The terminating nul character ('\0') could be written outside the boundary of
the buffer which is used to read characters. If "sizeof(buffer)" characters
are read, the resulting value must not be used as index, because that's an off
by one.

Read sizeof(buffer)-1 bytes instead.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>

refactor vol_perc to not depend on alsa libraries

several bugfixes and general improvements, see commits below.

Add a "uname -r" feature to see which kernel is running