* elfcore.h (elf_core_file_p): Preserve and clear abfd section

information.  Save bfd arch and mach values.  Restore on error.

bfd/ChangeLog

@@ -1,3 +1,8 @@
+2001-11-02  Hans-Peter Nilsson  <hp@axis.com>
+
+	* elfcore.h (elf_core_file_p): Preserve and clear abfd section
+	information.  Save bfd arch and mach values.  Restore on error.
+
 2001-11-02  Alan Modra  <amodra@bigpond.net.au>
 
 	* elf32-hppa.c (hppa_handle_PIC_calls): Rename to mark_PIC_calls.

bfd/elfcore.h

@@ -85,9 +85,18 @@ elf_core_file_p (abfd)
   unsigned int phindex;
   struct elf_backend_data *ebd;
   struct elf_obj_tdata *preserved_tdata = elf_tdata (abfd);
+  struct sec *preserved_sections = abfd->sections;
+  unsigned int preserved_section_count = abfd->section_count;
+  enum bfd_architecture previous_arch = bfd_get_arch (abfd);
+  unsigned long previous_mach = bfd_get_mach (abfd);
   struct elf_obj_tdata *new_tdata = NULL;
   bfd_size_type amt;
 
+  /* Clear section information, since there might be a recognized bfd that
+     we now check if we can replace, and we don't want to append to it.  */
+  abfd->sections = NULL;
+  abfd->section_count = 0;
+
   /* Read in the ELF header in external format.  */
   if (bfd_bread ((PTR) &x_ehdr, (bfd_size_type) sizeof (x_ehdr), abfd)
       != sizeof (x_ehdr))
@@ -234,6 +243,16 @@ elf_core_file_p (abfd)
   return abfd->xvec;
 
 wrong:
+  /* There is way too much undoing of half-known state here.  The caller,
+     bfd_check_format_matches, really shouldn't iterate on live bfd's to
+     check match/no-match like it does.  We have to rely on that a call to
+     bfd_default_set_arch_mach with the previously known mach, undoes what
+     was done by the first bfd_default_set_arch_mach (with mach 0) here.
+     For this to work, only elf-data and the mach may be changed by the
+     target-specific elf_backend_object_p function.  Note that saving the
+     whole bfd here and restoring it would be even worse; the first thing
+     you notice is that the cached bfd file position gets out of sync.  */
+  bfd_default_set_arch_mach (abfd, previous_arch, previous_mach);
   bfd_set_error (bfd_error_wrong_format);
 fail:
   if (i_phdrp != NULL)
@@ -241,5 +260,7 @@ fail:
   if (new_tdata != NULL)
     bfd_release (abfd, new_tdata);
   elf_tdata (abfd) = preserved_tdata;
+  abfd->sections = preserved_sections;
+  abfd->section_count = preserved_section_count;
   return NULL;
 }