405 lines
10 KiB
C
405 lines
10 KiB
C
/* Generic BFD support for file formats.
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Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2002
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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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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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*/
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#include "bfd.h"
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#include "sysdep.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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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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boolean
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bfd_check_format (abfd, format)
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bfd *abfd;
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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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/*
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FUNCTION
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bfd_check_format_matches
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SYNOPSIS
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boolean bfd_check_format_matches(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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boolean
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bfd_check_format_matches (abfd, format, matching)
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bfd *abfd;
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bfd_format format;
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char ***matching;
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{
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extern const bfd_target binary_vec;
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const bfd_target * const *target, *save_targ, *right_targ, *ar_right_targ;
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char **matching_vector = NULL;
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int match_count;
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int ar_match_index;
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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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/* Since the target type was defaulted, check them
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all in the hope that one will be uniquely recognized. */
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save_targ = abfd->xvec;
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match_count = 0;
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ar_match_index = _bfd_target_vector_entries;
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if (matching)
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{
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bfd_size_type amt;
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*matching = NULL;
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amt = sizeof (char *) * 2 * _bfd_target_vector_entries;
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matching_vector = (char **) bfd_malloc (amt);
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if (!matching_vector)
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return false;
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}
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right_targ = 0;
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ar_right_targ = 0;
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/* Presume the answer is yes. */
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abfd->format = format;
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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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return false;
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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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{
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abfd->xvec = right_targ; /* Set the target as returned. */
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if (matching)
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free (matching_vector);
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return true; /* File position has moved, BTW. */
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}
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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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{
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abfd->xvec = save_targ;
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abfd->format = bfd_unknown;
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if (matching)
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free (matching_vector);
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bfd_set_error (bfd_error_file_not_recognized);
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return false;
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}
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}
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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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bfd_error_type err;
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if (*target == &binary_vec)
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continue;
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abfd->xvec = *target; /* Change BFD's target temporarily */
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if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
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return false;
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/* If _bfd_check_format neglects to set bfd_error, assume
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bfd_error_wrong_format. We didn't used to even pay any
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attention to bfd_error, so I suspect that some
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_bfd_check_format might have this problem. */
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bfd_set_error (bfd_error_wrong_format);
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temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
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if (temp)
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{ /* This format checks out as ok! */
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right_targ = temp;
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/* If this is the default target, accept it, even if other
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targets might match. People who want those other targets
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have to set the GNUTARGET variable. */
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if (temp == bfd_default_vector[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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if (matching)
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matching_vector[match_count] = temp->name;
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match_count++;
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#ifdef GNU960
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/* Big- and little-endian b.out archives look the same, but it
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doesn't matter: there is no difference in their headers, and
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member file byte orders will (I hope) be handled appropriately
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by bfd. Ditto for big and little coff archives. And the 4
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coff/b.out object formats are unambiguous. So accept the
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first match we find. */
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break;
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#endif
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}
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else if ((err = bfd_get_error ()) == bfd_error_wrong_object_format
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|| err == bfd_error_file_ambiguously_recognized)
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{
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/* An archive with objects of the wrong type, or an
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ambiguous match. We want this target to match if we get
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no 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)
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matching_vector[ar_match_index] = (*target)->name;
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ar_match_index++;
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}
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else if (err != bfd_error_wrong_format)
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{
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abfd->xvec = save_targ;
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abfd->format = bfd_unknown;
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if (matching)
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free (matching_vector);
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return false;
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}
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}
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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 && match_count > 1)
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{
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memcpy (matching_vector,
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matching_vector + _bfd_target_vector_entries,
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sizeof (char *) * match_count);
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}
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}
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}
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if (match_count == 1)
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{
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abfd->xvec = right_targ; /* Change BFD's target permanently. */
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if (matching)
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free (matching_vector);
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return true; /* File position has moved, BTW. */
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}
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abfd->xvec = save_targ; /* Restore original target type. */
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abfd->format = bfd_unknown; /* Restore original format. */
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if (match_count == 0)
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{
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bfd_set_error (bfd_error_file_not_recognized);
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if (matching)
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free (matching_vector);
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}
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else
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{
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bfd_set_error (bfd_error_file_ambiguously_recognized);
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if (matching)
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{
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*matching = matching_vector;
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matching_vector[match_count] = NULL;
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}
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}
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return false;
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}
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/*
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FUNCTION
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bfd_set_format
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SYNOPSIS
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boolean bfd_set_format(bfd *abfd, bfd_format format);
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DESCRIPTION
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This function sets the file format of the BFD @var{abfd} to the
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format @var{format}. If the target set in the BFD does not
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support the format requested, the format is invalid, or the BFD
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is not open for writing, then an error occurs.
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*/
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boolean
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bfd_set_format (abfd, format)
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bfd *abfd;
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bfd_format format;
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{
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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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/* Presume the answer is yes. */
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abfd->format = format;
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if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd)))
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{
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abfd->format = bfd_unknown;
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return false;
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}
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return true;
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}
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/*
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FUNCTION
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bfd_format_string
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SYNOPSIS
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const char *bfd_format_string(bfd_format format);
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DESCRIPTION
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Return a pointer to a const string
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<<invalid>>, <<object>>, <<archive>>, <<core>>, or <<unknown>>,
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depending upon the value of @var{format}.
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*/
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const char *
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bfd_format_string (format)
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bfd_format format;
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{
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if (((int)format <(int) bfd_unknown)
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|| ((int)format >=(int) bfd_type_end))
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return "invalid";
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switch (format)
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{
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case bfd_object:
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return "object"; /* Linker/assember/compiler output. */
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case bfd_archive:
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return "archive"; /* Object archive file. */
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case bfd_core:
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return "core"; /* Core dump. */
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default:
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return "unknown";
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}
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}
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