* RFA: Fix both_direction
@ 2005-05-11 18:05 Daniel Jacobowitz
2005-05-16 16:21 ` Daniel Jacobowitz
0 siblings, 1 reply; 3+ messages in thread
From: Daniel Jacobowitz @ 2005-05-11 18:05 UTC (permalink / raw)
To: binutils
This patch fixes "gdb -write" support for ELF files. There are two
problems:
We try to write out the string table even if we didn't create one. If we've
bypassed the normal output routines, we never initialize elf_shstrtab, which
is otherwise OK. If it's not set, there's nothing we need to do (except not
crash).
With that fixed, gdb -write works - as long as you change something, thereby
encountering the "output_has_begun = TRUE" in bfd_set_section_contents. If
you don't, then the linker's output routines are called. This causes
sections to get rearranged, destroys special program headers (like
PT_GNU_STACK), and loses the static symbol table. I believe that the
check_format hook is a better place to handle this.
OK? Tested on i686-linux, using the binutils testsuite, the gdb testsuite,
and manual testing of gdb -write (which needs some testsuite coverage of its
own).
--
Daniel Jacobowitz
CodeSourcery, LLC
2005-05-11 Daniel Jacobowitz <dan@codesourcery.com>
* elf.c (_bfd_elf_write_object_contents): Check for non-NULL
elf_shstrtab.
* format.c (bfd_check_format_matches): Set output_has_begun
for both_direction.
* section.c (bfd_set_section_contents): Use bfd_write_p. Remove
special case for both_direction.
Index: bfd/elf.c
===================================================================
RCS file: /cvs/src/src/bfd/elf.c,v
retrieving revision 1.291
diff -u -p -r1.291 elf.c
--- bfd/elf.c 7 May 2005 13:22:45 -0000 1.291
+++ bfd/elf.c 11 May 2005 15:55:51 -0000
@@ -4912,8 +4912,9 @@ _bfd_elf_write_object_contents (bfd *abf
}
/* Write out the section header names. */
- if (bfd_seek (abfd, elf_tdata (abfd)->shstrtab_hdr.sh_offset, SEEK_SET) != 0
- || ! _bfd_elf_strtab_emit (abfd, elf_shstrtab (abfd)))
+ if (elf_shstrtab (abfd) != NULL
+ && (bfd_seek (abfd, elf_tdata (abfd)->shstrtab_hdr.sh_offset, SEEK_SET) != 0
+ || ! _bfd_elf_strtab_emit (abfd, elf_shstrtab (abfd))))
return FALSE;
if (bed->elf_backend_final_write_processing)
Index: bfd/format.c
===================================================================
RCS file: /cvs/src/src/bfd/format.c,v
retrieving revision 1.20
diff -u -p -r1.20 format.c
--- bfd/format.c 4 May 2005 15:53:31 -0000 1.20
+++ bfd/format.c 11 May 2005 15:55:51 -0000
@@ -173,6 +173,14 @@ bfd_check_format_matches (bfd *abfd, bfd
if (matching)
free (matching_vector);
+ /* If the file was opened for update, then `output_has_begun'
+ some time ago when the file was created. Do not recompute
+ sections sizes or alignments in _bfd_set_section_contents.
+ We can not set this flag until after checking the format,
+ because it will interfere with creation of BFD sections. */
+ if (abfd->direction == both_direction)
+ abfd->output_has_begun = TRUE;
+
return TRUE; /* File position has moved, BTW. */
}
@@ -319,6 +327,14 @@ bfd_check_format_matches (bfd *abfd, bfd
if (matching)
free (matching_vector);
+ /* If the file was opened for update, then `output_has_begun'
+ some time ago when the file was created. Do not recompute
+ sections sizes or alignments in _bfd_set_section_contents.
+ We can not set this flag until after checking the format,
+ because it will interfere with creation of BFD sections. */
+ if (abfd->direction == both_direction)
+ abfd->output_has_begun = TRUE;
+
return TRUE; /* File position has moved, BTW. */
}
Index: bfd/section.c
===================================================================
RCS file: /cvs/src/src/bfd/section.c,v
retrieving revision 1.87
diff -u -p -r1.87 section.c
--- bfd/section.c 5 May 2005 14:34:04 -0000 1.87
+++ bfd/section.c 11 May 2005 15:55:52 -0000
@@ -1346,22 +1346,10 @@ bfd_set_section_contents (bfd *abfd,
return FALSE;
}
- switch (abfd->direction)
+ if (!bfd_write_p (abfd))
{
- case read_direction:
- case no_direction:
bfd_set_error (bfd_error_invalid_operation);
return FALSE;
-
- case write_direction:
- break;
-
- case both_direction:
- /* File is opened for update. `output_has_begun' some time ago when
- the file was created. Do not recompute sections sizes or alignments
- in _bfd_set_section_content. */
- abfd->output_has_begun = TRUE;
- break;
}
/* Record a copy of the data in memory if desired. */
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: RFA: Fix both_direction
2005-05-11 18:05 RFA: Fix both_direction Daniel Jacobowitz
@ 2005-05-16 16:21 ` Daniel Jacobowitz
2005-05-17 7:39 ` Alan Modra
0 siblings, 1 reply; 3+ messages in thread
From: Daniel Jacobowitz @ 2005-05-16 16:21 UTC (permalink / raw)
To: binutils
On Wed, May 11, 2005 at 01:31:53PM -0400, Daniel Jacobowitz wrote:
> This patch fixes "gdb -write" support for ELF files. There are two
> problems:
>
> We try to write out the string table even if we didn't create one. If we've
> bypassed the normal output routines, we never initialize elf_shstrtab, which
> is otherwise OK. If it's not set, there's nothing we need to do (except not
> crash).
>
> With that fixed, gdb -write works - as long as you change something, thereby
> encountering the "output_has_begun = TRUE" in bfd_set_section_contents. If
> you don't, then the linker's output routines are called. This causes
> sections to get rearranged, destroys special program headers (like
> PT_GNU_STACK), and loses the static symbol table. I believe that the
> check_format hook is a better place to handle this.
>
> OK? Tested on i686-linux, using the binutils testsuite, the gdb testsuite,
> and manual testing of gdb -write (which needs some testsuite coverage of its
> own).
> 2005-05-11 Daniel Jacobowitz <dan@codesourcery.com>
>
> * elf.c (_bfd_elf_write_object_contents): Check for non-NULL
> elf_shstrtab.
> * format.c (bfd_check_format_matches): Set output_has_begun
> for both_direction.
> * section.c (bfd_set_section_contents): Use bfd_write_p. Remove
> special case for both_direction.
Ping?
--
Daniel Jacobowitz
CodeSourcery, LLC
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: RFA: Fix both_direction
2005-05-16 16:21 ` Daniel Jacobowitz
@ 2005-05-17 7:39 ` Alan Modra
0 siblings, 0 replies; 3+ messages in thread
From: Alan Modra @ 2005-05-17 7:39 UTC (permalink / raw)
To: binutils
On Mon, May 16, 2005 at 10:28:28AM -0400, Daniel Jacobowitz wrote:
> On Wed, May 11, 2005 at 01:31:53PM -0400, Daniel Jacobowitz wrote:
> > This patch fixes "gdb -write" support for ELF files. There are two
> > problems:
> >
> > We try to write out the string table even if we didn't create one. If we've
> > bypassed the normal output routines, we never initialize elf_shstrtab, which
> > is otherwise OK. If it's not set, there's nothing we need to do (except not
> > crash).
> >
> > With that fixed, gdb -write works - as long as you change something, thereby
> > encountering the "output_has_begun = TRUE" in bfd_set_section_contents. If
> > you don't, then the linker's output routines are called. This causes
> > sections to get rearranged, destroys special program headers (like
> > PT_GNU_STACK), and loses the static symbol table. I believe that the
> > check_format hook is a better place to handle this.
> >
> > OK? Tested on i686-linux, using the binutils testsuite, the gdb testsuite,
> > and manual testing of gdb -write (which needs some testsuite coverage of its
> > own).
>
> > 2005-05-11 Daniel Jacobowitz <dan@codesourcery.com>
> >
> > * elf.c (_bfd_elf_write_object_contents): Check for non-NULL
> > elf_shstrtab.
> > * format.c (bfd_check_format_matches): Set output_has_begun
> > for both_direction.
> > * section.c (bfd_set_section_contents): Use bfd_write_p. Remove
> > special case for both_direction.
>
> Ping?
The idea looks OK to me.
--
Alan Modra
IBM OzLabs - Linux Technology Centre
^ permalink raw reply [flat|nested] 3+ messages in thread
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2005-05-11 18:05 RFA: Fix both_direction Daniel Jacobowitz
2005-05-16 16:21 ` Daniel Jacobowitz
2005-05-17 7:39 ` Alan Modra
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