pe(write): some debug! traces

It can be hard to debug why your writer is not working as intended, here
are some `debug!` traces to help in that endeavor.

src/pe/certificate_table.rs

@@ -134,6 +134,7 @@ impl<'a> AttributeCertificate<'a> {
         bytes: &'a [u8],
         current_offset: &mut usize,
     ) -> Result<AttributeCertificate<'a>, error::Error> {
+        debug!("reading certificate header at {current_offset}");
         // `current_offset` is moved sizeof(AttributeCertificateHeader) = 8 bytes further.
         let header: AttributeCertificateHeader = bytes.gread_with(current_offset, scroll::LE)?;
         let cert_size = usize::try_from(header.length.saturating_sub(CERTIFICATE_DATA_OFFSET))
@@ -143,6 +144,11 @@ impl<'a> AttributeCertificate<'a> {
                 )
             })?;
 
+        debug!(
+            "parsing certificate header {:#?}, predicted certificate size: {}",
+            header, cert_size
+        );
+
         if let Some(bytes) = bytes.get(*current_offset..(*current_offset + cert_size)) {
             let attr = Self {
                 length: header.length,
@@ -178,6 +184,13 @@ impl<'a> ctx::TryIntoCtx<scroll::Endian> for &AttributeCertificate<'a> {
         let maybe_certificate_padding = pad(self.certificate.len(), Some(16usize));
         bytes.gwrite(self.certificate, offset)?;
         if let Some(cert_padding) = maybe_certificate_padding {
+            debug!(
+                "Extending the buffer ({}) at offset {} with {} extra bytes for quadword alignment",
+                bytes.len(),
+                *offset,
+                cert_padding.len()
+            );
+
             bytes.gwrite(&cert_padding[..], offset)?;
         }
 

src/pe/header.rs

@@ -253,6 +253,7 @@ impl CoffHeader {
         let string_table_offset = self.pointer_to_symbol_table as usize
             + symbol::SymbolTable::size(self.number_of_symbol_table as usize);
         for i in 0..nsections {
+            debug!("parsing section at offset {offset}");
             let section =
                 section_table::SectionTable::parse(bytes, offset, string_table_offset as usize)?;
             debug!("({}) {:#?}", i, section);
@@ -342,6 +343,7 @@ impl ctx::TryIntoCtx<scroll::Endian> for Header {
         bytes.gwrite_with(self.dos_stub, offset, ctx)?;
         bytes.gwrite_with(self.signature, offset, scroll::LE)?;
         bytes.gwrite_with(self.coff_header, offset, ctx)?;
+        debug!("Non-optional header written, current offset: {}", offset);
         if let Some(opt_header) = self.optional_header {
             bytes.gwrite_with(opt_header, offset, ctx)?;
         }

src/pe/optional_header.rs

@@ -2,6 +2,7 @@ use crate::container;
 use crate::error;
 
 use crate::pe::data_directories;
+use crate::pe::debug;
 
 use scroll::{ctx, Endian, LE};
 use scroll::{Pread, Pwrite, SizeWith};
@@ -358,12 +359,16 @@ impl ctx::TryIntoCtx<scroll::Endian> for OptionalHeader {
         match self.standard_fields.magic {
             MAGIC_32 => {
                 bytes.gwrite_with::<StandardFields32>(self.standard_fields.into(), offset, ctx)?;
+                debug!("Wrote standard fields 32 bits (offset: {})", offset);
                 bytes.gwrite_with(WindowsFields32::try_from(self.windows_fields)?, offset, ctx)?;
+                debug!("Wrote windows fields 32 bits (offset: {})", offset);
                 bytes.gwrite_with(self.data_directories, offset, ctx)?;
             }
             MAGIC_64 => {
                 bytes.gwrite_with::<StandardFields64>(self.standard_fields.into(), offset, ctx)?;
+                debug!("Wrote standard fields 64 bits (offset: {})", offset);
                 bytes.gwrite_with(self.windows_fields, offset, ctx)?;
+                debug!("Wrote windows fields 64 bits (offset: {})", offset);
                 bytes.gwrite_with(self.data_directories, offset, ctx)?;
             }
             _ => panic!(),