/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

#define UNICODE
#include "system.h"
#include <string.h>
#ifdef _MSC_VER
#pragma warning(push,1) /* disable warnings within system headers */
#endif
#include <shellapi.h>
#ifdef _MSC_VER
#pragma warning(pop)
#endif

#include <cassert>
#include <memory>

#include <osl/security.h>
#include <osl/nlsupport.h>
#include <osl/mutex.h>
#include <osl/thread.h>
#include <sal/log.hxx>

#include <filetime.hxx>
#include <nlsupport.hxx>
#include "procimpl.hxx"
#include "sockimpl.hxx"
#include "file_url.hxx"
#include "path_helper.hxx"
#include <rtl/ustrbuf.h>
#include <rtl/alloc.h>

oslProcessError SAL_CALL osl_terminateProcess(oslProcess Process)
{
    if (Process == nullptr)
        return osl_Process_E_Unknown;

    HANDLE hProcess = static_cast<oslProcessImpl*>(Process)->m_hProcess;
    DWORD dwPID = GetProcessId(hProcess);

    // cannot be System Process (0x00000000)
    if (dwPID == 0x0)
        return osl_Process_E_InvalidError;

    // Test to see if we can create a thread in a process... adapted from:
    // * https://support.microsoft.com/en-us/help/178893/how-to-terminate-an-application-cleanly-in-win32
    // * http://www.drdobbs.com/a-safer-alternative-to-terminateprocess/184416547

    // TODO: we really should firstly check to see if we have access to create threads and only
    // duplicate the handle with elevated access if we don't have access... this can be done, but
    // it's not exactly easy - an example can be found here:
    // http://windowsitpro.com/site-files/windowsitpro.com/files/archive/windowsitpro.com/content/content/15989/listing_01.txt

    HANDLE hDupProcess = nullptr;


    // we need to make sure we can create a thread in the remote process, if the handle was created
    // in something that doesn't give us appropriate levels of access then we will need to give it the
    // desired level of access - if the process handle was grabbed from OpenProcess it's quite possible
    // that the handle doesn't have the appropriate level of access...

    // see https://msdn.microsoft.com/en-au/library/windows/desktop/ms684880(v=vs.85).aspx
    DWORD const dwAccessFlags = (PROCESS_CREATE_THREAD | PROCESS_QUERY_INFORMATION | PROCESS_VM_OPERATION
                                    | PROCESS_VM_WRITE | PROCESS_VM_READ);

    BOOL bHaveDuplHdl = DuplicateHandle(GetCurrentProcess(),    // handle to process that has handle
                                    hProcess,                   // handle to be duplicated
                                    GetCurrentProcess(),        // process that will get the dup handle
                                    &hDupProcess,               // store duplicate process handle here
                                    dwAccessFlags,              // desired access
                                    FALSE,                      // handle can't be inherited
                                    0);                         // zero means no additional action needed

    if (bHaveDuplHdl)
        hProcess = hDupProcess;     // so we were able to duplicate the handle, all good...
    else
        SAL_WARN("sal.osl", "Could not duplicate process handle, let's hope for the best...");

    DWORD dwProcessStatus = 0;
    HANDLE hRemoteThread = nullptr;

    if (GetExitCodeProcess(hProcess, &dwProcessStatus) && (dwProcessStatus == STILL_ACTIVE))
    {
        // We need to get the address of the Win32 procedure ExitProcess, can't call it
        // directly because we'll be calling the thunk and that will probably lead to an
        // access violation. Once we have the address, then we need to create a new
        // thread in the process (which we might need to run in the address space of
        // another process) and then call on ExitProcess to try to cleanly terminate that
        // process

        DWORD dwTID = 0;    // dummy variable as we don't need to track the thread ID

        // Note: we want to call on ExitProcess() and not TerminateProcess() - this is
        // because with ExitProcess() Windows notifies all attached dlls that the process
        // is detaching from the dll, but TerminateProcess() terminates all threads
        // immediately, doesn't call any termination handlers and doesn't notify any dlls
        // that it is detaching from them

        HINSTANCE hKernel = GetModuleHandleA("kernel32.dll");
        FARPROC pfnExitProc = GetProcAddress(hKernel, "ExitProcess");
        hRemoteThread = CreateRemoteThread(
                            hProcess,           /* process handle */
                            nullptr,               /* default security descriptor */
                            0,                  /* initial size of stack in bytes is default
                                                   size for executable */
                            reinterpret_cast<LPTHREAD_START_ROUTINE>(pfnExitProc), /* Win32 ExitProcess() */
                            reinterpret_cast<PVOID>(UINT(0)), /* ExitProcess(UINT uExitCode) argument */
                            0,                  /* value of 0 tells thread to run immediately
                                                   after creation */
                            &dwTID);            /* new remote thread's identifier */

    }

    bool bHasExited = false;

    if (hRemoteThread)
    {
        WaitForSingleObject(hProcess, INFINITE); // wait for process to terminate, never stop waiting...
        CloseHandle(hRemoteThread);              // close the thread handle to allow the process to exit
        bHasExited = true;
    }

    // need to close this duplicated process handle...
    if (bHaveDuplHdl)
        CloseHandle(hProcess);

    if (bHasExited)
        return osl_Process_E_None;

    // fallback - given that we we wait for an infinite time on WaitForSingleObject, this should
    // never occur... unless CreateRemoteThread failed
    SAL_WARN("sal.osl", "TerminateProcess(hProcess, 0) called - we should never get here!");
    return (TerminateProcess(hProcess, 0) == FALSE) ? osl_Process_E_Unknown : osl_Process_E_None;
}

oslProcess SAL_CALL osl_getProcess(oslProcessIdentifier Ident)
{
    oslProcessImpl* pProcImpl;
    HANDLE hProcess = OpenProcess(
        STANDARD_RIGHTS_REQUIRED | PROCESS_QUERY_INFORMATION | SYNCHRONIZE, FALSE, (DWORD)Ident);

    if (hProcess)
    {
        pProcImpl = static_cast< oslProcessImpl*>( rtl_allocateMemory(sizeof(oslProcessImpl)) );
        pProcImpl->m_hProcess  = hProcess;
        pProcImpl->m_IdProcess = Ident;
    }
    else
        pProcImpl = nullptr;

    return pProcImpl;
}

void SAL_CALL osl_freeProcessHandle(oslProcess Process)
{
    if (Process != nullptr)
    {
        CloseHandle(static_cast<oslProcessImpl*>(Process)->m_hProcess);

        rtl_freeMemory(Process);
    }
}

oslProcessError SAL_CALL osl_getProcessInfo(oslProcess Process, oslProcessData Fields,
                                   oslProcessInfo* pInfo)
{
    HANDLE hProcess;
    DWORD  IdProcess;

    if (Process == nullptr)
    {
        hProcess  = GetCurrentProcess();
        IdProcess = GetCurrentProcessId();
    }
    else
    {
        hProcess  = static_cast<oslProcessImpl*>(Process)->m_hProcess;
        IdProcess = static_cast<oslProcessImpl*>(Process)->m_IdProcess;
    }

    if (! pInfo || (pInfo->Size != sizeof(oslProcessInfo)))
        return osl_Process_E_Unknown;

    pInfo->Fields = 0;

    if (Fields & osl_Process_IDENTIFIER)
    {
        pInfo->Ident  = IdProcess;
        pInfo->Fields |= osl_Process_IDENTIFIER;
    }

    if (Fields & osl_Process_EXITCODE)
    {
        if (GetExitCodeProcess(hProcess, &(pInfo->Code)) && (pInfo->Code != STILL_ACTIVE))
            pInfo->Fields |= osl_Process_EXITCODE;
    }

    if (Fields & osl_Process_HEAPUSAGE)
    {
        void*   lpAddress=nullptr;
        MEMORY_BASIC_INFORMATION Info;

        pInfo->HeapUsage = 0;

        do
        {
            if (VirtualQueryEx(hProcess, lpAddress, &Info, sizeof(Info)) == 0)
                break;

            if ((Info.State == MEM_COMMIT) && (Info.Type == MEM_PRIVATE))
                pInfo->HeapUsage += Info.RegionSize;

            lpAddress = static_cast<LPBYTE>(lpAddress) + Info.RegionSize;
        }
        while (reinterpret_cast<uintptr_t>(lpAddress) <= (uintptr_t)0x7FFFFFFF); // 2GB address space

        pInfo->Fields |= osl_Process_HEAPUSAGE;
    }

    if (Fields & osl_Process_CPUTIMES)
    {
        FILETIME CreationTime, ExitTime, KernelTime, UserTime;

        if (GetProcessTimes(hProcess, &CreationTime, &ExitTime,
                                      &KernelTime, &UserTime))
        {
            __int64 Value;

            Value = osl::detail::getFiletime(UserTime);
            pInfo->UserTime.Seconds   = (unsigned long) (Value / 10000000L);
            pInfo->UserTime.Nanosec   = (unsigned long)((Value % 10000000L) * 100);

            Value = osl::detail::getFiletime(KernelTime);
            pInfo->SystemTime.Seconds = (unsigned long) (Value / 10000000L);
            pInfo->SystemTime.Nanosec = (unsigned long)((Value % 10000000L) * 100);

            pInfo->Fields |= osl_Process_CPUTIMES;
        }
    }

    return (pInfo->Fields == Fields) ? osl_Process_E_None : osl_Process_E_Unknown;
}

oslProcessError SAL_CALL osl_joinProcess(oslProcess Process)
{
    return osl_joinProcessWithTimeout(Process, nullptr);
}

oslProcessError SAL_CALL osl_joinProcessWithTimeout(oslProcess Process, const TimeValue* pTimeout)
{
    DWORD           timeout   = INFINITE;
    oslProcessError osl_error = osl_Process_E_None;
    DWORD           ret;

    if (nullptr == Process)
        return osl_Process_E_Unknown;

    if (pTimeout)
        timeout = pTimeout->Seconds * 1000 + pTimeout->Nanosec / 1000000L;

    ret = WaitForSingleObject(static_cast<oslProcessImpl*>(Process)->m_hProcess, timeout);

    if (WAIT_FAILED == ret)
        osl_error = osl_Process_E_Unknown;
    else if (WAIT_TIMEOUT == ret)
        osl_error = osl_Process_E_TimedOut;

    return osl_error;
}

namespace {

oslProcessError bootstrap_getExecutableFile(rtl_uString ** ppFileURL)
{
    oslProcessError result = osl_Process_E_NotFound;

    ::osl::LongPathBuffer< sal_Unicode > aBuffer( MAX_LONG_PATH );
    DWORD buflen = 0;

    if ((buflen = GetModuleFileNameW (nullptr, ::osl::mingw_reinterpret_cast<LPWSTR>(aBuffer), aBuffer.getBufSizeInSymbols())) > 0)
    {
        rtl_uString * pAbsPath = nullptr;
        rtl_uString_newFromStr_WithLength (&pAbsPath, aBuffer, buflen);
        if (pAbsPath)
        {
            /* Convert from path to url. */
            if (osl_getFileURLFromSystemPath (pAbsPath, ppFileURL) == osl_File_E_None)
            {
                /* Success. */
                result = osl_Process_E_None;
            }
            rtl_uString_release (pAbsPath);
        }
    }

    return result;
}

}

struct CommandArgs_Impl
{
    sal_uInt32     m_nCount;
    rtl_uString ** m_ppArgs;
};

static struct CommandArgs_Impl g_command_args =
{
    0,
    nullptr
};

#ifdef _MSC_VER
#pragma warning( push )
#pragma warning( disable: 4100 )
#endif
static rtl_uString ** osl_createCommandArgs_Impl (int argc, char **)
{
    rtl_uString ** ppArgs =
        static_cast<rtl_uString**>(rtl_allocateZeroMemory (argc * sizeof(rtl_uString*)));
    if (ppArgs != nullptr)
    {
        int i;
        int nArgs;
        LPWSTR *wargv = CommandLineToArgvW( GetCommandLineW(), &nArgs );
        assert( nArgs == argc );
        for (i = 0; i < nArgs; i++)
        {
            /* Convert to unicode */
            rtl_uString_newFromStr( &(ppArgs[i]), reinterpret_cast<const sal_Unicode*>(wargv[i]) );
        }
        if (ppArgs[0] != nullptr)
        {
            /* Ensure absolute path */
            ::osl::LongPathBuffer< sal_Unicode > aBuffer( MAX_LONG_PATH );
            DWORD dwResult = 0;

            dwResult = SearchPath (
                nullptr, reinterpret_cast<LPCWSTR>(ppArgs[0]->buffer), L".exe", aBuffer.getBufSizeInSymbols(), ::osl::mingw_reinterpret_cast<LPWSTR>(aBuffer), nullptr);
            if ((0 < dwResult) && (dwResult < aBuffer.getBufSizeInSymbols()))
            {
                /* Replace argv[0] with its absolute path */
                rtl_uString_newFromStr_WithLength(
                    &(ppArgs[0]), aBuffer, dwResult);
            }
        }
        if (ppArgs[0] != nullptr)
        {
            /* Convert to FileURL, see @ osl_getExecutableFile() */
            rtl_uString * pResult = nullptr;
            osl_getFileURLFromSystemPath (ppArgs[0], &pResult);
            if (pResult != nullptr)
            {
                rtl_uString_assign (&(ppArgs[0]), pResult);
                rtl_uString_release (pResult);
            }
        }
    }
    return ppArgs;

}
#ifdef _MSC_VER
#pragma warning( pop )
#endif

oslProcessError SAL_CALL osl_getExecutableFile( rtl_uString **ppustrFile )
{
    osl_acquireMutex (*osl_getGlobalMutex());
    if (g_command_args.m_nCount == 0)
    {
        osl_releaseMutex (*osl_getGlobalMutex());
        return bootstrap_getExecutableFile(ppustrFile);
    }

    /* CommandArgs set. Obtain arv[0]. */
    rtl_uString_assign (ppustrFile, g_command_args.m_ppArgs[0]);
    osl_releaseMutex (*osl_getGlobalMutex());
    return osl_Process_E_None;
}

sal_uInt32 SAL_CALL osl_getCommandArgCount()
{
    sal_uInt32 result = 0;

    osl_acquireMutex (*osl_getGlobalMutex());
    SAL_INFO_IF(
        g_command_args.m_nCount == 0, "sal.osl",
        "osl_getCommandArgCount w/o prior call to osl_setCommandArgs");
    if (g_command_args.m_nCount > 0)
    {
        /* We're not counting argv[0] here. */
        result = g_command_args.m_nCount - 1;
    }
    osl_releaseMutex (*osl_getGlobalMutex());

    return result;
}

oslProcessError SAL_CALL osl_getCommandArg( sal_uInt32 nArg, rtl_uString **strCommandArg)
{
    oslProcessError result = osl_Process_E_NotFound;

    osl_acquireMutex (*osl_getGlobalMutex());
    assert(g_command_args.m_nCount > 0);
    if (g_command_args.m_nCount > (nArg + 1))
    {
        /* We're not counting argv[0] here. */
        rtl_uString_assign (strCommandArg, g_command_args.m_ppArgs[nArg + 1]);
        result = osl_Process_E_None;
    }
    osl_releaseMutex (*osl_getGlobalMutex());

    return result;
}

void SAL_CALL osl_setCommandArgs (int argc, char ** argv)
{
    assert(argc > 0);
    osl_acquireMutex (*osl_getGlobalMutex());
    SAL_WARN_IF(g_command_args.m_nCount != 0, "sal.osl", "args already set");
    if (g_command_args.m_nCount == 0)
    {
        rtl_uString** ppArgs = osl_createCommandArgs_Impl (argc, argv);
        if (ppArgs != nullptr)
        {
            g_command_args.m_nCount = argc;
            g_command_args.m_ppArgs = ppArgs;
        }
    }
    osl_releaseMutex (*osl_getGlobalMutex());
}

#define ENV_BUFFER_SIZE (32*1024-1)

oslProcessError SAL_CALL osl_getEnvironment(rtl_uString *ustrVar, rtl_uString **ustrValue)
{
    WCHAR buff[ENV_BUFFER_SIZE];

    if (GetEnvironmentVariableW(reinterpret_cast<LPCWSTR>(ustrVar->buffer), buff, ENV_BUFFER_SIZE) > 0)
    {
        rtl_uString_newFromStr(ustrValue, reinterpret_cast<const sal_Unicode*>(buff));
        return osl_Process_E_None;
    }
    return osl_Process_E_Unknown;
}

oslProcessError SAL_CALL osl_setEnvironment(rtl_uString *ustrVar, rtl_uString *ustrValue)
{
    // set Windows environment variable
    LPCWSTR lpName = reinterpret_cast<LPCWSTR>(ustrVar->buffer);
    LPCWSTR lpValue = reinterpret_cast<LPCWSTR>(ustrValue->buffer);
    if (SetEnvironmentVariableW(lpName, lpValue))
    {
        auto buffer = std::unique_ptr<wchar_t[]>(
            new wchar_t[wcslen(lpName) + 1 + wcslen(lpValue) + 1]);
        wcscpy(buffer.get(), lpName);
        wcscat(buffer.get(), L"=");
        wcscat(buffer.get(), lpValue);
        _wputenv(buffer.get());
        return osl_Process_E_None;
    }
    return osl_Process_E_Unknown;
}

oslProcessError SAL_CALL osl_clearEnvironment(rtl_uString *ustrVar)
{
    // delete the variable from the current process environment
    // by setting SetEnvironmentVariable's second parameter to NULL
    LPCWSTR lpName = reinterpret_cast<LPCWSTR>(ustrVar->buffer);
    if (SetEnvironmentVariableW(lpName, nullptr))
    {
        auto buffer = std::unique_ptr<wchar_t[]>(
            new wchar_t[wcslen(lpName) + 1 + 1]);
        wcscpy(buffer.get(), lpName);
        wcscat(buffer.get(), L"=");
        _wputenv(buffer.get());
        return osl_Process_E_None;
    }
    return osl_Process_E_Unknown;
}

oslProcessError SAL_CALL osl_getProcessWorkingDir( rtl_uString **pustrWorkingDir )
{
    ::osl::LongPathBuffer< sal_Unicode > aBuffer( MAX_LONG_PATH );
    DWORD   dwLen = 0;

    osl_acquireMutex( g_CurrentDirectoryMutex );
    dwLen = GetCurrentDirectory( aBuffer.getBufSizeInSymbols(), ::osl::mingw_reinterpret_cast<LPWSTR>(aBuffer) );
    osl_releaseMutex( g_CurrentDirectoryMutex );

    if ( dwLen && dwLen < aBuffer.getBufSizeInSymbols() )
    {
        oslFileError    eError;
        rtl_uString     *ustrTemp = nullptr;

        rtl_uString_newFromStr_WithLength( &ustrTemp, aBuffer, dwLen );
        eError = osl_getFileURLFromSystemPath( ustrTemp, pustrWorkingDir );

        rtl_uString_release( ustrTemp );

        if ( osl_File_E_None != eError )
            return osl_Process_E_Unknown;
        else
            return osl_Process_E_None;
    }
    else
        return osl_Process_E_Unknown;
}

static rtl_Locale * g_theProcessLocale = nullptr;

oslProcessError SAL_CALL osl_getProcessLocale( rtl_Locale ** ppLocale )
{
    osl_acquireMutex( *osl_getGlobalMutex() );

    /* determine the users default locale */
    if( nullptr == g_theProcessLocale )
        imp_getProcessLocale( &g_theProcessLocale );

    /* or return the cached value */
    *ppLocale = g_theProcessLocale;

    osl_releaseMutex( *osl_getGlobalMutex() );
    return osl_Process_E_None;
}

oslProcessError SAL_CALL osl_setProcessLocale( rtl_Locale * pLocale )
{
    osl_acquireMutex( *osl_getGlobalMutex() );

    /* check if locale is supported */
    if( RTL_TEXTENCODING_DONTKNOW == osl_getTextEncodingFromLocale( pLocale ) )
        return osl_Process_E_Unknown;

    /* just remember the locale here */
    g_theProcessLocale = pLocale;

    osl_releaseMutex( *osl_getGlobalMutex() );
    return osl_Process_E_None;
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */