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RUMP_ETFS(3)            NetBSD Library Functions Manual           RUMP_ETFS(3)


NAME

     rump_etfs -- rump kernel host file system interface


LIBRARY

     rump kernel (librump, -lrump)


SYNOPSIS

     #include <rump/rump.h>

     int
     rump_pub_etfs_register(const char *key, const char *hostpath,
         enum rump_etfs_type ftype);

     int
     rump_pub_etfs_register_withsize(const char *key, const char *hostpath,
         enum rump_etfs_type ftype, uint64_t begin, uint64_t size);

     void
     rump_boot_etfs_register(struct rump_boot_etfs *eb);

     int
     rump_pub_etfs_remove(const char *key);


DESCRIPTION

     The rump ExtraTerrestrial File System (rump_etfs) is used to provide
     access to the host file system namespace within a rump kernel.

     The operation is based on registered key values which each map to a
     hostpath.  A key must be an absolute path (i.e. begin with ``/'').  Mul-
     tiple leading slashes are collapsed to one (i.e.  ``/key'' is the same as
     ``//key'').  The rest of the path, including slashes, is compared verba-
     tim (i.e.  ``/key/path'' does not match ``/key//path'').

     The hostpath is interpreted in host system context for the current work-
     ing directory and can be either absolute or relative.

     The key is accessible from all rump kernel clients, both local and
     remote.  Note: the keys are not visible via readdir, so you will not see
     them in directory listings.

     The ftype parameter specifies how the etfs file will be presented and
     does not have to match the host type, although some limitations apply.
     Possible values are:

     RUMP_ETFS_REG             regular file.

     RUMP_ETFS_BLK             block device.  This is often used when mapping
                               file system images.

     RUMP_ETFS_CHR             character device.

     RUMP_ETFS_DIR             directory.  This option is valid only when
                               hostpath is a directory.  The immediate chil-
                               dren of the host directory will be accessible
                               inside a rump kernel.

     RUMP_ETFS_DIR_SUBDIRS     directory.  This option is valid only when
                               hostpath is a directory.  This option recur-
                               sively applies to all subdirectories, and
                               allows a rump kernel to access an entire direc-
                               tory tree.

     The interfaces are:

     rump_pub_etfs_register(key, hostpath, ftype)
           Map key to a file of type ftype with the contents of hostpath.

     rump_pub_etfs_register_withsize(key, hostpath, ftype, begin, size)
           Like the above, but map only [begin, begin+size] from hostpath.
           This is useful when mapping disk images where only one partition is
           relevant to the application.  If size is given the special value
           RUMP_ETFS_SIZE_ENDOFF, the underlying file is mapped from begin to
           the end of the file.

     rump_boot_etfs_register(eb)
           Unlike the above interfaces, rump_boot_etfs_register() can and must
           be called before rump_init().  It causes an etfs key to be avail-
           able immediately when the root file system is mounted as part of
           rump_init().  The intended use is for example for firmware images
           to be available immediately when device driver autoconfiguration is
           run as part of rump_init().

           To use rump_boot_etfs_register(), the client fills out eb.  The
           layout of eb is as follows:

           struct rump_boot_etfs {
                   /* client initializes */
                   const char *eb_key;
                   const char *eb_hostpath;
                   enum rump_etfs_type eb_type;
                   uint64_t eb_begin;
                   uint64_t eb_size;

                   /* rump kernel initializes */
                   struct rump_boot_etfs *_eb_next;
                   int eb_status;
           };

           All of the client fields must be initialized before the call.  See
           rump_pub_etfs_register_withsize() for descriptions of the fields.
           After the function has been called, the client may not touch the
           structure memory or the pathname pointers.  After rump_init()
           returns, the client may check the status of the registration from
           eb_status and free the structure.  A value of -1 designates that
           the etfs registration was not performed, 0 designates success and a
           value larger than 0 designates an errno.  The client must serialize
           calls to rump_boot_etfs_register().

     rump_pub_etfs_remove(key)
           Remove etfs mapping for key.  This routine may be called only if
           the file related to the mapping is not in use.


RETURN VALUES

     rump_etfs routines return 0 on success or an errno indicating the reason
     for failure.


EXAMPLES

     Map a host image file to a mountable /dev/harddisk path using window off-
     sets from the disklabel.

           rump_pub_etfs_register_withsize("/dev/harddisk", "disk.img",
               RUMP_ETFS_BLK,
               pp->p_offset << DEV_BSHIFT, pp->p_size << DEV_BSHIFT);

     Make the host kernel module directory hierarchy available within the rump
     kernel.

           rump_pub_etfs_register("/stand/i386/5.99.41",
               "/stand/i386/5.99.41", RUMP_ETFS_DIR_SUBDIRS);


SEE ALSO

     rump(3)


HISTORY

     rump_etfs first appeared in NetBSD 6.0.

NetBSD 10.1                    October 27, 2014                    NetBSD 10.1