Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/elf/dl-addr.c
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
161 lines (136 sloc)
4.9 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* Locate the shared object symbol nearest a given address. | |
Copyright (C) 1996-2016 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, see | |
<http://www.gnu.org/licenses/>. */ | |
#include <dlfcn.h> | |
#include <stddef.h> | |
#include <ldsodefs.h> | |
static inline void | |
__attribute ((always_inline)) | |
determine_info (const ElfW(Addr) addr, struct link_map *match, Dl_info *info, | |
struct link_map **mapp, const ElfW(Sym) **symbolp) | |
{ | |
/* 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) *matchsym = NULL; | |
if (match->l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + DT_THISPROCNUM | |
+ DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM] != NULL) | |
{ | |
/* We look at all symbol table entries referenced by the hash | |
table. */ | |
for (Elf_Symndx bucket = 0; bucket < match->l_nbuckets; ++bucket) | |
{ | |
Elf32_Word symndx = match->l_gnu_buckets[bucket]; | |
if (symndx != 0) | |
{ | |
const Elf32_Word *hasharr = &match->l_gnu_chain_zero[symndx]; | |
do | |
{ | |
/* The hash table never references local symbols so | |
we can omit that test here. */ | |
if ((symtab[symndx].st_shndx != SHN_UNDEF | |
|| symtab[symndx].st_value != 0) | |
&& ELFW(ST_TYPE) (symtab[symndx].st_info) != STT_TLS | |
&& DL_ADDR_SYM_MATCH (match, &symtab[symndx], | |
matchsym, addr) | |
&& symtab[symndx].st_name < strtabsize) | |
matchsym = (ElfW(Sym) *) &symtab[symndx]; | |
++symndx; | |
} | |
while ((*hasharr++ & 1u) == 0); | |
} | |
} | |
} | |
else | |
{ | |
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; | |
for (; (void *) symtab < (void *) symtabend; ++symtab) | |
if ((ELFW(ST_BIND) (symtab->st_info) == STB_GLOBAL | |
|| ELFW(ST_BIND) (symtab->st_info) == STB_WEAK) | |
&& ELFW(ST_TYPE) (symtab->st_info) != STT_TLS | |
&& (symtab->st_shndx != SHN_UNDEF | |
|| symtab->st_value != 0) | |
&& DL_ADDR_SYM_MATCH (match, symtab, matchsym, addr) | |
&& symtab->st_name < strtabsize) | |
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; | |
} | |
} | |
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); | |
int result = 0; | |
/* Protect against concurrent loads and unloads. */ | |
__rtld_lock_lock_recursive (GL(dl_load_lock)); | |
struct link_map *l = _dl_find_dso_for_object (addr); | |
if (l) | |
{ | |
determine_info (addr, l, info, mapp, symbolp); | |
result = 1; | |
} | |
__rtld_lock_unlock_recursive (GL(dl_load_lock)); | |
return result; | |
} | |
libc_hidden_def (_dl_addr) | |
/* Return non-zero if ADDR lies within one of L's segments. */ | |
int | |
internal_function | |
_dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr) | |
{ | |
int n = l->l_phnum; | |
const ElfW(Addr) reladdr = addr - l->l_addr; | |
while (--n >= 0) | |
if (l->l_phdr[n].p_type == PT_LOAD | |
&& reladdr - l->l_phdr[n].p_vaddr >= 0 | |
&& reladdr - l->l_phdr[n].p_vaddr < l->l_phdr[n].p_memsz) | |
return 1; | |
return 0; | |
} |