--- /dev/null
+#!/usr/bin/env perl
+
+use strict;
+no strict qw(refs);
+
+use Carp ();
+local $SIG{'__WARN__'} = \&Carp::cluck;
+
+use Fuse;
+use Fcntl qw(:mode);
+use Errno qw(:POSIX);
+use POSIX;
+
+my $fioc_size = 0;
+use constant FIOC_NAME => 'fioc';
+my $fioc_buf = '';
+use constant FIOC_NONE => 0;
+use constant FIOC_ROOT => 1;
+use constant FIOC_FILE => 2;
+
+sub _IOC_NRBITS { 8 }
+sub _IOC_NRMASK { ( 1 << &_IOC_NRBITS ) - 1 }
+sub _IOC_NRSHIFT { 0 }
+
+sub _IOC_TYPEBITS { 8 }
+sub _IOC_TYPEMASK { ( 1 << &_IOC_TYPEBITS ) - 1 }
+sub _IOC_TYPESHIFT { &_IOC_NRSHIFT + &_IOC_NRBITS }
+
+sub _IOC_SIZEBITS { ( POSIX::uname() )[4] =~ /^i[3-6]86|x86_64$/ ? 14 : 13 }
+sub _IOC_SIZEMASK { ( 1 << &_IOC_SIZEBITS ) - 1 }
+sub _IOC_SIZESHIFT { &_IOC_TYPESHIFT + &_IOC_TYPEBITS }
+
+sub _IOC_DIRBITS { 32 - &_IOC_NRBITS - &_IOC_TYPEBITS - &_IOC_SIZEBITS }
+sub _IOC_DIRMASK { ( 1 << &_IOC_DIRBITS ) - 1 }
+sub _IOC_DIRSHIFT { &_IOC_SIZESHIFT + &_IOC_SIZEBITS }
+
+sub _IOC_NONE { ( POSIX::uname() )[4] =~ /^i[3-6]86|x86_64$/ ? 0 : 1 }
+sub _IOC_WRITE { ( POSIX::uname() )[4] =~ /^i[3-6]86|x86_64$/ ? 1 : 4 }
+sub _IOC_READ { ( POSIX::uname() )[4] =~ /^i[3-6]86|x86_64$/ ? 2 : 2 }
+
+sub _IOC ($$$$) {
+ ( $_[0] << &_IOC_DIRSHIFT ) | ( ord( $_[1] ) << &_IOC_TYPESHIFT ) |
+ ( $_[2] << &_IOC_NRSHIFT ) | ( $_[3] << &_IOC_SIZESHIFT );
+}
+
+sub _IO ($$) { &_IOC( &_IOC_NONE, $_[0], $_[1], 0 ) }
+sub _IOR ($$$) { &_IOC( &_IOC_READ, $_[0], $_[1], $_[2] ) }
+sub _IOW ($$$) { &_IOC( &_IOC_WRITE, $_[0], $_[1], $_[2] ) }
+sub _IOWR ($$$) { &_IOC( &_IOC_READ | &_IOC_WRITE, $_[0], $_[1], $_[2] ) }
+
+sub FIOC_GET_SIZE { _IOR('E', 0, 4); }
+sub FIOC_SET_SIZE { _IOW('E', 1, 4); }
+
+sub fioc_resize {
+ my ($size) = @_;
+ print 'called ', (caller(0))[3], "\n";
+ return 0 if $size == $fioc_size;
+
+ if ($size < $fioc_size) {
+ $fioc_buf = substr($fioc_buf, 0, $size);
+ }
+ else {
+ $fioc_buf .= "\0" x ($size - $fioc_size);
+ }
+ $fioc_size = $size;
+ return 0;
+}
+
+sub fioc_expand {
+ my ($size) = @_;
+ print 'called ', (caller(0))[3], "\n";
+ if ($size > $fioc_size) {
+ return fioc_resize($size);
+ }
+ return 0;
+}
+
+sub fioc_file_type {
+ my ($path) = @_;
+ print 'called ', (caller(0))[3], "\n";
+ return FIOC_ROOT if $path eq '/';
+ return FIOC_FILE if $path eq '/' . FIOC_NAME;
+ return FIOC_NONE;
+}
+
+sub fioc_getattr {
+ my ($path) = @_;
+ print 'called ', (caller(0))[3], "\n";
+ my @stbuf = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+
+ $stbuf[4] = $<;
+ $stbuf[5] = (split(/\s+/, $())[0];
+ $stbuf[8] = $stbuf[9] = time();
+
+ my $type = fioc_file_type($path);
+ if ($type == FIOC_ROOT) {
+ $stbuf[2] = S_IFDIR | 0755;
+ $stbuf[3] = 2;
+ }
+ elsif ($type == FIOC_FILE) {
+ $stbuf[2] = S_IFREG | 0644;
+ $stbuf[3] = 1;
+ $stbuf[7] = $fioc_size;
+ }
+ else {
+ return -&ENOENT;
+ }
+ return @stbuf;
+}
+
+sub fioc_open {
+ my ($path, $flags, $info) = @_;
+ print 'called ', (caller(0))[3], "\n";
+
+ if (fioc_file_type($path) != FIOC_NONE) {
+ return 0;
+ }
+ return -&ENOENT;
+}
+
+sub fioc_read {
+ my ($path, $size, $offset) = @_;
+ print 'called ', (caller(0))[3], "\n";
+
+ return -&EINVAL if fioc_file_type($path) != FIOC_FILE;
+
+ if ($offset > $fioc_size) {
+ return q{};
+ }
+
+ if ($size > $fioc_size - $offset) {
+ $size - $fioc_size - $offset;
+ }
+
+ return substr($fioc_buf, $offset, $size);
+}
+
+sub fioc_write {
+ my ($path, $data, $offset) = @_;
+ print 'called ', (caller(0))[3], "\n";
+
+ return -&EINVAL if fioc_file_type($path) != FIOC_FILE;
+
+ if (fioc_expand($offset + length($data))) {
+ return -&ENOMEM;
+ }
+
+ substr($fioc_buf, $offset, length($data), $data);
+ return length($data);
+}
+
+sub fioc_truncate {
+ my ($path, $size) = @_;
+ print 'called ', (caller(0))[3], "\n";
+
+ return -&EINVAL if fioc_file_type($path) != FIOC_FILE;
+
+ return fioc_resize($size);
+}
+
+sub fioc_readdir {
+ my ($path, $offset) = @_;
+ print 'called ', (caller(0))[3], "\n";
+
+ return -&EINVAL if fioc_file_type($path) != FIOC_ROOT;
+
+ return ('.', '..', FIOC_NAME, 0);
+}
+
+sub fioc_ioctl {
+ my ($path, $cmd, $flags, $data) = @_;
+ print 'called ', (caller(0))[3], "\n";
+ $cmd = unpack('L', pack('l', $cmd));
+
+ print("fioc_ioctl(): path is \"$path\", cmd is $cmd, flags is $flags\n");
+ return -&EINVAL if fioc_file_type($path) != FIOC_FILE;
+
+ return -&ENOSYS if $flags & 0x1;
+
+ if ($cmd == FIOC_GET_SIZE) {
+ print "handling FIOC_GET_SIZE\n";
+ return(0, pack('L', $fioc_size));
+ }
+ elsif ($cmd == FIOC_SET_SIZE) {
+ print "handling FIOC_SET_SIZE\n";
+ fioc_resize(unpack('L', $data));
+ return 0;
+ }
+
+ return -&EINVAL;
+}
+
+croak("Fuse doesn't have ioctl") unless Fuse::fuse_version() >= 2.8;
+
+Fuse::main(
+ 'mountpoint' => $ARGV[0],
+ 'getattr' => 'main::fioc_getattr',
+ 'readdir' => 'main::fioc_readdir',
+ 'truncate' => 'main::fioc_truncate',
+ 'open' => 'main::fioc_open',
+ 'read' => 'main::fioc_read',
+ 'write' => 'main::fioc_write',
+ 'ioctl' => 'main::fioc_ioctl');