diff options
| -rw-r--r-- | src/linker.rs | 50 | ||||
| -rw-r--r-- | test.c | 8 |
2 files changed, 31 insertions, 27 deletions
diff --git a/src/linker.rs b/src/linker.rs index 42bf7a8..9666a87 100644 --- a/src/linker.rs +++ b/src/linker.rs @@ -406,16 +406,16 @@ impl SourceRanges { true } - fn get_value(&self, offset: u64) -> Option<u64> { - let (range, &value) = self.map.range(..=(offset, u64::MAX)).last()?; + fn translate_offset(&self, offset: u64) -> Option<u64> { + let (range, &out) = self.map.range(..=(offset, u64::MAX)).last()?; if offset >= range.0 && offset < range.0 + range.1 { - Some(value) + Some(out + (offset - range.0)) } else { None } } - fn set_values(&mut self, size: &mut u64) { + fn set_output_offsets(&mut self, size: &mut u64) { for (range, value) in self.map.iter_mut() { // we should only call this function once assert_eq!(*value, 0); @@ -445,7 +445,7 @@ impl RangeSet { fn to_map(mut self) -> OffsetMap { let mut size = 0u64; for range in self.ranges.iter_mut() { - range.set_values(&mut size) + range.set_output_offsets(&mut size) } OffsetMap { size, @@ -461,13 +461,13 @@ struct OffsetMap { } impl OffsetMap { - fn get(&self, src: SourceId, offset: u64) -> Option<u64> { - self.ranges[src.0 as usize].get_value(offset) + fn translate_offset(&self, src: SourceId, offset: u64) -> Option<u64> { + self.ranges[src.0 as usize].translate_offset(offset) } /// get offset in data section where relocation should be applied - fn get_rel_data_offset(&self, rel: &Relocation) -> Option<u64> { - self.get(rel.r#where.0, rel.r#where.1) + fn translate_rel_offset(&self, rel: &Relocation) -> Option<u64> { + self.translate_offset(rel.r#where.0, rel.r#where.1) } fn size(&self) -> u64 { @@ -605,9 +605,9 @@ impl LinkerOutput { use SymbolValue::*; match value { Data { source, offset, .. } => { - // in theory, this should never panic - map - .get(*source, *offset) + // in theory, this should never panic, because we compute OffsetMap + // to include all dependent symbols. + map.translate_offset(*source, *offset) .unwrap() + self.data_addr() } @@ -621,7 +621,7 @@ impl LinkerOutput { } /// output the executable. - pub fn write(&self, mut out: impl Write + Seek) -> LinkResult<()> { + pub fn write(&self, mut out: impl Write + Seek, entry_point: u64) -> LinkResult<()> { let u64_to_u32 = LinkError::u64_to_u32; let usize_to_u32 = LinkError::usize_to_u32; @@ -732,7 +732,7 @@ impl LinkerOutput { // apparently you're supposed to set this to zero if there are no sections. // at least, that's what readelf seems to think. shentsize: 0, - entry: u64_to_u32(self.data_addr())?, + entry: u64_to_u32(entry_point)?, ..Default::default() }; out.write_all(&ehdr.to_bytes())?; @@ -1049,7 +1049,7 @@ impl<'a> Linker<'a> { /// Apply relocation to executable. fn apply_relocation(&self, exec: &mut LinkerOutput, map: &OffsetMap, rel: &Relocation) -> LinkResult<()> { - let apply_offset = match map.get_rel_data_offset(rel) { + let apply_offset = match map.translate_rel_offset(rel) { Some(data_offset) => data_offset, None => { // this relocation isn't in a data section so there's nothing we can do about it @@ -1149,11 +1149,12 @@ impl<'a> Linker<'a> { let mut ranges = RangeSet::new(self.sources.len()); let entry_value = &self.symbols.get_info_from_id(entry_id).value; - if let SymbolValue::Data { source, offset, size } = entry_value { - self.require_range(&mut ranges, *source, *offset, *size); - } else { - return Err(LinkError::EntryNoData(entry.into())); - } + let (entry_source, entry_offset, entry_size) = match entry_value { + SymbolValue::Data { source, offset, size } => (*source, *offset, *size), + _ => return Err(LinkError::EntryNoData(entry.into())), + }; + + self.require_range(&mut ranges, entry_source, entry_offset, entry_size); // compute offset map let offset_map = ranges.to_map(); @@ -1165,11 +1166,15 @@ impl<'a> Linker<'a> { let dest_end = dest_start + size as usize; let src_start = src_offset as usize; let src_end = src_start + size as usize; + let dest_addr = dest_offset + exec.data_addr(); + println!("{source:?}@{src_offset:x} => {:x}..{:x}", dest_addr,dest_addr+size); data_section[dest_start..dest_end].copy_from_slice( &self.source_data[source.0 as usize][src_start..src_end] ); }); + println!("{:?}", data_section); + exec.set_data(data_section); for rel_map in self.relocations.iter() { @@ -1177,8 +1182,11 @@ impl<'a> Linker<'a> { self.apply_relocation(&mut exec, &offset_map, rel)?; } } + println!("{:?}", exec.data); - exec.write(out) + // this should never panic, since we did require_range on the entry point. + let entry_addr = offset_map.translate_offset(entry_source, entry_offset).unwrap() + exec.data_addr(); + exec.write(out, entry_addr) } /// Easy linking API. Just provide a path and the name of the entry function. @@ -1,10 +1,6 @@ #include<stdio.h> - +#include <stdlib.h> void entry(void) { printf("hi\n"); - __asm__ ( - "mov $1, %eax\n" - "mov $0, %ebx\n" - "int $0x80\n" - ); + exit(0); } |