objcopy: Add --update-section option.

New option for objcopy --update-section allows the contents of a section
to be updated while maintaining the section flags, and, for ELF files,
the section to segment mapping.

New test uses --dump-section and --update-section to check that a
section can be made larger and smaller with an update.

binutils/ChangeLog:

	* objcopy.c (update_sections): New list.
	(command_line_switch): Add OPTION_UPDATE_SECTION.
	(copy_options): Add update-section.
	(copy_usage): Document new option.
	(is_update_section): New function.
	(is_strip_section_1): Add check for attempt to update and remove
	the same section.
	(copy_object): Update size and content of requested sections.
	(skip_section): Don't copy for updated sections.
	(copy_main): Handle --update-section.
	* doc/binutils.texi (objcopy): Add description of --update-section
	option.
	* NEWS: Mention --update-section option.

binutils/testsuite/ChangeLog:

	* binutils-all/update-1.s: New file.
	* binutils-all/update-2.s: New file.
	* binutils-all/update-3.s: New file.
	* binutils-all/update-4.s: New file.
	* binutils-all/update-section.exp: New file.

1 files changed, 16 insertions, 0 deletions

diff --git a/binutils/doc/binutils.texi b/binutils/doc/binutils.texi
index a5bfd4c..d63c04c 100644
--- a/binutils/doc/binutils.texi
+++ b/binutils/doc/binutils.texi
@@ -1091,6 +1091,7 @@ objcopy [@option{-F} @var{bfdname}|@option{--target=}@var{bfdname}]
         [@option{--set-section-flags} @var{sectionpattern}=@var{flags}]
         [@option{--add-section} @var{sectionname}=@var{filename}]
         [@option{--dump-section} @var{sectionname}=@var{filename}]
+        [@option{--update-section} @var{sectionname}=@var{filename}]
         [@option{--rename-section} @var{oldname}=@var{newname}[,@var{flags}]]
         [@option{--long-section-names} @{enable,disable,keep@}]
         [@option{--change-leading-char}] [@option{--remove-leading-char}]
@@ -1489,6 +1490,21 @@ that it does not create a formatted file, it just dumps the contents
 as raw binary data, without applying any relocations.  The option can
 be specified more than once.
 
+@item --update-section @var{sectionname}=@var{filename}
+Replace the existing contents of a section named @var{sectionname}
+with the contents of file @var{filename}.  The size of the section
+will be adjusted to the size of the file.  The section flags for
+@var{sectionname} will be unchanged.  For ELF format files the section
+to segment mapping will also remain unchanged, something which is not
+possible using @option{--remove-section} followed by
+@option{--add-section}.  The option can be specified more than once.
+
+Note - it is possible to use @option{--rename-section} and
+@option{--update-section} to both update and rename a section from one
+command line.  In this case, pass the original section name to
+@option{--update-section}, and the original and new section names to
+@option{--rename-section}.
+
 @item --rename-section @var{oldname}=@var{newname}[,@var{flags}]
 Rename a section from @var{oldname} to @var{newname}, optionally
 changing the section's flags to @var{flags} in the process.  This has