gio/gunixfdmessage.c - third_party/glib - Git at Google

 /* GIO - GLib Input, Output and Streaming Library
  *
  * Copyright © 2009 Codethink Limited
  *
  * SPDX-License-Identifier: LGPL-2.1-or-later
  *
  * 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 2.1 of the License, or (at your option) any later version.
  *
  * See the included COPYING file for more information.
  *
  * Authors: Ryan Lortie <desrt@desrt.ca>
  */

 /**
  * GUnixFDMessage:
  *
  * This [class@Gio.SocketControlMessage] contains a [class@Gio.UnixFDList].
  * It may be sent using [method@Gio.Socket.send_message] and received using
  * [method@Gio.Socket.receive_message] over UNIX sockets (ie: sockets in the
  * `G_SOCKET_FAMILY_UNIX` family). The file descriptors are copied
  * between processes by the kernel.
  *
  * For an easier way to send and receive file descriptors over
  * stream-oriented UNIX sockets, see [method@Gio.UnixConnection.send_fd] and
  * [method@Gio.UnixConnection.receive_fd].
  *
  * Note that `<gio/gunixfdmessage.h>` belongs to the UNIX-specific GIO
  * interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config
  * file or the `GioUnix-2.0` GIR namespace when using it.
  */

 #include "config.h"

 #include <unistd.h>
 #include <string.h>
 #include <fcntl.h>
 #include <errno.h>

 #include "gunixfdmessage.h"
 #include "gunixfdlist.h"
 #include "gnetworking.h"
 #include "gioerror.h"

 struct _GUnixFDMessagePrivate
 {
   GUnixFDList *list;
 };

 G_DEFINE_TYPE_WITH_PRIVATE (GUnixFDMessage, g_unix_fd_message, G_TYPE_SOCKET_CONTROL_MESSAGE)

 static gsize
 g_unix_fd_message_get_size (GSocketControlMessage *message)
 {
   GUnixFDMessage *fd_message = G_UNIX_FD_MESSAGE (message);

   return g_unix_fd_list_get_length (fd_message->priv->list) * sizeof (gint);
 }

 static int
 g_unix_fd_message_get_level (GSocketControlMessage *message)
 {
   return SOL_SOCKET;
 }

 static int
 g_unix_fd_message_get_msg_type (GSocketControlMessage *message)
 {
   return SCM_RIGHTS;
 }

 static GSocketControlMessage *
 g_unix_fd_message_deserialize (int      level,
 			       int      type,
 			       gsize    size,
 			       gpointer data)
 {
   GSocketControlMessage *message;
   GUnixFDList *list;
   gint n, s, i;
   gint *fds;

   if (level != SOL_SOCKET ||
       type != SCM_RIGHTS)
     return NULL;

   if (size % 4 > 0)
     {
       g_warning ("Kernel returned non-integral number of fds");
       return NULL;
     }

   fds = data;
   n = size / sizeof (gint);

   /* Note we probably handled this in gsocket.c already if we're on
    * Linux and have MSG_CMSG_CLOEXEC, but this code remains as a fallback
    * in case the kernel is too old for MSG_CMSG_CLOEXEC.
    */
   for (i = 0; i < n; i++)
     {
       int errsv;

       do
         {
           s = fcntl (fds[i], F_SETFD, FD_CLOEXEC);
           errsv = errno;
         }
       while (s < 0 && errsv == EINTR);

       if (s < 0)
         {
           g_warning ("Error setting close-on-exec flag on incoming fd: %s",
                      g_strerror (errsv));
           return NULL;
         }
     }

   list = g_unix_fd_list_new_from_array (fds, n);
   message = g_unix_fd_message_new_with_fd_list (list);
   g_object_unref (list);

   return message;
 }

 static void
 g_unix_fd_message_serialize (GSocketControlMessage *message,
 			     gpointer               data)
 {
   GUnixFDMessage *fd_message = G_UNIX_FD_MESSAGE (message);
   const gint *fds;
   gint n_fds;

   fds = g_unix_fd_list_peek_fds (fd_message->priv->list, &n_fds);
   memcpy (data, fds, sizeof (gint) * n_fds);
 }

 static void
 g_unix_fd_message_set_property (GObject *object, guint prop_id,
                                 const GValue *value, GParamSpec *pspec)
 {
   GUnixFDMessage *message = G_UNIX_FD_MESSAGE (object);

   g_assert (message->priv->list == NULL);
   g_assert_cmpint (prop_id, ==, 1);

   message->priv->list = g_value_dup_object (value);

   if (message->priv->list == NULL)
     message->priv->list = g_unix_fd_list_new ();
 }

 /**
  * g_unix_fd_message_get_fd_list:
  * @message: a #GUnixFDMessage
  *
  * Gets the #GUnixFDList contained in @message.  This function does not
  * return a reference to the caller, but the returned list is valid for
  * the lifetime of @message.
  *
  * Returns: (transfer none): the #GUnixFDList from @message
  *
  * Since: 2.24
  **/
 GUnixFDList *
 g_unix_fd_message_get_fd_list (GUnixFDMessage *message)
 {
   return message->priv->list;
 }

 static void
 g_unix_fd_message_get_property (GObject *object, guint prop_id,
                                 GValue *value, GParamSpec *pspec)
 {
   GUnixFDMessage *message = G_UNIX_FD_MESSAGE (object);

   g_assert_cmpint (prop_id, ==, 1);

   g_value_set_object (value, g_unix_fd_message_get_fd_list (message));
 }

 static void
 g_unix_fd_message_init (GUnixFDMessage *message)
 {
   message->priv = g_unix_fd_message_get_instance_private (message);
 }

 static void
 g_unix_fd_message_finalize (GObject *object)
 {
   GUnixFDMessage *message = G_UNIX_FD_MESSAGE (object);

   g_object_unref (message->priv->list);

   G_OBJECT_CLASS (g_unix_fd_message_parent_class)
     ->finalize (object);
 }

 static void
 g_unix_fd_message_class_init (GUnixFDMessageClass *class)
 {
   GSocketControlMessageClass *scm_class = G_SOCKET_CONTROL_MESSAGE_CLASS (class);
   GObjectClass *object_class = G_OBJECT_CLASS (class);

   scm_class->get_size = g_unix_fd_message_get_size;
   scm_class->get_level = g_unix_fd_message_get_level;
   scm_class->get_type = g_unix_fd_message_get_msg_type;
   scm_class->serialize = g_unix_fd_message_serialize;
   scm_class->deserialize = g_unix_fd_message_deserialize;
   object_class->finalize = g_unix_fd_message_finalize;
   object_class->set_property = g_unix_fd_message_set_property;
   object_class->get_property = g_unix_fd_message_get_property;

   /**
    * GUnixFDMessage:fd-list:
    *
    * The [class@Gio.UnixFDList] object to send with the message.
    *
    * Since: 2.22
    */
   g_object_class_install_property (object_class, 1,
     g_param_spec_object ("fd-list", NULL, NULL,
                          G_TYPE_UNIX_FD_LIST, G_PARAM_STATIC_STRINGS |
                          G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
 }

 /**
  * g_unix_fd_message_new:
  *
  * Creates a new #GUnixFDMessage containing an empty file descriptor
  * list.
  *
  * Returns: a new #GUnixFDMessage
  *
  * Since: 2.22
  **/
 GSocketControlMessage *
 g_unix_fd_message_new (void)
 {
   return g_object_new (G_TYPE_UNIX_FD_MESSAGE, NULL);
 }

 /**
  * g_unix_fd_message_new_with_fd_list:
  * @fd_list: a #GUnixFDList
  *
  * Creates a new #GUnixFDMessage containing @list.
  *
  * Returns: a new #GUnixFDMessage
  *
  * Since: 2.24
  **/
 GSocketControlMessage *
 g_unix_fd_message_new_with_fd_list (GUnixFDList *fd_list)
 {
   return g_object_new (G_TYPE_UNIX_FD_MESSAGE,
                        "fd-list", fd_list,
                        NULL);
 }

 /**
  * g_unix_fd_message_steal_fds:
  * @message: a #GUnixFDMessage
  * @length: (out) (optional): pointer to the length of the returned
  *     array, or %NULL
  *
  * Returns the array of file descriptors that is contained in this
  * object.
  *
  * After this call, the descriptors are no longer contained in
  * @message. Further calls will return an empty list (unless more
  * descriptors have been added).
  *
  * The return result of this function must be freed with g_free().
  * The caller is also responsible for closing all of the file
  * descriptors.
  *
  * If @length is non-%NULL then it is set to the number of file
  * descriptors in the returned array. The returned array is also
  * terminated with -1.
  *
  * This function never returns %NULL. In case there are no file
  * descriptors contained in @message, an empty array is returned.
  *
  * Returns: (array length=length) (transfer full): an array of file
  *     descriptors
  *
  * Since: 2.22
  **/
 gint *
 g_unix_fd_message_steal_fds (GUnixFDMessage *message,
                              gint           *length)
 {
   g_return_val_if_fail (G_UNIX_FD_MESSAGE (message), NULL);

   return g_unix_fd_list_steal_fds (message->priv->list, length);
 }

 /**
  * g_unix_fd_message_append_fd:
  * @message: a #GUnixFDMessage
  * @fd: a valid open file descriptor
  * @error: a #GError pointer
  *
  * Adds a file descriptor to @message.
  *
  * The file descriptor is duplicated using dup(). You keep your copy
  * of the descriptor and the copy contained in @message will be closed
  * when @message is finalized.
  *
  * A possible cause of failure is exceeding the per-process or
  * system-wide file descriptor limit.
  *
  * Returns: %TRUE in case of success, else %FALSE (and @error is set)
  *
  * Since: 2.22
  **/
 gboolean
 g_unix_fd_message_append_fd (GUnixFDMessage  *message,
                              gint             fd,
                              GError         **error)
 {
   g_return_val_if_fail (G_UNIX_FD_MESSAGE (message), FALSE);

   return g_unix_fd_list_append (message->priv->list, fd, error) >= 0;
 }
	/* GIO - GLib Input, Output and Streaming Library
	*
	* Copyright © 2009 Codethink Limited
	*
	* SPDX-License-Identifier: LGPL-2.1-or-later
	*
	* 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 2.1 of the License, or (at your option) any later version.
	*
	* See the included COPYING file for more information.
	*
	* Authors: Ryan Lortie <desrt@desrt.ca>
	*/

	/**
	* GUnixFDMessage:
	*
	* This [class@Gio.SocketControlMessage] contains a [class@Gio.UnixFDList].
	* It may be sent using [method@Gio.Socket.send_message] and received using
	* [method@Gio.Socket.receive_message] over UNIX sockets (ie: sockets in the
	* `G_SOCKET_FAMILY_UNIX` family). The file descriptors are copied
	* between processes by the kernel.
	*
	* For an easier way to send and receive file descriptors over
	* stream-oriented UNIX sockets, see [method@Gio.UnixConnection.send_fd] and
	* [method@Gio.UnixConnection.receive_fd].
	*
	* Note that `<gio/gunixfdmessage.h>` belongs to the UNIX-specific GIO
	* interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config
	* file or the `GioUnix-2.0` GIR namespace when using it.
	*/

	#include "config.h"

	#include <unistd.h>
	#include <string.h>
	#include <fcntl.h>
	#include <errno.h>

	#include "gunixfdmessage.h"
	#include "gunixfdlist.h"
	#include "gnetworking.h"
	#include "gioerror.h"

	struct _GUnixFDMessagePrivate
	{
	GUnixFDList *list;
	};

	G_DEFINE_TYPE_WITH_PRIVATE (GUnixFDMessage, g_unix_fd_message, G_TYPE_SOCKET_CONTROL_MESSAGE)

	static gsize
	g_unix_fd_message_get_size (GSocketControlMessage *message)
	{
	GUnixFDMessage *fd_message = G_UNIX_FD_MESSAGE (message);

	return g_unix_fd_list_get_length (fd_message->priv->list) * sizeof (gint);
	}

	static int
	g_unix_fd_message_get_level (GSocketControlMessage *message)
	{
	return SOL_SOCKET;
	}

	static int
	g_unix_fd_message_get_msg_type (GSocketControlMessage *message)
	{
	return SCM_RIGHTS;
	}

	static GSocketControlMessage *
	g_unix_fd_message_deserialize (int level,
	int type,
	gsize size,
	gpointer data)
	{
	GSocketControlMessage *message;
	GUnixFDList *list;
	gint n, s, i;
	gint *fds;

	if (level != SOL_SOCKET \|\|
	type != SCM_RIGHTS)
	return NULL;

	if (size % 4 > 0)
	{
	g_warning ("Kernel returned non-integral number of fds");
	return NULL;
	}

	fds = data;
	n = size / sizeof (gint);

	/* Note we probably handled this in gsocket.c already if we're on
	* Linux and have MSG_CMSG_CLOEXEC, but this code remains as a fallback
	* in case the kernel is too old for MSG_CMSG_CLOEXEC.
	*/
	for (i = 0; i < n; i++)
	{
	int errsv;

	do
	{
	s = fcntl (fds[i], F_SETFD, FD_CLOEXEC);
	errsv = errno;
	}
	while (s < 0 && errsv == EINTR);

	if (s < 0)
	{
	g_warning ("Error setting close-on-exec flag on incoming fd: %s",
	g_strerror (errsv));
	return NULL;
	}
	}

	list = g_unix_fd_list_new_from_array (fds, n);
	message = g_unix_fd_message_new_with_fd_list (list);
	g_object_unref (list);

	return message;
	}

	static void
	g_unix_fd_message_serialize (GSocketControlMessage *message,
	gpointer data)
	{
	GUnixFDMessage *fd_message = G_UNIX_FD_MESSAGE (message);
	const gint *fds;
	gint n_fds;

	fds = g_unix_fd_list_peek_fds (fd_message->priv->list, &n_fds);
	memcpy (data, fds, sizeof (gint) * n_fds);
	}

	static void
	g_unix_fd_message_set_property (GObject *object, guint prop_id,
	const GValue value, GParamSpec pspec)
	{
	GUnixFDMessage *message = G_UNIX_FD_MESSAGE (object);

	g_assert (message->priv->list == NULL);
	g_assert_cmpint (prop_id, ==, 1);

	message->priv->list = g_value_dup_object (value);

	if (message->priv->list == NULL)
	message->priv->list = g_unix_fd_list_new ();
	}

	/**
	* g_unix_fd_message_get_fd_list:
	* @message: a #GUnixFDMessage
	*
	* Gets the #GUnixFDList contained in @message. This function does not
	* return a reference to the caller, but the returned list is valid for
	* the lifetime of @message.
	*
	* Returns: (transfer none): the #GUnixFDList from @message
	*
	* Since: 2.24
	**/
	GUnixFDList *
	g_unix_fd_message_get_fd_list (GUnixFDMessage *message)
	{
	return message->priv->list;
	}

	static void
	g_unix_fd_message_get_property (GObject *object, guint prop_id,
	GValue value, GParamSpec pspec)
	{
	GUnixFDMessage *message = G_UNIX_FD_MESSAGE (object);

	g_assert_cmpint (prop_id, ==, 1);

	g_value_set_object (value, g_unix_fd_message_get_fd_list (message));
	}

	static void
	g_unix_fd_message_init (GUnixFDMessage *message)
	{
	message->priv = g_unix_fd_message_get_instance_private (message);
	}

	static void
	g_unix_fd_message_finalize (GObject *object)
	{
	GUnixFDMessage *message = G_UNIX_FD_MESSAGE (object);

	g_object_unref (message->priv->list);

	G_OBJECT_CLASS (g_unix_fd_message_parent_class)
	->finalize (object);
	}

	static void
	g_unix_fd_message_class_init (GUnixFDMessageClass *class)
	{
	GSocketControlMessageClass *scm_class = G_SOCKET_CONTROL_MESSAGE_CLASS (class);
	GObjectClass *object_class = G_OBJECT_CLASS (class);

	scm_class->get_size = g_unix_fd_message_get_size;
	scm_class->get_level = g_unix_fd_message_get_level;
	scm_class->get_type = g_unix_fd_message_get_msg_type;
	scm_class->serialize = g_unix_fd_message_serialize;
	scm_class->deserialize = g_unix_fd_message_deserialize;
	object_class->finalize = g_unix_fd_message_finalize;
	object_class->set_property = g_unix_fd_message_set_property;
	object_class->get_property = g_unix_fd_message_get_property;

	/**
	* GUnixFDMessage:fd-list:
	*
	* The [class@Gio.UnixFDList] object to send with the message.
	*
	* Since: 2.22
	*/
	g_object_class_install_property (object_class, 1,
	g_param_spec_object ("fd-list", NULL, NULL,
	G_TYPE_UNIX_FD_LIST, G_PARAM_STATIC_STRINGS \|
	G_PARAM_READWRITE \| G_PARAM_CONSTRUCT_ONLY));
	}

	/**
	* g_unix_fd_message_new:
	*
	* Creates a new #GUnixFDMessage containing an empty file descriptor
	* list.
	*
	* Returns: a new #GUnixFDMessage
	*
	* Since: 2.22
	**/
	GSocketControlMessage *
	g_unix_fd_message_new (void)
	{
	return g_object_new (G_TYPE_UNIX_FD_MESSAGE, NULL);
	}

	/**
	* g_unix_fd_message_new_with_fd_list:
	* @fd_list: a #GUnixFDList
	*
	* Creates a new #GUnixFDMessage containing @list.
	*
	* Returns: a new #GUnixFDMessage
	*
	* Since: 2.24
	**/
	GSocketControlMessage *
	g_unix_fd_message_new_with_fd_list (GUnixFDList *fd_list)
	{
	return g_object_new (G_TYPE_UNIX_FD_MESSAGE,
	"fd-list", fd_list,
	NULL);
	}

	/**
	* g_unix_fd_message_steal_fds:
	* @message: a #GUnixFDMessage
	* @length: (out) (optional): pointer to the length of the returned
	* array, or %NULL
	*
	* Returns the array of file descriptors that is contained in this
	* object.
	*
	* After this call, the descriptors are no longer contained in
	* @message. Further calls will return an empty list (unless more
	* descriptors have been added).
	*
	* The return result of this function must be freed with g_free().
	* The caller is also responsible for closing all of the file
	* descriptors.
	*
	* If @length is non-%NULL then it is set to the number of file
	* descriptors in the returned array. The returned array is also
	* terminated with -1.
	*
	* This function never returns %NULL. In case there are no file
	* descriptors contained in @message, an empty array is returned.
	*
	* Returns: (array length=length) (transfer full): an array of file
	* descriptors
	*
	* Since: 2.22
	**/
	gint *
	g_unix_fd_message_steal_fds (GUnixFDMessage *message,
	gint *length)
	{
	g_return_val_if_fail (G_UNIX_FD_MESSAGE (message), NULL);

	return g_unix_fd_list_steal_fds (message->priv->list, length);
	}

	/**
	* g_unix_fd_message_append_fd:
	* @message: a #GUnixFDMessage
	* @fd: a valid open file descriptor
	* @error: a #GError pointer
	*
	* Adds a file descriptor to @message.
	*
	* The file descriptor is duplicated using dup(). You keep your copy
	* of the descriptor and the copy contained in @message will be closed
	* when @message is finalized.
	*
	* A possible cause of failure is exceeding the per-process or
	* system-wide file descriptor limit.
	*
	* Returns: %TRUE in case of success, else %FALSE (and @error is set)
	*
	* Since: 2.22
	**/
	gboolean
	g_unix_fd_message_append_fd (GUnixFDMessage *message,
	gint fd,
	GError **error)
	{
	g_return_val_if_fail (G_UNIX_FD_MESSAGE (message), FALSE);

	return g_unix_fd_list_append (message->priv->list, fd, error) >= 0;
	}