ID: 32414
User updated by: d dot geels at grape dot ru
Reported By: d dot geels at grape dot ru
Status: Open
Bug Type: Session related
Operating System: any
PHP Version: 4.3.10, also 5
New Comment:
Tiny example, that always reproduces the bug.
<?
ini_set('session.use_cookies', 0);
session_id('1234');
session_cache_limiter('public');
session_start();
session_write_close();
?>
text
<?
function a(){
session_cache_limiter('none');
session_start();
session_write_close();
}
register_shutdown_function('a');
?>
If just call a() at the end -- no warnings, if a() called at shutdown
-- warning issued.
Previous Comments:
------------------------------------------------------------------------
[2005-03-22 18:43:53] d dot geels at grape dot ru
No, we don't use this at all, this option is always set to 0.
Just checked, ini option is set to 0, .htaccess doesn't change this
option.
------------------------------------------------------------------------
[2005-03-22 18:34:23] [EMAIL PROTECTED]
Do you have 'session.auto_start' set on somewhere?
(httpd.conf, .htaccess file, php.ini..)
------------------------------------------------------------------------
[2005-03-22 18:25:12] d dot geels at grape dot ru
There is one more detail, I forgot to mention:
I couldn't kill warning message by calling @start_session() in line 45.
Is this because of warning message issued somewhere in calls from
session_start()?
------------------------------------------------------------------------
[2005-03-22 18:16:04] d dot geels at grape dot ru
Just viewd latest session.c from CVS repository. There are not much
changes between versions 4 and 5, so bug still remains in PHP 5.
Somewhere here:
static int php_session_cache_limiter(TSRMLS_D)
{
php_session_cache_limiter_t *lim;
// for some reason, this string fails
if (PS(cache_limiter)[0] == '\0') return 0;
// I cant understand all this file, but I think, problem is
// that value 'none' is not properly recognized or processed
if (SG(headers_sent)) {
char *output_start_filename =
php_get_output_start_filename(TSRMLS_C);
int output_start_lineno = php_get_output_start_lineno(TSRMLS_C);
if (output_start_filename) {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot
send session
cache limiter - headers already sent (output started at %s:%d)",
output_start_filename, output_start_lineno);
} else {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot
send session
cache limiter - headers already sent");
}
return -2;
}
for (lim = php_session_cache_limiters; lim->name; lim++) {
if (!strcasecmp(lim->name, PS(cache_limiter))) {
lim->func(TSRMLS_C);
return 0;
}
}
return -1;
}
------------------------------------------------------------------------
[2005-03-22 17:38:57] d dot geels at grape dot ru
Description:
------------
The problem described already in user contributed noted in
documentation. Strange, that it is not yet fixed...
Also problem mentioned in http://bugs.php.net/bug.php?id=11213
==================================
laacz at laacz dot lv (28-Oct-2004 03:37)
If You are not using cookies to store session_id's, that does not mean,
that session_start() will not send any headers at all. It still sends
cache controlling information to user. For example:
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0,
pre-check=0
Pragma: no-cache
Even, if You set cache_limiter to none (via
ini_set('session.use_cookies', 0) or ini_set('session.cache_limiter',
'none')), session_start() still tries to send empty headers and that
causes error message "Cannot send session cache limiter - headers
already sent". So, use output buffering, if You need to output
something before session_start().
==================================
even session_cache_limiter('none') doesn't work
In my case, problem is that I call session_start(), then
session_write_close() in the beginning, then send data, then call
session_start(), then session_write_close() in the function, registered
on shutdown.
There are two reasons, why I do so:
1) there are several processes, that access same session (I use
md5($_SERVER['REMOTE_ADDR']) as session_id)
2) I can't buffer output at all. Amount of data is very large, it is a
file being downloaded. It must be sent ASAP.
Reproduce code:
---------------
if(!empty($_SERVER['HTTP_RANGE'])){
$sid = md5($_SERVER['REMOTE_ADDR']);
ini_set('session.use_cookies', 0);
session_cache_limiter('public'); // for IE "Open" bug
session_id($sid);
session_start(); //this one starts normally
//check, if this download thread is permitted or not
if(!empty($_SESSION['file_'.$file_id]) && $_SESSION['file_'.$file_id]
>= MAX_DOWNLOAD_THREADS){
header('HTTP/1.1 403 Forbidden', true, 403);
exit;
}elseif(!isset($_SESSION['file_'.$file_id]))
$_SESSION['file_'.$file_id] = 0;
$_SESSION['file_'.$file_id]++;
session_write_close();
//close session ASAP, because else other processes would be blocked
//this function will decrement threads counter...
function decrementCounter($sid, $file_id)
{
//this must help us evade "Warning: session_start(): Cannot send
session cache limiter - headers already sent"
session_cache_limiter('none');
session_id($sid);
session_start(); // this is line #45
//decrement threads counter
$_SESSION['file_'.$file_id]--;
session_write_close();
//close session ASAP
}
//... when script finished
register_shutdown_function('decrementCounter', $sid, $file_id);
}
Expected result:
----------------
No warnings in log file.
Actual result:
--------------
[Tue Mar 22 18:32:08 2005] [error] PHP Warning: session_start():
Cannot send session cache limiter - headers already sent (output
started at /home/httpd/pantech/htdocs/file.php:144) in
/home/httpd/pantech/htdocs/file.php on line 45
reproduced always, when user downloading a file
line 144 sends data to client:
echo fread( $fp, $size > READ_BLOCK_SIZE ? READ_BLOCK_SIZE : $size );
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--
Edit this bug report at http://bugs.php.net/?id=32414&edit=1
