diff options
Diffstat (limited to 'checklink/ELF_utils.ml')
| -rw-r--r-- | checklink/ELF_utils.ml | 90 |
1 files changed, 66 insertions, 24 deletions
diff --git a/checklink/ELF_utils.ml b/checklink/ELF_utils.ml index 4d90160..898c778 100644 --- a/checklink/ELF_utils.ml +++ b/checklink/ELF_utils.ml @@ -18,10 +18,16 @@ let section_bitstring_noelf let section_bitstring (e: elf): int -> bitstring = section_bitstring_noelf e.e_bitstring e.e_shdra -let physical_offset_of_vaddr (e: elf)(sndx: int)(vaddr: int32): int32 = - let shdr = e.e_shdra.(sndx) in - Int32.(add shdr.sh_offset (sub vaddr shdr.sh_addr)) +let physical_offset_of_vaddr (e: elf)(vaddr: int32): int32 option = + begin match e.e_sym_phdr vaddr with + | None -> None + | Some(pndx) -> + let phdr = e.e_phdra.(pndx) in + let vaddr_ofs = Safe32.(vaddr - phdr.p_vaddr) in + Some(Safe32.(phdr.p_offset + vaddr_ofs)) + end +(* TODO: could make this more efficient, but it's not often called *) let section_at_vaddr (e: elf)(vaddr: int32): int option = array_exists (fun shdr -> @@ -30,31 +36,67 @@ let section_at_vaddr (e: elf)(vaddr: int32): int option = e.e_shdra (** - Returns the bitstring of the specified size beginning at the specified - virtual address within the specified section. + Returns the bitstring of the specified byte size beginning at the specified + virtual address, along with its physical byte offset and physical byte size, + that is, the space it occupies in the file. *) -let bitstring_at_vaddr e sndx vaddr size = - let shdr = e.e_shdra.(sndx) in - if vaddr < shdr.sh_addr || Safe32.(shdr.sh_addr + shdr.sh_size) <= vaddr - then None - else - let bs = section_bitstring e sndx in - let bit_ofs = Safe.(8 * Safe32.(to_int (vaddr - shdr.sh_addr))) in - Some(Bitstring.subbitstring bs bit_ofs size) +let bitstring_at_vaddr (e: elf)(vaddr: int32)(size:int32): + (bitstring * int32 * int32) option = + match e.e_sym_phdr vaddr with + | None -> None + | Some(pndx) -> + let phdr = e.e_phdra.(pndx) in + let phdr_mem_first = phdr.p_vaddr in + let phdr_mem_last = Safe32.(phdr.p_vaddr + phdr.p_memsz - 1l) in + let vaddr_mem_first = vaddr in + let vaddr_mem_last = Safe32.(vaddr + size - 1l) in + if not (phdr_mem_first <= vaddr_mem_first && vaddr_mem_last <= phdr_mem_last) + then None (* we're overlapping segments *) + else + let vaddr_relative_ofs = Safe32.(vaddr_mem_first - phdr_mem_first) in + let vaddr_file_ofs = Safe32.(phdr.p_offset + vaddr_relative_ofs) in + if phdr.p_filesz = 0l || vaddr_relative_ofs > phdr.p_filesz + then + Some( + Bitstring.create_bitstring Safe32.(to_int (8l * size)), + phdr.p_offset, (* whatever? *) + 0l + ) + else if Safe32.(vaddr_relative_ofs + size) > phdr.p_filesz + then + let bit_start = Safe32.(to_int (8l * vaddr_file_ofs)) in + let vaddr_file_len = Safe32.(phdr.p_filesz - vaddr_relative_ofs) in + let bit_len = Safe32.(to_int (8l * vaddr_file_len)) in + let first = Bitstring.subbitstring e.e_bitstring bit_start bit_len in + let rest = Bitstring.create_bitstring (8 * Safe32.to_int size - bit_len) in + Some( + Bitstring.concat [first; rest], + vaddr_file_ofs, + vaddr_file_len + ) + else + let bit_start = Safe32.(to_int (8l * (phdr.p_offset + vaddr_relative_ofs))) in + let bit_len = Safe.(8 * Safe32.to_int size) in + Some( + Bitstring.subbitstring e.e_bitstring bit_start bit_len, + vaddr_file_ofs, + size + ) (** - Returns the entire bitstring that begins at the specified virtual address - within the specified section and ends at the end of the file. This is useful - when you don't know the sections size yet. + Returns the entire bitstring that begins at the specified virtual address and + ends at the end of the segment. *) -let bitstring_at_vaddr_nosize (e: elf)(sndx: int)(vaddr: int32): bitstring option = - let shdr = e.e_shdra.(sndx) in - if vaddr < shdr.sh_addr || Safe32.(shdr.sh_addr + shdr.sh_size) <= vaddr - then None - else - let bs = section_bitstring e sndx in - let bit_ofs = Safe.(8 * Safe32.(to_int (vaddr - shdr.sh_addr))) in - Some(Bitstring.dropbits bit_ofs bs) +let bitstring_at_vaddr_nosize (e: elf)(vaddr: int32): + (bitstring * int32 * int32) option = + match e.e_sym_phdr vaddr with + | None -> None + | Some(pndx) -> + let phdr = e.e_phdra.(pndx) in + let first_byte_vaddr = vaddr in + let last_byte_vaddr = Safe32.(phdr.p_vaddr + phdr.p_memsz - 1l) in + let size = Safe32.(last_byte_vaddr - first_byte_vaddr + 1l) in + bitstring_at_vaddr e vaddr size (** Removes symbol version for GCC's symbols. |