-- --
-- S p e c --
-- --
--- $Revision$
--- --
--- Copyright (C) 2001-2002 Ada Core Technologies, Inc. --
+-- Copyright (C) 2001-2010, AdaCore --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
+-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
--- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com). --
+-- GNAT was originally developed by the GNAT team at New York University. --
+-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This package provides an interface to the sockets communication facility
--- provided on many operating systems. Currently this is implemented on all
--- native GNAT ports except for VMS. It is not yet implemented on the Lynx
--- cross-ports.
+-- provided on many operating systems. This is implemented on the following
+-- platforms:
+
+-- All native ports, with restrictions as follows
+
+-- Multicast is available only on systems which provide support for this
+-- feature, so it is not available if Multicast is not supported, or not
+-- installed.
+
+-- The VMS implementation was implemented using the DECC RTL Socket API,
+-- and is thus subject to limitations in the implementation of this API.
+
+-- VxWorks cross ports fully implement this package
--- Another restriction is that there is no multicast support under Windows
--- or under any system on which the multicast support is not available or
--- installed.
+-- This package is not yet implemented on LynxOS or other cross ports
with Ada.Exceptions;
with Ada.Streams;
+with Ada.Unchecked_Deallocation;
+
+with Interfaces.C;
+
+with System.OS_Constants;
+with System.Storage_Elements;
package GNAT.Sockets is
-- Sockets are designed to provide a consistent communication facility
- -- between applications. This package provides an Ada-like intrerface
- -- similar to that proposed as part of the BSD socket layer. This is a
- -- system independent thick binding.
+ -- between applications. This package provides an Ada binding to the
+ -- the de-facto standard BSD sockets API. The documentation below covers
+ -- only the specific binding provided by this package. It assumes that
+ -- the reader is already familiar with general network programming and
+ -- sockets usage. A useful reference on this matter is W. Richard Stevens'
+ -- "UNIX Network Programming: The Sockets Networking API"
+ -- (ISBN: 0131411551).
+
+ -- GNAT.Sockets has been designed with several ideas in mind
+
+ -- This is a system independent interface. Therefore, we try as much as
+ -- possible to mask system incompatibilities. Some functionalities are not
+ -- available because there are not fully supported on some systems.
+
+ -- This is a thick binding. For instance, a major effort has been done to
+ -- avoid using memory addresses or untyped ints. We preferred to define
+ -- streams and enumeration types. Errors are not returned as returned
+ -- values but as exceptions.
- -- Here is a typical example of what you can do:
+ -- This package provides a POSIX-compliant interface (between two
+ -- different implementations of the same routine, we adopt the one closest
+ -- to the POSIX specification). For instance, using select(), the
+ -- notification of an asynchronous connect failure is delivered in the
+ -- write socket set (POSIX) instead of the exception socket set (NT).
+
+ -- The example below demonstrates various features of GNAT.Sockets:
-- with GNAT.Sockets; use GNAT.Sockets;
- --
+
-- with Ada.Text_IO;
-- with Ada.Exceptions; use Ada.Exceptions;
- --
+
-- procedure PingPong is
- --
+
-- Group : constant String := "239.255.128.128";
- -- -- Multicast groupe: administratively scoped IP address
- --
+ -- -- Multicast group: administratively scoped IP address
+
-- task Pong is
-- entry Start;
-- entry Stop;
-- end Pong;
- --
+
-- task body Pong is
-- Address : Sock_Addr_Type;
-- Server : Socket_Type;
-- Socket : Socket_Type;
-- Channel : Stream_Access;
- --
+
-- begin
-- accept Start;
--
-- -- Get an Internet address of a host (here the local host name).
-- -- Note that a host can have several addresses. Here we get
-- -- the first one which is supposed to be the official one.
- --
+
-- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
- --
+
-- -- Get a socket address that is an Internet address and a port
- --
- -- Address.Port := 5432;
- --
+
+ -- Address.Port := 5876;
+
-- -- The first step is to create a socket. Once created, this
- -- -- socket must be associated to with an address. Usually only
- -- -- a server (Pong here) needs to bind an address explicitly.
- -- -- Most of the time clients can skip this step because the
- -- -- socket routines will bind an arbitrary address to an unbound
- -- -- socket.
- --
+ -- -- socket must be associated to with an address. Usually only a
+ -- -- server (Pong here) needs to bind an address explicitly. Most
+ -- -- of the time clients can skip this step because the socket
+ -- -- routines will bind an arbitrary address to an unbound socket.
+
-- Create_Socket (Server);
- --
- -- -- Allow reuse of local addresses.
- --
+
+ -- -- Allow reuse of local addresses
+
-- Set_Socket_Option
-- (Server,
-- Socket_Level,
-- (Reuse_Address, True));
- --
+
-- Bind_Socket (Server, Address);
- --
- -- -- A server marks a socket as willing to receive connect events.
- --
+
+ -- -- A server marks a socket as willing to receive connect events
+
-- Listen_Socket (Server);
- --
+
-- -- Once a server calls Listen_Socket, incoming connects events
-- -- can be accepted. The returned Socket is a new socket that
-- -- represents the server side of the connection. Server remains
-- -- available to receive further connections.
- --
+
-- Accept_Socket (Server, Socket, Address);
- --
- -- -- Return a stream associated to the connected socket.
- --
+
+ -- -- Return a stream associated to the connected socket
+
-- Channel := Stream (Socket);
- --
+
-- -- Force Pong to block
- --
+
-- delay 0.2;
- --
- -- -- Receive and print message from client Ping.
- --
+
+ -- -- Receive and print message from client Ping
+
-- declare
-- Message : String := String'Input (Channel);
- --
+
-- begin
-- Ada.Text_IO.Put_Line (Message);
- --
- -- -- Send same message to server Pong.
- --
+
+ -- -- Send same message back to client Ping
+
-- String'Output (Channel, Message);
-- end;
- --
+
-- Close_Socket (Server);
-- Close_Socket (Socket);
- --
+
-- -- Part of the multicast example
- --
+
-- -- Create a datagram socket to send connectionless, unreliable
-- -- messages of a fixed maximum length.
- --
+
-- Create_Socket (Socket, Family_Inet, Socket_Datagram);
- --
- -- -- Allow reuse of local addresses.
- --
+
+ -- -- Allow reuse of local addresses
+
-- Set_Socket_Option
-- (Socket,
-- Socket_Level,
-- (Reuse_Address, True));
- --
- -- -- Join a multicast group.
- --
- -- Set_Socket_Option
- -- (Socket,
- -- IP_Protocol_For_IP_Level,
- -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
- --
+
-- -- Controls the live time of the datagram to avoid it being
-- -- looped forever due to routing errors. Routers decrement
-- -- the TTL of every datagram as it traverses from one network
-- -- to another and when its value reaches 0 the packet is
-- -- dropped. Default is 1.
- --
+
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Multicast_TTL, 1));
- --
- -- -- Want the data you send to be looped back to your host.
- --
+
+ -- -- Want the data you send to be looped back to your host
+
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Multicast_Loop, True));
- --
- -- -- If this socket is intended to receive messages, bind it to a
- -- -- given socket address.
- --
+
+ -- -- If this socket is intended to receive messages, bind it
+ -- -- to a given socket address.
+
-- Address.Addr := Any_Inet_Addr;
-- Address.Port := 55505;
- --
+
-- Bind_Socket (Socket, Address);
- --
+
+ -- -- Join a multicast group
+
+ -- -- Portability note: On Windows, this option may be set only
+ -- -- on a bound socket.
+
+ -- Set_Socket_Option
+ -- (Socket,
+ -- IP_Protocol_For_IP_Level,
+ -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
+
-- -- If this socket is intended to send messages, provide the
-- -- receiver socket address.
- --
+
-- Address.Addr := Inet_Addr (Group);
-- Address.Port := 55506;
- --
+
-- Channel := Stream (Socket, Address);
- --
- -- -- Receive and print message from client Ping.
- --
+
+ -- -- Receive and print message from client Ping
+
-- declare
-- Message : String := String'Input (Channel);
- --
+
-- begin
- --
- -- -- Get the address of the sender.
- --
+ -- -- Get the address of the sender
+
-- Address := Get_Address (Channel);
-- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
- --
- -- -- Send same message to server Pong.
- --
+
+ -- -- Send same message back to client Ping
+
-- String'Output (Channel, Message);
-- end;
- --
+
-- Close_Socket (Socket);
- --
+
-- accept Stop;
- --
+
-- exception when E : others =>
-- Ada.Text_IO.Put_Line
-- (Exception_Name (E) & ": " & Exception_Message (E));
-- end Pong;
- --
+
-- task Ping is
-- entry Start;
-- entry Stop;
-- end Ping;
- --
+
-- task body Ping is
-- Address : Sock_Addr_Type;
-- Socket : Socket_Type;
-- Channel : Stream_Access;
- --
+
-- begin
-- accept Start;
- --
- -- -- See comments in Ping section for the first steps.
- --
+
+ -- -- See comments in Ping section for the first steps
+
-- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
- -- Address.Port := 5432;
+ -- Address.Port := 5876;
-- Create_Socket (Socket);
- --
+
-- Set_Socket_Option
-- (Socket,
-- Socket_Level,
-- (Reuse_Address, True));
- --
+
-- -- Force Pong to block
- --
+
-- delay 0.2;
- --
+
-- -- If the client's socket is not bound, Connect_Socket will
-- -- bind to an unused address. The client uses Connect_Socket to
-- -- create a logical connection between the client's socket and
-- -- a server's socket returned by Accept_Socket.
- --
+
-- Connect_Socket (Socket, Address);
- --
+
-- Channel := Stream (Socket);
- --
- -- -- Send message to server Pong.
- --
+
+ -- -- Send message to server Pong
+
-- String'Output (Channel, "Hello world");
- --
+
-- -- Force Ping to block
- --
+
-- delay 0.2;
- --
- -- -- Receive and print message from server Pong.
- --
+
+ -- -- Receive and print message from server Pong
+
-- Ada.Text_IO.Put_Line (String'Input (Channel));
-- Close_Socket (Socket);
- --
- -- -- Part of multicast example. Code similar to Pong's one.
- --
+
+ -- -- Part of multicast example. Code similar to Pong's one
+
-- Create_Socket (Socket, Family_Inet, Socket_Datagram);
- --
+
-- Set_Socket_Option
-- (Socket,
-- Socket_Level,
-- (Reuse_Address, True));
- --
- -- Set_Socket_Option
- -- (Socket,
- -- IP_Protocol_For_IP_Level,
- -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
- --
+
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Multicast_TTL, 1));
- --
+
-- Set_Socket_Option
-- (Socket,
-- IP_Protocol_For_IP_Level,
-- (Multicast_Loop, True));
- --
+
-- Address.Addr := Any_Inet_Addr;
-- Address.Port := 55506;
- --
+
-- Bind_Socket (Socket, Address);
- --
+
+ -- Set_Socket_Option
+ -- (Socket,
+ -- IP_Protocol_For_IP_Level,
+ -- (Add_Membership, Inet_Addr (Group), Any_Inet_Addr));
+
-- Address.Addr := Inet_Addr (Group);
-- Address.Port := 55505;
- --
+
-- Channel := Stream (Socket, Address);
- --
- -- -- Send message to server Pong.
- --
+
+ -- -- Send message to server Pong
+
-- String'Output (Channel, "Hello world");
- --
- -- -- Receive and print message from server Pong.
- --
+
+ -- -- Receive and print message from server Pong
+
-- declare
-- Message : String := String'Input (Channel);
- --
+
-- begin
-- Address := Get_Address (Channel);
-- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
-- end;
- --
+
-- Close_Socket (Socket);
- --
+
-- accept Stop;
- --
+
-- exception when E : others =>
-- Ada.Text_IO.Put_Line
-- (Exception_Name (E) & ": " & Exception_Message (E));
-- end Ping;
- --
+
-- begin
- -- -- Indicate whether the thread library provides process
- -- -- blocking IO. Basically, if you are not using FSU threads
- -- -- the default is ok.
- --
- -- Initialize (Process_Blocking_IO => False);
+ -- Initialize;
-- Ping.Start;
-- Pong.Start;
-- Ping.Stop;
-- Finalize;
-- end PingPong;
- procedure Initialize (Process_Blocking_IO : Boolean := False);
- -- Initialize must be called before using any socket routines. If
- -- the thread library provides process blocking IO - basically
- -- with FSU threads - GNAT.Sockets should be initialized with a
- -- value of True to simulate thread blocking IO. Further calls to
- -- Initialize will be ignored.
+ package SOSC renames System.OS_Constants;
+ -- Renaming used to provide short-hand notations throughout the sockets
+ -- binding. Note that System.OS_Constants is an internal unit, and the
+ -- entities declared therein are not meant for direct access by users,
+ -- including through this renaming.
+
+ procedure Initialize;
+ pragma Obsolescent
+ (Entity => Initialize,
+ Message => "explicit initialization is no longer required");
+ -- Initialize must be called before using any other socket routines.
+ -- Note that this operation is a no-op on UNIX platforms, but applications
+ -- should make sure to call it if portability is expected: some platforms
+ -- (such as Windows) require initialization before any socket operation.
+ -- This is now a no-op (initialization and finalization are done
+ -- automatically).
+
+ procedure Initialize (Process_Blocking_IO : Boolean);
+ pragma Obsolescent
+ (Entity => Initialize,
+ Message => "passing a parameter to Initialize is no longer supported");
+ -- Previous versions of GNAT.Sockets used to require the user to indicate
+ -- whether socket I/O was process- or thread-blocking on the platform.
+ -- This property is now determined automatically when the run-time library
+ -- is built. The old version of Initialize, taking a parameter, is kept
+ -- for compatibility reasons, but this interface is obsolete (and if the
+ -- value given is wrong, an exception will be raised at run time).
+ -- This is now a no-op (initialization and finalization are done
+ -- automatically).
procedure Finalize;
+ pragma Obsolescent
+ (Entity => Finalize,
+ Message => "explicit finalization is no longer required");
-- After Finalize is called it is not possible to use any routines
-- exported in by this package. This procedure is idempotent.
+ -- This is now a no-op (initialization and finalization are done
+ -- automatically).
type Socket_Type is private;
- -- Sockets are used to implement a reliable bi-directional
- -- point-to-point, stream-based connections between
- -- hosts. No_Socket provides a special value to denote
- -- uninitialized sockets.
+ -- Sockets are used to implement a reliable bi-directional point-to-point,
+ -- stream-based connections between hosts. No_Socket provides a special
+ -- value to denote uninitialized sockets.
No_Socket : constant Socket_Type;
+ type Selector_Type is limited private;
+ type Selector_Access is access all Selector_Type;
+ -- Selector objects are used to wait for i/o events to occur on sockets
+
+ Null_Selector : constant Selector_Type;
+ -- The Null_Selector can be used in place of a normal selector without
+ -- having to call Create_Selector if the use of Abort_Selector is not
+ -- required.
+
+ -- Timeval_Duration is a subtype of Standard.Duration because the full
+ -- range of Standard.Duration cannot be represented in the equivalent C
+ -- structure. Moreover, negative values are not allowed to avoid system
+ -- incompatibilities.
+
+ Immediate : constant Duration := 0.0;
+
+ Timeval_Forever : constant := 2.0 ** (SOSC.SIZEOF_tv_sec * 8 - 1) - 1.0;
+ Forever : constant Duration :=
+ Duration'Min (Duration'Last, Timeval_Forever);
+
+ subtype Timeval_Duration is Duration range Immediate .. Forever;
+
+ subtype Selector_Duration is Timeval_Duration;
+ -- Timeout value for selector operations
+
+ type Selector_Status is (Completed, Expired, Aborted);
+ -- Completion status of a selector operation, indicated as follows:
+ -- Complete: one of the expected events occurred
+ -- Expired: no event occurred before the expiration of the timeout
+ -- Aborted: an external action cancelled the wait operation before
+ -- any event occurred.
+
Socket_Error : exception;
- -- There is only one exception in this package to deal with an
- -- error during a socket routine. Once raised, its message
- -- contains a string describing the error code.
+ -- There is only one exception in this package to deal with an error during
+ -- a socket routine. Once raised, its message contains a string describing
+ -- the error code.
function Image (Socket : Socket_Type) return String;
-- Return a printable string for Socket
function To_C (Socket : Socket_Type) return Integer;
- -- Return a file descriptor to be used by external subprograms
- -- especially the C functions that are not yet interfaced in this
- -- package.
+ -- Return a file descriptor to be used by external subprograms. This is
+ -- useful for C functions that are not yet interfaced in this package.
type Family_Type is (Family_Inet, Family_Inet6);
- -- Address family (or protocol family) identifies the
- -- communication domain and groups protocols with similar address
- -- formats. IPv6 will soon be supported.
+ -- Address family (or protocol family) identifies the communication domain
+ -- and groups protocols with similar address formats.
type Mode_Type is (Socket_Stream, Socket_Datagram);
- -- Stream sockets provide connection-oriented byte
- -- streams. Datagram sockets support unreliable connectionless
- -- message based communication.
+ -- Stream sockets provide connection-oriented byte streams. Datagram
+ -- sockets support unreliable connectionless message based communication.
type Shutmode_Type is (Shut_Read, Shut_Write, Shut_Read_Write);
- -- When a process closes a socket, the policy is to retain any
- -- data queued until either a delivery or a timeout expiration (in
- -- this case, the data are discarded). A finer control is
- -- available through shutdown. With Shut_Read, no more data can be
- -- received from the socket. With_Write, no more data can be
- -- transmitted. Neither transmission nor reception can be
+ -- When a process closes a socket, the policy is to retain any data queued
+ -- until either a delivery or a timeout expiration (in this case, the data
+ -- are discarded). A finer control is available through shutdown. With
+ -- Shut_Read, no more data can be received from the socket. With_Write, no
+ -- more data can be transmitted. Neither transmission nor reception can be
-- performed with Shut_Read_Write.
- type Port_Type is new Natural;
- -- Classical port definition. No_Port provides a special value to
- -- denote uninitialized port. Any_Port provides a special value
- -- enabling all ports.
+ type Port_Type is range 0 .. 16#ffff#;
+ -- TCP/UDP port number
Any_Port : constant Port_Type;
- No_Port : constant Port_Type;
+ -- All ports
+
+ No_Port : constant Port_Type;
+ -- Uninitialized port number
type Inet_Addr_Type (Family : Family_Type := Family_Inet) is private;
- -- An Internet address depends on an address family (IPv4 contains
- -- 4 octets and Ipv6 contains 16 octets). Any_Inet_Address is a
- -- special value treated like a wildcard enabling all addresses.
- -- No_Inet_Addr provides a special value to denote uninitialized
- -- inet addresses.
+ -- An Internet address depends on an address family (IPv4 contains 4 octets
+ -- and IPv6 contains 16 octets). Any_Inet_Addr is a special value treated
+ -- like a wildcard enabling all addresses. No_Inet_Addr provides a special
+ -- value to denote uninitialized inet addresses.
+
+ Any_Inet_Addr : constant Inet_Addr_Type;
+ No_Inet_Addr : constant Inet_Addr_Type;
+ Broadcast_Inet_Addr : constant Inet_Addr_Type;
+ Loopback_Inet_Addr : constant Inet_Addr_Type;
+
+ -- Useful constants for IPv4 multicast addresses
- Any_Inet_Addr : constant Inet_Addr_Type;
- No_Inet_Addr : constant Inet_Addr_Type;
+ Unspecified_Group_Inet_Addr : constant Inet_Addr_Type;
+ All_Hosts_Group_Inet_Addr : constant Inet_Addr_Type;
+ All_Routers_Group_Inet_Addr : constant Inet_Addr_Type;
type Sock_Addr_Type (Family : Family_Type := Family_Inet) is record
Addr : Inet_Addr_Type (Family);
Port : Port_Type;
end record;
- -- Socket addresses fully define a socket connection with a
- -- protocol family, an Internet address and a port. No_Sock_Addr
- -- provides a special value for uninitialized socket addresses.
+ -- Socket addresses fully define a socket connection with protocol family,
+ -- an Internet address and a port. No_Sock_Addr provides a special value
+ -- for uninitialized socket addresses.
No_Sock_Addr : constant Sock_Addr_Type;
function Image (Value : Inet_Addr_Type) return String;
- -- Return an image of an Internet address. IPv4 notation consists
- -- in 4 octets in decimal format separated by dots. IPv6 notation
- -- consists in 16 octets in hexadecimal format separated by
- -- colons (and possibly dots).
+ -- Return an image of an Internet address. IPv4 notation consists in 4
+ -- octets in decimal format separated by dots. IPv6 notation consists in
+ -- 16 octets in hexadecimal format separated by colons (and possibly
+ -- dots).
function Image (Value : Sock_Addr_Type) return String;
- -- Return inet address image and port image separated by a colon.
+ -- Return inet address image and port image separated by a colon
function Inet_Addr (Image : String) return Inet_Addr_Type;
-- Convert address image from numbers-and-dots notation into an
-- inet address.
- -- Host entries provide a complete information on a given host:
- -- the official name, an array of alternative names or aliases and
- -- array of network addresses.
+ -- Host entries provide complete information on a given host: the official
+ -- name, an array of alternative names or aliases and array of network
+ -- addresses.
type Host_Entry_Type
(Aliases_Length, Addresses_Length : Natural) is private;
-- Return number of addresses in host entry
function Aliases
- (E : Host_Entry_Type;
- N : Positive := 1)
- return String;
- -- Return N'th aliases in host entry. The first index is 1.
+ (E : Host_Entry_Type;
+ N : Positive := 1) return String;
+ -- Return N'th aliases in host entry. The first index is 1
function Addresses
- (E : Host_Entry_Type;
- N : Positive := 1)
- return Inet_Addr_Type;
- -- Return N'th addresses in host entry. The first index is 1.
+ (E : Host_Entry_Type;
+ N : Positive := 1) return Inet_Addr_Type;
+ -- Return N'th addresses in host entry. The first index is 1
Host_Error : exception;
- -- Exception raised by the two following procedures. Once raised,
- -- its message contains a string describing the error code. This
- -- exception is raised when an host entry can not be retrieved.
+ -- Exception raised by the two following procedures. Once raised, its
+ -- message contains a string describing the error code. This exception is
+ -- raised when an host entry cannot be retrieved.
function Get_Host_By_Address
(Address : Inet_Addr_Type;
- Family : Family_Type := Family_Inet)
- return Host_Entry_Type;
- -- Return host entry structure for the given inet address
+ Family : Family_Type := Family_Inet) return Host_Entry_Type;
+ -- Return host entry structure for the given Inet address. Note that no
+ -- result will be returned if there is no mapping of this IP address to a
+ -- host name in the system tables (host database, DNS or otherwise).
function Get_Host_By_Name
- (Name : String)
- return Host_Entry_Type;
- -- Return host entry structure for the given host name
+ (Name : String) return Host_Entry_Type;
+ -- Return host entry structure for the given host name. Here name is
+ -- either a host name, or an IP address. If Name is an IP address, this
+ -- is equivalent to Get_Host_By_Address (Inet_Addr (Name)).
function Host_Name return String;
-- Return the name of the current host
- -- Errors are described by an enumeration type. There is only one
- -- exception Socket_Error in this package to deal with an error
- -- during a socket routine. Once raised, its message contains the
- -- error code between brackets and a string describing the error code.
+ type Service_Entry_Type (Aliases_Length : Natural) is private;
+ -- Service entries provide complete information on a given service: the
+ -- official name, an array of alternative names or aliases and the port
+ -- number.
- -- The name of the enumeration constant documents the error condition.
+ function Official_Name (S : Service_Entry_Type) return String;
+ -- Return official name in service entry
+
+ function Port_Number (S : Service_Entry_Type) return Port_Type;
+ -- Return port number in service entry
+
+ function Protocol_Name (S : Service_Entry_Type) return String;
+ -- Return Protocol in service entry (usually UDP or TCP)
+
+ function Aliases_Length (S : Service_Entry_Type) return Natural;
+ -- Return number of aliases in service entry
+
+ function Aliases
+ (S : Service_Entry_Type;
+ N : Positive := 1) return String;
+ -- Return N'th aliases in service entry (the first index is 1)
+
+ function Get_Service_By_Name
+ (Name : String;
+ Protocol : String) return Service_Entry_Type;
+ -- Return service entry structure for the given service name
+
+ function Get_Service_By_Port
+ (Port : Port_Type;
+ Protocol : String) return Service_Entry_Type;
+ -- Return service entry structure for the given service port number
+
+ Service_Error : exception;
+ -- Comment required ???
+
+ -- Errors are described by an enumeration type. There is only one exception
+ -- Socket_Error in this package to deal with an error during a socket
+ -- routine. Once raised, its message contains the error code between
+ -- brackets and a string describing the error code.
+
+ -- The name of the enumeration constant documents the error condition
+ -- Note that on some platforms, a single error value is used for both
+ -- EWOULDBLOCK and EAGAIN. Both errors are therefore always reported as
+ -- Resource_Temporarily_Unavailable.
type Error_Type is
- (Permission_Denied,
+ (Success,
+ Permission_Denied,
Address_Already_In_Use,
Cannot_Assign_Requested_Address,
Address_Family_Not_Supported_By_Protocol,
Operation_Already_In_Progress,
Bad_File_Descriptor,
+ Software_Caused_Connection_Abort,
Connection_Refused,
+ Connection_Reset_By_Peer,
+ Destination_Address_Required,
Bad_Address,
+ Host_Is_Down,
+ No_Route_To_Host,
Operation_Now_In_Progress,
Interrupted_System_Call,
Invalid_Argument,
Input_Output_Error,
Transport_Endpoint_Already_Connected,
+ Too_Many_Symbolic_Links,
+ Too_Many_Open_Files,
Message_Too_Long,
+ File_Name_Too_Long,
+ Network_Is_Down,
+ Network_Dropped_Connection_Because_Of_Reset,
Network_Is_Unreachable,
No_Buffer_Space_Available,
Protocol_Not_Available,
Transport_Endpoint_Not_Connected,
+ Socket_Operation_On_Non_Socket,
Operation_Not_Supported,
+ Protocol_Family_Not_Supported,
Protocol_Not_Supported,
+ Protocol_Wrong_Type_For_Socket,
+ Cannot_Send_After_Transport_Endpoint_Shutdown,
Socket_Type_Not_Supported,
Connection_Timed_Out,
+ Too_Many_References,
Resource_Temporarily_Unavailable,
+ Broken_Pipe,
Unknown_Host,
Host_Name_Lookup_Failure,
- No_Address_Associated_With_Name,
+ Non_Recoverable_Error,
Unknown_Server_Error,
Cannot_Resolve_Error);
- -- Get_Socket_Options and Set_Socket_Options manipulate options
- -- associated with a socket. Options may exist at multiple
- -- protocol levels in the communication stack. Socket_Level is the
- -- uppermost socket level.
-
- type Level_Type is (
- Socket_Level,
- IP_Protocol_For_IP_Level,
- IP_Protocol_For_UDP_Level,
- IP_Protocol_For_TCP_Level);
-
- -- There are several options available to manipulate sockets. Each
- -- option has a name and several values available. Most of the
- -- time, the value is a boolean to enable or disable this option.
-
- type Option_Name is (
- Keep_Alive, -- Enable sending of keep-alive messages
- Reuse_Address, -- Allow bind to reuse local address
- Broadcast, -- Enable datagram sockets to recv/send broadcast packets
- Send_Buffer, -- Set/get the maximum socket send buffer in bytes
- Receive_Buffer, -- Set/get the maximum socket recv buffer in bytes
- Linger, -- Shutdown wait for msg to be sent or timeout occur
- Error, -- Get and clear the pending socket error
- No_Delay, -- Do not delay send to coalesce packets (TCP_NODELAY)
- Add_Membership, -- Join a multicast group
- Drop_Membership, -- Leave a multicast group
- Multicast_TTL, -- Indicates the time-to-live of sent multicast packets
- Multicast_Loop); -- Sent multicast packets are looped to the local socket
+ -- Get_Socket_Options and Set_Socket_Options manipulate options associated
+ -- with a socket. Options may exist at multiple protocol levels in the
+ -- communication stack. Socket_Level is the uppermost socket level.
+
+ type Level_Type is
+ (Socket_Level,
+ IP_Protocol_For_IP_Level,
+ IP_Protocol_For_UDP_Level,
+ IP_Protocol_For_TCP_Level);
+
+ -- There are several options available to manipulate sockets. Each option
+ -- has a name and several values available. Most of the time, the value is
+ -- a boolean to enable or disable this option.
+
+ type Option_Name is
+ (Keep_Alive, -- Enable sending of keep-alive messages
+ Reuse_Address, -- Allow bind to reuse local address
+ Broadcast, -- Enable datagram sockets to recv/send broadcasts
+ Send_Buffer, -- Set/get the maximum socket send buffer in bytes
+ Receive_Buffer, -- Set/get the maximum socket recv buffer in bytes
+ Linger, -- Shutdown wait for msg to be sent or timeout occur
+ Error, -- Get and clear the pending socket error
+ No_Delay, -- Do not delay send to coalesce data (TCP_NODELAY)
+ Add_Membership, -- Join a multicast group
+ Drop_Membership, -- Leave a multicast group
+ Multicast_If, -- Set default out interface for multicast packets
+ Multicast_TTL, -- Set the time-to-live of sent multicast packets
+ Multicast_Loop, -- Sent multicast packets are looped to local socket
+ Receive_Packet_Info, -- Receive low level packet info as ancillary data
+ Send_Timeout, -- Set timeout value for output
+ Receive_Timeout); -- Set timeout value for input
type Option_Type (Name : Option_Name := Keep_Alive) is record
case Name is
- when Keep_Alive |
- Reuse_Address |
- Broadcast |
- Linger |
- No_Delay |
- Multicast_Loop =>
+ when Keep_Alive |
+ Reuse_Address |
+ Broadcast |
+ Linger |
+ No_Delay |
+ Receive_Packet_Info |
+ Multicast_Loop =>
Enabled : Boolean;
case Name is
when Add_Membership |
Drop_Membership =>
- Multiaddr : Inet_Addr_Type;
- Interface : Inet_Addr_Type;
+ Multicast_Address : Inet_Addr_Type;
+ Local_Interface : Inet_Addr_Type;
+
+ when Multicast_If =>
+ Outgoing_If : Inet_Addr_Type;
when Multicast_TTL =>
Time_To_Live : Natural;
+ when Send_Timeout |
+ Receive_Timeout =>
+ Timeout : Timeval_Duration;
+
end case;
end record;
- -- There are several controls available to manipulate
- -- sockets. Each option has a name and several values available.
- -- These controls differ from the socket options in that they are
- -- not specific to sockets but are available for any device.
+ -- There are several controls available to manipulate sockets. Each option
+ -- has a name and several values available. These controls differ from the
+ -- socket options in that they are not specific to sockets but are
+ -- available for any device.
- type Request_Name is (
- Non_Blocking_IO, -- Cause a caller not to wait on blocking operations.
+ type Request_Name is
+ (Non_Blocking_IO, -- Cause a caller not to wait on blocking operations
N_Bytes_To_Read); -- Return the number of bytes available to read
type Request_Type (Name : Request_Name := Non_Blocking_IO) is record
end case;
end record;
+ -- A request flag allows to specify the type of message transmissions or
+ -- receptions. A request flag can be combination of zero or more
+ -- predefined request flags.
+
+ type Request_Flag_Type is private;
+
+ No_Request_Flag : constant Request_Flag_Type;
+ -- This flag corresponds to the normal execution of an operation
+
+ Process_Out_Of_Band_Data : constant Request_Flag_Type;
+ -- This flag requests that the receive or send function operates on
+ -- out-of-band data when the socket supports this notion (e.g.
+ -- Socket_Stream).
+
+ Peek_At_Incoming_Data : constant Request_Flag_Type;
+ -- This flag causes the receive operation to return data from the beginning
+ -- of the receive queue without removing that data from the queue. A
+ -- subsequent receive call will return the same data.
+
+ Wait_For_A_Full_Reception : constant Request_Flag_Type;
+ -- This flag requests that the operation block until the full request is
+ -- satisfied. However, the call may still return less data than requested
+ -- if a signal is caught, an error or disconnect occurs, or the next data
+ -- to be received is of a different type than that returned. Note that
+ -- this flag depends on support in the underlying sockets implementation,
+ -- and is not supported under Windows.
+
+ Send_End_Of_Record : constant Request_Flag_Type;
+ -- This flag indicates that the entire message has been sent and so this
+ -- terminates the record.
+
+ function "+" (L, R : Request_Flag_Type) return Request_Flag_Type;
+ -- Combine flag L with flag R
+
+ type Stream_Element_Reference is access all Ada.Streams.Stream_Element;
+
+ type Vector_Element is record
+ Base : Stream_Element_Reference;
+ Length : Ada.Streams.Stream_Element_Count;
+ end record;
+
+ type Vector_Type is array (Integer range <>) of Vector_Element;
+
procedure Create_Socket
(Socket : out Socket_Type;
Family : Family_Type := Family_Inet;
Mode : Mode_Type := Socket_Stream);
- -- Create an endpoint for communication. Raise Socket_Error on error.
+ -- Create an endpoint for communication. Raises Socket_Error on error
procedure Accept_Socket
(Server : Socket_Type;
Socket : out Socket_Type;
Address : out Sock_Addr_Type);
- -- Extract the first connection request on the queue of pending
- -- connections, creates a new connected socket with mostly the
- -- same properties as Server, and allocates a new socket. The
- -- returned Address is filled in with the address of the
- -- connection. Raise Socket_Error on error.
+ -- Extracts the first connection request on the queue of pending
+ -- connections, creates a new connected socket with mostly the same
+ -- properties as Server, and allocates a new socket. The returned Address
+ -- is filled in with the address of the connection. Raises Socket_Error on
+ -- error.
+
+ procedure Accept_Socket
+ (Server : Socket_Type;
+ Socket : out Socket_Type;
+ Address : out Sock_Addr_Type;
+ Timeout : Selector_Duration;
+ Selector : access Selector_Type := null;
+ Status : out Selector_Status);
+ -- Accept a new connection on Server using Accept_Socket, waiting no longer
+ -- than the given timeout duration. Status is set to indicate whether the
+ -- operation completed successfully, timed out, or was aborted. If Selector
+ -- is not null, the designated selector is used to wait for the socket to
+ -- become available, else a private selector object is created by this
+ -- procedure and destroyed before it returns.
procedure Bind_Socket
(Socket : Socket_Type;
-- Socket_Error on error.
procedure Close_Socket (Socket : Socket_Type);
- -- Close a socket and more specifically a non-connected socket.
+ -- Close a socket and more specifically a non-connected socket
procedure Connect_Socket
(Socket : Socket_Type;
- Server : in out Sock_Addr_Type);
- -- Make a connection to another socket which has the address of
- -- Server. Raise Socket_Error on error.
+ Server : Sock_Addr_Type);
+ -- Make a connection to another socket which has the address of Server.
+ -- Raises Socket_Error on error.
+
+ procedure Connect_Socket
+ (Socket : Socket_Type;
+ Server : Sock_Addr_Type;
+ Timeout : Selector_Duration;
+ Selector : access Selector_Type := null;
+ Status : out Selector_Status);
+ -- Connect Socket to the given Server address using Connect_Socket, waiting
+ -- no longer than the given timeout duration. Status is set to indicate
+ -- whether the operation completed successfully, timed out, or was aborted.
+ -- If Selector is not null, the designated selector is used to wait for the
+ -- socket to become available, else a private selector object is created
+ -- by this procedure and destroyed before it returns.
procedure Control_Socket
(Socket : Socket_Type;
Request : in out Request_Type);
- -- Obtain or set parameter values that control the socket. This
- -- control differs from the socket options in that they are not
- -- specific to sockets but are avaiable for any device.
+ -- Obtain or set parameter values that control the socket. This control
+ -- differs from the socket options in that they are not specific to sockets
+ -- but are available for any device.
function Get_Peer_Name (Socket : Socket_Type) return Sock_Addr_Type;
-- Return the peer or remote socket address of a socket. Raise
-- Socket_Error on error.
function Get_Socket_Name (Socket : Socket_Type) return Sock_Addr_Type;
- -- Return the local or current socket address of a socket. Raise
- -- Socket_Error on error.
+ -- Return the local or current socket address of a socket. Return
+ -- No_Sock_Addr on error (e.g. socket closed or not locally bound).
function Get_Socket_Option
(Socket : Socket_Type;
Level : Level_Type := Socket_Level;
- Name : Option_Name)
- return Option_Type;
- -- Get the options associated with a socket. Raise Socket_Error on
- -- error.
+ Name : Option_Name) return Option_Type;
+ -- Get the options associated with a socket. Raises Socket_Error on error
procedure Listen_Socket
(Socket : Socket_Type;
- Length : Positive := 15);
- -- To accept connections, a socket is first created with
- -- Create_Socket, a willingness to accept incoming connections and
- -- a queue Length for incoming connections are specified. Raise
- -- Socket_Error on error.
+ Length : Natural := 15);
+ -- To accept connections, a socket is first created with Create_Socket,
+ -- a willingness to accept incoming connections and a queue Length for
+ -- incoming connections are specified. Raise Socket_Error on error.
+ -- The queue length of 15 is an example value that should be appropriate
+ -- in usual cases. It can be adjusted according to each application's
+ -- particular requirements.
procedure Receive_Socket
(Socket : Socket_Type;
Item : out Ada.Streams.Stream_Element_Array;
- Last : out Ada.Streams.Stream_Element_Offset);
- -- Receive message from Socket. Last is the index value such that
- -- Item (Last) is the last character assigned. Note that Last is
- -- set to Item'First - 1 when the socket has been closed by
- -- peer. This is not an error and no exception is raised. Raise
- -- Socket_Error on error.
+ Last : out Ada.Streams.Stream_Element_Offset;
+ Flags : Request_Flag_Type := No_Request_Flag);
+ -- Receive message from Socket. Last is the index value such that Item
+ -- (Last) is the last character assigned. Note that Last is set to
+ -- Item'First - 1 when the socket has been closed by peer. This is not
+ -- an error, and no exception is raised in this case unless Item'First
+ -- is Stream_Element_Offset'First, in which case Constraint_Error is
+ -- raised. Flags allows to control the reception. Raise Socket_Error on
+ -- error.
procedure Receive_Socket
(Socket : Socket_Type;
Item : out Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset;
- From : out Sock_Addr_Type);
- -- Receive message from Socket. If Socket is not
- -- connection-oriented, the source address From of the message is
- -- filled in. Last is the index value such that Item (Last) is the
- -- last character assigned. Raise Socket_Error on error.
+ From : out Sock_Addr_Type;
+ Flags : Request_Flag_Type := No_Request_Flag);
+ -- Receive message from Socket. If Socket is not connection-oriented, the
+ -- source address From of the message is filled in. Last is the index
+ -- value such that Item (Last) is the last character assigned. Flags
+ -- allows to control the reception. Raises Socket_Error on error.
+
+ procedure Receive_Vector
+ (Socket : Socket_Type;
+ Vector : Vector_Type;
+ Count : out Ada.Streams.Stream_Element_Count;
+ Flags : Request_Flag_Type := No_Request_Flag);
+ -- Receive data from a socket and scatter it into the set of vector
+ -- elements Vector. Count is set to the count of received stream elements.
+ -- Flags allow control over reception.
function Resolve_Exception
- (Occurrence : Ada.Exceptions.Exception_Occurrence)
- return Error_Type;
- -- When Socket_Error or Host_Error are raised, the exception
- -- message contains the error code between brackets and a string
- -- describing the error code. Resolve_Error extracts the error
- -- code from an exception message and translate it into an
- -- enumeration value.
+ (Occurrence : Ada.Exceptions.Exception_Occurrence) return Error_Type;
+ -- When Socket_Error or Host_Error are raised, the exception message
+ -- contains the error code between brackets and a string describing the
+ -- error code. Resolve_Error extracts the error code from an exception
+ -- message and translate it into an enumeration value.
procedure Send_Socket
(Socket : Socket_Type;
Item : Ada.Streams.Stream_Element_Array;
- Last : out Ada.Streams.Stream_Element_Offset);
- -- Transmit a message to another socket. Note that Last is set to
- -- Item'First when socket has been closed by peer. This is not an
- -- error and no exception is raised. Raise Socket_Error on error;
+ Last : out Ada.Streams.Stream_Element_Offset;
+ To : access Sock_Addr_Type;
+ Flags : Request_Flag_Type := No_Request_Flag);
+ pragma Inline (Send_Socket);
+ -- Transmit a message over a socket. For a datagram socket, the address
+ -- is given by To.all. For a stream socket, To must be null. Last
+ -- is the index value such that Item (Last) is the last character
+ -- sent. Note that Last is set to Item'First - 1 if the socket has been
+ -- closed by the peer (unless Item'First is Stream_Element_Offset'First,
+ -- in which case Constraint_Error is raised instead). This is not an error,
+ -- and Socket_Error is not raised in that case. Flags allows control of the
+ -- transmission. Raises exception Socket_Error on error. Note: this
+ -- subprogram is inlined because it is also used to implement the two
+ -- variants below.
procedure Send_Socket
(Socket : Socket_Type;
Item : Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset;
- To : Sock_Addr_Type);
- -- Transmit a message to another socket. The address is given by
- -- To. Raise Socket_Error on error;
+ Flags : Request_Flag_Type := No_Request_Flag);
+ -- Transmit a message over a socket. Upon return, Last is set to the index
+ -- within Item of the last element transmitted. Flags allows to control
+ -- the transmission. Raises Socket_Error on any detected error condition.
+
+ procedure Send_Socket
+ (Socket : Socket_Type;
+ Item : Ada.Streams.Stream_Element_Array;
+ Last : out Ada.Streams.Stream_Element_Offset;
+ To : Sock_Addr_Type;
+ Flags : Request_Flag_Type := No_Request_Flag);
+ -- Transmit a message over a datagram socket. The destination address is
+ -- To. Flags allows to control the transmission. Raises Socket_Error on
+ -- error.
+
+ procedure Send_Vector
+ (Socket : Socket_Type;
+ Vector : Vector_Type;
+ Count : out Ada.Streams.Stream_Element_Count;
+ Flags : Request_Flag_Type := No_Request_Flag);
+ -- Transmit data gathered from the set of vector elements Vector to a
+ -- socket. Count is set to the count of transmitted stream elements. Flags
+ -- allow control over transmission.
procedure Set_Socket_Option
(Socket : Socket_Type;
Level : Level_Type := Socket_Level;
Option : Option_Type);
- -- Manipulate socket options. Raise Socket_Error on error.
+ -- Manipulate socket options. Raises Socket_Error on error
procedure Shutdown_Socket
(Socket : Socket_Type;
How : Shutmode_Type := Shut_Read_Write);
- -- Shutdown a connected socket. If How is Shut_Read, further
- -- receives will be disallowed. If How is Shut_Write, further
- -- sends will be disallowed. If how is Shut_Read_Write, further
- -- sends and receives will be disallowed.
+ -- Shutdown a connected socket. If How is Shut_Read further receives will
+ -- be disallowed. If How is Shut_Write further sends will be disallowed.
+ -- If How is Shut_Read_Write further sends and receives will be disallowed.
type Stream_Access is access all Ada.Streams.Root_Stream_Type'Class;
-- Same interface as Ada.Streams.Stream_IO
- function Stream
- (Socket : Socket_Type)
- return Stream_Access;
- -- Associate a stream with a stream-based socket that is already
- -- connected.
+ function Stream (Socket : Socket_Type) return Stream_Access;
+ -- Create a stream associated with an already connected stream-based socket
function Stream
(Socket : Socket_Type;
- Send_To : Sock_Addr_Type)
- return Stream_Access;
- -- Associate a stream with a datagram-based socket that is already
- -- bound. Send_To is the socket address to which messages are
- -- being sent.
+ Send_To : Sock_Addr_Type) return Stream_Access;
+ -- Create a stream associated with an already bound datagram-based socket.
+ -- Send_To is the destination address to which messages are being sent.
function Get_Address
- (Stream : Stream_Access)
- return Sock_Addr_Type;
- -- Return the socket address from which the last message was
- -- received.
-
- type Socket_Set_Type is private;
- -- This type allows to manipulate sets of sockets. It allows to
- -- wait for events on multiple endpoints at one time. This is an
- -- access type on a system dependent structure. To avoid memory
- -- leaks it is highly recommended to clean the access value with
- -- procedure Empty.
+ (Stream : not null Stream_Access) return Sock_Addr_Type;
+ -- Return the socket address from which the last message was received
+
+ procedure Free is new Ada.Unchecked_Deallocation
+ (Ada.Streams.Root_Stream_Type'Class, Stream_Access);
+ -- Destroy a stream created by one of the Stream functions above, releasing
+ -- the corresponding resources. The user is responsible for calling this
+ -- subprogram when the stream is not needed anymore.
+
+ type Socket_Set_Type is limited private;
+ -- This type allows to manipulate sets of sockets. It allows to wait for
+ -- events on multiple endpoints at one time. This type has default
+ -- initialization, and the default value is the empty set.
+ --
+ -- Note: This type used to contain a pointer to dynamically allocated
+ -- storage, but this is not the case anymore, and no special precautions
+ -- are required to avoid memory leaks.
procedure Clear (Item : in out Socket_Set_Type; Socket : Socket_Type);
-- Remove Socket from Item
- procedure Set (Item : in out Socket_Set_Type; Socket : Socket_Type);
- -- Insert Socket into Item
+ procedure Copy (Source : Socket_Set_Type; Target : out Socket_Set_Type);
+ -- Copy Source into Target as Socket_Set_Type is limited private
- procedure Empty (Item : in out Socket_Set_Type);
- -- Remove all Sockets from Item and deallocate internal data
+ procedure Empty (Item : out Socket_Set_Type);
+ -- Remove all Sockets from Item
- function Is_Empty
- (Item : Socket_Set_Type)
- return Boolean;
- -- Return True if Item is empty
+ procedure Get (Item : in out Socket_Set_Type; Socket : out Socket_Type);
+ -- Extract a Socket from socket set Item. Socket is set to
+ -- No_Socket when the set is empty.
+
+ function Is_Empty (Item : Socket_Set_Type) return Boolean;
+ -- Return True iff Item is empty
function Is_Set
(Item : Socket_Set_Type;
- Socket : Socket_Type)
- return Boolean;
- -- Return True if Socket is present in Item
-
- -- C select() waits for a number of file descriptors to change
- -- status. Usually, three independent sets of descriptors are
- -- watched (read, write and exception). A timeout gives an upper
- -- bound on the amount of time elapsed before select returns.
- -- This function blocks until an event occurs. On some platforms,
- -- C select can block the full process.
- --
- -- Check_Selector provides the very same behaviour. The only
- -- difference is that it does not watch for exception events. Note
- -- that on some platforms it is kept process blocking in purpose.
- -- The timeout parameter allows the user to have the behaviour he
- -- wants. Abort_Selector allows to abort safely a Check_Selector
- -- that is blocked forever. A special file descriptor is opened by
- -- Create_Selector and included in each call to
- -- Check_Selector. Abort_Selector causes an event to occur on this
- -- descriptor in order to unblock Check_Selector. The user must
- -- call Close_Selector to discard this special file. A reason to
- -- abort a select operation is typically to add a socket in one of
- -- the socket sets when the timeout is set to forever.
-
- Forever : constant Duration;
+ Socket : Socket_Type) return Boolean;
+ -- Return True iff Socket is present in Item
- type Selector_Type is limited private;
- type Selector_Access is access all Selector_Type;
+ procedure Set (Item : in out Socket_Set_Type; Socket : Socket_Type);
+ -- Insert Socket into Item
+
+ function Image (Item : Socket_Set_Type) return String;
+ -- Return a printable image of Item, for debugging purposes
+
+ -- The select(2) system call waits for events to occur on any of a set of
+ -- file descriptors. Usually, three independent sets of descriptors are
+ -- watched (read, write and exception). A timeout gives an upper bound
+ -- on the amount of time elapsed before select returns. This function
+ -- blocks until an event occurs. On some platforms, the select(2) system
+ -- can block the full process (not just the calling thread).
+ --
+ -- Check_Selector provides the very same behaviour. The only difference is
+ -- that it does not watch for exception events. Note that on some platforms
+ -- it is kept process blocking on purpose. The timeout parameter allows the
+ -- user to have the behaviour he wants. Abort_Selector allows to safely
+ -- abort a blocked Check_Selector call. A special socket is opened by
+ -- Create_Selector and included in each call to Check_Selector.
+ --
+ -- Abort_Selector causes an event to occur on this descriptor in order to
+ -- unblock Check_Selector. Note that each call to Abort_Selector will cause
+ -- exactly one call to Check_Selector to return with Aborted status. The
+ -- special socket created by Create_Selector is closed when Close_Selector
+ -- is called.
+ --
+ -- A typical case where it is useful to abort a Check_Selector operation is
+ -- the situation where a change to the monitored sockets set must be made.
procedure Create_Selector (Selector : out Selector_Type);
- -- Create a new selector
+ -- Initialize (open) a new selector
procedure Close_Selector (Selector : in out Selector_Type);
- -- Close Selector and all internal descriptors associated
+ -- Close Selector and all internal descriptors associated; deallocate any
+ -- associated resources. This subprogram may be called only when there is
+ -- no other task still using Selector (i.e. still executing Check_Selector
+ -- or Abort_Selector on this Selector). Has no effect if Selector is
+ -- already closed.
- type Selector_Status is (Completed, Expired, Aborted);
+ procedure Check_Selector
+ (Selector : Selector_Type;
+ R_Socket_Set : in out Socket_Set_Type;
+ W_Socket_Set : in out Socket_Set_Type;
+ Status : out Selector_Status;
+ Timeout : Selector_Duration := Forever);
+ -- Return when one Socket in R_Socket_Set has some data to be read or if
+ -- one Socket in W_Socket_Set is ready to transmit some data. In these
+ -- cases Status is set to Completed and sockets that are ready are set in
+ -- R_Socket_Set or W_Socket_Set. Status is set to Expired if no socket was
+ -- ready after a Timeout expiration. Status is set to Aborted if an abort
+ -- signal has been received while checking socket status.
+ --
+ -- Note that two different Socket_Set_Type objects must be passed as
+ -- R_Socket_Set and W_Socket_Set (even if they denote the same set of
+ -- Sockets), or some event may be lost.
+ --
+ -- Socket_Error is raised when the select(2) system call returns an error
+ -- condition, or when a read error occurs on the signalling socket used for
+ -- the implementation of Abort_Selector.
procedure Check_Selector
- (Selector : in out Selector_Type;
+ (Selector : Selector_Type;
R_Socket_Set : in out Socket_Set_Type;
W_Socket_Set : in out Socket_Set_Type;
+ E_Socket_Set : in out Socket_Set_Type;
Status : out Selector_Status;
- Timeout : Duration := Forever);
- -- Return when one Socket in R_Socket_Set has some data to be read
- -- or if one Socket in W_Socket_Set is ready to receive some
- -- data. In these cases Status is set to Completed and sockets
- -- that are ready are set in R_Socket_Set or W_Socket_Set. Status
- -- is set to Expired if no socket was ready after a Timeout
- -- expiration. Status is set to Aborted if an abort signal has been
- -- received while checking socket status. As this procedure
- -- returns when Timeout occurs, it is a design choice to keep this
- -- procedure process blocking. Note that a Timeout of 0.0 returns
- -- immediatly.
+ Timeout : Selector_Duration := Forever);
+ -- This refined version of Check_Selector allows watching for exception
+ -- events (i.e. notifications of out-of-band transmission and reception).
+ -- As above, all of R_Socket_Set, W_Socket_Set and E_Socket_Set must be
+ -- different objects.
procedure Abort_Selector (Selector : Selector_Type);
- -- Send an abort signal to the selector.
+ -- Send an abort signal to the selector. The Selector may not be the
+ -- Null_Selector.
+
+ type Fd_Set is private;
+ -- ??? This type must not be used directly, it needs to be visible because
+ -- it is used in the visible part of GNAT.Sockets.Thin_Common. This is
+ -- really an inversion of abstraction. The private part of GNAT.Sockets
+ -- needs to have visibility on this type, but since Thin_Common is a child
+ -- of Sockets, the type can't be declared there. The correct fix would
+ -- be to move the thin sockets binding outside of GNAT.Sockets altogether,
+ -- e.g. by renaming it to GNAT.Sockets_Thin.
private
type Socket_Type is new Integer;
No_Socket : constant Socket_Type := -1;
- Forever : constant Duration := Duration'Last;
+ -- A selector is either a null selector, which is always "open" and can
+ -- never be aborted, or a regular selector, which is created "closed",
+ -- becomes "open" when Create_Selector is called, and "closed" again when
+ -- Close_Selector is called.
+
+ type Selector_Type (Is_Null : Boolean := False) is limited record
+ case Is_Null is
+ when True =>
+ null;
- type Selector_Type is limited record
- R_Sig_Socket : Socket_Type;
- W_Sig_Socket : Socket_Type;
- In_Progress : Boolean := False;
+ when False =>
+ R_Sig_Socket : Socket_Type := No_Socket;
+ W_Sig_Socket : Socket_Type := No_Socket;
+ -- Signalling sockets used to abort a select operation
+
+ end case;
end record;
- -- The two signalling sockets are used to abort a select
- -- operation.
- type Socket_Set_Record;
- type Socket_Set_Type is access all Socket_Set_Record;
+ pragma Volatile (Selector_Type);
+
+ Null_Selector : constant Selector_Type := (Is_Null => True);
+
+ type Fd_Set is
+ new System.Storage_Elements.Storage_Array (1 .. SOSC.SIZEOF_fd_set);
+ for Fd_Set'Alignment use Interfaces.C.long'Alignment;
+ -- Set conservative alignment so that our Fd_Sets are always adequately
+ -- aligned for the underlying data type (which is implementation defined
+ -- and may be an array of C long integers).
+
+ type Fd_Set_Access is access all Fd_Set;
+ pragma Convention (C, Fd_Set_Access);
+ No_Fd_Set_Access : constant Fd_Set_Access := null;
+
+ type Socket_Set_Type is record
+ Last : Socket_Type := No_Socket;
+ -- Highest socket in set. Last = No_Socket denotes an empty set (which
+ -- is the default initial value).
+
+ Set : aliased Fd_Set;
+ -- Underlying socket set. Note that the contents of this component is
+ -- undefined if Last = No_Socket.
+ end record;
subtype Inet_Addr_Comp_Type is Natural range 0 .. 255;
-- Octet for Internet address
Any_Port : constant Port_Type := 0;
No_Port : constant Port_Type := 0;
- Any_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (others => 0));
- No_Inet_Addr : constant Inet_Addr_Type := (Family_Inet, (others => 0));
-
- No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
-
- Max_Host_Name_Length : constant := 64;
+ Any_Inet_Addr : constant Inet_Addr_Type :=
+ (Family_Inet, (others => 0));
+ No_Inet_Addr : constant Inet_Addr_Type :=
+ (Family_Inet, (others => 0));
+ Broadcast_Inet_Addr : constant Inet_Addr_Type :=
+ (Family_Inet, (others => 255));
+ Loopback_Inet_Addr : constant Inet_Addr_Type :=
+ (Family_Inet, (127, 0, 0, 1));
+
+ Unspecified_Group_Inet_Addr : constant Inet_Addr_Type :=
+ (Family_Inet, (224, 0, 0, 0));
+ All_Hosts_Group_Inet_Addr : constant Inet_Addr_Type :=
+ (Family_Inet, (224, 0, 0, 1));
+ All_Routers_Group_Inet_Addr : constant Inet_Addr_Type :=
+ (Family_Inet, (224, 0, 0, 2));
+
+ No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
+
+ Max_Name_Length : constant := 64;
-- The constant MAXHOSTNAMELEN is usually set to 64
- subtype Host_Name_Index is Natural range 1 .. Max_Host_Name_Length;
+ subtype Name_Index is Natural range 1 .. Max_Name_Length;
- type Host_Name_Type
- (Length : Host_Name_Index := Max_Host_Name_Length)
- is record
+ type Name_Type (Length : Name_Index := Max_Name_Length) is record
Name : String (1 .. Length);
end record;
-- We need fixed strings to avoid access types in host entry type
- type Host_Name_Array is array (Natural range <>) of Host_Name_Type;
+ type Name_Array is array (Natural range <>) of Name_Type;
type Inet_Addr_Array is array (Natural range <>) of Inet_Addr_Type;
type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is record
- Official : Host_Name_Type;
- Aliases : Host_Name_Array (1 .. Aliases_Length);
+ Official : Name_Type;
+ Aliases : Name_Array (1 .. Aliases_Length);
Addresses : Inet_Addr_Array (1 .. Addresses_Length);
end record;
+ type Service_Entry_Type (Aliases_Length : Natural) is record
+ Official : Name_Type;
+ Aliases : Name_Array (1 .. Aliases_Length);
+ Port : Port_Type;
+ Protocol : Name_Type;
+ end record;
+
+ type Request_Flag_Type is mod 2 ** 8;
+ No_Request_Flag : constant Request_Flag_Type := 0;
+ Process_Out_Of_Band_Data : constant Request_Flag_Type := 1;
+ Peek_At_Incoming_Data : constant Request_Flag_Type := 2;
+ Wait_For_A_Full_Reception : constant Request_Flag_Type := 4;
+ Send_End_Of_Record : constant Request_Flag_Type := 8;
+
end GNAT.Sockets;
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