[LTP] [PATCH v2 04/10] syscalls/ioctl_loop02: Add LO_FLAGS_READ_ONLY and LOOP_CHANGE_FD test

[Yang Xu <xuyang2018.jy@cn.fujitsu.com>]

For LOOP_CHANGE_FD, this operation is possible only if the loop device
is read-only and the new backing store is the same size and type as the
old backing store.

Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
---
 runtest/syscalls                              |   1 +
 testcases/kernel/syscalls/ioctl/.gitignore    |   1 +
 .../kernel/syscalls/ioctl/ioctl_loop02.c      | 150 ++++++++++++++++++
 3 files changed, 152 insertions(+)
 create mode 100644 testcases/kernel/syscalls/ioctl/ioctl_loop02.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 8d1ce0c9a..80005227d 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -529,6 +529,7 @@ ioctl07      ioctl07
 ioctl08      ioctl08
 
 ioctl_loop01 ioctl_loop01
+ioctl_loop02 ioctl_loop02
 
 ioctl_ns01 ioctl_ns01
 ioctl_ns02 ioctl_ns02
diff --git a/testcases/kernel/syscalls/ioctl/.gitignore b/testcases/kernel/syscalls/ioctl/.gitignore
index 4cfef2839..534c4ab34 100644
--- a/testcases/kernel/syscalls/ioctl/.gitignore
+++ b/testcases/kernel/syscalls/ioctl/.gitignore
@@ -7,6 +7,7 @@
 /ioctl07
 /ioctl08
 /ioctl_loop01
+/ioctl_loop02
 /ioctl_ns01
 /ioctl_ns02
 /ioctl_ns03
diff --git a/testcases/kernel/syscalls/ioctl/ioctl_loop02.c b/testcases/kernel/syscalls/ioctl/ioctl_loop02.c
new file mode 100644
index 000000000..683171501
--- /dev/null
+++ b/testcases/kernel/syscalls/ioctl/ioctl_loop02.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020 FUJITSU LIMITED. All rights reserved.
+ * Author: Yang Xu <xuyang2018.jy@cn.jujitsu.com>
+ *
+ * This is a basic ioctl test about loopdevice.
+ *
+ * It is designed to test LO_FLAGS_READ_ONLY(similar as losetup -r)
+ * and LOOP_CHANGE_FD.
+ *
+ * For LOOP_CHANGE_FD, this operation is possible only if the loop device
+ * is read-only and the new backing store is the same size and type as the
+ * old backing store.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include "ioctl_loop_support.h"
+#include "lapi/loop.h"
+#include "tst_test.h"
+
+static int file_fd, file_change_fd, file_fd_invalid;
+static char backing_path[1024], backing_file_path[1024], backing_file_change_path[1024];
+static int attach_flag, dev_fd, file_fd;
+static char loop_ro_path[1024], dev_path[1024];
+
+/*
+ * This function is different from tst_attach_dev lib/tst_device.c.
+ * It only opens file_path with O_RDONLY mode before loop_set_fd.
+ * So we can generate LO_FLAGS_READ_ONLY flag.
+ */
+static void attach_device(char *img)
+{
+	dev_fd = SAFE_OPEN(dev_path, O_RDWR);
+	file_fd = SAFE_OPEN(img, O_RDONLY);
+
+	SAFE_IOCTL(dev_fd, LOOP_SET_FD, file_fd);
+
+	SAFE_CLOSE(dev_fd);
+	SAFE_CLOSE(file_fd);
+}
+
+static void verify_ioctl_loop(void)
+{
+	struct loop_info loopinfoget;
+
+	attach_device("test.img");
+	attach_flag = 1;
+
+	check_sys_value(loop_ro_path, 1);
+	check_sys_string(backing_path, backing_file_path);
+
+	dev_fd = SAFE_OPEN(dev_path, O_RDWR);
+	file_change_fd = SAFE_OPEN("test1.img", O_RDWR);
+	file_fd_invalid = SAFE_OPEN("test2.img", O_RDWR);
+
+	memset(&loopinfoget, 0, sizeof(loopinfoget));
+
+	/*
+	 * In drivers/block/loop.c code, set status function doesn't handle
+	 * LO_FLAGS_READ_ONLY flag and ignore it. Only loop_set_fd with readonly
+	 * mode, lo_flags will include LO_FLAGS_READ_ONLY.
+	 */
+	SAFE_IOCTL(dev_fd, LOOP_GET_STATUS, &loopinfoget);
+
+	if (loopinfoget.lo_flags & ~LO_FLAGS_READ_ONLY)
+		tst_res(TFAIL, "lo_flags has unexpected %d flag", loopinfoget.lo_flags);
+	else
+		tst_res(TPASS, "lo_flags only has default LO_FLAGS_READ_ONLY flag");
+
+	TEST(write(dev_fd, "xx", 2));
+	if (TST_RET != -1)
+		tst_res(TFAIL, "write succeed unexpectedly");
+	else
+		tst_res(TPASS | TTERRNO, "Can not write data in RO mode");
+
+	TEST(ioctl(dev_fd, LOOP_CHANGE_FD, file_change_fd));
+	if (TST_RET) {
+		tst_res(TFAIL | TTERRNO, "LOOP_CHANGE_FD failed");
+	} else {
+		tst_res(TPASS, "LOOP_CHANGE_FD succeeded");
+		check_sys_value(loop_ro_path, 1);
+		check_sys_string(backing_path, backing_file_change_path);
+	}
+
+	TEST(ioctl(dev_fd, LOOP_CHANGE_FD, file_fd_invalid));
+	if (TST_RET) {
+		if (TST_ERR == EINVAL)
+			tst_res(TPASS | TTERRNO, "LOOP_CHANGE_FD failed as expected");
+		else
+			tst_res(TFAIL | TTERRNO, "LOOP_CHANGE_FD failed expected EINVAL got");
+	} else {
+		tst_res(TFAIL, "LOOP_CHANGE_FD succeeded");
+	}
+
+	SAFE_CLOSE(dev_fd);
+	SAFE_CLOSE(file_change_fd);
+	SAFE_CLOSE(file_fd_invalid);
+	tst_detach_device(dev_path);
+	attach_flag = 0;
+}
+
+static void setup(void)
+{
+	int dev_num;
+
+	char *tmpdir = tst_get_tmpdir();
+	dev_num = tst_find_free_loopdev(dev_path, sizeof(dev_path));
+	if (dev_num < 0)
+		tst_brk(TBROK, "Failed to find free loop device");
+
+	tst_fill_file("test.img", 0, 1024, 10);
+	tst_fill_file("test1.img", 0, 1024, 10);
+	tst_fill_file("test2.img", 0, 2048, 20);
+
+	sprintf(backing_path, "/sys/block/loop%d/loop/backing_file", dev_num);
+	sprintf(backing_file_path, "%s/test.img", tmpdir);
+	sprintf(backing_file_change_path, "%s/test1.img", tmpdir);
+	sprintf(loop_ro_path, "/sys/block/loop%d/ro", dev_num);
+	if (tmpdir)
+		free(tmpdir);
+}
+
+static void cleanup(void)
+{
+	if (dev_fd > 0)
+		SAFE_CLOSE(dev_fd);
+	if (file_fd > 0)
+		SAFE_CLOSE(file_fd);
+	if (file_change_fd > 0)
+		SAFE_CLOSE(file_change_fd);
+	if (file_fd_invalid > 0)
+		SAFE_CLOSE(file_fd_invalid);
+	if (attach_flag)
+		tst_detach_device(dev_path);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = verify_ioctl_loop,
+	.needs_root = 1,
+	.needs_tmpdir = 1,
+	.needs_drivers = (const char *const []) {
+		"loop",
+		NULL
+	}
+};
-- 
2.23.0