Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 847 insertions, 0 deletions

diff --git a/third_party/rust/object/src/write/pe.rs b/third_party/rust/object/src/write/pe.rs
new file mode 100644
index 0000000000..70da3a0937
--- /dev/null
+++ b/third_party/rust/object/src/write/pe.rs
@@ -0,0 +1,847 @@
+//! Helper for writing PE files.
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::mem;
+
+use crate::endian::{LittleEndian as LE, *};
+use crate::pe;
+use crate::write::util;
+use crate::write::{Error, Result, WritableBuffer};
+
+/// A helper for writing PE files.
+///
+/// Writing uses a two phase approach. The first phase reserves file ranges and virtual
+/// address ranges for everything in the order that they will be written.
+///
+/// The second phase writes everything out in order. Thus the caller must ensure writing
+/// is in the same order that file ranges were reserved.
+#[allow(missing_debug_implementations)]
+pub struct Writer<'a> {
+    is_64: bool,
+    section_alignment: u32,
+    file_alignment: u32,
+
+    buffer: &'a mut dyn WritableBuffer,
+    len: u32,
+    virtual_len: u32,
+    headers_len: u32,
+
+    code_address: u32,
+    data_address: u32,
+    code_len: u32,
+    data_len: u32,
+    bss_len: u32,
+
+    nt_headers_offset: u32,
+    data_directories: Vec<DataDirectory>,
+    section_header_num: u16,
+    sections: Vec<Section>,
+
+    symbol_offset: u32,
+    symbol_num: u32,
+
+    reloc_blocks: Vec<RelocBlock>,
+    relocs: Vec<U16<LE>>,
+    reloc_offset: u32,
+}
+
+impl<'a> Writer<'a> {
+    /// Create a new `Writer`.
+    pub fn new(
+        is_64: bool,
+        section_alignment: u32,
+        file_alignment: u32,
+        buffer: &'a mut dyn WritableBuffer,
+    ) -> Self {
+        Writer {
+            is_64,
+            section_alignment,
+            file_alignment,
+
+            buffer,
+            len: 0,
+            virtual_len: 0,
+            headers_len: 0,
+
+            code_address: 0,
+            data_address: 0,
+            code_len: 0,
+            data_len: 0,
+            bss_len: 0,
+
+            nt_headers_offset: 0,
+            data_directories: Vec::new(),
+            section_header_num: 0,
+            sections: Vec::new(),
+
+            symbol_offset: 0,
+            symbol_num: 0,
+
+            reloc_blocks: Vec::new(),
+            relocs: Vec::new(),
+            reloc_offset: 0,
+        }
+    }
+
+    /// Return the current virtual address size that has been reserved.
+    ///
+    /// This is only valid after section headers have been reserved.
+    pub fn virtual_len(&self) -> u32 {
+        self.virtual_len
+    }
+
+    /// Reserve a virtual address range with the given size.
+    ///
+    /// The reserved length will be increased to match the section alignment.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    pub fn reserve_virtual(&mut self, len: u32) -> u32 {
+        let offset = self.virtual_len;
+        self.virtual_len += len;
+        self.virtual_len = util::align_u32(self.virtual_len, self.section_alignment);
+        offset
+    }
+
+    /// Reserve up to the given virtual address.
+    ///
+    /// The reserved length will be increased to match the section alignment.
+    pub fn reserve_virtual_until(&mut self, address: u32) {
+        debug_assert!(self.virtual_len <= address);
+        self.virtual_len = util::align_u32(address, self.section_alignment);
+    }
+
+    /// Return the current file length that has been reserved.
+    pub fn reserved_len(&self) -> u32 {
+        self.len
+    }
+
+    /// Return the current file length that has been written.
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> usize {
+        self.buffer.len()
+    }
+
+    /// Reserve a file range with the given size and starting alignment.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    pub fn reserve(&mut self, len: u32, align_start: u32) -> u32 {
+        if len == 0 {
+            return self.len;
+        }
+        self.reserve_align(align_start);
+        let offset = self.len;
+        self.len += len;
+        offset
+    }
+
+    /// Reserve a file range with the given size and using the file alignment.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    pub fn reserve_file(&mut self, len: u32) -> u32 {
+        self.reserve(len, self.file_alignment)
+    }
+
+    /// Write data.
+    pub fn write(&mut self, data: &[u8]) {
+        self.buffer.write_bytes(data);
+    }
+
+    /// Reserve alignment padding bytes.
+    pub fn reserve_align(&mut self, align_start: u32) {
+        self.len = util::align_u32(self.len, align_start);
+    }
+
+    /// Write alignment padding bytes.
+    pub fn write_align(&mut self, align_start: u32) {
+        util::write_align(self.buffer, align_start as usize);
+    }
+
+    /// Write padding up to the next multiple of file alignment.
+    pub fn write_file_align(&mut self) {
+        self.write_align(self.file_alignment);
+    }
+
+    /// Reserve the file range up to the given file offset.
+    pub fn reserve_until(&mut self, offset: u32) {
+        debug_assert!(self.len <= offset);
+        self.len = offset;
+    }
+
+    /// Write padding up to the given file offset.
+    pub fn pad_until(&mut self, offset: u32) {
+        debug_assert!(self.buffer.len() <= offset as usize);
+        self.buffer.resize(offset as usize);
+    }
+
+    /// Reserve the range for the DOS header.
+    ///
+    /// This must be at the start of the file.
+    ///
+    /// When writing, you may use `write_custom_dos_header` or `write_empty_dos_header`.
+    pub fn reserve_dos_header(&mut self) {
+        debug_assert_eq!(self.len, 0);
+        self.reserve(mem::size_of::<pe::ImageDosHeader>() as u32, 1);
+    }
+
+    /// Write a custom DOS header.
+    ///
+    /// This must be at the start of the file.
+    pub fn write_custom_dos_header(&mut self, dos_header: &pe::ImageDosHeader) -> Result<()> {
+        debug_assert_eq!(self.buffer.len(), 0);
+
+        // Start writing.
+        self.buffer
+            .reserve(self.len as usize)
+            .map_err(|_| Error(String::from("Cannot allocate buffer")))?;
+
+        self.buffer.write(dos_header);
+        Ok(())
+    }
+
+    /// Write the DOS header for a file without a stub.
+    ///
+    /// This must be at the start of the file.
+    ///
+    /// Uses default values for all fields.
+    pub fn write_empty_dos_header(&mut self) -> Result<()> {
+        self.write_custom_dos_header(&pe::ImageDosHeader {
+            e_magic: U16::new(LE, pe::IMAGE_DOS_SIGNATURE),
+            e_cblp: U16::new(LE, 0),
+            e_cp: U16::new(LE, 0),
+            e_crlc: U16::new(LE, 0),
+            e_cparhdr: U16::new(LE, 0),
+            e_minalloc: U16::new(LE, 0),
+            e_maxalloc: U16::new(LE, 0),
+            e_ss: U16::new(LE, 0),
+            e_sp: U16::new(LE, 0),
+            e_csum: U16::new(LE, 0),
+            e_ip: U16::new(LE, 0),
+            e_cs: U16::new(LE, 0),
+            e_lfarlc: U16::new(LE, 0),
+            e_ovno: U16::new(LE, 0),
+            e_res: [U16::new(LE, 0); 4],
+            e_oemid: U16::new(LE, 0),
+            e_oeminfo: U16::new(LE, 0),
+            e_res2: [U16::new(LE, 0); 10],
+            e_lfanew: U32::new(LE, self.nt_headers_offset),
+        })
+    }
+
+    /// Reserve a fixed DOS header and stub.
+    ///
+    /// Use `reserve_dos_header` and `reserve` if you need a custom stub.
+    pub fn reserve_dos_header_and_stub(&mut self) {
+        self.reserve_dos_header();
+        self.reserve(64, 1);
+    }
+
+    /// Write a fixed DOS header and stub.
+    ///
+    /// Use `write_custom_dos_header` and `write` if you need a custom stub.
+    pub fn write_dos_header_and_stub(&mut self) -> Result<()> {
+        self.write_custom_dos_header(&pe::ImageDosHeader {
+            e_magic: U16::new(LE, pe::IMAGE_DOS_SIGNATURE),
+            e_cblp: U16::new(LE, 0x90),
+            e_cp: U16::new(LE, 3),
+            e_crlc: U16::new(LE, 0),
+            e_cparhdr: U16::new(LE, 4),
+            e_minalloc: U16::new(LE, 0),
+            e_maxalloc: U16::new(LE, 0xffff),
+            e_ss: U16::new(LE, 0),
+            e_sp: U16::new(LE, 0xb8),
+            e_csum: U16::new(LE, 0),
+            e_ip: U16::new(LE, 0),
+            e_cs: U16::new(LE, 0),
+            e_lfarlc: U16::new(LE, 0x40),
+            e_ovno: U16::new(LE, 0),
+            e_res: [U16::new(LE, 0); 4],
+            e_oemid: U16::new(LE, 0),
+            e_oeminfo: U16::new(LE, 0),
+            e_res2: [U16::new(LE, 0); 10],
+            e_lfanew: U32::new(LE, self.nt_headers_offset),
+        })?;
+
+        #[rustfmt::skip]
+        self.buffer.write_bytes(&[
+            0x0e, 0x1f, 0xba, 0x0e, 0x00, 0xb4, 0x09, 0xcd,
+            0x21, 0xb8, 0x01, 0x4c, 0xcd, 0x21, 0x54, 0x68,
+            0x69, 0x73, 0x20, 0x70, 0x72, 0x6f, 0x67, 0x72,
+            0x61, 0x6d, 0x20, 0x63, 0x61, 0x6e, 0x6e, 0x6f,
+            0x74, 0x20, 0x62, 0x65, 0x20, 0x72, 0x75, 0x6e,
+            0x20, 0x69, 0x6e, 0x20, 0x44, 0x4f, 0x53, 0x20,
+            0x6d, 0x6f, 0x64, 0x65, 0x2e, 0x0d, 0x0d, 0x0a,
+            0x24, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        ]);
+
+        Ok(())
+    }
+
+    fn nt_headers_size(&self) -> u32 {
+        if self.is_64 {
+            mem::size_of::<pe::ImageNtHeaders64>() as u32
+        } else {
+            mem::size_of::<pe::ImageNtHeaders32>() as u32
+        }
+    }
+
+    fn optional_header_size(&self) -> u32 {
+        let size = if self.is_64 {
+            mem::size_of::<pe::ImageOptionalHeader64>() as u32
+        } else {
+            mem::size_of::<pe::ImageOptionalHeader32>() as u32
+        };
+        size + self.data_directories.len() as u32 * mem::size_of::<pe::ImageDataDirectory>() as u32
+    }
+
+    /// Return the offset of the NT headers, if reserved.
+    pub fn nt_headers_offset(&self) -> u32 {
+        self.nt_headers_offset
+    }
+
+    /// Reserve the range for the NT headers.
+    pub fn reserve_nt_headers(&mut self, data_directory_num: usize) {
+        debug_assert_eq!(self.nt_headers_offset, 0);
+        self.nt_headers_offset = self.reserve(self.nt_headers_size(), 8);
+        self.data_directories = vec![DataDirectory::default(); data_directory_num];
+        self.reserve(
+            data_directory_num as u32 * mem::size_of::<pe::ImageDataDirectory>() as u32,
+            1,
+        );
+    }
+
+    /// Set the virtual address and size of a data directory.
+    pub fn set_data_directory(&mut self, index: usize, virtual_address: u32, size: u32) {
+        self.data_directories[index] = DataDirectory {
+            virtual_address,
+            size,
+        }
+    }
+
+    /// Write the NT headers.
+    pub fn write_nt_headers(&mut self, nt_headers: NtHeaders) {
+        self.pad_until(self.nt_headers_offset);
+        self.buffer.write(&U32::new(LE, pe::IMAGE_NT_SIGNATURE));
+        let file_header = pe::ImageFileHeader {
+            machine: U16::new(LE, nt_headers.machine),
+            number_of_sections: U16::new(LE, self.section_header_num),
+            time_date_stamp: U32::new(LE, nt_headers.time_date_stamp),
+            pointer_to_symbol_table: U32::new(LE, self.symbol_offset),
+            number_of_symbols: U32::new(LE, self.symbol_num),
+            size_of_optional_header: U16::new(LE, self.optional_header_size() as u16),
+            characteristics: U16::new(LE, nt_headers.characteristics),
+        };
+        self.buffer.write(&file_header);
+        if self.is_64 {
+            let optional_header = pe::ImageOptionalHeader64 {
+                magic: U16::new(LE, pe::IMAGE_NT_OPTIONAL_HDR64_MAGIC),
+                major_linker_version: nt_headers.major_linker_version,
+                minor_linker_version: nt_headers.minor_linker_version,
+                size_of_code: U32::new(LE, self.code_len),
+                size_of_initialized_data: U32::new(LE, self.data_len),
+                size_of_uninitialized_data: U32::new(LE, self.bss_len),
+                address_of_entry_point: U32::new(LE, nt_headers.address_of_entry_point),
+                base_of_code: U32::new(LE, self.code_address),
+                image_base: U64::new(LE, nt_headers.image_base),
+                section_alignment: U32::new(LE, self.section_alignment),
+                file_alignment: U32::new(LE, self.file_alignment),
+                major_operating_system_version: U16::new(
+                    LE,
+                    nt_headers.major_operating_system_version,
+                ),
+                minor_operating_system_version: U16::new(
+                    LE,
+                    nt_headers.minor_operating_system_version,
+                ),
+                major_image_version: U16::new(LE, nt_headers.major_image_version),
+                minor_image_version: U16::new(LE, nt_headers.minor_image_version),
+                major_subsystem_version: U16::new(LE, nt_headers.major_subsystem_version),
+                minor_subsystem_version: U16::new(LE, nt_headers.minor_subsystem_version),
+                win32_version_value: U32::new(LE, 0),
+                size_of_image: U32::new(LE, self.virtual_len),
+                size_of_headers: U32::new(LE, self.headers_len),
+                check_sum: U32::new(LE, 0),
+                subsystem: U16::new(LE, nt_headers.subsystem),
+                dll_characteristics: U16::new(LE, nt_headers.dll_characteristics),
+                size_of_stack_reserve: U64::new(LE, nt_headers.size_of_stack_reserve),
+                size_of_stack_commit: U64::new(LE, nt_headers.size_of_stack_commit),
+                size_of_heap_reserve: U64::new(LE, nt_headers.size_of_heap_reserve),
+                size_of_heap_commit: U64::new(LE, nt_headers.size_of_heap_commit),
+                loader_flags: U32::new(LE, 0),
+                number_of_rva_and_sizes: U32::new(LE, self.data_directories.len() as u32),
+            };
+            self.buffer.write(&optional_header);
+        } else {
+            let optional_header = pe::ImageOptionalHeader32 {
+                magic: U16::new(LE, pe::IMAGE_NT_OPTIONAL_HDR32_MAGIC),
+                major_linker_version: nt_headers.major_linker_version,
+                minor_linker_version: nt_headers.minor_linker_version,
+                size_of_code: U32::new(LE, self.code_len),
+                size_of_initialized_data: U32::new(LE, self.data_len),
+                size_of_uninitialized_data: U32::new(LE, self.bss_len),
+                address_of_entry_point: U32::new(LE, nt_headers.address_of_entry_point),
+                base_of_code: U32::new(LE, self.code_address),
+                base_of_data: U32::new(LE, self.data_address),
+                image_base: U32::new(LE, nt_headers.image_base as u32),
+                section_alignment: U32::new(LE, self.section_alignment),
+                file_alignment: U32::new(LE, self.file_alignment),
+                major_operating_system_version: U16::new(
+                    LE,
+                    nt_headers.major_operating_system_version,
+                ),
+                minor_operating_system_version: U16::new(
+                    LE,
+                    nt_headers.minor_operating_system_version,
+                ),
+                major_image_version: U16::new(LE, nt_headers.major_image_version),
+                minor_image_version: U16::new(LE, nt_headers.minor_image_version),
+                major_subsystem_version: U16::new(LE, nt_headers.major_subsystem_version),
+                minor_subsystem_version: U16::new(LE, nt_headers.minor_subsystem_version),
+                win32_version_value: U32::new(LE, 0),
+                size_of_image: U32::new(LE, self.virtual_len),
+                size_of_headers: U32::new(LE, self.headers_len),
+                check_sum: U32::new(LE, 0),
+                subsystem: U16::new(LE, nt_headers.subsystem),
+                dll_characteristics: U16::new(LE, nt_headers.dll_characteristics),
+                size_of_stack_reserve: U32::new(LE, nt_headers.size_of_stack_reserve as u32),
+                size_of_stack_commit: U32::new(LE, nt_headers.size_of_stack_commit as u32),
+                size_of_heap_reserve: U32::new(LE, nt_headers.size_of_heap_reserve as u32),
+                size_of_heap_commit: U32::new(LE, nt_headers.size_of_heap_commit as u32),
+                loader_flags: U32::new(LE, 0),
+                number_of_rva_and_sizes: U32::new(LE, self.data_directories.len() as u32),
+            };
+            self.buffer.write(&optional_header);
+        }
+
+        for dir in &self.data_directories {
+            self.buffer.write(&pe::ImageDataDirectory {
+                virtual_address: U32::new(LE, dir.virtual_address),
+                size: U32::new(LE, dir.size),
+            })
+        }
+    }
+
+    /// Reserve the section headers.
+    ///
+    /// The number of reserved section headers must be the same as the number of sections that
+    /// are later reserved.
+    // TODO: change this to a maximum number of sections?
+    pub fn reserve_section_headers(&mut self, section_header_num: u16) {
+        debug_assert_eq!(self.section_header_num, 0);
+        self.section_header_num = section_header_num;
+        self.reserve(
+            u32::from(section_header_num) * mem::size_of::<pe::ImageSectionHeader>() as u32,
+            1,
+        );
+        // Padding before sections must be included in headers_len.
+        self.reserve_align(self.file_alignment);
+        self.headers_len = self.len;
+        self.reserve_virtual(self.len);
+    }
+
+    /// Write the section headers.
+    ///
+    /// This uses information that was recorded when the sections were reserved.
+    pub fn write_section_headers(&mut self) {
+        debug_assert_eq!(self.section_header_num as usize, self.sections.len());
+        for section in &self.sections {
+            let section_header = pe::ImageSectionHeader {
+                name: section.name,
+                virtual_size: U32::new(LE, section.range.virtual_size),
+                virtual_address: U32::new(LE, section.range.virtual_address),
+                size_of_raw_data: U32::new(LE, section.range.file_size),
+                pointer_to_raw_data: U32::new(LE, section.range.file_offset),
+                pointer_to_relocations: U32::new(LE, 0),
+                pointer_to_linenumbers: U32::new(LE, 0),
+                number_of_relocations: U16::new(LE, 0),
+                number_of_linenumbers: U16::new(LE, 0),
+                characteristics: U32::new(LE, section.characteristics),
+            };
+            self.buffer.write(&section_header);
+        }
+    }
+
+    /// Reserve a section.
+    ///
+    /// Returns the file range and virtual address range that are reserved
+    /// for the section.
+    pub fn reserve_section(
+        &mut self,
+        name: [u8; 8],
+        characteristics: u32,
+        virtual_size: u32,
+        data_size: u32,
+    ) -> SectionRange {
+        let virtual_address = self.reserve_virtual(virtual_size);
+
+        // Padding after section must be included in section file size.
+        let file_size = util::align_u32(data_size, self.file_alignment);
+        let file_offset = if file_size != 0 {
+            self.reserve(file_size, self.file_alignment)
+        } else {
+            0
+        };
+
+        // Sizes in optional header use the virtual size with the file alignment.
+        let aligned_virtual_size = util::align_u32(virtual_size, self.file_alignment);
+        if characteristics & pe::IMAGE_SCN_CNT_CODE != 0 {
+            if self.code_address == 0 {
+                self.code_address = virtual_address;
+            }
+            self.code_len += aligned_virtual_size;
+        } else if characteristics & pe::IMAGE_SCN_CNT_INITIALIZED_DATA != 0 {
+            if self.data_address == 0 {
+                self.data_address = virtual_address;
+            }
+            self.data_len += aligned_virtual_size;
+        } else if characteristics & pe::IMAGE_SCN_CNT_UNINITIALIZED_DATA != 0 {
+            if self.data_address == 0 {
+                self.data_address = virtual_address;
+            }
+            self.bss_len += aligned_virtual_size;
+        }
+
+        let range = SectionRange {
+            virtual_address,
+            virtual_size,
+            file_offset,
+            file_size,
+        };
+        self.sections.push(Section {
+            name,
+            characteristics,
+            range,
+        });
+        range
+    }
+
+    /// Write the data for a section.
+    pub fn write_section(&mut self, offset: u32, data: &[u8]) {
+        if data.is_empty() {
+            return;
+        }
+        self.pad_until(offset);
+        self.write(data);
+        self.write_align(self.file_alignment);
+    }
+
+    /// Reserve a `.text` section.
+    ///
+    /// Contains executable code.
+    pub fn reserve_text_section(&mut self, size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".text\0\0\0",
+            pe::IMAGE_SCN_CNT_CODE | pe::IMAGE_SCN_MEM_EXECUTE | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        )
+    }
+
+    /// Reserve a `.data` section.
+    ///
+    /// Contains initialized data.
+    ///
+    /// May also contain uninitialized data if `virtual_size` is greater than `data_size`.
+    pub fn reserve_data_section(&mut self, virtual_size: u32, data_size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".data\0\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ | pe::IMAGE_SCN_MEM_WRITE,
+            virtual_size,
+            data_size,
+        )
+    }
+
+    /// Reserve a `.rdata` section.
+    ///
+    /// Contains read-only initialized data.
+    pub fn reserve_rdata_section(&mut self, size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".rdata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        )
+    }
+
+    /// Reserve a `.bss` section.
+    ///
+    /// Contains uninitialized data.
+    pub fn reserve_bss_section(&mut self, size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".bss\0\0\0\0",
+            pe::IMAGE_SCN_CNT_UNINITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ | pe::IMAGE_SCN_MEM_WRITE,
+            size,
+            0,
+        )
+    }
+
+    /// Reserve an `.idata` section.
+    ///
+    /// Contains import tables. Note that it is permissible to store import tables in a different
+    /// section.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_IMPORT` data directory.
+    pub fn reserve_idata_section(&mut self, size: u32) -> SectionRange {
+        let range = self.reserve_section(
+            *b".idata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ | pe::IMAGE_SCN_MEM_WRITE,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_IMPORT];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        range
+    }
+
+    /// Reserve an `.edata` section.
+    ///
+    /// Contains export tables.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_EXPORT` data directory.
+    pub fn reserve_edata_section(&mut self, size: u32) -> SectionRange {
+        let range = self.reserve_section(
+            *b".edata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_EXPORT];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        range
+    }
+
+    /// Reserve a `.pdata` section.
+    ///
+    /// Contains exception information.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_EXCEPTION` data directory.
+    pub fn reserve_pdata_section(&mut self, size: u32) -> SectionRange {
+        let range = self.reserve_section(
+            *b".pdata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_EXCEPTION];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        range
+    }
+
+    /// Reserve a `.xdata` section.
+    ///
+    /// Contains exception information.
+    pub fn reserve_xdata_section(&mut self, size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".xdata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        )
+    }
+
+    /// Reserve a `.rsrc` section.
+    ///
+    /// Contains the resource directory.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_RESOURCE` data directory.
+    pub fn reserve_rsrc_section(&mut self, size: u32) -> SectionRange {
+        let range = self.reserve_section(
+            *b".rsrc\0\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_RESOURCE];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        range
+    }
+
+    /// Add a base relocation.
+    ///
+    /// `typ` must be one of the `IMAGE_REL_BASED_*` constants.
+    pub fn add_reloc(&mut self, mut virtual_address: u32, typ: u16) {
+        let reloc = U16::new(LE, typ << 12 | (virtual_address & 0xfff) as u16);
+        virtual_address &= !0xfff;
+        if let Some(block) = self.reloc_blocks.last_mut() {
+            if block.virtual_address == virtual_address {
+                self.relocs.push(reloc);
+                block.count += 1;
+                return;
+            }
+            // Blocks must have an even number of relocations.
+            if block.count & 1 != 0 {
+                self.relocs.push(U16::new(LE, 0));
+                block.count += 1;
+            }
+            debug_assert!(block.virtual_address < virtual_address);
+        }
+        self.relocs.push(reloc);
+        self.reloc_blocks.push(RelocBlock {
+            virtual_address,
+            count: 1,
+        });
+    }
+
+    /// Return true if a base relocation has been added.
+    pub fn has_relocs(&mut self) -> bool {
+        !self.relocs.is_empty()
+    }
+
+    /// Reserve a `.reloc` section.
+    ///
+    /// This contains the base relocations that were added with `add_reloc`.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_BASERELOC` data directory.
+    pub fn reserve_reloc_section(&mut self) -> SectionRange {
+        if let Some(block) = self.reloc_blocks.last_mut() {
+            // Blocks must have an even number of relocations.
+            if block.count & 1 != 0 {
+                self.relocs.push(U16::new(LE, 0));
+                block.count += 1;
+            }
+        }
+        let size = self.reloc_blocks.iter().map(RelocBlock::size).sum();
+        let range = self.reserve_section(
+            *b".reloc\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA
+                | pe::IMAGE_SCN_MEM_READ
+                | pe::IMAGE_SCN_MEM_DISCARDABLE,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_BASERELOC];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        self.reloc_offset = range.file_offset;
+        range
+    }
+
+    /// Write a `.reloc` section.
+    ///
+    /// This contains the base relocations that were added with `add_reloc`.
+    pub fn write_reloc_section(&mut self) {
+        if self.reloc_offset == 0 {
+            return;
+        }
+        self.pad_until(self.reloc_offset);
+
+        let mut total = 0;
+        for block in &self.reloc_blocks {
+            self.buffer.write(&pe::ImageBaseRelocation {
+                virtual_address: U32::new(LE, block.virtual_address),
+                size_of_block: U32::new(LE, block.size()),
+            });
+            self.buffer
+                .write_slice(&self.relocs[total..][..block.count as usize]);
+            total += block.count as usize;
+        }
+        debug_assert_eq!(total, self.relocs.len());
+
+        self.write_align(self.file_alignment);
+    }
+
+    /// Reserve the certificate table.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_SECURITY` data directory.
+    // TODO: reserve individual certificates
+    pub fn reserve_certificate_table(&mut self, size: u32) {
+        let size = util::align_u32(size, 8);
+        let offset = self.reserve(size, 8);
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_SECURITY];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: offset,
+            size,
+        };
+    }
+
+    /// Write the certificate table.
+    // TODO: write individual certificates
+    pub fn write_certificate_table(&mut self, data: &[u8]) {
+        let dir = self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_SECURITY];
+        self.pad_until(dir.virtual_address);
+        self.write(data);
+        self.pad_until(dir.virtual_address + dir.size);
+    }
+}
+
+/// Information required for writing [`pe::ImageNtHeaders32`] or [`pe::ImageNtHeaders64`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct NtHeaders {
+    // ImageFileHeader
+    pub machine: u16,
+    pub time_date_stamp: u32,
+    pub characteristics: u16,
+    // ImageOptionalHeader
+    pub major_linker_version: u8,
+    pub minor_linker_version: u8,
+    pub address_of_entry_point: u32,
+    pub image_base: u64,
+    pub major_operating_system_version: u16,
+    pub minor_operating_system_version: u16,
+    pub major_image_version: u16,
+    pub minor_image_version: u16,
+    pub major_subsystem_version: u16,
+    pub minor_subsystem_version: u16,
+    pub subsystem: u16,
+    pub dll_characteristics: u16,
+    pub size_of_stack_reserve: u64,
+    pub size_of_stack_commit: u64,
+    pub size_of_heap_reserve: u64,
+    pub size_of_heap_commit: u64,
+}
+
+#[derive(Default, Clone, Copy)]
+struct DataDirectory {
+    virtual_address: u32,
+    size: u32,
+}
+
+/// Information required for writing [`pe::ImageSectionHeader`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct Section {
+    pub name: [u8; pe::IMAGE_SIZEOF_SHORT_NAME],
+    pub characteristics: u32,
+    pub range: SectionRange,
+}
+
+/// The file range and virtual address range for a section.
+#[allow(missing_docs)]
+#[derive(Debug, Default, Clone, Copy)]
+pub struct SectionRange {
+    pub virtual_address: u32,
+    pub virtual_size: u32,
+    pub file_offset: u32,
+    pub file_size: u32,
+}
+
+struct RelocBlock {
+    virtual_address: u32,
+    count: u32,
+}
+
+impl RelocBlock {
+    fn size(&self) -> u32 {
+        mem::size_of::<pe::ImageBaseRelocation>() as u32 + self.count * mem::size_of::<u16>() as u32
+    }
+}