.\"	$NetBSD: prop_copyin_ioctl.9,v 1.15 2017/03/07 19:10:07 njoly Exp $
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.\" by Jason R. Thorpe.
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.Dd January 29, 2017
.Dt PROP_COPYIN_IOCTL 9
.Os
.Sh NAME
.Nm prop_array_copyin ,
.Nm prop_array_copyin_size ,
.Nm prop_array_copyin_ioctl ,
.Nm prop_array_copyin_ioctl_size ,
.Nm prop_array_copyout ,
.Nm prop_array_copyout_ioctl ,
.Nm prop_dictionary_copyin ,
.Nm prop_dictionary_copyin_size ,
.Nm prop_dictionary_copyin_ioctl ,
.Nm prop_dictionary_copyin_ioctl_size ,
.Nm prop_dictionary_copyout ,
.Nm prop_dictionary_copyout_ioctl
.Nd Copy property lists to and from kernel space
.Sh SYNOPSIS
.In prop/proplib.h
.Ft int
.Fn prop_array_copyin "const struct plistref *pref" \
    "prop_array_t *arrayp"
.Ft int
.Fn prop_array_copyin_size "const struct plistref *pref" \
    "prop_array_t *arrayp" "size_t lim"
.Ft int
.Fn prop_array_copyin_ioctl "const struct plistref *pref" \
    "const u_long cmd" "prop_array_t *arrayp"
.Ft int
.Fn prop_array_copyin_ioctl_size "const struct plistref *pref" \
    "const u_long cmd" "prop_array_t *arrayp" "size_t lim"
.Ft int
.Fn prop_array_copyout "struct plistref *pref" \
    "prop_array_t array"
.Ft int
.Fn prop_array_copyout_ioctl "struct plistref *pref" \
    "const u_long cmd" "prop_array_t array"
.Ft int
.Fn prop_dictionary_copyin "const struct plistref *pref" \
    "prop_dictionary_t *dictp"
.Ft int
.Fn prop_dictionary_copyin_size "const struct plistref *pref" \
    "prop_dictionary_t *dictp" "size_t lim"
.Ft int
.Fn prop_dictionary_copyin_ioctl "const struct plistref *pref" \
    "const u_long cmd" "prop_dictionary_t *dictp"
.Ft int
.Fn prop_dictionary_copyin_ioctl_size "const struct plistref *pref" \
    "const u_long cmd" "prop_dictionary_t *dictp" "size_t lim"
.Ft int
.Fn prop_dictionary_copyout "struct plistref *pref" \
    "prop_dictionary_t dict"
.Ft int
.Fn prop_dictionary_copyout_ioctl "struct plistref *pref" \
    "const u_long cmd" "prop_dictionary_t dict"
.Sh DESCRIPTION
The
.Nm prop_array_copyin_ioctl ,
.Nm prop_array_copyin_ioctl_size ,
.Nm prop_array_copyout_ioctl ,
.Nm prop_dictionary_copyin_ioctl ,
.Nm prop_dictionary_copyin_ioctl_size ,
and
.Nm prop_dictionary_copyout_ioctl
functions implement the kernel side of a protocol for copying property lists
to and from the kernel using
.Xr ioctl 2 .
The functions
.Nm prop_array_copyin ,
.Nm prop_array_copyin_size ,
.Nm prop_array_copyout ,
.Nm prop_dictionary_copyin ,
.Nm prop_dictionary_copyin_size ,
and
.Nm prop_dictionary_copyout
implement the kernel side of a protocol for copying property lists to the
kernel as arguments of normal system calls.
.Pp
A kernel routine receiving or returning a property list will be passed a
pointer to a
.Vt struct plistref .
This structure encapsulates the reference to the property list in externalized
form.
.Pp
The functions
.Nm prop_array_copyin_size ,
.Nm prop_array_copyin_ioctl_size ,
.Nm prop_dictionary_copyin_size ,
and
.Nm prop_dictionary_copyin_ioctl_size
take an explicit limit argument
.Ar lim
while
.Nm prop_array_copyin ,
.Nm prop_array_copyin_ioctl ,
.Nm prop_dictionary_copyin ,
and
.Nm prop_dictionary_copyin_ioctl
have an implicit size limit of 128KB.
Attempts to transfer objects larger than the limit result in an
.Er E2BIG
return value.
.Sh RETURN VALUES
If successful, functions return zero.
Otherwise, an error number will be returned to indicate the error.
.Sh EXAMPLES
The following
.Pq simplified
example demonstrates using
.Fn prop_dictionary_copyin_ioctl
and
.Fn prop_dictionary_copyout_ioctl
in an ioctl routine:
.Bd -literal
extern prop_dictionary_t fooprops;

int
fooioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct lwp *l)
{
    prop_dictionary_t dict, odict;
    int error;

    switch (cmd) {
    case FOOSETPROPS: {
	const struct plistref *pref = (const struct plistref *) data;
	error = prop_dictionary_copyin_ioctl(pref, cmd, \*[Am]dict);
	if (error)
		return (error);
	odict = fooprops;
	fooprops = dict;
	prop_object_release(odict);
	break;
      }

    case FOOGETPROPS: {
	struct plistref *pref = (struct plistref *) data;
	error = prop_dictionary_copyout_ioctl(pref, cmd, fooprops);
	break;
      }

    default:
	return (EPASSTHROUGH);
    }
    return (error);
}
.Ed
.Pp
The following
.Pq simplified
example demonstrates using
.Fn prop_array_copyin
in a routine:
.Bd -literal
int
foocopyin(const struct plistref *pref))
{
    prop_array_t array;
    int error;

    error = prop_array_copyin(pref, \*[Am]array);
    if (error)
	    return (error);
    ...
}
.Ed
.Sh ERRORS
.Fn prop_array_copyin_ioctl
and
.Fn prop_dictionary_copyin_ioctl
will fail if:
.Bl -tag -width Er
.It Bq Er E2BIG
The object being copied is larger than an arbitrarily established limit
(currently set to 128Kbytes).
.It Bq Er EFAULT
Bad address
.It Bq Er EIO
Input/output error
.It Bq Er ENOMEM
Cannot allocate memory
.It Bq Er ENOTSUP
Not supported
.El
.Pp
.Fn prop_array_copyout_ioctl
and
.Fn prop_dictionary_copyout_ioctl
will fail if:
.Bl -tag -width Er
.It Bq Er EFAULT
Bad address
.It Bq Er ENOMEM
Cannot allocate memory
.It Bq Er ENOTSUP
Not supported
.El
.Sh SEE ALSO
.Xr prop_array 3 ,
.Xr prop_dictionary 3 ,
.Xr prop_send_ioctl 3 ,
.Xr prop_send_syscall 3 ,
.Xr proplib 3
.Sh HISTORY
The
.Nm proplib
property container object library first appeared in
.Nx 4.0 .