nss: block various signals while running NSS lookups

Let's make sure our poll() calls don't get interrupted where they shouldn't (SIGALRM, ...), but allow them to be
interrupted where they should (SIGINT, ...).

Fixes #1965

diff --git a/src/test/test-signal-util.c b/src/test/test-signal-util.c
new file mode 100644 (file)
index 0000000..82acdd3
--- /dev/null
+++ b/src/test/test-signal-util.c
@@ -0,0 +1,49 @@
+/***
+  This file is part of elogind.
+
+  Copyright 2016 Lennart Poettering
+
+  elogind is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  elogind is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with elogind; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "signal-util.h"
+
+static void test_block_signals(void) {
+        sigset_t ss;
+
+        assert_se(sigprocmask(0, NULL, &ss) >= 0);
+
+        assert_se(sigismember(&ss, SIGUSR1) == 0);
+        assert_se(sigismember(&ss, SIGALRM) == 0);
+        assert_se(sigismember(&ss, SIGVTALRM) == 0);
+
+        {
+                BLOCK_SIGNALS(SIGUSR1, SIGVTALRM);
+
+                assert_se(sigprocmask(0, NULL, &ss) >= 0);
+                assert_se(sigismember(&ss, SIGUSR1) == 1);
+                assert_se(sigismember(&ss, SIGALRM) == 0);
+                assert_se(sigismember(&ss, SIGVTALRM) == 1);
+
+        }
+
+        assert_se(sigprocmask(0, NULL, &ss) >= 0);
+        assert_se(sigismember(&ss, SIGUSR1) == 0);
+        assert_se(sigismember(&ss, SIGALRM) == 0);
+        assert_se(sigismember(&ss, SIGVTALRM) == 0);
+}
+
+int main(int argc, char *argv[]) {
+        test_block_signals();
+}