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         p = mmap(NULL, size, PROT_READ | PROT_WRITE,
  24                 MAP_PREALLOC | MAP_CONTIG | MAP_ANON, -1, 0);
  25         if (p == MAP_FAILED)
  26                 panic(__FILE__, "out of memory", size);
  27
  28         return p;
  29 }
  30
  31 /*===========================================================================*
  32  *                              flt_free                                     *
  33  *===========================================================================*/
  34 void flt_free(char *buf, size_t size, char *sbuf)
  35 {
  36         /* Free a buffer previously allocated with flt_malloc().
  37          */
  38
  39         if(buf != sbuf)
  40                 munmap(buf, size);
  41 }
  42
  43 /*===========================================================================*
  44  *                              print64                                      *
  45  *===========================================================================*/
  46 char *print64(u64_t p)
  47 {
  48 #define NB 10
  49         static int n = 0;
  50         static char buf[NB][100];
  51         u32_t lo = ex64lo(p), hi = ex64hi(p);
  52         n = (n+1) % NB;
  53         if(!hi) sprintf(buf[n], "%lx", lo);
  54         else sprintf(buf[n], "%lx%08lx", hi, lo);
  55         return buf[n];
  56 }
  57
  58 /*===========================================================================*
  59  *                              flt_alarm                                    *
  60  *===========================================================================*/
  61 clock_t flt_alarm(clock_t dt)
  62 {
  63         int r;
  64
  65         if(dt < 0)
  66                 return next_alarm;
  67
  68         r = sys_setalarm(dt, 0);
  69
  70         if(r != OK)
  71                 panic(__FILE__, "sys_setalarm failed", r);
  72
  73         if(dt == 0) {
  74                 if(!next_alarm)
  75                         panic(__FILE__, "clearing unset alarm", r);
  76                 next_alarm = 0;
  77         } else {
  78                 if(next_alarm)
  79                         panic(__FILE__, "overwriting alarm", r);
  80                 if ((r = getuptime(&next_alarm)) != OK)
  81                         panic(__FILE__, "getuptime failed", r);
  82                 next_alarm += dt;
  83         }
  84
  85         return next_alarm;
  86 }
  87
  88 /*===========================================================================*
  89  *                              got_alarm                                    *
  90  *===========================================================================*/
  91 static void got_alarm(int sig)
  92 {
  93         /* Do nothing. */
  94 }
  95
  96 /*===========================================================================*
  97  *                              flt_sleep                                    *
  98  *===========================================================================*/
  99 void flt_sleep(int secs)
 100 {
 101         /* Sleep for the given number of seconds. Don't use sleep(), as that
 102          * will end up calling select() to VFS. This implementation could be
 103          * improved.
 104          */
 105
 106         signal(SIGALRM, got_alarm);
 107         alarm(secs);
 108
 109         pause();
 110 }