lib/posixtm.c

   1 /* Parse dates for touch and date.
   2    Copyright (C) 1989, 1990, 1991, 1998, 2000-2003 Free Software Foundation Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Yacc-based version written by Jim Kingdon and David MacKenzie.
  19    Rewritten by Jim Meyering.  */
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include <stdbool.h>
  26
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <sys/types.h>
  30 #include <string.h>
  31
  32 #ifdef TM_IN_SYS_TIME
  33 # include <sys/time.h>
  34 #else
  35 # include <time.h>
  36 #endif
  37
  38 #include "posixtm.h"
  39 #include "unlocked-io.h"
  40
  41 /* ISDIGIT differs from isdigit, as follows:
  42    - Its arg may be any int or unsigned int; it need not be an unsigned char.
  43    - It's guaranteed to evaluate its argument exactly once.
  44    - It's typically faster.
  45    POSIX says that only '0' through '9' are digits.  Prefer ISDIGIT to
  46    ISDIGIT_LOCALE unless it's important to use the locale's definition
  47    of `digit' even when the host does not conform to POSIX.  */
  48 #define ISDIGIT(c) ((unsigned) (c) - '0' <= 9)
  49
  50 time_t mktime ();
  51
  52 /*
  53   POSIX requires:
  54
  55   touch -t [[CC]YY]mmddhhmm[.ss] FILE...
  56     8, 10, or 12 digits, followed by optional .ss
  57     (PDS_LEADING_YEAR | PDS_CENTURY | PDS_SECONDS)
  58
  59   touch mmddhhmm[YY] FILE... (obsoleted by POSIX 1003.1-2001)
  60     8 or 10 digits
  61     (PDS_TRAILING_YEAR)
  62
  63   date mmddhhmm[[CC]YY]
  64     8, 10, or 12 digits
  65     (PDS_TRAILING_YEAR | PDS_CENTURY)
  66
  67 */
  68
  69 static int
  70 year (struct tm *tm, const int *digit_pair, size_t n, int allow_century)
  71 {
  72   switch (n)
  73     {
  74     case 1:
  75       tm->tm_year = *digit_pair;
  76       /* Deduce the century based on the year.
  77          POSIX requires that 00-68 be interpreted as 2000-2068,
  78          and that 69-99 be interpreted as 1969-1999.  */
  79       if (digit_pair[0] <= 68)
  80         tm->tm_year += 100;
  81       break;
  82
  83     case 2:
  84       if (!allow_century)
  85         return 1;
  86       tm->tm_year = digit_pair[0] * 100 + digit_pair[1] - 1900;
  87       break;
  88
  89     case 0:
  90       {
  91         time_t now;
  92         struct tm *tmp;
  93
  94         /* Use current year.  */
  95         time (&now);
  96         tmp = localtime (&now);
  97         if (! tmp)
  98           return 1;
  99         tm->tm_year = tmp->tm_year;
 100       }
 101       break;
 102
 103     default:
 104       abort ();
 105     }
 106
 107   return 0;
 108 }
 109
 110 static int
 111 posix_time_parse (struct tm *tm, const char *s, unsigned int syntax_bits)
 112 {
 113   const char *dot = NULL;
 114   int pair[6];
 115   int *p;
 116   unsigned int i;
 117
 118   size_t s_len = strlen (s);
 119   size_t len = (((syntax_bits & PDS_SECONDS) && (dot = strchr (s, '.')))
 120                 ? (size_t) (dot - s)
 121                 : s_len);
 122
 123   if (len != 8 && len != 10 && len != 12)
 124     return 1;
 125
 126   if (dot)
 127     {
 128       if (!(syntax_bits & PDS_SECONDS))
 129         return 1;
 130
 131       if (s_len - len != 3)
 132         return 1;
 133     }
 134
 135   for (i = 0; i < len; i++)
 136     if (!ISDIGIT (s[i]))
 137       return 1;
 138
 139   len /= 2;
 140   for (i = 0; i < len; i++)
 141     pair[i] = 10 * (s[2*i] - '0') + s[2*i + 1] - '0';
 142
 143   p = pair;
 144   if (syntax_bits & PDS_LEADING_YEAR)
 145     {
 146       if (year (tm, p, len - 4, syntax_bits & PDS_CENTURY))
 147         return 1;
 148       p += len - 4;
 149       len = 4;
 150     }
 151
 152   /* Handle 8 digits worth of `MMDDhhmm'.  */
 153   tm->tm_mon = *p++ - 1;
 154   tm->tm_mday = *p++;
 155   tm->tm_hour = *p++;
 156   tm->tm_min = *p++;
 157   len -= 4;
 158
 159   /* Handle any trailing year.  */
 160   if (syntax_bits & PDS_TRAILING_YEAR)
 161     {
 162       if (year (tm, p, len, syntax_bits & PDS_CENTURY))
 163         return 1;
 164     }
 165
 166   /* Handle seconds.  */
 167   if (!dot)
 168     {
 169       tm->tm_sec = 0;
 170     }
 171   else
 172     {
 173       int seconds;
 174
 175       ++dot;
 176       if (!ISDIGIT (dot[0]) || !ISDIGIT (dot[1]))
 177         return 1;
 178       seconds = 10 * (dot[0] - '0') + dot[1] - '0';
 179
 180       tm->tm_sec = seconds;
 181     }
 182
 183   return 0;
 184 }
 185
 186 /* Parse a POSIX-style date, returning true if successful.  */
 187
 188 bool
 189 posixtime (time_t *p, const char *s, unsigned int syntax_bits)
 190 {
 191   struct tm tm0;
 192   struct tm tm1;
 193   struct tm const *tm;
 194   time_t t;
 195
 196   if (posix_time_parse (&tm0, s, syntax_bits))
 197     return false;
 198
 199   tm1 = tm0;
 200   tm1.tm_isdst = -1;
 201   t = mktime (&tm1);
 202
 203   if (t != (time_t) -1)
 204     tm = &tm1;
 205   else
 206     {
 207       /* mktime returns -1 for errors, but -1 is also a valid time_t
 208          value.  Check whether an error really occurred.  */
 209       tm = localtime (&t);
 210       if (! tm)
 211         return false;
 212     }
 213
 214   /* Reject dates like "September 31" and times like "25:61".  */
 215   if ((tm0.tm_year ^ tm->tm_year)
 216       | (tm0.tm_mon ^ tm->tm_mon)
 217       | (tm0.tm_mday ^ tm->tm_mday)
 218       | (tm0.tm_hour ^ tm->tm_hour)
 219       | (tm0.tm_min ^ tm->tm_min)
 220       | (tm0.tm_sec ^ tm->tm_sec))
 221     return false;
 222
 223   *p = t;
 224   return true;
 225 }
 226
 227 #ifdef TEST_POSIXTIME
 228 /*
 229     Test mainly with syntax_bits == 13
 230     (aka: (PDS_LEADING_YEAR | PDS_CENTURY | PDS_SECONDS))
 231
 232     This test data assumes Universal Time, e.g., TZ="UTC0".
 233
 234     This test data also assumes that time_t is signed and is at least
 235     39 bits wide, so that it can represent all years from 0000 through
 236     9999.  A host with 32-bit signed time_t can represent only time
 237     stamps in the range 1901-12-13 20:45:52 through 2038-01-18
 238     03:14:07 UTC, assuming POSIX time_t with no leap seconds, so test
 239     cases outside this range will not work on such a host.
 240
 241     Also, the first two lines of test data assume that the current
 242     year is 2002.
 243
 244 BEGIN-DATA
 245 12131415.16     13   1039788916 Fri Dec 13 14:15:16 2002
 246 12131415.16     13   1039788916 Fri Dec 13 14:15:16 2002
 247 000001010000.00 13 -62167132800 Sun Jan  1 00:00:00 0000
 248 190112132045.52 13  -2147483648 Fri Dec 13 20:45:52 1901
 249 190112132045.53 13  -2147483647 Fri Dec 13 20:45:53 1901
 250 190112132046.52 13  -2147483588 Fri Dec 13 20:46:52 1901
 251 190112132145.52 13  -2147480048 Fri Dec 13 21:45:52 1901
 252 190112142045.52 13  -2147397248 Sat Dec 14 20:45:52 1901
 253 190201132045.52 13  -2144805248 Mon Jan 13 20:45:52 1902
 254 196912312359.59 13           -1 Wed Dec 31 23:59:59 1969
 255 197001010000.00 13            0 Thu Jan  1 00:00:00 1970
 256 197001010000.01 13            1 Thu Jan  1 00:00:01 1970
 257 197001010001.00 13           60 Thu Jan  1 00:01:00 1970
 258 197001010100.00 13         3600 Thu Jan  1 01:00:00 1970
 259 197001020000.00 13        86400 Fri Jan  2 00:00:00 1970
 260 197002010000.00 13      2678400 Sun Feb  1 00:00:00 1970
 261 197101010000.00 13     31536000 Fri Jan  1 00:00:00 1971
 262 197001000000.00 13            * *
 263 197000010000.00 13            * *
 264 197001010000.60 13            * *
 265 197001010060.00 13            * *
 266 197001012400.00 13            * *
 267 197001320000.00 13            * *
 268 197013010000.00 13            * *
 269 203801190314.06 13   2147483646 Tue Jan 19 03:14:06 2038
 270 203801190314.07 13   2147483647 Tue Jan 19 03:14:07 2038
 271 203801190314.08 13   2147483648 Tue Jan 19 03:14:08 2038
 272 999912312359.59 13 253402300799 Fri Dec 31 23:59:59 9999
 273 1112131415      13   1323785700 Tue Dec 13 14:15:00 2011
 274 1112131415.16   13   1323785716 Tue Dec 13 14:15:16 2011
 275 201112131415.16 13   1323785716 Tue Dec 13 14:15:16 2011
 276 191112131415.16 13  -1831974284 Wed Dec 13 14:15:16 1911
 277 203712131415.16 13   2144326516 Sun Dec 13 14:15:16 2037
 278 3712131415.16   13   2144326516 Sun Dec 13 14:15:16 2037
 279 6812131415.16   13   3122633716 Thu Dec 13 14:15:16 2068
 280 6912131415.16   13     -1590284 Sat Dec 13 14:15:16 1969
 281 7012131415.16   13     29945716 Sun Dec 13 14:15:16 1970
 282 1213141599       2    945094500 Mon Dec 13 14:15:00 1999
 283 1213141500       2    976716900 Wed Dec 13 14:15:00 2000
 284 END-DATA
 285
 286 */
 287
 288 # define MAX_BUFF_LEN 1024
 289
 290 int
 291 main (void)
 292 {
 293   char buff[MAX_BUFF_LEN + 1];
 294
 295   buff[MAX_BUFF_LEN] = 0;
 296   while (fgets (buff, MAX_BUFF_LEN, stdin) && buff[0])
 297     {
 298       char time_str[MAX_BUFF_LEN];
 299       unsigned int syntax_bits;
 300       time_t t;
 301       if (sscanf (buff, "%s %u", time_str, &syntax_bits) != 2)
 302         printf ("*\n");
 303       else
 304         {
 305           printf ("%-15s %2u ", time_str, syntax_bits);
 306           if (posixtime (&t, time_str, syntax_bits))
 307             printf ("%12ld %s", (long) t, ctime (&t));
 308           else
 309             printf ("%12s %s", "*", "*\n");
 310         }
 311     }
 312   exit (0);
 313
 314 }
 315 #endif
 316 \f
 317 /*
 318 Local Variables:
 319 compile-command: "gcc -DTEST_POSIXTIME -DHAVE_CONFIG_H -I.. -g -O -Wall -W posixtm.c"
 320 End:
 321 */