[WIP] Tests for podman image scp (the sudo form)

Start inching our way back to having tests for the sudo form
of podman image scp. Basically, copy an image to another user
and then back, using a pseudorandom name. Confirm that the
image makes it to the remote end, and that when we copy it
back, the original image digest is preserved.

When scp'ing as root, we identify the destination rootless
user account via the $PODMAN_ROOTLESS_USER envariable. Setting
this and creating the account is left as an exercise for the
CI framework (be it github, or Fedora/CentOS/RHEL gating, or
other).

Also: amend hack/bats to set and relay $PODMAN_ROOTLESS_USER,
so developers can test locally.

Also: remove what I'm 99% sure is a debugging printf.

Signed-off-by: Ed Santiago <santiago@redhat.com>

hack/bats

@@ -98,6 +98,9 @@ if [[ -z "$CONTAINERS_HELPER_BINARY_DIR" ]]; then
     export CONTAINERS_HELPER_BINARY_DIR=$(pwd)/bin
 fi
 
+# Used in 120-load test to identify rootless destination for podman image scp
+export PODMAN_ROOTLESS_USER=$(id -un)
+
 # Root
 if [ -z "$ROOTLESS_ONLY" ]; then
     echo "# bats ${bats_filter[@]} $TESTS"
@@ -105,6 +108,7 @@ if [ -z "$ROOTLESS_ONLY" ]; then
             --preserve-env=PODMAN_TEST_DEBUG \
             --preserve-env=OCI_RUNTIME \
             --preserve-env=CONTAINERS_HELPER_BINARY_DIR \
+            --preserve-env=PODMAN_ROOTLESS_USER \
             bats "${bats_opts[@]}" "${bats_filter[@]}" $TESTS
     rc=$?
 fi

test/system/120-load.bats

@@ -80,26 +80,94 @@ verify_iid_and_name() {
 
 @test "podman image scp transfer" {
     skip_if_remote "only applicable under local podman"
-
-    skip "FIXME FIXME FIXME: this needs a big rewrite"
-
-    get_iid_and_name
-    if is_rootless; then
-        whoami=$(id -un)
-        # FIXME: first, test that we can sudo. If we can't, skip.
-        # FIXME: test 'scp $IMAGE root@localhost::'
-        # FIXME: then test the rest
-        # FIXME: check output
-        run_podman image scp $whoami@localhost::$iid root@localhost::
-        is "$output" "Loaded image.*: $iid" "...."
-
-        # FIXME: "-q" is a NOP
-        run_podman image scp -q $whoami@localhost::$iid root@localhost::
-    else
-        # root
-        # FIXME: identify a rootless user. DO NOT CREATE ONE.
-        run_podman image scp root@localhost::$iid 1000:1000@localhost::
+    if is_ubuntu; then
+        skip "I don't have time to deal with this"
     fi
+
+    # The testing is the same whether we're root or rootless; all that
+    # differs is the destination (not-me) username.
+    if is_rootless; then
+        # Simple: push to root.
+        whoami=$(id -un)
+        notme=root
+        _sudo() { command sudo -n "$@"; }
+    else
+        # Harder: our CI infrastructure needs to define this & set up the acct
+        whoami=root
+        notme=${PODMAN_ROOTLESS_USER}
+        if [[ -z "$notme" ]]; then
+            skip "To run this test, set PODMAN_ROOTLESS_USER to a safe username"
+        fi
+        _sudo() { command sudo -n -u "$notme" "$@"; }
+    fi
+
+    # If we can't sudo, we can't test.
+    _sudo true || skip "cannot sudo to $notme"
+
+    # FIXME FIXME FIXME: it'd be reeeeeeally nice if we could pass --root
+    #                    to the non-self user, hence avoid vandalizing
+    #                    their storage.
+
+    # Preserve digest of original image; we will compare against it later
+    run_podman image inspect --format '{{.Digest}}' $IMAGE
+    src_digest=$output
+
+    # image name that is not likely to exist in the destination
+    newname=foo.bar/nonesuch/c_$(random_string 10 | tr A-Z a-z):mytag
+    run_podman tag $IMAGE $newname
+
+    # Copy it there.
+    # FIXME: the first '.*' in the expect string below is unfortunate; it's
+    #        a workaround for Ubuntu which gripes:
+    #        "warning.*defaulting to su since machinectl is not available"
+    #        Reexamine this once #12829 is fixed
+    run_podman image scp $newname ${notme}@localhost::
+    is "$output" ".*Copying blob .*Copying config.*Writing manifest.*Storing signatures"
+
+    # confirm that image was copied. FIXME: also try $PODMAN image inspect?
+    _sudo $PODMAN image exists $newname
+
+    # Copy it back, this time using -q
+    run_podman untag $IMAGE $newname
+    run_podman image scp -q ${notme}@localhost::$newname
+
+    expect="Loaded image(s): $newname"
+    # FIXME FIXME FIXME: ubuntu has no machinectl, emits useless warning message instead
+    if ! is_rootless; then
+        # FIXME: root on fedora uses machinectl, which emits useless \n and \r (#12829)
+        NL=$'\n'
+        CR=$'\r'
+        expect="$NL$expect$CR"
+    fi
+    is "$output" "$expect" "-q silences output"
+
+    # Confirm that we have it, and that its digest matches our original
+    run_podman image inspect --format '{{.Digest}}' $newname
+    is "$output" "$src_digest" "Digest of re-fetched image matches original"
+
+    # Clean up
+    _sudo $PODMAN image rm $newname
+    run_podman untag $IMAGE $newname
+
+    # Negative test for nonexistent image.
+    # FIXME FIXME: cannot test on root, because it uses machinectl (#12829)
+    if is_rootless; then
+        # FIXME: error message is 2 lines, the 2nd being "exit status 125".
+        # FIXME: is that fixable, or do we have to live with it?
+        nope="nope.nope/nonesuch:notag"
+        run_podman 125 image scp ${notme}@localhost::$nope
+        is "$output" "Error: $nope: image not known.*" "Pulling nonexistent image"
+
+        run_podman 125 image scp $nope ${notme}@localhost::
+        is "$output" "Error: $nope: image not known.*" "Pushing nonexistent image"
+    fi
+
+    # Negative test for copying to a different name
+    run_podman 125 image scp $IMAGE ${notme}@localhost::newname:newtag
+    is "$output" "Error: cannot specify an image rename: invalid argument" \
+       "Pushing with a different name: not allowed"
+
+    # FIXME: any point in copying by image ID? What else should we test?
 }