[LTP] [PATCH v1] fsconfig04.c: Use FSCONFIG_SET_FD set overlayfs

[Wei Gao]

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                              |   1 +
 testcases/kernel/syscalls/fsconfig/.gitignore |   1 +
 .../kernel/syscalls/fsconfig/fsconfig04.c     | 132 ++++++++++++++++++
 3 files changed, 134 insertions(+)
 create mode 100644 testcases/kernel/syscalls/fsconfig/fsconfig04.c

diff --git a/runtest/syscalls b/runtest/syscalls
index e369536ea..658ab24c4 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -410,6 +410,7 @@ fremovexattr02 fremovexattr02
 fsconfig01 fsconfig01
 fsconfig02 fsconfig02
 fsconfig03 fsconfig03
+fsconfig04 fsconfig04
 
 fsmount01 fsmount01
 fsmount02 fsmount02
diff --git a/testcases/kernel/syscalls/fsconfig/.gitignore b/testcases/kernel/syscalls/fsconfig/.gitignore
index cfedae5f7..bd3754c34 100644
--- a/testcases/kernel/syscalls/fsconfig/.gitignore
+++ b/testcases/kernel/syscalls/fsconfig/.gitignore
@@ -1,3 +1,4 @@
 /fsconfig01
 /fsconfig02
 /fsconfig03
+/fsconfig04
diff --git a/testcases/kernel/syscalls/fsconfig/fsconfig04.c b/testcases/kernel/syscalls/fsconfig/fsconfig04.c
new file mode 100644
index 000000000..c77dc9e3a
--- /dev/null
+++ b/testcases/kernel/syscalls/fsconfig/fsconfig04.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2025 Wei Gao <wegao@suse.com>
+ *
+ * Basic fsconfig() test include use FSCONFIG_SET_FD set overlayfs
+ * Refer to selftests/filesystems/overlayfs/set_layers_via_fds.c
+ */
+
+#include "tst_test.h"
+#include "lapi/fsmount.h"
+#include "tst_safe_file_at.h"
+#include "tst_safe_stdio.h"
+
+#define MNTPOINT	"mntpoint"
+#define OVERLAYMNT	"set_layers_via_fds"
+
+static int fd, fd_context, fd_overlay;
+
+static void cleanup(void)
+{
+	if (fd != -1)
+		SAFE_CLOSE(fd);
+
+	if (fd_context != -1)
+		SAFE_CLOSE(fd_context);
+
+	if (fd_overlay != -1)
+		SAFE_CLOSE(fd_overlay);
+}
+
+static void run(void)
+{
+	int fsmfd;
+
+	fd = TST_EXP_FD(fsopen(tst_device->fs_type, 0));
+
+	TST_EXP_PASS(fsconfig(fd, FSCONFIG_SET_STRING, "source", tst_device->dev, 0));
+
+	TST_EXP_PASS(fsconfig(fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0));
+
+	fsmfd = TST_EXP_FD(fsmount(fd, 0, 0));
+
+	TST_EXP_PASS(mkdirat(fsmfd, "w", 0755));
+	TST_EXP_PASS(mkdirat(fsmfd, "u", 0755));
+	TST_EXP_PASS(mkdirat(fsmfd, "l1", 0755));
+	TST_EXP_PASS(mkdirat(fsmfd, "l2", 0755));
+
+	int layer_fds[] = { [0 ... 3] = -EBADF };
+
+	layer_fds[0] = SAFE_OPENAT(fsmfd, "w", O_DIRECTORY);
+	layer_fds[1] = SAFE_OPENAT(fsmfd, "u", O_DIRECTORY);
+	layer_fds[2] = SAFE_OPENAT(fsmfd, "l1", O_DIRECTORY);
+	layer_fds[3] = SAFE_OPENAT(fsmfd, "l2", O_DIRECTORY);
+
+	TST_EXP_PASS(move_mount(fsmfd, "", AT_FDCWD, MNTPOINT,
+			MOVE_MOUNT_F_EMPTY_PATH));
+
+	SAFE_CLOSE(fsmfd);
+
+	fd_context = TST_EXP_FD(fsopen("overlay", 0));
+
+	TST_EXP_PASS(fsconfig(fd_context, FSCONFIG_SET_FD, "workdir", NULL, layer_fds[0]));
+	TST_EXP_PASS(fsconfig(fd_context, FSCONFIG_SET_FD, "upperdir", NULL, layer_fds[1]));
+	TST_EXP_PASS(fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, layer_fds[2]));
+	TST_EXP_PASS(fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, layer_fds[3]));
+
+	TST_EXP_PASS(fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0));
+
+	SAFE_MKDIR(OVERLAYMNT, 0555);
+
+	fd_overlay = TST_EXP_FD(fsmount(fd_context, 0, 0));
+	SAFE_CLOSE(fd_context);
+
+	TST_EXP_PASS(move_mount(fd_overlay, "", AT_FDCWD, OVERLAYMNT,
+			MOVE_MOUNT_F_EMPTY_PATH));
+
+	char line[PATH_MAX];
+	FILE *file;
+	int ret = 0;
+	char workdir[PATH_MAX], upperdir[PATH_MAX], lowerdir1[PATH_MAX], lowerdir2[PATH_MAX];
+	char *tmpdir_path = tst_tmpdir_path();
+
+	sprintf(workdir, "workdir=%s/%s/w", tmpdir_path, MNTPOINT);
+	sprintf(upperdir, "upperdir=%s/%s/u", tmpdir_path, MNTPOINT);
+	sprintf(lowerdir1, "lowerdir+=%s/%s/l1", tmpdir_path, MNTPOINT);
+	sprintf(lowerdir2, "lowerdir+=%s/%s/l2", tmpdir_path, MNTPOINT);
+
+	file = SAFE_FOPEN("/proc/mounts", "r");
+	while (fgets(line, sizeof(line), file)) {
+		if (strstr(line, workdir) && strstr(line, upperdir)
+				&& strstr(line, lowerdir1) && strstr(line, lowerdir2)) {
+			ret = 1;
+			break;
+		}
+	}
+
+	if (ret == 1)
+		tst_res(TPASS, "overlay mount check pass");
+	else
+		tst_res(TFAIL, "overlay mount check failed");
+
+	TST_EXP_PASS_SILENT(system("ls -l"));
+
+	char rmcmd[PATH_MAX];
+
+	sprintf(rmcmd, "rm -r ./%s/*", MNTPOINT);
+	TST_EXP_PASS_SILENT(system(rmcmd));
+
+	SAFE_CLOSE(fd_overlay);
+	SAFE_UMOUNT(OVERLAYMNT);
+	SAFE_RMDIR(OVERLAYMNT);
+
+	SAFE_CLOSE(fd);
+
+	for (int i = 0; i < 4; i++)
+		SAFE_CLOSE(layer_fds[i]);
+
+	if (tst_is_mounted_at_tmpdir(MNTPOINT)) {
+		SAFE_UMOUNT(MNTPOINT);
+	}
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.setup = fsopen_supported_by_kernel,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.format_device = 1,
+	.mntpoint = MNTPOINT,
+	.all_filesystems = 1,
+	.skip_filesystems = (const char *const []){"ntfs", "vfat", "exfat", NULL},
+};
-- 
2.49.0