A patch for bfd/format.c

["H . J . Lu" <hjl at valinux dot com>]

I have binutils configured as

# .../configure --enable-targets=all --enable-64-bit-bfd

For the file, foo.o, in a.out enclosed here, I got

# .../objdump -dw foo.o
lt-objdump: foo.o: Success

The problem is bfd_check_format_matches will call each target
to check if it matches with the .o file. pe_bfd_object_p in
bfd/peicode.h has


   1293   offset = bfd_h_get_32 (abfd, buffer);
   1294 
   1295   if (bfd_seek (abfd, offset, SEEK_SET) != 0
   1296       || bfd_read (buffer, 1, 4, abfd) != 4)
   1297     {
   1298       if (bfd_get_error () != bfd_error_system_call)
   1299         bfd_set_error (bfd_error_wrong_format);
   1300       return NULL;
   1301     }

The problem was it got a wild offset and bfd set error to
bfd_error_system_call. I don't know for sure when
bfd_check_format_matches () should stop checking the next target.
But bfd_error_system_call shouldn't stop it. With my patch, I got

# .../objdump -dw foo.o
lt-objdump: foo.o: File format is ambiguous
lt-objdump: Matching formats: a.out-cris a.out-i386 a.out-i386-bsd a.out-i386-lynx a.out-m88k-mach3 a.out-pc532-mach


-- 
H.J. Lu (hjl@valinux.com)
---
2000-11-17  H.J. Lu  <hjl@gnu.org>

	* format.c (bfd_check_format_matches): Don't return if get
	bfd_error_system_call.

Index: format.c
===================================================================
RCS file: /work/cvs/gnu/binutils/bfd/format.c,v
retrieving revision 1.1.1.2
diff -u -p -r1.1.1.2 format.c
--- format.c	2000/07/20 03:27:55	1.1.1.2
+++ format.c	2000/11/17 22:08:00
@@ -254,13 +254,14 @@ bfd_check_format_matches (abfd, format, 
 	  break;
 #endif
 	}
-      else if (bfd_get_error () != bfd_error_wrong_format)
+      else if (bfd_get_error () != bfd_error_wrong_format
+	       && bfd_get_error () != bfd_error_system_call)
 	{
 	  abfd->xvec = save_targ;
 	  abfd->format = bfd_unknown;
 	  
 	  if (matching && bfd_get_error ()
-	      != bfd_error_file_ambiguously_recognized)
+			  != bfd_error_file_ambiguously_recognized)
 	    free (matching_vector);
 	  
 	  return false;

foo.o