342 lines
10 KiB
C
342 lines
10 KiB
C
/* ELF core file support for BFD.
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Copyright 1995, 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2005, 2007,
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2008, 2010 Free Software Foundation, Inc.
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This file is part of BFD, the Binary File Descriptor library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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MA 02110-1301, USA. */
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char*
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elf_core_file_failing_command (bfd *abfd)
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{
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return elf_tdata (abfd)->core_command;
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}
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int
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elf_core_file_failing_signal (bfd *abfd)
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{
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return elf_tdata (abfd)->core_signal;
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}
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int
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elf_core_file_pid (bfd *abfd)
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{
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return elf_tdata (abfd)->core_pid;
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}
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bfd_boolean
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elf_core_file_matches_executable_p (bfd *core_bfd, bfd *exec_bfd)
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{
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char* corename;
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/* xvecs must match if both are ELF files for the same target. */
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if (core_bfd->xvec != exec_bfd->xvec)
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{
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bfd_set_error (bfd_error_system_call);
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return FALSE;
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}
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/* See if the name in the corefile matches the executable name. */
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corename = elf_tdata (core_bfd)->core_program;
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if (corename != NULL)
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{
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const char* execname = strrchr (exec_bfd->filename, '/');
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execname = execname ? execname + 1 : exec_bfd->filename;
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if (strcmp (execname, corename) != 0)
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return FALSE;
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}
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return TRUE;
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}
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/* Core files are simply standard ELF formatted files that partition
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the file using the execution view of the file (program header table)
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rather than the linking view. In fact, there is no section header
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table in a core file.
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The process status information (including the contents of the general
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register set) and the floating point register set are stored in a
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segment of type PT_NOTE. We handcraft a couple of extra bfd sections
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that allow standard bfd access to the general registers (.reg) and the
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floating point registers (.reg2). */
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const bfd_target *
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elf_core_file_p (bfd *abfd)
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{
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Elf_External_Ehdr x_ehdr; /* Elf file header, external form. */
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Elf_Internal_Ehdr *i_ehdrp; /* Elf file header, internal form. */
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Elf_Internal_Phdr *i_phdrp; /* Elf program header, internal form. */
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unsigned int phindex;
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const struct elf_backend_data *ebd;
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struct bfd_preserve preserve;
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bfd_size_type amt;
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preserve.marker = NULL;
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/* Read in the ELF header in external format. */
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if (bfd_bread (&x_ehdr, sizeof (x_ehdr), abfd) != sizeof (x_ehdr))
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{
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if (bfd_get_error () != bfd_error_system_call)
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goto wrong;
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else
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goto fail;
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}
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/* Check the magic number. */
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if (! elf_file_p (&x_ehdr))
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goto wrong;
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/* FIXME: Check EI_VERSION here ! */
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/* Check the address size ("class"). */
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if (x_ehdr.e_ident[EI_CLASS] != ELFCLASS)
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goto wrong;
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/* Check the byteorder. */
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switch (x_ehdr.e_ident[EI_DATA])
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{
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case ELFDATA2MSB: /* Big-endian. */
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if (! bfd_big_endian (abfd))
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goto wrong;
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break;
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case ELFDATA2LSB: /* Little-endian. */
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if (! bfd_little_endian (abfd))
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goto wrong;
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break;
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default:
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goto wrong;
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}
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if (!bfd_preserve_save (abfd, &preserve))
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goto fail;
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/* Give abfd an elf_obj_tdata. */
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if (! (*abfd->xvec->_bfd_set_format[bfd_core]) (abfd))
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goto fail;
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preserve.marker = elf_tdata (abfd);
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/* Swap in the rest of the header, now that we have the byte order. */
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i_ehdrp = elf_elfheader (abfd);
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elf_swap_ehdr_in (abfd, &x_ehdr, i_ehdrp);
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#if DEBUG & 1
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elf_debug_file (i_ehdrp);
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#endif
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ebd = get_elf_backend_data (abfd);
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/* Check that the ELF e_machine field matches what this particular
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BFD format expects. */
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if (ebd->elf_machine_code != i_ehdrp->e_machine
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&& (ebd->elf_machine_alt1 == 0
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|| i_ehdrp->e_machine != ebd->elf_machine_alt1)
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&& (ebd->elf_machine_alt2 == 0
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|| i_ehdrp->e_machine != ebd->elf_machine_alt2))
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{
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const bfd_target * const *target_ptr;
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if (ebd->elf_machine_code != EM_NONE)
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goto wrong;
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/* This is the generic ELF target. Let it match any ELF target
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for which we do not have a specific backend. */
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for (target_ptr = bfd_target_vector; *target_ptr != NULL; target_ptr++)
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{
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const struct elf_backend_data *back;
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if ((*target_ptr)->flavour != bfd_target_elf_flavour)
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continue;
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back = xvec_get_elf_backend_data (*target_ptr);
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if (back->s->arch_size != ARCH_SIZE)
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continue;
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if (back->elf_machine_code == i_ehdrp->e_machine
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|| (back->elf_machine_alt1 != 0
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&& i_ehdrp->e_machine == back->elf_machine_alt1)
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|| (back->elf_machine_alt2 != 0
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&& i_ehdrp->e_machine == back->elf_machine_alt2))
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{
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/* target_ptr is an ELF backend which matches this
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object file, so reject the generic ELF target. */
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goto wrong;
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}
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}
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}
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/* If there is no program header, or the type is not a core file, then
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we are hosed. */
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if (i_ehdrp->e_phoff == 0 || i_ehdrp->e_type != ET_CORE)
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goto wrong;
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/* Does BFD's idea of the phdr size match the size
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recorded in the file? */
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if (i_ehdrp->e_phentsize != sizeof (Elf_External_Phdr))
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goto wrong;
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/* If the program header count is PN_XNUM(0xffff), the actual
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count is in the first section header. */
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if (i_ehdrp->e_shoff != 0 && i_ehdrp->e_phnum == PN_XNUM)
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{
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Elf_External_Shdr x_shdr;
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Elf_Internal_Shdr i_shdr;
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bfd_signed_vma where = i_ehdrp->e_shoff;
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if (where != (file_ptr) where)
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goto wrong;
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/* Seek to the section header table in the file. */
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if (bfd_seek (abfd, (file_ptr) where, SEEK_SET) != 0)
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goto fail;
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/* Read the first section header at index 0, and convert to internal
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form. */
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if (bfd_bread (&x_shdr, sizeof (x_shdr), abfd) != sizeof (x_shdr))
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goto fail;
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elf_swap_shdr_in (abfd, &x_shdr, &i_shdr);
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if (i_shdr.sh_info != 0)
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{
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i_ehdrp->e_phnum = i_shdr.sh_info;
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if (i_ehdrp->e_phnum != i_shdr.sh_info)
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goto wrong;
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}
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}
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/* Sanity check that we can read all of the program headers.
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It ought to be good enough to just read the last one. */
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if (i_ehdrp->e_phnum > 1)
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{
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Elf_External_Phdr x_phdr;
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Elf_Internal_Phdr i_phdr;
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bfd_signed_vma where;
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/* Check that we don't have a totally silly number of
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program headers. */
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if (i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (x_phdr)
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|| i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (i_phdr))
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goto wrong;
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where = i_ehdrp->e_phoff + (i_ehdrp->e_phnum - 1) * sizeof (x_phdr);
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if (where != (file_ptr) where)
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goto wrong;
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if ((bfd_size_type) where <= i_ehdrp->e_phoff)
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goto wrong;
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if (bfd_seek (abfd, (file_ptr) where, SEEK_SET) != 0)
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goto fail;
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if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr))
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goto fail;
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}
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/* Move to the start of the program headers. */
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if (bfd_seek (abfd, (file_ptr) i_ehdrp->e_phoff, SEEK_SET) != 0)
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goto wrong;
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/* Allocate space for the program headers. */
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amt = sizeof (*i_phdrp) * i_ehdrp->e_phnum;
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i_phdrp = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt);
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if (!i_phdrp)
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goto fail;
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elf_tdata (abfd)->phdr = i_phdrp;
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/* Read and convert to internal form. */
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for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex)
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{
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Elf_External_Phdr x_phdr;
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if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr))
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goto fail;
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elf_swap_phdr_in (abfd, &x_phdr, i_phdrp + phindex);
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}
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/* Set the machine architecture. Do this before processing the
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program headers since we need to know the architecture type
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when processing the notes of some systems' core files. */
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if (! bfd_default_set_arch_mach (abfd, ebd->arch, 0)
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/* It's OK if this fails for the generic target. */
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&& ebd->elf_machine_code != EM_NONE)
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goto fail;
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/* Let the backend double check the format and override global
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information. We do this before processing the program headers
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to allow the correct machine (as opposed to just the default
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machine) to be set, making it possible for grok_prstatus and
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grok_psinfo to rely on the mach setting. */
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if (ebd->elf_backend_object_p != NULL
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&& ! ebd->elf_backend_object_p (abfd))
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goto wrong;
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/* Process each program header. */
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for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex)
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if (! bfd_section_from_phdr (abfd, i_phdrp + phindex, (int) phindex))
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goto fail;
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/* Check for core truncation. */
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{
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bfd_size_type high = 0;
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struct stat statbuf;
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for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex)
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{
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Elf_Internal_Phdr *p = i_phdrp + phindex;
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if (p->p_filesz)
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{
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bfd_size_type current = p->p_offset + p->p_filesz;
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if (high < current)
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high = current;
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}
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}
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if (bfd_stat (abfd, &statbuf) == 0)
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{
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if ((bfd_size_type) statbuf.st_size < high)
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{
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(*_bfd_error_handler)
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(_("Warning: %B is truncated: expected core file "
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"size >= %lu, found: %lu."),
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abfd, (unsigned long) high, (unsigned long) statbuf.st_size);
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}
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}
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}
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/* Save the entry point from the ELF header. */
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bfd_get_start_address (abfd) = i_ehdrp->e_entry;
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bfd_preserve_finish (abfd, &preserve);
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return abfd->xvec;
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wrong:
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/* There is way too much undoing of half-known state here. The caller,
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bfd_check_format_matches, really shouldn't iterate on live bfd's to
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check match/no-match like it does. We have to rely on that a call to
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bfd_default_set_arch_mach with the previously known mach, undoes what
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was done by the first bfd_default_set_arch_mach (with mach 0) here.
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For this to work, only elf-data and the mach may be changed by the
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target-specific elf_backend_object_p function. Note that saving the
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whole bfd here and restoring it would be even worse; the first thing
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you notice is that the cached bfd file position gets out of sync. */
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bfd_set_error (bfd_error_wrong_format);
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fail:
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if (preserve.marker != NULL)
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bfd_preserve_restore (abfd, &preserve);
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return NULL;
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}
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