added ELF header and parser

2026-07-31 11:20:03 +00:00 · 2025-02-25 14:41:15 -08:00
parent 87ae363292
commit b74c304f39
4 changed files with 1254 additions and 0 deletions
@@ -0,0 +1,90 @@
+// Copyright (c) 2025 Epic Games Tools
+// Licensed under the MIT license (https://opensource.org/license/mit/)
+
+internal B32
+elf_check_magic(String8 data)
+{
+  U8 sig[ELF_Identifier_Max] = {0};
+  str8_deserial_read(data, 0, &sig[0], sizeof(sig), 1);
+  B32 is_magic_valid = (sig[ELF_Identifier_Mag0] == 0x7f && sig[ELF_Identifier_Mag1] == 'E'  && sig[ELF_Identifier_Mag2] == 'L'  && sig[ELF_Identifier_Mag3] == 'F');
+  return is_magic_valid;
+}
+
+internal ELF_BinInfo
+elf_bin_from_data(String8 data)
+{
+  ELF_Hdr64 hdr64         = {0};
+  Rng1U64   sh_name_range = rng_1u64(0,0);
+
+  if (elf_check_magic(data)) {
+    U8 sig[ELF_Identifier_Max] = {0};
+    str8_deserial_read(data, 0, &sig[0], sizeof(sig), 1);
+
+    switch (sig[ELF_Identifier_Class]) {
+    case ELF_Class_None: break;
+    case ELF_Class_32: {
+      ELF_Hdr32 hdr32    = {0};
+      U64       hdr_size = str8_deserial_read_struct(data, 0, &hdr32);
+      if (hdr_size == sizeof(hdr32)) {
+        hdr64  = elf_hdr64_from_hdr32(hdr32);
+
+        U64        shstr_off = hdr32.e_shoff + hdr32.e_shentsize*hdr32.e_shstrndx;
+        ELF_Shdr32 shdr      = {0};
+        U64        shdr_size = str8_deserial_read_struct(data, shstr_off, &shdr);
+
+        if (shdr_size == sizeof(shdr)) {
+          sh_name_range = rng_1u64(shdr.sh_offset, shdr.sh_offset + shdr.sh_size);
+        }
+      }
+    } break;
+    case ELF_Class_64: {
+      U64 hdr_size = str8_deserial_read_struct(data, 0, &hdr64);
+      if (hdr_size == sizeof(hdr64)) {
+        U64        shstr_off = hdr64.e_shoff + hdr64.e_shentsize*hdr64.e_shstrndx;
+        ELF_Shdr64 shdr      = {0};
+        U64        shdr_size = str8_deserial_read_struct(data, shstr_off, &shdr);
+
+        if (shdr_size == sizeof(shdr)) {
+          sh_name_range = rng_1u64(shdr.sh_offset, shdr.sh_offset + shdr.sh_size);
+        }
+      }
+    } break;
+    default: Assert(!"invalid elf header"); break;
+    } 
+  }
+  
+  ELF_BinInfo info   = {0};
+  info.hdr           = hdr64;
+  info.sh_name_range = sh_name_range;
+  
+  return info;
+}
+
+internal ELF_Shdr64Array
+elf_shdr64_array_from_bin(Arena *arena, String8 raw_data, ELF_Hdr64 *hdr)
+{
+  Rng1U64 shdr_range = rng_1u64(hdr->e_shoff, hdr->e_shoff + hdr->e_shentsize*hdr->e_shnum);
+  String8 shdr_data  = str8_substr(raw_data, shdr_range);
+  
+  ELF_Shdr64Array result = {0};
+  result.count           = hdr->e_shnum;
+  result.v               = push_array(arena, ELF_Shdr64, hdr->e_shnum);
+  
+  for(U64 shdr_idx = 0; shdr_idx < hdr->e_shnum; ++shdr_idx) {
+    switch (hdr->e_ident[ELF_Identifier_Class]) {
+    case ELF_Class_None: break;
+    case ELF_Class_32: {
+      ELF_Shdr32 shdr32 = {0};
+      str8_deserial_read_struct(shdr_data, shdr_idx * sizeof(ELF_Shdr32), &shdr32);
+      result.v[shdr_idx] = elf_shdr64_from_shdr32(shdr32);
+    } break;
+    case ELF_Class_64: {
+      str8_deserial_read_struct(shdr_data, shdr_idx * sizeof(ELF_Shdr64), &result.v[shdr_idx]);
+    } break;
+    default: InvalidPath; break;
+    }
+  }
+  
+  return result;
+}
+