1 files changed, 377 insertions, 0 deletions

diff --git a/lib/timer.c b/lib/timer.c
new file mode 100644
index 00000000..05e488c1
--- /dev/null
+++ b/lib/timer.c
@@ -0,0 +1,377 @@
+/*
+ *	BIRD -- Timers
+ *
+ *	(c) 2013--2017 Ondrej Zajicek <santiago@crfreenet.org>
+ *	(c) 2013--2017 CZ.NIC z.s.p.o.
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+/**
+ * DOC: Timers
+ *
+ * Timers are resources which represent a wish of a module to call a function at
+ * the specified time. The timer code does not guarantee exact timing, only that
+ * a timer function will not be called before the requested time.
+ *
+ * In BIRD, time is represented by values of the &btime type which is signed
+ * 64-bit integer interpreted as a relative number of microseconds since some
+ * fixed time point in past. The current time can be obtained by current_time()
+ * function with reasonable accuracy and is monotonic. There is also a current
+ * 'wall-clock' real time obtainable by current_real_time() reported by OS.
+ *
+ * Each timer is described by a &timer structure containing a pointer to the
+ * handler function (@hook), data private to this function (@data), time the
+ * function should be called at (@expires, 0 for inactive timers), for the other
+ * fields see |timer.h|.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "nest/bird.h"
+
+#include "lib/heap.h"
+#include "lib/resource.h"
+#include "lib/timer.h"
+
+
+struct timeloop main_timeloop;
+
+
+#ifdef USE_PTHREADS
+
+#include <pthread.h>
+
+/* Data accessed and modified from proto/bfd/io.c */
+pthread_key_t current_time_key;
+
+static inline struct timeloop *
+timeloop_current(void)
+{
+  return pthread_getspecific(current_time_key);
+}
+
+static inline void
+timeloop_init_current(void)
+{
+  pthread_key_create(&current_time_key, NULL);
+  pthread_setspecific(current_time_key, &main_timeloop);
+}
+
+void wakeup_kick_current(void);
+
+#else
+
+/* Just use main timelooop */
+static inline struct timeloop * timeloop_current(void) { return &main_timeloop; }
+static inline void timeloop_init_current(void) { }
+
+#endif
+
+btime
+current_time(void)
+{
+  return timeloop_current()->last_time;
+}
+
+btime
+current_real_time(void)
+{
+  struct timeloop *loop = timeloop_current();
+
+  if (!loop->real_time)
+    times_update_real_time(loop);
+
+  return loop->real_time;
+}
+
+
+#define TIMER_LESS(a,b)		((a)->expires < (b)->expires)
+#define TIMER_SWAP(heap,a,b,t)	(t = heap[a], heap[a] = heap[b], heap[b] = t, \
+				   heap[a]->index = (a), heap[b]->index = (b))
+
+
+static void
+tm_free(resource *r)
+{
+  timer *t = (void *) r;
+
+  tm_stop(t);
+}
+
+static void
+tm_dump(resource *r)
+{
+  timer *t = (void *) r;
+
+  debug("(code %p, data %p, ", t->hook, t->data);
+  if (t->randomize)
+    debug("rand %d, ", t->randomize);
+  if (t->recurrent)
+    debug("recur %d, ", t->recurrent);
+  if (t->expires)
+    debug("expires in %d ms)\n", (t->expires - current_time()) TO_MS);
+  else
+    debug("inactive)\n");
+}
+
+
+static struct resclass tm_class = {
+  "Timer",
+  sizeof(timer),
+  tm_free,
+  tm_dump,
+  NULL,
+  NULL
+};
+
+timer *
+tm_new(pool *p)
+{
+  timer *t = ralloc(p, &tm_class);
+  t->index = -1;
+  return t;
+}
+
+void
+tm_set(timer *t, btime when)
+{
+  struct timeloop *loop = timeloop_current();
+  uint tc = timers_count(loop);
+
+  if (!t->expires)
+  {
+    t->index = ++tc;
+    t->expires = when;
+    BUFFER_PUSH(loop->timers) = t;
+    HEAP_INSERT(loop->timers.data, tc, timer *, TIMER_LESS, TIMER_SWAP);
+  }
+  else if (t->expires < when)
+  {
+    t->expires = when;
+    HEAP_INCREASE(loop->timers.data, tc, timer *, TIMER_LESS, TIMER_SWAP, t->index);
+  }
+  else if (t->expires > when)
+  {
+    t->expires = when;
+    HEAP_DECREASE(loop->timers.data, tc, timer *, TIMER_LESS, TIMER_SWAP, t->index);
+  }
+
+#ifdef CONFIG_BFD
+  /* Hack to notify BFD loops */
+  if ((loop != &main_timeloop) && (t->index == 1))
+    wakeup_kick_current();
+#endif
+}
+
+void
+tm_start(timer *t, btime after)
+{
+  tm_set(t, current_time() + MAX(after, 0));
+}
+
+void
+tm_stop(timer *t)
+{
+  if (!t->expires)
+    return;
+
+  struct timeloop *loop = timeloop_current();
+  uint tc = timers_count(loop);
+
+  HEAP_DELETE(loop->timers.data, tc, timer *, TIMER_LESS, TIMER_SWAP, t->index);
+  BUFFER_POP(loop->timers);
+
+  t->index = -1;
+  t->expires = 0;
+}
+
+void
+timers_init(struct timeloop *loop, pool *p)
+{
+  times_init(loop);
+
+  BUFFER_INIT(loop->timers, p, 4);
+  BUFFER_PUSH(loop->timers) = NULL;
+}
+
+void io_log_event(void *hook, void *data);
+
+void
+timers_fire(struct timeloop *loop)
+{
+  btime base_time;
+  timer *t;
+
+  times_update(loop);
+  base_time = loop->last_time;
+
+  while (t = timers_first(loop))
+  {
+    if (t->expires > base_time)
+      return;
+
+    if (t->recurrent)
+    {
+      btime when = t->expires + t->recurrent;
+
+      if (when <= loop->last_time)
+	when = loop->last_time + t->recurrent;
+
+      if (t->randomize)
+	when += random() % (t->randomize + 1);
+
+      tm_set(t, when);
+    }
+    else
+      tm_stop(t);
+
+    /* This is ugly hack, we want to log just timers executed from the main I/O loop */
+    if (loop == &main_timeloop)
+      io_log_event(t->hook, t->data);
+
+    t->hook(t);
+  }
+}
+
+void
+timer_init(void)
+{
+  timers_init(&main_timeloop, &root_pool);
+  timeloop_init_current();
+}
+
+
+/**
+ * tm_parse_time - parse a date and time
+ * @x: time string
+ *
+ * tm_parse_time() takes a textual representation of a date and time
+ * (yyyy-mm-dd[ hh:mm:ss[.sss]]) and converts it to the corresponding value of
+ * type &btime.
+ */
+btime
+tm_parse_time(char *x)
+{
+  struct tm tm;
+  int usec, n1, n2, n3, r;
+
+  r = sscanf(x, "%d-%d-%d%n %d:%d:%d%n.%d%n",
+	     &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &n1,
+	     &tm.tm_hour, &tm.tm_min, &tm.tm_sec, &n2,
+	     &usec, &n3);
+
+  if ((r == 3) && !x[n1])
+    tm.tm_hour = tm.tm_min = tm.tm_sec = usec = 0;
+  else if ((r == 6) && !x[n2])
+    usec = 0;
+  else if ((r == 7) && !x[n3])
+  {
+    /* Convert subsecond digits to proper precision */
+    int digits = n3 - n2 - 1;
+    if ((usec < 0) || (usec > 999999) || (digits < 1) || (digits > 6))
+      return 0;
+
+    while (digits++ < 6)
+      usec *= 10;
+  }
+  else
+    return 0;
+
+  tm.tm_mon--;
+  tm.tm_year -= 1900;
+  s64 ts = mktime(&tm);
+  if ((ts == (s64) (time_t) -1) || (ts < 0) || (ts > ((s64) 1 << 40)))
+    return 0;
+
+  return ts S + usec;
+}
+
+/**
+ * tm_format_time - convert date and time to textual representation
+ * @x: destination buffer of size %TM_DATETIME_BUFFER_SIZE
+ * @fmt: specification of resulting textual representation of the time
+ * @t: time
+ *
+ * This function formats the given relative time value @t to a textual
+ * date/time representation (dd-mm-yyyy hh:mm:ss) in real time.
+ */
+void
+tm_format_time(char *x, struct timeformat *fmt, btime t)
+{
+  btime dt = current_time() - t;
+  btime rt = current_real_time() - dt;
+  int v1 = !fmt->limit || (dt < fmt->limit);
+
+  tm_format_real_time(x, v1 ? fmt->fmt1 : fmt->fmt2, rt);
+}
+
+/* Replace %f in format string with usec scaled to requested precision */
+static int
+strfusec(char *buf, int size, const char *fmt, uint usec)
+{
+  char *str = buf;
+  int parity = 0;
+
+  while (*fmt)
+  {
+    if (!size)
+      return 0;
+
+    if ((fmt[0] == '%') && (!parity) &&
+	((fmt[1] == 'f') || (fmt[1] >= '1') && (fmt[1] <= '6') && (fmt[2] == 'f')))
+    {
+      int digits = (fmt[1] == 'f') ? 6 : (fmt[1] - '0');
+      uint d = digits, u = usec;
+
+      /* Convert microseconds to requested precision */
+      while (d++ < 6)
+	u /= 10;
+
+      int num = bsnprintf(str, size, "%0*u", digits, u);
+      if (num < 0)
+	return 0;
+
+      fmt += (fmt[1] == 'f') ? 2 : 3;
+      ADVANCE(str, size, num);
+    }
+    else
+    {
+      /* Handle '%%' expression */
+      parity = (*fmt == '%') ? !parity : 0;
+      *str++ = *fmt++;
+      size--;
+    }
+  }
+
+  if (!size)
+    return 0;
+
+  *str = 0;
+  return str - buf;
+}
+
+void
+tm_format_real_time(char *x, const char *fmt, btime t)
+{
+  s64 t1 = t TO_S;
+  s64 t2 = t - t1 S;
+
+  time_t ts = t1;
+  struct tm tm;
+  if (!localtime_r(&ts, &tm))
+    goto err;
+
+  byte tbuf[TM_DATETIME_BUFFER_SIZE];
+  if (!strfusec(tbuf, TM_DATETIME_BUFFER_SIZE, fmt, t2))
+    goto err;
+
+  if (!strftime(x, TM_DATETIME_BUFFER_SIZE, tbuf, &tm))
+    goto err;
+
+  return;
+
+err:
+  strcpy(x, "<error>");
+}