Get fat32 attributes with python

Question

How i can get fat32 attributes (like archived, hidden...) in linux without spawning a new process with fatattr utility call ? May be there is python binding for it or for linux/fs functions (fat_ioctl_get_attributes, http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/fs/fat/file.c). Or maybe it can be done with python-xattr ?

Answer 1

As you can see in the function name, the kernel function fat_ioctl_get_attributes is called from userspace via an ioctl, and I'm not aware of any other binding. Therefore, you can simply read the attributes by calling ioctl yourself, like this:

import array
import fcntl
import os

FAT_IOCTL_GET_ATTRIBUTES = 0x80047210
FATATTR_BITS = 'rhsvda67'

def get_fat_attrs(fn):
    fd = os.open(fn, os.O_RDONLY)
    try:
        buf = array.array('L', [0])
        try:
            fcntl.ioctl(fd, FAT_IOCTL_GET_ATTRIBUTES, buf, True)
        except IOError as ioe:
            if ioe.errno == 25: # Not a FAT volume
                return None
            else:
                raise

        return buf[0]
    finally:
        os.close(fd)

if __name__ == '__main__':
    import sys
    for fn in sys.argv[1:]:
        attrv = get_fat_attrs(fn)
        if attrv is None:
            print(fn + ': Not on a FAT volume')
            continue
        s = ''.join((fb if (1 << idx) & attrv else ' ')
                    for idx,fb in enumerate(FATATTR_BITS))
        print(fn + ': ' + s)