Source file: /~heha/hs/usbview.zip/src/devnode.c

/*++

Copyright (c) 1998-1998 Microsoft Corporation

Module Name:

    DEVNODE.C

--*/

//*****************************************************************************
// I N C L U D E S
//*****************************************************************************

#include <windows.h>
#include <basetyps.h>
#include <cfgmgr32.h>

//#include <string.h>

//*****************************************************************************
// G L O B A L S
//*****************************************************************************

TCHAR buf[512];  // XXXXX How big does this have to be? Dynamically size it?

//*****************************************************************************
//
// DriverNameToDeviceDesc()
//
// Returns the Device Description of the DevNode with the matching DriverName.
// Returns NULL if the matching DevNode is not found.
//
// The caller should copy the returned string buffer instead of just saving
// the pointer value.  XXXXX Dynamically allocate return buffer?
//
//*****************************************************************************

PTSTR DriverNameToDeviceDesc(PTSTR DriverName) {
 DEVINST     devInst;
 DEVINST     devInstNext;
 CONFIGRET   cr;
 ULONG       walkDone = 0;
 ULONG       len;

    // Get Root DevNode
    //
 cr = CM_Locate_DevNode(&devInst,NULL,0);

 if (cr != CR_SUCCESS) return NULL;

    // Do a depth first search for the DevNode with a matching
    // DriverName value
    //
 while (!walkDone) {
        // Get the DriverName value
        //
  len = sizeof(buf);
  cr = CM_Get_DevNode_Registry_Property(devInst,CM_DRP_DRIVER,NULL,buf,&len,0);

        // If the DriverName value matches, return the DeviceDescription
        //
  if (cr == CR_SUCCESS && lstrcmpi(DriverName, buf) == 0) {
   len = sizeof(buf);
   cr = CM_Get_DevNode_Registry_Property(devInst,CM_DRP_DEVICEDESC,NULL,buf,&len,0);

   if (cr == CR_SUCCESS) return buf;
   else return NULL;
  }

        // This DevNode didn't match, go down a level to the first child.
        //
  cr = CM_Get_Child(&devInstNext,devInst,0);

  if (cr == CR_SUCCESS) {
   devInst = devInstNext;
   continue;
  }

        // Can't go down any further, go across to the next sibling.  If
        // there are no more siblings, go back up until there is a sibling.
        // If we can't go up any further, we're back at the root and we're
        // done.
        //
  for (;;) {
   cr = CM_Get_Sibling(&devInstNext,devInst,0);
   if (cr == CR_SUCCESS) {
    devInst = devInstNext;
    break;
   }
   cr = CM_Get_Parent(&devInstNext,devInst,0);
   if (cr == CR_SUCCESS) devInst = devInstNext;
   else{
    walkDone = 1;
    break;
   }
  }
 }
 return NULL;
}