Fwd: is file open in system ? - other than lsof

[bvidinli]

the idea of eg does not work for me because,
what i do:

get list of files,
check 1st file open ?
process 1st file, (this may take several seconds... )

check 2nd file open?  i have to check it here, because 2nd file may be
opened while i process file 1
process 2nd file, (this may take several seconds... )

and so on.. ....


in this case, having list of open files at begining of processes is useless...
anyway thanks.

---------- Forwarded message ----------
From: Nick Craig-Wood <nick at craig-wood.com>
Date: 17.Nis.2008 19:30
Subject: Re: is file open in system ? - other than lsof
To: python-list at python.org


Thomas Guettler <hv at tbz-pariv.de> wrote:
 >  bvidinli schrieb:
 > > is there a way to find out if file open in system ? -
 > > please write if you know a way  other than lsof. because lsof if
slow for me.
 > > i need a faster way.
 > > i deal with thousands of files... so, i need a faster / python
way for this.
 > > thanks.
 >
 >  On Linux there are symlinks from /proc/PID/fd to the open
 >  files. You could use this:
 >
 >  #!/usr/bin/env python
 >  import os
 >  pids=os.listdir('/proc')
 >  for pid in sorted(pids):
 >       try:
 >           int(pid)
 >       except ValueError:
 >           continue
 >       fd_dir=os.path.join('/proc', pid, 'fd')
 >       for file in os.listdir(fd_dir):
 >           try:
 >               link=os.readlink(os.path.join(fd_dir, file))
 >           except OSError:
 >               continue
 >           print pid, link


Unfortunately I think that is pretty much exactly what lsof does so is
 unlikely to be any faster!

 However if you have 1000s of files to check you only need to do the
 above scan once and build a dict with all open files in whereas lsof
 will do it once per call so that may be a useful speedup.

 Eg

 ------------------------------------------------------------

import os
 pids=os.listdir('/proc')

open_files = {}

for pid in sorted(pids):
     try:
         int(pid)
     except ValueError:
         continue
     fd_dir=os.path.join('/proc', pid, 'fd')

     try:
         fds = os.listdir(fd_dir)
     except OSError:
         continue
     for file in fds:

         try:
             link=os.readlink(os.path.join(fd_dir, file))
         except OSError:
             continue

         if not os.path.exists(link):
             continue
         open_files.setdefault(link, []).append(pid)

 for link in sorted(open_files.keys()):
    print "%s : %s" % (link, ", ".join(map(str, open_files[link])))
 ------------------------------------------------------------


 You might want to consider http://pyinotify.sourceforge.net/ depending
 on exactly what you are doing...


 --
 Nick Craig-Wood <nick at craig-wood.com> -- http://www.craig-wood.com/nick

--
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İ.Bahattin Vidinli
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