Proposed Patch for zdump seg fault.

[Sachin Sant]

I came across a problem with zdump utility on a 64 bit systems. When one
uses the 
command " zdump -v GMT " , segmentation fault occurs. 

Since on a 64 bit system long is 8 bytes a call to __offtime( ) use to
fail 
because of integer overflow [ int being 4 bytes ]. 

This is a proposed patch to fix the problem. Let me know if its ok


Thanks
-Sachin

-------------------------------------------------------------------------------

--- zdump.c     2003-09-23 20:32:41.000000000 +0530
+++ zdump.c.new 2003-09-30 16:20:34.000000000 +0530
@@ -134,6 +134,18 @@ static size_t      longest;
 static char *  progname;
 static void    show P((char * zone, time_t t, int v));
 
+/* 
+ * On a 64 bit system zdump use to code dump when given the following
+ * command " zdump -v GMT ".
+ * The reason being __offtime( ) function call use to fail because 
+ * of overflow of integer value.
+ * A check on hibit is made so that it does not cross the minimum
+ * and maximum value a integer can hold. The below two defines are
+ * used to check the boundary conditions.
+ */
+#define CHKVALUE (1 << ((8 * sizeof(int)) - 1)) /* Minimum int value */
+#define CHKVALUE2 2147483647                    /* Maximum int value
*/   
+
 int
 main(argc, argv)
 int    argc;
@@ -224,6 +236,11 @@ _("%s: usage is %s [ -v ] [ -c cutoff ] 
                /*
                ** Get lowest value of t.
                */
+               /*
+               ** Check if hibit cross the minimum int value. 
+               */
+               if (hibit < CHKVALUE)
+                       hibit = CHKVALUE;
                t = hibit;
                if (t > 0)              /* time_t is unsigned */
                        t = 0;
@@ -236,6 +253,14 @@ _("%s: usage is %s [ -v ] [ -c cutoff ] 
                        if (cutoff != NULL && t >= cuttime)
                                break;
                        newt = t + SECSPERHOUR * 12;
+                       /*
+                        * A check was added so that newt would not
+                        * exceed maximum value integer can hold.
+                        * If it exceeds the value convert it to
+                        * proper negative value.
+                        */
+                       if (newt >= CHKVALUE2)
+                               newt = CHKVALUE2 - newt;
                        if (cutoff != NULL && newt >= cuttime) 
                                break;
                        if (newt <= t)