first basic segment/section out

src/common/section.rs

@@ -14,7 +14,7 @@ pub struct SectionInfo<'data> {
 
 pub enum Section<'data> {
     Text(SectionInfo<'data>),
-    Data(SectionInfo<'data>),
+    Data(SectionInfo<'data>, bool), // readonly bool
     Bss(SectionInfo<'data>),
 }
 
@@ -22,7 +22,7 @@ impl Section<'_> {
     pub fn size(&self) -> Result<u64, Error> {
         match self {
             Section::Text(s) => Ok(s.size),
-            Section::Data(s) => Ok(s.size),
+            Section::Data(s, _) => Ok(s.size),
             Section::Bss(s) => Ok(s.size),
         }
     }
@@ -34,8 +34,10 @@ impl<'data> TryFrom<(&str, SectionInfo<'data>)> for Section<'data> {
     fn try_from(value: (&str, SectionInfo<'data>)) -> Result<Self, Self::Error> {
         if value.0.starts_with(".text") {
             Ok(Section::Text(value.1))
-        } else if value.0.starts_with(".rodata") || value.0.starts_with(".data") {
-            Ok(Section::Data(value.1))
+        } else if value.0.starts_with(".rodata") {
+            Ok(Section::Data(value.1, true))
+        } else if value.0.starts_with(".data") {
+            Ok(Section::Data(value.1, false))
         } else if value.0.starts_with(".bss") {
             Ok(Section::Bss(value.1))
         } else {
@@ -60,7 +62,8 @@ impl Display for Section<'_> {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
             Section::Text(s) => writeln!(f, "TEXT {}", s),
-            Section::Data(s) => writeln!(f, "DATA {}", s),
+            Section::Data(s, false) => writeln!(f, "DATA {}", s),
+            Section::Data(s, true) => writeln!(f, "RO-DATA {}", s),
             Section::Bss(s) => writeln!(f, "BSS {}", s),
         }
     }

src/common/storage.rs

@@ -21,7 +21,7 @@ impl Storage {
     }
 
     pub fn destination(&self) -> Result<PathBuf, Error> {
-        let mut dest = canonicalize(&self.origin).map_err(|e| Error::from(e))?;
+        let mut dest = canonicalize(&self.origin)?;
         if !dest.pop() {
             let err = std::io::Error::new(ErrorKind::Other, "Destination path invalid");
             Err(Error::IOError(Box::new(err)))

src/formats/elf.rs

@@ -4,6 +4,7 @@ use crate::linker::Linker;
 
 mod object;
 mod output;
+mod segment;
 
 use elf_utilities::file::ELF64;
 pub use object::*;
@@ -17,7 +18,7 @@ impl Linker<'_> {
 }
 
 impl<'data> Lazy<&'data str, ELF64> for Symbol<'data> {
-    fn value(&self, src: &ELF64) -> Result<&'data str, Error> {
+    fn value(&self, _src: &ELF64) -> Result<&'data str, Error> {
         Err(Error::InvalidSectionData) // TODO
     }
 

src/formats/elf/output.rs

@@ -1,27 +1,27 @@
-use std::path::PathBuf;
+use std::{fs::File, io::BufWriter, io::Write, mem::size_of, path::PathBuf};
 
 use elf_utilities::{
-    file::{ELF64Dumper, ELF64},
-    section::Section64,
-    segment::{Segment64, Type},
+    file::ELF64,
+    header::Ehdr64,
+    section::{build_string_table, Contents64, Section64, Shdr64},
+    segment::{Phdr64, PF_R, PF_W, PF_X},
 };
 
 use crate::{
-    common::{Output, Section, SectionInfo},
+    common::{Output, Section},
     error::Error,
 };
 
+use super::segment::*;
 use super::ElfObject;
 
 pub struct ElfOutput<'data> {
     destination: PathBuf,
-    dump: ELF64Dumper,
-    text: Vec<SectionInfo<'data>>,
-    data: Vec<SectionInfo<'data>>,
-    bss: Vec<SectionInfo<'data>>,
+    file: ELF64,
+    segment_data: SegmentData<'data>,
 }
 
-impl ElfOutput<'_> {
+impl<'data> ElfOutput<'data> {
     pub fn new(destination: PathBuf) -> Self {
         use elf_utilities::header::{Class, Data, Machine, Type, Version, OSABI};
 
@@ -36,55 +36,119 @@ impl ElfOutput<'_> {
 
         Self {
             destination,
-            dump: ELF64Dumper::new(elf),
-            text: Vec::new(),
-            data: Vec::new(),
-            bss: Vec::new(),
+            file: elf,
+            segment_data: SegmentData::new(),
         }
     }
 
     pub fn from_object(object: &ElfObject, destination: PathBuf) -> Self {
-        use elf_utilities::header::Type;
-
         let other = object.elf();
 
-        let mut elf = ELF64::default();
-        elf.ehdr = other.ehdr.clone();
-        elf.ehdr.set_elf_type(Type::Exec);
-
         Self {
             destination,
-            dump: ELF64Dumper::new(elf),
-            text: Vec::new(),
-            data: Vec::new(),
-            bss: Vec::new(),
+            file: elf_bin_from_object(other),
+            segment_data: SegmentData::new(),
         }
     }
 
-    fn populate_section_data(&mut self) -> Result<u64, Error> {
-        use elf_utilities::section::{Contents64, Shdr64, Type};
+    fn populate_sections(&mut self) -> Result<u64, Error> {
+        let mut names = Vec::new();
+        let mut names_len = 0usize;
+        let mut result = 0u64;
 
+        for (name, sections) in self.segment_data.iter_mut() {
             let mut data = Vec::new();
 
-        for t in self.text.iter_mut() {
+            for t in sections.iter_mut() {
                 if let Some(iter) = &mut t.data {
                     data.extend(iter.as_mut());
                 }
             }
 
-        let mut header = Shdr64::default();
-        header.set_type(Type::ProgBits);
-        header.sh_entsize = data.len() as u64;
+            if data.is_empty() {
+                continue;
+            }
 
-        let sec64 = Section64 {
-            name: ".text".into(),
-            header,
+            result += data.len() as u64;
+            names_len += name.len();
+            names.push(name);
+            let section = Section64 {
+                name: name.into(),
+                header: make_section_header(&name, names_len, data.len()),
                 contents: Contents64::Raw(data),
             };
+            self.file.add_section(section);
+        }
 
-        self.dump.file.add_section(sec64);
+        let name = ".shstrtab";
+        names_len += name.len();
+        names.push(name);
+        let string_table = build_string_table(names, true);
+        result += string_table.len() as u64;
+        let section = Section64 {
+            name: name.into(),
+            header: make_section_header(&name, names_len, string_table.len()),
+            contents: Contents64::Raw(string_table),
+        };
+        self.file.add_section(section);
 
-        Ok(0)
+        Ok(result)
+    }
+
+    fn populate_segment(&mut self, offset: &mut u64, size: u64, which: SegmentType) -> u64 {
+        use elf_utilities::segment::{Segment64, Type};
+
+        if size == 0 {
+            return 0;
+        }
+
+        let mut segment = Segment64 {
+            header: Phdr64::default(),
+        };
+        segment.header.set_type(Type::Load);
+        segment.header.p_filesz = size;
+        segment.header.p_memsz = size;
+        segment.header.p_offset = *offset;
+
+        match which {
+            SegmentType::Text => segment.header.p_flags = PF_R | PF_X,
+            SegmentType::Data => segment.header.p_flags = PF_R | PF_W,
+            SegmentType::Bss => {
+                segment.header.p_flags = PF_R;
+                segment.header.p_memsz = 0;
+            }
+        }
+
+        self.file.segments.push(segment);
+        self.file.ehdr.e_phnum += 1;
+        self.file.ehdr.e_phentsize = size_of::<Phdr64>() as u16;
+
+        *offset += size;
+
+        size
+    }
+
+    fn populate_segments(&mut self) -> Result<u64, Error> {
+        let mut offset = 0u64;
+        let mut result = 0u64;
+        // program header/segments
+        // contains .text + .rodata as one segment
+        result += self.populate_segment(
+            &mut offset,
+            self.segment_data.program_size(),
+            SegmentType::Text,
+        );
+        // contains .data as one segment
+        result += self.populate_segment(
+            &mut offset,
+            self.segment_data.data_size(),
+            SegmentType::Data,
+        );
+        // contains .bss as one segment
+        result +=
+            self.populate_segment(&mut offset, self.segment_data.bss_size(), SegmentType::Bss);
+
+        Ok(result)
     }
 }
 
@@ -94,24 +158,28 @@ impl<'data> Output<'data> for ElfOutput<'data> {
     }
 
     fn append_section(&mut self, section: Section<'data>) -> Result<(), Error> {
-        match section {
-            Section::Text(si) => self.text.push(si),
-            Section::Data(si) => self.data.push(si),
-            Section::Bss(si) => self.bss.push(si),
-        }
-
-        Ok(())
+        self.segment_data.append_section(section)
     }
 
     fn finalize(mut self) -> Result<PathBuf, Error> {
         use std::io::Error as IOError;
         use std::io::ErrorKind;
 
-        self.populate_section_data()?;
-        let mut segment = Segment64::default();
-        segment.header.set_type(Type::Load);
-        self.dump.file.segments.push(segment);
-        self.dump.file.finalize();
+        const EHS: u64 = size_of::<Ehdr64>() as u64;
+        const PHS: u64 = size_of::<Phdr64>() as u64;
+        const SHS: u16 = size_of::<Shdr64>() as u16;
+
+        let segment_data_size = self.populate_sections()?;
+        self.populate_segments()?;
+
+        self.file.ehdr.e_phentsize = PHS as u16;
+        self.file.ehdr.e_shentsize = SHS;
+        self.file.ehdr.e_phoff = EHS; // TODO: align
+        self.file.ehdr.e_shoff = self.file.ehdr.e_phoff
+            + u64::from(self.file.ehdr.e_phnum * self.file.ehdr.e_phentsize)
+            + segment_data_size;
+        self.file.ehdr.e_shnum = self.file.sections.len() as u16;
+        self.file.ehdr.e_entry = 0x100; // TODO
 
         let str_path = self.destination.to_str().ok_or_else(|| {
             let ioe = IOError::new(ErrorKind::Other, "Path expansion fail");
@@ -119,10 +187,80 @@ impl<'data> Output<'data> for ElfOutput<'data> {
             Error::IOError(boxed)
         })?;
 
-        self.dump
-            .generate_elf_file(str_path, 0o755)
-            .map_err(|e| Error::IOError(e))?;
+        let mut writer = file_writer(str_path, 0o755)?;
+        let mut offset = 0;
+
+        offset += writer.write(&self.file.ehdr.to_le_bytes())?;
+
+        // write program header table
+        for seg in self.file.segments.iter_mut() {
+            seg.header.p_offset = offset as u64;
+            offset += writer.write(&seg.header.to_le_bytes())?;
+        }
+
+        // write section/segment data
+        for sec in self.file.sections.iter_mut() {
+            sec.header.sh_offset = offset as u64;
+            offset += writer.write(&sec.to_le_bytes())?;
+        }
+
+        // write section header table
+        for sec in self.file.sections.iter() {
+            eprintln!("NAme index: {}", sec.header.sh_name);
+            offset += writer.write(&sec.header.to_le_bytes())?;
+        }
+        writer.flush()?;
 
         Ok(self.destination)
     }
 }
+
+fn file_writer(output_filename: &str, permission: u32) -> Result<BufWriter<File>, Error> {
+    use std::os::unix::fs::OpenOptionsExt;
+
+    let file = std::fs::OpenOptions::new()
+        .create(true)
+        .read(true)
+        .write(true)
+        .mode(permission)
+        .open(output_filename)?;
+
+    Ok(BufWriter::new(file))
+}
+
+// init new ELF64 from an object file meant as executable output
+fn elf_bin_from_object(other: &ELF64) -> ELF64 {
+    use elf_utilities::header::Type;
+
+    let mut elf = ELF64::default();
+    elf.ehdr.set_elf_type(Type::Exec);
+    elf.ehdr.e_ehsize = other.ehdr.e_ehsize;
+    elf.ehdr.e_version = other.ehdr.e_version;
+    elf.ehdr.e_ident = other.ehdr.e_ident;
+    elf.ehdr.e_machine = other.ehdr.e_machine;
+
+    elf
+}
+
+fn make_section_header(name: &str, names_len: usize, size: usize) -> Shdr64 {
+    use elf_utilities::section::Type;
+
+    let mut h = Shdr64::default();
+    match name {
+        ".shstrtab" => h.set_type(Type::StrTab),
+        ".bss" => h.set_type(Type::NoBits),
+        _ => h.set_type(Type::ProgBits),
+    }
+
+    // section index used for name and section indexing (currently same)
+    let idx = 1 + (names_len as u32); // add 0 at start
+                                        // name index
+    h.sh_name = idx;
+    // link index
+    h.sh_link = 0; //idx;
+    h.sh_size = size as u64;
+    // TODO
+    // h.sh_offset = offset;
+
+    h
+}

src/formats/elf/segment.rs

@@ -0,0 +1,83 @@
+use crate::common::Section;
+use crate::common::SectionInfo;
+use crate::error::Error;
+
+const SI_TEXT: usize = 0;
+const SI_RODATA: usize = 1;
+const SI_DATA: usize = 2;
+const SI_BSS: usize = 3;
+
+pub enum SegmentType {
+    Text = SI_TEXT as isize,
+    Data = SI_DATA as isize,
+    Bss = SI_BSS as isize,
+}
+
+const SEGMENT_NAMES: [&str; 4] = [".text", ".rodata", ".data", ".bss"];
+
+pub struct SegmentData<'data>([Vec<SectionInfo<'data>>; 4]);
+
+impl<'data> SegmentData<'data> {
+    pub fn new() -> Self {
+        Self([Vec::new(), Vec::new(), Vec::new(), Vec::new()])
+    }
+
+    pub fn append_section(&mut self, section: Section<'data>) -> Result<(), Error> {
+        match section {
+            Section::Text(si) => self.0[SI_TEXT].push(si),
+            Section::Data(si, false) => self.0[SI_DATA].push(si),
+            Section::Data(si, true) => self.0[SI_RODATA].push(si),
+            Section::Bss(si) => self.0[SI_BSS].push(si),
+        }
+
+        Ok(())
+    }
+
+    pub fn iter_mut(
+        &mut self,
+    ) -> impl Iterator<Item = (&'static str, &mut Vec<SectionInfo<'data>>)> {
+        self.0
+            .iter_mut()
+            .enumerate()
+            .map(|(i, s)| (SEGMENT_NAMES[i], s))
+    }
+
+    // .text + .rodata
+    pub fn program_size(&self) -> u64 {
+        let text_iter = self.0[SI_TEXT].iter();
+        let rodata_iter = self.0[SI_RODATA].iter();
+
+        let mut result = 0u64;
+        for section in text_iter.chain(rodata_iter) {
+            result += section.size
+        }
+
+        result
+    }
+
+    // data
+    pub fn data_size(&self) -> u64 {
+        let mut result = 0u64;
+        for section in self.0[SI_DATA].iter() {
+            result += section.size
+        }
+
+        result
+    }
+
+    // bss
+    pub fn bss_size(&self) -> u64 {
+        let mut result = 0u64;
+        for section in self.0[SI_BSS].iter() {
+            result += section.size
+        }
+
+        result
+    }
+}
+
+impl Default for SegmentData<'_> {
+    fn default() -> Self {
+        Self::new()
+    }
+}