Re: Bug#760841: pspp: [kfreebsd] random testsuite failures

[Steven Chamberlain <steven@pyro.eu.org>]

With some difficulty, I managed to reproduce the failure situation under
ktrace, so that I could diff with the successful case:

>  u8-istream-test CALL  read(0,0x640670,0x1000)
> -u8-istream-test GIO   fd 0 read 13 bytes
> -0x0000 6500 6e00 7400 7200 e900 6500 0a
> +u8-istream-test GIO   fd 0 read 14 bytes
> +0x0000 6500 6e00 7400 7200 e900 6500 0a00
>  
> -u8-istream-test RET   read 13/0xd
> +u8-istream-test RET   read 14/0xe

The size of the read from fd 0 (stdin) was different;  the last null
byte got truncated.  I don't know why that is.  The read is assumed to
be complete and it doesn't attempt to read again.

The effect is it will later decide the string is not valid UTF-16LE, so
treats it as CP1252, and doesn't properly convert it.

It seems logical this bug only happened for Little Endian encodings
(strings with Big Endian encoding will not end with a null byte).

>  u8-istream-test CALL  open(0x8012baba0,0<O_RDONLY>,<unused>0)
>  u8-istream-test NAMI  "/usr/lib/x86_64-kfreebsd-gnu/gconv/gconv-modules.cache"
>  u8-istream-test RET   open 3
> -u8-istream-test CALL  fstat(0x3,0x7fffffffcf40)
> +u8-istream-test CALL  fstat(0x3,0x7fffffffd190)
>  u8-istream-test STRU  invalid record
>  u8-istream-test RET   fstat 0
>  u8-istream-test CALL  mmap(0,0x6696,0x1<PROT_READ>,0x1<MAP_SHARED>,0x3,0)
>  u8-istream-test RET   mmap 34368200704/0x800812000
>  u8-istream-test CALL  close(0x3)
>  u8-istream-test RET   close 0
> -u8-istream-test CALL  open(0x6499c0,0x100000<O_CLOEXEC>,<unused>0)
> -u8-istream-test NAMI  "/usr/lib/x86_64-kfreebsd-gnu/gconv/CP1252.so"
> +u8-istream-test CALL  open(0x6417d0,0x100000<O_CLOEXEC>,<unused>0)
> +u8-istream-test NAMI  "/usr/lib/x86_64-kfreebsd-gnu/gconv/UTF-16.so"

Regards,
-- 
Steven Chamberlain
steven@pyro.eu.org