Saving space thread

[MrMoo]

Ok, here's a thread for detailing saving space, albeit tiny amounts.

Here is a starter, save 40KB by using minigzip instead of gzip, gzip is only used in decompressing the zoneinfo file and during image install so:

exec('/usr/bin/tar -tzf /usr/share/zoneinfo.tgz', $timezonelist);

becomes:

exec('/bin/cat /tmp/zoneinfo.tgz | /usr/bin/minigzip -d | /usr/bin/tar tf -', $timezonelist);

:D

[MrMoo]

All binaries for embedded platforms should have debug information removed by strip, this usually happens via "install -s" in the install scripts.  However a couple more extra KB can be squeezed out using the following:

# ls -l
-r-xr-xr-x  1 root  wheel  827500 Jun 30 23:11 python
# strip --remove-section=.note --remove-section=.comment python
# ls -l
-r-xr-xr-x  1 root  wheel  823968 Jun 30 23:11 python

:P

[sullrich]

Yes, we made this change weeks ago, thanks.

[MrMoo]

Three scripts, subtle modifications to m0n0's mklibs.pl:

used_libs.pl:  same as mklibs.pl but smaller

#!/usr/bin/perl

$dir = 'freesbie-fs';

use File::Find;

# check_libs(path)
sub check_libs {
        $mode = stat[2];
        @libs{`/usr/bin/ldd -f "%p\n" $_ 2>/dev/null`} = () if (-f $_);
}

# walk the directory tree
find(\&check_libs, $dir);

print sort keys %libs;

#alternative: strip leading slash
#print map { substr($_, 1); } sort keys %libs;

blame_libs.pl:  which binaries require each library

#!/usr/bin/perl

$dir = 'freesbie-fs';

use File::Find;

# check_libs(path)
sub check_libs {
        $mode = stat[2];
        if (-f $_) {
                foreach $lib (`/usr/bin/ldd -f "%p\n" $_ 2>/dev/null`) {
                        chop($lib);
                        $libs{$lib} = [] unless (exists $libs{$lib});
                        push @{ $libs{$lib} }, $_;
                }
        }
}

# walk the directory tree
find(\&check_libs, $dir);

foreach $lib (sort keys %libs) {
        print "$lib:\n";
        foreach (sort @{ $libs{$lib} }) {
                print "\t$_\n";
        }
        print "\n";
}
[/code]

[b]unused_libs.pl[/b]:  opposite of used_libs.pl attempting iterative recursion on dependencies.
[code]
#!/usr/bin/perl

$dir = 'freesbie-fs';

use File::Find;

# check_libs(path)
sub check_libs {
        $mode = stat[2];
        if (-f $_ && ! -l $_) {
                $fname = substr($File::Find::name, length($dir));
                if (/\.so(\.|$)/) {
                        $liblist{$fname} = ();
                } else {
                        $nonlist{$fname} = ();
                }

                foreach $lib (`/usr/bin/ldd -f "%p\n" $_ 2>/dev/null`) {
                        chop($lib);
                        $lib = readlink($lib) if (-l $lib);
                        $libs{$lib}{$fname} = ();
                }
        }
}

# walk the directory tree
find(\&check_libs, $dir);

$pass = 0;
do {
        $pass++;
        $pending = 0;
#       print "pass $pass\n";
        foreach $lib (sort keys %liblist) {
                $count = (exists $libs{$lib}) ? scalar keys %{ $libs{$lib} } : 0;
                if ($count == 0) {
#                       print "\t$lib\n";
                        delete $liblist{$lib};
                        $unusedlist{$lib} = ();
                        foreach $lib2 (sort keys %liblist) {
                                if (exists $libs{$lib2}{$lib}) {
#                                       print "\t\t$lib2\n";
                                        delete $libs{$lib2}{$lib};
                                        $pending++;
                                }
                        }
                        next;
                }
        }
} while ($pending > 0);

#print "unused libraries:\n\n";
foreach (sort keys %unusedlist) {
        print "$_\n";
}
[/code]