On Sat, Mar 28, 2015 at 02:52:47PM +0100, poitr pogo wrote: (in response to the question of why s6 "prevents daemonizing") > Cannot. This is from the s6 docs. I'm not using s6. Just heard about it today.
If you want to *manage* a daemon (ie, do something when it stops, like restarting it), it's very tricky to do it reliably without having a fixed PID; "daemonizing" means close stdin/stdout/stderr, then if (fork()) exit(0); or some such thing (in other words, create a new process and exit the old one), so you do not have a fixed PID. On Linux, BSD, and older UNIX versions, this can be done thus: daemon(0,0); > Another s6 limitation - finish script must end in 3 seconds. or will be > killed. > Nice for desktop, not a server. sysvinit /etc/init.d/sendsigs actually only allows 1 second. > It used to be that an application is responsible for proper start > up/shutdown procedure, as application knows the proper way how to do > it. Init script is just a place where to hook a startup/shutdown > script to be executed when system needs to start/stop application in > some automatic way. > Now there are tools which help deamonize things. > Depending how portable they are it make the price one has to pay when > decides to use them instead of handling this yourself in the > application. My understanding is that s6 and some of the equivalent packages, such as daemontools, are fairly portable. They are generally not used as a way to offload daemonizing, but as a way to ensure that a service stays started. If you don't need that, you don't need them. > Regards > piotr Thanks, Isaac Dunham _______________________________________________ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
