--- /dev/null
+/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
+ * Junior University
+ *
+ * We are making the OpenFlow specification and associated documentation
+ * (Software) available for public use and benefit with the expectation
+ * that others will use, modify and enhance the Software and contribute
+ * those enhancements back to the community. However, since we would
+ * like to make the Software available for broadest use, with as few
+ * restrictions as possible permission is hereby granted, free of
+ * charge, to any person obtaining a copy of this Software to deal in
+ * the Software under the copyrights without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * The name and trademarks of copyright holder(s) may NOT be used in
+ * advertising or publicity pertaining to the Software or any
+ * derivatives without specific, written prior permission.
+ */
+
+#include <config.h>
+#include "timeval.h"
+#include <assert.h>
+#include <errno.h>
+#include <poll.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/time.h>
+#include "fatal-signal.h"
+#include "util.h"
+
+/* Initialized? */
+static bool inited;
+
+/* Has a timer tick occurred? */
+static volatile sig_atomic_t tick;
+
+/* The current time, as of the last refresh. */
+static struct timeval now;
+
+/* Time at which to die with SIGALRM (if not TIME_MIN). */
+static time_t deadline = TIME_MIN;
+
+static void sigalrm_handler(int);
+static void refresh_if_ticked(void);
+static time_t time_add(time_t, time_t);
+static void block_sigalrm(sigset_t *);
+static void unblock_sigalrm(const sigset_t *);
+
+/* Initializes the timetracking module. */
+void
+time_init(void)
+{
+ struct sigaction sa;
+ struct itimerval itimer;
+
+ if (inited) {
+ return;
+ }
+
+ inited = true;
+ gettimeofday(&now, NULL);
+ tick = false;
+
+ /* Set up signal handler. */
+ memset(&sa, 0, sizeof sa);
+ sa.sa_handler = sigalrm_handler;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_RESTART;
+ if (sigaction(SIGALRM, &sa, NULL)) {
+ fatal(errno, "sigaction(SIGALRM) failed");
+ }
+
+ /* Set up periodic timer. */
+ itimer.it_interval.tv_sec = 0;
+ itimer.it_interval.tv_usec = TIME_UPDATE_INTERVAL * 1000;
+ itimer.it_value = itimer.it_interval;
+ if (setitimer(ITIMER_REAL, &itimer, NULL)) {
+ fatal(errno, "setitimer failed");
+ }
+}
+
+/* Forces a refresh of the current time from the kernel. It is not usually
+ * necessary to call this function, since the time will be refreshed
+ * automatically at least every TIME_UPDATE_INTERVAL milliseconds. */
+void
+time_refresh(void)
+{
+ gettimeofday(&now, NULL);
+ tick = false;
+}
+
+/* Returns the current time, in seconds. */
+time_t
+time_now(void)
+{
+ refresh_if_ticked();
+ return now.tv_sec;
+}
+
+/* Returns the current time, in ms (within TIME_UPDATE_INTERVAL ms). */
+long long int
+time_msec(void)
+{
+ refresh_if_ticked();
+ return (long long int) now.tv_sec * 1000 + now.tv_usec / 1000;
+}
+
+/* Configures the program to die with SIGALRM 'secs' seconds from now, if
+ * 'secs' is nonzero, or disables the feature if 'secs' is zero. */
+void
+time_alarm(unsigned int secs)
+{
+ sigset_t oldsigs;
+
+ time_init();
+ block_sigalrm(&oldsigs);
+ deadline = secs ? time_add(time_now(), secs) : TIME_MIN;
+ unblock_sigalrm(&oldsigs);
+}
+
+/* Like poll(), except:
+ *
+ * - On error, returns a negative error code (instead of setting errno).
+ *
+ * - If interrupted by a signal, retries automatically until the original
+ * 'timeout' expires. (Because of this property, this function will
+ * never return -EINTR.)
+ *
+ * - As a side effect, refreshes the current time (like time_refresh()).
+ */
+int
+time_poll(struct pollfd *pollfds, int n_pollfds, int timeout)
+{
+ long long int start;
+ sigset_t oldsigs;
+ bool blocked;
+ int retval;
+
+ time_refresh();
+ start = time_msec();
+ blocked = false;
+ for (;;) {
+ int time_left;
+ if (timeout > 0) {
+ long long int elapsed = time_msec() - start;
+ time_left = timeout >= elapsed ? timeout - elapsed : 0;
+ } else {
+ time_left = timeout;
+ }
+
+ retval = poll(pollfds, n_pollfds, time_left);
+ if (retval < 0) {
+ retval = -errno;
+ }
+ if (retval != -EINTR) {
+ break;
+ }
+
+ if (!blocked && deadline == TIME_MIN) {
+ block_sigalrm(&oldsigs);
+ blocked = true;
+ }
+ time_refresh();
+ }
+ if (blocked) {
+ unblock_sigalrm(&oldsigs);
+ }
+ return retval;
+}
+
+/* Returns the sum of 'a' and 'b', with saturation on overflow or underflow. */
+static time_t
+time_add(time_t a, time_t b)
+{
+ return (a >= 0
+ ? (b > TIME_MAX - a ? TIME_MAX : a + b)
+ : (b < TIME_MIN - a ? TIME_MIN : a + b));
+}
+
+static void
+sigalrm_handler(int sig_nr)
+{
+ tick = true;
+ if (deadline != TIME_MIN && time(0) > deadline) {
+ fatal_signal_handler(sig_nr);
+ }
+}
+
+static void
+refresh_if_ticked(void)
+{
+ assert(inited);
+ if (tick) {
+ time_refresh();
+ }
+}
+
+static void
+block_sigalrm(sigset_t *oldsigs)
+{
+ sigset_t sigalrm;
+ sigemptyset(&sigalrm);
+ sigaddset(&sigalrm, SIGALRM);
+ if (sigprocmask(SIG_BLOCK, &sigalrm, oldsigs)) {
+ fatal(errno, "sigprocmask");
+ }
+}
+
+static void
+unblock_sigalrm(const sigset_t *oldsigs)
+{
+ if (sigprocmask(SIG_SETMASK, oldsigs, NULL)) {
+ fatal(errno, "sigprocmask");
+ }
+}
git://git.onelab.eu / sliver-openvswitch.git / commitdiff