Writing PHP opcode and have it executed. How to do?

Question

How can I write PHP opcode, save it in a file and make the Zend Engine execute it? Any method or hack is welcome, as long as it does the trick.

Borneol

<smile> at "no well-intentioned answers that are not precisely addressing [the] question". Are miserable or angry answers that don't address the question acceptable? – Prefect

@Prefect ... look at Mo.sch's answer ... PHP-questions always attract such answers ... and did you -1 one me? oh man ... – Borneol

No, no -1 from me; I always try to state why I downvote :) – Prefect

Why downvote? It's a perfectly valid (and interesting) question. – Gonzalez

@Gonzalez - yes, it's a good question. The downvotes may have been for the way the question was originally asked, but it has now been nicely improved. – Prefect

Would be nice with an update to this question. Some years have passed. :) – Brendon

Answer 1

There's a couple of user-space methods (from plugins) that can deal with Opcodes.

• http://uk.php.net/apc_bin_load (and http://uk.php.net/apc_bin_dump)
• http://uk.php.net/bcompiler_read / http://uk.php.net/bcompiler_write_file

Neither produces plain text however because the opcodes are not designed to be a user-writable language (unlike Parrot).

Katt

that means I could overwrite a cached file with apc_bin_load, I guess ... so next question would be how the nice looking opcode statements relate to the actually used binary representation. do you know something about that? references or so? – Borneol

https://mcmap.net/q/262531/-how-to-get-opcodes-of-php has some information, mostly referring to "Vulcan Logic Dumper" - pecl.php.net/package/vld – Katt

Answer 2

There is an extension called ulopcodes that allows you to emit your own opcodes via a function that it exposes to PHP code.

For example:

ulopcodes_emit(ZEND_ECHO, "Hello world!");

Will create that line in the current oparray which will be executed by the VM.

This extension is purely educational and not intended to be used in production code.

(Disclaimer: I am the creator of ulopcodes)

Enclitic

Yes, you can use vld for instance to output the generated opcodes. – Enclitic