PE import start (fixed header size -> sections work)

src/backend/container/pe/import.rs

@@ -1,33 +1,56 @@
-use crate::backend::ByteEncoder;
+use crate::backend::pe::data_dir::DataDir;
+
+use super::ByteEncoder;
 
 pub struct Import {
     pub name: String,
     pub names: Vec<String>,
 }
 
-pub fn encode(data: &mut ByteEncoder, imports: &[Import]) -> usize {
-    let mut names = 0;
-    for import in imports {
-        for name in &import.names {
-            data.extend(ImportLookupEntry::name().bytes());
-            names += 1;
+pub fn encode(data: &mut ByteEncoder, imports: &[Import]) -> DataDir {
+    let start = data.pos() as u32;
+    let idt = data.reserve_arr::<ImportDirTable>(imports.len());
+    // null entry to mark end
+    data.pad(size_of::<ImportDirTable>());
+    let end = data.pos() as u32;
+
+    for (i, import) in imports.iter().enumerate() {
+        // name
+        let name_rva = data.pos() as u32;
+        data.extend(import.name.as_bytes());
+        data.push(0);
+
+        // lookup table
+        data.align(size_of::<ImportLookupEntry>());
+        let lookup_start = data.pos();
+        let lookup = data.reserve_arr::<ImportLookupEntry>(import.names.len());
+        data.pad(size_of::<ImportLookupEntry>());
+        let lookup_end = data.pos();
+
+        for (i, name) in import.names.iter().enumerate() {
+            let rva = hint_name_entry(data, 0, name);
+            data[lookup][i] = ImportLookupEntry::name(rva);
         }
-        data.extend(ImportLookupEntry::NULL.bytes());
-    }
-    let table_addr = data.pos();
-    for import in imports {
-        let idt = ImportDirTable {
-            lookup_table_rva: todo!(),
+
+        // address table
+        data.align(size_of::<ImportLookupEntry>());
+        let addr_start = data.pos();
+        let len = lookup_end - lookup_start;
+        data.pad(len);
+        data.data.copy_within(lookup_start..lookup_end, addr_start);
+
+        // entry
+        data[idt][i] = ImportDirTable {
+            lookup_table_rva: lookup_start as u32,
             time_date_stamp: 0,
             forwarder_chain: 0,
-            name_rva: todo!(),
-            address_table_rva: todo!(),
+            name_rva,
+            address_table_rva: addr_start as u32,
         };
     }
-    for import in imports {
-        for name in &import.names {
-            hint_name_entry(data, 0, &name);
-        }
+    DataDir {
+        virt_addr_rva: start,
+        size: end - start,
     }
 }
 
@@ -40,16 +63,6 @@ pub struct ImportDirTable {
     pub address_table_rva: u32,
 }
 
-impl ImportDirTable {
-    pub const NULL: Self = Self {
-        lookup_table_rva: 0,
-        time_date_stamp: 0,
-        forwarder_chain: 0,
-        name_rva: 0,
-        address_table_rva: 0,
-    };
-}
-
 #[repr(C)]
 pub struct ImportLookupEntry(u64);
 
@@ -67,11 +80,11 @@ impl ImportLookupEntry {
     }
 }
 
-pub fn hint_name_entry(out: &mut Vec<u8>, hint: u16, name: &str) {
-    out.extend(hint.to_le_bytes());
-    out.extend(name.as_bytes());
-    out.push(0);
-    if out.len() % 2 == 1 {
-        out.push(0);
-    }
+pub fn hint_name_entry(data: &mut ByteEncoder, hint: u16, name: &str) -> u32 {
+    let pos = data.pos() as u32;
+    data.extend(hint.to_le_bytes());
+    data.extend(name.as_bytes());
+    data.push(0);
+    data.align(2);
+    pos
 }