Update.
[glibc.git] / elf / dl-addr.c
blobae97398bad7617ee4498863d1220f20297b1010f
1 /* Locate the shared object symbol nearest a given address.
2 Copyright (C) 1996-2003, 2004 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #include <dlfcn.h>
21 #include <stddef.h>
22 #include <ldsodefs.h>
25 int
26 internal_function
27 _dl_addr (const void *address, Dl_info *info,
28 struct link_map **mapp, const ElfW(Sym) **symbolp)
30 const ElfW(Addr) addr = DL_LOOKUP_ADDRESS (address);
31 struct link_map *l, *match;
32 const ElfW(Sym) *symtab, *matchsym, *symtabend;
33 const char *strtab;
34 ElfW(Word) strtabsize;
36 /* Protect against concurrent loads and unloads. */
37 __rtld_lock_lock_recursive (GL(dl_load_lock));
39 /* Find the highest-addressed object that ADDRESS is not below. */
40 match = NULL;
41 for (l = GL(dl_loaded); l; l = l->l_next)
42 if (addr >= l->l_map_start && addr < l->l_map_end)
44 /* We know ADDRESS lies within L if in any shared object.
45 Make sure it isn't past the end of L's segments. */
46 size_t n = l->l_phnum;
47 if (n > 0)
50 --n;
51 while (l->l_phdr[n].p_type != PT_LOAD);
52 if (addr >= (l->l_addr +
53 l->l_phdr[n].p_vaddr + l->l_phdr[n].p_memsz))
54 /* Off the end of the highest-addressed shared object. */
55 continue;
58 match = l;
59 break;
62 int result = 0;
63 if (match != NULL)
65 /* Now we know what object the address lies in. */
66 info->dli_fname = match->l_name;
67 info->dli_fbase = (void *) match->l_map_start;
69 /* If this is the main program the information is incomplete. */
70 if (__builtin_expect (l->l_name[0], 'a') == '\0'
71 && l->l_type == lt_executable)
72 info->dli_fname = _dl_argv[0];
74 symtab = (const void *) D_PTR (match, l_info[DT_SYMTAB]);
75 strtab = (const void *) D_PTR (match, l_info[DT_STRTAB]);
77 strtabsize = match->l_info[DT_STRSZ]->d_un.d_val;
79 if (match->l_info[DT_HASH] != NULL)
80 symtabend = (symtab
81 + ((Elf_Symndx *) D_PTR (match, l_info[DT_HASH]))[1]);
82 else
83 /* There is no direct way to determine the number of symbols in the
84 dynamic symbol table and no hash table is present. The ELF
85 binary is ill-formed but what shall we do? Use the beginning of
86 the string table which generally follows the symbol table. */
87 symtabend = (const ElfW(Sym) *) strtab;
89 /* We assume that the string table follows the symbol table,
90 because there is no way in ELF to know the size of the
91 dynamic symbol table!! */
92 for (matchsym = NULL; (void *) symtab < (void *) symtabend; ++symtab)
93 if (addr >= match->l_addr + symtab->st_value
94 && ((symtab->st_size == 0
95 && addr == match->l_addr + symtab->st_value)
96 || addr < match->l_addr + symtab->st_value + symtab->st_size)
97 && symtab->st_name < strtabsize
98 && (matchsym == NULL || matchsym->st_value < symtab->st_value)
99 && (ELFW(ST_BIND) (symtab->st_info) == STB_GLOBAL
100 || ELFW(ST_BIND) (symtab->st_info) == STB_WEAK))
101 matchsym = (ElfW(Sym) *) symtab;
103 if (mapp)
104 *mapp = match;
105 if (symbolp)
106 *symbolp = matchsym;
108 if (matchsym)
110 /* We found a symbol close by. Fill in its name and exact
111 address. */
112 info->dli_sname = strtab + matchsym->st_name;
113 info->dli_saddr = (void *) (match->l_addr + matchsym->st_value);
115 else
117 /* No symbol matches. We return only the containing object. */
118 info->dli_sname = NULL;
119 info->dli_saddr = NULL;
122 result = 1;
125 __rtld_lock_unlock_recursive (GL(dl_load_lock));
127 return result;
129 libc_hidden_def (_dl_addr)