diff --git a/man/daemon.xml b/man/daemon.xml
index 7724bb4e08d..41da01943c6 100644
--- a/man/daemon.xml
+++ b/man/daemon.xml
@@ -77,9 +77,10 @@
setsid() to detach from any terminal and
create an independent session.
- In the child, call fork()
- again, to ensure that the daemon can never re-acquire a
- terminal again.
+ In the child, call fork() again, to ensure that the daemon can
+ never re-acquire a terminal again. (This relevant if the program — and all its dependencies — does
+ not carefully specify `O_NOCTTY` on each and every single `open()` call that might potentially open a
+ TTY device node.)
Call exit() in the first
child, so that only the second child (the actual daemon
@@ -244,6 +245,10 @@
and
systemd.exec5.
+ As new-style daemons are invoked without a controlling TTY (but as their own session
+ leaders) care should be taken to always specify `O_NOCTTY` on `open()` calls that possibly reference
+ a TTY device node, so that no controlling TTY is accidentally acquired.
+
These recommendations are similar but not identical to the