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RUMP_SP(7)          NetBSD Miscellaneous Information Manual         RUMP_SP(7)


NAME

     rump_sp -- rump remote system call support


DESCRIPTION

     The rump_sp facility allows clients to attach to a rump kernel server
     over a socket and perform system calls.  While making a local rump system
     call is faster than calling the host kernel, a remote system call over a
     socket is slower.  This facility is therefore meant mostly for operations
     which are not performance critical, such as configuration of a rump ker-
     nel server.

   Clients
     The NetBSD base system comes with multiple preinstalled clients which can
     be used to configure a rump kernel and request diagnostic information.
     These clients run as hybrids partially in the host system and partially
     against the rump kernel.  For example, network-related clients will typi-
     cally avoid making any file system related system calls against the rump
     kernel, since it is not guaranteed that a rump network server has file
     system support.  Another example is DNS: since a rump server very rarely
     has a DNS service configured, host networking is used to do DNS lookups.

     Some examples of clients include rump.ifconfig which configures inter-
     faces, rump.sysctl which is used to access the sysctl(7) namespace and
     rump.traceroute which is used to display a network trace starting from
     the rump kernel.

     Also, almost any unmodified dynamically linked application (for example
     telnet(1) or ls(1)) can be used as a rump kernel client with the help of
     system call hijacking.  See rumphijack(3) for more information.

   Connecting to the server
     A remote rump server is specified using an URL.  Currently two types of
     URLs are supported: TCP and local domain sockets.  The TCP URL is of the
     format tcp://ip.address:port/ and the local domain URL is unix://path.
     The latter can accept relative or absolute paths.  Note that absolute
     paths require three leading slashes.

     To preserve the standard usage of the rump clients' counterparts the
     environment variable RUMP_SERVER is used to specify the server URL.  To
     keep track of which rump kernel the current shell is using, modifying the
     shell prompt is recommended -- this is analoguous to the visual clue you
     have when you login from one machine to another.

   Client credentials and access control
     The current scheme gives all connecting clients root credentials.  It is
     recommended to take precautions which prevent unauthorized access.  For a
     unix domain socket it is enough to prevent access to the socket using
     file system permissions.  For TCP/IP sockets the only available means is
     to prevent network access to the socket with the use of firewalls.  More
     fine-grained access control based on cryptographic credentials may be
     implemented at a future date.


EXAMPLES

     Get a list of file systems supported by a rump kernel server (in case
     that particular server does not support file systems, an error will be
     returned):

           $ env RUMP_SERVER=unix://sock rump.sysctl vfs.generic.fstypes


SEE ALSO

     rump_server(1), rump(3), rumpclient(3), rumphijack(3)


HISTORY

     rump_sp first appeared in NetBSD 6.0.

NetBSD 6.1.5                   February 7, 2011                   NetBSD 6.1.5