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dyld: add Image.rebind()

This commit is contained in:
Astro 2020-07-14 01:30:11 +02:00
parent 12ba867268
commit 49d93e20dd
2 changed files with 31 additions and 0 deletions

View File

@ -93,6 +93,7 @@ extern fn dl_unwind_find_exidx(pc: u32, len_ptr: *mut u32) -> u32 {
pub struct Library {
pub image: Image,
pub arch: Arch,
dyn_section: DynamicSection,
}
@ -163,6 +164,11 @@ impl Library {
Ok(self.strtab().get(offset..offset + size)
.ok_or("cannot read symbol name")?)
}
/// Rebind Rela by `name` to a new `addr`
pub fn rebind(&self, name: &[u8], addr: *const ()) -> Result<(), Error> {
reloc::rebind(self.arch, self, name, addr as Elf32_Word)
}
}
pub fn load(
@ -235,6 +241,7 @@ pub fn load(
debug!("Relocating {} rela, {} rel, {} pltrel",
dyn_section.rela.len(), dyn_section.rel.len(), dyn_section.pltrel.len());
let lib = Library {
arch,
image,
dyn_section
};

View File

@ -133,3 +133,27 @@ pub fn relocate<R: Relocatable>(
lib.image.write(rel.offset(), value)
}
pub fn rebind(
arch: Arch, lib: &Library, name: &[u8], value: Elf32_Word
) -> Result<(), Error> {
for rela in lib.pltrel() {
let rel_type = RelType::new(arch, rela.type_info())
.ok_or("unsupported relocation type")?;
match rel_type {
RelType::Lookup => {
let sym = lib.symtab().get(ELF32_R_SYM(rela.r_info) as usize)
.ok_or("symbol out of bounds of symbol table")?;
let sym_name = lib.name_starting_at(sym.st_name as usize)?;
if sym_name == name {
lib.image.write(rela.offset(), value)?
}
}
// No associated symbols for other relocation types.
_ => {}
}
}
Ok(())
}