minix/kernel/system/do_alarm.c
Jorrit Herder 42ab148155 Reorganized system call library; uses separate file per call now.
New configuration header file to include/ exclude functionality.
Extracted privileged features from struct proc and create new struct priv.
Renamed various system calls for readability.
2005-07-14 15:12:12 +00:00

77 lines
2.7 KiB
C

/* The system call implemented in this file:
* m_type: SYS_SETALARM
*
* The parameters for this system call are:
* m2_i1: ALRM_PROC_NR (set alarm for this process)
* m2_l1: ALRM_EXP_TIME (alarm's expiration time)
* m2_i2: ALRM_ABS_TIME (expiration time is absolute?)
* m2_l1: ALRM_SEC_LEFT (return seconds left of previous)
*
* Changes:
* Aug 25, 2004 fully rewritten to clean up code (Jorrit N. Herder)
*/
#include "../system.h"
#if USE_SETALARM
FORWARD _PROTOTYPE( void cause_alarm, (timer_t *tp) );
/*===========================================================================*
* do_setalarm *
*===========================================================================*/
PUBLIC int do_setalarm(m_ptr)
message *m_ptr; /* pointer to request message */
{
/* A process requests a synchronous alarm, or wants to cancel its alarm. */
int proc_nr; /* which process wants the alarm */
long exp_time; /* expiration time for this alarm */
int use_abs_time; /* use absolute or relative time */
timer_t *tp; /* the process' timer structure */
clock_t uptime; /* placeholder for current uptime */
/* Extract shared parameters from the request message. */
proc_nr = m_ptr->ALRM_PROC_NR; /* process to interrupt later */
if (SELF == proc_nr) proc_nr = m_ptr->m_source;
if (! isokprocn(proc_nr)) return(EINVAL);
exp_time = m_ptr->ALRM_EXP_TIME; /* alarm's expiration time */
use_abs_time = m_ptr->ALRM_ABS_TIME; /* flag for absolute time */
/* Get the timer structure and set the parameters for this alarm. */
tp = &(proc_addr(proc_nr)->p_priv->s_alarm_timer);
tmr_arg(tp)->ta_int = proc_nr;
tp->tmr_func = cause_alarm;
/* Return the ticks left on the previous alarm. */
uptime = get_uptime();
if ((tp->tmr_exp_time == TMR_NEVER) || (tp->tmr_exp_time < uptime) ) {
m_ptr->ALRM_TIME_LEFT = 0;
} else {
m_ptr->ALRM_TIME_LEFT = (tp->tmr_exp_time - uptime);
}
/* Finally, (re)set the timer depending on 'exp_time'. */
if (exp_time == 0) {
reset_timer(tp);
} else {
tp->tmr_exp_time = (use_abs_time) ? exp_time : exp_time + get_uptime();
set_timer(tp, tp->tmr_exp_time, tp->tmr_func);
}
return(OK);
}
/*===========================================================================*
* cause_alarm *
*===========================================================================*/
PRIVATE void cause_alarm(tp)
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 given with a SYN_ALARM message.
*/
lock_alert(CLOCK, tmr_arg(tp)->ta_int);
}
#endif /* USE_SETALARM */