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:

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       Since  the  release  of	the  Solaris  2.6  operating  environment,  the  drv_getparm()	function  has  been replaced by ddi_get_lbolt(9F),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

       The 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.

       The drv_getparm() function 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

       The drv_getparm() function 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

       The drv_getparm() function can be called from user context only when using PPGRP, PPID, PSID, UCRED, or UPROCP. It can be called from user,
       interrupt, or kernel 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 5.11							    16 Jan 2006 						   drv_getparm(9F)