Fix unlikely problems with time overflow

Also, fix some rounding errors while we’re in the neighborhood.
* src/buffer.c (duration_ns, compute_duration_ns): Rename from
‘duration’ and ‘compute_duration’, and count ns rather than s, to
lessen rounding error.  All uses changed.
(compute_duration_ns): Work even if the clock moves backward
and time_t is unsigned.
(print_stats): Don’t worry about null or empty TEXT, as that
cannot happen.  Compare double to UINTMAX_MAX + 1.0, not
to UINTMAX_MAX, so that the comparison is exact.
Handle the unlikely case that numbytes >= UINTMAX_MAX.
* src/tar.c (parse_opt): Treat -L hugenumber as effectively
infinity rather than erroring out.
Prefer ckd_add to checking overflow by hand.

src/buffer.c

@@ -249,7 +249,8 @@ clear_read_error_count (void)
 
 /* Time-related functions */
 
-static double duration;
+/* Time consumed during run.  It is counted in ns to lessen rounding error.  */
+static double duration_ns;
 
 void
 set_start_time (void)
@@ -267,14 +268,18 @@ set_volume_start_time (void)
 }
 
 double
-compute_duration (void)
+compute_duration_ns (void)
 {
-  struct timespec now;
-  gettime (&now);
-  duration += ((now.tv_sec - last_stat_time.tv_sec)
-               + (now.tv_nsec - last_stat_time.tv_nsec) / 1e9);
-  gettime (&last_stat_time);
-  return duration;
+  struct timespec now = current_timespec ();
+
+  /* If the clock moves back, treat it as duration 0.
+     This works even if time_t is unsigned.  */
+  if (timespec_cmp (last_stat_time, now) < 0)
+    duration_ns += (1e9 * (now.tv_sec - last_stat_time.tv_sec)
+		    + (now.tv_nsec - last_stat_time.tv_nsec));
+
+  last_stat_time = current_timespec ();
+  return duration_ns;
 }
 
 
@@ -491,19 +496,29 @@ static int
 print_stats (FILE *fp, const char *text, tarlong numbytes)
 {
   char abbr[LONGEST_HUMAN_READABLE + 1];
-  char rate[LONGEST_HUMAN_READABLE + 1];
-  int n = 0;
-
   int human_opts = human_autoscale | human_base_1024 | human_SI | human_B;
+  double ulim = UINTMAX_MAX + 1.0;
 
-  if (text && text[0])
-    n += fprintf (fp, "%s: ", gettext (text));
-  return n + fprintf (fp, TARLONG_FORMAT " (%s, %s/s)",
-		      numbytes,
-		      human_readable (numbytes, abbr, human_opts, 1, 1),
-		      (0 < duration && numbytes / duration < (uintmax_t) -1
-		       ? human_readable (numbytes / duration, rate, human_opts, 1, 1)
-		       : "?"));
+  int n = fprintf (fp, "%s: "TARLONG_FORMAT" (", gettext (text), numbytes);
+
+  if (numbytes < ulim)
+    n += fprintf (fp, "%s", human_readable (numbytes, abbr, human_opts, 1, 1));
+  else
+    n += fprintf (fp, "%g", numbytes);
+
+  if (!duration_ns)
+    n += fprintf (fp, ")");
+  else
+    {
+      double rate = 1e9 * numbytes / duration_ns;
+      if (rate < ulim)
+	n += fprintf (fp, ", %s/s)",
+		      human_readable (rate, abbr, human_opts, 1, 1));
+      else
+	n += fprintf (fp, ", %g/s)", rate);
+    }
+
+  return n;
 }
 
 /* Format totals to file FP.  FORMATS is an array of strings to output
@@ -1121,7 +1136,7 @@ close_archive (void)
       while (current_block > record_start);
     }
 
-  compute_duration ();
+  compute_duration_ns ();
   if (verify_option)
     verify_volume ();
 

src/checkpoint.c

@@ -291,14 +291,14 @@ format_checkpoint_string (FILE *fp, size_t len,
 	      break;
 
 	    case 'd':
-	      len += fprintf (fp, "%.0f", compute_duration ());
+	      len += fprintf (fp, "%.0f", compute_duration_ns () / BILLION);
 	      break;
 
 	    case 'T':
 	      {
 		const char **fmt = checkpoint_total_format, *fmtbuf[3];
 		struct wordsplit ws;
-		compute_duration ();
+		compute_duration_ns ();
 
 		if (arg)
 		  {
@@ -420,7 +420,7 @@ run_checkpoint_actions (bool do_write)
 	  break;
 
 	case cop_totals:
-	  compute_duration ();
+	  compute_duration_ns ();
 	  print_total_stats ();
 	  break;
 

src/common.h

@@ -455,7 +455,7 @@ size_t available_space_after (union block *pointer);
 off_t current_block_ordinal (void);
 void close_archive (void);
 void closeout_volume_number (void);
-double compute_duration (void);
+double compute_duration_ns (void);
 union block *find_next_block (void);
 void flush_read (void);
 void flush_write (void);

src/tar.c

@@ -1083,7 +1083,7 @@ set_use_compress_program_option (const char *string, struct option_locus *loc)
 static void
 sigstat (int signo)
 {
-  compute_duration ();
+  compute_duration_ns ();
   print_total_stats ();
 #ifndef HAVE_SIGACTION
   signal (signo, sigstat);
@@ -1688,13 +1688,24 @@ parse_opt (int key, char *arg, struct argp_state *state)
 	uintmax_t u;
 	char *p;
 
-	if (xstrtoumax (arg, &p, 10, &u, TAR_SIZE_SUFFIXES) != LONGINT_OK)
-	  USAGE_ERROR ((0, 0, "%s: %s", quotearg_colon (arg),
-			_("Invalid tape length")));
-	if (p > arg && !strchr (TAR_SIZE_SUFFIXES, p[-1]))
-	  tape_length_option = 1024 * (tarlong) u;
-	else
-	  tape_length_option = (tarlong) u;
+	switch (xstrtoumax (arg, &p, 10, &u, TAR_SIZE_SUFFIXES))
+	  {
+	  case LONGINT_OK:
+	    tape_length_option = u;
+	    if (arg < p && !strchr (TAR_SIZE_SUFFIXES, p[-1]))
+	      tape_length_option *= 1024;
+	    break;
+
+	  case LONGINT_OVERFLOW:
+	    /* Treat enormous values as effectively infinity.  */
+	    tape_length_option = 0;
+	    break;
+
+	  default:
+	    USAGE_ERROR ((0, 0, "%s: %s", quotearg_colon (arg),
+			  _("Invalid tape length")));
+	  }
+
 	multi_volume_option = true;
       }
       break;
@@ -2102,10 +2113,9 @@ parse_opt (int key, char *arg, struct argp_state *state)
 	uintmax_t u;
 
 	if (! (xstrtoumax (arg, NULL, 10, &u, TAR_SIZE_SUFFIXES) == LONGINT_OK
-	       && u == (size_t) u))
+	       && !ckd_add (&record_size, u, 0)))
 	  USAGE_ERROR ((0, 0, "%s: %s", quotearg_colon (arg),
 			_("Invalid record size")));
-	record_size = u;
 	if (record_size % BLOCKSIZE != 0)
 	  USAGE_ERROR ((0, 0, _("Record size must be a multiple of %d."),
 			BLOCKSIZE));
@@ -2151,10 +2161,9 @@ parse_opt (int key, char *arg, struct argp_state *state)
       {
 	uintmax_t u;
 	if (! (xstrtoumax (arg, 0, 10, &u, "") == LONGINT_OK
-	       && u == (size_t) u))
+	       && !ckd_add (&strip_name_components, u, 0)))
 	  USAGE_ERROR ((0, 0, "%s: %s", quotearg_colon (arg),
 			_("Invalid number of elements")));
-	strip_name_components = u;
       }
       break;