1  /*
       2   * Check decoding of userfaultfd syscall.
       3   *
       4   * Copyright (c) 2015-2018 Dmitry V. Levin <ldv@strace.io>
       5   * Copyright (c) 2015-2021 The strace developers.
       6   * All rights reserved.
       7   *
       8   * SPDX-License-Identifier: GPL-2.0-or-later
       9   */
      10  
      11  #include "tests.h"
      12  #include "scno.h"
      13  
      14  #include <stdio.h>
      15  #include <unistd.h>
      16  #include "kernel_fcntl.h"
      17  
      18  #define UFFD_USER_MODE_ONLY 1
      19  
      20  static const char *errstr;
      21  
      22  static long
      23  k_userfaultfd(const unsigned int flags)
      24  {
      25  	const kernel_ulong_t fill = (kernel_ulong_t) 0xdefaced00000000ULL;
      26  	const kernel_ulong_t bad = (kernel_ulong_t) 0xbadc0dedbadc0dedULL;
      27  	const kernel_ulong_t arg1 = fill | flags;
      28  	const long rc = syscall(__NR_userfaultfd, arg1, bad, bad, bad, bad, bad);
      29  	errstr = sprintrc(rc);
      30  	return rc;
      31  }
      32  
      33  int
      34  main(void)
      35  {
      36  	struct {
      37  		unsigned int val;
      38  		const char *str;
      39  	} flags[] = {
      40  		{ ARG_STR(0) },
      41  		{ ARG_STR(O_NONBLOCK) },
      42  		{ ARG_STR(O_CLOEXEC) },
      43  		{ ARG_STR(O_NONBLOCK|O_CLOEXEC) },
      44  		{ ARG_STR(UFFD_USER_MODE_ONLY) },
      45  		{ ARG_STR(UFFD_USER_MODE_ONLY|O_NONBLOCK) },
      46  		{ ARG_STR(UFFD_USER_MODE_ONLY|O_CLOEXEC) },
      47  		{ ARG_STR(UFFD_USER_MODE_ONLY|O_NONBLOCK|O_CLOEXEC) },
      48  	};
      49  
      50  	for (unsigned int i = 0; i < ARRAY_SIZE(flags); ++i) {
      51  		k_userfaultfd(flags[i].val);
      52  		printf("userfaultfd(%s) = %s\n", flags[i].str, errstr);
      53  	}
      54  
      55  	k_userfaultfd(-1U);
      56  	printf("userfaultfd(UFFD_USER_MODE_ONLY|O_NONBLOCK|O_CLOEXEC|%#x)"
      57  	       " = %s\n", (-1U - UFFD_USER_MODE_ONLY - O_NONBLOCK - O_CLOEXEC),
      58  	       errstr);
      59  
      60  	puts("+++ exited with 0 +++");
      61  	return 0;
      62  }