[Bug 824] \0 character is added to REG_MULTI_SZ registry values

http://bugs.winehq.org/show_bug.cgi?id=824

--- Comment #11 from Michal Piaskowski   2008-01-04 18:04:55 ---
Created an attachment (id=10039)
 --> (http://bugs.winehq.org/attachment.cgi?id=10039)
Change the way REG_MULTI_SZ is saved

As it have been said already the problem is that wine stores REG_MULTI_SZ as
null terminated string and sometimes looses information about data length.
Without this information wine can't tell if the original string was null
terminated or not.

To make things more complicated Windows XP (as well as wine) whenever
RegSetValueEx( HKEY hkey, LPCSTR name, DWORD reserved, DWORD type,
                            CONST BYTE *data, DWORD count )
is called with data pointing to a string which isn't null terminated
system will check if data[count] is null. If it is then it will assume that the
user forgot about the ending /0 and will save count+1 bytes, but if data[count]
isn't null it will save only count bytes.

I have tested following calls on windows xp and wine:

RegSetValueEx(myKey,"321\0 len=4",0,REG_MULTI_SZ,(const BYTE
*)"321",4);
        RegSetValueEx(myKey,"321\0 len=3",0,REG_MULTI_SZ,(const BYTE
*)"321",3);
        RegSetValueEx(myKey,"321\0 len=2",0,REG_MULTI_SZ,(const BYTE
*)"321",2);
        RegSetValueEx(myKey,"321\0 len=1",0,REG_MULTI_SZ,(const BYTE
*)"321",1);
        RegSetValueEx(myKey,"321\0 len=0",0,REG_MULTI_SZ,(const BYTE
*)"321",0);

This is the result of exporting these keys on Windows XP

"321\0 len=4"=hex(7):33,00,32,00,31,00,00,00
"321\0 len=3"=hex(7):33,00,32,00,31,00,00,00
"321\0 len=2"=hex(7):33,00,32,00
"321\0 len=1"=hex(7):33,00
"321\0 len=0"=hex(7):

This is how wine stores it in ~/.wine/user.reg

"321\0 len=0"=str(7):""
"321\0 len=1"=str(7):"3"
"321\0 len=2"=str(7):"32"
"321\0 len=3"=str(7):"321"
"321\0 len=4"=str(7):"321"

And this is how wine exports it:

"321\0 len=0"=hex(7):00

"321\0 len=1"=hex(7):33,00

"321\0 len=2"=hex(7):33,32,00

"321\0 len=3"=hex(7):33,32,31,00

"321\0 len=4"=hex(7):33,32,31,00

I made a simple patch that changes the way wine stores REG_MULTI_SZ from str(7)
to hex(7).

After applying that patch Wine stores those values as:

"321\0 len=0"=hex(7):
"321\0 len=1"=hex(7):33,00
"321\0 len=2"=hex(7):33,00,32,00
"321\0 len=3"=hex(7):33,00,32,00,31,00,00,00
"321\0 len=4"=hex(7):33,00,32,00,31,00,00,00

And regedit exports it this way:

"321\0 len=0"=hex(7):

"321\0 len=1"=hex(7):33

"321\0 len=2"=hex(7):33,32

"321\0 len=3"=hex(7):33,32,31,00

"321\0 len=4"=hex(7):33,32,31,00