libbpf: Move feature detection code into its own file
It's quite a lot of well isolated code, so it seems like a good candidate to move it out of libbpf.c to reduce its size. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-24-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko
Alexei Starovoitov
parent
d6dd1d4936
commit
05f9cdd55d
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@ -1,4 +1,4 @@
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libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o \
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netlink.o bpf_prog_linfo.o libbpf_probes.o hashmap.o \
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btf_dump.o ringbuf.o strset.o linker.o gen_loader.o relo_core.o \
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usdt.o zip.o elf.o
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usdt.o zip.o elf.o features.o
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@ -11,8 +11,6 @@
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#include "libbpf_internal.h"
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#include "str_error.h"
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#define STRERR_BUFSIZE 128
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/* A SHT_GNU_versym section holds 16-bit words. This bit is set if
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* the symbol is hidden and can only be seen when referenced using an
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* explicit version number. This is a GNU extension.
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@ -0,0 +1,463 @@
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// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#include <linux/kernel.h>
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#include <linux/filter.h>
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#include "bpf.h"
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#include "libbpf.h"
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#include "libbpf_common.h"
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#include "libbpf_internal.h"
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#include "str_error.h"
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static inline __u64 ptr_to_u64(const void *ptr)
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{
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return (__u64)(unsigned long)ptr;
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}
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int probe_fd(int fd)
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{
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if (fd >= 0)
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close(fd);
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return fd >= 0;
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}
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static int probe_kern_prog_name(void)
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{
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const size_t attr_sz = offsetofend(union bpf_attr, prog_name);
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struct bpf_insn insns[] = {
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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union bpf_attr attr;
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int ret;
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memset(&attr, 0, attr_sz);
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attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
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attr.license = ptr_to_u64("GPL");
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attr.insns = ptr_to_u64(insns);
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attr.insn_cnt = (__u32)ARRAY_SIZE(insns);
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libbpf_strlcpy(attr.prog_name, "libbpf_nametest", sizeof(attr.prog_name));
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/* make sure loading with name works */
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ret = sys_bpf_prog_load(&attr, attr_sz, PROG_LOAD_ATTEMPTS);
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return probe_fd(ret);
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}
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static int probe_kern_global_data(void)
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{
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char *cp, errmsg[STRERR_BUFSIZE];
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struct bpf_insn insns[] = {
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BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
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BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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int ret, map, insn_cnt = ARRAY_SIZE(insns);
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map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_global", sizeof(int), 32, 1, NULL);
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if (map < 0) {
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ret = -errno;
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cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
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pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
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__func__, cp, -ret);
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return ret;
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}
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insns[0].imm = map;
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ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL);
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close(map);
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return probe_fd(ret);
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}
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static int probe_kern_btf(void)
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{
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static const char strs[] = "\0int";
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__u32 types[] = {
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/* int */
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BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
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};
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return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
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strs, sizeof(strs)));
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}
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static int probe_kern_btf_func(void)
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{
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static const char strs[] = "\0int\0x\0a";
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/* void x(int a) {} */
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__u32 types[] = {
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/* int */
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BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
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/* FUNC_PROTO */ /* [2] */
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BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
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BTF_PARAM_ENC(7, 1),
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/* FUNC x */ /* [3] */
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BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
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};
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return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
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strs, sizeof(strs)));
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}
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static int probe_kern_btf_func_global(void)
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{
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static const char strs[] = "\0int\0x\0a";
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/* static void x(int a) {} */
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__u32 types[] = {
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/* int */
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BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
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/* FUNC_PROTO */ /* [2] */
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BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
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BTF_PARAM_ENC(7, 1),
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/* FUNC x BTF_FUNC_GLOBAL */ /* [3] */
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BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2),
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};
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return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
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strs, sizeof(strs)));
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}
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static int probe_kern_btf_datasec(void)
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{
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static const char strs[] = "\0x\0.data";
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/* static int a; */
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__u32 types[] = {
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/* int */
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BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
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/* VAR x */ /* [2] */
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BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
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BTF_VAR_STATIC,
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/* DATASEC val */ /* [3] */
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BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
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BTF_VAR_SECINFO_ENC(2, 0, 4),
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};
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return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
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strs, sizeof(strs)));
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}
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static int probe_kern_btf_float(void)
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{
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static const char strs[] = "\0float";
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__u32 types[] = {
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/* float */
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BTF_TYPE_FLOAT_ENC(1, 4),
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};
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return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
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strs, sizeof(strs)));
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}
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static int probe_kern_btf_decl_tag(void)
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{
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static const char strs[] = "\0tag";
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__u32 types[] = {
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/* int */
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BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
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/* VAR x */ /* [2] */
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BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
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BTF_VAR_STATIC,
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/* attr */
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BTF_TYPE_DECL_TAG_ENC(1, 2, -1),
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};
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return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
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strs, sizeof(strs)));
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}
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static int probe_kern_btf_type_tag(void)
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{
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static const char strs[] = "\0tag";
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__u32 types[] = {
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/* int */
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BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
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/* attr */
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BTF_TYPE_TYPE_TAG_ENC(1, 1), /* [2] */
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/* ptr */
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BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2), /* [3] */
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};
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return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
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strs, sizeof(strs)));
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}
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static int probe_kern_array_mmap(void)
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{
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LIBBPF_OPTS(bpf_map_create_opts, opts, .map_flags = BPF_F_MMAPABLE);
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int fd;
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fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_mmap", sizeof(int), sizeof(int), 1, &opts);
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return probe_fd(fd);
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}
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static int probe_kern_exp_attach_type(void)
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{
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LIBBPF_OPTS(bpf_prog_load_opts, opts, .expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE);
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struct bpf_insn insns[] = {
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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int fd, insn_cnt = ARRAY_SIZE(insns);
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/* use any valid combination of program type and (optional)
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* non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS)
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* to see if kernel supports expected_attach_type field for
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* BPF_PROG_LOAD command
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*/
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fd = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SOCK, NULL, "GPL", insns, insn_cnt, &opts);
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return probe_fd(fd);
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}
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static int probe_kern_probe_read_kernel(void)
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{
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struct bpf_insn insns[] = {
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BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), /* r1 = r10 (fp) */
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BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), /* r1 += -8 */
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BPF_MOV64_IMM(BPF_REG_2, 8), /* r2 = 8 */
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BPF_MOV64_IMM(BPF_REG_3, 0), /* r3 = 0 */
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel),
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BPF_EXIT_INSN(),
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};
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int fd, insn_cnt = ARRAY_SIZE(insns);
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fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL);
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return probe_fd(fd);
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}
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static int probe_prog_bind_map(void)
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{
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char *cp, errmsg[STRERR_BUFSIZE];
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struct bpf_insn insns[] = {
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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int ret, map, prog, insn_cnt = ARRAY_SIZE(insns);
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map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_det_bind", sizeof(int), 32, 1, NULL);
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if (map < 0) {
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ret = -errno;
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cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
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pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
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__func__, cp, -ret);
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return ret;
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}
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prog = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL);
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if (prog < 0) {
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close(map);
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return 0;
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}
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ret = bpf_prog_bind_map(prog, map, NULL);
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close(map);
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close(prog);
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return ret >= 0;
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}
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static int probe_module_btf(void)
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{
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static const char strs[] = "\0int";
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__u32 types[] = {
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/* int */
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BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
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};
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struct bpf_btf_info info;
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__u32 len = sizeof(info);
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char name[16];
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int fd, err;
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fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs));
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if (fd < 0)
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return 0; /* BTF not supported at all */
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memset(&info, 0, sizeof(info));
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info.name = ptr_to_u64(name);
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info.name_len = sizeof(name);
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/* check that BPF_OBJ_GET_INFO_BY_FD supports specifying name pointer;
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* kernel's module BTF support coincides with support for
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* name/name_len fields in struct bpf_btf_info.
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*/
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err = bpf_btf_get_info_by_fd(fd, &info, &len);
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close(fd);
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return !err;
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}
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static int probe_perf_link(void)
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{
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struct bpf_insn insns[] = {
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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int prog_fd, link_fd, err;
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prog_fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL",
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insns, ARRAY_SIZE(insns), NULL);
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if (prog_fd < 0)
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return -errno;
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/* use invalid perf_event FD to get EBADF, if link is supported;
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* otherwise EINVAL should be returned
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*/
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link_fd = bpf_link_create(prog_fd, -1, BPF_PERF_EVENT, NULL);
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err = -errno; /* close() can clobber errno */
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if (link_fd >= 0)
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close(link_fd);
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close(prog_fd);
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return link_fd < 0 && err == -EBADF;
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}
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static int probe_uprobe_multi_link(void)
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{
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LIBBPF_OPTS(bpf_prog_load_opts, load_opts,
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.expected_attach_type = BPF_TRACE_UPROBE_MULTI,
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);
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LIBBPF_OPTS(bpf_link_create_opts, link_opts);
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struct bpf_insn insns[] = {
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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int prog_fd, link_fd, err;
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unsigned long offset = 0;
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prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL",
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insns, ARRAY_SIZE(insns), &load_opts);
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if (prog_fd < 0)
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return -errno;
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/* Creating uprobe in '/' binary should fail with -EBADF. */
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link_opts.uprobe_multi.path = "/";
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link_opts.uprobe_multi.offsets = &offset;
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link_opts.uprobe_multi.cnt = 1;
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link_fd = bpf_link_create(prog_fd, -1, BPF_TRACE_UPROBE_MULTI, &link_opts);
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err = -errno; /* close() can clobber errno */
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if (link_fd >= 0)
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close(link_fd);
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close(prog_fd);
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return link_fd < 0 && err == -EBADF;
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}
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static int probe_kern_bpf_cookie(void)
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{
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struct bpf_insn insns[] = {
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_attach_cookie),
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BPF_EXIT_INSN(),
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};
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int ret, insn_cnt = ARRAY_SIZE(insns);
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ret = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", insns, insn_cnt, NULL);
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return probe_fd(ret);
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}
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static int probe_kern_btf_enum64(void)
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{
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static const char strs[] = "\0enum64";
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__u32 types[] = {
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BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_ENUM64, 0, 0), 8),
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};
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return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
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strs, sizeof(strs)));
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}
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typedef int (*feature_probe_fn)(void);
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static struct kern_feature_cache feature_cache;
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static struct kern_feature_desc {
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const char *desc;
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feature_probe_fn probe;
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} feature_probes[__FEAT_CNT] = {
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[FEAT_PROG_NAME] = {
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"BPF program name", probe_kern_prog_name,
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},
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[FEAT_GLOBAL_DATA] = {
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"global variables", probe_kern_global_data,
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},
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[FEAT_BTF] = {
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"minimal BTF", probe_kern_btf,
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},
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[FEAT_BTF_FUNC] = {
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"BTF functions", probe_kern_btf_func,
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},
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[FEAT_BTF_GLOBAL_FUNC] = {
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"BTF global function", probe_kern_btf_func_global,
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},
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[FEAT_BTF_DATASEC] = {
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"BTF data section and variable", probe_kern_btf_datasec,
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},
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[FEAT_ARRAY_MMAP] = {
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"ARRAY map mmap()", probe_kern_array_mmap,
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},
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[FEAT_EXP_ATTACH_TYPE] = {
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"BPF_PROG_LOAD expected_attach_type attribute",
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probe_kern_exp_attach_type,
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},
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[FEAT_PROBE_READ_KERN] = {
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"bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel,
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},
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[FEAT_PROG_BIND_MAP] = {
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"BPF_PROG_BIND_MAP support", probe_prog_bind_map,
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},
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[FEAT_MODULE_BTF] = {
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"module BTF support", probe_module_btf,
|
||||
},
|
||||
[FEAT_BTF_FLOAT] = {
|
||||
"BTF_KIND_FLOAT support", probe_kern_btf_float,
|
||||
},
|
||||
[FEAT_PERF_LINK] = {
|
||||
"BPF perf link support", probe_perf_link,
|
||||
},
|
||||
[FEAT_BTF_DECL_TAG] = {
|
||||
"BTF_KIND_DECL_TAG support", probe_kern_btf_decl_tag,
|
||||
},
|
||||
[FEAT_BTF_TYPE_TAG] = {
|
||||
"BTF_KIND_TYPE_TAG support", probe_kern_btf_type_tag,
|
||||
},
|
||||
[FEAT_MEMCG_ACCOUNT] = {
|
||||
"memcg-based memory accounting", probe_memcg_account,
|
||||
},
|
||||
[FEAT_BPF_COOKIE] = {
|
||||
"BPF cookie support", probe_kern_bpf_cookie,
|
||||
},
|
||||
[FEAT_BTF_ENUM64] = {
|
||||
"BTF_KIND_ENUM64 support", probe_kern_btf_enum64,
|
||||
},
|
||||
[FEAT_SYSCALL_WRAPPER] = {
|
||||
"Kernel using syscall wrapper", probe_kern_syscall_wrapper,
|
||||
},
|
||||
[FEAT_UPROBE_MULTI_LINK] = {
|
||||
"BPF multi-uprobe link support", probe_uprobe_multi_link,
|
||||
},
|
||||
};
|
||||
|
||||
bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id)
|
||||
{
|
||||
struct kern_feature_desc *feat = &feature_probes[feat_id];
|
||||
int ret;
|
||||
|
||||
/* assume global feature cache, unless custom one is provided */
|
||||
if (!cache)
|
||||
cache = &feature_cache;
|
||||
|
||||
if (READ_ONCE(cache->res[feat_id]) == FEAT_UNKNOWN) {
|
||||
ret = feat->probe();
|
||||
if (ret > 0) {
|
||||
WRITE_ONCE(cache->res[feat_id], FEAT_SUPPORTED);
|
||||
} else if (ret == 0) {
|
||||
WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
|
||||
} else {
|
||||
pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret);
|
||||
WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
|
||||
}
|
||||
}
|
||||
|
||||
return READ_ONCE(cache->res[feat_id]) == FEAT_SUPPORTED;
|
||||
}
|
||||
|
|
@ -4596,467 +4596,6 @@ bpf_object__probe_loading(struct bpf_object *obj)
|
|||
return 0;
|
||||
}
|
||||
|
||||
static int probe_fd(int fd)
|
||||
{
|
||||
if (fd >= 0)
|
||||
close(fd);
|
||||
return fd >= 0;
|
||||
}
|
||||
|
||||
static int probe_kern_prog_name(void)
|
||||
{
|
||||
const size_t attr_sz = offsetofend(union bpf_attr, prog_name);
|
||||
struct bpf_insn insns[] = {
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
};
|
||||
union bpf_attr attr;
|
||||
int ret;
|
||||
|
||||
memset(&attr, 0, attr_sz);
|
||||
attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
|
||||
attr.license = ptr_to_u64("GPL");
|
||||
attr.insns = ptr_to_u64(insns);
|
||||
attr.insn_cnt = (__u32)ARRAY_SIZE(insns);
|
||||
libbpf_strlcpy(attr.prog_name, "libbpf_nametest", sizeof(attr.prog_name));
|
||||
|
||||
/* make sure loading with name works */
|
||||
ret = sys_bpf_prog_load(&attr, attr_sz, PROG_LOAD_ATTEMPTS);
|
||||
return probe_fd(ret);
|
||||
}
|
||||
|
||||
static int probe_kern_global_data(void)
|
||||
{
|
||||
char *cp, errmsg[STRERR_BUFSIZE];
|
||||
struct bpf_insn insns[] = {
|
||||
BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
};
|
||||
int ret, map, insn_cnt = ARRAY_SIZE(insns);
|
||||
|
||||
map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_global", sizeof(int), 32, 1, NULL);
|
||||
if (map < 0) {
|
||||
ret = -errno;
|
||||
cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
|
||||
pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
|
||||
__func__, cp, -ret);
|
||||
return ret;
|
||||
}
|
||||
|
||||
insns[0].imm = map;
|
||||
|
||||
ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL);
|
||||
close(map);
|
||||
return probe_fd(ret);
|
||||
}
|
||||
|
||||
static int probe_kern_btf(void)
|
||||
{
|
||||
static const char strs[] = "\0int";
|
||||
__u32 types[] = {
|
||||
/* int */
|
||||
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
|
||||
};
|
||||
|
||||
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
|
||||
strs, sizeof(strs)));
|
||||
}
|
||||
|
||||
static int probe_kern_btf_func(void)
|
||||
{
|
||||
static const char strs[] = "\0int\0x\0a";
|
||||
/* void x(int a) {} */
|
||||
__u32 types[] = {
|
||||
/* int */
|
||||
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
|
||||
/* FUNC_PROTO */ /* [2] */
|
||||
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
|
||||
BTF_PARAM_ENC(7, 1),
|
||||
/* FUNC x */ /* [3] */
|
||||
BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
|
||||
};
|
||||
|
||||
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
|
||||
strs, sizeof(strs)));
|
||||
}
|
||||
|
||||
static int probe_kern_btf_func_global(void)
|
||||
{
|
||||
static const char strs[] = "\0int\0x\0a";
|
||||
/* static void x(int a) {} */
|
||||
__u32 types[] = {
|
||||
/* int */
|
||||
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
|
||||
/* FUNC_PROTO */ /* [2] */
|
||||
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
|
||||
BTF_PARAM_ENC(7, 1),
|
||||
/* FUNC x BTF_FUNC_GLOBAL */ /* [3] */
|
||||
BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2),
|
||||
};
|
||||
|
||||
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
|
||||
strs, sizeof(strs)));
|
||||
}
|
||||
|
||||
static int probe_kern_btf_datasec(void)
|
||||
{
|
||||
static const char strs[] = "\0x\0.data";
|
||||
/* static int a; */
|
||||
__u32 types[] = {
|
||||
/* int */
|
||||
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
|
||||
/* VAR x */ /* [2] */
|
||||
BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
|
||||
BTF_VAR_STATIC,
|
||||
/* DATASEC val */ /* [3] */
|
||||
BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
|
||||
BTF_VAR_SECINFO_ENC(2, 0, 4),
|
||||
};
|
||||
|
||||
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
|
||||
strs, sizeof(strs)));
|
||||
}
|
||||
|
||||
static int probe_kern_btf_float(void)
|
||||
{
|
||||
static const char strs[] = "\0float";
|
||||
__u32 types[] = {
|
||||
/* float */
|
||||
BTF_TYPE_FLOAT_ENC(1, 4),
|
||||
};
|
||||
|
||||
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
|
||||
strs, sizeof(strs)));
|
||||
}
|
||||
|
||||
static int probe_kern_btf_decl_tag(void)
|
||||
{
|
||||
static const char strs[] = "\0tag";
|
||||
__u32 types[] = {
|
||||
/* int */
|
||||
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
|
||||
/* VAR x */ /* [2] */
|
||||
BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
|
||||
BTF_VAR_STATIC,
|
||||
/* attr */
|
||||
BTF_TYPE_DECL_TAG_ENC(1, 2, -1),
|
||||
};
|
||||
|
||||
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
|
||||
strs, sizeof(strs)));
|
||||
}
|
||||
|
||||
static int probe_kern_btf_type_tag(void)
|
||||
{
|
||||
static const char strs[] = "\0tag";
|
||||
__u32 types[] = {
|
||||
/* int */
|
||||
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
|
||||
/* attr */
|
||||
BTF_TYPE_TYPE_TAG_ENC(1, 1), /* [2] */
|
||||
/* ptr */
|
||||
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2), /* [3] */
|
||||
};
|
||||
|
||||
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
|
||||
strs, sizeof(strs)));
|
||||
}
|
||||
|
||||
static int probe_kern_array_mmap(void)
|
||||
{
|
||||
LIBBPF_OPTS(bpf_map_create_opts, opts, .map_flags = BPF_F_MMAPABLE);
|
||||
int fd;
|
||||
|
||||
fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_mmap", sizeof(int), sizeof(int), 1, &opts);
|
||||
return probe_fd(fd);
|
||||
}
|
||||
|
||||
static int probe_kern_exp_attach_type(void)
|
||||
{
|
||||
LIBBPF_OPTS(bpf_prog_load_opts, opts, .expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE);
|
||||
struct bpf_insn insns[] = {
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
};
|
||||
int fd, insn_cnt = ARRAY_SIZE(insns);
|
||||
|
||||
/* use any valid combination of program type and (optional)
|
||||
* non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS)
|
||||
* to see if kernel supports expected_attach_type field for
|
||||
* BPF_PROG_LOAD command
|
||||
*/
|
||||
fd = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SOCK, NULL, "GPL", insns, insn_cnt, &opts);
|
||||
return probe_fd(fd);
|
||||
}
|
||||
|
||||
static int probe_kern_probe_read_kernel(void)
|
||||
{
|
||||
struct bpf_insn insns[] = {
|
||||
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), /* r1 = r10 (fp) */
|
||||
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), /* r1 += -8 */
|
||||
BPF_MOV64_IMM(BPF_REG_2, 8), /* r2 = 8 */
|
||||
BPF_MOV64_IMM(BPF_REG_3, 0), /* r3 = 0 */
|
||||
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel),
|
||||
BPF_EXIT_INSN(),
|
||||
};
|
||||
int fd, insn_cnt = ARRAY_SIZE(insns);
|
||||
|
||||
fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL);
|
||||
return probe_fd(fd);
|
||||
}
|
||||
|
||||
static int probe_prog_bind_map(void)
|
||||
{
|
||||
char *cp, errmsg[STRERR_BUFSIZE];
|
||||
struct bpf_insn insns[] = {
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
};
|
||||
int ret, map, prog, insn_cnt = ARRAY_SIZE(insns);
|
||||
|
||||
map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_det_bind", sizeof(int), 32, 1, NULL);
|
||||
if (map < 0) {
|
||||
ret = -errno;
|
||||
cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
|
||||
pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
|
||||
__func__, cp, -ret);
|
||||
return ret;
|
||||
}
|
||||
|
||||
prog = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL);
|
||||
if (prog < 0) {
|
||||
close(map);
|
||||
return 0;
|
||||
}
|
||||
|
||||
ret = bpf_prog_bind_map(prog, map, NULL);
|
||||
|
||||
close(map);
|
||||
close(prog);
|
||||
|
||||
return ret >= 0;
|
||||
}
|
||||
|
||||
static int probe_module_btf(void)
|
||||
{
|
||||
static const char strs[] = "\0int";
|
||||
__u32 types[] = {
|
||||
/* int */
|
||||
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
|
||||
};
|
||||
struct bpf_btf_info info;
|
||||
__u32 len = sizeof(info);
|
||||
char name[16];
|
||||
int fd, err;
|
||||
|
||||
fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs));
|
||||
if (fd < 0)
|
||||
return 0; /* BTF not supported at all */
|
||||
|
||||
memset(&info, 0, sizeof(info));
|
||||
info.name = ptr_to_u64(name);
|
||||
info.name_len = sizeof(name);
|
||||
|
||||
/* check that BPF_OBJ_GET_INFO_BY_FD supports specifying name pointer;
|
||||
* kernel's module BTF support coincides with support for
|
||||
* name/name_len fields in struct bpf_btf_info.
|
||||
*/
|
||||
err = bpf_btf_get_info_by_fd(fd, &info, &len);
|
||||
close(fd);
|
||||
return !err;
|
||||
}
|
||||
|
||||
static int probe_perf_link(void)
|
||||
{
|
||||
struct bpf_insn insns[] = {
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
};
|
||||
int prog_fd, link_fd, err;
|
||||
|
||||
prog_fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL",
|
||||
insns, ARRAY_SIZE(insns), NULL);
|
||||
if (prog_fd < 0)
|
||||
return -errno;
|
||||
|
||||
/* use invalid perf_event FD to get EBADF, if link is supported;
|
||||
* otherwise EINVAL should be returned
|
||||
*/
|
||||
link_fd = bpf_link_create(prog_fd, -1, BPF_PERF_EVENT, NULL);
|
||||
err = -errno; /* close() can clobber errno */
|
||||
|
||||
if (link_fd >= 0)
|
||||
close(link_fd);
|
||||
close(prog_fd);
|
||||
|
||||
return link_fd < 0 && err == -EBADF;
|
||||
}
|
||||
|
||||
static int probe_uprobe_multi_link(void)
|
||||
{
|
||||
LIBBPF_OPTS(bpf_prog_load_opts, load_opts,
|
||||
.expected_attach_type = BPF_TRACE_UPROBE_MULTI,
|
||||
);
|
||||
LIBBPF_OPTS(bpf_link_create_opts, link_opts);
|
||||
struct bpf_insn insns[] = {
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
};
|
||||
int prog_fd, link_fd, err;
|
||||
unsigned long offset = 0;
|
||||
|
||||
prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL",
|
||||
insns, ARRAY_SIZE(insns), &load_opts);
|
||||
if (prog_fd < 0)
|
||||
return -errno;
|
||||
|
||||
/* Creating uprobe in '/' binary should fail with -EBADF. */
|
||||
link_opts.uprobe_multi.path = "/";
|
||||
link_opts.uprobe_multi.offsets = &offset;
|
||||
link_opts.uprobe_multi.cnt = 1;
|
||||
|
||||
link_fd = bpf_link_create(prog_fd, -1, BPF_TRACE_UPROBE_MULTI, &link_opts);
|
||||
err = -errno; /* close() can clobber errno */
|
||||
|
||||
if (link_fd >= 0)
|
||||
close(link_fd);
|
||||
close(prog_fd);
|
||||
|
||||
return link_fd < 0 && err == -EBADF;
|
||||
}
|
||||
|
||||
static int probe_kern_bpf_cookie(void)
|
||||
{
|
||||
struct bpf_insn insns[] = {
|
||||
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_attach_cookie),
|
||||
BPF_EXIT_INSN(),
|
||||
};
|
||||
int ret, insn_cnt = ARRAY_SIZE(insns);
|
||||
|
||||
ret = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", insns, insn_cnt, NULL);
|
||||
return probe_fd(ret);
|
||||
}
|
||||
|
||||
static int probe_kern_btf_enum64(void)
|
||||
{
|
||||
static const char strs[] = "\0enum64";
|
||||
__u32 types[] = {
|
||||
BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_ENUM64, 0, 0), 8),
|
||||
};
|
||||
|
||||
return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
|
||||
strs, sizeof(strs)));
|
||||
}
|
||||
|
||||
static int probe_kern_syscall_wrapper(void);
|
||||
|
||||
enum kern_feature_result {
|
||||
FEAT_UNKNOWN = 0,
|
||||
FEAT_SUPPORTED = 1,
|
||||
FEAT_MISSING = 2,
|
||||
};
|
||||
|
||||
struct kern_feature_cache {
|
||||
enum kern_feature_result res[__FEAT_CNT];
|
||||
};
|
||||
|
||||
typedef int (*feature_probe_fn)(void);
|
||||
|
||||
static struct kern_feature_cache feature_cache;
|
||||
|
||||
static struct kern_feature_desc {
|
||||
const char *desc;
|
||||
feature_probe_fn probe;
|
||||
} feature_probes[__FEAT_CNT] = {
|
||||
[FEAT_PROG_NAME] = {
|
||||
"BPF program name", probe_kern_prog_name,
|
||||
},
|
||||
[FEAT_GLOBAL_DATA] = {
|
||||
"global variables", probe_kern_global_data,
|
||||
},
|
||||
[FEAT_BTF] = {
|
||||
"minimal BTF", probe_kern_btf,
|
||||
},
|
||||
[FEAT_BTF_FUNC] = {
|
||||
"BTF functions", probe_kern_btf_func,
|
||||
},
|
||||
[FEAT_BTF_GLOBAL_FUNC] = {
|
||||
"BTF global function", probe_kern_btf_func_global,
|
||||
},
|
||||
[FEAT_BTF_DATASEC] = {
|
||||
"BTF data section and variable", probe_kern_btf_datasec,
|
||||
},
|
||||
[FEAT_ARRAY_MMAP] = {
|
||||
"ARRAY map mmap()", probe_kern_array_mmap,
|
||||
},
|
||||
[FEAT_EXP_ATTACH_TYPE] = {
|
||||
"BPF_PROG_LOAD expected_attach_type attribute",
|
||||
probe_kern_exp_attach_type,
|
||||
},
|
||||
[FEAT_PROBE_READ_KERN] = {
|
||||
"bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel,
|
||||
},
|
||||
[FEAT_PROG_BIND_MAP] = {
|
||||
"BPF_PROG_BIND_MAP support", probe_prog_bind_map,
|
||||
},
|
||||
[FEAT_MODULE_BTF] = {
|
||||
"module BTF support", probe_module_btf,
|
||||
},
|
||||
[FEAT_BTF_FLOAT] = {
|
||||
"BTF_KIND_FLOAT support", probe_kern_btf_float,
|
||||
},
|
||||
[FEAT_PERF_LINK] = {
|
||||
"BPF perf link support", probe_perf_link,
|
||||
},
|
||||
[FEAT_BTF_DECL_TAG] = {
|
||||
"BTF_KIND_DECL_TAG support", probe_kern_btf_decl_tag,
|
||||
},
|
||||
[FEAT_BTF_TYPE_TAG] = {
|
||||
"BTF_KIND_TYPE_TAG support", probe_kern_btf_type_tag,
|
||||
},
|
||||
[FEAT_MEMCG_ACCOUNT] = {
|
||||
"memcg-based memory accounting", probe_memcg_account,
|
||||
},
|
||||
[FEAT_BPF_COOKIE] = {
|
||||
"BPF cookie support", probe_kern_bpf_cookie,
|
||||
},
|
||||
[FEAT_BTF_ENUM64] = {
|
||||
"BTF_KIND_ENUM64 support", probe_kern_btf_enum64,
|
||||
},
|
||||
[FEAT_SYSCALL_WRAPPER] = {
|
||||
"Kernel using syscall wrapper", probe_kern_syscall_wrapper,
|
||||
},
|
||||
[FEAT_UPROBE_MULTI_LINK] = {
|
||||
"BPF multi-uprobe link support", probe_uprobe_multi_link,
|
||||
},
|
||||
};
|
||||
|
||||
bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id)
|
||||
{
|
||||
struct kern_feature_desc *feat = &feature_probes[feat_id];
|
||||
int ret;
|
||||
|
||||
/* assume global feature cache, unless custom one is provided */
|
||||
if (!cache)
|
||||
cache = &feature_cache;
|
||||
|
||||
if (READ_ONCE(cache->res[feat_id]) == FEAT_UNKNOWN) {
|
||||
ret = feat->probe();
|
||||
if (ret > 0) {
|
||||
WRITE_ONCE(cache->res[feat_id], FEAT_SUPPORTED);
|
||||
} else if (ret == 0) {
|
||||
WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
|
||||
} else {
|
||||
pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret);
|
||||
WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
|
||||
}
|
||||
}
|
||||
|
||||
return READ_ONCE(cache->res[feat_id]) == FEAT_SUPPORTED;
|
||||
}
|
||||
|
||||
bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
|
||||
{
|
||||
if (obj && obj->gen_loader)
|
||||
|
|
@ -11067,7 +10606,7 @@ static const char *arch_specific_syscall_pfx(void)
|
|||
#endif
|
||||
}
|
||||
|
||||
static int probe_kern_syscall_wrapper(void)
|
||||
int probe_kern_syscall_wrapper(void)
|
||||
{
|
||||
char syscall_name[64];
|
||||
const char *ksys_pfx;
|
||||
|
|
|
|||
|
|
@ -361,10 +361,20 @@ enum kern_feature_id {
|
|||
__FEAT_CNT,
|
||||
};
|
||||
|
||||
struct kern_feature_cache;
|
||||
enum kern_feature_result {
|
||||
FEAT_UNKNOWN = 0,
|
||||
FEAT_SUPPORTED = 1,
|
||||
FEAT_MISSING = 2,
|
||||
};
|
||||
|
||||
struct kern_feature_cache {
|
||||
enum kern_feature_result res[__FEAT_CNT];
|
||||
};
|
||||
|
||||
bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id);
|
||||
bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
|
||||
|
||||
int probe_kern_syscall_wrapper(void);
|
||||
int probe_memcg_account(void);
|
||||
int bump_rlimit_memlock(void);
|
||||
|
||||
|
|
@ -626,4 +636,6 @@ int elf_resolve_syms_offsets(const char *binary_path, int cnt,
|
|||
int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
|
||||
unsigned long **poffsets, size_t *pcnt);
|
||||
|
||||
int probe_fd(int fd);
|
||||
|
||||
#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
|
||||
|
|
|
|||
|
|
@ -2,5 +2,8 @@
|
|||
#ifndef __LIBBPF_STR_ERROR_H
|
||||
#define __LIBBPF_STR_ERROR_H
|
||||
|
||||
#define STRERR_BUFSIZE 128
|
||||
|
||||
char *libbpf_strerror_r(int err, char *dst, int len);
|
||||
|
||||
#endif /* __LIBBPF_STR_ERROR_H */
|
||||
|
|
|
|||
Loading…
Reference in New Issue