Previously you would not get feedback when quotes are not terminated or
when the command is too long. Fix this by putting stderr redirection in
the shell command, before eval.
Not just the first two bytes should match, it should be the expected
length. Found the hint in dmesg after failing to retrieve the properties
file. Setting all following bytes to 0xff does not seem to affect the
output, so let's keep it like this. The original software does send an
empty buffer though (with all zeroes).
Thanks to hints from /proc/kmsg, I found the IOCTL_TRIM_CMD (0x1277)
hint. From the kmsg, the meaning of "LAF" was also found (which could be
discovered via the lafd binary too...).
The whence option for read was observed by putting 0xffffffff in the
argument and was tried because the DLL showed a fourth argument that was
always zero.
