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4dca2d3a7b
On hppa, a function pointer returned by la_symbind is actually a function
descriptor has the plabel bit set (bit 30). This must be cleared to get
the actual address of the descriptor. If the descriptor has been bound,
the first word of the descriptor is the physical address of theA function,
otherwise, the first word of the descriptor points to a trampoline in the
PLT.
This patch also adds a workaround on tests because on hppa (and it seems
to be the only ABI I have see it), some shared library adds a dynamic PLT
relocation to am empty symbol name:
$ readelf -r elf/tst-audit25mod1.so
[...]
Relocation section '.rela.plt' at offset 0x464 contains 6 entries:
Offset Info Type Sym.Value Sym. Name + Addend
00002008 00000081 R_PARISC_IPLT 508
[...]
It breaks some assumptions on the test, where a symbol with an empty
name ("") is passed on la_symbind.
Checked on x86_64-linux-gnu and hppa-linux-gnu.
(cherry picked from commit 9e94f57484)
89 lines
3.2 KiB
C
89 lines
3.2 KiB
C
/* Configuration of lookup functions.
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Copyright (C) 2000-2021 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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#define ELF_FUNCTION_PTR_IS_SPECIAL
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#define DL_UNMAP_IS_SPECIAL
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#include <dl-fptr.h>
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/* Forward declaration. */
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struct link_map;
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void *_dl_symbol_address (struct link_map *map, const ElfW(Sym) *ref);
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rtld_hidden_proto (_dl_symbol_address)
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#define DL_SYMBOL_ADDRESS(map, ref) _dl_symbol_address(map, ref)
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Elf32_Addr _dl_lookup_address (const void *address);
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rtld_hidden_proto (_dl_lookup_address)
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#define DL_LOOKUP_ADDRESS(addr) _dl_lookup_address ((const void *) addr)
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void attribute_hidden _dl_unmap (struct link_map *map);
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#define DL_UNMAP(map) _dl_unmap (map)
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#define DL_DT_FUNCTION_ADDRESS(map, start, attr, addr) \
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attr volatile unsigned int fptr[2]; \
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/* The test for "start & 2" below is to accommodate old binaries which \
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violated the ELF ABI by pointing DT_INIT and DT_FINI at a function \
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descriptor. */ \
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if ((ElfW(Addr)) (start) & 2) \
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addr = (ElfW(Addr)) start; \
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else \
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{ \
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fptr[0] = (unsigned int) (start); \
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fptr[1] = (map)->l_info[DT_PLTGOT]->d_un.d_ptr; \
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/* Set bit 30 to indicate to $$dyncall that this is a PLABEL. */ \
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addr = (ElfW(Addr))((unsigned int)fptr | 2); \
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} \
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#define DL_CALL_DT_INIT(map, start, argc, argv, env) \
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{ \
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ElfW(Addr) addr; \
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DL_DT_FUNCTION_ADDRESS(map, start, , addr) \
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dl_init_t init = (dl_init_t) addr; \
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init (argc, argv, env); \
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}
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#define DL_CALL_DT_FINI(map, start) \
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{ \
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ElfW(Addr) addr; \
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DL_DT_FUNCTION_ADDRESS(map, start, , addr) \
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fini_t fini = (fini_t) addr; \
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fini (); \
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}
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/* The type of the return value of fixup/profile_fixup */
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#define DL_FIXUP_VALUE_TYPE struct fdesc
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/* Construct a fixup value from the address and linkmap */
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#define DL_FIXUP_MAKE_VALUE(map, addr) \
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(map) ? ((struct fdesc) { (addr), (map)->l_info[DT_PLTGOT]->d_un.d_ptr }) \
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: ((struct fdesc) { 0, 0 })
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/* Extract the code address from a fixup value */
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#define DL_FIXUP_VALUE_CODE_ADDR(value) ((value).ip)
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#define DL_FIXUP_VALUE_ADDR(value) ((uintptr_t) &(value))
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/* Clear the plabel bit to get the actual address of the descriptor. */
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#define DL_FIXUP_ADDR_VALUE(addr) \
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(*(DL_FIXUP_VALUE_TYPE *) ((uintptr_t) (addr) & ~2))
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#define DL_FIXUP_BINDNOW_ADDR_VALUE(addr) (addr)
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#define DL_FIXUP_BINDNOW_RELOC(value, new_value, st_value) \
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*(value) = *(DL_FIXUP_VALUE_TYPE *) ((uintptr_t) (new_value) & ~2)
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