wchar_t handling in IDLs

[Alexander Bokovoy]

Hi!

I'm looking into some cases where printers are not accessible when
served by Samba and apparently, common issue is that they are named with
characters outside Latin-1.

According to spoolss.idl, device name in spoolss_DeviceMode struct is
presented as 

[charset(UTF16),to_null] uint16 devicename[MAXDEVICENAME];

while that is 'wchar_t devicename[32]' on Windows side.

Here is what we get for a printer with Russian letters in the name:
---------------------------------------------------------------------------------
[2011/08/26 13:13:07.800902,  9] printing/nt_printing.c:4015(get_a_printer_2)
  Unpacked printer [office-hp-p1505-prn] name [\\officesrv\HP P1505 у закупщиков] running driver [HP LaserJet P1505]
  loading DEVICEMODE
[2011/08/26 13:13:07.800980,  3] lib/charcnv.c:279(convert_string_internal)
  convert_string_internal: Conversion error: Illegal multibyte sequence(<D1>)
[2011/08/26 13:13:07.800998,  1] ../librpc/ndr/ndr.c:421(ndr_push_error)
  ndr_push_error(5): Bad character conversion
[2011/08/26 13:13:07.801014,  1] ../librpc/ndr/ndr.c:251(ndr_print_function_debug)
       spoolss_GetPrinter: struct spoolss_GetPrinter
          out: struct spoolss_GetPrinter
              info                     : *
                  info                     : union spoolss_PrinterInfo(case 2)
                  info2: struct spoolss_PrinterInfo2
                      servername               : *
                          servername               : '\\192.168.8.2'
                      printername              : *
                          printername              : '\\192.168.8.2\HP P1505 у закупщиков'
                      sharename                : *
                          sharename                : 'office-hp-p1505-prn'
                      portname                 : *
                          portname                 : 'Samba Printer Port'
                      drivername               : *
                          drivername               : 'HP LaserJet P1505'
                      comment                  : *
                          comment                  : 'Printer HP P1505 on SERVER in Office'
                      location                 : *
                          location                 : 'Office, Server'
                      devmode                  : *
                          devmode: struct spoolss_DeviceMode
                              devicename               : '\\officesrv\HP P1505 у зак<D1>'
                              specversion              : DMSPEC_NT4_AND_ABOVE (1025)
                              driverversion            : 0x0701 (1793)
                              size                     : 0x00dc (220)
                              __driverextra_length     : 0x04d8 (1240)
                              fields                   : 0x0780ef03 (125890307)
.......
.......
------------------------------------------------------------------------------------

spoolss_DeviceMode.devicename is 32 wchar_t long. The full devicename
would be 33 wchar_t chars. As we can see, it got cut down, perhaps on
Windows side. I wonder how should we deal with such broken multi-byte
strings? Should the devicename cut down to 32 wchar_t using the same
algorithm everywhere so that regardless how it came, we are capable to
recognize it and handle without conversion error?

-- 
/ Alexander Bokovoy