tests/misc/readlink-fp-loop.sh

   1 #!/bin/sh
   2 # readlink from 6.9 would fail with a false-positive symlink loop error
   3
   4 # Copyright (C) 2007-2019 Free Software Foundation, Inc.
   5
   6 # This program is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  18
  19 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
  20 print_ver_ readlink pwd
  21 cwd=$(env pwd -P)
  22
  23 # To trigger this bug, we have to construct a name/situation during
  24 # the resolution of which the code dereferences the same symlink (S)
  25 # two different times with no actual loop.  In addition, arrange
  26 # so that the second and fourth calls to readlink operate on S.
  27
  28 ln -s s p        || framework_failure_
  29 ln -s d s        || framework_failure_
  30 mkdir d          || framework_failure_
  31 echo 2 > d/2     || framework_failure_
  32 ln -s ../s/2 d/1 || framework_failure_
  33
  34 # With coreutils-6.9, this would fail with ELOOP.
  35 readlink -v -e p/1 > out || fail=1
  36 # readlink -e d/2 > exp || fail=1
  37 echo "$cwd/d/2" > exp || framework_failure_
  38 compare exp out || fail=1
  39
  40 # Construct a real loop and make sure readlink still detects it.
  41 ln -sf ../s/1 d/2 || framework_failure_
  42 readlink -v -e p/1 2> out && fail=1
  43 readlink_msg=$(cat out)
  44 case $readlink_msg in
  45   "readlink: p/1: "*) ;;
  46   *) fail=1;;
  47 esac
  48 symlink_loop_msg=${readlink_msg#"readlink: p/1: "}
  49
  50 # Exercise the hash table code.
  51 ln -nsf ../s/3 d/2 || framework_failure_
  52 ln -nsf ../p/4 d/3 || framework_failure_
  53 ln -nsf ../p/5 d/4 || framework_failure_
  54 ln -nsf ../p/6 d/5 || framework_failure_
  55 ln -nsf ../p/7 d/6 || framework_failure_
  56 ln -nsf ../p/8 d/7 || framework_failure_
  57 echo x > d/8       || framework_failure_
  58 readlink -v -e p/1 > out || fail=1
  59 echo "$cwd/d/8" > exp || framework_failure_
  60 compare exp out || fail=1
  61
  62 # A trivial loop
  63 ln -s loop loop
  64 readlink -v -e loop 2> out && fail=1
  65 echo "readlink: loop: $symlink_loop_msg" > exp || framework_failure_
  66 compare exp out || fail=1
  67
  68 Exit $fail