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authorAndrey Ulanov <aulanov@gmail.com>2016-12-12 17:38:18 -0800
committerLennart Poettering <lennart@poettering.net>2016-12-13 02:38:18 +0100
commit6916b164642d8bb4938878f4284f8ee5ccf3efd6 (patch)
tree93bd487bea06d59307608ad2361dcbe8a266f58c /src/nspawn
parentbbc5d5286b39e9648186f7e05e6cc89aa295ee7a (diff)
nspawn: when getting SIGCHLD make sure it's from the first child (#4855)
When getting SIGCHLD we should not assume that it was the first child forked from system-nspawn that has died as it may also be coming from an orphan process. This change adds a signal handler that ignores SIGCHLD unless it came from the first containerized child - the real child. Before this change the problem can be reproduced as follows: $ sudo systemd-nspawn --directory=/container-root --share-system Press ^] three times within 1s to kill container. [root@andreyu-coreos ~]# { true & } & [1] 22201 [root@andreyu-coreos ~]# Container root-fedora-latest terminated by signal KILL
Diffstat (limited to 'src/nspawn')
-rw-r--r--src/nspawn/nspawn.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index d701f2158d..080bd7c31e 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -38,6 +38,7 @@
#include <sys/personality.h>
#include <sys/prctl.h>
#include <sys/types.h>
+#include <sys/wait.h>
#include <unistd.h>
#include "sd-daemon.h"
@@ -1933,6 +1934,26 @@ static int on_orderly_shutdown(sd_event_source *s, const struct signalfd_siginfo
return 0;
}
+static int on_sigchld(sd_event_source *s, const struct signalfd_siginfo *ssi, void *userdata) {
+ for (;;) {
+ siginfo_t si = {};
+ if (waitid(P_ALL, 0, &si, WNOHANG|WNOWAIT|WEXITED) < 0)
+ return log_error_errno(errno, "Failed to waitid(): %m");
+ if (si.si_pid == 0) /* No pending children. */
+ break;
+ if (si.si_pid == PTR_TO_PID(userdata)) {
+ /* The main process we care for has exited. Return from
+ * signal handler but leave the zombie. */
+ sd_event_exit(sd_event_source_get_event(s), 0);
+ break;
+ }
+ /* Reap all other children. */
+ (void) waitid(P_PID, si.si_pid, &si, WNOHANG|WEXITED);
+ }
+
+ return 0;
+}
+
static int determine_names(void) {
int r;
@@ -3361,8 +3382,8 @@ static int run(int master,
sd_event_add_signal(event, NULL, SIGTERM, NULL, NULL);
}
- /* simply exit on sigchld */
- sd_event_add_signal(event, NULL, SIGCHLD, NULL, NULL);
+ /* Exit when the child exits */
+ sd_event_add_signal(event, NULL, SIGCHLD, on_sigchld, PID_TO_PTR(*pid));
if (arg_expose_ports) {
r = expose_port_watch_rtnl(event, rtnl_socket_pair[0], on_address_change, exposed, &rtnl);