1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- G N A T . S O C K E T S . T H I N . S I G N A L L I N G _ F D S --
9 -- Copyright (C) 2001-2006, AdaCore --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 -- Portable sockets-based implementation of GNAT.Sockets.Thin.Signalling_Fds
35 -- used for platforms that do not support UNIX pipes.
37 -- Note: this code used to be in GNAT.Sockets, but has been moved to a
38 -- platform-specific file. It is now used only for non-UNIX platforms.
42 package body Signalling_Fds is
48 function Create (Fds : not null access Fd_Pair) return C.int is
49 L_Sock, R_Sock, W_Sock : C.int := Failure;
50 -- Listening socket, read socket and write socket
52 Sin : aliased Sockaddr_In;
53 Len : aliased C.int := Sin'Size / 8;
54 -- Address of listening socket
57 -- Return status of system calls
63 Fds (Read_End) := Failure;
64 Fds (Write_End) := Failure;
66 -- We open two signalling sockets. One of them is used to send data
67 -- to the other, which is included in a C_Select socket set. The
68 -- communication is used to force the call to C_Select to complete,
69 -- and the waiting task to resume its execution.
71 -- Create a listening socket
73 L_Sock := C_Socket (Constants.AF_INET, Constants.SOCK_STREAM, 0);
75 if L_Sock = Failure then
79 -- Bind the socket to an available port on localhost
81 Sin.Sin_Addr.S_B1 := 127;
82 Sin.Sin_Addr.S_B2 := 0;
83 Sin.Sin_Addr.S_B3 := 0;
84 Sin.Sin_Addr.S_B4 := 1;
87 Res := C_Bind (L_Sock, Sin'Address, Len);
95 Res := C_Getsockname (L_Sock, Sin'Address, Len'Access);
100 -- Set socket to listen mode, with a backlog of 1 to guarantee that
101 -- exactly one call to connect(2) succeeds.
103 Res := C_Listen (L_Sock, 1);
105 if Res = Failure then
109 -- Create read end (client) socket
111 R_Sock := C_Socket (Constants.AF_INET, Constants.SOCK_STREAM, 0);
113 if R_Sock = Failure then
117 -- Connect listening socket
119 Res := C_Connect (R_Sock, Sin'Address, Len);
121 if Res = Failure then
125 -- Since the call to connect(2) has suceeded and the backlog limit on
126 -- the listening socket is 1, we know that there is now exactly one
127 -- pending connection on L_Sock, which is the one from R_Sock.
129 W_Sock := C_Accept (L_Sock, Sin'Address, Len'Access);
130 if W_Sock = Failure then
134 -- Set TCP_NODELAY on W_Sock, since we always want to send the data out
138 (Socket => Socket_Type (W_Sock),
139 Level => IP_Protocol_For_TCP_Level,
140 Option => (Name => No_Delay, Enabled => True));
142 -- Close listening socket (ignore exit status)
144 Res := C_Close (L_Sock);
146 Fds (Read_End) := R_Sock;
147 Fds (Write_End) := W_Sock;
154 if W_Sock /= Failure then
155 Res := C_Close (W_Sock);
158 if R_Sock /= Failure then
159 Res := C_Close (R_Sock);
162 if L_Sock /= Failure then
163 Res := C_Close (L_Sock);
166 Set_Socket_Errno (Err);
175 function Read (Rsig : C.int) return C.int is
176 Buf : aliased Character;
178 return C_Recv (Rsig, Buf'Address, 1, Constants.MSG_Forced_Flags);
185 function Write (Wsig : C.int) return C.int is
186 Buf : aliased Character := ASCII.NUL;
188 return C_Send (Wsig, Buf'Address, 1, Constants.MSG_Forced_Flags);