umview

VIEW-OS(1)                  General Commands Manual                 VIEW-OS(1)



NAME
       umview - User Mode implementation of View-OS

SYNOPSIS
       umview [ options ] prog

DESCRIPTION
       The main goal of the View-OS project is to give each process its own
       view of the system resources.  For example, each process can mount
       filesystems or hide some file or directories. It is also possible to
       assign virtual network interfaces, IP addresses or define virtual
       devices for each process (or for hierarchies of processes).
       umview is the user mode implementation of View-OS concepts.  It is a
       modular partial virtual machine.  umview before loading any module is
       completely transparent, a process behaves inside umview as it would
       have behaved outside.  Each module can customize specific entities:
       there are modules to mount filesystems at user-level (umfuse) , to
       define virtual network interfaces (lwipv6) , to define virtual devices
       (umdev) , to provide interpreters for executables, e.g. to support
       executables for foreign architectures (umbinfmt) , to hide, move,
       overlay parts of the file system (viewfs).
       These are some examples of modules provided by the View-OS team.
       umview aims to provide a general interface to customize the system call
       semantics of process under specified conditions. So more modules will
       be added both by the View-OS team and by third parties.

OPTIONS
       -V name
       --viewname name
           set the name of the view. The view can be read and set using vuname
           or viewname commands.
       -p module [ , module_options ]
       --preload module [ , module_options ]
           preload modules.  Modules will be loaded as shared libraries thus
           all the rules to load libraries apply. Modules must be loaded from
           a directory within the ld.so search path or should be specified by
           their pathnames.  If necessary configure the LD_LIBRARY_PATH
           environment variable appropriately.  module_options are module
           specific configuration options, thus the reader should refer to
           each service module manual for a complete description.  Modules can
           be loaded at run time using the um_add_service command.
       -s
       --secure
           set kmview in human mode, i.e. force the check of capabilities and
           permissions. uid is 0 at startup, in this way it is possible to
           load modules and mount services. When a process sets its uid as an
           unprivileged user (via setuid(2) or viewsu(1)), capability and
           permissions are enforced.
       -f rcfile
       --rc rcfile
           Use rcfile as the initialization file for kmview.  kmview always
           executes /etc/viewosrc if exists, then kmview executes the
           initialization file set by this option or ~/.viewosrc.
       -x
       --nonesting
           umview is able to provide module nesting, i.e. a module can provide
           services on the basis of virtual services provided by another
           module or even by the module itself. For example it is possible to
           mount a file system image which is stored in an already virtually
           mounted filesystem.  This feature requires the pure_libc library.
           The -x or --nonesting option disables the nesting feature.
       -n
       --nokernelpatch
           umview is able to use some specific kernel extensions (when
           present) to increase its performance. The source distribution of
           umview include the kernel patches for the latest kernels.  The
           kernel extensions are enabled by default when available.  This
           option disables the kernel extensions.
       --nokmulti
           This option disables the PTRACE_MULTI kernel extension.
       --noksysvm
           This option disables the PTRACE_SYSVM kernel extension.
       --nokviewos
           This option disables the PTRACE_SYSVIEWOS kernel extension (already
           experimental, not yet released).
       -o file
       --output file
           This option diverts the debugging output to the file specified, it
           is useful when umview has been compiled with debugging extensions.
       -v
       --version
           Print the version and exit.
       -h
       --help
           Print a short help message and exit.
SEE ALSO
       um_add_service(1) um_del_service(1) um_ls_service(1) um_mov_service(1)
       umfuse(1viewos) lwipv6(1viewos) umdev(1viewos) umbinfmt(1viewos)
       viewfs(1viewos) vuname(1viewos) viewname(1viewos)
AUTHORS
       View-OS is a project of the Computer Science Department, University of
       Bologna. Project Leader: Renzo Davoli. Development Team: P. Angelelli,
       A.  Bacchelli, M. Belletti, P. Beverini, D. Billi, A. Forni, L.
       Gardenghi, A. Gasparini, D. Lacamera, C. Martellini, A. Seraghiti
       <http://www.sourceforge.net/projects/view-os>

       Howto's and further information can be found on the project wiki
       <wiki.virtualsquare.org>.





VIEW-OS: a process with a view   June 10, 2006                      VIEW-OS(1)