Another BFD corefile issue

["Michael Snyder" <msnyder@cygnus.com>]

Also in elfcore.h, elf64_core_file_p may be called more than once from
bfd_check_format_matches.  If an earlier call matches, and a later call
ALMOST matches, it may clobber the earlier allocated pointer for
elf_obj_data.  I believe that the elf_zalloc call for elf_obj_data is done
too early, and I would like to move it down to just before it is actually
needed -- thus reducing the chance of it being called on a near-match.

The circumstance where this bites us is when elf64-sparc target comes
before elf64-big.

2000-04-06  Michael Snyder  <msnyder@seadog.cygnus.com>

        * elfcore.h (elf_core_file_p): delay allocating elf_obj_data
        until it is needed, reducing the chances of memory leaks or
        good data being clobbered unnecessarily.

Index: elfcore.h
===================================================================
RCS file: /cvs/src/src/bfd/elfcore.h,v
retrieving revision 1.1.1.1
diff -c -r1.1.1.1 elfcore.h
*** elfcore.h   1999/05/03 07:28:57     1.1.1.1
--- elfcore.h   2000/04/07 03:04:12
***************
*** 124,137 ****
        goto wrong;
      }

-   /* Give abfd an elf_obj_tdata. */
-   elf_tdata (abfd) =
-     (struct elf_obj_tdata *) bfd_zalloc (abfd, sizeof (struct
elf_obj_tdata));
-   if (elf_tdata (abfd) == NULL)
-     return NULL;
-
-   /* FIXME: from here on down, "goto wrong" will leak memory.  */
-
    /* Swap in the rest of the header, now that we have the byte order. */
    i_ehdrp = elf_elfheader (abfd);
    elf_swap_ehdr_in (abfd, &x_ehdr, i_ehdrp);
--- 124,129 ----
***************
*** 191,196 ****
--- 183,197 ----
    if (!i_phdrp)
      return NULL;

+   /* Give abfd an elf_obj_tdata. */
+   elf_tdata (abfd) =
+     (struct elf_obj_tdata *) bfd_zalloc (abfd, sizeof (struct
elf_obj_tdata));
+   if (elf_tdata (abfd) == NULL)
+     return NULL;
+
+   /* FIXME: from here on down, "goto wrong" will leak memory.
+      As will "return NULL".  */
+
    elf_tdata (abfd)->phdr = i_phdrp;

    /* Read and convert to internal form. */