Added new method for wallet-backend, update

update will work generally like get, but only for objects that have a
concept of updating content automatically, like keytabs and passwords.
For these, the content will be updated before sending to the client.

In a later release get for keytabs will be modified to never update the
kvno before sending to the user, and so the unchanging flag will be
phased out in lieu of explicitly using the method that does what you
want.

Change-Id: I96a84416c5e50278eb29fe07052dde6e063bc071

4 files changed, 89 insertions, 26 deletions

diff --git a/perl/lib/Wallet/Object/Base.pm b/perl/lib/Wallet/Object/Base.pm
index bdd61fb..97e6127 100644
--- a/perl/lib/Wallet/Object/Base.pm
+++ b/perl/lib/Wallet/Object/Base.pm
@@ -609,6 +609,15 @@ sub history {
 # The get methods must always be overridden by the subclass.
 sub get { die "Do not instantiate Wallet::Object::Base directly\n"; }
 
+# The update method should only work if a subclass supports it as something
+# different from get.  That makes it explicit about whether the subclass has
+# a meaningful update.
+sub update {
+    my ($self) = @_;
+    $self->error ("update is not supported for this type, use get instead");
+    return;
+}
+
 # Provide a default store implementation that returns an immutable object
 # error so that auto-generated types don't have to provide their own.
 sub store {
diff --git a/perl/lib/Wallet/Object/Keytab.pm b/perl/lib/Wallet/Object/Keytab.pm
index 975179b..c625766 100644
--- a/perl/lib/Wallet/Object/Keytab.pm
+++ b/perl/lib/Wallet/Object/Keytab.pm
@@ -29,6 +29,37 @@ use Wallet::Kadmin;
 $VERSION = '0.09';
 
 ##############################################################################
+# Shared methods
+##############################################################################
+
+# Generate a keytab into a temporary file and then return that as the return
+# value.  Used by both get and update, as the only difference is how we
+# handle the unchanging flag.
+sub retrieve {
+    my ($self, $operation, $user, $host, $time) = @_;
+    $time ||= time;
+    my $id = $self->{type} . ':' . $self->{name};
+    if ($self->flag_check ('locked')) {
+        $self->error ("cannot get $id: object is locked");
+        return;
+    }
+    my $kadmin = $self->{kadmin};
+    my $result;
+    if ($operation eq 'get' && $self->flag_check ('unchanging')) {
+        $result = $kadmin->keytab ($self->{name});
+    } else {
+        my @enctypes = $self->attr ('enctypes');
+        $result = $kadmin->keytab_rekey ($self->{name}, @enctypes);
+    }
+    if (defined $result) {
+        $self->log_action ($operation, $user, $host, $time);
+    } else {
+        $self->error ($kadmin->error);
+    }
+    return $result;
+}
+
+##############################################################################
 # Enctype restriction
 ##############################################################################
 
@@ -314,25 +345,15 @@ sub destroy {
 # return that as the return value.
 sub get {
     my ($self, $user, $host, $time) = @_;
-    $time ||= time;
-    my $id = $self->{type} . ':' . $self->{name};
-    if ($self->flag_check ('locked')) {
-        $self->error ("cannot get $id: object is locked");
-        return;
-    }
-    my $kadmin = $self->{kadmin};
-    my $result;
-    if ($self->flag_check ('unchanging')) {
-        $result = $kadmin->keytab ($self->{name});
-    } else {
-        my @enctypes = $self->attr ('enctypes');
-        $result = $kadmin->keytab_rekey ($self->{name}, @enctypes);
-    }
-    if (defined $result) {
-        $self->log_action ('get', $user, $host, $time);
-    } else {
-        $self->error ($kadmin->error);
-    }
+    my $result = $self->retrieve ('get', $user, $host, $time);
+    return $result;
+}
+
+# Our update implementation.  Generate a new keytab regardless of the
+# unchanging flag.
+sub update {
+    my ($self, $user, $host, $time) = @_;
+    my $result = $self->retrieve ('update', $user, $host, $time);
     return $result;
 }
 
diff --git a/perl/lib/Wallet/Object/Password.pm b/perl/lib/Wallet/Object/Password.pm
index d06c8a6..3fd6ec8 100644
--- a/perl/lib/Wallet/Object/Password.pm
+++ b/perl/lib/Wallet/Object/Password.pm
@@ -57,12 +57,12 @@ sub file_path {
 }
 
 ##############################################################################
-# Core methods
+# Shared methods
 ##############################################################################
 
 # Return the contents of the file.
-sub get {
-    my ($self, $user, $host, $time) = @_;
+sub retrieve {
+    my ($self, $operation, $user, $host, $time) = @_;
     $time ||= time;
     my $id = $self->{type} . ':' . $self->{name};
     if ($self->flag_check ('locked')) {
@@ -72,13 +72,13 @@ sub get {
     my $path = $self->file_path;
     return unless $path;
 
-    # If nothing is yet stored, generate a random password and save it to
-    # the file.
+    # If nothing is yet stored, or we have requested an update, generate a
+    # random password and save it to the file.
     my $schema = $self->{schema};
     my %search = (ob_type => $self->{type},
                   ob_name => $self->{name});
     my $object = $schema->resultset('Object')->find (\%search);
-    unless ($object->ob_stored_on) {
+    if (!$object->ob_stored_on || $operation eq 'update') {
         unless (open (FILE, '>', $path)) {
             $self->error ("cannot store initial settings for $id: $!\n");
             return;
@@ -103,10 +103,28 @@ sub get {
         $self->error ("cannot get $id: $!");
         return;
     }
-    $self->log_action ('get', $user, $host, $time);
+    $self->log_action ($operation, $user, $host, $time);
     return $data;
 }
 
+##############################################################################
+# Core methods
+##############################################################################
+
+# Return the contents of the file.
+sub get {
+    my ($self, $user, $host, $time) = @_;
+    my $result = $self->retrieve ('get', $user, $host, $time);
+    return $result;
+}
+
+# Return the contents of the file after resetting them to a random string.
+sub update {
+    my ($self, $user, $host, $time) = @_;
+    my $result = $self->retrieve ('update', $user, $host, $time);
+    return $result;
+}
+
 1;
 __END__
 
diff --git a/perl/lib/Wallet/Server.pm b/perl/lib/Wallet/Server.pm
index 6af0570..3ef5954 100644
--- a/perl/lib/Wallet/Server.pm
+++ b/perl/lib/Wallet/Server.pm
@@ -516,6 +516,21 @@ sub get {
     return $result;
 }
 
+# Retrieve the information associated with an object, updating the current
+# information if we are of a type that allows autogenerated information.
+# Returns undef and sets the internal error if the retrieval fails or if the
+# user isn't authorized.  If the object doesn't exist, attempts dynamic
+# creation of the object using the default ACL mappings (if any).
+sub update {
+    my ($self, $type, $name) = @_;
+    my $object = $self->retrieve ($type, $name);
+    return unless defined $object;
+    return unless $self->acl_verify ($object, 'get');
+    my $result = $object->update ($self->{user}, $self->{host});
+    $self->error ($object->error) unless defined $result;
+    return $result;
+}
+
 # Store new data in an object, or returns undef and sets the internal error if
 # the object can't be found or if the user isn't authorized.  Also don't
 # permit storing undef, although storing the empty string is fine.  If the