From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Sun, 25 Dec 2016 11:26:17 +0000 (+0100)
Subject: tests: skip unpriv tests on broken overlay module
X-Git-Tag: lxc-1.0.10~27
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e8a89cf398f47bfbdc186fbeb1c9c82917dd6044;p=thirdparty%2Flxc.git

tests: skip unpriv tests on broken overlay module

This mainly affects Trusty. The 3.13 kernel has a broken overlay module which
does not handle symlinks correctly. This is a problem for containers that use
an overlay based rootfs since safe_mount() uses /proc/<pid>/fd/<fd-number> in
its calls to mount().

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/tests/lxc-test-unpriv b/src/tests/lxc-test-unpriv
index 93c91a9f4..54ddc6637 100755
--- a/src/tests/lxc-test-unpriv
+++ b/src/tests/lxc-test-unpriv
@@ -27,6 +27,41 @@ if [ $(id -u) -ne 0 ]; then
 	echo "ERROR: Must run as root."
 	exit 1
 fi
+
+# Test if we're using an overlayfs module that handles symlinks correctly. If
+# not, we skip these tests since overlay clones will not work correctly.
+if modprobe -q overlayfs; then
+        TMPDIR=$(mktemp -d)
+
+        MOUNTDIR="${TMPDIR}/ovl_symlink_test"
+
+        mkdir ${MOUNTDIR}
+
+        mount -t tmpfs none ${MOUNTDIR}
+
+        mkdir "${MOUNTDIR}/lowerdir" "${MOUNTDIR}/upperdir" "${MOUNTDIR}/overlayfs"
+        mount -t overlayfs -o lowerdir="${MOUNTDIR}/lowerdir",upperdir="${MOUNTDIR}/upperdir" none "${MOUNTDIR}/overlayfs"
+
+        CORRECT_LINK_TARGET="${MOUNTDIR}/overlayfs/dummy_file"
+        exec 9> "${CORRECT_LINK_TARGET}"
+
+        DETECTED_LINK_TARGET=$(readlink -q /proc/$$/fd/9)
+
+        # cleanup
+        exec 9>&-
+
+        umount "${MOUNTDIR}/overlayfs"
+        umount ${MOUNTDIR}
+
+        rmdir ${MOUNTDIR}
+
+        # This overlay module does not correctly handle symlinks, so skip the
+        # tests.
+        if [ "${DETECTED_LINK_TARGET}" != "${CORRECT_LINK_TARGET}" ]; then
+                exit 0
+        fi
+fi
+
 which newuidmap >/dev/null 2>&1 || { echo "'newuidmap' command is missing" >&2; exit 1; }
 
 DONE=0