Comment 46 for bug 326768

that patch is still wrong.

The first time a HUP is received, we run the code in the trap
and call wait which will wait for both the refresh command and
the mysqld one.

But we won't return from that trap until mysqld dies, and in the
trap the HUP signal is blocked, which means any subsequent
HUP will not be handled.

A better way could be to implement some proper event handling as in:

trap : HUP INT QUIT TERM
while :; do
  action=
  mysqld ... &
  while :; do
    signal=NONE
    wait || signal=$(kill -l "$?")

    case $signal in
      (INT|TERM|QUIT) mysqladmin ... shutdown; exit;;
      (HUP) mysqladmin ... refresh;;
      (NONE) break;; # mysqld died
      (*) unexpected ... die;;
    esac
  esac
done