[nft PATCH 1/3] tests/shell: mount all of "/var/run" in "test-wrapper.sh"

[Thomas Haller <thaller@redhat.com>]

After reboot, "/var/run/netns" does not exist before we run the first
`ip netns add` command. Previously, "test-wrapper.sh" would mount a
tmpfs on that directory, but that fails, if the directory doesn't exist.
You will notice this, by deleting /var/run/netns (which only root can
delete or create, and which is wiped on reboot).

Instead, mount all of "/var/run". Then we can also create /var/run/netns
directory.

This means, any other content from /var/run is hidden too. That's
probably desirable, because it means we don't depend on stuff that
happens to be there. If we would require other content in /var/run, then
the test runner needs to be aware of the requirement and ensure it's
present. But best is just to not require anything. It's only iproute2
which insists on /var/run/netns.

Signed-off-by: Thomas Haller <thaller@redhat.com>
---
 tests/shell/helpers/test-wrapper.sh | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/tests/shell/helpers/test-wrapper.sh b/tests/shell/helpers/test-wrapper.sh
index e10360c9b266..13b918f8b8e1 100755
--- a/tests/shell/helpers/test-wrapper.sh
+++ b/tests/shell/helpers/test-wrapper.sh
@@ -23,11 +23,11 @@ START_TIME="$(cut -d ' ' -f1 /proc/uptime)"
 
 export TMPDIR="$NFT_TEST_TESTTMPDIR"
 
-CLEANUP_UMOUNT_RUN_NETNS=n
+CLEANUP_UMOUNT_VAR_RUN=n
 
 cleanup() {
-	if [ "$CLEANUP_UMOUNT_RUN_NETNS" = y ] ; then
-		umount "/var/run/netns" || :
+	if [ "$CLEANUP_UMOUNT_VAR_RUN" = y ] ; then
+		umount "/var/run" &>/dev/null || :
 	fi
 }
 
@@ -38,16 +38,20 @@ printf '%s\n' "$TEST" > "$NFT_TEST_TESTTMPDIR/name"
 read tainted_before < /proc/sys/kernel/tainted
 
 if [ "$NFT_TEST_HAS_UNSHARED_MOUNT" = y ] ; then
-	# We have a private mount namespace. We will mount /run/netns as a tmpfs,
-	# this is useful because `ip netns add` wants to add files there.
+	# We have a private mount namespace. We will mount /var/run/ as a tmpfs.
 	#
-	# When running as rootless, this is necessary to get such tests to
-	# pass.  When running rootful, it's still useful to not touch the
-	# "real" /var/run/netns of the system.
-	mkdir -p /var/run/netns
-	if mount -t tmpfs --make-private "/var/run/netns" ; then
-		CLEANUP_UMOUNT_RUN_NETNS=y
+	# The main purpose is so that we can create /var/run/netns, which is
+	# required for `ip netns add` to work.  When running as rootless, this
+	# is necessary to get such tests to pass. When running rootful, it's
+	# still useful to not touch the "real" /var/run/netns of the system.
+	#
+	# Note that this also hides everything that might reside in /var/run.
+	# That is desirable, as tests should not depend on content there (or if
+	# they do, we need to explicitly handle it as appropriate).
+	if mount -t tmpfs --make-private "/var/run" ; then
+		CLEANUP_UMOUNT_VAR_RUN=y
 	fi
+	mkdir -p /var/run/netns
 fi
 
 TEST_TAGS_PARSED=0
-- 
2.41.0