Peter Johansson wrote:
2008/3/13, Luis EG Ontanon <luis@xxxxxxxxxxx <mailto:luis@xxxxxxxxxxx>>:
On Thu, Mar 13, 2008 at 2:38 PM, Stig Bjørlykke <stig@xxxxxxxxxxxxx
<mailto:stig@xxxxxxxxxxxxx>> wrote:
> I suppose we have to leave them allocated if we don't know how
libsmi
> is compiled?
> I have almost no experience on Windows, do we compile this our self?
I compiled it, I just made changes to the makefile (and build only the
dll), I have no clue whether HAVE_VASPRINTF was defined or not.
Did you compile it using MSVC 6? Could this then be of the same type of
issue that is with adns, hence it is required to recompile libsmi too if
using another compiler for Wireshark on Windows than MSVC 6. Developer
Studio 2005EE for instance?
My 2 cents ....
1. As noted previously: the problem is that there are (in effect)
malloc(...) statements in libsmi which allocate storage and free(...)
statements in oids.c to free that storage.
This is a non-starter on Windows if libsmi.dll is linked
against a different msvcrt than wireshark. (Think allocating
memory in one heap and trying to free it in a completely
different heap). This is the case if Wireshark is built,
for example, using vc 2005EE(using msvcr80.dll) since
our version of the Windows libsmi is currently built
with vc6 (using msvcrt.dll).
(If this 'gotcha' isn't mentioned someplace in the developer docs, it
probably should be. If needed, I'll add something about the
whole issue of using mixed run-time MSVCRT libraries
with Wireshark on Windows).
2. Possible solutions:
a. (As a temporary workaround for anyone wishing to able to
build a working Wireshark with other than vc6 which uses
the current libsmi: Remove the free(...) statements in oids.c).
b. Compile libsmi as part of the build process (like adns & etc).
(It would be really nice not to have to do this ....).
c. Looking at the smi code: there's a smiFree function in
the smi file utils.c which seems like it might be
just what is needed.
However there's something to do with an
#ifdef HAVE_DMALLOC_H which I don't altogether understand. Maybe
this can be ignored since I'm pretty sure that our vanilla
Windows build done using the makefile mentioned previously
does not define this symbol.
If so, a solution might be (on Windows only):
1. exporting smiFree from libsmi (and then rebuilding
the library);
2. adding an extern smiFree(void *ptr) to oid.c;
3. changing the various free(...) statements in oids.c to
smiFree(...).
(Obviously it would be much cleaner if smiFree were available
as part of the API so that it could be used on any
platform. Or: maybe there's another better way .....
Possibly we could ask upstream if something can be done).
Also: I don't think it makes any difference whether
HAVE_VASNPRINTF & etc were defined when the Windows libsmi
was built.
Whether a library version of vasnprintf or the libsmi
version is used, storage is allocated and would need to be freed.
Thoughts ??
Bill
