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 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<CChar> 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:
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 for rebinding indirect symbols.
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
ImageSymbolswhich 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 dictionaries.A couple of
ImageSymbolssubclasses represent groups of images such asDLKit.allImagesfor all images loaded in an application orDLKit.appImagesfor this list of images filtered to include only those in the app bundle.To look up a symbol use the allImages pseudo image:
Or you can find the symbol and wrapped image for an address:
There is a typealias of
UnsafePointer<CChar>toImageSymbols.SymbolNameand an extension on this typealias to"demangle"Swift symbols to the Swift language representation of the symbol. There is also a methodmangleon an image which can “re-mangle” this representation to a symbol name provided the symbol is defined or referred to in the image.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:
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 for rebinding indirect symbols.
Date:2023/03/03