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207 |
jeremybenn |
/* 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 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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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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/param.h>
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#include <sys/types.h>
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#include "dynamic-link.h"
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/* Statistics function. */
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unsigned long int _dl_num_cache_relocations;
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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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struct textrels
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{
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caddr_t start;
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size_t len;
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int prot;
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struct textrels *next;
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} *textrels = NULL;
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/* Initialize it to make the compiler happy. */
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const char *errstring = NULL;
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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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/* 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 a DT_TEXTREL entry to make
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testing easier and 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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/* 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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struct textrels *newp;
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newp = (struct textrels *) alloca (sizeof (*newp));
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newp->len = (((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
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& ~(_dl_pagesize - 1))
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- (ph->p_vaddr & ~(_dl_pagesize - 1)));
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newp->start = ((ph->p_vaddr & ~(_dl_pagesize - 1))
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+ (caddr_t) l->l_addr);
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if (mprotect (newp->start, newp->len, PROT_READ|PROT_WRITE) < 0)
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{
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errstring = N_("cannot make segment writable for relocation");
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call_error:
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_dl_signal_error (errno, l->l_name, NULL, errstring);
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}
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#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
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newp->prot = (PF_TO_PROT
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>> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
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#else
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newp->prot = 0;
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if (ph->p_flags & PF_R)
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newp->prot |= PROT_READ;
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if (ph->p_flags & PF_W)
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newp->prot |= PROT_WRITE;
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if (ph->p_flags & PF_X)
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newp->prot |= PROT_EXEC;
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#endif
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newp->next = textrels;
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textrels = newp;
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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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/* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
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#define RESOLVE_MAP(ref, version, r_type, scope) \
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(ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
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? ((__builtin_expect ((*ref) == map->l_lookup_cache.sym, 0) \
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&& elf_machine_type_class (r_type) == map->l_lookup_cache.type_class)\
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? (++_dl_num_cache_relocations, \
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(*ref) = map->l_lookup_cache.ret, \
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map->l_lookup_cache.value) \
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: ({ lookup_t _lr; \
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int _tc = elf_machine_type_class (r_type); \
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map->l_lookup_cache.type_class = _tc; \
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map->l_lookup_cache.sym = (*ref); \
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_lr = ((version) != NULL && (version)->hash != 0 \
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? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \
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map, (ref), scope, \
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(version), _tc, 0) \
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: _dl_lookup_symbol (strtab + (*ref)->st_name, map, (ref),\
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scope, _tc, 0)); \
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map->l_lookup_cache.ret = (*ref); \
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map->l_lookup_cache.value = _lr; })) \
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: map)
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#define RESOLVE(ref, version, r_type, scope) \
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(ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
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? ((__builtin_expect ((*ref) == map->l_lookup_cache.sym, 0) \
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&& elf_machine_type_class (r_type) == map->l_lookup_cache.type_class)\
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? (++_dl_num_cache_relocations, \
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(*ref) = map->l_lookup_cache.ret, \
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map->l_lookup_cache.value) \
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: ({ lookup_t _lr; \
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int _tc = elf_machine_type_class (r_type); \
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map->l_lookup_cache.type_class = _tc; \
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map->l_lookup_cache.sym = (*ref); \
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_lr = ((version) != NULL && (version)->hash != 0 \
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? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \
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map, (ref), scope, \
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(version), _tc, 0) \
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: _dl_lookup_symbol (strtab + (*ref)->st_name, map, (ref),\
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scope, _tc, 0)); \
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map->l_lookup_cache.ret = (*ref); \
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map->l_lookup_cache.value = _lr; })) \
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: map->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 (consider_profiling, 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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{
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errstring = N_("%s: profiler found no PLTREL in object %s\n");
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fatal:
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_dl_fatal_printf (errstring,
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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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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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{
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errstring = N_("\
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%s: profiler out of memory shadowing PLTREL of %s\n");
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goto fatal;
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}
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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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/* Undo the segment protection changes. */
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while (__builtin_expect (textrels != NULL, 0))
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{
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if (mprotect (textrels->start, textrels->len, textrels->prot) < 0)
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{
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errstring = N_("cannot restore segment prot after reloc");
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goto call_error;
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}
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textrels = textrels->next;
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}
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}
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#include <machine/dl-machine.h>
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void
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internal_function
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_dl_reloc_bad_type (struct link_map *map, unsigned int type, int plt)
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{
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/* XXX We cannot translate these messages. */
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static const char msg[2][32] = { "unexpected reloc type",
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"unexpected PLT reloc type" };
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char msgbuf[sizeof (msg[0])];
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strcpy (msgbuf, msg[plt]);
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_dl_signal_error (0, map->l_name, NULL, msgbuf);
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}
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