mirror of
https://github.com/gentoo-mirror/gentoo.git
synced 2026-08-24 06:48:18 -07:00
0edb96f7d0
Backport the upstream pull request that disables signalfd by default, as it turned out to cause lots of unexpected breakage. In particular, app-misc/tmux was broken and it can't be trivially fixed. Signed-off-by: Michał Górny <mgorny@gentoo.org>
153 lines
4.6 KiB
Diff
153 lines
4.6 KiB
Diff
From 594ab34f1dfc73db85e8f95ec51892cadecaa76c Mon Sep 17 00:00:00 2001
|
|
From: Azat Khuzhin <azat@libevent.org>
|
|
Date: Mon, 10 Jul 2023 10:40:49 +0200
|
|
Subject: [PATCH] Disable signalfd by default
|
|
|
|
signalfd may behave differently to sigaction/signal, so to avoid
|
|
breaking libevent users (like [1], [2]) disable it by default.
|
|
|
|
[1]: https://github.com/tmux/tmux/pull/3621
|
|
[2]: https://github.com/tmux/tmux/pull/3626
|
|
|
|
Also signalfd is not that perfect:
|
|
- you need to SIG_BLOCK the signal before
|
|
- blocked signals are not reset on exec
|
|
- blocked signals are allowed to coalesce - so in case of multiple
|
|
signals sent you may get the signal only once (ok for most of the
|
|
signals, but may be a problem for SIGCHLD, though you may call
|
|
waitpid() in a loop or use pidfd)
|
|
- and also one implementation problem -
|
|
sigprocmask is unspecified in a multithreaded process
|
|
|
|
Refs:
|
|
- https://lwn.net/Articles/415684/
|
|
- https://ldpreload.com/blog/signalfd-is-useless
|
|
|
|
Refs: https://github.com/libevent/libevent/issues/1460
|
|
Refs: #1342 (cc @dmantipov)
|
|
---
|
|
CMakeLists.txt | 1 +
|
|
include/event2/event.h | 6 ++++--
|
|
signalfd.c | 4 ++--
|
|
test/include.am | 2 ++
|
|
test/test.sh | 11 +++++++++--
|
|
5 files changed, 18 insertions(+), 6 deletions(-)
|
|
|
|
diff --git a/CMakeLists.txt b/CMakeLists.txt
|
|
index cd41d16e57..9c402ec0c1 100644
|
|
--- a/CMakeLists.txt
|
|
+++ b/CMakeLists.txt
|
|
@@ -1509,6 +1509,7 @@ if (NOT EVENT__DISABLE_TESTS)
|
|
else()
|
|
add_backend_test(${BACKEND} "${BACKEND_ENV_VARS}")
|
|
endif()
|
|
+ add_backend_test(signalfd_${BACKEND} "${BACKEND_ENV_VARS};EVENT_USE_SIGNALFD=1")
|
|
endforeach()
|
|
|
|
#
|
|
diff --git a/include/event2/event.h b/include/event2/event.h
|
|
index 384a84178b..9b971edf1d 100644
|
|
--- a/include/event2/event.h
|
|
+++ b/include/event2/event.h
|
|
@@ -599,9 +599,11 @@ enum event_base_config_flag {
|
|
*/
|
|
EVENT_BASE_FLAG_EPOLL_DISALLOW_TIMERFD = 0x40,
|
|
|
|
- /** Do not use signalfd(2) to handle signals even if supported.
|
|
+ /** Use signalfd(2) to handle signals over sigaction/signal.
|
|
+ *
|
|
+ * But note, that in some edge cases signalfd() may works differently.
|
|
*/
|
|
- EVENT_BASE_FLAG_DISALLOW_SIGNALFD = 0x80,
|
|
+ EVENT_BASE_FLAG_USE_SIGNALFD = 0x80,
|
|
};
|
|
|
|
/**
|
|
diff --git a/signalfd.c b/signalfd.c
|
|
index 376a04d539..ed31014e5f 100644
|
|
--- a/signalfd.c
|
|
+++ b/signalfd.c
|
|
@@ -205,8 +205,8 @@ sigfd_del(struct event_base *base, int signo, short old, short events, void *p)
|
|
int sigfd_init_(struct event_base *base)
|
|
{
|
|
EVUTIL_ASSERT(base != NULL);
|
|
- if ((base->flags & EVENT_BASE_FLAG_DISALLOW_SIGNALFD) ||
|
|
- getenv("EVENT_DISALLOW_SIGNALFD"))
|
|
+ if (!(base->flags & EVENT_BASE_FLAG_USE_SIGNALFD) &&
|
|
+ !getenv("EVENT_USE_SIGNALFD"))
|
|
return -1;
|
|
base->evsigsel = &sigfdops;
|
|
return 0;
|
|
diff --git a/test/include.am b/test/include.am
|
|
index e061c937b7..9b50759da7 100644
|
|
--- a/test/include.am
|
|
+++ b/test/include.am
|
|
@@ -80,6 +80,8 @@ test_runner_changelist: $(top_srcdir)/test/test.sh
|
|
$(top_srcdir)/test/test.sh -b "" -c
|
|
test_runner_timerfd_changelist: $(top_srcdir)/test/test.sh
|
|
$(top_srcdir)/test/test.sh -b "" -T
|
|
+test_runner_timerfd_changelist: $(top_srcdir)/test/test.sh
|
|
+ $(top_srcdir)/test/test.sh -b "" -S
|
|
|
|
DISTCLEANFILES += test/regress.gen.c test/regress.gen.h
|
|
|
|
diff --git a/test/test.sh b/test/test.sh
|
|
index dfdd2bf098..79362888c5 100755
|
|
--- a/test/test.sh
|
|
+++ b/test/test.sh
|
|
@@ -50,6 +50,7 @@ setup () {
|
|
done
|
|
unset EVENT_EPOLL_USE_CHANGELIST
|
|
unset EVENT_PRECISE_TIMER
|
|
+ unset EVENT_USE_SIGNALFD
|
|
}
|
|
|
|
announce () {
|
|
@@ -138,10 +139,12 @@ do_test() {
|
|
EVENT_EPOLL_USE_CHANGELIST=yes; export EVENT_EPOLL_USE_CHANGELIST
|
|
elif test "$2" = "(timerfd)" ; then
|
|
EVENT_PRECISE_TIMER=1; export EVENT_PRECISE_TIMER
|
|
+ elif test "$2" = "(signalfd)" ; then
|
|
+ EVENT_USE_SIGNALFD=1; export EVENT_USE_SIGNALFD
|
|
elif test "$2" = "(timerfd+changelist)" ; then
|
|
EVENT_EPOLL_USE_CHANGELIST=yes; export EVENT_EPOLL_USE_CHANGELIST
|
|
EVENT_PRECISE_TIMER=1; export EVENT_PRECISE_TIMER
|
|
- fi
|
|
+ fi
|
|
|
|
run_tests
|
|
}
|
|
@@ -153,6 +156,7 @@ usage()
|
|
-t - run timerfd test
|
|
-c - run changelist test
|
|
-T - run timerfd+changelist test
|
|
+ -S - run signalfd test
|
|
EOL
|
|
}
|
|
main()
|
|
@@ -161,13 +165,15 @@ main()
|
|
timerfd=0
|
|
changelist=0
|
|
timerfd_changelist=0
|
|
+ signalfd=0
|
|
|
|
- while getopts "b:tcT" c; do
|
|
+ while getopts "b:tcTS" c; do
|
|
case "$c" in
|
|
b) backends="$OPTARG";;
|
|
t) timerfd=1;;
|
|
c) changelist=1;;
|
|
T) timerfd_changelist=1;;
|
|
+ S) signalfd=1;;
|
|
?*) usage && exit 1;;
|
|
esac
|
|
done
|
|
@@ -179,6 +185,7 @@ main()
|
|
[ $timerfd_changelist -eq 0 ] || do_test EPOLL "(timerfd+changelist)"
|
|
for i in $backends; do
|
|
do_test $i
|
|
+ [ $signalfd -eq 0 ] || do_test $i "(signalfd)"
|
|
done
|
|
|
|
if test "$FAILED" = "yes"; then
|