lib: hard-fail creating threads before fork()

Creating any threads before we fork() into the background (if `-d` is
given) is an extremely dangerous footgun;  the threads are created in
the parent and terminated when that exits.

This is extra dangerous because while testing, you'd often run the
daemon in foreground without `-d`, and everything works as expected.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/libfrr.h b/lib/libfrr.h
index 47ded8f313..3dc5d7af81 100644
--- a/lib/libfrr.h
+++ b/lib/libfrr.h
@@ -172,6 +172,8 @@ extern const char frr_scriptdir[];
 
 extern char frr_protoname[];
 extern char frr_protonameinst[];
+/* always set in the spot where we *would* fork even if we don't do so */
+extern bool frr_is_after_fork;
 
 extern bool debug_memstats_at_exit;