49078ece04
Since 1993-11-05 git commit c188b0bec3
, bfd_check_format has failed
if any of the target object_p functions returns false with any error
but bfd_error_wrong_format. That's just weird. There is really no
reason why coff_real_object_p should be fixed to only return that
error instead of numerous other possible errors. Even an out of
memory condition for one target doesn't necessarily mean other targets
can't match, assuming the failing target nicely returns all memory it
might have used.
* format.c (bfd_check_format_matches): Ignore bfd_error on target
match failures. Don't init to bfd_error_wrong_format before
calling _bfd_check_format.
608 lines
17 KiB
C
608 lines
17 KiB
C
/* Generic BFD support for file formats.
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Copyright (C) 1990-2020 Free Software Foundation, Inc.
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Written by Cygnus Support.
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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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/*
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SECTION
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File formats
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A format is a BFD concept of high level file contents type. The
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formats supported by BFD are:
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o <<bfd_object>>
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The BFD may contain data, symbols, relocations and debug info.
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o <<bfd_archive>>
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The BFD contains other BFDs and an optional index.
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o <<bfd_core>>
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The BFD contains the result of an executable core dump.
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SUBSECTION
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File format functions
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*/
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#include "sysdep.h"
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#include "bfd.h"
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#include "libbfd.h"
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/* IMPORT from targets.c. */
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extern const size_t _bfd_target_vector_entries;
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/*
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FUNCTION
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bfd_check_format
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SYNOPSIS
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bfd_boolean bfd_check_format (bfd *abfd, bfd_format format);
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DESCRIPTION
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Verify if the file attached to the BFD @var{abfd} is compatible
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with the format @var{format} (i.e., one of <<bfd_object>>,
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<<bfd_archive>> or <<bfd_core>>).
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If the BFD has been set to a specific target before the
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call, only the named target and format combination is
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checked. If the target has not been set, or has been set to
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<<default>>, then all the known target backends is
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interrogated to determine a match. If the default target
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matches, it is used. If not, exactly one target must recognize
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the file, or an error results.
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The function returns <<TRUE>> on success, otherwise <<FALSE>>
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with one of the following error codes:
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o <<bfd_error_invalid_operation>> -
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if <<format>> is not one of <<bfd_object>>, <<bfd_archive>> or
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<<bfd_core>>.
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o <<bfd_error_system_call>> -
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if an error occured during a read - even some file mismatches
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can cause bfd_error_system_calls.
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o <<file_not_recognised>> -
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none of the backends recognised the file format.
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o <<bfd_error_file_ambiguously_recognized>> -
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more than one backend recognised the file format.
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*/
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bfd_boolean
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bfd_check_format (bfd *abfd, bfd_format format)
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{
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return bfd_check_format_matches (abfd, format, NULL);
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}
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struct bfd_preserve
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{
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void *marker;
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void *tdata;
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flagword flags;
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const struct bfd_arch_info *arch_info;
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struct bfd_section *sections;
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struct bfd_section *section_last;
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unsigned int section_count;
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unsigned int section_id;
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struct bfd_hash_table section_htab;
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const struct bfd_build_id *build_id;
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};
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/* When testing an object for compatibility with a particular target
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back-end, the back-end object_p function needs to set up certain
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fields in the bfd on successfully recognizing the object. This
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typically happens in a piecemeal fashion, with failures possible at
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many points. On failure, the bfd is supposed to be restored to its
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initial state, which is virtually impossible. However, restoring a
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subset of the bfd state works in practice. This function stores
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the subset. */
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static bfd_boolean
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bfd_preserve_save (bfd *abfd, struct bfd_preserve *preserve)
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{
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preserve->tdata = abfd->tdata.any;
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preserve->arch_info = abfd->arch_info;
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preserve->flags = abfd->flags;
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preserve->sections = abfd->sections;
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preserve->section_last = abfd->section_last;
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preserve->section_count = abfd->section_count;
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preserve->section_id = _bfd_section_id;
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preserve->section_htab = abfd->section_htab;
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preserve->marker = bfd_alloc (abfd, 1);
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preserve->build_id = abfd->build_id;
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if (preserve->marker == NULL)
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return FALSE;
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return bfd_hash_table_init (&abfd->section_htab, bfd_section_hash_newfunc,
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sizeof (struct section_hash_entry));
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}
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/* Clear out a subset of BFD state. */
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static void
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bfd_reinit (bfd *abfd, unsigned int section_id)
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{
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abfd->tdata.any = NULL;
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abfd->arch_info = &bfd_default_arch_struct;
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abfd->flags &= BFD_FLAGS_SAVED;
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bfd_section_list_clear (abfd);
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_bfd_section_id = section_id;
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}
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/* Restores bfd state saved by bfd_preserve_save. */
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static void
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bfd_preserve_restore (bfd *abfd, struct bfd_preserve *preserve)
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{
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bfd_hash_table_free (&abfd->section_htab);
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abfd->tdata.any = preserve->tdata;
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abfd->arch_info = preserve->arch_info;
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abfd->flags = preserve->flags;
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abfd->section_htab = preserve->section_htab;
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abfd->sections = preserve->sections;
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abfd->section_last = preserve->section_last;
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abfd->section_count = preserve->section_count;
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_bfd_section_id = preserve->section_id;
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abfd->build_id = preserve->build_id;
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/* bfd_release frees all memory more recently bfd_alloc'd than
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its arg, as well as its arg. */
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bfd_release (abfd, preserve->marker);
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preserve->marker = NULL;
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}
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/* Called when the bfd state saved by bfd_preserve_save is no longer
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needed. */
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static void
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bfd_preserve_finish (bfd *abfd ATTRIBUTE_UNUSED, struct bfd_preserve *preserve)
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{
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/* It would be nice to be able to free more memory here, eg. old
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tdata, but that's not possible since these blocks are sitting
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inside bfd_alloc'd memory. The section hash is on a separate
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objalloc. */
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bfd_hash_table_free (&preserve->section_htab);
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preserve->marker = NULL;
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}
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/*
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FUNCTION
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bfd_check_format_matches
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SYNOPSIS
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bfd_boolean bfd_check_format_matches
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(bfd *abfd, bfd_format format, char ***matching);
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DESCRIPTION
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Like <<bfd_check_format>>, except when it returns FALSE with
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<<bfd_errno>> set to <<bfd_error_file_ambiguously_recognized>>. In that
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case, if @var{matching} is not NULL, it will be filled in with
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a NULL-terminated list of the names of the formats that matched,
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allocated with <<malloc>>.
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Then the user may choose a format and try again.
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When done with the list that @var{matching} points to, the caller
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should free it.
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*/
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bfd_boolean
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bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
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{
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extern const bfd_target binary_vec;
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#if BFD_SUPPORTS_PLUGINS
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extern const bfd_target plugin_vec;
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#endif
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const bfd_target * const *target;
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const bfd_target **matching_vector = NULL;
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const bfd_target *save_targ, *right_targ, *ar_right_targ, *match_targ;
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int match_count, best_count, best_match;
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int ar_match_index;
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unsigned int initial_section_id = _bfd_section_id;
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struct bfd_preserve preserve, preserve_match;
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if (matching != NULL)
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*matching = NULL;
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if (!bfd_read_p (abfd)
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|| (unsigned int) abfd->format >= (unsigned int) bfd_type_end)
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{
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bfd_set_error (bfd_error_invalid_operation);
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return FALSE;
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}
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if (abfd->format != bfd_unknown)
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return abfd->format == format;
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if (matching != NULL || *bfd_associated_vector != NULL)
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{
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bfd_size_type amt;
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amt = sizeof (*matching_vector) * 2 * _bfd_target_vector_entries;
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matching_vector = (const bfd_target **) bfd_malloc (amt);
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if (!matching_vector)
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return FALSE;
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}
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/* Presume the answer is yes. */
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abfd->format = format;
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save_targ = abfd->xvec;
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preserve_match.marker = NULL;
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if (!bfd_preserve_save (abfd, &preserve))
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goto err_ret;
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/* If the target type was explicitly specified, just check that target. */
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if (!abfd->target_defaulted)
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{
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if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0) /* rewind! */
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goto err_ret;
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right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
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if (right_targ)
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goto ok_ret;
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/* For a long time the code has dropped through to check all
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targets if the specified target was wrong. I don't know why,
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and I'm reluctant to change it. However, in the case of an
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archive, it can cause problems. If the specified target does
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not permit archives (e.g., the binary target), then we should
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not allow some other target to recognize it as an archive, but
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should instead allow the specified target to recognize it as an
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object. When I first made this change, it broke the PE target,
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because the specified pei-i386 target did not recognize the
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actual pe-i386 archive. Since there may be other problems of
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this sort, I changed this test to check only for the binary
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target. */
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if (format == bfd_archive && save_targ == &binary_vec)
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goto err_unrecog;
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}
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/* Since the target type was defaulted, check them all in the hope
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that one will be uniquely recognized. */
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right_targ = NULL;
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ar_right_targ = NULL;
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match_targ = NULL;
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best_match = 256;
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best_count = 0;
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match_count = 0;
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ar_match_index = _bfd_target_vector_entries;
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for (target = bfd_target_vector; *target != NULL; target++)
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{
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const bfd_target *temp;
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void **high_water;
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/* The binary target matches anything, so don't return it when
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searching. Don't match the plugin target if we have another
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alternative since we want to properly set the input format
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before allowing a plugin to claim the file. Also, don't
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check the default target twice. */
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if (*target == &binary_vec
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#if BFD_SUPPORTS_PLUGINS
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|| (match_count != 0 && *target == &plugin_vec)
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#endif
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|| (!abfd->target_defaulted && *target == save_targ))
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continue;
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/* If we already tried a match, the bfd is modified and may
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have sections attached, which will confuse the next
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_bfd_check_format call. */
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bfd_reinit (abfd, initial_section_id);
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/* Free bfd_alloc memory too. If we have matched and preserved
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a target then the high water mark is that much higher. */
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if (preserve_match.marker)
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high_water = &preserve_match.marker;
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else
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high_water = &preserve.marker;
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bfd_release (abfd, *high_water);
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*high_water = bfd_alloc (abfd, 1);
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/* Change BFD's target temporarily. */
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abfd->xvec = *target;
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if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
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goto err_ret;
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temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
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if (temp)
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{
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int match_priority = temp->match_priority;
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#if BFD_SUPPORTS_PLUGINS
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/* If this object can be handled by a plugin, give that the
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lowest priority; objects both handled by a plugin and
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with an underlying object format will be claimed
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separately by the plugin. */
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if (*target == &plugin_vec)
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match_priority = (*target)->match_priority;
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#endif
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if (abfd->format != bfd_archive
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|| (bfd_has_map (abfd)
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&& bfd_get_error () != bfd_error_wrong_object_format))
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{
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/* If this is the default target, accept it, even if
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other targets might match. People who want those
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other targets have to set the GNUTARGET variable. */
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if (temp == bfd_default_vector[0])
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goto ok_ret;
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if (matching_vector)
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matching_vector[match_count] = temp;
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match_count++;
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if (match_priority < best_match)
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{
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best_match = match_priority;
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best_count = 0;
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}
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if (match_priority <= best_match)
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{
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/* This format checks out as ok! */
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right_targ = temp;
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best_count++;
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}
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}
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else
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{
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/* An archive with no armap or objects of the wrong
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type. We want this target to match if we get no
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better matches. */
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if (ar_right_targ != bfd_default_vector[0])
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ar_right_targ = *target;
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if (matching_vector)
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matching_vector[ar_match_index] = *target;
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ar_match_index++;
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}
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if (preserve_match.marker == NULL)
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{
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match_targ = temp;
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if (!bfd_preserve_save (abfd, &preserve_match))
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goto err_ret;
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}
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}
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}
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if (best_count == 1)
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match_count = 1;
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if (match_count == 0)
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{
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/* Try partial matches. */
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right_targ = ar_right_targ;
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if (right_targ == bfd_default_vector[0])
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{
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match_count = 1;
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}
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else
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{
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match_count = ar_match_index - _bfd_target_vector_entries;
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if (matching_vector && match_count > 1)
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memcpy (matching_vector,
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matching_vector + _bfd_target_vector_entries,
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sizeof (*matching_vector) * match_count);
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}
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}
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/* We have more than one equally good match. If any of the best
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matches is a target in config.bfd targ_defvec or targ_selvecs,
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choose it. */
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if (match_count > 1)
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{
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const bfd_target * const *assoc = bfd_associated_vector;
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while ((right_targ = *assoc++) != NULL)
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{
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int i = match_count;
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while (--i >= 0)
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if (matching_vector[i] == right_targ
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&& right_targ->match_priority <= best_match)
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break;
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if (i >= 0)
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{
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match_count = 1;
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break;
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}
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}
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}
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/* We still have more than one equally good match, and at least some
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of the targets support match priority. Choose the first of the
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best matches. */
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if (matching_vector && match_count > 1 && best_count != match_count)
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{
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int i;
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for (i = 0; i < match_count; i++)
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{
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right_targ = matching_vector[i];
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if (right_targ->match_priority <= best_match)
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break;
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}
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match_count = 1;
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}
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/* There is way too much undoing of half-known state here. We
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really shouldn't iterate on live bfd's. Note that saving the
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whole bfd 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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if (preserve_match.marker != NULL)
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bfd_preserve_restore (abfd, &preserve_match);
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if (match_count == 1)
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{
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abfd->xvec = right_targ;
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/* If we come out of the loop knowing that the last target that
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matched is the one we want, then ABFD should still be in a usable
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state (except possibly for XVEC). This is not just an
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optimisation. In the case of plugins a match against the
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plugin target can result in the bfd being changed such that
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it no longer matches the plugin target, nor will it match
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RIGHT_TARG again. */
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if (match_targ != right_targ)
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{
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bfd_reinit (abfd, initial_section_id);
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bfd_release (abfd, preserve.marker);
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if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
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goto err_ret;
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match_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
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BFD_ASSERT (match_targ != NULL);
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}
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ok_ret:
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/* If the file was opened for update, then `output_has_begun'
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some time ago when the file was created. Do not recompute
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sections sizes or alignments in _bfd_set_section_contents.
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We can not set this flag until after checking the format,
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because it will interfere with creation of BFD sections. */
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if (abfd->direction == both_direction)
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abfd->output_has_begun = TRUE;
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if (matching_vector)
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free (matching_vector);
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if (preserve_match.marker != NULL)
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bfd_preserve_finish (abfd, &preserve_match);
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bfd_preserve_finish (abfd, &preserve);
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/* File position has moved, BTW. */
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return TRUE;
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}
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if (match_count == 0)
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{
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err_unrecog:
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bfd_set_error (bfd_error_file_not_recognized);
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err_ret:
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abfd->xvec = save_targ;
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abfd->format = bfd_unknown;
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if (matching_vector)
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free (matching_vector);
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if (preserve_match.marker != NULL)
|
|
bfd_preserve_finish (abfd, &preserve_match);
|
|
bfd_preserve_restore (abfd, &preserve);
|
|
return FALSE;
|
|
}
|
|
|
|
/* Restore original target type and format. */
|
|
abfd->xvec = save_targ;
|
|
abfd->format = bfd_unknown;
|
|
bfd_set_error (bfd_error_file_ambiguously_recognized);
|
|
|
|
if (matching)
|
|
{
|
|
*matching = (char **) matching_vector;
|
|
matching_vector[match_count] = NULL;
|
|
/* Return target names. This is a little nasty. Maybe we
|
|
should do another bfd_malloc? */
|
|
while (--match_count >= 0)
|
|
{
|
|
const char *name = matching_vector[match_count]->name;
|
|
*(const char **) &matching_vector[match_count] = name;
|
|
}
|
|
}
|
|
else if (matching_vector)
|
|
free (matching_vector);
|
|
if (preserve_match.marker != NULL)
|
|
bfd_preserve_finish (abfd, &preserve_match);
|
|
bfd_preserve_restore (abfd, &preserve);
|
|
return FALSE;
|
|
}
|
|
|
|
/*
|
|
FUNCTION
|
|
bfd_set_format
|
|
|
|
SYNOPSIS
|
|
bfd_boolean bfd_set_format (bfd *abfd, bfd_format format);
|
|
|
|
DESCRIPTION
|
|
This function sets the file format of the BFD @var{abfd} to the
|
|
format @var{format}. If the target set in the BFD does not
|
|
support the format requested, the format is invalid, or the BFD
|
|
is not open for writing, then an error occurs.
|
|
*/
|
|
|
|
bfd_boolean
|
|
bfd_set_format (bfd *abfd, bfd_format format)
|
|
{
|
|
if (bfd_read_p (abfd)
|
|
|| (unsigned int) abfd->format >= (unsigned int) bfd_type_end)
|
|
{
|
|
bfd_set_error (bfd_error_invalid_operation);
|
|
return FALSE;
|
|
}
|
|
|
|
if (abfd->format != bfd_unknown)
|
|
return abfd->format == format;
|
|
|
|
/* Presume the answer is yes. */
|
|
abfd->format = format;
|
|
|
|
if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd)))
|
|
{
|
|
abfd->format = bfd_unknown;
|
|
return FALSE;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
/*
|
|
FUNCTION
|
|
bfd_format_string
|
|
|
|
SYNOPSIS
|
|
const char *bfd_format_string (bfd_format format);
|
|
|
|
DESCRIPTION
|
|
Return a pointer to a const string
|
|
<<invalid>>, <<object>>, <<archive>>, <<core>>, or <<unknown>>,
|
|
depending upon the value of @var{format}.
|
|
*/
|
|
|
|
const char *
|
|
bfd_format_string (bfd_format format)
|
|
{
|
|
if (((int) format < (int) bfd_unknown)
|
|
|| ((int) format >= (int) bfd_type_end))
|
|
return "invalid";
|
|
|
|
switch (format)
|
|
{
|
|
case bfd_object:
|
|
return "object"; /* Linker/assembler/compiler output. */
|
|
case bfd_archive:
|
|
return "archive"; /* Object archive file. */
|
|
case bfd_core:
|
|
return "core"; /* Core dump. */
|
|
default:
|
|
return "unknown";
|
|
}
|
|
}
|