sources: improve handling of dump files and their format

Check for write errors when saving dump files. Don't save files with no
samples. Add more sanity checks for loaded data.

Extend the file format to include an identifier, the reachability
register, leap status, name, and authentication flag. Avoid loading
unauthenticated data after switching authentication on. Change format
and order of some fields to simplify parsing. Drop fields that were kept
only for compatibility.

The dump files now contain all information needed to perform the source
selection and update the reference.

There is no support kept for the old file format. Loading of old dump
files will fail after upgrading to new version.

sourcestats.c

@@ -852,38 +852,30 @@ SST_GetDelayTestData(SST_Stats inst, struct timespec *sample_time,
 /* This is used to save the register to a file, so that we can reload
    it after restarting the daemon */
 
-void
+int
 SST_SaveToFile(SST_Stats inst, FILE *out)
 {
   int m, i, j;
 
-  fprintf(out, "%d\n", inst->n_samples);
+  if (inst->n_samples < 1)
+    return 0;
+
+  if (fprintf(out, "%d %d\n", inst->n_samples, inst->asymmetry_run) < 0)
+    return 0;
 
   for(m = 0; m < inst->n_samples; m++) {
     i = get_runsbuf_index(inst, m);
     j = get_buf_index(inst, m);
 
-    fprintf(out,
-#ifdef HAVE_LONG_TIME_T
-            "%08"PRIx64" %08lx %.6e %.6e %.6e %.6e %.6e %.6e %.6e %d\n",
-            (uint64_t)inst->sample_times[i].tv_sec,
-#else
-            "%08lx %08lx %.6e %.6e %.6e %.6e %.6e %.6e %.6e %d\n",
-            (unsigned long)inst->sample_times[i].tv_sec,
-#endif
-            (unsigned long)inst->sample_times[i].tv_nsec / 1000,
-            inst->offsets[i],
-            inst->orig_offsets[j],
-            inst->peer_delays[i],
-            inst->peer_dispersions[j],
-            inst->root_delays[j],
-            inst->root_dispersions[j],
-            1.0, /* used to be inst->weights[i] */
-            0 /* used to be an array of strata */);
-
+    if (fprintf(out, "%s %.6e %.6e %.6e %.6e %.6e %.6e\n",
+                UTI_TimespecToString(&inst->sample_times[i]),
+                inst->offsets[i], inst->orig_offsets[j],
+                inst->peer_delays[i], inst->peer_dispersions[j],
+                inst->root_delays[j], inst->root_dispersions[j]) < 0)
+      return 0;
   }
 
-  fprintf(out, "%d\n", inst->asymmetry_run);
+  return 1;
 }
 
 /* ================================================== */
@@ -892,66 +884,32 @@ SST_SaveToFile(SST_Stats inst, FILE *out)
 int
 SST_LoadFromFile(SST_Stats inst, FILE *in)
 {
-#ifdef HAVE_LONG_TIME_T
-  uint64_t sec;
-#else
-  unsigned long sec;
-#endif
-  unsigned long usec;
-  int i;
-  char line[1024];
-  double weight;
-  int stratum;
+  int i, n_samples, arun;
+  double sample_time;
+  char line[256];
+
+  if (!fgets(line, sizeof (line), in) ||
+      sscanf(line, "%d %d", &n_samples, &arun) != 2 ||
+      n_samples < 1 || n_samples > MAX_SAMPLES)
+    return 0;
 
   SST_ResetInstance(inst);
 
-  if (fgets(line, sizeof(line), in) &&
-      sscanf(line, "%d", &inst->n_samples) == 1 &&
-      inst->n_samples >= 0 && inst->n_samples <= MAX_SAMPLES) {
+  for (i = 0; i < n_samples; i++) {
+    if (!fgets(line, sizeof (line), in) ||
+        sscanf(line, "%lf %lf %lf %lf %lf %lf %lf",
+               &sample_time, &inst->offsets[i], &inst->orig_offsets[i],
+               &inst->peer_delays[i], &inst->peer_dispersions[i],
+               &inst->root_delays[i], &inst->root_dispersions[i]) != 7)
+      return 0;
 
-    for (i=0; i<inst->n_samples; i++) {
-      if (!fgets(line, sizeof(line), in) ||
-          (sscanf(line,
-#ifdef HAVE_LONG_TIME_T
-                  "%"SCNx64"%lx%lf%lf%lf%lf%lf%lf%lf%d\n",
-#else
-                  "%lx%lx%lf%lf%lf%lf%lf%lf%lf%d\n",
-#endif
-                  &(sec), &(usec),
-                  &(inst->offsets[i]),
-                  &(inst->orig_offsets[i]),
-                  &(inst->peer_delays[i]),
-                  &(inst->peer_dispersions[i]),
-                  &(inst->root_delays[i]),
-                  &(inst->root_dispersions[i]),
-                  &weight, /* not used anymore */
-                  &stratum /* not used anymore */) != 10)) {
-
-        /* This is the branch taken if the read FAILED */
-
-        inst->n_samples = 0; /* Load abandoned if any sign of corruption */
-        return 0;
-      } else {
-
-        /* This is the branch taken if the read is SUCCESSFUL */
-        inst->sample_times[i].tv_sec = sec;
-        inst->sample_times[i].tv_nsec = 1000 * usec;
-        UTI_NormaliseTimespec(&inst->sample_times[i]);
-      }
-    }
-
-    /* This field was not saved in older versions */
-    if (!fgets(line, sizeof(line), in) || sscanf(line, "%d\n", &inst->asymmetry_run) != 1)
-      inst->asymmetry_run = 0;
-  } else {
-    inst->n_samples = 0; /* Load abandoned if any sign of corruption */
-    return 0;
+    /* Some resolution is lost in the double format, but that's ok */
+    UTI_DoubleToTimespec(sample_time, &inst->sample_times[i]);
   }
 
-  if (!inst->n_samples)
-    return 1;
-
+  inst->n_samples = n_samples;
   inst->last_sample = inst->n_samples - 1;
+  inst->asymmetry_run = CLAMP(-MAX_ASYMMETRY_RUN, arun, MAX_ASYMMETRY_RUN);
 
   find_min_delay_sample(inst);
   SST_DoNewRegression(inst);