1 /* The kernel call implemented in this file: 2 * m_type: SYS_SETALARM 3 * 4 * The parameters for this kernel call are: 5 * m_lsys_krn_sys_setalarm.exp_time (alarm's expiration time) 6 * m_lsys_krn_sys_setalarm.abs_time (expiration time is absolute?) 7 * m_lsys_krn_sys_setalarm.time_left (return seconds left of previous) 8 */ 9 10 #include "kernel/system.h" 11 12 #include <minix/endpoint.h> 13 #include <assert.h> 14 15 #if USE_SETALARM 16 17 static void cause_alarm(minix_timer_t *tp); 18 19 /*===========================================================================* 20 * do_setalarm * 21 *===========================================================================*/ 22 int do_setalarm(struct proc * caller, message * m_ptr) 23 { 24 /* A process requests a synchronous alarm, or wants to cancel its alarm. */ 25 long exp_time; /* expiration time for this alarm */ 26 int use_abs_time; /* use absolute or relative time */ 27 minix_timer_t *tp; /* the process' timer structure */ 28 clock_t uptime; /* placeholder for current uptime */ 29 30 /* Extract shared parameters from the request message. */ 31 exp_time = m_ptr->m_lsys_krn_sys_setalarm.exp_time; /* alarm's expiration time */ 32 use_abs_time = m_ptr->m_lsys_krn_sys_setalarm.abs_time; /* flag for absolute time */ 33 if (! (priv(caller)->s_flags & SYS_PROC)) return(EPERM); 34 35 /* Get the timer structure and set the parameters for this alarm. */ 36 tp = &(priv(caller)->s_alarm_timer); 37 tmr_arg(tp)->ta_int = caller->p_endpoint; 38 tp->tmr_func = cause_alarm; 39 40 /* Return the ticks left on the previous alarm. */ 41 uptime = get_monotonic(); 42 if (tp->tmr_exp_time == TMR_NEVER) { 43 m_ptr->m_lsys_krn_sys_setalarm.time_left = TMR_NEVER; 44 } else if (uptime < tp->tmr_exp_time) { 45 m_ptr->m_lsys_krn_sys_setalarm.time_left = (tp->tmr_exp_time - uptime); 46 } else { 47 m_ptr->m_lsys_krn_sys_setalarm.time_left = 0; 48 } 49 50 /* For the caller's convenience, also return the current time. */ 51 m_ptr->m_lsys_krn_sys_setalarm.uptime = uptime; 52 53 /* Finally, (re)set the timer depending on the expiration time. */ 54 if (exp_time == 0) { 55 reset_kernel_timer(tp); 56 } else { 57 tp->tmr_exp_time = (use_abs_time) ? exp_time : exp_time + get_monotonic(); 58 set_kernel_timer(tp, tp->tmr_exp_time, tp->tmr_func); 59 } 60 return(OK); 61 } 62 63 /*===========================================================================* 64 * cause_alarm * 65 *===========================================================================*/ 66 static void cause_alarm(minix_timer_t *tp) 67 { 68 /* Routine called if a timer goes off and the process requested a synchronous 69 * alarm. The process number is stored in timer argument 'ta_int'. Notify that 70 * process with a notification message from CLOCK. 71 */ 72 endpoint_t proc_nr_e = tmr_arg(tp)->ta_int; /* get process number */ 73 mini_notify(proc_addr(CLOCK), proc_nr_e); /* notify process */ 74 } 75 76 #endif /* USE_SETALARM */ 77