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87 lines
2.8 KiB
C
87 lines
2.8 KiB
C
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/* dladdr -- Locate the shared object symbol nearest a given address.
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Copyright (C) 1996 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
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <stddef.h>
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#include <link.h>
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#include <dlfcn.h>
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int
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dladdr (void *address, Dl_info *info)
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{
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const Elf32_Addr addr = (Elf32_Addr) address;
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struct link_map *l, *match;
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const Elf32_Sym *symtab, *matchsym;
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const char *strtab;
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/* Find the highest-addressed object that ADDRESS is not below. */
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match = NULL;
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for (l = _dl_loaded; l; l = l->l_next)
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if (addr >= l->l_addr && !match || match->l_addr < l->l_addr)
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match = l;
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if (match)
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{
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/* We know ADDRESS lies within MATCH if in any shared object.
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Make sure it isn't past the end of MATCH's segments. */
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size_t n = match->l_phnum;
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do
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--n;
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while (match->l_phdr[n].p_type != PT_LOAD);
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if (addr >= (match->l_addr +
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match->l_phdr[n].p_vaddr + match->l_phdr[n].p_memsz))
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/* Off the end of the highest-addressed shared object. */
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return 0;
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}
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else
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return 0;
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/* Now we know what object the address lies in. */
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info->dli_fname = match->l_name;
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info->dli_fbase = (void *) match->l_addr;
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symtab = ((void *) match->l_addr + match->l_info[DT_SYMTAB]->d_un.d_ptr);
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strtab = ((void *) match->l_addr + match->l_info[DT_STRTAB]->d_un.d_ptr);
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/* We assume that the string table follows the symbol table, because
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there is no way in ELF to know the size of the dynamic symbol table!! */
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for (matchsym = NULL; (void *) symtab < (void *) strtab; ++symtab)
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if (addr >= match->l_addr + symtab->st_value && !matchsym ||
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matchsym->st_value < symtab->st_value &&
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ELF32_ST_BIND (symtab->st_info) == STB_GLOBAL ||
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ELF32_ST_BIND (symtab->st_info) == STB_WEAK)
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matchsym = symtab;
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if (matchsym)
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{
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/* We found a symbol close by. Fill in its name and exact address. */
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info->dli_sname = strtab + matchsym->st_name;
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info->dli_saddr = (void *) (match->l_addr + matchsym->st_value);
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}
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else
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{
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/* No symbol matches. We return only the containing object. */
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info->dli_sname = NULL;
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info->dli_saddr = NULL;
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}
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return 1;
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}
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