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4af6982e4c
Before to 490e6c62aa ('elf: Avoid nested functions in the loader
[BZ #27220]'), elf_get_dynamic_info() was defined twice on rtld.c: on
the first dynamic-link.h include and later within _dl_start(). The
former definition did not define DONT_USE_BOOTSTRAP_MAP and it is used
on setup_vdso() (since it is a global definition), while the former does
define DONT_USE_BOOTSTRAP_MAP and it is used on loader self-relocation.
With the commit change, the function is now included and defined once
instead of defined as a nested function. So rtld.c defines without
defining RTLD_BOOTSTRAP and it brokes at least powerpc32.
This patch fixes by moving the get-dynamic-info.h include out of
dynamic-link.h, which then the caller can corirectly set the expected
semantic by defining STATIC_PIE_BOOTSTRAP, RTLD_BOOTSTRAP, and/or
RESOLVE_MAP.
It also required to enable some asserts only for the loader bootstrap
to avoid issues when called from setup_vdso().
As a side note, this is another issues with nested functions: it is
not clear from pre-processed output (-E -dD) how the function will
be build and its semantic (since nested function will be local and
extra C defines may change it).
I checked on x86_64-linux-gnu (w/o --enable-static-pie),
i686-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu-power4,
aarch64-linux-gnu, arm-linux-gnu, sparc64-linux-gnu, and
s390x-linux-gnu.
Reviewed-by: Fangrui Song <maskray@google.com>
83 lines
2.7 KiB
C
83 lines
2.7 KiB
C
/* Support for relocating static PIE.
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Copyright (C) 2017-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#if ENABLE_STATIC_PIE
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/* Mark symbols hidden in static PIE for early self relocation to work. */
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# pragma GCC visibility push(hidden)
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#include <assert.h>
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#include <unistd.h>
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#include <ldsodefs.h>
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#include <dl-machine.h>
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#define STATIC_PIE_BOOTSTRAP
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#define RESOLVE_MAP(map, scope, sym, version, flags) map
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#include "dynamic-link.h"
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#include "get-dynamic-info.h"
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/* Relocate static executable with PIE. */
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void
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_dl_relocate_static_pie (void)
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{
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struct link_map *main_map = _dl_get_dl_main_map ();
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/* Figure out the run-time load address of static PIE. */
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main_map->l_addr = elf_machine_load_address ();
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/* Read our own dynamic section and fill in the info array. */
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main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ());
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const ElfW(Phdr) *ph, *phdr = GL(dl_phdr);
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size_t phnum = GL(dl_phnum);
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for (ph = phdr; ph < &phdr[phnum]; ++ph)
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if (ph->p_type == PT_DYNAMIC)
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{
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main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
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break;
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}
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elf_get_dynamic_info (main_map, false);
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# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
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ELF_MACHINE_BEFORE_RTLD_RELOC (main_map, main_map->l_info);
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# endif
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/* Relocate ourselves so we can do normal function calls and
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data access using the global offset table. */
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ELF_DYNAMIC_RELOCATE (main_map, NULL, 0, 0, 0);
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main_map->l_relocated = 1;
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/* Initialize _r_debug_extended. */
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struct r_debug *r = _dl_debug_initialize (0, LM_ID_BASE);
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r->r_state = RT_CONSISTENT;
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/* Set up debugging before the debugger is notified for the first
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time. */
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# ifdef ELF_MACHINE_DEBUG_SETUP
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/* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
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ELF_MACHINE_DEBUG_SETUP (main_map, r);
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# else
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if (main_map->l_info[DT_DEBUG] != NULL)
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/* There is a DT_DEBUG entry in the dynamic section. Fill it in
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with the run-time address of the r_debug structure */
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main_map->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
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# endif
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}
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#endif
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