From 12777e29c6027728b47f2db6712aa6e7f15fc9e8 Mon Sep 17 00:00:00 2001 From: Anselm Levskaya Date: Sun, 19 Oct 2014 15:49:33 -0700 Subject: [PATCH] Works on modern browsers again, updated readme to reflect this. --- readme.md | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/readme.md b/readme.md index 3de3451..e5e11c0 100644 --- a/readme.md +++ b/readme.md @@ -3,37 +3,39 @@ De-obfuscated JSLinux I wanted to understand how the amazing [JsLinux][1] worked. -However the original was passed through a minifier and was completely incomprehensible in that form. (Mr Bellard's standards for the code that he open sources is very high.) I couldn't wait for the proper release of the opus, so in a fit of mania I hand de-obfuscated the codebase (primarily the core cpu-emulation -routines and a bit of the rest as well) while studying it over a few days' time. +However the original was passed through a minifier and was completely incomprehensible in that form. (Mr Bellard's standards for the code that he open sources is very high.) I couldn't wait for the proper release of the opus, so in a fit of mania I hand de-obfuscated the codebase (primarily the core cpu-emulation routines and a bit of the rest as well) while studying it over a few days' time. -In the off-chance someone else might be interested in this code as a -basis for further weird in-browser x86 hacking I'm posting this +In the off-chance someone else might be interested in this code as a basis for further weird in-browser x86 hacking I'm posting this redacted version of the code here, with permission of Mr. Bellard. -Note that there is a much more readable, ground-up project to build an open-source 386-style emulator in javascript called [jslm32][3]. +Note that there is another ground-up project to build an open-source 386-style emulator in javascript called [jslm32][3]. +I also recommend looking at the remarkable linux on [jor1k][5] emulator project. ### Status -The current codebase won't run on recent webkit browsers due to a breaking change in the way Synchronous [XHR][4] requests are handled. The binary loading routines need to be rewritten to be asynchronous, not terribly hard but annoying enough that I haven't just done it. (Fabrice's original online version has been patched and runs fine.) +The current codebase should run on most modern versions of Chrome, Safari, and Firefox. If you're running it locally, you will need to load it via a local server to allow the XHR requests to load the binaries. -jslinux-deobfuscated is still a dense code base, it's an emulator of a rather -complicated architecture, after all. However this version is nowhere -near so incomprehensible as the original. Nearly all of the global variables -and function names have been named somewhat sensibly. Many comments -have been added. +jslinux-deobfuscated is still a dense, messy code base from any pedagogic point of view. However for those interested in Mr. Bellard's code, +this version is nowhere near so incomprehensible as the original. Nearly all of the global variables and function names have been named +somewhat sensibly. Many pointers to references have been added to the source. -The core opcode execution loop has been autocommented to indicate what -instruction operation the opcode refers to. +The core opcode execution loop has been commented to indicate what instruction the opcode refers to. + +### Unresolved One mystery is, why does CPUID(1) return 8 << 8 in EBX? EBX[15:8] is now used to indicate CLFLUSH line size, but that field must have been used for something else in the past. +The CALL/RET/INT/IRET routines are still quite confused and haven't yet been rewritten. The code dealing with segmentation, and some of the code for real-mode remains relatively messy. + +Any recommendations / clarifications are welcome! + ### ETC I highly recommend, by the way, the excellent [JSShaper][2] library for transforming large javascript code bases. The hacks I made from it are in this repo: a little symbol-name-transformer node.js script and an emacs function for doing this in live buffers. ### License -This is a pedagogical/aesthetic derivative of the original JSLinux code Copyright (c) 2011-2013 Fabrice Bellard. It is posted here with permission of the original author subject to his original constraints : Redistribution or commercial use is prohibited without the (original) author's permission. +This is a pedagogical/aesthetic derivative of the original JSLinux code Copyright (c) 2011-2014 Fabrice Bellard. It is posted here with permission of the original author subject to his original constraints : Redistribution or commercial use is prohibited without the (original) author's permission. ### References Some other helpful references for understanding what's going on: @@ -59,3 +61,4 @@ Some other helpful references for understanding what's going on: [2]: http://jsshaper.org [3]: https://github.com/ubercomp/jslm32 [4]: https://bugs.webkit.org/show_bug.cgi?id=72154 +[5]: https://github.com/s-macke/jor1k