openprom - OPENPROM interface
The file /dev/openprom is an interface to the UltraSPARC
interface is highly stylized; ioctls are used for all operations. These
ioctls refer to ``nodes'', which are simply ``magic'' integer values describing
data areas. Occasionally the number 0 may be used
instead, as described below.
The calls that take and/or return a node use a pointer to an
for this purpose; others use a pointer to a struct opiocdesc
which contains a node and two counted strings. The first
string is comprised
of the fields op_namelen (an int) and op_name (a char
the name of a field. The second string is comprised of the
op_buflen and op_buf, used analogously. These two counted
in a ``value-result'' fashion. At entry to the ioctl, the
counts are expected
to reflect the buffer size; on return, the counts are
reflect the buffer contents.
The following ioctls are supported:
OPIOCGETOPTNODE Takes nothing, and fills in the options
OPIOCGETNEXT Takes a node number and returns the number
of the following
node. The node following the last
node is number
0; the node following number 0 is the first
OPIOCGETCHILD Takes a node number and returns the number
of the first
``child'' of that node. This child may
these can be discovered by using OPIOCGETNEXT.
OPIOCGET Fills in the value of the named property
for the given
node. If no such property is associated
with that node,
the value length is set to -1. If the
exists but has no value, the value length
is set to 0.
OPIOCSET Writes the given value under the given
name. The OPENPROM
may refuse this operation; in this
case EINVAL is
OPIOCNEXTPROP Finds the property whose name follows the
given name in
OPENPROM internal order. The resulting
name is returned
in the value field. If the named property
is the last,
the ``next'' name is the empty string. As
OPIOCGETNEXT, the next name after the empty
the first name.
The following may result in rejection of an operation:
[EINVAL] The given node number is not zero and does
to any valid node, or is zero where zero is
[EBADF] The requested operation requires permissions
at the call to open().
[ENAMETOOLONG] The given name or value field exceeds the
length (8191 bytes).
A sparc64 openprom manual page first appeared in OpenBSD
Due to limitations within the OPENPROM itself, these functions run at elevated
priority and may adversely affect system performance.
OpenBSD 3.6 October 5, 2001
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