FreeTDS Development Group

["Rich Young" <rich AT experienceplus.com>]

I finally had a chance to run through these instructions on using gdb.
I have more than one script failing, so I'm pasting in backtrace info
for two examples. After running the backtrace, I followed the
instructions at http://bugs.php.net/bugs-generating-backtrace.php to
determine which function was responsible for the last execute() call.

#############################################
#Here are the results of the first backtrace:
#############################################

(gdb) r test.php
        <a bunch of HTML code comes out here, and then...>
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 182894185888 (LWP 21325)]
0x0000003f6fd71f07 in memcpy () from /lib64/tls/libc.so.6
(gdb) bt
#0  0x0000003f6fd71f07 in memcpy () from /lib64/tls/libc.so.6
#1  0x00000000004f8030 in _estrndup ()
#2  0x0000002a98a82b2b in zif_odbc_result () from
/usr/lib64/php4/odbc.so
#3  0x0000000000519ed8 in execute ()
#4  0x00000000005082ad in zend_execute_scripts ()
#5  0x00000000004dcc0a in php_execute_script ()
#6  0x000000000052198a in main ()
(gdb) frame 3
#3  0x0000000000519ed8 in execute ()
(gdb) print (char
*)(executor_globals.function_state_ptr->function)->common.function_name
Attempt to extract a component of a value that is not a structure.
(gdb)

############################################
#And here are the results of the second backtrace:
############################################

(gdb) r itin.php
        <a bunch of HTML code comes out here, and then...>
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 182894185888 (LWP 21364)]
0x0000003f6fd71f07 in memcpy () from /lib64/tls/libc.so.6
(gdb) bt
#0  0x0000003f6fd71f07 in memcpy () from /lib64/tls/libc.so.6
#1  0x00000000004f8030 in _estrndup ()
#2  0x0000002a98a82b2b in zif_odbc_result () from
/usr/lib64/php4/odbc.so
#3  0x0000000000519ed8 in execute ()
#4  0x00000000005082ad in zend_execute_scripts ()
#5  0x00000000004dcc0a in php_execute_script ()
#6  0x000000000052198a in main ()
(gdb) frame 3
#3  0x0000000000519ed8 in execute ()
(gdb) print (char
*)(executor_globals.function_state_ptr->function)->common.function_name
Attempt to extract a component of a value that is not a structure.
(gdb)

Apparently, it's the same problem affecting both scripts.
Unfortunately, I'm enough of a newbie here that I still don't understand
whether this is a PHP or FreeTDS bug.  Any insight?

--Rich Young, IT Dept.
ExperiencePlus! Specialty Tours, Inc.
rich AT ExperiencePlus.com
1-800-685-4565 
 

> -----Original Message-----
> From: freetds-bounces AT lists.ibiblio.org 
> [mailto:freetds-bounces AT lists.ibiblio.org] On Behalf Of 
> ZIGLIO, Frediano, VF-IT
> Sent: Thursday, January 04, 2007 3:45 AM
> To: FreeTDS Development Group
> Subject: Re: [freetds] MS-SQL ntext fields?
> 
> > 
> > Freddy & James-
> >     Thanks for the tip on specifying the TDS Version in tsql - it
> > was running version 4.2, and specifying 8.0 enabled the 
> > problem queries
> > to run fine.  isql runs the same queries without trouble (and always
> > has), but PHP is still crashing.  
> > 
> >     I'm beginning to think this is a PHP bug rather than a freeTDS
> > bug....  Do you agree?
> > 
> 
> Difficult to say. Perhaps our library is returning some invalid data
> that cause PHP to core so perhaps error occur in PHP but 
> problem is our
> driver...
> Which client charset are you using?
> 
> >     I'm reading up on how to get a gdb backtrace from the PHP crash,
> > but I suspect it might be more fruitful to browse PHP bug 
> discussions.
> > Chances are it's not a new bug, as I'm using CentOS and its 
> relatively
> > conservative package choices.
> > 
> 
> Get "php script.php" running (and coring too) now you can
> 
> $ gdb $(which php) core*
> 
> and at gdb prompt
> 
> $ bt
> 
> (to get back trace) or
> 
> $ gdb php
> 
> and at gdb prompt
> 
> $ r script.php
> 
> ... wait core ...
> 
> $ bt
> 
> >     BTW, I fed you a snippet from the wrong freetds.conf - I had
> > omitted the tds version =  line in a different one. After 
> making that
> > correction, the query runs fine in tsql without explicitly 
> setting the
> > TDS version.  (Sadly, adding the correct tds version 
> > instruction to the
> > conf file that actually matters didn't clear up my PHP crashing
> > trouble.)
> > 
> 
> freddy77
> 
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