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/* Relocate a shared object and resolve its references to other loaded objects.
Copyright (C) 1995,96,97,98,99,2000,2001 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <libintl.h>
#include <stdlib.h>
#include <unistd.h>
#include <ldsodefs.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/types.h>
#include "dynamic-link.h"
/* Statistics function. */
unsigned long int _dl_num_cache_relocations;
void
_dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
int lazy, int consider_profiling)
{
struct textrels
{
caddr_t start;
size_t len;
int prot;
struct textrels *next;
} *textrels = NULL;
/* Initialize it to make the compiler happy. */
const char *errstring = NULL;
if (l->l_relocated)
return;
/* If DT_BIND_NOW is set relocate all references in this object. We
do not do this if we are profiling, of course. */
if (!consider_profiling
&& __builtin_expect (l->l_info[DT_BIND_NOW] != NULL, 0))
lazy = 0;
if (__builtin_expect (_dl_debug_mask & DL_DEBUG_RELOC, 0))
_dl_printf ("\nrelocation processing: %s%s\n",
l->l_name[0] ? l->l_name : _dl_argv[0], lazy ? " (lazy)" : "");
/* DT_TEXTREL is now in level 2 and might phase out at some time.
But we rewrite the DT_FLAGS entry to a DT_TEXTREL entry to make
testing easier and therefore it will be available at all time. */
if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0))
{
/* Bletch. We must make read-only segments writable
long enough to relocate them. */
const ElfW(Phdr) *ph;
for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph)
if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0)
{
struct textrels *newp;
newp = (struct textrels *) alloca (sizeof (*newp));
newp->len = (((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
& ~(_dl_pagesize - 1))
- (ph->p_vaddr & ~(_dl_pagesize - 1)));
newp->start = ((ph->p_vaddr & ~(_dl_pagesize - 1))
+ (caddr_t) l->l_addr);
if (mprotect (newp->start, newp->len, PROT_READ|PROT_WRITE) < 0)
{
errstring = N_("cannot make segment writable for relocation");
call_error:
_dl_signal_error (errno, l->l_name, NULL, errstring);
}
#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
newp->prot = (PF_TO_PROT
>> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
#else
newp->prot = 0;
if (ph->p_flags & PF_R)
newp->prot |= PROT_READ;
if (ph->p_flags & PF_W)
newp->prot |= PROT_WRITE;
if (ph->p_flags & PF_X)
newp->prot |= PROT_EXEC;
#endif
newp->next = textrels;
textrels = newp;
}
}
{
/* Do the actual relocation of the object's GOT and other data. */
/* String table object symbols. */
const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
/* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
#define RESOLVE_MAP(ref, version, r_type) \
(ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \
&& elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \
? (++_dl_num_cache_relocations, \
(*ref) = l->l_lookup_cache.ret, \
l->l_lookup_cache.value) \
: ({ lookup_t _lr; \
int _tc = elf_machine_type_class (r_type); \
l->l_lookup_cache.type_class = _tc; \
l->l_lookup_cache.sym = (*ref); \
_lr = ((version) != NULL && (version)->hash != 0 \
? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \
l, (ref), scope, \
(version), _tc, 0) \
: _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), \
scope, _tc, 0)); \
l->l_lookup_cache.ret = (*ref); \
l->l_lookup_cache.value = _lr; })) \
: l)
#define RESOLVE(ref, version, r_type) \
(ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \
&& elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \
? (++_dl_num_cache_relocations, \
(*ref) = l->l_lookup_cache.ret, \
l->l_lookup_cache.value) \
: ({ lookup_t _lr; \
int _tc = elf_machine_type_class (r_type); \
l->l_lookup_cache.type_class = _tc; \
l->l_lookup_cache.sym = (*ref); \
_lr = ((version) != NULL && (version)->hash != 0 \
? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \
l, (ref), scope, \
(version), _tc, 0) \
: _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), \
scope, _tc, 0)); \
l->l_lookup_cache.ret = (*ref); \
l->l_lookup_cache.value = _lr; })) \
: l->l_addr)
#include "dynamic-link.h"
ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling);
if (__builtin_expect (consider_profiling, 0))
{
/* Allocate the array which will contain the already found
relocations. If the shared object lacks a PLT (for example
if it only contains lead function) the l_info[DT_PLTRELSZ]
will be NULL. */
if (l->l_info[DT_PLTRELSZ] == NULL)
{
errstring = N_("%s: profiler found no PLTREL in object %s\n");
fatal:
_dl_fatal_printf (errstring,
_dl_argv[0] ?: "<program name unknown>",
l->l_name);
}
l->l_reloc_result =
(ElfW(Addr) *) calloc (sizeof (ElfW(Addr)),
l->l_info[DT_PLTRELSZ]->d_un.d_val);
if (l->l_reloc_result == NULL)
{
errstring = N_("\
%s: profiler out of memory shadowing PLTREL of %s\n");
goto fatal;
}
}
}
/* Mark the object so we know this work has been done. */
l->l_relocated = 1;
/* Undo the segment protection changes. */
while (__builtin_expect (textrels != NULL, 0))
{
if (mprotect (textrels->start, textrels->len, textrels->prot) < 0)
{
errstring = N_("cannot restore segment prot after reloc");
goto call_error;
}
textrels = textrels->next;
}
}
void
internal_function
_dl_reloc_bad_type (struct link_map *map, unsigned int type, int plt)
{
/* XXX We cannot translate these messages. */
static const char msg[2][32] = { "unexpected reloc type",
"unexpected PLT reloc type" };
char msgbuf[sizeof (msg[0])];
strcpy (msgbuf, msg[plt]);
_dl_signal_error (0, map->l_name, NULL, msgbuf);
}
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