1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--         G N A T . E X P E C T . N O N _ B L O C K I N G _ S P A W N      --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--                    Copyright (C) 2005-2010, AdaCore                      --
10--                                                                          --
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 3,  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.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This package provides a target dependent non-blocking spawn function
33--  for use by the VMS GNAT.Expect package (g-expect-vms.adb). This package
34--  should not be directly with'ed by an application program.
35
36--  This version is for Alpha/VMS
37
38separate (GNAT.Expect)
39procedure Non_Blocking_Spawn
40  (Descriptor  : out Process_Descriptor'Class;
41   Command     : String;
42   Args        : GNAT.OS_Lib.Argument_List;
43   Buffer_Size : Natural := 4096;
44   Err_To_Out  : Boolean := False)
45is
46   function Alloc_Vfork_Blocks return Integer;
47   pragma Import (C, Alloc_Vfork_Blocks, "decc$$alloc_vfork_blocks");
48
49   function Get_Vfork_Jmpbuf return System.Address;
50   pragma Import (C, Get_Vfork_Jmpbuf, "decc$$get_vfork_jmpbuf");
51
52   function Get_Current_Invo_Context
53     (Addr : System.Address) return Process_Id;
54   pragma Import (C, Get_Current_Invo_Context,
55     "LIB$GET_CURRENT_INVO_CONTEXT");
56
57   Pipe1, Pipe2, Pipe3 : aliased Pipe_Type;
58
59   Arg      : String_Access;
60   Arg_List : aliased array (1 .. Args'Length + 2) of System.Address;
61
62   Command_With_Path : String_Access;
63
64begin
65   --  Create the rest of the pipes
66
67   Set_Up_Communications
68     (Descriptor, Err_To_Out, Pipe1'Access, Pipe2'Access, Pipe3'Access);
69
70   Command_With_Path := Locate_Exec_On_Path (Command);
71
72   if Command_With_Path = null then
73      raise Invalid_Process;
74   end if;
75
76   --  Fork a new process (it is not possible to do this in a subprogram)
77
78   Descriptor.Pid :=
79     (if Alloc_Vfork_Blocks >= 0
80      then Get_Current_Invo_Context (Get_Vfork_Jmpbuf) else -1);
81
82   --  Are we now in the child
83
84   if Descriptor.Pid = Null_Pid then
85
86      --  Prepare an array of arguments to pass to C
87
88      Arg   := new String (1 .. Command_With_Path'Length + 1);
89      Arg (1 .. Command_With_Path'Length) := Command_With_Path.all;
90      Arg (Arg'Last)        := ASCII.NUL;
91      Arg_List (1)          := Arg.all'Address;
92
93      for J in Args'Range loop
94         Arg                     := new String (1 .. Args (J)'Length + 1);
95         Arg (1 .. Args (J)'Length)  := Args (J).all;
96         Arg (Arg'Last)              := ASCII.NUL;
97         Arg_List (J + 2 - Args'First) := Arg.all'Address;
98      end loop;
99
100      Arg_List (Arg_List'Last) := System.Null_Address;
101
102      --  This does not return on Unix systems
103
104      Set_Up_Child_Communications
105        (Descriptor, Pipe1, Pipe2, Pipe3, Command_With_Path.all,
106         Arg_List'Address);
107   end if;
108
109   Free (Command_With_Path);
110
111   --  Did we have an error when spawning the child ?
112
113   if Descriptor.Pid < Null_Pid then
114      raise Invalid_Process;
115   else
116      --  We are now in the parent process
117
118      Set_Up_Parent_Communications (Descriptor, Pipe1, Pipe2, Pipe3);
119   end if;
120
121   --  Create the buffer
122
123   Descriptor.Buffer_Size := Buffer_Size;
124
125   if Buffer_Size /= 0 then
126      Descriptor.Buffer := new String (1 .. Positive (Buffer_Size));
127   end if;
128end Non_Blocking_Spawn;
129