coreutils/date.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini date implementation for busybox
   4  *
   5  * by Matthew Grant <grantma@anathoth.gen.nz>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  *
  21 */
  22
  23 #include "internal.h"
  24 #define BB_DECLARE_EXTERN
  25 #define bb_need_invalid_date
  26 #define bb_need_memory_exhausted
  27 #include "messages.c"
  28 #include <stdlib.h>
  29 #include <errno.h>
  30 #include <sys/time.h>
  31 #include <unistd.h>
  32 #include <time.h>
  33 #include <stdio.h>
  34
  35
  36 /* This 'date' command supports only 2 time setting formats,
  37    all the GNU strftime stuff (its in libc, lets use it),
  38    setting time using UTC and displaying int, as well as
  39    an RFC 822 complient date output for shell scripting
  40    mail commands */
  41
  42 static const char date_usage[] = "date [OPTION]... [+FORMAT]\n"
  43         "  or:  date [OPTION] [MMDDhhmm[[CC]YY][.ss]]\n"
  44 #ifndef BB_FEATURE_TRIVIAL_HELP
  45         "\nDisplays the current time in the given FORMAT, or sets the system date.\n"
  46         "\nOptions:\n\t-R\tOutputs RFC-822 compliant date string\n"
  47         "\t-s\tSets time described by STRING\n"
  48         "\t-u\tPrints or sets Coordinated Universal Time\n"
  49 #endif
  50         ;
  51
  52
  53 /* Input parsing code is always bulky - used heavy duty libc stuff as
  54    much as possible, missed out a lot of bounds checking */
  55
  56 /* Default input handling to save suprising some people */
  57
  58 struct tm *date_conv_time(struct tm *tm_time, const char *t_string)
  59 {
  60         int nr;
  61
  62         nr = sscanf(t_string, "%2d%2d%2d%2d%d",
  63                                 &(tm_time->tm_mon),
  64                                 &(tm_time->tm_mday),
  65                                 &(tm_time->tm_hour),
  66                                 &(tm_time->tm_min), &(tm_time->tm_year));
  67
  68         if (nr < 4 || nr > 5) {
  69                 fatalError(invalid_date, "date", t_string);
  70         }
  71
  72         /* correct for century  - minor Y2K problem here? */
  73         if (tm_time->tm_year >= 1900)
  74                 tm_time->tm_year -= 1900;
  75         /* adjust date */
  76         tm_time->tm_mon -= 1;
  77
  78         return (tm_time);
  79
  80 }
  81
  82
  83 /* The new stuff for LRP */
  84
  85 struct tm *date_conv_ftime(struct tm *tm_time, const char *t_string)
  86 {
  87         struct tm itm_time, jtm_time, ktm_time, ltm_time, mtm_time, ntm_time;
  88
  89         itm_time = *tm_time;
  90         jtm_time = *tm_time;
  91         ktm_time = *tm_time;
  92         ltm_time = *tm_time;
  93         mtm_time = *tm_time;
  94         ntm_time = *tm_time;
  95
  96         /* Parse input and assign appropriately to tm_time */
  97
  98         if (sscanf(t_string, "%d:%d:%d",
  99                            &itm_time.tm_hour, &itm_time.tm_min, &itm_time.tm_sec) == 3) {
 100
 101                 *tm_time = itm_time;
 102                 return (tm_time);
 103
 104         } else if (sscanf(t_string, "%d:%d",
 105                                           &jtm_time.tm_hour, &jtm_time.tm_min) == 2) {
 106
 107                 *tm_time = jtm_time;
 108                 return (tm_time);
 109
 110         } else if (sscanf(t_string, "%d.%d-%d:%d:%d",
 111                                           &ktm_time.tm_mon,
 112                                           &ktm_time.tm_mday,
 113                                           &ktm_time.tm_hour,
 114                                           &ktm_time.tm_min, &ktm_time.tm_sec) == 5) {
 115
 116                 ktm_time.tm_mon -= 1;   /* Adjust dates from 1-12 to 0-11 */
 117                 *tm_time = ktm_time;
 118                 return (tm_time);
 119
 120         } else if (sscanf(t_string, "%d.%d-%d:%d",
 121                                           &ltm_time.tm_mon,
 122                                           &ltm_time.tm_mday,
 123                                           &ltm_time.tm_hour, &ltm_time.tm_min) == 4) {
 124
 125                 ltm_time.tm_mon -= 1;   /* Adjust dates from 1-12 to 0-11 */
 126                 *tm_time = ltm_time;
 127                 return (tm_time);
 128
 129         } else if (sscanf(t_string, "%d.%d.%d-%d:%d:%d",
 130                                           &mtm_time.tm_year,
 131                                           &mtm_time.tm_mon,
 132                                           &mtm_time.tm_mday,
 133                                           &mtm_time.tm_hour,
 134                                           &mtm_time.tm_min, &mtm_time.tm_sec) == 6) {
 135
 136                 mtm_time.tm_year -= 1900;       /* Adjust years */
 137                 mtm_time.tm_mon -= 1;   /* Adjust dates from 1-12 to 0-11 */
 138                 *tm_time = mtm_time;
 139                 return (tm_time);
 140
 141         } else if (sscanf(t_string, "%d.%d.%d-%d:%d",
 142                                           &ntm_time.tm_year,
 143                                           &ntm_time.tm_mon,
 144                                           &ntm_time.tm_mday,
 145                                           &ntm_time.tm_hour, &ntm_time.tm_min) == 5) {
 146                 ntm_time.tm_year -= 1900;       /* Adjust years */
 147                 ntm_time.tm_mon -= 1;   /* Adjust dates from 1-12 to 0-11 */
 148                 *tm_time = ntm_time;
 149                 return (tm_time);
 150
 151         }
 152
 153         fatalError(invalid_date, "date", t_string);
 154 }
 155
 156
 157 int date_main(int argc, char **argv)
 158 {
 159         char *date_str = NULL;
 160         char *date_fmt = NULL;
 161         char *t_buff;
 162         int i;
 163         int set_time = 0;
 164         int rfc822 = 0;
 165         int utc = 0;
 166         int use_arg = 0;
 167         time_t tm;
 168         struct tm tm_time;
 169
 170         /* Interpret command line args */
 171         i = --argc;
 172         argv++;
 173         while (i > 0 && **argv) {
 174                 if (**argv == '-') {
 175                         while (i > 0 && *++(*argv))
 176                                 switch (**argv) {
 177                                 case 'R':
 178                                         rfc822 = 1;
 179                                         break;
 180                                 case 's':
 181                                         set_time = 1;
 182                                         if (date_str != NULL)
 183                                                 usage(date_usage);
 184                                         date_str = *argv;
 185                                         break;
 186                                 case 'u':
 187                                         utc = 1;
 188                                         if (putenv("TZ=UTC0") != 0)
 189                                                 fatalError(memory_exhausted, "date");
 190                                         break;
 191                                 case 'd':
 192                                         use_arg = 1;
 193                                         if (date_str != NULL)
 194                                                 usage(date_usage);
 195                                         date_str = *argv;
 196                                         break;
 197                                 case '-':
 198                                         usage(date_usage);
 199                                 }
 200                 } else {
 201                         if ((date_fmt == NULL) && (**argv == '+'))
 202                                 date_fmt = *argv + 1;   /* Skip over the '+' */
 203                         else if (date_str == NULL) {
 204                                 set_time = 1;
 205                                 date_str = *argv;
 206                         } else {
 207                                 usage(date_usage);
 208                         }
 209                 }
 210                 i--;
 211                 argv++;
 212         }
 213
 214
 215         /* Now we have parsed all the information except the date format
 216            which depends on whether the clock is being set or read */
 217
 218         time(&tm);
 219         memcpy(&tm_time, localtime(&tm), sizeof(tm_time));
 220         /* Zero out fields - take her back to midnight! */
 221         if (date_str != NULL) {
 222                 tm_time.tm_sec = 0;
 223                 tm_time.tm_min = 0;
 224                 tm_time.tm_hour = 0;
 225         }
 226
 227         /* Process any date input to UNIX time since 1 Jan 1970 */
 228         if (date_str != NULL) {
 229
 230                 if (strchr(date_str, ':') != NULL) {
 231                         date_conv_ftime(&tm_time, date_str);
 232                 } else {
 233                         date_conv_time(&tm_time, date_str);
 234                 }
 235
 236                 /* Correct any day of week and day of year etc fields */
 237                 tm = mktime(&tm_time);
 238                 if (tm < 0)
 239                         fatalError(invalid_date, "date", date_str);
 240
 241                 /* if setting time, set it */
 242                 if (set_time) {
 243                         if (stime(&tm) < 0) {
 244                                 fatalError("date: can't set date.\n");
 245                         }
 246                 }
 247         }
 248
 249         /* Display output */
 250
 251         /* Deal with format string */
 252         if (date_fmt == NULL) {
 253                 date_fmt = (rfc822
 254                                         ? (utc
 255                                            ? "%a, %_d %b %Y %H:%M:%S GMT"
 256                                            : "%a, %_d %b %Y %H:%M:%S %z")
 257                                         : "%a %b %e %H:%M:%S %Z %Y");
 258
 259         } else if (*date_fmt == '\0') {
 260                 /* Imitate what GNU 'date' does with NO format string! */
 261                 printf("\n");
 262                 exit(TRUE);
 263         }
 264
 265         /* Handle special conversions */
 266
 267         if (strncmp(date_fmt, "%f", 2) == 0) {
 268                 date_fmt = "%Y.%m.%d-%H:%M:%S";
 269         }
 270
 271         /* Print OUTPUT (after ALL that!) */
 272         t_buff = xmalloc(201);
 273         strftime(t_buff, 200, date_fmt, &tm_time);
 274         printf("%s\n", t_buff);
 275
 276         return(TRUE);
 277 }