.\" $NetBSD: perfused.8,v 1.13 2019/07/06 00:45:02 gutteridge Exp $
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.\" Copyright (c) 2010 Emmanuel Dreyfus. All rights reserved.
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.Dd January 29, 2012
.Dt PERFUSED 8
.Os
.Sh NAME
.Nm perfused
.Nd PUFFS Enabled Relay to FUSE Daemon
.Sh SYNOPSIS
.Nm
.Op Fl fs
.Op Fl d Ar types
.Op Fl i fd
.Sh DESCRIPTION
.Nm
is a userland daemon implementing the FUSE kernel level API.
It creates a
.Pa /dev/fuse
socket for FUSE file system daemons to connect to.
.Nm
takes care of mounting the file system using
.Xr puffs 3 .
.Pp
When the kernel sends a
.Xr puffs 3
operation for the mounted file system,
.Nm
will translate it into a FUSE request, and will send it to the file system
daemon through
.Pa /dev/fuse .
The FUSE reply will be converted back into a
.Xr puffs 3
reply and will be relayed to the kernel.
.Pp
FUSE file system daemons must be modified so that they request
.Nm
to perform the
.Xr mount 2
system call instead of doing it on their own.
This is done by replacing
.Xr mount 2
and the
.Xr open 2
calls for
.Pa /dev/fuse
with
.Fn perfuse_mount
and
.Fn perfuse_open ,
respectively, in their sources.
.Xr libperfuse 3
must be used at link time.
Most FUSE file system daemons use
.Nm libfuse
and will work unmodified, provided the modification is done in
.Nm libfuse
itself.
.Pp
The following options are available:
.Bl -tag -width XdXtypesXX
.It Fl d Ar types
Print additional debug information.
.Ar types
is a comma-separated list of information types to print:
.Bl -tag -width indent
.It Ar puffs
Display PUFFS requests and replies.
.It Ar fuse
Display FUSE requests and replies.
.It Ar dump
Dump content of FUSE frames.
.It Ar fh
Display file handle activity.
.It Ar reclaim
Display reclaim activity.
.It Ar readdir
Display readdir activity.
.It Ar requeue
Display requeue activity.
.It Ar sync
Display dirty flags and sync operations.
.El
.It Fl f
Do not fork, but stay in the foreground.
.It Fl i Ar fd
Do not open
.Pa /dev/fuse
but use the socket available from the file descriptor
.Ar fd .
This is used when
.Nm
is started from
.Xr libperfuse 3 .
.It Fl s
Enable debug output only when receiving
.Li SIGINFO .
.El
.Sh ENVIRONMENT
See
.Xr libperfuse 3
for environment variables affecting
.Nm
behavior.
.Sh SIGNALS
.Bl -tag -width indent
.It Dv SIGINFO
If the
.Fl s
flag was used, toggle debug output.
Do nothing otherwise.
.It Dv SIGUSR1
Toggle FUSE operation dump on and off.
When toggling off, the trace
is is stored in
.Pa /var/run/perfuse-xxx.trace
(xxx is the filesystem mount point).
.El
.Sh ERRORS
The program logs to the syslog daemon as facility
.Dq daemon .
For detailed debugging use the
.Fl d
(debug) option.
.Sh SEE ALSO
.Xr mount 2 ,
.Xr perfuse_mount 3 ,
.Xr puffs 4
.Sh AUTHORS
The program was written by
.An Emmanuel Dreyfus
.Aq manu@NetBSD.org .
.Sh BUGS
When
.Nm
runs in the foreground (using the
.Fl f
flag), some processes using the FUSE file system will
sometimes hang on
.Sq uvn_fp2 .