core,nspawn: unify code that moves the root dir

2 files changed, 20 insertions, 0 deletions

diff --git a/src/shared/util.c b/src/shared/util.c
index e18645f8f1..c3b08bbc43 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -6229,3 +6229,21 @@ int parse_mode(const char *s, mode_t *ret) {
         *ret = (mode_t) l;
         return 0;
 }
+
+int mount_move_root(const char *path) {
+        assert(path);
+
+        if (chdir(path) < 0)
+                return -errno;
+
+        if (mount(path, "/", NULL, MS_MOVE, NULL) < 0)
+                return -errno;
+
+        if (chroot(".") < 0)
+                return -errno;
+
+        if (chdir("/") < 0)
+                return -errno;
+
+        return 0;
+}
diff --git a/src/shared/util.h b/src/shared/util.h
index 0e806cf1a1..f0382f0d68 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -906,3 +906,5 @@ int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char
 char *shell_maybe_quote(const char *s);
 
 int parse_mode(const char *s, mode_t *ret);
+
+int mount_move_root(const char *path);