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RFA: Fix both_direction
- From: Daniel Jacobowitz <drow at false dot org>
- To: binutils at sources dot redhat dot com
- Date: Wed, 11 May 2005 13:31:53 -0400
- Subject: RFA: Fix both_direction
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. */