php / php/php-src

Resource ID space overflow: Better approach to incremental resource id assignment

Ouverte
#19,253 3 commentaires 0 réactions 0 personnes assignées Voir sur GitHub

Personne n'a encore pris cette issue.

Bug Status: Needs Triage
Langage dominant
C
Étoiles
40.4k
Forks
8.1k
Merge moyen
2 j 13 h
PR mergées (30 j)
96

Description

Description

We have the following simple code that runs in a daemon which is expected to to run very long time. However it looks like a new resource id is assigned every time this runs. And this runs a lot as we write to a ramdisk.
The following code:

61
62 file_put_contents("/dev/shm/somefile.txt", $data, LOCK_EX);
63 

Resulted in this output:

PHP Fatal error:  Resource ID space overflow in cache.class.php on line 62

But I expected this output instead:

No errors.
I understand that file_put_contents() creates a temporary file resource on each run and probably it's reaching  PHP_INT_MAX to cause this fatal error.
There is only one function get_resource_id() to guess and deal with this issue. Workaround is to keep file handles active during execution.

A)
PHP can handle this by resetting it back to 0 and adding a check to compare it to existing active resources(to avoid conflict) If this is not feasible, I could propose following:
1) In addition to get_resource_id(), we need **get_all_resource_ids**() : Return all active variables with resource ids
2) **resource_id_update**(existing, new) to move active variables to a specific range,
3) **resource_id_range** (0, PHP_INT_MAX) : This would reset back to start when max is reached.

With these extra methods, long running processes can allocate their active resources to a range and let dynamic resource id allocation out of conflict.

B) Another simpler approach could be: Assuming program creates all permanent resources for that run session after a few seconds, program can call a new method: resource_set_dynamic(). This method should record current+1 resource id in memory as "start point" and whenever overflow is due, it can reset it back to start point. This would avoid conflict with permanent resources which would be already created.

C) Checking against existing IDs could be another approach but this may have some impact on performance.
PHP Version
PHP 8.2.7 (cli) (built: Jul 20 2023 18:02:54) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.2.7, Copyright (c) Zend Technologies
    with Zend OPcache v8.2.7, Copyright (c), by Zend Technologies
Operating System

Debian 12.11

Guide de contribution

Ouvrir le guide de contribution

Par où commencer

  1. Lisez l'issue en entier, puis le guide de contribution du projet.
  2. Signalez en commentaire que vous la prenez — cela évite que deux personnes fassent le même travail.
  3. Forkez le dépôt et travaillez sur une branche.
  4. Ouvrez une pull request qui référence le numéro de l'issue.

Piste de recherche

Reproduisez le cas du daemon de longue durée de cache.class.php à la ligne 62 à l’aide de file_put_contents() sur /dev/shm avec PHP 8.2.7 CLI, puis tracez l’allocation de resource-ID atteinte par ce point d’entrée. L’issue présente plusieurs stratégies d’allocation concurrentes, mais ne définit pas quel comportement ou quel test devrait établir l’achèvement.

Rédigé par le modèle d'indexation à partir du texte de l'issue.

Évaluation

Stack technique
php
Domaine
backend
Type d'issue
Bug
Difficulté
5/5
Temps estimé
Plus d'une semaine
Activité
À l'abandon
Clarté
À clarifier
Accessibilité débutants
25/100

Recevez les nouvelles issues par e-mail

Un résumé court des issues GitHub adaptées aux débutants.