karina
81 lines
2.5 KiB
Swift
81 lines
2.5 KiB
Swift
struct FDTHeader {
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let magic: UInt32 // 0xd00dfeed
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let totalsize: UInt32
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let off_dt_struct: UInt32
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let off_dt_strings: UInt32
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let off_mem_rsvmap: UInt32
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let version: UInt32
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let last_comp_version: UInt32
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let boot_cpuid_phys: UInt32
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let size_dt_strings: UInt32
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let size_dt_struct: UInt32
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}
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struct FDTProperty {
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let len: UInt32
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let nameoff: UInt32
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}
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enum FDTToken: UInt32 {
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case beginNode = 0x1
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case endNode = 0x2
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case prop = 0x3
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case nop = 0x4
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case end = 0x9
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}
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extension UInt32 {
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var fromBe: UInt32 {
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return self.byteSwapped
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}
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}
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func alignUp(_ value: Int, to: Int) -> Int {
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return (value + to - 1) & ~(to - 1)
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}
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let kFDTHeaderMagic = 0xd00dfeed
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func parseDTB(at pointer: UnsafeRawPointer) {
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let header = pointer.bindMemory(to: FDTHeader.self, capacity: 1).pointee
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guard header.magic.byteSwapped == kFDTHeaderMagic else {
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return
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}
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let structOffset = Int(header.off_dt_struct.byteSwapped)
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let stringOffset = Int(header.off_dt_strings.byteSwapped)
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var structBase = pointer.advanced(by: structOffset)
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let stringsBase = pointer.advanced(by: stringOffset)
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var finished = false
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while !finished {
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let rawToken = structBase.load(as: UInt32.self).byteSwapped
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structBase = structBase.advanced(by: 4)
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if let token = FDTToken(rawValue: rawToken) {
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switch token {
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case .beginNode:
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let namePointer = structBase.assumingMemoryBound(to: UInt8.self)
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let name = String(cString: namePointer)
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let nameLength = name.utf8.count + 1
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structBase = structBase.advanced(by: alignUp(nameLength, to: 4))
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case .prop:
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let propertyHeader = structBase.load(as: FDTProperty.self)
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let dataLength = Int(propertyHeader.len.byteSwapped)
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let nameOffset = Int(propertyHeader.nameoff.byteSwapped)
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let namePointer = stringsBase.advanced(by: nameOffset).assumingMemoryBound(to: UInt8.self)
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structBase = structBase.advanced(by: 8) // skip header
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structBase = structBase.advanced(by: alignUp(dataLength, to: 4)) // skip data for now
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case .endNode:
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continue
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case .nop:
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continue
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case .end:
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finished = true
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}
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}
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}
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} |