IShellLink - how to get the original target path - windows

Question

I created a shortcut in a Windows PC with a target path of:
C:\Users\b\Desktop\New Text Document.txt
Then I copied the shortcut to another PC with a different user name, and I want to retrieve the original target path.
If you open the shortcut file with a text editor, you can see the original path is preserved, so the goal is definitely possible.
The following code does not work, despite the presence of SLGP_RAWPATH. It outputs:
C:\Users\a\Desktop\New Text Document.txt
It is changing the user folder name to the one associated with the running program.
I understand that the problem is not about environment variables, because no environment variable name can be seen in the file. But I can't find any documentation about this auto-relocation behavior.
IShellLinkW*lnk;
if (CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER, IID_IShellLinkW, (LPVOID*)&lnk) == 0){
IPersistFile* file;
if (lnk->QueryInterface(IID_IPersistFile, (void**)&file) == 0){
if (file->Load(L"shortcut", 0) == 0){
wchar_t path[MAX_PATH];
if (lnk->GetPath(path, _countof(path), 0, SLGP_RAWPATH) == 0){
_putws(path);
}
IShellLinkDataList* sdl;
if (lnk->QueryInterface(IID_IShellLinkDataList, (void**)&sdl) == 0){
EXP_SZ_LINK* lnkData;
if (sdl->CopyDataBlock(EXP_SZ_LINK_SIG, (void**)&lnkData) == 0){
_putws(lnkData->swzTarget);
LocalFree(lnkData);
}
sdl->Release();
}
}
file->Release();
}
lnk->Release();
}

Answer 1

The Windows Shell Link class implements a property store, so you can get access to this with code like this (with ATL smart pointers):
int main()
{
// note: error checking omitted!
CoInitialize(NULL);
{
CComPtr<IShellLink> link;
link.CoCreateInstance(CLSID_ShellLink);
CComPtr<IPersistFile> file;
link->QueryInterface(&file);
file->Load(L"shortcut", STGM_READ);
// get the property store
CComPtr<IPropertyStore> ps;
link->QueryInterface(&ps);
// dump all properties
DWORD count = 0;
ps->GetCount(&count);
for (DWORD i = 0; i < count; i++)
{
PROPERTYKEY pk;
ps->GetAt(i, &pk);
// get property's canonical name from pk
CComHeapPtr<wchar_t> name;
PSGetNameFromPropertyKey(pk, &name);
PROPVARIANT pv;
PropVariantInit(&pv);
ps->GetValue(pk, &pv);
// convert PropVariants to a string to be able to display
CComHeapPtr<wchar_t> valueAsString;
PropVariantToStringAlloc(pv, &valueAsString); // propvarutil.h
wprintf(L"%s: %s\n", name, valueAsString);
PropVariantClear(&pv);
}
}
CoUninitialize();
return 0;
}
It will output this:
System.ItemNameDisplay: New Text Document.txt
System.DateCreated: 2021/06/03:14:45:30.000
System.Size: 0
System.ItemTypeText: Text Document
System.DateModified: 2021/06/03:14:45:29.777
System.ParsingPath: C:\Users\b\Desktop\New Text Document.txt
System.VolumeId: {E506CEB2-0000-0000-0000-300300000000}
System.ItemFolderPathDisplay: C:\Users\b\Desktop
So, you're looking for System.ParsingPath, which you can get directly like this:
...
ps->GetValue(PKEY_ParsingPath, &pv); // propkey.h
...

Answer 2

Your shortcut is a .lnk file, just without the .lnk file extension present. According to Microsoft's latest "Shell Link (.LNK) Binary File Format" documentation, your shortcut appears to be configured as a relative file target. The relative name is just New Text Document.txt. I didn't dig into the file too much, but I'm guessing that it is relative to the system's Desktop folder, so it will take on whatever the actual Desktop folder of the current PC is. Which would explain why querying the target changes the relative root from C:\Users\b\Desktop to C:\Users\a\Desktop when you change PCs.
As for being able to query the original target C:\Users\b\Desktop\New Text Document.txt, that I don't know. It is also present in the file, so in theory there should be a way to query it, but I don't know which field it is in, without taking the time to fully decode this file. You should try writing your own decoder, using the above documentation.