Re: Bug#153948: Need help with afio on powerpc

[Koen Holtman <koen@hep.caltech.edu>]

Hi all, 

I had to make a big diagram of the thread in order to understand
everything.  Now I want to summarise where we are, as far as I can
determine, and then add some new points.

0) linux 64 bit file support is still a bit of a mess, see the afio
history file.

1) in Debian afio 2.4.7-3. Dirk E set options -D_FILE_OFFSET_BITS=64
D_LARGEFILE_SOURCE + in order write archives larger than 2gb.  If this
is used, then off_t gets to be 64 bits, (maybe inode_t also?), which
seems (so far) harmless on intel, but on powerpc triggers bugs due to
casts.

2) Dieter S reported such a cast related bug, this was fixed by
   changing some sprintf statements to cast the argument asb->sb_size
   to (long int) asb->sb_size.  This is debian bug 144986

3) Stephen van Egmond also had problems with afio 2.4.7-3,
   investigations led to the identification of one other casting
   related bug, in that a call to inalloc() did not apply the right
   conversion, this can be fixed by changing:
    
    afio.h: void inalloc(off_t)
    afio.c: STATIC void inalloc(off_t len)

4) Stephan also made some other changes to eliminate warnings
   and add full declarations on the .h file etc. this led to 
   Dirk producing a version 2.4.7-6 on 

     http://dirk.eddelbuettel.com/edd/code/debian/UnderReview/

5) Dieter S still reports (on 30 Jul) that this above 2.4.7-6 has `the
   same error' which is an error in executing the -t option.  This is
   worrying, and maybe Dieter wants to produce a test case for Stephen
   to try to reproduce on his powerpc installation.

numbers 3-5 are captured in the logs of debian bug 153948

Now for some additions of my own:

6) I agree completely with Stephen's conclusions that there may be
   more endianness bugs lurking, so in the short term, I recommend to
   Dirk that any afio release on debian that pretends to be stable
   should omit the -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE options
   in the powerpc builds so as to avoid any endianness bugs.

7) Stephen recommends modernising the code base, I agree with this,
   and notice that already some modernisation was done in the massive
   patch file that produces 2.4.7-6.

8) HOWEVER some parts of this patch I do not want to fold into the
   main afio tree, in particular I do not want to have any assumption
   that printf/scanf can deal with 64 bit ints at all, because (from
   experience!) I know that this would cause lots of pain on some
   non-gcc non-linux platforms.  So I will (have to) do my own
   modernisation, warning, etc pass based on the patch file.

9) Depending on the weather. i.e. if we get a few rainy days, (and I
   am not in California but in Holland right now), I might soon
   release a modernised afio source base to Dirk, so that we can avoid
   a futher branching between my afio code base and Dirk's afio/debian
   revisions.  No hard promises or deadlines though.

Please tell me if I missed anything important.  Are the patches in
point 4 still the latest ones?

In terms of me getting access to a powerpc machine: I don't want to
have it right now, but if I get going on this (and depending on the
weather) I might want to later.

Cheers,

Koen.