Add gvfsd-metadata update daemon

This daemon singleton handles updates to metadata stores.
All clients that wishes to write metadata should talk to
it via dbus.

This way all writes are serialized to avoid data loss on
concurrent writes.

1 files changed, 573 insertions, 0 deletions

diff --git a/metadata/meta-daemon.c b/metadata/meta-daemon.c
new file mode 100644
index 00000000..f86e5819
--- /dev/null
+++ b/metadata/meta-daemon.c
@@ -0,0 +1,573 @@
+/* GIO - GLib Input, Output and Streaming Library
+ *
+ * Copyright (C) 2006-2007 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Author: Alexander Larsson <alexl@redhat.com>
+ */
+
+#include <config.h>
+
+#include <glib.h>
+#include <glib/gi18n.h>
+#include <glib/gstdio.h>
+#include <stdlib.h>
+#include <dbus/dbus.h>
+#include "gdbusutils.h"
+#include "metatree.h"
+#include "gvfsdaemonprotocol.h"
+
+#define WRITEOUT_TIMEOUT_SECS 60
+
+typedef struct {
+  char *filename;
+  MetaTree *tree;
+  guint writeout_timeout;
+} TreeInfo;
+
+static GHashTable *tree_infos = NULL;
+
+static void
+tree_info_free (TreeInfo *info)
+{
+  g_free (info->filename);
+  meta_tree_unref (info->tree);
+  if (info->writeout_timeout)
+    g_source_remove (info->writeout_timeout);
+
+  g_free (info);
+}
+
+static gboolean
+writeout_timeout (gpointer data)
+{
+  TreeInfo *info = data;
+
+  meta_tree_flush (info->tree);
+  info->writeout_timeout = 0;
+
+  return FALSE;
+}
+
+static void
+tree_info_schedule_writeout (TreeInfo *info)
+{
+  if (info->writeout_timeout == 0)
+    info->writeout_timeout =
+      g_timeout_add_seconds (WRITEOUT_TIMEOUT_SECS,
+			     writeout_timeout, info);
+}
+
+static TreeInfo *
+tree_info_new (const char *filename)
+{
+  TreeInfo *info;
+  MetaTree *tree;
+
+  tree = meta_tree_open (filename, TRUE);
+  if (tree == NULL)
+    return NULL;
+
+  info = g_new0 (TreeInfo, 1);
+  info->filename = g_strdup (filename);
+  info->tree = tree;
+  info->writeout_timeout = 0;
+
+  return info;
+}
+
+static TreeInfo *
+tree_info_lookup (const char *filename)
+{
+  TreeInfo *info;
+
+  info = g_hash_table_lookup (tree_infos, filename);
+  if (info)
+    return info;
+
+  info = tree_info_new (filename);
+  if (info)
+    g_hash_table_insert (tree_infos,
+			 info->filename,
+			 info);
+  return info;
+}
+
+static gboolean
+metadata_set (const char *treefile,
+	      const char *path,
+	      DBusMessageIter *iter,
+	      DBusError *derror)
+{
+  TreeInfo *info;
+  const char *str;
+  char **strv;
+  gboolean res;
+  const char *key;
+  int n_elements;
+
+  info = tree_info_lookup (treefile);
+  if (info == NULL)
+    {
+      dbus_set_error (derror,
+		      DBUS_ERROR_FILE_NOT_FOUND,
+		      _("Can't find metadata file %s"),
+		      treefile);
+      return FALSE;
+    }
+
+  res = TRUE;
+  while (dbus_message_iter_get_arg_type (iter) != 0)
+    {
+      if (!_g_dbus_message_iter_get_args (iter, derror,
+					  DBUS_TYPE_STRING, &key,
+					  0))
+	{
+	  res = FALSE;
+	  break;
+	}
+
+      if (dbus_message_iter_get_arg_type (iter) == DBUS_TYPE_ARRAY)
+	{
+	  /* stringv */
+	  if (!_g_dbus_message_iter_get_args (iter, derror,
+					      DBUS_TYPE_ARRAY, DBUS_TYPE_STRING, &strv, &n_elements,
+					      0))
+	    {
+	      res = FALSE;
+	      break;
+	    }
+	  if (!meta_tree_set_stringv (info->tree, path, key, strv))
+	    {
+	      dbus_set_error (derror,
+			      DBUS_ERROR_FAILED,
+			      _("Unable to set metadata key"));
+	      res = FALSE;
+	    }
+	  g_strfreev (strv);
+	}
+      else
+	{
+	  /* string */
+	  if (!_g_dbus_message_iter_get_args (iter, derror,
+					      DBUS_TYPE_STRING, &str,
+					      0))
+	    {
+	      res = FALSE;
+	      break;
+	    }
+	  if (!meta_tree_set_string (info->tree, path, key, str))
+	    {
+	      dbus_set_error (derror,
+			      DBUS_ERROR_FAILED,
+			      _("Unable to set metadata key"));
+	      res = FALSE;
+	    }
+	}
+    }
+
+  tree_info_schedule_writeout (info);
+
+  return res;
+}
+
+static gboolean
+metadata_unset (const char *treefile,
+		const char *path,
+		const char *key,
+		DBusError *derror)
+{
+  TreeInfo *info;
+
+  info = tree_info_lookup (treefile);
+  if (info == NULL)
+    {
+      dbus_set_error (derror,
+		      DBUS_ERROR_FILE_NOT_FOUND,
+		      _("Can't find metadata file %s"),
+		      treefile);
+      return FALSE;
+    }
+
+  if (!meta_tree_unset (info->tree, path, key))
+    {
+      dbus_set_error (derror,
+		      DBUS_ERROR_FAILED,
+		      _("Unable to unset metadata key"));
+      return FALSE;
+    }
+
+  tree_info_schedule_writeout (info);
+  return TRUE;
+}
+
+static gboolean
+metadata_remove (const char *treefile,
+		 const char *path,
+		 DBusError *derror)
+{
+  TreeInfo *info;
+
+  info = tree_info_lookup (treefile);
+  if (info == NULL)
+    {
+      dbus_set_error (derror,
+		      DBUS_ERROR_FILE_NOT_FOUND,
+		      _("Can't find metadata file %s"),
+		      treefile);
+      return FALSE;
+    }
+
+  if (!meta_tree_remove (info->tree, path))
+    {
+      dbus_set_error (derror,
+		      DBUS_ERROR_FAILED,
+		      _("Unable to remove metadata keys"));
+      return FALSE;
+    }
+
+  tree_info_schedule_writeout (info);
+  return TRUE;
+}
+
+static gboolean
+metadata_move (const char *treefile,
+	       const char *src_path,
+	       const char *dest_path,
+	       DBusError *derror)
+{
+  TreeInfo *info;
+
+  info = tree_info_lookup (treefile);
+  if (info == NULL)
+    {
+      dbus_set_error (derror,
+		      DBUS_ERROR_FILE_NOT_FOUND,
+		      _("Can't find metadata file %s"),
+		      treefile);
+      return FALSE;
+    }
+
+  /* Overwrites any dest */
+  if (!meta_tree_copy (info->tree, src_path, dest_path))
+    {
+      dbus_set_error (derror,
+		      DBUS_ERROR_FAILED,
+		      _("Unable to move metadata keys"));
+      return FALSE;
+    }
+
+  /* Remove source if copy succeeded (ignoring errors) */
+  meta_tree_remove (info->tree, src_path);
+
+  tree_info_schedule_writeout (info);
+  return TRUE;
+}
+
+static gboolean
+register_name (DBusConnection *conn,
+	       gboolean replace)
+{
+  DBusError error;
+  unsigned int flags;
+  int ret;
+
+  flags = DBUS_NAME_FLAG_ALLOW_REPLACEMENT | DBUS_NAME_FLAG_DO_NOT_QUEUE;
+  if (replace)
+    flags |= DBUS_NAME_FLAG_REPLACE_EXISTING;
+
+  ret = dbus_bus_request_name (conn, G_VFS_DBUS_METADATA_NAME, flags, &error);
+  if (ret == -1)
+    {
+      g_printerr ("Failed to acquire daemon name: %s", error.message);
+      dbus_error_free (&error);
+      return FALSE;
+    }
+  else if (ret == DBUS_REQUEST_NAME_REPLY_EXISTS)
+    {
+      g_printerr ("VFS daemon already running, exiting.\n");
+      return FALSE;
+    }
+  else if (ret != DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER)
+    {
+      g_printerr ("Not primary owner of the service, exiting.\n");
+      return FALSE;
+    }
+  return TRUE;
+}
+
+static DBusHandlerResult
+dbus_message_filter_func (DBusConnection *conn,
+			  DBusMessage    *message,
+			  gpointer        data)
+{
+  char *name;
+
+  if (dbus_message_is_signal (message, DBUS_INTERFACE_DBUS, "NameLost"))
+    {
+      if (dbus_message_get_args (message, NULL,
+				 DBUS_TYPE_STRING, &name,
+				 DBUS_TYPE_INVALID) &&
+	  strcmp (name, G_VFS_DBUS_METADATA_NAME) == 0)
+	{
+	  /* Someone else got the name (i.e. someone used --replace), exit */
+	  exit (1);
+	}
+    }
+
+  return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+static void
+metadata_unregistered (DBusConnection  *connection,
+		       void            *user_data)
+{
+}
+
+static DBusHandlerResult
+metadata_message (DBusConnection  *connection,
+		  DBusMessage     *message,
+		  void            *user_data)
+{
+  DBusMessageIter iter;
+  DBusError derror;
+  DBusMessage *reply;
+  char *treefile;
+  char *path, *dest_path;
+  const char *key;
+
+  reply = NULL;
+  dbus_message_iter_init (message, &iter);
+  dbus_error_init (&derror);
+
+  if (dbus_message_is_method_call (message,
+				   G_VFS_DBUS_METADATA_INTERFACE,
+				   G_VFS_DBUS_METADATA_OP_SET))
+    {
+      treefile = NULL;
+      path = NULL;
+      if (!_g_dbus_message_iter_get_args (&iter, &derror,
+					  G_DBUS_TYPE_CSTRING, &treefile,
+					  G_DBUS_TYPE_CSTRING, &path,
+					  0) ||
+	  !metadata_set (treefile, path, &iter, &derror))
+	{
+	  reply = dbus_message_new_error (message,
+					  derror.name,
+					  derror.message);
+	  dbus_error_free (&derror);
+	}
+      else
+	reply = dbus_message_new_method_return (message);
+
+      g_free (treefile);
+      g_free (path);
+    }
+
+  else if (dbus_message_is_method_call (message,
+				   G_VFS_DBUS_METADATA_INTERFACE,
+				   G_VFS_DBUS_METADATA_OP_UNSET))
+    {
+      treefile = NULL;
+      path = NULL;
+      if (!_g_dbus_message_iter_get_args (&iter, &derror,
+					  G_DBUS_TYPE_CSTRING, &treefile,
+					  G_DBUS_TYPE_CSTRING, &path,
+					  DBUS_TYPE_STRING, &key,
+					  0) ||
+	  !metadata_unset (treefile, path, key, &derror))
+	{
+	  reply = dbus_message_new_error (message,
+					  derror.name,
+					  derror.message);
+	  dbus_error_free (&derror);
+	}
+      else
+	reply = dbus_message_new_method_return (message);
+
+      g_free (treefile);
+      g_free (path);
+    }
+
+  else if (dbus_message_is_method_call (message,
+					G_VFS_DBUS_METADATA_INTERFACE,
+					G_VFS_DBUS_METADATA_OP_REMOVE))
+    {
+      treefile = NULL;
+      path = NULL;
+      if (!_g_dbus_message_iter_get_args (&iter, &derror,
+					  G_DBUS_TYPE_CSTRING, &treefile,
+					  G_DBUS_TYPE_CSTRING, &path,
+					  0) ||
+	  !metadata_remove (treefile, path, &derror))
+	{
+	  reply = dbus_message_new_error (message,
+					  derror.name,
+					  derror.message);
+	  dbus_error_free (&derror);
+	}
+      else
+	reply = dbus_message_new_method_return (message);
+
+      g_free (treefile);
+      g_free (path);
+    }
+
+  else if (dbus_message_is_method_call (message,
+					G_VFS_DBUS_METADATA_INTERFACE,
+					G_VFS_DBUS_METADATA_OP_MOVE))
+    {
+      treefile = NULL;
+      path = NULL;
+      dest_path = NULL;
+      if (!_g_dbus_message_iter_get_args (&iter, &derror,
+					  G_DBUS_TYPE_CSTRING, &treefile,
+					  G_DBUS_TYPE_CSTRING, &path,
+					  G_DBUS_TYPE_CSTRING, &dest_path,
+					  0) ||
+	  !metadata_move (treefile, path, dest_path, &derror))
+	{
+	  reply = dbus_message_new_error (message,
+					  derror.name,
+					  derror.message);
+	  dbus_error_free (&derror);
+	}
+      else
+	reply = dbus_message_new_method_return (message);
+
+      g_free (treefile);
+      g_free (path);
+    }
+
+  if (reply)
+    {
+      dbus_connection_send (connection, reply, NULL);
+      dbus_message_unref (reply);
+      return DBUS_HANDLER_RESULT_HANDLED;
+    }
+  else
+    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+static struct DBusObjectPathVTable metadata_dbus_vtable = {
+  metadata_unregistered,
+  metadata_message
+};
+
+int
+main (int argc, char *argv[])
+{
+  GMainLoop *loop;
+  DBusConnection *conn;
+  gboolean replace;
+  GError *error;
+  DBusError derror;
+  GOptionContext *context;
+  const GOptionEntry options[] = {
+    { "replace", 'r', 0, G_OPTION_ARG_NONE, &replace,  N_("Replace old daemon."), NULL },
+    { NULL }
+  };
+
+  setlocale (LC_ALL, "");
+
+  bindtextdomain (GETTEXT_PACKAGE, GVFS_LOCALEDIR);
+  bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
+  textdomain (GETTEXT_PACKAGE);
+
+  g_set_application_name (_("GVFS Metadata Daemon"));
+  context = g_option_context_new ("");
+
+  g_option_context_set_summary (context, _("Main daemon for GVFS"));
+
+  g_option_context_add_main_entries (context, options, GETTEXT_PACKAGE);
+
+  replace = FALSE;
+
+  error = NULL;
+  if (!g_option_context_parse (context, &argc, &argv, &error))
+    {
+      /* Translators: the first %s is the application name, */
+      /* the second %s is the error message                 */
+      g_printerr (_("%s: %s"), g_get_application_name(), error->message);
+      g_printerr ("\n");
+      g_printerr (_("Try \"%s --help\" for more information."),
+		  g_get_prgname ());
+      g_printerr ("\n");
+      g_error_free (error);
+      g_option_context_free (context);
+      return 1;
+    }
+
+  g_option_context_free (context);
+
+  g_type_init ();
+
+  loop = g_main_loop_new (NULL, FALSE);
+
+  dbus_error_init (&derror);
+  conn = dbus_bus_get (DBUS_BUS_SESSION, &derror);
+  if (!conn)
+    {
+      g_printerr ("Failed to connect to the D-BUS daemon: %s\n",
+		  derror.message);
+
+      dbus_error_free (&derror);
+      return 1;
+    }
+
+  dbus_bus_add_match (conn,
+		      "type='signal',"
+		      "interface='org.freedesktop.DBus',"
+		      "member='NameOwnerChanged',"
+		      "arg0='"G_VFS_DBUS_METADATA_NAME"'",
+		      &derror);
+  if (dbus_error_is_set (&derror))
+    {
+      g_printerr ("Failed to add dbus match: %s\n", derror.message);
+      dbus_error_free (&derror);
+      return 1;
+    }
+
+  if (!dbus_connection_add_filter (conn,
+				   dbus_message_filter_func, NULL, NULL))
+    {
+      g_printerr ("Failed to add dbus filter\n");
+      return 1;
+    }
+
+  if (!dbus_connection_register_object_path (conn,
+					     G_VFS_DBUS_METADATA_PATH,
+					     &metadata_dbus_vtable, NULL))
+    {
+      g_printerr ("Failed to register object path\n");
+      return 1;
+    }
+
+  if (!register_name (conn, replace))
+    return 1;
+
+  _g_dbus_connection_integrate_with_main (conn);
+
+  tree_infos = g_hash_table_new_full (g_str_hash,
+				      g_str_equal,
+				      NULL,
+				      (GDestroyNotify)tree_info_free);
+
+  g_main_loop_run (loop);
+
+  return 0;
+}