Switch RomFS (IStorage) -> Files

switch_romfs.py

from struct import unpack as up
import sys, os

dirs, files = None, None

def read_at(fp, off, len):
    fp.seek(off)
    return fp.read(len)

def read_u8(fp, off):
    return up('<B', read_at(fp, off, 1))[0]

def read_u16(fp, off):
    return up('<H', read_at(fp, off, 2))[0]

def read_u32(fp, off):
    return up('<I', read_at(fp, off, 4))[0]

def read_u64(fp, off):
    return up('<Q', read_at(fp, off, 8))[0]

def read_filename(fp, off, l):
    if l == 0:
        return ''
    s = read_at(fp, off, l)
    if '\0' in s:
        s = s[:s.index('\0')]
    return s

def dump_file(name, offset, size):
    global archive, out_dir
    path = os.path.join(out_dir, name[1:])
    print 'Dumping %s (%012X-%012X) to %s...' % (name, offset, offset+size, path)
    archive.seek(offset)
    with open(path, 'wb') as f:
        ofs = 0
        sz = 0x800000
        while ofs < size:
            if size - ofs < sz:
                sz = size - ofs
            f.write(archive.read(sz))
            ofs += sz
    print 'Dumped!'

def parse_file(off, path = ''):
    global archive, dirs_off, files_off, fdata_off
    sibling = 0
    while sibling != 0xFFFFFFFF:
        archive.seek(files_off + off)
        (parent, sibling, ofs, size, hsh, namelen) = up('<IIQQII', archive.read(0x20))
        name = read_filename(archive, files_off + off + 0x20, namelen)
        filepath = '%s%s' % (path, name)
        dump_file(filepath, fdata_off+ofs, size)
        off = sibling

def parse_dir(off, path = ''):
    global archive, dirs_off, files_off, fdata_off, out_dir
    archive.seek(dirs_off + off)
    (sibling, child, file, hsh, namelen) = up('<IIIII', archive.read(0x14))
    name = read_filename(archive, dirs_off + off + 0x14, namelen)
    if path:
        newpath = '%s%s/' % (path, name)
    else:
        newpath = '%s/' % name
    dirp = os.path.dirname(os.path.join(out_dir, newpath[1:])).replace('/', os.path.sep)
    if not os.path.exists(dirp):
        os.mkdir(dirp)
    if file != 0xFFFFFFFF:
        parse_file(file, newpath)
    if sibling != 0xFFFFFFFF:
        parse_dir(sibling, path)
    if child != 0xFFFFFFFF:
        parse_dir(child, newpath)

def main(argc, argv):
    if argc != 3:
        print 'Usage: %s in_file out_dir' % argv[0]
        return
    global archive, dirs_off, files_off, fdata_off
    try:
        archive = open(argv[1], 'rb')
        if read_u64(archive, 0) != 0x50:
            print 'Error: Invalid archive.'
            return
        dirs_off = read_u64(archive, 0x18)+4
        files_off = read_u64(archive, 0x38)
        fdata_off = read_u64(archive, 0x48)
        print 'Directory Metadata at %08X' % dirs_off
        print 'File Metadata at %08X' % files_off
    except:
        print 'Failed to open %s.' % argv[1]
        return

    global out_dir
    out_dir = argv[2]

    sys.setrecursionlimit(100000)
    parse_dir(0)

if __name__ == '__main__':
    main(len(sys.argv), sys.argv)

Thanks a lot for this.
I installed Python 3.6 and did this in Windows' CMD:

cd /d "d:\switchdump"
switch_romfs.py XXX_romfs.istorage targetfolder

But then I got this error:

  File "D:\switchdump\switch_romfs.py", line 33
    print 'Dumping %s (%012X-%012X) to %s...' % (name, offset, offset+size, path
)
                                            ^
SyntaxError: invalid syntax

I would be grateful for any help to get this to run at all.

This is python2 code.

Print statements without () are not valid in python3.

So this script can't get the RomFS from XCI files that are now showing up. Shame...