diff options
Diffstat (limited to 'gdb/solib-svr4.c')
| -rw-r--r-- | gdb/solib-svr4.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c index 8378eca..398123f 100644 --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -3093,6 +3093,37 @@ svr4_truncate_ptr (CORE_ADDR addr) return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (current_inferior ()->arch ())) - 1); } +/* Find the LOAD-able program header in ABFD that contains ASECT. Return + NULL if no such header can be found. */ + +static Elf_Internal_Phdr * +find_loadable_elf_internal_phdr (bfd *abfd, bfd_section *asect) +{ + Elf_Internal_Ehdr *ehdr = elf_tdata (abfd)->elf_header; + Elf_Internal_Phdr *phdr = elf_tdata (abfd)->phdr; + + for (int i = 0; i < ehdr->e_phnum; i++) + { + if (phdr[i].p_type == PT_LOAD) + { + /* A section without the SEC_LOAD flag is a no-bits section + (e.g. .bss) and has zero size within ABFD. */ + ULONGEST section_file_size + = (((bfd_section_flags (asect) & SEC_LOAD) != 0) + ? bfd_section_size (asect) + : 0); + + if (asect->filepos >= phdr[i].p_offset + && ((asect->filepos + section_file_size) + <= (phdr[i].p_offset + phdr[i].p_filesz))) + return &phdr[i]; + } + } + + return nullptr; +} + +/* Implement solib_ops::relocate_section_addresses() for svr4 targets. */ static void svr4_relocate_section_addresses (solib &so, target_section *sec) @@ -3101,6 +3132,74 @@ svr4_relocate_section_addresses (solib &so, target_section *sec) sec->addr = svr4_truncate_ptr (sec->addr + lm_addr_check (so, abfd)); sec->endaddr = svr4_truncate_ptr (sec->endaddr + lm_addr_check (so, abfd)); + + struct bfd_section *asect = sec->the_bfd_section; + gdb_assert (asect != nullptr); + + /* Update the address range of SO based on ASECT. */ + if ((bfd_section_flags (asect) & SEC_ALLOC) != 0 + && bfd_get_flavour (abfd) == bfd_target_elf_flavour) + { + /* First, SO must cover the contents of ASECT. */ + if (so.addr_low == 0 || sec->addr < so.addr_low) + so.addr_low = sec->addr; + + if (so.addr_high == 0 || sec->endaddr > so.addr_high) + so.addr_high = sec->endaddr; + + gdb_assert (so.addr_low <= so.addr_high); + + /* But we can do better. Find the program header which contains + ASECT, and figure out its extents. This gives an larger possible + region for SO. */ + Elf_Internal_Phdr *phdr = find_loadable_elf_internal_phdr (abfd, asect); + + if (phdr != nullptr) + { + /* Figure out the alignment required by this segment. */ + ULONGEST minpagesize = get_elf_backend_data (abfd)->minpagesize; + ULONGEST segment_alignment + = std::max (minpagesize, static_cast<ULONGEST> (phdr->p_align)); + ULONGEST at_pagesz; + if (target_auxv_search (AT_PAGESZ, &at_pagesz) > 0) + segment_alignment = std::max (segment_alignment, at_pagesz); + + /* The offset of this section within the segment. */ + ULONGEST section_offset = asect->vma - phdr->p_vaddr; + + /* The start address for the segment, without alignment. */ + CORE_ADDR unaligned_start = sec->addr - section_offset; + + /* And the start address with downward alignment. */ + CORE_ADDR aligned_start + = align_down (unaligned_start, segment_alignment); + + /* The end address of the segment depends on its size. Start + with the size as described in the ELF. This check of the + memory size and file size is what BFD does, so assume it + knows best and copy this logic. */ + ULONGEST seg_size = std::max (phdr->p_memsz, phdr->p_filesz); + + /* But by aligning the start address down we need to also include + that difference in the segment size. */ + seg_size += (unaligned_start - aligned_start); + + /* And align the segment size upward. */ + seg_size = align_up (seg_size, segment_alignment); + + /* Finally, we can compute the end address. */ + CORE_ADDR end = aligned_start + seg_size; + + /* And now we can update the extend of SO. */ + if (so.addr_low == 0 || aligned_start < so.addr_low) + so.addr_low = aligned_start; + + if (so.addr_high == 0 || end > so.addr_high) + so.addr_high = end; + + gdb_assert (so.addr_low <= so.addr_high); + } + } } |