1 files changed, 117 insertions, 0 deletions
diff --git a/perl/loopback.pl b/perl/loopback.pl
new file mode 100644
index 0000000..2a8496a
--- /dev/null
+++ b/perl/loopback.pl
@@ -0,0 +1,117 @@
+#!/usr/bin/perl
+
+use strict;
+use Fuse;
+use POSIX qw(ENOENT ENOSYS EEXIST EPERM O_RDONLY O_RDWR O_APPEND O_CREAT);
+use Fcntl qw(S_ISBLK S_ISCHR S_ISFIFO);
+
+sub debug {
+	print(STDERR join(",",@_),"\n");
+}
+
+sub fixup { return "/tmp/test" . shift }
+
+sub x_getattr {
+	my ($file) = fixup(shift);
+	debug("getattr $file");
+	return -ENOENT() unless -e $file;
+	debug(stat($file));
+	return (stat($file));
+}
+
+sub x_getdir {
+	my ($dirname) = fixup(shift);
+	debug("getdir >$dirname<");
+	unless(opendir(DIRHANDLE,$dirname)) {
+		debug("ENOENT");
+		return -ENOENT();
+	}
+	debug("ok");
+	my (@files) = readdir(DIRHANDLE);
+	closedir(DIRHANDLE);
+	debug(@files);
+	return (@files, 0);
+}
+
+sub x_open {
+	my ($file) = fixup(shift);
+	debug("open flags = $_[0]");
+	my ($fd) = POSIX::open($file,@_);
+	if(!defined($fd)) {
+		debug("POSIX::open(".join(",",$file,@_).") returned undef");
+		return -ENOSYS();
+	}
+	debug("open $file = $fd");
+	return $fd if $fd < 0;
+	POSIX::close($fd);
+	debug("good: $fd");
+	return 0;
+}
+
+sub x_read {
+	my ($file,$bufsize,$off) = @_;
+	debug("read",@_);
+	my ($rv) = -ENOSYS();
+	return -ENOENT() unless -e ($file = fixup($file));
+	return -ENOSYS() unless sysopen(FILE,$file,O_RDONLY());
+	if(sysseek(FILE,$off,0)) { sysread(FILE,$rv,$bufsize); }
+	close(FILE);
+	debug("good");
+	return $rv;
+}
+
+sub x_write {
+	my ($file,$buf,$off) = @_;
+	debug("write",@_);
+	my ($rv);
+	return -ENOENT() unless -e ($file = fixup($file));
+	return -ENOSYS() unless sysopen(FILE,$file,O_RDWR()|O_APPEND()|O_CREAT());
+	if(sysseek(FILE,$off,0)) { $rv = syswrite(FILE,$buf); }
+	$rv = -ENOSYS() unless $rv;
+	close(FILE);
+	debug("good");
+	return $rv;
+}
+
+sub err { return (-shift || -$!) }
+
+sub x_readlink { return err(readlink(fixup(shift))            ); }
+sub x_unlink   { return unlink(fixup(shift)) ? 0 : -$!;          }
+sub x_rmdir    { return err(rmdir(fixup(shift))               ); }
+sub x_symlink  { return err(symlink(fixup(shift),fixup(shift))); }
+sub x_rename   { return err(rename(fixup(shift),fixup(shift)) ); }
+sub x_link     { return err(link(fixup(shift),fixup(shift))   ); }
+sub x_mkdir    { return err(mkdir(fixup(shift),shift)         ); }
+sub x_chmod    { return err(chmod(fixup(shift),shift)         ); }
+sub x_chown    { return err(chown(fixup(shift),shift,shift)   ); }
+sub x_chmod    { return err(chmod(fixup(shift),shift)         ); }
+sub x_truncate { return err(truncate(fixup(shift),shift)      ); }
+sub x_utime    { return utime($_[1],$_[2],fixup($_[0])) ? 0:-$!; }
+
+sub x_mknod {
+	# since this is called for ALL files, not just devices, I'll do some checks
+	# and possibly run the real mknod command.
+	my ($file, $modes, $dev) = @_;
+	return -EEXIST() if -e ($file = fixup($file));
+	return -EPERM() if (system("touch $file 2>/dev/null") >> 8);
+	if(S_ISBLK($modes) || S_ISCHR($modes) || S_ISFIFO($modes)) {
+		system("rm -f $file 2>/dev/null");
+		my ($chr) = 'c';
+		my ($omodes) = sprintf("%o",$modes & 0x1ff);
+		$chr = 'b' if S_ISBLK($modes);
+		if(S_ISFIFO($modes)) {
+			$chr = 'p';
+			$dev = "";
+		} else {
+			$dev = (($dev>>8) & 255) . " " . ($dev & 255);
+		}
+		system("mknod --mode=$omodes '$file' $chr $dev");
+	}
+}
+
+my ($mountpoint) = "";
+$mountpoint = shift(@ARGV) if @ARGV;
+Fuse::main(mountpoint=>$mountpoint, getattr=>\&x_getattr, readlink=>\&readlink, getdir=>\&x_getdir, mknod=>\&x_mknod,
+	mkdir=>\&x_mkdir, unlink=>\&x_unlink, rmdir=>\&x_rmdir, symlink=>\&x_symlink, rename=>\&x_rename, link=>\&x_link,
+	chmod=>\&x_chmod, chown=>\&x_chown, truncate=>\&x_truncate, utime=>\&x_utime, open=>\&x_open, read=>\&x_read, write=>\&x_write
+);