unshare: don't try to reset the disposition of SIGKILL

If the child process is killed with SIGKILL, don't attempt to reset the
disposition of SIGKILL (which can't be caught or ignored anyway) before
self-signalling. This caused a misleading 'sigprocmask unblock failed'
error instead of dying with the same SIGKILL status as the child.

Fixes: https://github.com/util-linux/util-linux/issues/2614
Signed-off-by: Chris Webb <chris@arachsys.com>

diff --git a/sys-utils/unshare.c b/sys-utils/unshare.c
index 6222c1421c634c35adbcd9fe0a0f03d940bfb08d..d46985bf1d41d75df17c289d0a33c5ad1d7f4aa7 100644 (file)
--- a/sys-utils/unshare.c
+++ b/sys-utils/unshare.c
@@ -994,8 +994,10 @@ int main(int argc, char *argv[])
 
                        int termsig = WTERMSIG(status);
 
-                       if (signal(termsig, SIG_DFL) == SIG_ERR ||
-                               sigemptyset(&sigset) != 0 ||
+                       if (termsig != SIGKILL && signal(termsig, SIG_DFL) == SIG_ERR)
+                               err(EXIT_FAILURE,
+                                       _("signal handler reset failed"));
+                       if (sigemptyset(&sigset) != 0 ||
                                sigaddset(&sigset, termsig) != 0 ||
                                sigprocmask(SIG_UNBLOCK, &sigset, NULL) != 0)
                                err(EXIT_FAILURE,