|Kernel Functions for Drivers||drv_getparm(9F)
| ||drv_getparm - retrieve kernel state
int drv_getparm(unsigned int parm, void *value_p);
Architecture independent level 1 (DDI/DKI).
- The kernel parameter to be obtained.
Possible values are:
- 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.
- Read the process group identification number. This number
determines which processes should receive a HANGUP or BREAK signal
when detected by a driver.
- Read the process table token value.
- Read process identification number.
- Read process session identification number.
- Read time in seconds.
- Return a pointer to the caller's credential structure.
- A pointer to the data space in
which the value of the parameter is to be copied.
Since the release of the Solaris 2.6 operating environment, the drv_getparm() function has been replaced by ddi_get_lbolt(9F), ddi_get_time(9F), and ddi_get_pid(9F).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.
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.
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.