usr/src/cmd/dtrace/test/tst/common/arithmetic/tst.nonarrow.ksh

   1 #
   2 # CDDL HEADER START
   3 #
   4 # The contents of this file are subject to the terms of the
   5 # Common Development and Distribution License (the "License").
   6 # You may not use this file except in compliance with the License.
   7 #
   8 # You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9 # or http://www.opensolaris.org/os/licensing.
  10 # See the License for the specific language governing permissions
  11 # and limitations under the License.
  12 #
  13 # When distributing Covered Code, include this CDDL HEADER in each
  14 # file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15 # If applicable, add the following below this CDDL HEADER, with the
  16 # fields enclosed by brackets "[]" replaced with your own identifying
  17 # information: Portions Copyright [yyyy] [name of copyright owner]
  18 #
  19 # CDDL HEADER END
  20 #
  21
  22 #
  23 # Copyright (c) 2012, Joyent, Inc. All rights reserved.
  24 #
  25
  26 #
  27 # Somewhat surprisingly, DTrace very much relies on the fact that when 32-bit
  28 # is forced, pointers are not, in fact, narrowed to 32-bits.  In particular, if
  29 # this is not so (that is, if pointers are narrowed to their seemingly correct
  30 # 32-bit width), helpers attached to 32-bit programs will fail to operate:
  31 # they will erroneously zero the high 32-bits of the return values of 64-bit
  32 # kernel pointers as returned by copyin(), alloca(), etc.  This test asserts
  33 # this implicit behavior -- and this comment regrettably serves as this
  34 # behavior's only documentation.
  35 #
  36 doit()
  37 {
  38         /usr/sbin/dtrace $1 -n BEGIN'{trace(sizeof (long))}' \
  39             -n 'BEGIN{*(int *)alloca(4) = 21506; exit(0)}' \
  40             -n 'ERROR{exit(1)}'
  41
  42         if [ "$?" -ne 0 ]; then
  43                 exit $?
  44         fi
  45 }
  46
  47 doit
  48 doit -32