minix/kernel/system/clock.c

/* The system call implemented in this file:
 *   m_type:	SYS_TIMES
 *
 * The parameters for this system call are:
 *    m4_l1:	T_PROC_NR		(get info for this process)	
 *    m4_l1:	T_USER_TIME		(return values ...)	
 *    m4_l2:	T_SYSTEM_TIME	
 *    m4_l5:	T_BOOT_TICKS	
 */

#include "../kernel.h"
#include "../system.h"
#include <signal.h>

/*===========================================================================*
 *				do_times				     *
 *===========================================================================*/
PUBLIC int do_times(m_ptr)
register message *m_ptr;	/* pointer to request message */
{
/* Handle sys_times().  Retrieve the accounting information. */

  register struct proc *rp;
  int proc_nr;

  /* Insert the times needed by the SYS_TIMES system call in the message. */
  proc_nr = (m_ptr->T_PROC_NR == SELF) ? m_ptr->m_source : m_ptr->T_PROC_NR;
  if (isokprocn(proc_nr)) {
      rp = proc_addr(m_ptr->T_PROC_NR);

      lock();			/* halt the volatile time counters in rp */
      m_ptr->T_USER_TIME   = rp->p_user_time;
      m_ptr->T_SYSTEM_TIME = rp->p_sys_time;
      unlock();
  }
  m_ptr->T_BOOT_TICKS = get_uptime();  
  return(OK);
}


/* The system call implemented in this file:
 *   m_type:	SYS_SIGNALRM, SYS_SYNCALRM 
 *
 * 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)  
 */

FORWARD _PROTOTYPE( void cause_syncalrm, (timer_t *tp) );
FORWARD _PROTOTYPE( void cause_signalrm, (timer_t *tp) );

/*===========================================================================*
 *				do_setalarm				     *
 *===========================================================================*/
PUBLIC int do_setalarm(m_ptr)
message *m_ptr;			/* pointer to request message */
{
/* A process requests an alarm, or wants to cancel its alarm. This function
 * is shared used for both the SYS_SIGNALRM and SYS_SYNCALRM.
 */
  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_alarm_timer);	
  tmr_arg(tp)->ta_int = proc_nr;	
  switch (m_ptr->m_type) {
  case SYS_SYNCALRM: 	tp->tmr_func = cause_syncalrm; 		break;
  case SYS_SIGNALRM: 	tp->tmr_func = cause_signalrm; 		break;
  default:		return(EINVAL);		/* invalid alarm type */
  }

  /* 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_signalrm				     *
 *===========================================================================*/
PRIVATE void cause_signalrm(tp)
timer_t *tp;
{
/* Routine called if a timer goes off for a process that requested an SIGALRM
 * signal using the alarm(2) system call. The timer argument 'ta_int' contains
 * the process number of the process to signal.
 */
  cause_sig(tmr_arg(tp)->ta_int, SIGALRM);
}


/*===========================================================================*
 *				cause_syncalrm				     *
 *===========================================================================*/
PRIVATE void cause_syncalrm(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.
 */
  message m;
  m.NOTIFY_TYPE = SYN_ALARM;
  m.NOTIFY_ARG = get_uptime();
  m.NOTIFY_FLAGS = 0;
  lock_notify(tmr_arg(tp)->ta_int, &m);
}