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glibc/sysdeps/unix/sysv/linux/dl-osinfo.h
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/* Operating system specific code for generic dynamic loader functions. Linux. | |
Copyright (C) 2000-2016 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 <dl-sysdep.h> | |
#include <endian.h> | |
#include <fcntl.h> | |
#include <stdint.h> | |
#include <not-cancel.h> | |
#ifndef MIN | |
# define MIN(a,b) (((a)<(b))?(a):(b)) | |
#endif | |
#define DL_SYSDEP_OSCHECK(FATAL) \ | |
do { \ | |
/* Test whether the kernel is new enough. This test is only performed \ | |
if the library is not compiled to run on all kernels. */ \ | |
\ | |
int version = _dl_discover_osversion (); \ | |
if (__glibc_likely (version >= 0)) \ | |
{ \ | |
if (__builtin_expect (GLRO(dl_osversion) == 0, 1) \ | |
|| GLRO(dl_osversion) > version) \ | |
GLRO(dl_osversion) = version; \ | |
\ | |
/* Now we can test with the required version. */ \ | |
if (__LINUX_KERNEL_VERSION > 0 && version < __LINUX_KERNEL_VERSION) \ | |
/* Not sufficent. */ \ | |
FATAL ("FATAL: kernel too old\n"); \ | |
} \ | |
else if (__LINUX_KERNEL_VERSION > 0) \ | |
FATAL ("FATAL: cannot determine kernel version\n"); \ | |
} while (0) | |
static inline uintptr_t __attribute__ ((always_inline)) | |
_dl_setup_stack_chk_guard (void *dl_random) | |
{ | |
union | |
{ | |
uintptr_t num; | |
unsigned char bytes[sizeof (uintptr_t)]; | |
} ret; | |
/* We need in the moment only 8 bytes on 32-bit platforms and 16 | |
bytes on 64-bit platforms. Therefore we can use the data | |
directly and not use the kernel-provided data to seed a PRNG. */ | |
memcpy (ret.bytes, dl_random, sizeof (ret)); | |
#if BYTE_ORDER == LITTLE_ENDIAN | |
ret.num &= ~(uintptr_t) 0xff; | |
#elif BYTE_ORDER == BIG_ENDIAN | |
ret.num &= ~((uintptr_t) 0xff << (8 * (sizeof (ret) - 1))); | |
#else | |
# error "BYTE_ORDER unknown" | |
#endif | |
return ret.num; | |
} | |
static inline uintptr_t __attribute__ ((always_inline)) | |
_dl_setup_pointer_guard (void *dl_random, uintptr_t stack_chk_guard) | |
{ | |
uintptr_t ret; | |
memcpy (&ret, (char *) dl_random + sizeof (ret), sizeof (ret)); | |
return ret; | |
} |