The corresponding function 'zpool_get_history' in libzfs would printing
an error messages only when the ioctl call failed.
Add missing error reporting, specifically memory allocation failures
and error from 'zpool_history_unpack'.
Also avoid possibly reading of uninitialized 'err' variable in case
the requested offset pasts EOF.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Damian Szuberski <szuberskidamian@gmail.com>
Signed-off-by: WHR <msl0000023508@gmail.com>
Issue #13322Closes#13320
4dced31b98