Manual Pages for UNIX Operating System command usage for man drv_getparm

Kernel Functions for Drivers                      drv_getparm(9F)



NAME
     drv_getparm - retrieve kernel state information

SYNOPSIS
     #include 

     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
               represents  the number of clock ticks since system
               boot. 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 indica-
               tion 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  differ-
               ence between two measurements of lbolt is signifi-
               cant. 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 struc-
               ture.



SunOS 5.11           Last change: 4 Sep 2009                    1






Kernel Functions for Drivers                      drv_getparm(9F)



     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     the    drv_getparm()   function   has   been   replaced   by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           Last change: 4 Sep 2009                    2