72 lines
2.6 KiB
C
72 lines
2.6 KiB
C
/* The kernel call implemented in this file:
|
|
* m_type: SYS_SETALARM
|
|
*
|
|
* The parameters for this kernel call are:
|
|
* m_lsys_krn_sys_setalarm.exp_time (alarm's expiration time)
|
|
* m_lsys_krn_sys_setalarm.abs_time (expiration time is absolute?)
|
|
* m_lsys_krn_sys_setalarm.time_left (return seconds left of previous)
|
|
*/
|
|
|
|
#include "kernel/system.h"
|
|
|
|
#include <minix/endpoint.h>
|
|
#include <assert.h>
|
|
|
|
#if USE_SETALARM
|
|
|
|
static void cause_alarm(minix_timer_t *tp);
|
|
|
|
/*===========================================================================*
|
|
* do_setalarm *
|
|
*===========================================================================*/
|
|
int do_setalarm(struct proc * caller, message * m_ptr)
|
|
{
|
|
/* A process requests a synchronous alarm, or wants to cancel its alarm. */
|
|
long exp_time; /* expiration time for this alarm */
|
|
int use_abs_time; /* use absolute or relative time */
|
|
minix_timer_t *tp; /* the process' timer structure */
|
|
clock_t uptime; /* placeholder for current uptime */
|
|
|
|
/* Extract shared parameters from the request message. */
|
|
exp_time = m_ptr->m_lsys_krn_sys_setalarm.exp_time; /* alarm's expiration time */
|
|
use_abs_time = m_ptr->m_lsys_krn_sys_setalarm.abs_time; /* flag for absolute time */
|
|
if (! (priv(caller)->s_flags & SYS_PROC)) return(EPERM);
|
|
|
|
/* Get the timer structure and set the parameters for this alarm. */
|
|
tp = &(priv(caller)->s_alarm_timer);
|
|
tmr_arg(tp)->ta_int = caller->p_endpoint;
|
|
tp->tmr_func = cause_alarm;
|
|
|
|
/* Return the ticks left on the previous alarm. */
|
|
uptime = get_monotonic();
|
|
if ((tp->tmr_exp_time != TMR_NEVER) && (uptime < tp->tmr_exp_time) ) {
|
|
m_ptr->m_lsys_krn_sys_setalarm.time_left = (tp->tmr_exp_time - uptime);
|
|
} else {
|
|
m_ptr->m_lsys_krn_sys_setalarm.time_left = 0;
|
|
}
|
|
|
|
/* Finally, (re)set the timer depending on the expiration time. */
|
|
if (exp_time == 0) {
|
|
reset_kernel_timer(tp);
|
|
} else {
|
|
tp->tmr_exp_time = (use_abs_time) ? exp_time : exp_time + get_monotonic();
|
|
set_kernel_timer(tp, tp->tmr_exp_time, tp->tmr_func);
|
|
}
|
|
return(OK);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* cause_alarm *
|
|
*===========================================================================*/
|
|
static void cause_alarm(minix_timer_t *tp)
|
|
{
|
|
/* Routine called if a timer goes off and the process requested a synchronous
|
|
* alarm. The process number is stored in timer argument 'ta_int'. Notify that
|
|
* process with a notification message from CLOCK.
|
|
*/
|
|
endpoint_t proc_nr_e = tmr_arg(tp)->ta_int; /* get process number */
|
|
mini_notify(proc_addr(CLOCK), proc_nr_e); /* notify process */
|
|
}
|
|
|
|
#endif /* USE_SETALARM */
|