1 files changed, 71 insertions, 0 deletions
diff --git a/src/basic/mountpoint-util.h b/src/basic/mountpoint-util.h
new file mode 100644
index 0000000..499403a
--- /dev/null
+++ b/src/basic/mountpoint-util.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <fcntl.h>
+#include <stdbool.h>
+#include <sys/types.h>
+
+/* The limit used for /dev itself. 4MB should be enough since device nodes and symlinks don't
+ * consume any space and udev isn't supposed to create regular file either. There's no limit on the
+ * max number of inodes since such limit is hard to guess especially on large storage array
+ * systems. */
+#define TMPFS_LIMITS_DEV             ",size=4m"
+
+/* The limit used for /dev in private namespaces. 4MB for contents of regular files. The number of
+ * inodes should be relatively low in private namespaces but for now use a 64k limit. */
+#define TMPFS_LIMITS_PRIVATE_DEV     ",size=4m,nr_inodes=64k"
+
+/* Very little, if any use expected */
+#define TMPFS_LIMITS_EMPTY_OR_ALMOST ",size=4m,nr_inodes=1k"
+#define TMPFS_LIMITS_SYS             TMPFS_LIMITS_EMPTY_OR_ALMOST
+#define TMPFS_LIMITS_SYS_FS_CGROUP   TMPFS_LIMITS_EMPTY_OR_ALMOST
+
+/* On an extremely small device with only 256MB of RAM, 20% of RAM should be enough for the re-execution of
+ * PID1 because 16MB of free space is required. */
+#define TMPFS_LIMITS_RUN             ",size=20%,nr_inodes=800k"
+
+/* The limit used for various nested tmpfs mounts, in particular for guests started by systemd-nspawn.
+ * 10% of RAM (using 16GB of RAM as a baseline) translates to 400k inodes (assuming 4k each) and 25%
+ * translates to 1M inodes.
+ * (On the host, /tmp is configured through a .mount unit file.) */
+#define NESTED_TMPFS_LIMITS          ",size=10%,nr_inodes=400k"
+
+/* More space for volatile root and /var */
+#define TMPFS_LIMITS_VAR             ",size=25%,nr_inodes=1m"
+#define TMPFS_LIMITS_ROOTFS          TMPFS_LIMITS_VAR
+#define TMPFS_LIMITS_VOLATILE_STATE  TMPFS_LIMITS_VAR
+
+int name_to_handle_at_loop(int fd, const char *path, struct file_handle **ret_handle, int *ret_mnt_id, int flags);
+
+int path_get_mnt_id_at_fallback(int dir_fd, const char *path, int *ret);
+int path_get_mnt_id_at(int dir_fd, const char *path, int *ret);
+static inline int path_get_mnt_id(const char *path, int *ret) {
+        return path_get_mnt_id_at(AT_FDCWD, path, ret);
+}
+
+int fd_is_mount_point(int fd, const char *filename, int flags);
+int path_is_mount_point(const char *path, const char *root, int flags);
+
+bool fstype_is_network(const char *fstype);
+bool fstype_needs_quota(const char *fstype);
+bool fstype_is_api_vfs(const char *fstype);
+bool fstype_is_blockdev_backed(const char *fstype);
+bool fstype_is_ro(const char *fsype);
+bool fstype_can_discard(const char *fstype);
+bool fstype_can_uid_gid(const char *fstype);
+bool fstype_can_norecovery(const char *fstype);
+bool fstype_can_umask(const char *fstype);
+
+int dev_is_devtmpfs(void);
+
+int mount_fd(const char *source, int target_fd, const char *filesystemtype, unsigned long mountflags, const void *data);
+int mount_nofollow(const char *source, const char *target, const char *filesystemtype, unsigned long mountflags, const void *data);
+
+const char *mount_propagation_flag_to_string(unsigned long flags);
+int mount_propagation_flag_from_string(const char *name, unsigned long *ret);
+bool mount_propagation_flag_is_valid(unsigned long flag);
+
+bool mount_new_api_supported(void);
+unsigned long ms_nosymfollow_supported(void);
+
+int mount_option_supported(const char *fstype, const char *key, const char *value);