186 lines
6.4 KiB
C
186 lines
6.4 KiB
C
/* Relocate a shared object and resolve its references to other loaded objects.
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Copyright (C) 1995,96,97,98,99,2000,2001 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <errno.h>
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#include <libintl.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <ldsodefs.h>
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#include <sys/mman.h>
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#include <sys/types.h>
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#include "dynamic-link.h"
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void
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_dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
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int lazy, int consider_profiling)
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{
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if (l->l_relocated)
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return;
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/* If DT_BIND_NOW is set relocate all references in this object. We
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do not do this if we are profiling, of course. */
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if (!consider_profiling
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&& __builtin_expect (l->l_info[DT_BIND_NOW] != NULL, 0))
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lazy = 0;
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if (__builtin_expect (_dl_debug_mask & DL_DEBUG_RELOC, 0))
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_dl_printf ("\nrelocation processing: %s%s\n",
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l->l_name[0] ? l->l_name : _dl_argv[0], lazy ? " (lazy)" : "");
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if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0))
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{
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/* Bletch. We must make read-only segments writable
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long enough to relocate them. */
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const ElfW(Phdr) *ph;
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for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
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if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
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{
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caddr_t mapstart = ((caddr_t) l->l_addr +
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(ph->p_vaddr & ~(_dl_pagesize - 1)));
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caddr_t mapend = ((caddr_t) l->l_addr +
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((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
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& ~(_dl_pagesize - 1)));
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if (__builtin_expect (__mprotect (mapstart, mapend - mapstart,
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PROT_READ|PROT_WRITE), 0) < 0)
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_dl_signal_error (errno, l->l_name, N_("\
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cannot make segment writable for relocation"));
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}
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}
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{
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/* Do the actual relocation of the object's GOT and other data. */
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/* String table object symbols. */
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const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
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/* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
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#define RESOLVE_MAP(ref, version, flags) \
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(ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
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? ((version) != NULL && (version)->hash != 0 \
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? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, l, (ref), \
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scope, (version), (flags), 0) \
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: _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), scope, \
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(flags), 0)) \
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: l)
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#define RESOLVE(ref, version, flags) \
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(ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
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? ((version) != NULL && (version)->hash != 0 \
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? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, l, (ref), \
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scope, (version), (flags), 0) \
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: _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), scope, \
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(flags), 0)) \
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: l->l_addr)
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#include "dynamic-link.h"
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ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling);
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if (__builtin_expect (_dl_profile != NULL, 0))
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{
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/* Allocate the array which will contain the already found
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relocations. If the shared object lacks a PLT (for example
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if it only contains lead function) the l_info[DT_PLTRELSZ]
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will be NULL. */
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if (l->l_info[DT_PLTRELSZ] == NULL)
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_dl_fatal_printf ("%s: profiler found no PLTREL in object %s\n",
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_dl_argv[0] ?: "<program name unknown>",
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l->l_name);
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l->l_reloc_result =
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(ElfW(Addr) *) calloc (sizeof (ElfW(Addr)),
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l->l_info[DT_PLTRELSZ]->d_un.d_val);
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if (l->l_reloc_result == NULL)
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_dl_fatal_printf ("\
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%s: profiler out of memory shadowing PLTREL of %s\n",
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_dl_argv[0] ?: "<program name unknown>",
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l->l_name);
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}
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}
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/* Mark the object so we know this work has been done. */
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l->l_relocated = 1;
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/* DT_TEXTREL is now in level 2 and might phase out at some time.
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But we rewrite the DT_FLAGS entry to make testing easier and
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therefore it will be available at all time. */
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if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0))
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{
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/* Undo the protection change we made before relocating. */
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const ElfW(Phdr) *ph;
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for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
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if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
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{
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caddr_t mapstart = ((caddr_t) l->l_addr +
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(ph->p_vaddr & ~(_dl_pagesize - 1)));
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caddr_t mapend = ((caddr_t) l->l_addr +
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((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
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& ~(_dl_pagesize - 1)));
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extern unsigned char _dl_pf_to_prot[8];
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int prot;
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if ((PF_R | PF_W | PF_X) == 7
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&& (PROT_READ | PROT_WRITE | PROT_EXEC) == 7)
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prot = _dl_pf_to_prot[ph->p_flags & (PF_R | PF_X)];
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else
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{
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prot = 0;
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if (ph->p_flags & PF_R)
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prot |= PROT_READ;
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if (ph->p_flags & PF_X)
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prot |= PROT_EXEC;
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}
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if (__builtin_expect (__mprotect (mapstart, mapend - mapstart,
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prot), 0) < 0)
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_dl_signal_error (errno, l->l_name,
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N_("can't restore segment prot after reloc"));
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#ifdef CLEAR_CACHE
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CLEAR_CACHE (mapstart, mapend);
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#endif
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}
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}
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}
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#include "../stdio-common/_itoa.h"
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#define DIGIT(b) _itoa_lower_digits[(b) & 0xf];
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void
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internal_function
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_dl_reloc_bad_type (struct link_map *map, uint_fast8_t type, int plt)
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{
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extern const char _itoa_lower_digits[];
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if (plt)
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{
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/* XXX We cannot translate the message. */
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static char msg[] = "unexpected PLT reloc type 0x??";
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msg[sizeof msg - 3] = DIGIT(type >> 4);
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msg[sizeof msg - 2] = DIGIT(type);
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_dl_signal_error (0, map->l_name, msg);
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}
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else
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{
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/* XXX We cannot translate the message. */
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static char msg[] = "unexpected reloc type 0x??";
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msg[sizeof msg - 3] = DIGIT(type >> 4);
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msg[sizeof msg - 2] = DIGIT(type);
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_dl_signal_error (0, map->l_name, msg);
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}
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}
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