client: avoid "Use of uninitialized value in pattern match (m//)" perl warnings.

When the accountd socket can't be reached.

1 files changed, 5 insertions, 2 deletions

diff --git a/client b/client
index bcdf6cd..e29d2a0 100755
--- a/client
+++ b/client
@@ -75,8 +75,11 @@ open (my $S, '+<&=', $1+0) or die "fdopen $1: $!";
 # Read the protocol version and JSON Web Key (RFC 7517) from the
 # lacme-accountd socket
 #
-die "Error: Invalid client version\n" unless
-    $S->getline() =~ /\A(\d+) OK(?:.*)\r\n\z/ and $1 == $PROTOCOL_VERSION;
+do {
+    my $greeting = $S->getline();
+    die "Error: Invalid client version\n" unless defined $greeting and
+        $greeting =~ /\A(\d+) OK(?:.*)\r\n\z/ and $1 == $PROTOCOL_VERSION;
+};
 my $JWK = JSON::->new->decode($S->getline());
 my $KID;