signalfd: Add negative tests

Add negative cases for signalfd(), when errno is EBADF or EINVAL

Signed-off-by: Ma Xinjian <maxj.fnst@fujitsu.com>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>

runtest/syscalls

@@ -1514,6 +1514,7 @@ signal05 signal05
 signal06 signal06
 
 signalfd01 signalfd01
+signalfd02 signalfd02
 
 signalfd4_01 signalfd4_01
 signalfd4_02 signalfd4_02

testcases/kernel/syscalls/signalfd/.gitignore

@@ -1 +1,2 @@
 /signalfd01
+/signalfd02

testcases/kernel/syscalls/signalfd/signalfd02.c

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2024 FUJITSU LIMITED. All Rights Reserved.
+ * Author: Ma Xinjian <maxj.fnst@fujitsu.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Verify that signalfd(2) fails with:
+ *
+ * - EBADF when fd is invalid
+ * - EINVAL when fd is not a valid signalfd file descriptor
+ * - EINVAL when flags are invalid
+ */
+
+#include <sys/signalfd.h>
+#include "tst_test.h"
+
+#define SIGNAL_FILE "signal_file"
+
+static int fd_ebadf = -2;
+static int fd_einval1;
+static int fd_einval2 = -1;
+
+static sigset_t *mask;
+
+static struct test_case_t {
+	int *fd;
+	int flags;
+	int expected_errno;
+	char *desc;
+} tcases[] = {
+	{&fd_ebadf, 0, EBADF, "fd is invalid"},
+	{&fd_einval1, 0, EINVAL,
+		"fd is not a valid signalfd file descriptor"},
+	{&fd_einval2, -1, EINVAL, "flags are invalid"},
+};
+
+static void setup(void)
+{
+	SAFE_SIGEMPTYSET(mask);
+	SAFE_SIGADDSET(mask, SIGUSR1);
+	SAFE_SIGPROCMASK(SIG_BLOCK, mask, NULL);
+
+	fd_einval1 = SAFE_OPEN(SIGNAL_FILE, O_CREAT, 0777);
+}
+
+static void cleanup(void)
+{
+	if (fd_einval1 > 0)
+		SAFE_CLOSE(fd_einval1);
+}
+
+static void verify_signalfd(unsigned int i)
+{
+	struct test_case_t *tc = &tcases[i];
+
+	TST_EXP_FAIL2(signalfd(*(tc->fd), mask, tc->flags),
+		tc->expected_errno, "%s", tc->desc);
+}
+
+static struct tst_test test = {
+	.tcnt = ARRAY_SIZE(tcases),
+	.test = verify_signalfd,
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_tmpdir = 1,
+	.bufs = (struct tst_buffers []) {
+		{&mask, .size = sizeof(sigset_t)},
+		{}
+	}
+};