I want to get the install date of product:
DWORD max = 255;
WCHAR buffer[255];
std::wstring guidWString = S::WstrToStr(subKeys[i]); //from array of std::string
LPCWSTR guid = guidWString.c_str();
int err = MsiGetProductInfo(guid, INSTALLPROPERTY_INSTALLDATE, buffer, &max);
if(err == ERROR_SUCCESS){ //never success :(
info.date = S::WstrToStr(std::wstring(buffer));
}
But I always get the error code 87 (*ERROR_INVALID_PARAMETER*).
I don't see anything "invalid" here, according to the documentation:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa370130%28v=vs.85%29.aspx
I have checked that:
All variables are of good types, buffer size (DWORD max) is not null, equal to the size of my buffer.
I use a function to convert std::string (I have my GUID in std::string) to std::wstring (under debugger, all looks good, conversion works in many other places in code that use WinAPI and std::wstring).
I have tried with different GUID, all of them exists and works for asking register "manually". MsiGetProductInfo() returns that error ALWAYS.
I have also tried to just write GUID in code (L"{GUID-GO-EXACTLY-HERE}"), with the same result.
I just don't know where the problem is?
Related
As a starting C++ programmer I want to set a value in the windows registry. I created this textbook implementation to accomplish this, but I always get error 998 back. I guess I am missing something very simple and straightforward, but I can't figure out what it is.
Running this code as a regular user or administrator makes no difference.
#define LEDPORT 3
#define SUBKEY "SOFTWARE\\PATH\\OTHERPATH\\"
HKEY key;
if(RegCreateKey(HKEY_LOCAL_MACHINE, TEXT(SUBKEY), &key) == ERROR_SUCCESS)
{
HKEY createKey;
DWORD value = LEDPORT;
if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, TEXT(SUBKEY), NULL, KEY_ALL_ACCESS, &createKey) == ERROR_SUCCESS){
// retVal returns error 998 and the value isn't set
int retVal = RegSetValueEx(createKey, TEXT("PortNumber"), NULL, REG_DWORD, (BYTE *)value, sizeof(value));
RegCloseKey(createKey);
}
}
In effect this creates the mentioned key at LocalMachine\Software\Path\OtherPath but the DWORD value "PortNumber" isnt.
Again, I think it is something straightforward, but I spend a couple of hours of thinking what it could be and I can't figure it out.
Error code 998 converted into human-readable is Invalid access to memory location. The reason is your cast (BYTE*)value, reinterpreting the value 3 (LEDPORT) as an address. (BYTE*)&value fixes your immediate problem.
I created a simple function:
std::wstring GetRegKey(const std::string& location, const std::string& name){
const int valueLength = 10240;
auto platformFlag = KEY_WOW64_64KEY;
HKEY key;
TCHAR value[valueLength];
DWORD bufLen = valueLength*sizeof(TCHAR);
long ret;
ret = RegOpenKeyExA(HKEY_LOCAL_MACHINE, location.c_str(), 0, KEY_READ | platformFlag, &key);
if( ret != ERROR_SUCCESS ){
return std::wstring();
}
ret = RegQueryValueExA(key, name.c_str(), NULL, NULL, (LPBYTE) value, &bufLen);
RegCloseKey(key);
if ( (ret != ERROR_SUCCESS) || (bufLen > valueLength*sizeof(TCHAR)) ){
return std::wstring();
}
std::wstring stringValue(value, (size_t)bufLen - 1);
size_t i = stringValue.length();
while( i > 0 && stringValue[i-1] == '\0' ){
--i;
}
return stringValue;
}
And I call it like auto result = GetRegKey("SOFTWARE\\Microsoft\\Cryptography", "MachineGuid");
yet string looks like
㤴ㄷ㤵戰㌭㉣ⴱ㔴㍥㤭慣ⴹ㍥摢㘵〴㉡ㄵ\0009ca9-e3bd5640a251
not like RegEdit
4971590b-3c21-45e3-9ca9-e3bd5640a251
So I wonder what shall be done to get a correct representation of MachineGuid in C++?
RegQueryValueExA is an ANSI wrapper around the Unicode version since Windows NT. When building on a Unicode version of Windows, it not only converts the the lpValueName to a LPCWSTR, but it will also convert the lpData retrieved from the registry to an LPWSTR before returning.
MSDN has the following to say:
If the data has the REG_SZ, REG_MULTI_SZ or REG_EXPAND_SZ type, and
the ANSI version of this function is used (either by explicitly
calling RegQueryValueExA or by not defining UNICODE before including
the Windows.h file), this function converts the stored Unicode string
to an ANSI string before copying it to the buffer pointed to by
lpData.
Your problem is that you are populating the lpData, which holds TCHARs (WCHAR on Unicode versions of Windows) with an ANSI string.
The garbled string that you see is a result of 2 ANSI chars being used to populate a single wchar_t. That explains the Asian characters. The portion that looks like the end of the GUID is because the print function blew past the terminating null since it was only one byte and began printing what is probably a portion of the buffer that was used by RegQueryValueExA before converting to ANSI.
To solve the problem, either stick entirely to Unicode, or to ANSI (if you are brave enough to continue using ANSI in the year 2014), or be very careful about your conversions. I would change GetRegKey to accept wstrings and use RegQueryValueExW instead, but that is a matter of preference and what sort of code you plan on using this in.
(Also, I would recommend you have someone review this code since there are a number of oddities in the error checking, and a hard coded buffer size.)
I write filtering system and use Winsock2 LSP.
In WSPConnect I need to compare executable filename of process with harcoded Unicode String.
I do:
LPWSTR moduleName = {0};
GetModuleFileNameEx (GetCurrentProcess(),0,moduleName,_MAX_FNAME );
LPWSTR mn = L"redirect.exe";
if (lstrcmp (moduleName, mn) == 0){ ...some code there...}
What I am doing wrong?
You should compare "case-insensitive": lstrcmpi
You need to pass a correct char array...
Also you should always check the result values of function calls!
Also you should not use the TCHAR version of GetModuleFileNameEx if you explicit use wchar_t => GetModuleFileNameExW!
Also you should use the method GetModuleFileNameW if you want to get the name of the current process! This is more reliable!
ALso you should use MAX_PATH instead of _MAX_FNAME, because the method might also return the full path!
Also be sure that your string is correctly NUL-terminated!
Also you must be aware that the returned path might contain the full path, so comparing with the process name does never match...
Also you must be aware that the path might contion the short file name! (not in your case, because the name is not longer than 8 characters; but if you compare it with "MyExecutable.exe" you also must compare with the short file name; see GetShortPathName
The code part should now look like:
WCHAR moduleName[MAX_PATH+1];
if (GetModuleFileNameW (NULL, moduleName, MAX_PATH) != 0)
{
moduleName[MAX_PATH] = 0;
LPWSTR mn = L"redirect.exe";
int len = lstrlen(moduleName);
int lenmn = lstrlen(mn);
if (len > lenmn)
{
if (lstrcmpi (&moduleName[len-lenmn], mn) == 0){ ...some code there...}
}
}
You need to declare storage space, just a pointer is not enough
LPWSTR moduleName = {0};
GetModuleFileNameEx (GetCurrentProcess(),0,moduleName,_MAX_FNAME );
should be
TCHAR moduleName[_MAX_PATH];
GetModuleFileNameEx(GetCurrentProcess(), 0, moduleName, _countof(moduleName));
and use case-insensitive lstrcmpi().
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
How to compare strings
I want to Compare to registry string values and if they were the same an messagebox appears
Currently I'm using this functions , It returns the value correctly but whenever I want to compare them, The compare result is always wrong
char* GetRegistry(char* StringName)
{
DWORD dwType = REG_SZ;
HKEY hKey = 0;
char value[1024];
DWORD value_length = 1024;
const char* subkey = "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\MCI\\Player";
RegOpenKey(HKEY_LOCAL_MACHINE,subkey,&hKey);
RegQueryValueEx(hKey, StringName, NULL, &dwType, (LPBYTE)&value, &value_length);
return value;
}
I use this to compare them
if (GetRegistry("First") == GetRegistry("Second"))
{
MessageBox(NULL,":|",":|",1);
}
But the MessageBox appears how ever The values are different
Any help is appreciated.
By using std::string, comparison would behave as you expected. Also that would fix another bug that the function returns a pointer to a local buffer.
std::string GetRegistry(const char* StringName)
{
....
return std::string(value);
}
GetRegistry() returns a char*, so you are actually comparing pointers with operator==.
You should use strcmp() to do raw C-like char* string comparisons, or better use a robust C++ string class, like CString or std::[w]string.
Here is a possible rewrite of your function using ATL's CString:
#include <atlbase.h>
#include <atlstr.h>
CString GetRegistry(LPCTSTR pszValueName)
{
// Try open registry key
HKEY hKey = NULL;
LPCTSTR pszSubkey = _T("SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\MCI Extensions");
if ( RegOpenKey(HKEY_LOCAL_MACHINE, pszSubkey, &hKey) != ERROR_SUCCESS )
{
// Error:
// throw an exception or something...
//
// (In production code a custom C++ exception
// derived from std::runtime_error could be used)
AtlThrowLastWin32();
}
// Buffer to store string read from registry
TCHAR szValue[1024];
DWORD cbValueLength = sizeof(szValue);
// Query string value
if ( RegQueryValueEx(
hKey,
pszValueName,
NULL,
NULL,
reinterpret_cast<LPBYTE>(&szValue),
&cbValueLength)
!= ERROR_SUCCESS )
{
// Error
// throw an exception or something...
AtlThrowLastWin32();
}
// Create a CString from the value buffer
return CString(szValue);
}
And then you can call it like this:
if ( GetRegistry(_T("First")) == GetRegistry(_T("Second")) )
...
Note that this code will compile in both ANSI/MBCS and Unicode builds (it's based on Win32 TCHAR model).
You have a couple of problems with this source code.
First of all you have a function with a local variable, a variable on the stack, which is returning the address of that variable yet when the function returns, the variable disappears and the address is no longer valid.
The next problem is that you are not comparing the character strings. You are instead comparing the address returned by the function and if you get lucky, the address could be the same. Since you are calling the function twice in succession, you are getting lucky so the address is the same.
I suggest you do the following: (1) create two local character strings in your function which is calling the function GetRegistry() and (2) modify the GetRegistry() function so that it uses those buffers rather than its own. So the code would look something like:
char registryEntryOne[1024];
char registryEntryTwo[1024];
DWORD dwRegistryEntryOneLen;
DWORD dwRegistryEntryTwoLen;
registryEntryOne[0] = 0; // init the registry entry to zero length string
registryEntryTwo[0] = 0;
dwRegistryEntryOneLen = sizeof(registryEntryOne);
GetRegistry ("First", registryEntryOne, &dwRegistryEntryOneLen);
dwRegistryEntryTwoLen = sizeof(registryEntryTwo);
GetRegistry ("Second", registryEntryTwo, &dwRegistryEntryTwoLen);
// two strings are equal if:
// the lengths are the same
// at least one of the lengths is non-zero
// the bytes are the same in the same order
if (dwRegistryEntryOneLen && dwRegistryEntryOneLen == dwRegistryEntryTwoLen && memcmp (registryEntryOne, registryEntryTwo, dwRegistryEntryOneLen) == 0) {
// strings are equal
} else {
// strings are not equal
}
The GetRegistry() function would look something like:
char* GetRegistry(char* StringName, char *valueBuffer, DWORD *value_length)
{
DWORD dwType = REG_SZ;
HKEY hKey = 0;
const char* subkey = "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\MCI\\Player";
RegOpenKey(HKEY_LOCAL_MACHINE,subkey,&hKey);
RegQueryValueEx(hKey, StringName, NULL, &dwType, (LPBYTE)valueBuffer, value_length);
return valueBuffer;
}
The following piece of code seems to unreliably execute and after and undeterministic time it will fail with error code 234 at the RegEnumValue function.
I have not written this code, I am merely trying to debug it. I know there is an issue with doing RegEnumValue and then deleting keys in the while loop.
I am trying to figure out first, why it is throwing this 234 error at seemingly random points, as in, it is never after a consistent number of loop iterations or anything like that.
From what I have seen it fails to fill its name buffer, but this buffer is by no means too small for its purpose, so I don't understand how it could fail??
Could someone please advice on getting rid of this 234 error thrown by the RegEnumValue funciton?
HKEY key;
DWORD dw;
int idx;
char name[8192];
DWORD namesize=4096;
std::string m_path = "SOFTWARE\\Company\\Server 4.0";
if (RegOpenKeyEx(HKEY_LOCAL_MACHINE,m_path.c_str(),0,KEY_ALL_ACCESS,&key) == ERROR_SUCCESS)
{
bool error=false;
idx=0;
long result;
long delresult;
while (true)
{
result = RegEnumValue(key,idx,(char*)name,&namesize,NULL,NULL,NULL,NULL);
if (result == ERROR_SUCCESS && !error){
delresult = RegDeleteValue(key,name);
if (delresult != ERROR_SUCCESS)
error = true;
idx++;
}
else
{
break;
}
}
RegCloseKey(key);
}
There are some errors in your code:
The 4-th parameter of RegEnumValue (the namesize) is in-out parameter. So you have to reset namesize to sizeof(name)/sizeof(name[0]) (in case of the usage char type it is just sizeof(name)) inside the while loop before every call of RegEnumValue. It's the main error in your program.
If you don't want to have ERROR_MORE_DATA error any time you have the buffer having 32,767 characters. It is the maximum size of name the the regitry value (see documentation of RegEnumValue).
It is not good to use KEY_ALL_ACCESS in the RegOpenKeyEx. I'll recomend you to change it to KEY_QUERY_VALUE | KEY_SET_VALUE. It is not a real error, but depends on your environment it could be.
It if better to use UNICODE version of all this functions to speed-up a little the code.
UPDATED: Only small comment about the usage of the UNICODE version. Intern Windows work with UNICODE characters. So usage of non-Unicode version of RegEnumValue si more slow because at the evry call a new UICODE memeory block will be allocated and converted to ANSI/Multi-byte. Moreover if you will has a value name written in a language which can't be converted in you Windows ANSI code page (Chinese, Japanese and so on) and some characters will be replaced to '?' (see WC_DEFAULTCHAR flag of WideCharToMultiByte), then it can be that the function RegDeleteValue will fail with the error code like "the value with the name is not exist".
just change the value of your fourth parameter i.e namesize from 4096 to 8192 .Always MakeSure that it should be always equal to buffer size.
The answer is at the bottom of that page:
http://msdn.microsoft.com/en-us/library/ms724865(VS.85).aspx
Please read the answer of "ERROR_MORE_DATA: lpData too small, or lpValueName too small?" question.