Add new UpdateActivationEnvironment bus message

It adjusts the environment of activated bus clients.
This is important for session managers that get started
after the session bus daemon and want to influence the
environment of desktop services that are started by the
bus.

3 files changed, 169 insertions, 0 deletions

diff --git a/bus/driver.c b/bus/driver.c
index bdf5afbe..05ecd56c 100644
--- a/bus/driver.c
+++ b/bus/driver.c
@@ -811,6 +811,133 @@ send_ack_reply (DBusConnection *connection,
 }
 
 static dbus_bool_t
+bus_driver_handle_update_activation_environment (DBusConnection *connection,
+                                                 BusTransaction *transaction,
+                                                 DBusMessage    *message,
+                                                 DBusError      *error)
+{
+  dbus_bool_t retval;
+  BusActivation *activation;
+  DBusMessageIter iter;
+  DBusMessageIter dict_iter;
+  DBusMessageIter dict_entry_iter;
+  int msg_type;
+  int array_type;
+  int key_type;
+  DBusList *keys, *key_link;
+  DBusList *values, *value_link;
+
+  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
+
+  activation = bus_connection_get_activation (connection);
+
+  dbus_message_iter_init (message, &iter);
+
+  /* The message signature has already been checked for us,
+   * so let's just assert it's right.
+   */
+  msg_type = dbus_message_iter_get_arg_type (&iter);
+
+  _dbus_assert (msg_type == DBUS_TYPE_ARRAY);
+
+  dbus_message_iter_recurse (&iter, &dict_iter);
+
+  retval = FALSE;
+
+  /* Then loop through the sent dictionary, add the location of
+   * the environment keys and values to lists. The result will
+   * be in reverse order, so we don't have to constantly search
+   * for the end of the list in a loop.
+   */
+  keys = NULL;
+  values = NULL;
+  while ((array_type = dbus_message_iter_get_arg_type (&dict_iter)) == DBUS_TYPE_DICT_ENTRY)
+    {
+      dbus_message_iter_recurse (&dict_iter, &dict_entry_iter);
+
+      while ((key_type = dbus_message_iter_get_arg_type (&dict_entry_iter)) == DBUS_TYPE_STRING)
+        {
+          char *key;
+          char *value;
+          int value_type;
+
+          dbus_message_iter_get_basic (&dict_entry_iter, &key);
+          dbus_message_iter_next (&dict_entry_iter);
+
+          value_type = dbus_message_iter_get_arg_type (&dict_entry_iter);
+
+          if (value_type != DBUS_TYPE_STRING)
+            break;
+
+          dbus_message_iter_get_basic (&dict_entry_iter, &value);
+
+          if (!_dbus_list_append (&keys, key))
+            {
+              BUS_SET_OOM (error);
+              break;
+            }
+
+          if (!_dbus_list_append (&values, value))
+            {
+              BUS_SET_OOM (error);
+              break;
+            }
+
+          dbus_message_iter_next (&dict_entry_iter);
+        }
+
+      if (key_type != DBUS_TYPE_INVALID)
+        break;
+
+      dbus_message_iter_next (&dict_iter);
+    }
+
+  if (array_type != DBUS_TYPE_INVALID)
+    goto out;
+
+  _dbus_assert (_dbus_list_get_length (&keys) == _dbus_list_get_length (&values));
+
+  key_link = keys;
+  value_link = values;
+  while (key_link != NULL)
+  {
+      const char *key;
+      const char *value;
+
+      key = key_link->data;
+      value = value_link->data;
+
+      if (!bus_activation_set_environment_variable (activation,
+                                                    key, value, error))
+      {
+          _DBUS_ASSERT_ERROR_IS_SET (error);
+          _dbus_verbose ("bus_activation_set_environment_variable() failed\n");
+          break;
+      }
+      key_link = _dbus_list_get_next_link (&keys, key_link);
+      value_link = _dbus_list_get_next_link (&values, value_link);
+  }
+
+  /* FIXME: We can fail early having set only some of the environment variables,
+   * (because of OOM failure).  It's sort of hard to fix and it doesn't really
+   * matter, so we're punting for now.
+   */
+  if (key_link != NULL)
+    goto out;
+
+  if (!send_ack_reply (connection, transaction,
+                       message, error))
+    goto out;
+
+  retval = TRUE;
+
+ out:
+  _dbus_list_clear (&keys);
+  _dbus_list_clear (&values);
+  return retval;
+}
+
+static dbus_bool_t
 bus_driver_handle_add_match (DBusConnection *connection,
                              BusTransaction *transaction,
                              DBusMessage    *message,
@@ -1542,6 +1669,10 @@ struct
     DBUS_TYPE_STRING_AS_STRING DBUS_TYPE_UINT32_AS_STRING,
     DBUS_TYPE_UINT32_AS_STRING,
     bus_driver_handle_activate_service },
+  { "UpdateActivationEnvironment",
+    DBUS_TYPE_ARRAY_AS_STRING DBUS_DICT_ENTRY_BEGIN_CHAR_AS_STRING DBUS_TYPE_STRING_AS_STRING DBUS_TYPE_STRING_AS_STRING DBUS_DICT_ENTRY_END_CHAR_AS_STRING,
+    "",
+    bus_driver_handle_update_activation_environment },
   { "NameHasOwner",
     DBUS_TYPE_STRING_AS_STRING,
     DBUS_TYPE_BOOLEAN_AS_STRING,
diff --git a/bus/system.conf.in b/bus/system.conf.in
index bb468bb9..6a71926e 100644
--- a/bus/system.conf.in
+++ b/bus/system.conf.in
@@ -53,6 +53,10 @@
     <!-- valid replies are always allowed -->
     <allow send_requested_reply="true"/>
     <allow receive_requested_reply="true"/>
+    <!-- disallow changing the activation environment of system services -->
+    <deny send_destination="org.freedesktop.DBus"
+          send_interface="org.freedesktop.DBus"
+          send_member="UpdateActivationEnvironment"/>
   </policy>
 
   <!-- Config files are placed here that among other things, punch 
diff --git a/doc/dbus-specification.xml b/doc/dbus-specification.xml
index 932ba0a3..9b22c84a 100644
--- a/doc/dbus-specification.xml
+++ b/doc/dbus-specification.xml
@@ -3678,6 +3678,40 @@
 
       </sect3>
 
+      <sect3 id="bus-messages-update-activation-environment">
+        <title><literal>org.freedesktop.DBus.UpdateActivationEnvironment</literal></title>
+        <para>
+          As a method:
+          <programlisting>
+            UpdateActivationEnvironment (in ARRAY of DICT&lt;STRING,STRING&gt; environment)
+          </programlisting>
+          Message arguments:
+          <informaltable>
+            <tgroup cols="3">
+              <thead>
+                <row>
+                  <entry>Argument</entry>
+                  <entry>Type</entry>
+                  <entry>Description</entry>
+                </row>
+              </thead>
+              <tbody>
+                <row>
+                  <entry>0</entry>
+                  <entry>ARRAY of DICT&lt;STRING,STRING&gt;</entry>
+                  <entry>Environment to add or update</entry>
+                </row>
+              </tbody>
+            </tgroup>
+            </informaltable>
+            Normally, session bus activated services inherit the environment of the bus daemon.  This method adds to or modifies that environment when activating services.
+        </para>
+        <para>
+          Some bus instances, such as the standard system bus, may disable access to this method for some or all callers.
+        </para>
+
+      </sect3>
+
       <sect3 id="bus-messages-get-name-owner">
         <title><literal>org.freedesktop.DBus.GetNameOwner</literal></title>
         <para>