mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-24 11:29:10 +00:00
389 lines
10 KiB
Groff
389 lines
10 KiB
Groff
.\" $FreeBSD$
|
|
.\"
|
|
.\" Copyright (c) 2010-2013 Hans Petter Selasky
|
|
.\"
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.Dd June 6, 2014
|
|
.Dt CUSE 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm libcuse
|
|
.Nd "Userland character device library"
|
|
.Sh LIBRARY
|
|
.Lb libcuse
|
|
.Sh SYNOPSIS
|
|
To load the required kernel module at boot time, place the following line in
|
|
.Xr loader.conf 5 :
|
|
.Bd -literal -offset indent
|
|
cuse_load="YES"
|
|
.Ed
|
|
.Pp
|
|
.In cuse.h
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
library contains functions to create a character device in userspace.
|
|
The
|
|
.Nm
|
|
library is thread safe.
|
|
.Sh LIBRARY INITIALISATION / DEINITIALISATION
|
|
.Ft "int"
|
|
.Fn "cuse_init" "void"
|
|
This function initialises
|
|
.Nm .
|
|
Must be called at the beginning of the program.
|
|
This function returns 0 on success or a negative value on failure.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
If the cuse kernel module is not loaded,
|
|
.Dv CUSE_ERR_NOT_LOADED
|
|
is returned.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_uninit" "void"
|
|
Deinitialise
|
|
.Nm .
|
|
Can be called at the end of the application.
|
|
This function returns 0 on success or a negative value on failure.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
.Sh UNIT MANAGEMENT
|
|
.Ft "int"
|
|
.Fn "cuse_alloc_unit_number" "int *"
|
|
This function stores a uniq system unit number at the pointed
|
|
integer loation.
|
|
This function returns 0 on success or a negative value on failure.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_alloc_unit_number_by_id" "int *" "int id"
|
|
This function stores a unique system unit number at the pointed
|
|
integer loation.
|
|
The returned unit number is uniq within the given ID.
|
|
Valid ID values are defined by the cuse include file.
|
|
See the
|
|
.Fn CUSE_ID_XXX
|
|
macros for more information.
|
|
This function returns 0 on success or a negative value on failure.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_free_unit_number" "int"
|
|
This function frees the given allocated system unit number.
|
|
This function returns 0 on success or a negative value on failure.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_free_unit_number_by_id" "int unit" "int id"
|
|
This function frees the given allocated system unit number belonging
|
|
to the given ID.
|
|
If both the unit and id argument is -1, all allocated units will be freed.
|
|
This function returns 0 on success or a negative value on failure.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
.Sh LIBRARY USAGE
|
|
.Ft "void *"
|
|
.Fn "cuse_vmalloc" "int size"
|
|
This function allocates
|
|
.Ar size
|
|
bytes of memory.
|
|
Only memory allocated by this function can be memory
|
|
mapped by
|
|
.Xr mmap 2 .
|
|
This function returns a valid data pointer on success or
|
|
.Dv NULL
|
|
on failure.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_is_vmalloc_addr" "void *"
|
|
This function returns non-zero if the passed pointer points to a valid
|
|
and non-freed allocation, as returned by
|
|
.Fn cuse_vmalloc .
|
|
Else this function returns zero.
|
|
.Pp
|
|
.Ft "void"
|
|
.Fn "cuse_vmfree" "void *"
|
|
This function frees memory allocated by
|
|
.Fn cuse_vmalloc .
|
|
Note that the
|
|
cuse library will internally not free the memory until the
|
|
.Fn cuse_uninit
|
|
function is called and that the number of unique
|
|
allocations is limited.
|
|
.Pp
|
|
.Ft "unsigned long"
|
|
.Fn "cuse_vmoffset" "void *"
|
|
This function returns the mmap offset that the client must use to
|
|
access the allocated memory.
|
|
.Pp
|
|
.Ft "struct cuse_dev *"
|
|
.Fn "cuse_dev_create" "const struct cuse_methods *mtod" "void *priv0" "void *priv1" "uid_t" "gid_t" "int permission" "const char *fmt" "..."
|
|
This function creates a new character device according to the given
|
|
parameters.
|
|
This function returns a valid cuse_dev structure pointer
|
|
on success or
|
|
.Dv NULL
|
|
on failure.
|
|
The device name can only contain a-z,
|
|
A-Z, 0-9, dot, / and underscore characters.
|
|
.Pp
|
|
.Ft "void"
|
|
.Fn "cuse_dev_destroy" "struct cuse_dev *"
|
|
This functions destroys a previously created character device.
|
|
.Pp
|
|
.Ft "void *"
|
|
.Fn "cuse_dev_get_priv0" "struct cuse_dev *" ,
|
|
.Ft "void *"
|
|
.Fn "cuse_dev_get_priv1" "struct cuse_dev *" ,
|
|
.Ft "void"
|
|
.Fn "cuse_dev_set_priv0" "struct cuse_dev *" "void *" ,
|
|
.Ft "void"
|
|
.Fn "cuse_dev_set_priv1" "struct cuse_dev *" "void *"
|
|
These functions are used to set and get the private data of the given
|
|
cuse device.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_wait_and_process" "void"
|
|
This function will block and do event processing.
|
|
If parallel I/O is
|
|
required multiple threads must be created looping on this
|
|
function.
|
|
This function returns 0 on success or a negative value on failure.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
.Pp
|
|
.Ft "void *"
|
|
.Fn "cuse_dev_get_per_file_handle" "struct cuse_dev *" ,
|
|
.Ft "void"
|
|
.Fn "cuse_dev_set_per_file_handle" "struct cuse_dev *" "void *"
|
|
These functions are used to set and get the per-file-open specific handle
|
|
and should only be used inside the cuse file operation callbacks.
|
|
.Pp
|
|
.Ft "void"
|
|
.Fn "cuse_set_local" "int"
|
|
This function instructs
|
|
.Fn cuse_copy_out
|
|
and
|
|
.Fn cuse_copy_in
|
|
that the
|
|
user pointer is local, if the argument passed to it is non-zero.
|
|
Else the user pointer is assumed to be at the peer application.
|
|
This function should only be used inside the cuse file operation callbacks.
|
|
The value is reset to zero when the given file operation returns, and
|
|
does not affect any other file operation callbacks.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_get_local" "void"
|
|
Returns the current local state.
|
|
See
|
|
.Fn cuse_set_local .
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_copy_out" "const void *src" "void *peer_dst" "int len" ,
|
|
.Ft "int"
|
|
.Fn "cuse_copy_in" "const void *peer_src" "void *dst" "int len"
|
|
These functions are used to transfer data between the local
|
|
application and the peer application.
|
|
These functions must be used
|
|
when operating on the data pointers passed to the
|
|
.Fn cm_read ,
|
|
.Fn cm_write ,
|
|
and
|
|
.Fn cm_ioctl
|
|
callback functions.
|
|
These functions return 0 on success or a negative value on failure.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_got_peer_signal" "void"
|
|
This function is used to check if a signal has been delivered to the
|
|
peer application and should only be used inside the cuse file
|
|
operation callbacks.
|
|
This function returns 0 if a signal has been
|
|
delivered to the caller.
|
|
Else it returns a negative value.
|
|
See
|
|
.Dv CUSE_ERR_XXX
|
|
for known error codes.
|
|
.Pp
|
|
.Ft "struct cuse_dev *"
|
|
.Fn "cuse_dev_get_current" "int *pcmd"
|
|
This function is used to get the current cuse device pointer and the
|
|
currently executing command, by
|
|
.Dv CUSE_CMD_XXX
|
|
value.
|
|
The
|
|
.Ar pcmd
|
|
argument
|
|
is allowed to be
|
|
.Dv NULL .
|
|
This function should only be used inside the
|
|
cuse file operation callbacks.
|
|
On success a valid cuse device pointer
|
|
is returned.
|
|
On failure
|
|
.Dv NULL
|
|
is returned.
|
|
.Pp
|
|
.Ft "void"
|
|
.Fn "cuse_poll_wakeup" "void"
|
|
This function will wake up any file pollers.
|
|
.Sh LIBRARY LIMITATIONS
|
|
Transfer lengths for
|
|
.Fn read ,
|
|
.Fn write ,
|
|
.Fn cuse_copy_in ,
|
|
and
|
|
.Fn cuse_copy_out
|
|
should not exceed what can fit into a 32-bit signed integer and is
|
|
defined by the
|
|
.Fn CUSE_LENGTH_MAX
|
|
macro.
|
|
Transfer lengths for ioctls should not exceed what is defined by the
|
|
.Fn CUSE_BUFFER_MAX
|
|
macro.
|
|
.Sh LIBRARY CALLBACK METHODS
|
|
In general fflags are defined by
|
|
.Dv CUSE_FFLAG_XXX
|
|
and errors are defined by
|
|
.Dv CUSE_ERR_XXX .
|
|
.Bd -literal -offset indent
|
|
enum {
|
|
CUSE_ERR_NONE
|
|
CUSE_ERR_BUSY
|
|
CUSE_ERR_WOULDBLOCK
|
|
CUSE_ERR_INVALID
|
|
CUSE_ERR_NO_MEMORY
|
|
CUSE_ERR_FAULT
|
|
CUSE_ERR_SIGNAL
|
|
CUSE_ERR_OTHER
|
|
CUSE_ERR_NOT_LOADED
|
|
|
|
CUSE_POLL_NONE
|
|
CUSE_POLL_READ
|
|
CUSE_POLL_WRITE
|
|
CUSE_POLL_ERROR
|
|
|
|
CUSE_FFLAG_NONE
|
|
CUSE_FFLAG_READ
|
|
CUSE_FFLAG_WRITE
|
|
CUSE_FFLAG_NONBLOCK
|
|
|
|
CUSE_CMD_NONE
|
|
CUSE_CMD_OPEN
|
|
CUSE_CMD_CLOSE
|
|
CUSE_CMD_READ
|
|
CUSE_CMD_WRITE
|
|
CUSE_CMD_IOCTL
|
|
CUSE_CMD_POLL
|
|
CUSE_CMD_SIGNAL
|
|
CUSE_CMD_SYNC
|
|
CUSE_CMD_MAX
|
|
};
|
|
.Ed
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_open_t" "struct cuse_dev *" "int fflags"
|
|
This function returns a
|
|
.Dv CUSE_ERR_XXX
|
|
value.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_close_t" "struct cuse_dev *" "int fflags"
|
|
This function returns a
|
|
.Dv CUSE_ERR_XXX
|
|
value.
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_read_t" "struct cuse_dev *" "int fflags" "void *peer_ptr" "int len"
|
|
This function returns a
|
|
.Dv CUSE_ERR_XXX
|
|
value in case of failure or the
|
|
actually transferred length in case of success.
|
|
.Fn cuse_copy_in
|
|
and
|
|
.Fn cuse_copy_out
|
|
must be used to transfer data to and from the
|
|
.Ar peer_ptr .
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_write_t" "struct cuse_dev *" "int fflags" "const void *peer_ptr" "int len"
|
|
This function returns a
|
|
.Dv CUSE_ERR_XXX
|
|
value in case of failure or the
|
|
actually transferred length in case of success.
|
|
.Fn cuse_copy_in
|
|
and
|
|
.Fn cuse_copy_out
|
|
must be used to transfer data to and from the
|
|
.Ar peer_ptr .
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_ioctl_t" "struct cuse_dev *" "int fflags" "unsigned long cmd" "void *peer_data"
|
|
This function returns a
|
|
.Dv CUSE_ERR_XXX
|
|
value in case of failure or zero
|
|
in case of success.
|
|
.Fn cuse_copy_in
|
|
and
|
|
.Fn cuse_copy_out
|
|
must be used to
|
|
transfer data to and from the
|
|
.Ar peer_data .
|
|
.Pp
|
|
.Ft "int"
|
|
.Fn "cuse_poll_t" "struct cuse_dev *" "int fflags" "int events"
|
|
This function returns a mask of
|
|
.Dv CUSE_POLL_XXX
|
|
values in case of failure and success.
|
|
The events argument is also a mask of
|
|
.Dv CUSE_POLL_XXX
|
|
values.
|
|
.Bd -literal -offset indent
|
|
struct cuse_methods {
|
|
cuse_open_t *cm_open;
|
|
cuse_close_t *cm_close;
|
|
cuse_read_t *cm_read;
|
|
cuse_write_t *cm_write;
|
|
cuse_ioctl_t *cm_ioctl;
|
|
cuse_poll_t *cm_poll;
|
|
};
|
|
.Ed
|
|
.Sh HISTORY
|
|
.Nm
|
|
was written by Hans Petter Selasky.
|