build-aux/relocatable.sh.in

   1 # The functions in this file provide support for relocatability of
   2 # shell scripts.  They should be included near the beginning of each
   3 # shell script in a relocatable program, by adding @relocatable_sh@
   4 # and causing the script to be expanded with AC_CONFIG_FILES.  A
   5 # small amount of additional code must be added and adapted to the
   6 # package by hand; see doc/relocatable-maint.texi (in Gnulib) for
   7 # details.
   8 #
   9 # Copyright (C) 2003-2024 Free Software Foundation, Inc.
  10 #
  11 # This file is free software: you can redistribute it and/or modify
  12 # it under the terms of the GNU General Public License as published
  13 # by the Free Software Foundation; either version 2 of the License,
  14 # or (at your option) any later version.
  15 #
  16 # This file is distributed in the hope that it will be useful,
  17 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 # GNU General Public License for more details.
  20 #
  21 # You should have received a copy of the GNU General Public License
  22 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  23 #
  24
  25 # Support for relocatability.
  26 func_find_curr_installdir ()
  27 {
  28   # Determine curr_installdir, even taking into account symlinks.
  29   curr_executable="$0"
  30   case "$curr_executable" in
  31     */* | *\\*) ;;
  32     *) # Need to look in the PATH.
  33       if test "${PATH_SEPARATOR+set}" != set; then
  34         # Determine PATH_SEPARATOR by trying to find /bin/sh in a PATH which
  35         # contains only /bin. Note that ksh looks also at the FPATH variable,
  36         # so we have to set that as well for the test.
  37         PATH_SEPARATOR=:
  38         (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
  39           && { (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
  40                  || PATH_SEPARATOR=';'
  41              }
  42       fi
  43       saved_IFS="$IFS"; IFS="$PATH_SEPARATOR"
  44       for dir in $PATH; do
  45         IFS="$saved_IFS"
  46         test -z "$dir" && dir=.
  47         for exec_ext in ''; do
  48           if test -f "$dir/$curr_executable$exec_ext"; then
  49             curr_executable="$dir/$curr_executable$exec_ext"
  50             break 2
  51           fi
  52         done
  53       done
  54       IFS="$saved_IFS"
  55       ;;
  56   esac
  57   # Make absolute.
  58   case "$curr_executable" in
  59     /* | ?:/* | ?:\\*) ;;
  60     *) curr_executable=`pwd`/"$curr_executable" ;;
  61   esac
  62   # Resolve symlinks.
  63   sed_dirname='s,/[^/]*$,,'
  64   sed_linkdest='s,^.* -> \(.*\),\1,p'
  65   while : ; do
  66     lsline=`LC_ALL=C ls -l "$curr_executable"`
  67     case "$lsline" in
  68       *" -> "*)
  69         linkdest=`echo "$lsline" | sed -n -e "$sed_linkdest"`
  70         case "$linkdest" in
  71           /* | ?:/* | ?:\\*) curr_executable="$linkdest" ;;
  72           *) curr_executable=`echo "$curr_executable" | sed -e "$sed_dirname"`/"$linkdest" ;;
  73         esac ;;
  74       *) break ;;
  75     esac
  76   done
  77   curr_installdir=`echo "$curr_executable" | sed -e 's,/[^/]*$,,'`
  78   # Canonicalize.
  79   curr_installdir=`cd "$curr_installdir" && pwd`
  80 }
  81 func_find_prefixes ()
  82 {
  83   # Compute the original/current installation prefixes by stripping the
  84   # trailing directories off the original/current installation directories.
  85   orig_installprefix="$orig_installdir"
  86   curr_installprefix="$curr_installdir"
  87   while true; do
  88     orig_last=`echo "$orig_installprefix" | sed -n -e 's,^.*/\([^/]*\)$,\1,p'`
  89     curr_last=`echo "$curr_installprefix" | sed -n -e 's,^.*/\([^/]*\)$,\1,p'`
  90     if test -z "$orig_last" || test -z "$curr_last"; then
  91       break
  92     fi
  93     if test "$orig_last" != "$curr_last"; then
  94       break
  95     fi
  96     orig_installprefix=`echo "$orig_installprefix" | sed -e 's,/[^/]*$,,'`
  97     curr_installprefix=`echo "$curr_installprefix" | sed -e 's,/[^/]*$,,'`
  98   done
  99 }