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chame1eon / jnitrace

A Frida based tool that traces usage of the JNI API in Android apps.
MIT License
1.62k stars 260 forks source link

how to use frida to watch va_list #19

Closed axhlzy closed 3 years ago

axhlzy commented 4 years ago

JNI函数中会存在变长参数，大概看了一下应该处理为pointer

但是具体怎么处理，取得这里面的值的，还请大佬科普一下 /xk

chame1eon commented 4 years ago

Hi,

Thanks for your question. I hope this translates okay. JNI Trace hooks the getMethodID function so it can record how many Java arguments are used in a function. From this, it knows how many values to read from the variable-length parameters.

It is all automated so you do not need to worry about it. If you are using the jnitrace-engine plugin in your own project you get the Java arguments in the callback.

Hope that helps.

Thanks

chame1eon commented 3 years ago

Closing as over 2 weeks old.