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[Ada] New routine GNAT.Sockets.Create_Socket_Pair 

New routine to create 2 connected sockets. This routine is analog of the
UNIX system call socketpair. On UNIX platforms it is implemented on the
base of socketpair. On other platforms it is implemented by conecting
network sockets over loopback interface.

2019-09-19  Dmitriy Anisimkov  <anisimko@adacore.com>

gcc/ada/

	* libgnat/g-socket.ads, libgnat/g-socket.adb
	(Create_Socket_Pair): New routine.
	* libgnat/g-socthi.ads (OS_Has_Socketpair): Boolean constant.
	(C_Socketpair): New imported routine.
	* libgnat/g-socthi__mingw.ads, libgnat/g-socthi__vxworks.ads
	(Default_Socket_Pair_Family): New constant.
	(C_Socketpair): New routine.
	* libgnat/g-socthi__mingw.adb, libgnat/g-socthi__vxworks.adb
	(C_Socketpair): Is separated in anouther file.
	* libgnat/g-sthcso.adb (C_Socketpair): Non UNIX implementation.
	* libgnat/g-stsifd__sockets.adb: Reuse C_Socketpair.

From-SVN: r275951
This commit is contained in:
Dmitriy Anisimkov 2019-09-19 08:14:18 +00:00 committed by Pierre-Marie de Rodat
parent 4fe56329e0
commit fd0d7b4e3b
10 changed files with 329 additions and 145 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
gcc/ada/ChangeLog
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@ -1,3 +1,17 @@
2019-09-19 Dmitriy Anisimkov <anisimko@adacore.com>
* libgnat/g-socket.ads, libgnat/g-socket.adb
(Create_Socket_Pair): New routine.
* libgnat/g-socthi.ads (OS_Has_Socketpair): Boolean constant.
(C_Socketpair): New imported routine.
* libgnat/g-socthi__mingw.ads, libgnat/g-socthi__vxworks.ads
(Default_Socket_Pair_Family): New constant.
(C_Socketpair): New routine.
* libgnat/g-socthi__mingw.adb, libgnat/g-socthi__vxworks.adb
(C_Socketpair): Is separated in anouther file.
* libgnat/g-sthcso.adb (C_Socketpair): Non UNIX implementation.
* libgnat/g-stsifd__sockets.adb: Reuse C_Socketpair.
2019-09-19 Yannick Moy <moy@adacore.com>
* sem_prag.adb (Analyze_Depends_In_Decl_Part): Simplify previous

28
gcc/ada/libgnat/g-socket.adb
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@ -867,6 +867,34 @@ package body GNAT.Sockets is
Socket := Socket_Type (Res);
end Create_Socket;
------------------------
-- Create_Socket_Pair --
------------------------
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)
is
Res : C.int;
Pair : aliased Thin_Common.Fd_Pair;
begin
Res := C_Socketpair
((if Family = Family_Unspec then Default_Socket_Pair_Family
else Families (Family)),
Modes (Mode), Levels (Level), Pair'Access);
if Res = Failure then
Raise_Socket_Error (Socket_Errno);
end if;
Left := Socket_Type (Pair (Pair'First));
Right := Socket_Type (Pair (Pair'Last));
end Create_Socket_Pair;
-----------
-- Empty --
-----------

12
gcc/ada/libgnat/g-socket.ads
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@ -1104,7 +1104,17 @@ package GNAT.Sockets is
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
-- 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;

11
gcc/ada/libgnat/g-socthi.ads
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@ -184,6 +184,16 @@ package GNAT.Sockets.Thin is
function C_System
(Command : System.Address) return C.int;
Default_Socket_Pair_Family : constant := SOSC.AF_UNIX;
-- UNIX has socketpair system call and AF_UNIX family is widely supported
function C_Socketpair
(Domain : C.int;
Typ : C.int;
Protocol : C.int;
Fds : not null access Fd_Pair) return C.int;
-- Creates pair of connected sockets
-------------------------------------------------------
-- Signalling file descriptors for selector abortion --
-------------------------------------------------------
@ -249,6 +259,7 @@ private
pragma Import (C, C_Select, "select");
pragma Import (C, C_Setsockopt, "setsockopt");
pragma Import (C, C_Shutdown, "shutdown");
pragma Import (C, C_Socketpair, "socketpair");
pragma Import (C, C_System, "system");
pragma Import (C, Nonreentrant_Gethostbyname, "gethostbyname");

10
gcc/ada/libgnat/g-socthi__mingw.adb
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@ -511,6 +511,16 @@ package body GNAT.Sockets.Thin is
return System.CRTL.ssize_t (Count);
end C_Sendmsg;
------------------
-- C_Socketpair --
------------------
function C_Socketpair
(Domain : C.int;
Typ : C.int;
Protocol : C.int;
Fds : not null access Fd_Pair) return C.int is separate;
--------------
-- Finalize --
--------------

11
gcc/ada/libgnat/g-socthi__mingw.ads
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@ -177,6 +177,17 @@ package GNAT.Sockets.Thin is
Typ : C.int;
Protocol : C.int) return C.int;
Default_Socket_Pair_Family : constant := SOSC.AF_INET;
-- Windows has not socketpair system call, and C_Socketpair below is
-- implemented on loopback connected network sockets.
function C_Socketpair
(Domain : C.int;
Typ : C.int;
Protocol : C.int;
Fds : not null access Fd_Pair) return C.int;
-- Creates pair of connected sockets
function C_System
(Command : System.Address) return C.int;

10
gcc/ada/libgnat/g-socthi__vxworks.adb
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@ -419,6 +419,16 @@ package body GNAT.Sockets.Thin is
return R;
end C_Socket;
------------------
-- C_Socketpair --
------------------
function C_Socketpair
(Domain : C.int;
Typ : C.int;
Protocol : C.int;
Fds : not null access Fd_Pair) return C.int is separate;
--------------
-- Finalize --
--------------

11
gcc/ada/libgnat/g-socthi__vxworks.ads
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@ -178,6 +178,17 @@ package GNAT.Sockets.Thin is
Typ : C.int;
Protocol : C.int) return C.int;
Default_Socket_Pair_Family : constant := SOSC.AF_INET;
-- VxWorks has not socketpair system call, and C_Socketpair below is
-- implemented on loopback connected network sockets.
function C_Socketpair
(Domain : C.int;
Typ : C.int;
Protocol : C.int;
Fds : not null access Fd_Pair) return C.int;
-- Creates pair of connected sockets
function C_System
(Command : System.Address) return C.int;

213
gcc/ada/libgnat/g-sthcso.adb Normal file
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@ -0,0 +1,213 @@
------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- G N A T . S O C K E T S . T H I N . C _ S O C K E T P A I R --
-- --
-- B o d y --
-- --
-- Copyright (C) 2001-2019, 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. --
-- --
------------------------------------------------------------------------------
-- Portable sockets-based implementation of the C_Socketpair used for
-- platforms that do not support UNIX socketpair system call.
-- Note: this code is only for non-UNIX platforms.
separate (GNAT.Sockets.Thin)
function C_Socketpair
(Domain : C.int;
Typ : C.int;
Protocol : C.int;
Fds : not null access Fd_Pair) return C.int
is
use type C.char_array;
L_Sock, C_Sock, P_Sock : C.int := Failure;
-- Listening socket, client socket and peer socket
Family : constant Family_Type :=
(case Domain is
when SOSC.AF_INET => Family_Inet,
when SOSC.AF_INET6 => Family_Inet6,
when others => Family_Unspec);
Len : aliased C.int := C.int (Lengths (Family));
C_Sin : aliased Sockaddr;
C_Bin : aliased C.char_array (1 .. C.size_t (Len));
for C_Bin'Address use C_Sin'Address;
-- Address of listening and client socket and it's binary representation.
-- We need binary representation because Ada does not allow to compare
-- unchecked union if either of the operands lacks inferable discriminants.
-- RM-B-3-3 23/2.
P_Sin : aliased Sockaddr;
P_Bin : aliased C.char_array (1 .. C.size_t (Len));
for P_Bin'Address use P_Sin'Address;
-- Address of peer socket and it's binary representation
T_Sin : aliased Sockaddr;
T_Bin : aliased C.char_array (1 .. C.size_t (Len));
for T_Bin'Address use T_Sin'Address;
-- Temporary address to compare and check that address and port of the
-- socket equal to peer address and port of the opposite connected socket.
Res : C.int with Warnings => Off;
begin
Set_Family (C_Sin.Sin_Family, Family);
case Family is
when Family_Inet =>
C_Sin.Sin_Addr.S_B1 := 127;
C_Sin.Sin_Addr.S_B4 := 1;
when Family_Inet6 =>
C_Sin.Sin6_Addr (C_Sin.Sin6_Addr'Last) := 1;
when others =>
Set_Socket_Errno (SOSC.EAFNOSUPPORT);
return Failure;
end case;
for J in 1 .. 10 loop
-- Retry loop, in case the C_Connect below fails
C_Sin.Sin_Port := 0;
-- Create a listening socket
L_Sock := C_Socket (Domain, Typ, Protocol);
exit when L_Sock = Failure;
-- Bind the socket to an available port on localhost
Res := C_Bind (L_Sock, C_Sin'Address, Len);
exit when Res = Failure;
-- Get assigned port
Res := C_Getsockname (L_Sock, C_Sin'Address, Len'Access);
exit when Res = Failure;
-- Set socket to listen mode, with a backlog of 1 to guarantee that
-- exactly one call to connect(2) succeeds.
Res := C_Listen (L_Sock, 1);
exit when Res = Failure;
-- Create read end (client) socket
C_Sock := C_Socket (Domain, Typ, Protocol);
exit when C_Sock = Failure;
-- Connect listening socket
Res := C_Connect (C_Sock, C_Sin'Address, Len);
if Res = Failure then
-- In rare cases, the above C_Bind chooses a port that is still
-- marked "in use", even though it has been closed (perhaps by some
-- other process that has already exited). This causes the above
-- C_Connect to fail with EADDRINUSE. In this case, we close the
-- ports, and loop back to try again. This mysterious Windows
-- behavior is documented. See, for example:
-- http://msdn2.microsoft.com/en-us/library/ms737625.aspx
-- In an experiment with 2000 calls, 21 required exactly one retry, 7
-- required two, and none required three or more. Note that no delay
-- is needed between retries; retrying C_Bind will typically produce
-- a different port.
exit when Socket_Errno /= SOSC.EADDRINUSE;
goto Repeat;
end if;
-- Since the call to connect(2) has succeeded and the backlog limit
-- on the listening socket is 1, we know that there is now exactly
-- one pending connection on L_Sock, which is the one from R_Sock.
P_Sin.Sun_Path := (others => C.nul);
P_Sock := C_Accept (L_Sock, P_Sin'Address, Len'Access);
exit when P_Sock = Failure;
-- Address and port of the socket equal to peer address and port of the
-- opposite connected socket.
Res := C_Getsockname (P_Sock, T_Sin'Address, Len'Access);
exit when Res = Failure;
if T_Bin /= C_Bin then
goto Repeat;
end if;
-- Address and port of the socket equal to peer address and port of the
-- opposite connected socket.
Res := C_Getsockname (C_Sock, T_Sin'Address, Len'Access);
exit when Res = Failure;
if T_Bin /= P_Bin then
goto Repeat;
end if;
-- Close listening socket (ignore exit status)
Res := C_Close (L_Sock);
Fds.all := (Read_End => C_Sock, Write_End => P_Sock);
return Thin_Common.Success;
<<Repeat>>
Res := C_Close (C_Sock);
C_Sock := Failure;
Res := C_Close (P_Sock);
P_Sock := Failure;
Res := C_Close (L_Sock);
L_Sock := Failure;
end loop;
declare
Saved_Errno : constant Integer := Socket_Errno;
begin
if P_Sock /= Failure then
Res := C_Close (P_Sock);
end if;
if C_Sock /= Failure then
Res := C_Close (C_Sock);
end if;
if L_Sock /= Failure then
Res := C_Close (L_Sock);
end if;
Set_Socket_Errno (Saved_Errno);
end;
return Failure;
end C_Socketpair;

154
gcc/ada/libgnat/g-stsifd__sockets.adb
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@ -57,154 +57,20 @@ package body Signalling_Fds is
------------
function Create (Fds : not null access Fd_Pair) return C.int is
L_Sock, R_Sock, W_Sock : C.int := Failure;
-- Listening socket, read socket and write socket
Sin : aliased Sockaddr;
Len : aliased C.int;
-- Address of listening socket
Res : C.int;
pragma Warnings (Off, Res);
-- Return status of system calls (usually ignored, hence warnings off)
Res : constant C.int :=
C_Socketpair (SOSC.AF_INET, SOSC.SOCK_STREAM, 0, Fds);
begin
Fds.all := (Read_End | Write_End => Failure);
if Res /= Failure then
-- Set TCP_NODELAY on Fds (Write_End), since we always want to send
-- the data out immediately.
-- 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.
loop
-- Retry loop, in case the C_Connect below fails
-- Create a listening socket
L_Sock := C_Socket (SOSC.AF_INET, SOSC.SOCK_STREAM, 0);
if L_Sock = Failure then
goto Fail;
end if;
-- Bind the socket to an available port on localhost
Set_Family (Sin.Sin_Family, Family_Inet);
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;
Len := C.int (Lengths (Family_Inet));
Res := C_Bind (L_Sock, Sin'Address, Len);
if Res = Failure then
goto Fail;
end if;
-- Get assigned port
Res := C_Getsockname (L_Sock, Sin'Address, Len'Access);
if Res = Failure then
goto Fail;
end if;
-- Set socket to listen mode, with a backlog of 1 to guarantee that
-- exactly one call to connect(2) succeeds.
Res := C_Listen (L_Sock, 1);
if Res = Failure then
goto Fail;
end if;
-- Create read end (client) socket
R_Sock := C_Socket (SOSC.AF_INET, SOSC.SOCK_STREAM, 0);
if R_Sock = Failure then
goto Fail;
end if;
-- Connect listening socket
Res := C_Connect (R_Sock, Sin'Address, Len);
exit when Res /= Failure;
if Socket_Errno /= SOSC.EADDRINUSE then
goto Fail;
end if;
-- In rare cases, the above C_Bind chooses a port that is still
-- marked "in use", even though it has been closed (perhaps by some
-- other process that has already exited). This causes the above
-- C_Connect to fail with EADDRINUSE. In this case, we close the
-- ports, and loop back to try again. This mysterious Windows
-- behavior is documented. See, for example:
-- http://msdn2.microsoft.com/en-us/library/ms737625.aspx
-- In an experiment with 2000 calls, 21 required exactly one retry, 7
-- required two, and none required three or more. Note that no delay
-- is needed between retries; retrying C_Bind will typically produce
-- a different port.
pragma Assert (Res = Failure
and then
Socket_Errno = SOSC.EADDRINUSE);
Res := C_Close (W_Sock);
W_Sock := Failure;
Res := C_Close (R_Sock);
R_Sock := Failure;
end loop;
-- Since the call to connect(2) has succeeded and the backlog limit on
-- the listening socket is 1, we know that there is now exactly one
-- pending connection on L_Sock, which is the one from R_Sock.
W_Sock := C_Accept (L_Sock, Sin'Address, Len'Access);
if W_Sock = Failure then
goto Fail;
Set_Socket_Option
(Socket => Socket_Type (Fds (Write_End)),
Level => IP_Protocol_For_TCP_Level,
Option => (Name => No_Delay, Enabled => True));
end if;
-- Set TCP_NODELAY on W_Sock, since we always want to send the data out
-- immediately.
Set_Socket_Option
(Socket => Socket_Type (W_Sock),
Level => IP_Protocol_For_TCP_Level,
Option => (Name => No_Delay, Enabled => True));
-- Close listening socket (ignore exit status)
Res := C_Close (L_Sock);
Fds.all := (Read_End => R_Sock, Write_End => W_Sock);
return Thin_Common.Success;
<<Fail>>
declare
Saved_Errno : constant Integer := Socket_Errno;
begin
if W_Sock /= Failure then
Res := C_Close (W_Sock);
end if;
if R_Sock /= Failure then
Res := C_Close (R_Sock);
end if;
if L_Sock /= Failure then
Res := C_Close (L_Sock);
end if;
Set_Socket_Errno (Saved_Errno);
end;
return Failure;
return Res;
end Create;
----------