BUG/MINOR: systemd: always restore signals before execve()

Since signals are inherited, we must restore them before calling execve()
and intercept them again after a failed execve(). In order to cleanly deal
with the SIGUSR2/SIGHUP loops where we re-exec the wrapper, we ignore these
two signals during a re-exec, and restore them to defaults when spawning
haproxy.

This should be backported to 1.6 and 1.5.
(cherry picked from commit 4351ea61fbddf88c960179d60b0e0f1b090f0b70)
(cherry picked from commit 7a7eada6f4ecfc54325a18cf20c3035994a901c4)
1 file changed