drivers/filter/util.c

   1 /* Filter driver - utility functions */
   2
   3 #include "inc.h"
   4 #include <sys/mman.h>
   5 #include <signal.h>
   6
   7 static clock_t next_alarm;
   8
   9 /*===========================================================================*
  10  *                              flt_malloc                                   *
  11  *===========================================================================*/
  12 char *flt_malloc(size_t size, char *sbuf, size_t ssize)
  13 {
  14         /* Allocate a buffer for 'size' bytes. If 'size' is equal to or less
  15          * than 'ssize', return the static buffer 'sbuf', otherwise, use
  16          * malloc() to allocate memory dynamically.
  17          */
  18         char *p;
  19
  20         if (size <= ssize)
  21                 return sbuf;
  22
  23         if(!(p = alloc_contig(size, 0, NULL)))
  24                 panic("out of memory: %d", size);
  25
  26         return p;
  27 }
  28
  29 /*===========================================================================*
  30  *                              flt_free                                     *
  31  *===========================================================================*/
  32 void flt_free(char *buf, size_t size, const char *sbuf)
  33 {
  34         /* Free a buffer previously allocated with flt_malloc().
  35          */
  36
  37         if(buf != sbuf)
  38                 free_contig(buf, size);
  39 }
  40
  41 /*===========================================================================*
  42  *                              flt_alarm                                    *
  43  *===========================================================================*/
  44 clock_t flt_alarm(clock_t dt)
  45 {
  46         int r;
  47
  48         if(dt < 0)
  49                 return next_alarm;
  50
  51         r = sys_setalarm(dt, 0);
  52
  53         if(r != OK)
  54                 panic("sys_setalarm failed: %d", r);
  55
  56         if(dt == 0) {
  57                 if(!next_alarm)
  58                         panic("clearing unset alarm: %d", r);
  59                 next_alarm = 0;
  60         } else {
  61                 if(next_alarm)
  62                         panic("overwriting alarm: %d", r);
  63                 if ((r = getuptime(&next_alarm)) != OK)
  64                         panic("getuptime failed: %d", r);
  65                 next_alarm += dt;
  66         }
  67
  68         return next_alarm;
  69 }
  70