From: oetiker <oetiker@a5681a0c-68f1-0310-ab6d-d61299d08faa>
Date: Thu, 11 Nov 2010 16:06:55 +0000 (+0000)
Subject: Here is a patch that fixes a serious endless loop problem on 32 bit
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=9c9cf60a757fbbd2846d2a71473c2c42cdabdaa4;p=rrdtool.git

Here is a patch that fixes a serious endless loop problem on 32 bit
architectures near the timestamp 2^31 (oh yes - y2k038 is showing its ugly
face) when using the graph command(s). Once the endtime of a graph is
above the mentioned timestamp, mktime always returns -1 (and correctly
so), causing some loops to loop forever. The patch fixes this, causing
some strange output, but there is no other sane way to handle this (expect
by switching to a 64 bit platform). -- Peter Stamfest



git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk/program@2146 a5681a0c-68f1-0310-ab6d-d61299d08faa
---

diff --git a/src/rrd_graph.c b/src/rrd_graph.c
index d902a93..b101b32 100644
--- a/src/rrd_graph.c
+++ b/src/rrd_graph.c
@@ -1470,6 +1470,13 @@ time_t find_next_time(
 
     localtime_r(&current, &tm);
 
+    int limit = 2;
+    switch (baseint) {
+    case TMT_SECOND: limit = 7200; break;
+    case TMT_MINUTE: limit = 120; break;
+    case TMT_HOUR: limit = 2; break;
+    default: limit = 2; break;
+    }
     do {
         switch (baseint) {
         case TMT_SECOND:
@@ -1500,7 +1507,7 @@ time_t find_next_time(
             tm.       tm_year += basestep;
         }
         madetime = mktime(&tm);
-    } while (madetime == -1);   /* this is necessary to skip impssible times
+    } while (madetime == -1 && limit-- >= 0);   /* this is necessary to skip impossible times
                                    like the daylight saving time skips */
     return madetime;
 
@@ -2506,19 +2513,20 @@ void vertical_grid(
                              mgridtm,
                              im->xlab_user.
                              mgridst);
-             ti < im->end;
+             ti < im->end && ti != -1;
              ti =
              find_next_time(ti, im->xlab_user.gridtm, im->xlab_user.gridst)
             ) {
             /* are we inside the graph ? */
             if (ti < im->start || ti > im->end)
                 continue;
-            while (timajor < ti) {
+            while (timajor < ti && timajor != -1) {
                 timajor = find_next_time(timajor,
                                          im->
                                          xlab_user.
                                          mgridtm, im->xlab_user.mgridst);
             }
+            if (timajor == -1) break; /* fail in case of problems with time increments */
             if (ti == timajor)
                 continue;   /* skip as falls on major grid line */
             X0 = xtr(im, ti);
@@ -2542,7 +2550,7 @@ void vertical_grid(
                               im->
                               xlab_user.
                               mgridst);
-         ti < im->end;
+         ti < im->end && ti != -1;
          ti = find_next_time(ti, im->xlab_user.mgridtm, im->xlab_user.mgridst)
         ) {
         /* are we inside the graph ? */
@@ -2568,9 +2576,9 @@ void vertical_grid(
                          labtm,
                          im->xlab_user.
                          labst);
-         ti <=
+         (ti <=
          im->end -
-         im->xlab_user.precis / 2;
+         im->xlab_user.precis / 2) && ti != -1;
          ti = find_next_time(ti, im->xlab_user.labtm, im->xlab_user.labst)
         ) {
         tilab = ti + im->xlab_user.precis / 2;  /* correct time for the label */