zircon/system/ulib/smbios/smbios-test.cpp

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <lib/smbios/smbios.h>
#include <fbl/array.h>
#include <memory>
#include <zxtest/zxtest.h>

namespace {

uint8_t ComputeChecksum(const uint8_t* data, size_t len) {
    unsigned int sum = 0;
    for (size_t i = 0; i < len; ++i) {
        sum += data[i];
    }
    return static_cast<uint8_t>(sum);
}
smbios::EntryPoint2_1 CreateFakeEntryPoint(const fbl::Array<uint8_t>& structs,
                                           uint16_t structures_count) {
    smbios::EntryPoint2_1 ep;
    memcpy(ep.anchor_string, "_SM_", 4);
    ep.checksum = 0;
    ep.length = sizeof(ep);
    ep.major_ver = 2;
    ep.minor_ver = 1;
    ep.max_struct_size = 256;
    ep.ep_rev = 0;
    memset(ep.formatted_area, 0, sizeof(ep.formatted_area));
    memcpy(ep.intermediate_anchor_string, "_DMI_", 5);
    ep.intermediate_checksum = 0;
    ep.struct_table_length = static_cast<uint16_t>(structs.size());
    ep.struct_table_phys = 0x1000; // Fake physical address
    ep.struct_count = structures_count;
    ep.bcd_rev = 0x21;

    // The specification defines the offsets for this checksum
    ep.intermediate_checksum = static_cast<uint8_t>(
            256u - ComputeChecksum(reinterpret_cast<const uint8_t*>(&ep) + 0x10, 0xf));
    ep.checksum = static_cast<uint8_t>(
            256 - ComputeChecksum(reinterpret_cast<const uint8_t*>(&ep), sizeof(ep)));

    return ep;
}

#define BIOS_STRING1 "string1"
#define BIOS_STRING2 "string2"

// Create fake SMBIOSv2.1 structures
void CreateFakeSmbios(smbios::EntryPoint2_1* ep, fbl::Array<uint8_t>* structs) {
    constexpr uint16_t kNumStructures = 2;
    // A double null terminates the string table
    const char bios_info_strings[] =
            BIOS_STRING1 "\0"
            BIOS_STRING2 "\0";
    const size_t bios_info_size = sizeof(smbios::BiosInformationStruct2_0) +
            sizeof(bios_info_strings);
    const char sys_info_strings[] = "\0";
    const size_t sys_info_size = sizeof(smbios::SystemInformationStruct2_1) +
            sizeof(sys_info_strings);
    const size_t struct_data_size = bios_info_size + sys_info_size;

    fbl::Array<uint8_t> struct_data(new uint8_t[struct_data_size](), struct_data_size);
    uint8_t* next_struct_data = struct_data.get();

    smbios::BiosInformationStruct2_0 bios_info = {};
    bios_info.hdr.type = smbios::StructType::BiosInfo;
    bios_info.hdr.length = sizeof(bios_info);
    bios_info.hdr.handle = 0;
    memcpy(next_struct_data, &bios_info, sizeof(bios_info));
    next_struct_data += sizeof(bios_info);
    memcpy(next_struct_data, bios_info_strings, sizeof(bios_info_strings));
    next_struct_data += sizeof(bios_info_strings);

    smbios::SystemInformationStruct2_1 sys_info = {};
    sys_info.hdr.type = smbios::StructType::SystemInfo;
    sys_info.hdr.length = sizeof(sys_info);
    sys_info.hdr.handle = 1;
    memcpy(next_struct_data, &sys_info, sizeof(sys_info));
    next_struct_data += sizeof(sys_info);
    memcpy(next_struct_data, sys_info_strings, sizeof(sys_info_strings));
    next_struct_data += sizeof(sys_info_strings);

    ASSERT_EQ(struct_data.get() + struct_data_size, next_struct_data);

    *ep = CreateFakeEntryPoint(struct_data, kNumStructures);
    ASSERT_TRUE(ep->IsValid());
    *structs = std::move(struct_data);
}

TEST(SmbiosTestCase, WalkStructs) {
    smbios::EntryPoint2_1 ep;
    fbl::Array<uint8_t> structs;
    ASSERT_NO_FATAL_FAILURES(CreateFakeSmbios(&ep, &structs));

    bool tables_seen[2] = {};
    auto walk_cb = [&ep, &tables_seen](smbios::SpecVersion version, const smbios::Header* h,
                                      const smbios::StringTable& st) {
        EXPECT_EQ(version.major_ver, ep.major_ver);
        EXPECT_EQ(version.minor_ver, ep.minor_ver);
        switch (h->type) {
        case smbios::StructType::BiosInfo:
        case smbios::StructType::SystemInfo: {
            EXPECT_FALSE(tables_seen[static_cast<size_t>(h->type)]);
            tables_seen[static_cast<size_t>(h->type)] = true;
            break;
        }
        default:
            ADD_FAILURE("Saw unexpected header type");
        }
        return ZX_OK;
    };
    ASSERT_OK(ep.WalkStructs(reinterpret_cast<uintptr_t>(structs.get()), walk_cb));
    ASSERT_TRUE(tables_seen[0]);
    ASSERT_TRUE(tables_seen[1]);
}

TEST(SmbiosTestCase, WalkStructsEarlyStop) {
    smbios::EntryPoint2_1 ep;
    fbl::Array<uint8_t> structs;
    ASSERT_NO_FATAL_FAILURES(CreateFakeSmbios(&ep, &structs));

    auto walk_cb = [](smbios::SpecVersion version, const smbios::Header* h,
                      const smbios::StringTable& st) {
        switch (h->type) {
        case smbios::StructType::BiosInfo: return ZX_ERR_STOP;
        case smbios::StructType::SystemInfo: {
            ADD_FAILURE("Iterator saw SystemInfo");
            break;
        }
        default:
            ADD_FAILURE("Saw unexpected header type");
        }
        return ZX_OK;
    };
    ASSERT_OK(ep.WalkStructs(reinterpret_cast<uintptr_t>(structs.get()), walk_cb));
}

TEST(SmbiosTestCase, GetString) {
    smbios::EntryPoint2_1 ep;
    fbl::Array<uint8_t> structs;
    ASSERT_NO_FATAL_FAILURES(CreateFakeSmbios(&ep, &structs));

    auto walk_cb = [](smbios::SpecVersion version, const smbios::Header* h,
                      const smbios::StringTable& st) {
        switch (h->type) {
        case smbios::StructType::BiosInfo: {
            const char* str = nullptr;
            EXPECT_OK(st.GetString(0, &str));
            EXPECT_STR_EQ("<null>", str);
            EXPECT_OK(st.GetString(1, &str));
            EXPECT_STR_EQ(BIOS_STRING1, str);
            EXPECT_OK(st.GetString(2, &str));
            EXPECT_STR_EQ(BIOS_STRING2, str);
            EXPECT_EQ(ZX_ERR_NOT_FOUND, st.GetString(3, &str));
            break;
        }
        case smbios::StructType::SystemInfo: {
            const char* str = nullptr;
            EXPECT_OK(st.GetString(0, &str));
            EXPECT_STR_EQ("<null>", str);
            EXPECT_EQ(ZX_ERR_NOT_FOUND, st.GetString(1, &str));
            break;
        }
        default:
            ADD_FAILURE("Saw unexpected header type");
        }
        return ZX_OK;
    };
    ASSERT_OK(ep.WalkStructs(reinterpret_cast<uintptr_t>(structs.get()), walk_cb));
}

} // namespace