Wireshark · Wireshark-dev: Re: [Wireshark-dev] Regenerating packet-parlay.c

[Luke Mewburn <luke@xxxxxxxxxxx>]

On 20-05-01 13:46, Jaap Keuter wrote:
  | On 5/1/20 12:02 PM, Luke Mewburn wrote:
  | > On 20-05-01 07:34, Jaap Keuter wrote:
  | >   | 
  | >   | > On 1 May 2020, at 04:13, Luke Mewburn <luke@xxxxxxxxxxx>
  | >   | > wrote: However, looking at the code some more, it appears
  | >   | > that generally wireshark_gen.py generates code in the order
  | >   | > the operations are defined; the exception (hah!) is the user
  | >   | > exceptions.
  | >   | > 
  | >   | > If I instead add at the top import collections and change
  | >   | > get_exceptionList() from ex_hash = {}  # holds a hash of
  | >   | > unique exceptions.  to ex_hash = collections.OrderedDict()
  | >   | > # holds a hash of unique exceptions.
  | >   | > 
  | >   | > This results in consistent generated code with both python
  | >   | > 2.7 (CentOS 7) and python 3.7 (Fedora 31).
  | >   | > 
  | >   | > I've also fixed a whitespace issue in the generated code by
  | >   | > indenting the break in
  | >   | > template_helper_switch_msgtype_default_end, so that it
  | >   | > matches the epan/dissectors code and other default
  | >   | > statements.
  | >   | > 
  | >   | > 
  | >   | > Here's a patch with my suggested fixes.  Or would you prefer
  | >   | > a commit/pull request (etc)?
  | >   | > 
  | >   | > 
  | >   | > regards, Luke.
  | >   | > 
  | >   | 
  | >   | Hi Luke,
  | >   | 
  | >   | That’s great, I didn’t have the opportunity yet to dig into
  | >   | this.  Nice that you compared Python 2.7 and 3.7 already.
  | >   | I’ll pick this up and put it in with the other fixes I've
  | >   | lined up, so you won’t have to push a change. I’ll credit you
  | >   | in the commit :)
  | >   | 
  | >   | Thanks, Jaap
  | 
  | He Luke,
  | 
  | Are you able to recreate the parlay dissector currently in the
  | repository with this. So far I haven't succeeded.
  | 
  | Thanks, Jaap

Yes, I regenerated the code using that patch to tools/wireshark_gen.py,
and it builds fine across a couple of platforms.

(BTW: I needed a separate build fix on CentOS 7 for packet-dof.c
and I've pushed a change to review for that)


I wrote a simple wrapper tool idl-regen (attached) to assist each
regen from the idl, used with something like:
	$ ./idl-regen ../epan/dissectors/
	mmccs.idl:120: Warning: Identifier 'EventType' clashes with CORBA 3 keyword 'eventtype'
	policy_data.idl:119: Warning: Anonymous sequences for recursive unions are deprecated. Use a forward declaration instead.
	policy_data.idl:123: Warning: Anonymous sequences for recursive unions are deprecated. Use a forward declaration instead.

I get the same .c files generated from either:
- CentOS 7,  python 2.7.5, omniidl 4.2.0
- Fedora 31, python 3.7.6, omniidl 4.2.3


Three files get changes from git master:
- packet-gias.c
- packet-parlay.c
- packet-tango.c

The generated code for packet-gias.c and packet-tango.c
differ to git master because of the following fix to idl2wrs
that doesn't appear to have been rerun to regenerate those files:
	commit 443df93896
	Author: Yannik Enss <Yannik.Enss@xxxxxxxxxxxxxxxxx>
	Date:   2019-05-29 14:20:42 +0200

	idl2wrs: fix 'undeclared identifier' error

	the 'x_octetx' variables were removed a few years back, replace them with get_CDR_xxx()
	I8cf3410d8a152c834e7019f7d1d80de3798530c3


packet-parlay.c gets that above change as well as many other
changes to generated code for /* User exception filters */,
mostly in the ordering of the declarations and the list of
array entries added to proto_register_giop_parlay() variable
	static hf_register_info hf[] 


As far as I can tell, the new packet-parlay.c has the same
number of lines, just in different order.
I manually applied a change of:
	disc_s_XXX = (gint32) u_octet4;     /* save Enum Value discriminant and cast to gint32 */
to
	disc_s_XXX = (gint32) get_CDR_ulong(tvb,offset,stream_is_big_endian, boundary);     /* save Enum Value  discriminant and cast to gint32 */
and compared the regenerated file with that, they both still have same
size and number of lines, and if I sort the lines in both the files are
identical. (Of course, that doesn't compile... :)


I tried doing some comparison of the generated object files but they
differed too much, probably because of the reordering of the source
lines, even though the hf[] array ends up with the same content in
different order.


I don't know how much more verification is required, however.
It looks like in the past there have been changes to wireshark_gen.py
and then regen of packet-parlay.c that reordered a lot of the content.
For example, see commit c99bee9b5d on 2019-06-05.




regards,
Luke.

#!/bin/sh

set -e
prog=$(basename $0)

if [ $# -lt 1 ]; then
	echo 1>&2 "usage: ${prog} outdir"
	exit 1
fi
outdir="$1"

if [ ! -d "${outdir}" ]; then
	echo 1>&2 "${prog}: no such directory '$outdir'"
	exit 1
fi

omniidl -p ../tools -b wireshark_be coseventcomm.idl > "${outdir}"/packet-coseventcomm.c
omniidl -p ../tools -b wireshark_be cosnaming.idl > "${outdir}"/packet-cosnaming.c
omniidl -p ../tools -b wireshark_be tango.idl > "${outdir}"/packet-tango.c

(cd gias && omniidl -p ../../tools -b wireshark_be gias.idl ) > "${outdir}"/packet-gias.c

(cd parlay && omniidl -p ../../tools -b wireshark_be Parlay.idl ) > "${outdir}"/packet-parlay.c

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