[AWS] Possible leak found in aws-smtp-client.adb

[Thomas Løcke]

I'm calling AWS.SMTP.Client.Send to send an email:

    declare

       Server  : AWS.SMTP.Receiver;

    begin
       Server := AWS.SMTP.Client.Initialize
         (Server_Name => "localhost",
          Port        => 25);

       AWS.SMTP.Client.Send (Server => Server,
                                            From   => From,
                                            To     => Recipients,
                                            Subject => "Test",
                                            Message => "Top of the world!",
                                            Status => Status);

    exception
       when others =>
          Ada.Text_IO.Put_Line ("Trouble!");

    end;

And that works flawlessly, with no leaks at all, as long as there's a
functional SMTP server running at localhost.

But if I shutdown the SMTP server, the code starts to leak. On each
and every call to Send, 48 bytes are leaked, so calling it 1000 times
results in 48_000 leaked bytes. Nasty!

Here's the valgrind output:

    ==16987== 48 bytes in 1 blocks are definitely lost in loss record 139 of 212
    ==16987==    at 0x4C26F0E: malloc (in
/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
    ==16987==    by 0x7421D7: __gnat_malloc (in
/home/thomas/Ada/yolk/demo/exe/yolk_demo)
    ==16987==    by 0x57ECA7: aws__net__socket__2 (in
/home/thomas/Ada/yolk/demo/exe/yolk_demo)
    ==16987==    by 0x4E4183: aws__smtp__client__open (in
/home/thomas/Ada/yolk/demo/exe/yolk_demo)
    ==16987==    by 0x4E4865: aws__smtp__client__send__4 (in
/home/thomas/Ada/yolk/demo/exe/yolk_demo)
    ==16987==    by 0x47900F: yolk__email__composer__send (in
/home/thomas/Ada/yolk/demo/exe/yolk_demo)

>From a quick glance at the AWS code, it seems that everything is freed
properly, but since my Ada/AWS foo is still weak, I might've missed
something. I doubt that the leak originates in my own code, as what
I'm doing really is as simple as the example posted above. I
initialize an SMTP server, call Send and do some simple output if an
exception is raised. All done in a block, as shown.

The program has been compiled with GNAT GPL 2010 and the following parameters:

    for Default_Switches ("Ada")
      use ("-gnatwa",
             "-gnata",
             "-gnatVa",
             "-gnaty3abcdefhiklmnoprstux",
             "-Wall",
             "-O1",
             "-gnat05",
             "-g");

And valgrind is called like this:

    valgrind -v --leak-check=full --track-origins=yes yolk_demo

I'm at my wits end.

Sincerely,
Thomas Løcke

ps. I've tried this with the latest official AWS 2011 package and with
the latest dev commit d4538275d0dab54f8596f777d20bc999e6af6420. Same
result.