libbb/bb_do_delay.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Busybox utility routines.
   4  *
   5  * Copyright (C) 2005 by Tito Ragusa <tito-wolit@tiscali.it>
   6  *
   7  * Licensed under GPLv2, see file LICENSE in this source tree.
   8  */
   9 #include "libbb.h"
  10
  11 /* void FAST_FUNC bb_do_delay(unsigned seconds) { ... } - no users yet */
  12
  13 #ifndef LOGIN_FAIL_DELAY
  14 #define LOGIN_FAIL_DELAY 3
  15 #endif
  16 void FAST_FUNC pause_after_failed_login(void)
  17 {
  18 #if 0 /* over-engineered madness */
  19         time_t end, diff;
  20
  21         end = time(NULL) + LOGIN_FAIL_DELAY;
  22         diff = LOGIN_FAIL_DELAY;
  23         do {
  24                 sleep(diff);
  25                 diff = end - time(NULL);
  26         } while (diff > 0);
  27 #else
  28         sleep(LOGIN_FAIL_DELAY);
  29 #endif
  30 }
  31
  32 void FAST_FUNC sleep1(void)
  33 {
  34         sleep(1);
  35 }
  36
  37 void FAST_FUNC msleep(unsigned ms)
  38 {
  39 #if 0
  40         /* 1. usleep(n) is not guaranteed by standards to accept n >= 1000000
  41          * 2. multiplication in usleep(ms * 1000) can overflow if ms > 4294967
  42          *    (sleep of ~71.5 minutes)
  43          * Let's play safe and loop:
  44          */
  45         while (ms > 500) {
  46                 usleep(500000);
  47                 ms -= 500;
  48         }
  49         usleep(ms * 1000);
  50 #else
  51 //usleep is often implemented as a call to nanosleep.
  52 //Simply do the same to implement msleep.
  53 //it's marginally larger, but wakes your CPU less often:
  54 //function    old     new   delta
  55 //msleep       45      52      +7
  56         struct timespec ts;
  57         ts.tv_sec = ms / 1000;
  58         ts.tv_nsec = (ms % 1000) * 1000000;
  59         /*
  60          * If a signal has non-default handler, nanosleep returns early.
  61          * Our version of msleep doesn't return early
  62          * if interrupted by such signals:
  63          */
  64         while (nanosleep(&ts, &ts) != 0)
  65                 continue;
  66 #endif
  67 }