Re: patch for fusermount: Not enough command line arguments

[Alistair Crooks <agc%pkgsrc.org@localhost>]

On Thu, Apr 16, 2009 at 09:53:23AM -0500, Jeremy C. Reed wrote:
> Trying to unmount a filesystem...
> 
> $ mount | grep puffs
> /dev/puffs on /home/reed/hammer/fusehammer/mnt type 
> puffs|refuse:hammerdisk.raw (nosuid, nodev, mounted by reed)
> 
> $ fusermount -u /home/reed/hammer/fusehammer/mnt 
> fusermount: Not enough command line arguments
> Usage: fusermount [-c] [-d name] [-h] [-p] [-u] [-x] mountpoint...
>         -c      use kernel cache
>         -d name use name in mount information
>         -h      print help information
>         -p      check file permissions
>         -u      unmount mount point(s)
>         -x      allow access to mortal (non-root) users
> 
> Even man page suggests is correct syntax:
> 
> SYNOPSIS
>      fusermount [-chpVx] [-d name] refuseoptions
>      fusermount -u mountpoint(s)
> 
> So I looked at code and added debugging:
> 
>         if (optind >= argc - 2) {
> printf("optind = %d, argc = %d\n", optind, argc); 
>  
>                 warnx("Not enough command line arguments");
>                 usage(*argv);
>                 exit(EXIT_FAILURE);
>         }
> 
> optind = 2, argc = 3
> 
> optind is the index for next argument.
> 
> So my workaround is to add two more junk arguments to the command line:
> 
> $ fusermount -u /home/reed/hammer/fusehammer/mnt  JUNK1 JUNK2   
> fusermount: can't unmount `JUNK1': No such file or directory
> fusermount: can't unmount `JUNK2': No such file or directory
> 
> Okay if I commit the following?
> 
> Index: fusermount.c
> ===================================================================
> RCS file: /cvsroot/src/usr.sbin/fusermount/fusermount.c,v
> retrieving revision 1.3
> diff -u -r1.3 fusermount.c
> --- fusermount.c      21 Jul 2008 13:36:58 -0000      1.3
> +++ fusermount.c      16 Apr 2009 14:48:39 -0000
> @@ -134,7 +134,7 @@
>                       exit(EXIT_FAILURE);
>               }
>       }
> -     if (optind >= argc - 2) {
> +     if (action != ActionUnmount && optind >= argc - 2) {
>               warnx("Not enough command line arguments");
>               usage(*argv);
>               exit(EXIT_FAILURE);
> 
> 
> 
> (By the way if you attempt to unmount something already unmounted you get
> "Operation not permitted".)
> 

It might be better to do something like:

        if ((action == ActionMount && optind >= argc - 2) ||
            (action == ActionUnmount && optind >= argc)) {
                warn...
        }

i.e. check for out of arguments in unmount case as well.

And, no, I have no idea why the fusermount arguments are so... esoteric.

Regards,
Alistair