[patch ld]: Close BFDs before linker-plugin's atexit routine is called

[Kai Tietz]

2011/2/14 Alan Modra <amodra@gmail.com>:
> On Mon, Feb 14, 2011 at 10:21:58AM +0100, Kai Tietz wrote:
>> 2011/2/14 Kai Tietz <ktietz70@googlemail.com>:
>> > 2011/2/14 Alan Modra <amodra@gmail.com>:
>> >> On Wed, Feb 09, 2011 at 07:51:58PM +0100, Kai Tietz wrote:
>> >>> Hello,
>> >>>
>> >>> This is patch addresses the unlink call when lto linker-plugin is
>> >>> used.  As windows
>> >>> native doesn't support to unlink still opened files, it fails to do so
>> >>> as file-descriptors
>> >>> of bfds aren't closed before atexit routine of plugin gets called.
>> >>>
>> >>> 2011-02-09  Kai Tietz
>> >>>
>> >>>       * ldmain.c (remove_output): Set output_bfd
>> >>>       of link_info to nil and close all cached bfds.
>> >>>       (main): Close output_bfd of link_info and set
>> >>>       it to nil. Additionally close all cached bfds.
>> >
>> > Hi Alan,
>> >
>> >> The fact that you need to patch three places to fix one problem
>> >> says to me that this isn't the best fix..
>> > Well, here I am not that sure about. I thought about fixing it just
>> > within the atexit-handler of plugin, but well, next one trying to
>> > opearate on files in a similar way, will have the same issues again. I
>> > think it is simply bad style to exit a program without even try to
>> > cleanup  opened file descriptors and used memory. This could even help
>> > to use tools like valgrind on ld ...
>
> Yes, it's true that closing the files really belongs in ld itself.
>
>> >>  Does a single
>> >> bfd_cache_close_all at the start of plugin_call_cleanup fix your
>> >> problem?
>> > Yes, it does.
>>
>> I reworked patch a bit. It takes care that in ldmain's local
>> atexit-handler BFDs are closed, and that for case of plugin the bfds
>> getting closed before it tries to unlink
>> files.
>
> Better, but this is what I'm about to commit.
>
>        * ldmain.c (remove_output): Rename to..
>        (ld_cleanup): ..this. Call bfd_cache_close_all and plugin_call_cleanup.
>        (main): Adjust.
>        * plugin.c (plugin_call_cleanup): Make global.
>        (plugin_load_plugins): Don't register plugin_call_cleanup with xatexit.
>        * plugin.h (plugin_call_cleanup): Declare.
>
> Index: ld/ldmain.c
> ===================================================================
> RCS file: /cvs/src/src/ld/ldmain.c,v
> retrieving revision 1.148
> diff -u -p -r1.148 ldmain.c
> --- ld/ldmain.c 14 Jan 2011 12:37:17 -0000      1.148
> +++ ld/ldmain.c 14 Feb 2011 07:57:25 -0000
> @@ -174,15 +174,14 @@ static struct bfd_link_callbacks link_ca
>  struct bfd_link_info link_info;
>
>  static void
> -remove_output (void)
> +ld_cleanup (void)
>  {
> -  if (output_filename)
> -    {
> -      if (link_info.output_bfd)
> -       bfd_cache_close (link_info.output_bfd);
> -      if (delete_output_file_on_failure)
> -       unlink_if_ordinary (output_filename);
> -    }
> +  bfd_cache_close_all ();
> +#ifdef ENABLE_PLUGINS
> +  plugin_call_cleanup ();
> +#endif
> +  if (output_filename && delete_output_file_on_failure)
> +    unlink_if_ordinary (output_filename);
>  }
>
>  int
> @@ -211,7 +210,7 @@ main (int argc, char **argv)
>
>   bfd_set_error_program_name (program_name);
>
> -  xatexit (remove_output);
> +  xatexit (ld_cleanup);
>
>   /* Set up the sysroot directory.  */
>   ld_sysroot = get_sysroot (argc, argv);
> Index: ld/plugin.c
> ===================================================================
> RCS file: /cvs/src/src/ld/plugin.c,v
> retrieving revision 1.22
> diff -u -p -r1.22 plugin.c
> --- ld/plugin.c 22 Jan 2011 10:16:29 -0000      1.22
> +++ ld/plugin.c 14 Feb 2011 07:57:26 -0000
> @@ -108,9 +108,6 @@ static bfd_boolean no_more_claiming = FA
>    TRUE is returned from the hook.  */
>  static bfd_boolean plugin_cached_allow_multiple_defs = FALSE;
>
> -/* Call 'cleanup' hook for all plugins at exit.  */
> -static void plugin_call_cleanup (void);
> -
>  /* List of tags to set in the constant leading part of the tv array. */
>  static const enum ld_plugin_tag tv_header_tags[] =
>  {
> @@ -721,8 +723,6 @@ plugin_load_plugins (void)
>   if (!curplug)
>     return 0;
>
> -  xatexit (plugin_call_cleanup);
> -
>   /* First pass over plugins to find max # args needed so that we
>      can size and allocate the tv array.  */
>   while (curplug)
> @@ -820,7 +820,7 @@ plugin_call_all_symbols_read (void)
>  }
>
>  /* Call 'cleanup' hook for all plugins at exit.  */
> -static void
> +void
>  plugin_call_cleanup (void)
>  {
>   plugin_t *curplug = plugins_list;
> Index: ld/plugin.h
> ===================================================================
> RCS file: /cvs/src/src/ld/plugin.h,v
> retrieving revision 1.5
> diff -u -p -r1.5 plugin.h
> --- ld/plugin.h 6 Dec 2010 12:44:51 -0000       1.5
> +++ ld/plugin.h 14 Feb 2011 07:57:26 -0000
> @@ -50,6 +50,9 @@ extern int plugin_call_claim_file (const
>  /* Call 'all symbols read' hook for all plugins.  */
>  extern int plugin_call_all_symbols_read (void);
>
> +/* Call 'cleanup' hook for all plugins at exit.  */
> +extern void plugin_call_cleanup (void);
> +
>  /* Generate a dummy BFD to represent an IR file, for any callers of
>    plugin_call_claim_file to use as the handle in the ld_plugin_input_file
>    struct that they build to pass in.  The BFD is initially writable, so
>
> --
> Alan Modra
> Australia Development Lab, IBM
>

Yes, looks good and passes my tests.

Thanks,
Kai