| 1 | /* The kernel call implemented in this file:
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| 2 | * m_type: SYS_SETALARM
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| 3 | *
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| 4 | * The parameters for this kernel call are:
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| 5 | * m2_l1: ALRM_EXP_TIME (alarm's expiration time)
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| 6 | * m2_i2: ALRM_ABS_TIME (expiration time is absolute?)
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| 7 | * m2_l1: ALRM_TIME_LEFT (return seconds left of previous)
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| 8 | */
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| 9 |
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| 10 | #include "../system.h"
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| 11 |
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| 12 | #if USE_SETALARM
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| 13 |
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| 14 | FORWARD _PROTOTYPE( void cause_alarm, (timer_t *tp) );
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| 15 |
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| 16 | /*===========================================================================*
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| 17 | * do_setalarm *
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| 18 | *===========================================================================*/
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| 19 | PUBLIC int do_setalarm(m_ptr)
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| 20 | message *m_ptr; /* pointer to request message */
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| 21 | {
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| 22 | /* A process requests a synchronous alarm, or wants to cancel its alarm. */
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| 23 | register struct proc *rp; /* pointer to requesting process */
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| 24 | int proc_nr; /* which process wants the alarm */
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| 25 | long exp_time; /* expiration time for this alarm */
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| 26 | int use_abs_time; /* use absolute or relative time */
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| 27 | timer_t *tp; /* the process' timer structure */
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| 28 | clock_t uptime; /* placeholder for current uptime */
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| 29 |
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| 30 | /* Extract shared parameters from the request message. */
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| 31 | exp_time = m_ptr->ALRM_EXP_TIME; /* alarm's expiration time */
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| 32 | use_abs_time = m_ptr->ALRM_ABS_TIME; /* flag for absolute time */
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| 33 | proc_nr = m_ptr->m_source; /* process to interrupt later */
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| 34 | rp = proc_addr(proc_nr);
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| 35 | if (! (priv(rp)->s_flags & SYS_PROC)) return(EPERM);
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| 36 |
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| 37 | /* Get the timer structure and set the parameters for this alarm. */
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| 38 | tp = &(priv(rp)->s_alarm_timer);
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| 39 | tmr_arg(tp)->ta_int = proc_nr;
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| 40 | tp->tmr_func = cause_alarm;
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| 41 |
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| 42 | /* Return the ticks left on the previous alarm. */
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| 43 | uptime = get_uptime();
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| 44 | if ((tp->tmr_exp_time != TMR_NEVER) && (uptime < tp->tmr_exp_time) ) {
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| 45 | m_ptr->ALRM_TIME_LEFT = (tp->tmr_exp_time - uptime);
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| 46 | } else {
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| 47 | m_ptr->ALRM_TIME_LEFT = 0;
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| 48 | }
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| 49 |
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| 50 | /* Finally, (re)set the timer depending on the expiration time. */
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| 51 | if (exp_time == 0) {
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| 52 | reset_timer(tp);
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| 53 | } else {
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| 54 | tp->tmr_exp_time = (use_abs_time) ? exp_time : exp_time + get_uptime();
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| 55 | set_timer(tp, tp->tmr_exp_time, tp->tmr_func);
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| 56 | }
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| 57 | return(OK);
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| 58 | }
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| 59 |
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| 60 | /*===========================================================================*
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| 61 | * cause_alarm *
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| 62 | *===========================================================================*/
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| 63 | PRIVATE void cause_alarm(tp)
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| 64 | timer_t *tp;
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| 65 | {
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| 66 | /* Routine called if a timer goes off and the process requested a synchronous
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| 67 | * alarm. The process number is stored in timer argument 'ta_int'. Notify that
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| 68 | * process with a notification message from CLOCK.
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| 69 | */
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| 70 | int proc_nr = tmr_arg(tp)->ta_int; /* get process number */
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| 71 | lock_notify(CLOCK, proc_nr); /* notify process */
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| 72 | }
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| 73 |
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| 74 | #endif /* USE_SETALARM */
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