skip headers

cmd/soroban-cli/Cargo.toml

@@ -113,6 +113,8 @@ home = "0.5.9"
 wasm-encoder = "0.202.0"
 rustc_version_runtime = "0.3.0"
 
+leb128 = "0.2.5"
+
 # For hyper-tls
 [target.'cfg(unix)'.dependencies]
 openssl = { version = "=0.10.55", features = ["vendored"] }

cmd/soroban-cli/src/commands/contract/build.rs

@@ -253,6 +253,9 @@ impl Cmd {
         let mut wasm = read_wasm_without_contractmeta(&contract_buf)?;
         custom_section.append_to(&mut wasm);
 
+        let backup_path = target_file_path.with_extension("back.wasm");
+        fs::copy(&target_file_path, backup_path).map_err(Error::CopyingWasmFile)?;
+
         let temp_file = format!("{}.{}.temp", target_file, rand::random::<u32>());
         let temp_file_path = file_path.join(temp_file);
 
@@ -296,14 +299,17 @@ fn read_wasm_without_contractmeta(contract_buf: &[u8]) -> Result<Vec<u8>, Error>
 
     println!("read_wasm_without_contractmeta =======================");
     for payload in WasmParser::new(0).parse_all(contract_buf) {
-        match payload.map_err(Error::ParsingWasm)? {
+        let payload = payload.map_err(Error::ParsingWasm)?;
+        match payload {
             Payload::CustomSection(s) => match s.name() {
                 "contractmetav0" => {
                     let range = s.range();
                     let data_offset = s.data_offset();
+                    let section_header_size = calc_section_header_size(&range);
                     println!("data_offset: {data_offset}, range: {:?}", range);
+                    assert!(range.start >= section_header_size);
                     if range.start > 0 {
-                        module.extend_from_slice(&contract_buf[0..range.start]);
+                        module.extend_from_slice(&contract_buf[0..(range.start - section_header_size)]);
                     }
                     if range.end < buf_len {
                         module.extend_from_slice(&contract_buf[range.end..buf_len]);
@@ -317,3 +323,12 @@ fn read_wasm_without_contractmeta(contract_buf: &[u8]) -> Result<Vec<u8>, Error>
     module.shrink_to_fit();
     Ok(module)
 }
+
+fn calc_section_header_size(range: &std::ops::Range<usize>) -> usize {
+    let len = range.end - range.start;
+    let mut buf = Vec::new();
+    let int_enc_size = leb128::write::unsigned(&mut buf, len as u64);
+    let int_enc_size = int_enc_size.expect("leb128 write");
+    let section_id_byte = 1;
+    int_enc_size + section_id_byte
+}