Merge pull request #143 from p-x9/feature/enhance-prebuilt-loader

Enhance prebuilt loader

Sources/MachOKit/Model/DyldCache/Loader/ObjCBinaryInfo.swift

@@ -0,0 +1,15 @@
+//
+//  ObjCBinaryInfo.swift
+//  MachOKit
+//
+//  Created by p-x9 on 2024/11/16
+//  
+//
+
+import Foundation
+
+public struct ObjCBinaryInfo: LayoutWrapper {
+    public typealias Layout = objc_binary_info
+
+    public var layout: Layout
+}

Sources/MachOKit/Model/DyldCache/Loader/PrebuiltLoader.swift

@@ -21,9 +21,25 @@ extension PrebuiltLoader {
         layout.loader.isPrebuilt != 0
     }
 
+    public var neverUnload: Bool {
+        layout.loader.neverUnload != 0
+    }
+
+    public var isPremapped: Bool {
+        layout.loader.isPremapped != 0
+    }
+
     public var ref: LoaderRef {
         .init(layout: layout.loader.ref)
     }
+
+    public var uuid: UUID {
+        .init(uuid: layout.loader.uuid)
+    }
+
+    public var sectionLocations: SectionLocations {
+        .init(layout: layout.sectionLocations)
+    }
 }
 
 extension PrebuiltLoader {
@@ -34,6 +50,14 @@ extension PrebuiltLoader {
         return cache.fileHandle.readString(offset: offset)
     }
 
+    public func altPath(in cache: DyldCache) -> String? {
+        guard layout.altPathOffset != 0 else { return nil }
+        guard let offset = cache.fileOffset(
+            of: numericCast(address) + numericCast(layout.altPathOffset)
+        ) else { return nil }
+        return cache.fileHandle.readString(offset: offset)
+    }
+
     public func dependentLoaderRefs(in cache: DyldCache) -> DataSequence<LoaderRef>? {
         guard layout.dependentLoaderRefsArrayOffset != 0,
               let offset = cache.fileOffset(
@@ -46,6 +70,14 @@ extension PrebuiltLoader {
             numberOfElements: numericCast(layout.depCount)
         )
     }
+
+    public func objcBinaryInfo(in cache: DyldCache) -> ObjCBinaryInfo? {
+        guard layout.objcBinaryInfoOffset != 0 else { return nil }
+        guard let offset = cache.fileOffset(
+            of: numericCast(address) + numericCast(layout.objcBinaryInfoOffset)
+        ) else { return nil }
+        return cache.fileHandle.read(offset: offset)
+    }
 }
 
 extension PrebuiltLoader {
@@ -61,6 +93,19 @@ extension PrebuiltLoader {
         )
     }
 
+    public func altPath(in cache: DyldCacheLoaded) -> String? {
+        // swiftlint:disable:previous unused_parameter
+        guard layout.altPathOffset != 0 else { return nil }
+        guard let baseAddress = UnsafeRawPointer(bitPattern: address) else {
+            return nil
+        }
+        return String(
+            cString: baseAddress
+                .advanced(by: numericCast(layout.altPathOffset))
+                .assumingMemoryBound(to: CChar.self)
+        )
+    }
+
     public func dependentLoaderRefs(in cache: DyldCacheLoaded) -> MemorySequence<LoaderRef>? {
         // swiftlint:disable:previous unused_parameter
         guard layout.dependentLoaderRefsArrayOffset != 0,
@@ -74,6 +119,18 @@ extension PrebuiltLoader {
             numberOfElements: numericCast(layout.depCount)
         )
     }
+
+    public func objcBinaryInfo(in cache: DyldCacheLoaded) -> ObjCBinaryInfo? {
+        // swiftlint:disable:previous unused_parameter
+        guard layout.objcBinaryInfoOffset != 0,
+              let baseAddress = UnsafeRawPointer(bitPattern: address) else {
+            return nil
+        }
+        return baseAddress
+            .advanced(by: numericCast(layout.objcBinaryInfoOffset))
+            .assumingMemoryBound(to: ObjCBinaryInfo.self)
+            .pointee
+    }
 }
 
 extension PrebuiltLoader {

Sources/MachOKit/Model/DyldCache/Loader/PrebuiltLoaderProtocol.swift

@@ -17,25 +17,47 @@ public protocol PrebuiltLoaderProtocol {
 
     /// magic of loader starts
     var magic: String? { get }
-    ///  PrebuiltLoader vs JustInTimeLoader
+    /// PrebuiltLoader vs JustInTimeLoader
     var isPrebuilt: Bool { get }
+    var neverUnload: Bool { get }
+    var isPremapped: Bool { get }
+
     var ref: LoaderRef { get }
 
+    // Information for all pre-calculated sections that we know about
+    var sectionLocations: SectionLocations { get }
+
     /// path for target mach-o image
     /// - Parameter cache: DyldCache to which `self` belongs
     /// - Returns: path name
     func path(in cache: DyldCache) -> String?
+    /// alternative path for target mach-o image if install_name does not match real path
+    /// - Parameter cache: DyldCache to which `self` belongs
+    /// - Returns: path name
+    func altPath(in cache: DyldCache) -> String?
     /// loader reference list of target 's dependencies
     /// - Parameter cache: DyldCache to which `self` belongs
     /// - Returns: sequence of loader reference
     func dependentLoaderRefs(in cache: DyldCache) -> DataSequence<LoaderRef>?
+    /// Stores information about the layout of the objc sections in a binary
+    /// - Parameter cache: DyldCache to which `self` belongs
+    /// - Returns: binary info for objc
+    func objcBinaryInfo(in cache: DyldCache) -> ObjCBinaryInfo?
 
     /// path for target mach-o image
     /// - Parameter cache: DyldCacheLoaded to which `self` belongs
     /// - Returns: path name
     func path(in cache: DyldCacheLoaded) -> String?
+    /// alternative path for target mach-o image if install_name does not match real path
+    /// - Parameter cache: DyldCacheLoaded to which `self` belongs
+    /// - Returns: path name
+    func altPath(in cache: DyldCacheLoaded) -> String?
     /// loader reference list of target 's dependencies
     /// - Parameter cache: DyldCacheLoaded to which `self` belongs
     /// - Returns: sequence of loader reference
     func dependentLoaderRefs(in cache: DyldCacheLoaded) -> MemorySequence<LoaderRef>?
+    /// Stores information about the layout of the objc sections in a binary
+    /// - Parameter cache: DyldCacheLoaded to which `self` belongs
+    /// - Returns: binary info for objc
+    func objcBinaryInfo(in cache: DyldCacheLoaded) -> ObjCBinaryInfo?
 }

Sources/MachOKit/Model/DyldCache/Loader/PrebuiltLoader_Pre1165_3.swift

@@ -19,9 +19,21 @@ extension PrebuiltLoader_Pre1165_3 {
         layout.loader.isPrebuilt != 0
     }
 
+    public var neverUnload: Bool {
+        layout.loader.neverUnload != 0
+    }
+
+    public var isPremapped: Bool {
+        layout.loader.isPremapped != 0
+    }
+
     public var ref: LoaderRef {
         .init(layout: layout.loader.ref)
     }
+
+    public var sectionLocations: SectionLocations {
+        .init(layout: layout.sectionLocations)
+    }
 }
 
 extension PrebuiltLoader_Pre1165_3 {
@@ -32,6 +44,14 @@ extension PrebuiltLoader_Pre1165_3 {
         return cache.fileHandle.readString(offset: offset)
     }
 
+    public func altPath(in cache: DyldCache) -> String? {
+        guard layout.altPathOffset != 0 else { return nil }
+        guard let offset = cache.fileOffset(
+            of: numericCast(address) + numericCast(layout.altPathOffset)
+        ) else { return nil }
+        return cache.fileHandle.readString(offset: offset)
+    }
+
     public func dependentLoaderRefs(in cache: DyldCache) -> DataSequence<LoaderRef>? {
         guard layout.dependentLoaderRefsArrayOffset != 0,
               let offset = cache.fileOffset(
@@ -44,6 +64,14 @@ extension PrebuiltLoader_Pre1165_3 {
             numberOfElements: numericCast(layout.depCount)
         )
     }
+
+    public func objcBinaryInfo(in cache: DyldCache) -> ObjCBinaryInfo? {
+        guard layout.objcBinaryInfoOffset != 0 else { return nil }
+        guard let offset = cache.fileOffset(
+            of: numericCast(address) + numericCast(layout.objcBinaryInfoOffset)
+        ) else { return nil }
+        return cache.fileHandle.read(offset: offset)
+    }
 }
 
 extension PrebuiltLoader_Pre1165_3 {
@@ -59,6 +87,19 @@ extension PrebuiltLoader_Pre1165_3 {
         )
     }
 
+    public func altPath(in cache: DyldCacheLoaded) -> String? {
+        // swiftlint:disable:previous unused_parameter
+        guard layout.altPathOffset != 0 else { return nil }
+        guard let baseAddress = UnsafeRawPointer(bitPattern: address) else {
+            return nil
+        }
+        return String(
+            cString: baseAddress
+                .advanced(by: numericCast(layout.altPathOffset))
+                .assumingMemoryBound(to: CChar.self)
+        )
+    }
+
     public func dependentLoaderRefs(in cache: DyldCacheLoaded) -> MemorySequence<LoaderRef>? {
         // swiftlint:disable:previous unused_parameter
         guard layout.dependentLoaderRefsArrayOffset != 0,
@@ -72,6 +113,18 @@ extension PrebuiltLoader_Pre1165_3 {
             numberOfElements: numericCast(layout.depCount)
         )
     }
+
+    public func objcBinaryInfo(in cache: DyldCacheLoaded) -> ObjCBinaryInfo? {
+        // swiftlint:disable:previous unused_parameter
+        guard layout.objcBinaryInfoOffset != 0,
+              let baseAddress = UnsafeRawPointer(bitPattern: address) else {
+            return nil
+        }
+        return baseAddress
+            .advanced(by: numericCast(layout.objcBinaryInfoOffset))
+            .assumingMemoryBound(to: ObjCBinaryInfo.self)
+            .pointee
+    }
 }
 
 extension PrebuiltLoader_Pre1165_3 {

Sources/MachOKit/Model/DyldCache/Loader/SectionLocations.swift

@@ -0,0 +1,77 @@
+//
+//  SectionLocations.swift
+//  MachOKit
+//
+//  Created by p-x9 on 2024/11/16
+//  
+//
+
+import Foundation
+
+public struct SectionLocations: LayoutWrapper {
+    public typealias Layout = section_locations
+
+    public var layout: Layout
+}
+
+extension SectionLocations {
+    // [dyld implementation](https://github.com/apple-oss-distributions/dyld/blob/65bbeed63cec73f313b1d636e63f243964725a9d/include/mach-o/dyld_priv.h#L62)
+    public enum SectionKind: Int, CaseIterable {
+        // TEXT:
+        case text_swift5_protos
+        case text_swift5_proto
+        case text_swift5_types
+        case text_swift5_replace
+        case text_swift5_replace2
+        case text_swift5_ac_funcs
+
+        // DATA*:
+        case objc_image_info
+        case data_sel_refs
+        case data_msg_refs
+        case data_class_refs
+        case data_super_refs
+        case data_protocol_refs
+        case data_class_list
+        case data_non_lazy_class_list
+        case data_stub_list
+        case data_category_list
+        case data_category_list2
+        case data_non_lazy_category_list
+        case data_protocol_list
+        case data_objc_fork_ok
+        case data_raw_isa
+
+        // ~~ version 1 ~~
+    }
+}
+
+extension SectionLocations {
+    public struct Section {
+        public let offset: Int
+        public let size: Int
+        public let kind: SectionKind
+    }
+}
+
+extension SectionLocations {
+    public func section(for kind: SectionKind) -> Section {
+        var offsets = layout.offsets
+        var sizes = layout.sizes
+        let offset = withUnsafePointer(to: &offsets) {
+            UnsafeRawPointer($0)
+                .assumingMemoryBound(to: UInt64.self)
+                .advanced(by: kind.rawValue).pointee
+        }
+        let size = withUnsafePointer(to: &sizes) {
+            UnsafeRawPointer($0)
+                .assumingMemoryBound(to: UInt64.self)
+                .advanced(by: kind.rawValue).pointee
+        }
+        return .init(
+            offset: numericCast(offset),
+            size: numericCast(size),
+            kind: kind
+        )
+    }
+}

Sources/MachOKitC/include/dyld_cache_loader.h

@@ -9,6 +9,7 @@
 #ifndef dyld_cache_loader_h
 #define dyld_cache_loader_h
 
+#include <stdbool.h>
 // https://github.com/apple-oss-distributions/dyld/blob/d552c40cd1de105f0ec95008e0e0c0972de43456/dyld/PrebuiltLoader.h#L254
 struct prebuilt_loader_set {
     uint32_t    magic;
@@ -175,7 +176,55 @@ struct prebuilt_loader {
     uint32_t            overrideBindTargetRefsOffset;
     uint32_t            overrideBindTargetRefsCount;
 
-    // struct section_locations    sectionLocations;
+     struct section_locations    sectionLocations;
+};
+
+// https://github.com/apple-oss-distributions/dyld/blob/65bbeed63cec73f313b1d636e63f243964725a9d/dyld/PrebuiltLoader.h#L344
+// Stores information about the layout of the objc sections in a binary, as well as other properties relating to
+// the objc information in there.
+struct objc_binary_info {
+    // Offset to the __objc_imageinfo section
+    uint64_t imageInfoRuntimeOffset;
+
+    // Offsets to sections containing objc pointers
+    uint64_t selRefsRuntimeOffset;
+    uint64_t classListRuntimeOffset;
+    uint64_t categoryListRuntimeOffset;
+    uint64_t protocolListRuntimeOffset;
+
+    // Counts of the above sections.
+    uint32_t selRefsCount;
+    uint32_t classListCount;
+    uint32_t categoryCount;
+    uint32_t protocolListCount;
+
+    // Do we have stable Swift fixups to apply to at least one class?
+    bool     hasClassStableSwiftFixups;
+
+    // Do we have any pointer-based method lists to set as uniqued?
+    bool     hasClassMethodListsToSetUniqued;
+    bool     hasCategoryMethodListsToSetUniqued;
+    bool     hasProtocolMethodListsToSetUniqued;
+
+    // Do we have any method lists in which to set selector references.
+    // Note we only support visiting selector refernces in pointer based method lists
+    // Relative method lists should have been verified to always point to __objc_selrefs
+    bool     hasClassMethodListsToUnique;
+    bool     hasCategoryMethodListsToUnique;
+    bool     hasProtocolMethodListsToUnique;
+
+    // Whwn serialized to the PrebuildLoader, these fields will encode other information about
+    // the binary.
+
+    // Offset to an array of uint8_t's.  One for each protocol.
+    // Note this can be 0 (ie, have no fixups), even if we have protocols.  That would be the case
+    // if this binary contains no canonical protocol definitions, ie, all canonical defs are in other binaries
+    // or the shared cache.
+    uint32_t protocolFixupsOffset;
+    // Offset to an array of BindTargetRef's.  One for each selector reference to fix up
+    // Note we only fix up selector refs in the __objc_selrefs section, and in pointer-based method lists
+    uint32_t selectorReferencesFixupsOffset;
+    uint32_t selectorReferencesFixupsCount;
 };
 
 #endif /* dyld_cache_loader_h */