forked from mirrors/linux
4ce16ddd71
Convert numeric error codes into the string representations in log messages in the rest of libbpf source files. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20241111212919.368971-5-mykyta.yatsenko5@gmail.com
610 lines
17 KiB
C
610 lines
17 KiB
C
// 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(int token_fd)
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{
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const size_t attr_sz = offsetofend(union bpf_attr, prog_token_fd);
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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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attr.prog_token_fd = token_fd;
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if (token_fd)
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attr.prog_flags |= BPF_F_TOKEN_FD;
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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(int token_fd)
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{
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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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LIBBPF_OPTS(bpf_map_create_opts, map_opts,
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.token_fd = token_fd,
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.map_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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);
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LIBBPF_OPTS(bpf_prog_load_opts, prog_opts,
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.token_fd = token_fd,
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.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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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, &map_opts);
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if (map < 0) {
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ret = -errno;
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pr_warn("Error in %s(): %s. Couldn't create simple array map.\n",
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__func__, errstr(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, &prog_opts);
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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(int token_fd)
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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), token_fd));
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}
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static int probe_kern_btf_func(int token_fd)
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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), token_fd));
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}
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static int probe_kern_btf_func_global(int token_fd)
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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), token_fd));
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}
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static int probe_kern_btf_datasec(int token_fd)
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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), token_fd));
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}
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static int probe_kern_btf_qmark_datasec(int token_fd)
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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 ?.data */ /* [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), token_fd));
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}
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static int probe_kern_btf_float(int token_fd)
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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), token_fd));
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}
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static int probe_kern_btf_decl_tag(int token_fd)
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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), token_fd));
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}
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static int probe_kern_btf_type_tag(int token_fd)
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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), token_fd));
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}
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static int probe_kern_array_mmap(int token_fd)
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{
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LIBBPF_OPTS(bpf_map_create_opts, opts,
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.map_flags = BPF_F_MMAPABLE | (token_fd ? BPF_F_TOKEN_FD : 0),
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.token_fd = token_fd,
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);
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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(int token_fd)
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{
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LIBBPF_OPTS(bpf_prog_load_opts, opts,
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.expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE,
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.token_fd = token_fd,
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.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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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 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(int token_fd)
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{
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LIBBPF_OPTS(bpf_prog_load_opts, opts,
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.token_fd = token_fd,
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.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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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, &opts);
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return probe_fd(fd);
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}
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static int probe_prog_bind_map(int token_fd)
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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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LIBBPF_OPTS(bpf_map_create_opts, map_opts,
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.token_fd = token_fd,
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.map_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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);
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LIBBPF_OPTS(bpf_prog_load_opts, prog_opts,
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.token_fd = token_fd,
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.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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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, &map_opts);
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if (map < 0) {
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ret = -errno;
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pr_warn("Error in %s(): %s. Couldn't create simple array map.\n",
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__func__, errstr(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, &prog_opts);
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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(int token_fd)
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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), token_fd);
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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(int token_fd)
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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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LIBBPF_OPTS(bpf_prog_load_opts, opts,
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.token_fd = token_fd,
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.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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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), &opts);
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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(int token_fd)
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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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.token_fd = token_fd,
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.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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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 || err != -EBADF) {
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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 0;
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}
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/* Initial multi-uprobe support in kernel didn't handle PID filtering
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* correctly (it was doing thread filtering, not process filtering).
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* So now we'll detect if PID filtering logic was fixed, and, if not,
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* we'll pretend multi-uprobes are not supported, if not.
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* Multi-uprobes are used in USDT attachment logic, and we need to be
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* conservative here, because multi-uprobe selection happens early at
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* load time, while the use of PID filtering is known late at
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* attachment time, at which point it's too late to undo multi-uprobe
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* selection.
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*
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* Creating uprobe with pid == -1 for (invalid) '/' binary will fail
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* early with -EINVAL on kernels with fixed PID filtering logic;
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* otherwise -ESRCH would be returned if passed correct binary path
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* (but we'll just get -BADF, of course).
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*/
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link_opts.uprobe_multi.pid = -1; /* invalid PID */
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link_opts.uprobe_multi.path = "/"; /* invalid 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 == -EINVAL;
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}
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static int probe_kern_bpf_cookie(int token_fd)
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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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LIBBPF_OPTS(bpf_prog_load_opts, opts,
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.token_fd = token_fd,
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.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
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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_TRACEPOINT, NULL, "GPL", insns, insn_cnt, &opts);
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return probe_fd(ret);
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}
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static int probe_kern_btf_enum64(int token_fd)
|
|
{
|
|
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), token_fd));
|
|
}
|
|
|
|
static int probe_kern_arg_ctx_tag(int token_fd)
|
|
{
|
|
static const char strs[] = "\0a\0b\0arg:ctx\0";
|
|
const __u32 types[] = {
|
|
/* [1] INT */
|
|
BTF_TYPE_INT_ENC(1 /* "a" */, BTF_INT_SIGNED, 0, 32, 4),
|
|
/* [2] PTR -> VOID */
|
|
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 0),
|
|
/* [3] FUNC_PROTO `int(void *a)` */
|
|
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 1),
|
|
BTF_PARAM_ENC(1 /* "a" */, 2),
|
|
/* [4] FUNC 'a' -> FUNC_PROTO (main prog) */
|
|
BTF_TYPE_ENC(1 /* "a" */, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 3),
|
|
/* [5] FUNC_PROTO `int(void *b __arg_ctx)` */
|
|
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 1),
|
|
BTF_PARAM_ENC(3 /* "b" */, 2),
|
|
/* [6] FUNC 'b' -> FUNC_PROTO (subprog) */
|
|
BTF_TYPE_ENC(3 /* "b" */, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 5),
|
|
/* [7] DECL_TAG 'arg:ctx' -> func 'b' arg 'b' */
|
|
BTF_TYPE_DECL_TAG_ENC(5 /* "arg:ctx" */, 6, 0),
|
|
};
|
|
const struct bpf_insn insns[] = {
|
|
/* main prog */
|
|
BPF_CALL_REL(+1),
|
|
BPF_EXIT_INSN(),
|
|
/* global subprog */
|
|
BPF_EMIT_CALL(BPF_FUNC_get_func_ip), /* needs PTR_TO_CTX */
|
|
BPF_EXIT_INSN(),
|
|
};
|
|
const struct bpf_func_info_min func_infos[] = {
|
|
{ 0, 4 }, /* main prog -> FUNC 'a' */
|
|
{ 2, 6 }, /* subprog -> FUNC 'b' */
|
|
};
|
|
LIBBPF_OPTS(bpf_prog_load_opts, opts,
|
|
.token_fd = token_fd,
|
|
.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
|
|
);
|
|
int prog_fd, btf_fd, insn_cnt = ARRAY_SIZE(insns);
|
|
|
|
btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs), token_fd);
|
|
if (btf_fd < 0)
|
|
return 0;
|
|
|
|
opts.prog_btf_fd = btf_fd;
|
|
opts.func_info = &func_infos;
|
|
opts.func_info_cnt = ARRAY_SIZE(func_infos);
|
|
opts.func_info_rec_size = sizeof(func_infos[0]);
|
|
|
|
prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, "det_arg_ctx",
|
|
"GPL", insns, insn_cnt, &opts);
|
|
close(btf_fd);
|
|
|
|
return probe_fd(prog_fd);
|
|
}
|
|
|
|
typedef int (*feature_probe_fn)(int /* token_fd */);
|
|
|
|
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,
|
|
},
|
|
[FEAT_ARG_CTX_TAG] = {
|
|
"kernel-side __arg_ctx tag", probe_kern_arg_ctx_tag,
|
|
},
|
|
[FEAT_BTF_QMARK_DATASEC] = {
|
|
"BTF DATASEC names starting from '?'", probe_kern_btf_qmark_datasec,
|
|
},
|
|
};
|
|
|
|
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(cache->token_fd);
|
|
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: %s\n",
|
|
feat->desc, errstr(ret));
|
|
WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
|
|
}
|
|
}
|
|
|
|
return READ_ONCE(cache->res[feat_id]) == FEAT_SUPPORTED;
|
|
}
|