From: Michal Sojka <sojkam1@fel.cvut.cz>
Date: Tue, 12 Sep 2017 11:12:31 +0000 (+0200)
Subject: uloop: Fix race condition in SIGCHLD handling
X-Git-Url: http://git.archive.openwrt.org/?p=project%2Flibubox.git;a=commitdiff_plain;h=7a1057604ed2ad83434ed3be03728065b14a5e9c;hp=7a1057604ed2ad83434ed3be03728065b14a5e9c;ds=sidebyside

uloop: Fix race condition in SIGCHLD handling

When uloop_process_add() is called outside of uloop_run(), i.e. not
from a callback (which is the case of at least utrace and ujail),
child events can be missed. The reason is that when SIGCHILD handler
is installed in uloop_run(), after the uloop_process_add() is called,
then an initial signal could be missed.

Commit 4e3a47a ("uloop: use a waker for notifying sigchld and loop
cancel events", 2016-06-09) solved a similar problem and introduced
uloop_init() but forgot to move a call to uloop_setup_signals() there.
This is what this commit does.

Now, uloop_process_add() can be called any time after uloop_init()
without missing any event.

Signed-off-by: Michal Sojka <sojkam1@fel.cvut.cz>
Acked-by: Yousong Zhou <yszhou4tech@gmail.com>
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