#!/usr/bin/perl
#
# Copyright (c)  2009-2016 Andreas Beckmann <anbe@debian.org>
#                2010-2016 Russ Allbery <rra@debian.org>
#
# 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 2 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 script.  If not, see <http://www.gnu.org/licenses/>.
#
# This program comes from:
# https://anonscm.debian.org/viewvc/pkg-nvidia/packages/nvidia-graphics-drivers/trunk/debian/module/debian/kernel-version?view=markup
# The original copyright and license (GPL2+) can be found at:
# https://anonscm.debian.org/viewvc/pkg-nvidia/packages/nvidia-graphics-drivers/trunk/debian/copyright?view=markup
#
# Extract the kernel version from the kernel version header file.  Takes the
# kernel source path as its only argument.  If the version header couldn't be
# found, print nothing and exit quietly.

use warnings;

my $ksrc = shift;
unless ($ksrc && (-f "$ksrc/include/linux/version.h" || -f "$ksrc/include/generated/uapi/linux/version.h")) {
    exit 0;
}
my $found = 0;
my $line;
if (open (VERSION, "$ksrc/include/linux/version.h")) {
    if (defined(VERSION) && ($line = <VERSION>)) {
        if ($line =~ /"(.+)"/) {
            print "$1\n";
            $found = 1;
        }
    }
}
exit 0 if $found;
if (open (VERSION, "$ksrc/include/generated/utsrelease.h")) {
    if (defined(VERSION) && ($line = <VERSION>)) {
        if ($line =~ /UTS_RELEASE *"(.+)"/) {
            print "$1\n";
            $found = 1;
        }
    }
}
exit 0 if $found;
# kernel.release is no longer useful since 3.1.0
unless (open (VERSION, "$ksrc/include/config/kernel.release")) {
    exit 0;
}
if (defined(VERSION) && ($line = <VERSION>)) {
    print "$line";
}
exit 0;