Edit report at https://bugs.php.net/bug.php?id=46473&edit=1
ID: 46473
Comment by: brandonkirsch at gmail dot com
Reported by: philippe dot marasse at ac-poitiers dot fr
Summary: php segfaults on some queries using pdo_odbc &
ibm-db2 on a 64bits platform
Status: Assigned
Type: Bug
Package: PDO related
Operating System: Linux Red Hat EL5 x86_64
PHP Version: 5.2.6
Assigned To: iodbc
Block user comment: N
Private report: N
New Comment:
I am very familiar with this problem - IT IS NOT A BUG IN PHP.
64-bit IBM iSeriesAccess ODBC drivers are built against an antiquated
definition of what 64-bit ODBC should be. Instead, the IBM drivers use 32-bit
values in places where 64-bits should be used.
The end result is that a 32-bit value ("-1" to represent NULL) is interpreted
by 64-bit PHP as a large number, causing it to read an invalid memory address
and therefore segfault.
You can ask IBM for a better ODBC driver, but they ignored us when we tried.
I have a custom patch for php_odbc.c that "fixes" the problem by hacking up PHP
ODBC bindings to treat all ODBC SQL_NULL_DATA values as 32-bit. There are small
potential downsides that can occur if you use this patch with a real 64-bit
ODBC driver AND you try to access fields > 4GB.
http://www.perceptionilluminates.com/php/php_odbc.c -- It's antiquated (PHP
5.2.17) but it is also well commented, so you can port the hack to a modern
version if you'd like.
Previous Comments:
------------------------------------------------------------------------
[2009-06-30 19:23:57] d dot stcyr at streamfoundry dot com
Was able to circumvent by configuring (now, PHP 5.2.10) with --enable-debug.
PHP 5.2.10 without --enable-debug fails the same way as did 5.2.9. Can someone
advise if this is the same problem and a prognosis for correction?
------------------------------------------------------------------------
[2009-06-24 15:57:26] d dot stcyr at streamfoundry dot com
I believe we have a same/similar situation running PHP 5.2.9 on 64-bit SLES10 -
with the ibm-db2 1.8.2 pdo_odbc extension. Getting a "Child pid nnn exit signal
Segmentation fault (11)". Here is a simple recreate script trying to connect to
the DB2 "SAMPLE" database:
<?php
$dbconn = new PDO('odbc:SAMPLE','db2inst1','pw'); /* pw not actual pw */
?>
Program terminated with signal 11, Segmentation fault.
#0 _zval_ptr_dtor (zval_ptr=0x3fffff31c70)
at /opt/SFI/php-5.2.9/Zend/zend_execute_API.c:412
412 (*zval_ptr)->refcount--;
Backtrace:
#0 _zval_ptr_dtor (zval_ptr=0x3fffff31c70)
at /opt/SFI/php-5.2.9/Zend/zend_execute_API.c:412
#1 0x0000020000a36282 in zend_do_fcall_common_helper_SPEC (
execute_data=0x3fffff31ec0) at /opt/SFI/php-5.2.9/Zend/zend_execute.h:155
#2 0x0000020000a26992 in execute (op_array=0x20002bb0d90)
at /opt/SFI/php-5.2.9/Zend/zend_vm_execute.h:92
#3 0x0000020000a032ac in zend_execute_scripts (type=<value optimized out>,
retval=0x0, file_count=2) at /opt/SFI/php-5.2.9/Zend/zend.c:1134
#4 0x00000200009ba4c4 in php_execute_script (primary_file=0x3fffff344d0)
at /opt/SFI/php-5.2.9/main/main.c:2023
#5 0x0000020000a970c8 in php_handler (r=0x2aaaade5ba8)
at /opt/SFI/php-5.2.9/sapi/apache2handler/sapi_apache2.c:632
#6 0x000002aaaaaedce0 in ap_run_handler () from /usr/sbin/httpd2-prefork
#7 0x000002aaaaaf1516 in ap_invoke_handler () from /usr/sbin/httpd2-prefork
#8 0x000002aaaaafccd8 in ap_process_request () from /usr/sbin/httpd2-prefork
#9 0x000002aaaaafa08c in ?? () from /usr/sbin/httpd2-prefork
#10 0x000002aaaaaf55b4 in ap_run_process_connection ()
from /usr/sbin/httpd2-prefork
#11 0x000002aaaab01190 in ?? () from /usr/sbin/httpd2-prefork
#12 0x000002aaaab014b0 in ?? () from /usr/sbin/httpd2-prefork
#13 0x000002aaaab0158a in ?? () from /usr/sbin/httpd2-prefork
#14 0x000002aaaab021d4 in ap_mpm_run () from /usr/sbin/httpd2-prefork
#15 0x000002aaaaad8646 in main () from /usr/sbin/httpd2-prefork
Please let me know if this falls within the known exposure of the work being
done on this bug. And a status?
Thanks.
------------------------------------------------------------------------
[2009-04-25 15:15:16] [email protected]
iodbc: What is the status with this fix? (if this still isn't fixed,
please update the PHP version..)
------------------------------------------------------------------------
[2008-11-07 11:45:59] [email protected]
I am working on a fix for pdo_odbc to bring it up to ODBC 3.51 API
specification including full 64bit support, similar to the work i did on
the regular ext/odbc code.
------------------------------------------------------------------------
[2008-11-03 15:35:13] philippe dot marasse at ac-poitiers dot fr
Description:
------------
On our both platforms (32 & 64 bits), we have php compiled with support for IBM
DB2 database via pdo_odbc extension. We ran into unexpected segfaults deploying
a new application on a 64 bits server.
We have tested several client version of DB2 but nothing helped.
At last, it seemed that pdo_odbc extensions did not compile properly, as we got
several warnings like :
passing argument 2 of 'SQLRowCount' from incompatible pointer type
Bug #32830 (related to odbc, not pdo_odbc) points out the same issue.
We wrote a little patch that works for us (tm), available at :
http://huan.ac-poitiers.fr/pdo_odbc_db2-x86_64.patch
Rgds.
Reproduce code:
---------------
<?php
$toto = new PDO("odbc:mydb","user","password");
$req = "SELECT ETA_DENOMINATION FROM ETABLISSEMENT WHERE ETA_DEPARTEMENT = 16
AND ETA_RNE = '0160001P'";
$machin = $toto->query($req);
$truc = $machin->fetchObject();
?>
Expected result:
----------------
nothing indeed :-), it's just a script we used to isolate a query which crashes
only on our 64bits servers (of course, it works fine on 32bits platform).
Actual result:
--------------
segfault... unless the value of ETA_DENOMINATION is not NULL.
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=46473&edit=1
