progbar.py

#!/usr/bin/python
import sys, os

USAGE="""progbar.py PROCESS_ID [FILE_DESCRIPTOR_NUMBER]

Usage:

  progbar.py PROCESS_ID

    Prints all file descriptor numbers along with the location of
    each.

  progbar.py PROCESS_ID FILE_DESCRIPTOR

"""


if len(sys.argv) == 2:
    # Case 1: Print all file descriptor numbers and filenames.

    pid = sys.argv[1]
    fd_dir = os.path.join('/proc', pid, 'fd')
    fds = os.listdir(fd_dir)
    for fd in fds:
        print fd, "=>", os.readlink(os.path.join(fd_dir, fd))

elif len(sys.argv) == 3:
    # Case 2: Print the location of the file pointer, this file size,
    # and the percentage of the file behind the file pointer.

    pid = sys.argv[1]
    fd = sys.argv[2]

    # step 1: get current location
    fdinfo_filename = os.path.join('/proc', pid, 'fdinfo', fd)
    fdinfo_handle = file(fdinfo_filename)
    location = int(fdinfo_handle.readlines()[0].split()[1])
    fdinfo_handle.close()

    # step 2: get total size.
    file_path = os.readlink(os.path.join('/proc', pid, 'fd', fd))
    size = os.stat(file_path).st_size

    # report
    print location, "/", size
    print "%.2f%%" % (float(location)/float(size)*100)
    
else:
    # Case 3: Print usage and exit
    print USAGE