check-copyright

#!/bin/sh
#
# Copyright (C) 2011-2024 Free Software Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#

# func_file_license
# Input:
# - file          A file name.
# Output:
# - file_license  The license mentioned in the file,
#                 or a token with '??' if unknown.
func_file_license ()
{
  if head -n 50 $file | grep 'the GNU LGPLv3[+] or the GNU GPLv2[+]' > /dev/null \
     || { { head -n 50 $file | grep 'under the terms of either:' > /dev/null; } \
          && { head -n 50 $file | grep 'GNU Lesser General Public' > /dev/null; } \
          && { head -n 50 $file | grep 'GNU General Public' > /dev/null; } \
          && { head -n 50 $file | grep 'either version 3' > /dev/null; } \
          && { head -n 50 $file | grep 'either version 2' > /dev/null; }; }; then
    file_license='LGPLv3+ or GPLv2+'
  else
    if head -n 50 $file | grep 'GNU General Public' > /dev/null; then
      if { head -n 50 $file | grep 'version 3 or later' > /dev/null; } \
         || { head -n 50 $file | grep 'either version 3' > /dev/null; }; then
        file_license='GPL' # an alias for GPLv3+
      else
        if { head -n 50 $file | grep 'version 2 or later' > /dev/null; } \
           || { head -n 50 $file | grep 'either version 2' > /dev/null; }; then
          file_license='GPLv2+'
        else
          file_license='GPL??'
        fi
      fi
    else
      if head -n 50 $file | grep 'Lesser General' > /dev/null; then
        if { head -n 50 $file | grep 'version 3 or later' > /dev/null; } \
           || { head -n 50 $file | grep 'either version 3' > /dev/null; }; then
          file_license='LGPL' # an alias for LGPLv3+
        else
          if { head -n 50 $file | grep 'version 2 or later' > /dev/null; } \
             || { head -n 50 $file | tr -d '\n' | grep 'version 2 of the *. *License, or' > /dev/null; } \
             || { head -n 50 $file | tr -d '\n' | grep 'version 2\.1 of the *. *License, or' > /dev/null; }; then
            file_license='LGPLv2+'
          else
            file_license='LGPL??'
          fi
        fi
      else
        if head -n 50 $file | grep 'unlimited permission to copy and/or distribute' > /dev/null; then
          file_license='unlimited'
        else
          if head -n 50 $file | grep 'This file is in the public domain' > /dev/null; then
            file_license='public domain'
          else
            file_license='??'
          fi
        fi
      fi
    fi
  fi
}

# func_module_license
# Input:
# - module          A module name.
# Output:
# - module_license  The license mentioned in the module.
func_module_license ()
{
  module_license=`./gnulib-tool --extract-license $module`
  if test "$module_license" = 'GPLv3+' || test "$module_license" = 'GPLed build tool'; then
    module_license='GPL'
  else
    if test "$module_license" = 'GPLv2+ build tool'; then
      module_license='GPLv2+'
    fi
  fi
}

# func_weaker_license license1 license2
# Determines the weaker among the licenses license1, license2.
# Input:
# - license1        A license.
# - license2        A license.
# Output:
# - weaker_license  The weaker among the licenses license1, license2.
func_weaker_license ()
{
  if test "$1" = 'public domain' || test "$2" = 'public domain'; then
    weaker_license='public domain'
  else
    if test "$1" = 'unlimited' || test "$2" = 'unlimited'; then
      weaker_license='unlimited'
    else
      if test "$1" = 'LGPLv2+' || test "$2" = 'LGPLv2+'; then
        weaker_license='LGPLv2+'
      else
        if test "$1" = 'LGPLv3+ or GPLv2+' || test "$2" = 'LGPLv3+ or GPLv2+'; then
          weaker_license='LGPLv3+ or GPLv2+'
        else
          if { test "$1" = 'LGPL' && test "$2" != 'GPLv2+'; } \
             || { test "$2" = 'LGPL' && test "$1" != 'GPLv2+'; }; then
            weaker_license='LGPL'
          else
            if { test "$1" = 'GPLv2+' && test "$2" != 'LGPL'; } \
               || { test "$2" = 'GPLv2+' && test "$1" != 'LGPL'; }; then
              weaker_license='GPLv2+'
            else
              if test "$1" = "$2"; then
                weaker_license="$1"
              else
                weaker_license='<complex>'
              fi
            fi
          fi
        fi
      fi
    fi
  fi
}

# Iterate over the modules and collect the mismatch candidates.
candidates=
for module in `./gnulib-tool --list`; do
  func_module_license
  for file in `./gnulib-tool --extract-filelist "$module" | grep '^\(lib\|build-aux\)/'`; do
    case $file in
      *.class) # These are binary files, that don't contain a license notice.
        ;;
      *)
        func_file_license
        if test "$file_license" != "$module_license"; then
          # This pair (module, file) is a mismatch candidate.
          case " $candidates " in
            *" $file "*) ;;
            *)
               candidates="$candidates $file" ;;
          esac
        fi
        ;;
    esac
  done
done

# Look at the candidates in more detail.
error=0
for file in $candidates; do
  func_file_license
  weakest_license=
  for module in `./gnulib-tool --find "$file"`; do
    func_module_license
    if test -z "$weakest_license"; then
      weakest_license="$module_license"
    else
      func_weaker_license "$weakest_license" "$module_license"
      weakest_license="$weaker_license"
    fi
  done
  if test "$file_license" != "$weakest_license"; then
    # The 'glob' module is a special case. It contains LGPLv2+ code (shared with
    # glibc) but at the same time also has a dependency to a module under GPL
    # (namely, 'fstatat'). This is not a mistake.
    if test "$weakest_license" = GPL \
       && case "$file" in lib/glob*) true ;; *) false ;; esac; then
      :
    else
      if test $error = 0; then
        echo "Module License    File License      File name"
        echo "================= ================= ====================================="
      fi
      printf '%-17s %-17s %s\n' "$weakest_license" "$file_license" "$file"
      error=1
    fi
  fi
done
exit $error