2001-06-02 H.J. Lu <hjl@gnu.org>

	* coff-ia64.c (ia64coff_object_p): Rewrite with
	external_PEI_DOS_hdr and external_PEI_IMAGE_hdr.

1 files changed, 31 insertions, 24 deletions

diff --git a/bfd/coff-ia64.c b/bfd/coff-ia64.c
index 5b10e3b88df..776d3fac596 100644
--- a/bfd/coff-ia64.c
+++ b/bfd/coff-ia64.c
@@ -68,51 +68,58 @@ ia64coff_object_p (abfd)
      bfd *abfd;
 {
 #ifdef COFF_IMAGE_WITH_PE
-  /* We need to hack badly to handle a PE image correctly.  In PE
-     images created by the GNU linker, the offset to the COFF header
-     is always the size.  However, this is not the case in images
-     generated by other PE linkers.  The PE format stores a four byte
-     offset to the PE signature just before the COFF header at
-     location 0x3c of the file.  We pick up that offset, verify that
-     the PE signature is there, and then set ourselves up to read in
-     the COFF header.  */
   {
-    bfd_byte ext_offset[4];
+    struct external_PEI_DOS_hdr dos_hdr;
+    struct external_PEI_IMAGE_hdr image_hdr;
     file_ptr offset;
-    bfd_byte ext_signature[4];
-    unsigned long signature;
 
-    if (bfd_seek (abfd, 0x3c, SEEK_SET) != 0
-	|| bfd_read (ext_offset, 1, 4, abfd) != 4)
+    if (bfd_seek (abfd, 0x00, SEEK_SET) != 0
+	|| bfd_read (&dos_hdr, 1, sizeof (dos_hdr), abfd)
+	   != sizeof (dos_hdr))
       {
 	if (bfd_get_error () != bfd_error_system_call)
 	  bfd_set_error (bfd_error_wrong_format);
 	return NULL;
       }
-    offset = bfd_h_get_32 (abfd, ext_offset);
-    if (bfd_seek (abfd, offset, SEEK_SET) != 0
-	|| bfd_read (ext_signature, 1, 4, abfd) != 4)
+
+    /* There are really two magic numbers involved; the magic number
+       that says this is a NT executable (PEI) and the magic number
+       that determines the architecture.  The former is DOSMAGIC,
+       stored in the e_magic field.  The latter is stored in the
+       f_magic field.  If the NT magic number isn't valid, the
+       architecture magic number could be mimicked by some other
+       field (specifically, the number of relocs in section 3).  Since
+       this routine can only be called correctly for a PEI file, check
+       the e_magic number here, and, if it doesn't match, clobber the
+       f_magic number so that we don't get a false match.  */
+    if (bfd_h_get_16 (abfd, (bfd_byte *) dos_hdr.e_magic) != DOSMAGIC)
+      {
+	bfd_set_error (bfd_error_wrong_format);
+	return NULL;
+      }
+
+    offset = bfd_h_get_32 (abfd, (bfd_byte *) dos_hdr.e_lfanew);
+    if (bfd_seek (abfd, (file_ptr) offset, SEEK_SET) != 0
+	|| bfd_read (&image_hdr, 1, sizeof (image_hdr), abfd)
+	   != sizeof (image_hdr))
       {
 	if (bfd_get_error () != bfd_error_system_call)
 	  bfd_set_error (bfd_error_wrong_format);
 	return NULL;
       }
-    signature = bfd_h_get_32 (abfd, ext_signature);
 
-    if (signature != 0x4550)
+    if (bfd_h_get_32 (abfd, (bfd_byte *) image_hdr.nt_signature)
+	!= 0x4550)
       {
 	bfd_set_error (bfd_error_wrong_format);
 	return NULL;
       }
 
     /* Here is the hack.  coff_object_p wants to read filhsz bytes to
-       pick up the COFF header.  We adjust so that that will work.  20
-       is the size of the COFF filehdr.  */
-
+       pick up the COFF header for PE, see "struct external_PEI_filehdr"
+       in include/coff/pe.h.  We adjust so that that will work. */
     if (bfd_seek (abfd,
-		  (bfd_tell (abfd)
-		   - bfd_coff_filhsz (abfd)
-		   + 20),
+		  (file_ptr) (offset - sizeof (dos_hdr)),
 		  SEEK_SET)
 	!= 0)
       {