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Diffstat (limited to 'REORG.TODO/elf/dl-addr.c')
| -rw-r--r-- | REORG.TODO/elf/dl-addr.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/REORG.TODO/elf/dl-addr.c b/REORG.TODO/elf/dl-addr.c new file mode 100644 index 0000000000..1fac63d1a9 --- /dev/null +++ b/REORG.TODO/elf/dl-addr.c @@ -0,0 +1,146 @@ +/* Locate the shared object symbol nearest a given address. + Copyright (C) 1996-2017 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) + && __glibc_likely (!dl_symbol_visibility_binds_local_p (symtab)) + && 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) |