File Coverage

lib/File/Mountpoint.pm

Criterion	Covered	Total	%
statement	35	35	100.0
branch	9	10	90.0
condition	3	6	50.0
subroutine	7	7	100.0
pod	1	1	100.0
total	55	59	93.2

# Copyright (c) 2008  Joshua Hoblitt
#
# $Id: Mountpoint.pm,v 1.5 2008/09/30 06:58:06 jhoblitt Exp $

package File::Mountpoint;

use strict;

our $VERSION = '0.01';

use base qw( Exporter );

use Carp;
use File::stat qw( :FIELDS );
use Fcntl qw( :mode );
use File::Spec;

our @EXPORT_OK = qw( is_mountpoint );

sub is_mountpoint
{
# running mountpoint on /tmp yields:
#   lstat("/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=28672, ...}) = 0
#   stat("/tmp/..", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
# running mountpoint on /tmp/ yields:
#   lstat("/tmp/", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=28672, ...}) = 0
#   stat("/tmp//..", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0

# $ mountpoint /tmp/asdf
# mountpoint: /tmp/asdf: No such file or directory
# $ mountpoint /tmp/binutils-2.18.tar.bz2
# mountpoint: /tmp/binutils-2.18.tar.bz2: not a directory
# $ mountpoint /tmp
# /tmp is not a mountpoint

    my $path = shift;

    return unless defined $path;

    # verbose - currnetly unused
    my $verbose;

    # run lstat() on the path
    my $ls = lstat($path);

    # check to see if the path exists
    unless (defined $ls) {
        croak "is_mountpoint: $path: No such file or directory";
    }

    # check to make sure that the path exists and is a directory
    unless (S_ISDIR($st_mode)) {
        croak "is_mountpoint: $path: not a directory";
    }

    # store the lstat() device and inode
    my $ls_dev = $st_dev;
    my $ls_ino = $st_ino;

    # append /.. to the path and run stat() on it
    stat(File::Spec->catdir($path, "/.."));

    # store the stat() device
    my $s_dev = $st_dev;
    my $s_ino = $st_ino;

    # compare the lstat() and stat() devs
# based directly on code from mountpoint.c
    unless (($ls_dev != $s_dev) || ($ls_dev == $s_dev && $ls_ino == $s_ino)) {
        carp "is_mounpoint: $path is not a mountpoint" if $verbose;
        return;
    }

    return 1;
}


1;

__END__