libbb: introduce and use msleep()

function                                             old     new   delta
msleep                                                 -      45     +45
watchdog_main                                        271     266      -5
common_traceroute_main                              3546    3530     -16
beep_main                                            277     248     -29
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/3 up/down: 45/-50)             Total: -5 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/libbb/bb_do_delay.c b/libbb/bb_do_delay.c
index 3a86dc2ae..3dbf032db 100644
--- a/libbb/bb_do_delay.c
+++ b/libbb/bb_do_delay.c
@@ -8,7 +8,7 @@
  */
 #include "libbb.h"
 
-/* void FAST_FUNC bb_do_delay(int seconds) { ... } - no users yet */
+/* void FAST_FUNC bb_do_delay(unsigned seconds) { ... } - no users yet */
 
 #ifndef LOGIN_FAIL_DELAY
 #define LOGIN_FAIL_DELAY 3
@@ -34,3 +34,16 @@ void FAST_FUNC sleep1(void)
         sleep(1);
 }
 
+void FAST_FUNC msleep(unsigned ms)
+{
+        /* 1. usleep(n) is not guaranteed by standards to accept n >= 1000000
+         * 2. multiplication in usleep(ms * 1000) can overflow if ms > 4294967
+         *    (sleep of ~71.5 minutes)
+         * Let's play safe and loop:
+         */
+        while (ms > 500) {
+                usleep(500000);
+                ms -= 500;
+        }
+        usleep(ms * 1000);
+}