Hi !

I have the following problem:

I'm using php4 session management with user defined functions to read/write
session data from/to a mysql database. Sometimes session variables are not
written correctly to the database, although they are read correctly and not
changed on the page. I have logged the values the read function returns as
well as the values passed to the write function:

This is the correct output:

(w) 6ab3322c74ba731179b210dc4401a928:
(r) 6ab3322c74ba731179b210dc4401a928:
(w) 6ab3322c74ba731179b210dc4401a928: auth_name|s:4:"test";auth_flags|s:1:"1";
(r) 6ab3322c74ba731179b210dc4401a928: auth_name|s:4:"test";auth_flags|s:1:"1";
(w) 6ab3322c74ba731179b210dc4401a928: auth_name|s:4:"test";auth_flags|s:1:"1";
(r) 6ab3322c74ba731179b210dc4401a928: auth_name|s:4:"test";auth_flags|s:1:"1";
(w) 6ab3322c74ba731179b210dc4401a928: auth_name|s:4:"test";auth_flags|s:1:"1";
(r) 6ab3322c74ba731179b210dc4401a928: auth_name|s:4:"test";auth_flags|s:1:"1";
(w) 6ab3322c74ba731179b210dc4401a928: auth_name|s:4:"test";auth_flags|s:1:"1";

This is the wrong output:

(w) 3e8eab99d3e33bfe8393a0c4d0b8e987:
(r) 3e8eab99d3e33bfe8393a0c4d0b8e987:
(w) 3e8eab99d3e33bfe8393a0c4d0b8e987: auth_name|s:4:"test";auth_flags|s:1:"1";
(r) 3e8eab99d3e33bfe8393a0c4d0b8e987: auth_name|s:4:"test";auth_flags|s:1:"1";
(w) 3e8eab99d3e33bfe8393a0c4d0b8e987: auth_name|s:4:"test";auth_flags|s:1:"1";
(r) 3e8eab99d3e33bfe8393a0c4d0b8e987: auth_name|s:4:"test";auth_flags|s:1:"1";
(w) 3e8eab99d3e33bfe8393a0c4d0b8e987: auth_name|N;!:"test";auth_flags|
(r) 3e8eab99d3e33bfe8393a0c4d0b8e987: auth_name|N;!:"test";auth_flags|
(w) 3e8eab99d3e33bfe8393a0c4d0b8e987: auth_name|N;!:"test";auth_flags|

The above example is the output of a simple frameset with 3 frames.
Sometimes I get the correct output and sometimes I get the wrong one
on exactly the same set of pages. Both variables are never changed.

There should be no programming errors in my read/write functions...
In the read function I simply read from db, output the result into
a logfile and return the result. The example above shows reading works
perfectly. And the write function outputs the passed value into the
logfile before writing it to the database and as the above example
shows the passed value is not correct.

Configuration:

Linux: Linux 2.2.16 (Suse Distribution)
Apache: Apache/1.3.19 (Unix) PHP/4.0.4pl1 mod_ssl/2.8.1 OpenSSL/0.9.6
MYSQL: 3.22.32
PHP: PHP4.04pl1 with Zend Optimizer

Relevant settings from php.ini:

variables_order         =       "EGPCS"
register_globals        =       On
register_argc_argv      =       On
post_max_size           =       8M
gpc_order               =       "GPC"

; Magic quotes
magic_quotes_gpc        =   On
magic_quotes_runtime		=   Off
magic_quotes_sybase     =   Off

session.save_handler      = user
session.save_path         = /tmp
session.use_cookies       = 1
session.name              = PHPSESSID
session.auto_start        = 0
session.cookie_lifetime   = 0
session.cookie_path       = /
session.cookie_domain     =                                                        
session.serialize_handler = php
session.gc_probability    = 1
session.gc_maxlifetime    = 1440
session.referer_check     =
session.entropy_length    = 0
session.entropy_file      =
; session.entropy_length    = 16
; session.entropy_file      = /dev/urandom
session.cache_limiter     = nocache
session.cache_expire      = 180
session.use_trans_sid     = 1
url_rewriter.tags         = "a=href,area=href,frame=src,input=src,form=fakeentry"

any .htacces files I used only change include path or auto prepend file.