From 9a1126b63190e2541dd5d643f4bfeb5a7f493729 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Mon, 10 Dec 2018 15:43:01 -0800 Subject: bpf: add bpffs pretty print for cgroup local storage maps Implement bpffs pretty printing for cgroup local storage maps (both shared and per-cpu). Output example (captured for tools/testing/selftests/bpf/netcnt_prog.c): Shared: $ cat /sys/fs/bpf/map_2 # WARNING!! The output is for debug purpose only # WARNING!! The output format will change {4294968594,1}: {9999,1039896} Per-cpu: $ cat /sys/fs/bpf/map_1 # WARNING!! The output is for debug purpose only # WARNING!! The output format will change {4294968594,1}: { cpu0: {0,0,0,0,0} cpu1: {0,0,0,0,0} cpu2: {1,104,0,0,0} cpu3: {0,0,0,0,0} } Signed-off-by: Roman Gushchin Cc: Alexei Starovoitov Cc: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov --- kernel/bpf/btf.c | 22 +++++++++++ kernel/bpf/local_storage.c | 93 +++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 114 insertions(+), 1 deletion(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index bf34933cc413..1545ddfb6fa5 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -514,6 +514,28 @@ static bool btf_type_int_is_regular(const struct btf_type *t) return true; } +/* + * Check that given type is a regular int and has the expected size. + */ +bool btf_type_is_reg_int(const struct btf_type *t, u32 expected_size) +{ + u8 nr_bits, nr_bytes; + u32 int_data; + + if (!btf_type_is_int(t)) + return false; + + int_data = btf_type_int(t); + nr_bits = BTF_INT_BITS(int_data); + nr_bytes = BITS_ROUNDUP_BYTES(nr_bits); + if (BITS_PER_BYTE_MASKED(nr_bits) || + BTF_INT_OFFSET(int_data) || + nr_bytes != expected_size) + return false; + + return true; +} + __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log, const char *fmt, ...) { diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c index b65017dead44..5eca03da0989 100644 --- a/kernel/bpf/local_storage.c +++ b/kernel/bpf/local_storage.c @@ -1,11 +1,13 @@ //SPDX-License-Identifier: GPL-2.0 #include #include +#include #include #include #include #include #include +#include DEFINE_PER_CPU(struct bpf_cgroup_storage*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]); @@ -308,6 +310,94 @@ static int cgroup_storage_delete_elem(struct bpf_map *map, void *key) return -EINVAL; } +static int cgroup_storage_check_btf(const struct bpf_map *map, + const struct btf *btf, + const struct btf_type *key_type, + const struct btf_type *value_type) +{ + const struct btf_type *t; + struct btf_member *m; + u32 id, size; + + /* Key is expected to be of struct bpf_cgroup_storage_key type, + * which is: + * struct bpf_cgroup_storage_key { + * __u64 cgroup_inode_id; + * __u32 attach_type; + * }; + */ + + /* + * Key_type must be a structure with two fields. + */ + if (BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT || + BTF_INFO_VLEN(key_type->info) != 2) + return -EINVAL; + + /* + * The first field must be a 64 bit integer at 0 offset. + */ + m = (struct btf_member *)(key_type + 1); + if (m->offset) + return -EINVAL; + id = m->type; + t = btf_type_id_size(btf, &id, NULL); + size = FIELD_SIZEOF(struct bpf_cgroup_storage_key, cgroup_inode_id); + if (!t || !btf_type_is_reg_int(t, size)) + return -EINVAL; + + /* + * The second field must be a 32 bit integer at 64 bit offset. + */ + m++; + if (m->offset != offsetof(struct bpf_cgroup_storage_key, attach_type) * + BITS_PER_BYTE) + return -EINVAL; + id = m->type; + t = btf_type_id_size(btf, &id, NULL); + size = FIELD_SIZEOF(struct bpf_cgroup_storage_key, attach_type); + if (!t || !btf_type_is_reg_int(t, size)) + return -EINVAL; + + return 0; +} + +static void cgroup_storage_seq_show_elem(struct bpf_map *map, void *_key, + struct seq_file *m) +{ + enum bpf_cgroup_storage_type stype = cgroup_storage_type(map); + struct bpf_cgroup_storage_key *key = _key; + struct bpf_cgroup_storage *storage; + int cpu; + + rcu_read_lock(); + storage = cgroup_storage_lookup(map_to_storage(map), key, false); + if (!storage) { + rcu_read_unlock(); + return; + } + + btf_type_seq_show(map->btf, map->btf_key_type_id, key, m); + stype = cgroup_storage_type(map); + if (stype == BPF_CGROUP_STORAGE_SHARED) { + seq_puts(m, ": "); + btf_type_seq_show(map->btf, map->btf_value_type_id, + &READ_ONCE(storage->buf)->data[0], m); + seq_puts(m, "\n"); + } else { + seq_puts(m, ": {\n"); + for_each_possible_cpu(cpu) { + seq_printf(m, "\tcpu%d: ", cpu); + btf_type_seq_show(map->btf, map->btf_value_type_id, + per_cpu_ptr(storage->percpu_buf, cpu), + m); + seq_puts(m, "\n"); + } + seq_puts(m, "}\n"); + } + rcu_read_unlock(); +} + const struct bpf_map_ops cgroup_storage_map_ops = { .map_alloc = cgroup_storage_map_alloc, .map_free = cgroup_storage_map_free, @@ -315,7 +405,8 @@ const struct bpf_map_ops cgroup_storage_map_ops = { .map_lookup_elem = cgroup_storage_lookup_elem, .map_update_elem = cgroup_storage_update_elem, .map_delete_elem = cgroup_storage_delete_elem, - .map_check_btf = map_check_no_btf, + .map_check_btf = cgroup_storage_check_btf, + .map_seq_show_elem = cgroup_storage_seq_show_elem, }; int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map) -- cgit v1.2.3