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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>
205 lines
8.3 KiB
C
205 lines
8.3 KiB
C
/* Inline functions for dynamic linking.
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Copyright (C) 1995-2021 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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/* This macro is used as a callback from elf_machine_rel{a,} when a
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static TLS reloc is about to be performed. Since (in dl-load.c) we
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permit dynamic loading of objects that might use such relocs, we
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have to check whether each use is actually doable. If the object
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whose TLS segment the reference resolves to was allocated space in
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the static TLS block at startup, then it's ok. Otherwise, we make
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an attempt to allocate it in surplus space on the fly. If that
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can't be done, we fall back to the error that DF_STATIC_TLS is
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intended to produce. */
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#define HAVE_STATIC_TLS(map, sym_map) \
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(__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET \
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&& ((sym_map)->l_tls_offset \
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!= FORCED_DYNAMIC_TLS_OFFSET), 1))
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#define CHECK_STATIC_TLS(map, sym_map) \
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do { \
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if (!HAVE_STATIC_TLS (map, sym_map)) \
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_dl_allocate_static_tls (sym_map); \
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} while (0)
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#define TRY_STATIC_TLS(map, sym_map) \
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(__builtin_expect ((sym_map)->l_tls_offset \
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!= FORCED_DYNAMIC_TLS_OFFSET, 1) \
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&& (__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET, 1) \
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|| _dl_try_allocate_static_tls (sym_map, true) == 0))
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int _dl_try_allocate_static_tls (struct link_map *map, bool optional)
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attribute_hidden;
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#include <elf.h>
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#ifdef RESOLVE_MAP
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/* We pass reloc_addr as a pointer to void, as opposed to a pointer to
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ElfW(Addr), because not all architectures can assume that the
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relocated address is properly aligned, whereas the compiler is
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entitled to assume that a pointer to a type is properly aligned for
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the type. Even if we cast the pointer back to some other type with
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less strict alignment requirements, the compiler might still
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remember that the pointer was originally more aligned, thereby
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optimizing away alignment tests or using word instructions for
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copying memory, breaking the very code written to handle the
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unaligned cases. */
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# if ! ELF_MACHINE_NO_REL
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static inline void __attribute__((always_inline))
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elf_machine_rel (struct link_map *map, struct r_scope_elem *scope[],
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const ElfW(Rel) *reloc, const ElfW(Sym) *sym,
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const struct r_found_version *version,
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void *const reloc_addr, int skip_ifunc);
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static inline void __attribute__((always_inline))
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elf_machine_rel_relative (ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
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void *const reloc_addr);
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# endif
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# if ! ELF_MACHINE_NO_RELA
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static inline void __attribute__((always_inline))
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elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
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const ElfW(Rela) *reloc, const ElfW(Sym) *sym,
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const struct r_found_version *version, void *const reloc_addr,
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int skip_ifunc);
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static inline void __attribute__((always_inline))
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elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
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void *const reloc_addr);
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# endif
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# if ELF_MACHINE_NO_RELA || defined ELF_MACHINE_PLT_REL
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static inline void __attribute__((always_inline))
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elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
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ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
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int skip_ifunc);
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# else
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static inline void __attribute__((always_inline))
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elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
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ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
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int skip_ifunc);
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# endif
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#endif
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#include <dl-machine.h>
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#ifdef RESOLVE_MAP
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# if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP
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# define ELF_DURING_STARTUP (1)
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# else
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# define ELF_DURING_STARTUP (0)
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# endif
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/* Get the definitions of `elf_dynamic_do_rel' and `elf_dynamic_do_rela'.
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These functions are almost identical, so we use cpp magic to avoid
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duplicating their code. It cannot be done in a more general function
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because we must be able to completely inline. */
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/* On some machines, notably SPARC, DT_REL* includes DT_JMPREL in its
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range. Note that according to the ELF spec, this is completely legal!
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We are guarenteed that we have one of three situations. Either DT_JMPREL
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comes immediately after DT_REL*, or there is overlap and DT_JMPREL
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consumes precisely the very end of the DT_REL*, or DT_JMPREL and DT_REL*
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are completely separate and there is a gap between them. */
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# define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, scope, do_lazy, skip_ifunc, test_rel) \
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do { \
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struct { ElfW(Addr) start, size; \
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__typeof (((ElfW(Dyn) *) 0)->d_un.d_val) nrelative; int lazy; } \
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ranges[2] = { { 0, 0, 0, 0 }, { 0, 0, 0, 0 } }; \
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\
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if ((map)->l_info[DT_##RELOC]) \
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{ \
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ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]); \
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ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val; \
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if (map->l_info[VERSYMIDX (DT_##RELOC##COUNT)] != NULL) \
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ranges[0].nrelative \
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= map->l_info[VERSYMIDX (DT_##RELOC##COUNT)]->d_un.d_val; \
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} \
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if ((map)->l_info[DT_PLTREL] \
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&& (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
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{ \
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ElfW(Addr) start = D_PTR ((map), l_info[DT_JMPREL]); \
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ElfW(Addr) size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val; \
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\
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if (ranges[0].start + ranges[0].size == (start + size)) \
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ranges[0].size -= size; \
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if (ELF_DURING_STARTUP \
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|| (!(do_lazy) \
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&& (ranges[0].start + ranges[0].size) == start)) \
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{ \
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/* Combine processing the sections. */ \
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ranges[0].size += size; \
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} \
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else \
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{ \
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ranges[1].start = start; \
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ranges[1].size = size; \
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ranges[1].lazy = (do_lazy); \
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} \
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} \
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\
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if (ELF_DURING_STARTUP) \
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elf_dynamic_do_##reloc ((map), scope, ranges[0].start, ranges[0].size, \
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ranges[0].nrelative, 0, skip_ifunc); \
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else \
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{ \
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int ranges_index; \
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for (ranges_index = 0; ranges_index < 2; ++ranges_index) \
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elf_dynamic_do_##reloc ((map), scope, \
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ranges[ranges_index].start, \
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ranges[ranges_index].size, \
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ranges[ranges_index].nrelative, \
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ranges[ranges_index].lazy, \
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skip_ifunc); \
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} \
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} while (0)
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# if ELF_MACHINE_NO_REL || ELF_MACHINE_NO_RELA
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# define _ELF_CHECK_REL 0
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# else
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# define _ELF_CHECK_REL 1
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# endif
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# if ! ELF_MACHINE_NO_REL
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# include "do-rel.h"
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# define ELF_DYNAMIC_DO_REL(map, scope, lazy, skip_ifunc) \
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_ELF_DYNAMIC_DO_RELOC (REL, Rel, map, scope, lazy, skip_ifunc, _ELF_CHECK_REL)
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# else
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# define ELF_DYNAMIC_DO_REL(map, scope, lazy, skip_ifunc) /* Nothing to do. */
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# endif
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# if ! ELF_MACHINE_NO_RELA
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# define DO_RELA
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# include "do-rel.h"
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# define ELF_DYNAMIC_DO_RELA(map, scope, lazy, skip_ifunc) \
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_ELF_DYNAMIC_DO_RELOC (RELA, Rela, map, scope, lazy, skip_ifunc, _ELF_CHECK_REL)
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# else
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# define ELF_DYNAMIC_DO_RELA(map, scope, lazy, skip_ifunc) /* Nothing to do. */
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# endif
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/* This can't just be an inline function because GCC is too dumb
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to inline functions containing inlines themselves. */
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# define ELF_DYNAMIC_RELOCATE(map, scope, lazy, consider_profile, skip_ifunc) \
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do { \
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int edr_lazy = elf_machine_runtime_setup ((map), (scope), (lazy), \
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(consider_profile)); \
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ELF_DYNAMIC_DO_REL ((map), (scope), edr_lazy, skip_ifunc); \
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ELF_DYNAMIC_DO_RELA ((map), (scope), edr_lazy, skip_ifunc); \
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} while (0)
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#endif
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