tests/tail-2/tail-n0f

   1 #!/bin/sh
   2 # Make sure that `tail -n0 -f' and `tail -c0 -f' sleep
   3 # rather than doing what amounted to a busy-wait.
   4
   5 # Copyright (C) 2003, 2006-2007 Free Software Foundation, Inc.
   6
   7 # This program is free software: you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation, either version 3 of the License, or
  10 # (at your option) any later version.
  11
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 # This bug was fixed for 5.0.91
  21 # It skips the test if your system lacks a /proc/$pid/status
  22 # file, or if its contents don't look right.
  23
  24 if test "$VERBOSE" = yes; then
  25   set -x
  26   tail --version
  27 fi
  28
  29 . $srcdir/../test-lib.sh
  30
  31 sleep 2 &
  32 pid=$!
  33 sleep .5
  34 grep '^State:[   ]*[S]' /proc/$pid/status > /dev/null 2>&1 || \
  35   {
  36     echo "$0:/proc/$pid/status: missing or 'different': skipping this test" 1>&2
  37     (exit 77); exit 77
  38   }
  39 kill $pid
  40
  41 touch empty || framework_failure
  42 echo anything > nonempty || framework_failure
  43
  44 fail=0
  45
  46 for file in empty nonempty; do
  47   for c_or_n in c n; do
  48     tail --sleep=4 -${c_or_n} 0 -f $file &
  49     pid=$!
  50     sleep .5
  51     set _ `sed -n '/^State:[     ]*\([^  ]\)/s//\1/p' /proc/$pid/status`
  52     shift # Remove the leading `_'.
  53     state=$1
  54     case $state in
  55       S*) ;;
  56       *) echo $0: process in unexpected state: $state 1>&2; fail=1 ;;
  57     esac
  58     kill $pid
  59   done
  60 done
  61
  62 (exit $fail); exit $fail