Todd C. Miller is not on the time zone mailing list; direct replies appropriately. --ado -----Original Message----- From: Todd C. Miller [mailto:Todd.Miller@courtesan.com] Sent: Monday, August 08, 2005 11:29 PM To: tz@lecserver.nci.nih.gov Subject: bug introduced in tzcode2005c A change in tzcode 2005c causes the following program on OpenBSD to loop forever. I've tracked it down to the change included at the end of this message. Previously:: $ ./mktime Timestamp is: -1 Date is: Thu Jan 1 00:59:59 1970 With tzcode 2005c and beyond it loops forever. #include <sys/types.h> #include <stdio.h> #include <time.h> #include <stdlib.h> /* * This small programm will consume 100% CPU and loops forever with * tzcode 2005c - 2005k. */ int main(int argc, char **argv) { time_t timet; struct tm tm; tm.tm_sec = 36; tm.tm_min = 5; tm.tm_hour = 23; tm.tm_mday = 31; tm.tm_mon = 11; tm.tm_year = 138; /* 2038 - 1900 */ tm.tm_isdst = 0; timet = mktime(&tm); printf("Timestamp is: %d\n", timet); printf("Date is: %s\n", ctime(&timet)); exit(0); } Here's the change that triggers it. --- tzcode2005b/localtime.c Mon Jan 10 07:19:41 2005 +++ tzcode2005c/localtime.c Mon Jan 17 16:36:15 2005 @@ -1441,10 +1436,11 @@ { register const struct state * sp; register int dir; - register int bits; register int i, j; register int saved_seconds; register long li; + register time_t lo; + register time_t hi; long y; time_t newt; time_t t; @@ -1518,28 +1514,49 @@ yourtm.tm_sec = 0; } /* - ** Divide the search space in half - ** (this works whether time_t is signed or unsigned). + ** Do a binary search (this works whatever time_t's type is). */ - bits = TYPE_BIT(time_t) - 1; - /* - ** If time_t is signed, then 0 is just above the median, - ** assuming two's complement arithmetic. - ** If time_t is unsigned, then (1 << bits) is just above the median. - */ - t = TYPE_SIGNED(time_t) ? 0 : (((unsigned long) 1) << bits); + if (!TYPE_SIGNED(time_t)) { + lo = 0; + hi = lo - 1; + } else if (!TYPE_INTEGRAL(time_t)) { + if (sizeof(time_t) > sizeof(float)) + hi = (time_t) DBL_MAX; + else hi = (time_t) FLT_MAX; + lo = -hi; + } else { + lo = 1; + for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i) + lo *= 2; + hi = -(lo + 1); + } for ( ; ; ) { - if ((*funcp)(&t, offset, &mytm) == NULL) - return WRONG; /* XXX probably wrong */ - dir = tmcomp(&mytm, &yourtm); + t = lo / 2 + hi / 2; + if (t < lo) + t = lo; + else if (t > hi) + t = hi; + if ((*funcp)(&t, offset, &mytm) == NULL) { + /* + ** Assume that t is too extreme to be represented in + ** a struct tm; arrange things so that it is less + ** extreme on the next pass. + */ + dir = (t > 0) ? 1 : -1; + } else dir = tmcomp(&mytm, &yourtm); if (dir != 0) { - if (bits-- < 0) + if (t == lo) { + ++t; + ++lo; + } else if (t == hi) { + --t; + --hi; + } + if (lo > hi) return WRONG; - if (bits < 0) - --t; /* may be needed if new t is minimal */ - else if (dir > 0) - t -= ((long) 1) << bits; - else t += ((long) 1) << bits; + if (dir > 0) + hi = t; + else lo = t; continue; } if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)