Started to break out the parsing of the file's bytes into seperate files.

elf_header.c

@@ -0,0 +1,125 @@
+#include "elf_header.h"
+#include <stdio.h>
+#include <string.h>
+
+#define ELF_IDENTITIFCATION_MAX_SIZE 16
+#define ELF_CLASS_TYPE32 1
+#define ELF_CLASS_TYPE64 2
+
+#define ELF_BYTE_ORDER_LSB 1
+#define ELF_BYTE_ORDER_MSB 2
+
+typedef enum EIdent
+{
+	EI_MAG0 = 0, //Magic number position zero - three.
+	EI_MAG1 = 1,
+	EI_MAG2 = 2,
+	EI_MAG3 = 3,
+	EI_CLASS = 4,
+	EI_DATA = 5,
+	EI_HEADER_VERSION = 6,
+	EI_OSABI = 7,
+	EI_ABIVERSION = 8,
+	EI_PAD = 9,
+	EI_NIDENT = ELF_IDENTITIFCATION_MAX_SIZE - 1, //End of reserved 16 bytes for the header.
+	EI_TYPE = EI_NIDENT + 1,
+	EI_MACHINE = EI_TYPE + 2,
+	EI_OBJECT_FILE_VERSION = EI_MACHINE + 2,
+	EI_ENTRY_ADDRESS_POINT = EI_OBJECT_FILE_VERSION + 4
+} ELFIdentOffsets;
+
+struct elf_header {
+    unsigned char Identitication[ELF_IDENTITIFCATION_MAX_SIZE];
+    uint32_t FileType;
+    uint32_t ISA;
+    uint32_t ELFVersion;
+    uint64_t EntryAddress;
+	uint64_t ProgramHeaderOffset;
+	uint64_t SectionHeaderOffset;
+	uint32_t Flags;
+};
+
+struct elf_header* CreateELFHeader(void);
+int ELFMagicNumberValid(const unsigned char* ident);
+void ELFPrintMagic(const struct elf_header* header);
+
+struct elf_header* ParseObjectFile(const char* bytes, size_t count) {
+    if (count < 0x40) return NULL;
+
+    struct elf_header* header = CreateELFHeader();
+
+    memcpy(header, bytes, ELF_IDENTITIFCATION_MAX_SIZE);
+
+	if (!ELFMagicNumberValid(header->Identitication)) 
+	{
+		fprintf(stderr, "Failed to find ELF magic number in file header.\n");
+        ELFPrintMagic(header);
+        printf("\n");
+
+		return NULL;
+	}
+
+	switch(bytes[EI_CLASS])
+	{
+		case ELF_CLASS_TYPE32:
+			memcpy(&header->EntryAddress, &bytes[EI_ENTRY_ADDRESS_POINT], sizeof(int32_t));
+			break;
+		case ELF_CLASS_TYPE64:
+			memcpy(&header->EntryAddress, &bytes[EI_ENTRY_ADDRESS_POINT], sizeof(int64_t));
+			break;
+		default:
+			header->EntryAddress = -1;
+	}
+
+	switch(bytes[EI_DATA])
+	{
+		case ELF_BYTE_ORDER_LSB:
+			printf("Data: 2's complement, little endian.\n");
+			break;
+		case ELF_BYTE_ORDER_MSB:
+			printf("Data: 2's complement, big endian.\n");
+			break;
+		default:
+			printf("Data: Unknown byte order\n");
+	}
+
+	// int64_t entryAddress;
+
+	// memcpy(&entryAddress, &bytes[EI_ENTRY_ADDRESS_POINT], sizeof(int64_t));
+
+	// printf("Entry point address: %#06lx\n", entryAddress);
+	
+    return header;
+}
+
+int ELFMagicNumberValid(const unsigned char* ident) {
+    char magic[5] = { ident[EI_MAG0], ident[EI_MAG1], ident[EI_MAG2], ident[EI_MAG3], '\0' };
+
+    return strcmp(magic, "\x7f""ELF") == 0;
+}
+
+void ELFPrintMagic(const struct elf_header* header) {
+    if (!header) return;
+
+    printf("Magic: ");
+
+    for(int i = 0; i < ELF_IDENTITIFCATION_MAX_SIZE; i++)
+	{
+		printf("%02X ", header->Identitication[i]);
+	}
+
+	printf("\n");
+}
+
+struct elf_header* CreateELFHeader(void) {
+    struct elf_header* header = calloc(sizeof(struct elf_header), 1);
+
+    if (!header) 
+    {
+        fprintf(stderr, "Failed to calloc\n");
+
+        exit(1);
+    }
+
+    return header;
+}