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glibc/elf/dl-addr.c
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/* Locate the shared object symbol nearest a given address. | |
Copyright (C) 1996-2004, 2005 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 <dlfcn.h> | |
#include <stddef.h> | |
#include <ldsodefs.h> | |
int | |
internal_function | |
_dl_addr (const void *address, Dl_info *info, | |
struct link_map **mapp, const ElfW(Sym) **symbolp) | |
{ | |
const ElfW(Addr) addr = DL_LOOKUP_ADDRESS (address); | |
/* Protect against concurrent loads and unloads. */ | |
__rtld_lock_lock_recursive (GL(dl_load_lock)); | |
/* Find the highest-addressed object that ADDRESS is not below. */ | |
struct link_map *match = NULL; | |
for (Lmid_t ns = 0; ns < DL_NNS; ++ns) | |
for (struct link_map *l = GL(dl_ns)[ns]._ns_loaded; l; l = l->l_next) | |
if (addr >= l->l_map_start && addr < l->l_map_end) | |
{ | |
/* We know ADDRESS lies within L if in any shared object. | |
Make sure it isn't past the end of L's segments. */ | |
size_t n = l->l_phnum; | |
if (n > 0) | |
{ | |
do | |
--n; | |
while (l->l_phdr[n].p_type != PT_LOAD); | |
if (addr >= (l->l_addr + | |
l->l_phdr[n].p_vaddr + l->l_phdr[n].p_memsz)) | |
/* Off the end of the highest-addressed shared object. */ | |
continue; | |
} | |
match = l; | |
break; | |
} | |
int result = 0; | |
if (match != NULL) | |
{ | |
/* Now we know what object the address lies in. */ | |
info->dli_fname = match->l_name; | |
info->dli_fbase = (void *) match->l_map_start; | |
/* If this is the main program the information is incomplete. */ | |
if (__builtin_expect (match->l_name[0], 'a') == '\0' | |
&& match->l_type == lt_executable) | |
info->dli_fname = _dl_argv[0]; | |
const ElfW(Sym) *symtab | |
= (const ElfW(Sym) *) D_PTR (match, l_info[DT_SYMTAB]); | |
const char *strtab = (const char *) D_PTR (match, l_info[DT_STRTAB]); | |
ElfW(Word) strtabsize = match->l_info[DT_STRSZ]->d_un.d_val; | |
const ElfW(Sym) *symtabend; | |
if (match->l_info[DT_HASH] != NULL) | |
symtabend = (symtab | |
+ ((Elf_Symndx *) D_PTR (match, l_info[DT_HASH]))[1]); | |
else | |
/* There is no direct way to determine the number of symbols in the | |
dynamic symbol table and no hash table is present. The ELF | |
binary is ill-formed but what shall we do? Use the beginning of | |
the string table which generally follows the symbol table. */ | |
symtabend = (const ElfW(Sym) *) strtab; | |
/* We assume that the string table follows the symbol table, | |
because there is no way in ELF to know the size of the | |
dynamic symbol table!! */ | |
const ElfW(Sym) *matchsym; | |
for (matchsym = NULL; (void *) symtab < (void *) symtabend; ++symtab) | |
if (addr >= match->l_addr + symtab->st_value | |
#if defined USE_TLS | |
&& ELFW(ST_TYPE) (symtab->st_info) != STT_TLS | |
#endif | |
&& ((symtab->st_size == 0 | |
&& addr == match->l_addr + symtab->st_value) | |
|| addr < match->l_addr + symtab->st_value + symtab->st_size) | |
&& symtab->st_name < strtabsize | |
&& (matchsym == NULL || matchsym->st_value < symtab->st_value) | |
&& (ELFW(ST_BIND) (symtab->st_info) == STB_GLOBAL | |
|| ELFW(ST_BIND) (symtab->st_info) == STB_WEAK)) | |
matchsym = (ElfW(Sym) *) symtab; | |
if (mapp) | |
*mapp = match; | |
if (symbolp) | |
*symbolp = matchsym; | |
if (matchsym) | |
{ | |
/* We found a symbol close by. Fill in its name and exact | |
address. */ | |
lookup_t matchl = LOOKUP_VALUE (match); | |
info->dli_sname = strtab + matchsym->st_name; | |
info->dli_saddr = DL_SYMBOL_ADDRESS (matchl, matchsym); | |
} | |
else | |
{ | |
/* No symbol matches. We return only the containing object. */ | |
info->dli_sname = NULL; | |
info->dli_saddr = NULL; | |
} | |
result = 1; | |
} | |
__rtld_lock_unlock_recursive (GL(dl_load_lock)); | |
return result; | |
} | |
libc_hidden_def (_dl_addr) |