From: Daan De Meyer <daan.j.demeyer@gmail.com>
Date: Mon, 15 Dec 2025 20:24:15 +0000 (+0100)
Subject: sandbox: Add better error reporting for overlayfs
X-Git-Tag: v26~7^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f2338b9a86cf61ab3d2c393ad49afecd5da8fb72;p=thirdparty%2Fmkosi.git

sandbox: Add better error reporting for overlayfs

Let's do some basic checks up front so we catch
trivial errors ourselves instead of having to
debug obscure errors we get back from the kernel
when calling mount().
---

diff --git a/mkosi/sandbox.py b/mkosi/sandbox.py
index bb10902ae..22829b90d 100755
--- a/mkosi/sandbox.py
+++ b/mkosi/sandbox.py
@@ -946,6 +946,16 @@ class OverlayOperation(FSOperation):
         workdir = chase(oldroot, self.workdir) if self.workdir else None
         dst = chase(newroot, self.dst)
 
+        for p in lowerdirs:
+            if not os.path.exists(p):
+                oserror("mount", p, ENOENT)
+
+        if upperdir and upperdir != "tmpfs" and upperdir != dst and not os.path.exists(upperdir):
+            oserror("mount", upperdir, ENOENT)
+
+        if workdir and not os.path.exists(workdir):
+            oserror("mount", workdir, ENOENT)
+
         with umask(~0o755):
             os.makedirs(os.path.dirname(dst), exist_ok=True)