DOOR_GETPARAM(3C) Standard C Library Functions DOOR_GETPARAM(3C)

NAME


door_getparam, door_setparam - retrieve and set door parameters

SYNOPSIS


cc -mt [ flag... ] file... [ library... ]
#include <door.h>

int door_getparam(int d, int param, size_t *out);


int door_setparam(int d, int param, size_t val);


DESCRIPTION


The door_getparam() function retrieves the value of param for the door
descriptor d and writes it through the pointer out. The door_setparam()
function sets the value of param for the door descriptor d to val. The
param argument names the parameter to view or change and can be one of
the following values:

DOOR_PARAM_DATA_MAX
This parameter represents the maximum amount of
data that can be passed to the door routine. Any
attempt to call door_call(3C) on a door with a
data_size value larger than the door's
DOOR_PARAM_DATA_MAX parameter will fail with
ENOBUFS. At door creation time, this parameter is
initialized to SIZE_MAX and can be set to any
value from 0 to SIZE_MAX, inclusive. This
parameter must be greater than or equal to the
DOOR_PARAM_DATA_MIN parameter.


DOOR_PARAM_DATA_MIN
This parameter represents the minimum amount of
data that can be passed to the door routine. Any
attempt to call door_call(3C) on a door with a
data_size value smaller than the door's
DOOR_PARAM_DATA_MIN parameter will fail with
ENOBUFS. At door creation time, this parameter is
initialized to 0, and can be set to any value from
0 to SIZE_MAX, inclusive. This parameter must be
less than or equal to the DOOR_PARAM_DATA_MAX
parameter.


DOOR_PARAM_DESC_MAX
This parameter represents the maximum number of
argument descriptors that can be passed to the
door routine. Any attempt to call door_call(3C) on
a door with a desc_num value larger than the
door's DOOR_PARAM_DESC_MAX parameter will fail
with ENFILE. If the door was created with the
DOOR_REFUSE_DESC flag, this parameter is
initialized to 0 and cannot be changed to any
other value. Otherwise, it is initialized to
INT_MAX and can be set to any value from 0 to
INT_MAX, inclusive.


The door_setparam() function can only affect doors that were created by
the current process.

RETURN VALUES


Upon successful completion, 0 is returned. Otherwise, -1 is returned and
errno is set to indicate the error.

ERRORS


The door_getparam() function will fail if:

EBADF
The d argument is not a door descriptor.


EFAULT
The out argument is not a valid address.


EINVAL
The param argument is not a recognized parameter.


EOVERFLOW
The value of the parameter is larger than the SIZE_MAX. This
condition can occur only if the calling process is 32-bit
and the door targets a 64-bit process or the kernel.


The door_setparam() function will fail if:

EBADF
The d argument is not a door descriptor or has been revoked.


EINVAL
The param argument is not a recognized parameter, or the
requested change would make DOOR_PARAM_DATA_MIN greater than
DOOR_PARAM_DATA_MAX.


ENOTSUP
The param argument is DOOR_PARAM_DESC_MAX, d was created with
the DOOR_REFUSE_DESC flag, and val is not zero.


EPERM
The d argument was not created by this process.


ERANGE
The val argument is not in supported range of param.


EXAMPLES


Example 1: Set up a door with a fixed request size.



typedef struct my_request {
int request;
ar buffer[4096];
} my_request_t;

fd = door_create(my_handler, DOOR_REFUSE_DESC);
if (fd < 0)
/* handle error */

if (door_setparam(fd, DOOR_PARAM_DATA_MIN,
sizeof (my_request_t)) < 0 ||
door_setparam(fd, DOOR_PARAM_DATA_MAX,
sizeof (my_request_t)) < 0)
/* handle error */

/*
* the door will only accept door_call(3C)s with a
* data_size which is exactly sizeof (my_request_t).
*/


ATTRIBUTES


See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Stable |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO


door_call(3C), door_create(3C), attributes(7)

NOTES


The parameters that can be manipulated by door_setparam() are not the
only limitation on the size of requests. If the door server thread's
stack size is not large enough to hold all of the data requested plus
room for processing the request, the door call will fail with E2BIG.


The DOOR_PARAM_DATA_MIN parameter will not prevent DOOR_UNREF_DATA
notifications from being sent to the door.

illumos April 9, 2016 DOOR_GETPARAM(3C)