PHP executed program fails

Question

I want to execute a C++ Program with my PHP Back-end. The C++ Program is responsible for removing usb devices like usb sticks from my PC. When I open the program (which is on a separate local drive) with the CLI without administrative rights, the program starts and finishes the job correctly.

When I start the program with PHP using exec("/path/to/my/program.exe and-parameters") which is literally the same way as from the CLI, the program just starts and returns "failed" so something is different when using the CLI.

The C++ Code:

//
// RemoveDriveByLetter.cpp by Uwe Sieber - www.uwe-sieber.de
//
// Simple demonstration how to prepare a disk drive for save removal
//
// Works with removable and fixed drives under W2K, XP, W2K3, Vista
//
// Console application - expects the drive letter of the drive to remove as parameter
//
// you are free to use this code in your projects
//


#include "stdafx.h"
#include <stdio.h>

#include <windows.h>

#include <Setupapi.h>
#include <winioctl.h>
#include <winioctl.h>
#include <cfgmgr32.h>
#include <string>


//-------------------------------------------------
DEVINST GetDrivesDevInstByDeviceNumber(long DeviceNumber, UINT DriveType, char* szDosDeviceName);
//-------------------------------------------------



//-------------------------------------------------
int main(int argc, char* argv[])
{

    /*if ( argc != 2 ) {
        return 1;       
    }*/
    char DriveLetter = argv[1][0];
    DriveLetter &= ~0x20; // uppercase



    if ( DriveLetter < 'A' || DriveLetter > 'Z' ) {
        return 1;
    }

    std::string path = "";
    path += DriveLetter;
    path.append(":\\");
    printf(path.c_str());

    char szRootPath[sizeof(path)] ="";
    strncpy(szRootPath, path.c_str(), sizeof(path));

    std::string device = "";
    device += DriveLetter;
    device.append(":");
    printf(device.c_str());

    char szDevicePath[sizeof(device)] = "";
    strncpy(szDevicePath, device.c_str(), sizeof(device));

    std::string accesspath = "";
    accesspath += "\\\\.\\";
    accesspath += device;
    printf(accesspath.c_str());

    char szVolumeAccessPath[sizeof(accesspath)] = "";   // "\\.\X:"  -> to open the volume
    strncpy(szVolumeAccessPath, accesspath.c_str(), sizeof(accesspath));

    long DeviceNumber = -1;

    // open the storage volume
    HANDLE hVolume = CreateFile(szVolumeAccessPath, 0, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, NULL, NULL);
    if (hVolume == INVALID_HANDLE_VALUE) {
        return 1;
    }

    // get the volume's device number
    STORAGE_DEVICE_NUMBER sdn;
    DWORD dwBytesReturned = 0;
    long res = DeviceIoControl(hVolume, IOCTL_STORAGE_GET_DEVICE_NUMBER, NULL, 0, &sdn, sizeof(sdn), &dwBytesReturned, NULL);
    if ( res ) {
        DeviceNumber = sdn.DeviceNumber;
    }
    CloseHandle(hVolume);

    if ( DeviceNumber == -1 ) {
        return 1;
    }

    // get the drive type which is required to match the device numbers correctely
    UINT DriveType = GetDriveType(szRootPath);

    // get the dos device name (like \device\floppy0) to decide if it's a floppy or not - who knows a better way?
    char szDosDeviceName[MAX_PATH];
    res = QueryDosDevice(szDevicePath, szDosDeviceName, MAX_PATH);
    if ( !res ) {
        return 1;
    }

    // get the device instance handle of the storage volume by means of a SetupDi enum and matching the device number
    DEVINST DevInst = GetDrivesDevInstByDeviceNumber(DeviceNumber, DriveType, szDosDeviceName);

    if ( DevInst == 0 ) {
        return 1;
    }

    PNP_VETO_TYPE VetoType = PNP_VetoTypeUnknown; 
    WCHAR VetoNameW[MAX_PATH];
    VetoNameW[0] = 0;
    bool bSuccess = false;

    // get drives's parent, e.g. the USB bridge, the SATA port, an IDE channel with two drives!
    DEVINST DevInstParent = 0;
    res = CM_Get_Parent(&DevInstParent, DevInst, 0); 

    for ( long tries=1; tries<=3; tries++ ) { // sometimes we need some tries...

        VetoNameW[0] = 0;

        // CM_Query_And_Remove_SubTree doesn't work for restricted users
        //res = CM_Query_And_Remove_SubTreeW(DevInstParent, &VetoType, VetoNameW, MAX_PATH, CM_REMOVE_NO_RESTART); // CM_Query_And_Remove_SubTreeA is not implemented under W2K!
        //res = CM_Query_And_Remove_SubTreeW(DevInstParent, NULL, NULL, 0, CM_REMOVE_NO_RESTART);  // with messagebox (W2K, Vista) or balloon (XP)

        res = CM_Request_Device_EjectW(DevInstParent, &VetoType, VetoNameW, MAX_PATH, 0);
        //res = CM_Request_Device_EjectW(DevInstParent, NULL, NULL, 0, 0); // with messagebox (W2K, Vista) or balloon (XP)

        bSuccess = (res==CR_SUCCESS && VetoType==PNP_VetoTypeUnknown);
        if ( bSuccess )  { 
            break;
        }

        Sleep(500); // required to give the next tries a chance!
    }

    if ( bSuccess ) {
        printf("Success\n\n");
        return 0;
    }

    printf("failed\n");

    printf("Result=0x%2X\n", res);

    if ( VetoNameW[0] ) {
        printf("VetoName=%ws)\n\n", VetoNameW);
    }   
    return 1;
}
//-----------------------------------------------------------

char* appendCharToCharArray(char* array, char a)
{
    size_t len = strlen(array);

    char* ret = new char[len+2];

    strcpy(ret, array);    
    ret[len] = a;
    ret[len+1] = '\0';

    return ret;
}


//----------------------------------------------------------------------
// returns the device instance handle of a storage volume or 0 on error
//----------------------------------------------------------------------
DEVINST GetDrivesDevInstByDeviceNumber(long DeviceNumber, UINT DriveType, char* szDosDeviceName)
{
    bool IsFloppy = (strstr(szDosDeviceName, "\\Floppy") != NULL); // who knows a better way?

    GUID* guid;

    switch (DriveType) {
    case DRIVE_REMOVABLE:
        if ( IsFloppy ) {
            guid = (GUID*)&GUID_DEVINTERFACE_FLOPPY;
        } else {
            guid = (GUID*)&GUID_DEVINTERFACE_DISK;
        }
        break;
    case DRIVE_FIXED:
        guid = (GUID*)&GUID_DEVINTERFACE_DISK;
        break;
    case DRIVE_CDROM:
        guid = (GUID*)&GUID_DEVINTERFACE_CDROM;
        break;
    default:
        return 0;
    }

    // Get device interface info set handle for all devices attached to system
    HDEVINFO hDevInfo = SetupDiGetClassDevs(guid, NULL, NULL, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);

    if (hDevInfo == INVALID_HANDLE_VALUE)   {
        return 0;
    }

    // Retrieve a context structure for a device interface of a device information set
    DWORD dwIndex = 0;
    long res;

    BYTE Buf[1024];
    PSP_DEVICE_INTERFACE_DETAIL_DATA pspdidd = (PSP_DEVICE_INTERFACE_DETAIL_DATA)Buf;
    SP_DEVICE_INTERFACE_DATA         spdid;
    SP_DEVINFO_DATA                  spdd;
    DWORD                            dwSize;

    spdid.cbSize = sizeof(spdid);

    while ( true )  {
        res = SetupDiEnumDeviceInterfaces(hDevInfo, NULL, guid, dwIndex, &spdid);
        if ( !res ) {
            break;
        }

        dwSize = 0;
        SetupDiGetDeviceInterfaceDetail(hDevInfo, &spdid, NULL, 0, &dwSize, NULL); // check the buffer size

        if ( dwSize!=0 && dwSize<=sizeof(Buf) ) {

            pspdidd->cbSize = sizeof(*pspdidd); // 5 Bytes!

            ZeroMemory(&spdd, sizeof(spdd));
            spdd.cbSize = sizeof(spdd);

            long res = SetupDiGetDeviceInterfaceDetail(hDevInfo, &spdid, pspdidd, dwSize, &dwSize, &spdd);
            if ( res ) {

                // in case you are interested in the USB serial number:
                // the device id string contains the serial number if the device has one,
                // otherwise a generated id that contains the '&' char...
                /*
                DEVINST DevInstParent = 0;
                CM_Get_Parent(&DevInstParent, spdd.DevInst, 0); 
                char szDeviceIdString[MAX_PATH];
                CM_Get_Device_ID(DevInstParent, szDeviceIdString, MAX_PATH, 0);
                printf("DeviceId=%s\n", szDeviceIdString);
                */

                // open the disk or cdrom or floppy
                HANDLE hDrive = CreateFile(pspdidd->DevicePath, 0, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
                if ( hDrive != INVALID_HANDLE_VALUE ) {
                    // get its device number
                    STORAGE_DEVICE_NUMBER sdn;
                    DWORD dwBytesReturned = 0;
                    res = DeviceIoControl(hDrive, IOCTL_STORAGE_GET_DEVICE_NUMBER, NULL, 0, &sdn, sizeof(sdn), &dwBytesReturned, NULL);
                    if ( res ) {
                        if ( DeviceNumber == (long)sdn.DeviceNumber ) {  // match the given device number with the one of the current device
                            CloseHandle(hDrive);
                            SetupDiDestroyDeviceInfoList(hDevInfo);
                            return spdd.DevInst;
                        }
                    }
                    CloseHandle(hDrive);
                }
            }
        }
        dwIndex++;
    }

    SetupDiDestroyDeviceInfoList(hDevInfo);

    return 0;
}
//-----------------------------------------------------------

The program returns:

array(2) ( [0] => (string) D:\D:\.\D:failed [1] => (string) Result=0x33 )

Somebody a suggestion?

Answer 1

First run the command through the php client (from shell).

<?php
exec("/path/to/my/program.exe and-parameters");

.

$ php.exe -f file.php //Check link above. I am used to Linux and you might need diffrent params

If that works, then it is most likely an iis permission problem.