Possibly unsafe SIGHUP handler

[marekm72]

Inspired by the analysis of the RegreSSHion vulnerability, I've just looked at signal handlers in accel-pppd.
If logging to files is configured, SIGHUP handler to re-open them may call potentially async-signal-unsafe functions.
Probably not easily exploitable, as remote attacker has no control over when SIGHUP is sent, but if logrotate is configured to send SIGHUP to re-open log files after rotating them at predictable time (say from a cron job), someone might get lucky.
General recommendation is for the signal handler to only set a flag and return, then check that flag in the main process, and if set then call the functions to re-open log files synchronously (not from the signal handler directly).