-- --
-- B o d y --
-- --
--- Copyright (C) 2001-2004 Ada Core Technologies, Inc. --
+-- Copyright (C) 2001-2005 Ada Core Technologies, Inc. --
-- --
-- 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 Interfaces.C.Strings;
-with GNAT.OS_Lib; use GNAT.OS_Lib;
with GNAT.Sockets.Constants;
with GNAT.Sockets.Thin; use GNAT.Sockets.Thin;
with GNAT.Task_Lock;
Err : Integer;
begin
- -- We open two signalling sockets. One of them is used to
- -- send data to the other, which is included in a C_Select
- -- socket set. The communication is used to force the call
- -- to C_Select to complete, and the waiting task to resume
- -- its execution.
+ -- We open two signalling sockets. One of them is used to send data to
+ -- send data to the other, which is included in a C_Select socket set.
+ -- The communication is used to force the call to C_Select to complete,
+ -- and the waiting task to resume its execution.
-- Create a listening socket
Raise_Socket_Error (Socket_Errno);
end if;
- -- Sin is already correctly initialized. Bind the socket to any
- -- unused port.
+ -- Bind the socket to any unused port on localhost
+
+ Sin.Sin_Addr.S_B1 := 127;
+ Sin.Sin_Addr.S_B2 := 0;
+ Sin.Sin_Addr.S_B3 := 0;
+ Sin.Sin_Addr.S_B4 := 1;
+ Sin.Sin_Port := 0;
Res := C_Bind (S0, Sin'Address, Len);
if Res = Failure then
Raise_Socket_Error (Err);
end if;
- Res := C_Listen (S0, 2);
+ -- Set backlog to 1 to guarantee that exactly one call to connect(2)
+ -- can succeed.
+
+ Res := C_Listen (S0, 1);
if Res = Failure then
Err := Socket_Errno;
Raise_Socket_Error (Err);
end if;
- -- Use INADDR_LOOPBACK
-
- Sin.Sin_Addr.S_B1 := 127;
- Sin.Sin_Addr.S_B2 := 0;
- Sin.Sin_Addr.S_B3 := 0;
- Sin.Sin_Addr.S_B4 := 1;
-
-- Do a connect and accept the connection
Res := C_Connect (S1, Sin'Address, Len);
Raise_Socket_Error (Err);
end if;
+ -- Since the call to connect(2) has suceeded and the backlog limit on
+ -- the listening socket is 1, we know that there is now exactly one
+ -- pending connection on S0, which is the one from S1.
+
S2 := C_Accept (S0, Sin'Address, Len'Access);
if S2 = Failure then
function Inet_Addr (Image : String) return Inet_Addr_Type is
use Interfaces.C.Strings;
- Img : chars_ptr := New_String (Image);
+ Img : chars_ptr;
Res : C.int;
- Err : Integer;
begin
+ -- Special case for the all-ones broadcast address: this address
+ -- has the same in_addr_t value as Failure, and thus cannot be
+ -- properly returned by inet_addr(3).
+
+ if Image (Image'Range) = "255.255.255.255" then
+ return Broadcast_Inet_Addr;
+ end if;
+
+ Img := New_String (Image);
Res := C_Inet_Addr (Img);
- Err := Errno;
Free (Img);
if Res = Failure then
- Raise_Socket_Error (Err);
+ Raise_Socket_Error (Constants.EINVAL);
end if;
return To_Inet_Addr (To_In_Addr (Res));
-- 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;
+ Any_Inet_Addr : constant Inet_Addr_Type;
+ No_Inet_Addr : constant Inet_Addr_Type;
+ Broadcast_Inet_Addr : constant Inet_Addr_Type;
type Sock_Addr_Type (Family : Family_Type := Family_Inet) is record
Addr : Inet_Addr_Type (Family);
procedure Set (Item : in out Socket_Set_Type; Socket : Socket_Type);
-- Insert Socket into 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.
+ -- 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 in purpose. The timeout parameter
+ -- 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
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 receive some data. In these
+ -- 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. 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
- -- immediately. Also note that two different objects must be passed as
- -- R_Socket_Set and W_Socket_Set (even if they contain the same set of
- -- Sockets), or some event will be lost.
+ -- immediately. Also 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 will 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;
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));
+ 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));
- No_Sock_Addr : constant Sock_Addr_Type := (Family_Inet, No_Inet_Addr, 0);
+ 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
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