On 26/06/2025 09:53, Carlo Marcelo Arenas Belón via GitGitGadget wrote:
From: =?UTF-8?q?Carlo=20Marcelo=20Arenas=20Bel=C3=B3n?= <carenas@xxxxxxxxx>
If the setup for the SIGCHLD signal handler sets SA_RESTART, poll()
might not return with -1 and set errno to EINTR when a signal is
received.
Since the logic to reap zombie childs relies on those interruptions
make sure to explicitly disable SA_RESTART around this function.
Given "git daemon" seems to have been designed with the assumption that
long running system calls can fail with EINTR I don't know why this
series is trying to use SA_RESTART in the first place.
Thanks
Phillip
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@xxxxxxxxx>
---
daemon.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/daemon.c b/daemon.c
index 155b2e180167..7e29c03e313f 100644
--- a/daemon.c
+++ b/daemon.c
@@ -1116,6 +1116,25 @@ static void socksetup(struct string_list *listen_addr, int listen_port, struct s
}
}
+#ifndef NO_RESTARTABLE_SIGNALS
+
+static void set_sa_restart(struct sigaction *psa, int enable)
+{
+ if (enable)
+ psa->sa_flags |= SA_RESTART;
+ else
+ psa->sa_flags &= ~SA_RESTART;
+ sigaction(SIGCHLD, psa, NULL);
+}
+
+#else
+
+static void set_sa_restart(struct sigaction *psa UNUSED, int enable UNUSED)
+{
+}
+
+#endif
+
static int service_loop(struct socketlist *socklist)
{
struct sigaction sa;
@@ -1136,6 +1155,7 @@ static int service_loop(struct socketlist *socklist)
for (;;) {
check_dead_children();
+ set_sa_restart(&sa, 0);
if (poll(pfd, socklist->nr, -1) < 0) {
if (errno != EINTR) {
logerror("Poll failed, resuming: %s",
@@ -1144,6 +1164,7 @@ static int service_loop(struct socketlist *socklist)
}
continue;
}
+ set_sa_restart(&sa, 1);
for (size_t i = 0; i < socklist->nr; i++) {
if (pfd[i].revents & POLLIN) {
