drv_getparm(9F) 					   Kernel Functions for Drivers 					   drv_getparm(9F)

NAME

       drv_getparm - retrieve kernel state information

SYNOPSIS

       #include <sys/ddi.h>

       int drv_getparm(unsigned int parm, void *value_p);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       parm	       The kernel parameter to be obtained.  Possible values are:

       "small and bold"ReadLTthe  value  of  lbolt.  lbolt is a clock_t that is unconditionally incremented by one at each clock tick.	No special
		       treatment is applied when this value overflows the maximum value of the signed integral type clock_t. When this occurs, its
		       value  will  be	negative,  and its magnitude will be decreasing until it again passes zero. It can therefore not be relied
		       upon to provide an indication of the amount of time that passes since the last system reboot, nor should it be used to mark
		       an  absolute  time  in the system. Only the difference between two measurements of lbolt is significant. It is used in this
		       way inside the system kernel for timing purposes.

       PPGRP	       Read the process group identification number.  This number determines which processes should receive a	HANGUP	or   BREAK
		       signal when detected by a driver.

       UPROCP	       Read the process table token value.

       PPID	       Read process identification number.

       PSID	       Read process session identification number.

       TIME	       Read time in seconds.

       UCRED	       Return a pointer to the caller's credential structure.

       value_p	       A pointer to the data space in which the value of the parameter is to be copied.

DESCRIPTION

       Since  the  release  of	the  Solaris  2.6  operating  environment,  the  drv_getparm()	function  has  been replaced by ddi_get_lbolt(9F),
       ddi_get_time(9F), and ddi_get_pid(9F).

       drv_getparm() function verifies that  parm corresponds to a kernel parameter that may be read.  If the value of	parm does  not	correspond
       to a parameter or corresponds to a parameter that may not be read,  -1 is returned.  Otherwise, the value of the parameter is stored in the
       data space pointed to by  value_p.

       drv_getparm() does not explicitly check to see whether the device has the appropriate context when the function is called and the  function
       does  not  check  for  correct alignment in the data space pointed to by value_p. It is the responsibility of the driver writer to use this
       function only when it is appropriate to do so and to correctly  declare the data space needed by the driver.

RETURN VALUES

       drv_getparm() returns 0 to indicate success,  -1 to indicate failure.  The value stored in the space pointed to by  value_p is the value of
       the  parameter  if  0  is  returned, or undefined if  -1 is returned. -1 is returned if you specify a value other than  LBOLT, PPGRP, PPID,
       PSID, TIME, UCRED, or  UPROCP.  Always check the return code when using this function.

CONTEXT

       drv_getparm() can be called from user context only when using PPGRP, PPID, PSID, UCRED, or UPROCP.  It can be called from user or interrupt
       context when using the LBOLT or TIME argument.

SEE ALSO

       ddi_get_lbolt(9F), ddi_get_pid(9F), ddi_get_time(9F),  buf(9S)

       Writing Device Drivers

SunOS 5.10							    24 Jun 1997 						   drv_getparm(9F)