glibc/elf/dl-debug-symbols.S

/* Define symbols used to communicate dynamic linker state to the
   debugger at runtime.
   Copyright (C) 2021 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 <rtld-sizes.h>

/* Define 2 symbols, _r_debug_extended and _r_debug, which is an alias
   of _r_debug_extended, but with the size of struct r_debug.  */

	.globl	_r_debug
	.type	_r_debug, %object
	.size	_r_debug, R_DEBUG_SIZE
	.hidden	_r_debug_extended
	.globl	_r_debug_extended
	.type	_r_debug_extended, %object
	.size	_r_debug_extended, R_DEBUG_EXTENDED_SIZE
	.section .bss
	.balign	R_DEBUG_EXTENDED_ALIGN
_r_debug:
_r_debug_extended:
	.zero	R_DEBUG_EXTENDED_SIZE
Extend struct r_debug to support multiple namespaces [BZ #15971] Glibc does not provide an interface for debugger to access libraries loaded in multiple namespaces via dlmopen. The current rtld-debugger interface is described in the file: elf/rtld-debugger-interface.txt under the "Standard debugger interface" heading. This interface only provides access to the first link-map (LM_ID_BASE). 1. Bump r_version to 2 when multiple namespaces are used. This triggers the GDB bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28236 2. Add struct r_debug_extended to extend struct r_debug into a linked-list, where each element correlates to an unique namespace. 3. Initialize the r_debug_extended structure. Bump r_version to 2 for the new namespace and add the new namespace to the namespace linked list. 4. Add _dl_debug_update to return the address of struct r_debug' of a namespace. 5. Add a hidden symbol, _r_debug_extended, for struct r_debug_extended. 6. Provide the symbol, _r_debug, with size of struct r_debug, as an alias of _r_debug_extended, for programs which reference _r_debug. This fixes BZ #15971. Reviewed-by: Florian Weimer <fweimer@redhat.com> 2021-08-18 10:35:48 +08:00			`/* Define symbols used to communicate dynamic linker state to the`
			`debugger at runtime.`
			`Copyright (C) 2021 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 <rtld-sizes.h>`

			`/* Define 2 symbols, _r_debug_extended and _r_debug, which is an alias`
			`of _r_debug_extended, but with the size of struct r_debug. */`

			`.globl _r_debug`
			`.type _r_debug, %object`
			`.size _r_debug, R_DEBUG_SIZE`
			`.hidden _r_debug_extended`
			`.globl _r_debug_extended`
			`.type _r_debug_extended, %object`
			`.size _r_debug_extended, R_DEBUG_EXTENDED_SIZE`
			`.section .bss`
			`.balign R_DEBUG_EXTENDED_ALIGN`
			`_r_debug:`
			`_r_debug_extended:`
			`.zero R_DEBUG_EXTENDED_SIZE`