Data format in jailbreak device-tree

Question

Data format in jailbreak device-tree

oschanger opened this issue 7 years ago · comments

When i dumped device-tree info on my jailbreak device.I got something like this:
memory-frequency Data <0008af2f 00000000>
I wonder what is this 'Data' format.It's a raw data or memory address.

leoXu · Answer 1 · Mon Dec 25 2017 14:45:32 GMT+0800 (China Standard Time)

Some of the raw data is Base64 encoded

Koan-Sin Tan · Answer 2 · Mon Dec 25 2017 15:44:31 GMT+0800 (China Standard Time)

I have no idea. It seems to me that there is no way to tell/detect the data format of things in device tree nodes. If you know how to do it, please let me know. I'll update code to make data more human readable. For memory-frequency, you probably wanna check https://opensource.apple.com/source/xnu/xnu-4570.1.46/pexpert/arm/pe_identify_machine.c.auto.html

leoXu · Answer 3 · Mon Dec 25 2017 17:10:25 GMT+0800 (China Standard Time)

Em..Can i call DTGetProperty() in some way to get the value or other IOKit api.

Koan-Sin Tan · Answer 4 · Tue Dec 26 2017 09:32:05 GMT+0800 (China Standard Time)

I think we are talking about different things. The device tree information my little program examining is what used by boot loader and passed to the XNU kernel. And you are probably talking about what you get from ioreg. To see how data printed by ioreg are formatted, check its source code. Basically, there are all kinds of guesses. And DTGetProperty() is kernel function provided by Platform Expert. If you can write kernel modules or something like that, you can call it.