Change isc_entropy_usebestsource() to have saner semantics:
- If an invalid file is specified, an error will be returned instead of the
keyboard being used.
- If no file is specified but a random device is present, the keyboard will
be used if there is an error opening the random device.
- ISC_ENTROPY_KEYBOARDYES indicates that the keyboard should be the
only device used. Otherwise, passing '-r keyboard' is meaningless
on a machine with a random device, since the keyboard will not be used.
Change the callers in the dnssec tools and rndc-confgen to check for the
special file "keyboard" and call isc_entropy_usebestsource() with the right set
of parameters.
used because of the lack of a suitable random device
was not being printed.
wantkeyboard was always being set to true just before setting up the keyboard
callback, rather than only being set to true if PATH_RANDOMDEV was undefined
or not able to be opened.
Mostly, several functions that take pointers as arguments, almost
always char * pointers, had those pointers qualified with "const".
Those that returned pointers to previously const-qualified arguments
had their return values qualified as const. Some structure members
were qualified as const to retain that attribute from the variables
from which they were assigned.
Minor other ISC style cleanups.
