https://github.com/johnno1962/DLKit

A rather subscript oriented interface to the dynamic linker.
https://github.com/johnno1962/DLKit

Last synced: 3 months ago
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A rather subscript oriented interface to the dynamic linker.

• Host: GitHub
• URL: https://github.com/johnno1962/DLKit
• Owner: johnno1962
• License: mit
• Created: 2021-04-19T14:45:36.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2024-04-16T11:19:57.000Z (7 months ago)
• Last Synced: 2024-05-02T00:54:29.685Z (7 months ago)
• Language: Swift
• Homepage:
• Size: 42 KB
• Stars: 22
• Watchers: 5
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# DLKit

### A subscript oriented interface to the symbol tables maintained by the dynamic linker.

DLKit is intended to be a "Swifty" encapsulation of the dynamic linker APIs gleaned from

assorted manual pages and system headers. Loaded images (the main executable

or frameworks) are wrapped in the class `ImageSymbols` which you can use to lookup

symbols or find the symbol at an address less than or equal to a pointer and it's

wrapped image. ImageSymbols instances can also be iterated over in a loop

to find all symbol definitions in that image. Think of them as representing

the image/object file as bi-directional dictionaries.

A couple of `ImageSymbols` subclasses represent groups of images such as

`DLKit.allImages` for all images loaded in an application or `DLKit.appImages`

for this list of images filtered to include only those in the app bundle.

To look up a symbol use the allImages pseudo image:

```

if let pointer = DLKit.allImages["main"] {

```

Or you can find the symbol and wrapped image for an address:

```

if let (name, image) = DLKit.allImages[pointer] else {

```

There is a typealias of `UnsafePointer` to `ImageSymbols.SymbolName` 

and an extension on this typealias to `"demangle"` Swift symbols to

the Swift language representation of the symbol. There is also a method 

`mangle` on an image which can "re-mangle" this representation to a

symbol name provided the symbol is defined or referred to in the image.

```

let swift = name.demangled

let name = image.mangle(swift: swift)

```

The subscript operators are settable and you can also "rebind" or "interpose"

a symbol in your application by assigning it to point to a new implementation:

```

DLKit.appImages["function_name"] = new_implementation

```

This "rebinding" works across framework boundaries or inside an application if it has 

been linked with "Other Linker Flags" -Xlinker -interposable and uses facebook's

[fishhook](https://github.com/facebook/fishhook) for rebinding indirect symbols.

$Date: 2024/04/03 $