[PATCH] PE aouthdr SizeOfHeaders field

[Brian Ford <ford at vss dot fsi dot com>]

While trying to add DWARF2 support to Cygwin/mingw, I came accross the
following buglet:

After compiling and linking a Cygwin app with DWARF2, executing the app
fails with:

-bash: ./app: Permission denied

ls -l app.exe
-rwxr-xr-x    1 ford     None     17876798 Mar 21 17:11 app.exe*

strace ./app.exe
strace.exe: error creating process app.exe, (error 193)

MSDN says error 193 is:
ERROR_BADE_EXE_FORMAT: %1 is not a valid Win32 application

I stumbled on to the fact that objcopy app.exe fixes it.  The file size
grows to:
-rwxr-xr-x    1 ford     None     17898525 Mar 21 17:11 app.exe*

Diffing objdump -x shows (amoung other things):
-SizeOfImage            0194d000
-SizeOfHeaders          00000400
-CheckSum               0111987e
+SizeOfImage            0194c000
+SizeOfHeaders          00000000
+CheckSum               0110d9f8

Hmm..., SizeOfHeaders is output from peXXigen.c
(_bfd_XXi_swap_aouthdr_out).  It is assumed to be the same as the file
offset of the first section (aligned to the section alignment, although,
shouldn't that already be reflected there by definition?).

Anyway, setting a break point there showed the first section to be one I had
accidentally left out of the linker script (.debug_ranges, an orphan) with
a file offset of 0.  Looking at the output of objdump -h shows that alloc
only sections also have a zero file offset.  So,

2004-03-24  Brian Ford  <ford@vss.fsi.com>

	* peXXigen.c (_bfd_XXi_swap_aouthdr_out): Orphan and alloc only
	sections can have a filepos of 0, so use the first non-zero
	filepos for the SizeOfHeaders field.

-- 
Brian Ford
Senior Realtime Software Engineer
VITAL - Visual Simulation Systems
FlightSafety International
Phone: 314-551-8460
Fax:   314-551-8444

Attachment: pe_SizeOfHeaders.patch
Description: Text document