root/kernel/itimer.c

/* */

DEFINITIONS

1. tvtojiffies
2. jiffiestotv
3. _getitimer
4. sys_getitimer
5. _setitimer
6. sys_setitimer

   1 /*
   2  * linux/kernel/itimer.c
   3  *
   4  * Copyright (C) 1992 Darren Senn
   5  */
   6 
   7 /* These are all the functions necessary to implement itimers */
   8 
   9 #include <linux/signal.h>
  10 #include <linux/sched.h>
  11 #include <linux/string.h>
  12 #include <linux/errno.h>
  13 #include <linux/time.h>
  14 
  15 #include <asm/segment.h>
  16 
  17 static unsigned long tvtojiffies(struct timeval *value)
     /*  */
  18 {
  19         return((unsigned long )value->tv_sec * HZ +
  20                 (unsigned long )(value->tv_usec + (1000000 / HZ - 1)) /
  21                 (1000000 / HZ));
  22 }
  23 
  24 static void jiffiestotv(unsigned long jiffies, struct timeval *value)
     /*  */
  25 {
  26         value->tv_usec = (jiffies % HZ) * (1000000 / HZ);
  27         value->tv_sec = jiffies / HZ;
  28         return;
  29 }
  30 
  31 int _getitimer(int which, struct itimerval *value)
     /*  */
  32 {
  33         register unsigned long val, interval;
  34 
  35         switch (which) {
  36         case ITIMER_REAL:
  37                 val = current->it_real_value;
  38                 interval = current->it_real_incr;
  39                 break;
  40         case ITIMER_VIRTUAL:
  41                 val = current->it_virt_value;
  42                 interval = current->it_virt_incr;
  43                 break;
  44         case ITIMER_PROF:
  45                 val = current->it_prof_value;
  46                 interval = current->it_prof_incr;
  47                 break;
  48         default:
  49                 return(-EINVAL);
  50         }
  51         jiffiestotv(val, &value->it_value);
  52         jiffiestotv(interval, &value->it_interval);
  53         return(0);
  54 }
  55 
  56 int sys_getitimer(int which, struct itimerval *value)
     /*  */
  57 {
  58         struct itimerval get_buffer;
  59         int k;
  60 
  61         if (!value)
  62                 return -EFAULT;
  63         k = _getitimer(which, &get_buffer);
  64         if (k < 0)
  65                 return k;
  66         verify_area(value, sizeof(struct itimerval));
  67         memcpy_tofs(value, &get_buffer, sizeof(get_buffer));
  68         return 0;
  69 }
  70 
  71 int _setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
     /*  */
  72 {
  73         register unsigned long i, j;
  74         int k;
  75 
  76         i = tvtojiffies(&value->it_interval);
  77         j = tvtojiffies(&value->it_value);
  78         if (ovalue && (k = _getitimer(which, ovalue)) < 0)
  79                 return k;
  80         switch (which) {
  81                 case ITIMER_REAL:
  82                         current->it_real_value = j;
  83                         current->it_real_incr = i;
  84                         break;
  85                 case ITIMER_VIRTUAL:
  86                         current->it_virt_value = j;
  87                         current->it_virt_incr = i;
  88                         break;
  89                 case ITIMER_PROF:
  90                         current->it_prof_value = j;
  91                         current->it_prof_incr = i;
  92                         break;
  93                 default:
  94                         return -EINVAL;
  95         }
  96         return 0;
  97 }
  98 
  99 int sys_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
     /*  */
 100 {
 101         struct itimerval set_buffer, get_buffer;
 102         int k;
 103 
 104         if (!value)
 105                 memset((char *) &set_buffer, 0, sizeof(set_buffer));
 106         else
 107                 memcpy_fromfs(&set_buffer, value, sizeof(set_buffer));
 108         k = _setitimer(which, &set_buffer, ovalue ? &get_buffer : 0);
 109         if (k < 0 || !ovalue)
 110                 return k;
 111         verify_area(ovalue, sizeof(struct itimerval));
 112         memcpy_tofs(ovalue, &get_buffer, sizeof(get_buffer));
 113         return 0;
 114 }

/* */