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.Dd January 15, 2014
.Dt RUMP_SERVER 1
.Os
.Sh NAME
.Nm rump_server ,
.Nm rump_allserver
.Nd rump kernel server
.Sh SYNOPSIS
.Nm
.Op Fl sv
.Op Fl c Ar ncpu
.Op Fl d Ar drivespec
.Op Fl l Ar library
.Op Fl m Ar module
.Op Fl r Ar total_ram
.Ar url
.Sh DESCRIPTION
The
.Nm
utility is used to provide a rump kernel service.
Clients can use the system calls provided by
.Nm
via
.Ar url .
.Pp
The difference between
.Nm
and
.Nm rump_allserver
is that
.Nm
offers only a minimalistic set of features,
while
.Nm rump_allserver
provides all rump kernel components which were available when the
system was built.
At execution time it is possible to load components from the command
line as described in the options section.
.Bl -tag -width indent
.It Fl c Ar ncpu
Configure
.Ar ncpu
virtual CPUs on SMP-capable archs.
By default, the number of CPUs equals the number of CPUs on the
host.
.It Fl d Ar drivespec
The argument
.Ar drivespec
maps a host file in the rump kernel fs namespace.
The string
.Ar drivespec
must be of comma-separated
.Dq name=value
format and must contain the following tokens:
.Bl -tag -width hostpath1234
.It Ar key
Block device path in rump kernel namespace.
This must be specified according to the rules for a key in
.Xr rump_etfs 3 .
.It Ar hostpath
Host file used for storage.
If the file does not exist, it will be created.
.It Ar size
Size of the mapping.
Similar to
.Xr dd 1 ,
this argument accepts a suffix as the multiplier for the number.
The special value
.Dq host
indicates that the current size of
.Ar hostpath
will be used.
In this case it is assumed that
.Ar hostpath
exists and is a regular file.
.It OR
.It Ar disklabel
Use a disklabel partition identifier to specify the offset and size
of the mapping.
.Ar hostpath
must contain an existing and valid disklabel within the first 64k.
.El
.Pp
The following are optional:
.Bl -tag -width hostpath1234
.It Ar offset
Offset of the mapping.
The window into
.Ar hostpath
therefore is
.Fa [ offset , offset+size ] .
In case this parameter is not given, the default value 0 is used.
.It Ar type
The type of file that
.Ar key
is exposed as within the rump kernel.
The possibilities are
.Dq blk ,
.Dq chr ,
and
.Dq reg
for block device, character device and regular file, respectively.
The default is a block device.
.Pp
Note: the contents of block devices are cached in the rump kernel's
buffer cache.
To avoid cache incoherency, it is advisable not to access a file
through the host namespace while it is mapped as a block device in
a rump kernel.
.El
.Pp
In case
.Ar hostpath
does not exist, it will be created as a regular file with mode
0644 (plus any restrictions placed by umask).
In case
.Ar hostpath
is a regular file and is not large enough to accommodate the
specified size, it will be extended to the specified size.
.It Fl l Ar library
Call
.Fn dlopen
on library before initializing the rump kernel.
In case
.Ar library
provides a kernel module, it will appear as a builtin module in the
rump kernel.
Any rump kernel component present in
.Ar library
will also be initialized.
.Pp
The argument
.Ar library
can contain a full path or a filename, in which case the standard
dynamic library search path will be used.
By default, lazy resolution is used, and may result in a runtime
error due to missing components.
To test a configuration, run
.Nm
with
.Ev LD_BIND_NOW=1
(see examples).
.It Fl m Ar module
Load and link a kernel module after the rump kernel is initialized.
For this to work, the rump kernel must include the vfs faction,
since the module is loaded using kernel vfs code (see
.Sx EXAMPLES ) .
.It Fl r Ar total_ram
Sets the limit of kernel memory allocatable by the server to
.Ar total_ram
as opposed to the default which allows the server to allocate as much
memory as the host will give it.
This parameter is especially useful for VFS servers, since by
default the virtual file system will attempt to consume as much
memory as it can, and accessing large files can cause an excessive
amount of memory to be used as file system cache.
.It Fl s
Do not detach from the terminal.
By default,
.Nm
detaches from the terminal once the service is running on
.Ar url .
.It Fl v
Set bootverbose.
.El
.Pp
After use,
.Nm
can be made to exit using
.Xr rump.halt 1 .
.Sh EXAMPLES
Start a server and load the tmpfs file system module, and halt the
server immediately afterwards:
.Bd -literal -offset indent
$ rump_server -lrumpvfs -m /modules/tmpfs.kmod unix://sock
$ env RUMP_SERVER=unix://sock rump.halt
.Ed
.Pp
Start a server with the one gigabyte host file
.Pa dk.img
mapped as the block device
.Pa /dev/dk
in the rump kernel.
.Bd -literal -offset indent
$ rump_allserver -d key=/dev/dk,hostpath=dk.img,size=1g unix://sock
.Ed
.Pp
Start a server which listens on INADDR_ANY port 3755
.Bd -literal -offset indent
$ rump_server tcp://0:3755/
.Ed
.Pp
Test that a configuration contains all of the necessary components:
.Bd -literal -offset indent
$ env LD_BIND_NOW=1 rump_server -lrumpvfs -lrumpfs_ffs unix://tsock
.Ed
.Pp
Start a FFS server with a 16MB kernel memory limit.
.Bd -literal -offset indent
$ rump_server -lrumpfs_ffs [...] -r 16m unix://ffs
.Ed
.Sh SEE ALSO
.Xr rump.halt 1 ,
.Xr dlopen 3 ,
.Xr rump 3 ,
.Xr rump_sp 7