1 /* Operating system specific code for generic dynamic loader functions. Linux.
2 Copyright (C) 2000-2024 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, see
17 <https://www.gnu.org/licenses/>. */
19 #include <dl-sysdep.h>
23 #include <not-cancel.h>
25 static inline uintptr_t __attribute__ ((always_inline
))
26 _dl_setup_stack_chk_guard (void *dl_random
)
31 unsigned char bytes
[sizeof (uintptr_t)];
34 /* We need in the moment only 8 bytes on 32-bit platforms and 16
35 bytes on 64-bit platforms. Therefore we can use the data
36 directly and not use the kernel-provided data to seed a PRNG. */
37 memcpy (ret
.bytes
, dl_random
, sizeof (ret
));
38 #if BYTE_ORDER == LITTLE_ENDIAN
39 ret
.num
&= ~(uintptr_t) 0xff;
40 #elif BYTE_ORDER == BIG_ENDIAN
41 ret
.num
&= ~((uintptr_t) 0xff << (8 * (sizeof (ret
) - 1)));
43 # error "BYTE_ORDER unknown"
48 static inline uintptr_t __attribute__ ((always_inline
))
49 _dl_setup_pointer_guard (void *dl_random
, uintptr_t stack_chk_guard
)
52 memcpy (&ret
, (char *) dl_random
+ sizeof (ret
), sizeof (ret
));