NetBSD-5.0.2/share/man/man9/vnfileops.9

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.Dd April 9, 2008
.Dt VNFILEOPS 9
.Os
.Sh NAME
.Nm vnfileops ,
.Nm vn_closefile ,
.Nm vn_fcntl ,
.Nm vn_ioctl ,
.Nm vn_read ,
.Nm vn_poll ,
.Nm vn_statfile ,
.Nm vn_write
.Nd vnode file descriptor operations
.Sh SYNOPSIS
.In sys/param.h
.In sys/file.h
.In sys/vnode.h
.Ft int
.Fn vn_closefile "file_t *fp"
.Ft int
.Fn vn_fcntl "file_t *fp" "u_int com" "void *data"
.Ft int
.Fn vn_ioctl "file_t *fp" "u_long com" "void *data"
.Ft int
.Fn vn_read "file_t *fp" "off_t *offset" "struct uio *uio" "kauth_cred_t cred" "int flags"
.Ft int
.Fn vn_poll "file_t *fp" "int events"
.Ft int
.Fn vn_statfile "file_t *fp" "struct stat *sb"
.Ft int
.Fn vn_write "file_t *fp" "off_t *offset" "struct uio *uio" "kauth_cred_t cred" "int flags"
.Sh DESCRIPTION
The functions described in this page are the vnode-specific file
descriptor operations.
They should only be accessed through the opaque function pointers
in the file entries (see
.Xr file 9 ) .
They are described here only for completeness.
.Sh FUNCTIONS
.Bl -tag -width compact
.It Fn vn_closefile "fp" "l"
Common code for a file table vnode close operation.
The file is described by
.Fa fp
and
.Fa l
is the calling lwp.
.Fn vn_closefile
simply calls
.Xr vn_close 9
with the appropriate arguments.
.It Fn vn_fcntl "fp" "com" "data" "l"
Common code for a file table vnode
.Xr fcntl 2
operation.
The file is specified by
.Fa fp .
The argument
.Fa l
is the calling lwp.
.Fn vn_fcntl
simply locks the vnode and invokes the vnode operation
.Xr VOP_FCNTL 9
with the command
.Fa com
and buffer
.Fa data .
The vnode is unlocked on return.
If the operation is successful zero is returned, otherwise an
appropriate error is returned.
.It Fn vn_ioctl "fp" "com" "data" "l"
Common code for a file table vnode ioctl operation.
The file is specified by
.Fa fp .
The argument
.Fa l
is the calling lwp
.Fn vn_ioctl
simply locks the vnode and invokes the vnode operation
.Xr VOP_IOCTL 9
with the command
.Fa com
and buffer
.Fa data .
The vnode is unlocked on return.
If the operation is successful zero is returned, otherwise an
appropriate error is returned.
.It Fn vn_read "fp" "offset" "uio" "cred" "flags"
Common code for a file table vnode read.
The argument
.Fa fp
is the file structure,  The argument
.Fa offset
is the offset into the file.
The argument
.Fa uio
is the uio structure describing the memory to read into.
The caller's credentials are specified in
.Fa cred .
The
.Fa flags
argument can define FOF_UPDATE_OFFSET to update the read position in
the file.
If the operation is successful zero is returned, otherwise an
appropriate error is returned.
.It Fn vn_poll "fp" "events" "l"
Common code for a file table vnode poll operation.
.Fn vn_poll
simply calls
.Xr VOP_POLL 9
with the events
.Fa events
and the calling lwp
.Fa l .
The function returns a bitmask of available events.
.It Fn vn_statfile "fp" "sb" "l"
Common code for a stat operation.
The file descriptor is specified by the argument
.Fa fp
and
.Fa sb
is the buffer to return the stat information.
The argument
.Fa l
is the calling lwp.
.Fn vn_statfile
basically calls the vnode operation
.Xr VOP_GETATTR 9
and transfer the contents of a vattr structure into a struct stat.
If the operation is successful zero is returned, otherwise an
appropriate error code is returned.
.It Fn vn_write "fp" "offset" "uio" "cred" "flags"
Common code for a file table vnode write.
The argument
.Fa fp
is the file structure,  The argument
.Fa offset
is the offset into the file.
The argument
.Fa uio
is the uio structure describing the memory to read from.
The caller's credentials are specified in
.Fa cred .
The
.Fa flags
argument can define FOF_UPDATE_OFFSET to update the read position in
the file.
If the operation is successful zero is returned, otherwise an
appropriate error is returned.
.El
.Sh CODE REFERENCES
This section describes places within the
.Nx
source tree where actual code implementing or using the vnode
framework can be found.
All pathnames are relative to
.Pa /usr/src .
.Pp
The high-level convenience functions are implemented within the file
.Pa sys/kern/vfs_vnops.c .
.Sh SEE ALSO
.Xr file 9 ,
.Xr intro 9 ,
.Xr vnode 9 ,
.Xr vnodeops 9 ,
.Xr vnsubr 9