imagehash.in 4.25 KB
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#!/usr/bin/perl -w
#
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# Copyright (c) 2010-2016 University of Utah and the Flux Group.
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# 
# {{{EMULAB-LICENSE
# 
# This file is part of the Emulab network testbed software.
# 
# This file is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or (at
# your option) any later version.
# 
# This file 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 Affero General Public
# License for more details.
# 
# You should have received a copy of the GNU Affero General Public License
# along with this file.  If not, see <http://www.gnu.org/licenses/>.
# 
# }}}
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#
use English;
use strict;
use Getopt::Std;
use Data::Dumper;

#
# Set/Get the hash for an image. 
#
sub usage()
{
    print("Usage: imagehash [-d] [-n] <imageid>\n" .
	  "       imagehash -p <imageid>\n" .
	  "Options:\n".
	  "       -d     Turn on debug mode\n".
	  "       -p     Show the current hash in the DB\n".
	  "       -n     Impotent mode; compute hash but do not update\n");
    
    exit(-1);
}
my $optlist   = "dnp";
my $debug     = 0;
my $showhash  = 0;
my $impotent  = 0;
my $hashfile;

#
# Configure variables
#
my $TB		= "@prefix@";
my $SHA1	= "/sbin/sha1";

# Protos
sub fatal($);
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sub ShowHash($);
sub UpdateHash($);
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#
# Untaint the path
#
$ENV{'PATH'} = "$TB/bin:$TB/sbin:/bin:/usr/bin:/usr/bin:/usr/sbin";
delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};

#
# Turn off line buffering on output
#
$| = 1;

#
# Load the Testbed support stuff.
#
use lib "@prefix@/lib";
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use OSImage;
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use User;

#
# Parse command arguments. Once we return from getopts, all that should be
# left are the required arguments.
#
my %options = ();
if (! getopts($optlist, \%options)) {
    usage();
}
if (defined($options{"d"})) {
    $debug = 1;
}
if (defined($options{"n"})) {
    $impotent = 1;
}
if (defined($options{"p"})) {
    $showhash = 1;
}
usage() 
    if (@ARGV != 1);

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my $image   = OSImage->Lookup($ARGV[0]);
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if (!defined($image)) {
    fatal("No such image exists");
}
my $imageid = $image->imageid();

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#
# Show the full hash if that's all we're doing.
#
if ($showhash) {
    ShowHash("full");
    exit(0);
}

#
# See if this is a Docker image; use libimageops if so.
#
if ($image->format() eq 'docker') {
    use libimageops;

    libimageops::setDebug(1)
	if ($debug);
    my %args = ('impotent' => $impotent,'showhash' => $showhash);

    my $iops = libimageops::Factory("image" => $image);
    my ($rc,$msg) = $iops->UpdateHash($image,\%args);
    if (!defined($rc) && defined($msg)) {
	print STDERR "Error: $msg\n";
	exit(1);
    }
    else {
	print "$rc\n";
	exit(0);
    }
}
else {
    UpdateHash("full");
    UpdateHash("delta");

    exit(0);
}

sub ShowHash($)
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{
    my ($which) = @_;
    my ($path, $hash);
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    if ($which eq "full") {
	$path      = $image->FullImageFile();
	$hash      = $image->hash();
	$hashfile  = $image->FullImageSHA1File()
    }
    else {
	$path      = $image->DeltaImageFile();
	$hash      = $image->deltahash();
	$hashfile  = $image->DeltaImageSHA1File()
    }
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    $hash = "No hash yet" if (!defined($hash));
    print "$path = $hash\n";
}

sub UpdateHash($)
{
    my ($which) = @_;
    my ($path, $hash);

    if ($which eq "full") {
	$path      = $image->FullImageFile();
	$hash      = $image->hash();
	$hashfile  = $image->FullImageSHA1File()
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    }
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    else {
	$path      = $image->DeltaImageFile();
	$hash      = $image->deltahash();
	$hashfile  = $image->DeltaImageSHA1File()
    }

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    return
	if (! -e $path);

    my $filehash = `$SHA1 $path`;
    if ($?) {
	fatal("Could not generate sha1 hash of $path");
    }
    if ($filehash =~ /^SHA1.*= (\w*)$/) {
	$hash = $1;
	if (!$impotent) {
	    $image->SetHash($1) == 0
		or fatal("Failed to set the hash for $image");
	}
    }
    else {
	fatal("Could not parse the sha1 hash: '$filehash'")
    }
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    if (!$impotent) {
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	unlink($hashfile)
	    if (-e $hashfile);
	open(HASH, ">$hashfile") or
	    fatal("Could not open $hashfile for writing: $!");
	print HASH $filehash;
	close($hashfile);
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    }
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    print "$path = $hash\n";
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}

sub fatal($)
{
    my ($mesg) = $_[0];

    die("*** $0:\n".
	"    $mesg\n");
}