Add Elf dynamic support

Author: kiwidoggie

src/LibObjectFile/Elf/ElfSectionHeaderTable.cs

@@ -133,6 +133,7 @@ private static ElfSection CreateElfSection(ElfReader reader, uint sectionIndex,
             ElfSectionType.Note => new ElfNoteTable(),
             ElfSectionType.SymbolTableSectionHeaderIndices => new ElfSymbolTableSectionHeaderIndices(),
             ElfSectionType.NoBits => new ElfNoBitsSection(),
+            ElfSectionType.DynamicLinking => new ElfDynamicLinkingTable(),
             _ => new ElfStreamSection(sectionType)
         };
     }

src/LibObjectFile/Elf/Sections/ElfDynamic.cs

@@ -0,0 +1,32 @@
+// Copyright (c) Alexandre Mutel. All rights reserved.
+// This file is licensed under the BSD-Clause 2 license.
+// See the license.txt file in the project root for more information.
+
+namespace LibObjectFile.Elf
+{
+    /// <summary>
+    /// Dynamic table entry for ELF.
+    /// </summary>
+    public record struct ElfDynamic
+    {
+        /// <summary>
+        /// Type of dynamic table entry.
+        /// </summary>
+        public long Tag { get; set; }
+
+        /// <summary>
+        /// Integer value of entry.
+        /// </summary>
+        public ulong Value { get; set; }
+
+        /// <summary>
+        /// Pointer value of entry.
+        /// </summary>
+        public ulong Pointer => Value;
+
+        /// <summary>
+        /// Dynamic Tag
+        /// </summary>
+        public ElfDynamicTag TagType => (ElfDynamicTag)Tag;
+    }
+}

src/LibObjectFile/Elf/Sections/ElfDynamicLinkingTable.cs

@@ -0,0 +1,158 @@
+// Copyright (c) Alexandre Mutel. All rights reserved.
+// This file is licensed under the BSD-Clause 2 license.
+// See the license.txt file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using LibObjectFile.Diagnostics;
+using LibObjectFile.IO;
+
+namespace LibObjectFile.Elf
+{
+    public class ElfDynamicLinkingTable : ElfSection
+    {
+        private Stream _stream;
+        private bool _is32;
+
+        public Stream Stream
+        {
+            get => _stream;
+            set
+            {
+                ArgumentNullException.ThrowIfNull(value);
+                _stream = value;
+                Size = (ulong)_stream.Length;
+            }
+        }
+
+        public List<ElfDynamic> Entries { get; }
+
+        public ElfDynamicLinkingTable() : base(ElfSectionType.DynamicLinking)
+        {
+            Name = ElfSectionSpecialType.Dynamic.GetDefaultName();
+            Flags = ElfSectionSpecialType.Dynamic.GetSectionFlags();
+            _stream = new MemoryStream();
+
+            Entries = [];
+        }
+
+        public override void Read(ElfReader reader)
+        {
+            reader.Position = Position;
+            Entries.Clear();
+
+            var numberOfEntries = (int)(base.Size / base.TableEntrySize);
+            var entries = Entries;
+            CollectionsMarshal.SetCount(entries, numberOfEntries);
+
+            if (_is32)
+                Read32(reader, numberOfEntries);
+            else
+                Read64(reader, numberOfEntries);
+        }
+
+        private void Read32(ElfReader reader, int numberOfEntries)
+        {
+            using var batch = new BatchDataReader<ElfNative.Elf32_Dyn>(reader.Stream, numberOfEntries);
+            var span = CollectionsMarshal.AsSpan(Entries);
+            ref var entry = ref MemoryMarshal.GetReference(span);
+            while (batch.HasNext())
+            {
+                ref var dyn = ref batch.Read();
+
+                entry.Tag = reader.Decode(dyn.d_tag);
+                entry.Value = reader.Decode(dyn.d_un.d_val);
+
+                entry = ref Unsafe.Add(ref entry, 1);
+            }
+        }
+
+        private void Read64(ElfReader reader, int numberOfEntries)
+        {
+            using var batch = new BatchDataReader<ElfNative.Elf64_Dyn>(reader.Stream, numberOfEntries);
+            var span = CollectionsMarshal.AsSpan(Entries);
+            ref var entry = ref MemoryMarshal.GetReference(span);
+            while (batch.HasNext())
+            {
+                ref var dyn = ref batch.Read();
+
+                entry.Tag = reader.Decode(dyn.d_tag);
+                entry.Value = reader.Decode(dyn.d_un.d_val);
+
+                entry = ref Unsafe.Add(ref entry, 1);
+            }
+        }
+
+        public override void Write(ElfWriter writer)
+        {
+            if (_is32)
+                Write32(writer);
+            else
+                Write64(writer);
+        }
+
+        private void Write32(ElfWriter writer)
+        {
+            var entries = CollectionsMarshal.AsSpan(Entries);
+            using var batch = new BatchDataWriter<ElfNative.Elf32_Dyn>(writer.Stream, entries.Length);
+            var dyn = new ElfNative.Elf32_Dyn();
+            for (int i = 0; i < entries.Length; i++)
+            {
+                ref var entry = ref entries[i];
+
+                writer.Encode(out dyn.d_tag, (int)entry.Tag);
+                writer.Encode(out dyn.d_un.d_val, (uint)entry.Value);
+
+                batch.Write(dyn);
+            }
+        }
+
+        private void Write64(ElfWriter writer)
+        {
+            var entries = CollectionsMarshal.AsSpan(Entries);
+            using var batch = new BatchDataWriter<ElfNative.Elf64_Dyn>(writer.Stream, entries.Length);
+            var dyn = new ElfNative.Elf64_Dyn();
+            for (int i = 0; i < entries.Length; i++)
+            {
+                ref var entry = ref entries[i];
+
+                writer.Encode(out dyn.d_tag, entry.Tag);
+                writer.Encode(out dyn.d_un.d_val, entry.Value);
+
+                batch.Write(dyn);
+            }
+        }
+
+        protected override unsafe void ValidateParent(ObjectElement parent)
+        {
+            base.ValidateParent(parent);
+
+            var elf = (ElfFile)parent;
+            _is32 = elf.FileClass == ElfFileClass.Is32;
+
+            BaseTableEntrySize = (uint)(_is32 ? sizeof(ElfNative.Elf32_Dyn) : sizeof(ElfNative.Elf64_Dyn));
+            AdditionalTableEntrySize = 0;
+        }
+
+        internal override unsafe void InitializeEntrySizeFromRead(DiagnosticBag diagnostics, ulong entrySize, bool is32)
+        {
+            _is32 = is32;
+
+            if (is32)
+                throw new NotImplementedException();
+            else
+            {
+                if (entrySize != (ulong)sizeof(ElfNative.Elf64_Dyn))
+                    diagnostics.Error(DiagnosticId.ELF_ERR_InvalidSectionEntrySize, $"Invalid size [{entrySize}] for dynamic entry. Expecting to be equal to [{sizeof(ElfNative.Elf64_Dyn)}] bytes.");
+                else
+                {
+                    BaseTableEntrySize = (uint)sizeof(ElfNative.Elf64_Dyn);
+                    AdditionalTableEntrySize = (uint)(entrySize - AdditionalTableEntrySize);
+                }
+            }
+        }
+    }
+}