testfs.py

#!/usr/bin/env python

# step-1
# will mount an FS, but useless beyond that

import errno
import fuse
import os # import os for current uid/gid
import stat # import stat, ExampleFS_Stat class, ExampleFS.getattr
from datetime import date
import time
import datetime

fuse.fuse_python_api = ( 0, 2 )

test_dir_name = '20130622'
test_dir_path = '/' + test_dir_name
test_file_name ='test.txt'
test_file_path =test_dir_path + '/' + test_file_name

#test_file_path = '/test.txt'
test_file = 'This is a test\n by Duong\n'

now = datetime.datetime.now() #get the current datetime

# implement 
class ExampleFS_Stat( fuse.Stat ):
    def __init__( self ) :
        self.st_ino  = 0
        self.st_dev = 0
        self.st_uid = os.getuid() #get current user id
        self.st_gid = os.getgid() #get current group id
        self.st_size    = 0  #size
        self.st_atime   = time.time()  #access time
        self.st_mtime   = time.time()  #modification time
        self.st_ctime   = time.time()  #change time
        # default to read only file
        self.st_mode = stat.S_IFREG | 0400 #type and permission
        self.st_nlink = 1 #2 for dirs, 1 for files (generally)

    def dir( self, mode = 0744 ):
        self.st_mode = stat.S_IFDIR | mode
        self.st_nlink = 2

class ExampleFS( fuse.Fuse ):
    def __init__( self, *args, **kw ):
        fuse.Fuse.__init__( self, *args, **kw )

    #get the metadata
    def getattr( self, path ):

        st = ExampleFS_Stat()

        if path == '/':
            st.dir()
            return st
        
        if path == test_dir_path:
            st.dir()
            return st
        
        if path == test_file_path:
            st.st_size = len( test_file )
            st.st_mode = stat.S_IFREG | 0644
            return st

        if path == '/readme.txt':
            st.st_size = 512 * ( 2 ** 40 )  # hard code file size #increase size of file
            return st

        # if we are still here then this file doesn't exist
        return -errno.ENOENT

    def open( self, path, flags ):
        #return -errno.EACCES
        if path == test_file_path:
            print test_dir_name
            check_year = test_dir_name[0:4]
            print "Y" + check_year
            check_month = test_dir_name[4:6]
            print "M" + check_month
            check_day = test_dir_name[6:8]
            print "D" + check_day

            today = date.today()
            check_date = datetime.date( int(check_year) , int(check_month) , int(check_day) )
            print today
            print "check is"
            print check_date 
            if today > check_date :
                print "today is bigger"
            else:
                print "today is smaller"
                return -errno.EACCES
            return 0
        #return -errno.ENOENT
        return 0

    def read( self, path, size, offset ):
        if path != test_file_path:
            return -errno.ENOENT
        buffer = ''
        str_len = len( test_file )
        if offset < str_len:
            if offset + size > str_len:
                size = str_len - offset
            buffer = test_file[offset : offset + size]
        return buffer

    def readdir( self, path, offset ):    #??
        if path == '/':
            yield fuse.Direntry( '.' )
            yield fuse.Direntry( '..' )
            yield fuse.Direntry( 'readme.txt' )
            yield fuse.Direntry( test_dir_name )
        if path == test_dir_path:
            yield fuse.Direntry(test_file_name )

    def write( self, path, buffer, offset ):   # dont understand much
        global test_file    # force correct context
        if path != test_file_path:
            return -errno.ENOENT
        length = len( buffer )
        new_str = test_file[:offset] + buffer
        new_str += test_file[offset + length:]
        test_file = new_str
        return length
    
    #not work well
    def access(self, path, mode):
        # if not os.access("." + path, mode):
        return -errno.EACCES

 #   def readdir(path):
 #       if path == test_file_path:
 #       #return -errno.EACESS
 #          return 0
        
if __name__ == '__main__':
    examplefs = ExampleFS()
    args = examplefs.parse( errex = 1 )
    examplefs.main()

def access(self, path, mode):
    # if not os.access("." + path, mode):
    return -errno.EACCES