fix signal sending in lxc.init

The problem here is that these two clauses were ordered backwards: we first
check if the signal came from not the init pid, and if it did, then we give
a notice and return. The comment notes that this is intended to protect
against SIGCHLD, but we don't in fact know if the signal is a SIGCHLD yet,
because that's tested in the next hunk.

The symptom is that if I e.g. send SIGTERM from the outside world to the
container init, it ignores it and gives this notice. If we re-order these
clauses, it forwards non SIGCHLD signals, and ignores SIGCHLD signals from
things that aren't the real container process.

Signed-off-by: Tycho Andersen <tycho@tycho.ws>

diff --git a/src/lxc/start.c b/src/lxc/start.c
index f66f50a7b8fe888773a00f7f14d30a19c710bf8b..d7f079979e8c21b02e66a7d6a9fe42c2936db0c4 100644 (file)
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -380,6 +380,12 @@ static int signal_handler(int fd, uint32_t events, void *data,
                return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
        }
 
+       if (siginfo.ssi_signo != SIGCHLD) {
+               kill(hdlr->pid, siginfo.ssi_signo);
+               INFO("Forwarded signal %d to pid %d", siginfo.ssi_signo, hdlr->pid);
+               return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
+       }
+
        /* More robustness, protect ourself from a SIGCHLD sent
         * by a process different from the container init.
         */
@@ -389,12 +395,6 @@ static int signal_handler(int fd, uint32_t events, void *data,
                return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
        }
 
-       if (siginfo.ssi_signo != SIGCHLD) {
-               kill(hdlr->pid, siginfo.ssi_signo);
-               INFO("Forwarded signal %d to pid %d", siginfo.ssi_signo, hdlr->pid);
-               return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
-       }
-
        if (siginfo.ssi_code == CLD_STOPPED) {
                INFO("Container init process was stopped");
                return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;