y2038 time checks have overflow checks. Added documentation and

test programs in Porting/

p4raw-id: //depot/perl@34504

1 files changed, 148 insertions, 0 deletions

diff --git a/Porting/timecheck.c b/Porting/timecheck.c
new file mode 100644
index 0000000000..07f5872756
--- /dev/null
+++ b/Porting/timecheck.c
@@ -0,0 +1,148 @@
+#include <sys/types.h>
+#include <stdio.h>
+#include <time.h>
+#include <errno.h>
+#include <values.h>
+
+int opt_v = 0;
+int i;
+struct tm *tmp;
+time_t pt, pt_max, pt_min;
+
+static char hexbuf[80];
+char *hex (time_t t)
+{
+    if ((long long)t < 0)
+	sprintf (hexbuf, " -0x%016lx", -t);
+    else
+	sprintf (hexbuf, "  0x%016lx",  t);
+    return (hexbuf);
+    } /* hex */
+
+void gm_check (time_t t, int min_year, int max_year)
+{
+    tmp = gmtime (&t);
+    if ( tmp == NULL ||
+	/* Check tm_year overflow */
+	 tmp->tm_year < min_year || tmp->tm_year > max_year) {
+	if (opt_v)
+	    fprintf (stderr, "gmtime (%ld) failed with errno %d\n", t, errno);
+	}
+    else {
+	if (opt_v)
+	    fprintf (stderr, "%3d:%s: %12ld-%02d-%02d %02d:%02d:%02d\n",
+		i, hex (t),
+		tmp->tm_year + 1900, tmp->tm_mon + 1, tmp->tm_mday,
+		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+	pt = t;
+	}
+    } /* gm_check */
+
+int check_gm_max ()
+{
+    tmp = NULL;
+    pt  = 0;
+    if (tmp == NULL || tmp->tm_year < 0) {
+	for (i = 63; i >= 0; i--) {
+	    time_t x = pt | ((time_t)1 << i);
+	    if (x < 0 || x < pt) continue;
+	    gm_check (x, 69, 0x7fffffff);
+	    }
+	}
+    pt_max = pt;
+    return (0);
+    } /* check_gm_max */
+
+int check_gm_min ()
+{
+    tmp = NULL;
+    pt  = 0;
+    if (tmp == NULL) {
+	for (i = 36; i >= 0; i--) {
+	    time_t x = pt - ((time_t)1 << i);
+	    if (x > 0) continue;
+	    gm_check (x, -1900, 70);
+	    }
+	}
+    pt_min = pt;
+    return (0);
+    } /* check_gm_min */
+
+void lt_check (time_t t, int min_year, int max_year)
+{
+    if (sizeof (time_t) > 4 && t > 0x7ffffffffffff000LL)
+	tmp = NULL;
+    else
+	tmp = localtime (&t);
+    if ( tmp == NULL ||
+	/* Check tm_year overflow */
+	 tmp->tm_year < min_year || tmp->tm_year > max_year) {
+	if (opt_v)
+	    fprintf (stderr, "localtime (%ld) failed with errno %d\n", t, errno);
+	}
+    else {
+	if (opt_v)
+	    fprintf (stderr, "%3d:%s: %12ld-%02d-%02d %02d:%02d:%02d\n",
+		i, hex (t),
+		tmp->tm_year + 1900, tmp->tm_mon + 1, tmp->tm_mday,
+		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+	pt = t;
+	}
+    } /* lt_check */
+
+int check_lt_max ()
+{
+    tmp = NULL;
+    pt  = 0;
+    if (tmp == NULL || tmp->tm_year < 0) {
+	for (i = 63; i >= 0; i--) {
+	    time_t x = pt | ((time_t)1 << i);
+	    if (x < 0 || x < pt) continue;
+	    lt_check (x, 69, 0x7fffffff);
+	    }
+	}
+    pt_max = pt;
+    return (0);
+    } /* check_lt_max */
+
+int check_lt_min ()
+{
+    tmp = NULL;
+    pt  = 0;
+    if (tmp == NULL) {
+	for (i = 36; i >= 0; i--) {
+	    time_t x = pt - ((time_t)1 << i);
+	    if (x > 0) continue;
+	    lt_check (x, -1900, 70);
+	    }
+	}
+    pt_min = pt;
+    return (0);
+    } /* check_lt_min */
+
+int main (int argc, char *argv[])
+{
+    time_t gm_max, gm_min, lt_max, lt_min;
+    if (argc > 1 && strcmp (argv[1], "-v") == 0) opt_v++;
+
+    check_gm_max (); gm_max = pt_max;
+    check_gm_min (); gm_min = pt_min;
+    check_lt_max (); lt_max = pt_max;
+    check_lt_min (); lt_min = pt_min;
+
+    opt_v++;
+    printf ("======================\n");
+    printf ("Sizeof time_t = %ld\n", (i = sizeof (time_t)));
+    printf ("gmtime () boundaries:\n");
+    gm_check (gm_max,    69, 0x7fffffff);
+    gm_check (gm_min, -1900,         70);
+    printf ("localtime () boundaries:\n");
+    lt_check (lt_max,    69, 0x7fffffff);
+    lt_check (lt_min, -1900,         70);
+    printf ("Configure variables:\n");
+    printf ("sGMTIME_max='%ld'\n",    gm_max);
+    printf ("sGMTIME_min='%ld'\n",    gm_min);
+    printf ("sLOCALTIME_max='%ld'\n", lt_max);
+    printf ("sLOCALTIME_min='%ld'\n", lt_min);
+    return (0);
+    } /* main */