source: vbox/trunk/src/VBox/Main/linux/HostHardwareLinux.cpp@ 28576

/* $Id: HostHardwareLinux.cpp 28576 2010-04-21 21:12:39Z vboxsync $ */
/** @file
 * Classes for handling hardware detection under Linux.  Please feel free to
 * expand these to work for other systems (Solaris!) or to add new ones for
 * other systems.
 */

/*
 * Copyright (C) 2008 Sun Microsystems, Inc.
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 USA or visit http://www.sun.com if you need
 * additional information or have any questions.
 */

#define LOG_GROUP LOG_GROUP_MAIN

/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/

#include <HostHardwareLinux.h>

#include <VBox/err.h>
#include <VBox/log.h>

#ifdef VBOX_WITH_DBUS
# include <VBox/dbus.h>
#endif

#include <iprt/dir.h>
#include <iprt/env.h>
#include <iprt/file.h>
#include <iprt/mem.h>
#include <iprt/param.h>
#include <iprt/path.h>
#include <iprt/pipe.h>
#include <iprt/poll.h>
#include <iprt/socket.h>
#include <iprt/string.h>
#include <iprt/thread.h>  /* for RTThreadSleep() */

#include <linux/cdrom.h>
#include <linux/fd.h>
#include <linux/major.h>
#include <scsi/scsi.h>

#include <iprt/linux/sysfs.h>

#ifdef VBOX_USB_WITH_SYSFS
# include <fam.h>
#endif

#include <vector>

#include <errno.h>

/******************************************************************************
*   Global Variables                                                          *
******************************************************************************/

#ifdef TESTCASE
static bool testing() { return true; }
static bool fNoProbe = false;
static bool noProbe() { return fNoProbe; }
static void setNoProbe(bool val) { fNoProbe = val; }
#else
static bool testing() { return false; }
static bool noProbe() { return false; }
static void setNoProbe(bool val) { (void)val; }
#endif

/******************************************************************************
*   Typedefs and Defines                                                      *
******************************************************************************/

/** When waiting for hotplug events, we currently restart the wait after at
 * most this many milliseconds. */
enum { DBUS_POLL_TIMEOUT = 2000 /* ms */ };

static int getDriveInfoFromEnv(const char *pcszVar, DriveInfoList *pList,
                               bool isDVD, bool *pfSuccess);
static int getDriveInfoFromDev(DriveInfoList *pList, bool isDVD,
                               bool *pfSuccess);
static int getDriveInfoFromSysfs(DriveInfoList *pList, bool isDVD,
                                 bool *pfSuccess);
#ifdef VBOX_USB_WITH_SYSFS
static int getUSBDeviceInfoFromSysfs(USBDeviceInfoList *pList, bool *pfSuccess);
# ifdef VBOX_WITH_DBUS
/* These must be extern to be usable in the RTMemAutoPtr template */
extern void VBoxHalShutdown (DBusConnection *pConnection);
extern void VBoxHalShutdownPrivate (DBusConnection *pConnection);
extern void VBoxDBusConnectionUnref(DBusConnection *pConnection);
extern void VBoxDBusConnectionCloseAndUnref(DBusConnection *pConnection);
extern void VBoxDBusMessageUnref(DBusMessage *pMessage);

static int halInit(RTMemAutoPtr <DBusConnection, VBoxHalShutdown> *pConnection);
static int halInitPrivate(RTMemAutoPtr <DBusConnection, VBoxHalShutdownPrivate> *pConnection);
static int halFindDeviceStringMatch (DBusConnection *pConnection,
                                     const char *pszKey, const char *pszValue,
                                     RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> *pMessage);
/*
static int halFindDeviceStringMatchVector (DBusConnection *pConnection,
                                           const char *pszKey,
                                           const char *pszValue,
                                           std::vector<iprt::MiniString> *pMatches);
*/
static int halGetPropertyStrings (DBusConnection *pConnection,
                                  const char *pszUdi, size_t cKeys,
                                  const char **papszKeys, char **papszValues,
                                  RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> *pMessage);
/*
static int halGetPropertyStringsVector (DBusConnection *pConnection,
                                        const char *pszUdi, size_t cProps,
                                        const char **papszKeys,
                                        std::vector<iprt::MiniString> *pMatches,
                                        bool *pfMatches, bool *pfSuccess);
*/
static int getUSBDeviceInfoFromHal(USBDeviceInfoList *pList, bool *pfSuccess);
static int getOldUSBDeviceInfoFromHal(USBDeviceInfoList *pList, bool *pfSuccess);
static int getUSBInterfacesFromHal(std::vector <iprt::MiniString> *pList,
                                   const char *pcszUdi, bool *pfSuccess);
static DBusHandlerResult dbusFilterFunction (DBusConnection *pConnection,
                                             DBusMessage *pMessage, void *pvUser);
# endif  /* VBOX_WITH_DBUS */
#endif /* VBOX_USB_WITH_SYSFS */


/** Find the length of a string, ignoring trailing non-ascii or control
 * characters */
static size_t strLenStripped(const char *pcsz)
{
    size_t cch = 0;
    for (size_t i = 0; pcsz[i] != '\0'; ++i)
        if (pcsz[i] > 32 && pcsz[i] < 127)
            cch = i;
    return cch + 1;
}


/**
 * Get the name of a floppy drive according to the Linux floppy driver.
 * @returns true on success, false if the name was not available (i.e. the
 *          device was not readible, or the file name wasn't a PC floppy
 *          device)
 * @param  pcszNode  the path to the device node for the device
 * @param  Number    the Linux floppy driver number for the drive.  Required.
 * @param  pszName   where to store the name retreived
 */
static bool floppyGetName(const char *pcszNode, unsigned Number,
                          floppy_drive_name pszName)
{
    AssertPtrReturn(pcszNode, false);
    AssertPtrReturn(pszName, false);
    AssertReturn(Number <= 7, false);
    RTFILE File;
    int rc = RTFileOpen(&File, pcszNode, RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_NON_BLOCK);
    if (RT_SUCCESS(rc))
    {
        int rcIoCtl;
        /** @todo The next line can produce a warning, as the ioctl request
         * field is defined as signed, but the Linux ioctl definition macros
         * produce unsigned constants. */
        rc = RTFileIoCtl(File, FDGETDRVTYP, pszName, 0, &rcIoCtl);
        RTFileClose(File);
        if (RT_SUCCESS(rc) && rcIoCtl >= 0)
            return true;
    }
    return false;
}


/**
 * Create a UDI and a description for a floppy drive based on a number and the
 * driver's name for it.  We deliberately return an ugly sequence of
 * characters as the description rather than an English language string to
 * avoid translation issues.
 *
 * @returns true if we know the device to be valid, false otherwise
 * @param   pcszName     the floppy driver name for the device (optional)
 * @param   Number       the number of the floppy (0 to 3 on FDC 0, 4 to 7 on
 *                       FDC 1)
 * @param   pszDesc      where to store the device description (optional)
 * @param   cchDesc      the size of the buffer in @a pszDesc
 * @param   pszUdi       where to store the device UDI (optional)
 * @param   cchUdi       the size of the buffer in @a pszUdi
 */
static void floppyCreateDeviceStrings(const floppy_drive_name pcszName,
                                      unsigned Number, char *pszDesc,
                                      size_t cchDesc, char *pszUdi,
                                      size_t cchUdi)
{
    AssertPtrNullReturnVoid(pcszName);
    AssertPtrNullReturnVoid(pszDesc);
    AssertReturnVoid(!pszDesc || cchDesc > 0);
    AssertPtrNullReturnVoid(pszUdi);
    AssertReturnVoid(!pszUdi || cchUdi > 0);
    AssertReturnVoid(Number <= 7);
    if (pcszName)
    {
        const char *pcszSize;
        switch(pcszName[0])
        {
            case 'd': case 'q': case 'h':
                pcszSize = "5.25\"";
                break;
            case 'D': case 'H': case 'E': case 'u':
                pcszSize = "3.5\"";
                break;
            default:
                pcszSize = "(unknown)";
        }
        if (pszDesc)
            RTStrPrintf(pszDesc, cchDesc, "%s %s K%s", pcszSize, &pcszName[1],
                        Number > 3 ? ", FDC 2" : "");
    }
    else
    {
        if (pszDesc)
            RTStrPrintf(pszDesc, cchDesc, "FDD %d%s", (Number & 4) + 1,
                        Number > 3 ? ", FDC 2" : "");
    }
    if (pszUdi)
        RTStrPrintf(pszUdi, cchUdi,
                    "/org/freedesktop/Hal/devices/platform_floppy_%u_storage",
                    Number);
}


/**
 * Check whether a device number might correspond to a CD-ROM device according
 * to Documentation/devices.txt in the Linux kernel source.
 * @returns true if it might, false otherwise
 * @param   Number  the device number (major and minor combination)
 */
static bool isCdromDevNum(dev_t Number)
{
    int major = major(Number);
    int minor = minor(Number);
    if ((major == IDE0_MAJOR) && !(minor & 0x3f))
        return true;
    if (major == SCSI_CDROM_MAJOR)
        return true;
    if (major == CDU31A_CDROM_MAJOR)
        return true;
    if (major == GOLDSTAR_CDROM_MAJOR)
        return true;
    if (major == OPTICS_CDROM_MAJOR)
        return true;
    if (major == SANYO_CDROM_MAJOR)
        return true;
    if (major == MITSUMI_X_CDROM_MAJOR)
        return true;
    if ((major == IDE1_MAJOR) && !(minor & 0x3f))
        return true;
    if (major == MITSUMI_CDROM_MAJOR)
        return true;
    if (major == CDU535_CDROM_MAJOR)
        return true;
    if (major == MATSUSHITA_CDROM_MAJOR)
        return true;
    if (major == MATSUSHITA_CDROM2_MAJOR)
        return true;
    if (major == MATSUSHITA_CDROM3_MAJOR)
        return true;
    if (major == MATSUSHITA_CDROM4_MAJOR)
        return true;
    if (major == AZTECH_CDROM_MAJOR)
        return true;
    if (major == 30 /* CM205_CDROM_MAJOR */)  /* no #define for some reason */
        return true;
    if (major == CM206_CDROM_MAJOR)
        return true;
    if ((major == IDE3_MAJOR) && !(minor & 0x3f))
        return true;
    if (major == 46 /* Parallel port ATAPI CD-ROM */)  /* no #define */
        return true;
    if ((major == IDE4_MAJOR) && !(minor & 0x3f))
        return true;
    if ((major == IDE5_MAJOR) && !(minor & 0x3f))
        return true;
    if ((major == IDE6_MAJOR) && !(minor & 0x3f))
        return true;
    if ((major == IDE7_MAJOR) && !(minor & 0x3f))
        return true;
    if ((major == IDE8_MAJOR) && !(minor & 0x3f))
        return true;
    if ((major == IDE9_MAJOR) && !(minor & 0x3f))
        return true;
    if (major == 113 /* VIOCD_MAJOR */)
        return true;
    return false;
}


/**
 * Send an SCSI INQUIRY command to a device and return selected information.
 * @returns  iprt status code
 * @returns  VERR_TRY_AGAIN if the query failed but might succeed next time
 * @param pcszNode    the full path to the device node
 * @param pu8Type    where to store the SCSI device type on success (optional)
 * @param pchVendor  where to store the vendor id string on success (optional)
 * @param cchVendor  the size of the @a pchVendor buffer
 * @param pchModel   where to store the product id string on success (optional)
 * @param cchModel   the size of the @a pchModel buffer
 * @note check documentation on the SCSI INQUIRY command and the Linux kernel
 *       SCSI headers included above if you want to understand what is going
 *       on in this method.
 */
static int cdromDoInquiry(const char *pcszNode, uint8_t *pu8Type,
                          char *pchVendor, size_t cchVendor, char *pchModel,
                          size_t cchModel)
{
    LogRelFlowFunc(("pcszNode=%s, pu8Type=%p, pchVendor=%p, cchVendor=%llu, pchModel=%p, cchModel=%llu\n",
                    pcszNode, pu8Type, pchVendor, cchVendor, pchModel,
                    cchModel));
    AssertPtrReturn(pcszNode, VERR_INVALID_POINTER);
    AssertPtrNullReturn(pu8Type, VERR_INVALID_POINTER);
    AssertPtrNullReturn(pchVendor, VERR_INVALID_POINTER);
    AssertPtrNullReturn(pchModel, VERR_INVALID_POINTER);

    RTFILE hFile;
    int rc = RTFileOpen(&hFile, pcszNode, RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_NON_BLOCK);
    if (RT_SUCCESS(rc))
    {
        int                             rcIoCtl        = 0;
        unsigned char                   u8Response[96] = { 0 };
        struct cdrom_generic_command    CdromCommandReq;
        RT_ZERO(CdromCommandReq);
        CdromCommandReq.cmd[0]         = INQUIRY;
        CdromCommandReq.cmd[4]         = sizeof(u8Response);
        CdromCommandReq.buffer         = u8Response;
        CdromCommandReq.buflen         = sizeof(u8Response);
        CdromCommandReq.data_direction = CGC_DATA_READ;
        CdromCommandReq.timeout        = 5000;  /* ms */
        rc = RTFileIoCtl(hFile, CDROM_SEND_PACKET, &CdromCommandReq, 0, &rcIoCtl);
        if (RT_SUCCESS(rc) && rcIoCtl < 0)
            rc = RTErrConvertFromErrno(-CdromCommandReq.stat);
        RTFileClose(hFile);

        if (RT_SUCCESS(rc))
        {
            if (pu8Type)
                *pu8Type = u8Response[0] & 0x1f;
            if (pchVendor)
                RTStrPrintf(pchVendor, cchVendor, "%.8s",
                            &u8Response[8] /* vendor id string */);
            if (pchModel)
                RTStrPrintf(pchModel, cchModel, "%.16s",
                            &u8Response[16] /* product id string */);
            LogRelFlowFunc(("returning success: type=%u, vendor=%.8s, product=%.16s\n",
                            u8Response[0] & 0x1f, &u8Response[8], &u8Response[16]));
            return VINF_SUCCESS;
        }
    }
    LogRelFlowFunc(("returning %Rrc\n", rc));
    return rc;
}


/**
 * Initialise the device strings (description and UDI) for a DVD drive based on
 * vendor and model name strings.
 * @param pcszVendor  the vendor ID string
 * @param pcszModel   the product ID string
 * @param pszDesc    where to store the description string (optional)
 * @param cchDesc    the size of the buffer in @pszDesc
 * @param pszUdi     where to store the UDI string (optional)
 * @param cchUdi     the size of the buffer in @pszUdi
 */
/* static */
void dvdCreateDeviceStrings(const char *pcszVendor, const char *pcszModel,
                            char *pszDesc, size_t cchDesc, char *pszUdi,
                            size_t cchUdi)
{
    AssertPtrReturnVoid(pcszVendor);
    AssertPtrReturnVoid(pcszModel);
    AssertPtrNullReturnVoid(pszDesc);
    AssertReturnVoid(!pszDesc || cchDesc > 0);
    AssertPtrNullReturnVoid(pszUdi);
    AssertReturnVoid(!pszUdi || cchUdi > 0);
    char szCleaned[128];
    size_t cchVendor = strLenStripped(pcszVendor);
    size_t cchModel = strLenStripped(pcszModel);

    /* Create a cleaned version of the model string for the UDI string. */
    for (unsigned i = 0; pcszModel[i] != '\0' && i < sizeof(szCleaned); ++i)
        if (   (pcszModel[i] >= '0' && pcszModel[i] <= '9')
            || (pcszModel[i] >= 'A' && pcszModel[i] <= 'z'))
            szCleaned[i] = pcszModel[i];
        else
            szCleaned[i] = '_';
    szCleaned[RT_MIN(cchModel, sizeof(szCleaned) - 1)] = '\0';

    /* Construct the description string as "Vendor Product" */
    if (pszDesc)
    {
        if (cchVendor > 0)
            RTStrPrintf(pszDesc, cchDesc, "%.*s %s", cchVendor, pcszVendor,
                        cchModel > 0 ? pcszModel : "(unknown drive model)");
        else
            RTStrPrintf(pszDesc, cchDesc, "%s", pcszModel);
    }
    /* Construct the UDI string */
    if (pszUdi)
    {
        if (cchModel > 0)
            RTStrPrintf(pszUdi, cchUdi,
                        "/org/freedesktop/Hal/devices/storage_model_%s",
                        szCleaned);
        else
            pszUdi[0] = '\0';
    }
}


/**
 * Check whether a device node points to a valid device and create a UDI and
 * a description for it, and store the device number, if it does.
 * @returns true if the device is valid, false otherwise
 * @param   pcszNode   the path to the device node
 * @param   isDVD     are we looking for a DVD device (or a floppy device)?
 * @param   pDevice   where to store the device node (optional)
 * @param   pszDesc   where to store the device description (optional)
 * @param   cchDesc   the size of the buffer in @a pszDesc
 * @param   pszUdi    where to store the device UDI (optional)
 * @param   cchUdi    the size of the buffer in @a pszUdi
 */
static bool devValidateDevice(const char *pcszNode, bool isDVD, dev_t *pDevice,
                              char *pszDesc, size_t cchDesc, char *pszUdi,
                              size_t cchUdi)
{
    AssertPtrReturn(pcszNode, false);
    AssertPtrNullReturn(pDevice, false);
    AssertPtrNullReturn(pszDesc, false);
    AssertReturn(!pszDesc || cchDesc > 0, false);
    AssertPtrNullReturn(pszUdi, false);
    AssertReturn(!pszUdi || cchUdi > 0, false);
    RTFSOBJINFO ObjInfo;
    if (RT_FAILURE(RTPathQueryInfo(pcszNode, &ObjInfo, RTFSOBJATTRADD_UNIX)))
        return false;
    if (!RTFS_IS_DEV_BLOCK(ObjInfo.Attr.fMode))
        return false;
    if (pDevice)
        *pDevice = ObjInfo.Attr.u.Unix.Device;
    if (isDVD)
    {
        char szVendor[128], szModel[128];
        uint8_t u8Type;
        if (!isCdromDevNum(ObjInfo.Attr.u.Unix.Device))
            return false;
        if (RT_FAILURE(cdromDoInquiry(pcszNode, &u8Type,
                                      szVendor, sizeof(szVendor),
                                      szModel, sizeof(szModel))))
            return false;
        if (u8Type != TYPE_ROM)
            return false;
        dvdCreateDeviceStrings(szVendor, szModel, pszDesc, cchDesc,
                               pszUdi, cchUdi);
    }
    else
    {
        /* Floppies on Linux are legacy devices with hardcoded majors and
         * minors */
        unsigned Number;
        floppy_drive_name szName;
        if (major(ObjInfo.Attr.u.Unix.Device) != FLOPPY_MAJOR)
            return false;
        switch (minor(ObjInfo.Attr.u.Unix.Device))
        {
            case 0: case 1: case 2: case 3:
                Number = minor(ObjInfo.Attr.u.Unix.Device);
                break;
            case 128: case 129: case 130: case 131:
                Number = minor(ObjInfo.Attr.u.Unix.Device) - 128 + 4;
                break;
            default:
                return false;
        }
        if (!floppyGetName(pcszNode, Number, szName))
            return false;
        floppyCreateDeviceStrings(szName, Number, pszDesc, cchDesc, pszUdi,
                                  cchUdi);
    }
    return true;
}


int VBoxMainDriveInfo::updateDVDs ()
{
    LogFlowThisFunc(("entered\n"));
    int rc = VINF_SUCCESS;
    bool success = false;  /* Have we succeeded in finding anything yet? */
    try
    {
        mDVDList.clear ();
        /* Always allow the user to override our auto-detection using an
         * environment variable. */
        if (RT_SUCCESS(rc) && (!success || testing()))
            rc = getDriveInfoFromEnv ("VBOX_CDROM", &mDVDList, true /* isDVD */,
                                      &success);
        setNoProbe(false);
        if (RT_SUCCESS(rc) && (!success | testing()))
            rc = getDriveInfoFromSysfs(&mDVDList, true /* isDVD */, &success);
        if (RT_SUCCESS(rc) && testing())
        {
            setNoProbe(true);
            rc = getDriveInfoFromSysfs(&mDVDList, true /* isDVD */, &success);
        }
        /* Walk through the /dev subtree if nothing else has helped. */
        if (RT_SUCCESS(rc) && (!success | testing()))
            rc = getDriveInfoFromDev(&mDVDList, true /* isDVD */, &success);
    }
    catch(std::bad_alloc &e)
    {
        rc = VERR_NO_MEMORY;
    }
    LogFlowThisFunc(("rc=%Rrc\n", rc));
    return rc;
}

int VBoxMainDriveInfo::updateFloppies ()
{
    LogFlowThisFunc(("entered\n"));
    int rc = VINF_SUCCESS;
    bool success = false;  /* Have we succeeded in finding anything yet? */
    try
    {
        mFloppyList.clear ();
        if (RT_SUCCESS(rc) && (!success || testing()))
            rc = getDriveInfoFromEnv("VBOX_FLOPPY", &mFloppyList,
                                     false /* isDVD */, &success);
        setNoProbe(false);
        if (   RT_SUCCESS(rc) && (!success || testing()))
            rc = getDriveInfoFromSysfs(&mFloppyList, false /* isDVD */,
                                       &success);
        if (RT_SUCCESS(rc) && testing())
        {
            setNoProbe(true);
            rc = getDriveInfoFromSysfs(&mFloppyList, false /* isDVD */, &success);
        }
        /* Walk through the /dev subtree if nothing else has helped. */
        if (   RT_SUCCESS(rc) && (!success || testing()))
            rc = getDriveInfoFromDev(&mFloppyList, false /* isDVD */,
                                     &success);
    }
    catch(std::bad_alloc &e)
    {
        rc = VERR_NO_MEMORY;
    }
    LogFlowThisFunc(("rc=%Rrc\n", rc));
    return rc;
}


/**
 * Extract the names of drives from an environment variable and add them to a
 * list if they are valid.
 * @returns iprt status code
 * @param   pcszVar     the name of the environment variable.  The variable
 *                     value should be a list of device node names, separated
 *                     by ':' characters.
 * @param   pList      the list to append the drives found to
 * @param   isDVD      are we looking for DVD drives or for floppies?
 * @param   pfSuccess  this will be set to true if we found at least one drive
 *                     and to false otherwise.  Optional.
 */
/* static */
int getDriveInfoFromEnv(const char *pcszVar, DriveInfoList *pList,
                        bool isDVD, bool *pfSuccess)
{
    AssertPtrReturn(pcszVar, VERR_INVALID_POINTER);
    AssertPtrReturn(pList, VERR_INVALID_POINTER);
    AssertPtrNullReturn(pfSuccess, VERR_INVALID_POINTER);
    LogFlowFunc(("pcszVar=%s, pList=%p, isDVD=%d, pfSuccess=%p\n", pcszVar,
                 pList, isDVD, pfSuccess));
    int rc = VINF_SUCCESS;
    bool success = false;
    char *pszFreeMe = RTEnvDupEx(RTENV_DEFAULT, pcszVar);

    try
    {
        const char *pcszCurrent = pszFreeMe;
        while (pcszCurrent && *pcszCurrent != '\0')
        {
            const char *pcszNext = strchr(pcszCurrent, ':');
            char szPath[RTPATH_MAX], szReal[RTPATH_MAX];
            char szDesc[256], szUdi[256];
            if (pcszNext)
                RTStrPrintf(szPath, sizeof(szPath), "%.*s",
                            pcszNext - pcszCurrent - 1, pcszCurrent);
            else
                RTStrPrintf(szPath, sizeof(szPath), "%s", pcszCurrent);
            if (   RT_SUCCESS(RTPathReal(szPath, szReal, sizeof(szReal)))
                && devValidateDevice(szReal, isDVD, NULL, szDesc,
                                     sizeof(szDesc), szUdi, sizeof(szUdi)))
            {
                pList->push_back(DriveInfo(szReal, szUdi, szDesc));
                success = true;
            }
            pcszCurrent = pcszNext ? pcszNext + 1 : NULL;
        }
        if (pfSuccess != NULL)
            *pfSuccess = success;
    }
    catch(std::bad_alloc &e)
    {
        rc = VERR_NO_MEMORY;
    }
    RTStrFree(pszFreeMe);
    LogFlowFunc(("rc=%Rrc, success=%d\n", rc, success));
    return rc;
}


class sysfsBlockDev
{
public:
    sysfsBlockDev(const char *pcszName, bool wantDVD)
            : mpcszName(pcszName), mwantDVD(wantDVD), misConsistent(true),
              misValid(false)
    {
        if (findDeviceNode())
        {
            if (mwantDVD)
                validateAndInitForDVD();
            else
                validateAndInitForFloppy();
        }
    }
private:
    /** The name of the subdirectory of /sys/block for this device */
    const char *mpcszName;
    /** Are we looking for a floppy or a DVD device? */
    bool mwantDVD;
    /** The device node for the device */
    char mszNode[RTPATH_MAX];
    /** Does the sysfs entry look like we expect it too?  This is a canary
     * for future sysfs ABI changes. */
    bool misConsistent;
    /** Is this entry a valid specimen of what we are looking for? */
    bool misValid;
    /** Human readible drive description string */
    char mszDesc[256];
    /** Unique identifier for the drive.  Should be identical to hal's UDI for
     * the device.  May not be unique for two identical drives. */
    char mszUdi[256];
private:
    /* Private methods */

    /**
     * Fill in the device node member based on the /sys/block subdirectory.
     * @returns boolean success value
     */
    bool findDeviceNode()
    {
        dev_t dev = RTLinuxSysFsReadDevNumFile("block/%s/dev", mpcszName);
        if (dev == 0)
        {
            misConsistent = false;
            return false;
        }
        if (RTLinuxFindDevicePath(dev, RTFS_TYPE_DEV_BLOCK, mszNode,
                                  sizeof(mszNode), "%s", mpcszName) < 0)
            return false;
        return true;
    }

    /** Check whether the sysfs block entry is valid for a DVD device and
     * initialise the string data members for the object.  We try to get all
     * the information we need from sysfs if possible, to avoid unnecessarily
     * poking the device, and if that fails we fall back to an SCSI INQUIRY
     * command. */
    void validateAndInitForDVD()
    {
        char szVendor[128], szModel[128];
        ssize_t cchVendor, cchModel;
        int64_t type = RTLinuxSysFsReadIntFile(10, "block/%s/device/type",
                                               mpcszName);
        if (type >= 0 && type != TYPE_ROM)
            return;
        if (type == TYPE_ROM)
        {
            cchVendor = RTLinuxSysFsReadStrFile(szVendor, sizeof(szVendor),
                                                "block/%s/device/vendor",
                                                mpcszName);
            if (cchVendor >= 0)
            {
                cchModel = RTLinuxSysFsReadStrFile(szModel, sizeof(szModel),
                                                   "block/%s/device/model",
                                                   mpcszName);
                if (cchModel >= 0)
                {
                    misValid = true;
                    dvdCreateDeviceStrings(szVendor, szModel,
                                           mszDesc, sizeof(mszDesc),
                                           mszUdi, sizeof(mszUdi));
                    return;
                }
            }
        }
        if (!noProbe())
            probeAndInitForDVD();
    }

    /** Try to find out whether a device is a DVD drive by sending it an
     * SCSI INQUIRY command.  If it is, initialise the string and validity
     * data members for the object based on the returned data.
     */
    void probeAndInitForDVD()
    {
        AssertReturnVoid(mszNode[0] != '\0');
        uint8_t u8Type = 0;
        char szVendor[128] = "";
        char szModel[128] = "";
        int rc = cdromDoInquiry(mszNode, &u8Type, szVendor,
                                sizeof(szVendor), szModel,
                                sizeof(szModel));
        if (RT_SUCCESS(rc) && (u8Type == TYPE_ROM))
        {
            misValid = true;
            dvdCreateDeviceStrings(szVendor, szModel, mszDesc, sizeof(mszDesc),
                                   mszUdi, sizeof(mszUdi));
        }
    }

    /** Check whether the sysfs block entry is valid for a floppy device and
     * initialise the string data members for the object.  Since we only
     * support floppies using the basic "floppy" driver, we check the driver
     * using the entry name and a driver-specific ioctl. */
    void validateAndInitForFloppy()
    {
        bool haveName = false;
        floppy_drive_name szName;
        char szDriver[8];
        if (   mpcszName[0] != 'f'
            || mpcszName[1] != 'd'
            || mpcszName[2] < '0'
            || mpcszName[2] > '7'
            || mpcszName[3] != '\0')
            return;
        if (!noProbe())
            haveName = floppyGetName(mszNode, mpcszName[2] - '0', szName);
        if (RTLinuxSysFsGetLinkDest(szDriver, sizeof(szDriver), "block/%s/%s",
                                    mpcszName, "device/driver") >= 0)
        {
            if (RTStrCmp(szDriver, "floppy"))
                return;
        }
        else if (!haveName)
            return;
        floppyCreateDeviceStrings(haveName ? szName : NULL,
                                  mpcszName[2] - '0', mszDesc,
                                  sizeof(mszDesc), mszUdi, sizeof(mszUdi));
        misValid = true;
    }

public:
    bool isConsistent()
    {
        return misConsistent;
    }
    bool isValid()
    {
        return misValid;
    }
    const char *getDesc()
    {
        return mszDesc;
    }
    const char *getUdi()
    {
        return mszUdi;
    }
    const char *getNode()
    {
        return mszNode;
    }
};

/**
 * Helper function to query the sysfs subsystem for information about DVD
 * drives attached to the system.
 * @returns iprt status code
 * @param   pList      where to add information about the drives detected
 * @param   isDVD      are we looking for DVDs or floppies?
 * @param   pfSuccess  Did we find anything?
 *
 * @returns IPRT status code
 */
/* static */
int getDriveInfoFromSysfs(DriveInfoList *pList, bool isDVD, bool *pfSuccess)
{
    AssertPtrReturn(pList, VERR_INVALID_POINTER);
    AssertPtrNullReturn(pfSuccess, VERR_INVALID_POINTER); /* Valid or Null */
    LogFlowFunc (("pList=%p, isDVD=%u, pfSuccess=%p\n",
                  pList, (unsigned) isDVD, pfSuccess));
    PRTDIR pDir = NULL;
    int rc;
    bool fSuccess = false;
    unsigned cFound = 0;

    if (!RTPathExists("/sys"))
        return VINF_SUCCESS;
    rc = RTDirOpen(&pDir, "/sys/block");
    /* This might mean that sysfs semantics have changed */
    AssertReturn(rc != VERR_FILE_NOT_FOUND, VINF_SUCCESS);
    fSuccess = true;
    if (RT_SUCCESS(rc))
        for (;;)
        {
            RTDIRENTRY entry;
            rc = RTDirRead(pDir, &entry, NULL);
            Assert(rc != VERR_BUFFER_OVERFLOW);  /* Should never happen... */
            if (RT_FAILURE(rc))  /* Including overflow and no more files */
                break;
            if (entry.szName[0] == '.')
                continue;
            sysfsBlockDev dev(entry.szName, isDVD);
            /* This might mean that sysfs semantics have changed */
            AssertBreakStmt(dev.isConsistent(), fSuccess = false);
            if (!dev.isValid())
                continue;
            try
            {
                pList->push_back(DriveInfo(dev.getNode(), dev.getUdi(),
                                           dev.getDesc()));
            }
            catch(std::bad_alloc &e)
            {
                rc = VERR_NO_MEMORY;
                break;
            }
            ++cFound;
        }
    RTDirClose(pDir);
    if (rc == VERR_NO_MORE_FILES)
        rc = VINF_SUCCESS;
    if (RT_FAILURE(rc))
        /* Clean up again */
        for (unsigned i = 0; i < cFound; ++i)
            pList->pop_back();
    if (pfSuccess)
        *pfSuccess = fSuccess;
    LogFlow (("rc=%Rrc, fSuccess=%u\n", rc, (unsigned) fSuccess));
    return rc;
}


/** Structure for holding information about a drive we have found */
struct deviceNodeInfo
{
    /** The device number */
    dev_t Device;
    /** The device node path */
    char szPath[RTPATH_MAX];
    /** The device description */
    char szDesc[256];
    /** The device UDI */
    char szUdi[256];
};

/** The maximum number of devices we will search for. */
enum { MAX_DEVICE_NODES = 8 };
/** An array of MAX_DEVICE_NODES devices */
typedef struct deviceNodeInfo deviceNodeArray[MAX_DEVICE_NODES];

/**
 * Recursive worker function to walk the /dev tree looking for DVD or floppy
 * devices.
 * @returns true if we have already found MAX_DEVICE_NODES devices, false
 *          otherwise
 * @param   pszPath   the path to start recursing.  The function can modify
 *                    this string at and after the terminating zero
 * @param   cchPath   the size of the buffer (not the string!) in @a pszPath
 * @param   aDevices  where to fill in information about devices that we have
 *                    found
 * @param   wantDVD   are we looking for DVD devices (or floppies)?
 */
static bool devFindDeviceRecursive(char *pszPath, size_t cchPath,
                                   deviceNodeArray aDevices, bool wantDVD)
{
    /*
     * Check assumptions made by the code below.
     */
    size_t const cchBasePath = strlen(pszPath);
    AssertReturn(cchBasePath < RTPATH_MAX - 10U, false);
    AssertReturn(pszPath[cchBasePath - 1] != '/', false);

    PRTDIR  pDir;
    if (RT_FAILURE(RTDirOpen(&pDir, pszPath)))
        return false;
    for (;;)
    {
        RTDIRENTRY Entry;
        RTFSOBJINFO ObjInfo;
        int rc = RTDirRead(pDir, &Entry, NULL);
        if (RT_FAILURE(rc))
            break;
        if (Entry.enmType == RTDIRENTRYTYPE_UNKNOWN)
        {
            if (RT_FAILURE(RTPathQueryInfo(pszPath, &ObjInfo,
                           RTFSOBJATTRADD_UNIX)))
                continue;
            if (RTFS_IS_SYMLINK(ObjInfo.Attr.fMode))
                continue;
        }

        if (Entry.enmType == RTDIRENTRYTYPE_SYMLINK)
            continue;
        pszPath[cchBasePath] = '\0';
        if (RT_FAILURE(RTPathAppend(pszPath, cchPath, Entry.szName)))
            break;

        /* Do the matching. */
        dev_t DevNode;
        char szDesc[256], szUdi[256];
        if (!devValidateDevice(pszPath, wantDVD, &DevNode, szDesc,
                               sizeof(szDesc), szUdi, sizeof(szUdi)))
            continue;
        unsigned i;
        for (i = 0; i < MAX_DEVICE_NODES; ++i)
            if (!aDevices[i].Device || (aDevices[i].Device == DevNode))
                break;
        AssertBreak(i < MAX_DEVICE_NODES);
        if (aDevices[i].Device)
            continue;
        aDevices[i].Device = DevNode;
        RTStrPrintf(aDevices[i].szPath, sizeof(aDevices[i].szPath),
                    "%s", pszPath);
        AssertCompile(sizeof(aDevices[i].szDesc) == sizeof(szDesc));
        strcpy(aDevices[i].szDesc, szDesc);
        AssertCompile(sizeof(aDevices[i].szUdi) == sizeof(szUdi));
        strcpy(aDevices[i].szUdi, szUdi);
        if (i == MAX_DEVICE_NODES - 1)
            break;
        continue;

        /* Recurse into subdirectories. */
        if (   (Entry.enmType == RTDIRENTRYTYPE_UNKNOWN)
            && !RTFS_IS_DIRECTORY(ObjInfo.Attr.fMode))
            continue;
        if (Entry.enmType != RTDIRENTRYTYPE_DIRECTORY)
            continue;
        if (Entry.szName[0] == '.')
            continue;

        if (devFindDeviceRecursive(pszPath, cchPath, aDevices, wantDVD))
            break;
    }
    RTDirClose(pDir);
    return aDevices[MAX_DEVICE_NODES - 1].Device ? true : false;
}


/**
 * Recursively walk through the /dev tree and add any DVD or floppy drives we
 * find and can access to our list.  (If we can't access them we can't check
 * whether or not they are really DVD or floppy drives).
 * @note  this is rather slow (a couple of seconds) for DVD probing on
 *        systems with a static /dev tree, as the current code tries to open
 *        any device node with a major/minor combination that could belong to
 *        a CD-ROM device, and opening a non-existent device can take a non.
 *        negligeable time on Linux.  If it is ever necessary to improve this
 *        (static /dev trees are no longer very fashionable these days, and
 *        sysfs looks like it will be with us for a while), we could further
 *        reduce the number of device nodes we open by checking whether the
 *        driver is actually loaded in /proc/devices, and by counting the
 *        of currently attached SCSI CD-ROM devices in /proc/scsi/scsi (yes,
 *        there is a race, but it is probably not important for us).
 * @returns iprt status code
 * @param   pList      the list to append the drives found to
 * @param   isDVD      are we looking for DVD drives or for floppies?
 * @param   pfSuccess  this will be set to true if we found at least one drive
 *                     and to false otherwise.  Optional.
 */
/* static */
int getDriveInfoFromDev(DriveInfoList *pList, bool isDVD, bool *pfSuccess)
{
    AssertPtrReturn(pList, VERR_INVALID_POINTER);
    AssertPtrNullReturn(pfSuccess, VERR_INVALID_POINTER);
    LogFlowFunc(("pList=%p, isDVD=%d, pfSuccess=%p\n", pList, isDVD,
                 pfSuccess));
    int rc = VINF_SUCCESS;
    bool success = false;

    char szPath[RTPATH_MAX] = "/dev";
    deviceNodeArray aDevices;
    RT_ZERO(aDevices);
    devFindDeviceRecursive(szPath, sizeof(szPath), aDevices, isDVD);
    try
    {
        for (unsigned i = 0; i < MAX_DEVICE_NODES; ++i)
        {
            if (aDevices[i].Device)
            {
                pList->push_back(DriveInfo(aDevices[i].szPath,
                                 aDevices[i].szUdi, aDevices[i].szDesc));
                success = true;
            }
        }
        if (pfSuccess != NULL)
            *pfSuccess = success;
    }
    catch(std::bad_alloc &e)
    {
        rc = VERR_NO_MEMORY;
    }
    LogFlowFunc (("rc=%Rrc, success=%d\n", rc, success));
    return rc;
}


int VBoxMainUSBDeviceInfo::UpdateDevices ()
{
    LogFlowThisFunc(("entered\n"));
    int rc = VINF_SUCCESS;
    bool success = false;  /* Have we succeeded in finding anything yet? */
    try
    {
        mDeviceList.clear();
#ifdef VBOX_USB_WITH_SYSFS
# ifdef VBOX_WITH_DBUS
        bool halSuccess = false;
        if (   RT_SUCCESS(rc)
            && RT_SUCCESS(RTDBusLoadLib())
            && (!success || testing()))
            rc = getUSBDeviceInfoFromHal(&mDeviceList, &halSuccess);
        /* Try the old API if the new one *succeeded* as only one of them will
         * pick up devices anyway. */
        if (RT_SUCCESS(rc) && halSuccess && (!success || testing()))
            rc = getOldUSBDeviceInfoFromHal(&mDeviceList, &halSuccess);
        if (!success)
            success = halSuccess;
# endif /* VBOX_WITH_DBUS */
        if (   RT_SUCCESS(rc)
            && (!success || testing()))
            rc = getUSBDeviceInfoFromSysfs(&mDeviceList, &success);
#else /* !VBOX_USB_WITH_SYSFS */
        NOREF(success);
#endif /* !VBOX_USB_WITH_SYSFS */
    }
    catch(std::bad_alloc &e)
    {
        rc = VERR_NO_MEMORY;
    }
    LogFlowThisFunc(("rc=%Rrc\n", rc));
    return rc;
}

#if defined VBOX_USB_WITH_SYSFS && defined VBOX_WITH_DBUS
class hotplugDBusImpl : public VBoxMainHotplugWaiterImpl
{
    /** The connection to DBus */
    RTMemAutoPtr <DBusConnection, VBoxHalShutdownPrivate> mConnection;
    /** Semaphore which is set when a device is hotplugged and reset when
     * it is read. */
    volatile bool mTriggered;
    /** A flag to say that we wish to interrupt the current wait. */
    volatile bool mInterrupt;

public:
    /** Test whether this implementation can be used on the current system */
    static bool HalAvailable(void)
    {
        RTMemAutoPtr<DBusConnection, VBoxHalShutdown> dbusConnection;

        /* Try to open a test connection to hal */
        if (RT_SUCCESS(RTDBusLoadLib()) && RT_SUCCESS(halInit (&dbusConnection)))
            return !!dbusConnection;
        return false;
    }

    /** Constructor */
    hotplugDBusImpl (void);
    virtual ~hotplugDBusImpl (void);
    /** @copydoc VBoxMainHotplugWaiter::Wait */
    virtual int Wait (RTMSINTERVAL cMillies);
    /** @copydoc VBoxMainHotplugWaiter::Interrupt */
    virtual void Interrupt (void);
};

/* This constructor sets up a private connection to the DBus daemon, connects
 * to the hal service and installs a filter which sets the mTriggered flag in
 * the Context structure when a device (not necessarily USB) is added or
 * removed. */
hotplugDBusImpl::hotplugDBusImpl (void) : mTriggered(false), mInterrupt(false)
{
    int rc = VINF_SUCCESS;

    if (RT_SUCCESS(RTDBusLoadLib()))
    {
        for (unsigned i = 0; RT_SUCCESS(rc) && i < 5 && !mConnection; ++i)
        {
            rc = halInitPrivate (&mConnection);
        }
        if (!mConnection)
            rc = VERR_NOT_SUPPORTED;
        DBusMessage *pMessage;
        while (   RT_SUCCESS(rc)
               && (pMessage = dbus_connection_pop_message (mConnection.get())) != NULL)
            dbus_message_unref (pMessage); /* empty the message queue. */
        if (   RT_SUCCESS(rc)
            && !dbus_connection_add_filter (mConnection.get(),
                                            dbusFilterFunction,
                                            (void *) &mTriggered, NULL))
            rc = VERR_NO_MEMORY;
        if (RT_FAILURE(rc))
            mConnection.reset();
    }
}

/* Destructor */
hotplugDBusImpl::~hotplugDBusImpl ()
{
    if (!!mConnection)
        dbus_connection_remove_filter (mConnection.get(), dbusFilterFunction,
                                       (void *) &mTriggered);
}

/* Currently this is implemented using a timed out wait on our private DBus
 * connection.  Because the connection is private we don't have to worry about
 * blocking other users. */
int hotplugDBusImpl::Wait(RTMSINTERVAL cMillies)
{
    int rc = VINF_SUCCESS;
    if (!mConnection)
        rc = VERR_NOT_SUPPORTED;
    bool connected = true;
    mTriggered = false;
    mInterrupt = false;
    unsigned cRealMillies;
    if (cMillies != RT_INDEFINITE_WAIT)
        cRealMillies = cMillies;
    else
        cRealMillies = DBUS_POLL_TIMEOUT;
    while (   RT_SUCCESS(rc) && connected && !mTriggered
           && !mInterrupt)
    {
        connected = dbus_connection_read_write_dispatch (mConnection.get(),
                                                         cRealMillies);
        if (mInterrupt)
            LogFlowFunc(("wait loop interrupted\n"));
        if (cMillies != RT_INDEFINITE_WAIT)
            mInterrupt = true;
    }
    if (!connected)
        rc = VERR_TRY_AGAIN;
    return rc;
}

/* Set a flag to tell the Wait not to resume next time it times out. */
void hotplugDBusImpl::Interrupt()
{
    LogFlowFunc(("\n"));
    mInterrupt = true;
}
#endif  /* VBOX_USB_WITH_SYSFS && VBOX_WITH_DBUS */

class hotplugNullImpl : public VBoxMainHotplugWaiterImpl
{
public:
    hotplugNullImpl (void) {}
    virtual ~hotplugNullImpl (void) {}
    /** @copydoc VBoxMainHotplugWaiter::Wait */
    virtual int Wait (RTMSINTERVAL)
    {
        return VERR_NOT_SUPPORTED;
    }
    /** @copydoc VBoxMainHotplugWaiter::Interrupt */
    virtual void Interrupt (void) {}
};

#ifdef VBOX_USB_WITH_SYSFS

#define SYSFS_USB_DEVICE_PATH "/dev/bus/usb"
#define SYSFS_WAKEUP_STRING "Wake up!"

class hotplugSysfsFAMImpl : public VBoxMainHotplugWaiterImpl
{
    /** Pipe used to interrupt wait(), the read end. */
    RTPIPE mhWakeupPipeR;
    /** Pipe used to interrupt wait(), the write end. */
    RTPIPE mhWakeupPipeW;
    /** Our connection to FAM for polling for changes on sysfs. */
    FAMConnection mFAMConnection;
    /** Has our connection been initialised? */
    bool mfFAMInitialised;
    /** The iprt native handle of the FAM fd socket. */
    RTSOCKET mhFAMFD;
    /** Poll set containing the FAM socket and the termination pipe */
    RTPOLLSET mhPollSet;
    /** iprt result code from object initialisation.  Should be AssertReturn-ed
     * on at the start of all methods.  I went this way because I didn't want
     * to deal with exceptions. */
    int mStatus;
    /** ID values associates with the wakeup pipe and the FAM socket for polling
     */
    enum
    {
        RPIPE_ID = 1,
        FAMFD_ID
    };

    /** Clean up any resources in use, gracefully skipping over any which have
     * not yet been allocated or already cleaned up.  Intended to be called
     * from the destructor or after a failed initialisation. */
    void term(void);

    /** Open our connection to FAM and convert the status to iprt.
     * @todo  really convert the status
     */
    int openFAM(void)
    {
        if (FAMOpen(&mFAMConnection) < 0)
            return VERR_FAM_OPEN_FAILED;
        mfFAMInitialised = true;
        return VINF_SUCCESS;
    }

    /** Monitor a file through the FAM connection. */
    int monitorDirectoryFAM(const char *pszName)
    {
        AssertReturn(mfFAMInitialised, VERR_WRONG_ORDER);
        FAMRequest dummyReq;
        if (FAMMonitorDirectory(&mFAMConnection, pszName, &dummyReq, NULL) < 0)
            return VERR_FAM_MONITOR_DIRECTORY_FAILED;
        return VINF_SUCCESS;
    }

    /** Quick failure test of the monitor function - we temporarily invalidate
     * the connection FD to trigger an error path. */
    void testmonitorDirectoryFAM(void)
    {
        int oldFD = FAMCONNECTION_GETFD(&mFAMConnection);
        FAMCONNECTION_GETFD(&mFAMConnection) = -1;
        Assert(monitorDirectoryFAM(NULL) == VERR_FAM_MONITOR_DIRECTORY_FAILED);
        FAMCONNECTION_GETFD(&mFAMConnection) = oldFD;
    }

    /** Close our connection to FAM.  We ignore errors as there is no
     * documentation as to what they mean, and the only error which might
     * interest us (EINTR) should be (but isn't) handled inside the library. */
    void closeFAM(void)
    {
        if (mfFAMInitialised)
            FAMClose(&mFAMConnection);
        mfFAMInitialised = false;
    }

    /** Read the wakeup string from the wakeup pipe */
    int drainWakeupPipe(void);
public:
    hotplugSysfsFAMImpl(void);
    virtual ~hotplugSysfsFAMImpl(void)
    {
        term();
#ifdef DEBUG
        /** The first call to term should mark all resources as freed, so this
         * should be a semantic no-op. */
        term();
#endif
    }
    /** Is sysfs available on this system?  If so we expect that this
     * implementation will be usable. */
    static bool SysfsAvailable(void)
    {
        return RTDirExists(SYSFS_USB_DEVICE_PATH);
    }
    /** @copydoc VBoxMainHotplugWaiter::Wait */
    virtual int Wait(RTMSINTERVAL);
    /** @copydoc VBoxMainHotplugWaiter::Interrupt */
    virtual void Interrupt(void);
};

hotplugSysfsFAMImpl::hotplugSysfsFAMImpl(void) :
    mhWakeupPipeR(NIL_RTPIPE), mhWakeupPipeW(NIL_RTPIPE),
    mfFAMInitialised(false), mhFAMFD(NIL_RTSOCKET), mhPollSet(NIL_RTPOLLSET),
    mStatus(VERR_WRONG_ORDER)
{
#ifdef DEBUG
    /* Excercise the code path (term() on a not-fully-initialised object) as
     * well as we can.  On an uninitialised object this method is a sematic
     * no-op. */
    term();
    /* For now this probing method should only be used if nothing else is
     * available */
    if (!testing())
    {
#ifndef VBOX_USB_WITH_SYSFS_BY_DEFAULT
        Assert(!RTFileExists("/proc/bus/usb/devices"));
#endif
#ifdef VBOX_WITH_DBUS
        Assert(!hotplugDBusImpl::HalAvailable());
#endif
    }
#endif
    int rc;
    do {
        if (RT_FAILURE(rc = RTPipeCreate(&mhWakeupPipeR, &mhWakeupPipeW, 0)))
            break;
        if (RT_FAILURE(rc = openFAM()))
            break;
        if (RT_FAILURE(rc = RTSocketFromNative
                                (&mhFAMFD, FAMCONNECTION_GETFD(&mFAMConnection))))
            break;
        if (RT_FAILURE(rc = monitorDirectoryFAM(SYSFS_USB_DEVICE_PATH)))
            break;
        if (RT_FAILURE(rc = RTPollSetCreate(&mhPollSet)))
            break;
        if (RT_FAILURE(rc = RTPollSetAddSocket
                                (mhPollSet, mhFAMFD, RTPOLL_EVT_READ, FAMFD_ID)))
            break;
        if (RT_FAILURE(rc = RTPollSetAddPipe
                                (mhPollSet, mhWakeupPipeR, RTPOLL_EVT_READ, RPIPE_ID)))
            break;
#ifdef DEBUG
        /** Other tests */
        testmonitorDirectoryFAM();
#endif
    } while(0);
    mStatus = rc;
    if (RT_FAILURE(rc))
        term();
}

void hotplugSysfsFAMImpl::term(void)
{
    RTPipeClose(mhWakeupPipeR);
    mhWakeupPipeR = NIL_RTPIPE;
    RTPipeClose(mhWakeupPipeW);
    mhWakeupPipeW = NIL_RTPIPE;
    closeFAM();
    mhFAMFD = NIL_RTSOCKET;
    RTPollSetDestroy(mhPollSet);
    mhPollSet = NIL_RTPOLLSET;
}

/** Does a FAM event code mean that the available devices have (probably)
 * changed? */
static int sysfsGetStatusForFAMCode(FAMCodes enmCode)
{
    if (enmCode == FAMExists || enmCode == FAMEndExist)
        return VERR_TRY_AGAIN;
    return VINF_SUCCESS;
}

int hotplugSysfsFAMImpl::drainWakeupPipe(void)
{
    char szBuf[sizeof(SYSFS_WAKEUP_STRING)];
    int rc = RTPipeRead(mhWakeupPipeR, szBuf, sizeof(szBuf), NULL);
    AssertRC(rc);
    return VINF_SUCCESS;
}

int hotplugSysfsFAMImpl::Wait(RTMSINTERVAL aMillies)
{
    uint32_t id;
    int rc;
    FAMEvent ev;

    if (RT_FAILURE(mStatus))
        return VERR_NOT_SUPPORTED;
    /* timeout returns */
    if (RT_FAILURE(rc = RTPoll(mhPollSet, aMillies, NULL, &id)))
        return rc;
    if (id == RPIPE_ID)
        return drainWakeupPipe();
    AssertReturn(id == FAMFD_ID, VERR_NOT_SUPPORTED);
    /* Samba re-opens the connection to FAM if this happens. */
    AssertReturn(FAMNextEvent(&mFAMConnection, &ev) == 1,
                 VERR_NOT_SUPPORTED);
    return sysfsGetStatusForFAMCode(ev.code);
}

void hotplugSysfsFAMImpl::Interrupt(void)
{
    size_t cbDummy;
    int rc = RTPipeWrite(mhWakeupPipeW, SYSFS_WAKEUP_STRING,
                         sizeof(SYSFS_WAKEUP_STRING), &cbDummy);
    if (RT_SUCCESS(rc))
        RTPipeFlush(mhWakeupPipeW);
}

#endif  /* VBOX_USB_WTH_SYSFS */

VBoxMainHotplugWaiter::VBoxMainHotplugWaiter(void)
{
#ifdef VBOX_USB_WITH_SYSFS
# ifdef VBOX_WITH_DBUS
    if (hotplugDBusImpl::HalAvailable())
    {
        mImpl = new hotplugDBusImpl;
        return;
    }
# endif  /* VBOX_WITH_DBUS */
    if (hotplugSysfsFAMImpl::SysfsAvailable())
    {
        mImpl = new hotplugSysfsFAMImpl;
        return;
    }
#endif  /* VBOX_USB_WITH_SYSFS */
    mImpl = new hotplugNullImpl;
}

#ifdef VBOX_USB_WITH_SYSFS
class sysfsPathHandler
{
    /** Called on each element of the sysfs directory.  Can e.g. store
     * interesting entries in a list. */
    virtual bool handle(const char *pcszNode) = 0;
public:
    bool doHandle(const char *pcszNode)
    {
        AssertPtr(pcszNode);
        Assert(pcszNode[0] == '/');
        Assert(RTPathExists(pcszNode));
        return handle(pcszNode);
    }
};

/**
 * Helper function to walk a sysfs directory for extracting information about
 * devices.
 * @returns iprt status code
 * @param   pcszPath   Sysfs directory to walk.  Must exist.
 * @param   pHandler   Handler object which will be invoked on each directory
 *                     entry
 *
 * @returns IPRT status code
 */
/* static */
int getDeviceInfoFromSysfs(const char *pcszPath, sysfsPathHandler *pHandler)
{
    AssertPtrReturn(pcszPath, VERR_INVALID_POINTER);
    AssertPtrReturn(pHandler, VERR_INVALID_POINTER);
    LogFlowFunc (("pcszPath=%s, pHandler=%p\n", pcszPath, pHandler));
    PRTDIR pDir = NULL;
    int rc;

    rc = RTDirOpen(&pDir, pcszPath);
    AssertRCReturn(rc, rc);
    while (RT_SUCCESS(rc))
    {
        RTDIRENTRY entry;
        char szPath[RTPATH_MAX], szAbsPath[RTPATH_MAX];

        rc = RTDirRead(pDir, &entry, NULL);
        Assert(rc != VERR_BUFFER_OVERFLOW);  /* Should never happen... */
            /* We break on "no more files" as well as on "real" errors */
        if (RT_FAILURE(rc))
            break;
        if (entry.szName[0] == '.')
            continue;
        if (RTStrPrintf(szPath, sizeof(szPath), "%s/%s", pcszPath,
                        entry.szName) >= sizeof(szPath))
            rc = VERR_BUFFER_OVERFLOW;
        if (RT_FAILURE(rc))
            break;
        rc = RTPathReal(szPath, szAbsPath, sizeof(szAbsPath));
        AssertRCBreak(rc);  /* sysfs should guarantee that this exists */
        if (!pHandler->doHandle(szAbsPath))
            break;
    }
    RTDirClose(pDir);
    if (rc == VERR_NO_MORE_FILES)
        rc = VINF_SUCCESS;
    LogFlow (("rc=%Rrc\n", rc));
    return rc;
}


/**
 * Tell whether a file in /sys/bus/usb/devices is a device rather than an
 * interface.  To be used with getDeviceInfoFromSysfs().
 */
class matchUSBDevice : public sysfsPathHandler
{
    USBDeviceInfoList *mList;
public:
    matchUSBDevice(USBDeviceInfoList *pList) : mList(pList) {}
private:
    virtual bool handle(const char *pcszNode)
    {
        const char *pcszFile = strrchr(pcszNode, '/');
        if (strchr(pcszFile, ':'))
            return true;
        dev_t devnum = RTLinuxSysFsReadDevNumFile("%s/dev", pcszNode);
        AssertReturn (devnum, true);
        char szDevPath[RTPATH_MAX];
        ssize_t cchDevPath;
        cchDevPath = RTLinuxFindDevicePath(devnum, RTFS_TYPE_DEV_CHAR,
                                           szDevPath, sizeof(szDevPath),
                                           "/dev/bus/usb/%.3d/%.3d",
                                           RTLinuxSysFsReadIntFile(10, "%s/busnum", pcszNode),
                                           RTLinuxSysFsReadIntFile(10, "%s/devnum", pcszNode));
        if (cchDevPath < 0)
            return true;
        try
        {
            mList->push_back(USBDeviceInfo(szDevPath, pcszNode));
        }
        catch(std::bad_alloc &e)
        {
            return false;
        }
        return true;
    }
};

/**
 * Tell whether a file in /sys/bus/usb/devices is an interface rather than a
 * device.  To be used with getDeviceInfoFromSysfs().
 */
class matchUSBInterface : public sysfsPathHandler
{
    USBDeviceInfo *mInfo;
public:
    /** This constructor is currently used to unit test the class logic in
     * debug builds.  Since no access is made to anything outside the class,
     * this shouldn't cause any slowdown worth mentioning. */
    matchUSBInterface(USBDeviceInfo *pInfo) : mInfo(pInfo)
    {
        Assert(isAnInterfaceOf("/sys/devices/pci0000:00/0000:00:1a.0/usb3/3-0:1.0",
               "/sys/devices/pci0000:00/0000:00:1a.0/usb3"));
        Assert(!isAnInterfaceOf("/sys/devices/pci0000:00/0000:00:1a.0/usb3/3-1",
               "/sys/devices/pci0000:00/0000:00:1a.0/usb3"));
        Assert(!isAnInterfaceOf("/sys/devices/pci0000:00/0000:00:1a.0/usb3/3-0:1.0/driver",
               "/sys/devices/pci0000:00/0000:00:1a.0/usb3"));
    }
private:
    /** The logic for testing whether a sysfs address corresponds to an
     * interface of a device.  Both must be referenced by their canonical
     * sysfs paths.  This is not tested, as the test requires file-system
     * interaction. */
    bool isAnInterfaceOf(const char *pcszIface, const char *pcszDev)
    {
        size_t cchDev = strlen(pcszDev);

        AssertPtr(pcszIface);
        AssertPtr(pcszDev);
        Assert(pcszIface[0] == '/');
        Assert(pcszDev[0] == '/');
        Assert(pcszDev[cchDev - 1] != '/');
        /* If this passes, pcszIface is at least cchDev long */
        if (strncmp(pcszIface, pcszDev, cchDev))
            return false;
        /* If this passes, pcszIface is longer than cchDev */
        if (pcszIface[cchDev] != '/')
            return false;
        /* In sysfs an interface is an immediate subdirectory of the device */
        if (strchr(pcszIface + cchDev + 1, '/'))
            return false;
        /* And it always has a colon in its name */
        if (!strchr(pcszIface + cchDev + 1, ':'))
            return false;
        /* And hopefully we have now elimitated everything else */
        return true;
    }

    virtual bool handle(const char *pcszNode)
    {
        if (!isAnInterfaceOf(pcszNode, mInfo->mSysfsPath.c_str()))
            return true;
        try
        {
            mInfo->mInterfaces.push_back(pcszNode);
        }
        catch(std::bad_alloc &e)
        {
            return false;
        }
        return true;
    }
};

/**
 * Helper function to query the sysfs subsystem for information about USB
 * devices attached to the system.
 * @returns iprt status code
 * @param   pList      where to add information about the drives detected
 * @param   pfSuccess  Did we find anything?
 *
 * @returns IPRT status code
 */
static int getUSBDeviceInfoFromSysfs(USBDeviceInfoList *pList,
                                     bool *pfSuccess)
{
    AssertPtrReturn(pList, VERR_INVALID_POINTER);
    AssertPtrNullReturn(pfSuccess, VERR_INVALID_POINTER); /* Valid or Null */
    LogFlowFunc (("pList=%p, pfSuccess=%p\n",
                  pList, pfSuccess));
    size_t cDevices = pList->size();
    matchUSBDevice devHandler(pList);
    int rc = getDeviceInfoFromSysfs("/sys/bus/usb/devices", &devHandler);
    do {
        if (RT_FAILURE(rc))
            break;
        for (USBDeviceInfoList::iterator pInfo = pList->begin();
             pInfo != pList->end(); ++pInfo)
        {
            matchUSBInterface ifaceHandler(&*pInfo);
            rc = getDeviceInfoFromSysfs("/sys/bus/usb/devices", &ifaceHandler);
            if (RT_FAILURE(rc))
                break;
        }
    } while(0);
    if (RT_FAILURE(rc))
        /* Clean up again */
        while (pList->size() > cDevices)
            pList->pop_back();
    if (pfSuccess)
        *pfSuccess = RT_SUCCESS(rc);
    LogFlow (("rc=%Rrc\n", rc));
    return rc;
}
#endif /* VBOX_USB_WITH_SYSFS */

#if defined VBOX_USB_WITH_SYSFS && defined VBOX_WITH_DBUS
/** Wrapper class around DBusError for automatic cleanup */
class autoDBusError
{
    DBusError mError;
public:
    autoDBusError () { dbus_error_init (&mError); }
    ~autoDBusError ()
    {
        if (IsSet())
            dbus_error_free (&mError);
    }
    DBusError &get () { return mError; }
    bool IsSet ()
    {
        Assert((mError.name == NULL) == (mError.message == NULL));
        return (mError.name != NULL);
    }
    bool HasName (const char *pcszName)
    {
        Assert((mError.name == NULL) == (mError.message == NULL));
        return (RTStrCmp (mError.name, pcszName) == 0);
    }
    void FlowLog ()
    {
        if (IsSet ())
            LogFlow(("DBus error %s: %s\n", mError.name, mError.message));
    }
};

/**
 * Helper function for setting up a connection to the DBus daemon and
 * registering with the hal service.
 *
 * @note If libdbus is being loaded at runtime then be sure to call
 *       VBoxDBusCheckPresence before calling this.
 * @returns iprt status code
 * @param   ppConnection  where to store the connection handle
 */
/* static */
int halInit (RTMemAutoPtr <DBusConnection, VBoxHalShutdown> *pConnection)
{
    AssertReturn(VALID_PTR (pConnection), VERR_INVALID_POINTER);
    LogFlowFunc (("pConnection=%p\n", pConnection));
    int rc = VINF_SUCCESS;
    bool halSuccess = true;
    autoDBusError dbusError;

    RTMemAutoPtr <DBusConnection, VBoxDBusConnectionUnref> dbusConnection;
    dbusConnection = dbus_bus_get (DBUS_BUS_SYSTEM, &dbusError.get());
    if (!dbusConnection)
        halSuccess = false;
    if (halSuccess)
    {
        dbus_connection_set_exit_on_disconnect (dbusConnection.get(), false);
        halSuccess = dbus_bus_name_has_owner (dbusConnection.get(),
                                              "org.freedesktop.Hal", &dbusError.get());
    }
    if (halSuccess)
    {
        dbus_bus_add_match (dbusConnection.get(),
                            "type='signal',"
                            "interface='org.freedesktop.Hal.Manager',"
                            "sender='org.freedesktop.Hal',"
                            "path='/org/freedesktop/Hal/Manager'",
                            &dbusError.get());
        halSuccess = !dbusError.IsSet();
    }
    if (dbusError.HasName (DBUS_ERROR_NO_MEMORY))
        rc = VERR_NO_MEMORY;
    if (halSuccess)
        *pConnection = dbusConnection.release();
    LogFlowFunc(("rc=%Rrc, (*pConnection).get()=%p\n", rc, (*pConnection).get()));
    dbusError.FlowLog();
    return rc;
}

/**
 * Helper function for setting up a private connection to the DBus daemon and
 * registering with the hal service.  Private connections are considered
 * unsociable and should not be used unnecessarily (as per the DBus API docs).
 *
 * @note If libdbus is being loaded at runtime then be sure to call
 *       VBoxDBusCheckPresence before calling this.
 * @returns iprt status code
 * @param   pConnection  where to store the connection handle
 */
/* static */
int halInitPrivate (RTMemAutoPtr <DBusConnection, VBoxHalShutdownPrivate> *pConnection)
{
    AssertReturn(VALID_PTR (pConnection), VERR_INVALID_POINTER);
    LogFlowFunc (("pConnection=%p\n", pConnection));
    int rc = VINF_SUCCESS;
    bool halSuccess = true;
    autoDBusError dbusError;

    RTMemAutoPtr <DBusConnection, VBoxDBusConnectionCloseAndUnref> dbusConnection;
    dbusConnection = dbus_bus_get_private (DBUS_BUS_SYSTEM, &dbusError.get());
    if (!dbusConnection)
        halSuccess = false;
    if (halSuccess)
    {
        dbus_connection_set_exit_on_disconnect (dbusConnection.get(), false);
        halSuccess = dbus_bus_name_has_owner (dbusConnection.get(),
                                              "org.freedesktop.Hal", &dbusError.get());
    }
    if (halSuccess)
    {
        dbus_bus_add_match (dbusConnection.get(),
                            "type='signal',"
                            "interface='org.freedesktop.Hal.Manager',"
                            "sender='org.freedesktop.Hal',"
                            "path='/org/freedesktop/Hal/Manager'",
                            &dbusError.get());
        halSuccess = !dbusError.IsSet();
    }
    if (dbusError.HasName (DBUS_ERROR_NO_MEMORY))
        rc = VERR_NO_MEMORY;
    if (halSuccess)
        *pConnection = dbusConnection.release();
    LogFlowFunc(("rc=%Rrc, (*pConnection).get()=%p\n", rc, (*pConnection).get()));
    dbusError.FlowLog();
    return rc;
}

/**
 * Helper function for shutting down a connection to DBus and hal.
 * @param   pConnection  the connection handle
 */
/* extern */
void VBoxHalShutdown (DBusConnection *pConnection)
{
    AssertReturnVoid(VALID_PTR (pConnection));
    LogFlowFunc (("pConnection=%p\n", pConnection));
    autoDBusError dbusError;

    dbus_bus_remove_match (pConnection,
                           "type='signal',"
                           "interface='org.freedesktop.Hal.Manager',"
                           "sender='org.freedesktop.Hal',"
                           "path='/org/freedesktop/Hal/Manager'",
                           &dbusError.get());
    dbus_connection_unref (pConnection);
    LogFlowFunc(("returning\n"));
    dbusError.FlowLog();
}

/**
 * Helper function for shutting down a private connection to DBus and hal.
 * @param   pConnection  the connection handle
 */
/* extern */
void VBoxHalShutdownPrivate (DBusConnection *pConnection)
{
    AssertReturnVoid(VALID_PTR (pConnection));
    LogFlowFunc (("pConnection=%p\n", pConnection));
    autoDBusError dbusError;

    dbus_bus_remove_match (pConnection,
                           "type='signal',"
                           "interface='org.freedesktop.Hal.Manager',"
                           "sender='org.freedesktop.Hal',"
                           "path='/org/freedesktop/Hal/Manager'",
                           &dbusError.get());
    dbus_connection_close (pConnection);
    dbus_connection_unref (pConnection);
    LogFlowFunc(("returning\n"));
    dbusError.FlowLog();
}

/** Wrapper around dbus_connection_unref.  We need this to use it as a real
 * function in auto pointers, as a function pointer won't wash here. */
/* extern */
void VBoxDBusConnectionUnref(DBusConnection *pConnection)
{
    dbus_connection_unref(pConnection);
}

/**
 * This function closes and unrefs a private connection to dbus.  It should
 * only be called once no-one else is referencing the connection.
 */
/* extern */
void VBoxDBusConnectionCloseAndUnref(DBusConnection *pConnection)
{
    dbus_connection_close(pConnection);
    dbus_connection_unref(pConnection);
}

/** Wrapper around dbus_message_unref.  We need this to use it as a real
 * function in auto pointers, as a function pointer won't wash here. */
/* extern */
void VBoxDBusMessageUnref(DBusMessage *pMessage)
{
    dbus_message_unref(pMessage);
}

/**
 * Find the UDIs of hal entries that contain Key=Value property.
 * @returns iprt status code.  If a non-fatal error occurs, we return success
 *          but reset pMessage to NULL.
 * @param   pConnection an initialised connection DBus
 * @param   pszKey      the property key
 * @param   pszValue    the property value
 * @param   pMessage    where to store the return DBus message.  This must be
 *                      parsed to get at the UDIs.  NOT optional.
 */
/* static */
int halFindDeviceStringMatch (DBusConnection *pConnection, const char *pszKey,
                              const char *pszValue,
                              RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> *pMessage)
{
    AssertReturn(   VALID_PTR (pConnection) && VALID_PTR (pszKey)
                 && VALID_PTR (pszValue) && VALID_PTR (pMessage),
                 VERR_INVALID_POINTER);
    LogFlowFunc (("pConnection=%p, pszKey=%s, pszValue=%s, pMessage=%p\n",
                  pConnection, pszKey, pszValue, pMessage));
    int rc = VINF_SUCCESS;  /* We set this to failure on fatal errors. */
    bool halSuccess = true;  /* We set this to false to abort the operation. */
    autoDBusError dbusError;

    RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> message, reply;
    if (halSuccess && RT_SUCCESS(rc))
    {
        message = dbus_message_new_method_call ("org.freedesktop.Hal",
                                                "/org/freedesktop/Hal/Manager",
                                                "org.freedesktop.Hal.Manager",
                                                "FindDeviceStringMatch");
        if (!message)
            rc = VERR_NO_MEMORY;
    }
    if (halSuccess && RT_SUCCESS(rc))
    {
        DBusMessageIter iterAppend;
        dbus_message_iter_init_append (message.get(), &iterAppend);
        dbus_message_iter_append_basic (&iterAppend, DBUS_TYPE_STRING, &pszKey);
        dbus_message_iter_append_basic (&iterAppend, DBUS_TYPE_STRING, &pszValue);
        reply = dbus_connection_send_with_reply_and_block (pConnection,
                                                            message.get(), -1,
                                                            &dbusError.get());
        if (!reply)
            halSuccess = false;
    }
    *pMessage = reply.release ();
    LogFlowFunc (("rc=%Rrc, *pMessage.value()=%p\n", rc, (*pMessage).get()));
    dbusError.FlowLog();
    return rc;
}

/**
 * Find the UDIs of hal entries that contain Key=Value property and return the
 * result on the end of a vector of iprt::MiniString.
 * @returns iprt status code.  If a non-fatal error occurs, we return success
 *          but set *pfSuccess to false.
 * @param   pConnection an initialised connection DBus
 * @param   pszKey      the property key
 * @param   pszValue    the property value
 * @param   pMatches    pointer to an array of iprt::MiniString to append the
 *                      results to.  NOT optional.
 * @param   pfSuccess   will be set to true if the operation succeeds
 */
/* static */
int halFindDeviceStringMatchVector (DBusConnection *pConnection,
                                    const char *pszKey, const char *pszValue,
                                    std::vector<iprt::MiniString> *pMatches,
                                    bool *pfSuccess)
{
    AssertPtrReturn (pConnection, VERR_INVALID_POINTER);
    AssertPtrReturn (pszKey, VERR_INVALID_POINTER);
    AssertPtrReturn (pszValue, VERR_INVALID_POINTER);
    AssertPtrReturn (pMatches, VERR_INVALID_POINTER);
    AssertReturn(pfSuccess == NULL || VALID_PTR (pfSuccess), VERR_INVALID_POINTER);
    LogFlowFunc (("pConnection=%p, pszKey=%s, pszValue=%s, pMatches=%p, pfSuccess=%p\n",
                  pConnection, pszKey, pszValue, pMatches, pfSuccess));
    int rc = VINF_SUCCESS;  /* We set this to failure on fatal errors. */
    bool halSuccess = true;  /* We set this to false to abort the operation. */

    RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> message, replyFind;
    DBusMessageIter iterFind, iterUdis;

    if (halSuccess && RT_SUCCESS(rc))
    {
        rc = halFindDeviceStringMatch (pConnection, pszKey, pszValue,
                                       &replyFind);
        if (!replyFind)
            halSuccess = false;
    }
    if (halSuccess && RT_SUCCESS(rc))
    {
        dbus_message_iter_init (replyFind.get(), &iterFind);
        if (dbus_message_iter_get_arg_type (&iterFind) != DBUS_TYPE_ARRAY)
            halSuccess = false;
    }
    if (halSuccess && RT_SUCCESS(rc))
        dbus_message_iter_recurse (&iterFind, &iterUdis);
    for (;    halSuccess && RT_SUCCESS(rc)
           && dbus_message_iter_get_arg_type (&iterUdis) == DBUS_TYPE_STRING;
         dbus_message_iter_next(&iterUdis))
    {
        /* Now get all UDIs from the iterator */
        const char *pszUdi;
        dbus_message_iter_get_basic (&iterUdis, &pszUdi);
        try
        {
            pMatches->push_back(pszUdi);
        }
        catch(std::bad_alloc &e)
        {
            rc = VERR_NO_MEMORY;
        }
    }
    if (pfSuccess != NULL)
        *pfSuccess = halSuccess;
    LogFlow (("rc=%Rrc, halSuccess=%d\n", rc, halSuccess));
    return rc;
}

/**
 * Read a set of string properties for a device.  If some of the properties are
 * not of type DBUS_TYPE_STRING or do not exist then a NULL pointer will be
 * returned for them.
 * @returns iprt status code.  If the operation failed for non-fatal reasons
 *          then we return success and leave pMessage untouched - reset it
 *          before the call to detect this.
 * @param   pConnection  an initialised connection DBus
 * @param   pszUdi       the Udi of the device
 * @param   cProps       the number of property values to look up
 * @param   papszKeys    the keys of the properties to be looked up
 * @param   papszValues  where to store the values of the properties.  The
 *                       strings returned will be valid until the message
 *                       returned in @a ppMessage is freed.  Undefined if
 *                       the message is NULL.
 * @param   pMessage     where to store the return DBus message.  The caller
 *                       is responsible for freeing this once they have
 *                       finished with the value strings.  NOT optional.
 */
/* static */
int halGetPropertyStrings (DBusConnection *pConnection, const char *pszUdi,
                           size_t cProps, const char **papszKeys,
                           char **papszValues,
                           RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> *pMessage)
{
    AssertReturn(   VALID_PTR (pConnection) && VALID_PTR (pszUdi)
                 && VALID_PTR (papszKeys) && VALID_PTR (papszValues)
                 && VALID_PTR (pMessage),
                 VERR_INVALID_POINTER);
    LogFlowFunc (("pConnection=%p, pszUdi=%s, cProps=%llu, papszKeys=%p, papszValues=%p, pMessage=%p\n",
                  pConnection, pszUdi, cProps, papszKeys, papszValues, pMessage));
    int rc = VINF_SUCCESS;  /* We set this to failure on fatal errors. */
    bool halSuccess = true;  /* We set this to false to abort the operation. */
    autoDBusError dbusError;

    RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> message, reply;
    DBusMessageIter iterGet, iterProps;

    /* Initialise the return array to NULLs */
    for (size_t i = 0; i < cProps; ++i)
        papszValues[i] = NULL;

    /* Send a GetAllProperties message to hald */
    message = dbus_message_new_method_call ("org.freedesktop.Hal", pszUdi,
                                            "org.freedesktop.Hal.Device",
                                            "GetAllProperties");
    if (!message)
        rc = VERR_NO_MEMORY;
    if (halSuccess && RT_SUCCESS(rc))
    {
        reply = dbus_connection_send_with_reply_and_block (pConnection,
                                                           message.get(), -1,
                                                           &dbusError.get());
        if (!reply)
            halSuccess = false;
    }

    /* Parse the reply */
    if (halSuccess && RT_SUCCESS(rc))
    {
        dbus_message_iter_init (reply.get(), &iterGet);
        if (   dbus_message_iter_get_arg_type (&iterGet) != DBUS_TYPE_ARRAY
            && dbus_message_iter_get_element_type (&iterGet) != DBUS_TYPE_DICT_ENTRY)
            halSuccess = false;
    }
    if (halSuccess && RT_SUCCESS(rc))
        dbus_message_iter_recurse (&iterGet, &iterProps);
    /* Go through all entries in the reply and see if any match our keys. */
    while (   halSuccess && RT_SUCCESS(rc)
           &&    dbus_message_iter_get_arg_type (&iterProps)
              == DBUS_TYPE_DICT_ENTRY)
    {
        const char *pszKey;
        DBusMessageIter iterEntry, iterValue;
        dbus_message_iter_recurse (&iterProps, &iterEntry);
        dbus_message_iter_get_basic (&iterEntry, &pszKey);
        dbus_message_iter_next (&iterEntry);
        dbus_message_iter_recurse (&iterEntry, &iterValue);
        /* Fill in any matches. */
        for (size_t i = 0; i < cProps; ++i)
            if (strcmp (pszKey, papszKeys[i]) == 0)
            {
                if (dbus_message_iter_get_arg_type (&iterValue) == DBUS_TYPE_STRING)
                    dbus_message_iter_get_basic (&iterValue, &papszValues[i]);
            }
        dbus_message_iter_next (&iterProps);
    }
    if (RT_SUCCESS(rc) && halSuccess)
        *pMessage = reply.release();
    if (dbusError.HasName (DBUS_ERROR_NO_MEMORY))
        rc = VERR_NO_MEMORY;
    LogFlowFunc (("rc=%Rrc, *pMessage.value()=%p\n", rc, (*pMessage).get()));
    dbusError.FlowLog();
    return rc;
}

/**
 * Read a set of string properties for a device.  If some properties do not
 * exist or are not of type DBUS_TYPE_STRING, we will still fetch the others.
 * @returns iprt status code.  If the operation failed for non-fatal reasons
 *          then we return success and set *pfSuccess to false.
 * @param   pConnection  an initialised connection DBus
 * @param   pszUdi       the Udi of the device
 * @param   cProps       the number of property values to look up
 * @param   papszKeys    the keys of the properties to be looked up
 * @param   pMatches     pointer to an empty array of iprt::MiniString to append the
 *                       results to.  NOT optional.
 * @param   pfMatches    pointer to an array of boolean values indicating
 *                       whether the respective property is a string.  If this
 *                       is not supplied then all properties must be strings
 *                       for the operation to be considered successful
 * @param   pfSuccess    will be set to true if the operation succeeds
 */
/* static */
int halGetPropertyStringsVector (DBusConnection *pConnection,
                                 const char *pszUdi, size_t cProps,
                                 const char **papszKeys,
                                 std::vector<iprt::MiniString> *pMatches,
                                 bool *pfMatches, bool *pfSuccess)
{
    AssertPtrReturn (pConnection, VERR_INVALID_POINTER);
    AssertPtrReturn (pszUdi, VERR_INVALID_POINTER);
    AssertPtrReturn (papszKeys, VERR_INVALID_POINTER);
    AssertPtrReturn (pMatches, VERR_INVALID_POINTER);
    AssertReturn((pfMatches == NULL) || VALID_PTR (pfMatches), VERR_INVALID_POINTER);
    AssertReturn((pfSuccess == NULL) || VALID_PTR (pfSuccess), VERR_INVALID_POINTER);
    AssertReturn(pMatches->empty(), VERR_INVALID_PARAMETER);
    LogFlowFunc (("pConnection=%p, pszUdi=%s, cProps=%llu, papszKeys=%p, pMatches=%p, pfMatches=%p, pfSuccess=%p\n",
                  pConnection, pszUdi, cProps, papszKeys, pMatches, pfMatches, pfSuccess));
    RTMemAutoPtr <char *> values(cProps);
    RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> message;
    bool halSuccess = true;
    int rc = halGetPropertyStrings (pConnection, pszUdi, cProps, papszKeys,
                                    values.get(), &message);
    if (!message)
        halSuccess = false;
    for (size_t i = 0; RT_SUCCESS(rc) && halSuccess && i < cProps; ++i)
    {
        bool fMatches = values[i] != NULL;
        if (pfMatches != NULL)
            pfMatches[i] = fMatches;
        else
            halSuccess = fMatches;
        try
        {
            pMatches->push_back(fMatches ? values[i] : "");
        }
        catch(std::bad_alloc &e)
        {
            rc = VERR_NO_MEMORY;
        }
    }
    if (pfSuccess != NULL)
        *pfSuccess = halSuccess;
    if (RT_SUCCESS(rc) && halSuccess)
    {
        Assert(pMatches->size() == cProps);
        AssertForEach(j, size_t, 0, cProps,    (pfMatches == NULL)
                                            || (pfMatches[j] == true)
                                            || ((pfMatches[j] == false) && (pMatches[j].size() == 0)));
    }
    LogFlowFunc (("rc=%Rrc, halSuccess=%d\n", rc, halSuccess));
    return rc;
}


/**
 * Helper function to query the hal subsystem for information about USB devices
 * attached to the system.
 * @returns iprt status code
 * @param   pList      where to add information about the devices detected
 * @param   pfSuccess  will be set to true if all interactions with hal
 *                     succeeded and to false otherwise.  Optional.
 *
 * @returns IPRT status code
 */
/* static */
int getUSBDeviceInfoFromHal(USBDeviceInfoList *pList, bool *pfSuccess)
{
    AssertReturn(VALID_PTR (pList) && (pfSuccess == NULL || VALID_PTR (pfSuccess)),
                 VERR_INVALID_POINTER);
    LogFlowFunc (("pList=%p, pfSuccess=%p\n", pList, pfSuccess));
    int rc = VINF_SUCCESS;  /* We set this to failure on fatal errors. */
    bool halSuccess = true;  /* We set this to false to abort the operation. */
    autoDBusError dbusError;

    RTMemAutoPtr<DBusMessage, VBoxDBusMessageUnref> message, replyFind, replyGet;
    RTMemAutoPtr<DBusConnection, VBoxHalShutdown> dbusConnection;
    DBusMessageIter iterFind, iterUdis;

    /* Connect to hal */
    rc = halInit (&dbusConnection);
    if (!dbusConnection)
        halSuccess = false;
    /* Get an array of all devices in the usb_device subsystem */
    if (halSuccess && RT_SUCCESS(rc))
    {
        rc = halFindDeviceStringMatch(dbusConnection.get(), "info.subsystem",
                                      "usb_device", &replyFind);
        if (!replyFind)
            halSuccess = false;
    }
    if (halSuccess && RT_SUCCESS(rc))
    {
        dbus_message_iter_init(replyFind.get(), &iterFind);
        if (dbus_message_iter_get_arg_type (&iterFind) != DBUS_TYPE_ARRAY)
            halSuccess = false;
    }
    /* Recurse down into the array and query interesting information about the
     * entries. */
    if (halSuccess && RT_SUCCESS(rc))
        dbus_message_iter_recurse(&iterFind, &iterUdis);
    for (;    halSuccess && RT_SUCCESS(rc)
           && dbus_message_iter_get_arg_type(&iterUdis) == DBUS_TYPE_STRING;
         dbus_message_iter_next(&iterUdis))
    {
        /* Get the device node and the sysfs path for the current entry. */
        const char *pszUdi;
        dbus_message_iter_get_basic (&iterUdis, &pszUdi);
        static const char *papszKeys[] = { "linux.device_file", "linux.sysfs_path" };
        char *papszValues[RT_ELEMENTS(papszKeys)];
        rc = halGetPropertyStrings(dbusConnection.get(), pszUdi, RT_ELEMENTS(papszKeys),
                                   papszKeys, papszValues, &replyGet);
        const char *pszDevice = papszValues[0], *pszSysfsPath = papszValues[1];
        /* Get the interfaces. */
        if (!!replyGet && pszDevice && pszSysfsPath)
        {
            USBDeviceInfo info(pszDevice, pszSysfsPath);
            bool ifaceSuccess = true;  /* If we can't get the interfaces, just
                                        * skip this one device. */
            rc = getUSBInterfacesFromHal(&info.mInterfaces, pszUdi, &ifaceSuccess);
            if (RT_SUCCESS(rc) && halSuccess && ifaceSuccess)
                try
                {
                    pList->push_back(info);
                }
                catch(std::bad_alloc &e)
                {
                    rc = VERR_NO_MEMORY;
                }
        }
    }
    if (dbusError.HasName (DBUS_ERROR_NO_MEMORY))
        rc = VERR_NO_MEMORY;
    if (pfSuccess != NULL)
        *pfSuccess = halSuccess;
    LogFlow(("rc=%Rrc, halSuccess=%d\n", rc, halSuccess));
    dbusError.FlowLog();
    return rc;
}

/**
 * Helper function to query the hal subsystem for information about USB devices
 * attached to the system, using the older API.
 * @returns iprt status code
 * @param   pList      where to add information about the devices detected
 * @param   pfSuccess  will be set to true if all interactions with hal
 *                     succeeded and to false otherwise.  Optional.
 *
 * @returns IPRT status code
 */
/* static */
int getOldUSBDeviceInfoFromHal(USBDeviceInfoList *pList, bool *pfSuccess)
{
    AssertReturn(VALID_PTR (pList) && (pfSuccess == NULL || VALID_PTR (pfSuccess)),
                 VERR_INVALID_POINTER);
    LogFlowFunc (("pList=%p, pfSuccess=%p\n", pList, pfSuccess));
    int rc = VINF_SUCCESS;  /* We set this to failure on fatal errors. */
    bool halSuccess = true;  /* We set this to false to abort the operation. */
    autoDBusError dbusError;

    RTMemAutoPtr<DBusMessage, VBoxDBusMessageUnref> message, replyFind, replyGet;
    RTMemAutoPtr<DBusConnection, VBoxHalShutdown> dbusConnection;
    DBusMessageIter iterFind, iterUdis;

    /* Connect to hal */
    rc = halInit(&dbusConnection);
    if (!dbusConnection)
        halSuccess = false;
    /* Get an array of all devices in the usb_device subsystem */
    if (halSuccess && RT_SUCCESS(rc))
    {
        rc = halFindDeviceStringMatch(dbusConnection.get(), "info.category",
                                       "usbraw", &replyFind);
        if (!replyFind)
            halSuccess = false;
    }
    if (halSuccess && RT_SUCCESS(rc))
    {
        dbus_message_iter_init(replyFind.get(), &iterFind);
        if (dbus_message_iter_get_arg_type(&iterFind) != DBUS_TYPE_ARRAY)
            halSuccess = false;
    }
    /* Recurse down into the array and query interesting information about the
     * entries. */
    if (halSuccess && RT_SUCCESS(rc))
        dbus_message_iter_recurse(&iterFind, &iterUdis);
    for (;    halSuccess && RT_SUCCESS(rc)
           && dbus_message_iter_get_arg_type(&iterUdis) == DBUS_TYPE_STRING;
         dbus_message_iter_next(&iterUdis))
    {
        /* Get the device node and the sysfs path for the current entry. */
        const char *pszUdi;
        dbus_message_iter_get_basic(&iterUdis, &pszUdi);
        static const char *papszKeys[] = { "linux.device_file", "info.parent" };
        char *papszValues[RT_ELEMENTS(papszKeys)];
        rc = halGetPropertyStrings(dbusConnection.get(), pszUdi, RT_ELEMENTS(papszKeys),
                                   papszKeys, papszValues, &replyGet);
        const char *pszDevice = papszValues[0], *pszSysfsPath = papszValues[1];
        /* Get the interfaces. */
        if (!!replyGet && pszDevice && pszSysfsPath)
        {
            USBDeviceInfo info(pszDevice, pszSysfsPath);
            bool ifaceSuccess = false;  /* If we can't get the interfaces, just
                                         * skip this one device. */
            rc = getUSBInterfacesFromHal(&info.mInterfaces, pszSysfsPath,
                                         &ifaceSuccess);
            if (RT_SUCCESS(rc) && halSuccess && ifaceSuccess)
                try
                {
                    pList->push_back(info);
                }
                catch(std::bad_alloc &e)
                {
                    rc = VERR_NO_MEMORY;
                }
        }
    }
    if (dbusError.HasName(DBUS_ERROR_NO_MEMORY))
        rc = VERR_NO_MEMORY;
    if (pfSuccess != NULL)
        *pfSuccess = halSuccess;
    LogFlow(("rc=%Rrc, halSuccess=%d\n", rc, halSuccess));
    dbusError.FlowLog();
    return rc;
}


/**
 * Helper function to query the hal subsystem for information about USB devices
 * attached to the system.
 * @returns iprt status code
 * @param   pList      where to add information about the devices detected.  If
 *                     certain interfaces are not found (@a pfFound is false on
 *                     return) this may contain invalid information.
 * @param   pcszUdi    the hal UDI of the device
 * @param   pfSuccess  will be set to true if the operation succeeds and to
 *                     false if it fails for non-critical reasons.  Optional.
 *
 * @returns IPRT status code
 */
/* static */
int getUSBInterfacesFromHal(std::vector<iprt::MiniString> *pList,
                            const char *pcszUdi, bool *pfSuccess)
{
    AssertReturn(VALID_PTR(pList) && VALID_PTR(pcszUdi) &&
                 (pfSuccess == NULL || VALID_PTR (pfSuccess)),
                 VERR_INVALID_POINTER);
    LogFlowFunc(("pList=%p, pcszUdi=%s, pfSuccess=%p\n", pList, pcszUdi,
                 pfSuccess));
    int rc = VINF_SUCCESS;  /* We set this to failure on fatal errors. */
    bool halSuccess = true;  /* We set this to false to abort the operation. */
    autoDBusError dbusError;

    RTMemAutoPtr <DBusMessage, VBoxDBusMessageUnref> message, replyFind, replyGet;
    RTMemAutoPtr <DBusConnection, VBoxHalShutdown> dbusConnection;
    DBusMessageIter iterFind, iterUdis;

    rc = halInit(&dbusConnection);
    if (!dbusConnection)
        halSuccess = false;
    if (halSuccess && RT_SUCCESS(rc))
    {
        /* Look for children of the current UDI. */
        rc = halFindDeviceStringMatch(dbusConnection.get(), "info.parent",
                                      pcszUdi, &replyFind);
        if (!replyFind)
            halSuccess = false;
    }
    if (halSuccess && RT_SUCCESS(rc))
    {
        dbus_message_iter_init(replyFind.get(), &iterFind);
        if (dbus_message_iter_get_arg_type(&iterFind) != DBUS_TYPE_ARRAY)
            halSuccess = false;
    }
    if (halSuccess && RT_SUCCESS(rc))
        dbus_message_iter_recurse(&iterFind, &iterUdis);
    for (;    halSuccess && RT_SUCCESS(rc)
           && dbus_message_iter_get_arg_type(&iterUdis) == DBUS_TYPE_STRING;
         dbus_message_iter_next(&iterUdis))
    {
        /* Now get the sysfs path and the subsystem from the iterator */
        const char *pszUdi;
        dbus_message_iter_get_basic(&iterUdis, &pszUdi);
        static const char *papszKeys[] = { "linux.sysfs_path", "info.subsystem",
                                           "linux.subsystem" };
        char *papszValues[RT_ELEMENTS(papszKeys)];
        rc = halGetPropertyStrings(dbusConnection.get(), pszUdi, RT_ELEMENTS(papszKeys),
                                   papszKeys, papszValues, &replyGet);
        const char *pszSysfsPath = papszValues[0], *pszInfoSubsystem = papszValues[1],
                   *pszLinuxSubsystem = papszValues[2];
        if (!replyGet)
            halSuccess = false;
        if (!!replyGet && pszSysfsPath == NULL)
            halSuccess = false;
        if (   halSuccess && RT_SUCCESS(rc)
            && RTStrCmp (pszInfoSubsystem, "usb_device") != 0  /* Children of buses can also be devices. */
            && RTStrCmp (pszLinuxSubsystem, "usb_device") != 0)
            try
            {
                pList->push_back(pszSysfsPath);
            }
            catch(std::bad_alloc &e)
            {
               rc = VERR_NO_MEMORY;
            }
    }
    if (dbusError.HasName(DBUS_ERROR_NO_MEMORY))
        rc = VERR_NO_MEMORY;
    if (pfSuccess != NULL)
        *pfSuccess = halSuccess;
    LogFlow(("rc=%Rrc, halSuccess=%d\n", rc, halSuccess));
    dbusError.FlowLog();
    return rc;
}

/**
 * When it is registered with DBus, this function will be called by
 * dbus_connection_read_write_dispatch each time a message is received over the
 * DBus connection.  We check whether that message was caused by a hal device
 * hotplug event, and if so we set a flag.  dbus_connection_read_write_dispatch
 * will return after calling its filter functions, and its caller should then
 * check the status of the flag passed to the filter function.
 *
 * @param   pConnection The DBus connection we are using.
 * @param   pMessage    The DBus message which just arrived.
 * @param   pvUser      A pointer to the flag variable we are to set.
 */
/* static */
DBusHandlerResult dbusFilterFunction(DBusConnection * /* pConnection */,
                                     DBusMessage *pMessage, void *pvUser)
{
    volatile bool *pTriggered = reinterpret_cast<volatile bool *>(pvUser);
    if (   dbus_message_is_signal(pMessage, "org.freedesktop.Hal.Manager",
                                  "DeviceAdded")
        || dbus_message_is_signal(pMessage, "org.freedesktop.Hal.Manager",
                                  "DeviceRemoved"))
    {
        *pTriggered = true;
    }
    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}
#endif  /* VBOX_USB_WITH_SYSFS && VBOX_WITH_DBUS */