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.
[PATCH] Add infrastructure for plugin API; functionality to follow.
include/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 1/6).
* plugin-api.h (LDPT_GNU_LD_VERSION): New ld_plugin_tag enum member.
ld/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 1/6).
* configure.in: Add AC_CHECKs for file io and dlfcn headers and
functions and AC_SEARCH for -ldl.
(enable_plugins): New shell variable set if above tests find dlopen
functionality.
(ENABLE_PLUGINS): Add related automake conditional.
* configure: Regenerate.
* config.in: Likewise.
* Makefile.am (PLUGIN_C): Declare plugin C source file, conditional
on ENABLE_PLUGINS being defined.
(PLUGIN_H): Likewise for header file.
(PLUGIN_OBJECT): Likewise for object file.
(PLUGIN_CFLAGS): Likewise -D flag required to compile plugin support.
(AM_CPPFLAGS): Use PLUGIN_CFLAGS.
(CFILES): Use PLUGIN_C.
(HFILES): Use PLUGIN_H.
(OFILES): Use PLUGIN_OBJECT.
(ld_new_SOURCES): Use PLUGIN_C.
(noinst_LTLIBRARIES)[ENABLE_PLUGINS]: Declare test plugin.
(libldtestplug_la_SOURCES)[ENABLE_PLUGINS]: Add automake definition
for test plugin.
(libldtestplug_la_CFLAGS)[ENABLE_PLUGINS]: Likewise.
(libldtestplug_la_LDFLAGS)[ENABLE_PLUGINS]: Likewise.
* Makefile.in: Regenerate.
* sysdep.h: Include stdarg.h, unistd.h and one of fcntl.h or
sys/file.h where available. Include dlfcn.h when ENABLE_PLUGINS.
(O_RDONLY): Supply default definition likewise to bfd's sysdep.h
(O_WRONLY): Likewise.
(O_RDWR): Likewise.
(O_ACCMODE): Likewise.
(O_BINARY): Likewise.
(SEEK_SET): Likewise.
(SEEK_CUR): Likewise.
(SEEK_END): Likewise.
* ldmisc.c (vfinfo): Make non-static. Add %p format char.
* ldmisc.h (vfinfo): Declare extern prototype.
* lexsup.c (enum option_values)[ENABLE_PLUGINS]: Add new entries for
OPTION_PLUGIN and OPTION_PLUGIN_OPT.
(ld_options[])[ENABLE_PLUGINS]: Add option data for the above two.
(parse_args)[ENABLE_PLUGINS]: Handle them, and load all plugins once
option parsing is complete.
* ldmain.c (main)[ENABLE_PLUGINS]: Call plugin cleanup hooks just
after lang_finish.
* plugin.c: New source file.
* plugin.h: Likewise new header.
* testplug.c: New source file.
ld/testsuite/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 1/6).
* ld-bootstrap/bootstrap.exp: Skip static tests also if LD plugins
are enabled.
* lib/ld-lib.exp (proc regexp_diff): Extend verbose debug output.
(proc set_file_contents): Write a file with the supplied content.
(run_ld_link_tests): Add new 'ld' action to test linker output.
(proc check_plugin_api_available): Return true if linker under test
supports the plugin API.
* ld-plugin/func.c: New test source file.
* ld-plugin/main.c: Likewise.
* ld-plugin/text.c: Likewise.
* ld-plugin/plugin-1.d: New dump test output pattern script.
* ld-plugin/plugin-2.d: Likewise.
* ld-plugin/plugin-3.d: Likewise.
* ld-plugin/plugin-4.d: Likewise.
* ld-plugin/plugin-5.d: Likewise.
* ld-plugin/plugin.exp: New test control script.
---
[PATCH] Implement claim file and all symbols read hooks and add symbols callback.
ld/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 2/6).
* ldfile.c (ldfile_try_open_bfd)[ENABLE_PLUGINS]: Don't return early
during compat checks if they pass, instead offer any successfully
opened and accepted file to the plugin claim file hooks chain. Create
a dummy bfd to accept symbols added by the plugin, if the plugin
claims the file.
* ldlang.c (lang_process)[ENABLE_PLUGINS]: Call plugin all symbols
read hook chain before ldemul_after_open.
* ldlang.h (struct lang_input_statement_struct): Add new single-bit
'claimed' flag.
* plugin.c (IRONLY_SUFFIX): New macro for dummy bfd file suffix.
(IRONLY_SUFFIX_LEN): Length of the above string.
(plugin_get_ir_dummy_bfd): New function to create the dummy bfd used
to store symbols for ir-only files.
(is_ir_dummy_bfd): New function to check if a bfd is ir-only.
(asymbol_from_plugin_symbol): New function converts symbol formats.
(add_symbols): Call it to convert plugin syms to bfd syms and add
them to the dummy bfd.
* plugin.h: Add missing include guards.
(plugin_get_ir_dummy_bfd): Add prototype.
(is_ir_dummy_bfd): Likewise.
* testplug.c (TV_MESSAGE): New helper macro.
(struct claim_file): New struct.
(claim_file_t): New typedef.
(tag_names[]): Make static and const.
(claimfiles_list): New variable.
(claimfiles_tail_chain_ptr): Likewise.
(last_claimfile): Likewise.
(record_claim_file): Record a file to claim on a singly-linked list.
(parse_symdefstr): Parse an ASCII representation of a symbol from a
plugin option into the fields of a struct ld_plugin_symbol.
(record_claimed_file_symbol): Use it to parse plugin option for
adding a symbol.
(parse_option): Parse claim file and add symbol options.
(dump_tv_tag): Use TV_MESSAGE.
(onload): Likewise.
(onclaim_file): Make static. Use TV_MESSAGE. Scan list of files to
claim and claim this file if required, adding any symbols specified.
(onall_symbols_read): Make static and use TV_MESSAGE.
(oncleanup): Likewise.
ld/testsuite/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 2/6).
* ld-plugin/plugin-3.d: Enable regexes for new functionality.
* ld-plugin/plugin-5.d: Likewise.
* ld-plugin/plugin-6.d: New testcase.
* ld-plugin/plugin-7.d: Likewise.
* ld-plugin/plugin.exp: Use 'nm' on compiled test objects to determine
whether symbols in plugin arguments need an underscore prefix. Add
new plugin-6.d and plugin-7.d testcases.
---
[PATCH] Implement get symbols callback.
ld/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 3/6).
* ldmain.c (notice)[ENABLE_PLUGINS]: Call plugin_notice.
* plugin.c (non_ironly_hash): Add new bfd hash table.
(plugin_load_plugins): Exit early if no plugins to load. If plugins
do load successfully, set notice_all flag in link info.
(get_symbols): Implement.
(plugin_load_plugins): Exit early if no plugins to load, else after
loading plugins successfully enable notice_all mode.
(init_non_ironly_hash): Lazily init non_ironly_hash table.
(plugin_notice): Record symbols referenced from non-IR files in the
non_ironly_hash. Suppress tracing, cref generation and nocrossrefs
tracking for symbols from dummy IR bfds.
* plugin.h: Fix formatting.
(plugin_notice): Add prototype.
* testplug.c (dumpresolutions): New global var.
(parse_options): Accept "dumpresolutions".
(onall_symbols_read): Get syms and dump resolutions if it was given.
ld/testsuite/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 3/6).
* ld-plugin/plugin-8.d: New testcase.
* ld-plugin/plugin.exp: Invoke it.
---
[PATCH] Implement add input file, add input lib and set extra lib path callbacks.
ld/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 4/6).
* ldlang.c (lang_process)[ENABLE_PLUGINS]: Move invocation of
plugin_call_all_symbols_read to before setting of gc_sym_list, and
open any new input files that may have been added during it.
* ldmain.c (multiple_definition)[ENABLE_PLUGINS]: Call out to
plugin_multiple_definition and let it have first say over what to do
with the clashing definitions.
* plugin.c (no_more_claiming): New boolean variable.
(plugin_cached_allow_multiple_defs): Likewise.
(add_input_file): Implement.
(add_input_library): Likewise.
(set_extra_library_path): Likewise.
(plugin_call_claim_file): Don't do anything when no_more_claiming set.
(plugin_call_all_symbols_read): Set it. Disable link info
"allow_multiple_definition" flag, but cache its value.
(plugin_multiple_definition): New function.
* plugin.h (plugin_multiple_definition): Add prototype.
* testplug.c (addfile_enum_t): New enumerated typedef.
(add_file_t): New struct typedef.
(addfiles_list): New variable.
(addfiles_tail_chain_ptr): Likewise.
(record_add_file): New function.
(parse_option): Parse "add:", "lib:" and "dir:" options and call it.
(onall_symbols_read): Iterate the list of new files, libs and dirs,
adding them.
ld/testsuite/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 4/6).
* ld-plugin/plugin-9.d: New testcase.
* ld-plugin/plugin.exp: Invoke it.
---
[PATCH] Add ELF symbol visibility support to plugin interface.
ld/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 5/6).
* plugin.c (asymbol_from_plugin_symbol): If the bfd is an ELF bfd,
find the elf symbol data and set the visibility in the st_other field.
ld/testsuite/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 5/6).
* ld-plugin/plugin-ignore.d: New dump test control script.
* ld-plugin/plugin-vis-1.d: Likewise.
* ld-plugin/plugin.exp: Add list of ELF-only tests and run them if
testing on an ELF target.
---
[PATCH] Add archive support to plugin interface.
bfd/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 6/6).
* aoutx.h (aout_link_check_ar_symbols): Take new "subsbfd" reference
parameter and pass it when invoking add_archive_element callback.
(aout_link_check_archive_element): Handle substitute bfd if it
was set during add_archive_element callback in the above.
* cofflink.c (coff_link_check_ar_symbols): Take new "subsbfd" reference
parameter and pass it when invoking add_archive_element callback.
(coff_link_check_archive_element): Handle substitute bfd if it
was set during add_archive_element callback in the above.
* ecoff.c (read_ext_syms_and_strs): New function holds symbol-reading
code factored-out from ecoff_link_check_archive_element.
(reread_ext_syms_and_strs): Clear old symbols and call it.
(ecoff_link_check_archive_element): Use the above. Handle substitute
BFD if one is set by add_archive_element callback.
(ecoff_link_add_archive_symbols): Likewise allow bfd substitution.
* elflink.c (elf_link_add_archive_symbols): Likewise.
* linker.c (generic_link_check_archive_element): Likewise.
* pdp11.c (aout_link_check_ar_symbols): Take new "subsbfd" reference
parameter and pass it when invoking add_archive_element callback.
(aout_link_check_archive_element): Handle substitute bfd if it was
set during add_archive_element callback in the above.
* vms-alpha.c (alpha_vms_link_add_archive_symbols): Handle substitute
BFD if one is set by add_archive_element callback.
* xcofflink.c (xcoff_link_check_dynamic_ar_symbols): Take new "subsbfd"
reference parameter and pass it when invoking add_archive_element
callback.
(xcoff_link_check_ar_symbols): Likewise.
(xcoff_link_check_archive_element): Handle bfd substitution if it was
set by callback in the above.
include/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 6/6).
* bfdlink.h (struct_bfd_link_callbacks): Document new argument
to add_archive_element callback used to return a replacement bfd which
is to be added to the hash table in place of the original element.
ld/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 6/6).
* ldlang.c (load_symbols): Handle bfd subsitution when calling the
add_archive_element callback.
* ldmain.c (add_archive_element)[ENABLE_PLUGINS]: Offer the archive
member to the plugins and if claimed set "subsbfd" output parameter to
point to the dummy IR-only BFD.
ld/testsuite/ChangeLog:
2010-10-14 Dave Korn <dave.korn.cygwin@gmail.com>
Apply LD plugin patch series (part 6/6).
* ld-plugin/plugin-10.d: New dump test control script.
* ld-plugin/plugin-11.d: Likewise.
* ld-plugin/plugin.exp: Run them.
---
