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\n"
  44         "Display the current time in the given FORMAT, or set the system date.\n"
  45         "\nOptions:\n\t-R\t\toutput RFC-822 compliant date string\n"
  46         "\t-s\t\tset time described by STRING\n"
  47
  48         "\t-u\t\tprint or set Coordinated Universal Time\n";
  49
  50
  51 /* Input parsing code is always bulky - used heavy duty libc stuff as
  52    much as possible, missed out a lot of bounds checking */
  53
  54 /* Default input handling to save suprising some people */
  55
  56 struct tm *date_conv_time(struct tm *tm_time, const char *t_string)
  57 {
  58         int nr;
  59
  60         nr = sscanf(t_string, "%2d%2d%2d%2d%d",
  61                                 &(tm_time->tm_mon),
  62                                 &(tm_time->tm_mday),
  63                                 &(tm_time->tm_hour),
  64                                 &(tm_time->tm_min), &(tm_time->tm_year));
  65
  66         if (nr < 4 || nr > 5) {
  67                 fprintf(stderr, invalid_date, "date", t_string);
  68                 exit(FALSE);
  69         }
  70
  71         /* correct for century  - minor Y2K problem here? */
  72         if (tm_time->tm_year >= 1900)
  73                 tm_time->tm_year -= 1900;
  74         /* adjust date */
  75         tm_time->tm_mon -= 1;
  76
  77         return (tm_time);
  78
  79 }
  80
  81
  82 /* The new stuff for LRP */
  83
  84 struct tm *date_conv_ftime(struct tm *tm_time, const char *t_string)
  85 {
  86         struct tm itm_time, jtm_time, ktm_time, ltm_time, mtm_time, ntm_time;
  87
  88         itm_time = *tm_time;
  89         jtm_time = *tm_time;
  90         ktm_time = *tm_time;
  91         ltm_time = *tm_time;
  92         mtm_time = *tm_time;
  93         ntm_time = *tm_time;
  94
  95         /* Parse input and assign appropriately to tm_time */
  96
  97         if (sscanf(t_string, "%d:%d:%d",
  98                            &itm_time.tm_hour, &itm_time.tm_min, &itm_time.tm_sec) == 3) {
  99
 100                 *tm_time = itm_time;
 101                 return (tm_time);
 102
 103         } else if (sscanf(t_string, "%d:%d",
 104                                           &jtm_time.tm_hour, &jtm_time.tm_min) == 2) {
 105
 106                 *tm_time = jtm_time;
 107                 return (tm_time);
 108
 109         } else if (sscanf(t_string, "%d.%d-%d:%d:%d",
 110                                           &ktm_time.tm_mon,
 111                                           &ktm_time.tm_mday,
 112                                           &ktm_time.tm_hour,
 113                                           &ktm_time.tm_min, &ktm_time.tm_sec) == 5) {
 114
 115                 ktm_time.tm_mon -= 1;   /* Adjust dates from 1-12 to 0-11 */
 116                 *tm_time = ktm_time;
 117                 return (tm_time);
 118
 119         } else if (sscanf(t_string, "%d.%d-%d:%d",
 120                                           &ltm_time.tm_mon,
 121                                           &ltm_time.tm_mday,
 122                                           &ltm_time.tm_hour, &ltm_time.tm_min) == 4) {
 123
 124                 ltm_time.tm_mon -= 1;   /* Adjust dates from 1-12 to 0-11 */
 125                 *tm_time = ltm_time;
 126                 return (tm_time);
 127
 128         } else if (sscanf(t_string, "%d.%d.%d-%d:%d:%d",
 129                                           &mtm_time.tm_year,
 130                                           &mtm_time.tm_mon,
 131                                           &mtm_time.tm_mday,
 132                                           &mtm_time.tm_hour,
 133                                           &mtm_time.tm_min, &mtm_time.tm_sec) == 6) {
 134
 135                 mtm_time.tm_year -= 1900;       /* Adjust years */
 136                 mtm_time.tm_mon -= 1;   /* Adjust dates from 1-12 to 0-11 */
 137                 *tm_time = mtm_time;
 138                 return (tm_time);
 139
 140         } else if (sscanf(t_string, "%d.%d.%d-%d:%d",
 141                                           &ntm_time.tm_year,
 142                                           &ntm_time.tm_mon,
 143                                           &ntm_time.tm_mday,
 144                                           &ntm_time.tm_hour, &ntm_time.tm_min) == 5) {
 145                 ntm_time.tm_year -= 1900;       /* Adjust years */
 146                 ntm_time.tm_mon -= 1;   /* Adjust dates from 1-12 to 0-11 */
 147                 *tm_time = ntm_time;
 148                 return (tm_time);
 149
 150         }
 151
 152         fprintf(stderr, invalid_date, "date", t_string);
 153
 154         exit(FALSE);
 155
 156 }
 157
 158
 159 int date_main(int argc, char **argv)
 160 {
 161         char *date_str = NULL;
 162         char *date_fmt = NULL;
 163         char *t_buff;
 164         int i;
 165         int set_time = 0;
 166         int rfc822 = 0;
 167         int utc = 0;
 168         int use_arg = 0;
 169         time_t tm;
 170         struct tm tm_time;
 171
 172         /* Interpret command line args */
 173         i = --argc;
 174         argv++;
 175         while (i > 0 && **argv) {
 176                 if (**argv == '-') {
 177                         while (i > 0 && *++(*argv))
 178                                 switch (**argv) {
 179                                 case 'R':
 180                                         rfc822 = 1;
 181                                         break;
 182                                 case 's':
 183                                         set_time = 1;
 184                                         if (date_str != NULL)
 185                                                 usage(date_usage);
 186                                         date_str = optarg;
 187                                         break;
 188                                 case 'u':
 189                                         utc = 1;
 190                                         if (putenv("TZ=UTC0") != 0) {
 191                                                 fprintf(stderr, memory_exhausted, "date");
 192                                                 exit(FALSE);
 193                                         }
 194                                         /* Look ma, no break.  Don't fix it either. */
 195                                 case 'd':
 196                                         use_arg = 1;
 197                                         if (date_str != NULL)
 198                                                 usage(date_usage);
 199                                         date_str = optarg;
 200                                         break;
 201                                 case '-':
 202                                         usage(date_usage);
 203                                 }
 204                 } else {
 205                         if ((date_fmt == NULL) && (strcmp(*argv, "+") == 0))
 206                                 date_fmt = *argv;
 207                         else if (date_str == NULL) {
 208                                 set_time = 1;
 209                                 date_str = *argv;
 210                         } else {
 211                                 usage(date_usage);
 212                         }
 213                 }
 214                 i--;
 215                 argv++;
 216         }
 217
 218
 219         /* Now we have parsed all the information except the date format
 220            which depends on whether the clock is being set or read */
 221
 222         time(&tm);
 223         memcpy(&tm_time, localtime(&tm), sizeof(tm_time));
 224         /* Zero out fields - take her back to midnight! */
 225         if (date_str != NULL) {
 226                 tm_time.tm_sec = 0;
 227                 tm_time.tm_min = 0;
 228                 tm_time.tm_hour = 0;
 229         }
 230
 231         /* Process any date input to UNIX time since 1 Jan 1970 */
 232         if (date_str != NULL) {
 233
 234                 if (strchr(date_str, ':') != NULL) {
 235                         date_conv_ftime(&tm_time, date_str);
 236                 } else {
 237                         date_conv_time(&tm_time, date_str);
 238                 }
 239
 240                 /* Correct any day of week and day of year etc fields */
 241                 tm = mktime(&tm_time);
 242                 if (tm < 0) {
 243                         fprintf(stderr, invalid_date, "date", date_str);
 244                         exit(FALSE);
 245                 }
 246
 247                 /* if setting time, set it */
 248                 if (set_time) {
 249                         if (stime(&tm) < 0) {
 250                                 fprintf(stderr, "date: can't set date.\n");
 251                                 exit(FALSE);
 252                         }
 253                 }
 254         }
 255
 256         /* Display output */
 257
 258         /* Deal with format string */
 259         if (date_fmt == NULL) {
 260                 date_fmt = (rfc822
 261                                         ? (utc
 262                                            ? "%a, %_d %b %Y %H:%M:%S GMT"
 263                                            : "%a, %_d %b %Y %H:%M:%S %z")
 264                                         : "%a %b %e %H:%M:%S %Z %Y");
 265
 266         } else if (*date_fmt == '\0') {
 267                 /* Imitate what GNU 'date' does with NO format string! */
 268                 printf("\n");
 269                 exit(TRUE);
 270         }
 271
 272         /* Handle special conversions */
 273
 274         if (strncmp(date_fmt, "%f", 2) == 0) {
 275                 date_fmt = "%Y.%m.%d-%H:%M:%S";
 276         }
 277
 278         /* Print OUTPUT (after ALL that!) */
 279         t_buff = xmalloc(201);
 280         strftime(t_buff, 200, date_fmt, &tm_time);
 281         printf("%s\n", t_buff);
 282
 283         exit(TRUE);
 284
 285 }