Mass Deface
Email Grabber
is often the quickest way to compute SHA message
digests. The user simply feeds data to the script through files or
standard input, and then collects the results from standard output.
The following command shows how to compute digests for typical inputs
such as the NIST test vector "abc":
perl -e "print qq(abc)" | shasum
Or, if you want to use SHA-256 instead of the default SHA-1, simply say:
perl -e "print qq(abc)" | shasum -a 256
Since I mimics the behavior of the combined GNU I,
I, I, I, and I programs,
you can install this script as a convenient drop-in replacement.
Unlike the GNU programs, I encompasses the full SHA standard by
allowing partial-byte inputs. This is accomplished through the BITS
option (I<-0>). The following example computes the SHA-224 digest of
the 7-bit message I<0001100>:
perl -e "print qq(0001100)" | shasum -0 -a 224
=head1 AUTHOR
Copyright (c) 2003-2013 Mark Shelor .
=head1 SEE ALSO
I is implemented using the Perl module L or
L.
=cut
END_OF_POD
use strict;
use Fcntl;
use Getopt::Long;
my $VERSION = "5.85";
## Try to use Digest::SHA. If not installed, use the slower
## but functionally equivalent Digest::SHA::PurePerl instead.
my $MOD_PREFER = "Digest::SHA";
my $MOD_SECOND = "Digest::SHA::PurePerl";
my $module = $MOD_PREFER;
eval "require $module";
if ($@) {
$module = $MOD_SECOND;
eval "require $module";
die "Unable to find $MOD_PREFER or $MOD_SECOND\n" if $@;
}
sub usage {
my($err, $msg) = @_;
$msg = "" unless defined $msg;
if ($err) {
warn($msg . "Type shasum -h for help\n");
exit($err);
}
my($USAGE) = $POD =~ /SYNOPSIS\n\n(.+)\n=head1 DESCRIPTION\n/sm;
$USAGE =~ s/^ //gm;
print $USAGE;
exit($err);
}
## Sync stdout and stderr by forcing a flush after every write
select((select(STDOUT), $| = 1)[0]);
select((select(STDERR), $| = 1)[0]);
## Collect options from command line
my ($alg, $binary, $check, $text, $status, $warn, $help, $version);
my ($portable, $BITS);
eval { Getopt::Long::Configure ("bundling") };
GetOptions(
'b|binary' => \$binary, 'c|check' => \$check,
't|text' => \$text, 'a|algorithm=i' => \$alg,
's|status' => \$status, 'w|warn' => \$warn,
'h|help' => \$help, 'v|version' => \$version,
'p|portable' => \$portable,
'0|01' => \$BITS
) or usage(1, "");
## Deal with help requests and incorrect uses
usage(0)
if $help;
usage(1, "shasum: Ambiguous file mode\n")
if scalar(grep {defined $_} ($binary, $portable, $text, $BITS)) > 1;
usage(1, "shasum: --warn option used only when verifying checksums\n")
if $warn && !$check;
usage(1, "shasum: --status option used only when verifying checksums\n")
if $status && !$check;
## Default to SHA-1 unless overridden by command line option
$alg = 1 unless defined $alg;
grep { $_ == $alg } (1, 224, 256, 384, 512, 512224, 512256)
or usage(1, "shasum: Unrecognized algorithm\n");
## Display version information if requested
if ($version) {
print "$VERSION\n";
exit(0);
}
## Try to figure out if the OS is DOS-like. If it is,
## default to binary mode when reading files, unless
## explicitly overridden by command line "--text" or
## "--portable" options.
my $isDOSish = ($^O =~ /^(MSWin\d\d|os2|dos|mint|cygwin)$/);
if ($isDOSish) { $binary = 1 unless $text || $portable }
my $modesym = $binary ? '*' : ($portable ? '?' : ($BITS ? '^' : ' '));
## Read from STDIN (-) if no files listed on command line
@ARGV = ("-") unless @ARGV;
## sumfile($file): computes SHA digest of $file
sub sumfile {
my $file = shift;
my $mode = $portable ? 'p' : ($binary ? 'b' : ($BITS ? '0' : ''));
my $digest = eval { $module->new($alg)->addfile($file, $mode) };
if ($@) { warn "shasum: $file: $!\n"; return }
$digest->hexdigest;
}
## %len2alg: maps hex digest length to SHA algorithm
my %len2alg = (40 => 1, 56 => 224, 64 => 256, 96 => 384, 128 => 512);
$len2alg{56} = 512224 if $alg == 512224;
$len2alg{64} = 512256 if $alg == 512256;
## unescape: convert backslashed filename to plain filename
sub unescape {
$_ = shift;
s/\\\\/\0/g;
s/\\n/\n/g;
return if /\\/;
s/\0/\\/g;
return $_;
}
## verify: confirm the digest values in a checksum file
sub verify {
my $checkfile = shift;
my ($err, $fmt_errs, $read_errs, $match_errs) = (0, 0, 0, 0);
my ($num_lines, $num_files) = (0, 0);
my ($bslash, $sum, $fname, $rsp, $digest);
local *FH;
$checkfile eq '-' and open(FH, '< -')
and $checkfile = 'standard input'
or sysopen(FH, $checkfile, O_RDONLY)
or die "shasum: $checkfile: $!\n";
while () {
next if /^#/; s/\n$//; s/^[ \t]+//; $num_lines++;
$bslash = s/^\\//;
($sum, $modesym, $fname) =
/^([\da-fA-F]+)[ \t]([ *?^])([^\0]*)/;
$alg = defined $sum ? $len2alg{length($sum)} : undef;
$fname = unescape($fname) if defined $fname && $bslash;
if (grep { ! defined $_ } ($alg, $sum, $modesym, $fname)) {
$alg = 1 unless defined $alg;
warn("shasum: $checkfile: $.: improperly " .
"formatted SHA$alg checksum line\n") if $warn;
$fmt_errs++;
next;
}
$fname =~ s/\r$// unless -e $fname;
$rsp = "$fname: "; $num_files++;
($binary, $portable, $text, $BITS) =
map { $_ eq $modesym } ('*', '?', ' ', '^');
unless ($digest = sumfile($fname)) {
$rsp .= "FAILED open or read\n";
$err = 1; $read_errs++;
}
else {
if (lc($sum) eq $digest) { $rsp .= "OK\n" }
else { $rsp .= "FAILED\n"; $err = 1; $match_errs++ }
}
print $rsp unless $status;
}
close(FH);
unless ($num_files) {
$alg = 1 unless defined $alg;
warn("shasum: $checkfile: no properly formatted " .
"SHA$alg checksum lines found\n");
$err = 1;
}
elsif (! $status) {
warn("shasum: WARNING: $fmt_errs line" . ($fmt_errs>1?
's are':' is') . " improperly formatted\n") if $fmt_errs;
warn("shasum: WARNING: $read_errs listed file" .
($read_errs>1?'s':'') . " could not be read\n") if $read_errs;
warn("shasum: WARNING: $match_errs computed checksum" .
($match_errs>1?'s':'') . " did NOT match\n") if $match_errs;
}
return($err == 0);
}
## Verify or compute SHA checksums of requested files
my($file, $digest);
my $STATUS = 0;
for $file (@ARGV) {
if ($check) { $STATUS = 1 unless verify($file) }
elsif ($digest = sumfile($file)) {
if ($file =~ /[\n\\]/) {
$file =~ s/\\/\\\\/g; $file =~ s/\n/\\n/g;
$digest = "\\$digest";
}
print "$digest $modesym", "$file\n";
}
else { $STATUS = 1 }
}
exit($STATUS)