[UNIKRAFT/APPHELLOWORLD PATCH 2/6] Use nanosleep

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

Introduces `millisleep()` in order to enable shorter sleep times than in
seconds.

Signed-off-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
---
 main.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/main.c b/main.c
index a0d6a73..4d4210e 100644
--- a/main.c
+++ b/main.c
@@ -1,11 +1,13 @@
 #include <stdio.h>
-#include <unistd.h>
 #include <uk/essentials.h>
 
 /* Import user configuration: */
 #include <uk/config.h>
 
 #if CONFIG_APPHELLOWORLD_SPINNER
+#include <time.h>
+#include <errno.h>
+
 static const char *spinner[] = {
        ">))'>        ",
        " >))'>       ",
@@ -20,6 +22,18 @@ static const char *spinner[] = {
        " <'((<       ",
        "<'((<        ",
 };
+
+static void millisleep(unsigned int millisec)
+{
+       struct timespec ts;
+       int ret;
+
+       ts.tv_sec = millisec / 1000;
+       ts.tv_nsec = (millisec % 1000) * 1000000;
+       do
+               ret = nanosleep(&ts, &ts);
+       while (ret && errno == EINTR);
+}
 #endif /* CONFIG_APPHELLOWORLD_SPINNER */
 
 int main(int argc, char *argv[])
@@ -43,7 +57,7 @@ int main(int argc, char *argv[])
        while (1) {
                i %= ARRAY_SIZE(spinner);
                printf("\r%s", spinner[i++]);
-               sleep(1);
+               millisleep(1000);
        }
 #endif /* CONFIG_APPHELLOWORLD_SPINNER */
 }
-- 
2.20.1