Re: RFC - how to quota special characters in filenames in /proc files

Re: RFC - how to quota special characters in filenames in /proc files

[Andries.Brouwer]

    From: Neil Brown <neilb@cse.unsw.edu.au>

    I am interested in opinions that people might have on how to quote
    special characters in filenames in files in /proc.

    Is there any convention already used in some other part of the
    kernel?

/proc/mounts does what mount does - it uses octal escapes:

# mount /dev/sr0 "/a b" -r -t iso9660
# mount | tail -1
/dev/sr0 on /a b type iso9660 (ro)
# cat /proc/mounts | tail -1
/dev/sr0 /a\040b iso9660 ro 0 0
#

Andries

RFC - how to quota special characters in filenames in /proc files

[Neil Brown]

Greetings.

I am interested in opinions that people might have on how to quote
special characters in filenames in files in /proc.

The particular filenames of interest are those in
     /proc/fs/nfs/exports

This file lists the directories that have been exported, what hosts
they are exported to, and what export options apply.

The lines are made of space-sparated fields.  The first field is the
directory name.

So what happens when you export a directory which has a space in it's
name?  Currently this doesn't work too well.

My preference is to replace all control characters, spaces, DEL, and '%'
with a %hex string much like the special character quoting in
URLs.

Other alternatives that I don't like is to preceed special characters
with '\'  or to use =hex instead of %hex, like MIME encoding does.

So:
  is there any good reason why I should choose something other than %hex?  
  is there any convention already used in some other part of the
    kernel.

In the longer term it would probably be better to use a directory
rather than a file, and present all file names as symlinks so quoting
isn't needed.  However I don't see that as a short term solution and I
think a short term solution is needed.


Thankyou for your time.

NeilBrown