Add the alarm library, first draft.

1 files changed, 47 insertions, 0 deletions

diff --git a/src/libstddjb/alarm_deadline.c b/src/libstddjb/alarm_deadline.c
new file mode 100644
index 0000000..768ee5c
--- /dev/null
+++ b/src/libstddjb/alarm_deadline.c
@@ -0,0 +1,47 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+#include <skalibs/tai.h>
+#include <skalibs/alarm.h>
+
+#ifdef SKALIBS_HASTIMER
+
+#include <errno.h>
+#include <signal.h>
+#include <time.h>
+#include "alarm-internal.h"
+
+#undef MYCLOCK
+#ifdef SKALIBS_HASCLOCKMON
+# define MYCLOCK CLOCK_MONOTONIC
+#else
+# define MYCLOCK CLOCK_REALTIME
+#endif
+
+int alarm_deadline (tain_t const *deadline)
+{
+  struct itimerspec it = { .it_interval = { .tv_sec = 0, .tv_nsec = 0 } } ;
+  struct sigevent se = { .sigev_notify = SIGEV_SIGNAL, .sigev_signo = SIGALRM, .sigev_value = { .sival_int = 0 }, .sigev_notify_function = 0, .sigev_notify_attributes = 0 } ;
+  if (!timespec_from_tain(&it.it_value, deadline)) return 0 ;
+  if (timer_create(MYCLOCK, &se, &timer_here) < 0) return 0 ;
+  if (timer_settime(timer_here, TIMER_ABSTIME, &it, 0) < 0)
+  {
+    int e = errno ;
+    timer_delete(timer_here) ;
+    errno = e ;
+    return 0 ;
+  }
+  return 1 ;
+}
+
+#else
+
+int alarm_deadline (tain_t const *deadline)
+{
+  tain_t tto ;
+  tain_now(&tto) ;
+  tain_sub(&tto, deadline, &tto) ;
+  return alarm_timeout(&tto) ;
+}
+
+#endif