zdtm: Signalfd testing

It's not in zdtm.sh yet, since kernel patch is not yet
committed. When kernel is updated, the zdtm.sh will be too.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm/live/static/Makefile

@@ -45,6 +45,7 @@ TST_NOFILE	=				\
 		xids00				\
 		file_fown			\
 		eventfs00			\
+		signalfd00			\
 		inotify00			\
 		uptime_grow			\
 		session00			\

test/zdtm/live/static/signalfd00.c

+#define _GNU_SOURCE         /* See feature_test_macros(7) */
+#include <unistd.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/signalfd.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc	= "Check for signalfd without signals";
+const char *test_author	= "Pavel Emelyanov <xemul@parallels.com>";
+
+int main(int argc, char *argv[])
+{
+	int fd, ret;
+	sigset_t mask;
+	siginfo_t info;
+
+	test_init(argc, argv);
+
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGUSR1);
+	fd = signalfd(-1, &mask, SFD_NONBLOCK);
+	if (fd < 0) {
+		fail("Can't create signalfd");
+		exit(1);
+	}
+
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGUSR1);
+	sigaddset(&mask, SIGUSR2);
+	sigprocmask(SIG_BLOCK, &mask, NULL);
+
+	test_daemon();
+	test_waitsig();
+
+	kill(getpid(), SIGUSR2);
+
+	ret = read(fd, &info, sizeof(info));
+	if (ret >= 0) {
+		fail("ghost signal");
+		exit(1);
+	}
+
+	kill(getpid(), SIGUSR1);
+
+	ret = read(fd, &info, sizeof(info));
+	if (ret != sizeof(info)) {
+		fail("no signal");
+		exit(1);
+	}
+
+	if (info.si_signo != SIGUSR1) {
+		fail("wrong signal");
+		exit(1);
+	}
+
+	pass();
+	return 0;
+}