#!/usr/bin/python ########### # IMPORTS # ########### # cgi import cgi # to enable errors to be displayed in the browser: #import cgitb; cgitb.enable() # basic cgi output header print "Content-type: text/html\n" # os import os, os.path ######## # HTML # ######## def printHTMLHeader(): print """ allocated datablocks

(4) show content of allocated data blocks on HD:

""" def printHTMLFooter(): print "" ######## # MAIN # ######## # htmlheader printHTMLHeader() # get form fields formdata = cgi.FieldStorage() # filename (inside uploads/) filename = formdata.getvalue("filename", None) # amount of bytes to read bytesToRead = int(formdata.getvalue("bytes", 0)) # start postion (in bytes) for reading startToRead = int(formdata.getvalue("start", 0)) # process file... # only accept filename without "/" to avoid reading other files then in uploads/ if filename and (filename.count("/") == 0): # filename ok and file existing? filepath = os.path.join("uploads", filename) if os.path.isfile(filepath): # block size blocksize = 4096 # open file fr = file(filepath, "r") # seek position to start reading fr.seek(startToRead) # pre-read bytes = fr.read(blocksize) readBytes = len(bytes) # output table header blocksf = bytesToRead / float(blocksize) if blocksf == int(blocksf): blocks = int(blocksf) else: blocks = int(blocksf) + 1 # print print """

%d bytes on %d blocks (each max. %d bytes), starting at %d of file "%s":

""" % (bytesToRead, blocks, blocksize, startToRead, filepath) # read and output loop while bytes and readBytes <= bytesToRead: # print print """""" % (bytes) # calculate amount of bytes to read next (last block might be smaller than blocksize) bytesNow = bytesToRead - readBytes if bytesNow >= blocksize: bytesNow = blocksize # read bytes = fr.read(bytesNow) # inc readBytes = readBytes + len(bytes) #print "

%dno file with path %s

" % filepath else: print "

no filename given.

" # htmlfooter printHTMLFooter
%s