Adding upstream version 4.6.upstream/4.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 272 insertions, 0 deletions

diff --git a/leapdb.c b/leapdb.c
new file mode 100644
index 0000000..e4b2f9f
--- /dev/null
+++ b/leapdb.c
@@ -0,0 +1,272 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2009-2018, 2020, 2022
+ * Copyright (C) Patrick Oppenlander 2023, 2024
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ **********************************************************************
+
+  =======================================================================
+
+  This module provides leap second information. */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "conf.h"
+#include "leapdb.h"
+#include "logging.h"
+#include "util.h"
+
+/* ================================================== */
+
+/* Source of leap second data */
+enum {
+  SRC_NONE,
+  SRC_TIMEZONE,
+  SRC_LIST,
+} leap_src;
+
+/* Offset between leap-seconds.list timestamp epoch and Unix epoch.
+   leap-seconds.list epoch is 1 Jan 1900, 00:00:00 */
+#define LEAP_SEC_LIST_OFFSET 2208988800
+
+/* ================================================== */
+
+static NTP_Leap
+get_tz_leap(time_t when, int *tai_offset)
+{
+  struct tm stm, *tm;
+  time_t t;
+  char *tz_env, tz_orig[128];
+  NTP_Leap tz_leap = LEAP_Normal;
+
+  tm = gmtime(&when);
+  if (!tm)
+    return tz_leap;
+
+  stm = *tm;
+
+  /* Temporarily switch to the timezone containing leap seconds */
+  tz_env = getenv("TZ");
+  if (tz_env) {
+    if (strlen(tz_env) >= sizeof (tz_orig))
+      return tz_leap;
+    strcpy(tz_orig, tz_env);
+  }
+  setenv("TZ", CNF_GetLeapSecTimezone(), 1);
+  tzset();
+
+  /* Get the TAI-UTC offset, which started at the epoch at 10 seconds */
+  t = mktime(&stm);
+  if (t != -1)
+    *tai_offset = t - when + 10;
+
+  /* Set the time to 23:59:60 and see how it overflows in mktime() */
+  stm.tm_sec = 60;
+  stm.tm_min = 59;
+  stm.tm_hour = 23;
+
+  t = mktime(&stm);
+
+  if (tz_env)
+    setenv("TZ", tz_orig, 1);
+  else
+    unsetenv("TZ");
+  tzset();
+
+  if (t == -1)
+    return tz_leap;
+
+  if (stm.tm_sec == 60)
+    tz_leap = LEAP_InsertSecond;
+  else if (stm.tm_sec == 1)
+    tz_leap = LEAP_DeleteSecond;
+
+  return tz_leap;
+}
+
+/* ================================================== */
+
+static NTP_Leap
+get_list_leap(time_t when, int *tai_offset)
+{
+  FILE *f;
+  char line[1024];
+  NTP_Leap ret_leap = LEAP_Normal;
+  int ret_tai_offset = 0, prev_lsl_tai_offset = 10;
+  int64_t when1900, lsl_updated = 0, lsl_expiry = 0;
+  const char *leap_sec_list = CNF_GetLeapSecList();
+
+  if (!(f = UTI_OpenFile(NULL, leap_sec_list, NULL, 'r', 0))) {
+    LOG(LOGS_ERR, "Failed to open leap seconds list %s", leap_sec_list);
+    goto out;
+  }
+
+  /* Leap second happens at midnight */
+  when = (when / (24 * 3600) + 1) * (24 * 3600);
+
+  /* leap-seconds.list timestamps are relative to 1 Jan 1900, 00:00:00 */
+  when1900 = (int64_t)when + LEAP_SEC_LIST_OFFSET;
+
+  while (fgets(line, sizeof line, f) > 0) {
+    int64_t lsl_when;
+    int lsl_tai_offset;
+    char *p;
+
+    /* Ignore blank lines */
+    for (p = line; *p && isspace(*p); ++p)
+      ;
+    if (!*p)
+      continue;
+
+    if (*line == '#') {
+      /* Update time line starts with #$ */
+      if (line[1] == '$' && sscanf(line + 2, "%"SCNd64, &lsl_updated) != 1)
+        goto error;
+      /* Expiration time line starts with #@ */
+      if (line[1] == '@' && sscanf(line + 2, "%"SCNd64, &lsl_expiry) != 1)
+        goto error;
+      /* Comment or a special comment we don't care about */
+      continue;
+    }
+
+    /* Leap entry */
+    if (sscanf(line, "%"SCNd64" %d", &lsl_when, &lsl_tai_offset) != 2)
+      goto error;
+
+    if (when1900 == lsl_when) {
+      if (lsl_tai_offset > prev_lsl_tai_offset)
+        ret_leap = LEAP_InsertSecond;
+      else if (lsl_tai_offset < prev_lsl_tai_offset)
+        ret_leap = LEAP_DeleteSecond;
+      /* When is rounded to the end of the day, so offset hasn't changed yet! */
+      ret_tai_offset = prev_lsl_tai_offset;
+    } else if (when1900 > lsl_when) {
+      ret_tai_offset = lsl_tai_offset;
+    }
+
+    prev_lsl_tai_offset = lsl_tai_offset;
+  }
+
+  /* Make sure the file looks sensible */
+  if (!feof(f) || !lsl_updated || !lsl_expiry)
+    goto error;
+
+  if (when1900 >= lsl_expiry)
+    LOG(LOGS_WARN, "Leap second list %s needs update", leap_sec_list);
+
+  goto out;
+
+error:
+  if (f)
+    fclose(f);
+  LOG(LOGS_ERR, "Failed to parse leap seconds list %s", leap_sec_list);
+  return LEAP_Normal;
+
+out:
+  if (f)
+    fclose(f);
+  *tai_offset = ret_tai_offset;
+  return ret_leap;
+}
+
+/* ================================================== */
+
+static int
+check_leap_source(NTP_Leap (*src)(time_t when, int *tai_offset))
+{
+  int tai_offset = 0;
+
+  /* Check that the leap second source has good data for Jun 30 2012 and Dec 31 2012 */
+  if (src(1341014400, &tai_offset) == LEAP_InsertSecond && tai_offset == 34 &&
+      src(1356912000, &tai_offset) == LEAP_Normal && tai_offset == 35)
+    return 1;
+
+  return 0;
+}
+
+/* ================================================== */
+
+void
+LDB_Initialise(void)
+{
+  const char *leap_tzname, *leap_sec_list;
+
+  leap_tzname = CNF_GetLeapSecTimezone();
+  if (leap_tzname && !check_leap_source(get_tz_leap)) {
+    LOG(LOGS_WARN, "Timezone %s failed leap second check, ignoring", leap_tzname);
+    leap_tzname = NULL;
+  }
+
+  leap_sec_list = CNF_GetLeapSecList();
+  if (leap_sec_list && !check_leap_source(get_list_leap)) {
+    LOG(LOGS_WARN, "Leap second list %s failed check, ignoring", leap_sec_list);
+    leap_sec_list = NULL;
+  }
+
+  if (leap_sec_list) {
+    LOG(LOGS_INFO, "Using leap second list %s", leap_sec_list);
+    leap_src = SRC_LIST;
+  } else if (leap_tzname) {
+    LOG(LOGS_INFO, "Using %s timezone to obtain leap second data", leap_tzname);
+    leap_src = SRC_TIMEZONE;
+  }
+}
+
+/* ================================================== */
+
+NTP_Leap
+LDB_GetLeap(time_t when, int *tai_offset)
+{
+  static time_t last_ldb_leap_check;
+  static NTP_Leap ldb_leap;
+  static int ldb_tai_offset;
+
+  /* Do this check at most twice a day */
+  when = when / (12 * 3600) * (12 * 3600);
+  if (last_ldb_leap_check == when)
+    goto out;
+
+  last_ldb_leap_check = when;
+  ldb_leap = LEAP_Normal;
+  ldb_tai_offset = 0;
+
+  switch (leap_src) {
+  case SRC_NONE:
+    break;
+  case SRC_TIMEZONE:
+    ldb_leap = get_tz_leap(when, &ldb_tai_offset);
+    break;
+  case SRC_LIST:
+    ldb_leap = get_list_leap(when, &ldb_tai_offset);
+    break;
+  }
+
+out:
+  *tai_offset = ldb_tai_offset;
+  return ldb_leap;
+}
+
+/* ================================================== */
+
+void
+LDB_Finalise(void)
+{
+  /* Nothing to do */
+}