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Fix unlikely problems with time overflow

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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.
This commit is contained in:
Paul Eggert
2024-08-01 10:02:06 -07:00
parent aae99e863d
commit 6c91bd82e1
4 changed files with 60 additions and 36 deletions
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55
src/buffer.c
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@@ -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 ();