GUnixSocketAddress: handle abstract sockets with non-0-padded names

There are apparently two incompatible ways of naming abstract sockets: pad the sockaddr with 0s and use the entire thing as the name, or else don't, and just pass a shorter length value to the relevant functions. We previously only supported the former method. Add support for the latter. Also correctly handle "anonymous" unix sockaddrs (eg, the client side of a connection, or a socketpair() socket), and add unix domain socket support to the socket-client and socket-server test programs to make sure this all works. https://bugzilla.gnome.org/show_bug.cgi?id=615960
2025-07-29 13:23:31 +02:00 · 2010-04-20 17:23:49 -04:00
parent 5e892de8af
commit 19d8cc3375
11 changed files with 439 additions and 110 deletions
--- a/gio/gunixsocketaddress.c
+++ b/gio/gunixsocketaddress.c
@@ -36,6 +36,16 @@
 * @short_description: UNIX GSocketAddress
 *
 * Support for UNIX-domain (aka local) sockets.
+ *
+ * Unix domain sockets are generally visible in the filesystem.
+ * However, some systems support abstract socket names which are not
+ * visible in the filesystem and not affected by the filesystem
+ * permissions, visibility, etc. Currently this is only supported
+ * under Linux. If you attempt to use abstract sockets on other
+ * systems, function calls may return %G_IO_ERROR_NOT_SUPPORTED
+ * errors. You can use
+ * g_unix_socket_address_abstract_names_supported() to see if abstract
+ * names are supported.
 */

 /**
@@ -52,6 +62,7 @@ enum
  PROP_PATH,
  PROP_PATH_AS_ARRAY,
  PROP_ABSTRACT,
+  PROP_ADDRESS_TYPE
 };

 #define UNIX_PATH_MAX sizeof (((struct sockaddr_un *) 0)->sun_path)
@@ -62,7 +73,7 @@ struct _GUnixSocketAddressPrivate
 			       we can guarantee zero termination of abstract
 			       pathnames in the get_path() API */
  gsize path_len; /* Not including any terminating zeros */
-  gboolean abstract;
+  GUnixSocketAddressType address_type;
 };

 static void
@@ -96,10 +107,6 @@ g_unix_socket_address_set_property (GObject      *object,
 	  /* Clip to fit in UNIX_PATH_MAX with zero termination or first byte */
 	  len = MIN (array->len, UNIX_PATH_MAX-1);

-	  /* Remove any trailing zeros from path_len */
-	  while (len > 0 && array->data[len-1] == 0)
-	    len--;
-
 	  memcpy (address->priv->path, array->data, len);
 	  address->priv->path[len] = 0; /* Ensure null-terminated */
 	  address->priv->path_len = len;
@@ -107,7 +114,26 @@ g_unix_socket_address_set_property (GObject      *object,
      break;

    case PROP_ABSTRACT:
-      address->priv->abstract = g_value_get_boolean (value);
+      /* If the caller already set PROP_ADDRESS_TYPE, don't let the
+       * default value of PROP_ABSTRACT overwrite it.
+       */
+      if (address->priv->address_type != G_UNIX_SOCKET_ADDRESS_INVALID)
+	return;
+
+      if (g_value_get_boolean (value))
+	address->priv->address_type = G_UNIX_SOCKET_ADDRESS_ABSTRACT_PADDED;
+      else
+	address->priv->address_type = G_UNIX_SOCKET_ADDRESS_PATH;
+      break;
+
+    case PROP_ADDRESS_TYPE:
+      /* If the caller already set PROP_ABSTRACT, don't let the
+       * default value of PROP_ADDRESS_TYPE overwrite it.
+       */
+      if (address->priv->address_type != G_UNIX_SOCKET_ADDRESS_INVALID)
+	return;
+
+      address->priv->address_type = g_value_get_enum (value);
      break;

    default:
@@ -137,7 +163,13 @@ g_unix_socket_address_get_property (GObject    *object,
 	break;

      case PROP_ABSTRACT:
-	g_value_set_boolean (value, address->priv->abstract);
+	g_value_set_boolean (value, (address->priv->address_type == G_UNIX_SOCKET_ADDRESS_ABSTRACT ||
+				     address->priv->address_type == G_UNIX_SOCKET_ADDRESS_ABSTRACT_PADDED));
+
+	break;
+
+      case PROP_ADDRESS_TYPE:
+	g_value_set_enum (value, address->priv->address_type);
 	break;

      default:
@@ -156,7 +188,17 @@ g_unix_socket_address_get_family (GSocketAddress *address)
 static gssize
 g_unix_socket_address_get_native_size (GSocketAddress *address)
 {
-  return sizeof (struct sockaddr_un);
+  GUnixSocketAddress *addr = G_UNIX_SOCKET_ADDRESS (address);
+
+  switch (addr->priv->address_type)
+    {
+    case G_UNIX_SOCKET_ADDRESS_ANONYMOUS:
+      return G_STRUCT_OFFSET(struct sockaddr_un, sun_path);
+    case G_UNIX_SOCKET_ADDRESS_ABSTRACT:
+      return G_STRUCT_OFFSET(struct sockaddr_un, sun_path) + addr->priv->path_len + 1;
+    default:
+      return sizeof (struct sockaddr_un);
+    }
 }

 static gboolean
@@ -167,32 +209,43 @@ g_unix_socket_address_to_native (GSocketAddress *address,
 {
  GUnixSocketAddress *addr = G_UNIX_SOCKET_ADDRESS (address);
  struct sockaddr_un *sock;
+  gssize socklen;

-  if (destlen < sizeof (*sock))
+  socklen = g_unix_socket_address_get_native_size (address);
+  if (destlen < socklen)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NO_SPACE,
 			   _("Not enough space for socket address"));
      return FALSE;
    }

-  if (addr->priv->abstract &&
-      !g_unix_socket_address_abstract_names_supported ())
-    {
-      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
-			   _("Abstract unix domain socket addresses not supported on this system"));
-      return FALSE;
-    }
-
  sock = (struct sockaddr_un *) dest;
+  memset (sock, 0, socklen);
  sock->sun_family = AF_UNIX;
-  memset (sock->sun_path, 0, sizeof (sock->sun_path));
-  if (addr->priv->abstract)
+
+  switch (addr->priv->address_type)
    {
+    case G_UNIX_SOCKET_ADDRESS_INVALID:
+    case G_UNIX_SOCKET_ADDRESS_ANONYMOUS:
+      break;
+
+    case G_UNIX_SOCKET_ADDRESS_PATH:
+      strcpy (sock->sun_path, addr->priv->path);
+      break;
+
+    case G_UNIX_SOCKET_ADDRESS_ABSTRACT:
+    case G_UNIX_SOCKET_ADDRESS_ABSTRACT_PADDED:
+      if (!g_unix_socket_address_abstract_names_supported ())
+	{
+	  g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
+			       _("Abstract unix domain socket addresses not supported on this system"));
+	  return FALSE;
+	}
+
      sock->sun_path[0] = 0;
      memcpy (sock->sun_path+1, addr->priv->path, addr->priv->path_len);
+      break;
    }
-  else
-    strcpy (sock->sun_path, addr->priv->path);

  return TRUE;
 }
@@ -229,6 +282,15 @@ g_unix_socket_address_class_init (GUnixSocketAddressClass *klass)
 						       G_PARAM_READWRITE |
 						       G_PARAM_CONSTRUCT_ONLY |
 						       G_PARAM_STATIC_STRINGS));
+  /**
+   * GUnixSocketAddress:abstract:
+   *
+   * Whether or not this is an abstract address
+   *
+   * Deprecated: Use #GUnixSocketAddress:address-type, which
+   * distinguishes between zero-padded and non-zero-padded
+   * abstract addresses.
+   */
  g_object_class_install_property (gobject_class, PROP_ABSTRACT,
 				   g_param_spec_boolean ("abstract",
 							 P_("Abstract"),
@@ -237,6 +299,15 @@ g_unix_socket_address_class_init (GUnixSocketAddressClass *klass)
 							 G_PARAM_READWRITE |
 							 G_PARAM_CONSTRUCT_ONLY |
 							 G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_ADDRESS_TYPE,
+				   g_param_spec_enum ("address-type",
+						      P_("Address type"),
+						      P_("The type of UNIX socket address"),
+						      G_TYPE_UNIX_SOCKET_ADDRESS_TYPE,
+						      G_UNIX_SOCKET_ADDRESS_PATH,
+						      G_PARAM_READWRITE |
+						      G_PARAM_CONSTRUCT_ONLY |
+						      G_PARAM_STATIC_STRINGS));
 }

 static void
@@ -248,6 +319,7 @@ g_unix_socket_address_init (GUnixSocketAddress *address)

  memset (address->priv->path, 0, sizeof (address->priv->path));
  address->priv->path_len = -1;
+  address->priv->address_type = G_UNIX_SOCKET_ADDRESS_INVALID;
 }

 /**
@@ -277,35 +349,71 @@ g_unix_socket_address_new (const gchar *path)
 * @path: the abstract name
 * @path_len: the length of @path, or -1
 *
- * Creates a new abstract #GUnixSocketAddress for @path.
- *
- * Unix domain sockets are generally visible in the filesystem. However, some
- * systems support abstract socket name which are not visible in the
- * filesystem and not affected by the filesystem permissions, visibility, etc.
- *
- * Note that not all systems (really only Linux) support abstract
- * socket names, so if you use them on other systems function calls may
- * return %G_IO_ERROR_NOT_SUPPORTED errors. You can use
- * g_unix_socket_address_abstract_names_supported() to see if abstract
- * names are supported.
- *
- * If @path_len is -1 then @path is assumed to be a zero terminated
- * string (although in general abstract names need not be zero terminated
- * and can have embedded nuls). All bytes after @path_len up to the max size
- * of an abstract unix domain name is filled with zero bytes.
+ * Creates a new %G_UNIX_SOCKET_ADDRESS_ABSTRACT_PADDED
+ * #GUnixSocketAddress for @path.
 *
 * Returns: a new #GUnixSocketAddress
 *
- * Since: 2.22
+ * Deprecated: Use g_unix_socket_address_new_with_type().
 */
 GSocketAddress *
 g_unix_socket_address_new_abstract (const gchar *path,
-				    int path_len)
+				    gint         path_len)
+{
+  return g_unix_socket_address_new_with_type (path, path_len,
+					      G_UNIX_SOCKET_ADDRESS_ABSTRACT_PADDED);
+}
+
+/**
+ * g_unix_socket_address_new_with_type:
+ * @path: the name
+ * @path_len: the length of @path, or -1
+ * @type: a #GUnixSocketAddressType
+ *
+ * Creates a new #GUnixSocketAddress of type @type with name @path.
+ *
+ * If @type is %G_UNIX_SOCKET_ADDRESS_PATH, this is equivalent to
+ * calling g_unix_socket_address_new().
+ *
+ * If @path_type is %G_UNIX_SOCKET_ADDRESS_ABSTRACT, then @path_len
+ * bytes of @path will be copied to the socket's path, and only those
+ * bytes will be considered part of the name. (If @path_len is -1,
+ * then @path is assumed to be NUL-terminated.) For example, if @path
+ * was "test", then calling g_socket_address_get_native_size() on the
+ * returned socket would return 7 (2 bytes of overhead, 1 byte for the
+ * abstract-socket indicator byte, and 4 bytes for the name "test").
+ *
+ * If @path_type is %G_UNIX_SOCKET_ADDRESS_ABSTRACT_PADDED, then
+ * @path_len bytes of @path will be copied to the socket's path, the
+ * rest of the path will be padded with 0 bytes, and the entire
+ * zero-padded buffer will be considered the name. (As above, if
+ * @path_len is -1, then @path is assumed to be NUL-terminated.) In
+ * this case, g_socket_address_get_native_size() will always return
+ * the full size of a <literal>struct sockaddr_un</literal>, although
+ * g_unix_socket_address_get_path_len() will still return just the
+ * length of @path.
+ *
+ * %G_UNIX_SOCKET_ADDRESS_ABSTRACT is preferred over
+ * %G_UNIX_SOCKET_ADDRESS_ABSTRACT_PADDED for new programs. Of course,
+ * when connecting to a server created by another process, you must
+ * use the appropriate type corresponding to how that process created
+ * its listening socket.
+ *
+ * Returns: a new #GUnixSocketAddress
+ *
+ * Since: 2.26
+ */
+GSocketAddress *
+g_unix_socket_address_new_with_type (const gchar            *path,
+				     gint                    path_len,
+				     GUnixSocketAddressType  type)
 {
  GSocketAddress *address;
  GByteArray *array;

-  if (path_len == -1)
+  if (type == G_UNIX_SOCKET_ADDRESS_ANONYMOUS)
+    path_len = 0;
+  else if (path_len == -1)
    path_len = strlen (path);

  array = g_byte_array_sized_new (path_len);
@@ -314,7 +422,7 @@ g_unix_socket_address_new_abstract (const gchar *path,

  address = g_object_new (G_TYPE_UNIX_SOCKET_ADDRESS,
 			  "path-as-array", array,
-			  "abstract", TRUE,
+			  "address-type", type,
 			  NULL);

  g_byte_array_unref (array);
@@ -361,20 +469,39 @@ g_unix_socket_address_get_path_len (GUnixSocketAddress *address)
  return address->priv->path_len;
 }

+/**
+ * g_unix_socket_address_get_address_type:
+ * @address: a #GInetSocketAddress
+ *
+ * Gets @address's type.
+ *
+ * Returns: a #GUnixSocketAddressType
+ *
+ * Since: 2.26
+ */
+GUnixSocketAddressType
+g_unix_socket_address_get_address_type (GUnixSocketAddress *address)
+{
+  return address->priv->address_type;
+}
+
 /**
 * g_unix_socket_address_get_is_abstract:
 * @address: a #GInetSocketAddress
 *
- * Gets @address's path.
+ * Tests if @address is abstract.
 *
 * Returns: %TRUE if the address is abstract, %FALSE otherwise
 *
 * Since: 2.22
+ *
+ * Deprecated: Use g_unix_socket_address_get_address_type()
 */
 gboolean
 g_unix_socket_address_get_is_abstract (GUnixSocketAddress *address)
 {
-  return address->priv->abstract;
+  return (address->priv->address_type == G_UNIX_SOCKET_ADDRESS_ABSTRACT ||
+	  address->priv->address_type == G_UNIX_SOCKET_ADDRESS_ABSTRACT_PADDED);
 }

 /**