/* Generic BFD support for file formats.
- Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2002,
- 2003, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
+ Copyright (C) 1990-2020 Free Software Foundation, Inc.
Written by Cygnus Support.
This file is part of BFD, the Binary File Descriptor library.
return bfd_check_format_matches (abfd, format, NULL);
}
+struct bfd_preserve
+{
+ void *marker;
+ void *tdata;
+ flagword flags;
+ const struct bfd_arch_info *arch_info;
+ struct bfd_section *sections;
+ struct bfd_section *section_last;
+ unsigned int section_count;
+ unsigned int section_id;
+ struct bfd_hash_table section_htab;
+ const struct bfd_build_id *build_id;
+};
+
+/* When testing an object for compatibility with a particular target
+ back-end, the back-end object_p function needs to set up certain
+ fields in the bfd on successfully recognizing the object. This
+ typically happens in a piecemeal fashion, with failures possible at
+ many points. On failure, the bfd is supposed to be restored to its
+ initial state, which is virtually impossible. However, restoring a
+ subset of the bfd state works in practice. This function stores
+ the subset. */
+
+static bfd_boolean
+bfd_preserve_save (bfd *abfd, struct bfd_preserve *preserve)
+{
+ preserve->tdata = abfd->tdata.any;
+ preserve->arch_info = abfd->arch_info;
+ preserve->flags = abfd->flags;
+ preserve->sections = abfd->sections;
+ preserve->section_last = abfd->section_last;
+ preserve->section_count = abfd->section_count;
+ preserve->section_id = _bfd_section_id;
+ preserve->section_htab = abfd->section_htab;
+ preserve->marker = bfd_alloc (abfd, 1);
+ preserve->build_id = abfd->build_id;
+ if (preserve->marker == NULL)
+ return FALSE;
+
+ return bfd_hash_table_init (&abfd->section_htab, bfd_section_hash_newfunc,
+ sizeof (struct section_hash_entry));
+}
+
+/* Clear out a subset of BFD state. */
+
+static void
+bfd_reinit (bfd *abfd, unsigned int section_id)
+{
+ abfd->tdata.any = NULL;
+ abfd->arch_info = &bfd_default_arch_struct;
+ abfd->flags &= BFD_FLAGS_SAVED;
+ bfd_section_list_clear (abfd);
+ _bfd_section_id = section_id;
+}
+
+/* Restores bfd state saved by bfd_preserve_save. */
+
+static void
+bfd_preserve_restore (bfd *abfd, struct bfd_preserve *preserve)
+{
+ bfd_hash_table_free (&abfd->section_htab);
+
+ abfd->tdata.any = preserve->tdata;
+ abfd->arch_info = preserve->arch_info;
+ abfd->flags = preserve->flags;
+ abfd->section_htab = preserve->section_htab;
+ abfd->sections = preserve->sections;
+ abfd->section_last = preserve->section_last;
+ abfd->section_count = preserve->section_count;
+ _bfd_section_id = preserve->section_id;
+ abfd->build_id = preserve->build_id;
+
+ /* bfd_release frees all memory more recently bfd_alloc'd than
+ its arg, as well as its arg. */
+ bfd_release (abfd, preserve->marker);
+ preserve->marker = NULL;
+}
+
+/* Called when the bfd state saved by bfd_preserve_save is no longer
+ needed. */
+
+static void
+bfd_preserve_finish (bfd *abfd ATTRIBUTE_UNUSED, struct bfd_preserve *preserve)
+{
+ /* It would be nice to be able to free more memory here, eg. old
+ tdata, but that's not possible since these blocks are sitting
+ inside bfd_alloc'd memory. The section hash is on a separate
+ objalloc. */
+ bfd_hash_table_free (&preserve->section_htab);
+ preserve->marker = NULL;
+}
+
/*
FUNCTION
bfd_check_format_matches
bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
{
extern const bfd_target binary_vec;
+#if BFD_SUPPORTS_PLUGINS
+ extern const bfd_target plugin_vec;
+#endif
const bfd_target * const *target;
const bfd_target **matching_vector = NULL;
const bfd_target *save_targ, *right_targ, *ar_right_targ, *match_targ;
int match_count, best_count, best_match;
int ar_match_index;
+ unsigned int initial_section_id = _bfd_section_id;
+ struct bfd_preserve preserve, preserve_match;
if (matching != NULL)
*matching = NULL;
if (abfd->format != bfd_unknown)
return abfd->format == format;
- /* Since the target type was defaulted, check them
- all in the hope that one will be uniquely recognized. */
- save_targ = abfd->xvec;
- match_count = 0;
- ar_match_index = _bfd_target_vector_entries;
-
if (matching != NULL || *bfd_associated_vector != NULL)
{
bfd_size_type amt;
return FALSE;
}
- right_targ = 0;
- ar_right_targ = 0;
- match_targ = 0;
- best_match = 256;
- best_count = 0;
-
/* Presume the answer is yes. */
abfd->format = format;
+ save_targ = abfd->xvec;
+
+ preserve_match.marker = NULL;
+ if (!bfd_preserve_save (abfd, &preserve))
+ goto err_ret;
/* If the target type was explicitly specified, just check that target. */
if (!abfd->target_defaulted)
goto err_unrecog;
}
+ /* Since the target type was defaulted, check them all in the hope
+ that one will be uniquely recognized. */
+ right_targ = NULL;
+ ar_right_targ = NULL;
+ match_targ = NULL;
+ best_match = 256;
+ best_count = 0;
+ match_count = 0;
+ ar_match_index = _bfd_target_vector_entries;
+
for (target = bfd_target_vector; *target != NULL; target++)
{
const bfd_target *temp;
- bfd_error_type err;
+ void **high_water;
- /* Don't check the default target twice. */
+ /* The binary target matches anything, so don't return it when
+ searching. Don't match the plugin target if we have another
+ alternative since we want to properly set the input format
+ before allowing a plugin to claim the file. Also, don't
+ check the default target twice. */
if (*target == &binary_vec
- || (!abfd->target_defaulted && *target == save_targ)
- || (*target)->match_priority > best_match)
+#if BFD_SUPPORTS_PLUGINS
+ || (match_count != 0 && *target == &plugin_vec)
+#endif
+ || (!abfd->target_defaulted && *target == save_targ))
continue;
- abfd->xvec = *target; /* Change BFD's target temporarily. */
+ /* If we already tried a match, the bfd is modified and may
+ have sections attached, which will confuse the next
+ _bfd_check_format call. */
+ bfd_reinit (abfd, initial_section_id);
+ /* Free bfd_alloc memory too. If we have matched and preserved
+ a target then the high water mark is that much higher. */
+ if (preserve_match.marker)
+ high_water = &preserve_match.marker;
+ else
+ high_water = &preserve.marker;
+ bfd_release (abfd, *high_water);
+ *high_water = bfd_alloc (abfd, 1);
+
+ /* Change BFD's target temporarily. */
+ abfd->xvec = *target;
if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
goto err_ret;
- /* If _bfd_check_format neglects to set bfd_error, assume
- bfd_error_wrong_format. We didn't used to even pay any
- attention to bfd_error, so I suspect that some
- _bfd_check_format might have this problem. */
- bfd_set_error (bfd_error_wrong_format);
-
temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
if (temp)
- match_targ = temp;
-
- if (temp && (abfd->format != bfd_archive || bfd_has_map (abfd)))
{
- /* This format checks out as ok! */
- right_targ = temp;
-
- /* If this is the default target, accept it, even if other
- targets might match. People who want those other targets
- have to set the GNUTARGET variable. */
- if (temp == bfd_default_vector[0])
- goto ok_ret;
-
- if (matching_vector)
- matching_vector[match_count] = temp;
- match_count++;
+ int match_priority = temp->match_priority;
+#if BFD_SUPPORTS_PLUGINS
+ /* If this object can be handled by a plugin, give that the
+ lowest priority; objects both handled by a plugin and
+ with an underlying object format will be claimed
+ separately by the plugin. */
+ if (*target == &plugin_vec)
+ match_priority = (*target)->match_priority;
+#endif
+
+ if (abfd->format != bfd_archive
+ || (bfd_has_map (abfd)
+ && bfd_get_error () != bfd_error_wrong_object_format))
+ {
+ /* If this is the default target, accept it, even if
+ other targets might match. People who want those
+ other targets have to set the GNUTARGET variable. */
+ if (temp == bfd_default_vector[0])
+ goto ok_ret;
+
+ if (matching_vector)
+ matching_vector[match_count] = temp;
+ match_count++;
+
+ if (match_priority < best_match)
+ {
+ best_match = match_priority;
+ best_count = 0;
+ }
+ if (match_priority <= best_match)
+ {
+ /* This format checks out as ok! */
+ right_targ = temp;
+ best_count++;
+ }
+ }
+ else
+ {
+ /* An archive with no armap or objects of the wrong
+ type. We want this target to match if we get no
+ better matches. */
+ if (ar_right_targ != bfd_default_vector[0])
+ ar_right_targ = *target;
+ if (matching_vector)
+ matching_vector[ar_match_index] = *target;
+ ar_match_index++;
+ }
- if (temp->match_priority < best_match)
+ if (preserve_match.marker == NULL)
{
- best_match = temp->match_priority;
- best_count = 0;
+ match_targ = temp;
+ if (!bfd_preserve_save (abfd, &preserve_match))
+ goto err_ret;
}
- best_count++;
- }
- else if (temp
- || (err = bfd_get_error ()) == bfd_error_wrong_object_format
- || err == bfd_error_file_ambiguously_recognized)
- {
- /* An archive with no armap or objects of the wrong type,
- or an ambiguous match. We want this target to match
- if we get no better matches. */
- if (ar_right_targ != bfd_default_vector[0])
- ar_right_targ = *target;
- if (matching_vector)
- matching_vector[ar_match_index] = *target;
- ar_match_index++;
}
- else if (err != bfd_error_wrong_format)
- goto err_ret;
}
if (best_count == 1)
}
}
+ /* We have more than one equally good match. If any of the best
+ matches is a target in config.bfd targ_defvec or targ_selvecs,
+ choose it. */
if (match_count > 1)
{
const bfd_target * const *assoc = bfd_associated_vector;
int i = match_count;
while (--i >= 0)
- if (matching_vector[i] == right_targ)
+ if (matching_vector[i] == right_targ
+ && right_targ->match_priority <= best_match)
break;
if (i >= 0)
}
}
+ /* We still have more than one equally good match, and at least some
+ of the targets support match priority. Choose the first of the
+ best matches. */
+ if (matching_vector && match_count > 1 && best_count != match_count)
+ {
+ int i;
+
+ for (i = 0; i < match_count; i++)
+ {
+ right_targ = matching_vector[i];
+ if (right_targ->match_priority <= best_match)
+ break;
+ }
+ match_count = 1;
+ }
+
+ /* There is way too much undoing of half-known state here. We
+ really shouldn't iterate on live bfd's. Note that saving the
+ whole bfd and restoring it would be even worse; the first thing
+ you notice is that the cached bfd file position gets out of sync. */
+ if (preserve_match.marker != NULL)
+ bfd_preserve_restore (abfd, &preserve_match);
+
if (match_count == 1)
{
abfd->xvec = right_targ;
/* If we come out of the loop knowing that the last target that
matched is the one we want, then ABFD should still be in a usable
- state (except possibly for XVEC). */
+ state (except possibly for XVEC). This is not just an
+ optimisation. In the case of plugins a match against the
+ plugin target can result in the bfd being changed such that
+ it no longer matches the plugin target, nor will it match
+ RIGHT_TARG again. */
if (match_targ != right_targ)
{
+ bfd_reinit (abfd, initial_section_id);
+ bfd_release (abfd, preserve.marker);
if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
goto err_ret;
match_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
+ BFD_ASSERT (match_targ != NULL);
}
ok_ret:
if (matching_vector)
free (matching_vector);
- return TRUE; /* File position has moved, BTW. */
+ if (preserve_match.marker != NULL)
+ bfd_preserve_finish (abfd, &preserve_match);
+ bfd_preserve_finish (abfd, &preserve);
+
+ /* File position has moved, BTW. */
+ return TRUE;
}
if (match_count == 0)
abfd->format = bfd_unknown;
if (matching_vector)
free (matching_vector);
+ if (preserve_match.marker != NULL)
+ bfd_preserve_finish (abfd, &preserve_match);
+ bfd_preserve_restore (abfd, &preserve);
return FALSE;
}
- abfd->xvec = save_targ; /* Restore original target type. */
- abfd->format = bfd_unknown; /* Restore original format. */
+ /* Restore original target type and format. */
+ abfd->xvec = save_targ;
+ abfd->format = bfd_unknown;
bfd_set_error (bfd_error_file_ambiguously_recognized);
if (matching)
*(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;
}