Analysis of the Technical Principles of the Smali Framework in Java Class Libraries)

Analysis of Smali framework technical principles in the Java class library Overview: Smali is a technology used to compile, modify, and reintegrate DEX (DALVIK Executable) files for the Android platform.It is a tool based on the Java language development, which aims to help developers better understand and analyze the existing Dex files and perform necessary modifications and debugging.This article will analyze the technical principles of the Smali framework in the Java library, including generating Smali code and related configuration. Smali framework technical principle: 1. Capable Dex file: The Smali framework converts it to the Smali code by relying DEX file to further analyze and modify it.Reverse assembly operations can be implemented using dex2jar and other tools. 2. Smali code generation: Smali code is a code similar to the assembly language to describe the Dalvik virtual machine set.The Smali framework analyzes and analyzes the dex file of the counter to generate the corresponding Smali code.The process of generating the Smali code involves analysis and mapping of elements such as class, methods, fields such as the DEX file. 3. Grammar analysis: The Smali framework analyzes and analyzes the generated Smali code based on the specified grammar.It can recognize and explain different Smali instructions, including classes, methods and calls, and field declarations and access. 4. Code modification: The Smali framework provides a set of API to modify and write Smali code.Developers can add, delete or modify the Smali instructions by calling the corresponding API to achieve customized processing of DEX files.Common modification operations include the execution logic of the change method, adding new methods and fields, etc. 5. Re -assemble DEX file: After modifying the Smali code, the Smali framework will re -assembled the generated Smali code to return the dex file format.This involves converting Smali code into a corresponding binary format and generates a new DEX file. Code example: The following is a simple example, which shows the logic of a method to modify a method in the DEX file using the Smali framework: smali .method public static addTwoNumbers(II)I .registers 4 if-nez p0, :cond_0 if-nez p1, :cond_0 const/4 v0, 1 return v0 :cond_0 add-int p2, p0, p1 return p2 .end method In the above examples, we use the Smali code to modify the addtwonumbers method.The modification logic is that when the input parameters P0 and P1 are 0, return 1; otherwise, return the sum of P0 and P1. Related configuration: Use the Smali framework for debugging and analysis requires some related configurations, including: 1. Installation and configuration Smali framework: Developers need to download the Smali framework and install configuration.The installation and configuration process of the Smali framework can refer to the official documentation. 2. Capable DEX file: By using DEX2JAR and other tools, the target DEX file is compiled to Smali code. 3. Modification and re -compilation: After modifying the Smali code, use the Smali framework to re -assemble the modified Smali code into a new DEX file. Summarize: The Smali framework is a technique for analysis and modification of the DEX file that analyzes and modify the Android platform.Through the steps of dex files, generating Smali code, syntax analysis, code modification, and re -assembly, developers can customize the DEX file.The use of the Smali framework requires a certain configuration and understand the grammatical rules of Smali code.By mastering the technical principles of the Smali framework, developers can better understand and modify the existing Dex files to meet their needs.