=head1 SYNOPSIS
-B<pristine-gz> [-v] gengz delta file
-B<pristine-gz> [-v] gendelta file.gz delta
+B<pristine-gz> [-vd] gengz delta file
+B<pristine-gz> [-vd] gendelta file.gz delta
=head1 DESCRIPTION
identical to the original.
This approach will work in the vast majority of cases. If it doesn't work,
-no delta will be generated. Please file bug reports.
+no delta will be generated.
=head1 OPTIONS
Verbose mode, show each command that is run.
+=item -d
+
+Debug mode.
+
=head1 AUTHOR
Joey Hess <joeyh@debian.org>,
use warnings;
use strict;
use File::Temp;
-use File::Path;
use Getopt::Long;
+use File::Basename qw/basename/;
+
+use constant GZIP_DEBUG => 1;
+
+# magic identification
+use constant GZIP_ID1 => 0x1F;
+use constant GZIP_ID2 => 0x8B;
+
+# compression methods, 0x00-0x07 are reserved
+use constant GZIP_METHOD_DEFLATE => 0x08;
+
+# flags
+use constant {
+ GZIP_FLAG_FTEXT => 0,
+ GZIP_FLAG_FHCRC => 1,
+ GZIP_FLAG_FEXTRA => 2,
+ GZIP_FLAG_FNAME => 3,
+ GZIP_FLAG_FCOMMENT => 4,
+ # the rest are reserved
+};
+# compression level
+use constant {
+ GZIP_COMPRESSION_NORMAL => 0,
+ GZIP_COMPRESSION_BEST => 2,
+ GZIP_COMPRESSION_FAST => 4,
+};
+# operating systems
+use constant {
+ GZIP_OS_MSDOS => 0,
+ GZIP_OS_AMIGA => 1,
+ GZIP_OS_VMS => 2,
+ GZIP_OS_UNIX => 3,
+ GZIP_OS_VMCMS => 4,
+ GZIP_OS_ATARI => 5,
+ GZIP_OS_HPFS => 6,
+ GZIP_OS_MACINTOSH => 7,
+ GZIP_OS_ZSYSTEM => 8,
+ GZIP_OS_CPM => 9,
+ GZIP_OS_TOPS => 10,
+ GZIP_OS_NTFS => 11,
+ GZIP_OS_QDOS => 12,
+ GZIP_OS_RISCOS => 13,
+ GZIP_OS_UNKNOWN => 255,
+};
my $verbose=0;
+my $debug=0;
sub usage {
print STDERR "Usage: pristine-gz [-v] gengz delta file\n";
print STDERR " pristine-gz [-v] gendelta file.gz delta\n";
}
+sub debug {
+ print "debug: @_\n" if $debug;
+}
+
sub vprint {
print "pristine-gz: @_\n" if $verbose;
}
TMPDIR => 1, CLEANUP => 1);
}
+sub readGzip($) {
+ my $filename = shift;
+ my $chars;
+
+ open(GZIP, "< $filename")
+ or die("Could not open '$filename' for reading: $!\n");
+
+ if (read(GZIP, $chars, 10) != 10) {
+ die("Unable to read from input\n");
+ }
+
+ my ($id1, $id2, $method, $flags, $timestamp, $level, $os, $name)
+ = (unpack("CCCb8VCC", $chars), '');
+
+ if ($id1 != GZIP_ID1 || $id2 != GZIP_ID2 || $method != GZIP_METHOD_DEFLATE) {
+ die("This is not a valid GZip archive.\n");
+ }
+ my @flags = split(//, $flags);
+
+ if ($flags[GZIP_FLAG_FNAME]) {
+ # read a null-terminated string
+ $name .= $chars
+ while (read(GZIP, $chars, 1) == 1 && ord($chars) != 0);
+ }
+ close(GZIP);
+
+ return (\@flags, $timestamp, $level, $os, $name);
+}
+
+sub debugGzip($$$$$) {
+ my ($flags, $timestamp, $level, $os, $name) = @_;
+ my @flags = @$flags;
+
+ if ($os != GZIP_OS_UNIX) {
+ debug("Unknown Operating System: $os");
+ }
+ if ($timestamp > 0) {
+ debug("Created on ", scalar localtime $timestamp);
+ }
+
+ if ($level == GZIP_COMPRESSION_NORMAL) {
+ debug("Normal compression");
+ } elsif ($level == GZIP_COMPRESSION_BEST) {
+ debug("Maximum/Slower compression");
+ } elsif ($level == GZIP_COMPRESSION_FAST) {
+ debug("Minimum/Faster compression");
+ } else {
+ debug("Unknown/invalid compression level: $level");
+ }
+
+ if ($flags[GZIP_FLAG_FNAME]) {
+ debug("Has name: '$name')");
+ }
+}
+
+sub findGzipArgs($$$) {
+ my ($flags, $timestamp, $level) = @_;
+ my @flags = @$flags;
+
+ my @args;
+ unless ($flags[GZIP_FLAG_FNAME]) {
+ push @args, '-n';
+ push @args, '-M' if $timestamp;
+ } else {
+ push @args, '-m'
+ unless($timestamp);
+ }
+
+ if ($level == GZIP_COMPRESSION_BEST) {
+ push @args, '-9'
+ } elsif ($level == GZIP_COMPRESSION_FAST) {
+ push @args, '-1'
+ }
+
+ return @args;
+}
+
+sub compareFiles($$) {
+ my ($old, $new) = (shift, shift);
+ system('cmp', '-s', $old, $new);
+
+ if ($? == -1 || $? & 127) {
+ die("Failed to execute cmp: $!\n");
+ }
+
+ return $? >> 8;
+}
+
+sub gunzip($$) {
+ my ($filename, $name) = (shift, shift);
+ doit('gunzip', '-N', $filename);
+ if (-e $filename) {
+ die("gunzip failed, aborting");
+ } elsif ($name && -e $name) {
+ # original filename because we passed -N to gunzip
+ return $name;
+ } else {
+ $filename =~ s/\.gz$//;
+ unless (-e $filename) {
+ die("gunzip succeded but I can't find the filename");
+ }
+ return $filename;
+ }
+}
+
+sub gzip($@) {
+ my ($filename, @args) = @_;
+
+ doit(@args, $filename);
+ $filename .= '.gz';
+ unless (-e $filename) {
+ die("gzip failed, aborting");
+ }
+ return $filename;
+}
+
+sub cycleGzip($$@) {
+ my ($filename, $name, @args) = @_;
+
+ $filename = gunzip($filename, $name);
+ $filename = gzip($filename, @args);
+
+ return $filename;
+}
+
sub reproducegz {
- my $gzfile=shift;
+ my $orig=shift;
+ my $wd=shift;
+
+ # copy the original .gz to the newly created temporary directory
+ my $tmp = "$wd/".basename($orig);
+ doit("cp", $orig, $tmp);
+
+ # read fields from gzip headers
+ my ($flags, $timestamp, $level, $os, $name) = readGzip($tmp);
+ debug("Examining $orig", $name ? " (real: $name)" : '');
+ $name = "$wd/$name" if $name;
+
+ # try to guess the gzip arguments that are needed by the header
+ # information
+ my @args = findGzipArgs($flags, $timestamp, $level);
+
+ # for 98% of the cases the simple heuristic above works
+ debug("Trying 'gzip ", join(' ', @args), "'...");
+ $tmp = cycleGzip($tmp, $name, 'gzip', @args);
+ unless (compareFiles($orig, $tmp)) {
+ return 0, 'gzip', @args;
+ }
+
+ # some archives have an Operating System flag different than Unix
+ # XXX: if they're the same, just replace the bit
+ #if ($os != GZIP_OS_UNIX) {
+ # debug("Unknown Operating System: $os");
+ #}
+
+ # some .gz are created using --rsyncable -- this is a Debian-specific
+ # option however and it's not very popular
+ debug("Trying with --rsyncable...");
+ $tmp = cycleGzip($tmp, $name, 'gzip', @args, '--rsyncable');
+ unless (compareFiles($orig, $tmp)) {
+ return 0, 'gzip', @args, '--rsyncable';
+ }
- return "gzip", "-9"; # FIXME
+ # many of the .gz out there are created using the BSD version of gzip
+ # which is using the zlib library; try with our version of bsd-gzip
+ # with added support for the undocumented GNU gzip options -m and -M
+ debug("Trying with bsd-gzip...");
+ $tmp = cycleGzip($tmp, $name, 'bsd-gzip', @args);
+
+ unless (compareFiles($orig, $tmp)) {
+ return 0, 'bsd-gzip', @args;
+ }
+
+ # apparently, there is an old version of bsd-gzip (or a similar tool
+ # based on zlib) that creates gz using maximum compression (-9) but
+ # does not indicate so in the headers. surprisingly, there are many
+ # .gz out there
+ debug("Trying with buggy variant of bsd-gzip...");
+ $tmp = cycleGzip($tmp, $name, 'bsd-gzip', @args, '--no-xfl');
+
+ unless (compareFiles($orig, $tmp)) {
+ return 0, 'bsd-gzip', @args, '--no-xfl';
+ }
+
+ print STDERR("pristine-gz failed to reproduce build of $orig\n");
+ print STDERR("(Please file a bug report.)\n");
+ exit 1;
}
sub gengz {
my $sourcedir="$tempdir/tmp";
doit("mkdir $sourcedir");
- my ($program, $params)=reproducegz($gzfile);
+ my ($osflag, $program, @params)=reproducegz($gzfile, $tempdir);
open(OUT, ">", "$tempdir/version") || die "$!";
print OUT "1.1\n";
print OUT "$program\n";
close OUT;
open(OUT, ">", "$tempdir/params") || die "$!";
- print OUT "$params\n";
+ print OUT "@params\n";
close OUT;
doit("tar", "czf", $delta, "-C", $tempdir, @files);
}
-if (! GetOptions("verbose!" => \$verbose) || @ARGV != 3) {
+Getopt::Long::Configure("bundling");
+if (! GetOptions("v|verbose!" => \$verbose, "d|debug!" => \$debug) || @ARGV != 3) {
usage();
exit 1;
}
projects / tools / pristine-tar.git / commitdiff