[OPEN-ILS-DEV] PATCH: osrf_chat.c (memory leaks)

[Mike Rylander]

On Dec 29, 2007 12:26 PM, Scott McKellar <mck9 at swbell.net> wrote:
> This patch:

is also applied.

>
> 1. Makes sure that all members of OsrfChatServer and OsrfChatNode are
> explicitly initialized;
>
> 2. Plugs several actual or potential memory leaks.
>
> Commentary:
>
> 1. One way to leak memory is to overwrite a non-NULL pointer without
> freeing the thing that it pointed to.  However it can be difficult to
> determine, by inspecting the code, whether the pointer might have
> been non-NULL in the first place.
>
> In several cases, rather than try to analyze the entire flow of the
> program, I just threw in a test for NULL and freed the pointer if
> it wasn't NULL.
>
> It may be that these weren't leaks at all, in which case my additions
> will waste a few machine cycles.  At least we can be confident that
> we aren't leaking, regardless of how the rest of the program behaves.
>
> 2. When destroying an OsrfChatServer, we dutifully free mgr, which
> is a pointer to a socket manager.
>
> However a socket_manager owns a linked list of socket_nodes, each of
> which owns a socket.  I saw no sign that we were necessarily freeing
> all the socket_nodes or closing the sockets.
>
> Were I to analyze the program more carefully, I might determine that
> in practice we don't destroy the osrfChatServer until we have already
> cleared out the list of socket_nodes.
>
> But I was too lazy to do that.  So I replaced the free() with a call
> to socket_manager_free().  At worst I may be wasting a few machine
> cycles, but we can be more confident that we are leaking neither
> socket_nodes nor sockets.
>
> Scott McKellar
> http://home.swbell.net/mck9/ct/
>
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-- 
Mike Rylander
 | VP, Research and Design
 | Equinox Software, Inc. / The Evergreen Experts
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