diff options
Diffstat (limited to 'bfd/elfcode.h')
| -rw-r--r-- | bfd/elfcode.h | 153 |
1 files changed, 92 insertions, 61 deletions
diff --git a/bfd/elfcode.h b/bfd/elfcode.h index 20101be..f840065 100644 --- a/bfd/elfcode.h +++ b/bfd/elfcode.h @@ -1587,37 +1587,40 @@ elf_debug_file (Elf_Internal_Ehdr *ehdrp) #endif /* Create a new BFD as if by bfd_openr. Rather than opening a file, - reconstruct an ELF file by reading the segments out of remote memory - based on the ELF file header at EHDR_VMA and the ELF program headers it - points to. If not null, *LOADBASEP is filled in with the difference - between the VMAs from which the segments were read, and the VMAs the - file headers (and hence BFD's idea of each section's VMA) put them at. - - The function TARGET_READ_MEMORY is called to copy LEN bytes from the - remote memory at target address VMA into the local buffer at MYADDR; it - should return zero on success or an `errno' code on failure. TEMPL must - be a BFD for a target with the word size and byte order found in the - remote memory. */ + reconstruct an ELF file by reading the segments out of remote + memory based on the ELF file header at EHDR_VMA and the ELF program + headers it points to. If non-zero, SIZE is the known extent of the + object. If not null, *LOADBASEP is filled in with the difference + between the VMAs from which the segments were read, and the VMAs + the file headers (and hence BFD's idea of each section's VMA) put + them at. + + The function TARGET_READ_MEMORY is called to copy LEN bytes from + the remote memory at target address VMA into the local buffer at + MYADDR; it should return zero on success or an `errno' code on + failure. TEMPL must be a BFD for a target with the word size and + byte order found in the remote memory. */ bfd * NAME(_bfd_elf,bfd_from_remote_memory) (bfd *templ, bfd_vma ehdr_vma, + size_t size, bfd_vma *loadbasep, int (*target_read_memory) (bfd_vma, bfd_byte *, bfd_size_type)) { Elf_External_Ehdr x_ehdr; /* Elf file header, external form */ Elf_Internal_Ehdr i_ehdr; /* Elf file header, internal form */ Elf_External_Phdr *x_phdrs; - Elf_Internal_Phdr *i_phdrs, *last_phdr; + Elf_Internal_Phdr *i_phdrs, *last_phdr, *first_phdr; bfd *nbfd; struct bfd_in_memory *bim; - int contents_size; bfd_byte *contents; int err; unsigned int i; + bfd_vma high_offset; + bfd_vma shdr_end; bfd_vma loadbase; - bfd_boolean loadbase_set; /* Read in the ELF header in external format. */ err = target_read_memory (ehdr_vma, (bfd_byte *) &x_ehdr, sizeof x_ehdr); @@ -1677,10 +1680,7 @@ NAME(_bfd_elf,bfd_from_remote_memory) x_phdrs = (Elf_External_Phdr *) bfd_malloc (i_ehdr.e_phnum * (sizeof *x_phdrs + sizeof *i_phdrs)); if (x_phdrs == NULL) - { - bfd_set_error (bfd_error_no_memory); - return NULL; - } + return NULL; err = target_read_memory (ehdr_vma + i_ehdr.e_phoff, (bfd_byte *) x_phdrs, i_ehdr.e_phnum * sizeof x_phdrs[0]); if (err) @@ -1692,34 +1692,44 @@ NAME(_bfd_elf,bfd_from_remote_memory) } i_phdrs = (Elf_Internal_Phdr *) &x_phdrs[i_ehdr.e_phnum]; - contents_size = 0; + high_offset = 0; + loadbase = 0; + first_phdr = NULL; last_phdr = NULL; - loadbase = ehdr_vma; - loadbase_set = FALSE; for (i = 0; i < i_ehdr.e_phnum; ++i) { elf_swap_phdr_in (templ, &x_phdrs[i], &i_phdrs[i]); if (i_phdrs[i].p_type == PT_LOAD) { - bfd_vma segment_end; - segment_end = (i_phdrs[i].p_offset + i_phdrs[i].p_filesz - + i_phdrs[i].p_align - 1) & -i_phdrs[i].p_align; - if (segment_end > (bfd_vma) contents_size) - contents_size = segment_end; - - /* LOADADDR is the `Base address' from the gELF specification: - `lowest p_vaddr value for a PT_LOAD segment' is P_VADDR from the - first PT_LOAD as PT_LOADs are ordered by P_VADDR. */ - if (!loadbase_set && (i_phdrs[i].p_offset & -i_phdrs[i].p_align) == 0) + bfd_vma segment_end = i_phdrs[i].p_offset + i_phdrs[i].p_filesz; + + if (segment_end > high_offset) { - loadbase = ehdr_vma - (i_phdrs[i].p_vaddr & -i_phdrs[i].p_align); - loadbase_set = TRUE; + high_offset = segment_end; + last_phdr = &i_phdrs[i]; } - last_phdr = &i_phdrs[i]; + /* If this program header covers offset zero, where the file + header sits, then we can figure out the loadbase. */ + if (first_phdr == NULL) + { + bfd_vma p_offset = i_phdrs[i].p_offset; + bfd_vma p_vaddr = i_phdrs[i].p_vaddr; + + if (i_phdrs[i].p_align > 1) + { + p_offset &= -i_phdrs[i].p_align; + p_vaddr &= -i_phdrs[i].p_align; + } + if (p_offset == 0) + { + loadbase = ehdr_vma - p_vaddr; + first_phdr = &i_phdrs[i]; + } + } } } - if (last_phdr == NULL) + if (high_offset == 0) { /* There were no PT_LOAD segments, so we don't have anything to read. */ free (x_phdrs); @@ -1727,40 +1737,64 @@ NAME(_bfd_elf,bfd_from_remote_memory) return NULL; } - /* Trim the last segment so we don't bother with zeros in the last page - that are off the end of the file. However, if the extra bit in that - page includes the section headers, keep them. */ - if ((bfd_vma) contents_size > last_phdr->p_offset + last_phdr->p_filesz - && (bfd_vma) contents_size >= (i_ehdr.e_shoff - + i_ehdr.e_shnum * i_ehdr.e_shentsize)) + shdr_end = 0; + if (i_ehdr.e_shoff != 0 && i_ehdr.e_shnum != 0 && i_ehdr.e_shentsize != 0) { - contents_size = last_phdr->p_offset + last_phdr->p_filesz; - if ((bfd_vma) contents_size < (i_ehdr.e_shoff - + i_ehdr.e_shnum * i_ehdr.e_shentsize)) - contents_size = i_ehdr.e_shoff + i_ehdr.e_shnum * i_ehdr.e_shentsize; + shdr_end = i_ehdr.e_shoff + i_ehdr.e_shnum * i_ehdr.e_shentsize; + + if (last_phdr->p_filesz != last_phdr->p_memsz) + { + /* If the last PT_LOAD header has a bss area then ld.so will + have cleared anything past p_filesz, zapping the section + headers. */ + } + else if (size >= shdr_end) + high_offset = shdr_end; + else + { + bfd_vma page_size = get_elf_backend_data (templ)->minpagesize; + bfd_vma segment_end = last_phdr->p_offset + last_phdr->p_filesz; + + /* Assume we loaded full pages, allowing us to sometimes see + section headers. */ + if (page_size > 1 && shdr_end > segment_end) + { + bfd_vma page_end = (segment_end + page_size - 1) & -page_size; + + if (page_end >= shdr_end) + /* Whee, section headers covered. */ + high_offset = shdr_end; + } + } } - else - contents_size = last_phdr->p_offset + last_phdr->p_filesz; /* Now we know the size of the whole image we want read in. */ - contents = (bfd_byte *) bfd_zmalloc (contents_size); + contents = (bfd_byte *) bfd_zmalloc (high_offset); if (contents == NULL) { free (x_phdrs); - bfd_set_error (bfd_error_no_memory); return NULL; } for (i = 0; i < i_ehdr.e_phnum; ++i) if (i_phdrs[i].p_type == PT_LOAD) { - bfd_vma start = i_phdrs[i].p_offset & -i_phdrs[i].p_align; - bfd_vma end = (i_phdrs[i].p_offset + i_phdrs[i].p_filesz - + i_phdrs[i].p_align - 1) & -i_phdrs[i].p_align; - if (end > (bfd_vma) contents_size) - end = contents_size; - err = target_read_memory ((loadbase + i_phdrs[i].p_vaddr) - & -i_phdrs[i].p_align, + bfd_vma start = i_phdrs[i].p_offset; + bfd_vma end = start + i_phdrs[i].p_filesz; + bfd_vma vaddr = i_phdrs[i].p_vaddr; + + /* Extend the beginning of the first pt_load to cover file + header and program headers, if we proved earlier that its + aligned offset is 0. */ + if (first_phdr == &i_phdrs[i]) + { + vaddr -= start; + start = 0; + } + /* Extend the end of the last pt_load to cover section headers. */ + if (last_phdr == &i_phdrs[i]) + end = high_offset; + err = target_read_memory (loadbase + vaddr, contents + start, end - start); if (err) { @@ -1775,8 +1809,7 @@ NAME(_bfd_elf,bfd_from_remote_memory) /* If the segments visible in memory didn't include the section headers, then clear them from the file header. */ - if ((bfd_vma) contents_size < (i_ehdr.e_shoff - + i_ehdr.e_shnum * i_ehdr.e_shentsize)) + if (high_offset < shdr_end) { memset (&x_ehdr.e_shoff, 0, sizeof x_ehdr.e_shoff); memset (&x_ehdr.e_shnum, 0, sizeof x_ehdr.e_shnum); @@ -1792,7 +1825,6 @@ NAME(_bfd_elf,bfd_from_remote_memory) if (bim == NULL) { free (contents); - bfd_set_error (bfd_error_no_memory); return NULL; } nbfd = _bfd_new_bfd (); @@ -1800,12 +1832,11 @@ NAME(_bfd_elf,bfd_from_remote_memory) { free (bim); free (contents); - bfd_set_error (bfd_error_no_memory); return NULL; } nbfd->filename = xstrdup ("<in-memory>"); nbfd->xvec = templ->xvec; - bim->size = contents_size; + bim->size = high_offset; bim->buffer = contents; nbfd->iostream = bim; nbfd->flags = BFD_IN_MEMORY; |