20000127: ldm; gempak; dchrly: segmentation violations

Tom,

Thanks for bringing this to my attention.
I tracked the core dumps of the dchrly decoder to an ill formed
metar report from KAFF where they reported GR in their remarks
without a size, eg:
KAFF 271955Z 36019G28KT 5SM VCSH FEW015 BKN025 BKN070 01/M01 A2997
     RMK PK WND 36028/43 SLP166 ESTMD SLP 8/510 9/520 PSR12 GR=

This group is supposed to be like GR 1/8

At any rate, you can add one line to the gempak source to fix as follows:

Edit $GEMPAKHOME/src/bridge/metar/dcdmtrmk.c and add around line 2535
add the line: if(*string == NULL) return FALSE;

This should look like:

 (++string);

      if(*string == NULL) return FALSE;

      if( (slash = strchr( *string, '/' )) != NULL ) {
         if( strcmp( *string, "M1/4" ) == 0 ) {
            Mptr->GR_Size = 1./8.;

Then build the routine and dchrly with:

cd $GEMPAKHOME/src/bridge/metar
make clean
make all
make clean

cd $GEMPAKHOME/src/programs/dc/dchrly
make clean
make all
make install
make clean

I will update the pl15 distribution with this fix as well.

Steve Chiswell
Unidata User SUpport

>From: Tom McDermott <address@hidden>
>Organization: .
>Keywords: 200001271546.IAA22032

>
>
>Today I'm receiving a bunch of messages about segmentation violations in
>my ldm log (no messages of this type for the last 3 weeks until today):
>
>Jan 27 12:54:25 vortex pqact[21322]: child 19581 terminated by signal 11
>Jan 27 13:09:26 vortex pqact[21322]: child 308 terminated by signal 11
>Jan 27 13:33:22 vortex pqact[21322]: child 4690 terminated by signal 11
>Jan 27 13:45:10 vortex pqact[21322]: child 10568 terminated by signal 11
>Jan 27 14:05:58 vortex pqact[21322]: child 13169 terminated by signal 11
>Jan 27 14:45:15 vortex pqact[21322]: child 15499 terminated by signal 11
>Jan 27 15:08:23 vortex pqact[21322]: child 21812 terminated by signal 11
>
>Evidently they're being caused by dchrly crashing:
>
>DCHRLY[308]: 000127/1254: Starting up.
>DCHRLY[4690]: 000127/1309: Starting up.
>DCHRLY[10568]: 000127/1333: Starting up.
>DCHRLY[13169]: 000127/1345: Starting up.
>DCHRLY[15499]: 000127/1405: Starting up.
>DCHRLY[21812]: 000127/1445: Starting up.
>DCHRLY[24220]: 000127/1508: Starting up.
>
>I rebuilt my entire gempak installation from the patch 15 distribution 10
>days ago but haven't experienced a problem until today.   I know this
>isn't much to go on but I thought I would ask and see if you had any
>ideas.  Thanks.
>
>Tom
>------------------------------------------------------------------------------
>Tom McDermott                          Email: address@hidden
>System Administrator                   Phone: (716) 395-5718
>Earth Sciences Dept.                   Fax: (716) 395-2416
>SUNY College at Brockport
>
>
>