Ada Programming/Libraries/GNAT.Sockets
Example
[edit | edit source]withAda.Text_IO;useAda.Text_IO;withGNAT.Sockets;useGNAT.Sockets;withAda.Streams;usetypeAda.Streams.Stream_Element_Count;procedureVcvisClient : Socket_Type; Address : Sock_Addr_Type; Channel : Stream_Access; Send : String := (1 => ASCII.CR, 2 => ASCII.LF, 3 => ASCII.CR, 4 => ASCII.LF); Offset : Ada.Streams.Stream_Element_Count; Data : Ada.Streams.Stream_Element_Array (1 .. 256);beginCreate_Socket (Client); Address.Addr := Inet_Addr("203.66.88.89"); Address.Port := 80; Connect_Socket (Client, Address); Channel := Stream (Client); String'Write (Channel, "GET / HTTP/1.1" & Send);loopAda.Streams.Read (Channel.All, Data, Offset);exitwhenOffset = 0;forIin1 .. OffsetloopAda.Text_IO.Put (Character'Val (Data (I)));endloop;endloop;endVcv;
Specification
[edit | edit source]------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- G N A T . S O C K E T S --
-- --
-- S p e c --
-- --
-- Copyright (C) 2001-2024, 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- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- 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. 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.
-- VxWorks cross ports fully implement this package
-- This package is not yet implemented on LynxOS or other cross ports
with Ada.Exceptions;
with Ada.Streams;
with Ada.Strings.Unbounded;
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 binding to 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.
-- 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 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
-- -- 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 := 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.
-- Create_Socket (Server);
-- -- 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
-- 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 Start;
-- Accept_Socket (Server, Socket, Address);
-- -- 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
-- declare
-- Message : String := String'Input (Channel);
-- begin
-- Ada.Text_IO.Put_Line (Message);
-- -- 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
-- Set_Socket_Option
-- (Socket,
-- Socket_Level,
-- (Reuse_Address, True));
-- -- 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
-- 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.
-- 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
-- declare
-- Message : String := String'Input (Channel);
-- begin
-- -- Get the address of the sender
-- Address := Get_Address (Channel);
-- Ada.Text_IO.Put_Line (Message & " from " & Image (Address));
-- -- 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
-- Address.Addr := Addresses (Get_Host_By_Name (Host_Name), 1);
-- Address.Port := 5876;
-- Create_Socket (Socket);
-- Set_Socket_Option
-- (Socket,
-- Socket_Level,
-- (Reuse_Address, True));
-- -- Force Ping 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
-- String'Output (Channel, "Hello world");
-- -- Force Ping to block
-- delay 0.2;
-- -- 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
-- 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,
-- (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
-- String'Output (Channel, "Hello world");
-- -- 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
-- Initialize;
-- Ping.Start;
-- Pong.Start;
-- Ping.Stop;
-- Pong.Stop;
-- Finalize;
-- end PingPong;
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.
use type Interfaces.C.int;
-- Need visibility on "-" operator so that we can write -1
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.
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 (struct timeval). Moreover, negative values are not allowed
-- to avoid system incompatibilities.
Immediate : constant Duration := 0.0;
Forever : constant Duration :=
Duration'Min
(Duration'Last,
(if SOSC."=" (SOSC.Target_OS, SOSC.Windows)
then Duration (2 ** 32 / 1000)
else 1.0 * SOSC.MAX_tv_sec));
-- Largest possible Duration that is also a valid value for the OS type
-- used for socket timeout.
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:
-- Completed: 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.
function Image (Socket : Socket_Type) return String;
-- Return a printable string for Socket
function To_Ada (Fd : Integer) return Socket_Type with Inline;
-- Convert a file descriptor to Socket_Type. This is useful when a socket
-- file descriptor is obtained from an external library call.
function To_C (Socket : Socket_Type) return Integer with Inline;
-- 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, Family_Unix, Family_Unspec);
-- Address family (or protocol family) identifies the communication domain
-- and groups protocols with similar address formats.
-- The order of the enumeration elements should not be changed unilaterally
-- because the IPv6_TCP_Preferred routine rely on it.
subtype Family_Inet_4_6 is Family_Type range Family_Inet .. Family_Inet6;
type Mode_Type is (Socket_Stream, Socket_Datagram, Socket_Raw);
-- Stream sockets provide connection-oriented byte streams. Datagram
-- sockets support unreliable connectionless message-based communication.
-- Raw sockets provide raw network-protocol access.
-- The order of the enumeration elements should not be changed unilaterally
-- because the IPv6_TCP_Preferred routine relies on it.
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). 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 range 0 .. 16#ffff#;
-- TCP/UDP port number
Any_Port : constant Port_Type;
-- All ports
No_Port : constant Port_Type;
-- Uninitialized port number
type Inet_Addr_Comp_Type is mod 2 ** 8;
-- Octet for Internet address
Inet_Addr_Bytes_Length : constant array (Family_Inet_4_6) of Natural :=
[Family_Inet => 4, Family_Inet6 => 16];
type Inet_Addr_Bytes is array (Natural range <>) of Inet_Addr_Comp_Type;
subtype Inet_Addr_V4_Type is
Inet_Addr_Bytes (1 .. Inet_Addr_Bytes_Length (Family_Inet));
subtype Inet_Addr_V6_Type is
Inet_Addr_Bytes (1 .. Inet_Addr_Bytes_Length (Family_Inet6));
subtype Inet_Addr_VN_Type is Inet_Addr_Bytes;
-- For backwards compatibility
type Inet_Addr_Type (Family : Family_Inet_4_6 := Family_Inet) is record
case Family is
when Family_Inet =>
Sin_V4 : Inet_Addr_V4_Type := [others => 0];
when Family_Inet6 =>
Sin_V6 : Inet_Addr_V6_Type := [others => 0];
end case;
end record;
-- An Internet address depends on an address family (IPv4 contains 4 octets
-- and IPv6 contains 16 octets).
Any_Inet_Addr : constant Inet_Addr_Type;
-- Wildcard enabling all addresses to use with bind
Any_Inet6_Addr : constant Inet_Addr_Type;
-- Idem for IPV6 socket
No_Inet_Addr : constant Inet_Addr_Type;
-- Uninitialized inet address
Broadcast_Inet_Addr : constant Inet_Addr_Type;
-- Broadcast destination address in the current network
Loopback_Inet_Addr : constant Inet_Addr_Type;
-- Loopback address to the local host
Loopback_Inet6_Addr : constant Inet_Addr_Type;
-- IPv6 Loopback address to the local host
-- Useful constants for multicast addresses
Unspecified_Group_Inet_Addr : constant Inet_Addr_Type;
-- IPv4 multicast mask with prefix length 4
Unspecified_Group_Inet6_Addr : constant Inet_Addr_Type;
-- IPv6 multicast mask with prefix length 16
All_Hosts_Group_Inet_Addr : constant Inet_Addr_Type;
-- Multicast group addresses all hosts on the same network segment
All_Hosts_Group_Inet6_Addr : constant Inet_Addr_Type;
-- Idem for IPv6 protocol
All_Routers_Group_Inet_Addr : constant Inet_Addr_Type;
-- Multicast group addresses all routers on the same network segment
All_Routers_Group_Inet6_Addr : constant Inet_Addr_Type;
-- Idem for IPv6 protocol
IPv4_To_IPv6_Prefix : constant Inet_Addr_Bytes :=
[1 .. 10 => 0, 11 .. 12 => 255];
-- Prefix for IPv4 mapped to IPv6 addresses
-- Functions to handle masks and prefixes
function Mask
(Family : Family_Inet_4_6;
Length : Natural;
Host : Boolean := False) return Inet_Addr_Type;
-- Return an address mask of the given family with the given prefix length.
-- If Host is False, this is a network mask (i.e. network bits are 1,
-- and host bits are 0); if Host is True, this is a host mask (i.e.
-- network bits are 0, and host bits are 1).
function "and" (Addr, Mask : Inet_Addr_Type) return Inet_Addr_Type;
function "or" (Net, Host : Inet_Addr_Type) return Inet_Addr_Type;
function "not" (Mask : Inet_Addr_Type) return Inet_Addr_Type;
-- Bit-wise operations on inet addresses (both operands must have the
-- same address family).
type Sock_Addr_Type (Family : Family_Type := Family_Inet) is record
case Family is
when Family_Unix =>
Name : Ada.Strings.Unbounded.Unbounded_String;
when Family_Inet_4_6 =>
Addr : Inet_Addr_Type (Family);
Port : Port_Type;
when Family_Unspec =>
null;
end case;
end record;
pragma No_Component_Reordering (Sock_Addr_Type);
-- 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;
-- Uninitialized socket address
function Is_IPv4_Address (Name : String) return Boolean;
-- Return true when Name is an IPv4 address in dotted quad notation
function Is_IPv6_Address (Name : String) return Boolean;
-- Return true when Name is an IPv6 address in numeric format
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
-- 8 hextets in hexadecimal format separated by colons.
function Image (Value : Sock_Addr_Type) return String;
-- Return socket address image. Network socket address image will be with
-- a port image separated by a colon.
function Inet_Addr (Image : String) return Inet_Addr_Type;
-- Convert address image from numbers-dots-and-colons notation into an
-- inet address.
function Unix_Socket_Address (Addr : String) return Sock_Addr_Type;
-- Convert unix local socket name to Sock_Addr_Type
function Network_Socket_Address
(Addr : Inet_Addr_Type; Port : Port_Type) return Sock_Addr_Type;
-- Create network socket address
-- 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;
function Official_Name (E : Host_Entry_Type) return String;
-- Return official name in host entry
function Aliases_Length (E : Host_Entry_Type) return Natural;
-- Return number of aliases in host entry
function Addresses_Length (E : Host_Entry_Type) return Natural;
-- 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
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
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 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. 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. 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
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.
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
(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,
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_IPv6_Level,
IP_Protocol_For_UDP_Level,
IP_Protocol_For_TCP_Level,
IP_Protocol_For_ICMP_Level,
IP_Protocol_For_IGMP_Level,
IP_Protocol_For_RAW_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. Each socket option is
-- provided with an appropriate C name taken from the sockets API comments.
-- The C name can be used to find a detailed description in the OS-specific
-- documentation. The options are grouped by main Level_Type value, which
-- can be used together with this option in calls to the Set_Socket_Option
-- and Get_Socket_Option routines. Note that some options can be used with
-- more than one level.
type Option_Name is
(Generic_Option,
-- Can be used to set/get any socket option via an OS-specific option
-- code with an integer value.
------------------
-- Socket_Level --
------------------
Keep_Alive, -- SO_KEEPALIVE
-- Enable sending of keep-alive messages on connection-oriented sockets
Reuse_Address, -- SO_REUSEADDR
-- Enable binding to an address and port already in use
Broadcast, -- SO_BROADCAST
-- Enable sending broadcast datagrams on the socket
Send_Buffer, -- SO_SNDBUF
-- Set/get the maximum socket send buffer in bytes
Receive_Buffer, -- SO_RCVBUF
-- Set/get the maximum socket receive buffer in bytes
Linger, -- SO_LINGER
-- When enabled, a Close_Socket or Shutdown_Socket will wait until all
-- queued messages for the socket have been successfully sent or the
-- linger timeout has been reached.
Error, -- SO_ERROR
-- Get and clear the pending socket error integer code
Send_Timeout, -- SO_SNDTIMEO
-- Specify sending timeout until reporting an error
Receive_Timeout, -- SO_RCVTIMEO
-- Specify receiving timeout until reporting an error
Busy_Polling, -- SO_BUSY_POLL
-- Sets the approximate time in microseconds to busy poll on a blocking
-- receive when there is no data.
Bind_To_Device, -- SO_BINDTODEVICE
-- Bind to a specific NIC (Network Interface Controller)
-------------------------------
-- IP_Protocol_For_TCP_Level --
-------------------------------
No_Delay, -- TCP_NODELAY
-- Disable the Nagle algorithm. This means that output buffer content
-- is always sent as soon as possible, even if there is only a small
-- amount of data.
Keep_Alive_Count, -- TCP_KEEPCNT
-- Maximum number of keepalive probes
Keep_Alive_Idle, -- TCP_KEEPIDLE
-- Idle time before TCP starts sending keepalive probes
Keep_Alive_Interval, -- TCP_KEEPINTVL
-- Time between individual keepalive probes
------------------------------
-- IP_Protocol_For_IP_Level --
------------------------------
Add_Membership_V4, -- IP_ADD_MEMBERSHIP
-- Join a multicast group
Drop_Membership_V4, -- IP_DROP_MEMBERSHIP
-- Leave a multicast group
Multicast_If_V4, -- IP_MULTICAST_IF
-- Set/Get outgoing interface for sending multicast packets
Multicast_Loop_V4, -- IP_MULTICAST_LOOP
-- This boolean option determines whether sent multicast packets should
-- be looped back to the local sockets.
Multicast_TTL, -- IP_MULTICAST_TTL
-- Set/Get the time-to-live of sent multicast packets
Receive_Packet_Info, -- IP_PKTINFO
-- Receive low-level packet info as ancillary data
--------------------------------
-- IP_Protocol_For_IPv6_Level --
--------------------------------
Add_Membership_V6, -- IPV6_ADD_MEMBERSHIP
-- Join IPv6 multicast group
Drop_Membership_V6, -- IPV6_DROP_MEMBERSHIP
-- Leave IPv6 multicast group
Multicast_If_V6, -- IPV6_MULTICAST_IF
-- Set/Get outgoing interface index for sending multicast packets
Multicast_Loop_V6, -- IPV6_MULTICAST_LOOP
-- This boolean option determines whether sent multicast IPv6 packets
-- should be looped back to the local sockets.
IPv6_Only, -- IPV6_V6ONLY
-- Restricted to IPv6 communications only
Multicast_Hops -- IPV6_MULTICAST_HOPS
-- Set the multicast hop limit for the IPv6 socket
);
subtype Specific_Option_Name is
Option_Name range Keep_Alive .. Option_Name'Last;
Add_Membership : Option_Name renames Add_Membership_V4;
Drop_Membership : Option_Name renames Drop_Membership_V4;
Multicast_If : Option_Name renames Multicast_If_V4;
Multicast_Loop : Option_Name renames Multicast_Loop_V4;
type Option_Type (Name : Option_Name := Keep_Alive) is record
case Name is
when Generic_Option =>
Optname : Interfaces.C.int := -1;
Optval : Interfaces.C.int;
when Keep_Alive |
Reuse_Address |
Broadcast |
Linger |
No_Delay |
Receive_Packet_Info |
IPv6_Only |
Multicast_Loop_V4 |
Multicast_Loop_V6 =>
Enabled : Boolean;
case Name is
when Linger =>
Seconds : Natural;
when others =>
null;
end case;
when Keep_Alive_Count =>
Count : Natural;
when Keep_Alive_Idle =>
Idle_Seconds : Natural;
when Keep_Alive_Interval =>
Interval_Seconds : Natural;
when Busy_Polling =>
Microseconds : Natural;
when Send_Buffer |
Receive_Buffer =>
Size : Natural;
when Error =>
Error : Error_Type;
when Add_Membership_V4 |
Add_Membership_V6 |
Drop_Membership_V4 |
Drop_Membership_V6 =>
Multicast_Address : Inet_Addr_Type;
case Name is
when Add_Membership_V4 |
Drop_Membership_V4 =>
Local_Interface : Inet_Addr_Type;
when others =>
Interface_Index : Natural;
end case;
when Multicast_If_V4 =>
Outgoing_If : Inet_Addr_Type;
when Multicast_If_V6 =>
Outgoing_If_Index : Natural;
when Multicast_TTL =>
Time_To_Live : Natural;
when Multicast_Hops =>
Hop_Limit : Integer range -1 .. 255;
when Send_Timeout |
Receive_Timeout =>
Timeout : Timeval_Duration;
when Bind_To_Device =>
Device : Ada.Strings.Unbounded.Unbounded_String;
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.
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
case Name is
when Non_Blocking_IO =>
Enabled : Boolean;
when N_Bytes_To_Read =>
Size : Natural;
end case;
end record;
-- A request flag allows specification of 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 : Interfaces.C.size_t;
end record;
type Vector_Type is array (Integer range <>) of Vector_Element;
type Address_Info is record
Addr : Sock_Addr_Type;
Mode : Mode_Type := Socket_Stream;
Level : Level_Type := IP_Protocol_For_IP_Level;
end record;
type Address_Info_Array is array (Positive range <>) of Address_Info;
function Get_Address_Info
(Host : String;
Service : String;
Family : Family_Type := Family_Unspec;
Mode : Mode_Type := Socket_Stream;
Level : Level_Type := IP_Protocol_For_IP_Level;
Numeric_Host : Boolean := False;
Passive : Boolean := False;
Unknown : access procedure
(Family, Mode, Level, Length : Integer) := null)
return Address_Info_Array;
-- Returns available addresses for the Host and Service names.
-- If Family is Family_Unspec, all available protocol families returned.
-- Service is the name of service as defined in /etc/services or port
-- number in string representation.
-- If Unknown procedure access specified it will be called in case of
-- unknown family found.
-- Numeric_Host flag suppresses any potentially lengthy network host
-- address lookups, and Host have to represent numerical network address in
-- this case.
-- If Passive is True and Host is empty then the returned socket addresses
-- will be suitable for binding a socket that will accept connections.
-- The returned socket address will contain the "wildcard address".
-- The wildcard address is used by applications (typically servers) that
-- intend to accept connections on any of the hosts's network addresses.
-- If Host is not empty, then the Passive flag is ignored.
-- If Passive is False, then the returned socket addresses will be suitable
-- for use with connect, sendto, or sendmsg. If Host is empty, then the
-- network address will be set to the loopback interface address;
-- this is used by applications that intend to communicate with peers
-- running on the same host.
procedure Sort
(Addr_Info : in out Address_Info_Array;
Compare : access function (Left, Right : Address_Info) return Boolean);
-- Sort address info array in order defined by compare function
function IPv6_TCP_Preferred (Left, Right : Address_Info) return Boolean;
-- To use with Sort to order where IPv6 and TCP addresses first
type Host_Service (Host_Length, Service_Length : Natural) is record
Host : String (1 .. Host_Length);
Service : String (1 .. Service_Length);
end record;
function Get_Name_Info
(Addr : Sock_Addr_Type;
Numeric_Host : Boolean := False;
Numeric_Serv : Boolean := False) return Host_Service;
-- Returns host and service names by the address and port.
-- If Numeric_Host is True, then the numeric form of the hostname is
-- returned. When Numeric_Host is False, this will still happen in case the
-- host name cannot be determined.
-- If Numenric_Serv is True, then the numeric form of the service address
-- (port number) is returned. When Numenric_Serv is False, this will still
-- happen in case the service's name cannot be determined.
procedure Create_Socket
(Socket : out Socket_Type;
Family : Family_Type := Family_Inet;
Mode : Mode_Type := Socket_Stream;
Level : Level_Type := IP_Protocol_For_IP_Level);
-- Create an endpoint for communication. Raises Socket_Error on error
procedure Create_Socket_Pair
(Left : out Socket_Type;
Right : out Socket_Type;
Family : Family_Type := Family_Unspec;
Mode : Mode_Type := Socket_Stream;
Level : Level_Type := IP_Protocol_For_IP_Level);
-- Create two connected sockets. Raises Socket_Error on error.
-- If Family is unspecified, it creates Family_Unix sockets on UNIX and
-- Family_Inet sockets on non UNIX platforms.
procedure Accept_Socket
(Server : Socket_Type;
Socket : out Socket_Type;
Address : out Sock_Addr_Type);
-- 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. Note: if Server is a non-blocking socket, whether or not this
-- aspect is inherited by Socket is platform-dependent.
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;
Address : Sock_Addr_Type);
-- Once a socket is created, assign a local address to it. Raise
-- Socket_Error on error.
procedure Close_Socket (Socket : Socket_Type);
-- Close a socket and more specifically a non-connected socket
procedure Connect_Socket
(Socket : Socket_Type;
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. If Timeout is 0.0,
-- no attempt is made to detect whether the connection has succeeded; it
-- is up to the user to determine this using Check_Selector later on.
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 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. Return
-- No_Sock_Addr on error (e.g. socket closed or not locally bound).
function Get_Socket_Option
(Socket : Socket_Type;
Level : Level_Type;
Name : Option_Name;
Optname : Interfaces.C.int := -1) return Option_Type;
-- Get the options associated with a socket. Raises Socket_Error on error.
-- Optname identifies specific option when Name is Generic_Option.
procedure Listen_Socket
(Socket : Socket_Type;
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;
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 control of 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;
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 control of 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.
procedure Send_Socket
(Socket : Socket_Type;
Item : Ada.Streams.Stream_Element_Array;
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;
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 control of
-- 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 control of 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_Close_On_Exec
(Socket : Socket_Type;
Close_On_Exec : Boolean;
Status : out Boolean);
-- When Close_On_Exec is True, mark Socket to be closed automatically when
-- a new program is executed by the calling process (i.e. prevent Socket
-- from being inherited by child processes). When Close_On_Exec is False,
-- mark Socket to not be closed on exec (i.e. allow it to be inherited).
-- Status is False if the operation could not be performed, or is not
-- supported on the target platform.
procedure Set_Socket_Option
(Socket : Socket_Type;
Level : Level_Type;
Option : Option_Type);
-- 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.
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;
-- Create a stream associated with a connected stream-based socket.
-- Note: keep in mind that the default stream attributes for composite
-- types perform separate Read/Write operations for each component,
-- recursively. If performance is an issue, you may want to consider
-- introducing a buffering stage.
function Stream
(Socket : Socket_Type;
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 : 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 manipulation of sets of sockets. It allows waiting
-- 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 Copy (Source : Socket_Set_Type; Target : out Socket_Set_Type);
-- Copy Source into Target as Socket_Set_Type is limited private
procedure Empty (Item : out Socket_Set_Type);
-- Remove all Sockets from Item
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 iff Socket is present in Item
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 behavior. 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 behavior he wants. Abort_Selector allows the safe
-- abort of 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);
-- Initialize (open) a new selector
procedure Close_Selector (Selector : in out Selector_Type);
-- 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.
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. Also keep in mind that this
-- procedure modifies the passed socket sets to indicate which sockets
-- actually had events upon return. The socket set therefore has to
-- be reset by the caller for further calls.
--
-- 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 : 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 : 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. 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
package ASU renames Ada.Strings.Unbounded;
type Socket_Type is new Integer;
No_Socket : constant Socket_Type := -1;
-- 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;
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;
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;
Any_Port : constant Port_Type := 0;
No_Port : constant Port_Type := 0;
Any_Inet_Addr : constant Inet_Addr_Type :=
(Family_Inet, [others => 0]);
Any_Inet6_Addr : constant Inet_Addr_Type :=
(Family_Inet6, [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]);
Loopback_Inet6_Addr : constant Inet_Addr_Type :=
(Family_Inet6,
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 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]);
Unspecified_Group_Inet6_Addr : constant Inet_Addr_Type :=
(Family_Inet6, [255, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]);
All_Hosts_Group_Inet6_Addr : constant Inet_Addr_Type :=
(Family_Inet6, [255, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]);
All_Routers_Group_Inet6_Addr : constant Inet_Addr_Type :=
(Family_Inet6, [255, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2]);
No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
Max_Name_Length : constant := SOSC.NI_MAXHOST;
-- Most systems don't provide constants that specify the maximum size
-- of either a FQDN or a service name. In order to aid applications in
-- allocating buffers, the constant NI_MAXHOST is defined in <netdb.h>.
subtype Name_Index is Natural range 1 .. Max_Name_Length;
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 Name_Array is array (Positive range <>) of Name_Type;
type Inet_Addr_Array is array (Positive range <>) of Inet_Addr_Type;
type Host_Entry_Type (Aliases_Length, Addresses_Length : Natural) is record
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;
Port : Port_Type;
Protocol : Name_Type;
Aliases : Name_Array (1 .. Aliases_Length);
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;
procedure Raise_Socket_Error (Error : Integer) with No_Return;
-- Raise Socket_Error with an exception message describing the error code
-- from errno.
end GNAT.Sockets;
See also
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