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Andrew Burgess ace667e59a ld: Restore file offset after a plugin fails to claim a file
When using the plugin interface to claim an input file the claim method
from (possible) many plugins can be called on an input file.  If these
claim methods read content from the input file then the file offset
stored in the underlying file descriptor will change.

As we share a file descriptor between the plugin interface (created with
dup in ld/plugin.c:plugin_object_p) and the input bfd object, then any
changes to the file offset in the file descriptor will effect the bfd
object.  Also, as the changes to the file offset did not originate from
calls through the bfd interface, but instead came from the plugin
directly, then the bfd will not be aware that the file offset has
changed.  This is a problem as the bfd library caches the file offset.
If the plugin decides not to claim an input file then, currently, we
leave the bfd in a state where the actual file offset is out of sync
with the cached file offset.

This problem came to light after a recent commit
7d0b9ebc1e (Don't include libbfd.h outside
of bfd, part 6) however, I don't believe that commit actual introduces
the bug, it just exposed the existing issue.

This commit solves the problem by backing up and restoring the file
offset for the file descriptor of the input file.  The restore is only
done if the plugin does not claim the input file, as it is in this case
that the bfd library might be used again to try and identify the
unclaimed file.

ld/ChangeLog:

	* plugin.c (plugin_call_claim_file): Restore the file offset after
	an unsuccessful attempt to claim a file.
	* testplug.c (bytes_to_read_before_claim): New global.
	(record_read_length): New function, sets new global
	bytes_to_read_before_claim.
	(parse_option): Handle 'read:<NUMBER>' option.
	(onclaim_file): Read file content before checking for claim.
	* testsuite/ld-plugin/plugin-30.d: New file.
	* testsuite/ld-plugin/plugin.exp: Add new test.
2016-07-19 09:58:01 +01:00
bfd Automatic date update in version.in 2016-07-19 00:00:21 +00:00
binutils Don't include libbfd.h outside of bfd, part 6 2016-07-16 19:09:00 +09:30
config
cpu
elfcpp Add support for MIPS .rld_map section. 2016-06-20 12:16:26 -07:00
etc Fix compile time warning messages building with gcc v6.1.1 2016-06-13 10:49:26 +01:00
gas Don't include libbfd.h outside of bfd, part 2 2016-07-16 13:27:30 +09:30
gdb GDB testsuite: Escape paths used in regular expressions 2016-07-15 11:19:19 -07:00
gold Fix gold testsuite failure with GCC 6. 2016-06-29 23:24:35 -07:00
gprof
include Add support for creating ELF import libraries 2016-07-15 17:50:48 +01:00
intl
ld ld: Restore file offset after a plugin fails to claim a file 2016-07-19 09:58:01 +01:00
libdecnumber
libiberty Don't needlessly clear xmemdup allocated memory. 2016-05-31 20:34:47 +09:30
opcodes MIPS/opcodes: Address issues with NAL disassembly 2016-07-13 17:42:43 +01:00
readline
sim Update PC when simulate break instruction. 2016-07-19 09:47:23 +03:00
texinfo
zlib
.cvsignore
.gitattributes
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ChangeLog [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
compile
config-ml.in
config.guess Fix typo introduced during the most recent synchronization update. 2016-05-27 14:34:06 +01:00
config.rpath
config.sub Sync config.guess and config.sub with FSF GCC mainline versions 2016-05-23 11:42:17 +01:00
configure [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
configure.ac [TILEPro] Don't build gdb 2016-06-28 14:16:15 -04:00
COPYING
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
COPYING3
COPYING3.LIB
depcomp
djunpack.bat
install-sh
libtool.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
lt~obsolete.m4
MAINTAINERS
Makefile.def
Makefile.in Add dependencies to configure rule 2016-05-28 22:36:04 +09:30
Makefile.tpl Add dependencies to configure rule 2016-05-28 22:36:04 +09:30
makefile.vms
missing
mkdep
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
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REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.