1 /* Operating system specific code for generic dynamic loader functions. Linux.
2 Copyright (C) 2000-2017 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 <http://www.gnu.org/licenses/>. */
19 #include <dl-sysdep.h>
23 #include <not-cancel.h>
26 # define MIN(a,b) (((a)<(b))?(a):(b))
29 #define DL_SYSDEP_OSCHECK(FATAL) \
31 /* Test whether the kernel is new enough. This test is only performed \
32 if the library is not compiled to run on all kernels. */ \
34 int version = _dl_discover_osversion (); \
35 if (__glibc_likely (version >= 0)) \
37 if (__builtin_expect (GLRO(dl_osversion) == 0, 1) \
38 || GLRO(dl_osversion) > version) \
39 GLRO(dl_osversion) = version; \
41 /* Now we can test with the required version. */ \
42 if (__LINUX_KERNEL_VERSION > 0 && version < __LINUX_KERNEL_VERSION) \
43 /* Not sufficent. */ \
44 FATAL ("FATAL: kernel too old\n"); \
46 else if (__LINUX_KERNEL_VERSION > 0) \
47 FATAL ("FATAL: cannot determine kernel version\n"); \
50 static inline uintptr_t __attribute__ ((always_inline
))
51 _dl_setup_stack_chk_guard (void *dl_random
)
56 unsigned char bytes
[sizeof (uintptr_t)];
59 /* We need in the moment only 8 bytes on 32-bit platforms and 16
60 bytes on 64-bit platforms. Therefore we can use the data
61 directly and not use the kernel-provided data to seed a PRNG. */
62 memcpy (ret
.bytes
, dl_random
, sizeof (ret
));
63 #if BYTE_ORDER == LITTLE_ENDIAN
64 ret
.num
&= ~(uintptr_t) 0xff;
65 #elif BYTE_ORDER == BIG_ENDIAN
66 ret
.num
&= ~((uintptr_t) 0xff << (8 * (sizeof (ret
) - 1)));
68 # error "BYTE_ORDER unknown"
73 static inline uintptr_t __attribute__ ((always_inline
))
74 _dl_setup_pointer_guard (void *dl_random
, uintptr_t stack_chk_guard
)
77 memcpy (&ret
, (char *) dl_random
+ sizeof (ret
), sizeof (ret
));