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Dd October 27, 2014
Dt RUMP_ETFS 3
Os
Sh NAME
Nm rump_etfs
Nd rump kernel host file system interface
Sh LIBRARY
rump kernel (librump, \-lrump)
Sh SYNOPSIS
In rump/rump.h
Ft int
Fo rump_pub_etfs_register
Fa "const char *key" "const char *hostpath" "enum rump_etfs_type ftype"
Fc
Ft int
Fo rump_pub_etfs_register_withsize
Fa "const char *key" "const char *hostpath" "enum rump_etfs_type ftype"
Fa "uint64_t begin" "uint64_t size"
Fc
Ft void
Fn rump_boot_etfs_register "struct rump_boot_etfs *eb"
Ft int
Fn rump_pub_etfs_remove "const char *key"
Sh DESCRIPTION
The rump ExtraTerrestrial File System
Nm ( )
is used to provide access to the host file system namespace
within a rump kernel.
Pp
The operation is based on registered
Fa key
values which each map to a
Fa hostpath .
A key must be an absolute path (i.e. begin with
Dq / ) .
Multiple leading slashes are collapsed to one (i.e.
Dq /key
is the same as
Dq //key ) .
The rest of the path, including slashes, is compared verbatim (i.e.
Dq /key/path
does not match
Dq /key//path ) .
Pp
The
Fa hostpath
is interpreted in host system context for the current working directory
and can be either absolute or relative.
Pp
The
Fa 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.
Pp
The
Fa 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:
Bl -tag -width RUMP_ETFS_DIR_SUBDIRSXXX
It Dv RUMP_ETFS_REG
regular file.
It Dv RUMP_ETFS_BLK
block device.
This is often used when mapping file system images.
It Dv RUMP_ETFS_CHR
character device.
It Dv RUMP_ETFS_DIR
directory.
This option is valid only when
Fa hostpath
is a directory.
The immediate children of the host directory will be accessible
inside a rump kernel.
It Dv RUMP_ETFS_DIR_SUBDIRS
directory.
This option is valid only when
Fa hostpath
is a directory.
This option recursively applies to all subdirectories, and allows
a rump kernel to access an entire directory tree.
El
Pp
The interfaces are:
Bl -tag -width xxxx
It Fn rump_pub_etfs_register "key" "hostpath" "ftype"
Map
Fa key
to a file of type
Fa ftype
with the contents of
Fa hostpath .
It Fn rump_pub_etfs_register_withsize "key" "hostpath" "ftype" "begin" "size"
Like the above, but map only
Fa [ begin , begin+size ]
from
Fa hostpath .
This is useful when mapping disk images where only one partition is
relevant to the application.
If
Ar size
is given the special value
Dv RUMP_ETFS_SIZE_ENDOFF ,
the underlying file is mapped from
Ar begin
to the end of the file.
It Fn rump_boot_etfs_register "eb"
Unlike the above interfaces,
Fn rump_boot_etfs_register
can and must be called before
Fn rump_init .
It causes an etfs key to be available immediately when the root file
system is mounted as part of
Fn rump_init .
The intended use is for example for firmware images to be available
immediately when device driver autoconfiguration is run as part of
Fn rump_init .
Pp
To use
Fn rump_boot_etfs_register ,
the client fills out
Fa eb .
The layout of
Fa eb
is as follows:
Bd -literal
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;
};
Ed
Pp
All of the client fields must be initialized before the call.
See
Fn 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
Fn rump_init
returns, the client may check the status of the registration from
Fa 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
Fn rump_boot_etfs_register .
It Fn rump_pub_etfs_remove "key"
Remove etfs mapping for
Fa key .
This routine may be called only if the file related to the mapping
is not in use.
El
Sh RETURN VALUES
Nm
routines return 0 on success or an errno indicating the reason for failure.
Sh EXAMPLES
Map a host image file to a mountable
Pa /dev/harddisk
path using window offsets from the disklabel.
Bd -literal -offset indent
rump_pub_etfs_register_withsize("/dev/harddisk", "disk.img",
   RUMP_ETFS_BLK,
   pp->p_offset << DEV_BSHIFT, pp->p_size << DEV_BSHIFT);
Ed
Pp
Make the host kernel module directory hierarchy available within the
rump kernel.
Bd -literal -offset indent
rump_pub_etfs_register("/stand/i386/5.99.41",
   "/stand/i386/5.99.41", RUMP_ETFS_DIR_SUBDIRS);
Ed
Sh SEE ALSO
Xr rump 3
Sh HISTORY
Nm
first appeared in
Nx 6.0 .

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