sys_info.hpp

/*
    SPDX-License-Identifier: MIT
    Copyright © 2023-2024 Amebis
*/
 
#pragma once
 
#include "assert.hpp"
#include "compat.hpp"
#include "string.hpp"
#include "system.hpp"
#if defined(_WIN32)
#include "windows.h"
#include <security.h>
#include <stdlib.h>
#include <tchar.h>
#else
#include <sys/utsname.h>
#endif
#include <map>
#include <memory>
 
#if defined(__GNUC__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wexit-time-destructors"
#endif
 
namespace stdex
{
    enum class platform_id : uint16_t {
#ifdef _WIN32
        unknown = IMAGE_FILE_MACHINE_UNKNOWN,
        i386 = IMAGE_FILE_MACHINE_I386,
        x86_64 = IMAGE_FILE_MACHINE_AMD64,
        arm = IMAGE_FILE_MACHINE_ARMNT,
        aarch64 = IMAGE_FILE_MACHINE_ARM64,
#else
        unknown = 0,
        i386 = 0x014c,
        x86_64 = 0x8664,
        arm = 0x01c4,
        aarch64 = 0xaa64,
#endif
    };
 
    inline platform_id platform_from_name(_In_z_ const char* name)
    {
        struct platform_less {
            bool operator()(_In_z_ const char* a, _In_z_ const char* b) const
            {
                return stricmp(a, b) < 0;
            }
        };
        static const std::map<const char*, platform_id, platform_less> platforms = {
            { "aarch64", platform_id::aarch64 },
            { "arm", platform_id::arm },
            { "i386", platform_id::i386 },
            { "x86_64", platform_id::x86_64 },
        };
        if (auto el = platforms.find(name); el != platforms.end())
            return el->second;
        return platform_id::unknown;
    }
 
    inline const struct sys_info_t
    {
#if _M_IX86 || __i386__
        static constexpr platform_id process_platform = platform_id::i386;
#elif _M_X64 /* _M_ARM64EC is introducing as x64 */ || __x86_64__
        static constexpr platform_id process_platform = platform_id::x86_64;
#elif _M_ARM || __arm__
        static constexpr platform_id process_platform = platform_id::arm;
#elif _M_ARM64 || __aarch64__
        static constexpr platform_id process_platform = platform_id::aarch64;
#else
        #error Unknown platform
#endif
 
        platform_id os_platform;
 
#ifdef _WIN32
        bool wow64;
#endif
 
        bool interactive_process;
 
        bool admin;
 
        bool elevated;
 
        sstring username;
 
        sys_info_t() :
            os_platform(platform_id::unknown),
#ifdef _WIN32
            wow64(false),
#endif
            interactive_process(true),
            admin(false),
            elevated(false)
        {
#ifdef _WIN32
            HMODULE kernel32_handle;
            kernel32_handle = LoadLibrary(_T("kernel32.dll"));
            stdex_assert(kernel32_handle);
            BOOL(WINAPI * IsWow64Process2)(HANDLE hProcess, USHORT * pProcessMachine, USHORT * pNativeMachine);
            *reinterpret_cast<FARPROC*>(&IsWow64Process2) = GetProcAddress(kernel32_handle, "IsWow64Process2");
            HANDLE process = GetCurrentProcess();
            USHORT process_machine;
#ifndef _WIN64
            BOOL Wow64Process;
#endif
            if (IsWow64Process2 && IsWow64Process2(process, &process_machine, reinterpret_cast<USHORT*>(&os_platform))) {
                wow64 = process_machine != IMAGE_FILE_MACHINE_UNKNOWN;
            }
#ifdef _WIN64
            else {
                os_platform = process_platform;
                wow64 = false;
            }
#else
            else if (IsWow64Process(process, &Wow64Process)) {
                if (Wow64Process) {
                    os_platform = platform_id::x86_64;
                    wow64 = true;
                }
                else {
                    os_platform = process_platform;
                    wow64 = false;
                }
            }
#endif
            FreeLibrary(kernel32_handle);
#else
            memset(&m_utsn, 0, sizeof(m_utsn));
            if (uname(&m_utsn) != -1)
                os_platform = platform_from_name(m_utsn.machine);
#endif
 
#ifdef _WIN32
            HWINSTA hWinSta = GetProcessWindowStation();
            if (hWinSta) {
                TCHAR sName[MAX_PATH];
                if (GetUserObjectInformation(hWinSta, UOI_NAME, sName, sizeof(sName), NULL)) {
                    sName[_countof(sName) - 1] = 0;
                    // Only "WinSta0" is interactive (Source: KB171890)
                    interactive_process = _tcsicmp(sName, _T("WinSta0")) == 0;
                }
            }
#else
            // TODO: Research interactive process vs service/agent/daemon on this platform.
#endif
 
#if defined(_WIN32)
            {
                HANDLE token_h;
                if (OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &token_h)) {
                    sys_object token(token_h);
 
                    TOKEN_ELEVATION elevation;
                    DWORD size = sizeof(TOKEN_ELEVATION);
                    if (GetTokenInformation(token_h, TokenElevation, &elevation, sizeof(elevation), &size))
                        elevated = elevation.TokenIsElevated;
 
                    GetTokenInformation(token.get(), TokenGroups, NULL, 0, &size);
                    std::unique_ptr<TOKEN_GROUPS> groups((TOKEN_GROUPS*)new uint8_t[size]);
                    if (GetTokenInformation(token.get(), TokenGroups, (LPVOID)groups.get(), size, &size)) {
                        SID_IDENTIFIER_AUTHORITY authority = SECURITY_NT_AUTHORITY;
                        PSID sid_admins_h = NULL;
                        if (AllocateAndInitializeSid(&authority, 2, SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS, 0, 0, 0, 0, 0, 0, &sid_admins_h)) {
                            struct SID_delete { void operator()(_In_ PSID p) const { FreeSid(p); } };
                            std::unique_ptr<void, SID_delete> sid_admins(sid_admins_h);
                            for (DWORD i = 0; i < groups->GroupCount; ++i)
                                if (EqualSid(sid_admins.get(), groups->Groups[i].Sid)) {
                                    admin = true;
                                    break;
                                }
                        }
                    }
                }
            }
#elif defined(__APPLE__)
            {
                gid_t gids[NGROUPS_MAX];
                for (int i = 0, n = getgroups(NGROUPS_MAX, gids); i < n; ++i) {
                    struct group* group = getgrgid(gids[i]);
                    if (!group) continue;
                    if (strcmp(group->gr_name, "admin") == 0) {
                        admin = true;
                        break;
                    }
                }
            }
 
            elevated = geteuid() == 0;
#else
            // TODO: Set admin.
            elevated = geteuid() == 0;
#endif
 
#ifdef _WIN32
#if defined(SECURITY_WIN32) || defined(SECURITY_KERNEL)
            {
                TCHAR szStackBuffer[0x100];
                ULONG ulSize = _countof(szStackBuffer);
                if (GetUserNameEx(NameSamCompatible, szStackBuffer, &ulSize))
                    username.assign(szStackBuffer, ulSize);
                if (GetLastError() == ERROR_MORE_DATA) {
                    // Allocate buffer on heap and retry.
                    username.resize(ulSize - 1);
                    if (!GetUserNameEx(NameSamCompatible, &username[0], &ulSize))
                        username.clear();
                }
            }
#endif
#else
            {
                struct passwd *pw = getpwuid(geteuid());
                if (pw && pw->pw_name)
                    username = pw->pw_name;
            }
#endif
        }
 
        static bool is_screen_reader()
        {
#ifdef _WIN32
            BOOL b;
            return SystemParametersInfo(SPI_GETSCREENREADER, 0, &b, 0) && b;
#else
            return false;
#endif
        }
 
    protected:
#ifndef _WIN32
        struct utsname m_utsn;
#endif
    } sys_info;
}
 
#if defined(__GNUC__)
#pragma GCC diagnostic pop
#endif