xbps/bin/xbps-uchroot/xbps-uchroot.1

.Dd June 12, 2019
.Dt XBPS-UCHROOT 1
.Sh NAME
.Nm xbps-uchroot
.Nd XBPS utility to chroot and bind mount with Linux namespaces
.Sh SYNOPSIS
.Nm xbps-uchroot
.Op OPTIONS
.Ar CHROOTDIR
.Ar COMMAND
.Op ARGS
.Sh DESCRIPTION
The
.Nm
utility allows users to chroot and bind mount required pseudo-filesystems
(/dev, /proc and /sys) in the target
.Ar CHROOTDIR
to execute
.Ar COMMAND .
The
.Nm
utility uses by default Linux namespaces to isolate IPC, PIDs and mounts to
the calling process. If running in a OpenVZ container, these namespace features
are simply disabled.
.Sh OPTIONS
.Bl -tag -width -x
.It Fl b Ar src:dest
Bind mounts
.Ar src
into
.Ar CHROOTDIR/dest .
This option may be specified multiple times.
Please note that both
.Ar src
and
.Ar dest
must be absolute paths and must exist.
.It Fl O
Setups a temporary directory and then creates an overlay layer (via overlayfs)
with the lowerdir set to CHROOTDIR. Useful to create a temporary tree that does not
preserve changes in CHROOTDIR.
.It Fl o Ar opts
Arguments passed to the tmpfs mount, if the
.Fl O
and
.Fl t
options are specified.
This expects the same arguments that are accepted as options in tmpfs, as explained in
.Xr mount 1 .
.It Fl t
This makes the temporary directory to be mounted in tmpfs, so that everything is stored
in RAM. Note that this is only useful if used with the
.Fl O
option (overlayfs).
.El
.Sh SECURITY
The
.Nm
executable must be setgid to function properly and shall only be executable by a specific
group to avoid security issues (4750).
.Sh NOTES
The
.Nm
utility uses Linux specific features (namespaces) and it's not meant to be portable to
other Operating Systems. The following kernel options must be enabled:
.Pp
.Bl -tag -width CONFIG_NAMESPACES -compact -offset indent
.It Sy CONFIG_NAMESPACES
.It Sy CONFIG_IPC_NS
.It Sy CONFIG_PID_NS
.It Sy CONFIG_UTS_NS
.It Sy CONFIG_OVERLAY_FS
.El
.Sh SEE ALSO
.Xr xbps-checkvers 1 ,
.Xr xbps-create 1 ,
.Xr xbps-dgraph 1 ,
.Xr xbps-digest 1 ,
.Xr xbps-fbulk 1 ,
.Xr xbps-fetch 1 ,
.Xr xbps-install 1 ,
.Xr xbps-pkgdb 1 ,
.Xr xbps-query 1 ,
.Xr xbps-reconfigure 1 ,
.Xr xbps-rindex 1 ,
.Xr xbps-uunshare 1 ,
.Xr xbps.d 5
.Sh AUTHORS
.An Juan Romero Pardines <xtraeme@gmail.com>
.Sh BUGS
Probably, but I try to make this not happen. Use it under your own
responsibility and enjoy your life.
.Pp
Report bugs at https://github.com/void-linux/xbps/issues