text: /*
   * Copyright © 2008 Kristian Høgsberg
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice (including the
   * next paragraph) shall be included in all copies or substantial
   * portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  #define _GNU_SOURCE
  
  #include <stdlib.h>
  #include <stdint.h>
  #include <stddef.h>
  #include <stdio.h>
  #include <stdarg.h>
  #include <stdbool.h>
  #include <errno.h>
  #include <string.h>
  #include <unistd.h>
  #include <sys/socket.h>
  #include <sys/un.h>
  #include <dlfcn.h>
  #include <assert.h>
  #include <sys/time.h>
  #include <fcntl.h>
  #include <sys/file.h>
  #include <sys/stat.h>
  #include <ffi.h>
  
  #include "wayland-private.h"
  #include "wayland-server.h"
  #include "wayland-server-protocol.h"
  #include "wayland-os.h"
  
  /* This is the size of the char array in struct sock_addr_un.
   * No Wayland socket can be created with a path longer than this,
   * including the null terminator.
   */
  #ifndef UNIX_PATH_MAX
  #define UNIX_PATH_MAX	108
  #endif
  
  #define LOCK_SUFFIX	".lock"
  #define LOCK_SUFFIXLEN	5
  
  struct wl_socket {
  	int fd;
  	int fd_lock;
  	struct sockaddr_un addr;
  	char lock_addr[UNIX_PATH_MAX + LOCK_SUFFIXLEN];
  	struct wl_list link;
  	struct wl_event_source *source;
  	char *display_name;
  };
  
  struct wl_client {
  	struct wl_connection *connection;
  	struct wl_event_source *source;
  	struct wl_display *display;
  	struct wl_resource *display_resource;
  	uint32_t id_count;
  	uint32_t mask;
  	struct wl_list link;
  	struct wl_map objects;
  	struct wl_signal destroy_signal;
  	struct ucred ucred;
  	int error;
  };
  
  struct wl_display {
  	struct wl_event_loop *loop;
  	int run;
  
  	uint32_t id;
  	uint32_t serial;
  
  	struct wl_list registry_resource_list;
  	struct wl_list global_list;
  	struct wl_list socket_list;
  	struct wl_list client_list;
  
  	struct wl_signal destroy_signal;
  
  	struct wl_array additional_shm_formats;
  };
  
  struct wl_global {
  	struct wl_display *display;
  	const struct wl_interface *interface;
  	uint32_t name;
  	uint32_t version;
  	void *data;
  	wl_global_bind_func_t bind;
  	struct wl_list link;
  };
  
  struct wl_resource {
  	struct wl_object object;
  	wl_resource_destroy_func_t destroy;
  	struct wl_list link;
  	struct wl_signal destroy_signal;
  	struct wl_client *client;
  	void *data;
  	int version;
  	wl_dispatcher_func_t dispatcher;
  };
  
  static int debug_server = 0;
  
  WL_EXPORT void
  wl_resource_post_event_array(struct wl_resource *resource, uint32_t opcode,
  			     union wl_argument *args)
  {
  	struct wl_closure *closure;
  	struct wl_object *object = &resource->object;
  
  	closure = wl_closure_marshal(object, opcode, args,
  				     &object->interface->events[opcode]);
  
  	if (closure == NULL) {
  		resource->client->error = 1;
  		return;
  	}
  
  	if (wl_closure_send(closure, resource->client->connection))
  		resource->client->error = 1;
  
  	if (debug_server)
  		wl_closure_print(closure, object, true);
  
  	wl_closure_destroy(closure);
  }
  
  WL_EXPORT void
  wl_resource_post_event(struct wl_resource *resource, uint32_t opcode, ...)
  {
  	union wl_argument args[WL_CLOSURE_MAX_ARGS];
  	struct wl_object *object = &resource->object;
  	va_list ap;
  
  	va_start(ap, opcode);
  	wl_argument_from_va_list(object->interface->events[opcode].signature,
  				 args, WL_CLOSURE_MAX_ARGS, ap);
  	va_end(ap);
  
  	wl_resource_post_event_array(resource, opcode, args);
  }
  
  
  WL_EXPORT void
  wl_resource_queue_event_array(struct wl_resource *resource, uint32_t opcode,
  			      union wl_argument *args)
  {
  	struct wl_closure *closure;
  	struct wl_object *object = &resource->object;
  
  	closure = wl_closure_marshal(object, opcode, args,
  				     &object->interface->events[opcode]);
  
  	if (closure == NULL) {
  		resource->client->error = 1;
  		return;
  	}
  
  	if (wl_closure_queue(closure, resource->client->connection))
  		resource->client->error = 1;
  
  	if (debug_server)
  		wl_closure_print(closure, object, true);
  
  	wl_closure_destroy(closure);
  }
  
  WL_EXPORT void
  wl_resource_queue_event(struct wl_resource *resource, uint32_t opcode, ...)
  {
  	union wl_argument args[WL_CLOSURE_MAX_ARGS];
  	struct wl_object *object = &resource->object;
  	va_list ap;
  
  	va_start(ap, opcode);
  	wl_argument_from_va_list(object->interface->events[opcode].signature,
  				 args, WL_CLOSURE_MAX_ARGS, ap);
  	va_end(ap);
  
  	wl_resource_queue_event_array(resource, opcode, args);
  }
  
  WL_EXPORT void
  wl_resource_post_error(struct wl_resource *resource,
  		       uint32_t code, const char *msg, ...)
  {
  	struct wl_client *client = resource->client;
  	char buffer[128];
  	va_list ap;
  
  	va_start(ap, msg);
  	vsnprintf(buffer, sizeof buffer, msg, ap);
  	va_end(ap);
  
  	client->error = 1;
  
  	/*
  	 * When a client aborts, its resources are destroyed in id order,
  	 * which means the display resource is destroyed first. If destruction
  	 * of any later resources results in a protocol error, we end up here
  	 * with a NULL display_resource. Do not try to send errors to an
  	 * already dead client.
  	 */
  	if (!client->display_resource)
  		return;
  
  	wl_resource_post_event(client->display_resource,
  			       WL_DISPLAY_ERROR, resource, code, buffer);
  }
  
  static int
  wl_client_connection_data(int fd, uint32_t mask, void *data)
  {
  	struct wl_client *client = data;
  	struct wl_connection *connection = client->connection;
  	struct wl_resource *resource;
  	struct wl_object *object;
  	struct wl_closure *closure;
  	const struct wl_message *message;
  	uint32_t p[2];
  	uint32_t resource_flags;
  	int opcode, size, since;
  	int len;
  
  	if (mask & (WL_EVENT_ERROR | WL_EVENT_HANGUP)) {
  		wl_client_destroy(client);
  		return 1;
  	}
  
  	if (mask & WL_EVENT_WRITABLE) {
  		len = wl_connection_flush(connection);
  		if (len < 0 && errno != EAGAIN) {
  			wl_client_destroy(client);
  			return 1;
  		} else if (len >= 0) {
  			wl_event_source_fd_update(client->source,
  						  WL_EVENT_READABLE);
  		}
  	}
  
  	len = 0;
  	if (mask & WL_EVENT_READABLE) {
  		len = wl_connection_read(connection);
  		if (len == 0 || (len < 0 && errno != EAGAIN)) {
  			wl_client_destroy(client);
  			return 1;
  		}
  	}
  
  	while ((size_t) len >= sizeof p) {
  		wl_connection_copy(connection, p, sizeof p);
  		opcode = p[1] & 0xffff;
  		size = p[1] >> 16;
  		if (len < size)
  			break;
  
  		resource = wl_map_lookup(&client->objects, p[0]);
  		resource_flags = wl_map_lookup_flags(&client->objects, p[0]);
  		if (resource == NULL) {
  			wl_resource_post_error(client->display_resource,
  					       WL_DISPLAY_ERROR_INVALID_OBJECT,
  					       "invalid object %u", p[0]);
  			break;
  		}
  
  		object = &resource->object;
  		if (opcode >= object->interface->method_count) {
  			wl_resource_post_error(client->display_resource,
  					       WL_DISPLAY_ERROR_INVALID_METHOD,
  					       "invalid method %d, object %s@%u",
  					       opcode,
  					       object->interface->name,
  					       object->id);
  			break;
  		}
  
  		message = &object->interface->methods[opcode];
  		since = wl_message_get_since(message);
  		if (!(resource_flags & WL_MAP_ENTRY_LEGACY) &&
  		    resource->version > 0 && resource->version < since) {
  			wl_resource_post_error(client->display_resource,
  					       WL_DISPLAY_ERROR_INVALID_METHOD,
  					       "invalid method %d (since %d < %d)"
  					       ", object %s@%u",
  					       opcode, resource->version, since,
  					       object->interface->name,
  					       object->id);
  			break;
  		}
  
  
  		closure = wl_connection_demarshal(client->connection, size,
  						  &client->objects, message);
  		len -= size;
  
  		if (closure == NULL && errno == ENOMEM) {
  			wl_resource_post_no_memory(resource);
  			break;
  		} else if (closure == NULL ||
  			   wl_closure_lookup_objects(closure, &client->objects) < 0) {
  			wl_resource_post_error(client->display_resource,
  					       WL_DISPLAY_ERROR_INVALID_METHOD,
  					       "invalid arguments for %s@%u.%s",
  					       object->interface->name,
  					       object->id,
  					       message->name);
  			wl_closure_destroy(closure);
  			break;
  		}
  
  		if (debug_server)
  			wl_closure_print(closure, object, false);
  
  		if ((resource_flags & WL_MAP_ENTRY_LEGACY) ||
  		    resource->dispatcher == NULL) {
  			wl_closure_invoke(closure, WL_CLOSURE_INVOKE_SERVER,
  					  object, opcode, client);
  		} else {
  			wl_closure_dispatch(closure, resource->dispatcher,
  					    object, opcode);
  		}
  
  		wl_closure_destroy(closure);
  
  		if (client->error)
  			break;
  	}
  
  	if (client->error)
  		wl_client_destroy(client);
  
  	return 1;
  }
  
  /** Flush pending events to the client
   *
   * \param client The client object
   *
   * Events sent to clients are queued in a buffer and written to the
   * socket later - typically when the compositor has handled all
   * requests and goes back to block in the event loop.  This function
   * flushes all queued up events for a client immediately.
   *
   * \memberof wl_client
   */
  WL_EXPORT void
  wl_client_flush(struct wl_client *client)
  {
  	wl_connection_flush(client->connection);
  }
  
  /** Get the display object for the given client
   *
   * \param client The client object
   * \return The display object the client is associated with.
   *
   * \memberof wl_client
   */
  WL_EXPORT struct wl_display *
  wl_client_get_display(struct wl_client *client)
  {
  	return client->display;
  }
  
  static int
  bind_display(struct wl_client *client, struct wl_display *display);
  
  /** Create a client for the given file descriptor
   *
   * \param display The display object
   * \param fd The file descriptor for the socket to the client
   * \return The new client object or NULL on failure.
   *
   * Given a file descriptor corresponding to one end of a socket, this
   * function will create a wl_client struct and add the new client to
   * the compositors client list.  At that point, the client is
   * initialized and ready to run, as if the client had connected to the
   * servers listening socket.  When the client eventually sends
   * requests to the compositor, the wl_client argument to the request
   * handler will be the wl_client returned from this function.
   *
   * The other end of the socket can be passed to
   * wl_display_connect_to_fd() on the client side or used with the
   * WAYLAND_SOCKET environment variable on the client side.
   *
   * On failure this function sets errno accordingly and returns NULL.
   *
   * \memberof wl_display
   */
  WL_EXPORT struct wl_client *
  wl_client_create(struct wl_display *display, int fd)
  {
  	struct wl_client *client;
  	socklen_t len;
  
  	client = malloc(sizeof *client);
  	if (client == NULL)
  		return NULL;
  
  	memset(client, 0, sizeof *client);
  	client->display = display;
  	client->source = wl_event_loop_add_fd(display->loop, fd,
  					      WL_EVENT_READABLE,
  					      wl_client_connection_data, client);
  
  	if (!client->source)
  		goto err_client;
  
  	len = sizeof client->ucred;
  	if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED,
  		       &client->ucred, &len) < 0)
  		goto err_source;
  
  	client->connection = wl_connection_create(fd);
  	if (client->connection == NULL)
  		goto err_source;
  
  	wl_map_init(&client->objects, WL_MAP_SERVER_SIDE);
  
  	if (wl_map_insert_at(&client->objects, 0, 0, NULL) < 0)
  		goto err_map;
  
  	wl_signal_init(&client->destroy_signal);
  	if (bind_display(client, display) < 0)
  		goto err_map;
  
  	wl_list_insert(display->client_list.prev, &client->link);
  
  	return client;
  
  err_map:
  	wl_map_release(&client->objects);
  	wl_connection_destroy(client->connection);
  err_source:
  	wl_event_source_remove(client->source);
  err_client:
  	free(client);
  	return NULL;
  }
  
  /** Return Unix credentials for the client
   *
   * \param client The display object
   * \param pid Returns the process ID
   * \param uid Returns the user ID
   * \param gid Returns the group ID
   *
   * This function returns the process ID, the user ID and the group ID
   * for the given client.  The credentials come from getsockopt() with
   * SO_PEERCRED, on the client socket fd.  All the pointers can be
   * NULL, if the caller is not interested in a particular ID.
   *
   * Be aware that for clients that a compositor forks and execs and
   * then connects using socketpair(), this function will return the
   * credentials for the compositor.  The credentials for the socketpair
   * are set at creation time in the compositor.
   *
   * \memberof wl_client
   */
  WL_EXPORT void
  wl_client_get_credentials(struct wl_client *client,
  			  pid_t *pid, uid_t *uid, gid_t *gid)
  {
  	if (pid)
  		*pid = client->ucred.pid;
  	if (uid)
  		*uid = client->ucred.uid;
  	if (gid)
  		*gid = client->ucred.gid;
  }
  
  /** Look up an object in the client name space
   *
   * \param client The client object
   * \param id The object id
   * \return The object or NULL if there is not object for the given ID
   *
   * This looks up an object in the client object name space by its
   * object ID.
   *
   * \memberof wl_client
   */
  WL_EXPORT struct wl_resource *
  wl_client_get_object(struct wl_client *client, uint32_t id)
  {
  	return wl_map_lookup(&client->objects, id);
  }
  
  WL_EXPORT void
  wl_client_post_no_memory(struct wl_client *client)
  {
  	wl_resource_post_error(client->display_resource,
  			       WL_DISPLAY_ERROR_NO_MEMORY, "no memory");
  }
  
  WL_EXPORT void
  wl_resource_post_no_memory(struct wl_resource *resource)
  {
  	wl_resource_post_error(resource->client->display_resource,
  			       WL_DISPLAY_ERROR_NO_MEMORY, "no memory");
  }
  
  static void
  destroy_resource(void *element, void *data)
  {
  	struct wl_resource *resource = element;
  	struct wl_client *client = resource->client;
  	uint32_t flags;
  
  	wl_signal_emit(&resource->destroy_signal, resource);
  
  	flags = wl_map_lookup_flags(&client->objects, resource->object.id);
  	if (resource->destroy)
  		resource->destroy(resource);
  
  	if (!(flags & WL_MAP_ENTRY_LEGACY))
  		free(resource);
  }
  
  WL_EXPORT void
  wl_resource_destroy(struct wl_resource *resource)
  {
  	struct wl_client *client = resource->client;
  	uint32_t id;
  
  	id = resource->object.id;
  	destroy_resource(resource, NULL);
  
  	if (id < WL_SERVER_ID_START) {
  		if (client->display_resource) {
  			wl_resource_queue_event(client->display_resource,
  						WL_DISPLAY_DELETE_ID, id);
  		}
  		wl_map_insert_at(&client->objects, 0, id, NULL);
  	} else {
  		wl_map_remove(&client->objects, id);
  	}
  }
  
  WL_EXPORT uint32_t
  wl_resource_get_id(struct wl_resource *resource)
  {
  	return resource->object.id;
  }
  
  WL_EXPORT struct wl_list *
  wl_resource_get_link(struct wl_resource *resource)
  {
  	return &resource->link;
  }
  
  WL_EXPORT struct wl_resource *
  wl_resource_from_link(struct wl_list *link)
  {
  	struct wl_resource *resource;
  
  	return wl_container_of(link, resource, link);
  }
  
  WL_EXPORT struct wl_resource *
  wl_resource_find_for_client(struct wl_list *list, struct wl_client *client)
  {
  	struct wl_resource *resource;
  
  	if (client == NULL)
  		return NULL;
  
  	wl_list_for_each(resource, list, link) {
  		if (resource->client == client)
  			return resource;
  	}
  
  	return NULL;
  }
  
  WL_EXPORT struct wl_client *
  wl_resource_get_client(struct wl_resource *resource)
  {
  	return resource->client;
  }
  
  WL_EXPORT void
  wl_resource_set_user_data(struct wl_resource *resource, void *data)
  {
  	resource->data = data;
  }
  
  WL_EXPORT void *
  wl_resource_get_user_data(struct wl_resource *resource)
  {
  	return resource->data;
  }
  
  WL_EXPORT int
  wl_resource_get_version(struct wl_resource *resource)
  {
  	return resource->version;
  }
  
  WL_EXPORT void
  wl_resource_set_destructor(struct wl_resource *resource,
  			   wl_resource_destroy_func_t destroy)
  {
  	resource->destroy = destroy;
  }
  
  WL_EXPORT int
  wl_resource_instance_of(struct wl_resource *resource,
  			const struct wl_interface *interface,
  			const void *implementation)
  {
  	return wl_interface_equal(resource->object.interface, interface) &&
  		resource->object.implementation == implementation;
  }
  
  WL_EXPORT void
  wl_resource_add_destroy_listener(struct wl_resource *resource,
  				 struct wl_listener * listener)
  {
  	wl_signal_add(&resource->destroy_signal, listener);
  }
  
  WL_EXPORT struct wl_listener *
  wl_resource_get_destroy_listener(struct wl_resource *resource,
  				 wl_notify_func_t notify)
  {
  	return wl_signal_get(&resource->destroy_signal, notify);
  }
  
  WL_EXPORT void
  wl_client_add_destroy_listener(struct wl_client *client,
  			       struct wl_listener *listener)
  {
  	wl_signal_add(&client->destroy_signal, listener);
  }
  
  WL_EXPORT struct wl_listener *
  wl_client_get_destroy_listener(struct wl_client *client,
  			       wl_notify_func_t notify)
  {
  	return wl_signal_get(&client->destroy_signal, notify);
  }
  
  WL_EXPORT void
  wl_client_destroy(struct wl_client *client)
  {
  	uint32_t serial = 0;
  
  	wl_signal_emit(&client->destroy_signal, client);
  
  	wl_client_flush(client);
  	wl_map_for_each(&client->objects, destroy_resource, &serial);
  	wl_map_release(&client->objects);
  	wl_event_source_remove(client->source);
  	close(wl_connection_destroy(client->connection));
  	wl_list_remove(&client->link);
  	free(client);
  }
  
  static void
  registry_bind(struct wl_client *client,
  	      struct wl_resource *resource, uint32_t name,
  	      const char *interface, uint32_t version, uint32_t id)
  {
  	struct wl_global *global;
  	struct wl_display *display = resource->data;
  
  	wl_list_for_each(global, &display->global_list, link)
  		if (global->name == name)
  			break;
  
  	if (&global->link == &display->global_list)
  		wl_resource_post_error(resource,
  				       WL_DISPLAY_ERROR_INVALID_OBJECT,
  				       "invalid global %s (%d)", interface, name);
  	else if (global->version < version)
  		wl_resource_post_error(resource,
  				       WL_DISPLAY_ERROR_INVALID_OBJECT,
  				       "invalid version for global %s (%d): have %d, wanted %d",
  				       interface, name, global->version, version);
  	else
  		global->bind(client, global->data, version, id);
  }
  
  static const struct wl_registry_interface registry_interface = {
  	registry_bind
  };
  
  static void
  display_sync(struct wl_client *client,
  	     struct wl_resource *resource, uint32_t id)
  {
  	struct wl_resource *callback;
  	uint32_t serial;
  
  	callback = wl_resource_create(client, &wl_callback_interface, 1, id);
  	if (callback == NULL) {
  		wl_client_post_no_memory(client);
  		return;
  	}
  
  	serial = wl_display_get_serial(client->display);
  	wl_callback_send_done(callback, serial);
  	wl_resource_destroy(callback);
  }
  
  static void
  unbind_resource(struct wl_resource *resource)
  {
  	wl_list_remove(&resource->link);
  }
  
  static void
  display_get_registry(struct wl_client *client,
  		     struct wl_resource *resource, uint32_t id)
  {
  	struct wl_display *display = resource->data;
  	struct wl_resource *registry_resource;
  	struct wl_global *global;
  
  	registry_resource =
  		wl_resource_create(client, &wl_registry_interface, 1, id);
  	if (registry_resource == NULL) {
  		wl_client_post_no_memory(client);
  		return;
  	}
  
  	wl_resource_set_implementation(registry_resource,
  				       &registry_interface,
  				       display, unbind_resource);
  
  	wl_list_insert(&display->registry_resource_list,
  		       &registry_resource->link);
  
  	wl_list_for_each(global, &display->global_list, link)
  		wl_resource_post_event(registry_resource,
  				       WL_REGISTRY_GLOBAL,
  				       global->name,
  				       global->interface->name,
  				       global->version);
  }
  
  static const struct wl_display_interface display_interface = {
  	display_sync,
  	display_get_registry
  };
  
  static void
  destroy_client_display_resource(struct wl_resource *resource)
  {
  	resource->client->display_resource = NULL;
  }
  
  static int
  bind_display(struct wl_client *client, struct wl_display *display)
  {
  	client->display_resource =
  		wl_resource_create(client, &wl_display_interface, 1, 1);
  	if (client->display_resource == NULL) {
  		wl_client_post_no_memory(client);
  		return -1;
  	}
  
  	wl_resource_set_implementation(client->display_resource,
  				       &display_interface, display,
  				       destroy_client_display_resource);
  	return 0;
  }
  
  /** Create Wayland display object.
   *
   * \return The Wayland display object. Null if failed to create
   *
   * This creates the wl_display object.
   *
   * \memberof wl_display
   */
  WL_EXPORT struct wl_display *
  wl_display_create(void)
  {
  	struct wl_display *display;
  	const char *debug;
  
  	debug = getenv("WAYLAND_DEBUG");
  	if (debug && (strstr(debug, "server") || strstr(debug, "1")))
  		debug_server = 1;
  
  	display = malloc(sizeof *display);
  	if (display == NULL)
  		return NULL;
  
  	display->loop = wl_event_loop_create();
  	if (display->loop == NULL) {
  		free(display);
  		return NULL;
  	}
  
  	wl_list_init(&display->global_list);
  	wl_list_init(&display->socket_list);
  	wl_list_init(&display->client_list);
  	wl_list_init(&display->registry_resource_list);
  
  	wl_signal_init(&display->destroy_signal);
  
  	display->id = 1;
  	display->serial = 0;
  
  	wl_array_init(&display->additional_shm_formats);
  
  	return display;
  }
  
  static void
  wl_socket_destroy(struct wl_socket *s)
  {
  	if (s->source)
  		wl_event_source_remove(s->source);
  	if (s->addr.sun_path[0])
  		unlink(s->addr.sun_path);
  	if (s->fd >= 0)
  		close(s->fd);
  	if (s->lock_addr[0])
  		unlink(s->lock_addr);
  	if (s->fd_lock >= 0)
  		close(s->fd_lock);
  
  	free(s);
  }
  
  static struct wl_socket *
  wl_socket_alloc(void)
  {
  	struct wl_socket *s;
  
  	s = malloc(sizeof *s);
  	if (!s)
  		return NULL;
  
  	memset(s, 0, sizeof *s);
  	s->fd = -1;
  	s->fd_lock = -1;
  
  	return s;
  }
  
  /** Destroy Wayland display object.
   *
   * \param display The Wayland display object which should be destroyed.
   * \return None.
   *
   * This function emits the wl_display destroy signal, releases
   * all the sockets added to this display, free's all the globals associated
   * with this display, free's memory of additional shared memory formats and
   * destroy the display object.
   *
   * \sa wl_display_add_destroy_listener
   *
   * \memberof wl_display
   */
  WL_EXPORT void
  wl_display_destroy(struct wl_display *display)
  {
  	struct wl_socket *s, *next;
  	struct wl_global *global, *gnext;
  
  	wl_signal_emit(&display->destroy_signal, display);
  
  	wl_list_for_each_safe(s, next, &display->socket_list, link) {
  		wl_socket_destroy(s);
  	}
  	wl_event_loop_destroy(display->loop);
  
  	wl_list_for_each_safe(global, gnext, &display->global_list, link)
  		free(global);
  
  	wl_array_release(&display->additional_shm_formats);
  
  	free(display);
  }
  
  WL_EXPORT struct wl_global *
  wl_global_create(struct wl_display *display,
  		 const struct wl_interface *interface, int version,
  		 void *data, wl_global_bind_func_t bind)
  {
  	struct wl_global *global;
  	struct wl_resource *resource;
  
  	if (interface->version < version) {
  		wl_log("wl_global_create: implemented version higher "
  		       "than interface version%m\n");
  		return NULL;
  	}
  
  	global = malloc(sizeof *global);
  	if (global == NULL)
  		return NULL;
  
  	global->display = display;
  	global->name = display->id++;
  	global->interface = interface;
  	global->version = version;
  	global->data = data;
  	global->bind = bind;
  	wl_list_insert(display->global_list.prev, &global->link);
  
  	wl_list_for_each(resource, &display->registry_resource_list, link)
  		wl_resource_post_event(resource,
  				       WL_REGISTRY_GLOBAL,
  				       global->name,
  				       global->interface->name,
  				       global->version);
  
  	return global;
  }
  
  WL_EXPORT void
  wl_global_destroy(struct wl_global *global)
  {
  	struct wl_display *display = global->display;
  	struct wl_resource *resource;
  
  	wl_list_for_each(resource, &display->registry_resource_list, link)
  		wl_resource_post_event(resource, WL_REGISTRY_GLOBAL_REMOVE,
  				       global->name);
  	wl_list_remove(&global->link);
  	free(global);
  }
  
  /** Get the current serial number
   *
   * \param display The display object
   *
   * This function returns the most recent serial number, but does not
   * increment it.
   *
   * \memberof wl_display
   */
  WL_EXPORT uint32_t
  wl_display_get_serial(struct wl_display *display)
  {
  	return display->serial;
  }
  
  /** Get the next serial number
   *
   * \param display The display object
   *
   * This function increments the display serial number and returns the
   * new value.
   *
   * \memberof wl_display
   */
  WL_EXPORT uint32_t
  wl_display_next_serial(struct wl_display *display)
  {
  	display->serial++;
  
  	return display->serial;
  }
  
  WL_EXPORT struct wl_event_loop *
  wl_display_get_event_loop(struct wl_display *display)
  {
  	return display->loop;
  }
  
  WL_EXPORT void
  wl_display_terminate(struct wl_display *display)
  {
  	display->run = 0;
  }
  
  WL_EXPORT void
  wl_display_run(struct wl_display *display)
  {
  	display->run = 1;
  
  	while (display->run) {
  		wl_display_flush_clients(display);
  		wl_event_loop_dispatch(display->loop, -1);
  	}
  }
  
  WL_EXPORT void
  wl_display_flush_clients(struct wl_display *display)
  {
  	struct wl_client *client, *next;
  	int ret;
  
  	wl_list_for_each_safe(client, next, &display->client_list, link) {
  		ret = wl_connection_flush(client->connection);
  		if (ret < 0 && errno == EAGAIN) {
  			wl_event_source_fd_update(client->source,
  						  WL_EVENT_WRITABLE |
  						  WL_EVENT_READABLE);
  		} else if (ret < 0) {
  			wl_client_destroy(client);
  		}
  	}
  }
  
  static int
  socket_data(int fd, uint32_t mask, void *data)
  {
  	struct wl_display *display = data;
  	struct sockaddr_un name;
  	socklen_t length;
  	int client_fd;
  
  	length = sizeof name;
  	client_fd = wl_os_accept_cloexec(fd, (struct sockaddr *) &name,
  					 &length);
  	if (client_fd < 0)
  		wl_log("failed to accept: %m\n");
  	else
  		if (!wl_client_create(display, client_fd))
  			close(client_fd);
  
  	return 1;
  }
  
  static int
  wl_socket_lock(struct wl_socket *socket)
  {
  	struct stat socket_stat;
  
  	snprintf(socket->lock_addr, sizeof socket->lock_addr,
  		 "%s%s", socket->addr.sun_path, LOCK_SUFFIX);
  
  	socket->fd_lock = open(socket->lock_addr, O_CREAT | O_CLOEXEC,
  			       (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP));
  
  	if (socket->fd_lock < 0) {
  		wl_log("unable to open lockfile %s check permissions\n",
  			socket->lock_addr);
  		goto err;
  	}
  
  	if (flock(socket->fd_lock, LOCK_EX | LOCK_NB) < 0) {
  		wl_log("unable to lock lockfile %s, maybe another compositor is running\n",
  			socket->lock_addr);
  		goto err_fd;
  	}
  
  	if (stat(socket->addr.sun_path, &socket_stat) < 0 ) {
  		if (errno != ENOENT) {
  			wl_log("did not manage to stat file %s\n",
  				socket->addr.sun_path);
  			goto err_fd;
  		}
  	} else if (socket_stat.st_mode & S_IWUSR ||
  		   socket_stat.st_mode & S_IWGRP) {
  		unlink(socket->addr.sun_path);
  	}
  
  	return 0;
  err_fd:
  	close(socket->fd_lock);
  	socket->fd_lock = -1;
  err:
  	*socket->lock_addr = 0;
  	/* we did not set this value here, but without lock the
  	 * socket won't be created anyway. This prevents the
  	 * wl_socket_destroy from unlinking already existing socket
  	 * created by other compositor */
  	*socket->addr.sun_path = 0;
  
  	return -1;
  }
  
  static int
  wl_socket_init_for_display_name(struct wl_socket *s, const char *name)
  {
  	int name_size;
  	const char *runtime_dir;
  
  	runtime_dir = getenv("XDG_RUNTIME_DIR");
  	if (!runtime_dir) {
  		wl_log("error: XDG_RUNTIME_DIR not set in the environment\n");
  
  		/* to prevent programs reporting
  		 * "failed to add socket: Success" */
  		errno = ENOENT;
  		return -1;
  	}
  
  	s->addr.sun_family = AF_LOCAL;
  	name_size = snprintf(s->addr.sun_path, sizeof s->addr.sun_path,
  			     "%s/%s", runtime_dir, name) + 1;
  
  	s->display_name = (s->addr.sun_path + name_size - 1) - strlen(name);
  
  	assert(name_size > 0);
  	if (name_size > (int)sizeof s->addr.sun_path) {
  		wl_log("error: socket path \"%s/%s\" plus null terminator"
  		       " exceeds 108 bytes\n", runtime_dir, name);
  		*s->addr.sun_path = 0;
  		/* to prevent programs reporting
  		 * "failed to add socket: Success" */
  		errno = ENAMETOOLONG;
  		return -1;
  	}
  
  	return 0;
  }
  
  static int
  _wl_display_add_socket(struct wl_display *display, struct wl_socket *s)
  {
  	socklen_t size;
  
  	s->fd = wl_os_socket_cloexec(PF_LOCAL, SOCK_STREAM, 0);
  	if (s->fd < 0) {
  		return -1;
  	}
  
  	size = offsetof (struct sockaddr_un, sun_path) + strlen(s->addr.sun_path);
  	if (bind(s->fd, (struct sockaddr *) &s->addr, size) < 0) {
  		wl_log("bind() failed with error: %m\n");
  		return -1;
  	}
  
  	if (listen(s->fd, 128) < 0) {
  		wl_log("listen() failed with error: %m\n");
  		return -1;
  	}
  
  	s->source = wl_event_loop_add_fd(display->loop, s->fd,
  					 WL_EVENT_READABLE,
  					 socket_data, display);
  	if (s->source == NULL) {
  		return -1;
  	}
  
  	wl_list_insert(display->socket_list.prev, &s->link);
  	return 0;
  }
  
  WL_EXPORT const char *
  wl_display_add_socket_auto(struct wl_display *display)
  {
  	struct wl_socket *s;
  	int displayno = 0;
  	char display_name[16] = "";
  
  	/* A reasonable number of maximum default sockets. If
  	 * you need more than this, use the explicit add_socket API. */
  	const int MAX_DISPLAYNO = 32;
  
  	s = wl_socket_alloc();
  	if (s == NULL)
  		return NULL;
  
  	do {
  		snprintf(display_name, sizeof display_name, "wayland-%d", displayno);
  		if (wl_socket_init_for_display_name(s, display_name) < 0) {
  			wl_socket_destroy(s);
  			return NULL;
  		}
  
  		if (wl_socket_lock(s) < 0)
  			continue;
  
  		if (_wl_display_add_socket(display, s) < 0) {
  			wl_socket_destroy(s);
  			return NULL;
  		}
  
  		return s->display_name;
  	} while (displayno++ < MAX_DISPLAYNO);
  
  	/* Ran out of display names. */
  	wl_socket_destroy(s);
  	errno = EINVAL;
  	return NULL;
  }
  
  /** Add a socket to Wayland display for the clients to connect.
   *
   * \param display Wayland display to which the socket should be added.
   * \param name Name of the Unix socket.
   * \return 0 if success. -1 if failed.
   *
   * This adds a Unix socket to Wayland display which can be used by clients to
   * connect to Wayland display.
   *
   * If NULL is passed as name, then it would look for WAYLAND_DISPLAY env
   * variable for the socket name. If WAYLAND_DISPLAY is not set, then default
   * wayland-0 is used.
   *
   * The Unix socket will be created in the directory pointed to by environment
   * variable XDG_RUNTIME_DIR. If XDG_RUNTIME_DIR is not set, then this function
   * fails and returns -1.
   *
   * The length of socket path, i.e., the path set in XDG_RUNTIME_DIR and the
   * socket name, must not exceed the maxium length of a Unix socket path.
   * The function also fails if the user do not have write permission in the
   * XDG_RUNTIME_DIR path or if the socket name is already in use.
   *
   * \memberof wl_display
   */
  WL_EXPORT int
  wl_display_add_socket(struct wl_display *display, const char *name)
  {
  	struct wl_socket *s;
  
  	s = wl_socket_alloc();
  	if (s == NULL)
  		return -1;
  
  	if (name == NULL)
  		name = getenv("WAYLAND_DISPLAY");
  	if (name == NULL)
  		name = "wayland-0";
  
  	if (wl_socket_init_for_display_name(s, name) < 0) {
  		wl_socket_destroy(s);
  		return -1;
  	}
  
  	if (wl_socket_lock(s) < 0) {
  		wl_socket_destroy(s);
  		return -1;
  	}
  
  	if (_wl_display_add_socket(display, s) < 0) {
  		wl_socket_destroy(s);
  		return -1;
  	}
  
  	return 0;
  }
  
  WL_EXPORT void
  wl_display_add_destroy_listener(struct wl_display *display,
  				struct wl_listener *listener)
  {
  	wl_signal_add(&display->destroy_signal, listener);
  }
  
  WL_EXPORT struct wl_listener *
  wl_display_get_destroy_listener(struct wl_display *display,
  				wl_notify_func_t notify)
  {
  	return wl_signal_get(&display->destroy_signal, notify);
  }
  
  WL_EXPORT void
  wl_resource_set_implementation(struct wl_resource *resource,
  			       const void *implementation,
  			       void *data, wl_resource_destroy_func_t destroy)
  {
  	resource->object.implementation = implementation;
  	resource->data = data;
  	resource->destroy = destroy;
  	resource->dispatcher = NULL;
  }
  
  WL_EXPORT void
  wl_resource_set_dispatcher(struct wl_resource *resource,
  			   wl_dispatcher_func_t dispatcher,
  			   const void *implementation,
  			   void *data, wl_resource_destroy_func_t destroy)
  {
  	resource->dispatcher = dispatcher;
  	resource->object.implementation = implementation;
  	resource->data = data;
  	resource->destroy = destroy;
  }
  
  WL_EXPORT struct wl_resource *
  wl_resource_create(struct wl_client *client,
  		   const struct wl_interface *interface,
  		   int version, uint32_t id)
  {
  	struct wl_resource *resource;
  
  	resource = malloc(sizeof *resource);
  	if (resource == NULL)
  		return NULL;
  
  	if (id == 0)
  		id = wl_map_insert_new(&client->objects, 0, NULL);
  
  	resource->object.id = id;
  	resource->object.interface = interface;
  	resource->object.implementation = NULL;
  
  	wl_signal_init(&resource->destroy_signal);
  
  	resource->destroy = NULL;
  	resource->client = client;
  	resource->data = NULL;
  	resource->version = version;
  	resource->dispatcher = NULL;
  
  	if (wl_map_insert_at(&client->objects, 0, id, resource) < 0) {
  		wl_resource_post_error(client->display_resource,
  				       WL_DISPLAY_ERROR_INVALID_OBJECT,
  				       "invalid new id %d", id);
  		free(resource);
  		return NULL;
  	}
  
  	return resource;
  }
  
  WL_EXPORT void
  wl_log_set_handler_server(wl_log_func_t handler)
  {
  	wl_log_handler = handler;
  }
  
  /** Add support for a wl_shm pixel format
   *
   * \param display The display object
   * \param format The wl_shm pixel format to advertise
   * \return A pointer to the wl_shm format that was added to the list
   * or NULL if adding it to the list failed.
   *
   * Add the specified wl_shm format to the list of formats the wl_shm
   * object advertises when a client binds to it.  Adding a format to
   * the list means that clients will know that the compositor supports
   * this format and may use it for creating wl_shm buffers.  The
   * compositor must be able to handle the pixel format when a client
   * requests it.
   *
   * The compositor by default supports WL_SHM_FORMAT_ARGB8888 and
   * WL_SHM_FORMAT_XRGB8888.
   *
   * \memberof wl_display
   */
  WL_EXPORT uint32_t *
  wl_display_add_shm_format(struct wl_display *display, uint32_t format)
  {
  	uint32_t *p = NULL;
  
  	p = wl_array_add(&display->additional_shm_formats, sizeof *p);
  
  	if (p != NULL)
  		*p = format;
  	return p;
  }
  
  /**
   * Get list of additional wl_shm pixel formats
   *
   * \param display The display object
   *
   * This function returns the list of addition wl_shm pixel formats
   * that the compositor supports.  WL_SHM_FORMAT_ARGB8888 and
   * WL_SHM_FORMAT_XRGB8888 are always supported and not included in the
   * array, but all formats added through wl_display_add_shm_format()
   * will be in the array.
   *
   * \sa wl_display_add_shm_format()
   *
   * \memberof wl_display
   */
  struct wl_array *
  wl_display_get_additional_shm_formats(struct wl_display *display)
  {
  	return &display->additional_shm_formats;
  }
  
  /** \cond */ /* Deprecated functions below. */
  
  uint32_t
  wl_client_add_resource(struct wl_client *client,
  		       struct wl_resource *resource) WL_DEPRECATED;
  
  WL_EXPORT uint32_t
  wl_client_add_resource(struct wl_client *client,
  		       struct wl_resource *resource)
  {
  	if (resource->object.id == 0) {
  		resource->object.id =
  			wl_map_insert_new(&client->objects,
  					  WL_MAP_ENTRY_LEGACY, resource);
  	} else if (wl_map_insert_at(&client->objects, WL_MAP_ENTRY_LEGACY,
  				  resource->object.id, resource) < 0) {
  		wl_resource_post_error(client->display_resource,
  				       WL_DISPLAY_ERROR_INVALID_OBJECT,
  				       "invalid new id %d",
  				       resource->object.id);
  		return 0;
  	}
  
  	resource->client = client;
  	wl_signal_init(&resource->destroy_signal);
  
  	return resource->object.id;
  }
  
  struct wl_resource *
  wl_client_add_object(struct wl_client *client,
  		     const struct wl_interface *interface,
  		     const void *implementation,
  		     uint32_t id, void *data) WL_DEPRECATED;
  
  WL_EXPORT struct wl_resource *
  wl_client_add_object(struct wl_client *client,
  		     const struct wl_interface *interface,
  		     const void *implementation, uint32_t id, void *data)
  {
  	struct wl_resource *resource;
  
  	resource = wl_resource_create(client, interface, -1, id);
  	if (resource == NULL)
  		wl_client_post_no_memory(client);
  	else
  		wl_resource_set_implementation(resource,
  					       implementation, data, NULL);
  
  	return resource;
  }
  
  struct wl_resource *
  wl_client_new_object(struct wl_client *client,
  		     const struct wl_interface *interface,
  		     const void *implementation, void *data) WL_DEPRECATED;
  
  WL_EXPORT struct wl_resource *
  wl_client_new_object(struct wl_client *client,
  		     const struct wl_interface *interface,
  		     const void *implementation, void *data)
  {
  	struct wl_resource *resource;
  
  	resource = wl_resource_create(client, interface, -1, 0);
  	if (resource == NULL)
  		wl_client_post_no_memory(client);
  	else
  		wl_resource_set_implementation(resource,
  					       implementation, data, NULL);
  
  	return resource;
  }
  
  struct wl_global *
  wl_display_add_global(struct wl_display *display,
  		      const struct wl_interface *interface,
  		      void *data, wl_global_bind_func_t bind) WL_DEPRECATED;
  
  WL_EXPORT struct wl_global *
  wl_display_add_global(struct wl_display *display,
  		      const struct wl_interface *interface,
  		      void *data, wl_global_bind_func_t bind)
  {
  	return wl_global_create(display, interface, interface->version, data, bind);
  }
  
  void
  wl_display_remove_global(struct wl_display *display,
  			 struct wl_global *global) WL_DEPRECATED;
  
  WL_EXPORT void
  wl_display_remove_global(struct wl_display *display, struct wl_global *global)
  {
  	wl_global_destroy(global);
  }
  
  /** \endcond */
  
  /* Functions at the end of this file are deprecated.  Instead of adding new
   * code here, add it before the comment above that states:
   * Deprecated functions below.
   */
  