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/* 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(int proc_nr_e);
/*===========================================================================*
* 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;
use_abs_time = m_ptr->m_lsys_krn_sys_setalarm.abs_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);
/* Return the ticks left on the previous alarm. */
uptime = get_monotonic();
if (!tmr_is_set(tp)) {
m_ptr->m_lsys_krn_sys_setalarm.time_left = TMR_NEVER;
} else if (tmr_is_first(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;
}
/* For the caller's convenience, also return the current time. */
m_ptr->m_lsys_krn_sys_setalarm.uptime = uptime;
/*
* Finally, (re)set the timer depending on the expiration time. Note that
* an absolute time of zero is as valid as any other absolute value, so only
* a relative time value of zero resets the timer.
*/
if (!use_abs_time && exp_time == 0) {
reset_kernel_timer(tp);
} else {
if (!use_abs_time)
exp_time += uptime;
set_kernel_timer(tp, exp_time, cause_alarm, caller->p_endpoint);
}
return(OK);
}
/*===========================================================================*
* cause_alarm *
*===========================================================================*/
static void cause_alarm(int proc_nr_e)
{
/* Routine called if a timer goes off and the process requested a synchronous
* alarm. The process number is stored as the timer argument. Notify that
* process with a notification message from CLOCK.
*/
mini_notify(proc_addr(CLOCK), proc_nr_e); /* notify process */
}
#endif /* USE_SETALARM */
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