| /* ELF core file support for BFD. |
| Copyright (C) 1995-2021 Free Software Foundation, Inc. |
| |
| This file is part of BFD, the Binary File Descriptor library. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| MA 02110-1301, USA. */ |
| |
| char* |
| elf_core_file_failing_command (bfd *abfd) |
| { |
| return elf_tdata (abfd)->core->command; |
| } |
| |
| int |
| elf_core_file_failing_signal (bfd *abfd) |
| { |
| return elf_tdata (abfd)->core->signal; |
| } |
| |
| int |
| elf_core_file_pid (bfd *abfd) |
| { |
| return elf_tdata (abfd)->core->pid; |
| } |
| |
| bool |
| elf_core_file_matches_executable_p (bfd *core_bfd, bfd *exec_bfd) |
| { |
| char* corename; |
| |
| /* xvecs must match if both are ELF files for the same target. */ |
| |
| if (core_bfd->xvec != exec_bfd->xvec) |
| { |
| bfd_set_error (bfd_error_system_call); |
| return false; |
| } |
| |
| /* If both BFDs have identical build-ids, then they match. */ |
| if (core_bfd->build_id != NULL |
| && exec_bfd->build_id != NULL |
| && core_bfd->build_id->size == exec_bfd->build_id->size |
| && memcmp (core_bfd->build_id->data, exec_bfd->build_id->data, |
| core_bfd->build_id->size) == 0) |
| return true; |
| |
| /* See if the name in the corefile matches the executable name. */ |
| corename = elf_tdata (core_bfd)->core->program; |
| if (corename != NULL) |
| { |
| const char* execname = strrchr (bfd_get_filename (exec_bfd), '/'); |
| |
| execname = execname ? execname + 1 : bfd_get_filename (exec_bfd); |
| |
| if (strcmp (execname, corename) != 0) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /* Core files are simply standard ELF formatted files that partition |
| the file using the execution view of the file (program header table) |
| rather than the linking view. In fact, there is no section header |
| table in a core file. |
| |
| The process status information (including the contents of the general |
| register set) and the floating point register set are stored in a |
| segment of type PT_NOTE. We handcraft a couple of extra bfd sections |
| that allow standard bfd access to the general registers (.reg) and the |
| floating point registers (.reg2). */ |
| |
| bfd_cleanup |
| elf_core_file_p (bfd *abfd) |
| { |
| Elf_External_Ehdr x_ehdr; /* Elf file header, external form. */ |
| Elf_Internal_Ehdr *i_ehdrp; /* Elf file header, internal form. */ |
| Elf_Internal_Phdr *i_phdrp; /* Elf program header, internal form. */ |
| unsigned int phindex; |
| const struct elf_backend_data *ebd; |
| bfd_size_type amt; |
| |
| /* Read in the ELF header in external format. */ |
| if (bfd_bread (&x_ehdr, sizeof (x_ehdr), abfd) != sizeof (x_ehdr)) |
| { |
| if (bfd_get_error () != bfd_error_system_call) |
| goto wrong; |
| else |
| goto fail; |
| } |
| |
| /* Check the magic number. */ |
| if (! elf_file_p (&x_ehdr)) |
| goto wrong; |
| |
| /* FIXME: Check EI_VERSION here ! */ |
| |
| /* Check the address size ("class"). */ |
| if (x_ehdr.e_ident[EI_CLASS] != ELFCLASS) |
| goto wrong; |
| |
| /* Check the byteorder. */ |
| switch (x_ehdr.e_ident[EI_DATA]) |
| { |
| case ELFDATA2MSB: /* Big-endian. */ |
| if (! bfd_big_endian (abfd)) |
| goto wrong; |
| break; |
| case ELFDATA2LSB: /* Little-endian. */ |
| if (! bfd_little_endian (abfd)) |
| goto wrong; |
| break; |
| default: |
| goto wrong; |
| } |
| |
| /* Give abfd an elf_obj_tdata. */ |
| if (! (*abfd->xvec->_bfd_set_format[bfd_core]) (abfd)) |
| goto fail; |
| |
| /* Swap in the rest of the header, now that we have the byte order. */ |
| i_ehdrp = elf_elfheader (abfd); |
| elf_swap_ehdr_in (abfd, &x_ehdr, i_ehdrp); |
| |
| #if DEBUG & 1 |
| elf_debug_file (i_ehdrp); |
| #endif |
| |
| ebd = get_elf_backend_data (abfd); |
| |
| /* Check that the ELF e_machine field matches what this particular |
| BFD format expects. */ |
| |
| if (ebd->elf_machine_code != i_ehdrp->e_machine |
| && (ebd->elf_machine_alt1 == 0 |
| || i_ehdrp->e_machine != ebd->elf_machine_alt1) |
| && (ebd->elf_machine_alt2 == 0 |
| || i_ehdrp->e_machine != ebd->elf_machine_alt2)) |
| { |
| const bfd_target * const *target_ptr; |
| |
| if (ebd->elf_machine_code != EM_NONE) |
| goto wrong; |
| |
| /* This is the generic ELF target. Let it match any ELF target |
| for which we do not have a specific backend. */ |
| |
| for (target_ptr = bfd_target_vector; *target_ptr != NULL; target_ptr++) |
| { |
| const struct elf_backend_data *back; |
| |
| if ((*target_ptr)->flavour != bfd_target_elf_flavour) |
| continue; |
| back = xvec_get_elf_backend_data (*target_ptr); |
| if (back->s->arch_size != ARCH_SIZE) |
| continue; |
| if (back->elf_machine_code == i_ehdrp->e_machine |
| || (back->elf_machine_alt1 != 0 |
| && i_ehdrp->e_machine == back->elf_machine_alt1) |
| || (back->elf_machine_alt2 != 0 |
| && i_ehdrp->e_machine == back->elf_machine_alt2)) |
| { |
| /* target_ptr is an ELF backend which matches this |
| object file, so reject the generic ELF target. */ |
| goto wrong; |
| } |
| } |
| } |
| |
| /* If there is no program header, or the type is not a core file, then |
| we are hosed. */ |
| if (i_ehdrp->e_phoff == 0 || i_ehdrp->e_type != ET_CORE) |
| goto wrong; |
| |
| /* Does BFD's idea of the phdr size match the size |
| recorded in the file? */ |
| if (i_ehdrp->e_phentsize != sizeof (Elf_External_Phdr)) |
| goto wrong; |
| |
| /* If the program header count is PN_XNUM(0xffff), the actual |
| count is in the first section header. */ |
| if (i_ehdrp->e_shoff != 0 && i_ehdrp->e_phnum == PN_XNUM) |
| { |
| Elf_External_Shdr x_shdr; |
| Elf_Internal_Shdr i_shdr; |
| file_ptr where = (file_ptr) i_ehdrp->e_shoff; |
| |
| /* Seek to the section header table in the file. */ |
| if (bfd_seek (abfd, where, SEEK_SET) != 0) |
| goto fail; |
| |
| /* Read the first section header at index 0, and convert to internal |
| form. */ |
| if (bfd_bread (&x_shdr, sizeof (x_shdr), abfd) != sizeof (x_shdr)) |
| goto fail; |
| elf_swap_shdr_in (abfd, &x_shdr, &i_shdr); |
| |
| if (i_shdr.sh_info != 0) |
| { |
| i_ehdrp->e_phnum = i_shdr.sh_info; |
| if (i_ehdrp->e_phnum != i_shdr.sh_info) |
| goto wrong; |
| } |
| } |
| |
| /* Sanity check that we can read all of the program headers. |
| It ought to be good enough to just read the last one. */ |
| if (i_ehdrp->e_phnum > 1) |
| { |
| Elf_External_Phdr x_phdr; |
| Elf_Internal_Phdr i_phdr; |
| file_ptr where; |
| |
| /* Check that we don't have a totally silly number of |
| program headers. */ |
| if (i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (x_phdr) |
| || i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (i_phdr)) |
| goto wrong; |
| |
| where = (file_ptr)(i_ehdrp->e_phoff + (i_ehdrp->e_phnum - 1) * sizeof (x_phdr)); |
| if ((bfd_size_type) where <= i_ehdrp->e_phoff) |
| goto wrong; |
| |
| if (bfd_seek (abfd, where, SEEK_SET) != 0) |
| goto fail; |
| if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) |
| goto fail; |
| } |
| |
| /* Move to the start of the program headers. */ |
| if (bfd_seek (abfd, (file_ptr) i_ehdrp->e_phoff, SEEK_SET) != 0) |
| goto wrong; |
| |
| /* Allocate space for the program headers. */ |
| amt = sizeof (*i_phdrp) * i_ehdrp->e_phnum; |
| i_phdrp = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt); |
| if (!i_phdrp) |
| goto fail; |
| |
| elf_tdata (abfd)->phdr = i_phdrp; |
| |
| /* Read and convert to internal form. */ |
| for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) |
| { |
| Elf_External_Phdr x_phdr; |
| |
| if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) |
| goto fail; |
| |
| elf_swap_phdr_in (abfd, &x_phdr, i_phdrp + phindex); |
| } |
| |
| /* Set the machine architecture. Do this before processing the |
| program headers since we need to know the architecture type |
| when processing the notes of some systems' core files. */ |
| if (! bfd_default_set_arch_mach (abfd, ebd->arch, 0) |
| /* It's OK if this fails for the generic target. */ |
| && ebd->elf_machine_code != EM_NONE) |
| goto fail; |
| |
| /* Let the backend double check the format and override global |
| information. We do this before processing the program headers |
| to allow the correct machine (as opposed to just the default |
| machine) to be set, making it possible for grok_prstatus and |
| grok_psinfo to rely on the mach setting. */ |
| if (ebd->elf_backend_object_p != NULL |
| && ! ebd->elf_backend_object_p (abfd)) |
| goto wrong; |
| |
| /* Process each program header. */ |
| for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) |
| if (! bfd_section_from_phdr (abfd, i_phdrp + phindex, (int) phindex)) |
| goto fail; |
| |
| /* Check for core truncation. */ |
| { |
| bfd_size_type high = 0; |
| struct stat statbuf; |
| for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) |
| { |
| Elf_Internal_Phdr *p = i_phdrp + phindex; |
| if (p->p_filesz) |
| { |
| bfd_size_type current = p->p_offset + p->p_filesz; |
| if (high < current) |
| high = current; |
| } |
| } |
| if (bfd_stat (abfd, &statbuf) == 0) |
| { |
| if ((bfd_size_type) statbuf.st_size < high) |
| { |
| _bfd_error_handler |
| /* xgettext:c-format */ |
| (_("warning: %pB is truncated: expected core file " |
| "size >= %" PRIu64 ", found: %" PRIu64), |
| abfd, (uint64_t) high, (uint64_t) statbuf.st_size); |
| } |
| } |
| } |
| |
| /* Save the entry point from the ELF header. */ |
| abfd->start_address = i_ehdrp->e_entry; |
| return _bfd_no_cleanup; |
| |
| wrong: |
| bfd_set_error (bfd_error_wrong_format); |
| fail: |
| return NULL; |
| } |
| |
| /* Attempt to find a build-id in a core file from the core file BFD. |
| OFFSET is the file offset to a PT_LOAD segment that may contain |
| the build-id note. Returns TRUE upon success, FALSE otherwise. */ |
| |
| bool |
| NAME(_bfd_elf, core_find_build_id) |
| (bfd *abfd, |
| bfd_vma offset) |
| { |
| Elf_External_Ehdr x_ehdr; /* Elf file header, external form. */ |
| Elf_Internal_Ehdr i_ehdr; /* Elf file header, internal form. */ |
| Elf_Internal_Phdr *i_phdr; |
| unsigned int i; |
| size_t amt; |
| |
| /* Seek to the position of the segment at OFFSET. */ |
| if (bfd_seek (abfd, offset, SEEK_SET) != 0) |
| goto fail; |
| |
| /* Read in the ELF header in external format. */ |
| if (bfd_bread (&x_ehdr, sizeof (x_ehdr), abfd) != sizeof (x_ehdr)) |
| { |
| if (bfd_get_error () != bfd_error_system_call) |
| goto wrong; |
| else |
| goto fail; |
| } |
| |
| /* Now check to see if we have a valid ELF file, and one that BFD can |
| make use of. The magic number must match, the address size ('class') |
| and byte-swapping must match our XVEC entry, and it must have a |
| section header table (FIXME: See comments re sections at top of this |
| file). */ |
| if (! elf_file_p (&x_ehdr) |
| || x_ehdr.e_ident[EI_VERSION] != EV_CURRENT |
| || x_ehdr.e_ident[EI_CLASS] != ELFCLASS) |
| goto wrong; |
| |
| /* Check that file's byte order matches xvec's. */ |
| switch (x_ehdr.e_ident[EI_DATA]) |
| { |
| case ELFDATA2MSB: /* Big-endian. */ |
| if (! bfd_header_big_endian (abfd)) |
| goto wrong; |
| break; |
| case ELFDATA2LSB: /* Little-endian. */ |
| if (! bfd_header_little_endian (abfd)) |
| goto wrong; |
| break; |
| case ELFDATANONE: /* No data encoding specified. */ |
| default: /* Unknown data encoding specified . */ |
| goto wrong; |
| } |
| |
| elf_swap_ehdr_in (abfd, &x_ehdr, &i_ehdr); |
| #if DEBUG |
| elf_debug_file (&i_ehdr); |
| #endif |
| |
| if (i_ehdr.e_phentsize != sizeof (Elf_External_Phdr) || i_ehdr.e_phnum == 0) |
| goto fail; |
| |
| /* Read in program headers. */ |
| if (_bfd_mul_overflow (i_ehdr.e_phnum, sizeof (*i_phdr), &amt)) |
| { |
| bfd_set_error (bfd_error_file_too_big); |
| goto fail; |
| } |
| i_phdr = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt); |
| if (i_phdr == NULL) |
| goto fail; |
| |
| if (bfd_seek (abfd, (file_ptr) (offset + i_ehdr.e_phoff), SEEK_SET) != 0) |
| goto fail; |
| |
| /* Read in program headers and parse notes. */ |
| for (i = 0; i < i_ehdr.e_phnum; ++i, ++i_phdr) |
| { |
| Elf_External_Phdr x_phdr; |
| |
| if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) |
| goto fail; |
| elf_swap_phdr_in (abfd, &x_phdr, i_phdr); |
| |
| if (i_phdr->p_type == PT_NOTE && i_phdr->p_filesz > 0) |
| { |
| elf_read_notes (abfd, offset + i_phdr->p_offset, |
| i_phdr->p_filesz, i_phdr->p_align); |
| |
| /* Make sure ABFD returns to processing the program headers. */ |
| if (bfd_seek (abfd, (file_ptr) (offset + i_ehdr.e_phoff |
| + (i + 1) * sizeof (x_phdr)), |
| SEEK_SET) != 0) |
| goto fail; |
| |
| if (abfd->build_id != NULL) |
| return true; |
| } |
| } |
| |
| /* Having gotten this far, we have a valid ELF section, but no |
| build-id was found. */ |
| goto fail; |
| |
| wrong: |
| bfd_set_error (bfd_error_wrong_format); |
| fail: |
| return false; |
| } |