glibc/elf/tst-filterobj-aux.c

/* Auxiliary filter object.
   Contains symbols to be resolved in filtee, and one which doesn't.

   Copyright (C) 2020 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include "tst-filterobj-filtee.h"

/* We never want to see the output of the auxiliary object.  */
const char *get_text (void)
{
  return "Hello from auxiliary filter object (FAIL)";
}

/* The filtee doesn't implement this symbol, so this should resolve.  */
const char *get_text2 (void)
{
  return "Hello from auxiliary filter object (PASS)";
}
elf: Allow dlopen of filter object to work [BZ #16272] There are two fixes that are needed to be able to dlopen filter objects. First _dl_map_object_deps cannot assume that map will be at the beginning of l_searchlist.r_list[], as filtees are inserted before map. Secondly dl_open_worker needs to ensure that filtees get relocated. In _dl_map_object_deps: * avoiding removing relocation dependencies of map by setting l_reserved to 0 and otherwise processing the rest of the search list. * ensure that map remains at the beginning of l_initfini - the list of things that need initialisation (and destruction). Do this by splitting the copy up. This may not be required, but matches the initialization order without dlopen. Modify dl_open_worker to relocate the objects in new->l_inifini. new->l_initfini is constructed in _dl_map_object_deps, and lists the objects that need initialization and destruction. Originally the list of objects in new->l_next are relocated. All of these objects should also be included in new->l_initfini (both lists are populated with dependencies in _dl_map_object_deps). We can't use new->l_prev to pick up filtees, as during a recursive dlopen from an interposed malloc call, l->prev can contain objects that are not ready for relocation. Add tests to verify that symbols resolve to the filtee implementation when auxiliary and filter objects are used, both as a normal link and when dlopen'd. Tested by running the testsuite on x86_64. 2020-02-12 17:28:15 +00:00			`/* Auxiliary filter object.`
			`Contains symbols to be resolved in filtee, and one which doesn't.`

			`Copyright (C) 2020 Free Software Foundation, Inc.`
			`This file is part of the GNU C Library.`

			`The GNU C Library is free software; you can redistribute it and/or`
			`modify it under the terms of the GNU Lesser General Public`
			`License as published by the Free Software Foundation; either`
			`version 2.1 of the License, or (at your option) any later version.`

			`The GNU C Library is distributed in the hope that it will be useful,`
			`but WITHOUT ANY WARRANTY; without even the implied warranty of`
			`MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU`
			`Lesser General Public License for more details.`

			`You should have received a copy of the GNU Lesser General Public`
			`License along with the GNU C Library; if not, see`
			`<https://www.gnu.org/licenses/>. */`

			`#include "tst-filterobj-filtee.h"`

			`/* We never want to see the output of the auxiliary object. */`
			`const char *get_text (void)`
			`{`
			`return "Hello from auxiliary filter object (FAIL)";`
			`}`

			`/* The filtee doesn't implement this symbol, so this should resolve. */`
			`const char *get_text2 (void)`
			`{`
			`return "Hello from auxiliary filter object (PASS)";`
			`}`