[geos-devel] Segmentation Fault in ARM platform

[Paul Ramsey]

I guess if some part of the code is trying to interpret a mis-aligned
32-bit word, things could get interesting.

http://en.wikipedia.org/wiki/Endianness#Middle-endian

On Sat, Feb 28, 2009 at 3:05 PM, Paul Ramsey <pramsey at opengeo.org> wrote:
> Fun. I guess porting our software to the iPhone is going to take some work :)
>
> P
>
> On Sat, Feb 28, 2009 at 2:39 PM, Frank Warmerdam <warmerdam at pobox.com> wrote:
>> Paul Ramsey wrote:
>>>
>>> You're going to want to find someone who can re-produce this, which
>>> means someone with a big-endian platform. Perhaps Frank can on his old
>>> iBook. Note that you are transferring WKB from OGR to GEOS, so the
>>> problem could be the writing step in OGR (writing something invalid)
>>> or the reading step in GEOS (screwing up). Attach your program to an
>>> issue in trac.
>>
>> Paul,
>>
>> As I understand it the ARM is being used in "middle endian"
>> mode, or at least is not a traditional big endian system so I
>> don't believe my iBook will produce the same problem.
>>
>> I'm personally not too keen on making all my software support this
>> ... distinct ... endian case.  I'm fairly confident that Adriano is
>> only seeing the tip of the iceberg so far.
>>
>> Best regards,
>>
>>> On Sat, Feb 28, 2009 at 12:45 PM, Adriano C Naspolini
>>> <adriano at arvus.com.br> wrote:
>>>>
>>>> Hi people,
>>>> I recently installed gdal-1.6.0+geos-3.0.3 in my pc as in my target
>>>> prataform (an ARM). Initially, i had an endianess problem with gdal (the
>>>> target arm is little endian in bytes but big endian in words, so 0x1234
>>>> becomes 0x3412 and 0x12345678 becomes 0x56781234). After patching
>>>> shapelib
>>>> it's working.
>>>> The problem now is with geos: a segmentation fault when I use Contains()
>>>> function (also with Crosses(), there are certainly others). I think this
>>>> could be the same endianness problem, or something like it, because the
>>>> program runs normally on my pc.
>>>>
>>>> Backtrace from GDB:
>>>> #0  0x2c327dfc in memcpy () from /lib/libc.so.6
>>>> #1  0x2c204d7c in std::basic_streambuf<char, std::char_traits<char>
>>>>>
>>>>> ::xsgetn () from /usr/lib/libstdc++.so.5
>>>>
>>>> #2  0x2c43e580 in std::istream::read () from /usr/lib/libstdc++.so.6
>>>> #3  0x2abb58a4 in geos::io::WKBReader::readGeometry (this=0x7f5ff8a0) at
>>>> ../../source/headers/geos/io/ByteOrderDataInStream.inl:58
>>>> #4  0x2aad8ed8 in GEOSGeomFromWKB_buf (wkb=0x247f28 "\001\003", size=93)
>>>> at
>>>> geos_c.cpp:598
>>>> #5  0x2b148d4c in OGRGeometry::exportToGEOS (this=0x263fa0) at
>>>> ogrgeometry.cpp:1706
>>>> #6  0x2b148614 in OGRGeometry::Contains (this=0x7f5ff8b0,
>>>> poOtherGeom=0x0)
>>>> at ogrgeometry.cpp:2560
>>>> #7  0x0001ee8c in Mapa::getAttr (this=0xac818,
>>>> longitude=-47.590694333333332, latitude=-15.337605333333332) at
>>>> src/model/mapa.cpp:191
>>>>
>>>> Any Idea?
>>>>
>>>> Thank you.
>>>>
>>>> Adriano
>>>>
>>>>
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>>>>
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>>>
>>
>>
>> --
>> ---------------------------------------+--------------------------------------
>> I set the clouds in motion - turn up   | Frank Warmerdam,
>> warmerdam at pobox.com
>> light and sound - activate the windows | http://pobox.com/~warmerdam
>> and watch the world go round - Rush    | Geospatial Programmer for Rent
>>
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>