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/* dladdr -- Locate the shared object symbol nearest a given address.
Copyright (C) 1996 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <stddef.h>
#include <link.h>
#include <dlfcn.h>
int
dladdr (void *address, Dl_info *info)
{
const Elf32_Addr addr = (Elf32_Addr) address;
struct link_map *l, *match;
const Elf32_Sym *symtab, *matchsym;
const char *strtab;
/* Find the highest-addressed object that ADDRESS is not below. */
match = NULL;
for (l = _dl_loaded; l; l = l->l_next)
if (addr >= l->l_addr && !match || match->l_addr < l->l_addr)
match = l;
if (match)
{
/* We know ADDRESS lies within MATCH if in any shared object.
Make sure it isn't past the end of MATCH's segments. */
size_t n = match->l_phnum;
do
--n;
while (match->l_phdr[n].p_type != PT_LOAD);
if (addr >= (match->l_addr +
match->l_phdr[n].p_vaddr + match->l_phdr[n].p_memsz))
/* Off the end of the highest-addressed shared object. */
return 0;
}
else
return 0;
/* Now we know what object the address lies in. */
info->dli_fname = match->l_name;
info->dli_fbase = (void *) match->l_addr;
symtab = ((void *) match->l_addr + match->l_info[DT_SYMTAB]->d_un.d_ptr);
strtab = ((void *) match->l_addr + match->l_info[DT_STRTAB]->d_un.d_ptr);
/* 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!! */
for (matchsym = NULL; (void *) symtab < (void *) strtab; ++symtab)
if (addr >= match->l_addr + symtab->st_value && !matchsym ||
matchsym->st_value < symtab->st_value &&
ELF32_ST_BIND (symtab->st_info) == STB_GLOBAL ||
ELF32_ST_BIND (symtab->st_info) == STB_WEAK)
matchsym = symtab;
if (matchsym)
{
/* We found a symbol close by. Fill in its name and exact address. */
info->dli_sname = strtab + matchsym->st_name;
info->dli_saddr = (void *) (match->l_addr + matchsym->st_value);
}
else
{
/* No symbol matches. We return only the containing object. */
info->dli_sname = NULL;
info->dli_saddr = NULL;
}
return 1;
}
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