diff options
| -rw-r--r-- | Userland/Libraries/LibELF/DynamicLoader.cpp | 37 |
1 files changed, 22 insertions, 15 deletions
diff --git a/Userland/Libraries/LibELF/DynamicLoader.cpp b/Userland/Libraries/LibELF/DynamicLoader.cpp index 9aa46600b1..18d6b31780 100644 --- a/Userland/Libraries/LibELF/DynamicLoader.cpp +++ b/Userland/Libraries/LibELF/DynamicLoader.cpp @@ -286,25 +286,38 @@ void DynamicLoader::load_program_headers() ASSERT(!text_region.value().is_writable()); - // First, we map the text *and* data segments, in order to allocate enough VM - // to hold both contiguously in the address space. + // First, we make a dummy reservation mapping, in order to allocate enough VM + // to hold both text+data contiguously in the address space. Checked<size_t> total_mapping_size; total_mapping_size = text_region.value().required_load_size(); total_mapping_size += data_region.value().required_load_size(); ASSERT(!total_mapping_size.has_overflow()); + auto* reservation = mmap(requested_load_address, total_mapping_size.value(), PROT_NONE, MAP_ANON | MAP_PRIVATE | MAP_NORESERVE, 0, 0); + if (reservation == MAP_FAILED) { + perror("mmap reservation"); + ASSERT_NOT_REACHED(); + } + + // Then we unmap the reservation. + if (munmap(reservation, total_mapping_size.value()) < 0) { + perror("munmap reservation"); + ASSERT_NOT_REACHED(); + } + + // Now we can map the text segment at the reserved address. auto* text_segment_begin = (u8*)mmap_with_name( - requested_load_address, - total_mapping_size.value(), + reservation, + text_region.value().required_load_size(), PROT_READ, text_mmap_flags, m_image_fd, text_region.value().offset(), String::formatted("{}: .text", m_filename).characters()); - if (MAP_FAILED == text_segment_begin) { - perror("mmap text / initial segment"); + if (text_segment_begin == MAP_FAILED) { + perror("mmap text"); ASSERT_NOT_REACHED(); } @@ -312,19 +325,13 @@ void DynamicLoader::load_program_headers() m_text_segment_size = text_region.value().required_load_size(); m_text_segment_load_address = VirtualAddress { (FlatPtr)text_segment_begin }; - // Then, we unmap the data segment part of the above combined VM allocation. - auto* data_segment_address = (u8*)text_segment_begin + text_region.value().required_load_size(); - if (munmap(data_segment_address, data_region.value().required_load_size()) < 0) { - perror("munmap"); - ASSERT_NOT_REACHED(); - } - if (m_elf_image.is_dynamic()) m_dynamic_section_address = dynamic_region_desired_vaddr.offset(m_text_segment_load_address.get()); else m_dynamic_section_address = dynamic_region_desired_vaddr; - // Finally, we remap the data segment, this time privately. + // Finally, we make an anonymous mapping for the data segment. Contents are then copied from the file. + auto* data_segment_address = (u8*)text_segment_begin + text_region.value().required_load_size(); auto* data_segment = (u8*)mmap_with_name( data_segment_address, data_region.value().required_load_size(), @@ -335,7 +342,7 @@ void DynamicLoader::load_program_headers() String::formatted("{}: .data", m_filename).characters()); if (MAP_FAILED == data_segment) { - perror("mmap data segment"); + perror("mmap data"); ASSERT_NOT_REACHED(); } |