Command-line input validation: reject unused args

Several podman commands accept no subcommands. Some
of those were not actually checking, though, which
could lead to user confusion. Added validation where
missing; and, refactored to minimize duplication.

(Side note: I decided against using cobra.NoArgs
because its error message, "unknown command",
misleadingly implies that there are known ones).

Also added validation to varlink

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

1 files changed, 8 insertions, 0 deletions

diff --git a/cmd/podman/common.go b/cmd/podman/common.go
index e297f3921..1fb06cf91 100644
--- a/cmd/podman/common.go
+++ b/cmd/podman/common.go
@@ -59,6 +59,14 @@ func checkAllAndLatest(c *cobra.Command, args []string, ignoreArgLen bool) error
 	return nil
 }
 
+// noSubArgs checks that there are no further positional parameters
+func noSubArgs(c *cobra.Command, args []string) error {
+	if len(args) > 0 {
+		return errors.Errorf("`%s` takes no arguments", c.CommandPath())
+	}
+	return nil
+}
+
 // getAllOrLatestContainers tries to return the correct list of containers
 // depending if --all, --latest or <container-id> is used.
 // It requires the Context (c) and the Runtime (runtime). As different