Wordpress admin stopped working after upgrade to 3.5.1 - php

Question

Today I tried to update Wordpress to the latest version (3.5.1). After doing this, I can't open wp-admin/index.php anymore. It gives me a 404 error. I've looked into the index.php file and it breaks when the function auth_redirect() is called. Here's the code of that function:
function auth_redirect() {
// Checks if a user is logged in, if not redirects them to the login page
$secure = ( is_ssl() || force_ssl_admin() );
$secure = apply_filters('secure_auth_redirect', $secure);
// If https is required and request is http, redirect
if ( $secure && !is_ssl() && false !== strpos($_SERVER['REQUEST_URI'], 'wp-admin') ) {
if ( 0 === strpos( $_SERVER['REQUEST_URI'], 'http' ) ) {
wp_redirect( set_url_scheme( $_SERVER['REQUEST_URI'], 'https' ) );
exit();
} else {
wp_redirect( 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );
exit();
}
}
if ( is_user_admin() )
$scheme = 'logged_in';
else
$scheme = apply_filters( 'auth_redirect_scheme', '' );
if ( $user_id = wp_validate_auth_cookie( '', $scheme) ) {
do_action('auth_redirect', $user_id);
// If the user wants ssl but the session is not ssl, redirect.
if ( !$secure && get_user_option('use_ssl', $user_id) && false !== strpos($_SERVER['REQUEST_URI'], 'wp-admin') ) {
if ( 0 === strpos( $_SERVER['REQUEST_URI'], 'http' ) ) {
wp_redirect( set_url_scheme( $_SERVER['REQUEST_URI'], 'https' ) );
exit();
} else {
wp_redirect( 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );
exit();
}
}
return; // The cookie is good so we're done
}
// The cookie is no good so force login
nocache_headers();
$redirect = ( strpos( $_SERVER['REQUEST_URI'], '/options.php' ) && wp_get_referer() ) ? wp_get_referer() : set_url_scheme( 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );
$login_url = wp_login_url($redirect, true);
wp_redirect($login_url);
exit();
}
However I can't find the specific part where it breaks, since it's not giving me an error message, it just shows a 404 page, and in Firefox it says it's not redirecting correctly.
Could someone please help me out on this?
Thank you!
Some additional information:
I've found the line where it breaks, it is:
wp_redirect( 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );
Echoing $_SERVER['HTTP_HOST'] and $_SERVER['REQUEST_URI'] gives me the expected result (www.domain.com/blog). However it just doesn't work :(

Answer 1

I have had similar issues in the past. But it usually involves a new plugin installation... Couple of things:
Try to increase the RAM available. WP has given me hassles in the past similar to this and it was RAM related. You should be able to increase the RAM in your .htaccess file
Is this a production system? If not, perhaps make a note of all the plugins, delete them, try access the system. If that works, then you know the issue was plugin based and not WP itself. You can then systematically add the plugins back one by one and determine which one caused the issue.