Add file header parsing for x86 32 and 64 bit archs

src/main.rs

@@ -2,13 +2,19 @@
 // Author: Garrett Dickinson
 // Created: 01/23/2023
 // Description: Main entrypoint script for chisel. Contains basic procedures
-//              for gathering ELF file data.
-
+//              for gathering ELF file and program data.
 
 use std::path;
 use std::env;
 use std::fs;
 use std::process::exit;
+use std::collections::HashMap;
+
+
+// ELF Header Sizes
+
+const ELF_FILE_HEADER_LENGTH: [u8; 2] = [0x34, 0x40];
+
 
 // Generic ELF information offsets.
 
@@ -20,20 +26,20 @@ const ELF_TYPE_OFFSET: u8 = 0x10;       // Object type identifier; 2 bytes
 const ELF_MACHINE_OFFSET: u8 = 0x12;    // Instruction set type; 2 bytes
 
 
-// Entry points and program header table inforamtion.
-// Tupled offset are split by architecture:
+// Offsets for file header entry points and table inforamtion.
+// Arrayed offset are split by architecture:
 //      0 : x86
 //      1 : x86_64
 
 const ELF_ENTRYPOINT_OFFSET: u8 = 0x18;
-const ELF_PHOFF_OFFSET: (u8, u8) = (0x1C, 0x20);        // Program header table pointer; 2 bytes
-const ELF_SHOFF_OFFSET: (u8, u8) = (0x20, 0x28);        // Section table pointer; 2 bytes
-const ELF_EHSIZE_OFFSET: (u8, u8) = (0x28, 0x34);       // Program header table entry size pointer; 2 bytes
-const ELF_PHENTSIZE_OFFSET: (u8, u8) = (0x28, 0x34);    // Section table pointer; 2 bytes
-const ELF_PHNUM_OFFSET: (u8, u8) = (0x2C, 0x38);
-const ELF_SHENTSIZE_OFFSET: (u8, u8) = (0x2E, 0x3A);
-const ELF_SHNUM_OFFSET: (u8, u8) = (0x30, 0x3C);
-const ELF_SHSTRNDX_OFFSET: (u8, u8) = (0x32, 0x3E);
+const ELF_PHOFF_OFFSET: [u8; 2] = [0x1C, 0x20];        // Program header table pointer; 2 bytes
+const ELF_SHOFF_OFFSET: [u8; 2] = [0x20, 0x28];        // Section table pointer; 2 bytes
+const ELF_EHSIZE_OFFSET: [u8; 2] = [0x28, 0x34];       // Program header table entry size pointer; 2 bytes
+const ELF_PHENTSIZE_OFFSET: [u8; 2] = [0x28, 0x34];    // Section table pointer; 2 bytes
+const ELF_PHNUM_OFFSET: [u8; 2] = [0x2C, 0x38];        // Program header table number of entries pointer; 2 bytes
+const ELF_SHENTSIZE_OFFSET: [u8; 2] = [0x2E, 0x3A];    // Size of section header table; 2 bytes
+const ELF_SHNUM_OFFSET: [u8; 2] = [0x30, 0x3C];        // Number of entries in section table pointer; 2 bytes
+const ELF_SHSTRNDX_OFFSET: [u8; 2] = [0x32, 0x3E];     // Index of section header that contains names; 2 bytes
 
 
 fn main() {
@@ -41,7 +47,13 @@ fn main() {
     let args: Vec<String> = env::args().collect();
 
     // Grab our filepath from our options
-    let file_path = &args[1];
+    if &args.len() < &2 {
+        // No file given, terminate
+        println!("[Error] Please provied a file to open...");
+        exit(0);
+    }
+
+    let file_path: &String = &args[1];
     
     if path::Path::new(file_path).exists() {
         println!("File exists, reading '{}'", file_path);
@@ -53,7 +65,16 @@ fn main() {
             let magic_num: &[u8] = &bytes[0..4];
         
             if magic_num == ELF_MAGIC_NUMBER {
-                println!("Found ELF Magic Number!");
+                println!("Found ELF Magic Number...");
+                println!("Parsing File Header...");
+
+                // Build the File Header data structure
+                let file_header_map = build_fild_header(bytes);
+
+                for (key, value) in &file_header_map {
+                    println!("{}: {}", key, value);
+                }
+
             } else {
                 println!("[Error] Could not find magic number, is this an ELF executable?")
             }
@@ -65,3 +86,31 @@ fn main() {
 
     return;
 }
+
+
+fn build_fild_header(data: &Vec<u8>) -> HashMap<String, u8>{
+    let mut file_header: HashMap<String, u8> = HashMap::new();
+    
+    // Determine x86 or x64 architecture
+    // 0 : x86
+    // 1 : x64
+    let arch: u8 = (data[ELF_ARCH_OFFSET as usize] - 1).into();
+
+    file_header.insert("e_arch".to_string(), data[ELF_ARCH_OFFSET as usize]);
+    file_header.insert("e_endian".to_string(), data[ELF_ENDIAN_OFFSET as usize]);
+    file_header.insert("e_abi".to_string(), data[ELF_ABI_OFFSET as usize]);
+    file_header.insert("e_type".to_string(), data[ELF_TYPE_OFFSET as usize]);
+    file_header.insert("e_machine".to_string(), data[ELF_MACHINE_OFFSET as usize]);
+
+    file_header.insert("e_entry".to_string(), data[ELF_ENTRYPOINT_OFFSET as usize]);
+    file_header.insert("e_phoff".to_string(), data[ELF_PHOFF_OFFSET[arch as usize] as usize]);
+    file_header.insert("e_shoff".to_string(), data[ELF_SHOFF_OFFSET[arch as usize] as usize]);
+    file_header.insert("e_ehsize".to_string(), data[ELF_EHSIZE_OFFSET[arch as usize] as usize]);
+    file_header.insert("e_phentsize".to_string(), data[ELF_PHENTSIZE_OFFSET[arch as usize] as usize]);
+    file_header.insert("e_phnum".to_string(), data[ELF_PHNUM_OFFSET[arch as usize] as usize]);
+    file_header.insert("e_shentsize".to_string(), data[ELF_SHENTSIZE_OFFSET[arch as usize] as usize]);
+    file_header.insert("e_shnum".to_string(), data[ELF_SHNUM_OFFSET[arch as usize] as usize]);
+    file_header.insert("e_shstrndx".to_string(), data[ELF_SHSTRNDX_OFFSET[arch as usize] as usize]);
+
+    return file_header;
+}