1 /* 2 * Copyright (c) 1987, 1989 Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Arthur David Olson of the National Cancer Institute. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. */ 35 36 /*static char *sccsid = "from: @(#)ctime.c 5.26 (Berkeley) 2/23/91";*/ 37 38 /* 39 * This implementation of mktime is lifted straight from the NetBSD (BSD 4.4) 40 * version. I modified it slightly to divorce it from the internals of the 41 * ctime library. Thus this version can't use details of the internal 42 * timezone state file to figure out strange unnormalized struct tm values, 43 * as might result from someone doing date math on the tm struct then passing 44 * it to mktime. 45 * 46 * It just does as well as it can at normalizing the tm input, then does a 47 * binary search of the time space using the system's localtime() function. 48 * 49 * The original binary search was defective in that it didn't consider the 50 * setting of tm_isdst when comparing tm values, causing the search to be 51 * flubbed for times near the dst/standard time changeover. The original 52 * code seems to make up for this by grubbing through the timezone info 53 * whenever the binary search barfed. Since I don't have that luxury in 54 * portable code, I have to take care of tm_isdst in the comparison routine. 55 * This requires knowing how many minutes offset dst is from standard time. 56 * 57 * So, if you live somewhere in the world where dst is not 60 minutes offset, 58 * and your vendor doesn't supply mktime(), you'll have to edit this variable 59 * by hand. Sorry about that. 60 */ 61 62 #include "ntp_machine.h" 63 64 #if !defined(HAVE_MKTIME) || !defined(HAVE_TIMEGM) 65 66 #ifndef DSTMINUTES 67 #define DSTMINUTES 60 68 #endif 69 70 #define FALSE 0 71 #define TRUE 1 72 73 /* some constants from tzfile.h */ 74 #define SECSPERMIN 60 75 #define MINSPERHOUR 60 76 #define HOURSPERDAY 24 77 #define DAYSPERWEEK 7 78 #define DAYSPERNYEAR 365 79 #define DAYSPERLYEAR 366 80 #define SECSPERHOUR (SECSPERMIN * MINSPERHOUR) 81 #define SECSPERDAY ((long) SECSPERHOUR * HOURSPERDAY) 82 #define MONSPERYEAR 12 83 #define TM_YEAR_BASE 1900 84 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0) 85 86 static int mon_lengths[2][MONSPERYEAR] = { 87 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }, 88 { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 } 89 }; 90 91 static int year_lengths[2] = { 92 DAYSPERNYEAR, DAYSPERLYEAR 93 }; 94 95 /* 96 ** Adapted from code provided by Robert Elz, who writes: 97 ** The "best" way to do mktime I think is based on an idea of Bob 98 ** Kridle's (so its said...) from a long time ago. (mtxinu!kridle now). 99 ** It does a binary search of the time_t space. Since time_t's are 100 ** just 32 bits, its a max of 32 iterations (even at 64 bits it 101 ** would still be very reasonable). 102 */ 103 104 #ifndef WRONG 105 #define WRONG (-1) 106 #endif /* !defined WRONG */ 107 108 static void 109 normalize( 110 int * tensptr, 111 int * unitsptr, 112 int base 113 ) 114 { 115 if (*unitsptr >= base) { 116 *tensptr += *unitsptr / base; 117 *unitsptr %= base; 118 } else if (*unitsptr < 0) { 119 --*tensptr; 120 *unitsptr += base; 121 if (*unitsptr < 0) { 122 *tensptr -= 1 + (-*unitsptr) / base; 123 *unitsptr = base - (-*unitsptr) % base; 124 } 125 } 126 } 127 128 static struct tm * 129 mkdst( 130 struct tm * tmp 131 ) 132 { 133 /* jds */ 134 static struct tm tmbuf; 135 136 tmbuf = *tmp; 137 tmbuf.tm_isdst = 1; 138 tmbuf.tm_min += DSTMINUTES; 139 normalize(&tmbuf.tm_hour, &tmbuf.tm_min, MINSPERHOUR); 140 return &tmbuf; 141 } 142 143 static int 144 tmcomp( 145 register struct tm * atmp, 146 register struct tm * btmp 147 ) 148 { 149 register int result; 150 151 /* compare down to the same day */ 152 153 if ((result = (atmp->tm_year - btmp->tm_year)) == 0 && 154 (result = (atmp->tm_mon - btmp->tm_mon)) == 0) 155 result = (atmp->tm_mday - btmp->tm_mday); 156 157 if(result != 0) 158 return result; 159 160 /* get rid of one-sided dst bias */ 161 162 if(atmp->tm_isdst == 1 && !btmp->tm_isdst) 163 btmp = mkdst(btmp); 164 else if(btmp->tm_isdst == 1 && !atmp->tm_isdst) 165 atmp = mkdst(atmp); 166 167 /* compare the rest of the way */ 168 169 if ((result = (atmp->tm_hour - btmp->tm_hour)) == 0 && 170 (result = (atmp->tm_min - btmp->tm_min)) == 0) 171 result = atmp->tm_sec - btmp->tm_sec; 172 return result; 173 } 174 175 176 static time_t 177 time2( 178 struct tm * tmp, 179 int * okayp, 180 int usezn 181 ) 182 { 183 register int dir; 184 register int bits; 185 register int i; 186 register int saved_seconds; 187 time_t t; 188 struct tm yourtm, mytm; 189 190 *okayp = FALSE; 191 yourtm = *tmp; 192 if (yourtm.tm_sec >= SECSPERMIN + 2 || yourtm.tm_sec < 0) 193 normalize(&yourtm.tm_min, &yourtm.tm_sec, SECSPERMIN); 194 normalize(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR); 195 normalize(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY); 196 normalize(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR); 197 while (yourtm.tm_mday <= 0) { 198 --yourtm.tm_year; 199 yourtm.tm_mday += 200 year_lengths[isleap(yourtm.tm_year + TM_YEAR_BASE)]; 201 } 202 for ( ; ; ) { 203 i = mon_lengths[isleap(yourtm.tm_year + 204 TM_YEAR_BASE)][yourtm.tm_mon]; 205 if (yourtm.tm_mday <= i) 206 break; 207 yourtm.tm_mday -= i; 208 if (++yourtm.tm_mon >= MONSPERYEAR) { 209 yourtm.tm_mon = 0; 210 ++yourtm.tm_year; 211 } 212 } 213 saved_seconds = yourtm.tm_sec; 214 yourtm.tm_sec = 0; 215 /* 216 ** Calculate the number of magnitude bits in a time_t 217 ** (this works regardless of whether time_t is 218 ** signed or unsigned, though lint complains if unsigned). 219 */ 220 for (bits = 0, t = 1; t > 0; ++bits, t <<= 1) 221 ; 222 /* 223 ** If time_t is signed, then 0 is the median value, 224 ** if time_t is unsigned, then 1 << bits is median. 225 */ 226 t = (t < 0) ? 0 : ((time_t) 1 << bits); 227 for ( ; ; ) { 228 if (usezn) 229 mytm = *localtime(&t); 230 else 231 mytm = *gmtime(&t); 232 dir = tmcomp(&mytm, &yourtm); 233 if (dir != 0) { 234 if (bits-- < 0) 235 return WRONG; 236 if (bits < 0) 237 --t; 238 else if (dir > 0) 239 t -= (time_t) 1 << bits; 240 else t += (time_t) 1 << bits; 241 continue; 242 } 243 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst) 244 break; 245 246 return WRONG; 247 } 248 t += saved_seconds; 249 if (usezn) 250 *tmp = *localtime(&t); 251 else 252 *tmp = *gmtime(&t); 253 *okayp = TRUE; 254 return t; 255 } 256 #else 257 int mktime_bs; 258 #endif /* !HAVE_MKTIME || !HAVE_TIMEGM */ 259 260 #ifndef HAVE_MKTIME 261 static time_t 262 time1( 263 struct tm * tmp 264 ) 265 { 266 register time_t t; 267 int okay; 268 269 if (tmp->tm_isdst > 1) 270 tmp->tm_isdst = 1; 271 t = time2(tmp, &okay, 1); 272 if (okay || tmp->tm_isdst < 0) 273 return t; 274 275 return WRONG; 276 } 277 278 time_t 279 mktime( 280 struct tm * tmp 281 ) 282 { 283 return time1(tmp); 284 } 285 #endif /* !HAVE_MKTIME */ 286 287 #ifndef HAVE_TIMEGM 288 time_t 289 timegm( 290 struct tm * tmp 291 ) 292 { 293 register time_t t; 294 int okay; 295 296 tmp->tm_isdst = 0; 297 t = time2(tmp, &okay, 0); 298 if (okay || tmp->tm_isdst < 0) 299 return t; 300 301 return WRONG; 302 } 303 #endif /* !HAVE_TIMEGM */ 304