Mail Archives: cygwin-developers/2001/01/26/00:39:56
On Wed, Jan 24, 2001 at 03:33:44PM -0500, DJ Delorie wrote:
>Could people please look at this patch and try it? The original code
>assumed things it shouldn't, and thus you couldn't run, say, objdump
>on MS system DLLs. I like the idea about making bfd dynamic, but I
>refuse to accept patches to this code without a "gut feeling" that it
>will work *and* lots of testing, so the more people test it the
>better.
Shouldn't the PEI*_header stuff come from some w32api file or other?
cgf
>------- Start of forwarded message -------
>Date: Wed, 24 Jan 2001 11:15:05 -0800
>From: "H . J . Lu" <hjl AT valinux DOT com>
>To: DJ Delorie <dj AT redhat DOT com>
>Subject: Re: A PE patch.
>Content-Disposition: inline
>User-Agent: Mutt/1.2.5i
>In-Reply-To: <200101241909 DOT OAA06907 AT greed DOT delorie DOT com>; from dj AT redhat DOT com on Wed, Jan 24, 2001 at 02:09:12PM -0500
>Content-Type: text/plain; charset=us-ascii
>
>Here is the updated version. There is a bug in my old patch.
>
>--
>H.J. Lu (hjl AT valinux DOT com)
>---
>2001-01-23 H.J. Lu <hjl AT gnu DOT org>
>
> * include/coff/pe.h (struct external_PEI_DOS_hdr): New.
> (struct external_PEI_IMAGE_hdr): New.
>
> * bfd/peicode.h (coff_swap_filehdr_in): Remove the e_magic
> checking.
> (pe_bfd_object_p): Rewrite with external_PEI_DOS_hdr and
> external_PEI_IMAGE_hdr.
>
>Index: include/coff/pe.h
>===================================================================
>RCS file: /work/cvs/gnu/binutils/include/coff/pe.h,v
>retrieving revision 1.1.1.7
>diff -u -p -r1.1.1.7 pe.h
>--- include/coff/pe.h 2000/09/05 17:49:11 1.1.1.7
>+++ include/coff/pe.h 2001/01/24 18:46:34
>@@ -125,6 +125,45 @@
> #undef FILNMLEN
> #define FILNMLEN 18 /* # characters in a file name. */
>
>+struct external_PEI_DOS_hdr
>+{
>+ /* DOS header fields - always at offset zero in the EXE file. */
>+ char e_magic[2]; /* Magic number, 0x5a4d. */
>+ char e_cblp[2]; /* Bytes on last page of file, 0x90. */
>+ char e_cp[2]; /* Pages in file, 0x3. */
>+ char e_crlc[2]; /* Relocations, 0x0. */
>+ char e_cparhdr[2]; /* Size of header in paragraphs, 0x4. */
>+ char e_minalloc[2]; /* Minimum extra paragraphs needed, 0x0. */
>+ char e_maxalloc[2]; /* Maximum extra paragraphs needed, 0xFFFF. */
>+ char e_ss[2]; /* Initial (relative) SS value, 0x0. */
>+ char e_sp[2]; /* Initial SP value, 0xb8. */
>+ char e_csum[2]; /* Checksum, 0x0. */
>+ char e_ip[2]; /* Initial IP value, 0x0. */
>+ char e_cs[2]; /* Initial (relative) CS value, 0x0. */
>+ char e_lfarlc[2]; /* File address of relocation table, 0x40. */
>+ char e_ovno[2]; /* Overlay number, 0x0. */
>+ char e_res[4][2]; /* Reserved words, all 0x0. */
>+ char e_oemid[2]; /* OEM identifier (for e_oeminfo), 0x0. */
>+ char e_oeminfo[2]; /* OEM information; e_oemid specific, 0x0. */
>+ char e_res2[10][2]; /* Reserved words, all 0x0. */
>+ char e_lfanew[4]; /* File address of new exe header, usually 0x80. */
>+ char dos_message[16][4]; /* Other stuff, always follow DOS header. */
>+};
>+
>+struct external_PEI_IMAGE_hdr
>+{
>+ char nt_signature[4]; /* required NT signature, 0x4550. */
>+
>+ /* From standard header. */
>+ char f_magic[2]; /* Magic number. */
>+ char f_nscns[2]; /* Number of sections. */
>+ char f_timdat[4]; /* Time & date stamp. */
>+ char f_symptr[4]; /* File pointer to symtab. */
>+ char f_nsyms[4]; /* Number of symtab entries. */
>+ char f_opthdr[2]; /* Sizeof(optional hdr). */
>+ char f_flags[2]; /* Flags. */
>+};
>+
> struct external_PEI_filehdr
> {
> /* DOS header fields - always at offset zero in the EXE file. */
>Index: bfd/peicode.h
>===================================================================
>RCS file: /work/cvs/gnu/binutils/bfd/peicode.h,v
>retrieving revision 1.9
>diff -u -p -r1.9 peicode.h
>--- bfd/peicode.h 2001/01/23 20:11:14 1.9
>+++ bfd/peicode.h 2001/01/24 18:36:09
>@@ -208,26 +208,6 @@ coff_swap_filehdr_in (abfd, src, dst)
> filehdr_dst->f_flags = bfd_h_get_16(abfd, (bfd_byte *)filehdr_src-> f_flags);
> filehdr_dst->f_symptr = bfd_h_get_32 (abfd, (bfd_byte *) filehdr_src->f_symptr);
>
>-#ifdef COFF_IMAGE_WITH_PE
>- /* 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 0
>- /* We can't assume that the PE header is at offset 0x80. When it
>- isn't, the DOS header isn't read correctly, so we can't assume
>- e_magic is set even for valid PE files. */
>- if (bfd_h_get_16 (abfd, (bfd_byte *) filehdr_src->e_magic) != DOSMAGIC)
>- filehdr_dst->f_magic = -1;
>-#endif
>-#endif
>-
> /* Other people's tools sometimes generate headers with an nsyms but
> a zero symptr. */
> if (filehdr_dst->f_nsyms != 0 && filehdr_dst->f_symptr == 0)
>@@ -1255,16 +1235,10 @@ _("%s: Recognised but unhandled machine
> static const bfd_target *
> pe_bfd_object_p (bfd * abfd)
> {
>- /* We need 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 buffer[4];
>+ struct external_PEI_DOS_hdr dos_hdr;
>+ struct external_PEI_IMAGE_hdr image_hdr;
> file_ptr offset;
>- unsigned long signature;
>
> /* Detect if this a Microsoft Import Library Format element. */
> if (bfd_seek (abfd, 0x00, SEEK_SET) != 0
>@@ -1275,44 +1249,56 @@ pe_bfd_object_p (bfd * abfd)
> return NULL;
> }
>
>- signature = bfd_h_get_32 (abfd, buffer);
>-
>- if (signature == 0xffff0000)
>+ if (bfd_h_get_32 (abfd, buffer) == 0xffff0000)
> return pe_ILF_object_p (abfd);
>
>- if (bfd_seek (abfd, 0x3c, SEEK_SET) != 0
>- || bfd_read (buffer, 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, buffer);
>+ /* 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;
>+ }
>
>- if (bfd_seek (abfd, offset, SEEK_SET) != 0
>- || bfd_read (buffer, 1, 4, abfd) != 4)
>+ 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, buffer);
>
>- 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 i386 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)
> {
>------- End of forwarded message -------
--
cgf AT cygnus DOT com Red Hat, Inc.
http://sources.redhat.com/ http://www.redhat.com/
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