uclibc-ng/libc/sysdeps/linux/common/dl-osinfo.h

/*
 * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org>
 *
 * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
 */

#ifndef _DL_OSINFO_H
#define _DL_OSINFO_H 1

#include <features.h>

#ifdef __UCLIBC_HAS_SSP__
# if defined IS_IN_libc || defined IS_IN_rtld

#  if defined __SSP__ || defined __SSP_ALL__
#   error "file must not be compiled with stack protection enabled on it. Use -fno-stack-protector"
#  endif

#  include <stdint.h>
#  include <sys/time.h>

#  ifdef IS_IN_libc
#   ifndef __SSP_QUICK_CANARY__
#     define OPEN __open
#     define READ __read
#     define CLOSE __close
#   endif
#   define GETTIMEOFDAY gettimeofday
#  else
#   ifndef __SSP_QUICK_CANARY__
#    define OPEN _dl_open
#    define READ _dl_read
#    define CLOSE _dl_close
#   endif
#   define GETTIMEOFDAY _dl_gettimeofday
#  endif

static __always_inline uintptr_t _dl_setup_stack_chk_guard(void)
{
	uintptr_t ret;
#  ifndef __SSP_QUICK_CANARY__
	{
		int fd = OPEN("/dev/urandom", O_RDONLY, 0);
		if (fd >= 0) {
			size_t size = READ(fd, &ret, sizeof(ret));
			CLOSE(fd);
			if (size == (size_t) sizeof(ret))
				return ret;
		}
	}
#  endif /* !__SSP_QUICK_CANARY__ */

	/* Start with the "terminator canary". */
	ret = 0xFF0A0D00UL;

	/* Everything failed? Or we are using a weakened model of the 
	 * terminator canary */
	{
		struct timeval tv;
		if (GETTIMEOFDAY(&tv, NULL) != (-1))
			ret ^= tv.tv_usec ^ tv.tv_sec;
	}
	return ret;
}
# endif /* libc || rtld */
#endif /* __UCLIBC_HAS_SSP__ */

#endif /* _DL_OSINFO_H */