-- --
-- S p e c --
-- --
--- Copyright (C) 2001-2008, AdaCore --
+-- 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- --
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
-- 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.
+
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,
- "passing a parameter to Initialize is not supported anymore");
+ (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-- for compatibility reasons, but this interface is obsolete (and if the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,
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 := 0.0;
- Forever : constant := Duration (Integer'Last) * 1.0;
- -- Should be Duration 2 ** (Constants.SIZEOF_tv_sec * 8 - 1) - 1 ???
+ 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;
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.
+ -- and groups protocols with similar address formats.
type Mode_Type is (Socket_Stream, Socket_Datagram);
-- Stream sockets provide connection-oriented byte streams. Datagram
-- 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
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
+
+ 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);
-- 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,
Connection_Timed_Out,
Too_Many_References,
Resource_Temporarily_Unavailable,
+ Broken_Pipe,
Unknown_Host,
Host_Name_Lookup_Failure,
Non_Recoverable_Error,
-- 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);
+ 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_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
-- 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
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 successully, timed out, or was aborted. If Selector
+ -- 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.
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 successully, timed out, or was aborted.
+ -- 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.
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. Flags allows to control the
- -- reception. Raise Socket_Error on error.
+ -- 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;
procedure Receive_Vector
(Socket : Socket_Type;
Vector : Vector_Type;
- Count : out Ada.Streams.Stream_Element_Count);
+ 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;
(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 to another socket. Note that Last is set to
- -- Item'First-1 when socket has been closed by peer. This is not
- -- considered an error and no exception is raised. Flags allows to control
- -- the transmission. Raises Socket_Error on any other error condition.
+ -- 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;
Last : out Ada.Streams.Stream_Element_Offset;
To : Sock_Addr_Type;
Flags : Request_Flag_Type := No_Request_Flag);
- -- Transmit a message to another socket. The address is given by To. Flags
- -- allows to control the transmission. Raises Socket_Error on error.
+ -- 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);
+ 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.
+ -- socket. Count is set to the count of transmitted stream elements. Flags
+ -- allow control over transmission.
procedure Set_Socket_Option
(Socket : Socket_Type;
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;
- -- Create a stream associated with a stream-based socket that is
- -- already connected.
+ -- Create a stream associated with an already connected stream-based socket
function Stream
(Socket : Socket_Type;
Send_To : Sock_Addr_Type) return Stream_Access;
- -- Create a stream associated with a datagram-based socket that is already
- -- bound. Send_To is the socket address to which messages are being sent.
+ -- 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;
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.
+ -- 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 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.
+ -- 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 : in out Socket_Set_Type);
+ 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
procedure Get (Item : in out Socket_Set_Type; Socket : out Socket_Type);
-- Extract a Socket from socket set Item. Socket is set to
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
-- 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 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.
+ -- 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; 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).
+ -- or Abort_Selector on this Selector). Has no effect if Selector is
+ -- already closed.
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;
Status : out Selector_Status;
-- 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.
+ --
+ -- 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 : Selector_Duration := Forever);
- -- This refined version of Check_Selector allows to watch for exception
- -- events (that is 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.
+ -- 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_Access is private;
- No_Fd_Set_Access : constant Fd_Set_Access;
+ 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 Sokcets, the type can't be declared there. The correct fix would
+ -- 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.
type Socket_Type is new Integer;
No_Socket : constant Socket_Type := -1;
- type Selector_Type is limited record
- R_Sig_Socket : Socket_Type := No_Socket;
- W_Sig_Socket : Socket_Type := No_Socket;
- -- Signalling sockets used to abort a select operation
+ -- 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);
- type Fd_Set is null record;
+ 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;
- Set : Fd_Set_Access;
+ 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;
(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);
subtype Name_Index is Natural range 1 .. Max_Name_Length;
- type Name_Type
- (Length : Name_Index := Max_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
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