1 /*
2 * Copyright (C) 2013 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <stddef.h>
30 #include <sys/cdefs.h>
31 #include <sys/auxv.h>
32 #include <private/bionic_auxv.h>
33 #include <private/bionic_globals.h>
34 #include <private/bionic_ifuncs.h>
35 #include <elf.h>
36 #include <errno.h>
37
38 // This function needs to be safe to call before TLS is set up, so it can't
39 // access errno or the stack protector.
__bionic_getauxval(unsigned long type,bool * exists)40 __LIBC_HIDDEN__ unsigned long __bionic_getauxval(unsigned long type, bool* exists) {
41 for (ElfW(auxv_t)* v = __libc_shared_globals()->auxv; v->a_type != AT_NULL; ++v) {
42 if (v->a_type == type) {
43 *exists = true;
44 return v->a_un.a_val;
45 }
46 }
47 *exists = false;
48 return 0;
49 }
50
getauxval(unsigned long type)51 extern "C" unsigned long getauxval(unsigned long type) {
52 bool exists;
53 unsigned long result = __bionic_getauxval(type, &exists);
54 if (!exists) errno = ENOENT;
55 return result;
56 }
57