
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#pragma clang attribute pop
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static const char *get_name(struct btf *btf, long btf_id, const char *fallback)
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{
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struct btf_type **types, *t;
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unsigned int name_off;
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const char *str;
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if (!btf)
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return fallback;
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str = btf->strings;
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types = btf->types;
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bpf_probe_read_kernel(&t, sizeof(t), types + btf_id);
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name_off = BPF_CORE_READ(t, name_off);
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if (name_off >= btf->hdr.str_len)
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return fallback;
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return str + name_off;
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}
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SEC("iter/bpf_map")
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int dump_bpf_map(struct bpf_iter__bpf_map *ctx)
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{
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struct seq_file *seq = ctx->meta->seq;
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__u64 seq_num = ctx->meta->seq_num;
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struct bpf_map *map = ctx->map;
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if (!map)
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return 0;
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if (seq_num == 0)
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BPF_SEQ_PRINTF(seq, " id name max_entries\n");
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BPF_SEQ_PRINTF(seq, "%4u %-16s%6d\n", map->id, map->name, map->max_entries);
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return 0;
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}
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SEC("iter/bpf_prog")
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int dump_bpf_prog(struct bpf_iter__bpf_prog *ctx)
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{
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struct seq_file *seq = ctx->meta->seq;
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__u64 seq_num = ctx->meta->seq_num;
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struct bpf_prog *prog = ctx->prog;
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struct bpf_prog_aux *aux;
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if (!prog)
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return 0;
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aux = prog->aux;
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if (seq_num == 0)
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BPF_SEQ_PRINTF(seq, " id name attached\n");
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BPF_SEQ_PRINTF(seq, "%4u %-16s %s %s\n", aux->id,
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get_name(aux->btf, aux->func_info[0].type_id, aux->name),
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aux->attach_func_name, aux->linked_prog->aux->name);
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return 0;
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}
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char LICENSE[] SEC("license") = "GPL";
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