drv_getparm(D3)drv_getparm(D3)NAMEdrv_getparm - retrieve kernel state information
SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
int drv_getparm(ulong_t parm, ulong_t *value_p);
Arguments
parm The kernel parameter to be obtained.
value_p A pointer to the data space into which the value of the
parameter is to be copied.
DESCRIPTIONdrv_getparm returns the value of the parameter specified by parm in the
location pointed to by value_p.
Return Values
On success, drv_getparm returns 0. On failure it returns -1 to indicate
that parm specified an invalid parameter.
USAGEdrv_getparm does not explicitly check to see whether the driver has the
appropriate context when the function is called. It is the
responsibility of the driver to use this function only when it is
appropriate to do so and to correctly declare the data space needed.
Valid values for parm are:
LBOLT Read the number of clock ticks since the last system
reboot. The difference between the values returned from
successive calls to retrieve this parameter provides an
indication of the elapsed time between the calls in units
of clock ticks. The length of a clock tick can vary
across different implementations, and therefore drivers
should not include any hard-coded assumptions about the
length of a tick. The drv_hztousec(D3) and
drv_usectohz(D3) functions can be used, as necessary, to
convert between clock ticks and microseconds
(implementation independent units).
TIME Read the time in seconds. This is the same time value
that is returned by the time(2) system call. The value is
defined as the time in seconds since 00:00:00 GMT, January
1, 1970. This definition presupposes that the
administrator has set the correct system date and time.
UCRED Retrieve a pointer to the credential structure describing
the current user credentials for the current process. The
value returned in *value_p is of type (cred_t *) and the
only valid use of the value is as an argument to
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drv_getparm(D3)drv_getparm(D3)drv_priv(D3). Since this value is associated with the
current process, the caller must have process context
(that is, must be at base level) when attempting to
retrieve this value. Also, this value should only be used
in the context of the process in which it was retrieved.
PGRP Read the process group identification number. This number
determines which processes should receive a HANGUP or
BREAK signal when detected by a driver.
PPID Read process identification number.
PSID Read process identification number.
Level
Base only when using the UCREDP argument values.
Initialization, Base, or Interrupt when using the LBOLT or TIME argument
values.
Synchronization Constraints
Does not sleep.
Driver-defined basic locks, read/write locks, and sleep locks may be held
across calls to this function
REFERENCESdrv_hztousec(D3), drv_priv(D3), drv_usectohz(D3)
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