1 files changed, 96 insertions, 0 deletions
diff --git a/src/home/homework-mount.c b/src/home/homework-mount.c
new file mode 100644
index 0000000..5e73768
--- /dev/null
+++ b/src/home/homework-mount.c
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sched.h>
+#include <sys/mount.h>
+
+#include "alloc-util.h"
+#include "homework-mount.h"
+#include "mkdir.h"
+#include "mount-util.h"
+#include "path-util.h"
+#include "string-util.h"
+
+static const char *mount_options_for_fstype(const char *fstype) {
+        if (streq(fstype, "ext4"))
+                return "noquota,user_xattr";
+        if (streq(fstype, "xfs"))
+                return "noquota";
+        if (streq(fstype, "btrfs"))
+                return "noacl";
+        return NULL;
+}
+
+int home_mount_node(const char *node, const char *fstype, bool discard, unsigned long flags) {
+        _cleanup_free_ char *joined = NULL;
+        const char *options, *discard_option;
+        int r;
+
+        options = mount_options_for_fstype(fstype);
+
+        discard_option = discard ? "discard" : "nodiscard";
+
+        if (options) {
+                joined = strjoin(options, ",", discard_option);
+                if (!joined)
+                        return log_oom();
+
+                options = joined;
+        } else
+                options = discard_option;
+
+        r = mount_nofollow_verbose(LOG_ERR, node, "/run/systemd/user-home-mount", fstype, flags|MS_RELATIME, strempty(options));
+        if (r < 0)
+                return r;
+
+        log_info("Mounting file system completed.");
+        return 0;
+}
+
+int home_unshare_and_mount(const char *node, const char *fstype, bool discard, unsigned long flags) {
+        int r;
+
+        if (unshare(CLONE_NEWNS) < 0)
+                return log_error_errno(errno, "Couldn't unshare file system namespace: %m");
+
+        r = mount_nofollow_verbose(LOG_ERR, "/run", "/run", NULL, MS_SLAVE|MS_REC, NULL); /* Mark /run as MS_SLAVE in our new namespace */
+        if (r < 0)
+                return r;
+
+        (void) mkdir_p("/run/systemd/user-home-mount", 0700);
+
+        if (node)
+                return home_mount_node(node, fstype, discard, flags);
+
+        return 0;
+}
+
+int home_move_mount(const char *user_name_and_realm, const char *target) {
+        _cleanup_free_ char *subdir = NULL;
+        const char *d;
+        int r;
+
+        assert(user_name_and_realm);
+        assert(target);
+
+        if (user_name_and_realm) {
+                subdir = path_join("/run/systemd/user-home-mount/", user_name_and_realm);
+                if (!subdir)
+                        return log_oom();
+
+                d = subdir;
+        } else
+                d = "/run/systemd/user-home-mount/";
+
+        (void) mkdir_p(target, 0700);
+
+        r = mount_nofollow_verbose(LOG_ERR, d, target, NULL, MS_BIND, NULL);
+        if (r < 0)
+                return r;
+
+        r = umount_verbose(LOG_ERR, "/run/systemd/user-home-mount", UMOUNT_NOFOLLOW);
+        if (r < 0)
+                return r;
+
+        log_info("Moving to final mount point %s completed.", target);
+        return 0;
+}