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Various enhancements #2

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7054df1
Set default table style to UTF8_NO_BORDERS
JonathonReinhart May 14, 2025
14ff34c
Add a desription before each output table
JonathonReinhart May 14, 2025
a06d9e1
Print segment to section mapping
JonathonReinhart May 14, 2025
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166 changes: 156 additions & 10 deletions src/rust-readelf.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,12 @@ struct Args {
notes: bool,
}

fn table() -> Table {
let mut table = Table::new();
table.load_preset(comfy_table::presets::UTF8_NO_BORDERS);
table
}

// _____ _ _ _ _ _
// | ___(_) | ___| | | | ___ __ _ __| | ___ _ __
// | |_ | | |/ _ \ |_| |/ _ \/ _` |/ _` |/ _ \ '__|
Expand Down Expand Up @@ -95,12 +101,14 @@ fn print_file_header(ehdr: &elf::file::FileHeader<AnyEndian>) {
//

fn print_program_headers(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
let mut table = Table::new();
let mut table = table();
table.set_header([
"p_type", "p_offset", "p_vaddr", "p_paddr", "p_filesz", "p_memsz", "p_align", "p_flags",
"Idx", "p_type", "p_offset", "p_vaddr", "p_paddr", "p_filesz", "p_memsz", "p_align",
"p_flags",
]);
for phdr in elf_file.segments() {
for (i, phdr) in elf_file.segments().iter().enumerate() {
let cells: Vec<Cell> = vec![
i.into(),
elf::to_str::p_type_to_string(phdr.p_type).into(),
format!("{:#x}", phdr.p_offset).into(),
format!("{:#x}", phdr.p_vaddr).into(),
Expand All @@ -112,7 +120,126 @@ fn print_program_headers(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
];
table.add_row(cells);
}
println!("Program Headers (Segments):");
println!();
println!("{table}");
println!();
}

fn print_segment_mapping(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
use elf::abi::{PT_TLS, SHF_TLS, SHT_NOBITS, SHT_NULL};

let mut table = table();
table.set_header(["Segment", "Sections"]);

let segments = elf_file.segments().to_vec();
for (i, seg) in segments.iter().enumerate() {
let (sections, sec_strtab) = elf_file
.section_headers_with_strtab()
.expect("Could not get section headers");
let sec_strtab = sec_strtab.expect("Could not get section header strtab");

let mut section_names: Vec<String> = vec![];
for sec in sections {
if sec.sh_type == SHT_NULL {
continue;
}
if ((sec.sh_flags as u32 & SHF_TLS) != 0)
&& sec.sh_type == SHT_NOBITS
&& seg.p_type == PT_TLS
{
// .tbss
continue;
}

if elf_section_in_segment(sec, seg) {
let name = if sec.sh_name == 0 {
"<null>"
} else {
sec_strtab.get(sec.sh_name.try_into().unwrap()).unwrap()
};
section_names.push(name.to_string());
}
}

let cells: Vec<Cell> = vec![i.into(), section_names.join("\n").into()];
table.add_row(cells);
}
println!(" Section to segment mapping:");
println!();
println!("{table}");
println!();
}

fn elf_section_in_segment(
sec: &elf::section::SectionHeader,
seg: &elf::segment::ProgramHeader,
) -> bool {
// References:
// * binutils: ELF_SECTION_IN_SEGMENT_STRICT
// * pyelftools: Segment.section_in_segment()
use elf::abi::{
PT_DYNAMIC, PT_GNU_EH_FRAME, PT_GNU_RELRO, PT_GNU_STACK, PT_LOAD, PT_PHDR, PT_TLS,
SHF_ALLOC, SHF_TLS, SHT_NOBITS,
};

// Only PT_LOAD, PT_GNU_RELRO and PT_TLS segments can contain SHF_TLS sections.
if (sec.sh_flags as u32 & SHF_TLS) != 0 {
match seg.p_type {
PT_TLS | PT_GNU_RELRO | PT_LOAD => (),
_ => return false,
}
} else {
// PT_TLS segment contains only SHF_TLS sections, PT_PHDR no sections at all
match seg.p_type {
PT_TLS | PT_PHDR => return false,
_ => (),
}
}

// PT_LOAD and similar segments only have SHF_ALLOC sections.
if (sec.sh_flags as u32 & SHF_ALLOC) == 0 {
match seg.p_type {
PT_LOAD | PT_DYNAMIC | PT_GNU_EH_FRAME | PT_GNU_RELRO | PT_GNU_STACK => return false,
_ => (),
}
} else {
// For SHF_ALLOC section, see if its VMA is contained by the segment.
let sec_start = sec.sh_addr;
let sec_end = sec_start + sec.sh_size;

let seg_start = seg.p_vaddr;
let seg_end = seg_start + seg.p_memsz;

if sec_start < seg_start {
return false;
}
if sec_end > seg_end {
return false;
}
}

if sec.sh_type == SHT_NOBITS {
return true;
}

// Verify file offsets
{
let sec_f_start = sec.sh_offset;
let sec_f_end = sec_f_start + sec.sh_size;

let seg_f_start = seg.p_offset;
let seg_f_end = seg_f_start + seg.p_filesz;

if sec_f_start < seg_f_start {
return false;
}
if sec_f_end > seg_f_end {
return false;
}
}

return true;
}

// ____ _ _ _ _ _
Expand All @@ -127,7 +254,7 @@ fn print_section_table(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
.section_headers_with_strtab()
.expect("Failed to read section table and string table");
let (shdrs, strtab) = (shdrs, strtab.unwrap());
let mut table = Table::new();
let mut table = table();
table.set_header([
"index",
"name",
Expand Down Expand Up @@ -160,7 +287,10 @@ fn print_section_table(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
];
table.add_row(cells);
}
println!("Section Headers:");
println!();
println!("{table}");
println!();
}

// ____ _ _ _____ _ _
Expand All @@ -182,7 +312,7 @@ fn print_symbol_table(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
}
};

let mut table = Table::new();
let mut table = table();
table.set_header([
"ndx",
"value",
Expand All @@ -209,7 +339,10 @@ fn print_symbol_table(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
];
table.add_row(cells);
}
println!("Symbol Table:");
println!();
println!("{table}");
println!();
}

// ____ ____
Expand Down Expand Up @@ -249,7 +382,7 @@ fn print_dynamic_symbol_table(elf_file: &mut ElfStream<AnyEndian, std::fs::File>
.symbol_version_table()
.expect("Failed to parse GNU symbol versions");

let mut table = Table::new();
let mut table = table();
table.set_header([
"ndx",
"value",
Expand Down Expand Up @@ -291,7 +424,10 @@ fn print_dynamic_symbol_table(elf_file: &mut ElfStream<AnyEndian, std::fs::File>
];
table.add_row(cells);
}
println!("Dynamic symbols:");
println!();
println!("{table}");
println!();
}

// _ _
Expand All @@ -310,7 +446,7 @@ fn print_dynamic(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
}
};

let mut table = Table::new();
let mut table = table();
table.set_header(["d_tag", "d_ptr/d_val"]);
for d in dyns.iter() {
let d_tag_str = elf::to_str::d_tag_to_str(d.d_tag)
Expand All @@ -321,7 +457,10 @@ fn print_dynamic(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
];
table.add_row(cells);
}
println!("Dynamic:");
println!();
println!("{table}");
println!();
}

// _
Expand All @@ -332,7 +471,7 @@ fn print_dynamic(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
//

fn print_rels(rels: RelIterator<AnyEndian>) {
let mut table = Table::new();
let mut table = table();
table.set_header(["r_type", "r_sym", "r_offset"]);
for r in rels {
let cells: Vec<Cell> = vec![
Expand All @@ -342,11 +481,14 @@ fn print_rels(rels: RelIterator<AnyEndian>) {
];
table.add_row(cells);
}
println!("Rels:");
println!();
println!("{table}");
println!();
}

fn print_relas(relas: RelaIterator<AnyEndian>) {
let mut table = Table::new();
let mut table = table();
table.set_header(["r_type", "r_sym", "r_offset", "r_addend"]);
for r in relas {
let cells: Vec<Cell> = vec![
Expand All @@ -357,7 +499,10 @@ fn print_relas(relas: RelaIterator<AnyEndian>) {
];
table.add_row(cells);
}
println!("Relas:");
println!();
println!("{table}");
println!();
}

fn print_relocations(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
Expand Down Expand Up @@ -431,7 +576,7 @@ fn print_notes(elf_file: &mut ElfStream<AnyEndian, std::fs::File>) {
println!();
}
Note::Unknown(any) => {
let mut table = Table::new();
let mut table = table();
table.set_header(["type", "name", "desc"]);
let cells: Vec<Cell> = vec![
any.n_type.into(),
Expand Down Expand Up @@ -461,6 +606,7 @@ fn main() {

if args.program_headers {
print_program_headers(&mut elf_file);
print_segment_mapping(&mut elf_file);
}

if args.section_headers {
Expand Down