I use the following code to verify that a serial port name is valid on the computer:
typedef std::pair<StrAsc const, bool> port_pair_type;
typedef std::list<port_pair_type> port_pairs_type;
port_pairs_type pairs;
StrBin config_buffer;
config_buffer.fill(0,sizeof(COMMCONFIG));
while(!pairs.empty())
{
port_pair_type pair(pairs.front());
pairs.pop_front();
if(!pair.second)
{
// we need to get the default configuration for the port. This may
// require some fudging on the buffer size. That is why two calls
// are being made.
uint4 config_size = config_buffer.length();
StrUni temp(pair.first);
COMMCONFIG *config(reinterpret_cast<COMMCONFIG *>(config_buffer.getContents_writable()));
config->dwSize = sizeof(COMMCONFIG);
rcd = GetDefaultCommConfigW(
temp.c_str(), config, &config_size);
if(!rcd && config_buffer.length() < config_size)
{
config_buffer.fill(0, config_size);
config = reinterpret_cast<COMMCONFIG *>(config_buffer.getContents_writable());
config->dwSize = sizeof(COMMCONFIG);
rcd = GetDefaultCommConfigW(
temp.c_str(),
reinterpret_cast<COMMCONFIG *>(config_buffer.getContents_writable()),
&config_size);
}
// if the call succeeded, we can go ahead and look at the
// configuration structure.
if(rcd)
{
COMMCONFIG const *config = reinterpret_cast<COMMCONFIG const *>(
config_buffer.getContents());
if(config->dwProviderSubType == PST_RS232)
port_names.push_back(pair.first);
}
else
{
OsException error("GetDefaultCommConfig Failed");
trace("\"%s\"", error.what());
}
}
else
port_names.push_back(pair.first);
}
On windows 10, when trying to confirm a serial port that uses usbser.sys, the call to GetDefaultCommConfig() is failing and the error code returned by GetLastError() is 87 (invalid parameter). As I am aware, the usbser.sys driver has been rewritten on windows 10 and I suspect that this is a problem with that driver. Does anyone else have an idea of what might be going wrong?
This had been a bug in usbser.sys and was fixed with the Windows 10 Update KB3124262 from 27.01.2016.
The Microsoft employee explained:
The COM port name in the HKLM\HARDWARE\DEVICEMAP\SERIALCOMM registry is not NULL terminated.
Related discussion on MSDN
Because of Windows 10's update policies this issue should not appear in the future anymore.
When you call GetDefaultCommConfigW the second time you probably need to config->dwSize to the new size the structure. Eg:
config->dwSize = config_size;
Related
Our program has a piece of code that calculates the list of computers on our local network. It uses the Windows Networking API (WNetOpenEnum/WNetEnumResource) to unwind the network. For many years, the resulting list was identical to the one that can be seen in Windows Explorer under the "Network" entry. However, recently we have noticed that the same code returns an empty list. During debugging I found that WNetOpenEnum returns error 1231 (ERROR_NETWORK_UNREACHABLE) when it is called for the "Microsoft Windows Network" under the root node.
I have to mention, though I'm pretty sure it has nothing to do with the matter, that the network unwinding is done multithreaded, to avoid possible delays in the main GUI thread. Each time a node of type RESOURCEUSAGE_CONTAINER is encountered, a new worker thread is launched. The thread function calls the following procedure:
DWORD WINAPI EnumNetwork(NETRESOURCE_M* lpNR)
{
const int BUF_SIZE = 16384; // 16K is a good size.
HANDLE hEnum;
DWORD Result;
// Call the WNetOpenEnum function to begin the enumeration.
Result = ::WNetOpenEnum(RESOURCE_GLOBALNET, // all network
RESOURCETYPE_ANY, // all resource types
0, // enumerate all
(LPNETRESOURCE)lpNR,// parent resource
&hEnum); // enumeration handle
if (Result != NO_ERROR) // -> for "Microsoft Windows Network" Result = 1231
return Result;
std::vector<std::wstring> SrvList;
// Allocate buffer for enumeration.
LPNETRESOURCE lpEnumNR = (LPNETRESOURCE)new char[BUF_SIZE];
if (lpEnumNR == 0)
Result = ERROR_OUTOFMEMORY;
else
{
while (1)
{
::ZeroMemory(lpEnumNR, BUF_SIZE); // Initialize the buffer.
DWORD NumEntries = -1; // Enumerate all entries.
DWORD BufSize = BUF_SIZE;
// Call WNetEnumResource to continue the enumeration.
Result = ::WNetEnumResource(hEnum, // enumeration handle
&NumEntries,// number of entries to enumerate
lpEnumNR, // array of resources to return
&BufSize); // buffer size
if (Result == NO_ERROR)
{
// If the call succeeds, loop through the array.
for (unsigned i = 0; i < NumEntries; ++i)
{
if (lpEnumNR[i].dwDisplayType == RESOURCEDISPLAYTYPE_SERVER)
{
// Collect servers.
LPCWSTR SrvName = lpEnumNR[i].lpRemoteName;
if (PathHelpers::IsFullPath(SrvName))
SrvList.push_back(SrvName);
}
else if ((lpEnumNR[i].dwUsage & RESOURCEUSAGE_CONTAINER) &&
lpEnumNR[i].lpRemoteName != 0)
{
TCHAR PathBuf[1024] = {0};
if (lpNR && lpNR->Path)
{
_tcscpy(PathBuf, lpNR->Path);
::PathAddBackslash(PathBuf);
}
_tcscat(PathBuf, lpEnumNR[i].lpRemoteName);
if (RegisterServer(PathBuf))
{
// Start new thread for recursive enumeration.
NETRESOURCE_M* lpChildNR = DeepCopyNR(&lpEnumNR[i], PathBuf);
ExploreNetwork(lpChildNR); // -> this starts a worker thread
}
else
{
GetLogger().LogMessage(
_T("Cycles found while unwinding network: %s"), PathBuf);
}
}
}
}
else
{
if (Result == ERROR_NO_MORE_ITEMS)
Result = NO_ERROR;
break;
}
} // end while
delete [] (char*)lpEnumNR;
} // end if
::WNetCloseEnum(hEnum);
if (!SrvList.empty())
NotifyServerAdded(SrvList);
return Result;
}
where NETRESOURCE_M is the structure
struct NETRESOURCE_M
{
NETRESOURCE NR;
LPTSTR Path;
};
Trying to figure out what could have caused such a sudden change in behavior, I found in Google that a few years ago Microsoft disabled the SMB1 protocol, which could affect Network Discovery. However, I can't believe they could have damaged their own API without saying a word in the documentation.
EDIT: At the same time, Windows Explorer has a bunch of computers under its "Network" node. In the network settings, the network type is "Domain", and the network discovery is ON. Services "Function Discovery Provider Host" and "Function Discovery Resources Publication" are running. Windows OS build is 19042.685.
Edit 2: The Sysinternals' "ShareEnum" tool also fails with the error: "No domains or workgroups where found on your network". Because of this, and also because some time ago our company moved all of its computers to a different network, I got the feeling that the problem is in the network configuration. Such as though the network is declared as "Domain", the computers were not enrolled to this domain. I do not understand much in that, but something like this.
I am trying to get the version of a file. I want to look at the version number of this file to determine which OS is installed on a non-booted drive (I'll actually be doing this from a Win PE environment and trying to determine if the main drive has Windows XP or Windows 7 installed). Anyway, I have the following
wchar_t *fileName;
fileName = new wchar_t[255];
lstrcpy(fileName, hdds[HardDriveIndexes::SystemDrive].driveLetter.c_str());
lstrcat(fileName, L"Windows\\System32\\winload.exe");
TCHAR *versionInfoBuffer;
DWORD versionDataSize;
if (versionDataSize = GetFileVersionInfoSize(fileName, NULL) != 0)
{
versionInfoBuffer = new TCHAR[versionDataSize];
BOOL versionInfoResult = FALSE;
versionInfoResult = GetFileVersionInfo(fileName, NULL, versionDataSize, versionInfoBuffer);
if (versionInfoResult == FALSE)
{
wprintf(L"The last error associated with getting version info is: %d\n", GetLastError());
}
}
else
{
wprintf(L"The last error associated with gettting version info size is: %d\n", GetLastError());
}
The problem is that GetFileVersionInfoSize() succeeds but always returns 1 as the size. This causes GetFileVersionInfo() to fail with error 122. So far I have only tested this on a Windows 7 system. There is another function GetFileVersionInfoSizeEx() that works as expected, but it is only supported from Vista onwards. I would like to keep XP support if possible (some of our old Win PE images are still based on XP).
Is GetFileVersionInfoSize() deprecated and I somehow can't find that information, am I using it incorrectly, etc.?
The problem isn't with the call, it's with your assignment; you need parens around it:
if ( ( versionDataSize = GetFileVersionInfoSize(fileName, NULL) ) != 0)
What you had written assigns the value of the expression size != 0, which is 1 for true.
I am trying to open a com port for reading and writing using C++ but I can't seem to pass the first stage of actually opening it. I get an INVALID_HANDLE_VALUE on the handle
with GetLastError FILE_NOT_FOUND. I have searched around the web for a couple of days I'm fresh out of ideas. I have searched through all the questions regarding COM on this website too.
I have scanned through the existing ports (or so I believe) to get the name of the port right.
I also tried combinations of _T("COM1") with the slashes, without the slashes, with colon, without colon and without the _T
I'm using windows 7 on 64 bit machine.
this is the code i got
I'll be glad for any input on this
void SendToCom(char* data, int len)
{
DWORD cbNeeded = 0;
DWORD dwPorts = 0;
EnumPorts(NULL, 1, NULL, 0, &cbNeeded, &dwPorts);
//What will be the return value
BOOL bSuccess = FALSE;
LPCSTR COM1 ;
BYTE* pPorts = static_cast<BYTE*>(malloc(cbNeeded));
bSuccess = EnumPorts(NULL, 1, pPorts, cbNeeded, &cbNeeded, &dwPorts);
if (bSuccess){
PORT_INFO_1* pPortInfo = reinterpret_cast<PORT_INFO_1*>(pPorts);
for (DWORD i=0; i<dwPorts; i++)
{
//If it looks like "COMX" then
size_t nLen = _tcslen(pPortInfo->pName);
if (nLen > 3)
{
if ((_tcsnicmp(pPortInfo->pName, _T("COM"), 3) == 0) ){
COM1 =pPortInfo->pName;
//COM1 ="\\\\.\\COM1";
HANDLE m_hCommPort = CreateFile( COM1 ,
GENERIC_READ|GENERIC_WRITE, // access ( read and write)
0, // (share) 0:cannot share the COM port
NULL, // security (None)
OPEN_EXISTING, // creation : open_existing
FILE_FLAG_OVERLAPPED, // we want overlapped operation
NULL // no templates file for COM port...
);
if (m_hCommPort==INVALID_HANDLE_VALUE)
{
DWORD err = GetLastError();
if (err == ERROR_FILE_NOT_FOUND) {
MessageBox(hWnd,"ERROR_FILE_NOT_FOUND",NULL,MB_ABORTRETRYIGNORE);
}
else
if(err == ERROR_INVALID_NAME) {
MessageBox(hWnd,"ERROR_INVALID_NAME",NULL,MB_ABORTRETRYIGNORE);
}
else
{
MessageBox(hWnd,"unkown error",NULL,MB_ABORTRETRYIGNORE);
}
}
else{
WriteAndReadPort(m_hCommPort,data);
}
}
pPortInfo++;
}
}
}
}
The Solution is to use
The Problem is, if your port is Bigger then 9 then you have to use the Syntax
LPCWSTR szPortName = L"\\\\.\\COM11";.
If you are on Windows 10 - running all system updates might help !
I had the same issue that opening port "COM4" returned an error ERROR_FILE_NOT_FOUND. When running the program as "Administrator" it worked. Now after a updating to 1511 the program can open "COM4" even not running as "Administrator".
http://www.cplusplus.com/forum/windows/163855/
Use CreateFileA(...) instead of CreateFile(...)
ERROR_FILE_NOT_FOUND can be produced from CreateFile(L"\\\\.\\COM1", ...) and CreateFile(L"COM1:", ...) after using the Device Manager to change the assigned COM Port number. Disabling and re-enabling the device, or unplugging and reconnecting the USB adapter resolves the issue.
A useful test to confirm whether it is your program or the system is to send data to the port in command prompt. A successful test will show an empty line. A failed test will show an error message.
C:\drop>echo > \\.\COM1
The system cannot find the file specified.
C:\drop>echo > \\.\COM1
C:\drop>
I wrote some code to connect with some share on a remote server. If WNetAddConnection2 returns ERROR_SESSION_CREDENTIAL_CONFLICT (1219), I will first cancel the connection by WNetCancelConnection2 (return NO_ERROR). And then reconnect. But WNetAddConnection2 still returns 1219.
Why this and how to fix it?
Here's my code
BOOL ADDirectorySearch::IPCConnect(CString strServerName, CString strDomainName, CString strUserName, CString strPassWord)
{
CString strServerNameWithSlash = _T("\\\\") + strServerName; //actually is \\klbnt
CString strFullUserName = strDomainName + _T("\\") + strUserName; //is domaintest\administrator
_bstr_t bstrServerNameWithSlash = strServerNameWithSlash;
_bstr_t bstrFullUserName = strFullUserName;
_bstr_t bstrPassWord = strPassWord;
DWORD dwResult;
NETRESOURCEW netResource;
memset(&netResource, 0, sizeof(netResource));
netResource.dwScope = RESOURCE_GLOBALNET;
netResource.dwType = RESOURCETYPE_DISK;
netResource.dwDisplayType = RESOURCEDISPLAYTYPE_GENERIC;
netResource.dwUsage = RESOURCEUSAGE_CONNECTABLE;
netResource.lpProvider = L"";
netResource.lpRemoteName = bstrServerNameWithSlash;//Remote IP like:\\192.168.1.11
dwResult = WNetAddConnection2W(&netResource, bstrPassWord, bstrFullUserName, CONNECT_INTERACTIVE);
if (dwResult == ERROR_SESSION_CREDENTIAL_CONFLICT)
{
dwResult = WNetCancelConnection2W(bstrServerNameWithSlash, CONNECT_UPDATE_PROFILE, TRUE);
if (dwResult == NO_ERROR)
{
dwResult = WNetAddConnection2W(&netResource, bstrPassWord, bstrFullUserName, CONNECT_INTERACTIVE);
}
else
{
//MyMessageBox_Error(_T("IPCConnect Error."), _T("Error"));
return FALSE;
}
}
if (dwResult == NO_ERROR)
{
return TRUE;
}
else
{
//MyMessageBox_Error(_T("IPCConnect Error."), _T("Error"));
return FALSE;
}
}
FYI: After typing "net use" in cmd, I got this, I feel there's something with error:
Status Local Remote Network
-------------------------------------------------------------------------------
OK \\klbnt\NRDC1001 Microsoft Windows Network
The command completed successfully.
I was just having this problem now, and basically it seemed that it was due to another process still having file open, even though I specified "true" as the last parameter of WNetCancelConnection2() to force close the connection. Once I shut-down that other process, I was able to use successfully switch between credentials connecting and re-connecting to the same share. This is on Windows 2012 (64-bit), and the share was local (referenced by the machinename).
BUT...it's still a problem if you want to connect to different shares on the same machine. If I try to connect to \\mymachine\share1 as user1 then to \\mymachine\share2 as user2, I get the 1219 error (even if it's in a completely different process). I have to explicitly call WNetCancelConnnection on \\mymachine\share1 before I can connect to share2, which means at the point you connect to a share on a particular machine, you may have to first enumerate existing connections and close each one.
Rather frustrating, and I can't understand the design principle here. It seems the flags to create temporary connections etc. have no effect on this behaviour either. Really what I want to be able to do is say "for this thread, connect to this share on this machine and as this user, such that all attempts to access files on the share are done with that user's credentials". That way what other processes/threads are doing can't cause issues with the current one.
In my code I try to get the permissions for a file with _stat(). Currently I want to run it under Windows. The method is as follows:
bool CFile::Private::checkPermissions(std::string sFilename, CFile::EOpenmode iOpenmode)
{
std::string sErrMsg = "";
bool bResult = true;
struct _stat buf;
int iResult = 0;
// Get data associated with "crt_stat.c":
iResult = _stat( sFilename.c_str(), &buf );
// Check if statistics are valid:
if( iResult != 0 )
{
switch (errno)
{
case ENOENT:
sErrMsg = "File: " + sFilename + " not found.";
break;
case EINVAL:
sErrMsg = "Invalid parameter to _stat(filename, &buf).";
break;
default:
/* Should never be reached. */
sErrMsg = "Unexpected error in _stat(filename, &buf).";
}
throw std::runtime_error(sErrMsg);
}
else
{
if((iOpenmode & CFile::Read) && (!(buf.st_mode & S_IREAD)))
{
bResult = false;
}
if((iOpenmode & CFile::Write) && (!(buf.st_mode & S_IWRITE)))
{
bResult = false;
}
}
return bResult;
}
The only way to get 'false' for permission is to set the file's attribute 'read only'. Instead of this, set the security properties of the user (reject writing and reading) will get 'true' for checkPermissions(...). How to check both, the attributes and the user permissions for Windows?
Rumo
_stat is a function that is not native to Windows. It's a helper function to ease the porting of UNIX programs to Windows. But the UNIX file model just doesn't apply to Windows, so not all fields make sense. For instance, Windows has real ACL's, not rwx bits. There's just no way to fit all the ACL information in st_mode.
If you want to test ACL permissions, the proper way is to just try: call CreateFile() and check GetLastError(). Trying to get file permissions up front is not reliable as they can change at any time.
If we're talking about the same _stat() it's pretty clear from this MSDN article exactly what it does. Basically, you supply it a path to a file in question and a pointer to a _stat struct and it will dump the permissions to the struct if it returns 0.
The example C++ code in the article is pretty good.
As for testing user permissions, IsUserAnAdmin() does the job pretty well. You may be able to use this MSDN article for a different approach.
I hope this helps!