NetBSD/share/man/man9/vnfileops.9

.\"     $NetBSD: vnfileops.9,v 1.2 2002/10/14 13:43:36 wiz Exp $
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.Dd October 14, 2002
.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
.Fd #include \*[Lt]sys/param.h\*[Gt]
.Fd #include \*[Lt]sys/file.h\*[Gt]
.Fd #include \*[Lt]sys/vnode.h\*[Gt]
.Ft int
.Fn vn_closefile "struct file *fp" "struct proc *p"
.Ft int
.Fn vn_fcntl "struct file *fp" "u_int com" "caddr_t data" "struct proc *p"
.Ft int
.Fn vn_ioctl "struct file *fp" "u_long com" "caddr_t data" "struct proc *p"
.Ft int
.Fn vn_read "struct file *fp" "off_t *offset" "struct uio *uio" "struct ucred *cred" "int flags"
.Ft int
.Fn vn_poll "struct file *fp" "int events" "struct proc *p"
.Ft int
.Fn vn_statfile "struct file *fp" "struct stat *sb" "struct proc *p"
.Ft int
.Fn vn_write "struct file *fp" "off_t *offset" "struct uio *uio" "struct ucred *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 descriptor entries.
They are described here only for completeness.
.Sh FUNCTIONS
.Bl -tag -width compact
.It Fn vn_closefile "fp" "p"
Common code for a file table vnode close operation.
The file is described by
.Fa fp
and
.Fa p
is the calling process.
.Fn vn_closefile
simply calls
.Fn vn_close
with the appropriate arguments.
.It Fn vn_fcntl "fp" "com" "data" "p"
Common code for a file table vnode
.Xr fcntl 2
operation.
The file is specified by
.Fa fp .
The argument
.Fa p
is the calling process.
.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" "p"
Common code for a file table vnode ioctl operation.
The file is specified by
.Fa fp .
The argument
.Fa p
is the calling process.
.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" "p"
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 process
.Fa p .
If the operation is success zero is returned, otherwise an appropriate
error code is returned.
.It Fn vn_statfile "fp" "sb" "p"
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 p
is the calling process.
.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 utilising 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 intro 9 ,
.\" file 9 ,
.Xr vnode 9 ,
.Xr vnodeops 9