Willy Tarreau bb1caff70f MINOR: fd: add a new "exported" flag and use it for all regular listeners ... This new flag will be used to mark FDs that must be passed to any future process across the CLI's "_getsocks" command. The scheme here is quite complex and full of special cases: - FDs inherited from parent processes are *not* exported this way, as they are supposed to instead be passed by the master process itself across reloads. However such FDs ought never to be paused otherwise this would disrupt the socket in the parent process as well; - FDs resulting from a "bind" performed over a socket pair, which are in fact one side of a socket pair passed inside another control socket pair must not be passed either. Since all of them are used the same way, for now it's enough never to put this "exported" flag to FDs bound by the socketpair code. - FDs belonging to temporary listeners (e.g. a passive FTP data port) must not be passed either. Fortunately we don't have such FDs yet. - the rest of the listeners for now are made of TCP, UNIX stream, ABNS sockets and are exportable, so they get the flag. - UDP listeners were wrongly created as listeners and are not suitable here. Their FDs should be passed but for now they are not since the client doesn't even distinguish the SO_TYPE of the retrieved sockets. In addition, it's important to keep in mind that: - inherited FDs may never be closed in master process but may be closed in worker processes if the service is shut down (useless since still bound, but technically possible) ; - inherited FDs may not be disabled ; - exported FDs may be disabled because the caller will perform the subsequent listen() on them. However that might not work for all OSes - exported FDs may be closed, it just means the service was shut down from the worker, and will be rebound in the new process. This implies that we have to disable exported on close(). => as such, contrary to an apparently obvious equivalence, the "exported" status doesn't imply anything regarding the ability to close a listener's FD or not.		2020-08-26 18:33:52 +02:00
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haproxy	MINOR: fd: add a new "exported" flag and use it for all regular listeners	2020-08-26 18:33:52 +02:00
import	CLEANUP: assorted typo fixes in the code and comments	2020-06-26 11:27:28 +02:00